Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kidoaki Satoru Last modified date:2024.06.03

Professor / Research Field of Biomedical and Biphysical Chemistry / Department of Applied Molecular Chemistry / Institute for Materials Chemistry and Engineering

1. ST. Lee, T. Kuboki, S. Kidoaki, Y. Aida, Y Arima*, K. Tamada, A plasmonic metasurface reveals differential motility of breast cancer cell lines at initial phase of adhesion, 238, 113876, 2024.03.
2. S. Masaike, S. Kidoaki, Cell Adhesion Control through Culture Substrate Design: Considerations for Incorporating Molecular Mechanisms of Adhesion Mechanics into Biomaterials Engineering, Journal of Biomechanical Science and Engineering, 18, 23-00358, 2024.02.
3. H. Miyoshi*, M, Yamazaki, H. Fujie, S. Kidoaki, Guideline for design of substrate stiffness for mesenchymal stem cell culture based on heterogeneity of YAP and RUNX2 responses, Biophysics and Physicobiology, 2023.02.
4. H. Katsuta, S. Okuda, K. Nagayama, H. Machiyama, S. Kidoaki, M. Kato, M. Sokabe, T. Miyata, H. Hirata, Actin crosslinking by α-actinin averts viscous dissipation of myosin force transmission in stress fibers, which ensures traction force exertion and cell migration, i Science, 2023.02.
5. S. Masaike, Y. Tsuji, and S.Kidoaki, Local pH mapping in the cell adhesion nano-interfaces on a pH-responsive fluorescence-dye-immobilized substrate, Anal. Sci., 39, 347–355 (2023), 2023.03.
6. H. Ebata and S.Kidoaki,, Interplay among cell migration, shaping, and traction force on a matrix with cell-scale stiffness heterogeneity, Biophysics and Physicobiology, Volume 19 Article ID: e190036 , 2022.12.
7. Sayaka Masaike, Saori Sasaki, Hiroyuki Ebata, Kosuke Moriyama, Satoru Kidoaki, Adhesive-ligand-independent cell-shaping controlled by the lateral deformability of a condensed polymer matrix, POLYMER JOURNAL, 10.1038/s41428-021-00577-w, 2021.11, Cell adhesion on biomaterial surfaces has been extensively studied from the perspective of the adsorption properties of adhesive ligands, while recent research on mechanobiology has been revealing a critical role of the mechanical properties of the extracellular milieu in the control of cell adhesion, such as the stiffness and viscoelasticity of the matrix. Although the effects of the lateral mobility of an adhesive ligand have been intensively investigated in a model substrate with water-soluble polymer layers, less is known about those in the setting of lateral deformability of hydrophobic condensed polymer layers. In this study, to help clarify this issue, we used PNIPAAm-grafted substrates with a well-controlled degree of graft-polymerization (DGP) as a typical hydrophobic condensed polymer surface at a cell culture temperature of 37 degrees C. We observed a clear negative correlation between cell spreading and DGP of PNIPAAm regardless of the amount of fibronectin adsorbed on the substrates, which was found to be attributable to the lateral deformability of a condensed PNIPAAm layer based on lateral force microscopic analysis. The surface-lateral-deformation-induced modulation in stability and maturation of focal adhesion of the cells is discussed in relation to the matrix-strain-induced alteration of the density distribution of adsorbed adhesive ligands..
8. H. Ebata and S. Kidoaki, Avoiding tensional equilibrium in cells migrating on a matrix with cell-scale stiffness-heterogeneity, Biomaterials, 120860, 2021., 2021.05.
9. S. Masuda,T. Kuboki, S. Kidoaki, S-T. Lee, S. Ryuzaki, K. Okamoto, Y. Arima, K. Tamada, High axial and lateral resolution on self-assembled gold nanoparticle metasurfaces for live-cell imaging, ACS Appl. Nano Mater., 3, 11, 11135-11142, 2020.10.
10. M. Yamazaki, S. Kidoaki, H. Fujie, H. Miyoshi, Designing elastic modulus of cell culture substrate to regulate YAP and RUNX2 localization for controlling differentiation of human mesenchymal stem cells, Anal. Sci., in press, 2020.10.
11. T. Fukuyama, H. Ebata, Y. Kondo, S. Kidoaki, K. Aoki, Y. T. Maeda, Why epithelial cells collectively move against a traveling signal wave, arXiv, 2008.12955, 2020.08.
12. Hiroyuki Ebata, Kousuke Moriyama, Thasaneeya Kuboki, Satoru Kidoaki, General cellular durotaxis induced with cell-scale heterogeneity of matrix-elasticity, Biomaterials, 10.1016/j.biomaterials.2019.119647, 230, 2020.02, Stiffness-gradient-induced cellular taxis, so-called durotaxis, has been extensively studied on a substrate with a single broad or steep stiffness gradient. However, in actual living tissues, cells should sense cell-scaled heterogeneous elasticity distribution in the extracellular matrix. In this study, to clarify the effect of the cell-scale heterogeneity of matrix-elasticity on durotaxis, we examined the motility of different types of cells on microelastically-striped patterned gels with different cell-sized widths. We found that cells accumulated in stiff regions with specific width on cell-type-dependency, even when a stiffness gradient is too small to induce usual durotaxis with a monotonic stiffness gradient. Fibroblast cells accumulated in a wide stiff region of multicellular size, while mesenchymal stem cells localized in a narrow stiff region of single-cell size. It was revealed that durotactic activity is critically affected not only with the cell type but also with the cell-scale heterogeneity of matrix-elasticity. Based on the shape-fluctuation-based analysis of cell migration, the dynamics of the pseudopodia were found to play a key role in determining the behaviors of general durotaxis. Our results suggest that design of cell-scale heterogeneity of matrix-elasticity is pivotal in controlling directional cell migration, the spontaneous cell-patterning, and development of the tissue on the biomaterials surfaces..
13. D. Huang and S. Kidoaki, Stiffness-optimized drug-loaded matrix for selective capture and elimination of cancer cells, J. Drug Deliv. Sci. Technol., 55, 10414, 2020.02.
14. T. Kuboki, H. Ebata, T. Matsuda, Y. Arai, T. Nagai, S. Kidoaki, Hierarchical development of motile polarity in durotactic cells just crossing an elasticity boundary, Cell Struct. Funct., 45, 33-43, 2020.02.
15. Kei Sugihara, Saori Sasaki, Akiyoshi Uemura, Satoru Kidoaki, Takashi Miura, Mechanisms of endothelial cell coverage by pericytes
computational modelling of cell wrapping and in vitro experiments, Journal of the Royal Society, Interface, 10.1098/rsif.2019.0739, 17, 162, 2020.01, Pericytes (PCs) wrap around endothelial cells (ECs) and perform diverse functions in physiological and pathological processes. Although molecular interactions between ECs and PCs have been extensively studied, the morphological processes at the cellular level and their underlying mechanisms have remained elusive. In this study, using a simple cellular Potts model, we explored the mechanisms for EC wrapping by PCs. Based on the observed in vitro cell wrapping in three-dimensional PC-EC coculture, the model identified four putative contributing factors: preferential adhesion of PCs to the extracellular matrix (ECM), strong cell-cell adhesion, PC surface softness and larger PC size. While cell-cell adhesion can contribute to the prevention of cell segregation and the degree of cell wrapping, it cannot determine the orientation of cell wrapping alone. While atomic force microscopy revealed that PCs have a larger Young's modulus than ECs, the experimental analyses supported preferential ECM adhesion and size asymmetry. We also formulated the corresponding energy minimization problem and numerically solved this problem for specific cases. These results give biological insights into the role of PC-ECM adhesion in PC coverage. The modelling framework presented here should also be applicable to other cell wrapping phenomena observed in vivo..
16. Saori Sasaki, Satoru Kidoaki, Precise design of microwrinkles through the independent regulation of elasticity on the surface and in the bulk of soft hydrogels, Polymer Journal, 10.1038/s41428-019-0299-8, 2019.12, Abstract: It is still difficult to precisely control microscopic wrinkles on the surface of functional materials, especially biomimetic soft hydrogels with an elastic modulus lower than 100 kPa. This is due to the difficulty in realizing the systematic and independent regulation of elasticity on the top surface and in the bulk of hydrogels, which is essential for the generation of surface microwrinkles. To overcome this problem, using a two-step photocrosslinking process with VIS and UV irradiation of a photocurable gelatinous sol, we developed a method for independently regulating the elastic modulus on the surface and in the bulk to obtain wrinkles on a biomimetic soft gel. Photocurable gelatin was first irradiated and crosslinked with VIS light in the presence of the water-soluble radical generator sulfonyl camphorquinone, which is effective in forming thick bulk gels. Next, the top surface of these precrosslinked gels was irradiated with UV light in the presence of surface-coated water-insoluble camphorquinone. As a result, this two-step photocrosslinking process enabled to independently control the elastic moduli of the surface and the bulk lower than 100 kPa and to generate several-micron-scale wrinkles on the soft hydrogel surface..
