Updated on 2022/05/26

写真a

 
SEKIGUCHI, Tetsushi
 
Affiliation
Research Council (Research Organization), Research Organization for Nano & Life Innovation
Job title
Senior Researcher(Professor)

Concurrent Post

  • Faculty of Science and Engineering   School of Fundamental Science and Engineering

Degree

  • 早稲田大学   博士(工学)

Professional Memberships

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    日本麻酔学会

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    日本臨床工学技士会

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    日本生体医工学会

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    電気学会

  •  
     
     

    電気化学協会

  •  
     
     

    応用物理学会

  •  
     
     

    次世代センサ協議会

  •  
     
     

    化学センサ研究会

▼display all

 

Research Areas

  • Nano/micro-systems

  • Measurement engineering

Research Interests

  • chemical sensor

  • medical electronics

  • energy harvesting

  • micro fluidics

Papers

  • Controlling Microdroplet Inner Rotation by Parallel Carrier Flow of Sesame and Silicone Oils

    Hibiki Yoshimura, Daiki Tanaka, Masahiro Furuya, Tetsushi Sekiguchi, Shuichi Shoji

    Micromachines   13 ( 1 ) 9 - 9  2021.12

     View Summary

    We developed a method for passively controlling microdroplet rotation, including interior rotation, using a parallel flow comprising silicone and sesame oils. This device has a simple 2D structure with a straight channel and T-junctions fabricated from polydimethylsiloxane. A microdroplet that forms upstream moves into the sesame oil. Then, the largest flow velocity at the interface of the two oil layers applies a rotational force to the microdroplet. A microdroplet in the lower oil rotates clockwise while that in the upper oil rotates anti-clockwise. The rotational direction was controlled by a simple combination of sesame and silicone oils. Droplet interior flow was visualized by tracking microbeads inside the microdroplets. This study will contribute to the efficient creation of chiral molecules for pharmaceutical and materials development by controlling rotational direction and speed.

    DOI

  • Efficient Generation of Microdroplets Using Tail Breakup Induced with Multi-Branch Channels

    Daiki Tanaka, Satsuki Kajiya, Seito Shijo, Dong Hyun Yoon, Masahiro Furuya, Yoshito Nozaki, Hiroyuki Fujita, Tetsushi Sekiguchi, Shuichi Shoji

    Molecules   26 ( 12 ) 3707 - 3707  2021.06  [Refereed]

     View Summary

    In recent years, research on the application of microdroplets in the fields of biotechnology and chemistry has made remarkable progress, but the technology for the stable generation of single-micrometer-scale microdroplets has not yet been established. In this paper, we developed an efficient and stable single-micrometer-scale droplet generation device based on the fragmentation of droplet tails, called “tail thread mode”, that appears under moderate flow conditions. This method can efficiently encapsulate microbeads that mimic cells and chemical products in passively generated single-micrometer-scale microdroplets. The device has a simple 2D structure; a T-junction is used for droplet generation; and in the downstream, multi-branch channels are designed for droplet deformation into the tail. Several 1–2 µm droplets were successfully produced by the tail’s fragmentation; this continuous splitting was induced by the branch channels. We examined a wide range of experimental conditions and found the optimal flow rate condition can be reduced to one-tenth compared to the conventional tip-streaming method. A mold was fabricated by simple soft lithography, and a polydimethylsiloxane (PDMS) device was fabricated using the mold. Based on the 15 patterns of experimental conditions and the results, the key factors for the generation of microdroplets in this device were examined. In the most efficient condition, 61.1% of the total droplets generated were smaller than 2 μm.

    DOI

  • Validation of droplet-generation performance of a newly developed microfluidic device with a three-dimensional structure

    Yoshito Nozaki, Dong Hyun Yoon, Masahiro Furuya, Hiroyuki Fujita, Tetsushi Sekiguchi, Shuichi Shoji

    Sensors and Actuators A: Physical     112917 - 112917  2021.06  [Refereed]

    DOI

  • Development of Microdroplet Generation Method for Organic Solvents Used in Chemical Synthesis

    Shohei Hattori, Chenghe Tang, Daiki Tanaka, Dong Hyun Yoon, Yoshito Nozaki, Hiroyuki Fujita, Takashiro Akitsu, Tetsushi Sekiguchi, Shuichi Shoji

    Molecules   25 ( 22 ) 5360 - 5360  2020.11  [Refereed]

     View Summary

    Recently, chemical operations with microfluidic devices, especially droplet-based operations, have attracted considerable attention because they can provide an isolated small-volume reaction field. However, analysis of these operations has been limited mostly to aqueous-phase reactions in water droplets due to device material restrictions. In this study, we have successfully demonstrated droplet formation of five common organic solvents frequently used in chemical synthesis by using a simple silicon/glass-based microfluidic device. When an immiscible liquid with surfactant was used as the continuous phase, the organic solvent formed droplets similar to water-in-oil droplets in the device. In contrast to conventional microfluidic devices composed of resins, which are susceptible to swelling in organic solvents, the developed microfluidic device did not undergo swelling owing to the high chemical resistance of the constituent materials. Therefore, the device has potential applications for various chemical reactions involving organic solvents. Furthermore, this droplet generation device enabled control of droplet size by adjusting the liquid flow rate. The droplet generation method proposed in this work will contribute to the study of organic reactions in microdroplets and will be useful for evaluating scaling effects in various chemical reactions.

    DOI

  • Production of vibration energy harvester with impact-sliding structure using magnetostrictive Fe-Co-V alloy rod

    Shin-ichi Yamaura, Takashi Nakajima, Yuki Kamata, Toshio Sasaki, Tetsushi Sekiguchi

    Journal of Magnetism and Magnetic Materials   514   167260 - 167260  2020.11  [Refereed]

    Authorship:Last author

    DOI

  • Microdroplet synthesis of azo compounds with simple microfluidics-based pH control

    Daiki Tanaka, Shunsuke Sawai, Shohei Hattori, Yoshito Nozaki, Dong Hyun Yoon, Hiroyuki Fujita, Tetsushi Sekiguchi, Takashiro Akitsu, Shuichi Shoji

    RSC Advances   10 ( 64 ) 38900 - 38905  2020  [Refereed]

     View Summary

    <p>Conventional solution-phase synthesis of azo compounds is complicated by the need for precise pH and temperature control, high concentrations of pH control reagents, and by-product removal. The microdroplet synthesis method has solved these problems.</p>

    DOI

  • Simple and Rapid Fabrication Process of Porous Silicon Surface Using Inductively Coupled Plasma Reactive Ion Etching

    T. Sugaya, D.H. Yoon, H. Yamazaki, K. Nakanishi, T. Sekiguchi, S. Shoji

    Journal of Microelectromechanical Systems   29 ( 1 ) 62 - 67  2019.11  [Refereed]

  • Integration of Horizontal and Vertical Microfluidic Modules for Core-Shell Droplet Generation and Chemical Application

    Yoon D Nozaki, Y Tanaka, D, Sekiguchi T, Shoji S

    Micromachines   10 ( (9) ) 613 - 624  2019.09  [Refereed]

     View Summary

    This paper presents a method for utilizing three-dimensional microfluidic channels fully to realize multiple functions in a single device. The final device structure was achieved by combining three independent modules that consisted of horizontal and vertical channels. The device allowed for the one-step generation of water-in-oil-in-water droplets without the need for partial treatment of the polydimethylsiloxane channel surface using separate modules for generating water-in-oil droplets on the horizontal plane and oil-in-water droplets on the vertical plane. The second vertically structured module provided an efficient flow for the generation of highly wettable liquid droplets, and tuning of the first horizontally structured module enabled different modes of inner-core encapsulation within the oil shell. The successful integration of the vertical and horizontal channels for core-shell droplet generation and the chemical synthesis of a metal complex within the droplets were evaluated. The proposed approach of integrating independent modules will expand and enhance the functions of microfluidic platforms.

    DOI

  • High-Efficiency Dibromination of Organic Compound in Microfluidic Channel of Si Pillar Array Directly Coated with Iron Catalyst

    T. Sugaya, D. Tanaka, D.H. Yoon, Y. Nozaki, T. Sekiguchi, T. Akitsu, S. Shoji

    The 20th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2019)     2278 - 2281  2019.06  [Refereed]

    DOI

  • Size-Dependent and Property-Independent Passive Microdroplet Sorting by Droplet Transfer on Dot Rails

    D.H. Yoon, D. Tanaka, T. Sekiguchi, S. Shoji

    Micromachines   9 ( 10 )  2018.10  [Refereed]

    DOI

  • Construction of integrated gene logic-chip

    Takeya Masubuchi, Masayuki Endo, Ryo Iizuka, Ayaka Iguchi, Dong Hyun Yoon, Tetsushi Sekiguchi, Hao Qi, Ryosuke Iinuma, Yuya Miyazono, Shuichi Shoji, Takashi Funatsu, Hiroshi Sugiyama, Yoshie Harada, Takuya Ueda, Hisashi Tadakuma

    Nature Nanotechnology   13 ( 10 ) 933 - 940  2018.10  [Refereed]

     View Summary

    © 2018, The Author(s). In synthetic biology, the control of gene expression requires a multistep processing of biological signals. The key steps are sensing the environment, computing information and outputting products1. To achieve such functions, the laborious, combinational networking of enzymes and substrate-genes is required, and to resolve problems, sophisticated design automation tools have been introduced2. However, the complexity of genetic circuits remains low because it is difficult to completely avoid crosstalk between the circuits. Here, we have made an orthogonal self-contained device by integrating an actuator and sensors onto a DNA origami-based nanochip that contains an enzyme, T7 RNA polymerase (RNAP) and multiple target-gene substrates. This gene nanochip orthogonally transcribes its own genes, and the nano-layout ability of DNA origami allows us to rationally design gene expression levels by controlling the intermolecular distances between the enzyme and the target genes. We further integrated reprogrammable logic gates so that the nanochip responds to water-in-oil droplets and computes their small RNA (miRNA) profiles, which demonstrates that the nanochip can function as a gene logic-chip. Our approach to component integration on a nanochip may provide a basis for large-scale, integrated genetic circuits.

    DOI PubMed

  • Structural Formation of Oil-in-Water (O/W) and Water-in-Oil-in-Water (W/O/W) Droplets in PDMS Device Using Protrusion Channel without Hydrophilic Surface Treatment

    D.H. Yoon, D. Tanaka, T. Sekiguchi, S. Shoji

    Micromachines   9 ( 9 ) 468  2018.08  [Refereed]

    DOI

  • Stochastic expression of lactate dehydrogenase A induces Escherichia coli persister formation

    Naoki Yamamoto, Rino Isshiki, Yuto Kawai, Daiki Tanaka, Tetsushi Sekiguchi, Shinya Matsumoto, Satoshi Tsuneda

    Journal of Bioscience and Bioengineering   126 ( 1 ) 30 - 37  2018.07  [Refereed]

     View Summary

    Bacterial persisters are phenotypic variants that survive the treatment of lethal doses of growth-targeting antibiotics without mutations. Although the mechanism underlying persister formation has been studied for decades, how the persister phenotype is switched on and protects itself from antibiotics has been elusive. In this study, we focused on the lactate dehydrogenase gene (ldhA) that was upregulated in an Escherichia coli persister-enriched population. A survival rate assay using an ldhA-overexpressing strain showed that ldhA expression induced persister formation. To identify ldhA-mediated persister formation at the single-cell level, time-lapse microscopy with a microfluidic device was used. Stochastic ldhA expression was found to induce dormancy and tolerance against high-dose ampicillin treatment (500 μg/ml). To better understand the underlying mechanism, we investigated the relationship between ldhA-mediated persister formation and previously reported persister formation through aerobic metabolism repression. As a result, ldhA expression enhanced the proton motive force (PMF) and ATP synthesis. These findings suggest that ldhA-mediated persister formation pathway is different from previously reported persister formation via repression of aerobic metabolism.

    DOI

  • Mechanical Reinforcement of Low-Concentration Alginate Fibers by Microfluidic Embedding of Multiple Cores

    Dong Hyun Yoon, Daiki Tanaka, Tetsushi Sekiguchi, Shuichi Shoji

    Macromolecular Materials and Engineering   303 ( 3 ) 1700516 - 1700521  2018.03  [Refereed]

     View Summary

    This paper presents mechanically reinforced low-concentration alginate fibers by embedding inner cores of high-concentration alginate. 3D structures by stacking multiple polydimethylsiloxane (PDMS) layers allow the microfluidic formation and control of the isolated cores in the continuous flow. The alginate hydrogel fibers are simply spun, and the compartments, central core, surrounding cores, and outer shell layer are successfully verified. The results demonstrate the great potential for the development of complex fibrous materials, particularly for biological applications, which require specific morphology and composition of the fibers.

    DOI

  • Analysis of vinylidene fluoride-trifluoroethylene copolymer film for nonpolarized energy harvester

    Yuki Kamata, Tetsushi Sekiguchi, Takashi Nakajima, Toshio Sasaki, Yoon Dong-Hyun, Daiki Tanaka, Shuichi Shoji

    JAPANESE JOURNAL OF APPLIED PHYSICS   56 ( 7 ) 070301-1 - 070301-3  2017.07  [Refereed]

     View Summary

    In this paper, an investigation of a vinylidene fluoride-trifluoroethylene (VDF/TrFE) copolymer film for use in a nonpolarized energy harvester is presented. The Fourier transform infrared spectroscopy and X-ray diffraction analysis of a nonpolarized VDF/TrFE copolymer film indicate that polymer crystallinity depends on film thickness. Furthermore, the growth of the polar structure (beta phase) is observed upon the reduction in the thickness. However, power generation does not exhibit a linear behavior because the generation capacity increases with the thickness. These results indicate that the film thickness for a nonpolarized harvester must be optimized to obtain the maximum output. (C) 2017 The Japan Society of Applied Physics

    DOI

  • Simple microfluidic formation of highly heterogeneous microfibers using a combination of sheath units

    D. H. Yoon, K. Kobayashi, D. Tanaka, T. Sekiguchi, S. Shoji

    LAB ON A CHIP   17 ( 8 ) 1481 - 1486  2017.04  [Refereed]

     View Summary

    This paper presents the formation of complex cross-sectional microfibers using three-dimensional microfluidic devices. The compartments and shapes of core and shell layers in the microfibers were independently controlled via three-dimensional fluidic channels fabricated by the combination of sheath units. The number of layers is easily expanded by the stacking of these units. Therefore, the highly heterogeneous microfibers of alginate hydrogel are obtained in polydimethylsiloxane structures. This widely expandable method has great potential for the development of functional and complex fiber-shaped materials.

