担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Canada   Vancouver   2020年01月18日  -  2020年01月22日

© 2020 IEEE. We developed a MEMS based sensor, Nanopin, for mechanical characterization of individual adherent cells. Nanopin consists of sensing tip that forms a contact with a cell, a displacement sensor, and an actuator. The feasibility of sensing was evaluated using various concentrations of agarose gel, and then the stiffness measurements of human carcinoma cells were conducted on different surfaces. After the measurements of cells, we confirmed that cells grow normally in an incubator.

DOI： 10.1109/MEMS46641.2020.9056113

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Switzerland   Basel   2019年10月27日  -  2019年10月31日

© 2019 CBMS-0001. This paper reports an original approach to assess the effects of DNA binding agents on the physical properties of DNA in nucleus-like conditions. We are using Silicon Nanotweezers (SNT), to monitor the stiffness of phage-λ DNA through increasing concentrations of Doxorubicin, SybrGreen and Hoechst in real-time. We show that Doxorubicin and Hoechst lead to an increase in the stiffness of the DNA until a critical concentration where the hydrogen bonds between the complementary base pairs are perturbed, causing the denaturation of the molecule and reducing the stiffness of the structure, while the SybrGreen decreases the stiffness.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1063/1.5125650

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2018 The Author(s). The couple Calix[4]arene-1,3-O-diphosphorous acid (C4diP) and zinc ions (Zn2+) acts as a synergistic DNA binder. Silicon NanoTweezer (SNT) measurements show an increase in the mechanical stiffness of DNA bundles by a factor of >150, at Zn2+ to C4diP ratios above 8, as compared to Zinc alone whereas C4diP alone decreases the stiffness of DNA. Electroanalytical measurements using 3D printed devices demonstrate a progression of events in the assembly of C4diP on DNA promoted by zinc ions. A mechanism at the molecular level can be deduced in which C4diP initially coordinates to DNA by phosphate-phosphate hydrogen bonds or in the presence of Zn2+ by Zn2+ bridging coordination of the phosphate groups. Then, at high ratios of Zn2+ to C4diP, interdigitated dimerization of C4diP is followed by cross coordination of DNA strands through Zn2+/C4diP inter-strand interaction. The sum of these interactions leads to strong stiffening of the DNA bundles and increased inter-strand binding.

DOI： 10.1038/s41598-019-42267-x

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Taiwan   Kaohsiung   2018年11月11日  -  2018年11月15日

Copyright © (2018) by Chemical and Biological Microsystems Society. All rights reserved. The development of Silicon Nano-Tweezers (SNTs) along with associated micro-fluidics allows the study of how interactions between DNA and external modifiers change the mechanical properties of DNA. This innovative methodology allows direct observation of the effects of Supramolecular Epigenetics, in which bio-active systems interact non-covalently with DNA. Here Silver ions were found to strongly stiffen DNA bundles, microscope studies showed clumping along the DNA. From here micro-tweezers were prepared allowing crystal growth on DNA strands. Small crystals ca 10 μm formed; EDS and X-rays studies imply that these crystals may be a polymorph of the normal form of silver nitrate.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Taiwan   Kaohsiung   2018年11月11日  -  2018年11月15日

Copyright © (2018) by Chemical and Biological Microsystems Society. All rights reserved. This paper reports the advantages to use a MEMS based device consisting of Silicon Nano Tweezers (SNTs) for trapping DNA at high molecular density and monitoring its mechanical effects under an enzymatic reaction. DNA digestion assays have been performed with a Type 2 endonuclease either in solution at low DNA density (≈1x105 bp/µm3) or trapped by SNTs at high DNA density (≈1x107 bp/µm3). Unexpectedly, when DNA is trapped between the tweezers tips, the nuclease behaves differently. The enzyme is not able to digest the DNA but increases its stiffness and viscous losses under the crowded environment provided by the SNTs.

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記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

© 2018 The Institute of Electrical Engineers of Japan. This paper describes a microfluidic device for observation of cancer cell invasion induced by chemotaxis. The developed device has two main-channels, the channel filled with cell suspension and the channel filled with solution containing chemotactic factor. These channels are connected via tapered orifice structures to capture multiple cancer cells in it to form cell clusters. Observation of cell invasions affected by cell adhesions is possible with this device. The devices were fabricated by using three-dimensional lithography and PDMS (polydimethylsiloxane) molding. Invasion cells leaving the cell clusters and moving to the channel containing chemotactic factors through the orifices were successfully observed on the device.