17. Daoxiang Huang, Yu Nakamura, Aya Ogata, Satoru Kidoaki, Characterization of 3D matrix conditions for cancer cell migration with elasticity/porosity-independent tunable microfiber gels, Polymer Journal, 10.1038/s41428-019-0283-3, 2019.10, The mechanics and architectures of the extracellular matrix (ECM) critically influence 3D cell migration processes, such as cancer cell invasion and metastasis. Understanding the roles of mechanical and structural factors in the ECM could provide an essential basis for cancer treatment. However, it is generally difficult to independently characterize these roles due to the coupled changes in these factors in conventional ECM model systems. In this study, to solve this problem, we developed elasticity/porosity-tunable electrospun fibrous gel matrices composed of photocrosslinked gelatinous microfibers (nanometer-scale-crosslinked chemical gels) with well-regulated bonding (tens-of-micron-scale fiber-bonded gels). This system enables independent modulation of microscopic fiber elasticity and matrix porosity, i.e., the mechanical and structural conditions of the ECM. The elasticity of fibers was tuned with photocrosslinking conditions. The porosity was regulated by changing the degree of interfiber bonding. The influences of these factors of the fibrous gel matrix on the motility of MDA-MB-231 tumorigenic cells and MCF-10A nontumorigenic cells were quantitatively investigated. MDA-MB-231 cells showed the highest degree of MMP-independent invasion into the matrix composed of fibers with a Young’s modulus of 20 kPa and a low degree of interfiber bonding, while MCF-10A cells did not show invasive behavior under the same matrix conditions..
18. Satoru Kidoaki, Frustrated differentiation of mesenchymal stem cells, Biophysical Reviews, 10.1007/s12551-019-00528-z, 11, 3, 377-382, 2019.06, Mesenchymal stem cells (MSCs) are one of the most useful cell resources for clinical application in regenerative medicine. However, standardization and quality assurance of MSCs are still essential problems because the stemness of MSCs depends on such factors as the collection method, individual differences associated with the source, and cell culture history. As such, the establishment of culture techniques which assure the stemness of MSCs is of vital importance. One important factor affecting MSCs during culture is the effect of the mechanobiological memory of cultured MSCs built up by their encounter with particular mechanical properties of the extracellular mechanical milieu. How can we guarantee that MSCs will remain in an undifferentiated state? Procedures capable of eliminating effects related to the history of the mechanical dose for cultured MSCs are required. For this problem, we have tried to establish the design of microelastically patterned cell-culture matrix which can effectively induce mechanical oscillations during the period of nomadic migration of cells among different regions of the matrix. We have previously observed before that the MSCs exposed to such a growth regimen during nomadic culture keep their undifferentiated state—with this maintenance of stemness believed due to lack of a particular regular mechanical dosage that is likely to determine a specific lineage. We have termed this situation as “frustrated differentiation”. In this minireview, I introduce the concept of frustrated differentiation of MSCs and show possibility of purposeful regulation of this phenomenon..
19. Misato Iwashita, Hatsumi Ohta, Takahiro Fujisawa, Minyoung Cho, Makoto Ikeya, Satoru Kidoaki, Yoichi Kosodo, Brain-stiffness-mimicking tilapia collagen gel promotes the induction of dorsal cortical neurons from human pluripotent stem cells, Scientific reports, 10.1038/s41598-018-38395-5, 9, 1, 2018.12, The mechanical properties of the extracellular microenvironment, including its stiffness, play a crucial role in stem cell fate determination. Although previous studies have demonstrated that the developing brain exhibits spatiotemporal diversity in stiffness, it remains unclear how stiffness regulates stem cell fate towards specific neural lineages. Here, we established a culture substrate that reproduces the stiffness of brain tissue using tilapia collagen for in vitro reconstitution assays. By adding crosslinkers, we obtained gels that are similar in stiffness to living brain tissue (150–1500 Pa). We further examined the capability of the gels serving as a substrate for stem cell culture and the effect of stiffness on neural lineage differentiation using human iPS cells. Surprisingly, exposure to gels with a stiffness of approximately 1500 Pa during the early period of neural induction promoted the production of dorsal cortical neurons. These findings suggest that brain-stiffness-mimicking gel has the potential to determine the terminal neural subtype. Taken together, the crosslinked tilapia collagen gel is expected to be useful in various reconstitution assays that can be used to explore the role of stiffness in neurogenesis and neural functions. The enhanced production of dorsal cortical neurons may also provide considerable advantages for neural regenerative applications..
20. Atsushi Sakai, Naomi Hiro-oka, Saori Sasaki, Satoru Kidoaki, Miho Yanagisawa, Lipid membrane effect on the elasticity of gelatin microgel prepared inside lipid microdroplets, Nihon Reoroji Gakkaishi, 10.1678/rheology.47.55, 47, 2, 55-59, 2019.01, In a previous study (Sakai A., et al., ACS Cent. Sci., 4, 477 (2018)), a spherical microgel of gelatin prepared inside a lipid droplet was reported to have a higher surface elasticity than the bulk gel. In this study, we investigate the role of contact or lack of contact between gelatin and the lipid membrane as well as the micrometric confinement to isolate the dominant cause of this higher elasticity of microgels. For our experiment, we prepared a concave microgel of gelatin with two surfaces, with one surface in contact with the lipid membrane and the other without being in contact with the membrane. Next, we measured the elasticities of both the surfaces by using micropipette aspiration. Although the elasticity of the surface not in contact with the lipid membrane was slightly lower than that of the surface in contact with the membrane, the elasticity value was much higher than that for the bulk gel. Further, it was found that the droplet confinement without lipids did not decrease the elasticity of gelatin microgels. These results demonstrate that the dominant factor responsible for the higher elasticity of gelatin microgels is micrometric confinement and not their contact with the lipid membrane..
21. Atsushi Sakai, Yoshihiro Murayama, Kei Fujiwara, Takahiro Fujisawa, Saori Sasaki, Satoru Kidoaki, Miho Yanagisawa, Increasing Elasticity through Changes in the Secondary Structure of Gelatin by Gelation in a Microsized Lipid Space, ACS Central Science, 10.1021/acscentsci.7b00625, 4, 4, 477-483, 2018.04, Even though microgels are used in a wide variety of applications, determining their mechanical properties has been elusive because of the difficulties in analysis. In this study, we investigated the surface elasticity of a spherical microgel of gelatin prepared inside a lipid droplet by using micropipet aspiration. We found that gelation inside a microdroplet covered with lipid membranes increased Young's modulus E toward a plateau value E∗ along with a decrease in gel size. In the case of 5.0 wt % gelatin gelled inside a microsized lipid space, the E∗ for small microgels with R ≤ 50 μm was 10-fold higher (35-39 kPa) than that for the bulk gel (∼3 kPa). Structural analysis using circular dichroism spectroscopy and a fluorescence indicator for ordered beta sheets demonstrated that the smaller microgels contained more beta sheets in the structure than the bulk gel. Our finding indicates that the confinement size of gelling polymers becomes a factor in the variation of elasticity of protein-based microgels via secondary structure changes..
22. H. Ebata, A. Yamamoto, Y. Tsuji, S. Sasaki, K. Moriyama, T. Kuboki, S. Kidoaki, Persistent random deformation model of cells crawling on a gel surface, Sci. Rep., 8, 5153, 2018.03.
23. Kousuke Moriyama, Satoru Kidoaki, Cellular Durotaxis Revisited
Initial-Position-Dependent Determination of the Threshold Stiffness Gradient to Induce Durotaxis, Langmuir, 10.1021/acs.langmuir.8b02529, 2018.01, Directional cell movement from a softer to a stiffer region on a culture substrate with a stiffness gradient, so-called durotaxis, has attracted considerable interest in the field of mechanobiology. Although the strength of a stiffness gradient has been known to influence durotaxis, the precise manipulation of durotactic cells has not been established due to the limited knowledge available on how the threshold stiffness gradient (TG) for durotaxis is determined. In the present study, to clarify the principles for the manipulation of durotaxis, we focused on the absolute stiffness of the soft region and evaluated its effect on the determination of TG required to induce durotaxis. Microelastically patterned gels that differed with respect to both the absolute stiffness of the soft region and the strength of the stiffness gradient were photolithographically prepared using photo-cross-linkable gelatins, and the TG for mesenchymal stem cells (MSCs) was examined systematically for each stiffness value of the soft region. As a result, the TG values for soft regions with stiffnesses of 2.5, 5, and 10 kPa were 0.14, 1.0, and 1.4 kPa/μm, respectively, i.e., TG markedly increased with an increase in the absolute stiffness of the soft region. An analysis of the area and long-axis length for focal adhesions revealed that the adhesivity of MSCs was more stable on a stiffer soft region. These results suggested that the initial location of cells starting durotaxis plays an essential role in determining the TG values and furthermore that the relationship between the position-dependent TG and intrinsic stiffness gradient (IG) of the culture substrate should be carefully reconsidered for inducing durotaxis; IG must be higher than TG (IG ≥ TG). This principle provides a fundamental guide for designing biomaterials to manipulate cellular durotaxis..
