Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Masaru Tanaka Last modified date:2022.06.22

Professor / Soft-materials chemistry / Department of Soft Materials Chemistry / Institute for Materials Chemistry and Engineering


Papers
1. Tomoya Ueda, Daiki Murakami, Masaru Tanaka, Effect of amount of hydrated water and mobility of hydrated poly(2-methoxyethyl acrylate) on denaturation of adsorbed fibrinogen, JOURNAL OF POLYMER SCIENCE, 10.1002/pol.20210496, 2021.08, In this study, a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), was grafted onto a gold substrate with various grafting densities (sigma) (sigma = 0-0.18 chains nm(-2)), and the amount of hydrated water and mobility of the polymer chain interacting with water molecules were quantitatively evaluated using a quartz crystal microbalance with an admittance system. The amount of hydrated water decreased with increasing sigma. By contrast, the mobility of the hydrated PMEA was maximum at sigma approximate to 0.12 chains nm(-2), revealing that the amount of high-mobility water at sigma = 0.12 was higher than that at other densities. The degree of denaturation of the adsorbed fibrinogen was evaluated based on the hydrodynamic water ratio and viscoelasticity, and was found to increase with increasing sigma. The denaturation of adsorbed fibrinogen was suppressed when both the amount of hydrated water and the mobility of hydrated PMEA were high. This study demonstrates that the interfacial state of the polymer chains hydrated in water is important for blood compatibility..
2. T. Kanamaru, M. Araki, R. Takahashi, S. Fujii, T. Shikata, D. Murakami, M. Tanaka, K. Sakurai, The first observation of the hydration layer around polymer chain by scattering and its relationship to thromboresistance; dilute solution properties of PMEA in THF/water, The Journal of Physical Chemistry B, 2021.06.
3. S. Liu, S. Kobayashi, T. Sonoda, M. Tanaka, Poly(tertiary amide acrylate) (Co)polymers Inspired by Poly(2-oxazoline)s: Their Blood Compatibility and Hydration States, Biomacromolecules, 10.1021/acs.biomac.1c0041, 2021.05.
4. A. T. Kuo, S. Urata, R. Koguchi, T. Sonoda, S. Kobayashi, M. Tanaka, Effects of Side-Chain Spacing and Length on Hydration States of the Poly(2-methoxyethyl acrylate) Analogs: A Molecular Dynamics Study, ACS Biomaterials Science & Engineering, 2021.05.
5. 6.R. Anjum, K. Nishida, H. Matsumoto, D. Murakami, S. Kobayashi, T. Anada, M. Tanaka, Attachment and Growth of Fibroblast Cells on Poly(2-methoxyethyl acrylate) Analog Polymers as Coating Materials, Coatings, 2021.05.
6. A. Tsujimoto, H. Uehara, H. Yoshida, M. Nishio, K. Furuta, T. Inui, A. Matsumoto, S. Morita, M. Tanaka, C. Kojima, Different Hydration States and Passive Tumor Targeting Ability of Polyethylene Glycol-modified Dendrimers with High and Low PEG density, Materials Science & Engineering C, 2021.04.
7. V. Montagna, J. Takahashi, M-Y. Tsai, T. Ota, N. Zivic, S. Kawaguchi, T. Kato, M. Tanaka, H. Sardón, K. Fukushima, Methoxy-Functionalized Glycerol-Based Aliphatic Polycarbonate: Organocatalytic Synthesis, Blood Compatibility, and Hydrolytic Property, ACS Biomaterials Science & Engineering, 表紙掲載, 2021.02.
8. Y. Toyokawa, S. Kobayashi, H. Tsuchiya, T. Shibuya, M. Aoki, J. Sumiya, S. Ooyama, T. Ishizawa, N. Makino, Y. Ueno, M. Tanaka, A fully covered self-expandable metallic stent coated with poly (2-methoxyethyl acrylate) and its derivative: In vitro evaluation of early-stage biliary sludge formation inhibition, Materials Science & Engineering C, 2021.02.
9. T. Ueda, D. Murakami, M. Tanaka, Effect of Interfacial Structure Based on Grafting Density of Poly(2-Methoxyethyl Acrylate) on Blood Compatibility, Colloids and Surfaces B: Biointerfaces, 2021.02.
10. M. Tanaka, S. Morita, T. Hayashi, Role of Interfacial Water in Determining the Interaction of Proteins and Cells with Hydrated Materials, Colloids and Surfaces B: Biointerfaces, 2021.02.
11. A.T. Kuo, S. Urata, R. Koguchi, T. Sonoda, S. Kobayashi, M. Tanaka, Molecular Dynamics Study on the Water Mobility and Side-chain Flexibility of Hydrated Poly(ω-methoxyalkyl acrylate)s, ACS Biomaterials Science & Engineering, 2020.12.
12. T. Sonoda, S. Kobayashi, K. Herai, M. Tanaka, Side chain spacing control of derivatives of poly(2-methoxyethyl acrylate): impact on hydration states and antithrombogenicity, Macromolecules, 2020.12.
13. Masaru Tanaka, Shigeaki Morita, Tomohiro Hayashi, Role of interfacial water in determining the interactions of proteins and cells with hydrated materials., Colloids and surfaces. B, Biointerfaces, 10.1016/j.colsurfb.2020.111449, 198, 111449-111449, 2020.11, Water molecules play a crucial role in biointerfacial interactions, including protein adsorption and desorption. To understand the role of water in the interaction of proteins and cells at biological interfaces, it is important to compare particular states of hydration water with various physicochemical properties of hydrated biomaterials. In this review, we discuss the fundamental concepts for determining the interactions of proteins and cells with hydrated materials along with selected examples corresponding to our recent studies, including poly(2-methoxyethyl acrylate) (PMEA), PMEA derivatives, and other biomaterials. The states of water were analyzed by differential scanning calorimetry, in situ attenuated total reflection infrared spectroscopy, and surface force measurements. We found that intermediate water which is loosely bound to a biomaterial, is a useful indicator of the bioinertness of material surfaces. This finding on intermediate water provides novel insights and helps develop novel experimental models for understanding protein adsorption in a wide range of materials, such as those used in biomedical applications..
14. S. Nishimura, T. Ueda, S. Kobayashi, M. Tanak, Silsesquioxane/Poly(2-methoxyethyl acrylate) Hybrid with Both Antithrombotic and Endothelial Cell Adhesive Properties, ACS Applied Polymer Materials, 2020.10.
15. A.T. Kuo, T. Sonoda, S. Urata, R. Koguchi, S. Kobayashi, M. Tanaka, Elucidating the Feature of Intermediate Water in Hydrated Poly(ω-methoxyalkyl acrylate)s by Molecular Dynamics Simulation and Differential Scanning Calorimetry Measurement, ACS Biomater. Sci. Eng., 2020.07.
16. R. Koguchi, K. Jankova, Y. Hayasaka, D. Kobayashi, Y. Amino, T. Miyajima, S. Kobayashi, D. Murakami, K. Yamamoto, M. Tanaka, Understanding the effect of hydration on the bio-inert properties of HEMA copolymers with small amounts of amino- or/and fluorine-containing monomers, ACS Biomater. Sci. Eng., 2020.05.
17. Meng Yu Tsai, Fumihiro Aratsu, Shogo Sekida, Shingo Kobayashi, Masaru Tanaka, Blood-Compatible Poly(2-methoxyethyl acrylate) Induces Blebbing-like Phenomenon and Promotes Viability of Tumor Cells in Serum-Free Medium, ACS Applied Bio Materials, 10.1021/acsabm.9b00885, 3, 4, 1858-1864, 2020.04, Circulating tumor cells (CTCs) are highly related to tumor metastasis and an effective technique of detecting/isolating CTCs has been expected to be established for tumor treatments. Previously, we reported that platelets cannot adhere but tumor cells can adhere on poly(2-methoxyethyl acrylate) (PMEA) substrate. In this study, we report that cell viability of human fibrosarcoma (HT-1080) cells was promoted on PMEA substrate in serum-free medium. The significant blebbing-like phenomenon and spontaneous formation of cell aggregation were observed on PMEA substrate. Moreover, cell viability was promoted by activation of Akt signaling pathway via N-cadherin-mediated cell-cell contact. These results suggest that not only capture efficiency and purity but also high cell viability of CTCs can be accomplished by using PMEA substrate. PMEA substrate can be a promising candidate for medical applications such as in vitro screening of anticancer drugs and is an excellent platform for studies and diagnoses of tumor migration and metastasis..
18. Meng Yu Tsai, Fumihiro Aratsu, Shogo Sekida, Shingo Kobayashi, Masaru Tanaka, Blood-Compatible Poly(2-methoxyethyl acrylate) Induces Blebbing-like Phenomenon and Promotes Viability of Tumor Cells in Serum-Free Medium, ACS Applied Bio Materials, 10.1021/acsabm.9b00885, 3, 4, 1858-1864, 2020.04, Circulating tumor cells (CTCs) are highly related to tumor metastasis and an effective technique of detecting/isolating CTCs has been expected to be established for tumor treatments. Previously, we reported that platelets cannot adhere but tumor cells can adhere on poly(2-methoxyethyl acrylate) (PMEA) substrate. In this study, we report that cell viability of human fibrosarcoma (HT-1080) cells was promoted on PMEA substrate in serum-free medium. The significant blebbing-like phenomenon and spontaneous formation of cell aggregation were observed on PMEA substrate. Moreover, cell viability was promoted by activation of Akt signaling pathway via N-cadherin-mediated cell-cell contact. These results suggest that not only capture efficiency and purity but also high cell viability of CTCs can be accomplished by using PMEA substrate. PMEA substrate can be a promising candidate for medical applications such as in vitro screening of anticancer drugs and is an excellent platform for studies and diagnoses of tumor migration and metastasis..
19. Mayuko Watanabe, Yukiko Tanaka, Daiki Murakami, Masaru Tanaka, Mika Kawai, Tetsu Mitsumata, Optimal Plasticizer Content for Magnetic Elastomers Used for Cell Culture Substrate, CHEMISTRY LETTERS, 10.1246/cl.190929, 49, 3, 280-283, 2020.03, The effect of a magnetic field on the water contact angle for magnetic elastomers with various plasticizer contents was investigated. At a plasticizer content below 60 wt %, there was no change in contact angle when a magnetic field of 370 mT was applied. For magnetic elastomers with a plasticizer content above 65 wt %, a change in contact angle of approximately 8.0 degrees was observed (e.g. 38 degrees at 0 mT and 46 degrees at 370 mT for 65 wt % plasticizer content). Dynamic viscoelastic measurements showed that magnetic elastomers with a plasticizer content below 60 wt % demonstrate the magnetorheological (MR) effect with changes in storage modulus higher than similar to 1 MPa. Atomic force microscopy for magnetic elastomer with a plasticizer content of 50 wt % revealed that the averaged Young's modulus was 233 +/- 52.1 kPa at 370 mT and 83 +/- 5.4 kPa at 0 mT, indicating that the MR effect is caused not only on a bulk but also on a mesoscopic scale. Magnetic elastomers specialized for cell culture were obtained by optimizing the plasticizer content, that exhibit the MR effect with changes in storage modulus from 1.3 x 10(4) Pa to 9.4 x 10(5) without changing the surface properties..
20. D. Murakami, Y. Segami, T. Ueda, M. Tanaka, Control of interfacial structures and anti-platelet adhesion property of blood-compatible random copolymers, J. Biomater. Sci. Polym. Ed., 2020.02.
21. Mayuko Watanabe, Yukiko Tanaka, Daiki Murakami, Masaru Tanaka, Mika Kawai, Tetsu Mitsumata, Optimal plasticizer content for magnetic elastomers used for cell culture substrate, Chemistry Letters, 10.1246/cl.190929, 49, 3, 280-283, 2020.01, The effect of a magnetic field on the water contact angle for magnetic elastomers with various plasticizer contents was investigated. At a plasticizer content below 60 wt %, there was no change in contact angle when a magnetic field of 370 mT was applied. For magnetic elastomers with a plasticizer content above 65 wt %, a change in contact angle of approximately 8.0° was observed (e.g. 38° at 0 mT and 46° at 370 mT for 65 wt % plasticizer content). Dynamic viscoelastic measurements showed that magnetic elastomers with a plasticizer content below 60 wt % demonstrate the magnetorheological (MR) effect with changes in storage modulus higher than 31 MPa. Atomic force microscopy for magnetic elastomer with a plasticizer content of 50 wt % revealed that the averaged Young’s modulus was 233 « 52.1 kPa at 370 mT and 83 « 5.4 kPa at 0 mT, indicating that the MR effect is caused not only on a bulk but also on a mesoscopic scale. Magnetic elastomers specialized for cell culture were obtained by optimizing the plasticizer content, that exhibit the MR effect with changes in storage modulus from 1.3.
22. Mayuko Watanabe, Yukiko Tanaka, Daiki Murakami, Masaru Tanaka, Mika Kawai, Tetsu Mitsumata, Optimal plasticizer content for magnetic elastomers used for cell culture substrate, Chemistry Letters, 10.1246/cl.190929, 49, 3, 280-283, 2020.01, The effect of a magnetic field on the water contact angle for magnetic elastomers with various plasticizer contents was investigated. At a plasticizer content below 60 wt %, there was no change in contact angle when a magnetic field of 370 mT was applied. For magnetic elastomers with a plasticizer content above 65 wt %, a change in contact angle of approximately 8.0° was observed (e.g. 38° at 0 mT and 46° at 370 mT for 65 wt % plasticizer content). Dynamic viscoelastic measurements showed that magnetic elastomers with a plasticizer content below 60 wt % demonstrate the magnetorheological (MR) effect with changes in storage modulus higher than 31 MPa. Atomic force microscopy for magnetic elastomer with a plasticizer content of 50 wt % revealed that the averaged Young’s modulus was 233 « 52.1 kPa at 370 mT and 83 « 5.4 kPa at 0 mT, indicating that the MR effect is caused not only on a bulk but also on a mesoscopic scale. Magnetic elastomers specialized for cell culture were obtained by optimizing the plasticizer content, that exhibit the MR effect with changes in storage modulus from 1.3.
23. Katja Jankova, Irakli Javakhishvili, Shingo Kobayashi, Ryohei Koguchi, Daiki Murakami, Toshiki Sonoda, Masaru Tanaka, Hydration States and Blood Compatibility of Hydrogen-Bonded Supramolecular Poly(2-methoxyethyl acrylate), ACS Applied Bio Materials, 10.1021/acsabm.9b00363, 2, 10, 4154-4161, 2019.10, The practical use of the viscous liquid polymer, poly(2-methoxyethyl acrylate) (PMEA), was expanded from thin films with excellent blood compatibility to thick coatings and free-standing films without essentially sacrificing its blood compatibility. This was undertaken by creating multiple hydrogen-bonding polymer networks by introducing a functional methacrylic monomer bearing a 6-methyl-2-ureido-4[1H]-pyrimidone group in the PMEA backbone via free radical copolymerization. The hydrogen-bonded PMEA (H-PMEA) contained about 6 mol % of the functional monomer in the copolymer. These functional monomers as physical cross-links are distributed in the PMEA matrix with a Tg of -35 °C, making H-PMEA a solid rubber-like material with recoverable tensile strain. Additionally, mechanical tests revealed its tensile strength, and thermogravimetric analyses confirmed its higher thermostability. The dry and hydration states of H-PMEA were assessed by differential scanning calorimetry, contact angle, and atomic force microscopy measurements. Comparison with viscous PMEA was made. For the first time, we included PVC alongside PET, the surface we usually use as a negative control, in the platelet adhesion test with human blood, and found out that 1.5 times more platelets adhered onto the PVC surface than onto the PET surface, while H-PMEA proved to have a clear edge. Thus, H-PMEA may serve as a suitable replacement for polymers in products contacting blood as it shows potential for making free-standing films, thick coatings, implants, and articles with various geometries for the medicinal industry..
24. Katja Jankova, Irakli Javakhishvili, Shingo Kobayashi, Ryohei Koguchi, Daiki Murakami, Toshiki Sonoda, Masaru Tanaka, Hydration States and Blood Compatibility of Hydrogen-Bonded Supramolecular Poly(2-methoxyethyl acrylate), ACS Applied Bio Materials, 10.1021/acsabm.9b00363, 2, 10, 4154-4161, 2019.10, The practical use of the viscous liquid polymer, poly(2-methoxyethyl acrylate) (PMEA), was expanded from thin films with excellent blood compatibility to thick coatings and free-standing films without essentially sacrificing its blood compatibility. This was undertaken by creating multiple hydrogen-bonding polymer networks by introducing a functional methacrylic monomer bearing a 6-methyl-2-ureido-4[1H]-pyrimidone group in the PMEA backbone via free radical copolymerization. The hydrogen-bonded PMEA (H-PMEA) contained about 6 mol % of the functional monomer in the copolymer. These functional monomers as physical cross-links are distributed in the PMEA matrix with a Tg of -35 °C, making H-PMEA a solid rubber-like material with recoverable tensile strain. Additionally, mechanical tests revealed its tensile strength, and thermogravimetric analyses confirmed its higher thermostability. The dry and hydration states of H-PMEA were assessed by differential scanning calorimetry, contact angle, and atomic force microscopy measurements. Comparison with viscous PMEA was made. For the first time, we included PVC alongside PET, the surface we usually use as a negative control, in the platelet adhesion test with human blood, and found out that 1.5 times more platelets adhered onto the PVC surface than onto the PET surface, while H-PMEA proved to have a clear edge. Thus, H-PMEA may serve as a suitable replacement for polymers in products contacting blood as it shows potential for making free-standing films, thick coatings, implants, and articles with various geometries for the medicinal industry..
25. Hydration States and Blood Compatibility of Hydrogen-Bonded Supramolecular Poly(2-methoxyethyl acrylate)
Copyright © 2019 American Chemical Society. The practical use of the viscous liquid polymer, poly(2-methoxyethyl acrylate) (PMEA), was expanded from thin films with excellent blood compatibility to thick coatings and free-standing films without essentially sacrificing its blood compatibility. This was undertaken by creating multiple hydrogen-bonding polymer networks by introducing a functional methacrylic monomer bearing a 6-methyl-2-ureido-4[1H]-pyrimidone group in the PMEA backbone via free radical copolymerization. The hydrogen-bonded PMEA (H-PMEA) contained about 6 mol % of the functional monomer in the copolymer. These functional monomers as physical cross-links are distributed in the PMEA matrix with a Tg of -35 °C, making H-PMEA a solid rubber-like material with recoverable tensile strain. Additionally, mechanical tests revealed its tensile strength, and thermogravimetric analyses confirmed its higher thermostability. The dry and hydration states of H-PMEA were assessed by differential scanning calorimetry, contact angle, and atomic force microscopy measurements. Comparison with viscous PMEA was made. For the first time, we included PVC alongside PET, the surface we usually use as a negative control, in the platelet adhesion test with human blood, and found out that 1.5 times more platelets adhered onto the PVC surface than onto the PET surface, while H-PMEA proved to have a clear edge. Thus, H-PMEA may serve as a suitable replacement for polymers in products contacting blood as it shows potential for making free-standing films, thick coatings, implants, and articles with various geometries for the medicinal industry..
26. Ryohei Koguchi, Katja Jankova, Noriko Tanabe, Yosuke Amino, Yuki Hayasaka, Daisuke Kobayashi, Tatsuya Miyajima, Kyoko Yamamoto, Masaru Tanaka, Controlling the Hydration Structure with a Small Amount of Fluorine to Produce Blood Compatible Fluorinated Poly(2-methoxyethyl acrylate), Biomacromolecules, 10.1021/acs.biomac.9b00201, 20, 6, 2265-2275, 2019.06, Poly(2-methoxyethyl acrylate) (PMEA) shows excellent blood compatibility because of the existence of intermediate water. Various modifications of PMEA by changing its main or side chain's chemical structure allowed tuning of the water content and the blood compatibility of numerous novel polymers. Here, we exploit a possibility of manipulating the surface hydration structure of PMEA by incorporation of small amounts of hydrophobic fluorine groups in MEA polymers using atom-transfer radical polymerization and the (macro) initiator concept. Two kinds of fluorinated MEA polymers with similar molecular weights and the same 5.5 mol % of fluorine content were synthesized using the bromoester of 2,2,3,3,4,4,5,5,6,6,7,7,8,8-pentadecafluoro-1-octanol (F15) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) as (macro) initiators, appearing liquid and solid at room temperature, respectively. The fibrinogen adsorption of the two varieties of fluorinated MEA polymers was different, which could not be explained only by the bulk hydration structure. Both polymers show a nanostructured morphology in the hydrated state with different sizes of the features. The measured elastic modulus of the domains appearing in atomic force microscopy and the intermediate water content shed light on the distinct mechanism of blood compatibility. Contact angle measurements reveal the surface hydration dynamics - while in the hydrated state, F15-b-PMEA reorients easily to the surface exposing its PMEA part to the water, the small solid PTFEMA block with high glass-transition temperature suppresses the movement of PTFEMA-b-PMEA and its reconstruction on the surface. These findings illustrate that in order to make a better blood compatible polymer, the chains containing sufficient intermediate water need to be mobile and efficiently oriented to the water surface..
27. Ryohei Koguchi, Katja Jankova, Noriko Tanabe, Yosuke Amino, Yuki Hayasaka, Daisuke Kobayashi, Tatsuya Miyajima, Kyoko Yamamoto, Masaru Tanaka, Controlling the Hydration Structure with a Small Amount of Fluorine to Produce Blood Compatible Fluorinated Poly(2-methoxyethyl acrylate), Biomacromolecules, 10.1021/acs.biomac.9b00201, 20, 6, 2265-2275, 2019.06, Poly(2-methoxyethyl acrylate) (PMEA) shows excellent blood compatibility because of the existence of intermediate water. Various modifications of PMEA by changing its main or side chain's chemical structure allowed tuning of the water content and the blood compatibility of numerous novel polymers. Here, we exploit a possibility of manipulating the surface hydration structure of PMEA by incorporation of small amounts of hydrophobic fluorine groups in MEA polymers using atom-transfer radical polymerization and the (macro) initiator concept. Two kinds of fluorinated MEA polymers with similar molecular weights and the same 5.5 mol % of fluorine content were synthesized using the bromoester of 2,2,3,3,4,4,5,5,6,6,7,7,8,8-pentadecafluoro-1-octanol (F15) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) as (macro) initiators, appearing liquid and solid at room temperature, respectively. The fibrinogen adsorption of the two varieties of fluorinated MEA polymers was different, which could not be explained only by the bulk hydration structure. Both polymers show a nanostructured morphology in the hydrated state with different sizes of the features. The measured elastic modulus of the domains appearing in atomic force microscopy and the intermediate water content shed light on the distinct mechanism of blood compatibility. Contact angle measurements reveal the surface hydration dynamics - while in the hydrated state, F15-b-PMEA reorients easily to the surface exposing its PMEA part to the water, the small solid PTFEMA block with high glass-transition temperature suppresses the movement of PTFEMA-b-PMEA and its reconstruction on the surface. These findings illustrate that in order to make a better blood compatible polymer, the chains containing sufficient intermediate water need to be mobile and efficiently oriented to the water surface..
28. Teppei Araki, Fumiaki Yoshida, Takafumi Uemura, Yuki Noda, Shusuke Yoshimoto, Taro Kaiju, Takafumi Suzuki, Hiroki Hamanaka, Kousuke Baba, Hideki Hayakawa, Taiki Yabumoto, Hideki Mochizuki, Shingo Kobayashi, Masaru Tanaka, Masayuki Hirata, Tsuyoshi Sekitani, Long-Term Implantable, Flexible, and Transparent Neural Interface Based on Ag/Au Core–Shell Nanowires, Advanced Healthcare Materials, 10.1002/adhm.201900130, 8, 10, 2019.05, Neural interfaces enabling light transmittance rely on optogenetics to control and monitor specific neural activity, thereby facilitating deeper understanding of intractable diseases. This study reports the material strategy underlying an optogenetic neural interface comprising stretchable and transparent conductive tracks and capable of demonstrating high biocompatibility after long-term (5-month) implantation. Ag/Au core–shell nanowires contribute toward improving track performance in terms of stretchability (<60% strain), transparency (<83%), and electrical resistance (15 Ω sq−1). The neural interface integrated with gel-coated exterior microelectrodes preserves low impedance (1.1–3.2 Ω cm2) in a saline solution over the evaluated 5-month period. Besides the use of efficient conductive materials, surface treatment using antithrombogenic polymer tends to prevent the growth of granulation tissue, thereby facilitating clear monitoring of electrocorticograms (ECoG) in a rodent during chronic implantation. The flexible and transparent neural interface pathologically exhibits noncytotoxicity and low inflammatory response while efficiently recording evoked ECoG in a nonhuman primate via optogenetic stimulation. The proposed highly reliable interface can be employed in multifaceted approaches for translational research based on chronic implants..
29. Teppei Araki, Fumiaki Yoshida, Takafumi Uemura, Yuki Noda, Shusuke Yoshimoto, Taro Kaiju, Takafumi Suzuki, Hiroki Hamanaka, Kousuke Baba, Hideki Hayakawa, Taiki Yabumoto, Hideki Mochizuki, Shingo Kobayashi, Masaru Tanaka, Masayuki Hirata, Tsuyoshi Sekitani, Long-Term Implantable, Flexible, and Transparent Neural Interface Based on Ag/Au Core–Shell Nanowires, Advanced Healthcare Materials, 10.1002/adhm.201900130, 8, 10, 2019.05, Neural interfaces enabling light transmittance rely on optogenetics to control and monitor specific neural activity, thereby facilitating deeper understanding of intractable diseases. This study reports the material strategy underlying an optogenetic neural interface comprising stretchable and transparent conductive tracks and capable of demonstrating high biocompatibility after long-term (5-month) implantation. Ag/Au core–shell nanowires contribute toward improving track performance in terms of stretchability (<60% strain), transparency (<83%), and electrical resistance (15 Ω sq−1). The neural interface integrated with gel-coated exterior microelectrodes preserves low impedance (1.1–3.2 Ω cm2) in a saline solution over the evaluated 5-month period. Besides the use of efficient conductive materials, surface treatment using antithrombogenic polymer tends to prevent the growth of granulation tissue, thereby facilitating clear monitoring of electrocorticograms (ECoG) in a rodent during chronic implantation. The flexible and transparent neural interface pathologically exhibits noncytotoxicity and low inflammatory response while efficiently recording evoked ECoG in a nonhuman primate via optogenetic stimulation. The proposed highly reliable interface can be employed in multifaceted approaches for translational research based on chronic implants..
30. R. Koguchi, K. Jankova, N. Tanabe, Y. Amino, Y. Hayasaka, D. Kabayashi, T. Miyajima, K. Yamamoto, M. Tanaka, Controlling the hydration structure with small amount of fluorine to produce blood compatible fluorinated poly(2-methoxyethyl acrylate), Biomacromolecules, 10.1021/acs.biomac.9b00201, 2019.05.
31. Teppei Araki, Fumiaki Yoshida, Takafumi Uemura, Yuki Noda, Shusuke Yoshimoto, Taro Kaiju, Takafumi Suzuki, Hiroki Hamanaka, Kousuke Baba, Hideki Hayakawa, Taiki Yabumoto, Hideki Mochizuki, Shingo Kobayashi, Masaru Tanaka, Masayuki Hirata, Tsuyoshi Sekitani, Long-Term Implantable, Flexible, and Transparent Neural Interface Based on Ag/Au Core–Shell Nanowires, Advanced Healthcare Materials, 10.1002/adhm.201900130, 8, 10, 2019.05, © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Neural interfaces enabling light transmittance rely on optogenetics to control and monitor specific neural activity, thereby facilitating deeper understanding of intractable diseases. This study reports the material strategy underlying an optogenetic neural interface comprising stretchable and transparent conductive tracks and capable of demonstrating high biocompatibility after long-term (5-month) implantation. Ag/Au core–shell nanowires contribute toward improving track performance in terms of stretchability (<60% strain), transparency (<83%), and electrical resistance (15 Ω sq−1). The neural interface integrated with gel-coated exterior microelectrodes preserves low impedance (1.1–3.2 Ω cm2) in a saline solution over the evaluated 5-month period. Besides the use of efficient conductive materials, surface treatment using antithrombogenic polymer tends to prevent the growth of granulation tissue, thereby facilitating clear monitoring of electrocorticograms (ECoG) in a rodent during chronic implantation. The flexible and transparent neural interface pathologically exhibits noncytotoxicity and low inflammatory response while efficiently recording evoked ECoG in a nonhuman primate via optogenetic stimulation. The proposed highly reliable interface can be employed in multifaceted approaches for translational research based on chronic implants..
32. An Tsung Kuo, Shingo Urata, Ryohei Koguchi, Kyoko Yamamoto, Masaru Tanaka, Analyses of equilibrium water content and blood compatibility for Poly(2-methoxyethyl acrylate) by molecular dynamics simulation, polymer, 10.1016/j.polymer.2019.03.001, 170, 76-84, 2019.04, Water structures of hydrated polymers have been suggested to directly influence the biomolecules’ adsorption. We conducted a serial of molecular dynamics simulations to investigate the water structures of hydrated poly(2-methoxyethyl acrylate) (PMEA). According to the calculated IR spectra of water molecules categorized into four binding sites in hydrated PMEA, most of water molecules at water content less than 3 wt% are water molecules interacting with two carbonyl groups, corresponding to experimental observed non-freezing water. In addition, we found two-stage variation of the non-bound water content with increasing the water content. The turnover point can be regarded as the saturation point and be used to estimate the equilibrium water content (EWC). Furthermore, the ratio of bound water content to polymer oxygen content was found to be a possible index for predicting the platelet adhesion of polymers. The findings will be useful for developing new biomaterials containing oxygen moieties in the medical applications..
33. An Tsung Kuo, Shingo Urata, Ryohei Koguchi, Kyoko Yamamoto, Masaru Tanaka, Analyses of equilibrium water content and blood compatibility for Poly(2-methoxyethyl acrylate) by molecular dynamics simulation, polymer, 10.1016/j.polymer.2019.03.001, 170, 76-84, 2019.04, Water structures of hydrated polymers have been suggested to directly influence the biomolecules’ adsorption. We conducted a serial of molecular dynamics simulations to investigate the water structures of hydrated poly(2-methoxyethyl acrylate) (PMEA). According to the calculated IR spectra of water molecules categorized into four binding sites in hydrated PMEA, most of water molecules at water content less than 3 wt% are water molecules interacting with two carbonyl groups, corresponding to experimental observed non-freezing water. In addition, we found two-stage variation of the non-bound water content with increasing the water content. The turnover point can be regarded as the saturation point and be used to estimate the equilibrium water content (EWC). Furthermore, the ratio of bound water content to polymer oxygen content was found to be a possible index for predicting the platelet adhesion of polymers. The findings will be useful for developing new biomaterials containing oxygen moieties in the medical applications..
34. Analyses of equilibrium water content and blood compatibility for Poly(2-methoxyethyl acrylate) by molecular dynamics simulation.
35. Masahiro Okada, Emilio Satoshi Hara, Daisuke Kobayashi, Shoki Kai, Keiko Ogura, Masaru Tanaka, Takuya Matsumoto, Intermediate water on calcium phosphate minerals
ITS origin and role in crystal growth, ACS Applied Bio Materials, 10.1021/acsabm.9b00014, 2, 3, 981-986, 2019.03, Water molecules are known to play crucial roles both in the formation and biological function of materials. Herein, we show the presence of “intermediate water” on an inorganic solid material, hydroxyapatite. In vitro experiments revealed that Mg substitution of apatite significantly enriched the amount of intermediate water, possibly due to the proton transfer to a hydrogen-bonded network of water around HPO42− on divalent-cation-deficient apatite surfaces. The intermediate water formation related to a markedl su ressed rotein adsor tion on a atite Anal sis of bone a atites suggested that the intermediate water on minerals could play crucial roles in regulating crystal growth..
36. Masahiro Okada, Emilio Satoshi Hara, Daisuke Kobayashi, Shoki Kai, Keiko Ogura, Masaru Tanaka, Takuya Matsumoto, Intermediate water on calcium phosphate minerals
ITS origin and role in crystal growth, ACS Applied Bio Materials, 10.1021/acsabm.9b00014, 2, 3, 981-986, 2019.03, Water molecules are known to play crucial roles both in the formation and biological function of materials. Herein, we show the presence of “intermediate water” on an inorganic solid material, hydroxyapatite. In vitro experiments revealed that Mg substitution of apatite significantly enriched the amount of intermediate water, possibly due to the proton transfer to a hydrogen-bonded network of water around HPO42− on divalent-cation-deficient apatite surfaces. The intermediate water formation related to a markedl su ressed rotein adsor tion on a atite Anal sis of bone a atites suggested that the intermediate water on minerals could play crucial roles in regulating crystal growth..
37. Daiki Murakami, Nami Mawatari, Toshiki Sonoda, Aki Kashiwazaki, Masaru Tanaka, Effect of the Molecular Weight of Poly(2-methoxyethyl acrylate) on Interfacial Structure and Blood Compatibility, Langmuir, 10.1021/acs.langmuir.8b02971, 35, 7, 2808-2813, 2019.02, The blood-compatible polymer poly(2-methoxyethyl acrylate) (PMEA) is composed of nanometer-scale interfacial structures because of the phase separation of the polymer and water at the PMEA/phosphate-buffered saline (PBS) interface. We synthesized PMEA with four different molecular weights (19, 30, 44, and 183 kg/mol) to investigate the effect of the molecular weight on the interfacial structures and blood compatibility. The amounts of intermediate water and fibrinogen adsorption were not affected by the molecular weight of PMEA. In contrast, the degree of denaturation of adsorbed fibrinogen molecules and platelet adhesion increased as the molecular weight increased. Atomic force microscopy observation revealed that the domain size of the microphase separation structures observed at the PMEA/PBS interfaces drastically (nearly 3 times in the mean area of a domain) changed with the molecular weight. PMEA with a lower molecular weight showed a smaller polymer-rich domain size, as expected on the basis of the microphase separation of polymer-rich and water-rich domains. The small domain size suppressed the aggregation and denaturation of adsorbed fibrinogen molecules because only a few fibrinogen molecules were adsorbed on a domain. Increasing the domain size enhanced the denaturation of adsorbed fibrinogen molecules. Controlling the interfacial structures is crucial for ensuring the blood compatibility of polymer interfaces..
38. Daiki Murakami, Nami Mawatari, Toshiki Sonoda, Aki Kashiwazaki, Masaru Tanaka, Effect of the Molecular Weight of Poly(2-methoxyethyl acrylate) on Interfacial Structure and Blood Compatibility, Langmuir, 10.1021/acs.langmuir.8b02971, 35, 7, 2808-2813, 2019.02, The blood-compatible polymer poly(2-methoxyethyl acrylate) (PMEA) is composed of nanometer-scale interfacial structures because of the phase separation of the polymer and water at the PMEA/phosphate-buffered saline (PBS) interface. We synthesized PMEA with four different molecular weights (19, 30, 44, and 183 kg/mol) to investigate the effect of the molecular weight on the interfacial structures and blood compatibility. The amounts of intermediate water and fibrinogen adsorption were not affected by the molecular weight of PMEA. In contrast, the degree of denaturation of adsorbed fibrinogen molecules and platelet adhesion increased as the molecular weight increased. Atomic force microscopy observation revealed that the domain size of the microphase separation structures observed at the PMEA/PBS interfaces drastically (nearly 3 times in the mean area of a domain) changed with the molecular weight. PMEA with a lower molecular weight showed a smaller polymer-rich domain size, as expected on the basis of the microphase separation of polymer-rich and water-rich domains. The small domain size suppressed the aggregation and denaturation of adsorbed fibrinogen molecules because only a few fibrinogen molecules were adsorbed on a domain. Increasing the domain size enhanced the denaturation of adsorbed fibrinogen molecules. Controlling the interfacial structures is crucial for ensuring the blood compatibility of polymer interfaces..
39. Effect of the Molecular Weight of Poly(2-methoxyethyl acrylate) on Interfacial Structure and Blood Compatibility.
40. Daiki Murakami, Yuto Segami, Tomoya Ueda, Masaru Tanaka, Control of interfacial structures and anti-platelet adhesion property of blood-compatible random copolymers, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2019.1680930, 2019.01, Fibrinogen adsorption behavior on the blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), non-blood-compatible polymer, poly(n-butyl acrylate) (PBA), and random copolymers of both were examined. Adsorption and denaturation of fibrinogen on the polymers increased as the ratio of PBA increased. The incremental change corresponded to the amount of intermediate water included in the hydrated polymers. The composition of PBA altered the features of the phase-separated structures observed on the polymer/phosphate-buffered saline interfaces. Microscopically, the denaturation of fibrinogen was observed as the formation of fibrous networks on the interfaces by atomic force microscopy. Fibrinogen adsorption and denaturation were enhanced on the water-rich domains in the phase-separated structures on the non-blood-compatible polymers. This suggested that the excellent blood compatibility of PMEA is caused by the constrained adsorption and denaturation of fibrinogen in water-rich domains, possibly due to the high content of intermediate water in this region. This work provides essential scientific foundations for the design and fabrication of highly functional biomaterials..
41. Masaru Tanaka, Shingo Kobayashi, Daiki Murakami, Fumihiro Aratsu, Aki Kashiwazaki, Takashi Hoshiba, Kazuki Fukushima, Design of Polymeric Biomaterials
The "Intermediate Water Concept", Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20190274, 92, 12, 2043-2057, 2019.01, When biomaterials come into contact with biological fluids, water molecules immediately adsorb onto the surface of the materials. To understand the origin of the crucial roles of water molecules in biological interfaces, it is necessary to relate particular states of hydration water to various physicochemical properties of hydrated polymers. Here, advances in the inter-mediate water concept are reviewed. This account provides an overview of the progress made in the design of multi-functional biomedical polymers by controlling the bio-interfacial water states. Using principles of intermediate water, which is common in hydrated biopolymers and only biocompatible synthetic polymers, we found the synthetic methodology to create novel biocompatible polymers moves toward a more high-throughput way..
42. Daiki Murakami, Yuto Segami, Tomoya Ueda, Masaru Tanaka, Control of interfacial structures and anti-platelet adhesion property of blood-compatible random copolymers, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2019.1680930, 2019.01, Fibrinogen adsorption behavior on the blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), non-blood-compatible polymer, poly(n-butyl acrylate) (PBA), and random copolymers of both were examined. Adsorption and denaturation of fibrinogen on the polymers increased as the ratio of PBA increased. The incremental change corresponded to the amount of intermediate water included in the hydrated polymers. The composition of PBA altered the features of the phase-separated structures observed on the polymer/phosphate-buffered saline interfaces. Microscopically, the denaturation of fibrinogen was observed as the formation of fibrous networks on the interfaces by atomic force microscopy. Fibrinogen adsorption and denaturation were enhanced on the water-rich domains in the phase-separated structures on the non-blood-compatible polymers. This suggested that the excellent blood compatibility of PMEA is caused by the constrained adsorption and denaturation of fibrinogen in water-rich domains, possibly due to the high content of intermediate water in this region. This work provides essential scientific foundations for the design and fabrication of highly functional biomaterials..
43. Masaru Tanaka, Shingo Kobayashi, Daiki Murakami, Fumihiro Aratsu, Aki Kashiwazaki, Takashi Hoshiba, Kazuki Fukushima, Design of Polymeric Biomaterials
The "Intermediate Water Concept", Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20190274, 92, 12, 2043-2057, 2019.01, When biomaterials come into contact with biological fluids, water molecules immediately adsorb onto the surface of the materials. To understand the origin of the crucial roles of water molecules in biological interfaces, it is necessary to relate particular states of hydration water to various physicochemical properties of hydrated polymers. Here, advances in the inter-mediate water concept are reviewed. This account provides an overview of the progress made in the design of multi-functional biomedical polymers by controlling the bio-interfacial water states. Using principles of intermediate water, which is common in hydrated biopolymers and only biocompatible synthetic polymers, we found the synthetic methodology to create novel biocompatible polymers moves toward a more high-throughput way..
44. Design of Polymeric Biomaterials: The "Intermediate Water Concept"
© 2019 The Chemical Society of Japan. When biomaterials come into contact with biological fluids, water molecules immediately adsorb onto the surface of the materials. To understand the origin of the crucial roles of water molecules in biological interfaces, it is necessary to relate particular states of hydration water to various physicochemical properties of hydrated polymers. Here, advances in the inter-mediate water concept are reviewed. This account provides an overview of the progress made in the design of multi-functional biomedical polymers by controlling the bio-interfacial water states. Using principles of intermediate water, which is common in hydrated biopolymers and only biocompatible synthetic polymers, we found the synthetic methodology to create novel biocompatible polymers moves toward a more high-throughput way..
45. Wonryung Lee, Shingo Kobayashi, Masase Nagase, Yasutoshi Jimbo, Itsuro Saito, Yusuke Inoue, Tomoyuki Yambe, Masaki Sekino, George G. Malliaras, Tomoyuki Yokota, Masaru Tanaka, Takao Someya, Nonthrombogenic, stretchable, active multielectrode array for electroanatomical mapping, Science Advances, 10.1126/sciadv.aau2426, 4, 10, 2018.10, Science Advances誌 High-precision monitoring of electrophysiological signals with high spatial and temporal resolutions is one of the most important subjects for elucidating physiology functions. Recently, ultraflexible multielectrode arrays (MEAs) have been fabricated to establish conformal contacts with the surface of organs and to measure propagation of electrophysiological signals with high spatial-temporal resolution; however, plastic substrates have high Young's modulus, causing difficulties in creating appropriate stretchability and blood compatibility for applying them on the dynamically moving and surgical bleeding surface of the heart. Here, we have successfully fabricated an active MEA that simultaneously achieves nonthrombogenicity, stretchability, and stability, which allows long-term electrocardiographic (ECG) monitoring of the dynamically moving hearts of rats even with capillary bleeding. Because of the active data readout, the measured ECG signals exhibit a high signal-to-noise ratio of 52 dB. The novel stretchable MEA is carefully designed using state-of-the-art engineering techniques by combining extraordinarily high gain organic electrochemical transistors processed on microgrid substrates and a coating of poly(3-methoxypropyl acrylate), which exhibits significant antithrombotic properties while maintaining excellent ionic conductivity..
46. Wonryung Lee, Shingo Kobayashi, Masase Nagase, Yasutoshi Jimbo, Itsuro Saito, Yusuke Inoue, Tomoyuki Yambe, Masaki Sekino, George G. Malliaras, Tomoyuki Yokota, Masaru Tanaka, Takao Someya, Nonthrombogenic, stretchable, active multielectrode array for electroanatomical mapping, Science Advances, 10.1126/sciadv.aau2426, 4, 10, 2018.10, High-precision monitoring of electrophysiological signals with high spatial and temporal resolutions is one of the most important subjects for elucidating physiology functions. Recently, ultraflexible multielectrode arrays (MEAs) have been fabricated to establish conformal contacts with the surface of organs and to measure propagation of electrophysiological signals with high spatial-temporal resolution; however, plastic substrates have high Young's modulus, causing difficulties in creating appropriate stretchability and blood compatibility for applying them on the dynamically moving and surgical bleeding surface of the heart. Here, we have successfully fabricated an active MEA that simultaneously achieves nonthrombogenicity, stretchability, and stability, which allows long-term electrocardiographic (ECG) monitoring of the dynamically moving hearts of rats even with capillary bleeding. Because of the active data readout, the measured ECG signals exhibit a high signal-to-noise ratio of 52 dB. The novel stretchable MEA is carefully designed using state-of-the-art engineering techniques by combining extraordinarily high gain organic electrochemical transistors processed on microgrid substrates and a coating of poly(3-methoxypropyl acrylate), which exhibits significant antithrombotic properties while maintaining excellent ionic conductivity..
47. W. Lee, S. Kobayashi, M. Nagase, Y. Jimbo, I. Saito, Y. Inoue, T. Yambe, M. Sekino, G. G Malliaras, T. Yokota, M. Tanaka, T. Someya, A Nonthrombogenic, Stretchable, Active Multielectrode Array using Organic Electrochemical Transistors, Science Advances, 10.1126/sciadv.aau2426, 4, 10, eaau2426, 2018.10.
48. Masaru Tanaka, Hydrogel Preparation and Characterisation Derived from Chitosan and Amino Functional Monomers for Biomedical Applications, Journal of Materials Chemistry B, 6, 5115, 2018.08.
49. Masaru Tanaka, Hydrogel Preparation and Characterisation Derived from Chitosan and Amino Functional Monomers for Biomedical Applications, Journal of Materials Chemistry B, 6, 5115, 2018.08.
50. Daiki Murakami, Yoko Kitahara, Shingo Kobayashi, Masaru Tanaka, Thermosensitive Polymer Biocompatibility Based on Interfacial Structure at Biointerface, ACS Biomaterials Science and Engineering, 10.1021/acsbiomaterials.8b00081, 4, 5, 1591-1597, 2018.05, The interfacial structure of a thermosensitive biocompatible polymer, poly[2-(2-methoxyethoxy)ethyl methacrylate] (PMe2MA), at the polymer/phosphate-buffered saline (PBS) interface was investigated by atomic force microscopy. A number of nanometer scale protrusions appeared at 37 °C and disappeared at 22 °C, reversibly. This structural change occurred above the lower critical solution temperature of PMe2MA in PBS (19 °C), indicating that the formation of protrusions was explained by the microphase separation of polymer and water at the interfacial region. The protein adsorption and platelet adhesion onto PMe2MA interface were drastically restrained at 22 °C compared to that at 37 °C. Detachment of NIH3T3 cells accompanied by the dissipation of protrusions on the PMe2MA interface was also demonstrated. These results indicate that the protrusions act as the scaffold for the protein adsorption and cell adhesion..
51. Mostafa Mabrouk, Hanan H. Beherei, Shaimaa ElShebiney, Masaru Tanaka, Newly developed controlled release subcutaneous formulation for tramadol hydrochloride, Saudi Pharmaceutical Journal, 10.1016/j.jsps.2018.01.014, 26, 4, 585-592, 2018.05, This study presents a drug delivery system of poly (Ɛ-caprolactone) (PCL) ribbons to optimize the pharmaceutical action of tramadol for the first time according to our knowledge. PCL ribbons were fabricated and loaded with tramadol HCl. Ribbons were prepared by slip casting technique and coated with dipping technique with β-cyclodextrin. The chemical integrity and surface morphology of the ribbons were confirmed using FTIR and SEM coupled with EDX. In addition, thermodynamic behavior of the fabricated ribbons was investigated using DSC/TGA. Tramadol loading into PCL ribbons, biodegradation of ribbons and tramadol release kinetics were studied in PBS.The results revealed that the formulated composition did not affect the chemical integrity of the drug. Furthermore, SEM/EDX confirmed the inclusion of tramadol into the PCL matrix in homogenous distribution pattern without any observation of porous structure. The particle size of loaded tramadol was found to be in the range of (2–4 nm). The formulated composition did not affect the chemical integrity of the drug and should be further investigated for bioavailability. Tramadol exhibited controlled release behavior from PCL ribbons up to 45 days governed mainly by diffusion mechanism. The fabricated ribbons have a great potentiality to be implemented in the long term subcutaneous delivery of tramadol..
52. Mostafa Mabrouk, Hanan H. Beherei, Shaimaa ElShebiney, Masaru Tanaka, Newly developed controlled release subcutaneous formulation for tramadol hydrochloride, Saudi Pharmaceutical Journal, 10.1016/j.jsps.2018.01.014, 26, 4, 585-592, 2018.05, This study presents a drug delivery system of poly (Ɛ-caprolactone) (PCL) ribbons to optimize the pharmaceutical action of tramadol for the first time according to our knowledge. PCL ribbons were fabricated and loaded with tramadol HCl. Ribbons were prepared by slip casting technique and coated with dipping technique with β-cyclodextrin. The chemical integrity and surface morphology of the ribbons were confirmed using FTIR and SEM coupled with EDX. In addition, thermodynamic behavior of the fabricated ribbons was investigated using DSC/TGA. Tramadol loading into PCL ribbons, biodegradation of ribbons and tramadol release kinetics were studied in PBS.The results revealed that the formulated composition did not affect the chemical integrity of the drug. Furthermore, SEM/EDX confirmed the inclusion of tramadol into the PCL matrix in homogenous distribution pattern without any observation of porous structure. The particle size of loaded tramadol was found to be in the range of (2–4 nm). The formulated composition did not affect the chemical integrity of the drug and should be further investigated for bioavailability. Tramadol exhibited controlled release behavior from PCL ribbons up to 45 days governed mainly by diffusion mechanism. The fabricated ribbons have a great potentiality to be implemented in the long term subcutaneous delivery of tramadol..
53. Daiki Murakami, Yoko Kitahara, Shingo Kobayashi, Masaru Tanaka, Thermosensitive Polymer Biocompatibility Based on Interfacial Structure at Biointerface, ACS Biomaterials Science and Engineering, 10.1021/acsbiomaterials.8b00081, 4, 5, 1591-1597, 2018.05, The interfacial structure of a thermosensitive biocompatible polymer, poly[2-(2-methoxyethoxy)ethyl methacrylate] (PMe2MA), at the polymer/phosphate-buffered saline (PBS) interface was investigated by atomic force microscopy. A number of nanometer scale protrusions appeared at 37 °C and disappeared at 22 °C, reversibly. This structural change occurred above the lower critical solution temperature of PMe2MA in PBS (19 °C), indicating that the formation of protrusions was explained by the microphase separation of polymer and water at the interfacial region. The protein adsorption and platelet adhesion onto PMe2MA interface were drastically restrained at 22 °C compared to that at 37 °C. Detachment of NIH3T3 cells accompanied by the dissipation of protrusions on the PMe2MA interface was also demonstrated. These results indicate that the protrusions act as the scaffold for the protein adsorption and cell adhesion..
54. Mostafa Mabrouk, Hanan H. Beherei, Shaimaa ElShebiney, Masaru Tanaka, Newly developed controlled release subcutaneous formulation for tramadol hydrochloride, Saudi Pharmaceutical Journal, 10.1016/j.jsps.2018.01.014, 26, 4, 585-592, 2018.05, This study presents a drug delivery system of poly (Ɛ-caprolactone) (PCL) ribbons to optimize the pharmaceutical action of tramadol for the first time according to our knowledge. PCL ribbons were fabricated and loaded with tramadol HCl. Ribbons were prepared by slip casting technique and coated with dipping technique with β-cyclodextrin. The chemical integrity and surface morphology of the ribbons were confirmed using FTIR and SEM coupled with EDX. In addition, thermodynamic behavior of the fabricated ribbons was investigated using DSC/TGA. Tramadol loading into PCL ribbons, biodegradation of ribbons and tramadol release kinetics were studied in PBS.The results revealed that the formulated composition did not affect the chemical integrity of the drug. Furthermore, SEM/EDX confirmed the inclusion of tramadol into the PCL matrix in homogenous distribution pattern without any observation of porous structure. The particle size of loaded tramadol was found to be in the range of (2–4 nm). The formulated composition did not affect the chemical integrity of the drug and should be further investigated for bioavailability. Tramadol exhibited controlled release behavior from PCL ribbons up to 45 days governed mainly by diffusion mechanism. The fabricated ribbons have a great potentiality to be implemented in the long term subcutaneous delivery of tramadol..
55. Takashi Hoshiba, Kazuhiro Sato, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Chondrocyte shapes and detachment on a thermoresponsive poly(2-methoxyethyl acrylate) analog for the development of new chondrocytes subculture substrate, Chemistry Letters, 10.1246/cl.170889, 47, 1, 107-109, 2018.01, Chondrocyte dedifferentiation during subculture prevents cartilage tissue engineering. The dedifferentiation is generally caused by cell spreading and trypsin treatment. Thus, it is expected that chondrocytes maintain their specific functions when the cells are subcultured on a substrate that can suppress cell spreading and allow the cells to detach without trypsin treatment. Here, we showed that thermoresponsive poly(2-methoxyethyl acrylate) and analogous polymers can be used to suppress cell spreading and detachment without trypsin treatment..
56. Ferdous Khan, Masaru Tanaka, Designing smart biomaterials for tissue engineering, International Journal of Molecular Sciences, 10.3390/ijms19010017, 19, 1, 2018.01, The engineering of human tissues to cure diseases is an interdisciplinary and a very attractive field of research both in academia and the biotechnology industrial sector. Three-dimensional (3D) biomaterial scaffolds can play a critical role in the development of new tissue morphogenesis via interacting with human cells. Although simple polymeric biomaterials can provide mechanical and physical properties required for tissue development, insufficient biomimetic property and lack of interactions with human progenitor cells remain problematic for the promotion of functional tissue formation. Therefore, the developments of advanced functional biomaterials that respond to stimulus could be the next choice to generate smart 3D biomimetic scaffolds, actively interacting with human stem cells and progenitors along with structural integrity to form functional tissue within a short period. To date, smart biomaterials are designed to interact with biological systems for a wide range of biomedical applications, from the delivery of bioactive molecules and cell adhesion mediators to cellular functioning for the engineering of functional tissues to treat diseases..
57. Ferdous Khan, Fumihiro Aratsu, Shingo Kobayashi, Masaru Tanaka, A simple strategy for robust preparation and characterisation of hydrogels derived from chitosan and amino functional monomers for biomedical applications, Journal of Materials Chemistry B, 10.1039/c8tb00865e, 6, 31, 5115-5129, 2018.01, Molecular interactions of amino functional (AF) monomers with chitosan (CS) lead to the formation of external stimuli responsive hydrogels (HGs). These have the potential to produce biomaterials with novel properties by a simple blending approach. Six independent AF monomers such as diethylenetriamine (DETA), bis(3-aminopropyl)amine (BAPA), 3,3′-diamino-N-methyldipropyleamine (DAMPA), hexamethylenediamine (HMDA), N,N-dimethylethylamine (DMEA) and diethylamine (DEA) with distinct functional groups and chain lengths were designed to form stable HGs at physiological pH. Such AF monomers are able to form HGs within a short time (in the range from 10 to 19 seconds) by physically interacting with CS. This is an alternative to the covalently crosslinking reaction process, providing cost effective HG biomaterials. HG complexes were characterized by rheometry, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The interaction between AF monomers and the CS polymer has been discussed and the results have been confirmed by FTIR analysis. The storage modulus (G′), loss modulus (G′′) and complex viscosity (η∗) were evaluated for all HGs using a rheometer, and the ratios of CS and the particular AF monomer were optimized for stable HG formation. The swelling ratio was evaluated using a simple method and was found to be directly related to the structure of the AF monomer, pH and temperature. These HGs were utilised for encapsulation, and the release of active molecules (e.g., reactive red 120 (RR120) as a model compound) was measured at low pH 5.5, physiological pH 7.4 and high pH 9.5. The cell viability and cellular compatibility of the HGs were evaluated in vitro cell culture, demonstrating that all the five different types of HGs support cellular compatibility, attachment and growth. The physical mixing of AF monomers with CS is expedited for the development of new bespoke economically viable biomaterials..
58. Tomoya Ueda, Daiki Murakami, Masaru Tanaka, Analysis of interaction between interfacial structure and fibrinogen at blood-compatible polymer/water interface, Frontiers in Chemistry, 10.3389/fchem.2018.00542, 6, 2018.01, The correlation between the interfacial structure and protein adsorption at a polymer/water interface was investigated. Poly(2-methoxyethyl acrylate)(PMEA), which is one of the best blood compatible polymers available, was employed. Nanometer-scale structures generated through the phase separation of polymer and water were observed at the PMEA/phosphate buffered saline interface. The interaction between the interfacial structures and fibrinogen (FNG) was measured using atomic force microscopy. Attraction was observed in the polymer-rich domains as well as in the non-blood compatible polymer. In contrast, no attractive interactions were observed, and only a repulsion occurred in the water-rich domains. The non-adsorption of FNG into the water rich domains was also clarified through topographic and phase image analyses. Furthermore, the FNG molecules adsorbed on the surface of PMEA were easily desorbed, even in the polymer-rich domains. Water molecules in the water-rich domains are anticipated to be the dominant factor in preventing FNG adsorption and thrombogenesis on a PMEA interface..
59. Masaru Tanaka, Design of multifunctional soft biomaterials
Based on the intermediate water concept, New Polymeric Materials Based on Element-Blocks, 10.1007/978-981-13-2889-3_23, 423-432, 2018.01, There are numerous parameters of polymeric biomaterials that can affect the protein adsorption and cell adhesion. The mechanisms responsible for the polymer/protein/cell interactions at the molecular level have not been clearly demonstrated, although many experimental and theoretical efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the protein and cell response to contact with polymers. This chapter focuses on the interfacial water at the polymer/protein/cell interfaces and specific water structure in hydrated biopolymers and bio-inspired water in hydrated synthetic polymers. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for medical devices and provides an overview of the progress made in the design of multifunctional element-block polymers by controlling the bio-inspired water structure through precision polymer synthesis..
60. Ferdous Khan, Fumihiro Aratsu, Shingo Kobayashi, Masaru Tanaka, A simple strategy for robust preparation and characterisation of hydrogels derived from chitosan and amino functional monomers for biomedical applications, Journal of Materials Chemistry B, 10.1039/c8tb00865e, 6, 31, 5115-5129, 2018.01, Molecular interactions of amino functional (AF) monomers with chitosan (CS) lead to the formation of external stimuli responsive hydrogels (HGs). These have the potential to produce biomaterials with novel properties by a simple blending approach. Six independent AF monomers such as diethylenetriamine (DETA), bis(3-aminopropyl)amine (BAPA), 3,3′-diamino-N-methyldipropyleamine (DAMPA), hexamethylenediamine (HMDA), N,N-dimethylethylamine (DMEA) and diethylamine (DEA) with distinct functional groups and chain lengths were designed to form stable HGs at physiological pH. Such AF monomers are able to form HGs within a short time (in the range from 10 to 19 seconds) by physically interacting with CS. This is an alternative to the covalently crosslinking reaction process, providing cost effective HG biomaterials. HG complexes were characterized by rheometry, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The interaction between AF monomers and the CS polymer has been discussed and the results have been confirmed by FTIR analysis. The storage modulus (G′), loss modulus (G′′) and complex viscosity (η∗) were evaluated for all HGs using a rheometer, and the ratios of CS and the particular AF monomer were optimized for stable HG formation. The swelling ratio was evaluated using a simple method and was found to be directly related to the structure of the AF monomer, pH and temperature. These HGs were utilised for encapsulation, and the release of active molecules (e.g., reactive red 120 (RR120) as a model compound) was measured at low pH 5.5, physiological pH 7.4 and high pH 9.5. The cell viability and cellular compatibility of the HGs were evaluated in vitro cell culture, demonstrating that all the five different types of HGs support cellular compatibility, attachment and growth. The physical mixing of AF monomers with CS is expedited for the development of new bespoke economically viable biomaterials..
61. Tomoya Ueda, Daiki Murakami, Masaru Tanaka, Analysis of interaction between interfacial structure and fibrinogen at blood-compatible polymer/water interface, Frontiers in Chemistry, 10.3389/fchem.2018.00542, 6, 2018.01, The correlation between the interfacial structure and protein adsorption at a polymer/water interface was investigated. Poly(2-methoxyethyl acrylate)(PMEA), which is one of the best blood compatible polymers available, was employed. Nanometer-scale structures generated through the phase separation of polymer and water were observed at the PMEA/phosphate buffered saline interface. The interaction between the interfacial structures and fibrinogen (FNG) was measured using atomic force microscopy. Attraction was observed in the polymer-rich domains as well as in the non-blood compatible polymer. In contrast, no attractive interactions were observed, and only a repulsion occurred in the water-rich domains. The non-adsorption of FNG into the water rich domains was also clarified through topographic and phase image analyses. Furthermore, the FNG molecules adsorbed on the surface of PMEA were easily desorbed, even in the polymer-rich domains. Water molecules in the water-rich domains are anticipated to be the dominant factor in preventing FNG adsorption and thrombogenesis on a PMEA interface..
62. Takashi Hoshiba, Kazuhiro Sato, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Chondrocyte shapes and detachment on a thermoresponsive poly(2-methoxyethyl acrylate) analog for the development of new chondrocytes subculture substrate, Chemistry Letters, 10.1246/cl.170889, 47, 1, 107-109, 2018.01, Chondrocyte dedifferentiation during subculture prevents cartilage tissue engineering. The dedifferentiation is generally caused by cell spreading and trypsin treatment. Thus, it is expected that chondrocytes maintain their specific functions when the cells are subcultured on a substrate that can suppress cell spreading and allow the cells to detach without trypsin treatment. Here, we showed that thermoresponsive poly(2-methoxyethyl acrylate) and analogous polymers can be used to suppress cell spreading and detachment without trypsin treatment..
63. Masaru Tanaka, Design of multifunctional soft biomaterials
Based on the intermediate water concept, New Polymeric Materials Based on Element-Blocks, 10.1007/978-981-13-2889-3_23, 423-432, 2018.01, There are numerous parameters of polymeric biomaterials that can affect the protein adsorption and cell adhesion. The mechanisms responsible for the polymer/protein/cell interactions at the molecular level have not been clearly demonstrated, although many experimental and theoretical efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the protein and cell response to contact with polymers. This chapter focuses on the interfacial water at the polymer/protein/cell interfaces and specific water structure in hydrated biopolymers and bio-inspired water in hydrated synthetic polymers. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for medical devices and provides an overview of the progress made in the design of multifunctional element-block polymers by controlling the bio-inspired water structure through precision polymer synthesis..
64. Ferdous Khan, Masaru Tanaka, Designing smart biomaterials for tissue engineering, International journal of molecular sciences, 10.3390/ijms19010017, 19, 1, 2018.01, The engineering of human tissues to cure diseases is an interdisciplinary and a very attractive field of research both in academia and the biotechnology industrial sector. Three-dimensional (3D) biomaterial scaffolds can play a critical role in the development of new tissue morphogenesis via interacting with human cells. Although simple polymeric biomaterials can provide mechanical and physical properties required for tissue development, insufficient biomimetic property and lack of interactions with human progenitor cells remain problematic for the promotion of functional tissue formation. Therefore, the developments of advanced functional biomaterials that respond to stimulus could be the next choice to generate smart 3D biomimetic scaffolds, actively interacting with human stem cells and progenitors along with structural integrity to form functional tissue within a short period. To date, smart biomaterials are designed to interact with biological systems for a wide range of biomedical applications, from the delivery of bioactive molecules and cell adhesion mediators to cellular functioning for the engineering of functional tissues to treat diseases..
65. Ferdous Khan, Fumihiro Aratsu, Shingo Kobayashi, Masaru Tanaka, A simple strategy for robust preparation and characterisation of hydrogels derived from chitosan and amino functional monomers for biomedical applications, Journal of Materials Chemistry B, 10.1039/c8tb00865e, 6, 31, 5115-5129, 2018.01, Molecular interactions of amino functional (AF) monomers with chitosan (CS) lead to the formation of external stimuli responsive hydrogels (HGs). These have the potential to produce biomaterials with novel properties by a simple blending approach. Six independent AF monomers such as diethylenetriamine (DETA), bis(3-aminopropyl)amine (BAPA), 3,3′-diamino-N-methyldipropyleamine (DAMPA), hexamethylenediamine (HMDA), N,N-dimethylethylamine (DMEA) and diethylamine (DEA) with distinct functional groups and chain lengths were designed to form stable HGs at physiological pH. Such AF monomers are able to form HGs within a short time (in the range from 10 to 19 seconds) by physically interacting with CS. This is an alternative to the covalently crosslinking reaction process, providing cost effective HG biomaterials. HG complexes were characterized by rheometry, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The interaction between AF monomers and the CS polymer has been discussed and the results have been confirmed by FTIR analysis. The storage modulus (G′), loss modulus (G′′) and complex viscosity (η∗) were evaluated for all HGs using a rheometer, and the ratios of CS and the particular AF monomer were optimized for stable HG formation. The swelling ratio was evaluated using a simple method and was found to be directly related to the structure of the AF monomer, pH and temperature. These HGs were utilised for encapsulation, and the release of active molecules (e.g., reactive red 120 (RR120) as a model compound) was measured at low pH 5.5, physiological pH 7.4 and high pH 9.5. The cell viability and cellular compatibility of the HGs were evaluated in vitro cell culture, demonstrating that all the five different types of HGs support cellular compatibility, attachment and growth. The physical mixing of AF monomers with CS is expedited for the development of new bespoke economically viable biomaterials..
66. Tomoya Ueda, Daiki Murakami, Masaru Tanaka, Analysis of interaction between interfacial structure and fibrinogen at blood-compatible polymer/water interface, Frontiers in Chemistry, 10.3389/fchem.2018.00542, 6, 2018.01, The correlation between the interfacial structure and protein adsorption at a polymer/water interface was investigated. Poly(2-methoxyethyl acrylate)(PMEA), which is one of the best blood compatible polymers available, was employed. Nanometer-scale structures generated through the phase separation of polymer and water were observed at the PMEA/phosphate buffered saline interface. The interaction between the interfacial structures and fibrinogen (FNG) was measured using atomic force microscopy. Attraction was observed in the polymer-rich domains as well as in the non-blood compatible polymer. In contrast, no attractive interactions were observed, and only a repulsion occurred in the water-rich domains. The non-adsorption of FNG into the water rich domains was also clarified through topographic and phase image analyses. Furthermore, the FNG molecules adsorbed on the surface of PMEA were easily desorbed, even in the polymer-rich domains. Water molecules in the water-rich domains are anticipated to be the dominant factor in preventing FNG adsorption and thrombogenesis on a PMEA interface..
67. Takashi Hoshiba, Kazuhiro Sato, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Chondrocyte shapes and detachment on a thermoresponsive poly(2-methoxyethyl acrylate) analog for the development of new chondrocytes subculture substrate, Chemistry Letters, 10.1246/cl.170889, 47, 1, 107-109, 2018.01, Chondrocyte dedifferentiation during subculture prevents cartilage tissue engineering. The dedifferentiation is generally caused by cell spreading and trypsin treatment. Thus, it is expected that chondrocytes maintain their specific functions when the cells are subcultured on a substrate that can suppress cell spreading and allow the cells to detach without trypsin treatment. Here, we showed that thermoresponsive poly(2-methoxyethyl acrylate) and analogous polymers can be used to suppress cell spreading and detachment without trypsin treatment..
68. Masaru Tanaka, Design of multifunctional soft biomaterials
Based on the intermediate water concept, New Polymeric Materials Based on Element-Blocks, 10.1007/978-981-13-2889-3_23, 423-432, 2018.01, There are numerous parameters of polymeric biomaterials that can affect the protein adsorption and cell adhesion. The mechanisms responsible for the polymer/protein/cell interactions at the molecular level have not been clearly demonstrated, although many experimental and theoretical efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the protein and cell response to contact with polymers. This chapter focuses on the interfacial water at the polymer/protein/cell interfaces and specific water structure in hydrated biopolymers and bio-inspired water in hydrated synthetic polymers. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for medical devices and provides an overview of the progress made in the design of multifunctional element-block polymers by controlling the bio-inspired water structure through precision polymer synthesis..
69. Ferdous Khan, Masaru Tanaka, Designing smart biomaterials for tissue engineering, International journal of molecular sciences, 10.3390/ijms19010017, 19, 1, 2018.01, The engineering of human tissues to cure diseases is an interdisciplinary and a very attractive field of research both in academia and the biotechnology industrial sector. Three-dimensional (3D) biomaterial scaffolds can play a critical role in the development of new tissue morphogenesis via interacting with human cells. Although simple polymeric biomaterials can provide mechanical and physical properties required for tissue development, insufficient biomimetic property and lack of interactions with human progenitor cells remain problematic for the promotion of functional tissue formation. Therefore, the developments of advanced functional biomaterials that respond to stimulus could be the next choice to generate smart 3D biomimetic scaffolds, actively interacting with human stem cells and progenitors along with structural integrity to form functional tissue within a short period. To date, smart biomaterials are designed to interact with biological systems for a wide range of biomedical applications, from the delivery of bioactive molecules and cell adhesion mediators to cellular functioning for the engineering of functional tissues to treat diseases..
70. Ferdous Khan, Masaru Tanaka, Designing smart biomaterials for tissue engineering, International Journal of Molecular Sciences, 10.3390/ijms19010017, 19, 1, 2018.01, The engineering of human tissues to cure diseases is an interdisciplinary and a very attractive field of research both in academia and the biotechnology industrial sector. Three-dimensional (3D) biomaterial scaffolds can play a critical role in the development of new tissue morphogenesis via interacting with human cells. Although simple polymeric biomaterials can provide mechanical and physical properties required for tissue development, insufficient biomimetic property and lack of interactions with human progenitor cells remain problematic for the promotion of functional tissue formation. Therefore, the developments of advanced functional biomaterials that respond to stimulus could be the next choice to generate smart 3D biomimetic scaffolds, actively interacting with human stem cells and progenitors along with structural integrity to form functional tissue within a short period. To date, smart biomaterials are designed to interact with biological systems for a wide range of biomedical applications, from the delivery of bioactive molecules and cell adhesion mediators to cellular functioning for the engineering of functional tissues to treat diseases..
71. Takashi Hoshiba, Hiroka Maruyama, Kazuhiro Sato, Chiho Endo, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Maintenance of Cartilaginous Gene Expression of Serially Subcultured Chondrocytes on Poly(2-Methoxyethyl Acrylate) Analogous Polymers, Macromolecular Bioscience, 10.1002/mabi.201700297, 17, 12, 2017.12, Chondrocytes are important for cartilage tissue engineering. However, dedifferentiation during chondrocyte subculture prevents the application of cartilage tissue engineering. Therefore, prevention of this dedifferentiation is required. Here, the possibility of poly(2-methoxyethyl acrylate) (PMEA) and its analogous polymers, poly(tetrahydrofurfuryl acrylate) (PTHFA) and poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (PMe2A), for chondrocyte subculture without dedifferentiation is examined. Chondrocytes spread on PTHFA and polyethylene terephthalate (PET), whereas their spreading is delayed on PMEA and PMe2A. When primary chondrocytes are subcultured on these polymers, the expression levels of cartilaginous genes are higher on PMEA and PMe2A than on PET and PTHFA. Integrin contribution to the initial cell adhesion is lower on PMEA and PMe2A than on PTHFA and PET. This low level of integrin contribution to cell adhesion may cause a delay in cell spreading and the maintenance of cartilaginous gene expression. These results indicate that PMEA and PMe2A may be favorable substrates for chondrocyte subculture and cartilage tissue engineering..
72. Shingo Kobayashi, Miyuki Wakui, Yukihisa Iwata, Masaru Tanaka, Poly(ω-methoxyalkyl acrylate)s
Nonthrombogenic Polymer Family with Tunable Protein Adsorption, Biomacromolecules, 10.1021/acs.biomac.7b01247, 18, 12, 4214-4223, 2017.12, A series of polyacrylates with different n-alkyl side chain lengths (1 to 6, and 12 carbons) and a ω-methoxy terminal group (poly(ω-methoxyalkyl acrylate): PMCxA) were prepared to study their nonthrombogenicity using human platelet adhesion, micro bicinchoninic acid (micro BCA) protein assay, and enzyme-linked immunosorbent assay (ELISA) tests. In all cases, human platelet adhesion was suppressed on the PMCxA-coated substrates, and the number of human platelets adhered to the PMC3A (poly(3-methoxypropyl acrylate))-coated surface was comparable to that of commercialized nonthrombogenic coating agent poly(2-methoxyethyl acrylate) (PMEA, equal to PMC2A). The amount of protein adsorbed onto the PMCxA was investigated by micro BCA using bovine serum albumin (BSA) and human fibrinogen (hFbn), revealing that PMC3A exhibited significantly high resistance to nonspecific BSA adsorption. Additionally, the amount of hFbn adsorbed onto the PMC3A was suppressed to the same extent as PMEA. The exposure degree of platelet adhesion sites in adsorbed hFbn was evaluated using an ELISA test, and the degree on the PMCxA with three to six methylene carbons was comparable to the PMEA. The hydration water structure in the hydrated PMCxA was also characterized using differential scanning calorimetry (DSC). The amount of intermediate water, which is the hydration water molecules that moderately interact with the polymer matrix, was maximum in the PMEA with two methylene run lengths, whereas the amount decreased by increasing the number of methyelnes in the side chain. The amount of adsorbed protein increased with a decrease in the amount of intermediate water, suggesting that the protein adsorption amount is tunable by simply changing the number of methylene carbons in the side chain. The present study revealed that poly(ω-methoxyalkyl acrylate)s are useful for blood-contacting medical devices, and PMC3A is the best mode of PMCxA to apply as an antiprotein adsorption coating agent..