    DOI

  • Simple microfluidic formation of highly heterogeneous microfibers using a combination of sheath units

    D. H. Yoon, K. Kobayashi, D. Tanaka, T. Sekiguchi, S. Shoji

    LAB ON A CHIP   17 ( 8 ) 1481 - 1486  2017.04  [Refereed]

     View Summary

    This paper presents the formation of complex cross-sectional microfibers using three-dimensional microfluidic devices. The compartments and shapes of core and shell layers in the microfibers were independently controlled via three-dimensional fluidic channels fabricated by the combination of sheath units. The number of layers is easily expanded by the stacking of these units. Therefore, the highly heterogeneous microfibers of alginate hydrogel are obtained in polydimethylsiloxane structures. This widely expandable method has great potential for the development of functional and complex fiber-shaped materials.

    DOI

  • Development of an ex vivo brain lactic acid monitoring system

    Shuya Negishi, Shoto Kamada, Riichi Kajiwara, Yuji Kaneko, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji, Hiroyuki Kudo

    IEEJ Transactions on Sensors and Micromachines   137 ( 1 ) 38 - 43  2017  [Refereed]

     View Summary

    An ex vivo brain lactic acid (LA) monitoring system for investigating brain activity at the organ level was constructed and tested in continuous LA monitoring. Our system consists of a micro-fluidic dual-analyte (LA and glucose) biosensor and a special brain chamber that is suitable for organ level experiments. The biosensor utilizes the redox reactions of osmium-wired horseradish peroxidase (Os-HRP) to detect hydrogen peroxide produced by enzyme reactions. The sensor had sufficient sensitivity (LA: ∼ 0.01 mM, glucose: ∼ 0.01 mM) and selectivity for assessment of extracellular LA. The ex vivo monitoring of brain LA was performed using the proposed system. As a result, the change in extracellular LA was successfully monitored continuously, and the change in the LA level was considered the result of metabolic activity of the sample. Our system is expected to be useful not only for ex vivo brain monitoring, but also for monitoring other organs.

    DOI

  • Development of low-cost mass production process of superrepellent surface using doubly reentrant structure pillar array

    Kanki Nakanishi, Shigeyuki Minoshiro, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji

    IEEJ Transactions on Sensors and Micromachines   137 ( 6 ) 165 - 168  2017  [Refereed]

     View Summary

    A new fabrication process of a superrepellent surface using a doubly reentrant structure pillar array was developed. The proposed process applying a soft-lithography is simple, low-cost, and mass-productive process compared to the conventional process. It enables to fabricate a doubly reentrant structure pillar array on glass, silicon, and PDMS substrates.

    DOI CiNii

  • A high-resolution passive droplet-phase sample sorter using multi-stage droplet transfer

    D. H. Yoon, Z. Xie, D. Tanaka, T. Sekiguchi, S. Shoji

    RSC ADVANCES   7 ( 58 ) 36750 - 36754  2017  [Refereed]

     View Summary

    A fully passive volume-dependent droplet sorter is presented in this research. Repeated and multiple on-rail transfer of microdroplets in a cascade channel resulted in high resolution sorting of droplet-phase samples. Microdroplets with volumes of 0.89-3.26 nl were successfully sorted in eight steps, and a maximum sorting resolution of about 0.21 nl was obtained over three transfer stages. Line rails and dot rails employed in the cascading channels allowed volume-dependent droplet transfer, and shape recovery of the transferred droplet for the repeatable transfer, respectively. This simple device and method can be applied to droplet-based chemical or biological research.

    DOI

  • Synthesis of an azo-Mn(II) complex with mild pH control using a microfluidic device

    Daiki Tanaka, Shunsuke Sawai, Dong Hyun Yoon, Tetsushi Sekiguchi, Takashiro Akitsu, Shuichi Shoji

    RSC ADVANCES   7 ( 63 ) 39576 - 39582  2017  [Refereed]

     View Summary

    This study describes the synthesis of an azo-Mn(II) complex requiring an accurate pH control. The reaction conditions for the delicate azo-Mn(II) complex could be precisely controlled using a microfluidic device. The microfluidic method showed the following advantages over the conventional method: the concentration of the pH-control reagent was reduced (1/15), the reaction time was remarkably decreased from 4 h to less than 1 s, and the reaction temperature was lowered from 40 to 23 degrees C. Moreover, the microfluidic device suppressed the oxidation of the compound and did not require cooling to remove the heat of reaction. In addition, the conventional method uses harsh pH control, whereas the microfluidic device permits mild pH control.

    DOI

  • Stacked piezoelectric energy harvesting device by printing process

    Yuki Kamata, Dong Hyun Yoon, Toshio Sasaki, Yoshito Nozaki, Shinichi Yamaura, Tetsushi Sekiguchi, Takashi Nakajima, Shuichi Shoji

    MICRO & NANO LETTERS   11 ( 10 ) 650 - 653  2016.10  [Refereed]

     View Summary

    A simple printing process to design a novel piezoelectric energy-harvesting device made from vinylidene fluoride/trifluoroethylene copolymers is presented. Fabrication using a metal nanoink and a household printer dramatically reduced the fabrication complexity. In addition, this process employed low-temperature steps, and thus the structural damage to the polymers resulting from high-temperature annealing was avoided. By stacking the devices and connecting them in parallel, the generated energy was increased and electric power of approximate to 1.12 J was obtained.

    DOI

  • Rapid quantitative method for the detection of phenylalanine and tyrosine in human plasma using pillar array columns and gradient elution

    Yanting Song, Katsuya Takatsuki, Tetsushi Sekiguchi, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    AMINO ACIDS   48 ( 7 ) 1731 - 1735  2016.07  [Refereed]

     View Summary

    This study reports a fast and quantitative determination method for phenylalanine (Phe) and tyrosine (Tyr) in human plasma using on-chip pressure-driven liquid chromatography. A pillar array column with low-dispersion turns and a gradient elution system was used. The separation of fluorescent derivatives of Phe, Tyr, and other hydrophobic amino acids was successfully performed within 140 s. Under the optimized conditions, Phe and Tyr in human plasma were quantified. The developed method is promising for rapid diagnosis in the clinical field.

    DOI

  • 3D Structures: Microfluidic Stamping on Sheath Flow (Small 24/2016)

    Dong Hyun Yoon, Daiki Tanaka, Tetsushi Sekiguchi, Shuichi Shoji

    Small     3200  2016.06

    DOI PubMed

  • 3D Structures: Microfluidic Stamping on Sheath Flow (Small 24/2016)

    Dong Hyun Yoon, Daiki Tanaka, Tetsushi Sekiguchi, Shuichi Shoji

    Small   ( 24 ) 3200 - 5  2016.06  [Refereed]

     View Summary

    A microfluidic stamping method to form functional shapes on a cross section in fibre-shaped flow is presented by D. H. Yoon and co-workers on page 3224. Microfluidic stamping and overstamping allowed various cross sectional shapes on the three-dimensional flow. Dimension of the flows is controlled via a change in combination of 3D structures and fluidic conditions, which correspond to stamp type and stamping force.

    DOI PubMed

  • Liquid Chromatography Chip with Low-Dispersion and Low-Pressure-Drop Turn Structure Utilizing a Distribution-Controlled Pillar Array

    Muneld Isokawa, Katsuya Takatsuki, Yanting Song, Kailing Shih, Kanki Nakanishi, Zhimin Xie, Dong Hyun Yoon, Tetsushi Sekiguchi, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    ANALYTICAL CHEMISTRY   88 ( 12 ) 6485 - 6491  2016.06  [Refereed]

     View Summary

    To realize efficient, fast separations on pillar array columns with turns, a novel turn with low-dispersion and low-pressure-drop properties was developed. This "pillar-distribution controlled" (PDC) turn was designed as a constant-radius-turn filled with octagonal pillars that were arranged to control the linear velocity of the mobile phase in the radial direction. After the pillar positions were adjusted by computational fluid dynamics analysis, 27 mm long pillar array columns with two turns were fabricated on a 20 x 20 mm(2) silicon glass plate. The PDC turns suppressed the sample dispersion to a similar extent as the previously developed tapered turn, and the pressure drop of the newly designed turn was reduced to similar to 1/6 that of the tapered turn. Moreover, the C18-modified pillar array column with the PDC turns showed good bioanalytical applicability; five fluorescendy labeled amino acids were separated in only 24 s at a linear velocity of 7.5 mm/s. The developed turn structure offers the advantages of longer pillar array columns with more turns for the fast analysis of complex samples.

    DOI

  • Liquid Chromatography Chip with Low-Dispersion and Low-Pressure-Drop Turn Structure Utilizing a Distribution-Controlled Pillar Array

    Muneld Isokawa, Katsuya Takatsuki, Yanting Song, Kailing Shih, Kanki Nakanishi, Zhimin Xie, Dong Hyun Yoon, Tetsushi Sekiguchi, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    ANALYTICAL CHEMISTRY   88 ( 12 ) 6485 - 6491  2016.06  [Refereed]

     View Summary

    To realize efficient, fast separations on pillar array columns with turns, a novel turn with low-dispersion and low-pressure-drop properties was developed. This "pillar-distribution controlled" (PDC) turn was designed as a constant-radius-turn filled with octagonal pillars that were arranged to control the linear velocity of the mobile phase in the radial direction. After the pillar positions were adjusted by computational fluid dynamics analysis, 27 mm long pillar array columns with two turns were fabricated on a 20 x 20 mm(2) silicon glass plate. The PDC turns suppressed the sample dispersion to a similar extent as the previously developed tapered turn, and the pressure drop of the newly designed turn was reduced to similar to 1/6 that of the tapered turn. Moreover, the C18-modified pillar array column with the PDC turns showed good bioanalytical applicability; five fluorescendy labeled amino acids were separated in only 24 s at a linear velocity of 7.5 mm/s. The developed turn structure offers the advantages of longer pillar array columns with more turns for the fast analysis of complex samples.

    DOI

  • Microfluidic Stamping on Sheath Flow

    Dong Hyun Yoon, Daiki Tanaka, Tetsushi Sekiguchi, Shuichi Shoji

    SMALL   12 ( 24 ) 3224 - 3228  2016.06  [Refereed]

     View Summary

    A microfluidic stamping method to form functional shapes on a cross section in fiber-shaped flow is proposed. Microfluidic stamping and overstamping allow various cross sectional shapes on the 3D flow. The shapes can be controlled by a change in combination of structures and fluidic conditions which correspond to stamp type and stamping force.

    DOI PubMed

  • Culture-independent method for identification of microbial enzyme-encoding genes by activity-based single-cell sequencing using a water-in-oil microdroplet platform

    Kazuki Nakamura, Ryo Iizuka, Shinro Nishi, Takao Yoshida, Yuji Hatada, Yoshihiro Takaki, Ayaka Iguchi, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji, Takashi Funatsu

    SCIENTIFIC REPORTS   6 ( 6 ) 22259  2016.02  [Refereed]

     View Summary

    Environmental microbes are a great source of industrially valuable enzymes with potent and unique catalytic activities. Unfortunately, the majority of microbes remain unculturable and thus are not accessible by culture-based methods. Recently, culture-independent metagenomic approaches have been successfully applied, opening access to untapped genetic resources. Here we present a methodological approach for the identification of genes that encode metabolically active enzymes in environmental microbes in a culture-independent manner. Our method is based on activity-based single-cell sequencing, which focuses on microbial cells showing specific enzymatic activities. First, at the single-cell level, environmental microbes were encapsulated in water-in-oil microdroplets with a fluorogenic substrate for the target enzyme to screen for microdroplets that contain microbially active cells. Second, the microbial cells were recovered and subjected to whole genome amplification. Finally, the amplified genomes were sequenced to identify the genes encoding target enzymes. Employing this method, we successfully identified 14 novel beta-glucosidase genes from uncultured bacterial cells in marine samples. Our method contributes to the screening and identification of genes encoding industrially valuable enzymes.

    DOI

  • Culture-independent method for identification of microbial enzyme-encoding genes by activity-based single-cell sequencing using a water-in-oil microdroplet platform

    Kazuki Nakamura, Ryo Iizuka, Shinro Nishi, Takao Yoshida, Yuji Hatada, Yoshihiro Takaki, Ayaka Iguchi, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji, Takashi Funatsu

    SCIENTIFIC REPORTS   6 ( 6 ) 22259  2016.02  [Refereed]

     View Summary

    Environmental microbes are a great source of industrially valuable enzymes with potent and unique catalytic activities. Unfortunately, the majority of microbes remain unculturable and thus are not accessible by culture-based methods. Recently, culture-independent metagenomic approaches have been successfully applied, opening access to untapped genetic resources. Here we present a methodological approach for the identification of genes that encode metabolically active enzymes in environmental microbes in a culture-independent manner. Our method is based on activity-based single-cell sequencing, which focuses on microbial cells showing specific enzymatic activities. First, at the single-cell level, environmental microbes were encapsulated in water-in-oil microdroplets with a fluorogenic substrate for the target enzyme to screen for microdroplets that contain microbially active cells. Second, the microbial cells were recovered and subjected to whole genome amplification. Finally, the amplified genomes were sequenced to identify the genes encoding target enzymes. Employing this method, we successfully identified 14 novel beta-glucosidase genes from uncultured bacterial cells in marine samples. Our method contributes to the screening and identification of genes encoding industrially valuable enzymes.

    DOI

  • Retention and Bandwidth Predictions by Fast Gradient Elution Chromatography Using a Pillar Array Column

    Yanting Song, Katsuya Takatsuki, Tetsushi Sekiguchi, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    CHROMATOGRAPHY   37 ( 3 ) 111 - 116  2016

     View Summary

    Previously, we have developed a gradient elution system for pillar array columns, which achieved faster separation than isocratic elution. In this study, we validated gradient elution in microchip liquid chromatography (LC) and investigated the retention and bandwidth predictions of fluorescently labeled aliphatic amines in fast gradient elution chromatography using semi-empirical retention models. The retention times and peak widths under different gradient elution programs were predicted by three solvent strength models and compared with the experimental results. The relative errors of prediction for the retention times and peak widths were below 14 % and 12 %, respectively. The results showed that the solvent strength models could be utilized for predicting the retention times and peak widths under gradient elution in the microchip LC system and that the gradient elution program for pillar array columns worked efficiently. The prediction by the retention model promises to be a potential tool for essential compound identification in biological samples.