DOI： 10.1541/ieejsmas.138.435

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.3390/mi9060275

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Northern Ireland   Belfast   2018年01月21日  -  2018年01月25日

© 2018 IEEE. The mechanical properties of cells have been suggested as alternative biomarkers; however, there is no practical high-throughput and high information content measurement technique applicable for non-adherent cells. To address this problem, we propose a MEMS-based device with an embedded microfluidic channel. Cells flow inside the channel individually and position directly at a sensing area. Then, developed LabVIEW program applies compression cycles to the cell and detects the mechanical properties of the cell in real-time. At the same time, the electrical measurements are performed. Due to direct measurements, we can simplify the experimental setup and improve the throughput compared to the conventional high information content techniques, e.g. AFM. This technique leads to a promising alternative way to identify non-adherent rare cells, e.g. circulating tumor cells and cancer stem cells.

DOI： 10.1109/MEMSYS.2018.8346544

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1038/s41598-018-19712-4

記述言語：フランス語   掲載種別：研究論文（学術雑誌）

DOI： 10.1051/medsci/20173312003

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

USA   Georgia   2017年10月22日  -  2017年10月26日

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2017 IEEE. This study presents a practical method to perform mechanical characterization of cells using Silicon Nano Tweezers (SNT). Integrated with a microfluidic device, SNT tips were inserted in a channel via a side opening. Cells to be characterized were injected to an inlet of the microfluidic channel and withdrawn by a vacuum pump connected to an outlet. Mechanical properties of a cell, e.g. diameter, stiffness and viscous losses, were analyzed after capturing between the SNT tips (a sensing tip and a compressing tip). After characterization, the captured cell was released to capture another cell. Repeated capturing and characterization steps allow us to test several cells and distinguish fixed and live SUM-159-PT cancer cells based on their mechanical properties.

DOI： 10.1109/MEMSYS.2017.7863481

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2017 The Institute of Electrical Engineers of Japan. In this paper, we report on a proof-of-concept level energy harvester device that could earn electric power of 0.093 μW/cm2 by the fluidic motion in a PDMS (polydimethylsiloxane) micro fluidic channel placed on a silicon substrate with built-in permanent electrical charges or so-called electrets. Targeting implantable medical devices such as respiratory pace-maker, the heart beat or aspiration is thought to be the source of motion as a final shape of the energy harvesting system.

DOI： 10.1541/ieejsmas.137.152

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© Published under licence by IOP Publishing Ltd. Targeting implantable medical devices such as respiratory pace-maker, we have developed a proof-of-concept level energy harvester device that could earn electric power of 44 μW/cm2 by the fluidic motion in a PDMS microchannel placed on a silicon substrate with built-in permanent electrical charges or so-called electrets. The motion of the working fluid will be operated by the heart beat or breathing as a final shape of the energy harvesting system.

DOI： 10.1088/1742-6596/773/1/012078

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Kanazawa   2016年06月26日  -  2016年06月29日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1039/C6LC00309E

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Seoul   Korea   2016年04月20日  -  2016年04月22日

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2016 IEEE. This paper reports a novel approach to scan with a high resolution the relative humidity around water in microsized environment. The humidity sensor is composed of a MEMS device, the Silicon Nano Tweezers (SNT) and a DNA bundle. The principle of the measurement is based on the relation between the electro-mechanical properties (conductance and stiffness) of a DNA bundle and the relative humidity. The system is developed to obtain precisely, quickly, and automatically the middle of the aperture of a microfluidic cavity for self-alignment purpose.

DOI： 10.1109/MEMSYS.2016.7421613

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© The Author(s) 2016. The killing of tumor cells by ionizing radiation beams in cancer radiotherapy is currently based on a rather empirical understanding of the basic mechanisms and effectiveness of DNA damage by radiation. By contrast, the mechanical behaviour of DNA encompassing sequence sensitivity and elastic transitions to plastic responses is much better understood. A novel approach is proposed here based on a micromechanical Silicon Nanotweezers device. This instrument allows the detailed biomechanical characterization of a DNA bundle exposed to an ionizing radiation beam delivered here by a therapeutic linear particle accelerator (LINAC). The micromechanical device endures the harsh environment of radiation beams and still retains molecular-level detection accuracy. In this study, the first real-time observation of DNA damage by ionizing radiation is demonstrated. The DNA bundle degradation is detected by the micromechanical device as a reduction of the bundle stiffness, and a theoretical model provides an interpretation of the results. These first real-time observations pave the way for both fundamental and clinical studies of DNA degradation mechanisms under ionizing radiation for improved tumor treatment.