24. K. Tamada, E. Usukura, Y. Yanase, A. Ishijima, T. Kuboki, S. Kidoaki, K. Okamoto., LSPR-mediated high axial-resolution fluorescence imaging on a silver nanoparticle sheet, PLOS One, 12, 12, e0189708, 2017.12.
25. S. Masuda, Y. Yanase, E. Usukura, S. Ryuzaki, P. Wang, K. Okamoto, T. Kuboki, S. Kidoaki, and K. Tamada, High-Resolution Imaging of a Cell-Attached Nanointerface Using a Gold-Nanoparticle Two-Dimensional Sheet, Scientific Reports, 7, 3720, 2017.06.
26. Shihomi Masuda, Yuhki Yanase, Eiji Usukura, Sou Ryuzaki, Pangpang Wang, Koichi Okamoto, Thasaneeya Kuboki, Satoru Kidoaki, Kaoru Tamada, High-resolution imaging of a cellattached nanointerface using a gold-nanoparticle two-dimensional sheet, SCIENTIFIC REPORTS, 10.1038/s41598-017-04000-4, 7, 1, 3720, 2017.06, This paper proposes a simple, effective, non-scanning method for the visualization of a cell-attached nanointerface. The method uses localized surface plasmon resonance (LSPR) excited homogeneously on a two-dimensional (2D) self-assembled gold-nanoparticle sheet. The LSPR of the gold-nanoparticle sheet provides high-contrast interfacial images due to the confined light within a region a few tens of nanometers from the particles and the enhancement of fluorescence. Test experiments on rat basophilic leukemia (RBL-2H3) cells with fluorescence-labeled actin filaments revealed high axial and lateral resolution even under a regular epifluorescence microscope, which produced higher quality images than those captured under a total internal reflection fluorescence (TIRF) microscope. This non-scanning-type, high-resolution imaging method will be an effective tool for monitoring interfacial phenomena that exhibit relatively rapid reaction kinetics in various cellular and molecular dynamics..
27. Tomo Kurimura, Yoshiko Takenaka, Satoru Kidoaki, Masatoshi Ichikawa, Fabrication of Gold Microwires by Drying Gold Nanorods Suspensions, Adv. Mater. Interf., DOI: 10.1002/admi.201601125, 1601125, 2017.04.
28. Satoru Kidoaki, Hiroyuki Ebata, Rumi Sawada, Kousuke Moriyama, Thasaneeya Kuboki, Yukie Tsuji, Ken Kono, Kazusa Tanaka, Saori Sasaki, Characterization of the Frustrated Differentiation of Mesenchymal Stem Cells Induced by Normadic Migration Between Stiff and Soft Region of Gel Matrix, BIOPHYSICAL JOURNAL, 10.1016/j.bpj.2016.11.2328, 112, 3, 436A-436A, 2017.02.
29. Naohiko Shimada, Minako Saito, Sayaka Shukuri, Sotaro Kuroyanagi, Thasaneeya Kuboki, Satoru Kidoaki, Takeharu Nagai, Atsushi Maruyama, Reversible monolayer/spheroid cell culture switching by UCST-type thermoresponsive ureido polymers, ACS Applied Mater. Interf., DOI: 10.1021/acsami.6b07614, 8, 31524-31529, 2016.11.
30. T. Kuboki, S. Kidoaki, Fabrication of elasticity-tunable gelatinous gel for mesenchymal stem cell culture, Methods Mol. Biol., DOI 10.1007/978-1-4939-3584-0_25, 1416, 425-441, 2016.04.
31. Fahsai Kantawong, Thasaneeya Kuboki, Satoru Kidoaki, Redox gene expression of adipose-derived stem cells in response to soft hydrogel, Turkish Journal of Biology, 39, 682-691, 2015.06.
32. Ayaka Ueki, Satoru Kidoaki, Manipulation of cell mechanotaxis by designing curvature of the elasticity boundary on hydrogel matrix, Biomaterials, 41, 45-52, 2015, 2014.12.
33. Naohiko Shimada, Satoru Kidoaki, Atsushi Maruyama, Smart hydrogels exhibiting UCST-type volume changes under physiologically relevant conditions , RSC Advances, 4, 52346, 2014, 2014.10.
34. Thasaneeya Kuboki, Wei Chen, Satoru Kidoaki, Time-dependent migratory behaviors in the long-term studies of fibroblast durotaxis on a hydrogel substrate fabricated with a soft band, Langmuir, 30, 6187-6196., 2014.06.
35. Hiroyuki Sakashita, Satoru Kidoaki, Rectified cell migration on saw-like micro-elastically patterned hydrogels with asymmetric gradient ratchet teeth, PLOS One, 8, 10, e78067, 2013.10.
36. Takahito Kawano, Satoru Kidoaki, Corrigendum to "Elasticity boundary conditions required for cell mechanotaxis on microelastically-patterned gels" [Biomaterials 32(2011) 2725-33], Biomaterials, 10.1016/j.biomaterials.2013.06.011, 34, 30, 7563-7564, 2013.10.
37. Satoru Kidoaki, Hiroyuki Sakashita, Rectified Cell Migration on Saw-Like Micro-Elastically Patterned Hydrogels with Asymmetric Gradient Ratchet Teeth, PLOS ONE, 10.1371/journal.pone.0078067, 8, 10, e78067, 2013.10, To control cell motility is one of the essential technologies for biomedical engineering. To establish a methodology of the surface design of elastic substrate to control the long-range cell movements, here we report a sophisticated cell culture hydrogel with a micro-elastically patterned surface that allows long-range durotaxis. This hydrogel has a sawlike pattern with asymmetric gradient ratchet teeth, and rectifies random cell movements. Durotaxis only occurs at boundaries in which the gradient strength of elasticity is above a threshold level. Consequently, in gels with unit teeth patterns, durotaxis should only occur at the sides of the teeth in which the gradient strength of elasticity is above this threshold level. Therefore, such gels are expected to support the long-range biased movement of cells via a mechanism similar to the Feynman-Smoluchowski ratchet, i.e., rectified cell migration. The present study verifies this working hypothesis by using photolithographic microelasticity patterning of photocurable gelatin gels. Gels in which each teeth unit was 100-120 mu m wide with a ratio of ascending: descending elasticity gradient of 1: 2 and a peak elasticity of ca. 100 kPa supported the efficient rectified migration of 3T3 fibroblast cells. In addition, long-range cell migration was most efficient when soft lanes were introduced perpendicular to the saw-like patterns. This study demonstrates that asymmetric elasticity gradient patterning of cell culture gels is a versatile means of manipulating cell motility..
38. Tatsuya Okuda, Yoshiro Tahara, Noriho Kamiya, Masahiro Goto, Satoru Kidoaki, S/O-nanodispersion electrospun fiber mesh effective for sustained release of healthy plasmid DNA with the structural and functional integrity, JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION, 10.1080/09205063.2012.755600, 24, 10, 1277-1290, 2013.07, Localized and sustained delivery of the therapeutic genes using a solid carrier matrix is a potential approach to develop highly curative treatments. Electrospun nanofiber mesh of biodegradable polymer has been applied extensively as a carrier for localized and sustained delivery of drugs, proteins, and DNA, but it remains difficult to release sufficient amounts of DNA while maintaining structural and functional integrity. To realize the stable sustained release of the healthy plasmid DNA (pDNA) from electrospun fiber mesh, a novel method was examined for loading pDNA into the fibers based on solid-in-oil (S/O) nanodispersion of pDNA in organic solvent for electrospinning polymer solution: S/O nanodispersion electrospinning. A prepared pDNA-loaded fiber mesh made of biodegradable polymer showed sustained release of pDNA without burst release. From luciferase activity-based in vitro transcriptiontranslation assay, pDNA released from meshes of the S/O nanodispersion retained about 60% luciferase activity of control pDNA, whereas pDNA released from the meshes of simple mixing showed only about 5% activity, indicating that S/O nanodispersion electrospinning is effective for loading pDNA into electrospun fiber meshes while maintaining their healthy functions. Effectiveness of S/O nanodispersion electrospinning was verified for fabricating a sustained release carrier matrix for high molecular weight bioactives, including therapeutic genes..
