Language：English   Publishing type：Research paper (scientific journal)  

This paper proposes microfluidic particle separation by sheath-free deterministic lateral displacement (DLD) with inertial focusing in a single straight input channel. Unlike conventional DLD devices for size- based particle separation, in which sheath streams are used to focus the particles before the solution containing them reaches the DLD arrays, the proposed method uses inertial focusing to align the particles along the middle or the sidewalls of the straight rectangular input channel. The two-stage model of inertial focusing is applied to reduce the length of the side-focusing channel. The proposed method is demonstrated by using it to separate fluorescent polymer particles of diameters 13 and 7 μm, in the process of which the effect of the particle focusing regime on the separation performance is also investigated. Through middle focusing, the method is further used to separate MCF-7 cells (a model of circulating tumor cells (CTCs)) and blood cells, with ∼99.0% capture efficiency achieved.

DOI： 10.1039/d0lc00354a

Language：English   Publishing type：Research paper (scientific journal)  

Alginate-based hydrogels are widely used in the biomedical and chemical fields, and their size and shape are significant to their applications like drug delivery and cell encapsulation. Here, we report a microfluidic external gelation process using an on-chip calcium chloride (CaCl₂) emulsion reactant for producing highly spherical calcium alginate (Ca-alginate) hydrogel particles. The microfluidic channels were two serial cross-junctions fabricated on quartz glass. Monodisperse sodium alginate (Na-alginate) droplets with diameters greater or smaller than the opening (ranging from 176 μm to 225 μm) with a coefficient of variation (CV) less than 3% were successfully generated at the upstream cross-junction; they then reacted with the CaCl₂ emulsion at the downstream cross-junction, forming Ca-alginate hydrogels. The effects of the fraction of the aqueous phase in the reactant CaCl₂ emulsion and the flow rates of continuous and emulsion phases on the roundness of the obtained hydrogels were studied. By optimizing the parameters above, monodisperse spherical hydrogel particles were obtained with diameters ranging from 147 μm to 176 μm with CVs around 5%. The synthesis of magneto-responsive hydrogels with asymmetric Fe₃O₄ coatings was also demonstrated.

DOI： 10.1016/j.snb.2018.12.101

Language：English   Publishing type：Research paper (scientific journal)  

In this work, degas-driven microfluidic deterministic lateral displacement devices were fabricated from poly(dimethylsiloxane). Two device configurations were considered: One with a single input for the enrichment of particles and the other one with sheath inputs for the separation of particles based on their sizes. Using the single-input device, the characteristics of the degas-driven fluid through micropillars were investigated, and then selective enrichment of fluorescent polymer particles with diameters of around 13 μm mixed with similar 7 μm particles was demonstrated. Using the sheath-input device, the separation of 13 and 7 μm beads was achieved (the corresponding purities exceeded 92.62% and 99.98%, respectively). In addition, clusters composed of 7 μm beads (including doublets, triplets, and quadruplets) were fractionated based on their equivalent sizes. Finally, white blood cells could be separated from red blood cells at a relatively high capture efficiency (95.57%) and purity (86.97%).

DOI： 10.1021/acs.analchem.8b05587

Language：English   Publishing type：Research paper (scientific journal)  

We present a parallel numbering-up device for microfluidic production of satellite droplet-free emulsions. The device consists of two stacked layers made of polydimethylsiloxane (PDMS). The bottom layer combines eight parallel sets of a microfluidic droplet generator (MFDG) and deterministic lateral displacement (DLD) array for size-based separation of main and satellite droplets. The top layer has input reservoirs to supply both the disperse and continuous phases evenly to the eight channels of the bottom layer. We employed 3D flow simulations to find the reservoirs most suitable for equal inflow distribution. Water-in-oil (W/O) droplets comprised of main droplets (∼67 μm in diameter) and satellite droplets (1–20 μm) were generated in the parallelized MFDGs, and they were then completely separated through the DLD arrays having a critical diameter of D_c = 37.1 μm. Thus, we confirmed production of satellite droplet-free emulsion droplets at 0.2 ml/h, eight times the processing throughput of single device (= 0.025 ml/h) without decrease in performance.