DOI： 10.1038/micronano.2016.62

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1016/j.sse.2015.08.019

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2015 IEEE. We report the first real-time biomechanical measurement of DNA bundle degradation in stable condition when exposed to a therapeutic radiation beam and a theoretical model to describe DNA damages. The Silicon Nano Tweezers and their new microfluidic system endure the harsh environment of radiation beams and still retain molecular-level accuracy. This result paves the way for both fundamental and clinical studies of DNA degradation under radiation for improved tumor treatment.

DOI： 10.1109/TRANSDUCERS.2015.7180864

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記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper presents an innovative versatile method aiming at rapid fabrication of a master for polydimethylsiloxane (PDMS) molding. This technology is relying on liquid dielectrophoresis electromechanical microfluidic transduction for programmable ultraviolet (UV) glue manipulation. It enables formation of the master in a tailor-made approach, avoiding the need of micromachined structures unlike in conventional methods. The principle is simple: UV glue, while in liquid phase, is actuated onto an array of electrodes patterned on a Si substrate and cured afterward by UV exposure. The silicon chip and the glue microstructures defined atop of it then play the role of a master for PDMS molding. The glue microstructures' shape is hemispherical which is of high interest for many microfluidic applications. This concept is assessed and validated with two different PDMS chip replica designs, both of them illustrating representative applications in continuous microfluidic: a T-junction design for inflow droplet generation and a "Quake" type valve. Lastly, this protocol has shown to be recyclable since the UV glue microstructures once formed can be easily removed by immersion in an acetone bath, such as the chip is reset and can be reprogrammed afterward to build another glue channels geometry. © 2013 European Union.

DOI： 10.1007/s10404-013-1256-z

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

We have developed a membrane-less pressure sensor based on squeeze-film damping in a 2-μm driving/sensing gap of a silicon ring-shaped resonator. Its sensing range is from sub-atmospheric to over 1MPa; very wide-range pressure measurement is possible with one sensor element. An electret film having the 200-V-bias voltage was incorporated to the resonator; this allows the excitation of the resonator at very low AC voltage. This membrane-less pressure sensor has robust and low power consumption (nW-range) characteristics. © 2014 IEEE.

DOI： 10.1109/MEMSYS.2014.6765741

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

A new and original concept aiming at rapid fabrication of continuous microfluidic chips with a channel-based reconfigurable and programmable geometry is reported in this paper. Interfaces between DI water and liquid paraffin-wax are precisely controlled using electromechanical forces onto an array of electrodes, similar to classical digital microfluidic platforms. As the liquid-liquid interfaces define the targeted geometry, the paraffin is solidified by decreasing the chip temperature using an integrated thermoelectric cooler. Then, the paraffin channel-based chip is used for in-flow continuous microfluidic experiments. First results describing the whole concept are shown with typical fluidic geometries. © 2013 IEEE.

DOI： 10.1109/Transducers.2013.6627238

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this work we show that implementation of closed-loop control to silicon nanotweezers improves the sensitivity of the tool for mechanical characterization of biological molecules. Micromachined tweezers have already been used for the characterization of mechanical properties of DNA molecules [1] as well as for the sensing of enzymatic reactions on DNA bundle [2], [3]. However the resolution of the experiments does not allow the sensing on single molecules. Hereafter we show theoretically and experimentally that, reducing the resonance frequency of the system by the implementation of a state feedback, the sensitivity to stiffness variation is enhanced. Such improvement leads to better resolution for detection of enzymatic reactions on DNA [4]. © 2013 IEEE.

DOI： 10.1109/IROS.2013.6696476

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This work has achieved the control of micromachined tweezers for the enhancement of the sensing of DNA molecules. The tool allows a routine trapping of the molecules and the real-time monitoring of the mechanical properties of the bundle of molecules. Monitoring the resonance response of the system, the bundle and the interactions of enzymes or proteins are characterized. Furthermore the design and the implementation of state feedback decrease the equivalent stiffness of the system and improve the sensitivity of the tool. © 2013 IEEE.