73. Takashi Hoshiba, Hiroka Maruyama, Kazuhiro Sato, Chiho Endo, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Maintenance of Cartilaginous Gene Expression of Serially Subcultured Chondrocytes on Poly(2-Methoxyethyl Acrylate) Analogous Polymers, Macromolecular Bioscience, 10.1002/mabi.201700297, 17, 12, 2017.12, Chondrocytes are important for cartilage tissue engineering. However, dedifferentiation during chondrocyte subculture prevents the application of cartilage tissue engineering. Therefore, prevention of this dedifferentiation is required. Here, the possibility of poly(2-methoxyethyl acrylate) (PMEA) and its analogous polymers, poly(tetrahydrofurfuryl acrylate) (PTHFA) and poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (PMe2A), for chondrocyte subculture without dedifferentiation is examined. Chondrocytes spread on PTHFA and polyethylene terephthalate (PET), whereas their spreading is delayed on PMEA and PMe2A. When primary chondrocytes are subcultured on these polymers, the expression levels of cartilaginous genes are higher on PMEA and PMe2A than on PET and PTHFA. Integrin contribution to the initial cell adhesion is lower on PMEA and PMe2A than on PTHFA and PET. This low level of integrin contribution to cell adhesion may cause a delay in cell spreading and the maintenance of cartilaginous gene expression. These results indicate that PMEA and PMe2A may be favorable substrates for chondrocyte subculture and cartilage tissue engineering..
74. Shingo Kobayashi, Miyuki Wakui, Yukihisa Iwata, Masaru Tanaka, Poly(ω-methoxyalkyl acrylate)s
Nonthrombogenic Polymer Family with Tunable Protein Adsorption, Biomacromolecules, 10.1021/acs.biomac.7b01247, 18, 12, 4214-4223, 2017.12, A series of polyacrylates with different n-alkyl side chain lengths (1 to 6, and 12 carbons) and a ω-methoxy terminal group (poly(ω-methoxyalkyl acrylate): PMCxA) were prepared to study their nonthrombogenicity using human platelet adhesion, micro bicinchoninic acid (micro BCA) protein assay, and enzyme-linked immunosorbent assay (ELISA) tests. In all cases, human platelet adhesion was suppressed on the PMCxA-coated substrates, and the number of human platelets adhered to the PMC3A (poly(3-methoxypropyl acrylate))-coated surface was comparable to that of commercialized nonthrombogenic coating agent poly(2-methoxyethyl acrylate) (PMEA, equal to PMC2A). The amount of protein adsorbed onto the PMCxA was investigated by micro BCA using bovine serum albumin (BSA) and human fibrinogen (hFbn), revealing that PMC3A exhibited significantly high resistance to nonspecific BSA adsorption. Additionally, the amount of hFbn adsorbed onto the PMC3A was suppressed to the same extent as PMEA. The exposure degree of platelet adhesion sites in adsorbed hFbn was evaluated using an ELISA test, and the degree on the PMCxA with three to six methylene carbons was comparable to the PMEA. The hydration water structure in the hydrated PMCxA was also characterized using differential scanning calorimetry (DSC). The amount of intermediate water, which is the hydration water molecules that moderately interact with the polymer matrix, was maximum in the PMEA with two methylene run lengths, whereas the amount decreased by increasing the number of methyelnes in the side chain. The amount of adsorbed protein increased with a decrease in the amount of intermediate water, suggesting that the protein adsorption amount is tunable by simply changing the number of methylene carbons in the side chain. The present study revealed that poly(ω-methoxyalkyl acrylate)s are useful for blood-contacting medical devices, and PMC3A is the best mode of PMCxA to apply as an antiprotein adsorption coating agent..
75. Takashi Hoshiba, Hiroka Maruyama, Kazuhiro Sato, Chiho Endo, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Maintenance of Cartilaginous Gene Expression of Serially Subcultured Chondrocytes on Poly(2-Methoxyethyl Acrylate) Analogous Polymers, Macromolecular Bioscience, 10.1002/mabi.201700297, 17, 12, 2017.12, Chondrocytes are important for cartilage tissue engineering. However, dedifferentiation during chondrocyte subculture prevents the application of cartilage tissue engineering. Therefore, prevention of this dedifferentiation is required. Here, the possibility of poly(2-methoxyethyl acrylate) (PMEA) and its analogous polymers, poly(tetrahydrofurfuryl acrylate) (PTHFA) and poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (PMe2A), for chondrocyte subculture without dedifferentiation is examined. Chondrocytes spread on PTHFA and polyethylene terephthalate (PET), whereas their spreading is delayed on PMEA and PMe2A. When primary chondrocytes are subcultured on these polymers, the expression levels of cartilaginous genes are higher on PMEA and PMe2A than on PET and PTHFA. Integrin contribution to the initial cell adhesion is lower on PMEA and PMe2A than on PTHFA and PET. This low level of integrin contribution to cell adhesion may cause a delay in cell spreading and the maintenance of cartilaginous gene expression. These results indicate that PMEA and PMe2A may be favorable substrates for chondrocyte subculture and cartilage tissue engineering..
76. Shingo Kobayashi, Miyuki Wakui, Yukihisa Iwata, Masaru Tanaka, Poly(ω-methoxyalkyl acrylate)s
Nonthrombogenic Polymer Family with Tunable Protein Adsorption, Biomacromolecules, 10.1021/acs.biomac.7b01247, 18, 12, 4214-4223, 2017.12, A series of polyacrylates with different n-alkyl side chain lengths (1 to 6, and 12 carbons) and a ω-methoxy terminal group (poly(ω-methoxyalkyl acrylate): PMCxA) were prepared to study their nonthrombogenicity using human platelet adhesion, micro bicinchoninic acid (micro BCA) protein assay, and enzyme-linked immunosorbent assay (ELISA) tests. In all cases, human platelet adhesion was suppressed on the PMCxA-coated substrates, and the number of human platelets adhered to the PMC3A (poly(3-methoxypropyl acrylate))-coated surface was comparable to that of commercialized nonthrombogenic coating agent poly(2-methoxyethyl acrylate) (PMEA, equal to PMC2A). The amount of protein adsorbed onto the PMCxA was investigated by micro BCA using bovine serum albumin (BSA) and human fibrinogen (hFbn), revealing that PMC3A exhibited significantly high resistance to nonspecific BSA adsorption. Additionally, the amount of hFbn adsorbed onto the PMC3A was suppressed to the same extent as PMEA. The exposure degree of platelet adhesion sites in adsorbed hFbn was evaluated using an ELISA test, and the degree on the PMCxA with three to six methylene carbons was comparable to the PMEA. The hydration water structure in the hydrated PMCxA was also characterized using differential scanning calorimetry (DSC). The amount of intermediate water, which is the hydration water molecules that moderately interact with the polymer matrix, was maximum in the PMEA with two methylene run lengths, whereas the amount decreased by increasing the number of methyelnes in the side chain. The amount of adsorbed protein increased with a decrease in the amount of intermediate water, suggesting that the protein adsorption amount is tunable by simply changing the number of methylene carbons in the side chain. The present study revealed that poly(ω-methoxyalkyl acrylate)s are useful for blood-contacting medical devices, and PMC3A is the best mode of PMCxA to apply as an antiprotein adsorption coating agent..
77. Takashi Hoshiba, Hiroka Maruyama, Kazuhiro Sato, Chiho Endo, Naoki Kawazoe, Guoping Chen, Masaru Tanaka, Maintenance of Cartilaginous Gene Expression of Serially Subcultured Chondrocytes on Poly(2-Methoxyethyl Acrylate) Analogous Polymers, MACROMOLECULAR BIOSCIENCE, 10.1002/mabi.201700304, 17, 12, 2017.12, Chondrocytes are important for cartilage tissue engineering. However, dedifferentiation during chondrocyte subculture prevents the application of cartilage tissue engineering. Therefore, prevention of this dedifferentiation is required. Here, the possibility of poly(2-methoxyethyl acrylate) (PMEA) and its analogous polymers, poly(tetrahydrofurfuryl acrylate) (PTHFA) and poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (PMe2A), for chondrocyte subculture without dedifferentiation is examined. Chondrocytes spread on PTHFA and polyethylene terephthalate (PET), whereas their spreading is delayed on PMEA and PMe2A. When primary chondrocytes are subcultured on these polymers, the expression levels of cartilaginous genes are higher on PMEA and PMe2A than on PET and PTHFA. Integrin contribution to the initial cell adhesion is lower on PMEA and PMe2A than on PTHFA and PET. This low level of integrin contribution to cell adhesion may cause a delay in cell spreading and the maintenance of cartilaginous gene expression. These results indicate that PMEA and PMe2A may be favorable substrates for chondrocyte subculture and cartilage tissue engineering..
78. Kobayashi S, Wakui M, Iwata Y, Tanaka M, Poly(ω-methoxyalkyl acrylate)s: Nonthrombogenic Polymer Family with Tunable Protein Adsorption, Biomacromolecules, 10.1021/acs.biomac.7b01247, 18, 12, 4214-4223, 2017.12.
79. Kazuki Fukushima, Yuto Inoue, Yuta Haga, Takayuki Ota, Kota Honda, Chikako Sato, Masaru Tanaka, Monoether-Tagged Biodegradable Polycarbonate Preventing Platelet Adhesion and Demonstrating Vascular Cell Adhesion
A Promising Material for Resorbable Vascular Grafts and Stents, Biomacromolecules, 10.1021/acs.biomac.7b01210, 18, 11, 3834-3843, 2017.11, We developed a biodegradable polycarbonate that demonstrates antithrombogenicity and vascular cell adhesion via organocatalytic ring-opening polymerization of a trimethylene carbonate (TMC) analogue bearing a methoxy group. The monoether-tagged polycarbonate demonstrates a platelet adhesion property that is 93 and 89% lower than those of poly(ethylene terephthalate) and polyTMC, respectively. In contrast, vascular cell adhesion properties of the polycarbonate are comparable to those controls, indicating a potential for selective cell adhesion properties. This difference in the cell adhesion property is well associated with surface hydration, which affects protein adsorption and denaturation. Fibrinogen is slightly denatured on the monoether-tagged polycarbonate, whereas fibronectin is highly activated to expose the RGD motif for favorable vascular cell adhesion. The surface hydration, mainly induced by the methoxy side chain, also contributes to slowing the enzymatic degradation. Consequently, the polycarbonate exhibits decent blood compatibility, vascular cell adhesion properties, and biodegradability, which is promising for applications in resorbable vascular grafts and stents..
80. Kazuki Fukushima, Yuto Inoue, Yuta Haga, Takayuki Ota, Kota Honda, Chikako Sato, Masaru Tanaka, Monoether-Tagged Biodegradable Polycarbonate Preventing Platelet Adhesion and Demonstrating Vascular Cell Adhesion
A Promising Material for Resorbable Vascular Grafts and Stents, Biomacromolecules, 10.1021/acs.biomac.7b01210, 18, 11, 3834-3843, 2017.11, We developed a biodegradable polycarbonate that demonstrates antithrombogenicity and vascular cell adhesion via organocatalytic ring-opening polymerization of a trimethylene carbonate (TMC) analogue bearing a methoxy group. The monoether-tagged polycarbonate demonstrates a platelet adhesion property that is 93 and 89% lower than those of poly(ethylene terephthalate) and polyTMC, respectively. In contrast, vascular cell adhesion properties of the polycarbonate are comparable to those controls, indicating a potential for selective cell adhesion properties. This difference in the cell adhesion property is well associated with surface hydration, which affects protein adsorption and denaturation. Fibrinogen is slightly denatured on the monoether-tagged polycarbonate, whereas fibronectin is highly activated to expose the RGD motif for favorable vascular cell adhesion. The surface hydration, mainly induced by the methoxy side chain, also contributes to slowing the enzymatic degradation. Consequently, the polycarbonate exhibits decent blood compatibility, vascular cell adhesion properties, and biodegradability, which is promising for applications in resorbable vascular grafts and stents..
81. Kazuki Fukushima, Yuto Inoue, Yuta Haga, Takayuki Ota, Kota Honda, Chikako Sato, Masaru Tanaka, Monoether-Tagged Biodegradable Polycarbonate Preventing Platelet Adhesion and Demonstrating Vascular Cell Adhesion
A Promising Material for Resorbable Vascular Grafts and Stents, Biomacromolecules, 10.1021/acs.biomac.7b01210, 18, 11, 3834-3843, 2017.11, We developed a biodegradable polycarbonate that demonstrates antithrombogenicity and vascular cell adhesion via organocatalytic ring-opening polymerization of a trimethylene carbonate (TMC) analogue bearing a methoxy group. The monoether-tagged polycarbonate demonstrates a platelet adhesion property that is 93 and 89% lower than those of poly(ethylene terephthalate) and polyTMC, respectively. In contrast, vascular cell adhesion properties of the polycarbonate are comparable to those controls, indicating a potential for selective cell adhesion properties. This difference in the cell adhesion property is well associated with surface hydration, which affects protein adsorption and denaturation. Fibrinogen is slightly denatured on the monoether-tagged polycarbonate, whereas fibronectin is highly activated to expose the RGD motif for favorable vascular cell adhesion. The surface hydration, mainly induced by the methoxy side chain, also contributes to slowing the enzymatic degradation. Consequently, the polycarbonate exhibits decent blood compatibility, vascular cell adhesion properties, and biodegradability, which is promising for applications in resorbable vascular grafts and stents..
82. Kazuki Fukushima, Yuto Inoue, Yuta Haga, Takayuki Ota, Kota Honda, Chikako Sato, Masaru Tanaka, Monoether-Tagged Biodegradable Polycarbonate Preventing Platelet Adhesion and Demonstrating Vascular Cell Adhesion: A Promising Material for Resorbable Vascular Grafts and Stents, BIOMACROMOLECULES, 10.1021/acs.biomac.7b01210, 18, 11, 3834-3843, 2017.11, We developed a biodegradable polycarbonate that demonstrates antithrombogenicity and vascular cell adhesion via organocatalytic ring-opening polymerization of a trimethylene carbonate (TMC) analogue bearing a methoxy group. The monoether-tagged polycarbonate demonstrates a platelet adhesion property that is 93 and 89% lower than those of poly(ethylene terephthalate) and polyTMC, respectively. In contrast, vascular cell adhesion properties of the polycarbonate are comparable to those controls, indicating a potential for selective cell adhesion properties. This difference in the cell adhesion property is well associated with surface hydration, which affects protein adsorption and denaturation. Fibrinogen is slightly denatured on the monoether-tagged polycarbonate, whereas fibronectin is highly activated to expose the RGD motif for favorable vascular cell adhesion. The surface hydration, mainly induced by the methoxy side chain, also contributes to slowing the enzymatic degradation. Consequently, the polycarbonate exhibits decent blood compatibility, vascular cell adhesion properties, and biodegradability, which is promising for applications in resorbable vascular grafts and stents..
83. Kazuki Fukushima, Kota Honda, Yuto Inoue, Masaru Tanaka, Synthesis of antithrombotic poly(carbonate-urethane)s through a sequential process of ring-opening polymerization and polyaddition facilitated by organocatalysts, European Polymer Journal, 10.1016/j.eurpolymj.2017.07.001, 95, 728-736, 2017.10, We have first confirmed that an organic acid, diphenyl phosphate (DPP) is effective in a sequential process of ring-opening polymerization (ROP) of a cyclic carbonate and polyaddition with a diisocyanate. More potent triflic acid (TfOH) exhibited higher catalytic activities for both ROP and polyaddition than DPP and pairs of thiourea and basic catalysts such as cyclic amidines and sparteine. However, DPP-catalyzed ROP was more manageable than that using TfOH regarding control over the molar-mass dispersity of the resultant polycarbonates that matters to the final polyurethanes. As a consequence of DPP-catalyzed one-pot synthesis of poly(carbonate-urethane)s, we have obtained segmented polyurethanes comprising a poly(trimethylene carbonate) analog with ether side chains as a soft segment and hexamethylene diisocyanate as a hard segment. Although the whole reaction took a few days, high molecular weight over 50 k was achieved for the resultant polyurethanes whose texture suggested improved physical properties. Nevertheless, the polyuretahnes maintained low platelet adhesion properties. This antithrombotic polyurethane became more promising as a candidate base material for resorbable artificial blood vessels. Furthermore, this sequential synthesis by single organocatalysts enables the efficient production of functionalized poly(carbonate-urethane)s..
84. Kazuki Fukushima, Kota Honda, Yuto Inoue, Masaru Tanaka, Synthesis of antithrombotic poly(carbonate-urethane)s through a sequential process of ring-opening polymerization and polyaddition facilitated by organocatalysts, European Polymer Journal, 10.1016/j.eurpolymj.2017.07.001, 95, 728-736, 2017.10, We have first confirmed that an organic acid, diphenyl phosphate (DPP) is effective in a sequential process of ring-opening polymerization (ROP) of a cyclic carbonate and polyaddition with a diisocyanate. More potent triflic acid (TfOH) exhibited higher catalytic activities for both ROP and polyaddition than DPP and pairs of thiourea and basic catalysts such as cyclic amidines and sparteine. However, DPP-catalyzed ROP was more manageable than that using TfOH regarding control over the molar-mass dispersity of the resultant polycarbonates that matters to the final polyurethanes. As a consequence of DPP-catalyzed one-pot synthesis of poly(carbonate-urethane)s, we have obtained segmented polyurethanes comprising a poly(trimethylene carbonate) analog with ether side chains as a soft segment and hexamethylene diisocyanate as a hard segment. Although the whole reaction took a few days, high molecular weight over 50 k was achieved for the resultant polyurethanes whose texture suggested improved physical properties. Nevertheless, the polyuretahnes maintained low platelet adhesion properties. This antithrombotic polyurethane became more promising as a candidate base material for resorbable artificial blood vessels. Furthermore, this sequential synthesis by single organocatalysts enables the efficient production of functionalized poly(carbonate-urethane)s..
85. Kazuki Fukushima, Kota Honda, Yuto Inoue, Masaru Tanaka, Synthesis of antithrombotic poly(carbonate-urethane)s through a sequential process of ring-opening polymerization and polyaddition facilitated by organocatalysts, European Polymer Journal, 10.1016/j.eurpolymj.2017.07.001, 95, 728-736, 2017.10, We have first confirmed that an organic acid, diphenyl phosphate (DPP) is effective in a sequential process of ring-opening polymerization (ROP) of a cyclic carbonate and polyaddition with a diisocyanate. More potent triflic acid (TfOH) exhibited higher catalytic activities for both ROP and polyaddition than DPP and pairs of thiourea and basic catalysts such as cyclic amidines and sparteine. However, DPP-catalyzed ROP was more manageable than that using TfOH regarding control over the molar-mass dispersity of the resultant polycarbonates that matters to the final polyurethanes. As a consequence of DPP-catalyzed one-pot synthesis of poly(carbonate-urethane)s, we have obtained segmented polyurethanes comprising a poly(trimethylene carbonate) analog with ether side chains as a soft segment and hexamethylene diisocyanate as a hard segment. Although the whole reaction took a few days, high molecular weight over 50 k was achieved for the resultant polyurethanes whose texture suggested improved physical properties. Nevertheless, the polyuretahnes maintained low platelet adhesion properties. This antithrombotic polyurethane became more promising as a candidate base material for resorbable artificial blood vessels. Furthermore, this sequential synthesis by single organocatalysts enables the efficient production of functionalized poly(carbonate-urethane)s..
86. Kazuki Fukushima, Kota Honda, Yuto Inoue, Masaru Tanaka, Synthesis of antithrombotic poly(carbonate-urethane)s through a sequential process of ring-opening polymerization and polyaddition facilitated by organocatalysts, EUROPEAN POLYMER JOURNAL, 10.1016/j.eurpolymj.2017.07.001, 95, 728-736, 2017.10, We have first confirmed that an organic acid, diphenyl phosphate (DPP) is effective in a sequential process of ring-opening polymerization (ROP) of a cyclic carbonate and polyaddition with a diisocyanate. More potent triflic acid (TfOH) exhibited higher catalytic activities for both ROP and polyaddition than DPP and pairs of thiourea and basic catalysts such as cyclic amidines and sparteine. However, DPP-catalyzed ROP was more manageable than that using TfOH regarding control over the molar-mass dispersity of the resultant polycarbonates that matters to the final polyurethanes. As a consequence of DPP-catalyzed one-pot synthesis of poly(carbonateurethane)s, we have obtained segmented polyurethanes comprising a poly(trimethylene carbonate) analog with ether side chains as a soft segment and hexamethylene diisocyanate as a hard segment. Although the whole reaction took a few days, high molecular weight over 50 k was achieved for the resultant polyurethanes whose texture suggested improved physical properties. Nevertheless, the polyuretahnes maintained low platelet adhesion properties. This antithrombotic polyurethane became more promising as a candidate base material for resorbable artificial blood vessels. Furthermore, this sequential synthesis by single organocatalysts enables the efficient production of functionalized poly(carbonate-urethane)s..
87. Takashi Hoshiba, Ayano Yoshihiro, Masaru Tanaka, Evaluation of initial cell adhesion on poly (2-methoxyethyl acrylate) (PMEA) analogous polymers, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2017.1312738, 28, 10-12, 986-999, 2017.08, Cell adhesion is a major concern in biomaterial development. Generally, cells adhere to polymeric substrates via the interaction between integrins and proteins adsorbed on the substrates. Previously, it was reported that poly (2-methoxyethyl acrylate) (PMEA) and its analogous polymers can alter the integrin dependency for cell adhesion. In particular, integrin-independent adhesion was observed on PMEA. However, initial adhesion mechanisms, including integrin-independent adhesion mechanisms, on PMEA are not well characterized. In this study, initial cell adhesion within 10 min was characterized on PMEA analogous polymers. Protein adsorption was suppressed on PMEA compared with tissue culture polystyrene, but the cell adhesion site in adsorbed fibronectin was exposed to the cells similarly. HT-1080 cells adhered on PMEA in a serum medium even in the presence of EDTA, suggesting that the cells adhered via both integrin-dependent and integrin-independent mechanisms. Finally, the cell adhesion force was measured by single-cell force spectroscopy. The cell adhesion force was not changed on PMEA in serum and serum-free media, suggesting that the cells adhered on PMEA directly. In conclusion, the control of protein adsorption is useful for regulating integrin dependency for cell adhesion and following the expression of cell functions regulated by integrins..
88. Taito Sekine, Syifa Asatyas, Chikako Sato, Shigeaki Morita, Masaru Tanaka, Tomohiro Hayashi, Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers
mechanisms underlying the effect of lateral packing density on bioinertness, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2017.1303120, 28, 10-12, 1231-1243, 2017.08, Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water. In addition, the results of SEIRA measurements clearly exhibited that hydrogen bonding states of the interfacial water differ depending on the substrates. We also characterized the bioinertness of these SAMs by protein adsorption tests and adhesion assays of platelet and human umbilical vein endothelial cells. The hydrogen bonding states of the interfacial water and water-induced interaction clearly correlated with the bioinertness of the SAMs, suggesting that the interfacial water plays an important role determining the interaction of the SAMs with biomolecules and cells..
89. Takashi Hoshiba, Ayano Yoshihiro, Masaru Tanaka, Evaluation of initial cell adhesion on poly (2-methoxyethyl acrylate) (PMEA) analogous polymers, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2017.1312738, 28, 10-12, 986-999, 2017.08, Cell adhesion is a major concern in biomaterial development. Generally, cells adhere to polymeric substrates via the interaction between integrins and proteins adsorbed on the substrates. Previously, it was reported that poly (2-methoxyethyl acrylate) (PMEA) and its analogous polymers can alter the integrin dependency for cell adhesion. In particular, integrin-independent adhesion was observed on PMEA. However, initial adhesion mechanisms, including integrin-independent adhesion mechanisms, on PMEA are not well characterized. In this study, initial cell adhesion within 10 min was characterized on PMEA analogous polymers. Protein adsorption was suppressed on PMEA compared with tissue culture polystyrene, but the cell adhesion site in adsorbed fibronectin was exposed to the cells similarly. HT-1080 cells adhered on PMEA in a serum medium even in the presence of EDTA, suggesting that the cells adhered via both integrin-dependent and integrin-independent mechanisms. Finally, the cell adhesion force was measured by single-cell force spectroscopy. The cell adhesion force was not changed on PMEA in serum and serum-free media, suggesting that the cells adhered on PMEA directly. In conclusion, the control of protein adsorption is useful for regulating integrin dependency for cell adhesion and following the expression of cell functions regulated by integrins..
90. Taito Sekine, Syifa Asatyas, Chikako Sato, Shigeaki Morita, Masaru Tanaka, Tomohiro Hayashi, Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers
mechanisms underlying the effect of lateral packing density on bioinertness, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2017.1303120, 28, 10-12, 1231-1243, 2017.08, Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water. In addition, the results of SEIRA measurements clearly exhibited that hydrogen bonding states of the interfacial water differ depending on the substrates. We also characterized the bioinertness of these SAMs by protein adsorption tests and adhesion assays of platelet and human umbilical vein endothelial cells. The hydrogen bonding states of the interfacial water and water-induced interaction clearly correlated with the bioinertness of the SAMs, suggesting that the interfacial water plays an important role determining the interaction of the SAMs with biomolecules and cells..
91. Takashi Hoshiba, Ayano Yoshihiro, Masaru Tanaka, Evaluation of initial cell adhesion on poly (2-methoxyethyl acrylate) (PMEA) analogous polymers, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2017.1312738, 28, 10-12, 986-999, 2017.08, Cell adhesion is a major concern in biomaterial development. Generally, cells adhere to polymeric substrates via the interaction between integrins and proteins adsorbed on the substrates. Previously, it was reported that poly (2-methoxyethyl acrylate) (PMEA) and its analogous polymers can alter the integrin dependency for cell adhesion. In particular, integrin-independent adhesion was observed on PMEA. However, initial adhesion mechanisms, including integrin-independent adhesion mechanisms, on PMEA are not well characterized. In this study, initial cell adhesion within 10 min was characterized on PMEA analogous polymers. Protein adsorption was suppressed on PMEA compared with tissue culture polystyrene, but the cell adhesion site in adsorbed fibronectin was exposed to the cells similarly. HT-1080 cells adhered on PMEA in a serum medium even in the presence of EDTA, suggesting that the cells adhered via both integrin-dependent and integrin-independent mechanisms. Finally, the cell adhesion force was measured by single-cell force spectroscopy. The cell adhesion force was not changed on PMEA in serum and serum-free media, suggesting that the cells adhered on PMEA directly. In conclusion, the control of protein adsorption is useful for regulating integrin dependency for cell adhesion and following the expression of cell functions regulated by integrins..
92. Taito Sekine, Syifa Asatyas, Chikako Sato, Shigeaki Morita, Masaru Tanaka, Tomohiro Hayashi, Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers
mechanisms underlying the effect of lateral packing density on bioinertness, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2017.1303120, 28, 10-12, 1231-1243, 2017.08, Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water. In addition, the results of SEIRA measurements clearly exhibited that hydrogen bonding states of the interfacial water differ depending on the substrates. We also characterized the bioinertness of these SAMs by protein adsorption tests and adhesion assays of platelet and human umbilical vein endothelial cells. The hydrogen bonding states of the interfacial water and water-induced interaction clearly correlated with the bioinertness of the SAMs, suggesting that the interfacial water plays an important role determining the interaction of the SAMs with biomolecules and cells..
93. Yusuke Inoue, Tomoyuki Yokota, Tsuyoshi Sekitani, Akiko Kaneko, Taeseong Woo, Shingo Kobayashi, Tomokazu Shibuya, Masaru Tanaka, Hiroyuki Kosukegawa, Itsuro Saito, Takashi Isoyama, Yusuke Abe, Tomoyuki Yambe, Takao Someya, Masaki Sekino, Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime, Annals of Biomedical Engineering, 10.1007/s10439-016-1781-5, 45, 5, 1352-1364, 2017.05, There are recent reports of hybrid tissue–fabric materials with good performance—high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue–fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat’s body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone..
94. Kazuhiro Sato, Shingo Kobayashi, Asuka Sekishita, Miyuki Wakui, Masaru Tanaka, Synthesis and Thrombogenicity Evaluation of Poly(3-methoxypropionic acid vinyl ester)
A Candidate for Blood-Compatible Polymers, Biomacromolecules, 10.1021/acs.biomac.7b00221, 18, 5, 1609-1616, 2017.05, A poly(vinyl acetate) derivative, poly(3-methoxypropionic acid vinyl ester) (PMePVE), was synthesized to develop a new candidate for blood compatible polymers. The monomer MePVE was synthesized by a simple two-step reaction, and then the MePVE was polymerized via free radical polymerization to obtain PMePVE. Human platelet adhesion tests were performed to evaluate the thrombogenicity, and the platelet adhesion was suppressed on the PMePVE-coated substrate. To determine the expression of the nonthrombogenicity of the PMePVE, the plasma protein adsorption and a conformationally altered state of fibrinogen were analyzed by a microBCA assay and enzyme-linked immunosorbent assay. The adsorption and denaturation of the plasma proteins were inhibited on the PMePVE; thus, PMePVE exhibited blood compatibility. A distinctive hydration water structure in the nonthrombogenic polymer, intermediate water (IW), was observed in the hydrated PMePVE by differential scanning calorimetry analysis. The nonthrombogenicity of PMePVE is considered to be brought about by the presence of IW..
95. Yusuke Inoue, Tomoyuki Yokota, Tsuyoshi Sekitani, Akiko Kaneko, Taeseong Woo, Shingo Kobayashi, Tomokazu Shibuya, Masaru Tanaka, Hiroyuki Kosukegawa, Itsuro Saito, Takashi Isoyama, Yusuke Abe, Tomoyuki Yambe, Takao Someya, Masaki Sekino, Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime, Annals of Biomedical Engineering, 10.1007/s10439-016-1781-5, 45, 5, 1352-1364, 2017.05, There are recent reports of hybrid tissue–fabric materials with good performance—high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue–fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat’s body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone..
96. Kazuhiro Sato, Shingo Kobayashi, Asuka Sekishita, Miyuki Wakui, Masaru Tanaka, Synthesis and Thrombogenicity Evaluation of Poly(3-methoxypropionic acid vinyl ester)
A Candidate for Blood-Compatible Polymers, Biomacromolecules, 10.1021/acs.biomac.7b00221, 18, 5, 1609-1616, 2017.05, A poly(vinyl acetate) derivative, poly(3-methoxypropionic acid vinyl ester) (PMePVE), was synthesized to develop a new candidate for blood compatible polymers. The monomer MePVE was synthesized by a simple two-step reaction, and then the MePVE was polymerized via free radical polymerization to obtain PMePVE. Human platelet adhesion tests were performed to evaluate the thrombogenicity, and the platelet adhesion was suppressed on the PMePVE-coated substrate. To determine the expression of the nonthrombogenicity of the PMePVE, the plasma protein adsorption and a conformationally altered state of fibrinogen were analyzed by a microBCA assay and enzyme-linked immunosorbent assay. The adsorption and denaturation of the plasma proteins were inhibited on the PMePVE; thus, PMePVE exhibited blood compatibility. A distinctive hydration water structure in the nonthrombogenic polymer, intermediate water (IW), was observed in the hydrated PMePVE by differential scanning calorimetry analysis. The nonthrombogenicity of PMePVE is considered to be brought about by the presence of IW..
97. Yusuke Inoue, Tomoyuki Yokota, Tsuyoshi Sekitani, Akiko Kaneko, Taeseong Woo, Shingo Kobayashi, Tomokazu Shibuya, Masaru Tanaka, Hiroyuki Kosukegawa, Itsuro Saito, Takashi Isoyama, Yusuke Abe, Tomoyuki Yambe, Takao Someya, Masaki Sekino, Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime, Annals of Biomedical Engineering, 10.1007/s10439-016-1781-5, 45, 5, 1352-1364, 2017.05, There are recent reports of hybrid tissue–fabric materials with good performance—high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue–fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat’s body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone..
98. Kazuhiro Sato, Shingo Kobayashi, Asuka Sekishita, Miyuki Wakui, Masaru Tanaka, Synthesis and Thrombogenicity Evaluation of Poly(3-methoxypropionic acid vinyl ester)
A Candidate for Blood-Compatible Polymers, Biomacromolecules, 10.1021/acs.biomac.7b00221, 18, 5, 1609-1616, 2017.05, A poly(vinyl acetate) derivative, poly(3-methoxypropionic acid vinyl ester) (PMePVE), was synthesized to develop a new candidate for blood compatible polymers. The monomer MePVE was synthesized by a simple two-step reaction, and then the MePVE was polymerized via free radical polymerization to obtain PMePVE. Human platelet adhesion tests were performed to evaluate the thrombogenicity, and the platelet adhesion was suppressed on the PMePVE-coated substrate. To determine the expression of the nonthrombogenicity of the PMePVE, the plasma protein adsorption and a conformationally altered state of fibrinogen were analyzed by a microBCA assay and enzyme-linked immunosorbent assay. The adsorption and denaturation of the plasma proteins were inhibited on the PMePVE; thus, PMePVE exhibited blood compatibility. A distinctive hydration water structure in the nonthrombogenic polymer, intermediate water (IW), was observed in the hydrated PMePVE by differential scanning calorimetry analysis. The nonthrombogenicity of PMePVE is considered to be brought about by the presence of IW..
99. Yusuke Inoue, Tomoyuki Yokota, Tsuyoshi Sekitani, Akiko Kaneko, Taeseong Woo, Shingo Kobayashi, Tomokazu Shibuya, Masaru Tanaka, Hiroyuki Kosukegawa, Itsuro Saito, Takashi Isoyama, Yusuke Abe, Tomoyuki Yambe, Takao Someya, Masaki Sekino, Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime, ANNALS OF BIOMEDICAL ENGINEERING, 10.1007/s10439-016-1781-5, 45, 5, 1352-1364, 2017.05, There are recent reports of hybrid tissue-fabric materials with good performance-high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue-fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat's body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone..
100. Kazuhiro Sato, Shingo Kobayashi, Asuka Sekishita, Miyuki Wakui, Masaru Tanaka, Synthesis and Thrombogenicity Evaluation of Poly(3-methoxypropionic acid vinyl ester): A Candidate for Blood-Compatible Polymers, BIOMACROMOLECULES, 10.1021/acs.biomac.7b00221, 18, 5, 1609-1616, 2017.05, A poly(vinyl acetate) derivative, poly(3-methoxypropionic acid vinyl ester) (PMePVE), was synthesized to develop a new candidate for blood compatible polymers. The monomer MePVE was synthesized by a simple two-step reaction, and then the MePVE was polymerized via free radical polymerization to obtain PMePVE. Human platelet adhesion tests were performed to evaluate the thrombogenicity, and the platelet adhesion was suppressed on the PMePVE-coated substrate. To determine the expression of the nonthrombogenicity of the PMePVE, the plasma protein adsorption and a conformationally altered state of fibrinogen were analyzed by a microBCA assay and enzyme-linked immunosorbent assay. The adsorption and denaturation of the plasma proteins were inhibited on the PMePVE; thus, PMePVE exhibited blood compatibility. A distinctive hydration water structure in the nonthrombogenic polymer, intermediate water (IW), was observed in the hydrated PMePVE by differential scanning calorimetry analysis. The nonthrombogenicity of PMePVE is considered to be brought about by the presence of IW..
101. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Manabu Inutsuka, Tomoyasu Hirai, Masaru Tanaka, Keiji Tanaka, Dynamics of a bioinert polymer in hydrated states by dielectric relaxation spectroscopy, Physical Chemistry Chemical Physics, 10.1039/c6cp07322k, 19, 2, 1389-1394, 2017.04, The chain dynamics of well-defined poly(2-methoxyethyl acrylate) (PMEA), which has been used in practice as a bioinert coating for heart-lung machines, was examined as a function of water content by dielectric relaxation spectroscopy (DRS). Two relaxation processes observed in both dried and hydrated films were assigned to the segmental motion (α-process) and the relatively smaller scale motion such as the hindered rotation of side chains (β-process). Water molecules adsorbed on PMEA made the α-process faster, meaning that water molecules in PMEA played the role of a plasticizer. Combining the above knowledge with the depth dependence of water content in the PMEA film previously obtained by neutron reflectivity, the segmental dynamics of PMEA at the water interface, which should be crucial to bio-inertness, is discussed. We found that the segmental motion was markedly faster than that in the bulk and almost comparable to the side chain motion..
102. Applications of functionalized biodegradable polymers in tissue engineering and regenerative medicine.
103. Masaru Tanaka, Design Concept of Dialyzer Biomaterials
How to Find Biocompatible Polymers Based on the Biointerfacial Water Structure, Contributions to Nephrology, 10.1159/000451043, 189, 137-143, 2017.01, Background: Although various types of materials have been used widely in dialyzers, most biomaterials lack the desired functional properties to interface with blood and have not been engineered for optimum performance. Therefore, there is increasing demand to develop novel materials to address such problems in the dialysis arena. Numerous parameters of polymeric biomaterials can affect biocompatibility in a controlled manner. The mechanisms responsible for the biocompatibility of polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to try and understand them. Moreover, water interactions have been recognized as fundamental for the blood response to contact with polymers. Summary: We have proposed the 'intermediate water' concept and hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or nonfreezing water on the polymer surface, plays an important role in the biocompatibility of polymers. This chapter provides an overview of the recent experimental progress of biocompatible polymers measured by thermal, spectroscopic, and surface force techniques. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for dialyzers and provides an overview of the progress made in the design of multifunctional biomedical polymers by controlling the biointerfacial water structure through precision polymer synthesis. Key Messages: Intermediate water was found only in hydrated biopolymers (proteins, polysaccharides, and nucleic acids, DNA and RNA) and hydrated biocompatible synthetic polymers. Intermediate water could be one of the main screening factors for the design of appropriate dialyzer materials..
104. Masaru Tanaka, Design Concept of Dialyzer Biomaterials
How to Find Biocompatible Polymers Based on the Biointerfacial Water Structure, Contributions to Nephrology, 10.1159/000451043, 189, 137-143, 2017.01, Background: Although various types of materials have been used widely in dialyzers, most biomaterials lack the desired functional properties to interface with blood and have not been engineered for optimum performance. Therefore, there is increasing demand to develop novel materials to address such problems in the dialysis arena. Numerous parameters of polymeric biomaterials can affect biocompatibility in a controlled manner. The mechanisms responsible for the biocompatibility of polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to try and understand them. Moreover, water interactions have been recognized as fundamental for the blood response to contact with polymers. Summary: We have proposed the 'intermediate water' concept and hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or nonfreezing water on the polymer surface, plays an important role in the biocompatibility of polymers. This chapter provides an overview of the recent experimental progress of biocompatible polymers measured by thermal, spectroscopic, and surface force techniques. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for dialyzers and provides an overview of the progress made in the design of multifunctional biomedical polymers by controlling the biointerfacial water structure through precision polymer synthesis. Key Messages: Intermediate water was found only in hydrated biopolymers (proteins, polysaccharides, and nucleic acids, DNA and RNA) and hydrated biocompatible synthetic polymers. Intermediate water could be one of the main screening factors for the design of appropriate dialyzer materials..
105. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Manabu Inutsuka, Tomoyasu Hirai, Masaru Tanaka, Keiji Tanaka, Dynamics of a bioinert polymer in hydrated states by dielectric relaxation spectroscopy, Physical Chemistry Chemical Physics, 10.1039/c6cp07322k, 19, 2, 1389-1394, 2017.01, The chain dynamics of well-defined poly(2-methoxyethyl acrylate) (PMEA), which has been used in practice as a bioinert coating for heart-lung machines, was examined as a function of water content by dielectric relaxation spectroscopy (DRS). Two relaxation processes observed in both dried and hydrated films were assigned to the segmental motion (α-process) and the relatively smaller scale motion such as the hindered rotation of side chains (β-process). Water molecules adsorbed on PMEA made the α-process faster, meaning that water molecules in PMEA played the role of a plasticizer. Combining the above knowledge with the depth dependence of water content in the PMEA film previously obtained by neutron reflectivity, the segmental dynamics of PMEA at the water interface, which should be crucial to bio-inertness, is discussed. We found that the segmental motion was markedly faster than that in the bulk and almost comparable to the side chain motion..
106. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Manabu Inutsuka, Tomoyasu Hirai, Masaru Tanaka, Keiji Tanaka, Dynamics of a bioinert polymer in hydrated states by dielectric relaxation spectroscopy, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 10.1039/c6cp07322k, 19, 2, 1389-1394, 2017.01, The chain dynamics of well-defined poly(2-methoxyethyl acrylate) (PMEA), which has been used in practice as a bioinert coating for heart-lung machines, was examined as a function of water content by dielectric relaxation spectroscopy (DRS). Two relaxation processes observed in both dried and hydrated films were assigned to the segmental motion (alpha-process) and the relatively smaller scale motion such as the hindered rotation of side chains (beta-process). Water molecules adsorbed on PMEA made the alpha-process faster, meaning that water molecules in PMEA played the role of a plasticizer. Combining the above knowledge with the depth dependence of water content in the PMEA film previously obtained by neutron reflectivity, the segmental dynamics of PMEA at the water interface, which should be crucial to bio-inertness, is discussed. We found that the segmental motion was markedly faster than that in the bulk and almost comparable to the side chain motion..
107. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Manabu Inutsuka, Tomoyasu Hirai, Masaru Tanaka, Keiji Tanaka, Dynamics of a bioinert polymer in hydrated states by dielectric relaxation spectroscopy, Physical Chemistry Chemical Physics, 10.1039/c6cp07322k, 19, 2, 1389-1394, 2017, The chain dynamics of well-defined poly(2-methoxyethyl acrylate) (PMEA), which has been used in practice as a bioinert coating for heart-lung machines, was examined as a function of water content by dielectric relaxation spectroscopy (DRS). Two relaxation processes observed in both dried and hydrated films were assigned to the segmental motion (α-process) and the relatively smaller scale motion such as the hindered rotation of side chains (β-process). Water molecules adsorbed on PMEA made the α-process faster, meaning that water molecules in PMEA played the role of a plasticizer. Combining the above knowledge with the depth dependence of water content in the PMEA film previously obtained by neutron reflectivity, the segmental dynamics of PMEA at the water interface, which should be crucial to bio-inertness, is discussed. We found that the segmental motion was markedly faster than that in the bulk and almost comparable to the side chain motion..
108. Daiki Murakami, Shingo Kobayashi, Masaru Tanaka, Interfacial Structures and Fibrinogen Adsorption at Blood-Compatible Polymer/Water Interfaces, ACS Biomaterials Science and Engineering, 10.1021/acsbiomaterials.6b00415, 2, 12, 2122-2126, 2016.12, The interfacial structures of a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), and several analogues were investigated by atomic force microscopy (AFM). The blood-compatible polymers exhibited nanometer-scale protrusions that spontaneously and homogeneously formed at polymer/water and polymer/phosphate-buffered saline interfaces. AFM observation also revealed that fibrinogen adsorption occurred locally on the protrusions rather than uniformly at the interface, with the regions adjacent to the protrusions apparently preventing the adsorption of fibrinogen. The formation of these interfacial structures may be due to in-plane microphase separation of polymer and water at the interface..
109. Daiki Murakami, Shingo Kobayashi, Masaru Tanaka, Interfacial Structures and Fibrinogen Adsorption at Blood-Compatible Polymer/Water Interfaces, ACS Biomaterials Science and Engineering, 10.1021/acsbiomaterials.6b00415, 2, 12, 2122-2126, 2016.12, The interfacial structures of a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), and several analogues were investigated by atomic force microscopy (AFM). The blood-compatible polymers exhibited nanometer-scale protrusions that spontaneously and homogeneously formed at polymer/water and polymer/phosphate-buffered saline interfaces. AFM observation also revealed that fibrinogen adsorption occurred locally on the protrusions rather than uniformly at the interface, with the regions adjacent to the protrusions apparently preventing the adsorption of fibrinogen. The formation of these interfacial structures may be due to in-plane microphase separation of polymer and water at the interface..
110. Daiki Murakami, Shingo Kobayashi, Masaru Tanaka, Interfacial Structures and Fibrinogen Adsorption at Blood-Compatible Polymer/Water Interfaces, ACS Biomaterials Science and Engineering, 10.1021/acsbiomaterials.6b00415, 2, 12, 2122-2126, 2016.12, The interfacial structures of a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), and several analogues were investigated by atomic force microscopy (AFM). The blood-compatible polymers exhibited nanometer-scale protrusions that spontaneously and homogeneously formed at polymer/water and polymer/phosphate-buffered saline interfaces. AFM observation also revealed that fibrinogen adsorption occurred locally on the protrusions rather than uniformly at the interface, with the regions adjacent to the protrusions apparently preventing the adsorption of fibrinogen. The formation of these interfacial structures may be due to in-plane microphase separation of polymer and water at the interface..
111. Daiki Murakami, Shingo Kobayashi, Masaru Tanaka, Interfacial Structures and Fibrinogen Adsorption at Blood Compatible Polymer/Water Interfaces, ACS BIOMATERIALS SCIENCE & ENGINEERING, 10.1021/acsbiomaterials.6b00415, 2, 12, 2122-2126, 2016.12, The interfacial structures of a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), and several analogues were investigated by atomic force microscopy (AFM). The blood-compatible polymers exhibited nano meter-scale protrusions that spontaneously and homogeneously formed at polymer/water and polymer/phosphatebuffered saline interfaces. AFM observation also revealed that fibrinogen adsorption occurred locally on the protrusions rather than uniformly at the interface, with the regions adjacent to the protrusions apparently preventing the adsorption of fibrinogen. The formation of these interfacial structures may be due to in-plane microphase separation of polymer and water at the interface..
112. Andere Basterretxea, Yuta Haga, Ana Sanchez-Sanchez, Mehmet Isik, Lourdes Irusta, Masaru Tanaka, Kazuki Fukushima, Haritz Sardon, Biocompatibility and hemocompatibility evaluation of polyether urethanes synthesized using DBU organocatalyst, European Polymer Journal, 10.1016/j.eurpolymj.2016.08.008, 84, 750-758, 2016.11, Biomaterials must fulfill some requirements before moving into in vivo application. In vitro test is usually conducted as a preliminary screening evaluation. Although most of the studies are focused in the cytotoxicity, interactions between blood elements and the biomaterials or hemocompatibility must also be considered. Aliphatic polyurethanes have been always considered ideal candidates for in-vivo application due to their versatility. However, the utilization of metal catalyst to promote the polymerization have limited their use. Recently, some organocatalysts have shown to be competitive to tin based catalyst for the preparation of polyurethanes and have relaunched their use in biomedicine. In the present study we carried out the organocatalyzed polymerization of 5 commercially available isocyanates, hexamethylene diisocyanate, isophorone diisocyanate, trans-1,4-cyclohexylene diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate) and L-lysine diisocyanate to analyze the cytotoxicity and hemocompatibility of the resultant polymers as a function of the employed diisocyanate. The diisocyanates were polymerized with hydroxy end-capped oligomeric poly (tetramethylene glycol) (PT2K) as the long chain diol and 1,3-propanediol as the short chain diol. We demonstrated that from selected diisocyanates, lysine diisocyanate based polyurethanes possessed lower cytotoxicity and better hemocompatibility than the other polyurethanes. In comparison with a well known blood compatible polymer such as poly(2-methoxyethyl acrylate), the lysine diisocyanate based polyurethanes showed remarkable values in terms of cytotoxicity and platelet adhesion, but major levels of protein adsorption..
113. Takashi Hoshiba, Masaru Tanaka, Decellularized matrices as in vitro models of extracellular matrix in tumor tissues at different malignant levels
Mechanism of 5-fluorouracil resistance in colorectal tumor cells, Biochimica et Biophysica Acta - Molecular Cell Research, 10.1016/j.bbamcr.2016.08.009, 1863, 11, 2749-2757, 2016.11, Chemoresistance is a major barrier for tumor chemotherapy. It is well-known that chemoresistance increases with tumor progression. Chemoresistance is altered by both genetic mutations and the alteration of extracellular microenvironment. Particularly, the extracellular matrix (ECM) is remodeled during tumor progression. Therefore, ECM remodeling is expected to cause the acquisition of chemoresistance in highly malignant tumor tissue. Here, we prepared cultured cell-derived decellularized matrices that mimic native ECM in tumor tissues at different stages of malignancy, and 5-fluorouracil (5-FU) resistance was compared among these matrices. 5-FU resistance of colorectal tumor cells increased on the matrices derived from highly malignant tumor HT-29 cells, although the resistance did not increase on the matrices derived from low malignant tumor SW480 cells and normal CCD-841-CoN cells. The resistance on HT-29 cell-derived matrices increased through the activation of Akt and the upregulation of ABCB1 and ABCC1 without cell growth promotion, suggesting that ECM remodeling plays important roles in the acquisition of chemoresistance during tumor progression. It is expected that our decellularized matrices, or “staged tumorigenesis-mimicking matrices”, will become preferred cell culture substrates for in vitro analysis of comprehensive ECM roles in chemoresistance and the screening and pharmacokinetic analysis of anti-cancer drugs..
114. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Hiroka Maruyama, Chiho Endo, Masaru Tanaka, Promotion of Adipogenesis of 3T3-L1 Cells on Protein Adsorption-Suppressing Poly(2-methoxyethyl acrylate) Analogs, Biomacromolecules, 10.1021/acs.biomac.6b01340, 17, 11, 3808-3815, 2016.11, Stem cell differentiation is an important issue in regenerative medicine and tissue engineering. It has been reported that cell shape is one of the factors that determine the lineage commitment of mesenchymal stem cells (MSCs). Therefore, the substrates have been developed to control their shapes. Recently, we found that poly(2-methoxyethyl acrylate) (PMEA) analogs can control tumor cell shape through the alteration of protein adsorption. Here, the adipogenesis of an adipocyte-progenitor cell, 3T3-L1 cells, was attempted; adipogenesis was to be regulated by surfaces coated with PMEA analogs through the control of their shape. The adipogenesis of 3T3-L1 cells was promoted on the surfaces coated with PMEA and its analogs, PMe3A and PMe2A. Evident focal adhesions were hardly observed on these surfaces, suggesting that integrin signal activation was suppressed. Additionally, actin assembly and cell spreading were suppressed on these surfaces. Therefore, the surfaces coated with PMEA analogs are expected to be suitable surfaces to regulate adipogenesis through the suppression of cell spreading. Additionally, we found that protein adsorption correlated with actin assembly and adipogenesis..
115. Kohei Osawa, Shingo Kobayashi, Masaru Tanaka, Synthesis of Sequence-Specific Polymers with Amide Side Chains via Regio-/Stereoselective Ring-Opening Metathesis Polymerization of 3-Substituted cis-Cyclooctene, Macromolecules, 10.1021/acs.macromol.6b01829, 49, 21, 8154-8161, 2016.11, Highly regio-/stereoregular (trans-head-to-tail) polymers with amide side chains on every eighth backbone carbon were successfully synthesized by ring-opening metathesis polymerization (ROMP) of 3-substituted cis-cyclooctene (3RCOE) using Grubbs second-generation catalyst (G2). Regioregular linear ethylene-acrylamide copolymers were also prepared via hydrogenation of the obtained poly(3RCOE)s. The thermal properties and solubility of the obtained polymers were strongly influenced by the presence of amide hydrogen in the side chains, the presence of unsaturated bonds in the carbon backbone, and the side chain density. The presence of amide hydrogen in the side chains resulted in the formation of crystalline polymers and the lack of solubility of these polymers in common organic solvents. In contrast, the absence of amide hydrogen in the side chains led to the formation of amorphous polymers exhibiting good solubility in common organic solvents, and decreasing values of Tg were observed for amorphous polymers as a result of the saturation of double bonds in the backbone via hydrogenation..
116. Andere Basterretxea, Yuta Haga, Ana Sanchez-Sanchez, Mehmet Isik, Lourdes Irusta, Masaru Tanaka, Kazuki Fukushima, Haritz Sardon, Biocompatibility and hemocompatibility evaluation of polyether urethanes synthesized using DBU organocatalyst, European Polymer Journal, 10.1016/j.eurpolymj.2016.08.008, 84, 750-758, 2016.11, Biomaterials must fulfill some requirements before moving into in vivo application. In vitro test is usually conducted as a preliminary screening evaluation. Although most of the studies are focused in the cytotoxicity, interactions between blood elements and the biomaterials or hemocompatibility must also be considered. Aliphatic polyurethanes have been always considered ideal candidates for in-vivo application due to their versatility. However, the utilization of metal catalyst to promote the polymerization have limited their use. Recently, some organocatalysts have shown to be competitive to tin based catalyst for the preparation of polyurethanes and have relaunched their use in biomedicine. In the present study we carried out the organocatalyzed polymerization of 5 commercially available isocyanates, hexamethylene diisocyanate, isophorone diisocyanate, trans-1,4-cyclohexylene diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate) and L-lysine diisocyanate to analyze the cytotoxicity and hemocompatibility of the resultant polymers as a function of the employed diisocyanate. The diisocyanates were polymerized with hydroxy end-capped oligomeric poly (tetramethylene glycol) (PT2K) as the long chain diol and 1,3-propanediol as the short chain diol. We demonstrated that from selected diisocyanates, lysine diisocyanate based polyurethanes possessed lower cytotoxicity and better hemocompatibility than the other polyurethanes. In comparison with a well known blood compatible polymer such as poly(2-methoxyethyl acrylate), the lysine diisocyanate based polyurethanes showed remarkable values in terms of cytotoxicity and platelet adhesion, but major levels of protein adsorption..
117. Takashi Hoshiba, Masaru Tanaka, Decellularized matrices as in vitro models of extracellular matrix in tumor tissues at different malignant levels
Mechanism of 5-fluorouracil resistance in colorectal tumor cells, Biochimica et Biophysica Acta - Molecular Cell Research, 10.1016/j.bbamcr.2016.08.009, 1863, 11, 2749-2757, 2016.11, Chemoresistance is a major barrier for tumor chemotherapy. It is well-known that chemoresistance increases with tumor progression. Chemoresistance is altered by both genetic mutations and the alteration of extracellular microenvironment. Particularly, the extracellular matrix (ECM) is remodeled during tumor progression. Therefore, ECM remodeling is expected to cause the acquisition of chemoresistance in highly malignant tumor tissue. Here, we prepared cultured cell-derived decellularized matrices that mimic native ECM in tumor tissues at different stages of malignancy, and 5-fluorouracil (5-FU) resistance was compared among these matrices. 5-FU resistance of colorectal tumor cells increased on the matrices derived from highly malignant tumor HT-29 cells, although the resistance did not increase on the matrices derived from low malignant tumor SW480 cells and normal CCD-841-CoN cells. The resistance on HT-29 cell-derived matrices increased through the activation of Akt and the upregulation of ABCB1 and ABCC1 without cell growth promotion, suggesting that ECM remodeling plays important roles in the acquisition of chemoresistance during tumor progression. It is expected that our decellularized matrices, or “staged tumorigenesis-mimicking matrices”, will become preferred cell culture substrates for in vitro analysis of comprehensive ECM roles in chemoresistance and the screening and pharmacokinetic analysis of anti-cancer drugs..
118. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Hiroka Maruyama, Chiho Endo, Masaru Tanaka, Promotion of Adipogenesis of 3T3-L1 Cells on Protein Adsorption-Suppressing Poly(2-methoxyethyl acrylate) Analogs, Biomacromolecules, 10.1021/acs.biomac.6b01340, 17, 11, 3808-3815, 2016.11, Stem cell differentiation is an important issue in regenerative medicine and tissue engineering. It has been reported that cell shape is one of the factors that determine the lineage commitment of mesenchymal stem cells (MSCs). Therefore, the substrates have been developed to control their shapes. Recently, we found that poly(2-methoxyethyl acrylate) (PMEA) analogs can control tumor cell shape through the alteration of protein adsorption. Here, the adipogenesis of an adipocyte-progenitor cell, 3T3-L1 cells, was attempted; adipogenesis was to be regulated by surfaces coated with PMEA analogs through the control of their shape. The adipogenesis of 3T3-L1 cells was promoted on the surfaces coated with PMEA and its analogs, PMe3A and PMe2A. Evident focal adhesions were hardly observed on these surfaces, suggesting that integrin signal activation was suppressed. Additionally, actin assembly and cell spreading were suppressed on these surfaces. Therefore, the surfaces coated with PMEA analogs are expected to be suitable surfaces to regulate adipogenesis through the suppression of cell spreading. Additionally, we found that protein adsorption correlated with actin assembly and adipogenesis..
119. Kohei Osawa, Shingo Kobayashi, Masaru Tanaka, Synthesis of Sequence-Specific Polymers with Amide Side Chains via Regio-/Stereoselective Ring-Opening Metathesis Polymerization of 3-Substituted cis-Cyclooctene, Macromolecules, 10.1021/acs.macromol.6b01829, 49, 21, 8154-8161, 2016.11, Highly regio-/stereoregular (trans-head-to-tail) polymers with amide side chains on every eighth backbone carbon were successfully synthesized by ring-opening metathesis polymerization (ROMP) of 3-substituted cis-cyclooctene (3RCOE) using Grubbs second-generation catalyst (G2). Regioregular linear ethylene-acrylamide copolymers were also prepared via hydrogenation of the obtained poly(3RCOE)s. The thermal properties and solubility of the obtained polymers were strongly influenced by the presence of amide hydrogen in the side chains, the presence of unsaturated bonds in the carbon backbone, and the side chain density. The presence of amide hydrogen in the side chains resulted in the formation of crystalline polymers and the lack of solubility of these polymers in common organic solvents. In contrast, the absence of amide hydrogen in the side chains led to the formation of amorphous polymers exhibiting good solubility in common organic solvents, and decreasing values of T
g
were observed for amorphous polymers as a result of the saturation of double bonds in the backbone via hydrogenation..
120. Andere Basterretxea, Yuta Haga, Ana Sanchez-Sanchez, Mehmet Isik, Lourdes Irusta, Masaru Tanaka, Kazuki Fukushima, Haritz Sardon, Biocompatibility and hemocompatibility evaluation of polyether urethanes synthesized using DBU organocatalyst, European Polymer Journal, 10.1016/j.eurpolymj.2016.08.008, 84, 750-758, 2016.11, Biomaterials must fulfill some requirements before moving into in vivo application. In vitro test is usually conducted as a preliminary screening evaluation. Although most of the studies are focused in the cytotoxicity, interactions between blood elements and the biomaterials or hemocompatibility must also be considered. Aliphatic polyurethanes have been always considered ideal candidates for in-vivo application due to their versatility. However, the utilization of metal catalyst to promote the polymerization have limited their use. Recently, some organocatalysts have shown to be competitive to tin based catalyst for the preparation of polyurethanes and have relaunched their use in biomedicine. In the present study we carried out the organocatalyzed polymerization of 5 commercially available isocyanates, hexamethylene diisocyanate, isophorone diisocyanate, trans-1,4-cyclohexylene diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate) and L-lysine diisocyanate to analyze the cytotoxicity and hemocompatibility of the resultant polymers as a function of the employed diisocyanate. The diisocyanates were polymerized with hydroxy end-capped oligomeric poly (tetramethylene glycol) (PT2K) as the long chain diol and 1,3-propanediol as the short chain diol. We demonstrated that from selected diisocyanates, lysine diisocyanate based polyurethanes possessed lower cytotoxicity and better hemocompatibility than the other polyurethanes. In comparison with a well known blood compatible polymer such as poly(2-methoxyethyl acrylate), the lysine diisocyanate based polyurethanes showed remarkable values in terms of cytotoxicity and platelet adhesion, but major levels of protein adsorption..
121. Takashi Hoshiba, Masaru Tanaka, Decellularized matrices as in vitro models of extracellular matrix in tumor tissues at different malignant levels
Mechanism of 5-fluorouracil resistance in colorectal tumor cells, Biochimica et Biophysica Acta - Molecular Cell Research, 10.1016/j.bbamcr.2016.08.009, 1863, 11, 2749-2757, 2016.11, Chemoresistance is a major barrier for tumor chemotherapy. It is well-known that chemoresistance increases with tumor progression. Chemoresistance is altered by both genetic mutations and the alteration of extracellular microenvironment. Particularly, the extracellular matrix (ECM) is remodeled during tumor progression. Therefore, ECM remodeling is expected to cause the acquisition of chemoresistance in highly malignant tumor tissue. Here, we prepared cultured cell-derived decellularized matrices that mimic native ECM in tumor tissues at different stages of malignancy, and 5-fluorouracil (5-FU) resistance was compared among these matrices. 5-FU resistance of colorectal tumor cells increased on the matrices derived from highly malignant tumor HT-29 cells, although the resistance did not increase on the matrices derived from low malignant tumor SW480 cells and normal CCD-841-CoN cells. The resistance on HT-29 cell-derived matrices increased through the activation of Akt and the upregulation of ABCB1 and ABCC1 without cell growth promotion, suggesting that ECM remodeling plays important roles in the acquisition of chemoresistance during tumor progression. It is expected that our decellularized matrices, or “staged tumorigenesis-mimicking matrices”, will become preferred cell culture substrates for in vitro analysis of comprehensive ECM roles in chemoresistance and the screening and pharmacokinetic analysis of anti-cancer drugs..
122. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Hiroka Maruyama, Chiho Endo, Masaru Tanaka, Promotion of Adipogenesis of 3T3-L1 Cells on Protein Adsorption-Suppressing Poly(2-methoxyethyl acrylate) Analogs, Biomacromolecules, 10.1021/acs.biomac.6b01340, 17, 11, 3808-3815, 2016.11, Stem cell differentiation is an important issue in regenerative medicine and tissue engineering. It has been reported that cell shape is one of the factors that determine the lineage commitment of mesenchymal stem cells (MSCs). Therefore, the substrates have been developed to control their shapes. Recently, we found that poly(2-methoxyethyl acrylate) (PMEA) analogs can control tumor cell shape through the alteration of protein adsorption. Here, the adipogenesis of an adipocyte-progenitor cell, 3T3-L1 cells, was attempted; adipogenesis was to be regulated by surfaces coated with PMEA analogs through the control of their shape. The adipogenesis of 3T3-L1 cells was promoted on the surfaces coated with PMEA and its analogs, PMe3A and PMe2A. Evident focal adhesions were hardly observed on these surfaces, suggesting that integrin signal activation was suppressed. Additionally, actin assembly and cell spreading were suppressed on these surfaces. Therefore, the surfaces coated with PMEA analogs are expected to be suitable surfaces to regulate adipogenesis through the suppression of cell spreading. Additionally, we found that protein adsorption correlated with actin assembly and adipogenesis..
123. Kohei Osawa, Shingo Kobayashi, Masaru Tanaka, Synthesis of Sequence-Specific Polymers with Amide Side Chains via Regio-/Stereoselective Ring-Opening Metathesis Polymerization of 3-Substituted cis-Cyclooctene, Macromolecules, 10.1021/acs.macromol.6b01829, 49, 21, 8154-8161, 2016.11, Highly regio-/stereoregular (trans-head-to-tail) polymers with amide side chains on every eighth backbone carbon were successfully synthesized by ring-opening metathesis polymerization (ROMP) of 3-substituted cis-cyclooctene (3RCOE) using Grubbs second-generation catalyst (G2). Regioregular linear ethylene-acrylamide copolymers were also prepared via hydrogenation of the obtained poly(3RCOE)s. The thermal properties and solubility of the obtained polymers were strongly influenced by the presence of amide hydrogen in the side chains, the presence of unsaturated bonds in the carbon backbone, and the side chain density. The presence of amide hydrogen in the side chains resulted in the formation of crystalline polymers and the lack of solubility of these polymers in common organic solvents. In contrast, the absence of amide hydrogen in the side chains led to the formation of amorphous polymers exhibiting good solubility in common organic solvents, and decreasing values of T
g
were observed for amorphous polymers as a result of the saturation of double bonds in the backbone via hydrogenation..
124. Andere Basterretxea, Yuta Haga, Ana Sanchez-Sanchez, Mehmet Isik, Lourdes Irusta, Masaru Tanaka, Kazuki Fukushima, Haritz Sardon, Biocompatibility and hemocompatibility evaluation of polyether urethanes synthesized using DBU organocatalyst, EUROPEAN POLYMER JOURNAL, 10.1016/j.eurpolymj.2016.08.008, 84, 750-758, 2016.11, Biomaterials must fulfill some requirements before moving into in vivo application. In vitro test is usually conducted as a preliminary screening evaluation. Although most of the studies are focused in the cytotoxicity, interactions between blood elements and the bio-materials or hemocompatibility must also be considered. Aliphatic polyurethanes have been always considered ideal candidates for in-vivo application due to their versatility. However, the utilization of metal catalyst to promote the polymerization have limited their use. Recently, some organocatalysts have shown to be competitive to tin based catalyst for the preparation of polyurethanes and have relaunched their use in biomedicine. In the present study we carried out the organocatalyzed polymerization of 5 commercially available isocyanates, hexamethylene diisocyanate, isophorone diisocyanate, trans-1,4-cyclohexylene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate) and L-lysine diisocyanate to analyze the cytotoxicity and hemocompatibility of the resultant polymers as a function of the employed diisocyanate. The diisocyanates were polymerized with hydroxy end-capped oligomeric poly (tetramethylene glycol) (PT2K) as the long chain diol and 1,3-propanediol as the short chain diol. We demonstrated that from selected diisocyanates, lysine diisocyanate based polyurethanes possessed lower cytotoxicity and better hemocompatibility than the other polyurethanes. In comparison with a well known blood compatible polymer such as poly(2-methoxyethyl acrylate), the lysine diisocyanate based polyurethanes showed remarkable values in terms of cytotoxicity and platelet adhesion, but major levels of protein adsorption. (C) 2016 Elsevier Ltd. All rights reserved..
125. Takashi Hoshiba, Masaru Tanaka, Decellularized matrices as in vitro models of extracellular matrix in tumor tissues at different malignant levels: Mechanism of 5-fluorouracil resistance in colorectal tumor cells, BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH, 10.1016/j.bbamcr.2016.08.009, 1863, 11, 2749-2757, 2016.11, Chemoresistance is a major barrier for tumor chemotherapy. It is well-known that chemoresistance increases with tumor progression. Chemoresistance is altered by both genetic mutations and the alteration of extracellular microenvironment. Particularly, the extracellular matrix (ECM) is remodeled during tumor progression. Therefore, ECM remodeling is expected to cause the acquisition of chemoresistance in highly malignant tumor tissue. Here, we prepared cultured cell-derived decellularized matrices that mimic native ECM in tumor tissues at different stages of malignancy, and 5-fluorouracil (5-FU) resistance was compared among these matrices. 5-FU resistance of colorectal tumor cells increased on the matrices derived from highly malignant tumor HT-29 cells, although the resistance did not increase on the matrices derived from low malignant tumor SW480 cells and normal CCD-841-CoN cells. The resistance on HT-29 cell-derived matrices increased through the activation of Akt and the upregulation of ABCB1 and ABCC1 without cell growth promotion, suggesting that ECM remodeling plays important roles in the acquisition of chemoresistance during tumor progression. It is expected that our decellularized matrices, or "staged tumorigenesis-mimicking matrices", will become preferred cell culture substrates for in vitro analysis of comprehensive ECM roles in chemoresistance and the screening and pharmacokinetic analysis of anti-cancer drugs. (C) 2016 Elsevier B.V. All rights reserved..
126. Takashi Hoshiba, Masaru Tanaka, Integrin-independent Cell Adhesion Substrates: Possibility of Applications for Mechanobiology Research, ANALYTICAL SCIENCES, 10.2116/analsci.32.1151, 32, 11, 1151-1158, 2016.11, Cells can mainly sense mechanical cues from the extracellular matrix via integrins. Because mechanical cues can strongly influence cellular functions, understanding the roles of integrins in the sensing of mechanical cues is a key for the achievement of tissue engineering. The analyses to determine the roles of integrins in the sensing of mechanical cues have been performed by many methods based on molecular- and cell-biological techniques, atomic force microscopy, and optical tweezers. Integrin-dependent cell adhesion substrates have been also used for this purpose. Additionally, the cells can adhere on several substrates via integrin-independent mechanisms. There are two types of integrin-independent cell adhesion substrates; 1) the substrates immobilized with ligands against the receptors on cell surface and 2) the substrates suppressing protein adsorption. Cells can exhibit specific functions on these substrates. Here, the examples of integrin-independent cell adhesion substrates were reviewed, and their possible applications in mechanobiology research are discussed..
127. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Hiroka Maruyama, Chiho Endo, Masaru Tanaka, Promotion of Adipogenesis of 3T3-L1 Cells on Protein Adsorption Suppressing Poly(2-methoxyethyl acrylate) Analogs, BIOMACROMOLECULES, 10.1021/acs.biomac.6b01340, 17, 11, 3808-3815, 2016.11, Stem cell differentiation is an important issue in regenerative medicine and tissue engineering. It has been reported that cell shape is one of the factors that determine the lineage commitment of mesenchymal stem cells (MSCs). Therefore, the substrates have been developed to control their shapes. Recently, we found that poly(2-methoxyethyl acrylate) (PMEA) analogs can control tumor cell shape through the alteration of protein adsorption. Here, the adipogenesis of an adipocyte-progenitor cell, 3T3-L1 cells, was attempted; adipogenesis was to be regulated by surfaces coated with PMEA analogs through the control of their shape. The adipogenesis of 3T3-L1 cells was promoted on the surfaces coated with PMEA and its analogs, PMe3A and PMe2A. Evident focal adhesions were hardly observed on these surfaces, suggesting that integrin signal activation was suppressed. Additionally, actin assembly and cell spreading were suppressed on these surfaces. Therefore, the surfaces coated with PMEA analogs are expected to be suitable surfaces to regulate adipogenesis through the suppression of cell spreading. Additionally, we found that protein adsorption correlated with actin assembly and adipogenesis..
128. Kohei Osawa, Shingo Kobayashi, Masaru Tanaka, Synthesis of Sequence-Specific Polymers with Amide Side Chains via Regio-/Stereoselective Ring-Opening Metathesis Polymerization of 3-Substituted cis-Cyclooctene, MACROMOLECULES, 10.1021/acs.macromol.6b01829, 49, 21, 8154-8161, 2016.11, Highly regio-/stereoregular (trans-head-to-tail) polymers with amide side chains on every eighth backbone carbon were successfully synthesized by ring-opening metathesis polymerization (ROMP) of 3-substituted cis-cyclooctene (3RCOE) using Grubbs second-generation catalyst (G2). Regioregular linear ethylene acrylamide copolymers were also prepared via hydrogenation of the obtained poly(3RCOE)s. The thermal properties and solubility of the obtained polymers were strongly influenced by the presence of amide hydrogen in the side chains, the presence of unsaturated bonds in the carbon backbone, and the side chain density. The presence of amide hydrogen in the side chains resulted in the formation of crystalline polymers and the lack of solubility of these polymers in common organic solvents. In contrast, the absence of amide hydrogen in the side chains led to the formation of amorphous polymers exhibiting good solubility in common organic solvents, and decreasing values of T-g were observed for amorphous polymers as a result of the saturation of double bonds in the backbone via hydrogenation..
