論文 - 三木　則尚

In vitro and in vivo tests of nanoporous membrane coated with biocompatible fluorine-doped diamond-like carbon for hemofiltration treatment

Ota T., Nakayama M., Kanno Y., Suzuki T., Miki N.

Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) （Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)）  2018-January   412 - 414 2018年04月

ISSN  9781538647820

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© 2018 IEEE. In this report, we experimentally investigated the blood hemofiltration capacity of a nanoporous dialysis membrane (poly(ether sulfone), PES) whose surface was modified with fluorine-doped diamond-like carbon(f-DLC). Surface modification of the nanoporous membrane without clogging the nanopores is challenging. In vitro experiments revealed that the modified membrane successfully exhibited water permeability of one-tenth of the untreated. In vivo experiments with ultra-small hemofiltration devices composed of f-DLC PES membranes using SD rats were also conducted for the first time. The results proved that the f-DLC coated PES membrane can be used for hemofiltration, which will extend the lifetime of microfluidics-based implantable artificial kidney.

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Handheld nanopore-based biosensing device

Izawa Y., Osaki T., Kamiya K., Fujii S., Misawa N., Miki N., Takeuchi S.

Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) （Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)）  2018-January   2 - 5 2018年04月

ISSN  9781538647820

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© 2018 IEEE. This paper describes the development of a handheld device for long-term nanopore-based biosensing. Recently, membrane protein reconstituted in bilayer lipid membrane (BLM) has been applied for bio/chemical sensors because membrane protein intrinsically has a superior amplification mechanism. For mobile use of such devices, however, the bilayer requires mechanical robustness. Here, we propose a handheld BLM device aiming for a nanopore-based mobile sensor. BLM is formed at the tip of a glass capillary, which is contained in the solution trapped in a cup-like reservoir. This format achieved (i) formation of a sufficiently robust BLM for mobile use, (ii) solution exchange without rupturing BLM, and (iii) sustaining the small number of nanopores in the bilayer for accurate and long-term sensing. The handheld device successfully detected DNA translocations through the nanopores continuously for 75 minutes using 5 nanopores.

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Well-Controlled Cell-Trapping Systems for Investigating Heterogeneous Cell–Cell Interactions

Kamiya K., Abe Y., Inoue K., Osaki T., Kawano R., Miki N., Takeuchi S.

Advanced Healthcare Materials （Advanced Healthcare Materials）  7 （ 6 ）  2018年03月

ISSN  21922640

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© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Microfluidic systems have been developed for patterning single cells to study cell–cell interactions. However, patterning multiple types of cells to understand heterogeneous cell–cell interactions remains difficult. Here, it is aimed to develop a cell-trapping device to assemble multiple types of cells in the well-controlled order and morphology. This device mainly comprises a parylene sheet for assembling cells and a microcomb for controlling the cell-trapping area. The cell-trapping area is controlled by moving the parylene sheet on an SU-8 microcomb using tweezers. Gentle downward flow is used as a driving force for the cell-trapping. The assembly of cells on a parylene sheet with round and line-shaped apertures is demonstrated. The cell–cell contacts of the trapped cells are then investigated by direct cell–cell transfer of calcein via connexin nanopores. Finally, using the device with a system for controlling the cell-trapping area, three different types of cells in the well-controlled order are assembled. The correct cell order rate obtained using the device is 27.9%, which is higher than that obtained without the sliding parylene system (0.74%). Furthermore, the occurrence of cell–cell contact between the three cell types assembled is verified. This cell-patterning device will be a useful tool for investigating heterogeneous cell–cell interactions.

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Three-dimensional rotation/translation microfluidic devices for sequential mixing

Tachibana T., Kamiya K., Osaki T., Misawa N., Fujii S., Miki N., Takeuchi S.

22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018 （22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018）  1   309 - 310 2018年

ISSN  9781510897571

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Copyright© (2018) by Chemical and Biological Microsystems Society.All rights reserved. This paper demonstrates a three-dimensional microfluidic device for sequence-controlled mixing of solutions. First, we designed and fabricated the device. The major characteristics of the device are pumpless and having three-dimensional network and mechanical components (rotate and translate) to control the fluidic paths. We injected four different solutions to each inlet of the device and generated the mixed three solutions in the designated orders by rotating and sliding the device. Successful parallel and sequential mixing was verified.

Improvement of microtas for directed evolution of NAD(P)-dependent oxidoreductases

Goto H., Kanai Y., Yotsui A., Shimokihara S., Shitara S., Einaga Y., Matsumoto Y., Miki N., Fujiwara K., Doi N.

22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018 （22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018）  4   2247 - 2249 2018年

ISSN  9781510897571

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Copyright © (2018) by Chemical and Biological Microsystems Society. All rights reserved. Here we report an improved μTAS based on electrochemical measurements and microbeads sorting for screening of NAD(P)-dependent oxidoreductases. By using this system, we measured the activity of model enzymes immobilized on microbeads by detection of NADH with a boron-doped diamond (BDD) electrode in each compartment (∼30 nL) of the microfluidic system. Then, we recovered the magnetic microbeads or the droplets containing genes of enzymes with higher activity by magnetophoretic or dielectrophoretic sorting, respectively. Our μTAS should be useful for directed evolution of various NAD(P)-dependent oxidoreductases with high activity and stability in the future.