DOI： 10.1109/Transducers.2013.6627279

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this research, we demonstrate for the first time the in-situ polymerization and the mechanical characterization of metallopolymer wires by MEMS Silicon Nanotweezers. Metallopolymers have interesting semiconductor characteristics that can be tuned by polymerization conditions. The reported method allows the experiment of various polymerization conditions with a high versatility such as the metallopolymer properties (electrical, mechanical, and piezoresistive) can be studied and optimized rapidly on demand. © 2013 IEEE.

DOI： 10.1109/Transducers.2013.6627359

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

We report the biomechanical characterization of λ-DNA bundle exposed to a therapeutic radiation beam by silicon Nanotweezers. The micromechanical device endures the harsh environment of radiation beams, and still retains molecular-level detection accuracy. The real-time DNA bundle degradation is observed in terms of biomechanical stiffness and viscosity reduction, both in air and in solution. These results pave the way for both fundamental and clinical studies of DNA degradation mechanisms under ionizing radiation for improved tumor treatment. © 2013 IEEE.

DOI： 10.1109/EMBC.2013.6611123

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper describes an integrated biomechanical platform for real-time molecular or cellular assays. This platform is composed of silicon nanotweezers to manipulate the biological samples and an open microfluidic to handle solution and reactive agents. The tweezers are fabricated by standard Silicon-On-Insulator based micromachining processes (2 masks +1 additional mask for special tips) and integrate actuator, trapping tips and sensor. The microfluidic device is produced from common polydimethylsiloxane (PDMS) micromolding and integrates active valves for controlling the biological medium. Combining both technologies, a versatile experimental setup, built up in an enclosed space (< 10 cm3), enables direct interrogation of molecules or cells in solution. The silicon nanotweezers sense slight biological modifications of the trapped molecules or cell by monitoring the mechanical resonance response, which keeps a high Q factor (over 20) in liquid. Biomolecular assays (molecule trapping and enzymatic reaction kinetics) as well as characterizations of cells are reported here. The system provide molecular level resolution and is sensitive enough to capture cell biomechano-transduction activities. Moreover as the system is handy, it may be an easy, fast and quantitative alternative to existing methods. © 2013 IEEE.

DOI： 10.1109/EMBC.2013.6609459

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1039/C3RA40700D

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1007/s10404-013-1156-2

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1541/ieejsms.133.98

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1016/j.drudis.2013.02.002

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

We report the first real-time biomechanical measurement of DNA bundle degradation in solution when exposed to a therapeutic radiation beam. The Silicon Nano Tweezers and their microfluidic endure the harsh environment of radiation beams and still retain molecular-level accuracy. This result paves the way for both fundamental and clinical studies of DNA degradation under radiation for improved tumor treatment.

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

We performed electrical and mechanical characterization of single stranded DNA (ssDNA) bundle generated on the tips of a micromachined silicon nanotweezers (SNT) via isothermal rolling circle amplification (RCA; Fig 1). Primers with 7 nm length (21 nts) were amplified and final length of amplified product became longer than 2.5 μm. Generated ssDNA bridge between tips which were formed by dielectrophoresis (DEP) was easily visualized and detected via conductivity and resonance frequency (Fres) measurements. These data provides a "proof-of-principle " for the feasibility of the on-chip label free DNA detection device that can be used for a variety of biomedical applications.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper reports a new protocol on-chip for functionalization purpose enabled by liquid dielectrophoresis (LDEP) technique at the microscale, and its adaptation to the nanoscale for the MEMS/NEMS applications. In a previous study, circular spots (diameter: 25-100 μm), made of polymer, have been accurately positioned onto a surface using LDEP. In this study, doped polysilicon LDEP structures have been fabricated with submicronic electrodes widths, to displace weak amount of liquids and create femtoliter sessile droplets. The final goal consists in dispensing fL droplets localized at the submicronic electrodes tip, and then implementing such structures to address MEMS/NEMS cantilevers local functionalization. Copyright © (2013) by the Chemical and Biological Microsystems Society All rights reserved.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1016/j.snb.2012.11.049

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1002/cphc.201200354

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1088/0960-1317/21/5/054020

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.3390/mi2020258

開催期間： 2021年07月26日 - 2021年07月29日   記述言語：英語   開催地：online  

開催期間： 2019年11月19日 - 2019年11月21日   記述言語：日本語   開催地：静岡県浜松市アクトシティ浜松