129. Masaru Tanaka, H. Choi, M. Tanaka, K. Sugimoto, Difference in cell proliferation and spontaneous mediator release between two mast cell lines, NCL-2 and RBL-2H3 on honeycomb-like structured film, Journal of Nanotechnology: Nanomedicine & Nanobiotechnology, 3, 009, 2016.10.
130. Chikako Sato, Makiko Aoki, Masaru Tanaka, Blood-compatible poly(2-methoxyethyl acrylate) for the adhesion and proliferation of endothelial and smooth muscle cells., Colloids and Surfaces B: Biointerfaces, 10.1016/j.colsurfb.2016.05.057, 145, 586-596, 2016.09, Thrombus formation presents a serious hindrance in the development of functional artificial blood vessels, especially those with a small diameter. Endothelialization can prevent thrombus formation; however, the adhesion of endothelial cells to existing polymer materials is generally weak. Therefore, polymers that have both anti-thrombotic and endothelialization properties do not currently exist. We previously reported that platelets do not adhere to poly(2-methoxyethyl acrylate) (PMEA) or poly(tetrahydrofurfuryl acrylate)(PTHFA). Here, we investigated whether endothelial cells and smooth muscle cells, both of which are blood vessel components, could adhere to these synthetic polymers. Polyethylene terephthalate films were coated with PMEA and PTHFA using a spin-coater. Human umbilical vein endothelial cells or aorta smooth muscle cells were seeded on the polymer surfaces, after which we analyzed the number of adherent cells, their morphologies and vinculin expression. We found that both endothelial and smooth muscle cells adhered to PMEA and PTHFA, while platelets did not. We propose that, by using PMEA and PTHFA with no modifications, it should be possible to develop artificial blood vessels with both anti-thrombotic and endothelialization properties. In addition, we discuss the mechanism of selective cell adhesion in PMEA and PTHFA..
131. Chikako Sato, Makiko Aoki, Masaru Tanaka, Blood-compatible poly(2-methoxyethyl acrylate) for the adhesion and proliferation of endothelial and smooth muscle cells., Colloids and Surfaces B: Biointerfaces, 10.1016/j.colsurfb.2016.05.057, 145, 586-596, 2016.09, Thrombus formation presents a serious hindrance in the development of functional artificial blood vessels, especially those with a small diameter. Endothelialization can prevent thrombus formation; however, the adhesion of endothelial cells to existing polymer materials is generally weak. Therefore, polymers that have both anti-thrombotic and endothelialization properties do not currently exist. We previously reported that platelets do not adhere to poly(2-methoxyethyl acrylate) (PMEA) or poly(tetrahydrofurfuryl acrylate)(PTHFA). Here, we investigated whether endothelial cells and smooth muscle cells, both of which are blood vessel components, could adhere to these synthetic polymers. Polyethylene terephthalate films were coated with PMEA and PTHFA using a spin-coater. Human umbilical vein endothelial cells or aorta smooth muscle cells were seeded on the polymer surfaces, after which we analyzed the number of adherent cells, their morphologies and vinculin expression. We found that both endothelial and smooth muscle cells adhered to PMEA and PTHFA, while platelets did not. We propose that, by using PMEA and PTHFA with no modifications, it should be possible to develop artificial blood vessels with both anti-thrombotic and endothelialization properties. In addition, we discuss the mechanism of selective cell adhesion in PMEA and PTHFA..
132. Chikako Sato, Makiko Aoki, Masaru Tanaka, Blood-compatible poly(2-methoxyethyl acrylate) for the adhesion and proliferation of endothelial and smooth muscle cells., Colloids and Surfaces B: Biointerfaces, 10.1016/j.colsurfb.2016.05.057, 145, 586-596, 2016.09, Thrombus formation presents a serious hindrance in the development of functional artificial blood vessels, especially those with a small diameter. Endothelialization can prevent thrombus formation; however, the adhesion of endothelial cells to existing polymer materials is generally weak. Therefore, polymers that have both anti-thrombotic and endothelialization properties do not currently exist. We previously reported that platelets do not adhere to poly(2-methoxyethyl acrylate) (PMEA) or poly(tetrahydrofurfuryl acrylate)(PTHFA). Here, we investigated whether endothelial cells and smooth muscle cells, both of which are blood vessel components, could adhere to these synthetic polymers. Polyethylene terephthalate films were coated with PMEA and PTHFA using a spin-coater. Human umbilical vein endothelial cells or aorta smooth muscle cells were seeded on the polymer surfaces, after which we analyzed the number of adherent cells, their morphologies and vinculin expression. We found that both endothelial and smooth muscle cells adhered to PMEA and PTHFA, while platelets did not. We propose that, by using PMEA and PTHFA with no modifications, it should be possible to develop artificial blood vessels with both anti-thrombotic and endothelialization properties. In addition, we discuss the mechanism of selective cell adhesion in PMEA and PTHFA..
133. Chikako Sato, Makiko Aoki, Masaru Tanaka, Blood-compatible poly(2-methoxyethyl acrylate) for the adhesion and proliferation of endothelial and smooth muscle cells., COLLOIDS AND SURFACES B-BIOINTERFACES, 10.1016/j.colsurfb.2016.05.057, 145, 586-596, 2016.09, Thrombus formation presents a serious hindrance in the development of functional artificial blood vessels, especially those with a small diameter. Endothelialization can prevent thrombus formation; however, the adhesion of endothelial cells to existing polymer materials is generally weak. Therefore, polymers that have both anti-thrombotic and endothelialization properties do not currently exist. We previously reported that platelets do not adhere to poly(2-methoxyethyl acrylate) (PMEA) or poly(tetrahydrofurfuryl acrylate)(PTHFA). Here, we investigated whether endothelial cells and smooth muscle cells, both of which are blood vessel components, could adhere to these synthetic polymers. Polyethylene terephthalate films were coated with PMEA and PTHFA using a spin-coater. Human umbilical vein endothelial cells or aorta smooth muscle cells were seeded on the polymer surfaces, after which we analyzed the number of adherent cells, their morphologies and vinculin expression. We found that both endothelial and smooth muscle cells adhered to PMEA and PTHFA, while platelets did not. We propose that, by using PMEA and PTHFA with no modifications, it should be possible to develop artificial blood vessels with both anti-thrombotic and endothelialization properties. In addition, we discuss the mechanism of selective cell adhesion in PMEA and PTHFA. (C) 2016 Elsevier B.V. All rights reserved..
134. Takashi Hoshiba, Mayo Nikaido, Satomi Yagi, Iku Konno, Ayano Yoshihiro, Masaru Tanaka, Blood-compatible poly (2-methoxyethyl acrylate) for the adhesion and proliferation of lung cancer cells toward the isolation and analysis of circulating tumor cells, Journal of Bioactive and Compatible Polymers, 10.1177/0883911515618976, 31, 4, 361-372, 2016.07, Circulating tumor cells have received attention for their role in cancer diagnosis and the decision on which chemotherapeutic course to take. For these purposes, the isolation of circulating tumor cells has been important. Previously, we reported that non-blood cells can adhere on blood-compatible polymer substrates, such as poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate). In this study, we examined whether blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) allow the adhesion and growth of A549 lung cancer cells for isolating circulating tumor cells by adhesion-mediated manner to diagnose metastatic cancer and to decide on the chemotherapeutic course. A549 cells can adhere on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates via an integrin-dependent mechanism after 1 h of incubation, suggesting that blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates possess the ability to capture circulating tumor cells selectively from peripheral blood. After 1 day of culture, A549 cells started to spread on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. A549 can also grow on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. Additionally, the chemoresistance of A549 cells against 5-fluorouracil on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates was similar to that on the conventional cell culture substrate, tissue culture polystyrene. These results indicate that circulating tumor cells can be cultured on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates after they are isolated from peripheral blood, and poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates can be used as circulating tumor cell culture substrates for screening anti-cancer drugs. Therefore, poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates might be able to be applied to the development of a new device for a circulating tumor cell-based diagnosis of metastatic cancer and a personalized medicine approach regarding the decision of which chemotherapeutic course should be taken..
135. Takashi Hoshiba, Mayo Nikaido, Satomi Yagi, Iku Konno, Ayano Yoshihiro, Masaru Tanaka, Blood-compatible poly (2-methoxyethyl acrylate) for the adhesion and proliferation of lung cancer cells toward the isolation and analysis of circulating tumor cells, Journal of Bioactive and Compatible Polymers, 10.1177/0883911515618976, 31, 4, 361-372, 2016.07, Circulating tumor cells have received attention for their role in cancer diagnosis and the decision on which chemotherapeutic course to take. For these purposes, the isolation of circulating tumor cells has been important. Previously, we reported that non-blood cells can adhere on blood-compatible polymer substrates, such as poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate). In this study, we examined whether blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) allow the adhesion and growth of A549 lung cancer cells for isolating circulating tumor cells by adhesion-mediated manner to diagnose metastatic cancer and to decide on the chemotherapeutic course. A549 cells can adhere on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates via an integrin-dependent mechanism after 1 h of incubation, suggesting that blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates possess the ability to capture circulating tumor cells selectively from peripheral blood. After 1 day of culture, A549 cells started to spread on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. A549 can also grow on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. Additionally, the chemoresistance of A549 cells against 5-fluorouracil on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates was similar to that on the conventional cell culture substrate, tissue culture polystyrene. These results indicate that circulating tumor cells can be cultured on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates after they are isolated from peripheral blood, and poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates can be used as circulating tumor cell culture substrates for screening anti-cancer drugs. Therefore, poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates might be able to be applied to the development of a new device for a circulating tumor cell-based diagnosis of metastatic cancer and a personalized medicine approach regarding the decision of which chemotherapeutic course should be taken..
136. Takashi Hoshiba, Mayo Nikaido, Satomi Yagi, Iku Konno, Ayano Yoshihiro, Masaru Tanaka, Blood-compatible poly (2-methoxyethyl acrylate) for the adhesion and proliferation of lung cancer cells toward the isolation and analysis of circulating tumor cells, Journal of Bioactive and Compatible Polymers, 10.1177/0883911515618976, 31, 4, 361-372, 2016.07, Circulating tumor cells have received attention for their role in cancer diagnosis and the decision on which chemotherapeutic course to take. For these purposes, the isolation of circulating tumor cells has been important. Previously, we reported that non-blood cells can adhere on blood-compatible polymer substrates, such as poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate). In this study, we examined whether blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) allow the adhesion and growth of A549 lung cancer cells for isolating circulating tumor cells by adhesion-mediated manner to diagnose metastatic cancer and to decide on the chemotherapeutic course. A549 cells can adhere on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates via an integrin-dependent mechanism after 1 h of incubation, suggesting that blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates possess the ability to capture circulating tumor cells selectively from peripheral blood. After 1 day of culture, A549 cells started to spread on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. A549 can also grow on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. Additionally, the chemoresistance of A549 cells against 5-fluorouracil on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates was similar to that on the conventional cell culture substrate, tissue culture polystyrene. These results indicate that circulating tumor cells can be cultured on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates after they are isolated from peripheral blood, and poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates can be used as circulating tumor cell culture substrates for screening anti-cancer drugs. Therefore, poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates might be able to be applied to the development of a new device for a circulating tumor cell-based diagnosis of metastatic cancer and a personalized medicine approach regarding the decision of which chemotherapeutic course should be taken..
137. Takashi Hoshiba, Mayo Nikaido, Satomi Yagi, Iku Konno, Ayano Yoshihiro, Masaru Tanaka, Blood-compatible poly (2-methoxyethyl acrylate) for the adhesion and proliferation of lung cancer cells toward the isolation and analysis of circulating tumor cells, JOURNAL OF BIOACTIVE AND COMPATIBLE POLYMERS, 10.1177/0883911515618976, 31, 4, 361-372, 2016.07, Circulating tumor cells have received attention for their role in cancer diagnosis and the decision on which chemotherapeutic course to take. For these purposes, the isolation of circulating tumor cells has been important. Previously, we reported that non-blood cells can adhere on blood-compatible polymer substrates, such as poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate). In this study, we examined whether blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) allow the adhesion and growth of A549 lung cancer cells for isolating circulating tumor cells by adhesion-mediated manner to diagnose metastatic cancer and to decide on the chemotherapeutic course. A549 cells can adhere on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates via an integrin-dependent mechanism after 1h of incubation, suggesting that blood-compatible poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates possess the ability to capture circulating tumor cells selectively from peripheral blood. After 1day of culture, A549 cells started to spread on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. A549 can also grow on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates. Additionally, the chemoresistance of A549 cells against 5-fluorouracil on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates was similar to that on the conventional cell culture substrate, tissue culture polystyrene. These results indicate that circulating tumor cells can be cultured on poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates after they are isolated from peripheral blood, and poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates can be used as circulating tumor cell culture substrates for screening anti-cancer drugs. Therefore, poly(2-methoxyethyl acrylate) and poly(tetrahydrofurfuryl acrylate) substrates might be able to be applied to the development of a new device for a circulating tumor cell-based diagnosis of metastatic cancer and a personalized medicine approach regarding the decision of which chemotherapeutic course should be taken..
138. Ken Kono, Hitomi Hiruma, Shingo Kobayashi, Yoji Sato, Masaru Tanaka, Rumi Sawada, Shingo Niimi, In vitro endothelialization test of biomaterials using immortalized endothelial cells, PLoS One, 10.1371/journal.pone.0158289, 11, 6, 2016.06, Functionalizing biomaterials with peptides or polymers that enhance recruitment of endothelial cells (ECs) can reduce blood coagulation and thrombosis. To assess endothelialization of materials in vitro, primary ECs are generally used, although the characteristics of these cells vary among the donors and change with time in culture. Recently, primary cell lines immortalized by transduction of simian vacuolating virus 40 large T antigen or human telomerase reverse transcriptase have been developed. To determine whether immortalized ECs can substitute for primary ECs in material testing, we investigated endothelialization on biocompatible polymers using three lots of primary human umbilical vein endothelial cells (HUVEC) and immortalized microvascular ECs, TIME-GFP. Attachment to and growth on polymer surfaces were comparable between cell types, but results were more consistent with TIME-GFP. Our findings indicate that TIME-GFP is more suitable for in vitro endothelialization testing of biomaterials..
139. Ken Kono, Hitomi Hiruma, Shingo Kobayashi, Yoji Sato, Masaru Tanaka, Rumi Sawada, Shingo Niimi, In vitro endothelialization test of biomaterials using immortalized endothelial cells, PLoS One, 10.1371/journal.pone.0158289, 11, 6, 2016.06, Functionalizing biomaterials with peptides or polymers that enhance recruitment of endothelial cells (ECs) can reduce blood coagulation and thrombosis. To assess endothelialization of materials in vitro, primary ECs are generally used, although the characteristics of these cells vary among the donors and change with time in culture. Recently, primary cell lines immortalized by transduction of simian vacuolating virus 40 large T antigen or human telomerase reverse transcriptase have been developed. To determine whether immortalized ECs can substitute for primary ECs in material testing, we investigated endothelialization on biocompatible polymers using three lots of primary human umbilical vein endothelial cells (HUVEC) and immortalized microvascular ECs, TIME-GFP. Attachment to and growth on polymer surfaces were comparable between cell types, but results were more consistent with TIME-GFP. Our findings indicate that TIME-GFP is more suitable for in vitro endothelialization testing of biomaterials..
140. Ken Kono, Hitomi Hiruma, Shingo Kobayashi, Yoji Sato, Masaru Tanaka, Rumi Sawada, Shingo Niimi, In vitro endothelialization test of biomaterials using immortalized endothelial cells, PloS one, 10.1371/journal.pone.0158289, 11, 6, 2016.06, Functionalizing biomaterials with peptides or polymers that enhance recruitment of endothelial cells (ECs) can reduce blood coagulation and thrombosis. To assess endothelialization of materials in vitro, primary ECs are generally used, although the characteristics of these cells vary among the donors and change with time in culture. Recently, primary cell lines immortalized by transduction of simian vacuolating virus 40 large T antigen or human telomerase reverse transcriptase have been developed. To determine whether immortalized ECs can substitute for primary ECs in material testing, we investigated endothelialization on biocompatible polymers using three lots of primary human umbilical vein endothelial cells (HUVEC) and immortalized microvascular ECs, TIME-GFP. Attachment to and growth on polymer surfaces were comparable between cell types, but results were more consistent with TIME-GFP. Our findings indicate that TIME-GFP is more suitable for in vitro endothelialization testing of biomaterials..
141. Ken Kono, Hitomi Hiruma, Shingo Kobayashi, Yoji Sato, Masaru Tanaka, Rumi Sawada, Shingo Niimi, In Vitro Endothelialization Test of Biomaterials Using Immortalized Endothelial Cells, PLOS ONE, 10.1371/journal.pone.0158289, 11, 6, 2016.06, Functionalizing biomaterials with peptides or polymers that enhance recruitment of endothelial cells (ECs) can reduce blood coagulation and thrombosis. To assess endothelialization of materials in vitro, primary ECs are generally used, although the characteristics of these cells vary among the donors and change with time in culture. Recently, primary cell lines immortalized by transduction of simian vacuolating virus 40 large T antigen or human telomerase reverse transcriptase have been developed. To determine whether immortalized ECs can substitute for primary ECs in material testing, we investigated endothelialization on biocompatible polymers using three lots of primary human umbilical vein endothelial cells (HUVEC) and immortalized microvascular ECs, TIME-GFP. Attachment to and growth on polymer surfaces were comparable between cell types, but results were more consistent with TIME-GFP. Our findings indicate that TIME-GFP is more suitable for in vitro endothelialization testing of biomaterials..
142. Shingo Kobayashi, Kousaku Fukuda, Maiko Kataoka, Masaru Tanaka, Regioselective Ring-Opening Metathesis Polymerization of 3-Substituted Cyclooctenes with Ether Side Chains., Macromolecules, 10.1021/acs.macromol.6b00273, 49, 7, 2493-2501, 2016.04, Allyl-substituted cyclooctenes with ether side-chains [methoxy, methoxy-terminated oligo(ethylene glycol)s, and tetrahydrofurfuryloxy group] were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst. In all cases, the ROMP of allyl-substituted monomers proceeded in a regio- and stereoselective manner to afford polymers with remarkably high head-to-tail regioregularity with high trans-stereoregularity. The regio- and stereoregularity of polymers were affected by the bulkiness of the substituent, and the ROMP of tetrahydrofurfuryloxy-substituted cyclooctene exhibited nearly perfect regio- (head-to-tail = 99%) and stereoselectivity (trans-double bond = 99%). Chemical hydrogenation of obtained polymers afforded model poly(ethylene-co-vinyl ether)s with precisely placed ether branches on every eighth backbone carbon. Differential scanning calorimetry (DSC) was used to study the thermal properties, and the hydrophilicity of polymers was evaluated by water contact angle measurement. The surface hydrophilicity of unsaturated polymers was effectively tuned by changing the side-chain length of oligo(ethylene glycol) groups while maintaining the hydrophobic character unchanged for saturated versions..
143. Shingo Kobayashi, Kousaku Fukuda, Maiko Kataoka, Masaru Tanaka, Regioselective Ring-Opening Metathesis Polymerization of 3-Substituted Cyclooctenes with Ether Side Chains., Macromolecules, 10.1021/acs.macromol.6b00273, 49, 7, 2493-2501, 2016.04, Allyl-substituted cyclooctenes with ether side-chains [methoxy, methoxy-terminated oligo(ethylene glycol)s, and tetrahydrofurfuryloxy group] were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst. In all cases, the ROMP of allyl-substituted monomers proceeded in a regio- and stereoselective manner to afford polymers with remarkably high head-to-tail regioregularity with high trans-stereoregularity. The regio- and stereoregularity of polymers were affected by the bulkiness of the substituent, and the ROMP of tetrahydrofurfuryloxy-substituted cyclooctene exhibited nearly perfect regio- (head-to-tail = 99%) and stereoselectivity (trans-double bond = 99%). Chemical hydrogenation of obtained polymers afforded model poly(ethylene-co-vinyl ether)s with precisely placed ether branches on every eighth backbone carbon. Differential scanning calorimetry (DSC) was used to study the thermal properties, and the hydrophilicity of polymers was evaluated by water contact angle measurement. The surface hydrophilicity of unsaturated polymers was effectively tuned by changing the side-chain length of oligo(ethylene glycol) groups while maintaining the hydrophobic character unchanged for saturated versions..
144. Shingo Kobayashi, Kousaku Fukuda, Maiko Kataoka, Masaru Tanaka, Regioselective Ring-Opening Metathesis Polymerization of 3-Substituted Cyclooctenes with Ether Side Chains., Macromolecules, 10.1021/acs.macromol.6b00273, 49, 7, 2493-2501, 2016.04, Allyl-substituted cyclooctenes with ether side-chains [methoxy, methoxy-terminated oligo(ethylene glycol)s, and tetrahydrofurfuryloxy group] were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst. In all cases, the ROMP of allyl-substituted monomers proceeded in a regio- and stereoselective manner to afford polymers with remarkably high head-to-tail regioregularity with high trans-stereoregularity. The regio- and stereoregularity of polymers were affected by the bulkiness of the substituent, and the ROMP of tetrahydrofurfuryloxy-substituted cyclooctene exhibited nearly perfect regio- (head-to-tail = 99%) and stereoselectivity (trans-double bond = 99%). Chemical hydrogenation of obtained polymers afforded model poly(ethylene-co-vinyl ether)s with precisely placed ether branches on every eighth backbone carbon. Differential scanning calorimetry (DSC) was used to study the thermal properties, and the hydrophilicity of polymers was evaluated by water contact angle measurement. The surface hydrophilicity of unsaturated polymers was effectively tuned by changing the side-chain length of oligo(ethylene glycol) groups while maintaining the hydrophobic character unchanged for saturated versions..
145. Shingo Kobayashi, Kousaku Fukuda, Maiko Kataoka, Masaru Tanaka, Regioselective Ring-Opening Metathesis Polymerization of 3-Substituted Cyclooctenes with Ether Side Chains., MACROMOLECULES, 10.1021/acs.macromol.6b00273, 49, 7, 2493-2501, 2016.04, Allyl-substituted cyclooctenes with ether side chains [methoxy, methoxy-terminated oligo(ethylene glycol)s, and tetrahydrofurfuryloxy group] were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst. In all cases, the ROMP of allyl-substituted monomers proceeded in a regio- and stereoselective manner to afford polymers with remarkably high head-to-tail regioregularity with high transstereoregularity. The regio- and stereoregularity of polymers were affected by the bulkiness of the substituent, and the ROMP of tetrahydrofurfuryloxy-substituted cyclooctene exhibited nearly perfect regio- (head-to-tail = 99%) and stereoselectivity (trans double bond = 99%). Chemical hydrogenation of obtained polymers afforded model poly(ethylene-co-vinyl ether)s with precisely placed ether branches on every eighth backbone carbon. Differential scanning calorimetry (DSC) was used to study the thermal properties, and the hydrophilicity of polymers was evaluated by water contact angle measurement. The surface hydrophilicity of unsaturated polymers was effectively tuned by changing the side-chain length of oligo(ethylene glycol) groups while maintaining the hydrophobic character unchanged for saturated versions..
146. Takashi Hoshiba, Toshihiko Orui, Chiho Endo, Kazuhiro Sato, Ayano Yoshihiro, Yasuhisa Minagawa, Masaru Tanaka, Adhesion-based simple capture and recovery of circulating tumor cells using a blood-compatible and thermo-responsive polymer-coated substrate, RSC Advances, 10.1039/c6ra15229e, 6, 92, 89103-89112, 2016.01, Circulating tumor cells (CTCs) have been a focus of study for metastatic cancer diagnostics, in in vitro anti-cancer drug screening to decide the chemotherapeutic course, and cancer biology research. For these purposes, there have been efforts made to collect CTCs from the peripheral blood of cancer patients. Here, we explore the possibility of collecting CTCs using blood-compatible and thermo-responsive poly(2-(2-ethoxyethoxy) ethyl acrylate-co-2-(2-methoxyethoxy) ethyl methacrylate) (P(Et2A-Me2MA)) through adhesion and detachment by incubation under a lower critical solution temperature of P(Et2A-Me2MA). A P(Et2A-Me2MA)-coated substrate is dissolved by incubation under 15 °C. A P(Et2A-Me2MA)-coated substrate can suppress platelet adhesion whereas it allows the cancer cells to adhere by an epithelial cell adhesion molecule (EpCAM) expression-independent mechanism. These results suggest that cancer cells can specifically adhere to a P(Et2A-Me2MA)-coated substrate, which can be used to isolate CTCs from peripheral blood. Moreover, approximately 90% of the adherent cells can be detached by incubation at 10 and 15 °C for 30 and 90 min, respectively. The collected cells can be cultured healthily in the presence of dissolved P(Et2A-Me2MA), suggesting that the cytotoxicity of P(Et2A-Me2MA) is low. In conclusion, P(Et2A-Me2MA) is suitable for the development of devices that collect intact CTCs via an adhesion-based method..
147. Takashi Hoshiba, Guoping Chen, Chiho Endo, Hiroka Maruyama, Miyuki Wakui, Eri Nemoto, Naoki Kawazoe, Masaru Tanaka, Decellularized extracellular matrix as an in vitro model to study the comprehensive roles of the ECM in stem cell differentiation, Stem Cells International, 10.1155/2016/6397820, 2016, 2016.01, Stem cells are a promising cell source for regenerative medicine. Stem cell differentiation must be regulated for applications in regenerative medicine. Stem cells are surrounded by extracellular matrix (ECM) in vivo. The ECM is composed of many types of proteins and glycosaminoglycans that assemble into a complex structure. The assembly of ECM molecules influences stem cell differentiation through orchestrated intracellular signaling activated by many ECM molecules. Therefore, it is important to understand the comprehensive role of the ECM in stem cell differentiation as well as the functions of the individual ECM molecules. Decellularized ECM is a useful in vitro model for studying the comprehensive roles of ECM because it retains a native-like structure and composition. Decellularized ECM can be obtained from in vivo tissue ECM or ECM fabricated by cells cultured in vitro. It is important to select the correct decellularized ECM because each type has different properties. In this review, tissue-derived and cell-derived decellularized ECMs are compared as in vitro ECM models to examine the comprehensive roles of the ECM in stem cell differentiation. We also summarize recent studies using decellularized ECM to determine the comprehensive roles of the ECM in stem cell differentiation..
148. Masaru Tanaka, Design Concept of Dialyzer Biomaterials
How to Find Biocompatible Polymers Based on the Biointerfacial Water Structure, Contributions to Nephrology, 10.1159/000451043, 189, 137-143, 2016.01, Background: Although various types of materials have been used widely in dialyzers, most biomaterials lack the desired functional properties to interface with blood and have not been engineered for optimum performance. Therefore, there is increasing demand to develop novel materials to address such problems in the dialysis arena. Numerous parameters of polymeric biomaterials can affect biocompatibility in a controlled manner. The mechanisms responsible for the biocompatibility of polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to try and understand them. Moreover, water interactions have been recognized as fundamental for the blood response to contact with polymers. Summary: We have proposed the 'intermediate water' concept and hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or nonfreezing water on the polymer surface, plays an important role in the biocompatibility of polymers. This chapter provides an overview of the recent experimental progress of biocompatible polymers measured by thermal, spectroscopic, and surface force techniques. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for dialyzers and provides an overview of the progress made in the design of multifunctional biomedical polymers by controlling the biointerfacial water structure through precision polymer synthesis. Key Messages: Intermediate water was found only in hydrated biopolymers (proteins, polysaccharides, and nucleic acids, DNA and RNA) and hydrated biocompatible synthetic polymers. Intermediate water could be one of the main screening factors for the design of appropriate dialyzer materials..
149. Takashi Hoshiba, Masaru Tanaka, Integrin-independent cell adhesion substrates
Possibility of applications for mechanobiology research, Analytical Sciences, 10.2116/analsci.32.1151, 32, 11, 1151-1158, 2016.01, Cells can mainly sense mechanical cues from the extracellular matrix via integrins. Because mechanical cues can strongly influence cellular functions, understanding the roles of integrins in the sensing of mechanical cues is a key for the achievement of tissue engineering. The analyses to determine the roles of integrins in the sensing of mechanical cues have been performed by many methods based on molecular- and cell-biological techniques, atomic force microscopy, and optical tweezers. Integrin-dependent cell adhesion substrates have been also used for this purpose. Additionally, the cells can adhere on several substrates via integrin-independent mechanisms. There are two types of integrin-independent cell adhesion substrates; 1) the substrates immobilized with ligands against the receptors on cell surface and 2) the substrates suppressing protein adsorption. Cells can exhibit specific functions on these substrates. Here, the examples of integrinindependent cell adhesion substrates were reviewed, and their possible applications in mechanobiology research are discussed..
150. Takashi Hoshiba, Toshihiko Orui, Chiho Endo, Kazuhiro Sato, Ayano Yoshihiro, Yasuhisa Minagawa, Masaru Tanaka, Adhesion-based simple capture and recovery of circulating tumor cells using a blood-compatible and thermo-responsive polymer-coated substrate, RSC Advances, 10.1039/c6ra15229e, 6, 92, 89103-89112, 2016.01, Circulating tumor cells (CTCs) have been a focus of study for metastatic cancer diagnostics, in in vitro anti-cancer drug screening to decide the chemotherapeutic course, and cancer biology research. For these purposes, there have been efforts made to collect CTCs from the peripheral blood of cancer patients. Here, we explore the possibility of collecting CTCs using blood-compatible and thermo-responsive poly(2-(2-ethoxyethoxy) ethyl acrylate-co-2-(2-methoxyethoxy) ethyl methacrylate) (P(Et2A-Me2MA)) through adhesion and detachment by incubation under a lower critical solution temperature of P(Et2A-Me2MA). A P(Et2A-Me2MA)-coated substrate is dissolved by incubation under 15 °C. A P(Et2A-Me2MA)-coated substrate can suppress platelet adhesion whereas it allows the cancer cells to adhere by an epithelial cell adhesion molecule (EpCAM) expression-independent mechanism. These results suggest that cancer cells can specifically adhere to a P(Et2A-Me2MA)-coated substrate, which can be used to isolate CTCs from peripheral blood. Moreover, approximately 90% of the adherent cells can be detached by incubation at 10 and 15 °C for 30 and 90 min, respectively. The collected cells can be cultured healthily in the presence of dissolved P(Et2A-Me2MA), suggesting that the cytotoxicity of P(Et2A-Me2MA) is low. In conclusion, P(Et2A-Me2MA) is suitable for the development of devices that collect intact CTCs via an adhesion-based method..
151. Takashi Hoshiba, Guoping Chen, Chiho Endo, Hiroka Maruyama, Miyuki Wakui, Eri Nemoto, Naoki Kawazoe, Masaru Tanaka, Decellularized extracellular matrix as an in vitro model to study the comprehensive roles of the ECM in stem cell differentiation, Stem Cells International, 10.1155/2016/6397820, 2016, 2016.01, Stem cells are a promising cell source for regenerative medicine. Stem cell differentiation must be regulated for applications in regenerative medicine. Stem cells are surrounded by extracellular matrix (ECM) in vivo. The ECM is composed of many types of proteins and glycosaminoglycans that assemble into a complex structure. The assembly of ECM molecules influences stem cell differentiation through orchestrated intracellular signaling activated by many ECM molecules. Therefore, it is important to understand the comprehensive role of the ECM in stem cell differentiation as well as the functions of the individual ECM molecules. Decellularized ECM is a useful in vitro model for studying the comprehensive roles of ECM because it retains a native-like structure and composition. Decellularized ECM can be obtained from in vivo tissue ECM or ECM fabricated by cells cultured in vitro. It is important to select the correct decellularized ECM because each type has different properties. In this review, tissue-derived and cell-derived decellularized ECMs are compared as in vitro ECM models to examine the comprehensive roles of the ECM in stem cell differentiation. We also summarize recent studies using decellularized ECM to determine the comprehensive roles of the ECM in stem cell differentiation..
152. Takashi Hoshiba, Masaru Tanaka, Integrin-independent cell adhesion substrates
Possibility of applications for mechanobiology research, Analytical Sciences, 10.2116/analsci.32.1151, 32, 11, 1151-1158, 2016.01, Cells can mainly sense mechanical cues from the extracellular matrix via integrins. Because mechanical cues can strongly influence cellular functions, understanding the roles of integrins in the sensing of mechanical cues is a key for the achievement of tissue engineering. The analyses to determine the roles of integrins in the sensing of mechanical cues have been performed by many methods based on molecular- and cell-biological techniques, atomic force microscopy, and optical tweezers. Integrin-dependent cell adhesion substrates have been also used for this purpose. Additionally, the cells can adhere on several substrates via integrin-independent mechanisms. There are two types of integrin-independent cell adhesion substrates; 1) the substrates immobilized with ligands against the receptors on cell surface and 2) the substrates suppressing protein adsorption. Cells can exhibit specific functions on these substrates. Here, the examples of integrinindependent cell adhesion substrates were reviewed, and their possible applications in mechanobiology research are discussed..
153. Takashi Hoshiba, Toshihiko Orui, Chiho Endo, Kazuhiro Sato, Ayano Yoshihiro, Yasuhisa Minagawa, Masaru Tanaka, Adhesion-based simple capture and recovery of circulating tumor cells using a blood-compatible and thermo-responsive polymer-coated substrate, RSC Advances, 10.1039/c6ra15229e, 6, 92, 89103-89112, 2016.01, Circulating tumor cells (CTCs) have been a focus of study for metastatic cancer diagnostics, in in vitro anti-cancer drug screening to decide the chemotherapeutic course, and cancer biology research. For these purposes, there have been efforts made to collect CTCs from the peripheral blood of cancer patients. Here, we explore the possibility of collecting CTCs using blood-compatible and thermo-responsive poly(2-(2-ethoxyethoxy) ethyl acrylate-co-2-(2-methoxyethoxy) ethyl methacrylate) (P(Et2A-Me2MA)) through adhesion and detachment by incubation under a lower critical solution temperature of P(Et2A-Me2MA). A P(Et2A-Me2MA)-coated substrate is dissolved by incubation under 15 °C. A P(Et2A-Me2MA)-coated substrate can suppress platelet adhesion whereas it allows the cancer cells to adhere by an epithelial cell adhesion molecule (EpCAM) expression-independent mechanism. These results suggest that cancer cells can specifically adhere to a P(Et2A-Me2MA)-coated substrate, which can be used to isolate CTCs from peripheral blood. Moreover, approximately 90% of the adherent cells can be detached by incubation at 10 and 15 °C for 30 and 90 min, respectively. The collected cells can be cultured healthily in the presence of dissolved P(Et2A-Me2MA), suggesting that the cytotoxicity of P(Et2A-Me2MA) is low. In conclusion, P(Et2A-Me2MA) is suitable for the development of devices that collect intact CTCs via an adhesion-based method..
154. Takashi Hoshiba, Guoping Chen, Chiho Endo, Hiroka Maruyama, Miyuki Wakui, Eri Nemoto, Naoki Kawazoe, Masaru Tanaka, Decellularized extracellular matrix as an in vitro model to study the comprehensive roles of the ECM in stem cell differentiation, Stem Cells International, 10.1155/2016/6397820, 2016, 2016.01, Stem cells are a promising cell source for regenerative medicine. Stem cell differentiation must be regulated for applications in regenerative medicine. Stem cells are surrounded by extracellular matrix (ECM) in vivo. The ECM is composed of many types of proteins and glycosaminoglycans that assemble into a complex structure. The assembly of ECM molecules influences stem cell differentiation through orchestrated intracellular signaling activated by many ECM molecules. Therefore, it is important to understand the comprehensive role of the ECM in stem cell differentiation as well as the functions of the individual ECM molecules. Decellularized ECM is a useful in vitro model for studying the comprehensive roles of ECM because it retains a native-like structure and composition. Decellularized ECM can be obtained from in vivo tissue ECM or ECM fabricated by cells cultured in vitro. It is important to select the correct decellularized ECM because each type has different properties. In this review, tissue-derived and cell-derived decellularized ECMs are compared as in vitro ECM models to examine the comprehensive roles of the ECM in stem cell differentiation. We also summarize recent studies using decellularized ECM to determine the comprehensive roles of the ECM in stem cell differentiation..
155. Takashi Hoshiba, Masaru Tanaka, Integrin-independent cell adhesion substrates
Possibility of applications for mechanobiology research, Analytical Sciences, 10.2116/analsci.32.1151, 32, 11, 1151-1158, 2016.01, Cells can mainly sense mechanical cues from the extracellular matrix via integrins. Because mechanical cues can strongly influence cellular functions, understanding the roles of integrins in the sensing of mechanical cues is a key for the achievement of tissue engineering. The analyses to determine the roles of integrins in the sensing of mechanical cues have been performed by many methods based on molecular- and cell-biological techniques, atomic force microscopy, and optical tweezers. Integrin-dependent cell adhesion substrates have been also used for this purpose. Additionally, the cells can adhere on several substrates via integrin-independent mechanisms. There are two types of integrin-independent cell adhesion substrates; 1) the substrates immobilized with ligands against the receptors on cell surface and 2) the substrates suppressing protein adsorption. Cells can exhibit specific functions on these substrates. Here, the examples of integrinindependent cell adhesion substrates were reviewed, and their possible applications in mechanobiology research are discussed..
156. Takashi Hoshiba, Masaru Tanaka, Decellularized extracellular matrix (ECM) as an in vitro model to study the comprehensive roles of the ECM in stem cell differentiation, Stem Cells International, 2016, 2016, 2016.
157. Masaru Tanaka, Difference in cell proliferation and spontaneous mediator release between two mast cell lines, NCL-2 and RBL-2H3 on honeycomb-like structured film, HSOA Journal of Nanotechnology: Nanomedicine & Nanobiotechnology, 3, 009, 2016.
158. Takashi Hoshiba, Masaru Tanaka, Integrin-independent cell adhesion substrates:Possibility of applications for mechanobiology research, Analytical Sciences, 32, 1151, 2016.
159. Takashi Hoshiba, Masaru Tanaka, Decellularized extracellular matrix (ECM) as an in vitro model to study the comprehensive roles of the ECM in stem cell differentiation, Stem Cells International, 2016, 2016, 2016.
160. Masaru Tanaka, Difference in cell proliferation and spontaneous mediator release between two mast cell lines, NCL-2 and RBL-2H3 on honeycomb-like structured film, HSOA Journal of Nanotechnology: Nanomedicine & Nanobiotechnology, 3, 009, 2016.
161. Takashi Hoshiba, Masaru Tanaka, Integrin-independent cell adhesion substrates:Possibility of applications for mechanobiology research, Analytical Sciences, 32, 1151, 2016.
162. Takashi Hoshiba, Masaru Tanaka, Decellularized extracellular matrix (ECM) as an in vitro model to study the comprehensive roles of the ECM in stem cell differentiation, Stem Cells International, 2016, 2016, 2016.
163. Masaru Tanaka, Difference in cell proliferation and spontaneous mediator release between two mast cell lines, NCL-2 and RBL-2H3 on honeycomb-like structured film, HSOA Journal of Nanotechnology: Nanomedicine & Nanobiotechnology, 3, 009, 2016.
164. Takashi Hoshiba, Masaru Tanaka, Integrin-independent cell adhesion substrates:Possibility of applications for mechanobiology research, Analytical Sciences, 32, 1151, 2016.
165. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Construction of a blood-compatible interface based on surface segregation in a polymer blend, Polymer, 10.1016/j.polymer.2015.10.001, 78, 219-224, 2015.11, The technique of surface segregation was applied to prepare a bio-inert polymer interface. A small amount, 10 wt%, of poly(2-methoxyethyl acrylate) (PMEA), which exhibits excellent bio-inertness properties, fed into a matrix polymer was able to suppress platelet adhesion sufficiently to be of practical use. PMEA was effective because it was preferentially segregated at the outermost region of the polymer blend. Combining interfacial-sensitive analyses such as the air bubble contact angle and neutron reflectivity measurements and sum-frequency generation spectroscopy with the platelet adhesion test gives a better understanding of how the bio-inert property is expressed at the water interface..
166. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Construction of a blood-compatible interface based on surface segregation in a polymer blend, Polymer, 10.1016/j.polymer.2015.10.001, 78, 219-224, 2015.11, The technique of surface segregation was applied to prepare a bio-inert polymer interface. A small amount, 10 wt%, of poly(2-methoxyethyl acrylate) (PMEA), which exhibits excellent bio-inertness properties, fed into a matrix polymer was able to suppress platelet adhesion sufficiently to be of practical use. PMEA was effective because it was preferentially segregated at the outermost region of the polymer blend. Combining interfacial-sensitive analyses such as the air bubble contact angle and neutron reflectivity measurements and sum-frequency generation spectroscopy with the platelet adhesion test gives a better understanding of how the bio-inert property is expressed at the water interface..
167. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Construction of a blood-compatible interface based on surface segregation in a polymer blend, polymer, 10.1016/j.polymer.2015.10.001, 78, 219-224, 2015.11, The technique of surface segregation was applied to prepare a bio-inert polymer interface. A small amount, 10 wt%, of poly(2-methoxyethyl acrylate) (PMEA), which exhibits excellent bio-inertness properties, fed into a matrix polymer was able to suppress platelet adhesion sufficiently to be of practical use. PMEA was effective because it was preferentially segregated at the outermost region of the polymer blend. Combining interfacial-sensitive analyses such as the air bubble contact angle and neutron reflectivity measurements and sum-frequency generation spectroscopy with the platelet adhesion test gives a better understanding of how the bio-inert property is expressed at the water interface..
168. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Construction of a blood-compatible interface based on surface segregation in a polymer blend, POLYMER, 10.1016/j.polymer.2015.10.001, 78, 219-224, 2015.11, The technique of surface segregation was applied to prepare a bio-inert polymer interface. A small amount, 10 wt%, of poly(2-methoxyethyl acrylate) (PMEA), which exhibits excellent bio-inertness properties, fed into a matrix polymer was able to suppress platelet adhesion sufficiently to be of practical use. PMEA was effective because it was preferentially segregated at the outermost region of the polymer blend. Combining interfacial-sensitive analyses such as the air bubble contact angle and neutron reflectivity measurements and sum-frequency generation spectroscopy with the platelet adhesion test gives a better understanding of how the bio-inert property is expressed at the water interface. (C) 2015 Elsevier Ltd. All rights reserved..
169. Kazuhiro Sato, Shingo Kobayashi, Miho Kusakari, Shogo Watahiki, Masahiko Oikawa, Takashi Hoshiba, Masaru Tanaka, The Relationship between Water Structure and Blood Compatibility in Poly(2-methoxyethyl Acrylate) (PMEA) Analogues, Macromolecular Bioscience, 10.1002/mabi.201500078, 15, 9, 1296-1303, 2015.09, Six types of poly(2-methoxyethyl acrylate) (PMEA) analogues were synthesized and the water structure in the hydrated polymers was characterized using differential scanning calorimetry (DSC). The hydrated PMEA analogues exhibited the different amounts of intermediate water. Non-thrombogenicity evaluation was performed on PMEA analogues for platelet adhesion and protein adsorption. Platelet adhesion was suppressed on PMEA analogues. In addition, the protein adsorption and deformation were suppressed by increasing the amount of intermediate water. This study demonstrates that the amount of intermediate water might play a key role in expressing the blood compatibility of polymeric materials..
170. Kazuhiro Sato, Shingo Kobayashi, Miho Kusakari, Shogo Watahiki, Masahiko Oikawa, Takashi Hoshiba, Masaru Tanaka, The Relationship between Water Structure and Blood Compatibility in Poly(2-methoxyethyl Acrylate) (PMEA) Analogues, Macromolecular Bioscience, 10.1002/mabi.201500078, 15, 9, 1296-1303, 2015.09, Six types of poly(2-methoxyethyl acrylate) (PMEA) analogues were synthesized and the water structure in the hydrated polymers was characterized using differential scanning calorimetry (DSC). The hydrated PMEA analogues exhibited the different amounts of intermediate water. Non-thrombogenicity evaluation was performed on PMEA analogues for platelet adhesion and protein adsorption. Platelet adhesion was suppressed on PMEA analogues. In addition, the protein adsorption and deformation were suppressed by increasing the amount of intermediate water. This study demonstrates that the amount of intermediate water might play a key role in expressing the blood compatibility of polymeric materials..
171. Kazuhiro Sato, Shingo Kobayashi, Miho Kusakari, Shogo Watahiki, Masahiko Oikawa, Takashi Hoshiba, Masaru Tanaka, The Relationship between Water Structure and Blood Compatibility in Poly(2-methoxyethyl Acrylate) (PMEA) Analogues, Macromolecular Bioscience, 10.1002/mabi.201500078, 15, 9, 1296-1303, 2015.09, Six types of poly(2-methoxyethyl acrylate) (PMEA) analogues were synthesized and the water structure in the hydrated polymers was characterized using differential scanning calorimetry (DSC). The hydrated PMEA analogues exhibited the different amounts of intermediate water. Non-thrombogenicity evaluation was performed on PMEA analogues for platelet adhesion and protein adsorption. Platelet adhesion was suppressed on PMEA analogues. In addition, the protein adsorption and deformation were suppressed by increasing the amount of intermediate water. This study demonstrates that the amount of intermediate water might play a key role in expressing the blood compatibility of polymeric materials..
172. Kazuhiro Sato, Shingo Kobayashi, Miho Kusakari, Shogo Watahiki, Masahiko Oikawa, Takashi Hoshiba, Masaru Tanaka, The Relationship Between Water Structure and Blood Compatibility in Poly(2-methoxyethyl Acrylate) (PMEA) Analogues, MACROMOLECULAR BIOSCIENCE, 10.1002/mabi.201500078, 15, 9, 1296-1303, 2015.09, Six types of poly(2-methoxyethyl acrylate) (PMEA) analogues were synthesized and the water structure in the hydrated polymers was characterized using differential scanning calorimetry (DSC). The hydrated PMEA analogues exhibited the different amounts of intermediate water. Non-thrombogenicity evaluation was performed on PMEA analogues for platelet adhesion and protein adsorption. Platelet adhesion was suppressed on PMEA analogues. In addition, the protein adsorption and deformation were suppressed by increasing the amount of intermediate water. This study demonstrates that the amount of intermediate water might play a key role in expressing the blood compatibility of polymeric materials..
173. Takashi Hoshiba, Takayuki Otaki, Eri Nemoto, Hiroka Maruyama, Masaru Tanaka, Blood-Compatible Polymer for Hepatocyte Culture with High Hepatocyte-Specific Functions toward Bioartificial Liver Development, ACS applied materials & interfaces, 10.1021/acsami.5b05210, 7, 32, 18096-18103, 2015.08, The development of bioartificial liver (BAL) is expected because of the shortage of donor liver for transplantation. The substrates for BAL require the following criteria: (a) blood compatibility, (b) hepatocyte adhesiveness, and (c) the ability to maintain hepatocyte-specific functions. Here, we examined blood-compatible poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) (PTHFA) as the substrates for BAL. HepG2, a human hepatocyte model, could adhere on PMEA and PTHFA substrates. The spreading of HepG2 cells was suppressed on PMEA substrates because integrin contribution to cell adhesion on PMEA substrate was low and integrin signaling was not sufficiently activated. Hepatocyte-specific gene expression in HepG2 cells increased on PMEA substrate, whereas the expression decreased on PTHFA substrates due to the nuclear localization of Yes-associated protein (YAP). These results indicate that blood-compatible PMEA is suitable for BAL substrate. Also, PMEA is expected to be used to regulate cell functions for blood-contacting tissue engineering..
174. Ferdous Khan, Masaru Tanaka, Sheikh Rafi Ahmad, Fabrication of polymeric biomaterials
a strategy for tissue engineering and medical devices, Journal of Materials Chemistry B, 10.1039/c5tb01370d, 3, 42, 8224-8249, 2015.08, Polymeric biomaterials have a significant impact in today's health care technology. Polymer hydrogels were the first experimentally designed biomaterials for human use. In this article the design, synthesis and properties of hydrogels, derived from synthetic and natural polymers, and their use as biomaterials in tissue engineering are reviewed. The stimuli-responsive hydrogels with controlled degradability and examples of suitable methods for designing such biomaterials, using multidisciplinary approaches from traditional polymer chemistry, materials engineering to molecular biology, have been discussed. Examples of the fabrication of polymer-based biomaterials, utilized for various cell type manipulations for tissue re-generation are also elaborated. Since a highly porous three-dimensional scaffold is crucially important in the cellular process, for tissue engineering, recent advances in the effective methods of scaffold fabrication are described. Additionally, the incorporation of factor molecules for the enhancement of tissue formation and their controlled release is also elucidated in this article. Finally, the future challenges in the efficient fabrication of effective polymeric biomaterials for tissue regeneration and medical device applications are discussed..
175. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Toshihiko Orui, Takayuki Otaki, Ayano Yoshihiro, Masaru Tanaka, Regulation of the contribution of integrin to Cell attachment on poly(2-methoxyethyl acrylate) (PMEA) analogous polymers for attachment-based cell enrichment, PLoS One, 10.1371/journal.pone.0136066, 10, 8, 2015.08, Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate) (PBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA), on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe2A) and poly(2-(2-methoxyethoxy) ethoxy ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe3A), which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment..
176. Takashi Hoshiba, Takayuki Otaki, Eri Nemoto, Hiroka Maruyama, Masaru Tanaka, Blood-Compatible Polymer for Hepatocyte Culture with High Hepatocyte-Specific Functions toward Bioartificial Liver Development, ACS Applied Materials and Interfaces, 10.1021/acsami.5b05210, 7, 32, 18096-18103, 2015.08, The development of bioartificial liver (BAL) is expected because of the shortage of donor liver for transplantation. The substrates for BAL require the following criteria: (a) blood compatibility, (b) hepatocyte adhesiveness, and (c) the ability to maintain hepatocyte-specific functions. Here, we examined blood-compatible poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) (PTHFA) as the substrates for BAL. HepG2, a human hepatocyte model, could adhere on PMEA and PTHFA substrates. The spreading of HepG2 cells was suppressed on PMEA substrates because integrin contribution to cell adhesion on PMEA substrate was low and integrin signaling was not sufficiently activated. Hepatocyte-specific gene expression in HepG2 cells increased on PMEA substrate, whereas the expression decreased on PTHFA substrates due to the nuclear localization of Yes-associated protein (YAP). These results indicate that blood-compatible PMEA is suitable for BAL substrate. Also, PMEA is expected to be used to regulate cell functions for blood-contacting tissue engineering..
177. Ferdous Khan, Masaru Tanaka, Sheikh Rafi Ahmad, Fabrication of polymeric biomaterials
a strategy for tissue engineering and medical devices, Journal of Materials Chemistry B, 10.1039/c5tb01370d, 3, 42, 8224-8249, 2015.08, Polymeric biomaterials have a significant impact in today's health care technology. Polymer hydrogels were the first experimentally designed biomaterials for human use. In this article the design, synthesis and properties of hydrogels, derived from synthetic and natural polymers, and their use as biomaterials in tissue engineering are reviewed. The stimuli-responsive hydrogels with controlled degradability and examples of suitable methods for designing such biomaterials, using multidisciplinary approaches from traditional polymer chemistry, materials engineering to molecular biology, have been discussed. Examples of the fabrication of polymer-based biomaterials, utilized for various cell type manipulations for tissue re-generation are also elaborated. Since a highly porous three-dimensional scaffold is crucially important in the cellular process, for tissue engineering, recent advances in the effective methods of scaffold fabrication are described. Additionally, the incorporation of factor molecules for the enhancement of tissue formation and their controlled release is also elucidated in this article. Finally, the future challenges in the efficient fabrication of effective polymeric biomaterials for tissue regeneration and medical device applications are discussed..
178. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Toshihiko Orui, Takayuki Otaki, Ayano Yoshihiro, Masaru Tanaka, Regulation of the contribution of integrin to Cell attachment on poly(2-methoxyethyl acrylate) (PMEA) analogous polymers for attachment-based cell enrichment, PLoS One, 10.1371/journal.pone.0136066, 10, 8, 2015.08, Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate) (PBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA), on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe2A) and poly(2-(2-methoxyethoxy) ethoxy ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe3A), which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment..
179. Takashi Hoshiba, Takayuki Otaki, Eri Nemoto, Hiroka Maruyama, Masaru Tanaka, Blood-Compatible Polymer for Hepatocyte Culture with High Hepatocyte-Specific Functions toward Bioartificial Liver Development, ACS Applied Materials and Interfaces, 10.1021/acsami.5b05210, 7, 32, 18096-18103, 2015.08, The development of bioartificial liver (BAL) is expected because of the shortage of donor liver for transplantation. The substrates for BAL require the following criteria: (a) blood compatibility, (b) hepatocyte adhesiveness, and (c) the ability to maintain hepatocyte-specific functions. Here, we examined blood-compatible poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) (PTHFA) as the substrates for BAL. HepG2, a human hepatocyte model, could adhere on PMEA and PTHFA substrates. The spreading of HepG2 cells was suppressed on PMEA substrates because integrin contribution to cell adhesion on PMEA substrate was low and integrin signaling was not sufficiently activated. Hepatocyte-specific gene expression in HepG2 cells increased on PMEA substrate, whereas the expression decreased on PTHFA substrates due to the nuclear localization of Yes-associated protein (YAP). These results indicate that blood-compatible PMEA is suitable for BAL substrate. Also, PMEA is expected to be used to regulate cell functions for blood-contacting tissue engineering..
180. Ferdous Khan, Masaru Tanaka, Sheikh Rafi Ahmad, Fabrication of polymeric biomaterials
a strategy for tissue engineering and medical devices, Journal of Materials Chemistry B, 10.1039/c5tb01370d, 3, 42, 8224-8249, 2015.08, Polymeric biomaterials have a significant impact in today's health care technology. Polymer hydrogels were the first experimentally designed biomaterials for human use. In this article the design, synthesis and properties of hydrogels, derived from synthetic and natural polymers, and their use as biomaterials in tissue engineering are reviewed. The stimuli-responsive hydrogels with controlled degradability and examples of suitable methods for designing such biomaterials, using multidisciplinary approaches from traditional polymer chemistry, materials engineering to molecular biology, have been discussed. Examples of the fabrication of polymer-based biomaterials, utilized for various cell type manipulations for tissue re-generation are also elaborated. Since a highly porous three-dimensional scaffold is crucially important in the cellular process, for tissue engineering, recent advances in the effective methods of scaffold fabrication are described. Additionally, the incorporation of factor molecules for the enhancement of tissue formation and their controlled release is also elucidated in this article. Finally, the future challenges in the efficient fabrication of effective polymeric biomaterials for tissue regeneration and medical device applications are discussed..
181. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Toshihiko Orui, Takayuki Otaki, Ayano Yoshihiro, Masaru Tanaka, Regulation of the contribution of integrin to Cell attachment on poly(2-methoxyethyl acrylate) (PMEA) analogous polymers for attachment-based cell enrichment, PloS one, 10.1371/journal.pone.0136066, 10, 8, 2015.08, Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate) (PBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA), on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe2A) and poly(2-(2-methoxyethoxy) ethoxy ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe3A), which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment..
182. Takashi Hoshiba, Takayuki Otaki, Eri Nemoto, Hiroka Maruyama, Masaru Tanaka, Blood-Compatible Polymer for Hepatocyte Culture with High Hepatocyte-Specific Functions toward Bioartificial Liver Development, ACS APPLIED MATERIALS & INTERFACES, 10.1021/acsami.5b05210, 7, 32, 18096-18103, 2015.08, The development of bioartificial liver (BAL) is expected because of the shortage of donor liver for transplantation. The substrates for BAL require the following criteria: (a) blood compatibility, (b) hepatocyte adhesiveness, and (c) the ability to maintain hepatocyte-specific functions. Here, we examined blood-compatible poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) (PTHFA) as the substrates for BAL. HepG2, a human hepatocyte model, could adhere on PMEA and PTHFA substrates. The spreading of HepG2 cells was suppressed on PMEA substrates because integrin contribution to cell adhesion on PMEA substrate was low and integrin signaling was not sufficiently activated. Hepatocyte-specific gene expression in HepG2 cells increased on PMEA substrate, whereas the expression decreased on PTHFA substrates due to the nuclear localization of Yes-associated protein (YAP). These results indicate that blood-compatible PMEA is suitable for BAL substrate. Also, PMEA is expected to be used to regulate cell functions for blood-contacting tissue engineering..
183. Takashi Hoshiba, Eri Nemoto, Kazuhiro Sato, Toshihiko Orui, Takayuki Otaki, Ayano Yoshihiro, Masaru Tanaka, Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate) (PMEA) Analogous Polymers for Attachment-Based Cell Enrichment, PLOS ONE, 10.1371/journal.pone.0136066, 10, 8, 2015.08, Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate) (PBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA), on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe2A) and poly(2-(2-methoxyethoxy) ethoxy ethyl acrylate-co-butyl acrylate) (30: 70 mol%, PMe3A), which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment..
184. T. Hirata, Hisao Matsuno, Daisuke Kawaguchi, N. L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of interfacial structure on bioinert properties of poly(2-methoxyethyl acrylate)/poly(methyl methacrylate) blend films in water, Physical Chemistry Chemical Physics, 10.1039/c5cp01972a, 17, 26, 17399-17405, 2015.07, In this study, we found that the surface made of a mixture of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) (PMMA) exhibited excellent blood compatibility by inhibiting platelet adhesion. To obtain a better understanding of this bioinertness, the polymer/water interface was characterized by neutron reflectivity measurements and sum frequency generation spectroscopy, in conjunction with bubble contact angle measurements. Based on the results, we can say that the outermost region of the blend film was reorganized in water. When the orientation of PMEA segments at the water interface became random with increasing immersion time, the fractional amount of lower-coordinated water molecules increased at the interface. Such an interfacial structure caused the suppression of platelet adhesion..
185. Kazuki Fukushima, Meng Yu Tsai, Takayuki Ota, Yuta Haga, Kodai Matsuzaki, Yuto Inoue, Masaru Tanaka, Evaluation of the hemocompatibility of hydrated biodegradable aliphatic carbonyl polymers with a subtle difference in the backbone structure based on the intermediate water concept and surface hydration, Polymer Journal, 10.1038/pj.2015.22, 47, 7, 469-473, 2015.07, The hydration behavior, intermediate water content and platelet adhesion level of poly(trimethylene carbonate) (PTMC) and three other aliphatic carbonyl polymers (PDO, PCL and poly(δ -valerolactone) (PVL))was investigated to elucidate the influence of subtle differences in the backbone structure on hydration and hemocompatibility. PTMC and PVL were synthesized and used as DSC specimens. A spin-coated surface was used for the platelet adhesion test and contact angle measurements. The cast coatings and films were used for the infrared spectroscopy (IR). All hydrated surfaces and films were prepared by immersion in deionized water for 24 h. The phase transitions of water in the hydrated polymers were measured using DSC. The overall water content in the polymer was determined. The roughness of the spin-coated surfaces was evaluated using atomic force microscopy. The static contact angles of the polymer surface against water were measured using both a sessile drop and a captive bubble. By investigating the differences in hydration behavior of the polymer backbones with ester and carbonate bonds, we found that the carbonate bonds favor conformational change compared with ester bonds because of their stronger capacities as hydrogen bond acceptors and the less-regulated C=O on the surface based on its amorphous nature..
186. T. Hirata, Hisao Matsuno, Daisuke Kawaguchi, N. L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of interfacial structure on bioinert properties of poly(2-methoxyethyl acrylate)/poly(methyl methacrylate) blend films in water, Physical Chemistry Chemical Physics, 10.1039/c5cp01972a, 17, 26, 17399-17405, 2015.07, In this study, we found that the surface made of a mixture of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) (PMMA) exhibited excellent blood compatibility by inhibiting platelet adhesion. To obtain a better understanding of this bioinertness, the polymer/water interface was characterized by neutron reflectivity measurements and sum frequency generation spectroscopy, in conjunction with bubble contact angle measurements. Based on the results, we can say that the outermost region of the blend film was reorganized in water. When the orientation of PMEA segments at the water interface became random with increasing immersion time, the fractional amount of lower-coordinated water molecules increased at the interface. Such an interfacial structure caused the suppression of platelet adhesion..
187. Kazuki Fukushima, Meng Yu Tsai, Takayuki Ota, Yuta Haga, Kodai Matsuzaki, Yuto Inoue, Masaru Tanaka, Evaluation of the hemocompatibility of hydrated biodegradable aliphatic carbonyl polymers with a subtle difference in the backbone structure based on the intermediate water concept and surface hydration, Polymer Journal, 10.1038/pj.2015.22, 47, 7, 469-473, 2015.07, The hydration behavior, intermediate water content and platelet adhesion level of poly(trimethylene carbonate) (PTMC) and three other aliphatic carbonyl polymers (PDO, PCL and poly(δ -valerolactone) (PVL))was investigated to elucidate the influence of subtle differences in the backbone structure on hydration and hemocompatibility. PTMC and PVL were synthesized and used as DSC specimens. A spin-coated surface was used for the platelet adhesion test and contact angle measurements. The cast coatings and films were used for the infrared spectroscopy (IR). All hydrated surfaces and films were prepared by immersion in deionized water for 24 h. The phase transitions of water in the hydrated polymers were measured using DSC. The overall water content in the polymer was determined. The roughness of the spin-coated surfaces was evaluated using atomic force microscopy. The static contact angles of the polymer surface against water were measured using both a sessile drop and a captive bubble. By investigating the differences in hydration behavior of the polymer backbones with ester and carbonate bonds, we found that the carbonate bonds favor conformational change compared with ester bonds because of their stronger capacities as hydrogen bond acceptors and the less-regulated C=O on the surface based on its amorphous nature..
188. T. Hirata, H. Matsuno, D. Kawaguchi, N. L. Yamada, M. Tanaka, K. Tanaka, Effect of interfacial structure on bioinert properties of poly(2-methoxyethyl acrylate)/poly(methyl methacrylate) blend films in water, Physical Chemistry Chemical Physics, 10.1039/c5cp01972a, 17, 26, 17399-17405, 2015.07, In this study, we found that the surface made of a mixture of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) (PMMA) exhibited excellent blood compatibility by inhibiting platelet adhesion. To obtain a better understanding of this bioinertness, the polymer/water interface was characterized by neutron reflectivity measurements and sum frequency generation spectroscopy, in conjunction with bubble contact angle measurements. Based on the results, we can say that the outermost region of the blend film was reorganized in water. When the orientation of PMEA segments at the water interface became random with increasing immersion time, the fractional amount of lower-coordinated water molecules increased at the interface. Such an interfacial structure caused the suppression of platelet adhesion..
189. Kazuki Fukushima, Meng Yu Tsai, Takayuki Ota, Yuta Haga, Kodai Matsuzaki, Yuto Inoue, Masaru Tanaka, Evaluation of the hemocompatibility of hydrated biodegradable aliphatic carbonyl polymers with a subtle difference in the backbone structure based on the intermediate water concept and surface hydration, Polymer Journal, 10.1038/pj.2015.22, 47, 7, 469-473, 2015.07, The hydration behavior, intermediate water content and platelet adhesion level of poly(trimethylene carbonate) (PTMC) and three other aliphatic carbonyl polymers (PDO, PCL and poly(δ -valerolactone) (PVL))was investigated to elucidate the influence of subtle differences in the backbone structure on hydration and hemocompatibility. PTMC and PVL were synthesized and used as DSC specimens. A spin-coated surface was used for the platelet adhesion test and contact angle measurements. The cast coatings and films were used for the infrared spectroscopy (IR). All hydrated surfaces and films were prepared by immersion in deionized water for 24 h. The phase transitions of water in the hydrated polymers were measured using DSC. The overall water content in the polymer was determined. The roughness of the spin-coated surfaces was evaluated using atomic force microscopy. The static contact angles of the polymer surface against water were measured using both a sessile drop and a captive bubble. By investigating the differences in hydration behavior of the polymer backbones with ester and carbonate bonds, we found that the carbonate bonds favor conformational change compared with ester bonds because of their stronger capacities as hydrogen bond acceptors and the less-regulated C=O on the surface based on its amorphous nature..
190. Kazuki Fukushima, Meng-Yu Tsai, Takayuki Ota, Yuta Haga, Kodai Matsuzaki, Yuto Inoue, Masaru Tanaka, Evaluation of the hemocompatibility of hydrated biodegradable aliphatic carbonyl polymers with a subtle difference in the backbone structure based on the intermediate water concept and surface hydration, POLYMER JOURNAL, 10.1038/pj.2015.22, 47, 7, 469-473, 2015.07.
191. Taito Sekine, Yusaku Tanaka, Chikako Sato, Masaru Tanaka, Tomohiro Hayashi, Evaluation of Factors To Determine Platelet Compatibility by Using Self-Assembled Monolayers with a Chemical Gradient, Langmuir, 10.1021/acs.langmuir.5b01216, 31, 25, 7100-7105, 2015.06, Intercorrelation among surface chemical composition, packing structure of molecules, water contact angles, amounts and structures of adsorbed proteins, and blood compatibility was systematically investigated with self-assembled monolayers (SAMs) with continuous chemical composition gradients. The SAMs were mixtures of two thiols: n-hexanethiol (hydrophobic and protein-adsorbing) and hydroxyl-tri(ethylene glycol)-terminated alkanethiol (hydrophilic and protein-resistant) with continuously changing mixing ratios. From the systematic analyses, we found that protein adsorption is governed both by sizes of proteins and hydrophobic domains of the substrate. Furthermore, we found a clear correlation between adsorption of fibrinogen and adhesion of platelets. Combined with the results of surface force measurements, we found that the interfacial behavior of water molecules is profoundly correlated with protein resistance and antiplatelet adhesion. On the basis of these results, we conclude that the structuring of water at the SAM-water interface is a critical factor in this context..
192. Taito Sekine, Yusaku Tanaka, Chikako Sato, Masaru Tanaka, Tomohiro Hayashi, Evaluation of Factors To Determine Platelet Compatibility by Using Self-Assembled Monolayers with a Chemical Gradient, Langmuir, 10.1021/acs.langmuir.5b01216, 31, 25, 7100-7105, 2015.06, Intercorrelation among surface chemical composition, packing structure of molecules, water contact angles, amounts and structures of adsorbed proteins, and blood compatibility was systematically investigated with self-assembled monolayers (SAMs) with continuous chemical composition gradients. The SAMs were mixtures of two thiols: n-hexanethiol (hydrophobic and protein-adsorbing) and hydroxyl-tri(ethylene glycol)-terminated alkanethiol (hydrophilic and protein-resistant) with continuously changing mixing ratios. From the systematic analyses, we found that protein adsorption is governed both by sizes of proteins and hydrophobic domains of the substrate. Furthermore, we found a clear correlation between adsorption of fibrinogen and adhesion of platelets. Combined with the results of surface force measurements, we found that the interfacial behavior of water molecules is profoundly correlated with protein resistance and antiplatelet adhesion. On the basis of these results, we conclude that the structuring of water at the SAM-water interface is a critical factor in this context..
193. Taito Sekine, Yusaku Tanaka, Chikako Sato, Masaru Tanaka, Tomohiro Hayashi, Evaluation of Factors To Determine Platelet Compatibility by Using Self-Assembled Monolayers with a Chemical Gradient, Langmuir, 10.1021/acs.langmuir.5b01216, 31, 25, 7100-7105, 2015.06, Intercorrelation among surface chemical composition, packing structure of molecules, water contact angles, amounts and structures of adsorbed proteins, and blood compatibility was systematically investigated with self-assembled monolayers (SAMs) with continuous chemical composition gradients. The SAMs were mixtures of two thiols: n-hexanethiol (hydrophobic and protein-adsorbing) and hydroxyl-tri(ethylene glycol)-terminated alkanethiol (hydrophilic and protein-resistant) with continuously changing mixing ratios. From the systematic analyses, we found that protein adsorption is governed both by sizes of proteins and hydrophobic domains of the substrate. Furthermore, we found a clear correlation between adsorption of fibrinogen and adhesion of platelets. Combined with the results of surface force measurements, we found that the interfacial behavior of water molecules is profoundly correlated with protein resistance and antiplatelet adhesion. On the basis of these results, we conclude that the structuring of water at the SAM-water interface is a critical factor in this context..
194. Taito Sekine, Yusaku Tanaka, Chikako Sato, Masaru Tanaka, Tomohiro Hayashi, Evaluation of Factors To Determine Platelet Compatibility by Using Self-Assembled Mono layers with a Chemical Gradient, LANGMUIR, 10.1021/acs.langmuir.5b01216, 31, 25, 7100-7105, 2015.06, Intercorrelation among surface chemical composition, packing structure of molecules, water contact angles, amounts and structures of adsorbed proteins, and blood compatibility was systematically investigated with self-assembled monolayers (SAMs) with continuous chemical composition gradients. The SAMs were mixtures of two thiols: n=hexanethiol (hydrophobic and protein-adsorbing) and hydroxyl-tri(ethylene glycol)-terminated alkanethiol (hydrophilic and protein-resistant) with continuously changing mixing ratios. From the systematic analyses, we found that protein adsorption is governed both by sizes of proteins and hydrophobic domains of the substrate, Furthermore, we found a clear correlation between adsorption of fibrinogen and adhesion of platelets. Combined with the results of surface force measurements, we found that the interfacial behavior of water molecules is profoundly correlated with protein resistance and antiplatelet adhesion. On the basis of these results, we conclude that the structuring of water at the SAM-water interface is a critical factor in this context..
195. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Tomoyasu Hirai, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of local chain dynamics on a bioinert interface, Langmuir, 10.1021/acs.langmuir.5b00258, 31, 12, 3661-3667, 2015.03, Although many kinds of synthetic polymers have been investigated to construct blood-compatible materials, only a few have achieved success. To establish molecular designs for blood-compatible polymers, the chain structure and dynamics at the water interface must be understood using solid evidence as the first bench mark. Here we show that polymer dynamics at the water interface impacts on structure of the interfacial water, resulting in a change in protein adsorption and of platelet adhesion. As a particular material, a blend composed of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) was used. PMEA was segregated to the water interface. While the local conformation of PMEA at the water interface was insensitive to its molecular weight, the local dynamics became faster with decreasing molecular weight, resulting in a disturbance of the network structure of waters at the interface. This leads to the extreme suppression of protein adsorption and platelet adhesion..
196. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Tomoyasu Hirai, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of local chain dynamics on a bioinert interface, Langmuir, 10.1021/acs.langmuir.5b00258, 31, 12, 3661-3667, 2015.03, Although many kinds of synthetic polymers have been investigated to construct blood-compatible materials, only a few have achieved success. To establish molecular designs for blood-compatible polymers, the chain structure and dynamics at the water interface must be understood using solid evidence as the first bench mark. Here we show that polymer dynamics at the water interface impacts on structure of the interfacial water, resulting in a change in protein adsorption and of platelet adhesion. As a particular material, a blend composed of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) was used. PMEA was segregated to the water interface. While the local conformation of PMEA at the water interface was insensitive to its molecular weight, the local dynamics became faster with decreasing molecular weight, resulting in a disturbance of the network structure of waters at the interface. This leads to the extreme suppression of protein adsorption and platelet adhesion..
197. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Tomoyasu Hirai, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of local chain dynamics on a bioinert interface, Langmuir, 10.1021/acs.langmuir.5b00258, 31, 12, 3661-3667, 2015.03, Although many kinds of synthetic polymers have been investigated to construct blood-compatible materials, only a few have achieved success. To establish molecular designs for blood-compatible polymers, the chain structure and dynamics at the water interface must be understood using solid evidence as the first bench mark. Here we show that polymer dynamics at the water interface impacts on structure of the interfacial water, resulting in a change in protein adsorption and of platelet adhesion. As a particular material, a blend composed of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) was used. PMEA was segregated to the water interface. While the local conformation of PMEA at the water interface was insensitive to its molecular weight, the local dynamics became faster with decreasing molecular weight, resulting in a disturbance of the network structure of waters at the interface. This leads to the extreme suppression of protein adsorption and platelet adhesion..
198. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Tomoyasu Hirai, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of Local Chain Dynamics on a Bioinert Interface, LANGMUIR, 10.1021/acs.langmuir.5b00258, 31, 12, 3661-3667, 2015.03, Although many kinds of synthetic polymers have been investigated to construct blood-compatible materials, only a few have achieved success. To establish molecular designs for blood-compatible polymers, the chain structure and dynamics at the water interface must be understood using solid evidence as the first bench mark. Here we show that polymer dynamics at the water interface impacts on structure of the interfacial water, resulting in a change in protein adsorption and of platelet adhesion. As a particular material, a blend composed of poly(2-methoxyethyl acrylate) (PMEA) and poly(methyl methacrylate) was used. PMEA was segregated to the water interface. While the local conformation of PMEA at the water interface was insensitive to its molecular weight, the local dynamics became faster with decreasing molecular weight, resulting in a disturbance of the network structure of waters at the interface. This leads to the extreme suppression of protein adsorption and platelet adhesion..
199. Takashi Hoshiba, Masaru Tanaka, Optimization of the tissue source, malignancy, and initial substrate of tumor cell-derived matrices to increase cancer cell chemoresistance against 5-fluorouracil, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2014.12.116, 457, 3, 353-357, 2015.02, The low chemoresistance of in vitro cancer cells inhibits the development of new anti-cancer drugs. Thus, development of a new in vitro culture system is required to increase the chemoresistance of in vitro cancer cells. Tumor cell-derived matrices have been reported to increase the chemoresistance of in vitro cancer cells. However, it remains unclear how tissue sources and the malignancy of cells used for the preparation of matrices affect the chemoresistance of tumor cell-derived matrices. Moreover, it remains unclear how the initial substrates used for the preparation of matrices affect the chemoresistance. In this study, we compared the effects of tissue sources and the malignancy of tumor cells, as well as the effect of the initial substrates on chemoresistance against 5-fluorouracil (5-FU). The chemoresistance of breast and colon cancer cells against 5-FU increased on matrices prepared with cells derived from the corresponding original tissues with higher malignancy. Moreover, the chemoresistance against 5-FU was altered on matrices prepared using different initial substrates that exhibited different characteristics of protein adsorption. Taken together, these results indicated that the appropriate selection of tissue sources, malignancy of tumor cells, and initial substrates used for matrix preparation is important for the preparation of tumor cell-derived matrices for chemoresistance assays..
200. Masaru Tanaka, Kazuhiro Sato, Erika Kitakami, Shingo Kobayashi, Takashi Hoshiba, Kazuki Fukushima, Design of biocompatible and biodegradable polymers based on intermediate water concept, Polymer Journal, 10.1038/pj.2014.129, 47, 2, 114-121, 2015.02, Polymeric biomaterials have significant impact in the aged society. Biocompatible and biodegradable polymers have emerged during the past decades to promise extraordinary breakthroughs in a wide range of diagnostic and therapeutic medical devices. Understanding and controlling the interfacial interactions of the polymeric biomaterials with biological elements, such as water, ions, proteins, bacteria, fungai and cells, are essential toward their successful implementation in biomedical applications. Here we highlight the recent developments of biocompatible and biodegradable fusion polymeric biomaterials for medical devices and provide an overview of the recent progress of the design of the multi-functional biomedical polymers by controlling bio-interfacial water structure through precision polymer synthesis and supramolecular chemistry..
201. Takashi Hoshiba, Masaru Tanaka, Optimization of the tissue source, malignancy, and initial substrate of tumor cell-derived matrices to increase cancer cell chemoresistance against 5-fluorouracil, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2014.12.116, 457, 3, 353-357, 2015.02, The low chemoresistance of in vitro cancer cells inhibits the development of new anti-cancer drugs. Thus, development of a new in vitro culture system is required to increase the chemoresistance of in vitro cancer cells. Tumor cell-derived matrices have been reported to increase the chemoresistance of in vitro cancer cells. However, it remains unclear how tissue sources and the malignancy of cells used for the preparation of matrices affect the chemoresistance of tumor cell-derived matrices. Moreover, it remains unclear how the initial substrates used for the preparation of matrices affect the chemoresistance. In this study, we compared the effects of tissue sources and the malignancy of tumor cells, as well as the effect of the initial substrates on chemoresistance against 5-fluorouracil (5-FU). The chemoresistance of breast and colon cancer cells against 5-FU increased on matrices prepared with cells derived from the corresponding original tissues with higher malignancy. Moreover, the chemoresistance against 5-FU was altered on matrices prepared using different initial substrates that exhibited different characteristics of protein adsorption. Taken together, these results indicated that the appropriate selection of tissue sources, malignancy of tumor cells, and initial substrates used for matrix preparation is important for the preparation of tumor cell-derived matrices for chemoresistance assays..
202. Masaru Tanaka, Kazuhiro Sato, Erika Kitakami, Shingo Kobayashi, Takashi Hoshiba, Kazuki Fukushima, Design of biocompatible and biodegradable polymers based on intermediate water concept, Polymer Journal, 10.1038/pj.2014.129, 47, 2, 114-121, 2015.02, Polymeric biomaterials have significant impact in the aged society. Biocompatible and biodegradable polymers have emerged during the past decades to promise extraordinary breakthroughs in a wide range of diagnostic and therapeutic medical devices. Understanding and controlling the interfacial interactions of the polymeric biomaterials with biological elements, such as water, ions, proteins, bacteria, fungai and cells, are essential toward their successful implementation in biomedical applications. Here we highlight the recent developments of biocompatible and biodegradable fusion polymeric biomaterials for medical devices and provide an overview of the recent progress of the design of the multi-functional biomedical polymers by controlling bio-interfacial water structure through precision polymer synthesis and supramolecular chemistry..
203. Takashi Hoshiba, Masaru Tanaka, Optimization of the tissue source, malignancy, and initial substrate of tumor cell-derived matrices to increase cancer cell chemoresistance against 5-fluorouracil, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2014.12.116, 457, 3, 353-357, 2015.02, The low chemoresistance of in vitro cancer cells inhibits the development of new anti-cancer drugs. Thus, development of a new in vitro culture system is required to increase the chemoresistance of in vitro cancer cells. Tumor cell-derived matrices have been reported to increase the chemoresistance of in vitro cancer cells. However, it remains unclear how tissue sources and the malignancy of cells used for the preparation of matrices affect the chemoresistance of tumor cell-derived matrices. Moreover, it remains unclear how the initial substrates used for the preparation of matrices affect the chemoresistance. In this study, we compared the effects of tissue sources and the malignancy of tumor cells, as well as the effect of the initial substrates on chemoresistance against 5-fluorouracil (5-FU). The chemoresistance of breast and colon cancer cells against 5-FU increased on matrices prepared with cells derived from the corresponding original tissues with higher malignancy. Moreover, the chemoresistance against 5-FU was altered on matrices prepared using different initial substrates that exhibited different characteristics of protein adsorption. Taken together, these results indicated that the appropriate selection of tissue sources, malignancy of tumor cells, and initial substrates used for matrix preparation is important for the preparation of tumor cell-derived matrices for chemoresistance assays..
204. Masaru Tanaka, Kazuhiro Sato, Erika Kitakami, Shingo Kobayashi, Takashi Hoshiba, Kazuki Fukushima, Design of biocompatible and biodegradable polymers based on intermediate water concept, POLYMER JOURNAL, 10.1038/pj.2014.129, 47, 2, 114-121, 2015.02, Polymeric biomaterials have significant impact in the aged society. Biocompatible and biodegradable polymers have emerged during the past decades to promise extraordinary breakthroughs in a wide range of diagnostic and therapeutic medical devices. Understanding and controlling the interfacial interactions of the polymeric biomaterials with biological elements, such as water, ions, proteins, bacteria, fungai and cells, are essential toward their successful implementation in biomedical applications. Here we highlight the recent developments of biocompatible and biodegradable fusion polymeric biomaterials for medical devices and provide an overview of the recent progress of the design of the multi-functional biomedical polymers by controlling bio-interfacial water structure through precision polymer synthesis and supramolecular chemistry..
205. Takashi Hoshiba, Masaru Tanaka, Optimization of the tissue source, malignancy, and initial substrate of tumor cell-derived matrices to increase cancer cell chemoresistance against 5-fluorouracil, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 10.1016/j.bbrc.2014.12.116, 457, 3, 353-357, 2015.02, The low chemoresistance of in vitro cancer cells inhibits the development of new anti-cancer drugs. Thus, development of a new in vitro culture system is required to increase the chemoresistance of in vitro cancer cells. Tumor cell-derived matrices have been reported to increase the chemoresistance of in vitro cancer cells. However, it remains unclear how tissue sources and the malignancy of cells used for the preparation of matrices affect the chemoresistance of tumor cell-derived matrices. Moreover, it remains unclear how the initial substrates used for the preparation of matrices affect the chemoresistance. In this study, we compared the effects of tissue sources and the malignancy of tumor cells, as well as the effect of the initial substrates on chemoresistance against 5-fluorouracil (5-FU). The chemoresistance of breast and colon cancer cells against 5-FU increased on matrices prepared with cells derived from the corresponding original tissues with higher malignancy. Moreover, the chemoresistance against 5-FU was altered on matrices prepared using different initial substrates that exhibited different characteristics of protein adsorption. Taken together, these results indicated that the appropriate selection of tissue sources, malignancy of tumor cells, and initial substrates used for matrix preparation is important for the preparation of tumor cell-derived matrices for chemoresistance assays. (C) 2015 Elsevier Inc. All rights reserved..
206. Masaru Tanaka, Kazuhiro Sato, Erika Kitakami, Shingo Kobayashi, Takashi Hoshiba, Kazuki Fukushima, Design of biocompatible and biodegradable polymers based on intermediate water concept, Polymer Journal, 10.1038/pj.2014.129, 47, 2, 114-121, 2015.01, Polymeric biomaterials have significant impact in the aged society. Biocompatible and biodegradable polymers have emerged during the past decades to promise extraordinary breakthroughs in a wide range of diagnostic and therapeutic medical devices. Understanding and controlling the interfacial interactions of the polymeric biomaterials with biological elements, such as water, ions, proteins, bacteria, fungai and cells, are essential toward their successful implementation in biomedical applications. Here we highlight the recent developments of biocompatible and biodegradable fusion polymeric biomaterials for medical devices and provide an overview of the recent progress of the design of the multi-functional biomedical polymers by controlling bio-interfacial water structure through precision polymer synthesis and supramolecular chemistry..
207. Shigeaki Morita, Masaru Tanaka, Effect of sodium chloride on hydration structures of PMEA and P(MPC- R -BMA), Langmuir, 10.1021/la502550d, 30, 35, 10698-10703, 2014.09, The hydration structures of two different types of biomaterials, i.e., poly(2-methoxyethyl acrylate) (PMEA) and a random copolymer of 2-methacryloyloxyethyl phosphorylcholine and n-butyl methacrylate (P(MPC-r-BMA)), were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy. The effects of the addition of sodium chloride to liquid water in contact with the surfaces of the polymer films were examined. The neutral polymer of PMEA was easily dehydrated by NaCl addition, whereas the zwitterionic polymer of P(MPC-r-BMA) was hardly dehydrated. More specifically, nonfreezing water having a strong interaction with the PMEA chain and freezing bound water having an intermediate interaction were hardly dehydrated by contacting with normal saline solution, whereas freezing water having a weak interaction with the PMEA chain was readily dehydrated. In contrast, freezing water in P(MPC-r-BMA) is exchanged for the saline solution contacting with the material surface without dehydration..
208. Shigeaki Morita, Masaru Tanaka, Effect of sodium chloride on hydration structures of PMEA and P(MPC- R -BMA), Langmuir, 10.1021/la502550d, 30, 35, 10698-10703, 2014.09, The hydration structures of two different types of biomaterials, i.e., poly(2-methoxyethyl acrylate) (PMEA) and a random copolymer of 2-methacryloyloxyethyl phosphorylcholine and n-butyl methacrylate (P(MPC-r-BMA)), were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy. The effects of the addition of sodium chloride to liquid water in contact with the surfaces of the polymer films were examined. The neutral polymer of PMEA was easily dehydrated by NaCl addition, whereas the zwitterionic polymer of P(MPC-r-BMA) was hardly dehydrated. More specifically, nonfreezing water having a strong interaction with the PMEA chain and freezing bound water having an intermediate interaction were hardly dehydrated by contacting with normal saline solution, whereas freezing water having a weak interaction with the PMEA chain was readily dehydrated. In contrast, freezing water in P(MPC-r-BMA) is exchanged for the saline solution contacting with the material surface without dehydration..
209. Shigeaki Morita, Masaru Tanaka, Effect of sodium chloride on hydration structures of PMEA and P(MPC- R -BMA), Langmuir, 10.1021/la502550d, 30, 35, 10698-10703, 2014.09, The hydration structures of two different types of biomaterials, i.e., poly(2-methoxyethyl acrylate) (PMEA) and a random copolymer of 2-methacryloyloxyethyl phosphorylcholine and n-butyl methacrylate (P(MPC-r-BMA)), were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy. The effects of the addition of sodium chloride to liquid water in contact with the surfaces of the polymer films were examined. The neutral polymer of PMEA was easily dehydrated by NaCl addition, whereas the zwitterionic polymer of P(MPC-r-BMA) was hardly dehydrated. More specifically, nonfreezing water having a strong interaction with the PMEA chain and freezing bound water having an intermediate interaction were hardly dehydrated by contacting with normal saline solution, whereas freezing water having a weak interaction with the PMEA chain was readily dehydrated. In contrast, freezing water in P(MPC-r-BMA) is exchanged for the saline solution contacting with the material surface without dehydration..
210. Shigeaki Morita, Masaru Tanaka, Effect of Sodium Chloride on Hydration Structures of PMEA and P(MPC-r-BMA), LANGMUIR, 10.1021/la502550d, 30, 35, 10698-10703, 2014.09, The hydration structures of two different types of biomaterials, i.e., poly(2-methoxyethyl acrylate) (PMEA) and a random copolymer of 2-methacryloyloxyethyl phosphorylcholine and n-butyl methacrylate (P(MPC-r-BMA)), were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy. The effects of the addition of sodium chloride to liquid water in contact with the surfaces of the polymer films were examined. The neutral polymer of PMEA was easily dehydrated by NaCl addition, whereas the zwitterionic polymer of P(MPC-r-BMA) was hardly dehydrated. More specifically, nonfreezing water having a strong interaction with the PMEA chain and freezing bound water having an intermediate interaction were hardly dehydrated by contacting with normal saline solution, whereas freezing water having a weak interaction with the PMEA chain was readily dehydrated. In contrast, freezing water in P(MPC-r-BMA) is exchanged for the saline solution contacting with the material surface without dehydration..
211. Facile and practical route to a versatile intermediate of substituted cyclic carbonates offering diverse smart biomaterials.
212. Takashi Hoshiba, Mayo Nikaido, Masaru Tanaka, Characterization of the attachment mechanisms of tissue-derived cell lines to blood-compatible polymers, Advanced Healthcare Materials, 10.1002/adhm.201300309, 3, 5, 775-784, 2014.06, Recent advances in biomedical engineering require the development of new types of blood-compatible polymers that also allow non-blood cell attachment for the isolation of stem cells and circulating tumor cells (CTCs) from blood and for the development of artificial organs for use under blood-contact conditions. Poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrafurfuryl acrylate) (PTHFA) were previously identified as blood-compatible polymers. Here, it is demonstrated that cancer cells can attach to the PMEA and PTHFA substrates, and the differences in the attachment mechanisms to the PMEA and PTHFA substrates between cancer cells and platelets are investigated. It is also found that the adsorption-induced deformation of fibrinogen, which is required for the attachment and activation of platelets, does not occur on the PMEA and PTHFA substrates. In contrast, fibronectin is deformed on the PMEA and PTHFA substrates. Therefore, it is concluded that cancer cells and not platelets can attach to the PMEA and PTHFA substrates based on this protein-deformation difference between these substrates. Moreover, it is observed that cancer cells attach to the PMEA substrate via both integrin-dependent and -independent mechanisms and attach to the PTHFA substrate only through an integrin-dependent mechanism. It is expected that PMEA and PTHFA will prove useful for blood-contact biomedical applications..
213. Takashi Hoshiba, Mayo Nikaido, Masaru Tanaka, Characterization of the attachment mechanisms of tissue-derived cell lines to blood-compatible polymers, Advanced Healthcare Materials, 10.1002/adhm.201300309, 3, 5, 775-784, 2014.05, Recent advances in biomedical engineering require the development of new types of blood-compatible polymers that also allow non-blood cell attachment for the isolation of stem cells and circulating tumor cells (CTCs) from blood and for the development of artificial organs for use under blood-contact conditions. Poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrafurfuryl acrylate) (PTHFA) were previously identified as blood-compatible polymers. Here, it is demonstrated that cancer cells can attach to the PMEA and PTHFA substrates, and the differences in the attachment mechanisms to the PMEA and PTHFA substrates between cancer cells and platelets are investigated. It is also found that the adsorption-induced deformation of fibrinogen, which is required for the attachment and activation of platelets, does not occur on the PMEA and PTHFA substrates. In contrast, fibronectin is deformed on the PMEA and PTHFA substrates. Therefore, it is concluded that cancer cells and not platelets can attach to the PMEA and PTHFA substrates based on this protein-deformation difference between these substrates. Moreover, it is observed that cancer cells attach to the PMEA substrate via both integrin-dependent and -independent mechanisms and attach to the PTHFA substrate only through an integrin-dependent mechanism. It is expected that PMEA and PTHFA will prove useful for blood-contact biomedical applications..
214. Takashi Hoshiba, Mayo Nikaido, Masaru Tanaka, Characterization of the Attachment Mechanisms of Tissue-Derived Cell Lines to Blood-Compatible Polymers, ADVANCED HEALTHCARE MATERIALS, 10.1002/adhm.201300309, 3, 5, 775-784, 2014.05, Recent advances in biomedical engineering require the development of new types of blood-compatible polymers that also allow non-blood cell attachment for the isolation of stem cells and circulating tumor cells (CTCs) from blood and for the development of artificial organs for use under blood-contact conditions. Poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrafurfuryl acrylate) (PTHFA) were previously identified as blood-compatible polymers. Here, it is demonstrated that cancer cells can attach to the PMEA and PTHFA substrates, and the differences in the attachment mechanisms to the PMEA and PTHFA substrates between cancer cells and platelets are investigated. It is also found that the adsorption-induced deformation of fibrinogen, which is required for the attachment and activation of platelets, does not occur on the PMEA and PTHFA substrates. In contrast, fibronectin is deformed on the PMEA and PTHFA substrates. Therefore, it is concluded that cancer cells and not platelets can attach to the PMEA and PTHFA substrates based on this protein-deformation difference between these substrates. Moreover, it is observed that cancer cells attach to the PMEA substrate via both integrin-dependent and -independent mechanisms and attach to the PTHFA substrate only through an integrin-dependent mechanism. It is expected that PMEA and PTHFA will prove useful for blood-contact biomedical applications..
215. Water structure of blood compatible polymers.
216. Hyunmi Choi, Masaru Tanaka, Takaaki Hiragun, Michihiro Hide, Koreaki Sugimoto, Non-tumor mast cells cultured in vitro on a honeycomb-like structured film proliferate with multinucleated formation, Nanomedicine: Nanotechnology, Biology, and Medicine, 10.1016/j.nano.2013.08.011, 10, 2, 313-319, 2014.02, Mast cells are released from bone marrow into the circulatory system as immature precursors and differentiate upon their arrival at diverse organs and tissues. Because mast cell functions can be altered in these tissues, we propose that mast cells are sensitive to their surrounding microenvironment. To examine the morphological responses of mast cells, we cultured a proliferative mouse non-tumor cell line of mast cells (NCL-2 cells) on a honeycomb-like structured polystyrene film (HCF) representing a microenvironmental scaffold. In this study, the NCL-2 cells cultured on the HCF proliferated without apoptosis. Furthermore, NCL-2 cells cultured on 3- and 5-μm HCFs exhibited multinuclear formation. These observations of different NCL-2 cell morphologies and proliferation rates on HCF scaffolds with different hole sizes suggest that mast cells undertake specific proliferative shapes depending on the surrounding microenviroment. Moreover, HCFs may lead to the regulation of mast cell differentiation. From the Clinical Editor: This team reports on the development of a honeycomb-like structured film to study mast cell differentiation of non-cancerous origin, demonstrating that different microenvironments provided by different honeycomb hole sizes determine the morphology of the differentiated cells..
217. Hyunmi Choi, Masaru Tanaka, Takaaki Hiragun, Michihiro Hide, Koreaki Sugimoto, Non-tumor mast cells cultured in vitro on a honeycomb-like structured film proliferate with multinucleated formation, Nanomedicine: Nanotechnology, Biology, and Medicine, 10.1016/j.nano.2013.08.011, 10, 2, 313-319, 2014.02, Mast cells are released from bone marrow into the circulatory system as immature precursors and differentiate upon their arrival at diverse organs and tissues. Because mast cell functions can be altered in these tissues, we propose that mast cells are sensitive to their surrounding microenvironment. To examine the morphological responses of mast cells, we cultured a proliferative mouse non-tumor cell line of mast cells (NCL-2 cells) on a honeycomb-like structured polystyrene film (HCF) representing a microenvironmental scaffold. In this study, the NCL-2 cells cultured on the HCF proliferated without apoptosis. Furthermore, NCL-2 cells cultured on 3- and 5-μm HCFs exhibited multinuclear formation. These observations of different NCL-2 cell morphologies and proliferation rates on HCF scaffolds with different hole sizes suggest that mast cells undertake specific proliferative shapes depending on the surrounding microenviroment. Moreover, HCFs may lead to the regulation of mast cell differentiation. From the Clinical Editor: This team reports on the development of a honeycomb-like structured film to study mast cell differentiation of non-cancerous origin, demonstrating that different microenvironments provided by different honeycomb hole sizes determine the morphology of the differentiated cells..
218. Hyunmi Choi, Masaru Tanaka, Takaaki Hiragun, Michihiro Hide, Koreaki Sugimoto, Non-tumor mast cells cultured in vitro on a honeycomb-like structured film proliferate with multinucleated formation, Nanomedicine: Nanotechnology, Biology, and Medicine, 10.1016/j.nano.2013.08.011, 10, 2, 313-319, 2014.02, Mast cells are released from bone marrow into the circulatory system as immature precursors and differentiate upon their arrival at diverse organs and tissues. Because mast cell functions can be altered in these tissues, we propose that mast cells are sensitive to their surrounding microenvironment. To examine the morphological responses of mast cells, we cultured a proliferative mouse non-tumor cell line of mast cells (NCL-2 cells) on a honeycomb-like structured polystyrene film (HCF) representing a microenvironmental scaffold. In this study, the NCL-2 cells cultured on the HCF proliferated without apoptosis. Furthermore, NCL-2 cells cultured on 3- and 5-μm HCFs exhibited multinuclear formation. These observations of different NCL-2 cell morphologies and proliferation rates on HCF scaffolds with different hole sizes suggest that mast cells undertake specific proliferative shapes depending on the surrounding microenviroment. Moreover, HCFs may lead to the regulation of mast cell differentiation. From the Clinical Editor: This team reports on the development of a honeycomb-like structured film to study mast cell differentiation of non-cancerous origin, demonstrating that different microenvironments provided by different honeycomb hole sizes determine the morphology of the differentiated cells..
219. Erika Kitakami, Makiko Aoki, Chikako Sato, Hiroshi Ishihata, Masaru Tanaka, Adhesion and proliferation of human periodontal ligament cells on poly(2-methoxyethyl acrylate), BioMed Research International, 10.1155/2014/102648, 2014, 2014.01, Human periodontal ligament (PDL) cells obtained from extracted teeth are a potential cell source for tissue engineering. We previously reported that poly(2-methoxyethyl acrylate) (PMEA) is highly biocompatible with human blood cells. In this study, we investigated the adhesion, morphology, and proliferation of PDL cells on PMEA and other types of polymers to design an appropriate scaffold for tissue engineering. PDL cells adhered and proliferated on all investigated polymer surfaces except for poly(2-hydroxyethyl methacrylate) and poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(n-butyl methacrylate)]. The initial adhesion of the PDL cells on PMEA was comparable with that on polyethylene terephthalate (PET). In addition, the PDL cells on PMEA spread well and exhibited proliferation behavior similar to that observed on PET. In contrast, platelets hardly adhered to PMEA. PMEA is therefore expected to be an excellent scaffold for tissue engineering and for culturing tissue-derived cells in a blood-rich environment..
220. Masaru Tanaka, Biocompatible 2D and 3D polymeric scaffolds for medical devices, Horizons in Clinical Nanomedicine, 10.4032/9789814411578, 229-253, 2014.01.
221. Joshua O. Eniwumide, Masaru Tanaka, Nobuhiro Nagai, Yuka Morita, Joost De Bruijn, Sadaaki Yamamoto, Shin Onodera, Eiji Kondo, Kazunori Yasuda, Masatsugu Shimomura, The morphology and functions of articular chondrocytes on a honeycomb-patterned surface, BioMed Research International, 10.1155/2014/710354, 2014, 2014.01, The present study investigated the potential of a novel micropatterned substrate for neocartilage formation. Articular chondrocytes were cultured on poly(ε-caprolactone) materials whose surfaces were either flat or honeycomb-patterned. The latter was prepared using a novel self-organization technique, while the former, was prepared by spin-coating. The chondrocytes attached and proliferated on both surfaces. On the honeycomb films, chondrocytes were found at the top surface and encased within the 10 μm pores. Meanwhile, chondrocytes on the spin-coated surface flattened out. Accumulation of DNA and keratin sulphate was comparatively higher on the honeycomb films within the first 7 days. At their respective peaks, DNA concentration increased on the honeycomb and flat surfaces by approximately 210% and 400% of their day 1 values, respectively. However, cultures on the flat surface took longer to peak. Extracellular Matrix (ECM) concentrations peaked at 900% and 320% increases for the honeycomb and flat cultures. Type II collagen was upregulated on the honeycomb and flat surfaces by as much as 28% and 25% of their day 1 values, while aggrecan was downregulated with time, by 3.4% and 7.4%. These initial results demonstrate the potential usefulness of honeycomb-based scaffolds during early cultures neocartilage and soft tissue engineering..
222. Erika Kitakami, Makiko Aoki, Chikako Sato, Hiroshi Ishihata, Masaru Tanaka, Adhesion and proliferation of human periodontal ligament cells on poly(2-methoxyethyl acrylate), BioMed Research International, 10.1155/2014/102648, 2014, 2014.01, Human periodontal ligament (PDL) cells obtained from extracted teeth are a potential cell source for tissue engineering. We previously reported that poly(2-methoxyethyl acrylate) (PMEA) is highly biocompatible with human blood cells. In this study, we investigated the adhesion, morphology, and proliferation of PDL cells on PMEA and other types of polymers to design an appropriate scaffold for tissue engineering. PDL cells adhered and proliferated on all investigated polymer surfaces except for poly(2-hydroxyethyl methacrylate) and poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(n-butyl methacrylate)]. The initial adhesion of the PDL cells on PMEA was comparable with that on polyethylene terephthalate (PET). In addition, the PDL cells on PMEA spread well and exhibited proliferation behavior similar to that observed on PET. In contrast, platelets hardly adhered to PMEA. PMEA is therefore expected to be an excellent scaffold for tissue engineering and for culturing tissue-derived cells in a blood-rich environment..
223. Masaru Tanaka, Biocompatible 2D and 3D polymeric scaffolds for medical devices, Horizons in Clinical Nanomedicine, 10.4032/9789814411578, 229-253, 2014.01.
224. Takashi Hoshiba, Mayo Nikaido, Masaru Tanaka, Characterization of the attachment mechanisms of tissue-derived cell lines to blood-compatible polymers, Advanced Healthcare Materials, 10.1002/adhm.201300309, 3, 5, 775-784, 2014.01, Recent advances in biomedical engineering require the development of new types of blood-compatible polymers that also allow non-blood cell attachment for the isolation of stem cells and circulating tumor cells (CTCs) from blood and for the development of artificial organs for use under blood-contact conditions. Poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrafurfuryl acrylate) (PTHFA) were previously identified as blood-compatible polymers. Here, it is demonstrated that cancer cells can attach to the PMEA and PTHFA substrates, and the differences in the attachment mechanisms to the PMEA and PTHFA substrates between cancer cells and platelets are investigated. It is also found that the adsorption-induced deformation of fibrinogen, which is required for the attachment and activation of platelets, does not occur on the PMEA and PTHFA substrates. In contrast, fibronectin is deformed on the PMEA and PTHFA substrates. Therefore, it is concluded that cancer cells and not platelets can attach to the PMEA and PTHFA substrates based on this protein-deformation difference between these substrates. Moreover, it is observed that cancer cells attach to the PMEA substrate via both integrin-dependent and -independent mechanisms and attach to the PTHFA substrate only through an integrin-dependent mechanism. It is expected that PMEA and PTHFA will prove useful for blood-contact biomedical applications..
225. Joshua O. Eniwumide, Masaru Tanaka, Nobuhiro Nagai, Yuka Morita, Joost De Bruijn, Sadaaki Yamamoto, Shin Onodera, Eiji Kondo, Kazunori Yasuda, Masatsugu Shimomura, The morphology and functions of articular chondrocytes on a honeycomb-patterned surface, BioMed Research International, 10.1155/2014/710354, 2014, 2014.01, The present study investigated the potential of a novel micropatterned substrate for neocartilage formation. Articular chondrocytes were cultured on poly(ε-caprolactone) materials whose surfaces were either flat or honeycomb-patterned. The latter was prepared using a novel self-organization technique, while the former, was prepared by spin-coating. The chondrocytes attached and proliferated on both surfaces. On the honeycomb films, chondrocytes were found at the top surface and encased within the 10 μm pores. Meanwhile, chondrocytes on the spin-coated surface flattened out. Accumulation of DNA and keratin sulphate was comparatively higher on the honeycomb films within the first 7 days. At their respective peaks, DNA concentration increased on the honeycomb and flat surfaces by approximately 210% and 400% of their day 1 values, respectively. However, cultures on the flat surface took longer to peak. Extracellular Matrix (ECM) concentrations peaked at 900% and 320% increases for the honeycomb and flat cultures. Type II collagen was upregulated on the honeycomb and flat surfaces by as much as 28% and 25% of their day 1 values, while aggrecan was downregulated with time, by 3.4% and 7.4%. These initial results demonstrate the potential usefulness of honeycomb-based scaffolds during early cultures neocartilage and soft tissue engineering..
226. Erika Kitakami, Makiko Aoki, Chikako Sato, Hiroshi Ishihata, Masaru Tanaka, Adhesion and proliferation of human periodontal ligament cells on poly(2-methoxyethyl acrylate), BioMed Research International, 10.1155/2014/102648, 2014, 2014.01, Human periodontal ligament (PDL) cells obtained from extracted teeth are a potential cell source for tissue engineering. We previously reported that poly(2-methoxyethyl acrylate) (PMEA) is highly biocompatible with human blood cells. In this study, we investigated the adhesion, morphology, and proliferation of PDL cells on PMEA and other types of polymers to design an appropriate scaffold for tissue engineering. PDL cells adhered and proliferated on all investigated polymer surfaces except for poly(2-hydroxyethyl methacrylate) and poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(n-butyl methacrylate)]. The initial adhesion of the PDL cells on PMEA was comparable with that on polyethylene terephthalate (PET). In addition, the PDL cells on PMEA spread well and exhibited proliferation behavior similar to that observed on PET. In contrast, platelets hardly adhered to PMEA. PMEA is therefore expected to be an excellent scaffold for tissue engineering and for culturing tissue-derived cells in a blood-rich environment..
227. Masaru Tanaka, Biocompatible 2D and 3D polymeric scaffolds for medical devices, Horizons in Clinical Nanomedicine, 10.4032/9789814411578, 229-253, 2014.01.
228. Masaru Tanaka, Biocompatible 2D and 3D polymeric scaffolds for medical devices, Horizons in Clinical Nanomedicine, 10.4032/9789814411578, 229-253, 2014.01.
229. Characterization of cell attachment mechanism of tumor cells on blood compatible polymer, PMEA.
230. Masaru Tanaka, Honeycomb-like structured film regulates mediator release from non-tumor mast cells, European Journal of Inflammation, 12, 515, 2014.
231. Masaru Tanaka, Non-tumor mast cells cultured in vitro on a honeycomb-like structured film prpliferate with multinucleateaed formation, Nanomedicine: Nanotechnology, Biology, and Medicine, 10, 313, 2014.
232. Masaru Tanaka, Honeycomb-like structured film regulates mediator release from non-tumor mast cells, European Journal of Inflammation, 12, 515, 2014.
233. Masaru Tanaka, Non-tumor mast cells cultured in vitro on a honeycomb-like structured film prpliferate with multinucleateaed formation, Nanomedicine: Nanotechnology, Biology, and Medicine, 10, 313, 2014.
234. Masaru Tanaka, Honeycomb-like structured film regulates mediator release from non-tumor mast cells, European Journal of Inflammation, 12, 515, 2014.
235. Masaru Tanaka, Non-tumor mast cells cultured in vitro on a honeycomb-like structured film prpliferate with multinucleateaed formation, Nanomedicine: Nanotechnology, Biology, and Medicine, 10, 313, 2014.
236. Joshua O. Eniwumide, Masaru Tanaka, Nobuhiro Nagai, Yuka Morita, Joost De Bruijn, Sadaaki Yamamoto, Shin Onodera, Eiji Kondo, Kazunori Yasuda, Masatsugu Shimomura, The morphology and functions of articular chondrocytes on a honeycomb-patterned surface, BioMed Research International, 10.1155/2014/710354, 2014, 2014, The present study investigated the potential of a novel micropatterned substrate for neocartilage formation. Articular chondrocytes were cultured on poly(ε-caprolactone) materials whose surfaces were either flat or honeycomb-patterned. The latter was prepared using a novel self-organization technique, while the former, was prepared by spin-coating. The chondrocytes attached and proliferated on both surfaces. On the honeycomb films, chondrocytes were found at the top surface and encased within the 10 μm pores. Meanwhile, chondrocytes on the spin-coated surface flattened out. Accumulation of DNA and keratin sulphate was comparatively higher on the honeycomb films within the first 7 days. At their respective peaks, DNA concentration increased on the honeycomb and flat surfaces by approximately 210% and 400% of their day 1 values, respectively. However, cultures on the flat surface took longer to peak. Extracellular Matrix (ECM) concentrations peaked at 900% and 320% increases for the honeycomb and flat cultures. Type II collagen was upregulated on the honeycomb and flat surfaces by as much as 28% and 25% of their day 1 values, while aggrecan was downregulated with time, by 3.4% and 7.4%. These initial results demonstrate the potential usefulness of honeycomb-based scaffolds during early cultures neocartilage and soft tissue engineering..
237. Tomohiro Hayashi, Yusaku Tanaka, Yuki Koide, Masaru Tanaka, Masahiko Hara, Erratum
Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold: Protein adsorption, platelet adhesion, and surface forces (Physical Chemistry Chemical Physics (2012) 14 (10196-10206) DOI: 10.1039/C2CP41236E), Physical Chemistry Chemical Physics, 10.1039/c3cp90155f, 15, 48, 2013.12.
238. Tomohiro Hayashi, Yusaku Tanaka, Yuki Koide, Masaru Tanaka, Masahiko Hara, Erratum
Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold: Protein adsorption, platelet adhesion, and surface forces (Physical Chemistry Chemical Physics (2012) 14 (10196-10206) DOI: 10.1039/C2CP41236E), Physical Chemistry Chemical Physics, 10.1039/c3cp90155f, 15, 48, 2013.12.
239. Tomohiro Hayashi, Yusaku Tanaka, Yuki Koide, Masaru Tanaka, Masahiko Hara, Erratum
Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold: Protein adsorption, platelet adhesion, and surface forces (Physical Chemistry Chemical Physics (2012) 14 (10196-10206) DOI: 10.1039/C2CP41236E), Physical Chemistry Chemical Physics, 10.1039/c3cp90155f, 15, 48, 2013.12.
240. Takashi Hoshiba, Masaru Tanaka, Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2013.08.038, 439, 2, 291-296, 2013.09, Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared "staged tumorigenesis-mimicking matrices" which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression..
241. Mark A. Birch, Masaru Tanaka, George Kirmizidis, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, Tissue Engineering - Part A., 10.1089/ten.tea.2012.0729, 19, 17-18, 2087-2096, 2013.09, Substrate topography influences cell adhesion, proliferation, and differentiation. In this study, poly (ε-caprolactone) (PCL) films with a well-defined honeycomb structure of porosity 3-4, 5-6, 10-11, or 15-16 μm were contrasted with flat surfaces for their ability to support primary rat osteoblast adhesion and mineralized extracellular matrix deposition in vitro. Immunofluorescent visualization of vinculin and rhodamine phalloidin binding of actin were used to investigate cell adhesion and morphology. Localization of the alkaline phosphatase activity and Alizarin Red staining were performed to assess the osteoblast activity and deposition of a mineralized matrix. Scanning electron microscopy together with energy-dispersive X-ray spectroscopy was used to provide morphological analysis of cell-film interactions, the deposited matrix, and elemental analysis of the mineralized structures. After 24 h of culture, there were no differences in cell numbers on porous or flat PCL surfaces, but there were changes in cell morphology. Osteoblasts on honeycomb films had a smaller surface area and were less circular than cells on flat PCL. Analysis of cells cultured for 35 days under osteogenic conditions revealed that osteoblasts on all substrates acquired alkaline phosphatase activity, but levels of mineralized matrix were increased on films with 3-4-μm pore sizes. The bone-like matrix with a Ca:P ratio of 1.69±0.08 could be identified in larger areas often aligning with substrate topography. In addition, smaller spherical deposits (0.5-1 μm in diameter) with a Ca:P ratio of 1.3±0.08 were observed at the surface and particularly within the pores of the PCL film. Localization of vinculin showed significant decreases in the number of focal adhesion structures per unit cell area on 5-6, 10-11, and 15-16-μm surfaces compared to flat PCL, while focal complexes with a smaller area (0-2 μm2) were more abundant on 3-4 and 5-6-μm surfaces. Observation of cell interaction with these surfaces identified cytoplasmic protrusions that extended into and sealed the pores of these PCL films creating an extracellular space in which, the conditions could influence the deposition and formation of the mineralized matrix..
242. Takashi Hoshiba, Masaru Tanaka, Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2013.08.038, 439, 2, 291-296, 2013.09, Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared "staged tumorigenesis-mimicking matrices" which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression..
243. Mark A. Birch, Masaru Tanaka, George Kirmizidis, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, Tissue Engineering - Part A, 10.1089/ten.tea.2012.0729, 19, 17-18, 2087-2096, 2013.09, Substrate topography influences cell adhesion, proliferation, and differentiation. In this study, poly (ε-caprolactone) (PCL) films with a well-defined honeycomb structure of porosity 3-4, 5-6, 10-11, or 15-16 μm were contrasted with flat surfaces for their ability to support primary rat osteoblast adhesion and mineralized extracellular matrix deposition in vitro. Immunofluorescent visualization of vinculin and rhodamine phalloidin binding of actin were used to investigate cell adhesion and morphology. Localization of the alkaline phosphatase activity and Alizarin Red staining were performed to assess the osteoblast activity and deposition of a mineralized matrix. Scanning electron microscopy together with energy-dispersive X-ray spectroscopy was used to provide morphological analysis of cell-film interactions, the deposited matrix, and elemental analysis of the mineralized structures. After 24 h of culture, there were no differences in cell numbers on porous or flat PCL surfaces, but there were changes in cell morphology. Osteoblasts on honeycomb films had a smaller surface area and were less circular than cells on flat PCL. Analysis of cells cultured for 35 days under osteogenic conditions revealed that osteoblasts on all substrates acquired alkaline phosphatase activity, but levels of mineralized matrix were increased on films with 3-4-μm pore sizes. The bone-like matrix with a Ca:P ratio of 1.69±0.08 could be identified in larger areas often aligning with substrate topography. In addition, smaller spherical deposits (0.5-1 μm in diameter) with a Ca:P ratio of 1.3±0.08 were observed at the surface and particularly within the pores of the PCL film. Localization of vinculin showed significant decreases in the number of focal adhesion structures per unit cell area on 5-6, 10-11, and 15-16-μm surfaces compared to flat PCL, while focal complexes with a smaller area (0-2 μm2) were more abundant on 3-4 and 5-6-μm surfaces. Observation of cell interaction with these surfaces identified cytoplasmic protrusions that extended into and sealed the pores of these PCL films creating an extracellular space in which, the conditions could influence the deposition and formation of the mineralized matrix..
244. Takashi Hoshiba, Masaru Tanaka, Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2013.08.038, 439, 2, 291-296, 2013.09, Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared "staged tumorigenesis-mimicking matrices" which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression..
245. Mark A. Birch, Masaru Tanaka, George Kirmizidis, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, Tissue Engineering - Part A, 10.1089/ten.tea.2012.0729, 19, 17-18, 2087-2096, 2013.09, Substrate topography influences cell adhesion, proliferation, and differentiation. In this study, poly (ε-caprolactone) (PCL) films with a well-defined honeycomb structure of porosity 3-4, 5-6, 10-11, or 15-16 μm were contrasted with flat surfaces for their ability to support primary rat osteoblast adhesion and mineralized extracellular matrix deposition in vitro. Immunofluorescent visualization of vinculin and rhodamine phalloidin binding of actin were used to investigate cell adhesion and morphology. Localization of the alkaline phosphatase activity and Alizarin Red staining were performed to assess the osteoblast activity and deposition of a mineralized matrix. Scanning electron microscopy together with energy-dispersive X-ray spectroscopy was used to provide morphological analysis of cell-film interactions, the deposited matrix, and elemental analysis of the mineralized structures. After 24 h of culture, there were no differences in cell numbers on porous or flat PCL surfaces, but there were changes in cell morphology. Osteoblasts on honeycomb films had a smaller surface area and were less circular than cells on flat PCL. Analysis of cells cultured for 35 days under osteogenic conditions revealed that osteoblasts on all substrates acquired alkaline phosphatase activity, but levels of mineralized matrix were increased on films with 3-4-μm pore sizes. The bone-like matrix with a Ca:P ratio of 1.69±0.08 could be identified in larger areas often aligning with substrate topography. In addition, smaller spherical deposits (0.5-1 μm in diameter) with a Ca:P ratio of 1.3±0.08 were observed at the surface and particularly within the pores of the PCL film. Localization of vinculin showed significant decreases in the number of focal adhesion structures per unit cell area on 5-6, 10-11, and 15-16-μm surfaces compared to flat PCL, while focal complexes with a smaller area (0-2 μm2) were more abundant on 3-4 and 5-6-μm surfaces. Observation of cell interaction with these surfaces identified cytoplasmic protrusions that extended into and sealed the pores of these PCL films creating an extracellular space in which, the conditions could influence the deposition and formation of the mineralized matrix..
246. Antithrombotic biodegradable polycarbonates for regenerative medicines.
247. Takashi Hoshiba, Masaru Tanaka, Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 10.1016/j.bbrc.2013.08.038, 439, 2, 291-296, 2013.09, Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared "staged tumorigenesis-mimicking matrices" which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression. (C) 2013 Elsevier Inc. All rights reserved..
248. Mark A. Birch, Masaru Tanaka, George Kirmizidis, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, Tissue Engineering - Part A, 10.1089/ten.tea.2012.0729, 19, 17-18, 2087-2096, 2013.09, Substrate topography influences cell adhesion, proliferation, and differentiation. In this study, poly (ε-caprolactone) (PCL) films with a well-defined honeycomb structure of porosity 3-4, 5-6, 10-11, or 15-16 μm were contrasted with flat surfaces for their ability to support primary rat osteoblast adhesion and mineralized extracellular matrix deposition in vitro. Immunofluorescent visualization of vinculin and rhodamine phalloidin binding of actin were used to investigate cell adhesion and morphology. Localization of the alkaline phosphatase activity and Alizarin Red staining were performed to assess the osteoblast activity and deposition of a mineralized matrix. Scanning electron microscopy together with energy-dispersive X-ray spectroscopy was used to provide morphological analysis of cell-film interactions, the deposited matrix, and elemental analysis of the mineralized structures. After 24 h of culture, there were no differences in cell numbers on porous or flat PCL surfaces, but there were changes in cell morphology. Osteoblasts on honeycomb films had a smaller surface area and were less circular than cells on flat PCL. Analysis of cells cultured for 35 days under osteogenic conditions revealed that osteoblasts on all substrates acquired alkaline phosphatase activity, but levels of mineralized matrix were increased on films with 3-4-μm pore sizes. The bone-like matrix with a Ca:P ratio of 1.69±0.08 could be identified in larger areas often aligning with substrate topography. In addition, smaller spherical deposits (0.5-1 μm in diameter) with a Ca:P ratio of 1.3±0.08 were observed at the surface and particularly within the pores of the PCL film. Localization of vinculin showed significant decreases in the number of focal adhesion structures per unit cell area on 5-6, 10-11, and 15-16-μm surfaces compared to flat PCL, while focal complexes with a smaller area (0-2 μm2) were more abundant on 3-4 and 5-6-μm surfaces. Observation of cell interaction with these surfaces identified cytoplasmic protrusions that extended into and sealed the pores of these PCL films creating an extracellular space in which, the conditions could influence the deposition and formation of the mineralized matrix. © Mary Ann Liebert, Inc..
249. Masaru Tanaka, Tomohiro Hayashi, Shigeaki Morita, The roles of water molecules at the biointerface of medical polymers, Polymer Journal, 10.1038/pj.2012.229, 45, 7, 701-710, 2013.07, A number of materials have been proposed for use as biomaterials, including hydrophilic, phase-separated and zwitterionic polymers. The mechanisms responsible for the bio/blood compatibility (bioinertness) of these polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the biological response to contact with biomaterials. We have proposed the 'intermediate water' concept, in which water clearly exhibits defined peaks for cold crystallization in the differential scanning calorimetry chart and presents a strong peak at 3400 cm-1 in a time-resolved infrared spectrum. We found a localized hydration structure consisting of three hydrated waters in poly(2-methoxyethyl acrylate). We hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or non-freezing water on the polymer surface has an important role in the bio/blood compatibility of polymers. We will provide an overview of the recent experimental progress and a theoretical description of the bio/blood compatibility mechanisms as determined by thermal, spectroscopic and surface force measurements..
250. Masaru Tanaka, Tomohiro Hayashi, Shigeaki Morita, The roles of water molecules at the biointerface of medical polymers, Polymer Journal, 10.1038/pj.2012.229, 45, 7, 701-710, 2013.07, A number of materials have been proposed for use as biomaterials, including hydrophilic, phase-separated and zwitterionic polymers. The mechanisms responsible for the bio/blood compatibility (bioinertness) of these polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the biological response to contact with biomaterials. We have proposed the 'intermediate water' concept, in which water clearly exhibits defined peaks for cold crystallization in the differential scanning calorimetry chart and presents a strong peak at 3400 cm
-1
in a time-resolved infrared spectrum. We found a localized hydration structure consisting of three hydrated waters in poly(2-methoxyethyl acrylate). We hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or non-freezing water on the polymer surface has an important role in the bio/blood compatibility of polymers. We will provide an overview of the recent experimental progress and a theoretical description of the bio/blood compatibility mechanisms as determined by thermal, spectroscopic and surface force measurements..
251. Masaru Tanaka, Tomohiro Hayashi, Shigeaki Morita, The roles of water molecules at the biointerface of medical polymers, Polymer Journal, 10.1038/pj.2012.229, 45, 7, 701-710, 2013.07, A number of materials have been proposed for use as biomaterials, including hydrophilic, phase-separated and zwitterionic polymers. The mechanisms responsible for the bio/blood compatibility (bioinertness) of these polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the biological response to contact with biomaterials. We have proposed the 'intermediate water' concept, in which water clearly exhibits defined peaks for cold crystallization in the differential scanning calorimetry chart and presents a strong peak at 3400 cm-1 in a time-resolved infrared spectrum. We found a localized hydration structure consisting of three hydrated waters in poly(2-methoxyethyl acrylate). We hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or non-freezing water on the polymer surface has an important role in the bio/blood compatibility of polymers. We will provide an overview of the recent experimental progress and a theoretical description of the bio/blood compatibility mechanisms as determined by thermal, spectroscopic and surface force measurements..
252. Masaru Tanaka, Tomohiro Hayashi, Shigeaki Morita, The roles of water molecules at the biointerface of medical polymers, POLYMER JOURNAL, 10.1038/pj.2012.229, 45, 7, 701-710, 2013.07, A number of materials have been proposed for use as biomaterials, including hydrophilic, phase-separated and zwitterionic polymers. The mechanisms responsible for the bio/blood compatibility (bioinertness) of these polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to understand these mechanisms. Water interactions have been recognized as fundamental for the biological response to contact with biomaterials. We have proposed the 'intermediate water' concept, in which water clearly exhibits defined peaks for cold crystallization in the differential scanning calorimetry chart and presents a strong peak at 3400 cm(-1) in a time-resolved infrared spectrum. We found a localized hydration structure consisting of three hydrated waters in poly(2-methoxyethyl acrylate). We hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or non-freezing water on the polymer surface has an important role in the bio/blood compatibility of polymers. We will provide an overview of the recent experimental progress and a theoretical description of the bio/blood compatibility mechanisms as determined by thermal, spectroscopic and surface force measurements..
253. Tomohiro Hayashi, Yusaku Tanaka, Yuki Koide, Masaru Tanaka, Masahiko Hara, Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold
Protein adsorption, platelet adhesion, and surface forces, Physical Chemistry Chemical Physics, 10.1039/c2cp41236e, 14, 29, 10196-10206, 2012.08, The mechanism underlying the bioinertness of the self-assembled monolayers of oligo(ethylene glycol)-terminated alkanethiol (OEG-SAM) was investigated with protein adsorption experiments, platelet adhesion tests, and surface force measurements with an atomic force microscope (AFM). In this work, we performed systematic analysis with SAMs having various terminal groups (-OEG, -OH, -COOH, -NH2, and -CH3). The results of the protein adsorption experiment by the quartz crystal microbalance (QCM) method suggested that having one EG unit and the neutrality of total charges of the terminal groups are essential for protein-resistance. In particular, QCM with energy dissipation analyses indicated that proteins absorb onto the OEG-SAM via a very weak interaction compared with other SAMs. Contrary to the protein resistance, at least three EG units as well as the charge neutrality of the SAM are found to be required for anti-platelet adhesion. When the identical SAMs were formed on both AFM probe and substrate, our force measurements revealed that only the OEG-SAMs possessing more than two EG units showed strong repulsion in the range of 4 to 6 nm. In addition, we found that the SAMs with other terminal groups did not exhibit such repulsion. The repulsion between OEG-SAMs was always observed independent of solution conditions [NaCl concentration (between 0 and 1 M) and pH (between 3 and 11)] and was not observed in solution mixed with ethanol, which disrupts the three-dimensional network of the water molecules. We therefore concluded that the repulsion originated from structured interfacial water molecules. Considering the correlation between the above results, we propose that the layer of the structured interfacial water with a thickness of 2 to 3 nm (half of the range of the repulsion observed in the surface force measurements) plays an important role in deterring proteins and platelets from adsorption or adhesion..
254. Tomohiro Hayashi, Yusaku Tanaka, Yuki Koide, Masaru Tanaka, Masahiko Hara, Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold
Protein adsorption, platelet adhesion, and surface forces, Physical Chemistry Chemical Physics, 10.1039/c2cp41236e, 14, 29, 10196-10206, 2012.08, The mechanism underlying the bioinertness of the self-assembled monolayers of oligo(ethylene glycol)-terminated alkanethiol (OEG-SAM) was investigated with protein adsorption experiments, platelet adhesion tests, and surface force measurements with an atomic force microscope (AFM). In this work, we performed systematic analysis with SAMs having various terminal groups (-OEG, -OH, -COOH, -NH2, and -CH3). The results of the protein adsorption experiment by the quartz crystal microbalance (QCM) method suggested that having one EG unit and the neutrality of total charges of the terminal groups are essential for protein-resistance. In particular, QCM with energy dissipation analyses indicated that proteins absorb onto the OEG-SAM via a very weak interaction compared with other SAMs. Contrary to the protein resistance, at least three EG units as well as the charge neutrality of the SAM are found to be required for anti-platelet adhesion. When the identical SAMs were formed on both AFM probe and substrate, our force measurements revealed that only the OEG-SAMs possessing more than two EG units showed strong repulsion in the range of 4 to 6 nm. In addition, we found that the SAMs with other terminal groups did not exhibit such repulsion. The repulsion between OEG-SAMs was always observed independent of solution conditions [NaCl concentration (between 0 and 1 M) and pH (between 3 and 11)] and was not observed in solution mixed with ethanol, which disrupts the three-dimensional network of the water molecules. We therefore concluded that the repulsion originated from structured interfacial water molecules. Considering the correlation between the above results, we propose that the layer of the structured interfacial water with a thickness of 2 to 3 nm (half of the range of the repulsion observed in the surface force measurements) plays an important role in deterring proteins and platelets from adsorption or adhesion..
255. Tomohiro Hayashi, Yusaku Tanaka, Yuki Koide, Masaru Tanaka, Masahiko Hara, Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold
Protein adsorption, platelet adhesion, and surface forces, Physical Chemistry Chemical Physics, 10.1039/c2cp41236e, 14, 29, 10196-10206, 2012.08, The mechanism underlying the bioinertness of the self-assembled monolayers of oligo(ethylene glycol)-terminated alkanethiol (OEG-SAM) was investigated with protein adsorption experiments, platelet adhesion tests, and surface force measurements with an atomic force microscope (AFM). In this work, we performed systematic analysis with SAMs having various terminal groups (-OEG, -OH, -COOH, -NH2, and -CH3). The results of the protein adsorption experiment by the quartz crystal microbalance (QCM) method suggested that having one EG unit and the neutrality of total charges of the terminal groups are essential for protein-resistance. In particular, QCM with energy dissipation analyses indicated that proteins absorb onto the OEG-SAM via a very weak interaction compared with other SAMs. Contrary to the protein resistance, at least three EG units as well as the charge neutrality of the SAM are found to be required for anti-platelet adhesion. When the identical SAMs were formed on both AFM probe and substrate, our force measurements revealed that only the OEG-SAMs possessing more than two EG units showed strong repulsion in the range of 4 to 6 nm. In addition, we found that the SAMs with other terminal groups did not exhibit such repulsion. The repulsion between OEG-SAMs was always observed independent of solution conditions [NaCl concentration (between 0 and 1 M) and pH (between 3 and 11)] and was not observed in solution mixed with ethanol, which disrupts the three-dimensional network of the water molecules. We therefore concluded that the repulsion originated from structured interfacial water molecules. Considering the correlation between the above results, we propose that the layer of the structured interfacial water with a thickness of 2 to 3 nm (half of the range of the repulsion observed in the surface force measurements) plays an important role in deterring proteins and platelets from adsorption or adhesion..
256. Tatsuko Hatakeyama, Masaru Tanaka, Akira Kishi, Hyoe Hatakeyama, Comparison of measurement techniques for the identification of bound water restrained by polymers, Thermochimica Acta, 10.1016/j.tca.2011.01.027, 532, 159-163, 2012.03, We attempted to compare the measurement methods concerning characterization of bound water restrained by hydrophilic polymers having biocompatibility, since the structural change of water on the surface of bio-membranes has attracted considerable attentions. In particular, calorimetry that has been used for quantitative analysis of bound water in bio-membranes has been criticised in terms of the results obtained by nuclear magnetic resonance spectrometry, infrared/Raman spectrometry, X-ray analysis, and neutron scattering measurements. Based on the identical definition of bound water, and by using biocompatible polymers, the present status of calorimetry is investigated in order to identify and quantify the bound water restrained by bio-membranes..
257. Tatsuko Hatakeyama, Masaru Tanaka, Akira Kishi, Hyoe Hatakeyama, Comparison of measurement techniques for the identification of bound water restrained by polymers, Thermochimica Acta, 10.1016/j.tca.2011.01.027, 532, 159-163, 2012.03, We attempted to compare the measurement methods concerning characterization of bound water restrained by hydrophilic polymers having biocompatibility, since the structural change of water on the surface of bio-membranes has attracted considerable attentions. In particular, calorimetry that has been used for quantitative analysis of bound water in bio-membranes has been criticised in terms of the results obtained by nuclear magnetic resonance spectrometry, infrared/Raman spectrometry, X-ray analysis, and neutron scattering measurements. Based on the identical definition of bound water, and by using biocompatible polymers, the present status of calorimetry is investigated in order to identify and quantify the bound water restrained by bio-membranes..
258. Tatsuko Hatakeyama, Masaru Tanaka, Akira Kishi, Hyoe Hatakeyama, Comparison of measurement techniques for the identification of bound water restrained by polymers, Thermochimica Acta, 10.1016/j.tca.2011.01.027, 532, 159-163, 2012.03, We attempted to compare the measurement methods concerning characterization of bound water restrained by hydrophilic polymers having biocompatibility, since the structural change of water on the surface of bio-membranes has attracted considerable attentions. In particular, calorimetry that has been used for quantitative analysis of bound water in bio-membranes has been criticised in terms of the results obtained by nuclear magnetic resonance spectrometry, infrared/Raman spectrometry, X-ray analysis, and neutron scattering measurements. Based on the identical definition of bound water, and by using biocompatible polymers, the present status of calorimetry is investigated in order to identify and quantify the bound water restrained by bio-membranes..
259. Tatsuko Hatakeyama, Masaru Tanaka, Akira Kishi, Hyoe Hatakeyama, Comparison of measurement techniques for the identification of bound water restrained by polymers, THERMOCHIMICA ACTA, 10.1016/j.tca.2011.01.027, 532, 159-163, 2012.03, We attempted to compare the measurement methods concerning characterization of bound water restrained by hydrophilic polymers having biocompatibility, since the structural change of water on the surface of bio-membranes has attracted considerable attentions. In particular, calorimetry that has been used for quantitative analysis of bound water in bio-membranes has been criticised in terms of the results obtained by nuclear magnetic resonance spectrometry, infrared/Raman spectrometry. X-ray analysis, and neutron scattering measurements. Based on the identical definition of bound water, and by using biocompatible polymers, the present status of calorimetry is investigated in order to identify and quantify the bound water restrained by bio-membranes. (C) 2011 Elsevier B.V. All rights reserved..
260. Irakli Javakhishvili, Masaru Tanaka, Keiko Ogura, Katja Jankova, Søren Hvilsted, Synthesis of graft copolymers based on poly(2-methoxyethyl acrylate) and investigation of the associated water structure, Macromolecular Rapid Communications, 10.1002/marc.201100698, 33, 4, 319-325, 2012.02, Graft copolymers composed of poly(2-methoxyethyl acrylate) are prepared employing controlled radical polymerization techniques. Linear backbones bearing atom transfer radical polymerization (ATRP) initiating sites are obtained by reversible addition-fragmentation chain transfer copolymerization of 2-methoxyethyl acrylate (MEA) and 2-(bromoisobutyryloxy)ethyl methacrylate (BriBuEMA) as well as 2-hydroxyethyl methacrylate and Br iBuEMA in a controlled manner. MEA is then grafted from the linear macroinitiators by Cu (I)-mediated ATRP. Fairly high molecular weights (>120 000 Da) and low polydispersity indices (1.17-1.38) are attained. Thermal investigations of the graft copolymers indicate the presence of the freezing bound water, and imply that the materials may exhibit blood compatibility..
261. Irakli Javakhishvili, Masaru Tanaka, Keiko Ogura, Katja Jankova, Søren Hvilsted, Synthesis of graft copolymers based on poly(2-methoxyethyl acrylate) and investigation of the associated water structure, Macromolecular rapid communications, 10.1002/marc.201100698, 33, 4, 319-325, 2012.02, Graft copolymers composed of poly(2-methoxyethyl acrylate) are prepared employing controlled radical polymerization techniques. Linear backbones bearing atom transfer radical polymerization (ATRP) initiating sites are obtained by reversible addition-fragmentation chain transfer copolymerization of 2-methoxyethyl acrylate (MEA) and 2-(bromoisobutyryloxy)ethyl methacrylate (BriBuEMA) as well as 2-hydroxyethyl methacrylate and Br iBuEMA in a controlled manner. MEA is then grafted from the linear macroinitiators by Cu (I)-mediated ATRP. Fairly high molecular weights (>120 000 Da) and low polydispersity indices (1.17-1.38) are attained. Thermal investigations of the graft copolymers indicate the presence of the freezing bound water, and imply that the materials may exhibit blood compatibility..
262. Irakli Javakhishvili, Masaru Tanaka, Keiko Ogura, Katja Jankova, Søren Hvilsted, Synthesis of graft copolymers based on poly(2-methoxyethyl acrylate) and investigation of the associated water structure, Macromolecular rapid communications, 10.1002/marc.201100698, 33, 4, 319-325, 2012.02, Graft copolymers composed of poly(2-methoxyethyl acrylate) are prepared employing controlled radical polymerization techniques. Linear backbones bearing atom transfer radical polymerization (ATRP) initiating sites are obtained by reversible addition-fragmentation chain transfer copolymerization of 2-methoxyethyl acrylate (MEA) and 2-(bromoisobutyryloxy)ethyl methacrylate (BriBuEMA) as well as 2-hydroxyethyl methacrylate and Br iBuEMA in a controlled manner. MEA is then grafted from the linear macroinitiators by Cu (I)-mediated ATRP. Fairly high molecular weights (>120 000 Da) and low polydispersity indices (1.17-1.38) are attained. Thermal investigations of the graft copolymers indicate the presence of the freezing bound water, and imply that the materials may exhibit blood compatibility..
263. Irakli Javakhishvili, Masaru Tanaka, Keiko Ogura, Katja Jankova, Soren Hvilsted, Synthesis of Graft Copolymers Based on Poly(2-Methoxyethyl Acrylate) and Investigation of the Associated Water Structure, MACROMOLECULAR RAPID COMMUNICATIONS, 10.1002/marc.201100698, 33, 4, 319-325, 2012.02, Graft copolymers composed of poly(2-methoxyethyl acrylate) are prepared employing controlled radical polymerization techniques. Linear backbones bearing atom transfer radical polymerization (ATRP) initiating sites are obtained by reversible additionfragmentation chain transfer copolymerization of 2-methoxyethyl acrylate (MEA) and 2-(bromoisobutyryloxy)ethyl methacrylate (BriBuEMA) as well as 2-hydroxyethyl methacrylate and BriBuEMA in a controlled manner . MEA is then grafted from the linear macroinitiators by Cu (I)-mediated ATRP. Fairly high molecular weights (>120 000 Da) and low polydispersity indices (1.171.38) are attained. Thermal investigations of the graft copolymers indicate the presence of the freezing bound water, and imply that the materials may exhibit blood compatibility..
264. Molecular Aggregation Structure of Polymer Materials at the Water Interface and Its Biocompatibility
Poly(2-methoxyethyl acrylate) (PMEA)-enriched surface was prepared by blending it with poly(methyl methacrylate) (PMMA) under appropriate annealing conditions. Atomic force microscopy revealed that the surface of the PMEA/PMMA blends was sufficiently flat and stable even in water. Contact angle of an air bubble on the blends in water decreased with increasing immersion time. These results indicate that aggregation states of polymer chains at the outermost region of the films were changed at the water interface. The blend surfaces showed excellent blood-compatibility by reducing platelet adhesion..
265. Masaru Tanaka, Thermal Characterization of Novel Polymers for Biomedical Applications, Netsu Sokutei, 151, 2012.
266. Masaru Tanaka, Thermal Characterization of Novel Polymers for Biomedical Applications, Netsu Sokutei, 151, 2012.
267. Masaru Tanaka, Thermal Characterization of Novel Polymers for Biomedical Applications, Netsu Sokutei, 151, 2012.
268. Yuko Miwa, Masaru Tanaka, Akira Mochizuki, Water structure and polymer dynamics in hydrated blood compatible polymers, Kobunshi Ronbunshu, 10.1295/koron.68.133, 68, 4, 133-146, 2011.04, Biomaterials with good blood compatibility are essential for new medical devices and/or therapies. Thus, there are many attempts to improve their performance for blood. To this end, biomaterials with a variety of surfaces have been proposed and some of them are already in clinical use. These surfaces can be classified into four groups; 1) super-hydrophilic surface, 2) micro-phase-separated domain surface, 3) biomembrane like surface and 4) bioactive-molecules incorporating surface. It is not clear, however, how these surfaces exhibit good blood compatibility except the case of 4). Recently, we found that poly (2-methoxyethyl acrylate) (PMEA), which does not belong to any of the classes mentioned above, exhibits excellent blood compatibility, but the mechanism of its good performance has not yet been fully understood. In order to gain an insight into its good performance, we have investigated the water structure in PMEA, and also polymer dynamics by solid-state NMR. Here, we discuss the role of water structure and polymer dynamics in determining good-compatibility of biomaterials from the viewpoint of water structure on the basis of various reports about the water structure in polymers investigated by DSC, FT-IR and NMR..
269. Yuko Miwa, Masaru Tanaka, Akira Mochizuki, Water structure and polymer dynamics in hydrated blood compatible polymers, KOBUNSHI RONBUNSHU, 10.1295/koron.68.133, 68, 4, 133-146, 2011.04, Biomaterials with good blood compatibility are essential for new medical devices and/or therapies. Thus, there are many attempts to improve their performance for blood. To this end, biomaterials with a variety of surfaces have been proposed and some of them are already in clinical use. These surfaces can be classified into four groups; 1) super-hydrophilic surface, 2) micro-phase-separated domain surface, 3) biomembrane like surface and 4) bioactive-molecules incorporating surface. It is not clear, however, how these surfaces exhibit good blood compatibility except the case of 4). Recently, we found that poly (2-methoxyethyl acrylate) (PMEA), which does not belong to any of the classes mentioned above, exhibits excellent blood compatibility, but the mechanism of its good performance has not yet been fully understood. In order to gain an insight into its good performance, we have investigated the water structure in PMEA, and also polymer dynamics by solid-state NMR. Here, we discuss the role of water structure and polymer dynamics in determining good-compatibility of biomaterials from the viewpoint of water structure on the basis of various reports about the water structure in polymers investigated by DSC, FT-IR and NMR..
270. Yuko Miwa, Masaru Tanaka, Akira Mochizuki, Water structure and polymer dynamics in hydrated blood compatible polymers, KOBUNSHI RONBUNSHU, 10.1295/koron.68.133, 68, 4, 133-146, 2011.04, Biomaterials with good blood compatibility are essential for new medical devices and/or therapies. Thus, there are many attempts to improve their performance for blood. To this end, biomaterials with a variety of surfaces have been proposed and some of them are already in clinical use. These surfaces can be classified into four groups; 1) super-hydrophilic surface, 2) micro-phase-separated domain surface, 3) biomembrane like surface and 4) bioactive-molecules incorporating surface. It is not clear, however, how these surfaces exhibit good blood compatibility except the case of 4). Recently, we found that poly (2-methoxyethyl acrylate) (PMEA), which does not belong to any of the classes mentioned above, exhibits excellent blood compatibility, but the mechanism of its good performance has not yet been fully understood. In order to gain an insight into its good performance, we have investigated the water structure in PMEA, and also polymer dynamics by solid-state NMR. Here, we discuss the role of water structure and polymer dynamics in determining good-compatibility of biomaterials from the viewpoint of water structure on the basis of various reports about the water structure in polymers investigated by DSC, FT-IR and NMR..
271. Masaru Tanaka, Design of novel 2D and 3D biointerfaces using self-organization to control cell behavior, Biochimica et Biophysica Acta - General Subjects, 10.1016/j.bbagen.2010.10.002, 1810, 3, 251-258, 2011.03, Background: The design of biocompatible 2D surfaces and 3D nano/micro topographies based on self-organization has a variety of potential applications in medical devices and tissue engineering. We have reported that biocompatible 2D surface using poly(2-methoxyethyl acrylate) (PMEA) and honeycomb-patterned 3D films with regular interconnected pores that is formed by self-organization. Scope of Review: We highlight that 1) the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of other polymers and 2) the reasons that 3D films exerted a strong influence on normal, cancer and stem cell morphology, proliferation, differentiation, cytoskeleton, focal adhesion, and functions including matrix production profiles. Major Conclusions: 1) We hypothesized that intermediate water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent biocompatibility. 2) The cellular response to 3D films originates from the regularly aligned adsorbed proteins determined by the pore structure of the film. General Significance: It is expected that combining the biocompatible 2D surfaces and 3D nano/micro topographies will provide an effective strategy for medical devices and tissue engineering scaffolds. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine..
272. Toyoaki Hirata, Hisao Matsuno, Masaru Tanaka, Keiji Tanaka, Surface segregation of poly(2-methoxyethyl acrylate) in a mixture with poly(methyl methacrylate), Physical Chemistry Chemical Physics, 10.1039/c0cp02101f, 13, 11, 4928-4934, 2011.03, Poly(2-methoxyethyl acrylate) (PMEA) exhibits excellent blood compatibility. To understand why such a surface functionality exists, the surface of PMEA should be characterized in detail, structurally and dynamically, under not only ambient conditions, but also in water. However, a thin film of PMEA supported on a solid substrate can be easily broken, namely it is dewetted. Our strategy to overcome this difficulty is to mix PMEA with poly(methyl methacrylate) (PMMA). Differential scanning calorimetry and cloud point measurements revealed that the PMEA/PMMA blend has a phase diagram with a lower critical solution temperature. The blend surface was also characterized by X-ray photoelectron spectroscopy in conjunction with microscopic observations. Although PMEA is preferentially segregated over PMMA at the blend surface due to its lower surface free energy, the extent of segregation in the as-prepared films was not sufficient to cover the surface. Annealing the blend film at an appropriate temperature, higher than the glass transition temperature and lower than the phase-separation temperature of the blend, enabled us to prepare a stable and flat surface that was perfectly covered with PMEA..
273. Masaru Tanaka, Design of novel 2D and 3D biointerfaces using self-organization to control cell behavior, Biochimica et Biophysica Acta - General Subjects, 10.1016/j.bbagen.2010.10.002, 1810, 3, 251-258, 2011.03, Background: The design of biocompatible 2D surfaces and 3D nano/micro topographies based on self-organization has a variety of potential applications in medical devices and tissue engineering. We have reported that biocompatible 2D surface using poly(2-methoxyethyl acrylate) (PMEA) and honeycomb-patterned 3D films with regular interconnected pores that is formed by self-organization. Scope of Review: We highlight that 1) the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of other polymers and 2) the reasons that 3D films exerted a strong influence on normal, cancer and stem cell morphology, proliferation, differentiation, cytoskeleton, focal adhesion, and functions including matrix production profiles. Major Conclusions: 1) We hypothesized that intermediate water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent biocompatibility. 2) The cellular response to 3D films originates from the regularly aligned adsorbed proteins determined by the pore structure of the film. General Significance: It is expected that combining the biocompatible 2D surfaces and 3D nano/micro topographies will provide an effective strategy for medical devices and tissue engineering scaffolds. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine..