    DOI CiNii

  • Microfluidic synthesis of chiral salen Mn(II) and Co(II) complexes containing lysozyme

    Daiki Tanaka, Wataru Kawakubo, Erika Tsuda, Yuya Mitsumoto, Dong Hyun Yoon, Tetsushi Sekiguchi, Takashiro Akitsu, Shuichi Shoji

    RSC ADVANCES   6 ( 85 ) 81862 - 81868  2016  [Refereed]

     View Summary

    Efficient microfluidic synthesis of chiral salen Mn(II) and Co(II) complexes containing lysozyme was achieved. The reaction conditions for the delicate protein were controlled precisely with a separation barrier in the microfluidic device. The microfluidic method has the following advantages over the conventional method: a remarkable reduction in the reaction time from 4.5 h to less than 1 s for the synthesis of Mn(II) and Co(II) complexes, a reduction in the reaction temperature from 40 to 23 degrees C, and no need for an N-2 atmosphere because all the reagents are isolated from the air. A three-fold yield improvement was achieved for Mn(II) and Co(II) complexes containing lysozyme compared with conventional synthesis.

    DOI

  • ALL-ROUND MICRO SHEATH FLOW FORMATION TO REALIZE COMPLEX CROSS SECTIONS BY SIMPLY STACKED PDMS STRUCTURES

    Dong Hyun Yoon, Lisa Ariyoshi, Daiki Tanaka, Tetsushi Sekiguchi, Shuichi Shoji

    2016 IEEE 29TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS)   2016-February   141 - 144  2016  [Refereed]

     View Summary

    This research proposed a sheath flow formation method for complex 3D structure such as multi-core and multi-sheath using multi-stacked PDMS units. Cross sectional shape of the flow and the number of sheath layer were defined simply by combination of different PDMS units. The stacked PDMS units allowed independent fluid injection of different layers and the short sheath area realized low diffusion between each layer. Furthermore, the proposed 3D device fabrication method requires only one point alignment. The sheath flow formation method is useful for wide applications which require fiber materials of specific cross sectional shapes and layers.

    DOI

  • Microfluidic synthesis of chiral salen Mn(II) and Co(II) complexes containing lysozyme

    Daiki Tanaka, Wataru Kawakubo, Erika Tsuda, Yuya Mitsumoto, Dong Hyun Yoon, Tetsushi Sekiguchi, Takashiro Akitsu, Shuichi Shoji

    RSC ADVANCES   6 ( 85 ) 81862 - 81868  2016  [Refereed]

     View Summary

    Efficient microfluidic synthesis of chiral salen Mn(II) and Co(II) complexes containing lysozyme was achieved. The reaction conditions for the delicate protein were controlled precisely with a separation barrier in the microfluidic device. The microfluidic method has the following advantages over the conventional method: a remarkable reduction in the reaction time from 4.5 h to less than 1 s for the synthesis of Mn(II) and Co(II) complexes, a reduction in the reaction temperature from 40 to 23 degrees C, and no need for an N-2 atmosphere because all the reagents are isolated from the air. A three-fold yield improvement was achieved for Mn(II) and Co(II) complexes containing lysozyme compared with conventional synthesis.

    DOI

  • Retention and Bandwidth Predictions by Fast Gradient Elution Chromatography Using a Pillar Array Column

    Yanting Song, Katsuya Takatsuki, Tetsushi Sekiguchi, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    CHROMATOGRAPHY   37 ( 3 ) 111 - 116  2016  [Refereed]

     View Summary

    Previously, we have developed a gradient elution system for pillar array columns, which achieved faster separation than isocratic elution. In this study, we validated gradient elution in microchip liquid chromatography (LC) and investigated the retention and bandwidth predictions of fluorescently labeled aliphatic amines in fast gradient elution chromatography using semi-empirical retention models. The retention times and peak widths under different gradient elution programs were predicted by three solvent strength models and compared with the experimental results. The relative errors of prediction for the retention times and peak widths were below 14 % and 12 %, respectively. The results showed that the solvent strength models could be utilized for predicting the retention times and peak widths under gradient elution in the microchip LC system and that the gradient elution program for pillar array columns worked efficiently. The prediction by the retention model promises to be a potential tool for essential compound identification in biological samples.

    DOI CiNii

  • Development of a Simple Fabrication Process for a Printable Piezoelectric Energy Harvest Device

    Yuki Kamata, Donghyun Yoon, Toshio Sasaki, Yoshito Nozaki, Shinichi Yamaura, Tetsushi Sekiguchi, Takashi Nakajima, Syuichi Shoji

    2016 IEEE 11TH ANNUAL INTERNATIONAL CONFERENCE ON NANO/MICRO ENGINEERED AND MOLECULAR SYSTEMS (NEMS)     520 - 523  2016  [Refereed]

     View Summary

    This paper presents a simple printing process to design a novel piezoelectric energy harvest device made from (VDF/TrFE) copolymers. The fabrication process using metal nano-ink and a household printer dramatically reduced the fabrication complexity. Additionally, this process employed low temperatures and thus the structural damage of the polymers resulting from high temperature annealing could be avoided. An electric power of about 0.06 mu J was generated using this device.

    DOI

  • Fabrication Process of Fluidic Devices for Producing Fine Droplets Using a Focused Ion Beam System

    Y. Nozaki, T. Kanai, A. Matsuo, D. Tanaka, I. Yuito, T. Takeuchi, T. Sekiguchi, S. Shoji

    2016 IEEE 16TH INTERNATIONAL CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO)     795 - 798  2016  [Refereed]

     View Summary

    We conducted an experiment on the fabrication of fluidic devices for producing fine droplets. In our proposed method, multiple channels were fabricated by using a focused ion beam (FIB) system. The minimum feature top width was found to be approximately 56 nm. When both the target width and depth of one channel were set to 500 nm, the resultant top width was 750-780 nm, the bottom width was 250-320 nm, and the depth was 560 nm, almost achieving the target size for the channel depth.

    DOI

  • Droplet-based microfluidics for high-throughput screening of a metagenomic library for isolation of microbial enzymes

    Masahito Hosokawa, Yuri Hoshino, Yohei Nishikawa, Tomotada Hirose, Dong Hyun Yoon, Tetsushi Mori, Tetsushi Sekiguchi, Shuichi Shoji, Haruko Takeyama

    BIOSENSORS & BIOELECTRONICS   67   379 - 385  2015.05  [Refereed]

     View Summary

    This paper proposes a high-throughput, function-based screening approach of a metagenomic library for isolating novel microbial enzymes by droplet-based microfluidics. We used gel microdroplets (GMDs) dispersed in oil as picoliter-volume reaction vessels for lipolytic enzyme by encapsulating cells in individual GMDs. Using this approach, we monitored the growth of individual cells encapsulated in GMDs and assessed the enzyme reaction activities at the level of an individual GMD. We then applied this method to screen lipolytic enzyme genes from the metagenomic library constructed from soil collected from a quercus serrate forest of Mount Tsukuba, Ibaraki, Japan. In the workflow presented in this study, metagenomic library clones were encapsulated in 100-pL GMDs with a fluorogenic reporter substrate. A total of 67,000 metagenomic library clones can be screened in only 24 h with reduced consumption of reagents (i.e., &lt; 10 mu L). As a result, we identified a novel lipolytic enzyme, EstT1, belonging to the EstD2 family of esterases and containing a putative signal peptide, which facilitates enzyme export and catalyzation of substrates in the periplasm. Our study demonstrates the potential of microfluidic GMDs as an efficient tool for metagenomic library screening of industrially relevant enzymes with the potential of significantly reducing the cost and time factors involved in successful practical application of microbial enzymes. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • Formation of Polymeric Hollow Microcapsules and Microlenses Using Gas-in-Organic-in-Water Droplets

    Dong Hyun Yoon, Kenta Hasegawa, Yuji Kaneko, Takahiro Arakawa, Jeung Sang Go, Tetsushi Sekiguchi, Shuichi Shoji

    MICROMACHINES   6 ( 5 ) 622 - 633  2015.05  [Refereed]

     View Summary

    This paper presents methods for the formation of hollow microcapsules and microlenses using multiphase microdroplets. Microdroplets, which consist of a gas core and an organic phase shell, were generated at a single junction on a silicon device without surface treatment of the fluidic channels. Droplet, core and shell dimensions were controlled by varying the flow rates of each phase. When the organic solvent was released from the organic phase shell, the environmental conditions changed the shape of the solidified polymer shell to either a hollow capsule or a microlens. A uniform solvent release process produced polymeric capsules with nanoliter gas core volumes and a membrane thickness of approximately 3 mu m. Alternatively physical rearrangement of the core and shell allowed for the formation of polymeric microlenses. On-demand formation of the polymer lenses in wells and through-holes polydimethylsiloxane (PDMS) structures was achieved. Optical properties of the lenses were controlled by changing the dimension of these structures.

    DOI

  • Droplet-based microfluidics for high-throughput screening of a metagenomic library for isolation of microbial enzymes

    Masahito Hosokawa, Yuri Hoshino, Yohei Nishikawa, Tomotada Hirose, Dong Hyun Yoon, Tetsushi Mori, Tetsushi Sekiguchi, Shuichi Shoji, Haruko Takeyama

    BIOSENSORS & BIOELECTRONICS   67   379 - 385  2015.05  [Refereed]

     View Summary

    This paper proposes a high-throughput, function-based screening approach of a metagenomic library for isolating novel microbial enzymes by droplet-based microfluidics. We used gel microdroplets (GMDs) dispersed in oil as picoliter-volume reaction vessels for lipolytic enzyme by encapsulating cells in individual GMDs. Using this approach, we monitored the growth of individual cells encapsulated in GMDs and assessed the enzyme reaction activities at the level of an individual GMD. We then applied this method to screen lipolytic enzyme genes from the metagenomic library constructed from soil collected from a quercus serrate forest of Mount Tsukuba, Ibaraki, Japan. In the workflow presented in this study, metagenomic library clones were encapsulated in 100-pL GMDs with a fluorogenic reporter substrate. A total of 67,000 metagenomic library clones can be screened in only 24 h with reduced consumption of reagents (i.e., &lt; 10 mu L). As a result, we identified a novel lipolytic enzyme, EstT1, belonging to the EstD2 family of esterases and containing a putative signal peptide, which facilitates enzyme export and catalyzation of substrates in the periplasm. Our study demonstrates the potential of microfluidic GMDs as an efficient tool for metagenomic library screening of industrially relevant enzymes with the potential of significantly reducing the cost and time factors involved in successful practical application of microbial enzymes. (C) 2014 Elsevier B.V. All rights reserved.

    DOI PubMed

  • Formation of Polymeric Hollow Microcapsules and Microlenses Using Gas-in-Organic-in-Water Droplets

    Dong Hyun Yoon, Kenta Hasegawa, Yuji Kaneko, Takahiro Arakawa, Jeung Sang Go, Tetsushi Sekiguchi, Shuichi Shoji

    MICROMACHINES   6 ( 5 ) 622 - 633  2015.05  [Refereed]

     View Summary

    This paper presents methods for the formation of hollow microcapsules and microlenses using multiphase microdroplets. Microdroplets, which consist of a gas core and an organic phase shell, were generated at a single junction on a silicon device without surface treatment of the fluidic channels. Droplet, core and shell dimensions were controlled by varying the flow rates of each phase. When the organic solvent was released from the organic phase shell, the environmental conditions changed the shape of the solidified polymer shell to either a hollow capsule or a microlens. A uniform solvent release process produced polymeric capsules with nanoliter gas core volumes and a membrane thickness of approximately 3 mu m. Alternatively physical rearrangement of the core and shell allowed for the formation of polymeric microlenses. On-demand formation of the polymer lenses in wells and through-holes polydimethylsiloxane (PDMS) structures was achieved. Optical properties of the lenses were controlled by changing the dimension of these structures.

    DOI

  • Chemical Reaction in Microdroplets with Different Sizes Containing CdSe/ZnS Quantum Dot and Organic Dye

    Takeshi Fukuda, Tomokazu Kurabayashi, Hikari Udaka, Nayuta Funaki, Miho Suzuki, Donghyun Yoon, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    IEICE TRANSACTIONS ON ELECTRONICS   E98C ( 2 ) 123 - 126  2015.02  [Refereed]

     View Summary

    We report a real time method to monitor the chemical reaction in microdroplets, which contain an organic dye, 5(6)-carboxynaphthofluorescein and a CdSe/ZnS quantum dot using fluorescence spectra. Especially, the relationship between the droplet size and the reaction rate of the two reagents was investigated by changing an injection speed.

    DOI

  • Chemical reaction in microdroplets with different sizes containing CdSe/ZnS quantum dot and organic dye

    Takeshi Fukuda, Tomokazu Kurabayashi, Hikari Udaka, Nayuta Funaki, Miho Suzuki, Donghyun Yoon, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    IEICE Transactions on Electronics   E98C ( 2 ) 123 - 126  2015.02  [Refereed]

     View Summary

    We report a real time method to monitor the chemical reaction in microdroplets, which contain an organic dye, 5(6)-carboxynaphthofluorescein and a CdSe/ZnS quantum dot using fluorescence spectra. Especially, the relationship between the droplet size and the reaction rate of the two reagents was investigated by changing an injection speed.

    DOI CiNii

  • Chemical reaction in microdroplets with different sizes containing CdSe/ZnS quantum dot and organic dye

    Takeshi Fukuda, Tomokazu Kurabayashi, Hikari Udaka, Nayuta Funaki, Miho Suzuki, Donghyun Yoon, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    IEICE Transactions on Electronics   E98C ( 2 ) 123 - 126  2015.02  [Refereed]

     View Summary

    We report a real time method to monitor the chemical reaction in microdroplets, which contain an organic dye, 5(6)-carboxynaphthofluorescein and a CdSe/ZnS quantum dot using fluorescence spectra. Especially, the relationship between the droplet size and the reaction rate of the two reagents was investigated by changing an injection speed.

    DOI

  • Selective droplet sampling using a minimum number of horizontal pneumatic actuators in a high aspect ratio and highly flexible PDMS device

    Dong Hyun Yoon, Daisuke Wakui, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    RSC ADVANCES   5 ( 3 ) 2070 - 2074  2015  [Refereed]

     View Summary

    This paper presents a droplet sampling device driven by horizontal pneumatic actuators. A high aspect ratio and highly flexible PDMS (polydimethylsiloxane) structure was proposed for carrying out larger number of sampling than the number of actuators. Large deformation of the actuators caused domino-deformation of parallel walls, and the deformations allowed for selective collection of target droplets. The dimensions of the PDMS structure and the ratio of resin to curing agent were optimized for efficient sampling under the low pressure applied to the actuators. Five sampling modes were achieved in the simple one-layer structure consisting of one inlet, four walls, one drain channel, and two pneumatic actuators, formed by single-step soft lithography process.