39. Hiroshi Yoshikawa, Takahito Kawano, Takehisa Matsuda, Satoru Kidoaki, Motomu Tanaka, Morphology and adhesion strength of myoblast cells on photocurable gelatin under native and non-native micromechanical environments, J. Phys. Chem. Part B, 117, 4081-4088, 2013.05.
40. Hiroshi Y. Yoshikawa, Takahito Kawano, Takehisa Matsuda, Satoru Kidoaki, Motomu Tanaka, Morphology and Adhesion Strength of Myoblast Cells on Photocurable Gelatin under Native and Non-native Micromechanical Environments, JOURNAL OF PHYSICAL CHEMISTRY B, 10.1021/jp4008224, 117, 15, 4081-4088, 2013.04, We have quantitatively determined how the morphology and adhesion strength of myoblast cells can be regulated by photocurable gelatin gels, whose mechanical properties can be fine-tuned by a factor of 10(3) (0.1 kPa
41. Yasuhiro Matsuda, Kazumasa Takatsuji, Yasunori Shimokawa, Moriya Kikuchi, Satoru Kidoaki, Atsushi Takahara, Shigeru Tasaka, Characterization of Complexes Formed by Mixing Aqueous Solutions of Poly(2-Ethyl-2-Oxazoline) and Poly(Methacrylic Acid) with a Wide Range of Concentrations, Polymer, 54, 1896-1904, 2013.03.
42. T. Okuda, Y. Tahara, N. Kamiya, M. Goto, and S. Kidoaki, S/O-nanodispersion electrospun fiber mesh effective for sustained release of healthy plasmid DNA with the structural and functional Integrity, Journal of Biomaterials Science: Polymer Edition, 24, 1277-1290, 2013.01.
43. S. Shibano, K. Sasaki, S. Kidoaki, T. Iwaki, Detection of Prion Protein Oligomers by Single Molecule Fluorescence Imaging, Neuropathology, 33,1-6, 2012.03.
44. M. Horning, S. Kidoaki, T. Kawano, K. Yoshikawa, Rigidity-matching between cells and the extracellular matrix leads to the stabilization of cardiac conduction, Biophys. J., 102, 379-387, 2012.02.
45. Marcel Hoerning, Satoru Kidoaki, Takahito Kawano, Kenichi Yoshikawa, Rigidity Matching between Cells and the Extracellular Matrix Leads to the Stabilization of Cardiac Conduction, BIOPHYSICAL JOURNAL, 10.1016/j.bpj.2011.12.018, 102, 3, 379-387, 2012.02, Biomechanical dynamic interactions between cells and the extracellular environment dynamically regulate physiological tissue behavior in living organisms, such as that seen in tissue maintenance and remodeling. In this study, the substrate-induced modulation of synchronized beating in cultured cardiomyocyte tissue was systematically characterized on elasticity-tunable substrates to elucidate the effect of biomechanical coupling. We found that myocardial conduction is significantly promoted when the rigidity of the cell culture environment matches that of the cardiac cells (4 kiloPascals). The stability of spontaneous target wave activity and calcium transient alternans in high frequency-paced tissue were both enhanced when the cell substrate and cell tissue showed the same rigidity. By adapting a simple theoretical model, we reproduced the experimental trend on the rigidity matching for the synchronized excitation. We conclude that rigidity matching in cell-to-substrate interactions critically improves cardiomyocyte-tissue synchronization, suggesting that mechanical coupling plays an essential role in the dynamic activity of the beating heart..
46. T. Okuda and S. Kidoaki, Multidrug delivery systems with single formulation ~current status and future perspective~, Journal of Biomaterials and Nanobiotechnology, 3, 50-60, 2012.01.
47. Satoru Kidoaki, Shuhei Jinnouchi, Frustrated Differentiation of Mesenchymal Stem Cell Cultured on Microelastically-Patterned Photocurable Gelatinous Gels, BIOPHYSICAL JOURNAL, 10.1016/j.bpj.2011.11.3885, 102, 3, 716A-716A, 2012.01.
48. Takahito Kawano, Satoru Kidoaki, Elasticity boundary conditions required for cell mechanotaxis on microelastically-patterned gels, BIOMATERIALS, 10.1016/j.biomaterials.2011.01.009, 32, 11, 2725-2733, 2011.04, Directional cell migration induced by a mechanical gradient on a substrate surface toward a harder region, so-called mechanotaxis or durotaxis, has recently drawn attention not only in the field of mechanobiology but also for possible cell manipulation in biomedical engineering. Before we can use mechanotaxis to control cell migration on a biomaterial surface, quantitative design criteria for a microelasticity gradient should be established. To clarify the conditions required to induce mechanotaxis, the effects of a microelasticity boundary on cell culture hydrogels have been systematically assessed with regard to fibroblast migration based on a custom-built reduction projection-type photolithographic microelasticity patterning system with elasticity-tunable photocurable styrenated gelatins, which is a thoroughly-improved system of our previous simple photomasking method [41]. As a result, the conditions required to induce mechanotaxis were found to include a certain threshold jump in elasticity (30-40 kPa) and a sufficiently narrow width of the elasticity boundary (50 pm) comparable to a single cell's adhered area, i.e., a sufficiently high gradient strength (30-40 kPa/50 pm in our gelatinous gel system). A significant asymmetric distribution of the number and size of focal adhesions across the elasticity boundary was confirmed to be one of the driving factors of mechanotaxis by indirect immunofluorescence microscopy, and mechanistic considerations in the design criteria are discussed. (C) 2011 Elsevier Ltd. All rights reserved..
49. Naotaka Sonda, Masanori Hirano, Naohiko Shimada, Arihiro Kano, Satoru Kidoaki, Atsushi Maruyama, Cationic Comb-type Copolymers Do Not Cause Collapse but Shrinkage of DNA Molecules, CHEMISTRY LETTERS, 10.1246/cl.2011.250, 40, 3, 250-251, 2011.03, A flow-stretching assay was employed to elucidate polycation/DNA interactions at the single-molecule level. Bacteriophage lambda-DNA (48.5 kbp) was attached at one end to a PEG-modified glass surface and stretched by buffer flow. The stretched DNA had an approximate length of 12 mu m. Upon injection of polylysine homopolymer, the DNA folded into a globule structure within a few seconds. Injection of a polylysine graft copolymer having hydrophilic dextran side chains also induced collapse of the stretched DNA. In comparison to these polymer, a copolymer with higher graft content did not cause DNA collapse but rather caused 25% shrinkage of the extended DNA. These results were compared with those observed with unstretched DNA..
50. N. Sonda, M. Hirano, N. Shimada, A. Kano, S. Kidoaki, A.Maruyama, Cationic Comb-type Copolymers Do Not Cause Collapse but Shrinkage of DNA Molecules, Chem. Lett., 40: 250-251 (2011)., 2011.02.
51. T. Kawano and S. Kidoaki, Elasticity boundary conditions required for cell mechanotaxis on microelastically-patterned gels, Biomaterials, 32: 2725-2733 (2011)., 2011.01, 細胞は弾性基材表面の硬い領域を指向して運動する性質を示す(メカノタクシス)ことが知られていたが、その駆動のための表面弾性勾配の定量的条件は確立されておらず、メカノタクシスを系統的に誘導し制御することは不可能であった。本論文ではこの問題に対して、独自の弾性率可変ヒドロゲルのマイクロ弾性パターニング技術を確立することにより、細胞のメカノタクシスの誘導条件を初めて明確にした。その技術は細胞運動を操作する培養基材設計の一般的な基礎となるものである。.
52. T. Nakagaki, A. Harano, Y. Fuchigami, E. Tanaka, S. Kidoaki, T. Okuda, T. Iwanaga, K. Goto, T. Shinmyuzu, Formation of Nanoporous Fibers by the Self-Assembly of Pyromellitic Diimide-Based Macrocycle, Ang. Chem. Int. Ed., 45: 1-5 (2010)., 2010.11.
53. T. Okuda and S. Kidoaki, Development of time-programmed, dual-release system using multilayered fiber mesh sheet by sequential electrospinning, Journal of Robotics and Mechatronics, 22(5): 4457-4465 (2010)., 2010.05.