274. Toyoaki Hirata, Hisao Matsuno, Masaru Tanaka, Keiji Tanaka, Surface segregation of poly(2-methoxyethyl acrylate) in a mixture with poly(methyl methacrylate), Physical Chemistry Chemical Physics, 10.1039/c0cp02101f, 13, 11, 4928-4934, 2011.03, Poly(2-methoxyethyl acrylate) (PMEA) exhibits excellent blood compatibility. To understand why such a surface functionality exists, the surface of PMEA should be characterized in detail, structurally and dynamically, under not only ambient conditions, but also in water. However, a thin film of PMEA supported on a solid substrate can be easily broken, namely it is dewetted. Our strategy to overcome this difficulty is to mix PMEA with poly(methyl methacrylate) (PMMA). Differential scanning calorimetry and cloud point measurements revealed that the PMEA/PMMA blend has a phase diagram with a lower critical solution temperature. The blend surface was also characterized by X-ray photoelectron spectroscopy in conjunction with microscopic observations. Although PMEA is preferentially segregated over PMMA at the blend surface due to its lower surface free energy, the extent of segregation in the as-prepared films was not sufficient to cover the surface. Annealing the blend film at an appropriate temperature, higher than the glass transition temperature and lower than the phase-separation temperature of the blend, enabled us to prepare a stable and flat surface that was perfectly covered with PMEA..
275. Masaru Tanaka, Design of novel 2D and 3D biointerfaces using self-organization to control cell behavior, Biochimica et Biophysica Acta - General Subjects, 10.1016/j.bbagen.2010.10.002, 1810, 3, 251-258, 2011.03, Background: The design of biocompatible 2D surfaces and 3D nano/micro topographies based on self-organization has a variety of potential applications in medical devices and tissue engineering. We have reported that biocompatible 2D surface using poly(2-methoxyethyl acrylate) (PMEA) and honeycomb-patterned 3D films with regular interconnected pores that is formed by self-organization. Scope of Review: We highlight that 1) the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of other polymers and 2) the reasons that 3D films exerted a strong influence on normal, cancer and stem cell morphology, proliferation, differentiation, cytoskeleton, focal adhesion, and functions including matrix production profiles. Major Conclusions: 1) We hypothesized that intermediate water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent biocompatibility. 2) The cellular response to 3D films originates from the regularly aligned adsorbed proteins determined by the pore structure of the film. General Significance: It is expected that combining the biocompatible 2D surfaces and 3D nano/micro topographies will provide an effective strategy for medical devices and tissue engineering scaffolds. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine..
276. Toyoaki Hirata, Hisao Matsuno, Masaru Tanaka, Keiji Tanaka, Surface segregation of poly(2-methoxyethyl acrylate) in a mixture with poly(methyl methacrylate), Physical Chemistry Chemical Physics, 10.1039/c0cp02101f, 13, 11, 4928-4934, 2011.03, Poly(2-methoxyethyl acrylate) (PMEA) exhibits excellent blood compatibility. To understand why such a surface functionality exists, the surface of PMEA should be characterized in detail, structurally and dynamically, under not only ambient conditions, but also in water. However, a thin film of PMEA supported on a solid substrate can be easily broken, namely it is dewetted. Our strategy to overcome this difficulty is to mix PMEA with poly(methyl methacrylate) (PMMA). Differential scanning calorimetry and cloud point measurements revealed that the PMEA/PMMA blend has a phase diagram with a lower critical solution temperature. The blend surface was also characterized by X-ray photoelectron spectroscopy in conjunction with microscopic observations. Although PMEA is preferentially segregated over PMMA at the blend surface due to its lower surface free energy, the extent of segregation in the as-prepared films was not sufficient to cover the surface. Annealing the blend film at an appropriate temperature, higher than the glass transition temperature and lower than the phase-separation temperature of the blend, enabled us to prepare a stable and flat surface that was perfectly covered with PMEA..
277. Masaru Tanaka, Design of novel 2D and 3D biointerfaces using self-organization to control cell behavior, BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS, 10.1016/j.bbagen.2010.10.002, 1810, 3, 251-258, 2011.03, Background: The design of biocompatible 2D surfaces and 3D nano/micro topographies based on self-organization has a variety of potential applications in medical devices and tissue engineering. We have reported that biocompatible 2D surface using poly(2-methoxyethyl acrylate) (PMEA) and honeycomb-patterned 3D films with regular interconnected pores that is formed by self-organization.
Scope of Review: We highlight that 1) the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of other polymers and 2) the reasons that 3D films exerted a strong influence on normal, cancer and stem cell morphology, proliferation, differentiation, cytoskeleton, focal adhesion, and functions including matrix production profiles.
Major Conclusions: 1) We hypothesized that intermediate water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent biocompatibility. 2) The cellular response to 3D films originates from the regularly aligned adsorbed proteins determined by the pore structure of the film.
General Significance: It is expected that combining the biocompatible 2D surfaces and 3D nano/micro topographies will provide an effective strategy for medical devices and tissue engineering scaffolds.
This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine. (C) 2010 Elsevier B.V. All rights reserved..
278. Yuko Miwa, Hiroyuki Ishida, Masaru Tanaka, Akira Mochizuki, 2H-NMR and 13C-NMR study of the hydration behavior of poly(2-methoxyethyl acrylate), poly(2-hydroxyethyl methacrylate) and poly(tetrahydrofurfuryl acrylate) in relation to their blood compatibility as biomaterials, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X489682, 21, 14, 1911-1924, 2010.10, We recorded 2H-NMR spectra of (deuterated) water in the presence of poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA). The observed 2H-NMR peak intensities varied substantially with water content and temperature, depending upon either strong binding to polymer surface or suppressed peaks due to freezing. Indeed, 2H-NMR signals in the presence of PHEMA were strongly dependent upon its water content, while those of hydrated PMEA and PTHFA remained unchanged even at -30°C and -20°C. The latter were considerably broadened at -50°C and -30°C, respectively, due to freezing water from the super-cooled state. As a result, the states of the water molecules in PMEA and PTHFA can be classified into three types; free, freezing bound and non-freezing water molecules. The states of the water in PHEMA depend on the water content, and the water can be classified into two types, free and non-freezing water, which exhibit rapid fluctuation and restricted mobility because of the presence of macromolecules, respectively. A kind of freezing bound water, however, should exist in PHEMA. This is also consistent with the substantially decreased 2H spin-lattice relaxation times of hydrated PHEMA as compared with those of PMEA or PTHFA. It is also interesting to note that the flexibility of bound water or polymer (PMEA > PTHFA > PHEMA) is related to a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system. Therefore, it is naturally recognized that such differential polymer dynamics might be responsible for concomitant changes in structure and dynamics of surrounding water molecules in the vicinity of constituent polymer network..
279. Masaru Tanaka, Akira Mochizuki, Clarification of the blood compatibility mechanism by controlling the water structure at the blood-poly(meth)acrylate interface, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X517220, 21, 14, 1849-1863, 2010.10, In previous studies, we reported that poly(2-methoxyethyl acrylate) (PMEA) exhibited excellent blood compatibility, although it has a simple chemical structure. Since then, we have been investigating the reasons for its blood compatibility. In this short review, we consider the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(meth)acrylate analogs as reference polymers. The hydrated water in PMEA could be classified into three types; free water (or freezing water), freezing-bound water (or intermediate water), and non-freezing water (or non-freezing-bound water). We found that hydrated PMEA possessed a unique water structure, observed as cold crystallization of water in differential scanning calorimetry (DSC). Cold crystallization is interpreted as ice formation at low temperature, an attribute of freezing-bound water in PMEA. The cold crystallization peak was observed for hydrated poly(ethylene glycol) (PEG), poly(vinyl methyl ether) (PVME), polyvinylpyrrolidone (PVP), poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(tetrahydrofurfuryl acrylate) (PTHFA), and newly synthesized poly(2-(2-ethoxyethoxy)ethyl acrylate), as well as various proteins and polysaccharides, which are well-known biocompatible polymers. On the other hand, cold crystallization of water was not observed in hydrated PHEMA and PMEA analogous polymers, which do not show excellent blood compatibility. Based on these findings, we hypothesized that freezing-bound water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent blood compatibility of PMEA..
280. Takashige Sato, Masaru Tanaka, Sadaaki Yamamoto, Emiko Ito, Kyoko Shimizu, Yasuyuki Igarashi, Masatsugu Shimomura, Jin Ichi Inokuchi, Effect of honeycomb-patterned surface topography on the function of mesenteric adipocytes, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X500615, 21, 14, 1947-1956, 2010.10, Excessive accumulation of visceral adipose tissue, particularly mesenteric adipose tissue, is one of the most important factors in the pathogenesis of the metabolic syndrome. We previously developed a system for physiologically differentiating rat mesenteric-stromal vascular cells (mSVCs) to mesenteric-visceral adipocytes (mVACs) and are currently implementing various approaches to elucidate the details of the pathophysiology of mVACs. However, there is a critical problem to overcome, namely, that mature mVACs detach from the culture dishes and lose their function after approx. 10 days in culture. Therefore, we examined a culture of mSVCs on self-organized honeycomb-patterned films (honeycomb films) in order to establish a long-term culture for mVACs. The honeycomb films with highly regular porous structures can be prepared under humid casting conditions. These films can be prepared with ease, at a low cost and without any limitations pertaining to the availability of materials for the scaffold. As a result, mSVCs differentiated to mVACs and maintained their function for the secretion of adiponectin on the honeycomb films for at least 40 days. In addition, we investigated the influence of the pore size of the honeycomb films on mVAC behavior. We found that a honeycomb film with a pore size of 20 μm showed the highest mVAC function and optimum size for the long-term culture of mVACs. Thus, we established a long-term culture system for mVACs using the honeycomb films. We believe that this culture system will contribute to the understanding of the pathophysiology of mVACs and to the evaluation of drug candidates for the metabolic syndrome..
281. Shigeaki Morita, Masaru Tanaka, Kuniyuki Kitagawa, Yukihiro Ozaki, Hydration structure of poly(2-methoxyethyl acrylate)
Comparison with a 2-methoxyethyl acetate model monomer, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X494613, 21, 14, 1925-1935, 2010.10, We have previously reported the hydration structure of a poly(2-methoxyethyl acrylate) (PMEA) antithrombogenic material. In the present study, the hydration structure of a 2-methoxyethyl acetate (MEAc) model monomer for PMEA was explored by means of attenuated total reflection infrared (ATR-IR) spectroscopy and differential scanning calorimetry (DSC). Water in MEAc does not show an evidence for cold crystallization by DSC, while it was found by ATR-IR spectroscopy that MEAc has a hydration structure similar to that of PMEA at a functional group level. Three different types of hydrated water, tightly bound water, loosely bound water and scarcely bound water, were identified in MEAc, as well as PMEA. It was suggested from the present study that the localized and concentrated water cluster having the three types of hydration structure on the surface of PMEA plays an important role in the biocompatibility..
282. Masaru Tanaka, Akira Mochizuki, Hiromi Kitano, Journal of Biomaterials Science, Polymer Edition
Preface, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X527256, 21, 14, 1827-1829, 2010.10.
283. Yasumitsu Uraki, Chinatsu Matsumoto, Takuro Hirai, Yutaka Tamai, Makiko Enoki, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Mechanical effect of acetic acid lignin adsorption on honeycomb-patterned cellulosic films, Journal of Wood Chemistry and Technology, 10.1080/02773811003746709, 30, 4, 348-359, 2010.10, We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall. The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions..
284. Akira Mochizuki, Maki Kimura, Ayano Ina, Yuka Tomono, Masaru Tanaka, Study on the water structure and blood compatibility of poly(acryloylmorpholine-r-butyl methacrylate), Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X489321, 21, 14, 1895-1910, 2010.10, We have been studying the blood compatibility of polymeric materials from the viewpoint of their water structure, and have proposed that freezable water interacting with polymer molecules plays an important role in determining that compatibility. As we found that water-soluble poly(acryloylmorpholine) interacted with water, resulting in the formation of 'bound water', we newly prepared water-non-soluble poly(acryloylmorpholine-r-butyl methacrylate) (denoted as ACMO co-polymer) with various composition ratios. In addition, the properties of a co-polymer based on N,N-diethylacrylamide (DEA co-polymer), where DEA has a similar chemical structure to ACMO, except that DEA has no ether oxygen, were compared with that of the ACMO co-polymer. Contact angle and DSC analysis revealed that an increase in the content of an N-substituted acrylamide unit in the co-polymers enhanced the hydrophilicity of the polymer and that the hydrophilicity of the ACMO co-polymer was stronger than that of the DEA co-polymer. As for the water structure, it was found that the ACMO co-polymer had a lot of bound water compared to the DEA co-polymer. The difference in these properties between the ACMO and DEA co-polymers was due to the ether oxygen of the morpholine group. At the same time, in vitro blood compatibility tests showed that the ACMO co-polymer exhibited a much better performance than the DEA co-polymer. The water structure and blood compatibility is discussed in detail..
285. Tatsuko Hatakeyama, Masaru Tanaka, Hyoe Hatakeyama, Thermal properties of freezing bound water restrained by polysaccharides, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X486946, 21, 14, 1865-1875, 2010.10, This review focuses on the thermal properties of bound water restrained by various kinds of polysaccharides and several synthetic polymers. The characteristic features of freezing bound water which is closely related with biocompatibility of polymers are summarized based on results obtained by differential scanning calorimetry. Glass transition, cold crystallization and melting of water-polysaccharide systems were observed. Three kinds of water, non-freezing, freezing bound and free water, were quantified from the enthalpy of melting of water in the system. Freezing bound water restrained by polysaccharides is in a metastable state. The equilibrium melting temperature of freezing bound water is lower than 0°C and the temperature decreases with decreasing water content. Nucleation and growth rate of freezing bound water were calculated from isothermal crystallization and the values were compared with those of free water..
286. Yuko Miwa, Hiroyuki Ishida, Masaru Tanaka, Akira Mochizuki, 2H-NMR and 13C-NMR study of the hydration behavior of poly(2-methoxyethyl acrylate), poly(2-hydroxyethyl methacrylate) and poly(tetrahydrofurfuryl acrylate) in relation to their blood compatibility as biomaterials, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X489682, 21, 14, 1911-1924, 2010.10, We recorded 2H-NMR spectra of (deuterated) water in the presence of poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA). The observed 2H-NMR peak intensities varied substantially with water content and temperature, depending upon either strong binding to polymer surface or suppressed peaks due to freezing. Indeed, 2H-NMR signals in the presence of PHEMA were strongly dependent upon its water content, while those of hydrated PMEA and PTHFA remained unchanged even at -30°C and -20°C. The latter were considerably broadened at -50°C and -30°C, respectively, due to freezing water from the super-cooled state. As a result, the states of the water molecules in PMEA and PTHFA can be classified into three types; free, freezing bound and non-freezing water molecules. The states of the water in PHEMA depend on the water content, and the water can be classified into two types, free and non-freezing water, which exhibit rapid fluctuation and restricted mobility because of the presence of macromolecules, respectively. A kind of freezing bound water, however, should exist in PHEMA. This is also consistent with the substantially decreased 2H spin-lattice relaxation times of hydrated PHEMA as compared with those of PMEA or PTHFA. It is also interesting to note that the flexibility of bound water or polymer (PMEA > PTHFA > PHEMA) is related to a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system. Therefore, it is naturally recognized that such differential polymer dynamics might be responsible for concomitant changes in structure and dynamics of surrounding water molecules in the vicinity of constituent polymer network..
287. Masaru Tanaka, Akira Mochizuki, Clarification of the blood compatibility mechanism by controlling the water structure at the blood-poly(meth)acrylate interface, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X517220, 21, 14, 1849-1863, 2010.10, In previous studies, we reported that poly(2-methoxyethyl acrylate) (PMEA) exhibited excellent blood compatibility, although it has a simple chemical structure. Since then, we have been investigating the reasons for its blood compatibility. In this short review, we consider the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(meth)acrylate analogs as reference polymers. The hydrated water in PMEA could be classified into three types; free water (or freezing water), freezing-bound water (or intermediate water), and non-freezing water (or non-freezing-bound water). We found that hydrated PMEA possessed a unique water structure, observed as cold crystallization of water in differential scanning calorimetry (DSC). Cold crystallization is interpreted as ice formation at low temperature, an attribute of freezing-bound water in PMEA. The cold crystallization peak was observed for hydrated poly(ethylene glycol) (PEG), poly(vinyl methyl ether) (PVME), polyvinylpyrrolidone (PVP), poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(tetrahydrofurfuryl acrylate) (PTHFA), and newly synthesized poly(2-(2-ethoxyethoxy)ethyl acrylate), as well as various proteins and polysaccharides, which are well-known biocompatible polymers. On the other hand, cold crystallization of water was not observed in hydrated PHEMA and PMEA analogous polymers, which do not show excellent blood compatibility. Based on these findings, we hypothesized that freezing-bound water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent blood compatibility of PMEA..
288. Takashige Sato, Masaru Tanaka, Sadaaki Yamamoto, Emiko Ito, Kyoko Shimizu, Yasuyuki Igarashi, Masatsugu Shimomura, Jin Ichi Inokuchi, Effect of honeycomb-patterned surface topography on the function of mesenteric adipocytes, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X500615, 21, 14, 1947-1956, 2010.10, Excessive accumulation of visceral adipose tissue, particularly mesenteric adipose tissue, is one of the most important factors in the pathogenesis of the metabolic syndrome. We previously developed a system for physiologically differentiating rat mesenteric-stromal vascular cells (mSVCs) to mesenteric-visceral adipocytes (mVACs) and are currently implementing various approaches to elucidate the details of the pathophysiology of mVACs. However, there is a critical problem to overcome, namely, that mature mVACs detach from the culture dishes and lose their function after approx. 10 days in culture. Therefore, we examined a culture of mSVCs on self-organized honeycomb-patterned films (honeycomb films) in order to establish a long-term culture for mVACs. The honeycomb films with highly regular porous structures can be prepared under humid casting conditions. These films can be prepared with ease, at a low cost and without any limitations pertaining to the availability of materials for the scaffold. As a result, mSVCs differentiated to mVACs and maintained their function for the secretion of adiponectin on the honeycomb films for at least 40 days. In addition, we investigated the influence of the pore size of the honeycomb films on mVAC behavior. We found that a honeycomb film with a pore size of 20 μm showed the highest mVAC function and optimum size for the long-term culture of mVACs. Thus, we established a long-term culture system for mVACs using the honeycomb films. We believe that this culture system will contribute to the understanding of the pathophysiology of mVACs and to the evaluation of drug candidates for the metabolic syndrome..
289. Shigeaki Morita, Masaru Tanaka, Kuniyuki Kitagawa, Yukihiro Ozaki, Hydration structure of poly(2-methoxyethyl acrylate)
Comparison with a 2-methoxyethyl acetate model monomer, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X494613, 21, 14, 1925-1935, 2010.10, We have previously reported the hydration structure of a poly(2-methoxyethyl acrylate) (PMEA) antithrombogenic material. In the present study, the hydration structure of a 2-methoxyethyl acetate (MEAc) model monomer for PMEA was explored by means of attenuated total reflection infrared (ATR-IR) spectroscopy and differential scanning calorimetry (DSC). Water in MEAc does not show an evidence for cold crystallization by DSC, while it was found by ATR-IR spectroscopy that MEAc has a hydration structure similar to that of PMEA at a functional group level. Three different types of hydrated water, tightly bound water, loosely bound water and scarcely bound water, were identified in MEAc, as well as PMEA. It was suggested from the present study that the localized and concentrated water cluster having the three types of hydration structure on the surface of PMEA plays an important role in the biocompatibility..
290. Masaru Tanaka, Akira Mochizuki, Hiromi Kitano, Journal of Biomaterials Science, Polymer Edition
Preface, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X527256, 21, 14, 1827-1829, 2010.10.
291. Yasumitsu Uraki, Chinatsu Matsumoto, Takuro Hirai, Yutaka Tamai, Makiko Enoki, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Mechanical effect of acetic acid lignin adsorption on honeycomb-patterned cellulosic films, Journal of Wood Chemistry and Technology, 10.1080/02773811003746709, 30, 4, 348-359, 2010.10, We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall. The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions..
292. Akira Mochizuki, Maki Kimura, Ayano Ina, Yuka Tomono, Masaru Tanaka, Study on the water structure and blood compatibility of poly(acryloylmorpholine-r-butyl methacrylate), Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X489321, 21, 14, 1895-1910, 2010.10, We have been studying the blood compatibility of polymeric materials from the viewpoint of their water structure, and have proposed that freezable water interacting with polymer molecules plays an important role in determining that compatibility. As we found that water-soluble poly(acryloylmorpholine) interacted with water, resulting in the formation of 'bound water', we newly prepared water-non-soluble poly(acryloylmorpholine-r-butyl methacrylate) (denoted as ACMO co-polymer) with various composition ratios. In addition, the properties of a co-polymer based on N,N-diethylacrylamide (DEA co-polymer), where DEA has a similar chemical structure to ACMO, except that DEA has no ether oxygen, were compared with that of the ACMO co-polymer. Contact angle and DSC analysis revealed that an increase in the content of an N-substituted acrylamide unit in the co-polymers enhanced the hydrophilicity of the polymer and that the hydrophilicity of the ACMO co-polymer was stronger than that of the DEA co-polymer. As for the water structure, it was found that the ACMO co-polymer had a lot of bound water compared to the DEA co-polymer. The difference in these properties between the ACMO and DEA co-polymers was due to the ether oxygen of the morpholine group. At the same time, in vitro blood compatibility tests showed that the ACMO co-polymer exhibited a much better performance than the DEA co-polymer. The water structure and blood compatibility is discussed in detail..
293. Tatsuko Hatakeyama, Masaru Tanaka, Hyoe Hatakeyama, Thermal properties of freezing bound water restrained by polysaccharides, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X486946, 21, 14, 1865-1875, 2010.10, This review focuses on the thermal properties of bound water restrained by various kinds of polysaccharides and several synthetic polymers. The characteristic features of freezing bound water which is closely related with biocompatibility of polymers are summarized based on results obtained by differential scanning calorimetry. Glass transition, cold crystallization and melting of water-polysaccharide systems were observed. Three kinds of water, non-freezing, freezing bound and free water, were quantified from the enthalpy of melting of water in the system. Freezing bound water restrained by polysaccharides is in a metastable state. The equilibrium melting temperature of freezing bound water is lower than 0°C and the temperature decreases with decreasing water content. Nucleation and growth rate of freezing bound water were calculated from isothermal crystallization and the values were compared with those of free water..
294. Yuko Miwa, Hiroyuki Ishida, Masaru Tanaka, Akira Mochizuki, 2H-NMR and 13C-NMR study of the hydration behavior of poly(2-methoxyethyl acrylate), poly(2-hydroxyethyl methacrylate) and poly(tetrahydrofurfuryl acrylate) in relation to their blood compatibility as biomaterials, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X489682, 21, 14, 1911-1924, 2010.10, We recorded 2H-NMR spectra of (deuterated) water in the presence of poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA). The observed 2H-NMR peak intensities varied substantially with water content and temperature, depending upon either strong binding to polymer surface or suppressed peaks due to freezing. Indeed, 2H-NMR signals in the presence of PHEMA were strongly dependent upon its water content, while those of hydrated PMEA and PTHFA remained unchanged even at -30°C and -20°C. The latter were considerably broadened at -50°C and -30°C, respectively, due to freezing water from the super-cooled state. As a result, the states of the water molecules in PMEA and PTHFA can be classified into three types; free, freezing bound and non-freezing water molecules. The states of the water in PHEMA depend on the water content, and the water can be classified into two types, free and non-freezing water, which exhibit rapid fluctuation and restricted mobility because of the presence of macromolecules, respectively. A kind of freezing bound water, however, should exist in PHEMA. This is also consistent with the substantially decreased 2H spin-lattice relaxation times of hydrated PHEMA as compared with those of PMEA or PTHFA. It is also interesting to note that the flexibility of bound water or polymer (PMEA > PTHFA > PHEMA) is related to a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system. Therefore, it is naturally recognized that such differential polymer dynamics might be responsible for concomitant changes in structure and dynamics of surrounding water molecules in the vicinity of constituent polymer network..
295. Masaru Tanaka, Akira Mochizuki, Clarification of the blood compatibility mechanism by controlling the water structure at the blood-poly(meth)acrylate interface, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X517220, 21, 14, 1849-1863, 2010.10, In previous studies, we reported that poly(2-methoxyethyl acrylate) (PMEA) exhibited excellent blood compatibility, although it has a simple chemical structure. Since then, we have been investigating the reasons for its blood compatibility. In this short review, we consider the reasons for this compatibility by comparing the structure of water in hydrated PMEA to the water structure of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(meth)acrylate analogs as reference polymers. The hydrated water in PMEA could be classified into three types; free water (or freezing water), freezing-bound water (or intermediate water), and non-freezing water (or non-freezing-bound water). We found that hydrated PMEA possessed a unique water structure, observed as cold crystallization of water in differential scanning calorimetry (DSC). Cold crystallization is interpreted as ice formation at low temperature, an attribute of freezing-bound water in PMEA. The cold crystallization peak was observed for hydrated poly(ethylene glycol) (PEG), poly(vinyl methyl ether) (PVME), polyvinylpyrrolidone (PVP), poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(tetrahydrofurfuryl acrylate) (PTHFA), and newly synthesized poly(2-(2-ethoxyethoxy)ethyl acrylate), as well as various proteins and polysaccharides, which are well-known biocompatible polymers. On the other hand, cold crystallization of water was not observed in hydrated PHEMA and PMEA analogous polymers, which do not show excellent blood compatibility. Based on these findings, we hypothesized that freezing-bound water, which prevents the biocomponents from directly contacting the polymer surface or non-freezing water on the polymer surface, plays an important role in the excellent blood compatibility of PMEA..
296. Takashige Sato, Masaru Tanaka, Sadaaki Yamamoto, Emiko Ito, Kyoko Shimizu, Yasuyuki Igarashi, Masatsugu Shimomura, Jin Ichi Inokuchi, Effect of honeycomb-patterned surface topography on the function of mesenteric adipocytes, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X500615, 21, 14, 1947-1956, 2010.10, Excessive accumulation of visceral adipose tissue, particularly mesenteric adipose tissue, is one of the most important factors in the pathogenesis of the metabolic syndrome. We previously developed a system for physiologically differentiating rat mesenteric-stromal vascular cells (mSVCs) to mesenteric-visceral adipocytes (mVACs) and are currently implementing various approaches to elucidate the details of the pathophysiology of mVACs. However, there is a critical problem to overcome, namely, that mature mVACs detach from the culture dishes and lose their function after approx. 10 days in culture. Therefore, we examined a culture of mSVCs on self-organized honeycomb-patterned films (honeycomb films) in order to establish a long-term culture for mVACs. The honeycomb films with highly regular porous structures can be prepared under humid casting conditions. These films can be prepared with ease, at a low cost and without any limitations pertaining to the availability of materials for the scaffold. As a result, mSVCs differentiated to mVACs and maintained their function for the secretion of adiponectin on the honeycomb films for at least 40 days. In addition, we investigated the influence of the pore size of the honeycomb films on mVAC behavior. We found that a honeycomb film with a pore size of 20 μm showed the highest mVAC function and optimum size for the long-term culture of mVACs. Thus, we established a long-term culture system for mVACs using the honeycomb films. We believe that this culture system will contribute to the understanding of the pathophysiology of mVACs and to the evaluation of drug candidates for the metabolic syndrome..
297. Shigeaki Morita, Masaru Tanaka, Kuniyuki Kitagawa, Yukihiro Ozaki, Hydration structure of poly(2-methoxyethyl acrylate)
Comparison with a 2-methoxyethyl acetate model monomer, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X494613, 21, 14, 1925-1935, 2010.10, We have previously reported the hydration structure of a poly(2-methoxyethyl acrylate) (PMEA) antithrombogenic material. In the present study, the hydration structure of a 2-methoxyethyl acetate (MEAc) model monomer for PMEA was explored by means of attenuated total reflection infrared (ATR-IR) spectroscopy and differential scanning calorimetry (DSC). Water in MEAc does not show an evidence for cold crystallization by DSC, while it was found by ATR-IR spectroscopy that MEAc has a hydration structure similar to that of PMEA at a functional group level. Three different types of hydrated water, tightly bound water, loosely bound water and scarcely bound water, were identified in MEAc, as well as PMEA. It was suggested from the present study that the localized and concentrated water cluster having the three types of hydration structure on the surface of PMEA plays an important role in the biocompatibility..
298. Masaru Tanaka, Akira Mochizuki, Hiromi Kitano, Journal of Biomaterials Science, Polymer Edition
Preface, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X527256, 21, 14, 1827-1829, 2010.10.
299. Yasumitsu Uraki, Chinatsu Matsumoto, Takuro Hirai, Yutaka Tamai, Makiko Enoki, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Mechanical effect of acetic acid lignin adsorption on honeycomb-patterned cellulosic films, Journal of Wood Chemistry and Technology, 10.1080/02773811003746709, 30, 4, 348-359, 2010.10, We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall. The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions..
300. Akira Mochizuki, Maki Kimura, Ayano Ina, Yuka Tomono, Masaru Tanaka, Study on the water structure and blood compatibility of poly(acryloylmorpholine-r-butyl methacrylate), Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X489321, 21, 14, 1895-1910, 2010.10, We have been studying the blood compatibility of polymeric materials from the viewpoint of their water structure, and have proposed that freezable water interacting with polymer molecules plays an important role in determining that compatibility. As we found that water-soluble poly(acryloylmorpholine) interacted with water, resulting in the formation of 'bound water', we newly prepared water-non-soluble poly(acryloylmorpholine-r-butyl methacrylate) (denoted as ACMO co-polymer) with various composition ratios. In addition, the properties of a co-polymer based on N,N-diethylacrylamide (DEA co-polymer), where DEA has a similar chemical structure to ACMO, except that DEA has no ether oxygen, were compared with that of the ACMO co-polymer. Contact angle and DSC analysis revealed that an increase in the content of an N-substituted acrylamide unit in the co-polymers enhanced the hydrophilicity of the polymer and that the hydrophilicity of the ACMO co-polymer was stronger than that of the DEA co-polymer. As for the water structure, it was found that the ACMO co-polymer had a lot of bound water compared to the DEA co-polymer. The difference in these properties between the ACMO and DEA co-polymers was due to the ether oxygen of the morpholine group. At the same time, in vitro blood compatibility tests showed that the ACMO co-polymer exhibited a much better performance than the DEA co-polymer. The water structure and blood compatibility is discussed in detail..
301. Tatsuko Hatakeyama, Masaru Tanaka, Hyoe Hatakeyama, Thermal properties of freezing bound water restrained by polysaccharides, Journal of Biomaterials Science, Polymer Edition, 10.1163/092050610X486946, 21, 14, 1865-1875, 2010.10, This review focuses on the thermal properties of bound water restrained by various kinds of polysaccharides and several synthetic polymers. The characteristic features of freezing bound water which is closely related with biocompatibility of polymers are summarized based on results obtained by differential scanning calorimetry. Glass transition, cold crystallization and melting of water-polysaccharide systems were observed. Three kinds of water, non-freezing, freezing bound and free water, were quantified from the enthalpy of melting of water in the system. Freezing bound water restrained by polysaccharides is in a metastable state. The equilibrium melting temperature of freezing bound water is lower than 0°C and the temperature decreases with decreasing water content. Nucleation and growth rate of freezing bound water were calculated from isothermal crystallization and the values were compared with those of free water..
302. Hiroshi Ishihata, Masaru Tanaka, Nagayoshi Iwama, Masahiro Ara, Mitsuru Shimonishi, Masaru Nagamine, Noriaki Murakami, Sousuke Kanaya, Eiji Nemoto, Hidetoshi Shimauchi, Masatsugu Shimomura, Proliferation of periodontal ligament cells on biodegradable honeycomb film scaffold with unified micropore organization, Journal of Biomechanical Science and Engineering, 10.1299/jbse.5.252, 5, 3, 252-261, 2010.08, Tissue-engineered grafts using a scaffold can be used in treating periodontal disease; however, previous scaffolds for the cultivations of the periodontal ligament cells have been structurally incompatible with the morphological requirements of human periodontal tissue. Here, we describe a self-organized honeycomb-patterned film (honeycomb film) that acted as an appropriate scaffold for periodontal tissue regeneration. The honeycomb films were prepared from biodegradable poly(ε-caprolactone) with highly regular three-dimensional micropatterned surface topography by casting a polymer solution of water-immiscible solvent under humid conditions. To evaluate its performance in activating the proliferation and organizing of cells, we have demonstrated specific behaviors of the cultured periodontal ligament cells on the self-organized honeycomb structures in vitro. Fibroblast-like cells derived from the periodontal ligament of extracted human molar teeth were cultivated on three types of honeycomb films with 5-, 10-, and 15-μm pore sizes for 4 h to 42 d. Morphological observation of the cultured tissues at 4-72 h revealed that the pseudopodiums of cell bodies were attached to the pillars in the honeycomb structure. A certain number of cells shifted their cell bodies into the honeycomb structural lumen through the oscula of 10- and 15-μm pores. After 28 and 42 d, the cells were observed to have formed multiple layers; further, each cell had penetrated through the 10- and 15-μm pores in the honeycomb film. The morphological examination of the honeycomb film along with the pillar structures revealed that the scaffold was clusteringly arrayed with interconnected structures, remarkably enhanced proliferation, and extension of the cultured cells. We consider that the film can be applied in periodontal therapy for use as a scaffold for periodontal tissue regeneration..
303. Hiroshi Ishihata, Masaru Tanaka, Nagayoshi Iwama, Masahiro Ara, Mitsuru Shimonishi, Masaru Nagamine, Noriaki Murakami, Sousuke Kanaya, Eiji Nemoto, Hidetoshi Shimauchi, Masatsugu Shimomura, Proliferation of periodontal ligament cells on biodegradable honeycomb film scaffold with unified micropore organization, Journal of Biomechanical Science and Engineering, 10.1299/jbse.5.252, 5, 3, 252-261, 2010.08, Tissue-engineered grafts using a scaffold can be used in treating periodontal disease; however, previous scaffolds for the cultivations of the periodontal ligament cells have been structurally incompatible with the morphological requirements of human periodontal tissue. Here, we describe a self-organized honeycomb-patterned film (honeycomb film) that acted as an appropriate scaffold for periodontal tissue regeneration. The honeycomb films were prepared from biodegradable poly(ε-caprolactone) with highly regular three-dimensional micropatterned surface topography by casting a polymer solution of water-immiscible solvent under humid conditions. To evaluate its performance in activating the proliferation and organizing of cells, we have demonstrated specific behaviors of the cultured periodontal ligament cells on the self-organized honeycomb structures in vitro. Fibroblast-like cells derived from the periodontal ligament of extracted human molar teeth were cultivated on three types of honeycomb films with 5-, 10-, and 15-μm pore sizes for 4 h to 42 d. Morphological observation of the cultured tissues at 4-72 h revealed that the pseudopodiums of cell bodies were attached to the pillars in the honeycomb structure. A certain number of cells shifted their cell bodies into the honeycomb structural lumen through the oscula of 10- and 15-μm pores. After 28 and 42 d, the cells were observed to have formed multiple layers; further, each cell had penetrated through the 10- and 15-μm pores in the honeycomb film. The morphological examination of the honeycomb film along with the pillar structures revealed that the scaffold was clusteringly arrayed with interconnected structures, remarkably enhanced proliferation, and extension of the cultured cells. We consider that the film can be applied in periodontal therapy for use as a scaffold for periodontal tissue regeneration..
304. Hiroshi Ishihata, Masaru Tanaka, Nagayoshi Iwama, Masahiro Ara, Mitsuru Shimonishi, Masaru Nagamine, Noriaki Murakami, Sousuke Kanaya, Eiji Nemoto, Hidetoshi Shimauchi, Masatsugu Shimomura, Proliferation of periodontal ligament cells on biodegradable honeycomb film scaffold with unified micropore organization, Journal of Biomechanical Science and Engineering, 10.1299/jbse.5.252, 5, 3, 252-261, 2010.07, Tissue-engineered grafts using a scaffold can be used in treating periodontal disease; however, previous scaffolds for the cultivations of the periodontal ligament cells have been structurally incompatible with the morphological requirements of human periodontal tissue. Here, we describe a self-organized honeycomb-patterned film (honeycomb film) that acted as an appropriate scaffold for periodontal tissue regeneration. The honeycomb films were prepared from biodegradable poly(ε-caprolactone) with highly regular three-dimensional micropatterned surface topography by casting a polymer solution of water-immiscible solvent under humid conditions. To evaluate its performance in activating the proliferation and organizing of cells, we have demonstrated specific behaviors of the cultured periodontal ligament cells on the self-organized honeycomb structures in vitro. Fibroblast-like cells derived from the periodontal ligament of extracted human molar teeth were cultivated on three types of honeycomb films with 5-, 10-, and 15-μm pore sizes for 4 h to 42 d. Morphological observation of the cultured tissues at 4-72 h revealed that the pseudopodiums of cell bodies were attached to the pillars in the honeycomb structure. A certain number of cells shifted their cell bodies into the honeycomb structural lumen through the oscula of 10- and 15-μm pores. After 28 and 42 d, the cells were observed to have formed multiple layers; further, each cell had penetrated through the 10- and 15-μm pores in the honeycomb film. The morphological examination of the honeycomb film along with the pillar structures revealed that the scaffold was clusteringly arrayed with interconnected structures, remarkably enhanced proliferation, and extension of the cultured cells. We consider that the film can be applied in periodontal therapy for use as a scaffold for periodontal tissue regeneration..
305. T. Hatakeyama, M. Tanaka, H. Hatakeyama, Studies on bound water restrained by poly(2-methacryloyloxyethyl phosphorylcholine)
Comparison with polysaccharide-water systems, Acta Biomaterialia, 10.1016/j.actbio.2009.12.018, 6, 6, 2077-2082, 2010.06, The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC-water systems with a water content (Wc = mass of water/mass of dry sample, gg1) in the range 0-2.0 was measured in the temperature range-150 to 50 °C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a Wc in the range 0.5-0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was ∼0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC..
306. T. Hatakeyama, M. Tanaka, H. Hatakeyama, Studies on bound water restrained by poly(2-methacryloyloxyethyl phosphorylcholine): Comparison with polysaccharide-water systems, ACTA BIOMATERIALIA, 10.1016/j.actbio.2009.12.018, 6, 6, 2077-2082, 2010.06, The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC-water systems with a water content (W-c = mass of water/mass of dry sample, g g(-1)) in the range 0-2.0 was measured in the temperature range -150 to 50 degrees C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a W-c in the range 0.5-0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was similar to 0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC. (C) 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc..
307. T. Hatakeyama, Masaru Tanaka, H. Hatakeyama, Studies on bound water restrained by poly(2-methacryloyloxyethyl phosphorylcholine)
Comparison with polysaccharide-water systems, Acta Biomaterialia, 10.1016/j.actbio.2009.12.018, 6, 6, 2077-2082, 2010.01, The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC-water systems with a water content (Wc = mass of water/mass of dry sample, gg1) in the range 0-2.0 was measured in the temperature range-150 to 50 °C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a Wc in the range 0.5-0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was ∼0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC..
308. T. Hatakeyama, Masaru Tanaka, H. Hatakeyama, Studies on bound water restrained by poly(2-methacryloyloxyethyl phosphorylcholine)
Comparison with polysaccharide-water systems, Acta Biomaterialia, 10.1016/j.actbio.2009.12.018, 6, 6, 2077-2082, 2010.01, The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC-water systems with a water content (Wc = mass of water/mass of dry sample, gg1) in the range 0-2.0 was measured in the temperature range-150 to 50 °C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a Wc in the range 0.5-0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was ∼0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC..
309. Masaru Tanaka, Hirokazu Sato, Yugo Sasaya, Suguru Horinouchi, Jun Ichi Hotta, Yasutaka Matsuo, Kuniharu Ijiro, Keiji Sasaki, Masatsugu Shimomura, Fabrication of novel biocompatible surfaces by two-photon absorption technique using femtosecond laser, Molecular Crystals and Liquid Crystals, 10.1080/15421400902950121, 505, 1, 457-468, 2009.12, This study describes the preparation of biocompatible patterned surfaces by a two-photon absorption technique. We have synthesized poly(2-methoxyethyl acrylate) copolymers, which exhibit biocompatibility and photocrosslinking moiety. Fabrication resolution can be controlled in the sub-micrometer range by changing the laser power, photoinitiator concentration, and scanning speed. The patterned surfaces showed excellent human platelet compatibility. Biocompatible patterned surfaces can be used in various medical devices, implants, biosensor chips, and tissue engineering scaffolds..
310. Masaru Tanaka, Hirokazu Sato, Yugo Sasaya, Suguru Horinouchi, Jun Ichi Hotta, Yasutaka Matsuo, Kuniharu Ijiro, Keiji Sasaki, Masatsugu Shimomura, Fabrication of novel biocompatible surfaces by two-photon absorption technique using femtosecond laser, Molecular Crystals and Liquid Crystals, 10.1080/15421400902950121, 505, 1, 457-468, 2009.12, This study describes the preparation of biocompatible patterned surfaces by a two-photon absorption technique. We have synthesized poly(2-methoxyethyl acrylate) copolymers, which exhibit biocompatibility and photocrosslinking moiety. Fabrication resolution can be controlled in the sub-micrometer range by changing the laser power, photoinitiator concentration, and scanning speed. The patterned surfaces showed excellent human platelet compatibility. Biocompatible patterned surfaces can be used in various medical devices, implants, biosensor chips, and tissue engineering scaffolds..
311. Yuko Miwa, Hiroyuki Ishida, Hazime Saitô, Masaru Tanaka, Akira Mochizuki, Network structures and dynamics of dry and swollen poly(acrylate)s. Characterization of high- and low-frequency motions as revealed by suppressed or recovered intensities (SRI) analysis of 13C NMR, Polymer, 10.1016/j.polymer.2009.10.037, 50, 25, 6091-6099, 2009.11, We recorded temperature-dependent high-resolution 13C NMR spectra of dry and swollen poly(acrylate)s [poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(tetrahydrofurfuryl acrylate) (PTHFA)] by dipolar decoupled-magic angle spinning (DD-MAS) and cross-polarization-magic angle spinning (CP-MAS) methods, to gain insight into their network structures and dynamics. Suppressed or recovered intensities (SRI) analysis of 13C CP-MAS and DD-MAS NMR was successfully utilized, to reveal portions of dry and swollen polymers which undergo fast and slow motions with fluctuation frequencies in the order of 108 Hz and 104-105 Hz, respectively. Fast isotropic motions with frequency higher than 108 Hz at ambient temperature were located to the portions in which 13C CP-MAS NMR signals of swollen PMEA were selectively suppressed. In contrast, low-frequency motion was identified to the portions in which 13C DD-MAS (and CP-MAS) signals are most suppressed at the characteristic suppression temperature(s) Ts. Network of PMEA gels (containing 7 wt% of water) turns out to be formed by partial association of backbones only, as manifested from their Ts gradient at lowered temperature, whereas networks of PHEMA (containing 40 wt% of water) and PTHFA (9 wt% of water) gels are tightly formed through mutual inter-chain associations of both backbones and side-chains, as viewed from the raised Ts values for both near at ambient temperature. It is also interesting to note that flexibility of gel network (PMEA > PTHFA > PHEMA) characterized by the suppression temperature Ts (PMEA < PTHFA < PHEMA) is well related with a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system..
312. Yuko Miwa, Hiroyuki Ishida, Hazime Saitô, Masaru Tanaka, Akira Mochizuki, Network structures and dynamics of dry and swollen poly(acrylate)s. Characterization of high- and low-frequency motions as revealed by suppressed or recovered intensities (SRI) analysis of 13C NMR, Polymer, 10.1016/j.polymer.2009.10.037, 50, 25, 6091-6099, 2009.11, We recorded temperature-dependent high-resolution 13C NMR spectra of dry and swollen poly(acrylate)s [poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(tetrahydrofurfuryl acrylate) (PTHFA)] by dipolar decoupled-magic angle spinning (DD-MAS) and cross-polarization-magic angle spinning (CP-MAS) methods, to gain insight into their network structures and dynamics. Suppressed or recovered intensities (SRI) analysis of 13C CP-MAS and DD-MAS NMR was successfully utilized, to reveal portions of dry and swollen polymers which undergo fast and slow motions with fluctuation frequencies in the order of 108 Hz and 104-105 Hz, respectively. Fast isotropic motions with frequency higher than 108 Hz at ambient temperature were located to the portions in which 13C CP-MAS NMR signals of swollen PMEA were selectively suppressed. In contrast, low-frequency motion was identified to the portions in which 13C DD-MAS (and CP-MAS) signals are most suppressed at the characteristic suppression temperature(s) Ts. Network of PMEA gels (containing 7 wt% of water) turns out to be formed by partial association of backbones only, as manifested from their Ts gradient at lowered temperature, whereas networks of PHEMA (containing 40 wt% of water) and PTHFA (9 wt% of water) gels are tightly formed through mutual inter-chain associations of both backbones and side-chains, as viewed from the raised Ts values for both near at ambient temperature. It is also interesting to note that flexibility of gel network (PMEA > PTHFA > PHEMA) characterized by the suppression temperature Ts (PMEA < PTHFA < PHEMA) is well related with a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system..
313. Yuko Miwa, Hiroyuki Ishida, Hazime Saitô, Masaru Tanaka, Akira Mochizuki, Network structures and dynamics of dry and swollen poly(acrylate)s. Characterization of high- and low-frequency motions as revealed by suppressed or recovered intensities (SRI) analysis of 13C NMR, polymer, 10.1016/j.polymer.2009.10.037, 50, 25, 6091-6099, 2009.11, We recorded temperature-dependent high-resolution 13C NMR spectra of dry and swollen poly(acrylate)s [poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(tetrahydrofurfuryl acrylate) (PTHFA)] by dipolar decoupled-magic angle spinning (DD-MAS) and cross-polarization-magic angle spinning (CP-MAS) methods, to gain insight into their network structures and dynamics. Suppressed or recovered intensities (SRI) analysis of 13C CP-MAS and DD-MAS NMR was successfully utilized, to reveal portions of dry and swollen polymers which undergo fast and slow motions with fluctuation frequencies in the order of 108 Hz and 104-105 Hz, respectively. Fast isotropic motions with frequency higher than 108 Hz at ambient temperature were located to the portions in which 13C CP-MAS NMR signals of swollen PMEA were selectively suppressed. In contrast, low-frequency motion was identified to the portions in which 13C DD-MAS (and CP-MAS) signals are most suppressed at the characteristic suppression temperature(s) Ts. Network of PMEA gels (containing 7 wt% of water) turns out to be formed by partial association of backbones only, as manifested from their Ts gradient at lowered temperature, whereas networks of PHEMA (containing 40 wt% of water) and PTHFA (9 wt% of water) gels are tightly formed through mutual inter-chain associations of both backbones and side-chains, as viewed from the raised Ts values for both near at ambient temperature. It is also interesting to note that flexibility of gel network (PMEA > PTHFA > PHEMA) characterized by the suppression temperature Ts (PMEA < PTHFA < PHEMA) is well related with a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system..
314. Yuko Miwa, Hiroyuki Ishida, Hazime Saito, Masaru Tanaka, Akira Mochizuki, Network structures and dynamics of dry and swollen poly(acrylate)s. Characterization of high- and low-frequency motions as revealed by suppressed or recovered intensities (SRI) analysis of C-13 NMR, POLYMER, 10.1016/j.polymer.2009.10.037, 50, 25, 6091-6099, 2009.11, We recorded temperature-dependent high-resolution C-13 NMR spectra of dry and swollen poly(acrylate)s [poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(tetrahydrofurfuryl acrylate) (PTHFA)] by dipolar decoupled-magic angle spinning (DD-MAS) and cross-polarization-magic angle spinning (CP-MAS) methods, to gain insight into their network structures and dynamics. Suppressed or recovered intensities (SRI) analysis of C-13 CP-MAS and DD-MAS NMR was successfully utilized, to reveal portions of dry and swollen polymers which undergo fast and slow motions with fluctuation frequencies in the order of 10(8) Hz and 10(4)-10(5) Hz, respectively. Fast isotropic motions with frequency higher than 10(8) Hz at ambient temperature were located to the portions in which C-13 CP-MAS NMR signals of swollen PMEA were selectively suppressed. In contrast, low-frequency motion was identified to the portions in which C-13 DD-MAS (and CP-MAS) signals are most suppressed at the characteristic suppression temperature(s) T-s. Network of PMEA gels (containing 7 wt% of water) turns out to be formed by partial association of backbones only, as manifested from their T-s gradient at lowered temperature, whereas networks of PHEMA (containing 40 wt% of water) and PTHFA (9 wt% of water) gels are tightly formed through mutual inter-chain associations of both backbones and side-chains, as viewed from the raised T-s values for both near at ambient temperature. It is also interesting to note that flexibility of gel network (PMEA > PTHFA > PHEMA) characterized by the suppression temperature T-s (PMEA < PTHFA < PHEMA) is well related with a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system. (C) 2009 Elsevier Ltd. All rights reserved..
315. Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell fate using self-organized honeycomb-patterned films, European Cells and Materials, 18, SUPPL. 2, 2, 2009.07.
316. Nagayoshi Iwama, Masaru Tanaka, Hiroshi Ishihata, Masahiro Ara, Mitsuru Shimonishi, Masaru Nagamine, Noriaki Murakami, Sousuke Kanaya, Eiji Nemoto, Hidetoshi Shimauchi, Masatsugu Shimomura, Control of human periodontal ligament cells proliferation on honeycomb-patterned films for regenerative periodontal therapy, European Cells and Materials, 18, SUPPL. 2, 67, 2009.07.
317. Masaru Tanaka, Akinori Tsuruma, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell adhesion and functions using self-organized honey Comb-patterned polymer films, Biodevices, 390-393, 2009.07, The design of nano-and microstructures based on self-organization is a key area of research in the search for new biomaterials and biodevices,and such structures have a variety of potential applications in tissue engineering scaffolds and medical implants.3D scaffolds of appropriate pore size and porosities and with interconnected pores are required to facilitate cell adhesion, proliferation,differentiation,and eventual tissue regeneration in a natural manner.We have reported the honeycomb-patterned polymer film with highly regular pores that is formed by self-organization.The honeycomb films exerted a strong influence on cell morphology, proliferation,cytoskeleton, focal adhesion,and ECM production profiles.Our studies demonstrated that the neural stem / progenitor cells morphology,proliferation,and differentiation are controlled by the pore size of the honeycomb film.It is expected that the honeycomb films will have great potentials as biomaterials for tissue regeneration in a growth factor free proliferation process of stem cells..
318. Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell fate using self-organized honeycomb-patterned films, European Cells and Materials, 18, SUPPL. 2, 2, 2009.07.
319. Nagayoshi Iwama, Masaru Tanaka, Hiroshi Ishihata, Masahiro Ara, Mitsuru Shimonishi, Masaru Nagamine, Noriaki Murakami, Sousuke Kanaya, Eiji Nemoto, Hidetoshi Shimauchi, Masatsugu Shimomura, Control of human periodontal ligament cells proliferation on honeycomb-patterned films for regenerative periodontal therapy, European Cells and Materials, 18, SUPPL. 2, 67, 2009.07.
320. Masaru Tanaka, Akinori Tsuruma, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell adhesion and functions using self-organized honey Comb-patterned polymer films, 2nd International Conference on Biomedical Electronics and Devices, BIODEVICES 2009 BIODEVICES 2009 - Proceedings of the 2nd International Conference on Biomedical Electronics and Devices, 390-393, 2009.07, The design of nano-and microstructures based on self-organization is a key area of research in the search for new biomaterials and biodevices,and such structures have a variety of potential applications in tissue engineering scaffolds and medical implants.3D scaffolds of appropriate pore size and porosities and with interconnected pores are required to facilitate cell adhesion, proliferation,differentiation,and eventual tissue regeneration in a natural manner.We have reported the honeycomb-patterned polymer film with highly regular pores that is formed by self-organization.The honeycomb films exerted a strong influence on cell morphology, proliferation,cytoskeleton, focal adhesion,and ECM production profiles.Our studies demonstrated that the neural stem / progenitor cells morphology,proliferation,and differentiation are controlled by the pore size of the honeycomb film.It is expected that the honeycomb films will have great potentials as biomaterials for tissue regeneration in a growth factor free proliferation process of stem cells..
321. Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell fate using self-organized honeycomb-patterned films, European Cells and Materials, 18, SUPPL. 2, 2, 2009.07.
322. Nagayoshi Iwama, Masaru Tanaka, Hiroshi Ishihata, Masahiro Ara, Mitsuru Shimonishi, Masaru Nagamine, Noriaki Murakami, Sousuke Kanaya, Eiji Nemoto, Hidetoshi Shimauchi, Masatsugu Shimomura, Control of human periodontal ligament cells proliferation on honeycomb-patterned films for regenerative periodontal therapy, European Cells and Materials, 18, SUPPL. 2, 2009.07.
323. Masaru Tanaka, Masafumi Takebayashi, Masatsugu Shimomura, Fabrication of ordered arrays of biodegradable polymer pincushions using self-organized honeycomb-patterned films, Macromolecular Symposia, 10.1002/masy.200950527, 279, 1, 175-182, 2009.05, Nano- and micropatterned structures of tissue engineering scaffolds made of biodegradable and biocompatible polymers profoundly influence cell behavior. The present study describes a technically simple and inexpensive method to rapidly fabricate hexagonal arrays of biodegradable polymer pillars (pincushions). As precursors to these polymer pincushion arrays, highly regular porous biodegradable polymer films (self-organized honeycomb-patterned films, called honeycomb films) were prepared on a glass substrate using a simple casting technique. Scanning electron microscope observations revealed that the honeycomb film was composed of a top and bottom layer. This double-layered structure is attributable to the self-organization of hexagonally packed arrays of water droplets that form the template. When we peeled off the top layer of the honeycomb film under ambient conditions using adhesive tape, we obtained arrays of polymer pincushions on both side of the glass substrate and on the adhesive tape. Each air hole is surrounded by six pincushions, each with a diameter of 0.1-1 mm. We also studied factors that determine the morphology of the pincushions, such as the thermal and mechanical properties of the polymers used. It was shown that the heights, widths, and distances of separation between the pincushions could be controlled by the choice of polymer and the pore structure of the original honeycomb film. Such well-ordered, biologically inspired pincushion structures could find application in biomedical, photonic, and electronic materials..
324. Masaru Tanaka, Masafumi Takebayashi, Masatsugu Shimomura, Fabrication of ordered arrays of biodegradable polymer pincushions using self-organized honeycomb-patterned films, Macromolecular Symposia, 10.1002/masy.200950527, 279, 1, 175-182, 2009.05, Nano- and micropatterned structures of tissue engineering scaffolds made of biodegradable and biocompatible polymers profoundly influence cell behavior. The present study describes a technically simple and inexpensive method to rapidly fabricate hexagonal arrays of biodegradable polymer pillars (pincushions). As precursors to these polymer pincushion arrays, highly regular porous biodegradable polymer films (self-organized honeycomb-patterned films, called honeycomb films) were prepared on a glass substrate using a simple casting technique. Scanning electron microscope observations revealed that the honeycomb film was composed of a top and bottom layer. This double-layered structure is attributable to the self-organization of hexagonally packed arrays of water droplets that form the template. When we peeled off the top layer of the honeycomb film under ambient conditions using adhesive tape, we obtained arrays of polymer pincushions on both side of the glass substrate and on the adhesive tape. Each air hole is surrounded by six pincushions, each with a diameter of 0.1-1 mm. We also studied factors that determine the morphology of the pincushions, such as the thermal and mechanical properties of the polymers used. It was shown that the heights, widths, and distances of separation between the pincushions could be controlled by the choice of polymer and the pore structure of the original honeycomb film. Such well-ordered, biologically inspired pincushion structures could find application in biomedical, photonic, and electronic materials..
325. Masaru Tanaka, Masafumi Takebayashi, Masatsugu Shimomura, Fabrication of ordered arrays of biodegradable polymer pincushions using self-organized honeycomb-patterned films, Macromolecular Symposia, 10.1002/masy.200950527, 279, 1, 175-182, 2009.05, Nano- and micropatterned structures of tissue engineering scaffolds made of biodegradable and biocompatible polymers profoundly influence cell behavior. The present study describes a technically simple and inexpensive method to rapidly fabricate hexagonal arrays of biodegradable polymer pillars (pincushions). As precursors to these polymer pincushion arrays, highly regular porous biodegradable polymer films (self-organized honeycomb-patterned films, called honeycomb films) were prepared on a glass substrate using a simple casting technique. Scanning electron microscope observations revealed that the honeycomb film was composed of a top and bottom layer. This double-layered structure is attributable to the self-organization of hexagonally packed arrays of water droplets that form the template. When we peeled off the top layer of the honeycomb film under ambient conditions using adhesive tape, we obtained arrays of polymer pincushions on both side of the glass substrate and on the adhesive tape. Each air hole is surrounded by six pincushions, each with a diameter of 0.1-1 mm. We also studied factors that determine the morphology of the pincushions, such as the thermal and mechanical properties of the polymers used. It was shown that the heights, widths, and distances of separation between the pincushions could be controlled by the choice of polymer and the pore structure of the original honeycomb film. Such well-ordered, biologically inspired pincushion structures could find application in biomedical, photonic, and electronic materials..
326. Akira Mochizuki, Tatsuko Hatakeyama, Yuka Tomono, Masaru Tanaka, Water structure and blood compatibility of poly(tetrahydrofurfuryl acrylate), Journal of Biomaterials Science, Polymer Edition, 10.1163/156856209X426411, 20, 5-6, 591-603, 2009.03, We previously reported that poly(2-methoxyethyl acrylate) (PMEA), which has excellent blood compatibility, contains a large amount of freezing bound water. In order to confirm the role of freezing bound water in determining blood compatibility, poly(tetrahydrofurfuryl acrylate) (PTHFA) was newly synthesized and the thermal properties of water in PTHFA were investigated by differential scanning calorimetry (DSC), as freezing bound water was observed as cold crystallization in DSC heating curves. In addition, the blood compatibility of PTHFA, including activations of platelets, the coagulation system and the complement system, was investigated. The temperature of cold crystallization of water in PTHFA was higher than that of water in PMEA; moreover, the amount of freezing bound water in PTHFA was smaller than that in PMEA. The effect of freezing bound water on blood compatibility was investigated by comparing PTHFA, PMEA, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-methoxyethyl methacrylate) (PMEMA). The latter two samples showed no cold crystallization. Activations of platelets, the coagulation system and the complement system were enhanced in the following order: PMEA < PHEMA < PTHFA < PMEMA, PMEA < PMEMA < PTHFA < PHEMA and PMEA < PTHFA < PMEMA < PHEMA, respectively. The above results were reasonably explained by the amount and/or the stability of freezing bound water..
327. Akira Mochizuki, Tatsuko Hatakeyama, Yuka Tomono, Masaru Tanaka, Water structure and blood compatibility of poly(tetrahydrofurfuryl acrylate), Journal of Biomaterials Science, Polymer Edition, 10.1163/156856209X426411, 20, 5-6, 591-603, 2009.03, We previously reported that poly(2-methoxyethyl acrylate) (PMEA), which has excellent blood compatibility, contains a large amount of freezing bound water. In order to confirm the role of freezing bound water in determining blood compatibility, poly(tetrahydrofurfuryl acrylate) (PTHFA) was newly synthesized and the thermal properties of water in PTHFA were investigated by differential scanning calorimetry (DSC), as freezing bound water was observed as cold crystallization in DSC heating curves. In addition, the blood compatibility of PTHFA, including activations of platelets, the coagulation system and the complement system, was investigated. The temperature of cold crystallization of water in PTHFA was higher than that of water in PMEA; moreover, the amount of freezing bound water in PTHFA was smaller than that in PMEA. The effect of freezing bound water on blood compatibility was investigated by comparing PTHFA, PMEA, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-methoxyethyl methacrylate) (PMEMA). The latter two samples showed no cold crystallization. Activations of platelets, the coagulation system and the complement system were enhanced in the following order: PMEA < PHEMA < PTHFA < PMEMA, PMEA < PMEMA < PTHFA < PHEMA and PMEA < PTHFA < PMEMA < PHEMA, respectively. The above results were reasonably explained by the amount and/or the stability of freezing bound water..
328. Akira Mochizuki, Tatsuko Hatakeyama, Yuka Tomono, Masaru Tanaka, Water structure and blood compatibility of poly(tetrahydrofurfuryl acrylate), Journal of Biomaterials Science, Polymer Edition, 10.1163/156856209X426411, 20, 5-6, 591-603, 2009.03, We previously reported that poly(2-methoxyethyl acrylate) (PMEA), which has excellent blood compatibility, contains a large amount of freezing bound water. In order to confirm the role of freezing bound water in determining blood compatibility, poly(tetrahydrofurfuryl acrylate) (PTHFA) was newly synthesized and the thermal properties of water in PTHFA were investigated by differential scanning calorimetry (DSC), as freezing bound water was observed as cold crystallization in DSC heating curves. In addition, the blood compatibility of PTHFA, including activations of platelets, the coagulation system and the complement system, was investigated. The temperature of cold crystallization of water in PTHFA was higher than that of water in PMEA; moreover, the amount of freezing bound water in PTHFA was smaller than that in PMEA. The effect of freezing bound water on blood compatibility was investigated by comparing PTHFA, PMEA, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-methoxyethyl methacrylate) (PMEMA). The latter two samples showed no cold crystallization. Activations of platelets, the coagulation system and the complement system were enhanced in the following order: PMEA < PHEMA < PTHFA < PMEMA, PMEA < PMEMA < PTHFA < PHEMA and PMEA < PTHFA < PMEMA < PHEMA, respectively. The above results were reasonably explained by the amount and/or the stability of freezing bound water..
329. Sulumu Tada, Chika Inaba, Kazuya Mizukami, Shigeto Fujishita, Makoto Geminei-Ide, Hiromi Kitano, Akira Mochizuki, Masaru Tanaka, Takayuki Matsunaga, Anti-biofouling properties of polymers with a carboxybetaine moiety, Macromolecular Bioscience, 10.1002/mabi.200800150, 9, 1, 63-70, 2009.01, The resistance of random copolymers of BMA and CMB against biofouling was evaluated. The amount of proteins adsorbed onto the CMB copolymers was smaller than that onto other polymers (non-ionic polymers and copolymers of ordinary ionic monomers and BMA) and decreased with an increase in the content of CMB residues. Furthermore, there was a dramatic decrease in the number of cells (platelets and fibroblasts) that adhered to the CMB copolymers compared with that to other polymers. In contrast with this, CMB copolymers were slightly perturbative to both complement and coagulation systems. However, the overall results suggest that zwitterionic moieties are effective for making polymer materials biocompatible due to their excellent anti-biofouling property. A graph is presented..
330. Akira Kishi, Masaru Tanaka, Akira Mochizuki, Comparative study on water structures in PolyHEMA and PolyMEA by XRD-DSC simultaneous measurement, Journal of Applied Polymer Science, 10.1002/app.29127, 111, 1, 476-481, 2009.01, We have found that poly(2-methoxyethylacrylate) (polyMEA) has excellent blood compatibility and proposed that the property is due to freezing bound water in the polymer. This water is defined as that which cold-crystallizes at around -45°C in the heating process of differential scanning calorimetry (DSC). In addition, we have already reported that the water in polyMEA is classified into three types, nonfreezing, freezing bound, and free waters, whereas the water in other polymers is just classified into two types: free and nonfreezing waters. (J Biomed Mater Res 68A, 2004, 684) However, the phenomenon observed by DSC is the enthalpy change and is not a direct evidence for crystallization. To confirm coldcrystallization, a comparative investigation of the thermal and crystallographical properties of water in hydrated polyMEA and poly(2-hydroxyethylmethacrylate) (polyHEMA) as a control was carried out using simultaneous measurements by X-ray diffractometer (XRD) and DSC. In addition, the effect of the water content in the polymers on the properties was studied. As for polyMEA, the finding that XRD crystalline peaks appearing in the heating process were assigned to hexagonal ice indicated cold-crystallization. On the other hand, in the case of polyHEMA, the crystal due to ice was formed only in the cooling process, and during the heating process, the growth of crystal ice was not observed..
331. Mei Chen Yong, Jian Ping Gong, Masaru Tanaka, Kazunori Yasuda, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Tuning of cell proliferation on tough gels by critical charge effect, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.31869, 88, 1, 74-83, 2009.01, Tough triple network (TN) hydrogels that facilitate cell spreading and proliferation and, at the same time, preserve high mechanical strength are synthesized by the introduction of a proper component of negatively charged moiety, poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS), on which cells proliferate, with neutral moiety, poly(N,N-dimethylacrylamide) (DMAAm), on which cells do not proliferate, as the third network component, to PNaAMPS/PDMAAm double network (DN) gels. For synthesizing the tough TN gels to support cell viability, the effect of charge density on the behaviors of three kinds of cells, bovine fetal aorta endothelial cells (BFAECs), human umbilical endothelial cells (HUVECs), and rabbit synovial tissue-derived fibroblast cells (RSTFCs) were systematically investigated on poly(NaAMPS-co-DMAAm) gels with different charge density. The charge density of the gels was tuned by changing the molar fraction (F) of negatively charged monomer in the copolymer hydrogels. Critical F, which corresponds to a critical value of the zeta potential (ζ), is observed for cell spreading and proliferation. The critical F for BFAECs and HUVECs proliferate to confluent is F = 0.4 (ζ = -20 mV), whereas the critical F for RSTFCs shifts to F = 0.7 (ζ = -28.5 mV). The effect of gel charge density on cell behavior is correlated well with the total adsorbed proteins and fibronectin. By applying these results, cell proliferation is successfully realized on the tough TN hydrogels without surface modification with any cell adhesive proteins or peptides. The results will substantially promote the application of tough hydrogels as soft and wet tissues..
332. Sulumu Tada, Chika Inaba, Kazuya Mizukami, Shigeto Fujishita, Makoto Geminei-Ide, Hiromi Kitano, Akira Mochizuki, Masaru Tanaka, Takayuki Matsunaga, Anti-biofouling properties of polymers with a carboxybetaine moiety, Macromolecular Bioscience, 10.1002/mabi.200800150, 9, 1, 63-70, 2009.01, The resistance of random copolymers of BMA and CMB against biofouling was evaluated. The amount of proteins adsorbed onto the CMB copolymers was smaller than that onto other polymers (non-ionic polymers and copolymers of ordinary ionic monomers and BMA) and decreased with an increase in the content of CMB residues. Furthermore, there was a dramatic decrease in the number of cells (platelets and fibroblasts) that adhered to the CMB copolymers compared with that to other polymers. In contrast with this, CMB copolymers were slightly perturbative to both complement and coagulation systems. However, the overall results suggest that zwitterionic moieties are effective for making polymer materials biocompatible due to their excellent anti-biofouling property. A graph is presented..
333. Akira Kishi, Masaru Tanaka, Akira Mochizuki, Comparative study on water structures in PolyHEMA and PolyMEA by XRD-DSC simultaneous measurement, Journal of Applied Polymer Science, 10.1002/app.29127, 111, 1, 476-481, 2009.01, We have found that poly(2-methoxyethylacrylate) (polyMEA) has excellent blood compatibility and proposed that the property is due to freezing bound water in the polymer. This water is defined as that which cold-crystallizes at around -45°C in the heating process of differential scanning calorimetry (DSC). In addition, we have already reported that the water in polyMEA is classified into three types, nonfreezing, freezing bound, and free waters, whereas the water in other polymers is just classified into two types: free and nonfreezing waters. (J Biomed Mater Res 68A, 2004, 684) However, the phenomenon observed by DSC is the enthalpy change and is not a direct evidence for crystallization. To confirm coldcrystallization, a comparative investigation of the thermal and crystallographical properties of water in hydrated polyMEA and poly(2-hydroxyethylmethacrylate) (polyHEMA) as a control was carried out using simultaneous measurements by X-ray diffractometer (XRD) and DSC. In addition, the effect of the water content in the polymers on the properties was studied. As for polyMEA, the finding that XRD crystalline peaks appearing in the heating process were assigned to hexagonal ice indicated cold-crystallization. On the other hand, in the case of polyHEMA, the crystal due to ice was formed only in the cooling process, and during the heating process, the growth of crystal ice was not observed..
334. Mei Chen Yong, Jian Ping Gong, Masaru Tanaka, Kazunori Yasuda, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Tuning of cell proliferation on tough gels by critical charge effect, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.31869, 88, 1, 74-83, 2009.01, Tough triple network (TN) hydrogels that facilitate cell spreading and proliferation and, at the same time, preserve high mechanical strength are synthesized by the introduction of a proper component of negatively charged moiety, poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS), on which cells proliferate, with neutral moiety, poly(N,N-dimethylacrylamide) (DMAAm), on which cells do not proliferate, as the third network component, to PNaAMPS/PDMAAm double network (DN) gels. For synthesizing the tough TN gels to support cell viability, the effect of charge density on the behaviors of three kinds of cells, bovine fetal aorta endothelial cells (BFAECs), human umbilical endothelial cells (HUVECs), and rabbit synovial tissue-derived fibroblast cells (RSTFCs) were systematically investigated on poly(NaAMPS-co-DMAAm) gels with different charge density. The charge density of the gels was tuned by changing the molar fraction (F) of negatively charged monomer in the copolymer hydrogels. Critical F, which corresponds to a critical value of the zeta potential (ζ), is observed for cell spreading and proliferation. The critical F for BFAECs and HUVECs proliferate to confluent is F = 0.4 (ζ = -20 mV), whereas the critical F for RSTFCs shifts to F = 0.7 (ζ = -28.5 mV). The effect of gel charge density on cell behavior is correlated well with the total adsorbed proteins and fibronectin. By applying these results, cell proliferation is successfully realized on the tough TN hydrogels without surface modification with any cell adhesive proteins or peptides. The results will substantially promote the application of tough hydrogels as soft and wet tissues..
335. Sulumu Tada, Chika Inaba, Kazuya Mizukami, Shigeto Fujishita, Makoto Geminei-Ide, Hiromi Kitano, Akira Mochizuki, Masaru Tanaka, Takayuki Matsunaga, Anti-biofouling properties of polymers with a carboxybetaine moiety, Macromolecular Bioscience, 10.1002/mabi.200800150, 9, 1, 63-70, 2009.01, The resistance of random copolymers of BMA and CMB against biofouling was evaluated. The amount of proteins adsorbed onto the CMB copolymers was smaller than that onto other polymers (non-ionic polymers and copolymers of ordinary ionic monomers and BMA) and decreased with an increase in the content of CMB residues. Furthermore, there was a dramatic decrease in the number of cells (platelets and fibroblasts) that adhered to the CMB copolymers compared with that to other polymers. In contrast with this, CMB copolymers were slightly perturbative to both complement and coagulation systems. However, the overall results suggest that zwitterionic moieties are effective for making polymer materials biocompatible due to their excellent anti-biofouling property. A graph is presented..