    DOI

  • Research Progress on Materials for Environmental Protection and Advanced Energy of Enviroment and Energy Materials Development Group

    Yamaura Shin-ichi, Sekiguchi Tetsushi, Yogo Toshinobu

    Bulletin of the Japan Institute of Metals   54 ( 5 ) 227 - 231  2015

    CiNii

  • ONE CORE-FIVE SHEATHS COAXIAL FLOW FORMATION USING MULTILAYER STACKED FLOW FOCUSING STRUCTURE

    D. H. Yoon, J. Ito, N. Takeda, T. Sekiguchi, S. Shoji

    2015 28TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2015)     539 - 542  2015  [Refereed]

     View Summary

    This research presents efficient coaxial sheath flow formation using a three-dimensional PDMS device. In the device, one core and five sheaths are simply formed with low diffusion between different samples. Stacking and alignment of six PDMS layers of same structure allowed for fabrication of the proposed 3D device. Only one point alignment of center channel for the sheath provides free from misalignment that was a critical problem of multi-stacked PDMS device. Furthermore, the number of samples is infinitely expandable by increase in the number of stacking layers. The coaxial sheath flow is useful for biological fiber formation which requires multilayer of different materials such as artificial blood vessels or muscles.

    DOI

  • HIGHLY CONTROLLABLE THREE-DIMENSIONAL SHEATH FLOW DEVICE FOR FABRICATION OF ARTIFICIAL CAPILLARY VESSELS

    J. Ito, R. Sekine, D. H. Yoon, Y. Nakamura, H. Oku, H. Nansai, T. Chikasawa, T. Goto, T. Sekiguchi, N. Takeda, S. Shoji

    2015 28TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2015)     480 - 483  2015  [Refereed]

     View Summary

    This paper reports a highly controllable three-dimensional (3D) sheath flow device for fabrication of artificial capillary vessels. Three step sheath injection type 3D flow device which realizes wide core and sheath structure variations by simply flow rate control was applied to fabricate double-layer coaxial Core-Sheath microfibers applicable for long micro capillary vessels by aligning and cultivating vascular endothelial cells. As a result, about a 3-centimeter-long microfiber which has the vascular endothelial cells fused mutually in the center was successfully formed after three days culture.

    DOI

  • Selective droplet sampling using a minimum number of horizontal pneumatic actuators in a high aspect ratio and highly flexible PDMS device

    Dong Hyun Yoon, Daisuke Wakui, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    RSC ADVANCES   5 ( 3 ) 2070 - 2074  2015  [Refereed]

     View Summary

    This paper presents a droplet sampling device driven by horizontal pneumatic actuators. A high aspect ratio and highly flexible PDMS (polydimethylsiloxane) structure was proposed for carrying out larger number of sampling than the number of actuators. Large deformation of the actuators caused domino-deformation of parallel walls, and the deformations allowed for selective collection of target droplets. The dimensions of the PDMS structure and the ratio of resin to curing agent were optimized for efficient sampling under the low pressure applied to the actuators. Five sampling modes were achieved in the simple one-layer structure consisting of one inlet, four walls, one drain channel, and two pneumatic actuators, formed by single-step soft lithography process.

    DOI

  • HIGH EFFICIENT SYNTHESIS OF MANGANESE(II), COBALT(II) COMPLEXES CONTAINING LYSOZYME USING REACTION AREA SEPARATED MICRO FLUIDIC DEVICE

    D. Tanaka, Y. Murakoshi, E. Tsuda, Y. Mitsumoto, D. H. Yoon, T. Sekiguchi, T. Akitsu, S. Shoji

    2015 TRANSDUCERS - 2015 18TH INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS (TRANSDUCERS)     243 - 246  2015  [Refereed]

     View Summary

    High-efficient synthesis of Mn(II) and Co(II) complexes containing lysozyme using a reaction area-separated-type microfluidic device was realized.
    The proposed method has the following advantages compared to the conventional method: reduction of reaction temperature from 40 degrees C to 23 degrees C; remarkable reduction of reaction time from 4 hours to less than 1 second for synthesis of Mn(II) and Co(II) complexes; and atmosphere control (in N-2) of the previous steps is not required because all reagents are isolated from the air.
    A three-fold yield improvement was achieved in the synthesis of metal complexes containing lysozyme.

    DOI

  • Depth Profiles of Absorbed Hydrogen in Ni-Nb-Zr Amorphous Alloy Ribbons by Glow Discharge Optical Emission Spectroscopy

    R. Y. Umetsu, M. Saito, T. Sasaki, T. Sekiguchi, J. Mizuno, H. Kawarada

    Open Journal of Metal   4 ( 4 ) 112 - 119  2014.12  [Refereed]

    DOI

  • Basic Research of Vibration Energy Harvesting Micro Device using Vinylidene Fluoride / Trifluoroethylene Copolymer Thin Film

    T. Takiguchi, T. Sasaki, T. Nakajima, S. Yamaura, T. Sekiguchi, S. Shoji

    Journal of Physics: Conference Series   557   012030  2014.11  [Refereed]

    DOI

  • Real-time monitoring of chemical reaction in microdroplet using fluorescence spectroscopy

    Takeshi Fukuda, Nayuta Funaki, Tomokazu Kurabayashi, Miho Suzuki, Dong Hyun Yoon, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    SENSORS AND ACTUATORS B-CHEMICAL   203   536 - 542  2014.11  [Refereed]

     View Summary

    We report a novel real-time method to monitor the reaction of an organic dye, 5(6)-carboxynaphthofluorescein succinimidyl ester and a CdSe/ZnS quantum dot (QD) using fluorescence spectra of microdroplets formed in a microfluidic device. Dual fluorescence peaks (at lambda = 605 and 670 nm) were observed via a fluorescence energy transfer (FRET) process from the CdSe/ZnS QD to the organic dye; the rate of the chemical reaction of the two reagents was estimated by the ratio of the two fluorescence peaks, defined as the fluorescence intensity ratio. In addition, well-controlled microdroplets were continuously generated (with a diameter of similar to 150 mu m) in the microfluidic device and the reaction time was determined as the length from the mixing point to the sampling point using fluorescence spectroscopy. The fluorescence intensity ratio increased with increasing reaction time after mixing of the two reagents indicating that the chemical reaction was observed directly in the microdroplet. Therefore, the real-time monitoring of the chemical reaction was successfully achieved by measuring the fluorescence intensity ratio as a function of the reaction time. When compared with a conventional batch process, a fast reaction time of &lt;1 s and a high fluorescence intensity ratio was achieved in the microdroplets formed in the microfluidic device. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • Real-time monitoring of chemical reaction in microdroplet using fluorescence spectroscopy

    Takeshi Fukuda, Nayuta Funaki, Tomokazu Kurabayashi, Miho Suzuki, Dong Hyun Yoon, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    SENSORS AND ACTUATORS B-CHEMICAL   203   536 - 542  2014.11  [Refereed]

     View Summary

    We report a novel real-time method to monitor the reaction of an organic dye, 5(6)-carboxynaphthofluorescein succinimidyl ester and a CdSe/ZnS quantum dot (QD) using fluorescence spectra of microdroplets formed in a microfluidic device. Dual fluorescence peaks (at lambda = 605 and 670 nm) were observed via a fluorescence energy transfer (FRET) process from the CdSe/ZnS QD to the organic dye; the rate of the chemical reaction of the two reagents was estimated by the ratio of the two fluorescence peaks, defined as the fluorescence intensity ratio. In addition, well-controlled microdroplets were continuously generated (with a diameter of similar to 150 mu m) in the microfluidic device and the reaction time was determined as the length from the mixing point to the sampling point using fluorescence spectroscopy. The fluorescence intensity ratio increased with increasing reaction time after mixing of the two reagents indicating that the chemical reaction was observed directly in the microdroplet. Therefore, the real-time monitoring of the chemical reaction was successfully achieved by measuring the fluorescence intensity ratio as a function of the reaction time. When compared with a conventional batch process, a fast reaction time of &lt;1 s and a high fluorescence intensity ratio was achieved in the microdroplets formed in the microfluidic device. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • Development of an electrohydrodynamic ion-drag micropump using three-dimensional carbon micromesh electrodes

    Dong Hyun Yoon, Hironobu Sato, Asahi Nakahara, Tetsushi Sekiguchi, Satoshi Konishi, Shuichi Shoji

    JOURNAL OF MICROMECHANICS AND MICROENGINEERING   24 ( 9 ) 095003  2014.09  [Refereed]

     View Summary

    An electrohydrodynamic (EHD) ion-drag micropump using three-dimensional carbon micromesh electrodes was developed. The carbon micromesh electrodes were created by the pyrolysis of SU-8 structures. The carbon electrodes and microchannel were formed on a quartz substrate, and the microchannel was sealed by an SU-8 slab structure. The pumping behaviors were evaluated using Fluorinert as a non-conductive sample solution. The maximum pressure and volume flow rate were approximately 23 Pa and 400 nL/min, respectively, under an applied voltage of 500 V.

    DOI

  • Active microdroplet merging by hydrodynamic flow control using a pneumatic actuator-assisted pillar structure

    Dong Hyun Yoon, Afshan Jamshaid, Junichi Ito, Asahi Nakahara, Daiki Tanaka, Takashiro Akitsu, Tetsushi Sekiguchi, Shuichi Shoji

    Lab on a Chip   14 ( 16 ) 3050 - 3055  2014.08  [Refereed]

     View Summary

    This paper describes a microdroplet merging device that can actively control the merging of various droplets under a wide range of flow conditions, using a simple structure. The microdroplets were trapped and merged in a wide chamber divided by pillars, and their behavior was controlled by two horizontal pneumatic microactuators. Hydrodynamic flow control by the actuation was evaluated numerically, and the trapping and merging of droplets were achieved experimentally and controlled via pressure applied to the microactuators. Furthermore, two independently generated droplets were merged under four different modes, ranging from no merging to four-droplet merging, with different ratios and volumes. The pneumatic actuators allowed not only the control of the number of merged droplets, but also a wide range of applied droplet volumes. The device was fabricated simply using a single-layer PDMS (polydimethylsiloxane) structure, and the continuous merging performance operated using only hydrodynamic flow control without any surfactant. Finally, chemical synthesis of a metal complex was performed by the droplet merging method. Crystallization of the complex was visualized in real time, and the synthesis was verified by ultraviolet-visible spectroscopy. © 2014 the Partner Organisations.

    DOI PubMed

  • Active microdroplet merging by hydrodynamic flow control using a pneumatic actuator-assisted pillar structure

    Dong Hyun Yoon, Afshan Jamshaid, Junichi Ito, Asahi Nakahara, Daiki Tanaka, Takashiro Akitsu, Tetsushi Sekiguchi, Shuichi Shoji

    LAB ON A CHIP   14 ( 16 ) 3050 - 3055  2014.08  [Refereed]

     View Summary

    This paper describes a microdroplet merging device that can actively control the merging of various droplets under a wide range of flow conditions, using a simple structure. The microdroplets were trapped and merged in a wide chamber divided by pillars, and their behavior was controlled by two horizontal pneumatic microactuators. Hydrodynamic flow control by the actuation was evaluated numerically, and the trapping and merging of droplets were achieved experimentally and controlled via pressure applied to the microactuators. Furthermore, two independently generated droplets were merged under four different modes, ranging from no merging to four-droplet merging, with different ratios and volumes. The pneumatic actuators allowed not only the control of the number of merged droplets, but also a wide range of applied droplet volumes. The device was fabricated simply using a single-layer PDMS (polydimethylsiloxane) structure, and the continuous merging performance operated using only hydrodynamic flow control without any surfactant. Finally, chemical synthesis of a metal complex was performed by the droplet merging method. Crystallization of the complex was visualized in real time, and the synthesis was verified by ultraviolet-visible spectroscopy.

    DOI

  • Active microdroplet merging by hydrodynamic flow control using a pneumatic actuator-assisted pillar structure

    Dong Hyun Yoon, Afshan Jamshaid, Junichi Ito, Asahi Nakahara, Daiki Tanaka, Takashiro Akitsu, Tetsushi Sekiguchi, Shuichi Shoji

    LAB ON A CHIP   14 ( 16 ) 3050 - 3055  2014.08

     View Summary

    This paper describes a microdroplet merging device that can actively control the merging of various droplets under a wide range of flow conditions, using a simple structure. The microdroplets were trapped and merged in a wide chamber divided by pillars, and their behavior was controlled by two horizontal pneumatic microactuators. Hydrodynamic flow control by the actuation was evaluated numerically, and the trapping and merging of droplets were achieved experimentally and controlled via pressure applied to the microactuators. Furthermore, two independently generated droplets were merged under four different modes, ranging from no merging to four-droplet merging, with different ratios and volumes. The pneumatic actuators allowed not only the control of the number of merged droplets, but also a wide range of applied droplet volumes. The device was fabricated simply using a single-layer PDMS (polydimethylsiloxane) structure, and the continuous merging performance operated using only hydrodynamic flow control without any surfactant. Finally, chemical synthesis of a metal complex was performed by the droplet merging method. Crystallization of the complex was visualized in real time, and the synthesis was verified by ultraviolet-visible spectroscopy.

    DOI

  • Development of electrohydrodynamic ion-drag micropump using three-dimensional carbon micromesh electrodes

    Yoon, Dong Hyun, Sato, Hironobu, Nakahara, Asahi, Sekiguchi, Tetsushi, Konishi, Satoshi, Shoji, Shuichi

    Journal of Micromechanics and Microengineering    2014.06

  • Effect of Annealing on Magnetostrictive Properties of Fe-Co Alloy Thin Films

    Takashi Nakajima, Teruaki Takeuchi, Isamu Yuito, Kunio Kato, Mikiko Saito, Katsuhiro Abe, Toshio Sasaki, Tetsushi Sekiguchi, Shin-ichi Yamaura

    MATERIALS TRANSACTIONS   55 ( 3 ) 556 - 560  2014.03  [Refereed]

     View Summary

    The effect of the annealing temperature on the magnetostrictive properties of Fe-Co alloy thin films on quartz glass was systematically investigated. The saturation magnetostriction was 56 ppm for the Fe32Co68-sputtered thin film quenched from 673 K, and it increased to 159 ppm with increasing annealing temperature up to 1073K. The magnetostriction above 1093K significantly decreased with the emerging fcc phase in the Fe-Co alloy. SEM images showed that the crystal grains present in the fcc phase aggregated to form a discontinuous surface, which resulted in a decrease in the effective magnetostriction. Measurements of the magnetic properties by vibrating sample magnetometer and magnetic force microscopy revealed the enhancement of the magnetization at the crystal grain boundaries of Fe-Co alloy thin films with large magnetostriction. Thus, the heterogeneity of the magnetization can play a key role in inducing the large magnetostrictive effect.