DOI： 10.1016/j.snb.2018.01.112

Language：English   Publishing type：Research paper (scientific journal)  

A microfluidic droplet generator (MFDG) normally produces satellite droplets through break-off from the main droplet because of the Plateau-Rayleigh instability, resulting in contamination and/or poor size distribution of the products. Thus, we herein demonstrate the continuous, passive, and size-based separation of main and satellite droplets using the deterministic lateral displacement (DLD) array method. For the purpose of this study, we designed and employed microfluidic devices comprised of an upstream symmetric flow-focusing MFDG and a downstream DLD array composed of polydimethylsiloxane (PDMS). Initially, we produced water-in-oil (W/O) droplets containing main droplets of ∼61.1 μm diameter in addition to satellite droplets of 1-30 μm diameter in a hydrophobic MFDG, and we report the successful separation of the main and satellite droplets through a single-step DLD array with a critical diameter (D_c) of 37.1 μm. Furthermore, we demonstrated the generation and separation of single-phase or biphasic (i.e. Janus or core-shell) oil-in-water (O/W) main and satellite droplets using a hydrophilic MFDG and a DLD array. Finally, in addition to the removal of main and satellite W/O droplets, we also fractionated satellite droplets of different sizes into three groups (i.e., 21.4, 10.1, and 4.9 μm average diameter) using a device with three-step DLD arrays each having different D_c values (i.e., 37.1, 11.6, and 7.0 μm).

DOI： 10.1039/c7ra05852g

Repository Public URL： https://hdl.handle.net/2324/7174481

Language：English   Publishing type：Research paper (scientific journal)  

Here, we present a deterministic lateral displacement (DLD) microfluidic device that may be used for label-free, passive, and continuous separation of viable and nonviable mammalian cells. Cells undergoing apoptosis (programmed cell death) become smaller than normal viable cells due to shrinkage and fragmentation. We used this distinct difference in size to selectively isolate viable Jurkat cells from nonviable apoptotic cells and their remnants through a DLD array that is capable of size-based fractionation of microparticles. First, we calibrated our DLD devices by separating a mixture of larger (~15-μm) and smaller (~8-or ~10-μm) polystyrene beads that emulated viable and nonviable Jurkat cells, respectively. We then demonstrated the separation of viable and nonviable Jurkat cells by introducing their heterogeneous suspensions into two DLD devices with different design parameters. In a DLD device with a 20-μm gap, we collected viable cells at 100 ± 0% capture efficiency (n = 3), at a capture purity of 23.1 ± 4.8%, with 57.8 ± 8.1% removal efficiency of nonviable apoptotic cells and their remnants from the initial mixture solution. On a DLD device with a 23-μm gap, the capture purity of viable cells increased to 50.2 ± 15.0%, with 89.0 ± 3.5% removal efficiency of nonviable cells, and a lower capture efficiency of 48.2 ± 2.0% (n = 3). This first demonstration of label-free and passive separation of viable and nonviable cells by DLD illustrates its potential for, e.g., regenerative medicine and discovery of anti-cancer drugs.

DOI： 10.1063/1.4942948

Event date： 2023.6

Language：English  

Venue：Kyoto   Country：Japan  

Event date： 2023.6

Language：English  

Venue：Kyoto   Country：Japan  

Event date： 2023.6

Language：English  

Venue：Kyoto   Country：Japan  

Event date： 2023.6

Language：English  

Venue：Kyoto   Country：Japan  

Event date： 2023.1

Language：English  

Venue：Science Congress Center Munich   Country：Germany  

Event date： 2022.10

Language：English  

Venue：Online   Country：Japan  

Event date： 2022.10

Language：English  

Venue：Online   Country：Japan  

Event date： 2022.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Philadelphia (PA), USA (& Online)   Country：United States  

Event date： 2022.5

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：中央大学（東京，ハイブリッド）   Country：Japan  