336. Akira Kishi, Masaru Tanaka, Akira Mochizuki, Comparative study on water structures in PolyHEMA and PolyMEA by XRD-DSC simultaneous measurement, Journal of Applied Polymer Science, 10.1002/app.29127, 111, 1, 476-481, 2009.01, We have found that poly(2-methoxyethylacrylate) (polyMEA) has excellent blood compatibility and proposed that the property is due to freezing bound water in the polymer. This water is defined as that which cold-crystallizes at around -45°C in the heating process of differential scanning calorimetry (DSC). In addition, we have already reported that the water in polyMEA is classified into three types, nonfreezing, freezing bound, and free waters, whereas the water in other polymers is just classified into two types: free and nonfreezing waters. (J Biomed Mater Res 68A, 2004, 684) However, the phenomenon observed by DSC is the enthalpy change and is not a direct evidence for crystallization. To confirm coldcrystallization, a comparative investigation of the thermal and crystallographical properties of water in hydrated polyMEA and poly(2-hydroxyethylmethacrylate) (polyHEMA) as a control was carried out using simultaneous measurements by X-ray diffractometer (XRD) and DSC. In addition, the effect of the water content in the polymers on the properties was studied. As for polyMEA, the finding that XRD crystalline peaks appearing in the heating process were assigned to hexagonal ice indicated cold-crystallization. On the other hand, in the case of polyHEMA, the crystal due to ice was formed only in the cooling process, and during the heating process, the growth of crystal ice was not observed..
337. Mei Chen Yong, Jian Ping Gong, Masaru Tanaka, Kazunori Yasuda, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Tuning of cell proliferation on tough gels by critical charge effect, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.31869, 88, 1, 74-83, 2009.01, Tough triple network (TN) hydrogels that facilitate cell spreading and proliferation and, at the same time, preserve high mechanical strength are synthesized by the introduction of a proper component of negatively charged moiety, poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS), on which cells proliferate, with neutral moiety, poly(N,N-dimethylacrylamide) (DMAAm), on which cells do not proliferate, as the third network component, to PNaAMPS/PDMAAm double network (DN) gels. For synthesizing the tough TN gels to support cell viability, the effect of charge density on the behaviors of three kinds of cells, bovine fetal aorta endothelial cells (BFAECs), human umbilical endothelial cells (HUVECs), and rabbit synovial tissue-derived fibroblast cells (RSTFCs) were systematically investigated on poly(NaAMPS-co-DMAAm) gels with different charge density. The charge density of the gels was tuned by changing the molar fraction (F) of negatively charged monomer in the copolymer hydrogels. Critical F, which corresponds to a critical value of the zeta potential (ζ), is observed for cell spreading and proliferation. The critical F for BFAECs and HUVECs proliferate to confluent is F = 0.4 (ζ = -20 mV), whereas the critical F for RSTFCs shifts to F = 0.7 (ζ = -28.5 mV). The effect of gel charge density on cell behavior is correlated well with the total adsorbed proteins and fibronectin. By applying these results, cell proliferation is successfully realized on the tough TN hydrogels without surface modification with any cell adhesive proteins or peptides. The results will substantially promote the application of tough hydrogels as soft and wet tissues..
338. Susumu Tada, Chika Inaba, Kazuya Mizukami, Shigeto Fujishita, Makoto Gemmei-Ide, Hiromi Kitano, Akira Mochizuki, Masaru Tanaka, Takayuki Matsunaga, Anti-Biofouling Properties of Polymers with a Carboxybetaine Moiety, MACROMOLECULAR BIOSCIENCE, 10.1002/mabi.200800150, 9, 1, 63-70, 2009.01, The resistance of random copolymers of BMA and CMB against biofouling was evaluated. The amount of proteins adsorbed onto the CMB copolymers was smaller than that onto other polymers (non-ionic polymers and copolymers of ordinary ionic monomers and BMA) and decreased with an increase in the content of CMB residues. Furthermore, there was a dramatic decrease in the number of cells (platelets and fibroblasts) that adhered to the CMB copolymers compared with that to other polymers. In contrast with this, CMB copolymers were slightly perturbative to both complement and coagulation systems. However, the overall results suggest that zwitterionic moieties are effective for making polymer materials biocompatible due to their excellent anti-biofouling property..
339. Masaru Tanaka, Akinori Tsuruma, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell adhesion and functions using self-organized honey Comb-patterned polymer films, 2nd International Conference on Biomedical Electronics and Devices, BIODEVICES 2009 BIODEVICES 2009 - Proceedings of the 2nd International Conference on Biomedical Electronics and Devices, 390-393, 2009, The design of nano-and microstructures based on self-organization is a key area of research in the search for new biomaterials and biodevices,and such structures have a variety of potential applications in tissue engineering scaffolds and medical implants.3D scaffolds of appropriate pore size and porosities and with interconnected pores are required to facilitate cell adhesion, proliferation,differentiation,and eventual tissue regeneration in a natural manner.We have reported the honeycomb-patterned polymer film with highly regular pores that is formed by self-organization.The honeycomb films exerted a strong influence on cell morphology, proliferation,cytoskeleton, focal adhesion,and ECM production profiles.Our studies demonstrated that the neural stem / progenitor cells morphology,proliferation,and differentiation are controlled by the pore size of the honeycomb film.It is expected that the honeycomb films will have great potentials as biomaterials for tissue regeneration in a growth factor free proliferation process of stem cells..
340. Masaru Tanaka, Hirokazu Sato, Yugo Sasaya, Suguru Horinouchi, Jun Ichi Hotta, Yasutaka Matsuo, Kuniharu Ijiro, Keiji Sasaki, Masatsugu Shimomura, Fabrication of novel biocompatible surfaces by two-photon absorption technique using femtosecond laser, Molecular Crystals and Liquid Crystals, 10.1080/15421400902950121, 505, 1, 219/[457]-230/[468], 2009, This study describes the preparation of biocompatible patterned surfaces by a two-photon absorption technique. We have synthesized poly(2-methoxyethyl acrylate) copolymers, which exhibit biocompatibility and photocrosslinking moiety. Fabrication resolution can be controlled in the sub-micrometer range by changing the laser power, photoinitiator concentration, and scanning speed. The patterned surfaces showed excellent human platelet compatibility. Biocompatible patterned surfaces can be used in various medical devices, implants, biosensor chips, and tissue engineering scaffolds..
341. Yukako Fukuhira, Masaya Ito, Hiroaki Kaneko, Yoshihiko Sumi, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Prevention of postoperative adhesions by a novel honeycomb-patterned poly(lactide) film in a rat experimental model, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.31026, 86, 2, 353-359, 2008.08, Intraperitoneal adhesion is a serious problem concerning abdominal surgery. This study evaluated the performance of a honeycomb-patterned poly(lactide) (HCPLA) film as a physical barrier for preventing postoperative adhesion. HCPLA films were prepared using dioleoylphosphatidylethanolamine (DOPE) or a copolymer of dodecylacrylamide and ω-carboxyhexylacrylamide (CAP) as a surfactant (HCPLA-DOPE and HCPLA-CAP, respectively). In an in vivo adhesion prevention experiment, male Sprague-Dawley rats underwent standard cecum abrasion before midline laparotomy. We placed 2 cm x 2 cm HCPLA and flat films on the gliding interfaces; untreated rats formed the control group. After 1 week, adhesion was scored from 0 to 4. No significant difference was observed in the scores among groups, but macroscopic differences in adhesion prevention were observed. The adhesive strength of HCPLA-DOPE (18.1 ± 1.2 g) to skinless chicken breast was significantly higher than that of the flat film (15.2 ± 0.8 g, p < 0.05). Further, the adhesion score after 1 week for the HCPLA-DOPE group (1.6 ± 0.2) was significantly lower than that for the control group (3.0 ±0.3, ñ< 0.05) but comparable to that for the Seprafilm™ group (1.4 ± 0.3). These results demonstrated the potential of HCPLA-DOPE as a physical barrier for preventing postoperative adhesion..
342. Yukako Fukuhira, Masaya Ito, Hiroaki Kaneko, Yoshihiko Sumi, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Prevention of postoperative adhesions by a novel honeycomb-patterned poly(lactide) film in a rat experimental model, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.31026, 86, 2, 353-359, 2008.08, Intraperitoneal adhesion is a serious problem concerning abdominal surgery. This study evaluated the performance of a honeycomb-patterned poly(lactide) (HCPLA) film as a physical barrier for preventing postoperative adhesion. HCPLA films were prepared using dioleoylphosphatidylethanolamine (DOPE) or a copolymer of dodecylacrylamide and ω-carboxyhexylacrylamide (CAP) as a surfactant (HCPLA-DOPE and HCPLA-CAP, respectively). In an in vivo adhesion prevention experiment, male Sprague-Dawley rats underwent standard cecum abrasion before midline laparotomy. We placed 2 cm x 2 cm HCPLA and flat films on the gliding interfaces; untreated rats formed the control group. After 1 week, adhesion was scored from 0 to 4. No significant difference was observed in the scores among groups, but macroscopic differences in adhesion prevention were observed. The adhesive strength of HCPLA-DOPE (18.1 ± 1.2 g) to skinless chicken breast was significantly higher than that of the flat film (15.2 ± 0.8 g, p < 0.05). Further, the adhesion score after 1 week for the HCPLA-DOPE group (1.6 ± 0.2) was significantly lower than that for the control group (3.0 ±0.3, ñ< 0.05) but comparable to that for the Seprafilm™ group (1.4 ± 0.3). These results demonstrated the potential of HCPLA-DOPE as a physical barrier for preventing postoperative adhesion..
343. Yukako Fukuhira, Masaya Ito, Hiroaki Kaneko, Yoshihiko Sumi, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Prevention of postoperative adhesions by a novel honeycomb-patterned poly(lactide) film in a rat experimental model, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.31026, 86, 2, 353-359, 2008.08, Intraperitoneal adhesion is a serious problem concerning abdominal surgery. This study evaluated the performance of a honeycomb-patterned poly(lactide) (HCPLA) film as a physical barrier for preventing postoperative adhesion. HCPLA films were prepared using dioleoylphosphatidylethanolamine (DOPE) or a copolymer of dodecylacrylamide and ω-carboxyhexylacrylamide (CAP) as a surfactant (HCPLA-DOPE and HCPLA-CAP, respectively). In an in vivo adhesion prevention experiment, male Sprague-Dawley rats underwent standard cecum abrasion before midline laparotomy. We placed 2 cm x 2 cm HCPLA and flat films on the gliding interfaces; untreated rats formed the control group. After 1 week, adhesion was scored from 0 to 4. No significant difference was observed in the scores among groups, but macroscopic differences in adhesion prevention were observed. The adhesive strength of HCPLA-DOPE (18.1 ± 1.2 g) to skinless chicken breast was significantly higher than that of the flat film (15.2 ± 0.8 g, p < 0.05). Further, the adhesion score after 1 week for the HCPLA-DOPE group (1.6 ± 0.2) was significantly lower than that for the control group (3.0 ±0.3, ñ< 0.05) but comparable to that for the Seprafilm™ group (1.4 ± 0.3). These results demonstrated the potential of HCPLA-DOPE as a physical barrier for preventing postoperative adhesion..
344. Akinori Tsuruma, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of neural stem cell differentiation on honeycomb films, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.079, 313-314, 536-540, 2008.02, Control of neural stem cell (NSC) differentiation is ongoing interest in neural tissue engineering. Formation of neural networks on various patterned substrates was reported in previous studies. In this study, we cultured NSCs derived from the cerebral cortex of embryonic day-14 mice on honeycomb (HC) films with highly regular pores prepared by casting a polymer solution of water-immiscible solvent under high humidity. The differentiation of NSCs was analyzed by immunostaining for Nestin and MAP2. The differentiation of NSC was controlled for the first time by manipulating the pore size on HC films. The highest suppression of NSC differentiation was observed on HC film with 3 μm pore specifically..
345. Yukako Fukuhira, Hiroaki Kaneko, Mika Yamaga, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of honeycomb-patterned structure on chondrocyte behavior in vitro, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.047, 313-314, 520-525, 2008.02, Chondrocytes were cultured on a honeycomb-patterned poly(lactic acid) (PLA) film in order to evaluate the effects of the honeycomb structure on chondrocytes with regard to cell proliferation, the production of sulphated glycosaminoglycans (sGAG), and morphological behavior. Cell proliferation was evaluated using the alamar blue assay, and sGAG production was spectrophotometrically quantified. Cell morphology was observed by means of optical microscopy (OM) and transmission electron microscopy (TEM). In comparison to the honeycomb-patterned film, the flat film showed significantly higher levels of chondrocyte growth; however, chondrocytes were flattened in a manner similar to that of fibroblasts and produced small amounts of extracellular matrix (ECM). On the contrary, chondrocytes cultured on the honeycomb-patterned film were observed to remain spherical shaped and produce ECM abundantly. The results indicate that the honeycomb-patterned structure reduced the points of attachment for the chondrocytes and that they have the potential to provide chondrocytes with a suitable environment for developing a spherical shape. The honeycomb-patterned structure of the PLA film may play an important role in determining chondrocyte behavior and as a scaffold that can be used in tissue engineering..
346. Keiko Arai, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of pore size of honeycomb films on the morphology, adhesion and cytoskeletal organization of cardiac myocytes, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.04.128, 313-314, 530-535, 2008.02, Cells respond to the circumstances such as structures and chemical composition of scaffolds and cytokine. In this report, the responses of cytoskeleton and spreading of cardiac myocytes to the self-organized honeycomb-patterned films (honeycomb films) of biodegradable poly(ε-caprolactone) (PCL) with several pore sizes were investigated. The expression of actin filament of cardiac myocytes was strongly dependent on the pore size ranging from 4 to 13 μm. Immunofluorescent labeling of vinculin in cardiac myocytes showed localization of focal contact along the edge of the honeycomb pores. The results indicated that the honeycomb structures and the pore sizes influence the morphology, cytoskeletal organization and focal adhesion of the cardiac myocytes..
347. Shusaku Tsukiyama, Michiaki Matsushita, Masaru Tanaka, Hitoshi Tamura, Satoru Todo, Sadaaki Yamamoto, Masatsugu Shimomura, Enhanced cell survival and yield of rat small hepatocytes by honeycomb-patterned films, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.47.1429, 47, 2 PART 2, 1429-1434, 2008.02, Surface designing of substrate to regulate cell adhesion and function in nano and micro scale is a critical issue in biomaterial science. In this study, we describe the fabrication of highly regular patterned porous films (honeycomb-patterned film) formed by a simply casting technique, and the culture of mature hepatocytes and small hepatocytes on the films. The pore size of the honeycomb-patterned films used was 6, 12, and 16 μm. We evaluated the effect of the honeycomb-patterned films on the morphology, cell yield, survival and the differentiated hepatic function (albumin production) of the both hepatocytes. Both hepatocytes attached on the flat films appeared to spread well, showing a typical monolayer morphology. They peeled off from the films at 7 days in culture on the flat films. On the other hand, spreading of the each hepatocytes was restricted on the honeycomb-patterned films at 3 and 7 days in culture. The cell yield and survival of the each hepatocytes increased with increasing culture time. Small hepatocyte on the pore sizes of 16 μm showed the highest cell yield (approximately 3 times). Albumin production of mature hepatocyte on the pore sizes of 16u.m (224.1.3 ± 157ng ml-1 well -1 at 1 day in culture, 369.5 ± 222 ng ml-1 well-1 at 3 days in culture) was higher than that of the hepatocytes on the flat films (119.3 ± 9.3 ng ml-1 well-1 at 1 day in culture, 262.8 ± 47.3 ng ml-1 well-1 at 3 days in culture), although that of small hepatocytes on the honeycomb-patterned films (pore size: 16 μm) was similar on the flat film. These results indicated that both the surface topography and the pore size of the honeycomb-patterned film affected the hepatic metabolic function..
348. Masaru Tanaka, Keiko Yoshizawa, Akinori Tsuruma, Hiroshi Sunami, Sadaaki Yamamoto, Masatsugu Shimomura, Formation of hydroxyapatite on a self-organized 3D honeycomb-patterned biodegradable polymer film, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.081, 313-314, 515-519, 2008.02, The design of nano- and microstructures based on self-organization is a key area of research in the search for new biomaterials, and such structures have a variety of potential applications in tissue engineering scaffolds. We have reported a honeycomb-patterned polymer film (honeycomb film) with highly regular pores that is formed by self-organization. In order to utilize the honeycomb film as a scaffold for bone tissue engineering, hydroxyapatite (HA) was formed on the honeycomb film. In this study, we prepared a 3D scaffold comprising HA and a poly(ε-caprolactone) honeycomb film in a simulated body fluid (SBF) by changing the degree of hydrophilicity of the film. We investigated the dependence of the amount of HA formed on the length of time for which hydrolysis and soaking in SBF were carried out. Further, we characterized the crystallinity of the HA thus formed. We clarified that the amount of HA formed and its crystallinity were controlled by the length of time for which hydrolysis and soaking of the film were carried out. These HA-deposited honeycomb films, which have the HA microstructure, could serve as a novel scaffold for bone tissue engineering..
349. Akinori Tsuruma, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of neural stem cell differentiation on honeycomb films, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.079, 313-314, 536-540, 2008.02, Control of neural stem cell (NSC) differentiation is ongoing interest in neural tissue engineering. Formation of neural networks on various patterned substrates was reported in previous studies. In this study, we cultured NSCs derived from the cerebral cortex of embryonic day-14 mice on honeycomb (HC) films with highly regular pores prepared by casting a polymer solution of water-immiscible solvent under high humidity. The differentiation of NSCs was analyzed by immunostaining for Nestin and MAP2. The differentiation of NSC was controlled for the first time by manipulating the pore size on HC films. The highest suppression of NSC differentiation was observed on HC film with 3 μm pore specifically..
350. Yukako Fukuhira, Hiroaki Kaneko, Mika Yamaga, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of honeycomb-patterned structure on chondrocyte behavior in vitro, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.047, 313-314, 520-525, 2008.02, Chondrocytes were cultured on a honeycomb-patterned poly(lactic acid) (PLA) film in order to evaluate the effects of the honeycomb structure on chondrocytes with regard to cell proliferation, the production of sulphated glycosaminoglycans (sGAG), and morphological behavior. Cell proliferation was evaluated using the alamar blue assay, and sGAG production was spectrophotometrically quantified. Cell morphology was observed by means of optical microscopy (OM) and transmission electron microscopy (TEM). In comparison to the honeycomb-patterned film, the flat film showed significantly higher levels of chondrocyte growth; however, chondrocytes were flattened in a manner similar to that of fibroblasts and produced small amounts of extracellular matrix (ECM). On the contrary, chondrocytes cultured on the honeycomb-patterned film were observed to remain spherical shaped and produce ECM abundantly. The results indicate that the honeycomb-patterned structure reduced the points of attachment for the chondrocytes and that they have the potential to provide chondrocytes with a suitable environment for developing a spherical shape. The honeycomb-patterned structure of the PLA film may play an important role in determining chondrocyte behavior and as a scaffold that can be used in tissue engineering..
351. Keiko Arai, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of pore size of honeycomb films on the morphology, adhesion and cytoskeletal organization of cardiac myocytes, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.04.128, 313-314, 530-535, 2008.02, Cells respond to the circumstances such as structures and chemical composition of scaffolds and cytokine. In this report, the responses of cytoskeleton and spreading of cardiac myocytes to the self-organized honeycomb-patterned films (honeycomb films) of biodegradable poly(ε-caprolactone) (PCL) with several pore sizes were investigated. The expression of actin filament of cardiac myocytes was strongly dependent on the pore size ranging from 4 to 13 μm. Immunofluorescent labeling of vinculin in cardiac myocytes showed localization of focal contact along the edge of the honeycomb pores. The results indicated that the honeycomb structures and the pore sizes influence the morphology, cytoskeletal organization and focal adhesion of the cardiac myocytes..
352. Shusaku Tsukiyama, Michiaki Matsushita, Masaru Tanaka, Hitoshi Tamura, Satoru Todo, Sadaaki Yamamoto, Masatsugu Shimomura, Enhanced cell survival and yield of rat small hepatocytes by honeycomb-patterned films, Japanese Journal of Applied Physics, 10.1143/JJAP.47.1429, 47, 2 PART 2, 1429-1434, 2008.02, Surface designing of substrate to regulate cell adhesion and function in nano and micro scale is a critical issue in biomaterial science. In this study, we describe the fabrication of highly regular patterned porous films (honeycomb-patterned film) formed by a simply casting technique, and the culture of mature hepatocytes and small hepatocytes on the films. The pore size of the honeycomb-patterned films used was 6, 12, and 16 μm. We evaluated the effect of the honeycomb-patterned films on the morphology, cell yield, survival and the differentiated hepatic function (albumin production) of the both hepatocytes. Both hepatocytes attached on the flat films appeared to spread well, showing a typical monolayer morphology. They peeled off from the films at 7 days in culture on the flat films. On the other hand, spreading of the each hepatocytes was restricted on the honeycomb-patterned films at 3 and 7 days in culture. The cell yield and survival of the each hepatocytes increased with increasing culture time. Small hepatocyte on the pore sizes of 16 μm showed the highest cell yield (approximately 3 times). Albumin production of mature hepatocyte on the pore sizes of 16u.m (224.1.3 ± 157ng ml-1 well -1 at 1 day in culture, 369.5 ± 222 ng ml-1 well-1 at 3 days in culture) was higher than that of the hepatocytes on the flat films (119.3 ± 9.3 ng ml-1 well-1 at 1 day in culture, 262.8 ± 47.3 ng ml-1 well-1 at 3 days in culture), although that of small hepatocytes on the honeycomb-patterned films (pore size: 16 μm) was similar on the flat film. These results indicated that both the surface topography and the pore size of the honeycomb-patterned film affected the hepatic metabolic function..
353. Masaru Tanaka, Keiko Yoshizawa, Akinori Tsuruma, Hiroshi Sunami, Sadaaki Yamamoto, Masatsugu Shimomura, Formation of hydroxyapatite on a self-organized 3D honeycomb-patterned biodegradable polymer film, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.081, 313-314, 515-519, 2008.02, The design of nano- and microstructures based on self-organization is a key area of research in the search for new biomaterials, and such structures have a variety of potential applications in tissue engineering scaffolds. We have reported a honeycomb-patterned polymer film (honeycomb film) with highly regular pores that is formed by self-organization. In order to utilize the honeycomb film as a scaffold for bone tissue engineering, hydroxyapatite (HA) was formed on the honeycomb film. In this study, we prepared a 3D scaffold comprising HA and a poly(ε-caprolactone) honeycomb film in a simulated body fluid (SBF) by changing the degree of hydrophilicity of the film. We investigated the dependence of the amount of HA formed on the length of time for which hydrolysis and soaking in SBF were carried out. Further, we characterized the crystallinity of the HA thus formed. We clarified that the amount of HA formed and its crystallinity were controlled by the length of time for which hydrolysis and soaking of the film were carried out. These HA-deposited honeycomb films, which have the HA microstructure, could serve as a novel scaffold for bone tissue engineering..
354. Akinori Tsuruma, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of neural stem cell differentiation on honeycomb films, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.079, 313-314, 536-540, 2008.02, Control of neural stem cell (NSC) differentiation is ongoing interest in neural tissue engineering. Formation of neural networks on various patterned substrates was reported in previous studies. In this study, we cultured NSCs derived from the cerebral cortex of embryonic day-14 mice on honeycomb (HC) films with highly regular pores prepared by casting a polymer solution of water-immiscible solvent under high humidity. The differentiation of NSCs was analyzed by immunostaining for Nestin and MAP2. The differentiation of NSC was controlled for the first time by manipulating the pore size on HC films. The highest suppression of NSC differentiation was observed on HC film with 3 μm pore specifically..
355. Yukako Fukuhira, Hiroaki Kaneko, Mika Yamaga, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of honeycomb-patterned structure on chondrocyte behavior in vitro, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.047, 313-314, 520-525, 2008.02, Chondrocytes were cultured on a honeycomb-patterned poly(lactic acid) (PLA) film in order to evaluate the effects of the honeycomb structure on chondrocytes with regard to cell proliferation, the production of sulphated glycosaminoglycans (sGAG), and morphological behavior. Cell proliferation was evaluated using the alamar blue assay, and sGAG production was spectrophotometrically quantified. Cell morphology was observed by means of optical microscopy (OM) and transmission electron microscopy (TEM). In comparison to the honeycomb-patterned film, the flat film showed significantly higher levels of chondrocyte growth; however, chondrocytes were flattened in a manner similar to that of fibroblasts and produced small amounts of extracellular matrix (ECM). On the contrary, chondrocytes cultured on the honeycomb-patterned film were observed to remain spherical shaped and produce ECM abundantly. The results indicate that the honeycomb-patterned structure reduced the points of attachment for the chondrocytes and that they have the potential to provide chondrocytes with a suitable environment for developing a spherical shape. The honeycomb-patterned structure of the PLA film may play an important role in determining chondrocyte behavior and as a scaffold that can be used in tissue engineering..
356. Keiko Arai, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of pore size of honeycomb films on the morphology, adhesion and cytoskeletal organization of cardiac myocytes, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.04.128, 313-314, 530-535, 2008.02, Cells respond to the circumstances such as structures and chemical composition of scaffolds and cytokine. In this report, the responses of cytoskeleton and spreading of cardiac myocytes to the self-organized honeycomb-patterned films (honeycomb films) of biodegradable poly(ε-caprolactone) (PCL) with several pore sizes were investigated. The expression of actin filament of cardiac myocytes was strongly dependent on the pore size ranging from 4 to 13 μm. Immunofluorescent labeling of vinculin in cardiac myocytes showed localization of focal contact along the edge of the honeycomb pores. The results indicated that the honeycomb structures and the pore sizes influence the morphology, cytoskeletal organization and focal adhesion of the cardiac myocytes..
357. Shusaku Tsukiyama, Michiaki Matsushita, Masaru Tanaka, Hitoshi Tamura, Satoru Todo, Sadaaki Yamamoto, Masatsugu Shimomura, Enhanced cell survival and yield of rat small hepatocytes by honeycomb-patterned films, Japanese Journal of Applied Physics, 10.1143/JJAP.47.1429, 47, 2 PART 2, 1429-1434, 2008.02, Surface designing of substrate to regulate cell adhesion and function in nano and micro scale is a critical issue in biomaterial science. In this study, we describe the fabrication of highly regular patterned porous films (honeycomb-patterned film) formed by a simply casting technique, and the culture of mature hepatocytes and small hepatocytes on the films. The pore size of the honeycomb-patterned films used was 6, 12, and 16 μm. We evaluated the effect of the honeycomb-patterned films on the morphology, cell yield, survival and the differentiated hepatic function (albumin production) of the both hepatocytes. Both hepatocytes attached on the flat films appeared to spread well, showing a typical monolayer morphology. They peeled off from the films at 7 days in culture on the flat films. On the other hand, spreading of the each hepatocytes was restricted on the honeycomb-patterned films at 3 and 7 days in culture. The cell yield and survival of the each hepatocytes increased with increasing culture time. Small hepatocyte on the pore sizes of 16 μm showed the highest cell yield (approximately 3 times). Albumin production of mature hepatocyte on the pore sizes of 16u.m (224.1.3 ± 157ng ml-1 well -1 at 1 day in culture, 369.5 ± 222 ng ml-1 well-1 at 3 days in culture) was higher than that of the hepatocytes on the flat films (119.3 ± 9.3 ng ml-1 well-1 at 1 day in culture, 262.8 ± 47.3 ng ml-1 well-1 at 3 days in culture), although that of small hepatocytes on the honeycomb-patterned films (pore size: 16 μm) was similar on the flat film. These results indicated that both the surface topography and the pore size of the honeycomb-patterned film affected the hepatic metabolic function..
358. Masaru Tanaka, Keiko Yoshizawa, Akinori Tsuruma, Hiroshi Sunami, Sadaaki Yamamoto, Masatsugu Shimomura, Formation of hydroxyapatite on a self-organized 3D honeycomb-patterned biodegradable polymer film, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2007.05.081, 313-314, 515-519, 2008.02, The design of nano- and microstructures based on self-organization is a key area of research in the search for new biomaterials, and such structures have a variety of potential applications in tissue engineering scaffolds. We have reported a honeycomb-patterned polymer film (honeycomb film) with highly regular pores that is formed by self-organization. In order to utilize the honeycomb film as a scaffold for bone tissue engineering, hydroxyapatite (HA) was formed on the honeycomb film. In this study, we prepared a 3D scaffold comprising HA and a poly(ε-caprolactone) honeycomb film in a simulated body fluid (SBF) by changing the degree of hydrophilicity of the film. We investigated the dependence of the amount of HA formed on the length of time for which hydrolysis and soaking in SBF were carried out. Further, we characterized the crystallinity of the HA thus formed. We clarified that the amount of HA formed and its crystallinity were controlled by the length of time for which hydrolysis and soaking of the film were carried out. These HA-deposited honeycomb films, which have the HA microstructure, could serve as a novel scaffold for bone tissue engineering..
359. Akiko Tanabe, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Multivariate curve resolution analysis on the multi-component water sorption process into a poly(2-methoxyethyl acrylate) film, Applied Spectroscopy, 10.1366/000370208783412555, 62, 1, 46-50, 2008.01, In our previous study, sorption process of water into a biocompatible polymer film, poly(2-methoxyethyl acrylate) (PMEA) was monitored by time-resolved in situ attenuated total reflection infrared (ATR-IR) spectroscopy [S. Morita, et al., Langmuir 23, 3750 (2007)]. In the present study, noisy and heavily overlapped O-H stretching vibrational bands of diffusing water have been analyzed from the series spectra where the spectral shapes change irregularly with time. In spite of these complications, a powerful spectral analysis technique, multivariate curve resolution (MCR) by means of alternating least squares (ALS), yielded smooth and meaningful pure component spectra and detailed kinetic sorption profiles of each component, excluding noise. Ordinary smoothing techniques and Gaussian curve fitting would not achieve these significant results. The quantification of the kinetic parameters such as amplitudes (a) and relaxation time constants (τ) is significant for the systematic development of biocompatible materials and also for revealing the mechanisms of biocompatibility of a material. Moreover, the ratios of coefficients of each component at saturation corresponded well to the values obtained by Tanaka et al. measured by gravimetric analysis. This study is the first to report the detailed concentration profile of each water component whose sorption kinetics is discussed comprehensively..
360. Hiromi Kitano, Kyoko Nagaoka, Susumu Tada, Makoto Gemmei-Ide, Masaru Tanaka, Structure of water incorporated in amphoteric polymer thin films as revealed by FT-IR spectroscopy, Macromolecular Bioscience, 10.1002/mabi.200700082, 8, 1, 77-85, 2008.01, The structure and hydrogen bonding of water incorporated in a thin film of amphoteric terpolymers composed of various ratios of MA, DMAPMA, and BMA were analyzed using the band shapes of the O-H stretching in the IR spectra. At an early stage of sorption of water, the IR spectrum for the water incorporated in the film with comparative contents of MA and DMAPMA residues was similar to that for free water. This is consistent with the tendency for zwitterionic polymers, but is in contrast with the drastic change in the IR spectrum of water incorporated in non-ionic polymer films such as polyBMA. These results suggest a correlation between the mildness of the charge-balanced polymers to the structure of incorporated water and their blood compatibilities. (Table Presented).
361. Akiko Tanabe, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Multivariate curve resolution analysis on the multi-component water sorption process into a poly(2-methoxyethyl acrylate) film, Applied Spectroscopy, 10.1366/000370208783412555, 62, 1, 46-50, 2008.01, In our previous study, sorption process of water into a biocompatible polymer film, poly(2-methoxyethyl acrylate) (PMEA) was monitored by time-resolved in situ attenuated total reflection infrared (ATR-IR) spectroscopy [S. Morita, et al., Langmuir 23, 3750 (2007)]. In the present study, noisy and heavily overlapped O-H stretching vibrational bands of diffusing water have been analyzed from the series spectra where the spectral shapes change irregularly with time. In spite of these complications, a powerful spectral analysis technique, multivariate curve resolution (MCR) by means of alternating least squares (ALS), yielded smooth and meaningful pure component spectra and detailed kinetic sorption profiles of each component, excluding noise. Ordinary smoothing techniques and Gaussian curve fitting would not achieve these significant results. The quantification of the kinetic parameters such as amplitudes (a) and relaxation time constants (τ) is significant for the systematic development of biocompatible materials and also for revealing the mechanisms of biocompatibility of a material. Moreover, the ratios of coefficients of each component at saturation corresponded well to the values obtained by Tanaka et al. measured by gravimetric analysis. This study is the first to report the detailed concentration profile of each water component whose sorption kinetics is discussed comprehensively..
362. Hiromi Kitano, Kyoko Nagaoka, Susumu Tada, Makoto Gemmei-Ide, Masaru Tanaka, Structure of water incorporated in amphoteric polymer thin films as revealed by FT-IR spectroscopy, Macromolecular Bioscience, 10.1002/mabi.200700082, 8, 1, 77-85, 2008.01, The structure and hydrogen bonding of water incorporated in a thin film of amphoteric terpolymers composed of various ratios of MA, DMAPMA, and BMA were analyzed using the band shapes of the O-H stretching in the IR spectra. At an early stage of sorption of water, the IR spectrum for the water incorporated in the film with comparative contents of MA and DMAPMA residues was similar to that for free water. This is consistent with the tendency for zwitterionic polymers, but is in contrast with the drastic change in the IR spectrum of water incorporated in non-ionic polymer films such as polyBMA. These results suggest a correlation between the mildness of the charge-balanced polymers to the structure of incorporated water and their blood compatibilities. (Table Presented).
363. Akiko Tanabe, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Multivariate curve resolution analysis on the multi-component water sorption process into a poly(2-methoxyethyl acrylate) film, Applied Spectroscopy, 10.1366/000370208783412555, 62, 1, 46-50, 2008.01, In our previous study, sorption process of water into a biocompatible polymer film, poly(2-methoxyethyl acrylate) (PMEA) was monitored by time-resolved in situ attenuated total reflection infrared (ATR-IR) spectroscopy [S. Morita, et al., Langmuir 23, 3750 (2007)]. In the present study, noisy and heavily overlapped O-H stretching vibrational bands of diffusing water have been analyzed from the series spectra where the spectral shapes change irregularly with time. In spite of these complications, a powerful spectral analysis technique, multivariate curve resolution (MCR) by means of alternating least squares (ALS), yielded smooth and meaningful pure component spectra and detailed kinetic sorption profiles of each component, excluding noise. Ordinary smoothing techniques and Gaussian curve fitting would not achieve these significant results. The quantification of the kinetic parameters such as amplitudes (a) and relaxation time constants (τ) is significant for the systematic development of biocompatible materials and also for revealing the mechanisms of biocompatibility of a material. Moreover, the ratios of coefficients of each component at saturation corresponded well to the values obtained by Tanaka et al. measured by gravimetric analysis. This study is the first to report the detailed concentration profile of each water component whose sorption kinetics is discussed comprehensively..
364. Hiromi Kitano, Kyoko Nagaoka, Susumu Tada, Makoto Gemmei-Ide, Masaru Tanaka, Structure of water incorporated in amphoteric polymer thin films as revealed by FT-IR spectroscopy, Macromolecular Bioscience, 10.1002/mabi.200700082, 8, 1, 77-85, 2008.01, The structure and hydrogen bonding of water incorporated in a thin film of amphoteric terpolymers composed of various ratios of MA, DMAPMA, and BMA were analyzed using the band shapes of the O-H stretching in the IR spectra. At an early stage of sorption of water, the IR spectrum for the water incorporated in the film with comparative contents of MA and DMAPMA residues was similar to that for free water. This is consistent with the tendency for zwitterionic polymers, but is in contrast with the drastic change in the IR spectrum of water incorporated in non-ionic polymer films such as polyBMA. These results suggest a correlation between the mildness of the charge-balanced polymers to the structure of incorporated water and their blood compatibilities. (Table Presented).
365. Hiromi Kitano, Kyoko Nagaoka, Susumu Tada, Makoto Gemmei-Ide, Masaru Tanaka, Structure of water incorporated in amphoteric polymer thin films as revealed by FT-IR spectroscopy, MACROMOLECULAR BIOSCIENCE, 10.1002/mabi.200700082, 8, 1, 77-85, 2008.01, The structure and hydrogen bonding of water incorporated in a thin film of amphoteric terpolymers composed of various ratios of MA, DMAPMA, and BMA were analyzed using the band shapes of the O-H stretching in the IR spectra. At an early stage of sorption of water, the IR spectrum for the water incorporated in the film with comparative contents of MA and DMAPMA residues was similar to that for free water. This is consistent with the tendency for zwitterionic polymers, but is in contrast with the drastic change in the IR spectrum of water incorporated in non-ionic polymer films such as polyBMA. These results suggest a correlation between the mildness of the charge-balanced polymers to the structure of incorporated water and their blood compatibilities.
[GRAPHICS].
366. Masaru Tanaka, Akinori Tsuruma, Yuka Morita, Nobuyuki Fukushima, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell proliferation and differentiation using self-organized honeycomb-patterned films, 8th World Biomaterials Congress 2008, WBC 2008 8th World Biomaterials Congress 2008, 4, 2254, 2008.
367. Mark Birch, Masaru Tanaka, George Kirmizidis, Ito Emiko, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, 8th World Biomaterials Congress 2008, WBC 2008 8th World Biomaterials Congress 2008, 2, 836, 2008.
368. Masaru Tanaka, Akinori Tsuruma, Yuka Morita, Nobuyuki Fukushima, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell proliferation and differentiation using self-organized honeycomb-patterned films, 8th World Biomaterials Congress 2008, WBC 2008 8th World Biomaterials Congress 2008, 4, 2254, 2008.
369. Mark Birch, Masaru Tanaka, George Kirmizidis, Ito Emiko, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, 8th World Biomaterials Congress 2008, WBC 2008 8th World Biomaterials Congress 2008, 2, 836, 2008.
370. Masaru Tanaka, Akinori Tsuruma, Yuka Morita, Nobuyuki Fukushima, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cell proliferation and differentiation using self-organized honeycomb-patterned films, 8th World Biomaterials Congress 2008, WBC 2008 8th World Biomaterials Congress 2008, 4, 2254, 2008.
371. Mark Birch, Masaru Tanaka, George Kirmizidis, Ito Emiko, Sadaaki Yamamoto, Masatsugu Shimomura, Microporous "honeycomb" films support enhanced bone formation in vitro, 8th World Biomaterials Congress 2008, WBC 2008 8th World Biomaterials Congress 2008, 2, 836, 2008.
372. Tatsuko Hatakeyma, Hazuki Kasuga, Masaru Tanaka, Hyoe Hatakeyama, Cold crystallization of poly(ethylene glycol)-water systems, Thermochimica Acta, 10.1016/j.tca.2007.09.005, 465, 1-2, 59-66, 2007.12, Phase transition behaviour of poly(ethylene glycol) (PEG)-water systems was investigated by differential scanning calorimetry (DSC) in a temperature range from 150 to 350 K and water content (mass of water/mass of PEG) range from 0 to 10 g g-1. In DSC heating curves, glass transition, cold crystallization, melting of eutectic crystal, water and PEG crystal were observed depending on water content. The cold crystallization of the system, which is thought to be used as an index of biocompatibility of polymer-water interaction, received particular attention. It was found that cold crystallization and glass transition were observed in a wide water content range from 0.05 to 10 g g-1. From the enthalpy balance of transitions in both heating and cooling DSC curves, it was confirmed that cold crystallization is attributable to the molecular rearrangement of PEG molecules associated with amorphous ice. When four water molecules are attached to one repeating unit of PEG, the heat capacity difference at glass transition temperature attains the largest value and the enthalpy of cold crystallization shows the maximum value..
373. Tatsuko Hatakeyma, Hazuki Kasuga, Masaru Tanaka, Hyoe Hatakeyama, Cold crystallization of poly(ethylene glycol)-water systems, Thermochimica Acta, 10.1016/j.tca.2007.09.005, 465, 1-2, 59-66, 2007.12, Phase transition behaviour of poly(ethylene glycol) (PEG)-water systems was investigated by differential scanning calorimetry (DSC) in a temperature range from 150 to 350 K and water content (mass of water/mass of PEG) range from 0 to 10 g g-1. In DSC heating curves, glass transition, cold crystallization, melting of eutectic crystal, water and PEG crystal were observed depending on water content. The cold crystallization of the system, which is thought to be used as an index of biocompatibility of polymer-water interaction, received particular attention. It was found that cold crystallization and glass transition were observed in a wide water content range from 0.05 to 10 g g-1. From the enthalpy balance of transitions in both heating and cooling DSC curves, it was confirmed that cold crystallization is attributable to the molecular rearrangement of PEG molecules associated with amorphous ice. When four water molecules are attached to one repeating unit of PEG, the heat capacity difference at glass transition temperature attains the largest value and the enthalpy of cold crystallization shows the maximum value..
374. Tatsuko Hatakeyma, Hazuki Kasuga, Masaru Tanaka, Hyoe Hatakeyama, Cold crystallization of poly(ethylene glycol)-water systems, Thermochimica Acta, 10.1016/j.tca.2007.09.005, 465, 1-2, 59-66, 2007.12, Phase transition behaviour of poly(ethylene glycol) (PEG)-water systems was investigated by differential scanning calorimetry (DSC) in a temperature range from 150 to 350 K and water content (mass of water/mass of PEG) range from 0 to 10 g g-1. In DSC heating curves, glass transition, cold crystallization, melting of eutectic crystal, water and PEG crystal were observed depending on water content. The cold crystallization of the system, which is thought to be used as an index of biocompatibility of polymer-water interaction, received particular attention. It was found that cold crystallization and glass transition were observed in a wide water content range from 0.05 to 10 g g-1. From the enthalpy balance of transitions in both heating and cooling DSC curves, it was confirmed that cold crystallization is attributable to the molecular rearrangement of PEG molecules associated with amorphous ice. When four water molecules are attached to one repeating unit of PEG, the heat capacity difference at glass transition temperature attains the largest value and the enthalpy of cold crystallization shows the maximum value..
375. Tatsuko Hatakeyma, Hazuki Kasuga, Masaru Tanaka, Hyoe Hatakeyama, Cold crystallization of poly(ethylene glycol)-water systems, THERMOCHIMICA ACTA, 10.1016/j.tca.2007.09.005, 465, 1-2, 59-66, 2007.12, Phase transition behaviour of poly(ethylene glycol) (PEG)-water systems was investigated by differential scanning calorimetry (DSC) in a temperature range from 150 to 350K and water content (mass of water/mass of PEG) range from 0 to 10gg(-1). In DSC heating curves, glass transition, cold crystallization, melting of eutectic crystal, water and PEG crystal were observed depending on water content. The cold crystallization of the system, which is thought to be used as an index of biocompatibility of polymer-water interaction, received particular attention. It was found that cold crystallization and glass transition were observed in a wide water content range from 0.05 to 10gg(-1). From the enthalpy balance of transitions in both heating and cooling DSC curves, it was confirmed that cold crystallization is attributable to the molecular rearrangement of PEG molecules associated with amorphous ice. When four water molecules are attached to one repeating unit of PEG, the heat capacity difference at glass transition temperature attains the largest value and the enthalpy of cold crystallization shows the maximum value. (C) 2007 Published by Elsevier B.V..
376. Tomohiro Hayashi, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Masahiko Hara, Direct observation of interaction between proteins and blood-compatible polymer surfaces, BIOINTERPHASES, 10.1116/1.2794712, 2, 4, 119-125, 2007.12, The adhesion force between blood-compatible polymer (poly(2- methoxyethyl acrylate: PMEA) and proteins ( fibrinogen and bovine serum albumin (BSA)) were measured by atomic force microscopy. The PMEA surface showed almost no adhesion to native protein molecules, whereas non-blood- compatible poly (n- butyl acrylate): PBA strongly adhered to proteins. Interestingly, adhesion did appear between PMEA and proteins when the proteins were denatured. In all cases, these trends were not affected by the conditions of the solution. Combining the results with previous reports, the authors conclude that interfacial water molecules play a critical role in the protein resistance of PMEA. (c) 2007 American Vacuum Society..
377. Shigeaki Morita, Masaru Tanaka, Isao Noda, Yukihiro Ozaki, Phase angle description of perturbation correlation analysis and its application to time-resolved infrared spectra, Applied Spectroscopy, 10.1366/000370207781540051, 61, 8, 867-872, 2007.08, A method of spectral analysis, phase angle description of perturbation correlation analysis, is proposed. This method is based on global phase angle description of generalized two-dimensional (2D) correlation spectroscopy, proposed by Shin-ichi Morita et al., and perturbationcorrelation moving-window 2D (PCMW2D) correlation spectroscopy, proposed by Shigeaki Morita et al. For a spectral data set collected under an external perturbation, such as time-resolved infrared spectra, this method provides only one phase angle spectrum. A phase angle of the Fourier frequency domain correlation between a spectral intensity (e.g., absorbance) variation and a perturbation variation (e.g., scores of the first principle component) as a function of spectral variable (e.g., wavenumber) is plotted. Therefore, a degree of time lag of each band variation with respect to the perturbation variation is directly visualized in the phase angle spectrum. This method is applied to time-resolved infrared spectra in the O-H stretching region of the water sorption process into a poly (2-methoxyethyl acrylate) (PMEA) film. The time-resolved infrared (IR) spectra show three broad and overlapping bands in the region. Each band increases toward saturated water sorption with different relaxation times. In comparison to conventional methods of generalized 2D correlation spectroscopy and global phase angle mapping, the method proposed in the present study enables the easier visualization of the sequence as a degree of phase angle in the spectrum..
378. Takaharu Okajima, Masaru Tanaka, Shusaku Tsukiyama, Tsubasa Kadowaki, Sadaaki Yamamoto, Masatsugu Shimomura, Hiroshi Tokumoto, Stress relaxation measurement of fibroblast cells with atomic force microscopy, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.1143/JJAP.46.5552, 46, 8 B, 5552-5555, 2007.08, We measured the stress relaxation of mouse fibroblast NIH3T3 cells with an atomic force microscope (AFM) using a sharp silicon tip and a silica bead with a radius of ∼1 μm as an indenter. The decay of loading force was clearly observed in NIH3T3 cells at a small initial loading force of ∼0.4 nN and was well fitted to the stretched exponential function rather than to a single exponential function. The stretching exponent parameter was ∼0.5 for both indenters, indicating that the stress relaxation observed in NIH3T3 cells consisted of multiple relaxation processes. The time-domain AFM technique described in this report allows us to measure directly the relaxation process of living cells in a range from milliseconds to seconds..
379. Shigeaki Morita, Masaru Tanaka, Isao Noda, Yukihiro Ozaki, Phase angle description of perturbation correlation analysis and its application to time-resolved infrared spectra, Applied Spectroscopy, 10.1366/000370207781540051, 61, 8, 867-872, 2007.08, A method of spectral analysis, phase angle description of perturbation correlation analysis, is proposed. This method is based on global phase angle description of generalized two-dimensional (2D) correlation spectroscopy, proposed by Shin-ichi Morita et al., and perturbationcorrelation moving-window 2D (PCMW2D) correlation spectroscopy, proposed by Shigeaki Morita et al. For a spectral data set collected under an external perturbation, such as time-resolved infrared spectra, this method provides only one phase angle spectrum. A phase angle of the Fourier frequency domain correlation between a spectral intensity (e.g., absorbance) variation and a perturbation variation (e.g., scores of the first principle component) as a function of spectral variable (e.g., wavenumber) is plotted. Therefore, a degree of time lag of each band variation with respect to the perturbation variation is directly visualized in the phase angle spectrum. This method is applied to time-resolved infrared spectra in the O-H stretching region of the water sorption process into a poly (2-methoxyethyl acrylate) (PMEA) film. The time-resolved infrared (IR) spectra show three broad and overlapping bands in the region. Each band increases toward saturated water sorption with different relaxation times. In comparison to conventional methods of generalized 2D correlation spectroscopy and global phase angle mapping, the method proposed in the present study enables the easier visualization of the sequence as a degree of phase angle in the spectrum..
380. Takaharu Okajima, Masaru Tanaka, Shusaku Tsukiyama, Tsubasa Kadowaki, Sadaaki Yamamoto, Masatsugu Shimomura, Hiroshi Tokumoto, Stress relaxation measurement of fibroblast cells with atomic force microscopy, Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, 10.1143/JJAP.46.5552, 46, 8 B, 5552-5555, 2007.08, We measured the stress relaxation of mouse fibroblast NIH3T3 cells with an atomic force microscope (AFM) using a sharp silicon tip and a silica bead with a radius of ∼1 μm as an indenter. The decay of loading force was clearly observed in NIH3T3 cells at a small initial loading force of ∼0.4 nN and was well fitted to the stretched exponential function rather than to a single exponential function. The stretching exponent parameter was ∼0.5 for both indenters, indicating that the stress relaxation observed in NIH3T3 cells consisted of multiple relaxation processes. The time-domain AFM technique described in this report allows us to measure directly the relaxation process of living cells in a range from milliseconds to seconds..
381. Shigeaki Morita, Masaru Tanaka, Isao Noda, Yukihiro Ozaki, Phase angle description of perturbation correlation analysis and its application to time-resolved infrared spectra, Applied Spectroscopy, 10.1366/000370207781540051, 61, 8, 867-872, 2007.08, A method of spectral analysis, phase angle description of perturbation correlation analysis, is proposed. This method is based on global phase angle description of generalized two-dimensional (2D) correlation spectroscopy, proposed by Shin-ichi Morita et al., and perturbationcorrelation moving-window 2D (PCMW2D) correlation spectroscopy, proposed by Shigeaki Morita et al. For a spectral data set collected under an external perturbation, such as time-resolved infrared spectra, this method provides only one phase angle spectrum. A phase angle of the Fourier frequency domain correlation between a spectral intensity (e.g., absorbance) variation and a perturbation variation (e.g., scores of the first principle component) as a function of spectral variable (e.g., wavenumber) is plotted. Therefore, a degree of time lag of each band variation with respect to the perturbation variation is directly visualized in the phase angle spectrum. This method is applied to time-resolved infrared spectra in the O-H stretching region of the water sorption process into a poly (2-methoxyethyl acrylate) (PMEA) film. The time-resolved infrared (IR) spectra show three broad and overlapping bands in the region. Each band increases toward saturated water sorption with different relaxation times. In comparison to conventional methods of generalized 2D correlation spectroscopy and global phase angle mapping, the method proposed in the present study enables the easier visualization of the sequence as a degree of phase angle in the spectrum..
382. Takaharu Okajima, Masara Tanaka, Shusaku Tsukiyama, Tsubasa Kadowaki, Sadaaki Yamamoto, Masatsugu Shimomura, Hiroshi Tokumoto, Stress relaxation measurement of fibroblast cells with atomic force microscopy, Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, 10.1143/JJAP.46.5552, 46, 8 B, 5552-5555, 2007.08, We measured the stress relaxation of mouse fibroblast NIH3T3 cells with an atomic force microscope (AFM) using a sharp silicon tip and a silica bead with a radius of ∼1 μm as an indenter. The decay of loading force was clearly observed in NIH3T3 cells at a small initial loading force of ∼0.4 nN and was well fitted to the stretched exponential function rather than to a single exponential function. The stretching exponent parameter was ∼0.5 for both indenters, indicating that the stress relaxation observed in NIH3T3 cells consisted of multiple relaxation processes. The time-domain AFM technique described in this report allows us to measure directly the relaxation process of living cells in a range from milliseconds to seconds..
383. Shigeaki Morita, Masaru Tanaka, Isao Noda, Yukihiro Ozaki, Phase angle description of perturbation correlation analysis and its application to time-resolved infrared spectra, APPLIED SPECTROSCOPY, 10.1366/000370207781540051, 61, 8, 867-872, 2007.08, A method of spectral analysis, phase angle description of perturbation correlation analysis, is proposed. This method is based on global phase angle description of generalized two-dimensional (2D) correlation spectroscopy, proposed by Shin-ichi Morita et al., and perturbation-correlation moving-window 2D (PCMW2D) correlation spectroscopy, proposed by Shigeaki Morita et al. For a spectral data set collected under an external perturbation, such as time-resolved infrared spectra, this method provides only one phase angle spectrum. A phase angle of the Fourier frequency domain correlation between a spectral intensity (e.g., absorbance) variation and a perturbation variation (e.g., scores of the first principle component) as a function of spectral variable (e.g., wavenumber) is plotted. Therefore, a degree of time lag of each band variation with respect to the perturbation variation is directly visualized in the phase angle spectrum. This method is applied to time-resolved infrared spectra in the O-H stretching region of the water sorption process into a poly(2-methoxyethyl acrylate) (PMEA) film. The time-resolved infrared (IR) spectra show three broad and overlapping bands in the region. Each band increases toward saturated water sorption with different relaxation times. In comparison to conventional methods of generalized 2D correlation spectroscopy and global phase angle mapping, the method proposed in the present study enables the easier visualization of the sequence as a degree of phase angle in the spectrum..
384. Takaharu Okajima, Masaru Tanaka, Shusaku Tsukiyama, Tsubasa Kadowaki, Sadaaki Yamamoto, Masatsugu Shimomura, Hiroshi Tokumot, Stress relaxation measurement of fibroblast cells with atomic force microscopy, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 10.1143/JJAP.46.5552, 46, 8B, 5552-5555, 2007.08, We measured the stress relaxation of mouse fibroblast NIH3T3 cells with an atomic force microscope (AFM) using a sharp silicon tip and a silica bead with a radius of similar to 1 mu m as an indenter. The decay of loading force was clearly observed in NIH3T3 cells at a small initial loading force of similar to 0.4 nN and was well fitted to the stretched exponential function rather than to a single exponential function. The stretching exponent parameter was similar to 0.5 for both indenters, indicating that the stress relaxation observed in NIH3T3 cells consisted of multiple relaxation processes. The time-domain AFM technique described in this report allows us to measure directly the relaxation process of living cells in a range from milliseconds to seconds..
385. The Influence of Pore Size of a Honeycomb Film on Early Spreading Process of Endothelial Cells.
386. S. Yamamoto, Masaru Tanaka, H. Sunami, E. Ito, S. Yamashita, Y. Morita, M. Shimomura, Effect of honeycomb-patterned surface topography on the adhesion and signal transduction of porcine aortic endothelial cells, Langmuir, 10.1021/la7003326, 23, 15, 8114-8120, 2007.07, Surface topography has vital roles in cellular response. Here, to investigate the mechanism behind cellular response to surface topography, we prepared honeycomb (HC)-patterned films from poly(ε-caprolactone) (PCL) with micropatterned surface topography by casting a polymer solution of water-immiscible solvent under high humidity. We characterized the adsorption of fibronectin (Fn) on the film using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The response of porcine aortic endothelial cells (PAECs) to adsorbed Fn molecules onto HC-patterned films was observed by immunofluorescence labeling of vinculin and the actin fiber of PAECs cultured for 1 and 72 h in serum-free medium. The expression of focal adhesion kinase autophosphorylated at the tyrosine residue (pFAK) at 1 h culture was determined using an immunoprecipitation method. Fn adsorbed selectively around the pore edges to form ring-shaped aggregates. The immunostaining results revealed that PAECs adhered to the HC-patterned films at focal contact points localized around pore peripheries. These points correspond to adsorption sites of Fn. The expression of pFAK after 1 h on the HC-patterned film was 3 times higher than that on a corresponding flat film, indicating that the signaling mediated by the binding between Fn and the integrin receptor was more highly activated on the HC-patterned film. These results suggest that the cellular response to HC-patterned films (e.g., adhesion pattern and phosphorylation of FAK) originates from the regularly aligned adsorption pattern of Fn determined by the pore structure of the film..
387. S. Yamamoto, Masaru Tanaka, H. Sunami, E. Ito, S. Yamashita, Y. Morita, M. Shimomura, Effect of honeycomb-patterned surface topography on the adhesion and signal transduction of porcine aortic endothelial cells, Langmuir, 10.1021/la7003326, 23, 15, 8114-8120, 2007.07, Surface topography has vital roles in cellular response. Here, to investigate the mechanism behind cellular response to surface topography, we prepared honeycomb (HC)-patterned films from poly(ε-caprolactone) (PCL) with micropatterned surface topography by casting a polymer solution of water-immiscible solvent under high humidity. We characterized the adsorption of fibronectin (Fn) on the film using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The response of porcine aortic endothelial cells (PAECs) to adsorbed Fn molecules onto HC-patterned films was observed by immunofluorescence labeling of vinculin and the actin fiber of PAECs cultured for 1 and 72 h in serum-free medium. The expression of focal adhesion kinase autophosphorylated at the tyrosine residue (pFAK) at 1 h culture was determined using an immunoprecipitation method. Fn adsorbed selectively around the pore edges to form ring-shaped aggregates. The immunostaining results revealed that PAECs adhered to the HC-patterned films at focal contact points localized around pore peripheries. These points correspond to adsorption sites of Fn. The expression of pFAK after 1 h on the HC-patterned film was 3 times higher than that on a corresponding flat film, indicating that the signaling mediated by the binding between Fn and the integrin receptor was more highly activated on the HC-patterned film. These results suggest that the cellular response to HC-patterned films (e.g., adhesion pattern and phosphorylation of FAK) originates from the regularly aligned adsorption pattern of Fn determined by the pore structure of the film..
388. S. Yamamoto, M. Tanaka, H. Sunami, E. Ito, S. Yamashita, Y. Morita, M. Shimomura, Effect of honeycomb-patterned surface topography on the adhesion and signal transduction of porcine aortic endothelial cells, LANGMUIR, 10.1021/1a7003326, 23, 15, 8114-8120, 2007.07, Surface topography has vital roles in cellular response. Here, to investigate the mechanism behind cellular response to surface topography, we prepared honeycomb (HC)-patterned films from poly(epsilon-caprolactone) (PCL) with micropatterned surface topography by casting a polymer solution of water-immiscible solvent under high humidity. We characterized the adsorption of fibronectin (Fn) on the film using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The response of porcine aortic endothelial cells (PAECs) to adsorbed Fn molecules onto HC-patterned films was observed by immunofluorescence labeling of vinculin and the actin fiber of PAECs cultured for 1 and 72 h in serum-free medium. The expression of focal adhesion kinase autophosphorylated at the tyrosine residue (pFAK) at 1 h culture was determined using an immunoprecipitation method. Fn adsorbed selectively around the pore edges to form ring-shaped aggregates. The immunostaining results revealed that PAECs adhered to the HC-patterned films at focal contact points localized around pore peripheries. These points correspond to adsorption sites of Fn. The expression of pFAK after 1 h on the HC-patterned film was 3 times higher than that on a corresponding flat film, indicating that the signaling mediated by the binding between Fn and the integrin receptor was more highly activated on the HC-patterned film. These results suggest that the cellular response to HC-patterned films (e.g., adhesion pattern and phosphorylation of FAK) originates from the regularly aligned adsorption pattern of Fn determined by the pore structure of the film..
389. Etsuko Hirota, Masaru Tanaka, Akira Mochizuki, Relationship between blood compatibility and water structure - Comparative study between 2-methoxyethylacrylate- and 2-methoxyethylmethacrylate-based random copolymers, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.31113, 81, 3, 710-719, 2007.06, We have proposed that the excellent blood compatibility of poly(2-methoxyethylacrylate (MEA)) is caused by freezing bound water contained in it on the basis of results on platelet activation (Tanaka and Mochizuki, J Biomed Mater Res A 2004; 68:684-695). To clarify the applicability of this mechanism to other indexes for blood compatibility, the relationship between complement activation and water structure was investigated by using two copolymers, poly(MEA-2-hydroxyethylmethacrylate (HEMA)) and poly(2- methoxyethylmethacrylate (MEMA)-HEMA), where HEMA content was varied from 25 to 90 mol %. ESCA analysis revealed that the surface compositions of these copolymers (dry state) agreed with the compositions determined by 1H NMR. However, analysis by water contact angle (wet state) showed that their surfaces were quite different. The contact angle of poly(MEMA-HEMA) depended on the monomer composition, whereas the angle of poly(MEA-HEMA) was close to that of polyHEMA regardless of the monomer composition. The effect of HEMA content in the copolymers on complement activation (production of C3a) was investigated in an in vitro test. The activation by poly(MEMA-HEMA) was enhanced according to the HEMA content, while the activation by poly(MEA-HEMA) with 0-40 mol % of HEMA was weak and did not depend on the HEMA content. These properties are discussed from the viewpoints of the water structure observed by DSC and the surface structure..
390. Etsuko Hirota, Masaru Tanaka, Akira Mochizuki, Relationship between blood compatibility and water structure - Comparative study between 2-methoxyethylacrylate- and 2-methoxyethylmethacrylate-based random copolymers, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.31113, 81, 3, 710-719, 2007.06, We have proposed that the excellent blood compatibility of poly(2-methoxyethylacrylate (MEA)) is caused by freezing bound water contained in it on the basis of results on platelet activation (Tanaka and Mochizuki, J Biomed Mater Res A 2004; 68:684-695). To clarify the applicability of this mechanism to other indexes for blood compatibility, the relationship between complement activation and water structure was investigated by using two copolymers, poly(MEA-2-hydroxyethylmethacrylate (HEMA)) and poly(2- methoxyethylmethacrylate (MEMA)-HEMA), where HEMA content was varied from 25 to 90 mol %. ESCA analysis revealed that the surface compositions of these copolymers (dry state) agreed with the compositions determined by 1H NMR. However, analysis by water contact angle (wet state) showed that their surfaces were quite different. The contact angle of poly(MEMA-HEMA) depended on the monomer composition, whereas the angle of poly(MEA-HEMA) was close to that of polyHEMA regardless of the monomer composition. The effect of HEMA content in the copolymers on complement activation (production of C3a) was investigated in an in vitro test. The activation by poly(MEMA-HEMA) was enhanced according to the HEMA content, while the activation by poly(MEA-HEMA) with 0-40 mol % of HEMA was weak and did not depend on the HEMA content. These properties are discussed from the viewpoints of the water structure observed by DSC and the surface structure..
391. Etsuko Hirota, Masaru Tanaka, Akira Mochizuki, Relationship between blood compatibility and water structure - Comparative study between 2-methoxyethylacrylate- and 2-methoxyethylmethacrylate-based random copolymers, JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 10.1002/jbm.a.31113, 81A, 3, 710-719, 2007.06, We have proposed that the excellent blood compatibility of poly(2-methoxyethylacrylate (MEA)) is caused by freezing bound water contained in it on the basis of results on platelet activation (Tanaka and Mochizuki, J Biomed Mater Res A 2004; 68:684-695). To clarify the applicability of this mechanism to other indexes for blood compatibility, the relationship between complement activation and water structure was investigated by using two copolymers, poly(MEA-2-hydroxyethylmethacrylate (HEMA)) and poly(2-methoxyethylmethacrylate (MEMA)-HEMA), where HEMA content was varied from 25 to 90 mol %. ESCA analysis revealed that the surface compositions of these copolymers (dry state) agreed with the compositions determined by H-1 NMR. However, analysis by water contact angle (wet state) showed that their surfaces were quite different. The contact angle of poly(MEMA-HEMA) depended on the monomer composition, whereas the angle of poly(MEA-HEMA) was close to that of polyHEMA regardless of the monomer composition. The effect of HEMA content in the copolymers on complement activation (production of C3a) was investigated in an in vitro test. The activation by poly(MEMA-HEMA) was enhanced according to the HEMA content, while the activation by poly(MEA-HEMA) with 0-40 mol % of HEMA was weak and did not depend on the HEMA content. These properties are discussed from the viewpoints of the water structure observed by DSC and the surface structure. (C) 2007 Wiley Periodicals, Inc. J Biomed Mater Res 81A: 710-719, 2007..
392. Yasumitsu Uraki, Junji Nemoto, Hiroyuki Otsuka, Yutaka Tamai, Junji Sugiyama, Takao Kishimoto, Makoto Ubukata, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Honeycomb-like architecture produced by living bacteria, Gluconacetobacter xylinus, Carbohydrate Polymers, 10.1016/j.carbpol.2006.08.021, 69, 1, 1-6, 2007.05, Bacterial cellulose (BC)-producing bacterium, Gluconacetobacter xylinus (ATCC53582), was found to move along linear microgrooves of a stripe-patterned cellulosic scaffold. On the basis of this finding, fabrication of honeycomb-patterned BC was attempted by controlling the bacterial movement using a agarose film scaffold with honeycomb-patterned grooves (concave type). The patterned agarose film was prepared by three steps. The first was transcription of a honeycomb-patterned polycaprolactone film template with polydimethyl siloxane. When the bacteria were cultured on the scaffold under atmospheric conditions, only bacterial proliferation was observed. Honeycomb-patterned BC was obtained when cultured under a humid CO2 atmosphere. Electron diffraction and polarized microscopic observation showed that the patterned BC comprised of the well defined cellulose Iα microfibrils. As another attempt to fabricate honeycomb-patterned BC, the bacteria were cultured on the patterned cellulose and agarose film with convex type of honeycomb. This culture yielded no honeycomb-patterned BC. Therefore, concave type honeycomb scaffold is more suitable to fabricate honeycomb-patterned BC..
393. Yasumitsu Uraki, Junji Nemoto, Hiroyuki Otsuka, Yutaka Tamai, Junji Sugiyama, Takao Kishimoto, Makoto Ubukata, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Honeycomb-like architecture produced by living bacteria, Gluconacetobacter xylinus, Carbohydrate Polymers, 10.1016/j.carbpol.2006.08.021, 69, 1, 1-6, 2007.05, Bacterial cellulose (BC)-producing bacterium, Gluconacetobacter xylinus (ATCC53582), was found to move along linear microgrooves of a stripe-patterned cellulosic scaffold. On the basis of this finding, fabrication of honeycomb-patterned BC was attempted by controlling the bacterial movement using a agarose film scaffold with honeycomb-patterned grooves (concave type). The patterned agarose film was prepared by three steps. The first was transcription of a honeycomb-patterned polycaprolactone film template with polydimethyl siloxane. When the bacteria were cultured on the scaffold under atmospheric conditions, only bacterial proliferation was observed. Honeycomb-patterned BC was obtained when cultured under a humid CO2 atmosphere. Electron diffraction and polarized microscopic observation showed that the patterned BC comprised of the well defined cellulose Iα microfibrils. As another attempt to fabricate honeycomb-patterned BC, the bacteria were cultured on the patterned cellulose and agarose film with convex type of honeycomb. This culture yielded no honeycomb-patterned BC. Therefore, concave type honeycomb scaffold is more suitable to fabricate honeycomb-patterned BC..
394. Yong Mei Chen, Masaru Tanaka, Jian Ping Gong, Kazunori Yasuda, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Platelet adhesion to human umbilical vein endothelial cells cultured on anionic hydrogel scaffolds, Biomaterials, 10.1016/j.biomaterials.2006.12.005, 28, 10, 1752-1760, 2007.04, In this work we describe experiments designed to understand the human platelet adhesion to human umbilical vein endothelial cells (HUVECs) cultured on various kinds of chemically cross-linked anionic hydrogels, which were synthesized by radical polymerization. HUVECs could proliferate to sub-confluent or confluent on poly(acrylic acid) (PAA), poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS), and poly(sodium p-styrene sulfonate) (PNaSS) gels. The proliferation behavior was not sensitive to the cross-linker concentration of the gels. However, the platelet adhesion on the HUVECs cultured on these gels showed different behavior, as revealed by human platelet adhesion test in static conditions. Only a few platelets adhered on the HUVEC sheets cultured on PNaAMPS gels with 4 and 10 mol% cross-linker concentrations, and completely no platelet adhered on the HUVEC sheets cultured on PNaSS gels with 4 and 10 mol% cross-linker concentrations. On the other hand, a large number of platelets adhered on the HUVECs cultured on PAA gels with 1, 2 mol% cross-linker concentrations and PNaAMPS gel with 2 mol% cross-linker concentration. Furthermore, the study showed that promote of the glycocalyx of HUVECs with transforming growth factor-β1 (TGF-β1) decreased platelet adhesion, and degrade the glycocalyx with heparinase I increased platelet adhesion. The results suggested that the glycocalyx of cultured HUVECs modulates platelet compatibility, and the amount of glycocalyx secreted by HUVECs dependents on the chemical structure and cross-linker concentration of gel scaffolds. This result should be applied to make the hybrid artificial blood vessel composes of gels and endothelial cells with high platelet compatibility..
395. James R. McMillan, Masashi Akiyama, Masaru Tanaka, Sadaki Yamamoto, Maki Goto, Riichiro Abe, Daisuke Sawamura, Masatsugu Shimomura, Hiroshi Shimizu, Small-diameter porous poly (ε-caprolactone) films enhance adhesion and growth of human cultured epidermal keratinocyte and dermal fibroblast cells, Tissue Engineering, 10.1089/ten.2006.0321, 13, 4, 789-798, 2007.04, Autologous keratinocyte grafts provide clinical benefit by rapidly covering wounded areas, but they are fragile. We therefore developed hiocompatihle hexagonal-packed porous films with uniform, circular pore sizes to support human keratinocytes and fibroblasts. Cells were cultured on these porous poly (ε-calprolactone) films with pore sizes ranging from novel ultra-small 3 μm to 20 μm. These were compared with flat (pore-less) films. Cell growth rates, adhesion, migration, and ultrastructural morphology were examined. Human keratinocytes and fibroblasts attached to all films. Furthermore, small-pore (3-5 μm) films showed the highest levels of cell adhesion and survival and prevented migration into the pores and opposing film surface. Keratinocyte migration over small-pore film surface was inhibited. Keratinocytes optimally attached to 3-μm-pore films due to a combination of greater pore numbers (porosity), a greater circumference of the pore edge per unit surface area, and greater frequency of flat surface areas for attachment, allowing better cell-substrate and cell-cell attachment and growth. The 3-μm pore size allowed cell-cell communication, together with diffusion of soluble nutrients and factors from the culture medium or wound substrate. These characteristics are considered important in developing grafts for use in the treatment of human skin wounds..
396. Yong Mei Chen, Masaru Tanaka, Jian Ping Gong, Kazunori Yasuda, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Platelet adhesion to human umbilical vein endothelial cells cultured on anionic hydrogel scaffolds, Biomaterials, 10.1016/j.biomaterials.2006.12.005, 28, 10, 1752-1760, 2007.04, In this work we describe experiments designed to understand the human platelet adhesion to human umbilical vein endothelial cells (HUVECs) cultured on various kinds of chemically cross-linked anionic hydrogels, which were synthesized by radical polymerization. HUVECs could proliferate to sub-confluent or confluent on poly(acrylic acid) (PAA), poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS), and poly(sodium p-styrene sulfonate) (PNaSS) gels. The proliferation behavior was not sensitive to the cross-linker concentration of the gels. However, the platelet adhesion on the HUVECs cultured on these gels showed different behavior, as revealed by human platelet adhesion test in static conditions. Only a few platelets adhered on the HUVEC sheets cultured on PNaAMPS gels with 4 and 10 mol% cross-linker concentrations, and completely no platelet adhered on the HUVEC sheets cultured on PNaSS gels with 4 and 10 mol% cross-linker concentrations. On the other hand, a large number of platelets adhered on the HUVECs cultured on PAA gels with 1, 2 mol% cross-linker concentrations and PNaAMPS gel with 2 mol% cross-linker concentration. Furthermore, the study showed that promote of the glycocalyx of HUVECs with transforming growth factor-β1 (TGF-β1) decreased platelet adhesion, and degrade the glycocalyx with heparinase I increased platelet adhesion. The results suggested that the glycocalyx of cultured HUVECs modulates platelet compatibility, and the amount of glycocalyx secreted by HUVECs dependents on the chemical structure and cross-linker concentration of gel scaffolds. This result should be applied to make the hybrid artificial blood vessel composes of gels and endothelial cells with high platelet compatibility..