    DOI

  • Effect of Annealing on Magnetostrictive Properties of Fe-Co Alloy Thin Films

    Takashi Nakajima, Teruaki Takeuchi, Isamu Yuito, Kunio Kato, Mikiko Saito, Katsuhiro Abe, Toshio Sasaki, Tetsushi Sekiguchi, Shin-ichi Yamaura

    MATERIALS TRANSACTIONS   55 ( 3 ) 556 - 560  2014.03  [Refereed]

     View Summary

    The effect of the annealing temperature on the magnetostrictive properties of Fe-Co alloy thin films on quartz glass was systematically investigated. The saturation magnetostriction was 56 ppm for the Fe32Co68-sputtered thin film quenched from 673 K, and it increased to 159 ppm with increasing annealing temperature up to 1073K. The magnetostriction above 1093K significantly decreased with the emerging fcc phase in the Fe-Co alloy. SEM images showed that the crystal grains present in the fcc phase aggregated to form a discontinuous surface, which resulted in a decrease in the effective magnetostriction. Measurements of the magnetic properties by vibrating sample magnetometer and magnetic force microscopy revealed the enhancement of the magnetization at the crystal grain boundaries of Fe-Co alloy thin films with large magnetostriction. Thus, the heterogeneity of the magnetization can play a key role in inducing the large magnetostrictive effect.

    DOI

  • MULTIPLE SIZE-ORIENTED PASSIVE DROPLET SORTING DEVICE AND BASIC APPROACH FOR DIGITAL CHEMICAL SYNTHESIS

    Satoshi Numakunai, Afshan Jamsaid, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji

    2014 IEEE 27TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS)     92 - 95  2014  [Refereed]

     View Summary

    This paper presents a multiple size-oriented passive droplet sorting utilizing a balance between surface free energy and flow force. We proposed a simple multi-stage sorting structure which consists of a microchannel and guide grooves formed in parallel. Passive five different-sized droplets sorting of up to 200 droplets/s is achieved without any active elements. Also, we fabricated a prototype of the integrated micro fluidic system for droplet generation, merging and sorting for digital chemical synthesis.

  • Hydrodynamic on-rail droplet pass filter for fully passive sorting of droplet-phase samples

    Dong Hyun Yoon, Satoshi Numakunai, Asahi Nakahara, Tetsushi Sekiguchi, Shuichi Shoji

    RSC ADVANCES   4 ( 71 ) 37721 - 37725  2014  [Refereed]

     View Summary

    A hydrodynamic droplet pass filter for droplet-phase sample sorting was developed in this study. Using only groove rails, without additional components or external controls, droplets were sorted based on their physical properties. This is the first report of a droplet pass filter used for effective sorting, and the sorting structure provides a novel fluidic component for fluidic circuits for many applications. Depending on the number of rails, we obtained high-pass, low-pass, band-pass, and multi band-pass filters for sorting droplet samples, and their filtration performance was controlled by varying the dimensions of the rail structures. We evaluated in detail the effect of the rail width on sorting, threshold size of droplets sorted into each rail, and capillary number-dependent sample sorting. Furthermore, band-pass droplet sorting, useful for sample quantification, was provided, and multi-step rail ways allowed multi band-pass droplet sorting that was independent of flow conditions. The proposed sorting method does not require any external systems or skilled operation, and thus, it is expected that the device can contribute to on-site sample treatment and analysis in various fields such as medical care or the military.

    DOI

  • Fast and quantitative analysis of branched-chain amino acids in biological samples using a pillar array column

    Yanting Song, Katsuya Takatsuki, Muneki Isokawa, Tetsushi Sekiguchi, Jun Mizuno, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    ANALYTICAL AND BIOANALYTICAL CHEMISTRY   405 ( 25 ) 7993 - 7999  2013.10  [Refereed]

     View Summary

    In this study, a fast and quantitative determination method for branched-chain amino acids (BCAAs), namely leucine, isoleucine, and valine, was developed using a pillar array column. A pillar array column with low-dispersion turns was fabricated on a 20 x 20-mm(2) microchip using multistep ultraviolet photolithography and deep reactive ion etching. The BCAAs were fluorescently labeled with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), followed by reversed-phase separation on the pillar array column. The NBD derivatives of the three BCAAs and an internal standard (6-aminocaproic acid) were separated in 100 s. The calibration curves for the NBD-BCAAs had good linearity in the range of 0.4-20 mu M, using an internal standard. The intra- and interday precisions were found to be in the ranges of 1.42-3.80 and 2.74-6.97 %, respectively. The accuracies for the NBD-BCAA were from 90.2 to 99.1 %. The method was used for the analysis of sports drink and human plasma samples. The concentrations of BCAAs determined by the developed method showed good agreements with those determined using a conventional high-performance liquid chromatography system. As BCAAs are important biomarkers of some diseases, these results showed that the developed method could be a potential diagnostic tool in clinical research.

    DOI

  • Active and Precise Control of Microdroplet Division Using Horizontal Pneumatic Valves in Bifurcating Microchannel

    Dong Hyun Yoon, Junichi Ito, Tetsushi Sekiguchi, Shuichi Shoji

    MICROMACHINES   4 ( 2 ) 197 - 205  2013.06  [Refereed]

     View Summary

    This paper presents a microfluidic system for the active and precise control of microdroplet division in a micro device. Using two horizontal pneumatic valves formed at downstream of bifurcating microchannel, flow resistances of downstream channels were variably controlled. With the resistance control, volumetric ratio of downstream flows was changed and water-in-oil microdroplets were divided into two daughter droplets of different volume corresponding to the ratio. The microfluidic channels and pneumatic valves were fabricated by single-step soft lithography process of PDMS (polydimethylsiloxane) using SU-8 mold. A wide range control of the daughter droplets' volume ratio was achieved by the simple channel structure. Volumetric ratio between large and small daughter droplets are ranged from 1 to 70, and the smallest droplet volume of 14 pL was obtained. The proposed microfluidic device is applicable for precise and high throughput droplet based digital synthesis.

    DOI

  • Controllable Active Micro Droplets Merging Device Using Horizontal Pneumatic Micro Valves

    Afshan Jamshaid, Masaya Igaki, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji

    MICROMACHINES   4 ( 1 ) 34 - 48  2013.03  [Refereed]

     View Summary

    We present an active droplet merging device, which can merge various sizes of micro droplets in different numbers by using pneumatically controlled horizontal PDMS microvalves. The merging part consists of a main and side channels separated by a pillar array. The pillar array structure is contained within a microfuidic channel. The function of the pillar array provides a bypass path to the continuous flow (oil) inside the merging chamber. Droplets are successfully generated within the channel and achieve merging by controlling the selective different numbers and diameters of droplets through varying the flow resistance of main and side channel. In the merging chamber, a droplet will enter and slow down its movement. It will wait and then merge with the sequential droplets. These experiments demonstrate that such a merging device can controllably select and adjust the distance between the different adjacent micro droplets without any generation of sister droplets in the side channel. The device has no desynchronization problems. Thus, it can be applied for efficiently mixing the droplets in various diameters and numbers without changing the structure of the merging chamber. Hence, this device can be a more effective choice when applying microfluidics to chemical and biological applications.

    DOI

  • MEMS LC MICROCHIP WITH LOW DISPERSION AND LOW PRESSURE DROP TURN STRUCTURE USING DISTRIBUTION CONTROLLED MICRO PILLAR ARRAY

    K. Takatsuki, M. Isokawa, Y. Song, A. Nakahara, D. H. Yoon, T. Sekiguchi, J. Mizuno, T. Funatsu, M. Tsunoda, S. Shoji

    26TH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2013)     981 - 984  2013  [Refereed]

     View Summary

    MEMS liquid chromatography (LC) microchip with low dispersion and a low pressure drop turn structure was fabricated. In the turn structure, we used higher density pillar array at the inner side while lower density pillar array was used at the outer side to control inner and outer speed of a sample flow. An LC chip with an improved turn structure can obtain similar theoretical plate number (1233) compared to the previously proposed tapered turn (1135). The necessary inlet pressure is also reduced from 2.7 to 0.4 MPa under a flow rate of 10 mu L/min. These results show the improved turn structure is applicable for fast analysis time under high flow rate conditions.

  • PDMS-CYTOP hybrid structure microwell array chip for total internal reflection fluorescence microscopy.

    Asahi Nakahara, Yoshitaka Shirasaki, Jun Mizuno, Tetsushi Sekiguchi, Osamu Ohara, Shuichi Shoji

    8th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2013, Suzhou, China, April 7-10, 2013     743 - 746  2013  [Refereed]

    DOI

  • Transport properties of Ni-Nb-Zr glassy alloys and hydrogen absorbed alloys

    Rie Y. Umetsu, Hajime Yoshida, Mikio Fukuhara, Shin-ichi Yamaura, Toshio Sasaki, Tetsushi Sekiguchi, Mikiko Saito, Jun Mizuno, Hiroshi Kawarada

    Open Journal of Metal   3   37033 - 37033  2013  [Refereed]

  • Controllable active micro droplets merging device using horizontal pneumatic micro valves

    Afshan Jamshaid, Masaya Igaki, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji

    Micromachines   4 ( 1 ) 34 - 48  2013

     View Summary

    We present an active droplet merging device, which can merge various sizes of micro droplets in different numbers by using pneumatically controlled horizontal PDMS microvalves. The merging part consists of a main and side channels separated by a pillar array. The pillar array structure is contained within a microfuidic channel. The function of the pillar array provides a bypass path to the continuous flow (oil) inside the merging chamber. Droplets are successfully generated within the channel and achieve merging by controlling the selective different numbers and diameters of droplets through varying the flow resistance of main and side channel. In the merging chamber, a droplet will enter and slow down its movement. It will wait and then merge with the sequential droplets. These experiments demonstrate that such a merging device can controllably select and adjust the distance between the different adjacent micro droplets without any generation of sister droplets in the side channel. The device has no desynchronization problems. Thus, it can be applied for efficiently mixing the droplets in various diameters and numbers without changing the structure of the merging chamber. Hence, this device can be a more effective choice when applying microfluidics to chemical and biological applications.

    DOI

  • Matrix Arrangement of Three-Dimensional Sheath Flow for Multiple Component Nanofibers

    Dong Hyun Yoon, Asahi Nakahara, Afshan Jamshaid, Hironobu Sato, Tetsushi Sekiguchi, Shuichi Shoji

    JOURNAL OF SENSORS    2013  [Refereed]

     View Summary

    Multiple core-sheath flow was realized using matrix arrangement of 3D sheath flows. The sheath flow was hydrodynamically formed in a flow shift area which has symmetrical microgrooves on channel walls. Vertical and horizontal alignments of the sample streams are a key element of matrix configuration. The flow shift areas were connected in parallel to achieve horizontal alignment of the sheath flow. The cascade connection of the flowshift areas is used for vertical alignment of the sheath flow. In order to achieve matrix arrangement of core-sheath flow, combination of the parallel and cascade connections was utilized. In this work, the horizontal and vertical configurations of the 2-sample sheath flow were demonstrated. Two streams of the vertically aligned 2-sample sheath flow were joined horizontally, and, as a result, 4-sample core-sheath flow of matrix configuration was obtained successfully.

    DOI

  • Effect of hydrogen absorption on electrical transport properties for Ni36Nb24Zr40 amorphous alloy ribbons

    Rie Y. Umetsu, Hajime Yoshida, Mikio Fukuhara, Shin-Ichi Yamaura, Makoto Matsuura, Toshio Sasaki, Tetsushi Sekiguchi, Mikiko Saito, Jun Mizuno, Hiroshi Kawarada

    Materials Transactions   54 ( 8 ) 1339 - 1342  2013

     View Summary

    Electrical resistivity measurements in the temperature range from 6 to 300K were carried out in order to investigate the effects of the hydrogen absorption on the transport properties of Ni36Nb24Zr40 amorphous alloy ribbon. The electrical resistivity basically behaved negative temperature dependence in all prepared specimens of (Ni0.36Nb 0.24Zr0.40)100-xHx with 0 ≤ x &lt
    15. The absolute value of temperature coefficient of the resistivity, TCR, increased with increasing the amount of the absorbed hydrogen. In addition, it was also clear that the electrical resistivity gradually increased with the time just after electrochemically charging, and tended to saturate after about 800 ks at 300 K. The behavior of the gradual increase in the electrical resistivity with the time was explained by the model including two kinds of the relaxation times, being associated with the migration of the hydrogen from the sample surface. © 2013 The Japan Institute of Metals and Materials.

    DOI

  • Local cell damage-induced apoptosis analysis on microfluidic system

    Risa Kajiyama, Taku Watanabe, Yoshikuni Edagawa, Tetsushi Sekiguchi, Shuichi Shoji

    JOURNAL OF PHARMACOLOGICAL SCIENCES   121   220P - 220P  2013  [Refereed]

  • Preface of the Special Issue of "Bio Sensor and Network Sensing"

    SEKIGUCHI Tetsushi

    The Journal of the Institute of Electrical Engineers of Japan   132 ( 11 )  2012.11

     View Summary

    This article has no abstract.

    CiNii

  • Integration of Pillar Array Columns into a Gradient Elution System for Pressure-Driven Liquid Chromatography

    Yanting Song, Masao Noguchi, Katsuya Takatsuki, Tetsushi Sekiguchi, Jun Mizuno, Takashi Funatsu, Shuichi Shoji, Makoto Tsunoda

    ANALYTICAL CHEMISTRY   84 ( 11 ) 4739 - 4745  2012.06  [Refereed]

     View Summary

    A gradient elution system for pressure-driven liquid chromatography (LC) on a chip was developed for carrying out faster and more efficient chemical analyses. Through computational fluid dynamics simulations and an experimental study, we found that the use of a cross-Tesla structure with a 3 mm mixing length was effective for mixing two liquids. A gradient elution system using a cross-Tesla mixer was fabricated on a 20 mm x 20 mm silicon chip with a separation channel of pillar array columns and a sample injection channel. A mixed solution of water and fluorescein in methanol was delivered to the separation channel 7 s after the gradient program had been started. Then, the fluorescence intensity increased gradually with the increasing ratio of fluorescein, which showed that the gradient elution worked well. Under the gradient elution condition, the retention times of two coumarin dyes decreased with the gradient time. When the gradient time was 30 s, the analysis could be completed in 30 s, which was only half the time required compared to that required for an isocratic elution. Fluorescent derivatives of aliphatic amines were successfully separated within 110 s. The results show that the proposed system is promising for the analyses of complex biological samples.

    DOI

  • Measurement of inflammatory cytokine secretion from human monocytes after inflammasome activation

    Yoshitaka Shirasaki, Asahi Nakahara, Nanako Shimura, Kazushi Izawa, Nobutake Suzuki, Mai Yamagishi, Jun Mizuno, Tetsushi Sekiguchi, Ryuta Nishikomori, Shuichi Shoji, Osamu Ohara

    Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012     1012 - 1014  2012

     View Summary

    Live-cell imaging of inflammatory cytokine secretion from human monocytes was successfully performed on a microfabricated well array chip by time-resolved fluoroimmunoassay using total internal reflection fluorescence microscopy. Some of the lipopolysaccharide primed monocytes secreted small amounts of interleukin-1 beta (IL-1 ), whereas the monocytes stimulated with an ATP signal secreted large amounts of IL-1 from 10% of observed cells. These two types of secretion patterns corresponded to the proposed models of IL-1 secretion, "rescue and redirect" and "terminal release", respectively. Morphological changes in ATP-stimulated cells also indicated that the cells underwent necrotic cell death, also known as "pyroptosis".