54. Tatsuya Okuda, Kengo Tominaga, Satoru Kidoaki, Time-programmed dual release formulation by multilayered drug-loaded nanofiber meshes, JOURNAL OF CONTROLLED RELEASE, 10.1016/j.jconrel.2009.12.029, 143, 2, 258-264, 2010.04, To develop a drug carrier that enables time-programmed dual release in a single formulation, multilayered drug-loaded biodegradable nanofiber meshes were designed using sequential electrospinning with the following construction: (i) first drug-loaded mesh (top), (ii) barrier mesh, (iii) second drug-loaded mesh, and (iv) basement mesh (bottom). The drug release speed and duration were controlled by designing morphological features of the electrospun meshes such as the fiber diameter and mesh thickness. Control of the timed release of the second drug-the retardation period-was accomplished by appropriate design of the barrier mesh thickness. An in vitro release experiment demonstrated that the tetra-layered construction described above with appropriate morphological features of each component mesh can provide timed dual release of the respective drugs. The time-programmed dual release system using the multilayered electrospun nanofiber meshes was demonstrated as a useful formulation for advanced multidrug combination therapy requiring regiospecific administration of different drugs at different times. The potential use of the present multilayered formulation is discussed for application to biochemical modulation as one administrative strategy for use in sequential chemotherapy employing multiple anti-tumor drugs. (C) 2010 Elsevier B.V. All rights reserved..
55. N. Chen, A. Zinchenko, S. Kidoaki, M. Murata, K. Yoshikawa, Thermo-Switching of the Conformation of Genomic DNA in Solutions of Poly-(N-isopropylacrylamide), Langmuir, 26, 2995-2998 (2010)., 2010.03.
56. Ning Chen, Anatoly A. Zinchenko, Satoru Kidoaki, Shizuaki Murata, Kenichi Yoshikawa, Thermo-Switching of the Conformation of Genomic DNA in Solutions of Poly (N-isopropylacrylamide), LANGMUIR, 10.1021/la904375k, 26, 5, 2995-2998, 2010.03, We used poly(N-isopropylacrylamide) (PNIPAM) to control the conformation of genomic DNA by changing the temperature of a reaction solution and studied the DNA transition at the level of single DNA molecules. With this method, the conformation of long genomic DNA can be readily and reversibly switched between it very compact condensate and an unfolded macromolecule..
57. T. Okuda, K. Tominaga, S. Kidoaki, Time-programmed dual release formulation by multilayered drug-loaded nanofiber meshes, Journal of Controlled Release, 143, 2, 258-564, 143(2), 258-564 (2010)., 2010.02.
58. Satoru Kidoaki, Takahito Kawano, Hiroyuki Sakashita, Development of Micropatterned Elastic Gelatinous gels to Control Cell Mechanotaxis, BIOPHYSICAL JOURNAL, 10.1016/j.bpj.2009.12.3998, 98, 3, 729A-729A, 2010.01.
59. Fuyu Ito, Kengo Usui, Daigo Kawahara, Atsushi Suenaga, Tei Maki, Satoru Kidoaki, Harukazu Suzuki, Makoto Taiji, Masayoshi Itoh, Yoshihide Hayashizaki, Takehisa Matsuda, Reversible hydrogel formation driven by protein-peptide-specific interaction and chondrocyte entrapment, BIOMATERIALS, 10.1016/j.biomaterials.2009.09.026, 31, 1, 58-66, 2010.01, We developed a hydrogel self-assembling method driven by the interaction between recombinant tax-interactive protein-1 (TIP1) with the PDZ domain in a molecule, which is fused to each end of the triangular trimeric CutA protein (CutA-TIP1), and a PDZ domain-recognizable peptide which is covalently bound to each terminus of four-armed poly(ethylene glycol) (PDZ-peptide-PEG). Genetic manipulation based on molecular-dynamic simulation generated a cell-adhesive RGD tripeptidyl sequence in the CutA loop region [CutA(RGD)-TIP1]. Spontaneous viscoelastic hydrogel formation occurred when either CutA-TIP1- or CutA(RGD)-TIP1-containing buffer solution and PDZ-peptide-PEG-containing buffer solutions were stoichiometrically mixed. Dynamic viscoelasticity measurement revealed shear stress-dependent reversible-phase transformation: a spontaneous viscoelastic hydrogel was formed at low shear stress, but it was transformed into a sol at high shear stress. Upon the cessation of shear, hydrogel was restored. When chondrocytes were pre-mixed with one of these two components containing buffer solutions, the stoichiometric mixed solution was also spontaneously gelled. Individual rounded cells and multicellular aggregates were entrapped within both hydrogels without substantial cellular impairment regardless of the presence or absence of RGD motif in the CutA-TIP1 molecule. The potential use of such a shear-sensitive hydrogel for injectable cell delivery into diseased or lost cartilage tissue is discussed. (C) 2009 Elsevier Ltd. All rights reserved..
60. F. Ito, K. Usui, D. Kawahara, A. Suenaga, T. Maki, S. Kidoaki, H. Suzuki, M. Taiji, M. Itoh, Y. Hayashizaki, T. Matsuda, Protein-peptide specific interaction-driven hydrogel formation, hydrodynamic shear stress-dependent gel-to-sol reversibility and its potential application to injectable cartilage tissue, Biomaterials, 31, 58-66 (2009)., 2009.09.
61. K. Usui, T. Maki, F. Ito, A. Suenaga, S. Kidoaki, M. Itoh, M. Taiji, T. Matsuda, Y. Hayashizaki, H. Suzuki, Nanoscale elongating control of the self-assembled protein filament with the cysteine-introduced building blocks, Protein Science, 18, 960-969, 18, 960-969 (2009)., 2009.02.
62. S. Kidoaki, T. Matsuda, Vectorial control of cell movement by the design of microelasticity distribution of biomaterial surface, IEEE International Symposium on Micro-NanoMechatronics and Human Science, 469-474 (2008), 2008.11.
63. M. Hirano, N. Shimada, A. Kano, S. Kidoaki, A. Maruyama, Analysis of cationic comb-type copolymers/DNA interaction by the single molecular observation and intermolecular force measurement, Nucleic Acids Symposium Series, 19(1): 61-74, (2008)., 2008.07.
64. S. Kidoaki and T. Matsuda, Microelastic gradient gelatinous gels to induce cellular mechanotaxis, Journal of Biotechnology, 133, 225-230 (2008)., 2008.01.
65. Satoru Kidoaki, Takehisa Matsuda, Microelastic gradient gelatinous gels to induce cellular mechanotaxis, JOURNAL OF BIOTECHNOLOGY, 10.1016/j.jbiotec.2007.08.015, 133, 2, 225-230, 2008.01, The understanding and realization of directional cell movement towards a harder region of a cell culture substrate surface, so-called mechanotaxis, might provide a solid basis for a functional artificial extracellular matrix, enabling manipulation and elucidation of cell motility. The photolithographic surface microelasticity patterning method was developed for fabricating a cell-adhesive hydrogel with a microelasticity gradient (MEG) surface using photocurable styrenated gelatin to investigate the condition of surface elasticity to induce mechanotaxis as a basis for such substrate-elasticity-dependent control of cell motility. Patterned MEG gels consisting of different absolute surface elasticities and elasticity jumps were prepared. Surface elasticity and its two-dimensional distribution were characterized by microindentation tests using atomic force microscopy (AFM). From analyses of trajectories of 3T3 cell movement on each prepared MEG gel, two critical criteria of the elasticity jump and the absolute elasticity to induce mechanotaxis were identified: (1) a high elasticity ratio between the hard region and the soft one, and (2) elasticity of the softer region to provide medium motility. Design of these conditions was found to be necessary for fabricating an artificial extracellular matrix to control or manipulate cell motility. (c) 2007 Elsevier B.V. All rights reserved..
66. Energy Landscape Analysis of the Biomolecular Interactions.
67. S. Kidoaki and T. Matsuda, Shape-engineered fibroblasts: cell elasticity and actin cytoskeletal features characterized by fluorescence and atomic force microscopy, Journal of Biomedical Materials Research: Part A, 81, 728-735, 2007.06.
68. S. Kidoaki and T. Matsuda, Shape-engineered vascular endothelial cells: nitric oxide production, cell elasticity, and actin cytoskeletal features, Journal of Biomedical Materials Research: Part A, 81, 803-810, 81, 803-810 (2007)., 2007.06.
69. T. Maki, S. Kidoaki, K. Usui, H. Suzuki, M. Ito, F. Ito, Y. Hayashizaki, T. Matsuda, Dynamic force spectroscopy of the specific interaction between PDZ-domain and its recognition peptides, Langmuir, 23, 2668-2673 (2007)., 2007.01.
70. S. Kidoaki, T. Matsuda, K. Yoshikawa, Relationship between apical membrane elasticity and stress fiber organization in fibroblasts analyzed by fluorescence and atomic force microscopy, Biomechan Model Mechanobiol, 5, 263-272 (2006)., 2006.11.
71. S. Kidoaki and T. Matsuda, Characterization of the cellular biomechanical responses caused on microprocessed substrates: effect of micropatterned cell adhesiveness and microelasticity gradient, , IEEE International Symposium on Micro-NanoMechatronics and Human Science, 5, 63-69, 5, 63-69 (2006)., 2006.11.