397. James R. McMillan, Masashi Akiyama, Masaru Tanaka, Sadaki Yamamoto, Maki Goto, Riichiro Abe, Daisuke Sawamura, Masatsugu Shimomura, Hiroshi Shimizu, Small-diameter porous poly (ε-caprolactone) films enhance adhesion and growth of human cultured epidermal keratinocyte and dermal fibroblast cells, Tissue Engineering, 10.1089/ten.2006.0321, 13, 4, 789-798, 2007.04, Autologous keratinocyte grafts provide clinical benefit by rapidly covering wounded areas, but they are fragile. We therefore developed hiocompatihle hexagonal-packed porous films with uniform, circular pore sizes to support human keratinocytes and fibroblasts. Cells were cultured on these porous poly (ε-calprolactone) films with pore sizes ranging from novel ultra-small 3 μm to 20 μm. These were compared with flat (pore-less) films. Cell growth rates, adhesion, migration, and ultrastructural morphology were examined. Human keratinocytes and fibroblasts attached to all films. Furthermore, small-pore (3-5 μm) films showed the highest levels of cell adhesion and survival and prevented migration into the pores and opposing film surface. Keratinocyte migration over small-pore film surface was inhibited. Keratinocytes optimally attached to 3-μm-pore films due to a combination of greater pore numbers (porosity), a greater circumference of the pore edge per unit surface area, and greater frequency of flat surface areas for attachment, allowing better cell-substrate and cell-cell attachment and growth. The 3-μm pore size allowed cell-cell communication, together with diffusion of soluble nutrients and factors from the culture medium or wound substrate. These characteristics are considered important in developing grafts for use in the treatment of human skin wounds..
398. Masaru Tanaka, Aiko Takayama, Emiko Ito, Hiroshi Sunami, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of pore size of self-organized honeycomb-patterned polymer films on spreading, focal adhesion, proliferation, and function of endothelial cells, Journal of Nanoscience and Nanotechnology, 10.1166/jnn.2007.514, 7, 3, 763-772, 2007.03, The design of nano- and microstructures based on self-organization is a key area of research in the search for new materials, and it has a variety of potential applications in tissue engineering scaffolds. We have reported a honeycomb-patterned polymer film (honeycomb film) with highly regular pores that is formed by self-organization. This study describes the behavior of vascular endothelial cells (ECs) on honeycomb films with four different pore sizes (5, 9, 12, and 16 μm) as well as on a flat film. We examined the influence of the honeycomb pattern and pore size on cell behavior. The changes in cell morphologies, actin filaments, vinculin clusters, cell proliferation, and secreted extracellular matrix (ECM) (fibronectin, laminin, type IV collagen, and elastin) production profiles were observed by using optical, fluorescence, and scanning electron microscopy. The ECs that adhered to the flat film showed an elongated morphology with random orientation; the actin filaments and focal adhesions were not conspicuous. On the other hand, the ECs on the honeycomb films exhibited greater spreading and flattening; the degree of spreading of the ECs increased with an increase in the pore size. The actin filaments and focal adhesions appeared conspicuous, and the focal adhesions localized along the edge of the honeycomb pores were distributed over the entire projected cell area. The honeycomb film with a pore size of 5 μm showed the highest cell proliferation and ECM production profiles. These results suggest that the honeycomb film is a suitable material for designing a new vascular device..
399. Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Time-resolved in situ ATR-IR observations of the process of sorption of water into a poly(2-methoxyethyl acrylate) film, Langmuir, 10.1021/la0625998, 23, 7, 3750-3761, 2007.03, A process of water sorption into a biocompatible polymer, poly (2-methoxyethyl acrylate) (PMEA), was investigated by time-resolved, in situ, attenuated total reflection infrared spectroscopy. Evidence for three different types of hydrated water in PMEA, that is, nonfreezing water, freezing bound water, and freezing water, were found. Each hydration structure was elucidated at the functional group level. Nonfreezing water, which never crystallizes, even at -100 °C, has a C=O⋯H-O type of hydrogen bonding interaction with the carbonyl group of PMEA. Freezing bound water, which crystallizes in a heating process below 0 °C, interacts with the methoxy moiety in the PMEA side chain terminal. Freezing water, which crystallizes -0 °C, has bulk-water-like structure with an O-H⋯O-H hydrogen bonds network. It has been concluded from the present study that the methoxy moiety in the PMEA side chain terminal plays an important role for the excellent biocompatibility of PMEA..
400. Masaru Tanaka, Aiko Takayama, Emiko Ito, Hiroshi Sunami, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of pore size of self-organized honeycomb-patterned polymer films on spreading, focal adhesion, proliferation, and function of endothelial cells, Journal of nanoscience and nanotechnology, 10.1166/jnn.2007.514, 7, 3, 763-772, 2007.03, The design of nano- and microstructures based on self-organization is a key area of research in the search for new materials, and it has a variety of potential applications in tissue engineering scaffolds. We have reported a honeycomb-patterned polymer film (honeycomb film) with highly regular pores that is formed by self-organization. This study describes the behavior of vascular endothelial cells (ECs) on honeycomb films with four different pore sizes (5, 9, 12, and 16 μm) as well as on a flat film. We examined the influence of the honeycomb pattern and pore size on cell behavior. The changes in cell morphologies, actin filaments, vinculin clusters, cell proliferation, and secreted extracellular matrix (ECM) (fibronectin, laminin, type IV collagen, and elastin) production profiles were observed by using optical, fluorescence, and scanning electron microscopy. The ECs that adhered to the flat film showed an elongated morphology with random orientation; the actin filaments and focal adhesions were not conspicuous. On the other hand, the ECs on the honeycomb films exhibited greater spreading and flattening; the degree of spreading of the ECs increased with an increase in the pore size. The actin filaments and focal adhesions appeared conspicuous, and the focal adhesions localized along the edge of the honeycomb pores were distributed over the entire projected cell area. The honeycomb film with a pore size of 5 μm showed the highest cell proliferation and ECM production profiles. These results suggest that the honeycomb film is a suitable material for designing a new vascular device..
401. Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Time-resolved in situ ATR-IR observations of the process of sorption of water into a poly(2-methoxyethyl acrylate) film, Langmuir, 10.1021/la0625998, 23, 7, 3750-3761, 2007.03, A process of water sorption into a biocompatible polymer, poly (2-methoxyethyl acrylate) (PMEA), was investigated by time-resolved, in situ, attenuated total reflection infrared spectroscopy. Evidence for three different types of hydrated water in PMEA, that is, nonfreezing water, freezing bound water, and freezing water, were found. Each hydration structure was elucidated at the functional group level. Nonfreezing water, which never crystallizes, even at -100 °C, has a C=O⋯H-O type of hydrogen bonding interaction with the carbonyl group of PMEA. Freezing bound water, which crystallizes in a heating process below 0 °C, interacts with the methoxy moiety in the PMEA side chain terminal. Freezing water, which crystallizes -0 °C, has bulk-water-like structure with an O-H⋯O-H hydrogen bonds network. It has been concluded from the present study that the methoxy moiety in the PMEA side chain terminal plays an important role for the excellent biocompatibility of PMEA..
402. T. Okajima, Masaru Tanaka, S. Tsukiyama, T. Kadowaki, S. Yamamoto, M. Shimomura, H. Tokumoto, Stress relaxation of HepG2 cells measured by atomic force microscopy, Nanotechnology, 10.1088/0957-4484/18/8/084010, 18, 8, 2007.02, Stress relaxation of HepG2 cells was examined with an atomic force microscope (AFM). In the measurement, a loading force was applied to the cell by an AFM tip, and a time series of the cantilever deflection signal was measured at a fixed position of the cantilever base displacement. The relaxation of the loading force was clearly observed on the HepG2 cells, and was well fitted to a stretched exponential function known as the Kohlrausch-Williams-Watts (KWW) function, which is empirically employed to represent dispersion processes of the system. The relaxation time and the stretching exponent parameter were estimated to be ∼0.5 s and 0.4-0.6, respectively. The latter indicated that the relaxation observed in HepG2 cells consisted of multiple relaxation processes. Moreover, it was found that the characteristic feature of the relaxation process was not strongly correlated with the elastic properties of the cells..
403. T. Okajima, M. Tanaka, S. Tsukiyama, T. Kadowaki, S. Yamamoto, M. Shimomura, H. Tokumoto, Stress relaxation of HepG2 cells measured by atomic force microscopy, Nanotechnology, 10.1088/0957-4484/18/8/084010, 18, 8, 2007.02, Stress relaxation of HepG2 cells was examined with an atomic force microscope (AFM). In the measurement, a loading force was applied to the cell by an AFM tip, and a time series of the cantilever deflection signal was measured at a fixed position of the cantilever base displacement. The relaxation of the loading force was clearly observed on the HepG2 cells, and was well fitted to a stretched exponential function known as the Kohlrausch-Williams-Watts (KWW) function, which is empirically employed to represent dispersion processes of the system. The relaxation time and the stretching exponent parameter were estimated to be ∼0.5 s and 0.4-0.6, respectively. The latter indicated that the relaxation observed in HepG2 cells consisted of multiple relaxation processes. Moreover, it was found that the characteristic feature of the relaxation process was not strongly correlated with the elastic properties of the cells..
404. Akinori Tsuruma, Masaru Tanaka, Sada Aki Yamamoto, Masatsugu Shimomura, Suppression of neural stem cell differentiation by Honeycomb-patterned films, 10th World Congress on Medical Physics and Biomedical Engineering, WC 2006 IFMBE Proceedings, 14, 1, 3558-3561, 2007.01, Neural stem cells (NSCs) play important roles in brain development. NSCs have self-renewal potency and can differentiate into phenotypes of neural cells (neuron, astrocyte and oligodendrocyte). Recently, NSCs are expected for regenerative medicine to be transplanted into damaged neural tissues. For this purpose, it is important to maintain these properties of NSCs in culture. Nano-micro patterns on the surface of scaffold have significant influences on the cell morphologies, proliferation, differentiation and function. In previous study, we prepared highly regular porous films (honeycomb-patterned films) by a casting technique, and investigated neural cell morphologies on flat film and honeycomb-patterned films. As a result, morphologies of adhered neural cells were changed by varying pore size of the honeycomb-patterned films. Especially, we found that cell aggregates were formed on the patterned films of pore size 3 m. Our current study showed that NSCs were suppressed its differentiation into neurons on the patterned films of pore size 3 μm. This result indicate that NSCs are positively regulated their own survival and differentiation. To use neural stem cells / progenitor cells for regenerative medicine, we need environments where these NSCs can live in vitro without losing their ability to proliferation and differentiation..
405. Akinori Tsuruma, Masaru Tanaka, Sada Aki Yamamoto, Masatsugu Shimomura, Suppression of neural stem cell differentiation by Honeycomb-patterned films, 10th World Congress on Medical Physics and Biomedical Engineering, WC 2006 IFMBE Proceedings, 14, 1, 3558-3561, 2007.01, Neural stem cells (NSCs) play important roles in brain development. NSCs have self-renewal potency and can differentiate into phenotypes of neural cells (neuron, astrocyte and oligodendrocyte). Recently, NSCs are expected for regenerative medicine to be transplanted into damaged neural tissues. For this purpose, it is important to maintain these properties of NSCs in culture. Nano-micro patterns on the surface of scaffold have significant influences on the cell morphologies, proliferation, differentiation and function. In previous study, we prepared highly regular porous films (honeycomb-patterned films) by a casting technique, and investigated neural cell morphologies on flat film and honeycomb-patterned films. As a result, morphologies of adhered neural cells were changed by varying pore size of the honeycomb-patterned films. Especially, we found that cell aggregates were formed on the patterned films of pore size 3 m. Our current study showed that NSCs were suppressed its differentiation into neurons on the patterned films of pore size 3 μm. This result indicate that NSCs are positively regulated their own survival and differentiation. To use neural stem cells / progenitor cells for regenerative medicine, we need environments where these NSCs can live in vitro without losing their ability to proliferation and differentiation..
406. Tomohiro Hayashi, Masaru Tanaka, Direct observation of biocompatibility of PMEA(poly(2-methoxyethyl acrylate)) using Atomic Force Microscop, Biointerphases, 2, 119, 2007.
407. Sadaaki Yamamoto, Masaru Tanaka, The influence of pore size of a honeycomb film on early spreading process of endtherial cells, J. Surf. Sci. Soc. Jap, 28, 8, 433, 2007.
408. Tomohiro Hayashi, Masaru Tanaka, Direct observation of biocompatibility of PMEA(poly(2-methoxyethyl acrylate)) using Atomic Force Microscop, Biointerphases, 2, 119, 2007.
409. Sadaaki Yamamoto, Masaru Tanaka, The influence of pore size of a honeycomb film on early spreading process of endtherial cells, J. Surf. Sci. Soc. Jap, 28, 8, 433, 2007.
410. Hiroyuki Ishida, Yuko Miwa, Akira Mochizuki, Masaru Tanaka, Study on structure of water in membranes of PMEA and PHEMA by 2H-NMR, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4375-4376, 2006.12, The states of water in membranes of PMEA and PHEMA were studied with solution 2H-NMR method. The membranes were prepared by spin-coating on PET film. In order to investigate the change in the behavior of water with time after adding of H2O in membranes of PMEA and PHEMA, 2H-NMR measurements were carried out. From the results of the time dependence spectra and spin-lattice relaxation time T1, the followings were concluded. The mobility of water molecule in the PMEA membrane after H2O addition was higher than that in the PHEMA membrane, while exchange rates of the water between inside and outside of the PMEA membrane were slower than those of the PHEMA membrane. The state of water structure in the PMEA membrane is more stable than that in the PHEMA membrane..
411. Yuko Miwa, Hiroyuki Ishida, Akira Mochizuki, Masaru Tanaka, Study on structure of water in PMEA and PHEMA and there copolymers by 2H solid-state NMR, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 2006.10, The states of water in PMEA and PHEMA were studied by using solid-state 2H-NMR. In order to investigate the behavior of water in PMEA, PHEMA, and their coploymeres, the temperature dependence (from -60 °C to 37°C) of 2H-NMR spectra and relaxation times were observed for the polymers with various contents of water. From the results of T1 the followings are concluded. The mobility of water molecule is high and hardly influenced by the water content in PMEA, while it depends strongly on the water content in PHEMA. In the range under 20% of the water content, the water in PHEMA is strongly bounded to the polymer..
412. Sadaaki Yamamoto, Masaru Tanaka, Hiroshi Sunami, Keiko Arai, Aiko Takayama, Shigeko Yamashita, Yuka Morita, Masatsugu Shimomura, Relationship between adsorbed fibronectin and cell adhesion on a honeycomb-patterned film, Surface Science, 10.1016/j.susc.2006.01.085, 600, 18, 3785-3791, 2006.09, Substratum surface morphology plays a vital roles in cellular behavior. Here, we characterized adsorption of fibronectin (Fn) as a typical cell adhesion protein onto honeycomb-patterned films made of poly(ε-caprolactone) (PCL) by using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). In order to determine how cells adhere to a honeycomb-patterned film, focal adhesion of cardiac myocytes (CMYs) and endothelial cells (ECs) on the films were studied by using fluorescence labeling of vinculin. Fn adsorbs around the pore edges to form ring-shaped structures. CMYs and ECs adhere onto the honeycomb-patterned films at focal contact points localized around pore edges distributed over the entire cellular surface. The focal contact points on the honeycomb-patterned films correspond well with the adsorption sites of Fn. We suggest that the cell response to honeycomb-patterned films is associated with the adsorption pattern of Fn on the film..
413. Sadaaki Yamamoto, Masaru Tanaka, Hiroshi Sunami, Keiko Arai, Aiko Takayama, Shigeko Yamashita, Yuka Morita, Masatsugu Shimomura, Relationship between adsorbed fibronectin and cell adhesion on a honeycomb-patterned film, Surface Science, 10.1016/j.susc.2006.01.085, 600, 18, 3785-3791, 2006.09, Substratum surface morphology plays a vital roles in cellular behavior. Here, we characterized adsorption of fibronectin (Fn) as a typical cell adhesion protein onto honeycomb-patterned films made of poly(ε-caprolactone) (PCL) by using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). In order to determine how cells adhere to a honeycomb-patterned film, focal adhesion of cardiac myocytes (CMYs) and endothelial cells (ECs) on the films were studied by using fluorescence labeling of vinculin. Fn adsorbs around the pore edges to form ring-shaped structures. CMYs and ECs adhere onto the honeycomb-patterned films at focal contact points localized around pore edges distributed over the entire cellular surface. The focal contact points on the honeycomb-patterned films correspond well with the adsorption sites of Fn. We suggest that the cell response to honeycomb-patterned films is associated with the adsorption pattern of Fn on the film..
414. Masaru Tanaka, Kazutaka Nishikawa, Hisashi Okubo, Hirofumi Kamachi, Tomoaki Kawai, Michiaki Matsushita, Satoru Todo, Masatsugu Shimomura, Control of hepatocyte adhesion and function on self-organized honeycomb-patterned polymer film, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2005.11.098, 284-285, 464-469, 2006.08, Hepatocytes were cultured on a honeycomb-patterned polymer film (honeycomb film) formed by self-organization in order to investigate the influence of the honeycomb pattern on cell behavior. The changes in cell morphologies and actin filaments were observed by optical, fluorescence, and scanning electron microscopy. Hepatocytes were flattened, and the actin filaments appeared conspicuously in the spreading regions on a flat film. In contrast, the hepatocytes that were cultured on the honeycomb film were observed to form a spherical shape, and the actin filaments were localized inside the edge of the spheroid. The spheroids were observed within several hours after seeding on the honeycomb film; they were attached and the spheroid shape was maintained without any deformation. The spheroids expressed a higher level of liver specific function than the cell monolayers on the flat film. These results suggest that the honeycomb film is a suitable material for tissue engineering scaffolds and biomedical devices..
415. Hiroshi Sunami, Emiko Ito, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of honeycomb film on protein adsorption, cell adhesion and proliferation, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2005.11.041, 284-285, 548-551, 2006.08, This article describes novel methods for controlling of cell adhesion by using micro porous polymer films. Recently we found the highly ordered micro porous films were formed when poly(ε-caprolactone) (PCL) solution was cast on substrates at high atmospheric humidity. The micro porous film has regular honeycomb morphology with a size of 5 μm per cell (honeycomb film). Endothelial cells grew rapidly on the honeycomb film. After 24 h cell culture, the cell number on honeycomb films was lager than that on PCL flat films. In order to elucidate the effect of honeycomb films as a scaffold for cell culture, the adsorbed proteins on honeycomb films under cell culture condition were observed. After conditioning of the honeycomb film and the flat film in DMEM containing 10% foetal bovine serum (FBS) for 72 h at 37 °C in 5% CO2 atmosphere, the adsorbed fibronectin-FITC and albumin-Texasred on the honeycomb films was observed by using confocal laser scanning microscope (CLSM). The observation revealed that fibronectin showed site-selective adsorption behavior on the honeycomb film. Albumin adsorbed on the honeycomb film non site-selectively, while fibronectin mainly adsorbed on inside of honeycomb pores. On the flat film, fibronectin was hardly observed. Since the honeycomb film accelerate the adsorption of fibronectin which is a typical protein as a cell adhesion molecule, the film could be a scaffold with excellent cell adhesion properties..
416. Akinori Tsuruma, Masaru Tanaka, Sadaaki Yamamoto, Nobuyuki Fukushima, Hiroshi Yabu, Masatsugu Shimomura, Topographical control of neurite extension on stripe-patterned polymer films, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2005.11.100, 284-285, 470-474, 2006.08, Controlling cell responses to material surfaces is important for tissue engineering. Topographical property on material surfaces can play a crucial role in directing nerve regeneration. We prepared regular stripe-patterned (groove-ridge pattern) polymer film by self-organization in order to control direction of neurite extension. Neural cells from cerebral cortex of embryonic day-14 mice were cultured on the film coated with poly-l-lysine. Here, we describe a complex and unusual contact guidance dependent on the pattern feature size. The neurites grew perpendicular to wide groove of 12.7 μm and wide ridge of 4.3 μm but parallel to narrow grooves (6.1 and 8.4 μm) and narrow ridge (2.2 and 3.6 μm). The neurites sprouted parallel to the narrow groove but uniformly on the wide groove. The emersion of neurites was suppressed and the length of neurites was longer compared with on a flat film. These results are of interest to understanding contact guidance and designing scaffold for neural network formation..
417. Masaru Tanaka, Kazutaka Nishikawa, Hisashi Okubo, Hirofumi Kamachi, Tomoaki Kawai, Michiaki Matsushita, Satoru Todo, Masatsugu Shimomura, Control of hepatocyte adhesion and function on self-organized honeycomb-patterned polymer film, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2005.11.098, 284-285, 464-469, 2006.08, Hepatocytes were cultured on a honeycomb-patterned polymer film (honeycomb film) formed by self-organization in order to investigate the influence of the honeycomb pattern on cell behavior. The changes in cell morphologies and actin filaments were observed by optical, fluorescence, and scanning electron microscopy. Hepatocytes were flattened, and the actin filaments appeared conspicuously in the spreading regions on a flat film. In contrast, the hepatocytes that were cultured on the honeycomb film were observed to form a spherical shape, and the actin filaments were localized inside the edge of the spheroid. The spheroids were observed within several hours after seeding on the honeycomb film; they were attached and the spheroid shape was maintained without any deformation. The spheroids expressed a higher level of liver specific function than the cell monolayers on the flat film. These results suggest that the honeycomb film is a suitable material for tissue engineering scaffolds and biomedical devices..
418. Hiroshi Sunami, Emiko Ito, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Effect of honeycomb film on protein adsorption, cell adhesion and proliferation, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2005.11.041, 284-285, 548-551, 2006.08, This article describes novel methods for controlling of cell adhesion by using micro porous polymer films. Recently we found the highly ordered micro porous films were formed when poly(ε-caprolactone) (PCL) solution was cast on substrates at high atmospheric humidity. The micro porous film has regular honeycomb morphology with a size of 5 μm per cell (honeycomb film). Endothelial cells grew rapidly on the honeycomb film. After 24 h cell culture, the cell number on honeycomb films was lager than that on PCL flat films. In order to elucidate the effect of honeycomb films as a scaffold for cell culture, the adsorbed proteins on honeycomb films under cell culture condition were observed. After conditioning of the honeycomb film and the flat film in DMEM containing 10% foetal bovine serum (FBS) for 72 h at 37 °C in 5% CO2 atmosphere, the adsorbed fibronectin-FITC and albumin-Texasred on the honeycomb films was observed by using confocal laser scanning microscope (CLSM). The observation revealed that fibronectin showed site-selective adsorption behavior on the honeycomb film. Albumin adsorbed on the honeycomb film non site-selectively, while fibronectin mainly adsorbed on inside of honeycomb pores. On the flat film, fibronectin was hardly observed. Since the honeycomb film accelerate the adsorption of fibronectin which is a typical protein as a cell adhesion molecule, the film could be a scaffold with excellent cell adhesion properties..
419. Akinori Tsuruma, Masaru Tanaka, Sadaaki Yamamoto, Nobuyuki Fukushima, Hiroshi Yabu, Masatsugu Shimomura, Topographical control of neurite extension on stripe-patterned polymer films, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/j.colsurfa.2005.11.100, 284-285, 470-474, 2006.08, Controlling cell responses to material surfaces is important for tissue engineering. Topographical property on material surfaces can play a crucial role in directing nerve regeneration. We prepared regular stripe-patterned (groove-ridge pattern) polymer film by self-organization in order to control direction of neurite extension. Neural cells from cerebral cortex of embryonic day-14 mice were cultured on the film coated with poly-l-lysine. Here, we describe a complex and unusual contact guidance dependent on the pattern feature size. The neurites grew perpendicular to wide groove of 12.7 μm and wide ridge of 4.3 μm but parallel to narrow grooves (6.1 and 8.4 μm) and narrow ridge (2.2 and 3.6 μm). The neurites sprouted parallel to the narrow groove but uniformly on the wide groove. The emersion of neurites was suppressed and the length of neurites was longer compared with on a flat film. These results are of interest to understanding contact guidance and designing scaffold for neural network formation..
420. Yukako Fukuhira, Eiichi Kitazono, Takami Hayashi, Hiroaki Kaneko, Masaru Tanaka, Masatsugu Shimomura, Yoshihiko Sumi, Biodegradable honeycomb-patterned film composed of poly(lactic acid) and dioleoylphosphatidylethanolamine, Biomaterials, 10.1016/j.biomaterials.2005.10.019, 27, 9, 1797-1802, 2006.03, Honeycomb-patterned films have been reported to be useful for scaffolds of cell culture in tissue engineering. In the present study, we investigated a new compound, dioleoylphosphatidylethanolamine (DOPE), a naturally derived phospholipid having unsaturated fatty acid moieties, as a surfactant for fabricating honeycomb-patterned poly(d,l-lactide) (PLA) film. Only DOPE among commercially available phospholipids was useful as a surfactant, and it showed good solubility in PLA/chloroform solution and an excellent property for fabricating honeycomb-patterned film (the concentration of DOPE was from 0.2% to 20% by weight based on the weight of PLA). The pore size of the honeycomb was uniform, and all pores were interconnected with each other. The contact angle of water on the honeycomb-patterned film was affected by the amount of DOPE. Time-of-flight secondary ion mass spectrometer (TOF-SIMS) data suggested that DOPE was concentrated on the surface of the honeycomb-patterned film. To investigate cell proliferation and adhesion on the honeycomb-patterned film, NIH3T3 fibroblast cells were cultured on the film. The NIH3T3 cells adhered well on the honeycomb-patterned PLA film with DOPE (PLA-DOPE) and showed good cell proliferation compared to that on honeycomb-patterned PLA film fabricated with a copolymer (CAP) of dodecylacrylamide and ω-carboxyhexylacrylamide (PLA-CAP). These results suggest that the honeycomb-patterned PLA-DOPE can be applicable as a scaffold for cells with better profiles in comparison with PLA-CAP..
421. Etsuko Hirota, Koichi Ute, Mitsunari Uehara, Tatsuki Kitayama, Masaru Tanaka, Akira Mochizuki, Study on blood compatibility with poly(2-methoxyethylacrylate) - Relationship between surface structure, water structure, and platelet compatibility in 2-methoxyethylacrylate/2-hydroxyethylmethacrylate diblock copolymer, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.30563, 76, 3, 540-550, 2006.03, Diblock copolymers composed of 2-methoxyethylacrylate (MEA) and 2-hydroxyethylmethacrylate (HEMA) were firstly prepared (the composition ratio = 90/10, 79/21, 66/34, and 48/52 mol/mol) by anion living polymerization. ESCA analysis of their surface structures (dry state) revealed that PMEA segment was segregated to the top surface in all of the polymers, whereas the results of contact angle of water (wet state) showed that the surfaces were covered with PHEMA segment. In vitro platelet adhesion test showed that these polymers had the excellent compatibility with platelet compared to PHEMA homopolymer. Water structure in the hydrated copolymers was investigated by DSC and freezing bound water was observed for all the polymers like PMEA homopolymer, whereas it was not found in PHEMA homopolymer. Further investigation of water structure based on the results of DSC and EWCMS (equilibrium water content by moisture sorption) suggested that freezing bound water existed in PHEMA segment in addition to PMEA segment. We have proposed that the water plays a key role in the appearance of good blood compatibility of the copolymer, according to our previous works (Tanaka et al. Biomacromolecules 2002;3:36-41, Tanaka et al. J Biomed Mater Res A 2004;68:684-695)..
422. Yukako Fukuhira, Eiichi Kitazono, Takami Hayashi, Hiroaki Kaneko, Masaru Tanaka, Masatsugu Shimomura, Yoshihiko Sumi, Biodegradable honeycomb-patterned film composed of poly(lactic acid) and dioleoylphosphatidylethanolamine, Biomaterials, 10.1016/j.biomaterials.2005.10.019, 27, 9, 1797-1802, 2006.03, Honeycomb-patterned films have been reported to be useful for scaffolds of cell culture in tissue engineering. In the present study, we investigated a new compound, dioleoylphosphatidylethanolamine (DOPE), a naturally derived phospholipid having unsaturated fatty acid moieties, as a surfactant for fabricating honeycomb-patterned poly(d,l-lactide) (PLA) film. Only DOPE among commercially available phospholipids was useful as a surfactant, and it showed good solubility in PLA/chloroform solution and an excellent property for fabricating honeycomb-patterned film (the concentration of DOPE was from 0.2% to 20% by weight based on the weight of PLA). The pore size of the honeycomb was uniform, and all pores were interconnected with each other. The contact angle of water on the honeycomb-patterned film was affected by the amount of DOPE. Time-of-flight secondary ion mass spectrometer (TOF-SIMS) data suggested that DOPE was concentrated on the surface of the honeycomb-patterned film. To investigate cell proliferation and adhesion on the honeycomb-patterned film, NIH3T3 fibroblast cells were cultured on the film. The NIH3T3 cells adhered well on the honeycomb-patterned PLA film with DOPE (PLA-DOPE) and showed good cell proliferation compared to that on honeycomb-patterned PLA film fabricated with a copolymer (CAP) of dodecylacrylamide and ω-carboxyhexylacrylamide (PLA-CAP). These results suggest that the honeycomb-patterned PLA-DOPE can be applicable as a scaffold for cells with better profiles in comparison with PLA-CAP..
423. Etsuko Hirota, Koichi Ute, Mitsunari Uehara, Tatsuki Kitayama, Masaru Tanaka, Akira Mochizuki, Study on blood compatibility with poly(2-methoxyethylacrylate) - Relationship between surface structure, water structure, and platelet compatibility in 2-methoxyethylacrylate/2-hydroxyethylmethacrylate diblock copolymer, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.30563, 76, 3, 540-550, 2006.03, Diblock copolymers composed of 2-methoxyethylacrylate (MEA) and 2-hydroxyethylmethacrylate (HEMA) were firstly prepared (the composition ratio = 90/10, 79/21, 66/34, and 48/52 mol/mol) by anion living polymerization. ESCA analysis of their surface structures (dry state) revealed that PMEA segment was segregated to the top surface in all of the polymers, whereas the results of contact angle of water (wet state) showed that the surfaces were covered with PHEMA segment. In vitro platelet adhesion test showed that these polymers had the excellent compatibility with platelet compared to PHEMA homopolymer. Water structure in the hydrated copolymers was investigated by DSC and freezing bound water was observed for all the polymers like PMEA homopolymer, whereas it was not found in PHEMA homopolymer. Further investigation of water structure based on the results of DSC and EWCMS (equilibrium water content by moisture sorption) suggested that freezing bound water existed in PHEMA segment in addition to PMEA segment. We have proposed that the water plays a key role in the appearance of good blood compatibility of the copolymer, according to our previous works (Tanaka et al. Biomacromolecules 2002;3:36-41, Tanaka et al. J Biomed Mater Res A 2004;68:684-695)..
424. Etsuko Hirota, Koichi Ute, Mitsunari Uehara, Tatsuki Kitayama, Masaru Tanaka, Akira Mochizuki, Study on blood compatibility with poly(2-methoxyethylacrylate) - Relationship between surface structure, water structure, and platelet compatibility in 2-methoxyethylacrylate/2-hydroxyethylmethacrylate diblock copolymer, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.30563, 76, 3, 540-550, 2006.03, Diblock copolymers composed of 2-methoxyethylacrylate (MEA) and 2-hydroxyethylmethacrylate (HEMA) were firstly prepared (the composition ratio = 90/10, 79/21, 66/34, and 48/52 mol/mol) by anion living polymerization. ESCA analysis of their surface structures (dry state) revealed that PMEA segment was segregated to the top surface in all of the polymers, whereas the results of contact angle of water (wet state) showed that the surfaces were covered with PHEMA segment. In vitro platelet adhesion test showed that these polymers had the excellent compatibility with platelet compared to PHEMA homopolymer. Water structure in the hydrated copolymers was investigated by DSC and freezing bound water was observed for all the polymers like PMEA homopolymer, whereas it was not found in PHEMA homopolymer. Further investigation of water structure based on the results of DSC and EWCMS (equilibrium water content by moisture sorption) suggested that freezing bound water existed in PHEMA segment in addition to PMEA segment. We have proposed that the water plays a key role in the appearance of good blood compatibility of the copolymer, according to our previous works (Tanaka et al. Biomacromolecules 2002
3:36-41, Tanaka et al. J Biomed Mater Res A 2004
68:684-695). © 2005 Wiley Periodicals, Inc..
425. E Hirota, K Ute, M Uehara, T Kitayama, M Tanaka, A Mochizuki, Study on blood compatibility with poly(2-methoxyethylacrylate)-relationship between surface structure., water structure, and platelet compatibility in 2-methoxyethylacrylate/2hydroxyethylmethacrylate diblock copolymer, JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 10.1002/jbm.a.30563, 76A, 3, 540-550, 2006.03, Diblock copolymers composed of 2-methoxyethylacrylate (MEA) and 2-hydroxyethylmethacrylate (HEMA) were firstly prepared (the composition ratio = 90/10, 79/21, 66/34, and 48/52 mol/mol) by anion living polymerization. ESCA analysis of their surface structures (dry state) revealed that PMEA segment was segregated to the top surface in all of the polymers, whereas the results of contact angle of water (wet state) showed that the surfaces were covered with PHEMA segment. In vitro platelet adhesion test showed that these polymers had the excellent compatibility with platelet compared to PHEMA homopolymer. Water structure in the hydrated copolymers was investigated by DSC and freezing bound water was observed for all the polymers like PMEA homopolymer, whereas it was not found in PHEMA homopolymer. Further investigation of water structure based on the results of DSC and EWCMS (equilibrium water content by moisture sorption) suggested that freezing bound water existed in PHEMA segment in addition to PMEA segment. We have proposed that the water plays a key role in the appearance of good blood compatibility of the copolymer, according to our previous works (Tanaka et al. Biomacromolecules 2002; 3:36-41, Tanaka et al. J Biomed Mater Res A 2004;68:684-695). (C) 2005 Wiley Periodicals, Inc..
426. Sadaaki Yamamot, Masaru Tanaka, Hiroshi Sunami, Yuka Mortta, Emio Ito, Keiko Arai, Shigeko Yamashita, Masatsugu Shimomura, Adhesion and signal transduction of endothelial cells on a honeycomb films pre-coated by fibronectin, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 5493-5494, 2006, In order to determine how cells respond to a honeycomb film of poly(ε-caprolactone) (PCL), focal adhesion of porcine aortic endothelial cells (PAECs) cultured on the Fn coated honeycomb films in a serum free medium were characterized by using immunofluorescencet labeling of vinculin and focal adhesion kinase autophosphorylated at the tyrosine residue 397 (pY397FAK).. The sites of pY397FAK and vinculin were overlapped and agreed well with the adsorption site of Fn fibrils. This demonstrated that PAECs adhered onto the honeycomb films at focal contact points localized around pore periphery. The expression of pY397FAK was 3 times higher than that on a PCL flat film as a reference. These results imply that the signaling mediated by a integrin receptor - Fn binding were activated more effectively on honeycomb films compared with on a flat film The cell response to honeycomb films (adhesion pattern and phosphorilation of FAK) was supposed to be originated from the regularly arraigned adsorption pattern of Fn determined by the pore structure of the film..
427. Masaru Tanaka, Masatsugu Shimomura, Biomedical application of patterned polymer films prepared by self-organization, J. Surf. Sci. Soc. Jap, 27, 170, 2006.
428. Yusuke Nishimori, Akira Mochizuki, Masaru Tanaka, Comparative study on blood compatibility of poly(MEA-HEMA) and poly(MEMA-HEMA), 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 2017, 2006, Blood compatibility of poly(MEA-co-HEMA) and poly(MEMA-co-HEMA) was investigated in terms of the composition of the copolymer and the difference of monomer species(MEA or MEMA). It was suggested that the contact phase in coagulation system had little effect on the activation of the system, and that there would be no difference among these copolymers in the activation of complement system via classical pathway induced by IgG complex..
429. Hiroshi Sunami, Emiko Ito, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cytoskeletone structure by using 3D microporus film, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 5422-5423, 2006, Micro fabrication of cell culture substrates is one of the most significant subjects in the field of biomaterial research. Recently we found that endothelial cells can proliferate rapidly on a micro 3D patterned film (honeycomb film). The cell shape and cytoskeleton structure on the honeycomb films were clearly different from those on a flat film. In order to elucidate the effect of honeycomb films as a 3D scaffold for cell culture, it is needed that the 3D observation of cell behaviors such as the morphological change, expression of cytoskeleton, expression of contact points on extracellular adhesion molecules, and migration on the honeycomb films during cell culture. In this research, effects of 3D honeycomb pattern on above cell behaviors were observed..
430. Hiroshi Sunami, Masaru Tanaka, Sadaaki Yamamoto, Emiko Ito, Masatsugu Shimomura, Control of the protein adsorption on honeycomb film by changing the pore size of honeycomb films, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1973, 2006, Micro fabrication of cell culture substrates is one of the most significant subjects in the field of biomaterial research. Recently we found that the proliferation of endothelial cells were influenced by the pore size of microporous polymer film (honeycomb film). It has been reported that adsorbed proteins on substrate play vital role in mediating cell proliferation. In order to elucidate the effect of the pore size of honeycomb films as a scaffold for cell culture, the observation of protein adsorption on honeycomb films during cell culture is needed. It was found the adsorbed protein structure on honeycomb films were greatly changed by changing pore size of honeycomb film. Further development of this approach should lead to surfaces which can control cell proliferation by changing the pore size of honeycomb films..
431. Keiko Yoshizawa, Masaru Tanaka, Akinori Tsuruma, Hiroshi Sunami, Sadaaki Yamamoto, Masatsugu Shimomura, Formation of hydroxyapatite on honeycomb films, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1929, 2006, We prepared biodegradable honeycomb films that covered with hydroxyapatite (HA) for bone tissue engineering scaffolds. The amount of HA was controlled by the time of the surface hydrolysis of the honeycomb films and the concentration of Simulated Body Fluid (SBF). The crystallization of HA was determined by X-ray diffraction. The roughness of the honeycomb surface before and after immersed in SBF was measured by AFM. The uniformity, the amount and the degree of crystallization of the HA precipitated on the honeycomb film depended on the time of hydrolysis of the films and the immersing time of the films in SBF..
432. Chiho Asahi, Masaru Tanaka, Jun Ichi Hamada, Yoshihide Toyokawa, Emiko Ito, Haruka Maeda, Sadaaki Yamamoto, Masatsugu Shimomura, Growth and motility of human cancer cells on honeycomb films, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 5491-5492, 2006, We examined the behavior of human cancer cells cultured on the honeycomb films prepared by the self-organization method. The growth of the cells on the honeycomb films was markedly reduced compared to that of the cells on the control flat films. The observation with a time-lapse video microscope revealed that the cells on the honeycomb films moved slower than those on the flat films. The cells attached to the honeycomb films were relatively resistant to detachment by trypsin-treatment compared to those attached to the flat films, suggesting stronger adhesiveness of the cells to honeycomb films than flat films. These suggest that the inhibitory effects on the growth and motility of the cells are in part due to their strong adhesiveness to honeycomb films..
433. Chiho Asahi, Masaru Tanaka, Jun Ichi Hamada, Yoshihide Toyokawa, Emiko Ito, Sadaaki Yamamoto, Masatsugu Shimomura, Growth inhibition of cancer cells on honeycomb films, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1918, 2006, We cultured cancer cells on honeycomb films prepared by the self-organization method and found that the growth of cancer cells on the films was inhibited. We observed that the cells had strongly adhered to honeycomb films and nuclear morphologies were unusual. We considered that the cell division on honeycomb film was inhibited. Honeycomb film could be used for new method of the cancer treatment and for the research of the cancer..
434. Akira Kishi, Masaru Tanaka, Akira Mochizuki, Measurement of ice crystal formation in biocompatible polymer by XRD-DSC, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 2139, 2006, Ice crystal formation behavior in biocompatible polymer was measured by simultaneous measuring instrument for XRD and DSC(XRD-DSC). Biocompatible polymer poly(2-methoxyethyl acrylate, PMEA) with saturated water showed exothermic DSC peak and hexagonal ice crystal XRD patterns at around -35°C. Whereas such behavior was not observed in not biocompatible polymer poly(2-hydroxyethyl methacrylate). Such weakly interacted water with polymer materials as observed in PMEA has important role in biocompatibility..
435. Takaharu Okajima, Masaru Tanaka, Shusaku Tsukiyama, Sadaaki Yamamoto, Masatsugu Shimomura, Hiroshi Tokumoto, Nano-dynamics of living cell surface by AFM, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 2109, 2006, Dynamics of living cell surface, hepatocyte was measured with an atomic force microscope (AFM). A thermal fluctuation spectroscopy, in which the thermal noise of cantilever is monitored to estimate the mechanical properties of sample surfaces, was for the first time applied to living cells. The power spectrum of cantilevers was analyzed using a harmonic oscillator with memory function of the friction coefficient. The results showed that the friction coefficient decreased with increasing the frequency in the range of 1-20 kHz, indicating the dispersion of the cell surface friction coefficient in the microsecond time domain..
436. Masatsugu Shimomura, Hiroshi Yabu, Masaru Tanaka, Novel nano- And micro- fabrication technique of polymer materials based on self-organization, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 100-102, 2006, We have utilized dynamic processes and dissipative structures emerged in the casting polymer solution for micro- and nano-patterning of polymer materials. We have found that the typical dissipative structures were formed in the casting process of polymer solutions on solid surfaces. Dynamic regular structures formed in casting polymer solutions are fixed as regular patterns, stripes, and lattices, etc., of polymer materials including nano-particles. We have also found that micro porous polymer films were prepared from water-immiscible solvent under humid casting condition. The patterned films can be applicable to optical and photonic devices as well as biomedical devices..
437. Akinori Tsuruma, Masaru Tanaka, Nobuyuki Fukushima, Sadaaki Yamamoto, Masatsugu Shimomura, Regulation of Neural stem cell differentiation, proliferation and forming of neural networks by changing pore size of self-organized honeycomb films, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 5393-5394, 2006, Neural stem cells (NSCs) have self-renewal potency and can differentiate into glial cells and neurons. It is important for neural tissue engineering to regulate differentiation and proliferation of NSCs. Recently, it has been reported that nano/micro patterned materials on substrates regulate cell morphologies, proliferation, differentiation and function. We have succeeded in preparing porous biodegradable polymer films with highly regular pores (honeycomb film) by a simple casting method. In this report, we cultured NSCs on honeycomb films (pore size, 3, 5, 8, and 10 μm) and investigated influences of the pore size on differentiation and proliferation of NSCs. On honeycomb films with pore size of 10 μm, NSCs differentiated into neurons. The neurons extended neurites along the honeycomb patterns. On the other hands, NSCs proliferated and formed spheroids on the honeycomb films with pore size of 3 μm. This study demonstrated for the first time that the proliferation and differentiation of NSCs are controlled by the structural patternens on substrates in minimum essential condition without using cytokines. The honeycomb films are potential scaffolds for neural tissue engineering..
438. Akinori Tsuruma, Masaru Tanaka, Nobuyuki Fukushima, Sadaaki Yamamoto, Masatsugu Shimomura, Regulation of neural stem cell differentiation and proliferation by self-organized honeycomb-patterned films, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1911, 2006, We have succeeded in preparing porous biodegradable polymer films with highly regular aligned pores in the shape of honeycomb (honeycomb film) by a simple casting method. In this report, we cultured NSCs on honeycomb films (pore size, 3, 5, 8, and 10 μm) and investigated influences of the pore size on differentiation and proliferation of NSCs. On honeycomb films with pore size of > 5 μm, NSCs differentiated into neurons. The neurons extended neurites along the honeycomb patterns, and neurite morphological changes depended on pore size of honeycomb films. On the other hands, NSCs proliferated and formed spheroids on the honeycomb films with pore size of 3 μm. This study shows that the honeycomb films are potential scaffolds for neural tissue engineering..
439. Masaru Tanaka, Relationship between adsorbed fibronectin and FAK activation on a honeycomb-patterned film, J. Surf. Sci. Soc. Jap, 27, 10, 2006.
440. Shoji Deguchi, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [16] protein adsorption onto different polymer films, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1940, 2006, Time-resolved IR spectra of protein adsorption process onto different polymer surface from buffer solution have been investigated by using an original in-situ attenuated total reflection infrared (ATR-IR) cell (Figure 1). Adsorbed protein is selectively observed, i.e. the signal from natural protein in solution is not detected by the method. Time-dependent spectral shape variation in the amide bands region (1700-1200cm-1) was observed (Figure 2). The spectral variation and the kinetics of adsorption will be discussed in detail..
441. Akiko Tanabe, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [23] multivariate analysis of time-resolved IR spectra upon water sorption into PMEA film, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4377-4378, 2006, Highly biocompatible polymer, poly(2-methoxy acrylate) (PMEA) has unique hydration structures. Confirmed by DSC, there exist three kinds of sorbed water: non-freezing, freezing bound and freezing water. From the difference IR spectra of the broad OH stretching band, each hydration band was reasonably separated but had significant noise. By using multivariate analysis method, these noisy bands were optimized to be smoother, and the coefficient for each band was determined and provided very meaningful quantitative information. Also, the plot of these coefficients against time, shown in Figure 3, indicates the water sorption kinetics concerning each component. This result verifies the band assignment and clarifies the water-polymer molecular interaction..
442. Shoji Deguchi, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [24] ATR-IR studied of protein adsorption onto biocompatible polymer, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4379-4380, 2006, Time-resolved IR spectra of protein adsorption process onto a polymer surface from buffer solution have been investigated by using an original in-situ attenuated total reflection infrared (ATR-IR) cell (Figure 1). The signal from adsorbed protein was selectively observed, i.e., that from natural protein in solution was not detected by the method. Figure 2 shows that the amide I bands (1700-1600cm-1) and the OD stretching band (2150-2200cm-1) regions of time-resolved spectra. Increase of amide I band and decrease of OD stretching band with time were observed (Figure 3). This result indicates that water molecules existing on the surface were desorbed by protein adsorption onto polymer surface. Protein adsorption from the aspect of water molecules will be discussed in detail..
443. Akiko Tanabe, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [17] sorption of small molecules, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1135, 2006, Sorption processes of small biomolecules into biocompatible polymers, poly(2-methoxy acrylate) (PMEA) and poly(2-hydroxyethyl methacrylate) (PHEMA), were investigated using time-resolved in-situ ATR-IR spectroscopy. Different hydration structures of PMEA were observed when small biomolecules were introduced as a form of buffer solutions into the polymer film. These solutions might influence the biocompatibility of PMEA since hydration structures of biocompatible polymers are important for their functions. The mechanism of sorption and dehydration processes of polymers will be discussed in detail using time-resolved IR spectra..
444. Shieeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [15] hydration structures of a PMEA film contacting with water, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1939, 2006, Hydration structures of a biocompatible polymer, poly(2-methoxyethyl acrylate) (PMEA), were investigated by in-situ ATR-IR spectroscopy. Time-resolved in-situ ATR-IR spectra of water sorption process into a PMEA film from dried condition to saturated hydration were monitored. Difference spectra, i.e., subtraction spectra at each time step A(tn) - A(t n-1), revealed that the band around 3600 cm-1 assigned to non-freezing water initially arises, followed by that around 3400 cm -1 of freezing bound water, and finally the band around 3200 cm -1 corresponds to freezing water increases. Hydration structures of each water in PMEA will be discussed in detail..
445. Yong Mei Chen, Masaru Tanaka, Jian Ping Gong, Yasuda Kazunori, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Surface properties of endothelial cells cultured on hydrogels, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4860, 2006, Blood compatibility is a one of basic parameters for artifical materials used in tissue engineering. It is well known that endothelial cells (ECs) have blood compatibility. Therefore, ECs are cultured on the surface of artificial materials for enhancing blood compatibility. Frictional stress and platelet adhesion on the surface of ECs cultured on various kinds of hydrogels were evaluated. It was found that the surface properties of ECs related on chemical structure and cross-linking concentration of the hydrogels, as well as the amount of glycocalyx on the EC surface..
446. Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Time-resolved IR observations of molecular sorption to a polymer film from a solution, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4278-4279, 2006, Time-resolved in-situ ATR-IR spectra of water sorption process into a biocompatible polymer, poly(2-methoxyethyl acrylate) (PMEA), were observed. Hydration structures of three different types of sorbed water in PMEA, i.e., non-freezing water, freezing bound water and freezing water, were discussed from the time-resolved IR spectra. ATR-IR spectra of water dissolved in a model monomer of 2-methoxyetyl acetate (MEAc) were also observed. ATR-IR spectrum of water in MEAc at 35 wt% shows similar spectra with that in PMEA at 9 wt% of saturated concentration. However, the mixture of water and MEAc (35 wt%) never shows cold crystallization peak in a DSC curve, implying that polymeric structure in PMEA may play an important role for the biocompatibility..
447. Masaru Tanaka, Masatsugu Shimomura, Biomedical application of patterned polymer films prepared by self-organization, J. Surf. Sci. Soc. Jap, 27, 170, 2006.
448. Hiroshi Sunami, Emiko Ito, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of cytoskeletone structure by using 3D microporus film, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 5422-5423, 2006, Micro fabrication of cell culture substrates is one of the most significant subjects in the field of biomaterial research. Recently we found that endothelial cells can proliferate rapidly on a micro 3D patterned film (honeycomb film). The cell shape and cytoskeleton structure on the honeycomb films were clearly different from those on a flat film. In order to elucidate the effect of honeycomb films as a 3D scaffold for cell culture, it is needed that the 3D observation of cell behaviors such as the morphological change, expression of cytoskeleton, expression of contact points on extracellular adhesion molecules, and migration on the honeycomb films during cell culture. In this research, effects of 3D honeycomb pattern on above cell behaviors were observed..
449. Chiho Asahi, Masaru Tanaka, Jun Ichi Hamada, Yoshihide Toyokawa, Emiko Ito, Sadaaki Yamamoto, Masatsugu Shimomura, Growth inhibition of cancer cells on honeycomb films, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 1918, 2006, We cultured cancer cells on honeycomb films prepared by the self-organization method and found that the growth of cancer cells on the films was inhibited. We observed that the cells had strongly adhered to honeycomb films and nuclear morphologies were unusual. We considered that the cell division on honeycomb film was inhibited. Honeycomb film could be used for new method of the cancer treatment and for the research of the cancer..
450. Akira Kishi, Masaru Tanaka, Akira Mochizuki, Measurement of ice crystal formation in biocompatible polymer by XRD-DSC, 55th SPSJ Annual Meeting Polymer Preprints, Japan - 55th SPSJ Annual Meeting, 55, 2139, 2006, Ice crystal formation behavior in biocompatible polymer was measured by simultaneous measuring instrument for XRD and DSC(XRD-DSC). Biocompatible polymer poly(2-methoxyethyl acrylate, PMEA) with saturated water showed exothermic DSC peak and hexagonal ice crystal XRD patterns at around -35°C. Whereas such behavior was not observed in not biocompatible polymer poly(2-hydroxyethyl methacrylate). Such weakly interacted water with polymer materials as observed in PMEA has important role in biocompatibility..
451. Masaru Tanaka, Relationship between adsorbed fibronectin and FAK activation on a honeycomb-patterned film, J. Surf. Sci. Soc. Jap, 27, 10, 2006.
452. Akiko Tanabe, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [23] multivariate analysis of time-resolved IR spectra upon water sorption into PMEA film, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4377-4378, 2006, Highly biocompatible polymer, poly(2-methoxy acrylate) (PMEA) has unique hydration structures. Confirmed by DSC, there exist three kinds of sorbed water: non-freezing, freezing bound and freezing water. From the difference IR spectra of the broad OH stretching band, each hydration band was reasonably separated but had significant noise. By using multivariate analysis method, these noisy bands were optimized to be smoother, and the coefficient for each band was determined and provided very meaningful quantitative information. Also, the plot of these coefficients against time, shown in Figure 3, indicates the water sorption kinetics concerning each component. This result verifies the band assignment and clarifies the water-polymer molecular interaction..
453. Shoji Deguchi, Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [24] ATR-IR studied of protein adsorption onto biocompatible polymer, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4379-4380, 2006, Time-resolved IR spectra of protein adsorption process onto a polymer surface from buffer solution have been investigated by using an original in-situ attenuated total reflection infrared (ATR-IR) cell (Figure 1). The signal from adsorbed protein was selectively observed, i.e., that from natural protein in solution was not detected by the method. Figure 2 shows that the amide I bands (1700-1600cm-1) and the OD stretching band (2150-2200cm-1) regions of time-resolved spectra. Increase of amide I band and decrease of OD stretching band with time were observed (Figure 3). This result indicates that water molecules existing on the surface were desorbed by protein adsorption onto polymer surface. Protein adsorption from the aspect of water molecules will be discussed in detail..
454. Yong Mei Chen, Masaru Tanaka, Jian Ping Gong, Yasuda Kazunori, Sadaaki Yamamoto, Masatsugu Shimomura, Yoshihito Osada, Surface properties of endothelial cells cultured on hydrogels, 55th Society of Polymer Science Japan Symposium on Macromolecules 55th SPSJ Symposium on Macromolecules, 55, 4860, 2006, Blood compatibility is a one of basic parameters for artifical materials used in tissue engineering. It is well known that endothelial cells (ECs) have blood compatibility. Therefore, ECs are cultured on the surface of artificial materials for enhancing blood compatibility. Frictional stress and platelet adhesion on the surface of ECs cultured on various kinds of hydrogels were evaluated. It was found that the surface properties of ECs related on chemical structure and cross-linking concentration of the hydrogels, as well as the amount of glycocalyx on the EC surface..
455. Hiromi Kitano, Susumu Tada, Takayuki Mori, Kohei Takaha, Makoto Gemmei-Ide, Masaru Tanaka, Mitsuhiro Fukuda, Yoshiyuki Yokoyama, Correlation between the structure of water in the vicinity of carboxybetaine polymers and their blood-compatibility, Langmuir, 10.1021/la0515571, 21, 25, 11932-11940, 2005.12, The structure and hydrogen bonding of water in the vicinity of carboxybetaine homopolymer (poly[1-carboxy-N,N-dimethyl-N-(2'- methacryloyloxyethyl)methanaminium inner salt] (PolyCMB), and a random copolymer of CMB and rc-butyl methacrylate, Poly(CMB-r-BMA), with various molecular weights were analyzed in their aqueous solutions and thin film with contours of O-H stretching of Raman and attenuated total reflection infrared (ATR-IR) spectra, respectively. The relative intensity of the collective band (C value) corresponding to a long-range coupling of O-H stretchings of the Raman spectra for aqueous solution of Poly(CMB-r-BMA) was very close to that for pure water, which is in contrast with the smaller C value in aqueous solution of ordinary poly electrolytes. The number of hydrogen bonds collapsed by the presence of one monomer residue (Ncorr value) of PolyCMB and Poly(CMB-r-BMA) (CMB, 45 mol %) (Mw, 1.14 × 104 and 1.78 × 10 4, respectively) could be calculated from the C value. The N corr values were much smaller than those for ordinary polyelectrolytes and close to those for nonionic water-soluble polymers such as poly(ethylene glycol) and poly(N-vinylpyrrolidone). Furthermore, a water-insoluble Poly(CMB-r-BMA) with a large BMA content (Mw = 347 kD, CMB 27 mol %) could be cast as a thin film (thickness, ca. 10 μm) on a ZnSe crystal for the ATR-IR analyses. At an early stage of sorption of water into the Poly(CMB-r-BMA) film, the O-H stretching band of IR spectra for the water incorporated in the film was similar to that for free water, which is in contrast with the drastic change in the O-H stretching band of water incorporated in polymer films such as poly(methyl methacrylate) (PMMA) and poly(n-butyl methacrylate) (PBMA). The theoretical vibrational frequency for water molecules hydrating a betaine molecule calculated by using a density functional method supported the experimental results. The adhesion of human platelets to Poly(CMB-r-BMA) films was much less than that to PMMA and PBMA. With an increase in the content of CMB residue, the number of platelets adhered to the Poly(CMB-r-BMA) film drastically decreased and then gradually increased, probably due to the increase in the roughness of the film surface. These results suggest that the carboxybetaine monomer residues with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules in both aqueous solution and thin film systems, resulting in the excellent blood-compatibility of the carboxybetaine polymers..
456. Hiromi Kitano, Susumu Tada, Takayuki Mori, Kohei Takaha, Makoto Gemmei-Ide, Masaru Tanaka, Mitsuhiro Fukuda, Yoshiyuki Yokoyama, Correlation between the structure of water in the vicinity of carboxybetaine polymers and their blood-compatibility, Langmuir, 10.1021/la0515571, 21, 25, 11932-11940, 2005.12, The structure and hydrogen bonding of water in the vicinity of carboxybetaine homopolymer (poly[1-carboxy-N,N-dimethyl-N-(2'- methacryloyloxyethyl)methanaminium inner salt] (PolyCMB), and a random copolymer of CMB and rc-butyl methacrylate, Poly(CMB-r-BMA), with various molecular weights were analyzed in their aqueous solutions and thin film with contours of O-H stretching of Raman and attenuated total reflection infrared (ATR-IR) spectra, respectively. The relative intensity of the collective band (C value) corresponding to a long-range coupling of O-H stretchings of the Raman spectra for aqueous solution of Poly(CMB-r-BMA) was very close to that for pure water, which is in contrast with the smaller C value in aqueous solution of ordinary poly electrolytes. The number of hydrogen bonds collapsed by the presence of one monomer residue (Ncorr value) of PolyCMB and Poly(CMB-r-BMA) (CMB, 45 mol %) (Mw, 1.14 × 104 and 1.78 × 10 4, respectively) could be calculated from the C value. The N corr values were much smaller than those for ordinary polyelectrolytes and close to those for nonionic water-soluble polymers such as poly(ethylene glycol) and poly(N-vinylpyrrolidone). Furthermore, a water-insoluble Poly(CMB-r-BMA) with a large BMA content (Mw = 347 kD, CMB 27 mol %) could be cast as a thin film (thickness, ca. 10 μm) on a ZnSe crystal for the ATR-IR analyses. At an early stage of sorption of water into the Poly(CMB-r-BMA) film, the O-H stretching band of IR spectra for the water incorporated in the film was similar to that for free water, which is in contrast with the drastic change in the O-H stretching band of water incorporated in polymer films such as poly(methyl methacrylate) (PMMA) and poly(n-butyl methacrylate) (PBMA). The theoretical vibrational frequency for water molecules hydrating a betaine molecule calculated by using a density functional method supported the experimental results. The adhesion of human platelets to Poly(CMB-r-BMA) films was much less than that to PMMA and PBMA. With an increase in the content of CMB residue, the number of platelets adhered to the Poly(CMB-r-BMA) film drastically decreased and then gradually increased, probably due to the increase in the roughness of the film surface. These results suggest that the carboxybetaine monomer residues with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules in both aqueous solution and thin film systems, resulting in the excellent blood-compatibility of the carboxybetaine polymers..
457. H Kitano, S Tada, T Mori, K Takaha, M Gemmei-Ide, M Tanaka, M Fukuda, Y Yokoyama, Correlation between the structure of water in the vicinity of carboxybetaine polymers and their blood-compatibility, LANGMUIR, 10.1021/la0515571, 21, 25, 11932-11940, 2005.12, The structure and hydrogen bonding of water in the vicinity of carboxybetaine homopolymer (poly[1-carboxy-N,N-dimethyl-N-(2'-methacryloyloxyethyl)methanaminium inner salt] (PolyCMB), and a random copolymer of CMB and n-butyl methacrylate, Poly(CMB-r-BMA), with various molecular weights were analyzed in their aqueous solutions and thin film with contours of O-H stretching of Raman and attenuated total reflection infrared (ATR-IR) spectra, respectively. The relative intensity of the collective band (C value) corresponding to a long-range coupling of O-H stretchings of the Raman spectra for aqueous solution of Poly(CMB-r-BMA) was very close to that for pure water, which is in contrast with the smaller C value in aqueous solution of ordinary polyelectrolytes. The number of hydrogen bonds collapsed by the presence of one monomer residue (N-corr value) of PolyCMB and Poly(CMB-r-BMA) (CMB, 45 mol %) (M-w 1.14 x 10(4) and 1.78 x 10(4), respectively) could be calculated from the C value. The N-corr values were much smaller than those for ordinary polyelectrolytes and close to those for nonionic water-soluble polymers such as poly(ethylene glycol) and poly(N-vinylpyrrolidone). Furthermore, a water-insoluble Poly(CMB-r-BMA) with a large BMA content (M-w = 347 kD, CMB 27 mol %) could be cast as a thin film (thickness, ca 10 mu m) on a ZnSe crystal for the ATR-IR analyses. At an early stage of sorption of water into the Poly(CMB-r-BMA) film, the O-H stretching band of IR spectra for the water incorporated in the film was similar to that for free water, which is in contrast with the drastic change in the O-H stretching band of water incorporated in polymer films such as poly(methyl methacrylate) (PMMA) and poly(n-butyl methacrylate) (PBMA). The theoretical vibrational frequency for water molecules hydrating a betaine molecule calculated by using a density functional method supported the experimental results, The adhesion of human platelets to Poly(CMB-r-BUA) films was much less than that to PMMA and PBMA. With an increase in the content of CMB residue, the number of platelets adhered to the Poly(CMB-r-BMA film drastically decreased and then gradually increased, probably due to the increase in the roughness of the film surface. These results suggest that the carboxybetaine monomer residues with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules in both aqueous solution and thin film systems, resulting in the excellent blood-compatibility of the carboxybetaine polymers..
458. Junji Nemoto, Yasumitsu Uraki, Takao Kishimoto, Yuzo Sano, Ryo Funada, Noriaki Obata, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Production of mesoscopically patterned cellulose film, Bioresource Technology, 10.1016/j.biortech.2005.01.034, 96, 17, 1955-1958, 2005.11, Honeycomb and stripe patterned films were prepared from cellulose triacetate (CTA)/chloroform solution, as a result of the self-organization of the polymer during evaporation of the solvent. The honeycomb patterned CTA films were prepared by two methods, a direct pattern formation method and a transcription method. The latter method gave a well-organized microporous honeycomb pattern. Both types of patterned CTA films were saponified to yield the corresponding patterned cellulose films..
459. Junji Nemoto, Yasumitsu Uraki, Takao Kishimoto, Yuzo Sano, Ryo Funada, Noriaki Obata, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Production of mesoscopically patterned cellulose film, Bioresource Technology, 10.1016/j.biortech.2005.01.034, 96, 17, 1955-1958, 2005.11, Honeycomb and stripe patterned films were prepared from cellulose triacetate (CTA)/chloroform solution, as a result of the self-organization of the polymer during evaporation of the solvent. The honeycomb patterned CTA films were prepared by two methods, a direct pattern formation method and a transcription method. The latter method gave a well-organized microporous honeycomb pattern. Both types of patterned CTA films were saponified to yield the corresponding patterned cellulose films..
460. Akinori Tsuruma, Masaru Tanaka, Nobuyuki Fukushima, Masatsugu Shimomura, Morphological changes in neurons by self-organized patterned films, e-Journal of Surface Science and Nanotechnology, 10.1380/ejssnt.2005.159, 3, 2005.05, In tissue engineering, micro/nanofabrication is important to modify substrate surfaces for regulating the attachment and growth of cells. In neuroscience, it is significant for neural regeneration; this involves guiding and extending dendrites and axons by a cell culture scaffold which acts as an extra cellular matrix. In this study, we prepared highly regular porous honeycomb-patterned films by a simple casting technique and cultured neurons to investigate their morphologies on the patterned films. The morphologies of neurons were examined by a scanning electron microscope and a confocal laser scanning microscope. The neurons were round and the neurites extended randomly on the flat film. The patterns influenced the morphologies of neurons. The morphologies of neurons were changed by varying the pore size of the honeycomb- patterned films. The neurites spread along the rims of the honeycomb pattern. These results suggest that the self-organized honeycomb-patterned films are useful biomaterials for neural tissue engineering..
461. Akinori Tsuruma, Masaru Tanaka, Nobuyuki Fukushima, Masatsugu Shimomura, Morphological changes in neurons by self-organized patterned films, e-Journal of Surface Science and Nanotechnology, 10.1380/ejssnt.2005.159, 3, 2005.05, In tissue engineering, micro/nanofabrication is important to modify substrate surfaces for regulating the attachment and growth of cells. In neuroscience, it is significant for neural regeneration; this involves guiding and extending dendrites and axons by a cell culture scaffold which acts as an extra cellular matrix. In this study, we prepared highly regular porous honeycomb-patterned films by a simple casting technique and cultured neurons to investigate their morphologies on the patterned films. The morphologies of neurons were examined by a scanning electron microscope and a confocal laser scanning microscope. The neurons were round and the neurites extended randomly on the flat film. The patterns influenced the morphologies of neurons. The morphologies of neurons were changed by varying the pore size of the honeycomb- patterned films. The neurites spread along the rims of the honeycomb pattern. These results suggest that the self-organized honeycomb-patterned films are useful biomaterials for neural tissue engineering..
462. Hiromi Kitano, Takayuki Mori, Yuki Takeuchi, Susumu Tada, Makoto Gemmei-Ide, Yoshiyuki Yokoyama, Masaru Tanaka, Structure of water incorporated in sulfobetaine polymer films as studied by ATR-FTIR, Macromolecular Bioscience, 10.1002/mabi.200400212, 5, 4, 314-321, 2005.04, The structure and hydrogen bonding of water in the vicinity of a thin film of a sulfobetaine copolymer (poly[(N,N-dimethyl-N-(3-sulfopropyl)-3′- methacrylamido-propanaminium inner salt)-ran-(butyl methacrylate)], poly(SPB-r-BMA)), were analyzed with band shapes of O-H stretching of attenuated total reflection infrared (ATR-IR) spectra. The copolymer could be cast as a thin film, of approximate thickness 10 μm, on a ZnSe crystal for the ATR-IR spectroscopy. At an early stage of sorption of water into the polymer film, the O-H stretching band of the IR spectra for the water incorporated in the film was similar to that for free water. This is consistent with the tendency for another zwitterionic polymeric material, poly[(2- methacryloyloxyethylphosphorylcholine)-ran-(butyl methacrylate)] (poly-(MPC-r-BMA). It is, however, contradictory to the drastic change in the O-H stretching band for water incorporated into films of polymers such as poly(2-hydroxyethyl methacrylate), poly(methyl methacrylate) and poly (butyl methacrylate). These results suggest that polymers with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules incorporated in the thin films. The investigation into the blood-compatibility of both the poly(SPB-r-BMA) and the poly (MPC-r-BMA) films indicate a definite correlation between the blood-compatibility of the polymers and the lack of effect of the polymeric materials on the structure of the incorporated water..
463. Hiroshi Yabu, Masafumi Takebayashi, Masaru Tanaka, Masatsugu Shimomura, Superhydrophobic and lipophobic properties of self-organized honeycomb and pincushion structures, Langmuir, 10.1021/la050013w, 21, 8, 3235-3237, 2005.04, This report describes the simple preparation of superhydrophobic and lipophobic surfaces by self-organization. Microporous polymer films of a fluorinated polymer with hexagonally arranged pores were prepared by casting from solution under humid conditions. Hexagonally packed water microdroplets were formed by evaporative cooling on the surface of the casting solution. After solvent evaporation, a honeycomb-patterned polymer film was formed with the water droplet array acting as a template; the water droplets themselves evaporated soon after the solvent. Two porous polymer layers were stacked vertically, separated by pillars at the hexagon vertexes. After peeling off the top layer using adhesive tape, a pincushion-like structure was obtained. Here, we show that superhydrophobic behavior was achieved, with the maximum contact angle, 170°, observed using these pincushion structures. Theoretical calculations fit the experimental results well. The lipophobic properties of the films are also discussed..
464. Hiromi Kitano, Takayuki Mori, Yuki Takeuchi, Susumu Tada, Makoto Gemmei-Ide, Yoshiyuki Yokoyama, Masaru Tanaka, Structure of water incorporated in sulfobetaine polymer films as studied by ATR-FTIR, Macromolecular Bioscience, 10.1002/mabi.200400212, 5, 4, 314-321, 2005.04, The structure and hydrogen bonding of water in the vicinity of a thin film of a sulfobetaine copolymer (poly[(N,N-dimethyl-N-(3-sulfopropyl)-3′- methacrylamido-propanaminium inner salt)-ran-(butyl methacrylate)], poly(SPB-r-BMA)), were analyzed with band shapes of O-H stretching of attenuated total reflection infrared (ATR-IR) spectra. The copolymer could be cast as a thin film, of approximate thickness 10 μm, on a ZnSe crystal for the ATR-IR spectroscopy. At an early stage of sorption of water into the polymer film, the O-H stretching band of the IR spectra for the water incorporated in the film was similar to that for free water. This is consistent with the tendency for another zwitterionic polymeric material, poly[(2- methacryloyloxyethylphosphorylcholine)-ran-(butyl methacrylate)] (poly-(MPC-r-BMA). It is, however, contradictory to the drastic change in the O-H stretching band for water incorporated into films of polymers such as poly(2-hydroxyethyl methacrylate), poly(methyl methacrylate) and poly (butyl methacrylate). These results suggest that polymers with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules incorporated in the thin films. The investigation into the blood-compatibility of both the poly(SPB-r-BMA) and the poly (MPC-r-BMA) films indicate a definite correlation between the blood-compatibility of the polymers and the lack of effect of the polymeric materials on the structure of the incorporated water..
465. Hiroshi Yabu, Masafumi Takebayashi, Masaru Tanaka, Masatsugu Shimomura, Superhydrophobic and lipophobic properties of self-organized honeycomb and pincushion structures, Langmuir, 10.1021/la050013w, 21, 8, 3235-3237, 2005.04, This report describes the simple preparation of superhydrophobic and lipophobic surfaces by self-organization. Microporous polymer films of a fluorinated polymer with hexagonally arranged pores were prepared by casting from solution under humid conditions. Hexagonally packed water microdroplets were formed by evaporative cooling on the surface of the casting solution. After solvent evaporation, a honeycomb-patterned polymer film was formed with the water droplet array acting as a template; the water droplets themselves evaporated soon after the solvent. Two porous polymer layers were stacked vertically, separated by pillars at the hexagon vertexes. After peeling off the top layer using adhesive tape, a pincushion-like structure was obtained. Here, we show that superhydrophobic behavior was achieved, with the maximum contact angle, 170°, observed using these pincushion structures. Theoretical calculations fit the experimental results well. The lipophobic properties of the films are also discussed..
466. Daisuke Ohsato, Takeshi Higuchi, Hiroshi Yabu, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Fabrication of novel biodegradable particles and application for DDS by self-organized precipitation method, 54th SPSJ Symposium on Macromolecules 54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan, 54, 4949-4950, 2005, Recently, we have reported the formation of nano-particles by mixing a poor solvent into a solution of polymer, and then evaporating a good solvent. In this report, nano-particles were prepared from various biodegradable polymers. Average size of the particles was measured by dynamic light scattering spectrophotometer. The particles were observed by Field-Emission Scanning Electron Microscopy. Uniform sized particles were formed. The particle size was controlled ranging from 100 nm to 1000 nm. In the case of Poly(ε- caprolactone)(PCL), the particle size became larger with increasing the concentration of solution, and increasing the volume ratio of a good solvent / a poor solvent. Fabrication of biodegradable particles containing a drug and the concentration of drug in the particles will be reported..
467. Masaru Tanaka, Fabrication of polymer based on self-organization and its application, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 61-63, 2005, We describe the fabrication and characterization of highly regular porous surfaces formed by a solution casting (bottom up) technique under humid air condition. Condensation of water from the air due to evaporation cooling was occurred when water-immissible solvent was used. Self-packed and mono-dispersed water droplets formed on the solution surface act as a temporary template of pores. Various experimental factors affecting the pore and pillar structures were studied. The porous surface shows a highly regular hexagonal arrangement of holes in a large area and can be easily peeled off from a substrate as a self-supported film. The pore size can be controlled in the range from 100 nm to 50 μm by changing the casting conditions. Unlike other templated or lithographic (top down) methods, advantage of this method is ease with which such patterned surfaces can be created using various materials. The 3-D patterned surfaces have a strong influence on the cell attachment and functions. The films with well-ordered nanostructure are applicable for biomedical-, photonic- and electronic materials..