  • SIZE-ORIENTED PASSIVE DROPLET SORTING BY USING SURFACE FREE ENERGY WITH MICRO GUIDE GROOVE

    Yu Harada, Dong Hyun Yoon, Tetsushi Sekiguchi, Shuichi Shoji

    2012 IEEE 25TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS)     1105 - 1108  2012  [Refereed]

     View Summary

    We propose a novel droplet sorting method utilizing the reduction of surface free energy. Droplets are guided by a groove due to the decrement of surface energy. 'Guiding power' is different by droplet size and we successfully observed size dependant directional movement of droplets. This principle can be applied to the size-based passive sorting device without any complex operation. Because of that simplicity, this method has large ability to apply for point of care system.

  • CONTINUOUS SIZE-SELECTIVE SEPARATION USING THREE DIMENSIONAL FLOW REALIZED BY MULTILAYER PDMS STRUCTURE

    D. H. Yoon, T. Sekiguchi, J. S. Go, S. Shoji

    2012 IEEE 25TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS)     1205 - 1208  2012  [Refereed]

     View Summary

    This paper proposes a high accuracy fabrication method for multilayer PDMS (polydimethylsiloxane) devices. Based on newly developed multi-stacking process using three-dimensional (3D) alignment marks of the concave-convex pair structures, a multilayer PDMS device was fabricated without skillful handling for alignment. Total misalignment of smaller than 10 mu m is achieved for fabrication of a five-layer PDMS device. The precisely aligned multilayer structure was applied to a novel type of particle separation. By 3D secondary rotation flow in the 3D fluidic microchannel, two types of microparticles of 10 mu m and 20 mu m in diameter were successfully separated with high throughput.

  • Microfluidic active sorting of DNA molecules labeled with single quantum dots using flow switching by a hydrogel sol-gel transition

    M. Haneoka, Y. Shirasaki, H. Sugino, T. Sekiguchi, D. H. Yoon, R. Iizuka, S. Shoji, T. Funatsu

    The 15th International Conference of Miniaturized Systems for Chemistry and Life Sciences: &#181;TAS 2011     1173 - 1175  2011.10

  • Controllable three-dimensional sheath flow with a wide range Reynolds number and its application for efficient cell sorting

    R. Sekine, T. Sakurai, D. H. Yoon, R. Iizuka, T. Sekiguchi, T. Funatsu, S. Shoji

    The 15th International Conference of Miniaturized Systems for Chemistry and Life Sciences: &#181;TAS 2011     1903 - 1905  2011.10

  • Three-dimensional sample flow focusing and positioning for wide range flow speed application

    R. Sekine, D. H. Yoon, T. Sekiguchi, S. Shoji

    ISMM 2011 in Conjunction with the KBCS Spring Meeting     T3 - 022  2011.06

  • Multilayer PDMS (polydimethylsiloxane) device fabrication using concave-convex 3D alignment pair structure

    D. H. Yoon, M. Kawai, T. Sekiguchi, S. Shoji

    ISMM 2011 in Conjunction with the KBCS Spring Meeting     F3 - 091  2011.06

  • Micro/Nanofluidic devices for chemical/biochemical micro total analysis systems

    S. Shoji, K. Kawai, H. Shinohara, D.H. Yoon, J. Mizuno, T. Sekiguchi, T. Arakawa, T. Funatsu

    The 2nd NIMS(MANA)-Waseda International Symposium     OP05  2010.12

  • Selective droplet sampling flow system using minimum number of horizontal pneumatic valves formed by single step PDMS molding

    D. H. Yoon, D. Wakui, T. Sekiguchi, S. Shoji

    The 14th International Conference of Miniaturized Systems for Chemistry and Life Sciences: &#181;TAS 2010     1085 - 1087  2010.10

  • MULTI CHANNEL DROPLET SORTING DEVICE WITH HORIZONTAL PNEUMATIC ACTUATION USING SINGLE LAYER PDMS FLEXIBLE PARALLEL WALLS

    Daisuke Wakui, Shuhei Takahashi, Tetsushi Sekiguchi, Shuichi Shoji

    MEMS 2010: 23RD IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, TECHNICAL DIGEST     144 - 147  2010  [Refereed]

     View Summary

    This paper presents the one intet - five outlets droplet sorting device driven by the horizontal pneumatic actuators. The flexible high aspect ratio PDMS wall structures were proposed to realize five different sorting modes with only two pneumatic actuators. This multi sorting device has very simple structure and is fabricated by single PDMS mold process. Five different mode droplets sorting were confirmed using micro droplets from about 25 mu m to 300 mu m in the diameter.

  • EHD MICRO PUMP USING PYROLYZED POLYMER 3-D CARBON MESH ELECTRODES

    Daisuke Wakui, Naoki Imai, Yasuhiro Nagaura, Hironobu Sato, Tetsushi Sekiguchi, Satoshi Konishi, Shuichi Shoji, Takayuki Homma

    IEEE 22ND INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS 2009)     499 - 502  2009  [Refereed]

     View Summary

    This paper presents the EHD (electro-hydrodynamic) micro pump using 3-D carbon mesh electrodes. The carbon electrodes were fabricated by pyrolysis of SU-8 micro mesh structures [1]. Low temperature SU-8 bonding method under 90 degrees C was developed to realize wafer level carbon structure packaging. The pumping behaviors were evaluated using fluorinert as a sample solution. The maximum pressure and volume flow rate are about 23Pa and 400nL/min under applied voltage of 500V.

  • Comparison of a microfluidic gas-intake devices with pillar-type and microfluidic membrane-type structures

    M. Amano, T. Arakawa, H. Sato, T. Sekiguchi, S. Shoji, H. Kudo, H. Saito, K. Mitsubayashi

    ECS Transactions   16 ( 14 ) 117 - 122  2008

     View Summary

    A microfluidic gas-intake device for measurement of gaseous substances was fabricated and tested. The gas-intake device has a window that provides direct absorption of gas into liquid in microchannels the membrane-type microfluidic device which uses a gas permeability of the PDMS membrane for gas-intake is fabricated and compared gas intake efficiency to the gas-intake device using the dissolution velocity of oxygen into D1 water channel. The degree of oxygen saturation was significantly improved (17.5 %) in case of the pillar-type device. This indicates that the pillar-type microstructure is effective for the gas-intake purpose. © The Electrochemical Society.

    DOI

  • 3D sheath flow using hydrodynamic position control of the sample flow

    Hironobu Sato, Yutaka Sasamoto, Daisuke Yagyu, Tetsushi Sekiguchi, Shuichi Shoji

    JOURNAL OF MICROMECHANICS AND MICROENGINEERING   17 ( 11 ) 2211 - 2216  2007.11  [Refereed]

     View Summary

    3D sheath flow was realized using hydrodynamic position control of the sample flow. The symmetric microgrooves formed on the channel walls were utilized to generate local directional streams. The sample introduced into the grooved area was shifted to the center region of the microchannel, and 3D sheath flow was formed passively. Using CFD ( computational fluid dynamics) simulation, the flow shift area was designed to achieve 3D sheath flow no longer than 500 mu m in channel length. Sample flow shift behavior was observed by using a confocal microscope. Since the structure of the inlets was very simple, it was possible to fabricate an in-plane multi-sample 3D sheath flow device. As a demonstration, a two-sample 3D sheath flow device was fabricated. The separated two-sample 3D sheath flow configuration was clearly observed.

    DOI

  • Multiple core-sheath liquid transfer using matrix arrangement of 3D sheath flows

    H.Sato, Y.Sasamoto, T.Sekiguchi, T.Homma, S.Shoji

    International Conference on Miniaturized Systems for Chemistry and Life Sciences (mTAS 2007) Paris, France     1571 - 1573  2007.10

  • Flow type electrochemical immuno sensing systems

    Yutaka Yamaguchi, Nobuo Honda, Masashi Inaba, Tetsushi Sekiguchi, Shuichi Shoji

    2006 IEEE SENSORS, VOLS 1-3     486 - +  2006  [Refereed]

     View Summary

    A novel flow type electrochemical immuno sensing system using 3-D comb electrodes, which enables high-speed enzyme immunoassay on a single microchip, has been developed. A trap-and-release system of magnetic beads and a sheath flow sorting system are integrated on the chip. The integrated system realizes repeatable sample preparation and sensing. Using this system, AFP detection in the range from 25ng/mL to 500ng/mL was obtained within 30 minutes. This system can be applied widely for high sensitive enzyme immunoassays.

  • 臨床現場とメーカをつなぐ臨床工学部門

    関口哲志

    Clinical Engineering   15 ( 7 ) 721 - 722  2004.07

  • 新しい術中モニタリング

    関口哲志

    Clinical Engineering   15 ( 7 )  2004

  • 企業が考える臨床技士教育

    関口哲志

    Clinical Engineering   14 ( 7 ) 705 - 707  2003.07

  • 実験的発作性頻拍時の胃粘膜二酸化炭素分圧の連続モニタ

    崎尾秀彰, 上野和徳, 関口哲志, 永井裕子

    日本救急医学会誌(JJAAM)   ( 14 ) 433 - 439  2003

  • Particles and molecules handling in micro channels

    S. Shoji, K. Tashiro, T. Sekiguchi, H. Sato, N. Honda, T Funatu

    Lab-on-a-Chip: Miniaturized Systems for (Bio) Chemical Analysis and Synthesis     205 - 214  2003

     View Summary

    High performance flow monitoring systems are needed to monitor the particles and biomolecules flow in micro channels. For the design of microfluidic devices and systems, the finite element analysis tools play an important role. These systems are useful to evaluate the correspondence between the computational fluid dynamics (CFD) simulation and the actual flow in micro channels. The micro flow cell realizing 3D sheath flow was designed and the prototype was fabricated and evaluated. Since the flow distribution of the sample is critically changed with the pressure and the flow rate of the carrier, the 3D CFD analysis is indispensable to design the micro flow cell. The principle of 3D sheath flow is applicable to realize particles and biomolecules observation and handling systems. Novel micro flow switches using thermal gelation of methylcellulose (MC) have been developed. Since the local plug is formed illuminating the laser beam, the flow can be stopped at any point in the microchannels. The switching time of about 1 sec both open-to-close and close-to-open was achieved. By using the MC as a carrier flow, DNA, protein and biological cell sorting micro flow systems can be realized in the simple 2D microchannel structures. © 2003 Elsevier B.V. All rights reserved.

    DOI

  • Micro Flow Devices and Biomoleculer Handling in Micro Flow Channels

    S.Shoji, N.Honda, H.Sato, K.Tashiro, T.Sekiguchi, T.Funatsu

    Proc. 1st Int. Symp. On Ultramicrochemical Process:ISUP 2002     83 - 89  2002

  • Biomolecules sorting system using thermal gelation of methyl cellulose solution

    S. Ikeda, K. Tashiro, T. Sekiguchi, S. Shoji, H. Makazu, Y. Shirasaki, T. Funatsu, S. Tsukita

    2002 International Microprocesses and Nanotechnology Conference, MNC 2002     170 - 171  2002

     View Summary

    A novel automatic biomolecules sorter using thermal gelation of methyl cellulose (MC) solution was realized. In our previous work, we already reported the sol-gel transformation of MC could be used for the flow switch. The flow switch was applied for the prototype of the particles handling system with manual control. The sorting time in this case was about 2 seconds. However the time of sol-gel transformation was estimated within a second. To achieve faster sorting speed, we fabricated a PC controlled sorting system consisting of an automatic fluorescence sample detector, focused IR laser source, and two galvano mirrors for switching and scanning of the laser. As a result the sorting time was reduced to around 100 msec.

    DOI

  • A Novel Biomolecule Sorter Using Thermosensitive Hydrogel in Micro Flow Systems

    Y.Shirasaki, H.Makazu, K.Tashiro, S.Ikeda, T.Sekiguchi, S.Shoji, S.Tsukita, T.Funatsu

    Proc. Micro Total Analysis Systems 2002; μTAS2002, Nara     925 - 927  2002

    DOI

  • A PARTICLES AND BIOMOLECULES SORTING MICRO FLOW SYSTEM USING THERMAL GELATION OF METHYL CELLULOSE SOLUTION

    K. TashiroS, IkedaT, SekiguchiS, ShojiH. MakazuT, FunatsuS. Tsukita

    Micro Total Analysis Systems 2001    2001.10  [Refereed]

    DOI

  • Continuous measurement of gastric luminal CO2 (PgCO2) and Cardiac Output (CCO) through the perioperative period in the patients receiving surgery using cardiopulmonary bypass (CPB)

    Takasuke Imai, Tetsushi Sekiguchi, Yuko Nagai, Takushi Morimoto, Toshihisa Nosaka, Chieko Mitaka, Kousi,Makita, Makoto Sunamori

    30th international education &amp; scientific symposium on critical care medicine. San Francisco California.USA    2001.02

  • Micro flow switches using thermal gelation of methyl cellulose for biomolecules handling

    K Tashiro, S Ikeda, T Sekiguchi, H Sato, S Shoji, H Makazu, K Watanabe, T Funatsu, S Tsukita

    TRANSDUCERS '01: EUROSENSORS XV, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2     932 - 935  2001  [Refereed]

     View Summary

    Novel micro flow switches using thermal gelation of methyl cellulose (MC) are proposed. The Cross-linked methyl cellulose changes its state from liquid to gel by elevating the temperature. We applied this phenomenon to form a solid structure by irradiating a focused IR laser beam at any points inside of the micro channel. The switching time is fast enough for both open-to-close and close-to-open. By using the MC of optimal concentration as a carrier flow, biomolecules handling systems are realized without any mechanical valve structures.

  • 電気学会マイクロ化学分析システム調査専門委員会報告書「マイクロ化学分析システム(μ‐TAS)技術動向」

    関口哲志他

    マイクロ化学分析システム調査専門委員会    2000.12

  • 臨床工学技士 21世紀の夢 -HELP? HELP!