72. Satoru Kidoaki, Il Keun Kwon, Takehisa Matsuda, Structural features and mechanical properties of in situ-bonded meshes of segmented polyurethane electrospun from mixed solvents, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.30336, 76, 1, 219-229, 2006.01, The relationships between the structural features and mechanical properties of electrospun segmented polyurethane (SPU) meshes and electrospinning parameters such as formulation (e.g., polymer concentration and solvent mixing ratio) and operation parameters (e.g., applied voltage, air gap, and flow rate) were studied with the use of a mixed-solvent system of tetrahydrofuran (THF) and N,N-dimethylacrylamide (DMF). After the relationships between the structure of electrospun SPU and the operation parameters under a fixed SPU concentration of single THF solution were established, SPU was electrospun from the mixed solvent of THF and DMF with different mixing ratios [DMF content: 5, 10, and 30% (v/v)]. Scanning electron microscopy showed that an increase in DMF ratio significantly enhances the degree of bonding between SPU fibers at contact sites and decreases the diameter of fibers formed. The porosimetric characterization showed the following: (1) The porosity of the electrospun SPU meshes decreased with an increase of DMF ratio. (2) The pore size distribution exhibited three representative peaks of different void sizes (i.e., approximately 5, 20, and 70 μm). (3) The proportion of the 20-μm void markedly decreased with an increase in DMF ratio. A tensile test on the meshes showed that an increase in DMF ratio induces an increase in elasticity of the mesh. Such a regulation of the structural features and mechanical properties of electrospun SPU meshes using a mixed-solvent system with low- and high-boiling-point solvents may be useful in the engineering of SPU-fiber based matrices or scaffolds. © 2005 Wiley Periodicals, Inc..
73. T. Matsuda and S. Kidoaki, Mechanobiology of cell and tissue engineering and multi-scaled process engineering, IEEE International Symposium on Micro-NanoMechatronics and Human Science, 5, 203-205, 5, 203-205 (2005)., 2005.11.
74. A Idiris, S Kidoaki, K Usui, T Maki, H Suzuki, M Ito, M Aoki, Y Hayashizaki, T Matsuda, Force measurement for antigen-antibody interaction by atomic force microscopy using a photograft-polymer spacer, BIOMACROMOLECULES, 10.1021/bm0502617, 6, 5, 2776-2784, 2005.09, To determine the intermolecular force on protein-protein interaction (PPI) by atomic force microscopy (AFM), a photograft-polymer spacer for protein molecules on both surfaces of the substrate and AFM probe tip was developed, and its effectiveness was assessed in a PPI model of a pair of human serum albumin (HSA) and its monoclonal antibody (anti-HSA). A carboxylated photoiniferter, N-(dithiocarboxy)sarcosine, was derivatized on both surfaces of the glass substrate and AFM probe tip, and subsequently water-soluble nonionic vinyl monomers, NN-dimethylacrylamide (DMAAm), were graft-polymerized on them upon ultraviolet light irradiation. DMAAm-photograft-polymerized spacers with carboxyl groups at the growing chain end but with different chain lengths on both surfaces were prepared. The proteins were covalently bound to the carboxyl terminus of the photograft-polymer chain using a water-soluble condensation agent. The effects of the graft-spacer length on the profile of the force-distance curves and on the unbinding characteristics (unbinding force and unbinding distance) were examined in comparison with those in the case of the commercially available poly(ethylene glycol) (PEG) spacer. The frequency of the nonspecific adhesion force profile was markedly decreased with the use of the photograft spacers. Among the force curves detected, a high frequency of single-peak curves indicating the unbinding process of a single pair of proteins and a very low frequency of multiple-peak profiles were observed for the photograft spacers, regardless of the graft chain length, whereas a high frequency of no-force peaks was noted. These observations were in marked contrast with those for the PEG spacer. The force peak values determined ranged from 88 to 94 pN, irrespective of the type of spacer, while the standard deviation of force distribution observed for the photograft spacer was lower than that for the PEG spacer, indicating that the photograft spacers provide a higher accuracy of force determination..
75. IK Kwon, S Kidoaki, T Matsuda, Electrospun nano- to microfiber fabrics made of biodegradable copolyesters: structural characteristics, mechanical properties and cell adhesion potential, BIOMATERIALS, 10.1016/j.biomaterials.2004.10.007, 26, 18, 3929-3939, 2005.06, Nano- to micro-structured biodegradable poly(L-lactide-co-epsilon-caprolactone) (PLCL) fabrics were prepared by electrospinning. Electrospun microfiber fabrics with different compositions of PLCL (mol% in feed; 70/30, 50150, and 30/70), poly(L-lactide) (PLL) and poly(c-caprolactone) (PCL) were obtained using methylene chloride (MC) as a solvent. The PLL microfiber exhibited a nanoscale-pore structure with a pore diameter of approximately 200-800 mn at the surface and subsurface regions, whereas such a surface structure was hardly observed in other polymers containing CL. The microfiber fabric made of PLCL 50/50 was elastomeric. Nanoscale-fiber fabrics with PLCL 50/50 (approx. 0.3 or 1.2 mum in diameter) were electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent. Mercury porosimetry showed that the decrease in the fiber diameter of the fabric decreased porosity, but increased fiber density and mechanical strength. Human umbilical vein endothelial cells (HUVECs) were adhered well and proliferated on the small-diameter-fiber fabrics (0.3 and 1.2 mum in diameter), both of which are dense fabrics, whereas markedly reduced cell adhesion, restricted cell spreading and no signs of proliferation were observed on the large-diameter-fiber fabric (7.0 mum in diameter), The potential biomedical application of electrospun PLCL 50/50 was discussed. (C) 2004 Elsevier Ltd. All rights reserved..
76. S Ohya, S Kidoaki, T Matsuda, Poly(N-isopropylacrylamide) (PNIPAM)-grafted gelatin hydrogel surfaces: interrelationship between microscopic structure and mechanical property of surface regions and cell adhesiveness, BIOMATERIALS, 10.1016/j.biomaterials.2004.08.006, 26, 16, 3105-3111, 2005.06, Poly(jV-isopropylacrylamide)-grafted gelatin (PNIPAM-gelatin) serves as a temperature-induced scaffold at physiological temperature. This study was aimed at determining the effect of the graft architecture of thermoresponsive PNIPAM-gelatin on the surface topography and elastic modulus of the hydrogels prepared with different architectured PNIPAM-gelatins: the surface topography and elastic modulus were determined by atomic force microscopy (AFM). PNIPAM-gelatin surfaces showed an irregularly concavo-convex structure with a vertical interval of approximately I pm regardless of the weight ratio of PNIPAM to gelatin (P/G: 5.8, 12, and 18). The elastic moduli of hydrogels varied at measured sites. The mean elastic moduli of PNIPAM-gelatin with the lowest P/G were low, but increased with increasing P/G. Human umbilical vein endothelial cells adhered and spread on PNIPAM-gelatin hydrogels with the highest P/G, whereas reduced adhesion and nonspreading, round-shaped cells resided on the hydrogels with lower P/Gs. Interrelationship between elastic modulus and cell adhesion and spreading potentials were discussed from physicochemical and cellular biomechanical viewpoints. (C) 2004 Elsevier Ltd. All rights reserved..
77. Takehisa Matsuda, Maki Ihara, Hiroyuki Inoguchi, Il Keun Kwon, Keiichi Takamizawa, Satoru Kidoaki, Mechano-active scaffold design of small-diameter artificial graft made of electrospun segmented polyurethane fabrics, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.30260, 73, 1, 125-131, 2005.04, To fabricate a "mechano-active" tubular scaffold of nonwoven mesh-type small-diameter artificial graft made of the synthetic durable elastomer, segmented polyurethane, the fabrication technique of electrospinning on a mandrel under a high rotation speed and transverse movement was used. Emphasis was placed on how the rotation speed of the mandrel and the fusion or welding states of fibers at contact points affect the compliance (ease of intraluminal pressure-dependent circumferential inflation) and Young's modulus determined by uniaxial stretching in the longitudinal and circumferential directions. The results showed that a high rotation speed is attributed to exhibit isotropic mechanical properties in the entire range of applied strain but reduces the compliance, and a high fusion state, which is produced using a mixed solvent with a high content of high-boiling-point solvent, reduces the compliance but is expected to exhibit high durability in a continuously loaded pulsatile stress field in an arterial circulatory system. © 2005 Wiley Periodicals, Inc..
78. S. Kidoaki, I.K. Kwon, T. Matsuda, Mesoscopic spatial designs of nano- and micron-fiber meshes for tissue-engineering matrix and scaffold based on newly devised multilayering and mixing electrospinning techniques, Biomaterials, 10.1016/j.biomaterials.2004.01.063, 26, 1, 37-46, 26(1), 37-46 (2005)., 2005.01.