468. Sadaaki Yamamoto, Hiroshi Sunami, Masaru Tanaka, Yasutaka Matsuo, Kuniharu Ijiro, Shigeko Yamashita, Yuka Morita, Masatsugu Shimomura, Influence of substratum surface morphologies on the structure of extracellular matrix on a honeycomb film, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 887, 2005, The substratum surface morphology plays vital roles in cellular behavior such as adhesion, spreading, migration, proliferation and differentiation We investigated here the structure of a cellular adhesive protein, fibronectin (Fn) adsorbed on both spin-coated films (flat film) and honeycomb pattern films made of poly-ε-caprolactone by using atomic force microscope and confocal laser scanning microscope in relation to the role of the substratum surface morphology in cellular behavior. Although the adsorption saturated at mono-layer adsorption level on both substrates, the structure was inhomogeneous and depend on the surface morphology of substrates: Fn formed fibril-like aggregates on the flat films. Contrary, they adsorbed around the pores on the honeycomb films..
469. Takaharu Okajima, Masaru Tanaka, Katsuhiro Ishii, Hiroshi Tokumoto, Nano-measuring living cell surface by AFM, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2376, 2005, An atomic force microscope (AFM) is a powerful tool for investigating soft materials in liquid environments. We developed a newly designed AFM, which employs a fiber-optic interferometer and a low coherence laser such as a super-luminescence diode. The advantage of this AFM is that this AFM is set up on a conventional optical microscope without blocking a light path for obtaining optical images and that the AFM does not suffer from a stray light of the fiber-optics, which is usually inevitable. It was demonstrated that the AFM could measure the small deflection of the AFM cantilever. Moreover, we developed a technique that precisely measures the contact point between the soft cell surfaces and an AFM tip. The result was that the spectrum of the thermally vibrated cantilever was drastically decreased when the tip contacted the surface, indicating that the method is useful for determining the contact of the tip-soft materials such as living cells in liquids..
470. Susumu Tada, Kazuya Mizukami, Makoto Gemmei-Ide, Hiromi Kitano, Masaru Tanaka, Relationship between the water structure in the vicinity of carboxybetaine polymers and their biocompatibility, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 1132, 2005, Structure of water in the vicinity of carboxybetaine(CMB), n-buthyl methacrylate(BMA) polymers and their copolymers with various compositions was investigated by using vibrational spectroscopies. Raman spectroscopy has revealed that, in contrast with ordinary polyelectrolytes, the zwitterionic polymers, PCMB and water-soluble P(BMA/CMB), did not affect the hydrogen-bonded network structure of water in their aqueous solutions. ATR-IR spectra of water sorbed into the P(BMA/CMB) films was similar to that of free water, but that in PBMA film was not. On the other hand, number of platelets adhered to the P(BMA/CMB) films was much smaller than that of PBMA film. These results suggest that the water structure is very important factor to generate biocompatibility of polymers..
471. Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [12] IR analysis of sorbed water into PMEA film, 54th SPSJ Symposium on Macromolecules 54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan, 54, 3858-3859, 2005, Time-resolved (TR) attenuated total reflection infrared (ATR-IR) spectra of sorbed water into biocompatible polymer, poly(2-methoxyethyl acrylate) (PMEA), have been investigated (Figure 1). Three broad and overlapped bands around 3600, 3400 and 3200 cm-1 are observed in the O-H stretching region of water due to H-bonds (Figure 2). Time-dependent spectral variation implies H-bonds structure changes between PMEA and water. Obtained spectral set was analyzed by perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy. A phase angle description spectrum of PCMW2D correlation demonstrates spectral variation order of the O-H stretching bands, i.e., higher wavenumber band around 3600 cm-1 is predominantly before changing, then 3400 cm-1, and then 3200 cm-1..
472. Etsuko Hirota, Masaru Tanaka, Akira Mochizuki, Study on surface structure, water structure, and blood compatibility of copolymers based on 2-methoxyethylacrylate or 2-methoxyethylmethacrylate, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2263, 2005, Two types of random copolymers (poly(MEA-co-HEMA) and poly(MEMA-co-HEMA) ware prepared, where MEMA and HEMA stand for 2-methoxyethylmethacrylate and 2-hydroxyethylmethacrylate, respectively. These copolymers were characterized from the view point of ESCA, contact angle, DSC, and platelet adhesion. The surface compositions of copolymers agreed with their bulk commotions in dry state, and contact angle results suggested no segregation. DSC analysis showed that MEMA based copolymer had no freezing bound water in the composition range from 100 to 60 mol% while MEMA based copolymer had it. Evaluations of blood compatibility for these polymers were carried out..
473. Etsuko Hirota, Koiohi Ute, Mitsunari Uehara, Tatsuki Kitayama, Masaru Tanaka, Akira Mochizuki, Surface analysis and evaluation of blood compatibility of MEA-HEMA block copolymer, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2005, Diblock copolymers composed of 2-methoxyethylacrylate (MEA) and 2-hydroxyethylmethacrylate were newly prepared by anion living polymerization. ESCA analysis showed the segregation of PMEA segment to the top surfaces of the copolymers, whereas contact angle results suggested that in wet state the surfaces were covered with PHEMA segment. Platelet adhesion test showed that these polymers had excellent blood compatibility..
474. Hiroshi Sunami, Naoko Ido, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, AFM observation of extracellular matrix adsorbed on thermosensitive polymer-films in water, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 914, 2005, Poly[2-(2-methoxyethoxy)ethyl methacrylate](PMEMA) with lower critical solution temperatures (LCST) of 22°C was prepared by free-radical polymerization of 2-(2-ethoxyethoxy)ethyl acrylate. The protein adsorption behavior was discussed by taking into account the changes in the surface properties of the polymer-films. There were much FBS proteins attached on the PMEMA films above the LCST compared to assays at lower temperature. Adsorption amounts of the proteins on the PMEMA films increased with increasing the temperature. These results showed that FBS protein adsorptions changed in surface properties governed by polymer transitions from hydrophilic to hydrophobic states..
475. Chiho Asahi, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Application of honeycomb film to medical devices, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2264, 2005, In this study, we prepared honeycomb films of the elastic polymers using the self-organization method in order to apply to the medical devices. We could control the pore shape of honeycomb films that have high elasticity and mechanical stability..
476. Hiroshi Sunami, Emiko Ito, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Control of the cell proliferation by using ECM adsorbed honeycomb films, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2232, 2005, Micro fabrication of cell culture substrates is one of the most significant subjects in the field of biomaterial research. Recently we found that endothelial cells can grow rapidly on a microporous polymer film (honeycomb film). In order to elucidate the effect of honeycomb films as a scaffold for cell culture, the observation of the honeycomb films during cell culture is needed. It was found that the topological and adsorbed protein structure on honeycomb films were greatly changed by conditioning. Further development of this approach should lead to surfaces which can be controlled cell proliferation by conditioning of surface structure on honeycomb films..
477. Emiko Itoh, Aiko Takayama, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Simomura, Control of vascular endothelial cell function by changing the pore size of self-organized porous films, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2234, 2005, Self-organized porous films (honeycomb films) with different pore size were prepared in order to investigate the influence of pore size on porcine arterial endothelial cells (PAECs) behavior. These films were fabricated by applying a moist air to a spread polymer solution containing biodegradable polymers (poly (ε-caprolactone)(PCL)) and an amphiphilic polymer. Four different pore sizes (5,10,12,16 μm) were prepared. Changes in cell morphology, proliferation, cytoskeleton and extra cellular matrix (ECM) (fibronectin, laminin, type IV collagen, elastin) production profiles were observed by optical, fluorescence, and scanning electron microscopy. The degree of spreading of PAECs was enhanced with increase of the pore size. PAECs proliferated on the honeycomb films. Almost the same ECM production profiles were obtained on the honeycomb films. These suggest that the honeycomb film is suitable as a material of a new vascular device..
478. Susumu Tada, Takayuki Mori, Makoto Gemmei-Ide, Hiromi Kitano, Mitsuhiro Fukuda, Masaru Tanaka, Correlation between the structure of water in the vicinity of carboxybetaine polymers and their biocompatibility, 54th SPSJ Symposium on Macromolecules 54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan, 54, 3826-3827, 2005, Structure of water in the vicinity of carboxybetaine (CMB), n-buthyl methacrylate (BMA) polymers and their copolymers with various compositions was investigated by using vibrational spectroscopies. Raman spectroscopy has revealed that, in contrast with ordinary polyelectrolytes, the zwitterionic polymers, PCMB and water-soluble P(BMA/CMB), did not affect the hydrogen-bonded network structure of water in their aqueous solutions. ATR-IR spectra of water sorbed into the P(BMA/CMB) films was similar to that of free water, but that in PBMA film was not. The number of platelets adhered to the P(BMA/CMB) films was much smaller than that into PBMA film. These results suggest that the water structure is very important factor to generate biocompatibility of polymers..
479. Yasumitsu Uraki, Hiroyuki Otsuka, Makoto Ubukata, Hiroshi Yabu, Masaru Tanaka, Masatsugu Shimomura, Creation of honeycomb-patterened cellulose by using a microorganism as a micro-machine, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 1561, 2005, An aim of this study is to create patterned polymer matrix by regulation of microorganism motion on the patterned template. In this report, we attempted to fabricate honeycomb-patterned cellulose produced by Acetobactor xylinum on the agarose gel with honeycomb-pattern microgrooves. Under atmospheric conditions, the bacteria proliferated significantly together with a small cellulose production. In order to enhance cellulose production and depress bacterial proliferation, several incubation conditions were investigated. Cellulose production was improved under humid conditions (RH 95%), but the proliferation was still active. Remarkable cellulose production with growth supression was observed in incubation under the CO 2 atmosphere with high humidity, while no cellulose production and proliferation was observed in the O 2 atmosphere. The thickness of the resulting cellulose patterned-matrix was approximately 1.3 μm. We are now investigating on fabrication of larger patterned cellulose matrix..
480. Daisuke Ohsato, Takeshi Higuchi, Hiroshi Yabu, Masaru Tanaka, Sadaaki Yamamoto, Masatsugu Shimomura, Fabrication of biodegradable particles for DDS by self-organized precipitation method, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 954, 2005, Recently, we have reported the formation of nano-particles by mixing a poor solvent into a solution of polymer, and then evaporating a good solvent. In this report, nano-particles were prepared from various biodegradable polymers. Average size of the particles was measured by dynamic light scattering spectrophotometer. The particles were observed by Field-Emission Scanning Electron Microscopy. Uniform sized particles were formed. The particle size was controlled ranging from 100 nm to 1000 nm. In the case of Poly(ε- caprolactone)(PCL), the particle size became larger with increasing the concentration of solution, and increasing the volume ratio of a good solvent / a poor solvent. Fabrication of biodegradable particles containing a drug and their concentration of drug in the particles will be reported..
481. Masaru Tanaka, Fabrication of polymer based on self-organization and its application, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 61-63, 2005, We describe the fabrication and characterization of highly regular porous surfaces formed by a solution casting (bottom up) technique under humid air condition. Condensation of water from the air due to evaporation cooling was occurred when water-immissible solvent was used. Self-packed and mono-dispersed water droplets formed on the solution surface act as a temporary template of pores. Various experimental factors affecting the pore and pillar structures were studied. The porous surface shows a highly regular hexagonal arrangement of holes in a large area and can be easily peeled off from a substrate as a self-supported film. The pore size can be controlled in the range from 100 nm to 50 μm by changing the casting conditions. Unlike other templated or lithographic (top down) methods, advantage of this method is ease with which such patterned surfaces can be created using various materials. The 3-D patterned surfaces have a strong influence on the cell attachment and functions. The films with well-ordered nanostructure are applicable for biomedical-, photonic- and electronic materials..
482. Shigeaki Morita, Masaru Tanaka, Yukihiro Ozaki, Studies on molecular structure of biocompatible polymers by vibrational spectroscopy [12] IR analysis of sorbed water into PMEA film, 54th SPSJ Symposium on Macromolecules 54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan, 54, 3858-3859, 2005, Time-resolved (TR) attenuated total reflection infrared (ATR-IR) spectra of sorbed water into biocompatible polymer, poly(2-methoxyethyl acrylate) (PMEA), have been investigated (Figure 1). Three broad and overlapped bands around 3600, 3400 and 3200 cm-1 are observed in the O-H stretching region of water due to H-bonds (Figure 2). Time-dependent spectral variation implies H-bonds structure changes between PMEA and water. Obtained spectral set was analyzed by perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy. A phase angle description spectrum of PCMW2D correlation demonstrates spectral variation order of the O-H stretching bands, i.e., higher wavenumber band around 3600 cm-1 is predominantly before changing, then 3400 cm-1, and then 3200 cm-1..
483. Etsuko Hirota, Koiohi Ute, Mitsunari Uehara, Tatsuki Kitayama, Masaru Tanaka, Akira Mochizuki, Surface analysis and evaluation of blood compatibility of MEA-HEMA block copolymer, 54th SPSJ Annual Meeting 2005 54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan, 54, 2005, Diblock copolymers composed of 2-methoxyethylacrylate (MEA) and 2-hydroxyethylmethacrylate were newly prepared by anion living polymerization. ESCA analysis showed the segregation of PMEA segment to the top surfaces of the copolymers, whereas contact angle results suggested that in wet state the surfaces were covered with PHEMA segment. Platelet adhesion test showed that these polymers had excellent blood compatibility..
484. Masaru Tanaka, M. Takebayashi, K. Sato, M. Shimomura, Fabrication of self-organized porous films -Tissue engineering scaffolds and biomedical devices, Transactions - 7th World Biomaterials Congress Transactions - 7th World Biomaterials Congress, 2004.12, The fabrication and characterization of highly regular porous polymer films formed by simple casting technique and the scaffolds was investigated. The porous films showed a highly regular hexagonal arrangement of holes in a large area, which could be easily peeled off from a glass substrate as a self-supported porous films. Hexagonal arrays of polymer pillars were also fabricated and characterized. The pillared film with well-ordered structure could be applicable for biomedical-, photonic- and electronic materials..
485. Masaru Tanaka, Design of novel biointerfaces (I). Blood compatibility of poly(2-methoxyethyl acrylate), Bio-Medical Materials and Engineering, 14, 4, 427-438, 2004.12, We have reported that poly(2-methoxyethyl acrylate) (PMEA) shows excellent blood compatibility with respect to the coagulation, complement, leukocyte and platelet systems in vitro and ex vivo when compared with other polymer surfaces. In this study, to clarify the reasons for this good compatibility, the structure of water in the hydrated PMEA were investigated and compared to water structure of poly(2-hydroxyethyl methacrylate) (PHEMA) and polyacrylate analogs as references. The hydrated water in PMEA could be classified into three types; free water, freezing-bound water, and non-freezing water. Cold crystallization of water in the heating process was clearly observed at -42°C. This cold crystallization is interpreted as the phase transition from the amorphous ice to the crystal ice that belongs to the freezing-bound water in PMEA. On the other hand, the cold crystallization peak (freezing bound water; which prevents the biocomponents from contacting the polymer surface or non-freezing water on the polymer surface) was not observed for hydrated PHEMA and PMEA analogous polymers. We hypothesized that the freezing-bound water layer between free water and non-freezing water was an important factor for the excellent blood compatibility of PMEA..
486. Masaru Tanaka, Masafumi Takebayashi, Masashi Miyama, Jin Nishida, Masatsugu Shimomura, Design of novel biointerfaces (II). Fabrication of self-organized porous polymer film with highly uniform pores, Bio-Medical Materials and Engineering, 14, 4, 439-446, 2004.12, Application of porous polymer materials to novel bio-interfaces for tissue engineering scaffold and artificial organs including blood filters, dialyzer, and oxygenator membranes have been in progress. The present study describes the fabrication and characterization of self-organized highly regular porous polymer films with uniform pore sizes are prepared by simple casting technique. Various fabrication parameters affecting the pore size such as polymer concentration, boiling point of solvent, cast volume and substrate are studied. The pore size can be controlled in the range from 1 to 50 μm by changing the evaporation rate of the polymer solutions. The porous film with uniform pore size is used for tissue engineering scaffold and cell separation membrane. To simulate the leukocyte eliminating from human blood, the porous film was attached to a module. The films with 5-9 μm pores provided the complete selectivity of separation for the leukocyte from the whole blood. The leukocyte elimination ratio depends on pore structures (size and depth) as well as recovery of platelet and erythrocyte..
487. M. Tanaka, M. Takebayashi, K. Sato, M. Shimomura, Fabrication of self-organized porous films -Tissue engineering scaffolds and biomedical devices, Transactions - 7th World Biomaterials Congress Transactions - 7th World Biomaterials Congress, 2004.12, The fabrication and characterization of highly regular porous polymer films formed by simple casting technique and the scaffolds was investigated. The porous films showed a highly regular hexagonal arrangement of holes in a large area, which could be easily peeled off from a glass substrate as a self-supported porous films. Hexagonal arrays of polymer pillars were also fabricated and characterized. The pillared film with well-ordered structure could be applicable for biomedical-, photonic- and electronic materials..
488. A. Tsuruma, M. Tanaka, N. Fukushima, M. Shimomura, Reconstruction of neural network by self-organized polymer substrates, Transactions - 7th World Biomaterials Congress Transactions - 7th World Biomaterials Congress, 2004.12, Reconstruction of neural network using self-organized polymer substrates was analyzed. Poly( ε -caprolactone)(PCL) and amphipathic polymer were mixed together and dissolved in chloroform at weight ratio of 10 vs 1. Tissues were transferred to culture medium containing 55μM 2-mercaptoethanol and gently triturated with a fire polished pasteur pipette until tissues were mostly dissociated into sigle cells. The results show that self-organized patterned films could provide guidance of neurite extension and scaffold of neural tissue engineering..
489. Masaru Tanaka, Design of novel biointerfaces (I). Blood compatibility of poly(2-methoxyethyl acrylate), Bio-Medical Materials and Engineering, 14, 4, 427-438, 2004.06, We have reported that poly(2-methoxyethyl acrylate) (PMEA) shows excellent blood compatibility with respect to the coagulation, complement, leukocyte and platelet systems in vitro and ex vivo when compared with other polymer surfaces. In this study, to clarify the reasons for this good compatibility, the structure of water in the hydrated PMEA were investigated and compared to water structure of poly(2-hydroxyethyl methacrylate) (PHEMA) and polyacrylate analogs as references. The hydrated water in PMEA could be classified into three types; free water, freezing-bound water, and non-freezing water. Cold crystallization of water in the heating process was clearly observed at -42°C. This cold crystallization is interpreted as the phase transition from the amorphous ice to the crystal ice that belongs to the freezing-bound water in PMEA. On the other hand, the cold crystallization peak (freezing bound water; which prevents the biocomponents from contacting the polymer surface or non-freezing water on the polymer surface) was not observed for hydrated PHEMA and PMEA analogous polymers. We hypothesized that the freezing-bound water layer between free water and non-freezing water was an important factor for the excellent blood compatibility of PMEA..
490. Masaru Tanaka, Masafumi Takebayashi, Masashi Miyama, Jin Nishida, Masatsugu Shimomura, Design of novel biointerfaces (II). Fabrication of self-organized porous polymer film with highly uniform pores, Bio-Medical Materials and Engineering, 14, 4, 439-446, 2004.06, Application of porous polymer materials to novel bio-interfaces for tissue engineering scaffold and artificial organs including blood filters, dialyzer, and oxygenator membranes have been in progress. The present study describes the fabrication and characterization of self-organized highly regular porous polymer films with uniform pore sizes are prepared by simple casting technique. Various fabrication parameters affecting the pore size such as polymer concentration, boiling point of solvent, cast volume and substrate are studied. The pore size can be controlled in the range from 1 to 50 μm by changing the evaporation rate of the polymer solutions. The porous film with uniform pore size is used for tissue engineering scaffold and cell separation membrane. To simulate the leukocyte eliminating from human blood, the porous film was attached to a module. The films with 5-9 μm pores provided the complete selectivity of separation for the leukocyte from the whole blood. The leukocyte elimination ratio depends on pore structures (size and depth) as well as recovery of platelet and erythrocyte..
491. Masaru Tanaka, Akira Mochizuki, Effect of water structure on blood compatibility - Thermal analysis of water in poly(meth)acrylate, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.20088, 68, 4, 684-695, 2004.03, The purpose of this study is to clarify the main factor causing excellent blood compatibility of poly(2-methoxyethyl acrylate)(PMEA) by the comparison between PMEA and seven PMEA analogous polymers. The polymers have a typical functional group as ester side chains such as methoxyethyl, hydroxyethyl, phenoxyethyl, and alkyl groups. The properties of the polymers relating to water were investigated in terms of contact angle, equilibrium water content (EWC), and thermal analysis by differential scanning calorimetry. The water in PMEA could be classified into three types: nonfreezing water, freezing bound water, and free water while the water in the analogous polymers was classified into just two types: free and non-freezing waters, regardless of the chemical structure of the side chain. The surface property represented by the contact angle of water corresponded to the content of the bound water (nonfreezing water + freezing bound water). The platelet compatibility in vitro did not depend on the contents of these waters, or on the contact angle. On the basis of the results of this work and the previous work on the platelet compatibility of poly(MEA-co-HEMA) (Tanaka et al. Biomacromolecules 2002;3;36-41), the main factor causing the excellent compatibility of PMEA is discussed..
492. Masaru Tanaka, Akira Mochizuki, Effect of water structure on blood compatibility - Thermal analysis of water in poly(meth)acrylate, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.20088, 68, 4, 684-695, 2004.03, The purpose of this study is to clarify the main factor causing excellent blood compatibility of poly(2-methoxyethyl acrylate)(PMEA) by the comparison between PMEA and seven PMEA analogous polymers. The polymers have a typical functional group as ester side chains such as methoxyethyl, hydroxyethyl, phenoxyethyl, and alkyl groups. The properties of the polymers relating to water were investigated in terms of contact angle, equilibrium water content (EWC), and thermal analysis by differential scanning calorimetry. The water in PMEA could be classified into three types: nonfreezing water, freezing bound water, and free water while the water in the analogous polymers was classified into just two types: free and non-freezing waters, regardless of the chemical structure of the side chain. The surface property represented by the contact angle of water corresponded to the content of the bound water (nonfreezing water + freezing bound water). The platelet compatibility in vitro did not depend on the contents of these waters, or on the contact angle. On the basis of the results of this work and the previous work on the platelet compatibility of poly(MEA-co-HEMA) (Tanaka et al. Biomacromolecules 2002;3;36-41), the main factor causing the excellent compatibility of PMEA is discussed..
493. Guifeng Li, Shigeaki Morita, Shen Ye, Masaru Tanaka, Masatoshi Osawa, Quartz Crystal Microbalance and Infrared Reflection Absorption Spectroscopy Characterization of Bisphenol A Absorption in the Poly(acrylate) Thin Films, Analytical Chemistry, 10.1021/ac0348874, 76, 3, 788-795, 2004.02, The absorption process of bisphenol A (BPA) in a number of poly(acrylate) thin films, such as poly(2-methoxyethyl acrylate) (PMEA), poly(ethyl acrylate) (PEA), poly(n-butyl methacrylate) (PBMA), and poly(methyl methacrylate) (PMMA), has been investigated by quartz crystal microbalance (QCM) and infrared reflection absorption spectroscopy (IRRAS) measurements. Both QCM and IRRAS measurements show that the BPA molecules absorb in PMEA, PEA, and PBMA thin films but not in PMMA thin film. The differences in the BPA absorption behavior are mainly attributed to the difference in the glass transition temperature (Tg) between these polymers. This absorption behavior also depends on the BPA concentration and polymer film thickness. Furthermore, IRRAS characterization demonstrates that the hydrogen bonding is formed between the hydroxyl group in BPA and the carbonyl group in the poly(acrylate) thin films. BPA molecule absorbed in these polymer thin films can be removed by ethanol rinse treatment. By optimizing experimental conditions for the QCM electrode modified by PMEA thin film, detection limitation of ∼1 ppb for BPA can be realized by the in situ QCM measurement. This method is expected to be a sensitive in situ detection way for trace BPA in the environmental study..
494. Guifeng Li, Shigeaki Morita, Shen Ye, Masaru Tanaka, Masatoshi Osawa, Quartz Crystal Microbalance and Infrared Reflection Absorption Spectroscopy Characterization of Bisphenol A Absorption in the Poly(acrylate) Thin Films, Analytical chemistry, 10.1021/ac0348874, 76, 3, 788-795, 2004.02, The absorption process of bisphenol A (BPA) in a number of poly(acrylate) thin films, such as poly(2-methoxyethyl acrylate) (PMEA), poly(ethyl acrylate) (PEA), poly(n-butyl methacrylate) (PBMA), and poly(methyl methacrylate) (PMMA), has been investigated by quartz crystal microbalance (QCM) and infrared reflection absorption spectroscopy (IRRAS) measurements. Both QCM and IRRAS measurements show that the BPA molecules absorb in PMEA, PEA, and PBMA thin films but not in PMMA thin film. The differences in the BPA absorption behavior are mainly attributed to the difference in the glass transition temperature (Tg) between these polymers. This absorption behavior also depends on the BPA concentration and polymer film thickness. Furthermore, IRRAS characterization demonstrates that the hydrogen bonding is formed between the hydroxyl group in BPA and the carbonyl group in the poly(acrylate) thin films. BPA molecule absorbed in these polymer thin films can be removed by ethanol rinse treatment. By optimizing experimental conditions for the QCM electrode modified by PMEA thin film, detection limitation of ∼1 ppb for BPA can be realized by the in situ QCM measurement. This method is expected to be a sensitive in situ detection way for trace BPA in the environmental study..
495. GF Li, S Morita, S Ye, M Tanaka, M Osawa, Quartz crystal microbalance and infrared reflection absorption spectroscopy characterization of bisphenol A absorption in the poly(acrylate) thin films, ANALYTICAL CHEMISTRY, 10.1021/ac0348874, 76, 3, 788-795, 2004.02, The absorption process of bisphenol A (BPA) in a number of poly(acrylate) thin films, such as poly(2-methoxyethyl acrylate) (PMEA), poly(ethyl acrylate) (PEA), poly(n-butyl methacrylate) (PBMA), and poly(methyl methacrylate) (PMMA), has been investigated by quartz crystal microbalance (QCM) and infrared reflection absorption spectroscopy (IRRAS) measurements. Both QCM and IRRAS measurements show that the BPA molecules absorb in PMEA, PEA, and PBMA thin films but not in PMMA thin film. The differences in the BPA absorption behavior are mainly attributed to the difference in the glass transition temperature (T-g) between these polymers. Ibis absorption behavior also depends on the BPA concentration and polymer film thickness. Furthermore, IRRAS characterization demonstrates that the hydrogen bonding is formed between the hydroxyl group in BPA and the carbonyl group in the poly(acrylate) thin films. BPA molecule absorbed in these polymer thin films can be removed by ethanol rinse treatment. By optimizing experimental conditions for the QCM electrode modified by PMEA thin film, detection limitation of similar to1 ppb for BPA can be realized by the in situ QCM measurement. This method is expected to be a sensitive in situ detection way for trace BPA in the environmental study..
496. Akinori Tsuruma, Masaru Tanaka, Nobuyuki Fukushima, Masatsugu Shimomura, Morphological changes of neurons on self-organized honeycomb patterned films, Kobunshi Ronbunshu, 10.1295/koron.61.628, 61, 12, 628-633, 2004.01, Recently, micro-nano fabrication has become an important way to modify material's surfaces for reguration of adhesion and growth of cells in tissue engineering. In neuroscience, micro-patterns on culture substrates are critical for neurological implants and are also significant to investigate neuron-patterned surface interactions. In previous studies, the patterns have been fabricated by lithography and microcontact printing techniques. However, these techniques need high energy and many processes and restricted can only treat a list of materials for substrates. In this study, we prepared self-organized honeycomb-patterned films by a casting technique. We cultured neurons on the patterned films for neural tissue engineering and investigated the morphology of neural cell bodies and neural network by a confocal scanning microscope and a scanning electron microscope. We found that neurons formed neural network along the honeycomb patterns and that the morphologies of attached cells depended on pore size of the patterned films. These results suggest that honeycomb-patterned films provide guidance of neurite extension and influence the morphologies of neurons..
497. Akinori Tsuruma, Masaru Tanaka, Nobuyuki Fukushima, Masatsugu Shimomura, Morphological changes of neurons on self-organized honeycomb patterned films, KOBUNSHI RONBUNSHU, 10.1295/koron.61.628, 61, 12, 628-633, 2004.01, Recently, micro-nano fabrication has become an important way to modify material's surfaces for reguration of adhesion and growth of cells in tissue engineering. In neuroscience, micro-patterns on culture substrates are critical for neurological implants and are also significant to investigate neuron-patterned surface interactions. In previous studies, the patterns have been fabricated by lithography and microcontact printing techniques. However, these techniques need high energy and many processes and restricted can only treat a list of materials for substrates. In this study, we prepared self-organized honeycomb-patterned films by a casting technique. We cultured neurons on the patterned films for neural tissue engineering and investigated the morphology of neural cell bodies and neural network by a confocal scanning microscope and a scanning electron microscope. We found that neurons formed neural network along the honeycomb patterns and that the morphologies of attached cells depended on pore size of the patterned films. These results suggest that honeycomb-patterned films provide guidance of neurite extension and influence the morphologies of neurons..
498. A. Tsuruma, Masaru Tanaka, N. Fukushima, M. Shimomura, Reconstruction of neural network by self-organized polymer substrates, Transactions - 7th World Biomaterials Congress Transactions - 7th World Biomaterials Congress, 1561, 2004, Reconstruction of neural network using self-organized polymer substrates was analyzed. Poly( ε -caprolactone)(PCL) and amphipathic polymer were mixed together and dissolved in chloroform at weight ratio of 10 vs 1. Tissues were transferred to culture medium containing 55μM 2-mercaptoethanol and gently triturated with a fire polished pasteur pipette until tissues were mostly dissociated into sigle cells. The results show that self-organized patterned films could provide guidance of neurite extension and scaffold of neural tissue engineering..
499. Masaru Tanaka, Blood compatibility of poly(2-methoxyethyl acrylate) - Design novel biointerfaces, KOBUNSHI RONBUNSHU, 10.1295/koron.60.415, 60, 8, 415-427, 2003.08, The Poly(2-methoxyethyl acrylate) (PMEA) surface shows excellent blood compatibility with respect to the coagulation, complement, and platelet systems when compared with other polymer surfaces. To clarify the reasons for this good compatibility, kinetics of protein adsorption and desorption on PMEA surface, and the structure of water in the hydrated PMEA were investigated. Poly(2-hydroxyethyl methacrylate) (PHEMA) and polyacrylate analogs were used as references. The amount of protein adsorbed onto PMEA was very small, and close to that adsorbed onto PHEMA. PMEA showed the low denaturation and the high dissociation rate constant of the proteins adsorbed onto PMEA. The hydrated water in PMEA could be classified into three types; free water, freezing-bound water, and non-freezing water. Cold crystallization of water in the heating process was clearly observed at -42 °C. This cold crystallization is interpreted as the phase transition from the amorphous ice to the crystal ice that belongs to the freezing-bound water in PMEA. We hypothesized that the freezing-bound water layer between free water and non-freezing water was an important factor for the excellent blood compatibility of PMEA. The present study also describes the fabrication and characterization of highly regular porous polymer films formed by a simple casting technique. The porous film with controlled pore size from 0.2 to 100 μm is used for tissue engineering scaffolds and biomedical devices..
500. Hiroshi Yabu, Masaru Tanaka, Kuniharu Ijiro, Masatsugu Shimomura, Preparation of honeycomb-patterned polyimide films by self-organization, Langmuir, 10.1021/la034454w, 19, 15, 6297-6300, 2003.07, Microporous polymer films are attractive materials with potential application in the fields of electronics, photonics, and biotechnology. Chemical and thermal stabilities of the microporous polymer films are required for their materials application. Besides preparation by conventional photolithography, we have reported that honeycomb-patterned porous polymer films are prepared by a method utilizing the condensation of small water droplets on solutions of amphiphilic copolymers. Here, we show preparation of honeycomb-patterned microporous films of a thermally and chemically stable material, polyimide. A water-template-assisted honeycomb structure was formed from a polyion complex of polyamic acids and dialkylammonium salt. The pore size of films was controlled by the casting volume of polymer solution. The patterned polyion complex film converted into polyimide by simple chemical treatment, keeping the porous structure. Self-supporting microporous polyimide films are fabricated. The honeycomb-structured film has high thermal and chemical stability like that of conventional cast films of polyimides..
501. Shen Ye, Shigeaki Morita, Guifeng Li, Hiroyuki Noda, Masaru Tanaka, Kohei Uosaki, Masatoshi Osawa, Structural changes in poly(2-methoxyethyl acrylate) thin films induced by absorption of bisphenol A. An infrared and sum frequency generation (SFG) study, Macromolecules, 10.1021/ma026007d, 36, 15, 5694-5703, 2003.07, The structural changes in poly(2-methoxyethyl acrylate) (PMEA) thin films induced by the absorption of bisphenol A (BPA), which is suspected to be an endocrine disrupter disturbing the hormone balance in a living body, have been investigated by infrared reflection absorption spectroscopy (IRRAS) and sum frequency generation (SFG) measurements. BPA molecules are absorbed in PMEA thin film. By controlling the thickness of the intermediate polystyrene (PS) film between the PMEA and Au substrate, we are able to probe the molecular structure at the different PMEA interfaces of air/PMEA (free) and PMEA/PS (buried) by the SFG measurements. The ether methyl (OCH3) group in the side chain of PMEA at both interfaces has the same vector orientation with respect to Au, i.e., pointing into air at the free interface and pointing into PMEA at the PMEA/PS buried interface. The OCH3 groups at the PMEA interfaces are likely to stand up and that the interfacial ordering on the PMEA is increased by the BPA absorption. The structural changes in the PMEA bulk and its interface induced by BPA absorption and desorption are reversible..
502. Hiroshi Yabu, Masaru Tanaka, Kuniharu Ijiro, Masatsugu Shimomura, Preparation of honeycomb-patterned polyimide films by self-organization, Langmuir, 10.1021/la034454w, 19, 15, 6297-6300, 2003.07, Microporous polymer films are attractive materials with potential application in the fields of electronics, photonics, and biotechnology. Chemical and thermal stabilities of the microporous polymer films are required for their materials application. Besides preparation by conventional photolithography, we have reported that honeycomb-patterned porous polymer films are prepared by a method utilizing the condensation of small water droplets on solutions of amphiphilic copolymers. Here, we show preparation of honeycomb-patterned microporous films of a thermally and chemically stable material, polyimide. A water-template-assisted honeycomb structure was formed from a polyion complex of polyamic acids and dialkylammonium salt. The pore size of films was controlled by the casting volume of polymer solution. The patterned polyion complex film converted into polyimide by simple chemical treatment, keeping the porous structure. Self-supporting microporous polyimide films are fabricated. The honeycomb-structured film has high thermal and chemical stability like that of conventional cast films of polyimides..
503. Shen Ye, Shigeaki Morita, Guifeng Li, Hiroyuki Noda, Masaru Tanaka, Kohei Uosaki, Masatoshi Osawa, Structural changes in poly(2-methoxyethyl acrylate) thin films induced by absorption of bisphenol A. An infrared and sum frequency generation (SFG) study, Macromolecules, 10.1021/ma026007d, 36, 15, 5694-5703, 2003.07, The structural changes in poly(2-methoxyethyl acrylate) (PMEA) thin films induced by the absorption of bisphenol A (BPA), which is suspected to be an endocrine disrupter disturbing the hormone balance in a living body, have been investigated by infrared reflection absorption spectroscopy (IRRAS) and sum frequency generation (SFG) measurements. BPA molecules are absorbed in PMEA thin film. By controlling the thickness of the intermediate polystyrene (PS) film between the PMEA and Au substrate, we are able to probe the molecular structure at the different PMEA interfaces of air/PMEA (free) and PMEA/PS (buried) by the SFG measurements. The ether methyl (OCH3) group in the side chain of PMEA at both interfaces has the same vector orientation with respect to Au, i.e., pointing into air at the free interface and pointing into PMEA at the PMEA/PS buried interface. The OCH3 groups at the PMEA interfaces are likely to stand up and that the interfacial ordering on the PMEA is increased by the BPA absorption. The structural changes in the PMEA bulk and its interface induced by BPA absorption and desorption are reversible..
504. K Tanaka, M Tanaka, Simulations of nanometric optical circuits: Open-type surface plasmon polariton gap waveguide, JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, 10.1143/JJAP.42.L585, 42, 6A, L585-L588, 2003.06, Three-dimensional numerical simulations of open-type surface plasmon polariton gap waveguide (o-SPGW) circuits are performed. The construction of open-type E-plane SPGW circuits is much easier than that of the closed-type SPGW circuits proposed previously. E-plane nanometric optical circuits consisting of straight, branched and bent o-SPGWs are studied in this work, and simulation results demonstrate that optical circuits using o-SPGWs provide effective guiding, branching and bending functions in nanometric devices..
505. Masaru Tanaka, Blood compatibility of poly(2-methoxyethyl acrylate) - Design novel biointerfaces, Kobunshi Ronbunshu, 10.1295/koron.60.415, 60, 8, 415-427, 2003.01, The Poly(2-methoxyethyl acrylate) (PMEA) surface shows excellent blood compatibility with respect to the coagulation, complement, and platelet systems when compared with other polymer surfaces. To clarify the reasons for this good compatibility, kinetics of protein adsorption and desorption on PMEA surface, and the structure of water in the hydrated PMEA were investigated. Poly(2-hydroxyethyl methacrylate) (PHEMA) and polyacrylate analogs were used as references. The amount of protein adsorbed onto PMEA was very small, and close to that adsorbed onto PHEMA. PMEA showed the low denaturation and the high dissociation rate constant of the proteins adsorbed onto PMEA. The hydrated water in PMEA could be classified into three types; free water, freezing-bound water, and non-freezing water. Cold crystallization of water in the heating process was clearly observed at -42 °C. This cold crystallization is interpreted as the phase transition from the amorphous ice to the crystal ice that belongs to the freezing-bound water in PMEA. We hypothesized that the freezing-bound water layer between free water and non-freezing water was an important factor for the excellent blood compatibility of PMEA. The present study also describes the fabrication and characterization of highly regular porous polymer films formed by a simple casting technique. The porous film with controlled pore size from 0.2 to 100 μm is used for tissue engineering scaffolds and biomedical devices..
506. Makoto Ide, Takayuki Mori, Ken Ichikawa, Hiromi Kitano, Masaru Tanaka, Akira Mochizuki, Hiroaki Oshiyama, Wataru Mizuno, Structure of water sorbed into poly(MEA-co-HEMA) films as examined by ATR-IR spectroscopy, Langmuir, 10.1021/la020617p, 19, 2, 429-435, 2003.01, The structure of water sorbed into poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and their copolymers (p(MEA/HEMA)) was investigated by attenuated total reflection infrared (ATR-IR) spectroscopy. The extinction coefficient of the OH stretching band of sorbed water (εOH) was calculated from the band area obtained by IR measurement and the amount of sorbed water obtained by thermogravimetric analysis. When the polymers contacted with water vapor (relative humidity = ∼55%), the eon values were quite similar in all polymers. On the other hand, when the polymers contacted with liquid water, the εOH values were drastically changed by the content of 2-methoxyethyl acrylate (MEA). When the MEA content of the polymers was low (<60 mol %), the εOH value of the water sorbed into polymers in contact with liquid water was equal to that in contact with water vapor. In the higher MEA content (70-100 mol %), on the other hand, the εOH values of the water sorbed into polymers in contact with liquid water were 5-8 times larger than that in contact with water vapor. These results seemed to indicate that the interaction between the primary hydration water around the MEA-containing polymer chain and water molecules surrounding the primarily hydrating water is very weak. Such water with a large εOH value seemed to correspond to "cold-crystallizable" water, which has been observed by DSC as anomalous water other than intermediate and nonfreezable waters. Taking both the experimental results obtained in this work and those thermodynamically obtained previously into consideration, it was strongly suggested that the cold crystallization of water is generated by caging water molecules in a small space by the polymer chains with a small hydration region. The correlation between the εOH value and the blood compatibility of the copolymer was also discussed..
507. Makoto Ide, Takayuki Mori, Ken Ichikawa, Hiromi Kitano, Masaru Tanaka, Akira Mochizuki, Hiroaki Oshiyama, Wataru Mizuno, Structure of water sorbed into poly(MEA-co-HEMA) films as examined by ATR-IR spectroscopy, Langmuir, 10.1021/la020617p, 19, 2, 429-435, 2003.01, The structure of water sorbed into poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and their copolymers (p(MEA/HEMA)) was investigated by attenuated total reflection infrared (ATR-IR) spectroscopy. The extinction coefficient of the OH stretching band of sorbed water (εOH) was calculated from the band area obtained by IR measurement and the amount of sorbed water obtained by thermogravimetric analysis. When the polymers contacted with water vapor (relative humidity = ∼55%), the eon values were quite similar in all polymers. On the other hand, when the polymers contacted with liquid water, the εOH values were drastically changed by the content of 2-methoxyethyl acrylate (MEA). When the MEA content of the polymers was low (<60 mol %), the εOH value of the water sorbed into polymers in contact with liquid water was equal to that in contact with water vapor. In the higher MEA content (70-100 mol %), on the other hand, the εOH values of the water sorbed into polymers in contact with liquid water were 5-8 times larger than that in contact with water vapor. These results seemed to indicate that the interaction between the primary hydration water around the MEA-containing polymer chain and water molecules surrounding the primarily hydrating water is very weak. Such water with a large εOH value seemed to correspond to "cold-crystallizable" water, which has been observed by DSC as anomalous water other than intermediate and nonfreezable waters. Taking both the experimental results obtained in this work and those thermodynamically obtained previously into consideration, it was strongly suggested that the cold crystallization of water is generated by caging water molecules in a small space by the polymer chains with a small hydration region. The correlation between the εOH value and the blood compatibility of the copolymer was also discussed..
508. Masaru Tanaka, Akira Mochizuki, Naoki Ishii, Tadahiro Motomura, Tatsuko Hatakeyama, Study of blood compatibility with poly(2-methoxyethyl acrylate). Relationship between water structure and platelet compatibility in poly(2-methoxyethylacrylate-co-2-hydroxyethylmethacrylate), Biomacromolecules, 10.1021/bm010072y, 3, 1, 36-41, 2002.05, Previously, we reported that poly(2-methoxyethylacrylate) (PMEA) showed excellent blood compatibility and implied that the water structure in PMEA contributed to the blood compatibility. In this study, the relationship between the water structure and the blood compatibility is clarified by studying the influence of the monomer composition of poly(MEA-co-HEMA) on the water structure and the blood compatibility of the copolymers. The water in the polymer was classified into three types: free water, freezing bound water, and nonfreezing water. The polymers with 0-30 mol % of HEMA content had a significant amount of freezing bound water, and the amount decreases greatly when the composition of HEMA exceeded 30 mol %. On the other hand, the amount of other water increased simply with an increase of HEMA content. The evaluation of the platelet compatibility of poly(MEA-co-HEMA) revealed that the adhesion number and the morphological change of platelet on the copolymer surface were least when the HEMA content was 0-20 mol %. These two results strongly suggest that the freezing bound water relates to the platelet compatibility of the polymers..
509. Masaru Tanaka, Akira Mochizuki, Toshifumi Shiroya, Tadahiro Motomura, Kenichi Shimura, Makoto Onishi, Yoshio Okahata, Study on kinetics of early stage protein adsorption on poly(2-methoxyethylacrylate) (PMEA) surface, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/S0927-7757(01)01100-1, 203, 1-3, 195-204, 2002.04, We have already reported that poly(2-methoxyethylacrylate) (PMEA) showed excellent blood compatibility featured by the significantly low adsorption of plasma protein and the low platelet adhesion. In this study, we tried to analyze the adsorption behavior of the plasma proteins (albumin and fibrinogen) on PMEA surface in terms of kinetics in the early stage of the adsorption reaction by using dynamic quartz crystal microbalance (QCM) method. In addition, the conformational changes of the proteins on the polymer surfaces were investigated. It was concluded from the results that the QCM method could be applied to the analysis of the kinetics in such a polymer-protein system. The characteristic of PMEA is that its detachment rate constant k-1, was higher than those from poly(2-hydroxyethylmethacrylate) (PHEMA) and polypropylene (PP) which were used as references. The degree of the conformational changes of the proteins decreases in the following order; PP > PHEMA > > PMEA. This was strongly related to the difference of the detachment rate constant k-1..
510. Masaru Tanaka, Akira Mochizuki, Toshifumi Shiroya, Tadahiro Motomura, Kenichi Shimura, Makoto Onishi, Yoshio Okahata, Study on kinetics of early stage protein adsorption on poly(2-methoxyethylacrylate) (PMEA) surface, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/S0927-7757(01)01100-1, 203, 1-3, 195-204, 2002.04, We have already reported that poly(2-methoxyethylacrylate) (PMEA) showed excellent blood compatibility featured by the significantly low adsorption of plasma protein and the low platelet adhesion. In this study, we tried to analyze the adsorption behavior of the plasma proteins (albumin and fibrinogen) on PMEA surface in terms of kinetics in the early stage of the adsorption reaction by using dynamic quartz crystal microbalance (QCM) method. In addition, the conformational changes of the proteins on the polymer surfaces were investigated. It was concluded from the results that the QCM method could be applied to the analysis of the kinetics in such a polymer-protein system. The characteristic of PMEA is that its detachment rate constant k-1, was higher than those from poly(2-hydroxyethylmethacrylate) (PHEMA) and polypropylene (PP) which were used as references. The degree of the conformational changes of the proteins decreases in the following order; PP > PHEMA > > PMEA. This was strongly related to the difference of the detachment rate constant k-1..
511. Masaru Tanaka, Akira Mochizuki, Naoki Ishii, Tadahiro Motomura, Tatsuko Hatakeyama, Study of blood compatibility with poly(2-methoxyethyl acrylate). Relationship between water structure and platelet compatibility in poly(2-methoxyethylacrylate-co-2-hydroxyethylmethacrylate), Biomacromolecules, 10.1021/bm010072y, 3, 1, 36-41, 2002.02, Previously, we reported that poly(2-methoxyethylacrylate) (PMEA) showed excellent blood compatibility and implied that the water structure in PMEA contributed to the blood compatibility. In this study, the relationship between the water structure and the blood compatibility is clarified by studying the influence of the monomer composition of poly(MEA-co-HEMA) on the water structure and the blood compatibility of the copolymers. The water in the polymer was classified into three types: free water, freezing bound water, and nonfreezing water. The polymers with 0-30 mol % of HEMA content had a significant amount of freezing bound water, and the amount decreases greatly when the composition of HEMA exceeded 30 mol %. On the other hand, the amount of other water increased simply with an increase of HEMA content. The evaluation of the platelet compatibility of poly(MEA-co-HEMA) revealed that the adhesion number and the morphological change of platelet on the copolymer surface were least when the HEMA content was 0-20 mol %. These two results strongly suggest that the freezing bound water relates to the platelet compatibility of the polymers..
512. Masaru Tanaka, Akira Mochizuki, Tadahiro Motomura, Kenichi Shimura, Makoto Onishi, Yoshio Okahata, In situ studies on protein adsorption onto a poly(2-methoxyethylacrylate) surface by a quartz crystal microbalance, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/S0927-7757(01)00682-3, 193, 1-3, 145-152, 2001.12, We have reported that poly(2-methoxyethylacrylate) (PMEA) showed excellent blood compatibility though it had a simple chemical structure, and have been making efforts to clarify the reason for the blood compatibility. It is well-known that the adsorption behavior of the protein affects the compatibility. Therefore, the adsorption behaviors of bovine serum albumin (BSA) and human fibrinogen onto the surfaces of PMEA, poly(2-hydroxyethyl methacrylate) (PHEMA) and polypropylene (PP) were investigated by using a quartz crystal microbalance (QCM), where PHEMA and PP were selected as the representatives of hydrophilic and hydrophobic polymers, respectively. Both proteins were observed to adsorb onto all the polymer surfaces according to Langmuir's adsorption isotherm. The maximum adsorption amounts and the apparent association constants of the proteins for PMEA obtained from the isotherm were lower than those for PHEMA and PP. These results suggest that the interaction between PMEA and the proteins is weaker than the interaction with PP and PHEMA..
513. Masaru Tanaka, Akira Mochizuki, Tadahiro Motomura, Kenichi Shimura, Makoto Onishi, Yoshio Okahata, In situ studies on protein adsorption onto a poly(2-methoxyethylacrylate) surface by a quartz crystal microbalance, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 10.1016/S0927-7757(01)00682-3, 193, 1-3, 145-152, 2001.12, We have reported that poly(2-methoxyethylacrylate) (PMEA) showed excellent blood compatibility though it had a simple chemical structure, and have been making efforts to clarify the reason for the blood compatibility. It is well-known that the adsorption behavior of the protein affects the compatibility. Therefore, the adsorption behaviors of bovine serum albumin (BSA) and human fibrinogen onto the surfaces of PMEA, poly(2-hydroxyethyl methacrylate) (PHEMA) and polypropylene (PP) were investigated by using a quartz crystal microbalance (QCM), where PHEMA and PP were selected as the representatives of hydrophilic and hydrophobic polymers, respectively. Both proteins were observed to adsorb onto all the polymer surfaces according to Langmuir's adsorption isotherm. The maximum adsorption amounts and the apparent association constants of the proteins for PMEA obtained from the isotherm were lower than those for PHEMA and PP. These results suggest that the interaction between PMEA and the proteins is weaker than the interaction with PP and PHEMA..
514. Hiromi Kitano, Ken Ichikawa, Mitsuhiro Fukuda, Akira Mochizuki, Masaru Tanaka, The structure of water sorbed to polymethoxyethylacrylate film as examined by FT-IR spectroscopy, Journal of Colloid and Interface Science, 10.1006/jcis.2001.7785, 242, 1, 133-140, 2001.10, The state of sorbed water and sorbing processes of water to four kinds of vinyl polymer films were studied by FT-IR. The O-H stretching band of water sorbed to the films gradually increased on contact with a water vapor of 50% relative humidity at 25°C and leveled off. The profile of the O-H stretching band of sorbed water changed with chemical structure of the polymers. Water sorbed to poly(methoxyethylacrylate) (PMEA), for example, had a sharp and large peak at 3625 cm-1 and a neighboring broader peak with a long slope in the lower frequency region, which resembled the summation of the peaks for water sorbed to poly(methylmethacrylate) (PMMA, two sharp peaks) and poly(vinylmethylether) (PVME, two broader peaks in the lower frequency region) films. The peak frequencies of the sorbed water were consistent with the calculated values for water hydrogen-bonded to the model compounds by using a hybrid density functional method. When water droplets were put on the polymer film, furthermore, the O-H stretching band of water within the polymer matrix was obtained using an attenuated total reflection technique. An O-H profile similar to that of free water was observed for water incorporated within the matrix of PMEA and PVME films, whereas those profiles within the matrix of poly(2-hydroxyethylmethacrylate) (PHEMA) and PMMA films were largely different from that of free water. This might be in accordance with the difference in biocompatibility of four kinds of polymeric materials. The diffusion coefficients of water vapor in these polymer films were also determined by the time-resolved FT-IR method..
515. Hiromi Kitano, Ken Ichikawa, Mitsuhiro Fukuda, Akira Mochizuki, Masaru Tanaka, The structure of water sorbed to polymethoxyethylacrylate film as examined by FT-IR spectroscopy, Journal of Colloid And Interface Science, 10.1006/jcis.2001.7785, 242, 1, 133-140, 2001.10, The state of sorbed water and sorbing processes of water to four kinds of vinyl polymer films were studied by FT-IR. The O-H stretching band of water sorbed to the films gradually increased on contact with a water vapor of 50% relative humidity at 25°C and leveled off. The profile of the O-H stretching band of sorbed water changed with chemical structure of the polymers. Water sorbed to poly(methoxyethylacrylate) (PMEA), for example, had a sharp and large peak at 3625 cm-1 and a neighboring broader peak with a long slope in the lower frequency region, which resembled the summation of the peaks for water sorbed to poly(methylmethacrylate) (PMMA, two sharp peaks) and poly(vinylmethylether) (PVME, two broader peaks in the lower frequency region) films. The peak frequencies of the sorbed water were consistent with the calculated values for water hydrogen-bonded to the model compounds by using a hybrid density functional method. When water droplets were put on the polymer film, furthermore, the O-H stretching band of water within the polymer matrix was obtained using an attenuated total reflection technique. An O-H profile similar to that of free water was observed for water incorporated within the matrix of PMEA and PVME films, whereas those profiles within the matrix of poly(2-hydroxyethylmethacrylate) (PHEMA) and PMMA films were largely different from that of free water. This might be in accordance with the difference in biocompatibility of four kinds of polymeric materials. The diffusion coefficients of water vapor in these polymer films were also determined by the time-resolved FT-IR method..
516. Ken Ichikawa, Takayuki Mori, Hiromi Kitano, Mitsuhiro Fukuda, Akira Mochizuki, Masaru Tanaka, Fourier transform infrared study on the sorption of water to various kinds of polymer thin films, Journal of Polymer Science, Part B: Polymer Physics, 10.1002/polb.1191, 39, 18, 2175-2182, 2001.09, The state of sorbed water and the sorbing processes of water to various polymer thin films were studied with Fourier transform infrared (FTIR) spectroscopy. To prepare the polymer films, we used poly(ethylene glycol)s of different molecular weights and various kinds of vinyl polymers, such as poly(2-methoxyethyl acrylate). The O-H stretching band of water sorbed in the films increased gradually on contact with water vapor at 50% relative humidity and leveled off. When O-H stretching bands of water sorbed to polymer films were compared, the peak positions and profiles of water sorbed to the polymeric materials with the same hydrogen-bonding site were similar. A hybrid density-functional method supported the assignment of the peaks. Furthermore, the diffusion coefficient (D) of water vapor in the polymer films was estimated by time-resolved measurements of the sorbed water at the very initial stage (0-830 s). It was clearly shown that the D values of water vapor in the polymer materials with a strong hydrogen-bonding site were smaller than those in hydrophobic polymers. The usefulness of the FTIR technique to investigate water sorption to polymer materials was definitely demonstrated..
517. Ken Ichikawa, Takayuki Mori, Hiromi Kitano, Mitsuhiro Fukuda, Akira Mochizuki, Masaru Tanaka, Fourier transform infrared study on the sorption of water to various kinds of polymer thin films, Journal of Polymer Science, Part B: Polymer Physics, 10.1002/polb.1191, 39, 18, 2175-2182, 2001.09, The state of sorbed water and the sorbing processes of water to various polymer thin films were studied with Fourier transform infrared (FTIR) spectroscopy. To prepare the polymer films, we used poly(ethylene glycol)s of different molecular weights and various kinds of vinyl polymers, such as poly(2-methoxyethyl acrylate). The O-H stretching band of water sorbed in the films increased gradually on contact with water vapor at 50% relative humidity and leveled off. When O-H stretching bands of water sorbed to polymer films were compared, the peak positions and profiles of water sorbed to the polymeric materials with the same hydrogen-bonding site were similar. A hybrid density-functional method supported the assignment of the peaks. Furthermore, the diffusion coefficient (D) of water vapor in the polymer films was estimated by time-resolved measurements of the sorbed water at the very initial stage (0-830 s). It was clearly shown that the D values of water vapor in the polymer materials with a strong hydrogen-bonding site were smaller than those in hydrophobic polymers. The usefulness of the FTIR technique to investigate water sorption to polymer materials was definitely demonstrated..
518. Masaru Tanaka, Tadahiro Motomura, Naoki Ishii, Kenichi Shimura, Makoto Onishi, Akira Mochizuki, Tatsuko Hatakeyama, Cold crystallization of water in hydrated poly(2-methoxyethyl acrylate) (PMEA), Polymer International, 10.1002/1097-0126(200012)49:12<1709::AID-PI601>3.0.CO;2-L, 49, 12, 1709-1713, 2000.12, The structure of water associated with poly(2-methoxyethyl acrylate) (PMEA), which is known to exhibit excellent blood compatibility, has been investigated using differential scanning calorimetry (DSC). The total equilibrium water content (EWC) of PMEA was 9.0wt%. Water in the PMEA could be classified into three types: non-freezing, freezing-bound and free water. Cold crystallization of water was clearly observed at about -42°C on heating when the water content was more than 3.0wt%. Cold crystallization is attributed to the phase transition from the amorphous ice to the crystal ice in PMEA. The relative proportions of freezing-bound water at the EWC is 48% of all the water in hydrated PMEA..
519. Masaru Tanaka, T. Motomura, M. Kawada, T. Anzai, Y. Kasori, K. Shimura, M. Onishi, A. Mochizuki, Y. Okahata, A new blood-compatible surface prepared by poly(2-methoxyethylacrylate) (PMEA) coating - Protein adsorption on PMEA surface, Japanese Journal of Artificial Organs, 29, 1, 209-216, 2000.12, Poly(2-methoxyethylacrylate) (PMEA) surface shows good blood compatibility with respect to the coagulation, complement, and platelet systems when compared with other polymer surfaces. To clarify the reasons for this good compatibility, the amount of the plasma protein adsorbed onto PMEA and its secondary structure were investigated. Poly (2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogs were used as references. The amount of protein adsorbed onto PMEA was very small, and close to that adsorbed onto PHEMA. Circular dichroism (CD) spectroscopy revealed that the conformations of the proteins adsorbed onto PHEMA changed considerably, while those of the proteins adsorbed onto PMEA differed only slightly from the native one. Based on the quartz crystal microbalance (QCM) measurement, we estimated the binding constant and association and dissociation rate constants of the proteins adsorbed onto the polymer surfaces. These results suggested that the excellent blood compatibility of PMEA is closely related to the low denaturation and the high dissociation rate constant of the proteins adsorbed onto PMEA. In addition, the structure of water in the hydrated PMEA was investigated using differential scanning calorimetry (DSC). Cold crystallization of water in the heating process was clearly observed at -42°C. This cold crystallization is interpreted as the phase transition from the amorphous ice to the crystal ice that belongs to the freeze-bound water in PMEA. We believe that this feature of the water structure is related to blood compatibility..
520. Masaru Tanaka, Tadahiro Motomura, Naoki Ishii, Kenichi Shimura, Makoto Onishi, Akira Mochizuki, Tatsuko Hatakeyama, Cold crystallization of water in hydrated poly(2-methoxyethyl acrylate) (PMEA), Polymer International, 10.1002/1097-0126(200012)49:12<1709::AID-PI601>3.0.CO;2-L, 49, 12, 1709-1713, 2000.12, The structure of water associated with poly(2-methoxyethyl acrylate) (PMEA), which is known to exhibit excellent blood compatibility, has been investigated using differential scanning calorimetry (DSC). The total equilibrium water content (EWC) of PMEA was 9.0wt%. Water in the PMEA could be classified into three types: non-freezing, freezing-bound and free water. Cold crystallization of water was clearly observed at about -42°C on heating when the water content was more than 3.0wt%. Cold crystallization is attributed to the phase transition from the amorphous ice to the crystal ice in PMEA. The relative proportions of freezing-bound water at the EWC is 48% of all the water in hydrated PMEA..
521. M Tanaka, T Motomura, N Ishii, K Shimura, M Onishi, A Mochizuki, T Hatakeyama, Cold crystallization of water in hydrated poly(2-methoxyethyl acrylate) (PMEA), POLYMER INTERNATIONAL, 10.1002/1097-0126(200012)49:12<1709::AID-PI601>3.0.CO;2-L, 49, 12, 1709-1713, 2000.12, The structure of water associated with poly(2-methoxyethyl acrylate) (PMEA), which is known to exhibit excellent blood compatibility, has been investigated using differential scanning calorimetry (DSC). The total equilibrium water content (EWC) of PMEA was 9.0wt%. Water in the PMEA could be classified into three types: non-freezing, freezing-bound and free water. Cold crystallization of water was clearly observed at about -42 degreesC on heating when the water content was more than 3.0wt%. Cold crystallization is attributed to the phase transition from the amorphous ice to the crystal ice in PMEA. The relative proportions of freezing-bound water at the EWC is 48 % of all the water in hydrated PMEA. (C) 2000 Society of Chemical Industry..
522. Masaru Tanaka, Tadahiro Motomura, Miho Kawada, Takao Anzai, Kasori Yuu Kasori, Toshifumi Shiroya, Kenichi Shimura, Makoto Onishi, Mochizuki Akira Mochizuki, Blood compatible aspects of poly(2-methoxyethylacrylate) (PMEA)-relationship between protein adsorption and platelet adhesion on PMEA surface, Biomaterials, 10.1016/S0142-9612(00)00031-4, 21, 14, 1471-1481, 2000.07, Platelet adhesion and spreading is suppressed when a poly(2-methoxyethylacrylate) (PMEA) surface is used, compared with other polymer surfaces. To clarify the reason for this suppression, the relationship among the amount of the plasma protein adsorbed onto PMEA, its secondary structure and platelet adhesion was investigated. Poly(2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogous were used as references. The amount of protein adsorbed onto PMEA was very low and similar to that absorbed onto PHEMA. Circular dichroism (CD) spectroscopy was applied to examine changes in the secondary structure of the proteins after adsorption onto the polymer surface. The conformation of the proteins adsorbed onto PHEMA changed considerably, but that of proteins adsorbed onto PMEA differed only a little from the native one. These results suggest that low platelet adhesion and spreading are closely related to the low degree of the denaturation of the protein adsorbed onto PMEA. PMEA could be developed as a promising material to produce a useful blood-contacting surface for medical devices. Copyright (C) 2000 Elsevier Science B.V..
523. Masaru Tanaka, Tadahiro Motomura, Miho Kawada, Takao Anzai, Kasori Yuu Kasori, Toshifumi Shiroya, Kenichi Shimura, Makoto Onishi, Mochizuki Akira Mochizuki, Blood compatible aspects of poly(2-methoxyethylacrylate) (PMEA)-relationship between protein adsorption and platelet adhesion on PMEA surface, Biomaterials, 10.1016/S0142-9612(00)00031-4, 21, 14, 1471-1481, 2000.07, Platelet adhesion and spreading is suppressed when a poly(2-methoxyethylacrylate) (PMEA) surface is used, compared with other polymer surfaces. To clarify the reason for this suppression, the relationship among the amount of the plasma protein adsorbed onto PMEA, its secondary structure and platelet adhesion was investigated. Poly(2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogous were used as references. The amount of protein adsorbed onto PMEA was very low and similar to that absorbed onto PHEMA. Circular dichroism (CD) spectroscopy was applied to examine changes in the secondary structure of the proteins after adsorption onto the polymer surface. The conformation of the proteins adsorbed onto PHEMA changed considerably, but that of proteins adsorbed onto PMEA differed only a little from the native one. These results suggest that low platelet adhesion and spreading are closely related to the low degree of the denaturation of the protein adsorbed onto PMEA. PMEA could be developed as a promising material to produce a useful blood-contacting surface for medical devices. Copyright (C) 2000 Elsevier Science B.V..
524. M Tanaka, T Motomura, M Kawada, T Anzai, Y Kasori, T Shiroya, K Shimura, M Onishi, A Mochizuki, Blood compatible aspects of poly(2-methoxyethylacrylate) (PMEA) - relationship between protein adsorption and platelet adhesion on PMEA surface, BIOMATERIALS, 21, 14, 1471-1481, 2000.07, Platelet adhesion and spreading is suppressed when a poly(2-methoxyethylacrylate) (PMEA) surface is used, compared with other polymer surfaces. To clarify the reason for this suppression, the relationship among the amount of the plasma protein adsorbed onto PMEA, its secondary structure and platelet adhesion was investigated. Poly(2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogous were used as references. The amount of protein adsorbed onto PMEA was very low and similar to that absorbed onto PHEMA. Circular dichroism (CD) spectroscopy was applied to examine changes in the secondary structure of the proteins after adsorption onto the polymer surface. The conformation of the proteins adsorbed onto PHEMA changed considerably, but that of proteins adsorbed onto PMEA differed only a little from the native one. These results suggest that low platelet adhesion and spreading are closely related to the low degree of the denaturation of the protein adsorbed onto PMEA. PMEA could be developed as a promising material to produce a useful blood-contacting surface for medical devices. (C) 2000 Elsevier Science Ltd. Ail rights reserved..
525. Masaru Tanaka, T. Motomura, M. Kawada, T. Anzai, Y. Kasori, K. Shimura, M. Onishi, A. Mochizuki, Y. Okahata, A new blood-compatible surface prepared by poly(2-methoxyethylacrylate) (PMEA) coating - Protein adsorption on PMEA surface, Japanese Journal of Artificial Organs, 29, 1, 209-216, 2000.05, Poly(2-methoxyethylacrylate) (PMEA) surface shows good blood compatibility with respect to the coagulation, complement, and platelet systems when compared with other polymer surfaces. To clarify the reasons for this good compatibility, the amount of the plasma protein adsorbed onto PMEA and its secondary structure were investigated. Poly (2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogs were used as references. The amount of protein adsorbed onto PMEA was very small, and close to that adsorbed onto PHEMA. Circular dichroism (CD) spectroscopy revealed that the conformations of the proteins adsorbed onto PHEMA changed considerably, while those of the proteins adsorbed onto PMEA differed only slightly from the native one. Based on the quartz crystal microbalance (QCM) measurement, we estimated the binding constant and association and dissociation rate constants of the proteins adsorbed onto the polymer surfaces. These results suggested that the excellent blood compatibility of PMEA is closely related to the low denaturation and the high dissociation rate constant of the proteins adsorbed onto PMEA. In addition, the structure of water in the hydrated PMEA was investigated using differential scanning calorimetry (DSC). Cold crystallization of water in the heating process was clearly observed at -42°C. This cold crystallization is interpreted as the phase transition from the amorphous ice to the crystal ice that belongs to the freeze-bound water in PMEA. We believe that this feature of the water structure is related to blood compatibility..
526. M. Shimomura, F. Nakamura, K. Ijiro, H. Taketsuna, Masaru Tanaka, H. Nakamura, K. Hasebe, Two-dimensional DNA-mimetic molecular organizations at the air-water interface, Journal of the American Chemical Society, 10.1021/ja962847u, 119, 9, 2341-2342, 1997.04.
527. M Shimomura, F Nakamura, K Ijiro, H Taketsuna, M Tanaka, H Nakamura, K Hasebe, Two-dimensional DNA-mimetic molecular organizations at the air-water interface, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/ja962847u, 119, 9, 2341-2342, 1997.03.
528. M. Shimomura, F. Nakamura, K. Ijiro, H. Taketsuna, M. Tanaka, H. Nakamura, K. Hasebe, Two-dimensional DNA-mimetic molecular organizations at the air-water interface, Journal of the American Chemical Society, 10.1021/ja962847u, 119, 9, 2341-2342, 1997.01.
529. M. Shimomura, F. Nakamura, K. Ijiro, H. Taketsuna, Masaru Tanaka, H. Nakamura, K. Hasebe, Chiral crystal formation of octadecylcytosine monolayer by complementary base paring, Thin Solid Films, 10.1016/S0040-6090(95)08422-3, 284-285, 691-693, 1996.09, A stable monolayer assembly of octadecylcytosine, which can not be spread as a monolayer on pure water subphase, was formed when a small amount of guanosine was added to the water subphase. Spiral shaped two-dimensional crystal domains of the monolayer were observed by a fluorescence microscope. Fourier transform IR spectrum of the deposited monolayer prepared on the guanosine subphase strongly suggests complementary base pairing at the interface..
530. Kuniharu Ijiro, Masatsugu Shimomura, Masaru Tanaka, Hiroshi Nakamura, Kiyoshi Hasebe, DNA monolayers complexed with amphiphilic intercalator at the air-water interface, Thin Solid Films, 10.1016/S0040-6090(95)08445-2, 284-285, 780-783, 1996.09, The interaction of a newly synthesized cationic intercalator amphiphile C18AO into double-stranded DNAs at the air-water interface was investigated. Polyion complex monolayers consisting of DNAs and cationic amphiphiles were prepared. Pressure-area isotherms, fluorescence measurements, Fourier transform infrared-reflection-absorption spectroscopy and quartz crystal microbalance measurements suggest that C18AO molecules can be intercalated into base-pairs of DNAs to form densely packed two-dimensional DNA arrays at the air-water interface..
531. M. Shimomura, F. Nakamura, K. Ijiro, H. Taketsuna, M. Tanaka, H. Nakamura, K. Hasebe, Chiral crystal formation of octadecylcytosine monolayer by complementary base paring, Thin Solid Films, 10.1016/S0040-6090(95)08422-3, 284-285, 691-693, 1996.09, A stable monolayer assembly of octadecylcytosine, which can not be spread as a monolayer on pure water subphase, was formed when a small amount of guanosine was added to the water subphase. Spiral shaped two-dimensional crystal domains of the monolayer were observed by a fluorescence microscope. Fourier transform IR spectrum of the deposited monolayer prepared on the guanosine subphase strongly suggests complementary base pairing at the interface..
532. Kuniharu Ijiro, Masatsugu Shimomura, Masaru Tanaka, Hiroshi Nakamura, Kiyoshi Hasebe, DNA monolayers complexed with amphiphilic intercalator at the air-water interface, Thin Solid Films, 10.1016/S0040-6090(95)08445-2, 284-285, 780-783, 1996.09, The interaction of a newly synthesized cationic intercalator amphiphile C18AO into double-stranded DNAs at the air-water interface was investigated. Polyion complex monolayers consisting of DNAs and cationic amphiphiles were prepared. Pressure-area isotherms, fluorescence measurements, Fourier transform infrared-reflection-absorption spectroscopy and quartz crystal microbalance measurements suggest that C18AO molecules can be intercalated into base-pairs of DNAs to form densely packed two-dimensional DNA arrays at the air-water interface..
533. M Shimomura, F Nakamura, K Ijiro, H Taketsuna, M Tanaka, H Nakamura, K Hasebe, Chiral crystal formation of octadecylcytosine monolayer by complementary base paring, THIN SOLID FILMS, 10.1016/S0040-6090(95)08422-3, 284, 691-693, 1996.09, A stable monolayer assembly of octadecylcytosine, which can not be spread as a monolayer on pure water subphase, was formed when a small amount of guanosine was added to the water subphase. Spiral shaped two-dimensional crystal domains of the monolayer were observed by a fluorescence microscope. Fourier transform IR spectrum of the deposited monolayer prepared on the guanosine subphase strongly suggests complementary base pairing at the interface..
534. K Ijiro, M Shimomura, M Tanaka, H Nakamura, K Hasebe, DNA monolayers complexed with amphiphilic intercalator at the air-water interface, THIN SOLID FILMS, 10.1016/S0040-6090(95)08445-2, 284, 780-783, 1996.09, The interaction of a newly synthesized cationic intercalator amphiphile C(18)AO into double-stranded DNAs at the air-water interface was investigated. Polyion complex monolayers consisting of DNAs and cationic amphiphiles were prepared, Pressure-area isotherms. fluorescence measurements, Fourier transform infrared-reflection-absorption spectroscopy and quartz crystal microbalance measurements suggest that C(18)AO molecules can be intercalated into base-pairs of DNAs to form densely packed two-dimensional DNA arrays at the air-water interface..