    関口哲志

    Clinical Engineering   11 ( 11 ) 941 - 944  2000.11

  • Immunological Helicobacter pylori urease analyzer based on ion-sensitive field effect transistor

    T Sekiguchi, M Nakamura, M Kato, K Nishikawa, K Hokari, T Sugiyama, M Asaka

    SENSORS AND ACTUATORS B-CHEMICAL   67 ( 3 ) 265 - 269  2000.09  [Refereed]

     View Summary

    Immunological Helicobacter pylori (H. pylori) urease analyzer (HPUA), based on a solid-phase tip coated with a monoclonal antibody toward H. pylori's urease and ion-sensitive field effect transistor (ISFET), was developed. In this system, H. pylori urease adsorbed on the solid-phase tip, after a 15-min immunological reaction with gastric mucus sample solution, was measured with a urease analyzer composed of a flow-through cell for urea solution equipped with the measuring and reference ISFETs. The pH change (Delta pH) of urea solution after 55 s of the enzymatic reaction inside the tip was measured by withdrawing about 1 mu l of the urea solution toward the upstream of the tip, where the measuring ISFET is installed. It was confirmed that the present system could detect 0.2 mIU/ml of H. pylori urease. Clinical evaluations of the system were performed for 119 patients using urea breath test (UBT) as a gold standard, resulting in the sensitivity = 33/36 = 92% and specificity = 81/83 = 98%, respectively. (C) 2000 Elsevier Science S.A. All rights reserved.

  • 静電駆動を用いた蠕動型マイクロポンプの試作

    佐藤寛暢, 関口哲志, 庄子習一

    第二回化学とマイクロシステム研究会 姫路    2000.09

  • 生体用テレメトリ開発における電磁ソフトウエアシミュレータの有用性の検討

    石塚洋介, 伊藤雄一, 関口哲志, 庄子習一

    第39回日本ME 学会大会 医用電子と生体工学   38   269  2000.05

  • 開心術における舌下組織PCO2の測定

    井上久, 佐藤勲, 仁杉直子, 三宅実砂, 佐藤陽二, 池上敬一, 中川儀英, 永井裕子, 関口哲志

    日本集中治療医学会総会     215  2000.03

  • 新しい医療用マイクロ化学・生化学分析システム -uTAS-

    庄子習一, 関口哲志

    SUT BULLETIN   ( 5 ) 38 - 43  2000

  • Evaluation of PCO2 measurement using a gastric air tonometer located in non-mixing solution.

    Yoji Sato, Hisashi Inoue, Keiichi Ikegami, Tomoko Seki, Fumio Morimoto, Yuko Nagai, Tetsushi Sekiguchi, Michihiro Nakamura

    20th International Symposium on Intensive Care and Emergency Medicine   4 ( 1 ) 151  2000

  • Detection of perfusion failure during open heart surgery with sublingual PCO2

    Hisashi Inoue, Isamu Sato, Naoko Hitosugi, Yoshito Takano, Misa Miyake, Yoji Sato, Keiichi Ikegami, Yuko Nagai, Tetsushi Sekiguchi Michihiro Nakamura

    20th International Symposium on Intensive Care and Emergency Medicine   4 ( 1 ) 157  2000

  • Design and simulation of particles and biomolecules handling micro flow cells with three-dimensional sheath flow

    K Tashiro, T Sekiguchi, S Shoji, T Funatsu, W Masumoto, H Sato

    MICRO TOTAL ANALYSIS SYSTEMS 2000, PROCEEDINGS     209 - 212  2000  [Refereed]

     View Summary

    In order to realize high performance particles and biomolecules handling systems, micro flow cell realizing three-dimensional (3-D) sheath flow was designed and the first prototype was fabricated. A finite element fluidic analysis is applied to realize optimal design of the flow cell. Especially, the structure of the sample injection part was considered to realize 3-D sheath flow. The high resolution flow monitoring method was studied and was applied to evaluate the flow behavior in the first prototype. The results indicated that the two steps introduction of the carrier flow is quite effective to put the sample flow away from the channel wall. This is very useful to avoid adsorption of the particles and the biomolecules on the wall due to the small flow rate near the wall. A simple micro flow switch for biomolecular separation is also proposed.

  • 救急現場でのスパゲッティ症候群の解消-新しい心電図検出法(コードレス電極)の開発-

    佐藤陽二, 関口哲志

    第27回日本救急医学会総会     193  1999.11

  • 医用無線通信機器とEMC -病院内複数機器からのエミッションの影響について-

    関口哲志, 松村文幸, 坂田博史, 稲井 隆, 原田 元, 保坂栄弘, 佐藤陽二

    電気学会全国大会    1999.03

  • 座談会:臨床工学技士これまでの十年これからの十年

    関口哲志

    Clinical Engineering   10 ( 7 ) 666 - 676  1999

  • Immunological rapid urease test for detecting Helicobacter pylori: Comparative study of biopsy specimens and gastric mucus

    T. Sato, M. A. Fujino, Y. Kojima, F. Kitahara, T. Nakamura, A. Morozumi, K. Nagata, T. Sekiguchi, M. Nakamura, H. Hosaka

    Digestive Endoscopy   11 ( 1 ) 42 - 46  1999

     View Summary

    A variety of reliable methods are available for the detection of H. pylori during upper gastrointestinal endoscopy. We evaluated the clinical utility of an analyzer for H. pylori urease composed of a solid-phase tip coated with a monoclonal antibody against H. pylori urease and ion-sensitive field effect transistor-based pH sensor system. Samples of both gastric mucus and gastric mucosal specimens were collected and the results from this system were compared. Sensitivity and specificity were 97% and 100% for mucus samples and 92% and 97% for mucosal specimens in the present system
    compared to 95% and 96% for histological examination, 92% and 100% for bacteriological test, and 89% and 100% for rapid urease test, respectively. These results confirmed that the present system had high clinical sensitivity and specificity, especially for testing of mucus samples. This method has the advantage of requiring only one sample per patient because mucus can be collected from a broad area of the stomach lumen by stroking the mucosal surface with a brush.

    DOI

  • 開心術症例の胃腔PCO2連続モニタ

    根本真人, 高橋宏行, 崎尾秀彰, 関口哲志, 永井裕子

    第38回日本麻酔学会関東甲信越大会    1998.09

  • Gastric P-CO2 monitoring system based on a double membrane type P-CO2 sensor

    T Sekiguchi, Y Nagai, T Makino, K Ohno, M Nakamura, H Hosaka, HSB Sakio, S Ohtsu, H Takahashi

    SENSORS AND ACTUATORS B-CHEMICAL   49 ( 3 ) 171 - 178  1998.07  [Refereed]

     View Summary

    Gastric P-CO2 monitoring during canine hemorrhagic shock encountered occasional baseline drift to higher direction when conventional P-CO2 sensor was used. As a result of chemical analysis of gastric juice of dogs and human, hydrogen sulfide and acetic acid were identified as causative compounds. It was speculated that these weak acid molecules would permeate gas-permeable silicone membrane to be accumulated in the inner solution of Severinghaus-type P-CO2 sensors. In order to prevent this phenomenon, double-membrane type P-CO2 sensor was constructed. In this sensor, acid-neutralizing solution was installed between the inner and the outer membranes in order to dissociate weak acid molecules into corresponding ions, which can not diffuse into the inner silicone membrane. In addition, Cu2O particles were mixed in the inner silicone membrane to trap hydrogen sulfide in this membrane. It was confirmed by experiments in vitro that the readings of improved gastric P-CO2 sensors were not affected by acetic acid or hydrogen sulfide. As a result of a preliminary clinical evaluation, continuous monitoring of gastric was carried out for 72 h without detectable baseline drift or the change of sensitivity. (C) 1998 Elsevier Science S.A. All reserved.

  • 近接して複数の医療機器が使用される医療現場で、医療用通信機器が使用される場合の問題点は何か?

    関口哲志, 松村文幸, 坂田博史, 稲井 隆, 原田 元, 保坂栄弘

    第4回医療電磁環境研究会     38 - 45  1998.07

  • 医用テレメータ開発における病院内電磁環境の問題点について

    関口哲志, 松村文幸, 坂田博史, 稲井 隆, 原田 元, 保坂栄弘

    第37回日本エム・イー学会大会     364  1998.05

  • 2種類の胃内腔PCO2連続モニタの比較検討

    高橋宏行, 大津 敏, 崎尾秀彰, 関口哲志, 永井裕子

    第13回日本SHOCK学会ポスターセッション    1998.04

  • 電気学会マイクロ化学センサ調査研究専門委員会報告書「マイクロ化学センサの技術動向」

    関口哲志他

    マイクロ化学センサ調査専門(委)    1998

  • 胃内腔PCO2連続測定装置の開発

    上野和徳, 田中禎一, 崎尾秀彰, 関口哲志, 永井裕子, 中村通宏

    第12回日本SHOCK学会ポスターセッション    1997.05

  • A very low-power consumption wireless ECG monitoring system using body as a signal transmission medium

    T Handa, S Shoji, S Ike, S Takeda, T Sekiguchi

    TRANSDUCERS 97 - 1997 INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS AND ACTUATORS, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2     1003 - 1006  1997  [Refereed]

     View Summary

    A very low-power consumption wireless system for monitoring ECG (ElectroCardioGram) is proposed. It consists of ECG detector/transmitter located on the chest and the relay transmitter placed at the wrist. Between the detector part and relay transmitter, the signal is send as the AC micro current flown through the tissue of the body. Since this method obtains very low-power signal transmission of about 8 mu W(400mV(RMS) x 20 mu A(RMS)), the system can be driven by very small power source like a thin film battery. The similar wireless transmission method can be applied for other medical signal/data sensing micro systems sharing the same relay transmitter.

  • 生体情報計測用マイクロシステムの研究-心電位計測用マイクロシステム-

    半田 崇, 庄子習一, 武田 朴, 関口哲志

    電気学会全国大会   ( 3 ) 125 - 126  1996

  • 血圧トランスデューサの性能改善

    小沢秀夫, 浜谷哲男, 武田 朴, 兵後充史, 関口哲志, 江刺正喜

    第25回日本ME学会ポスターセッション     500  1986

  • "-Preparation of Polysiloxanes from Silicic Acid. V. - Condensation of Silicic Acid Butyl Esters and Formation of Silica Fiber from the Ester Solutions

    Yoshimoto Abe, Tetsushi Sekiguchi, Takahisa Misono

    JOURNAL OF POLYMER SCIENCE:Polymer Chemistry Edition   22 ( 3 ) 925 - 927  1984.03

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Books and Other Publications

  • 新しい術中モニタリング

    Clinical Engineering

    秀潤社  2004.07

  • 臨床現場とメーカをつなぐ臨床工学部門

    Clinical Engineering

    秀潤社  2004.07

  • 企業が考える臨床工学技士教育

    Clinical Engineering

    秀潤社  2003.07

  • Particles and molecules handling in micro channels” Miniaturized Systems for (Bio)Chemical Analysis and Synthesis

    Lab-on-a-chip

    Elsevier  2003

  • 「臨床工学技士 21世紀の夢 」

    Clinical Engineering

    秀潤社  2000.11

  • 「新しい医療用マイクロ化学・生化学分析システム -μTAS-」

    東京理科大学出版会  2000

  • 「マイクロ化学分析システム(μ‐TAS)技術動向」

    電気学会  2000

  • 臨床工学技士これまでの十年これからの十年

    Clinical Engineering

    秀潤社  1999.10

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Misc

  • Functional SU-8-PET composite microchip including Au microdot array fabricated by low temperature polymer bonding

    R. Yamamoto, K. Sueyoshi, K. Otsuka, T. Kasahara, A. Nakahara, D.H. Yoon, J. Mizuno, T. Sekiguchi, S. Shoji

    8th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, IEEE NEMS 2013     418 - 421  2013  [Refereed]

    DOI

Industrial Property Rights

  • 圧電型発電装置及びその製造方法

    関口 哲志, 佐々木 敏夫, 笹川 健太, 中嶋 宇史

    Patent

  • ピラーアレイミキサー及びこれを使用した試料処理装置

    庄子 習一, 関口 哲志, 中西 完貴

    Patent

  • 電界効果型トランジスタおよび集積回路

    5648812

    川原田 洋, 水野 潤, 関口 哲志, 齋藤 美紀子

    Patent

Awards

  • 2019 Micromachines Best Paper Award

    2020.02   MDPI   Size-Dependent and Property-Independent Passive Microdroplet Sorting by Droplet Transfer on Dot Rails

    Winner: D.H. Yoon, D. Tanaka, T. Sekiguchi, S. Shoji

  • CHEMINAS Poster Award 1st Prize

    2011.06  

Research Projects

  • Construction of multiple micro interfaces using 3D microfluidic devices and application to functional chemical reactions

    Project Year :

    2020.04
    -
    2023.03
     

  • 細胞内微小サンプル計測を目的としたマイクロ・ナノドロップレットハンドリング

    Project Year :

    2016.04
    -
    2019.03
     

     View Summary

    ①微小なスケール(数ミクロン~サブミクロン)のマイクロドロップレットの安定的作製技術の確立。 これまでに研究代表者のグループが開発してきたマイクロ流体デバイスは、基本的にひとつずつマイクロドロップレットを作製する構造になっており、大量のサンプル処理を考えた場合、生産性が問題となる。そこで本研究では、イオンビームでSiに直接50CH程度の多チャンネル流路を形成する方法でデバイスを作製し、3ミクロン程度のドロップレットの多量かつ安定な作製に成功した。②微小サンプルのドロップレット内への内包技術の確立 当年度は主に油層/液相の2層からなる微小ドロップレットの薬理への応用を試みた。プライマーでコーティングされた微小磁気ビーズを油層/水層の2層からなるドロップレットにDNAとともに個別に内包したのち、ドロップレット内でDNAと各種薬品を反応させその様子を観察することにより、特定の薬品にのみ反応し特殊なたんぱく質を分泌するDNA配列の特定に成功した。③マイクロドロップレットの選択的操作技術の確立 Aの微小ドロップレットとBの微小ドロップレットを一つずつ確実にトラップし、その後トラップした場所でABの1対1の融合を可能とするマイクロ流体デバイスを開発し、実際に動作を確認した。研究代表者のグループは、これまでもドロップレット融合デバイスの開発に成功しているが、今回の研究では必ずA(試料)とB(試薬)を一つずつ融合させることが可能な点に特徴がある。④ 選択された微小サンプルに対する薬品等の刺激方法の確立 今年度新規に開発に成功した、超撥水表面を実現する構造体を応用して、その表面にマイクロドロップレットをのせてハンドリングを行うことにより、ドロップレット同士の新規な融合方法を検討中である。H28年度の研究実施計画をほぼすべて実施しており、かつ更なる発展や応用が見込める。また、論文・学会発表等の業績も着実に上がっているため。基本的にはこれまでの研究方針を着実に推進していくことで当初目標は達成可能である。ただし、研究グループ内でマイクロ流体デバイスに精通している技術者が少なくなったため、今後ナノ・ライフ創新研究機構スタッフの協力や、新規人材の育成によるメンバーの補強等、工数の確保には留意する必要がある