79. S. Ohya, S. Kidoaki, T. Matsuda, Poly(N-isopropylacrylamide) (PNIPAAM)-grafted hydrogel surfaces: Interrelationship between microscopic structures and mechanical property of surface regions and cell adhesiveness, Biomaterials, 10.1016/j.biomaterials.2004.08.006, 26, 16, 3105-3111, 26, 3105-3111 (2005)., 2005.01.
80. I.K. Kwon, S. Kidoaki, T. Matsuda, Electrospun nano- to microfiber fabrics made of biodegradable copolyesters: structural characteristics, mechanical properties and cell adhesion potential, Biomaterials, 10.1016/j.biomaterials.2004.10.007, 26, 18, 3929-3939, 26(18), 3929-3939 (2005)., 2005.01.
81. T. Matsuda, M. Ihara, H. Inoguchi, I.K. Kwon, K. Takamizawa, S. Kidoaki, Mechano-active scaffold design of small-diameter artificial graft made of electrospun segmented polyurethane mesh fabrics, J. Biomed. Mater. Res. A, 10.1002/jbm.a.30260, 73A, 1, 125-131, 73, 125-131 (2005)., 2005.01.
82. A. Takahara, M. Hadano, T. Yamaguchi, H. Otsuka, S. Kidoaki, T. Matsuda, Characterization of novel bio-degradable segmented polyurethanes prepared from amino-acid based diisocyanate, Macromolecular Symp, 10.1002/masy.200550618, 224, 207-217, 224, 207-217 (2005)., 2005.01.
83. S. Kidoaki, I.K. Kwon, T. Matsuda, Structural feature and mechanical property of in situ-bonded meshes of segmented polyurethane electrospun from mixed solvents, J. Biomed. Mater. Res. B, 10.1002/jbm.b.30336, 76B, 1, 219-229, 76, 219-229 (2005)., 2005.01.
84. A. Idiris, S. Kidoaki, K. Usui, T. Maki, H. Suzuki, M. Ito, M. Aoki, Y. Hayashizaki, T. Matsuda, Force measurement on antigen-antibody interaction by atomic force microscopy using photograft-polymer spacer, Biomacromolecules, 10.1021/bm0502617, 6, 5, 2776-2784, 6, 2776-2784 (2005)., 2005.01.
85. K. Usui, S. Katayama, M. Kanamori, C. Kai, M. Okada, J. Kawai, T. Arakawa, P. Carninci, K. Takio, M. Miyano, S. Kidoaki, T. Matsuda, Y. Hayashizaki, H. Suzuki., Protein-protein interactions of the hyperthermophilic archaeon Pyrococcus horikoshii OT3, Genome Biology, 10.1186/gb-2005-6-12-r98, 6, 12, 6, R98 (2005)., 2005.01.
86. S Kidoaki, IK Kwon, T Matsuda, Mesoscopic spatial designs of nano- and microfiber meshes for tissue-engineering matrix and scaffold based on newly devised multilayering and mixing electrospinning techniques, BIOMATERIALS, 10.1016/j.biomaterials.2004.01.063, 26, 1, 37-46, 2005.01, To design a mesoscopically ordered structure of the matrices and scaffolds composed of nano- and microscale fiber meshes for artificial and tissue-engineering devices, two new electrospinning techniques are proposed: multilayering electrospinning and mixing electrospinning. First, the following four kinds of component polymers were individually electrospun to determine the conditions for producing stable nano- and microfibers by optimizing the formulation parameters (solvent and polymer concentration) and operation parameters (voltage, air gap, and flow rate) for each polymer: (a) type I collagen, (b) styrenated gelatin (ST-gelatin), (c) segmented polyurethane (SPU), and (d) poly(ethylene oxide). A trilayered electrospun mesh, in which individual fiber meshes (type I collagen, ST-gelatin, and SPU) were deposited layer by layer, was formed by sequential electrospinning; this was clearly visualized by confocal laser scanning microscopy. The mixed electrospun-fiber mesh composed of SPU and PEO was prepared by simultaneous electrospinning on a stainless-steel mandrel with high-speed rotation and traverse movement. A bilayered tubular construct composed of a thick SPU microfiber mesh as an outer layer and a thin type I collagen nanofiber mesh as an inner layer was fabricated as a prototype scaffold of artificial grafts, and visualized by scanning electron microscopy. (C) 2004 Elsevier Ltd. All rights reserved..
87. T Matsuda, IK Kwon, S Kidoaki, Photocurable biodegradable liquid copolymers: Synthesis of acrylate-end-capped trimethylene carbonate-based prepolymers, photocuring, and hydrolysis, BIOMACROMOLECULES, 10.1021/bm034231k, 5, 2, 295-305, 2004.03, Various photocurable liquid biodegradable trimethylene carbonate (TMC)-based (co)oligomers were prepared by ring-opening (co)polymerization of TMC with or without L-lactide (LL) using low molecular weight poly(ethylene glycol) (PEG) (mol wt 200, 600, or 1000) or trimethylolpropane (TMP) as an initiator. Resultant (co)oligomers were pastes, viscous liquids, or liquids at room temperature, depending on the monomer composition and monomer/initiator ratio. Liquid (co)oligomers were subsequently end-capped with acrylate groups. Upon visible-light irradiation in the presence of camphorquinone as a radical generator, rapid liquid-to-solid transformation occurred to produce photocured solid. The photocuring yield increased with photoirradiation time, photointensity, and camphorquinone concentration. The photocured polymers derived from low molecular weight PEG (PEG200) and TMP exhibited much reduced hydrolysis potential compared with PEG1000-derived polymers in terms of weight loss, water uptake, and swelling depth. Force-distance curve measurements by nanoindentation using atomic force microscopy clearly showed that Young's moduli of the photocured polymer films decreased with increasing hydrolysis time. Their potential biomedical applications are discussed..
88. T Iwataki, S Kidoaki, T Sakaue, K Yoshikawa, SS Abramchuk, Competition between compaction of single chains and bundling of multiple chains in giant DNA molecules, JOURNAL OF CHEMICAL PHYSICS, 10.1063/1.1642610, 120, 8, 4004-4011, 2004.02, It has been established that in a dilute solution individual giant DNA molecules undergo a large discrete transition between an elongated coil state and a folded compact state. On the other hand, in concentrated solutions, DNA molecules assemble into various characteristic states, including multichain aggregate, liquid crystalline, ionic crystal, etc. In this study, we compared single-chain and multiple-chain events by observing individual chains using fluorescence microscopy. We used spermidine, SPD(3+), as a condensing agent for giant DNA. When the concentration of DNA is below 1 muM in base-pair units, individual DNA molecules exhibit a transition from an elongated state to a compact state. When the concentration of DNA is increased to 10 muM, a thick fiberlike assembly of multiple chains appears. AFM measurements of this thick fiber revealed that more than tens of DNA molecules form a bundle structure with parallel ordering of the chains. The transition between single-chain compaction and bundle formation with multiple-chain assemblies was reproduced by a theoretical calculation. (C) 2004 American Institute of Physics..
89. Substrate-dependent cellular behavior of Swiss 3T3 fibroblasts and activation of Rho family during adhesion and spreading processes..
90. S. Kato, S. Kidoaki, T. Matsuda, Substrate-dependent Cellular Behaviors of Swiss 3T3 Fibroblasts and Activation of Rho Family during Adhesional and Spreading Processes, J. Biomed. Mater. Res, 10.1002/jbm.a.20012, 68A, 2, 314-324, 68, 314-324 (2004)., 2004.01.
91. T. Iwataki, S. Kidoaki, T. Sakaue, K. Yoshikawa, and S. S. Abramuchuk, Competition Between Compaction of Single Chains and Bundling of Multiple Chains in Giant DNA Molecules, J. Chem. Phys, 120、4004−4011 (2004)., 2004.01.
92. T. Matsuda, I.K. Kwon, S. Kidoaki, Photocurable biodegradable liquid copolymer: synthesis of acrylate-endcapped trimethylene carbonate-based prepolymers, photocuring and hydrolysis, Biomacromolecues, 10.1021/bm034231k, 5, 2, 295-305, 5、295-305 (2004)., 2004.01.
93. D. Umeno, M. Maeda, S. Kidoaki, and K. Yoshikawa, Temperature-directed compaction of single DNA molecule grafted with poly(N-isopropylacrylamide), Nucleic Acids Res. Symp. Ser., 39, 175-176 (1998)., 1998.01.
94. S. Kidoaki and K. Yoshikawa, Folding and Unfolding of a Giant Duplex-DNA in a Mixed Solution with Polycations, Polyanions, and Crowding Neutral Polymers, Biophys. Chem, 76, 133-143 (1999)., 1999.01.