Event date： 2021.10

Language：English  

Venue：Online   Country：Japan  

Event date： 2021.1

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：Japan  

Event date： 2020.10

Language：English  

Venue：Online   Country：Japan  

Event date： 2018.11

Language：English  

Venue：Kaohsiung   Country：Taiwan, Province of China  

We report degas-driven deterministic lateral displacement (DLD) for size-based particles enrichment and separation by using polydimethylsiloxane (PDMS) gas solubility. Unlike conventional DLDs which normally require external pumping equipment, we have employed degas-driven flow of a PDMS device to infuse a sample solution into a DLD array. We have demonstrated DLD-based enrichment and separation of differently sized microbeads. Furthermore, separation of white blood cells (WBCs) and red blood cells (RBCs) in whole blood was also demonstrated.

Event date： 2018.11

Language：English  

Venue：Kaohsiung   Country：Taiwan, Province of China  

We propose novel deterministic lateral displacement (DLD) devices that enable separation and reaction simultaneously for producing functional particles. Firstly, we produced spherical Ca-alginate gel particles without satellite droplets by producing and transporting Na-alginate droplets across the CaCl₂ emulsion stream through DLD micropillars. We also demonstrate polyelectrolyte coating onto polystyrene microspheres using multiple laminar streams flowing through DLD micropillars.

Event date： 2017.10

Language：English  

Venue：Savannah   Country：United States  

We report sheath-free deterministic lateral displacement (DLD) for size-based particles separation by using inertial focusing in a single input stream. Unlike conventional DLDs which require sheath streams to focus a particles-containing solution before DLD arrays, we have employed inertial focusing to align particles along the center or sidewalls of the input channel. We have demonstrated inertial focusing and DLD-based separation of differently sized microbeads.

Event date： 2017.10

Language：English  

Venue：Savannah   Country：United States  

We present sheathless deterministic lateral displacement (DLD) for particles separation by using elasto-inertial focusing in a single input stream. Instead of conventional DLDs which require sheath buffer streams to focus a particles-containing sample solution before DLD arrays, we have employed elasto-inertial focusing to align particles along an input channel center line. We have demonstrated successful elasto-inertial focusing and microbeads separation based on their sizes in the DLD array.

Event date： 2016.10

Language：English  

Venue：Dublin   Country：Ireland  

We present a novel deterministic lateral displacement (DLD) microfluidic device with thermally tunable separation capability. To flexibly change the critical diameter (Dc) of the separation array, we fabricated DLD micropillars made of poly-N-isopropylacrylamide, a thermo-responsive hydrogel, in a polydimethyl siloxane microfluidic channel. The prepared DLD pillars shrunk at a high temperature (>30°C) and swelled at a low temperature (<30°C) in an aqueous solution because of their characteristic hydrophilic-hydrophobic phase transitions. By heating and cooling the DLD device across the transition temperature, the D_ccould be continuously changed and the separation mode of the model particles could be switched.

Event date： 2016.10

Language：English  

Venue：Dublin   Country：Ireland  

We report the continuous and passive separation of main and satellite droplets using a deterministic lateral displacement (DLD) array coupled with a symmetric microfluidic droplet generator. In addition to the collection of the main water-in-oil droplets at 100% purity, fractionation of satellite populations of different sizes could be achieved through the multi-step hydrophobic DLD regions. Moreover, separation of main and satellite biphasic oil-in-water droplets was successfully demonstrated using a hydrophilic DLD device. To the best of our knowledge, this is the first report on the microfluidic separation of main and satellite droplets produced in a purely symmetric system.

Event date： 2015.10

Language：English  

Venue：Gyeongju   Country：Korea, Republic of  

We report the first use of deterministic lateral displacement (DLD) microfluidic device for label-free separation of viable cells from nonviable cells. Cells in apoptosis status are physically smaller than viable cells. We focused on this phenomenon and have demonstrated the separation of viable cells from nonviable cells using DLD method, which can separate particles based on their sizes continuously without any labeling and external energy sources. We succeeded in the removal of 66.9% nonviable cells and also enrichment of viable cells.