95. S. Kidoaki and T. Matsuda, Adhesion Forces of the Blood Plasma Proteins on Self-Assembled Monolayer Surfaces of Alkanethiolates with Different Functional Groups Measured by an Atomic Force Microscope, Langmuir, 15, 7639-7646 (1999)., 1999.01.
96. T. Iwataki, Y. Yoshikawa, S. Kidoaki, D. Umeno, M. Kiji, M. Maeda, Cooperativity vs. Phase Transition in a Giant Single DNA Molecules, J. Am. Chem. Soc, 10.1021/ja000230d, 122, 41, 9891-9896, 122, 9891-9896 (2000)., 2000.01.
97. S. Kidoaki, Y. Nakayama, and T. Matsuda, Measuerment of Interaction Forces Between Proteins and Iniferter-Based Graft-Polymerized Surfaces with an Atomic Force Microscope in an Aqueous Media, Langmuir, 17, 1080-1087 (2001)., 2001.01.
98. S. Kidoaki, S. Ohya, Y. Nakayama, and T. Matsuda, Thermo-Responsive Property of N-isopropylacrylmide Graft-Polymerized Surfaces Measured with an Atomic Force Microscope, Langmuir, 17, 2402-2407 (2001)., 2001.01.
99. N. Yoshinaga, K. Yoshikawa, and S. Kidoaki, Multi-scaling in a long semi-flexible polymer chain in 2D, J. Chem. Phys., 10.1063/1.1475759, 116, 22, 9926-9929, 116, 9926-9929 (2002)., 2002.01.
100. S.G.Starodoubtsev, S.Kidoaki, K.Yoshikawa, Interaction of Double-stranded T4 DNA with Cationic Gel of Poly(Diallyldimethylammonium Chloride), Biomacromolecules, 10.1021/bm025583e, 4, 1, 32-37, 4, 32-37 (2003)., 2003.01.
101. T. Okuda, S. Kidoaki , M. Ohsakia, Y. Koyama, K. Yoshikawa, Time-dependent complex formation of dendritic poly(L-lysine)s with plasmid DNA and correlation with in vitro transfection efficiencies, Org. Biomol. Chem., 1, 1270-1273 (2003)., 2003.01.
102. Y. Nakayama, A. Furumoto, S. Kidoaki and T. Matsuda, Photocontrol of Cell Adhesion and Proliferation by a Photoinduced Cationic Polymer Surface, Photochem. Photobiol., 10.1562/0031-8655(2003)0772.0.CO;2, 77, 5, 480-486, 77(5), 480-486 (2003)., 2003.01.
103. T. Matsuda, J. Nagase, A. Gouda, Y. Hirano, S. Kidoaki, and Y. Nakayama, Phosphorylcholine-endcapped oligomer and block co-oligomer and surface biological reactivity, Biomaterials, 10.1016/S0142-9612(03)00344-2, 24, 24, 4517-4527, 24, 4517-4527 (2003)., 2003.01.
104. T. Yamaguchi, H. Otsuka, S. Kidoaki, T. Matsuda, A. Takahara, Physicochemical properties and bio-degradation of segmented polyurethane and poly(urethane-urea) derived from lysine-based diisocyanate, Trans. Mater. Res. Soc. Japan, 29 (6), 2873-2876 (2004)., 2004.01.
105. S Kidoaki, Y Nakayama, T Matsuda, Measurement of the interaction forces between proteins and iniferter-based graft-polymerized surfaces with an atomic force microscope in aqueous media, LANGMUIR, 10.1021/la000003p, 17, 4, 1080-1087, 2001.02, To investigate the characteristics of interaction forces between proteins and end-grafted polymer surfaces, force-versus-distance curves (f-d curves) were measured between protein-fixed probe tips (albumin (Alb) and lysozyme (Lyso)) and surfaces graft-polymerized with N,N-dimethylacrylamide (DMAAm) or acrylic acid (AAc) in an aqueous solution, using an atomic force microscope. DMAAm graft-polymerized surfaces with different chain lengths and AAc graft-polymerized surface were prepared by photopolymerization on a dithiocarbamate (iniferter)-immobilized surface. The effects of grafted chain length, grafting density, and electrostatic property of the grafted chain segments on the interaction forces in the processes of protein adsorption onto and desorption from the graft-polymerized surfaces were analyzed from the approaching and retracting traces of the observed f-d curves, respectively. (1) In the Alb/poly(DMAAm) system, steric repulsion was observed, in which the interaction range and the compressive force of the poly(DMAAm) layer linearly increased with increasing chain length of poly(DMAAm) except for very short chain lengths. Adhesion force was observed only for the poly(DMAAm) layer with short chains. (2) In the Alb/poly(AAc) system, repulsive force due to steric and electrostatic interactions, and "tooth-like" adhesion forces were observed. (3) In the Lyso/poly(AAc) system, electrostatic attraction and adhesion forces were observed. From observation 1, the grafting density, the elastic modulus of the poly(DMAAm) layer, and the conformation of the grafted chain ("mushroom" or "brush") were deduced and are discussed in relation to the characteristics of the interaction force with the proteins. From observations 2 and 3, it was found that a polyanionic surface can provide a significant adhesion force not only to positively charged proteins but also to negatively charged ones at physiological pH..
106. S Kidoaki, S Ohya, Y Nakayama, T Matsuda, Thermoresponsive structural change of a poly(N-isopropylacrylamide) graft layer measured with an atomic force microscope, LANGMUIR, 17, 8, 2402-2407, 2001.04, To directly characterize the thermoresponsive structural changes of a poly(N-isopropylacrylamide) (PNIPAAm) graft layer at the microscopic level, the force-distance curve (f-d curve) was measured on a well-tailored end-grafted PNIPAAm surface in aqueous solution at 25 and 40 degreesC, using an atomic force microscope (AFM). The PNIPAAm surface was prepared by an iniferter-based photograft polymerization technique. The approach trace of the f-d curve exhibited a steric repulsion profile at 25 degreesC, while the range of repulsion decreased 1/10 to 1/20 at 40 degreesC, confirming the ascending-heat induced collapse of the PNIPAAm graft layer. The change in thickness of the graft layer was complementarily measured from the scanning images of the boundary between the grafted and nongrafted regions under well-defined scanning forces. The thermoresponsive characteristics of the PNIPAAm graft layer including its interaction with proteins and the applied-load dependence of the measured graft thickness are discussed..
107. Application of Fluorescence Microscopy for the Single Molecular Observation of Giant Duplex DNA Chain.
108. S. Kidoaki and K. Yoshikawa, The Multistability Observed on the Condensed Structure of DNA/Cationic Polypeptide Complex, Nucleic Acids Res. Symp. Ser, 31, 183-184 (1994)., 1994.01.
109. T. Imae and S. Kidoaki, Solution Properties of Fibrous Chains Constructed of Amphiphilic Molecules, J. Jpn. Oil Chem. Soc. (YUKAGAKU), 44, 301-308 (1996)., 1995.01.
110. S. Kidoaki and K. Yoshikawa, The Folded State of Long Duplex-DNA Chain Reflects Its Solution History, Biophys. J., 71, 932-939 (1996)., 1996.01.
111. K. Yoshikawa, S. Kidoaki, M. Takahashi, V. V. Vasilevskaya and A. R. Khokhlov, Marked Discreteness on The Coil-Globule Transition of Single Duplex-DNA, Ber. Bunsen-Ges. Phys. Chem, 100, 876-880 (1996)., 1996.01.
112. H. Noguchi, S. Saito, S. Kidoaki and K. Yoshikawa, Self Organized Nanostructure Constructed with a Single Polymer Chain., Chem. Phys. Lett, 261, 527-533 (1996)., 1996.01.
113. S. Kidoaki and K. Yoshikawa, Controlling the Folding Transition of Giant DNA: Cooperative Effect Between Neutral Polymer and Basic polypeptide, Nucleic Acids Res. Symp. Ser, 35, 115-116 (1996)., 1996.01.
114. V. V. Vasilevskaya, A. R. Khokhlov, S. Kidoaki and K. Yoshikawa, Structure of Collapsed Persistent Macromolecule: Toroid vs. Spherical Globule, Biopolymers, 41, 51-60 (1997)., 1997.01.
115. N. Emi, S. Kidoaki, K. Yoshikawa and H. Saito, Gene Delivery Mediated by Polyarginine Requires a Formation of Big Carrier-Complex of DNA Aggregate, Biochem. Biophys. Res. Commun, 231, 421-424 (1997)., 1997.01.
116. T. Kuboki, F. Kantawong, R. Burchmore, M.J. Dalby, and S. Kidoaki, 2D-DIGE proteomic analysis of mesenchymal stem cell cultured on the elasticity-tunable hydrogels, Cell Structure and Function, 37, 127-139,2012..