Event date： 2023.11

Language：English  

Venue：Nagoya University   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：熊本城ホール（熊本）   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：熊本城ホール（熊本）   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：熊本城ホール（熊本）   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：熊本城ホール（熊本）   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：熊本城ホール（熊本）   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：熊本城ホール（熊本）   Country：Japan  

Event date： 2023.6 - 2023.7

Language：Japanese  

Venue：名古屋国際会議場（愛知）   Country：Japan  

Event date： 2023.6 - 2023.7

Language：Japanese  

Venue：名古屋国際会議場（愛知）   Country：Japan  

Event date： 2023.6 - 2023.7

Language：Japanese  

Venue：名古屋国際会議場（愛知）   Country：Japan  

Event date： 2023.6 - 2023.7

Language：Japanese  

Venue：名古屋国際会議場（愛知）   Country：Japan  

Event date： 2023.6 - 2023.7

Language：Japanese  

Venue：名古屋国際会議場（愛知）   Country：Japan  

Event date： 2023.6 - 2023.7

Language：Japanese  

Venue：名古屋国際会議場（愛知）   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：日立システムズホール（宮城）   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：日立システムズホール（宮城）   Country：Japan  

Event date： 2023.5

Language：Japanese  

Venue：東北大学川内キャンパス   Country：Japan  

Event date： 2023.5

Language：Japanese  

Venue：東北大学川内キャンパス   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学 六甲台第二キャンパス   Country：Japan  

Event date： 2022.11

Language：Japanese  

Venue：アクティとくしま   Country：Japan  

Event date： 2022.11

Language：Japanese  

Venue：アクティとくしま   Country：Japan  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡国際会議場   Country：Japan  

Event date： 2022.6

Language：Japanese  

Venue：福岡国際会議場   Country：Japan  

Event date： 2022.6

Language：Japanese  

Venue：札幌コンベンションセンター   Country：Japan  

Event date： 2022.5

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2022.5

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.12

Language：English  

Venue：Online   Country：Japan  

Event date： 2021.11

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.11

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.11

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.11

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.5

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2020.11

Language：English  

Venue：Online   Country：Japan  

Event date： 2020.10

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.10

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.10

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2018.11

Language：English  

Venue：Kaohsiung   Country：Taiwan, Province of China  

We propose a novel concept, Soft Step Emulsification (SSE): actively-tunable geometry-dependent droplet generation in an elastic device. By mechanically stretching a whole device made of polydimethylsiloxane (PDMS), we induce deformation of internally confined micro nozzles, tuning the droplet break-off in step emulsification. The shrinkage/expansion of the nozzles could be switched when changing directions of stretching by 90°, allowing us to flexibly tune the sizes of water-in-oil (W/O) droplets in the combined range of 9-18 µm with CVs of 5-8%.

Event date： 2018.11

Language：English  

Venue：Kaohsiung   Country：Taiwan, Province of China  

We propose a simple droplet-production module with grooves crossing over slits. Our test modules consist of two detachable elements: (a) a PDMS chip with microfabricated open grooves with matrix or circular arrangement, and (b) stainless-steel parts with three linear or annular parallel slits for world-to-chip interface. By assembling the two elements so that the on-chip microgrooves cross over the slits, we demonstrated parallelization of 100–1250 microfluidic droplet generators (MFDGs) of 10–100 μm sizes for mass-producing water-in-oil (W/O) droplets.

Event date： 2018.11

Language：English  

Venue：Kaohsiung   Country：Taiwan, Province of China  

We report microfluidic in-situ external gelation for preparing calcium(Ca)-alginate hydrogels of precisely defined shapes for controlled drug release. We demonstrated that homogeneous spatial distribution of reactant CaCl₂emulsions around precursor sodium(Na)-alginate droplets is essential to obtain highly spherical hydrogels. UV-Vis measurement was performed to demonstrate sustained release of encapsulated anti-fouling drug Irgarol. Magneto-responsive Janus gels and hemi-spherical gels made from Na-alginate/Grycerol Janus droplets are also presented.

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Internal/External technical report, pre-print, etc.  

DOI： 10.1541/ieejsmas.143.NL2_1

Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： https://doi.org/10.3390/mi13030482

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： 10.3390/mi11060602