  • マイクロナノバイオトランスポート機構を基軸にした肝臓組織再生

    科学研究費助成事業(早稲田大学)  科学研究費助成事業(基盤研究(A))

    Project Year :

    2013
    -
    2016
     

     View Summary

    (1)再生肝臓組織の再構築組織モデル:積層型培養モデルとマイクロ流路型(MEMS)培養モデルの2種類のアプローチによって、3次元組織を再構築して、組織内の血管化の要因を検討した。(2)組織再構築を実現するための増殖因子の役割:現在増殖因子の濃度勾配を組織内でリアルタイムに計測する手段が開発されていない。そこで、組織のサンプル標本を直接enzyme-linked immunosorbent assay (ELISA) による方法によって、サンプル組織全体の平均値として計測して、その影響に関して検討を行った。増殖因子の濃度場の把握が重要で、今後さらに検討が必要である。(3)星細胞の役割:積層型培養モデルを用いて、星細胞の介在が、肝細胞と血管内皮細胞による3次元組織形成に影響を及ぼす事を明らかにした。(4)血管内皮前駆細胞による血管網形成:分化機能を有する血管内皮前駆細胞を用いて血管網形成を試みた。血管内皮前駆細胞から、多種類の増殖因子が分泌して、血管網を誘導する事が知られている。そこで、積層型培養モデルにおいて、前駆細胞の影響により、3次元血管網が顕著に増殖して、前駆細胞の活用の重要性が明らかになった。(5)葉状仮足による血管網形成の促進:血管網が伸展する先端には、葉状仮足が増殖因子の濃度勾配の方向に伸長する。即ち、濃度勾配により血管網の伸展方向の制御が可能になる。そこで、葉状仮足と3次元血管網形成との関係を明らかにした。(6)マイクロ流路型培養モデルによるアプローチ:MEMS技術を活用して、マイクロ流路を作成し、細胞、増殖因子及び足場の三要素をマイクロ環境で統合する方法が有効である。特に間質流による影響が顕著であることが明らかになり、新しい血管網形成の重要な手法になる事を示した。

  • 低炭素社会の実現に向けた人材育成ネットワークの構築と先進環境材料・デバイス創製(GRENE)

    Project Year :

    2011
    -
    2016
     

  • マイクロフルイディックエンジニアリングの深化と生体分子高感度定量計測への展開

    科学研究費助成事業(早稲田大学)  科学研究費助成事業(基盤研究(S))

    Project Year :

    2011
    -
    2015
     

     View Summary

    1.研究の目的
    微小発光サンプルの光学的超高感度定量計測を可能とすべく、on demand型の光学的補助機能を組み込んだマイクロ流体デバイスを開発する。具体的にはマイクロ流体内超高感度光学観察場のon demand構築技術及びそれをサポートする周辺技術の構築、並びに超高感
    度光学的定量計測に適した微小サンプル前処理技術を開発する。H25年度は、トータルシステムのプロトタイプ製作と評価、及び得られた結果の要素技術へのフィードバックを目的とする。
    2.研究実績の概要
    (1)「システム化による実際のバイオ・生体試料等への応用と要素技術へのフィードバック」(庄子・竹山・関口) 三次元シースフローデバイスを応用した人工血管の作製に成功した。LCチップの構造に改良を加え、超高感度なたんぱく質の分析を可能とした。バイオサンプルを扱うに当たり、要求仕様にしたがってマイクロ流体デバイスの設計変更を行った。(2)「マイクロ流体デバイスを利用したバイオサンプルの新しい前処理法と観察法の検討」(竹山・関口・水野)GEL Micro droplet(GMD) に一つずつ細菌を入れ、培養・観察を行う技術を応用して、単一細胞の機能解析を進めた。細胞内に蛍光ナノプローブを導入して培養を行ったのち、人工的に細胞死を誘引させることで、アポトーシスのメカニズムのリアルタイムイメージングに成功した。(3)「マイクロ流体デバイスシステム化のための直接接合技術の検討」(庄子・水野) 同種/異種基板材料同士の表面処理技術と直接接合技術を確立した。これを応用して流体デバイス型有機ELの作製に初めて成功した。
    【連携研究者】早稲田大学 竹山研究室 モリ テツシ(細胞関連)、同 ナノ理工学研究機構 尹棟鉉(ドロップレット関連)、埼玉大学 工学部 鈴木美穂、福田 武司(バイオプローブ関連)、帝京平成大学 薬学部 枝川義邦(薬理関連)

  • Establishment of Electrochemical Device Engineering

    Project Year :

    2008
    -
    2012
     

     View Summary

    Based on the researches for development of functional materials with the control of solid-liquid interface and for development of devices with the practical use of nano- and meso-structures and phenomena at the interface, the establishment of Electrochemical Device Engineering was promoted. To establish Electrochemical Device Engineering on the basis of Electrochemical Nanotechnology, the practical devices utilizing the outcome of research and the dimensions for appearance of function and design of solid-liquid interface were set as the warp and weft of this academic discipline.

  • 特異構造金属・無機融合高機能材料開発共同研究プロジェクト

    Project Year :

    2010
    -
     
     

  • 4大学ナノ・マイクロファブリケーションコンソーシアム

    Project Year :

    2010
    -
     
     

  • 大口径ダイヤモンド基板によるグリーンインバータ基礎技術

    Project Year :

    2010
    -
     
     

  • ダイヤモンドMOSFETを使用したグリーンインバータ開発による低炭素社会の実現

    Project Year :

    2010
    -
     
     

  • Development of Micro Fluidic Systems for Real Time Function Analysis of Single Biomolecules

    Project Year :

    2007
    -
    2010
     

     View Summary

    Micro fluidic Systems for real time function analysis of single biomolecules were proposed and demonstrated. By applying MEMS and μTAS technologies, functional particular cell trapping and culture micro flow systems, a damage free cell rapture device, high through-put bio molecules sorting systems and high performance biomolecules analysis chips have been developed. Multi sample treatment and handling system technologies are also proposed and demonstrated.

  • ナノテクノロジー要素技術養成プログラム

    Project Year :

    2004
    -
    2009
     

  • 早稲田大学カスタムナノ造形・デバイス評価支援事業

    Project Year :

    2007
    -
     
     

  • 地域結集型研究開発プログラム「都市の安全・安心を支える環境浄化技術開発」

    Project Year :

    2006
    -
     
     

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Presentations

  • 化学合成への応用に向けた有機溶媒のマイクロドロップレット形成手法の構築

    湯成河, 服部翔平, 野崎義人, 尹棟鉉, 田中大器, 藤田博之, 秋津貴城, 関口哲志, 庄子習一

    日本化学会 第100春季年会  日本化学会

    Presentation date: 2020.03

  • マイクロ・ナノ流体工学の光学・バイオ・化学への応用

    庄子習一, 桑江博之, 尹棟鉉, 田中大器, 関口哲志, 水野潤, 野崎義人, 笠原崇史, 秋津貴城  [Invited]

    電子情報通信学会 システムナノ技術に関する特別研究専門委員会(SNT)第3回研究会  (東京)  電子情報通信学会

    Presentation date: 2020.01

  • 圧電ポリマー材料を用いた振動発電の応用例

    関口哲志, 佐々木敏夫, 野崎義人, 庄子習一, 瀧口徹, 鎌田裕樹, 笹川健太, 小島大知, 菅谷拓央  [Invited]

    早稲田大学 エネルギーハーベスティング コンソーシアム・アンビエントロニクス研究所 合同シンポジウム  (早稲田大学、東京)  早稲田大学 エネルギーハーベスティング コンソーシアム・アンビエントロニクス研究所

    Presentation date: 2019.12

  • High Efficient Synthesis of Functional Compounds by Microfluidic Device

    D. Tanaka, D.H. Yoon, Y. Nozaki, T. Sekiguchi, T. Akitsu, S. Shoji  [Invited]

    The 4th International Symposium on Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development (iLIM-4)  (Sendai, Japan) 

    Presentation date: 2019.10

  • Sequential Formation of Daughter Droplets by Breakup of Microdroplets into Bypass Channel

    S. Hattori, D.H. Yoon, Y. Nozaki, T, Isano, H. Yamagata, H. Fujita, T. Sekiguchi, S. Shoji

    The 23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences  (Basel, Switzerland) 

    Presentation date: 2019.10

  • Simultaneous Microdroplets Generation by Tall Breakup Induced with Multi-Branch Channel

    S. Kajiya, D.H. Yoon, Y. Nozaki, T. Isano, H. Yamagata, H. Fujita, T. Sekiguchi, S. Shoji

    The 23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences  (Basel, Switzerland) 

    Presentation date: 2019.10

  • Establishment of Labo-In-A-Microdroplet for Azo Compound Synthesis

    D. Tanaka, S. Sawai, T. Sugaya, Y. Nozaki, D.H. Yoon, T. Isano, H. Yamagata, H. Fujita, T. Sekiguchi, T. Akitsu, S. Shoji

    The 23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences  (Basel, Switzerland) 

    Presentation date: 2019.10

  • Construction of a Well-Operable Crystallization Method for Chemical Analysis Applying Microdroplet Device

    S. Hattori, D. Tanka, D.H. Yoon, T. Sekiguchi, Y. Nozaki, T. Akitsu, S. Shoji

    The 4th Conference on Micro Fluidic Handling Systems (MFHS 2019)  (Enschede, The Netherlands) 

    Presentation date: 2019.10

  • High-Efficiency Dibromination of Organic Compound in Microfluidic Channel of Si Pillar Array Directly Coated with Iron Catalyst

    T. Sugaya, D. Tanaka, D.H. Yoon, Y. Nozaki, T. Sekiguchi, T. Akitsu, S. Shoji

    The 20th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2019) 

    Presentation date: 2019.06

  • Oil-In-Water Droplet Formation in Hydrophobic PDMS Device Using Three-Dimensional Protruded Taper Channel

    C. Tang, D.H. Yoon, T-Sekiguchi, S, Shoj

    The 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2018)  (Kaohsiung)  IEEE

    Presentation date: 2018.11

  • Fabrication of Long Myotube Bundles in Three-Dimensional Gel Scaffolds with Oriented Cellulose Nanofibers

    K. Imato, K. Yoneda, T. Tanaka, D.H. Yoon, T. Sekiguchi, S. Shoji, N. Takeda

    5th Tissue Engineering and Regenerative Medicine International Society World Congress 2018, (5th TERMIS World Congress 2018) 

    Presentation date: 2018.09

  • Fabrication of Long Luminant Tissues in Three-Dimensional Gel Scaffolds with Oriented Cellulose Nanofibers

    T. Tanaka, K. Imato, K. Yoneda, D.H. Yoon, T. Sekiguchi, S. Shoji, N. Takeda

    5th Tissue Engineering and Regenerative Medicine International Society World Congress 2018, (5th TERMIS World Congress 2018)  (Kyoto) 

    Presentation date: 2018.09

  • High Efficiency Synthesis of Br Addition Ligand by Microfluidic Device

    D. Tanaka, W. Kawakubo, K. Takahashi, D.H. Yoon, T. Sekiguchi, T. Akitsu, S. Shoji

    43rd International Conference on Coordination Chemistry (ICCC 2018)  (Sendai) 

    Presentation date: 2018.07

  • Design Optimization and Fabrication of Simple Printable Piezoelectric Energy Harvest Device

    K. Sasagawa, D.H. Yoon, T. Sekiguchi, T. Sasaki, T. Nakajima, S. Shoji

    The 13th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2018)  (Singapore)  IEEE

    Presentation date: 2018.04

  • 圧電薄膜フィルムを用いた安価な振動発電素子

    笹川健太, 佐々木敏夫, 関口哲志, 中島啓, 庄子習一

    4大学ナノ・マイクロファブリケーションコンソーシアム・シンポジウム 

    Presentation date: 2018.03

  • セルロースナノファイバーゲルを培養場とした多層ファイバー中での筋管形成誘導

    今任景一, 米田憲司, 田中智, 尹棟鉉, 関口哲志, 庄子習一, 武田直也

    第17回日本再生医療学会総会 

    Presentation date: 2018.03

  • Crystallization of Zinc(II) Complex Containing Lysozyme by Super Water Repellent Umbrella Pillar Array

    D. Tanaka, W. Kawakubo, D.H. Yoon, T. Sekiguchi, T. Akitsu, S. Shoji

    CIAiS (Research and Education Consortium for Innovation of Advanced Integrated Science) International Symposium 2018 

    Presentation date: 2018.03

  • Simple Formation of Complex Cross-Sectional Flow Using Multi-Stacked Three-Dimensional PDMS Structures

    D.H. Yoon, T. Sekiguchi, S. Shoji

    CIAiS (Research and Education Consortium for Innovation of Advanced Integrated Science) International Symposium 2018 

    Presentation date: 2018.03

  • マイクロ流体デバイスによる高効率かつ安全なブロモ基付加操作

    川久保渉, 田中大器, 尹棟鉉, 関口哲志, 高橋啓太, 秋津貴城, 庄子習一

    第34回「センサ・マイクロマシンと応用システム」シンポジウム 

    Presentation date: 2017.10

  • 超撥水性二重凹型ピラーアレイデバイスによるZn(II)錯体含有リゾチームの結晶化

    田中大器, 川久保渉, 尹棟鉉, 関口哲志, 秋津貴城, 庄子習一

    第34回「センサ・マイクロマシンと応用システム」シンポジウム 

    Presentation date: 2017.10

  • A Micromachined Liquid Chromatography Chip with a Pillar Array Mixer for Post-Column Derivatization in the Analysis of Neurotransmitters

    M. Isokawa, K. Nakanishi, T. Kanamori, H. Zhuang, H. Yamazaki, T. Sugaya, D.H. Yoon, T. Sekiguchi, T. Funatsu, S. Shoji, M. Tsunoda

    The 21st International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2017) 

    Presentation date: 2017.10

  • Extremely Efficient and Non-Hazardous Bromo Group Addition Reaction Using Simple Microfluidic Devices

    W. Kawakubo, D. Tanaka, D.H. Yoon, T. Sekiguchi, K. Takahashi, T. Akitsu, S. Shoji

    The 3rd Conference on Microfluidic Handling Systems (MFHS 2017) 

    Presentation date: 2017.10

  • CRYSTALLIZATION OF ZINC(II) COMPLEX CONTAINING LYSOZYME BY SUPER WATER REPELLENT DOUBLY REENTRANT STRUCTURE UMBRELLA PILLAR ARRAY

    Tanaka D, Kawakubo W Yoon, D, Sekiguchi T, Akitsu T, Shoji S

    THE 3RD CONFERENCE ON MICROFLUIDIC HANDLING SYSTEMS, 4-6 OCTOBER 2017 

    Presentation date: 2017.10

     View Summary

    This paper reports the crystallization of a functional protein in the droplet on a super water repellent structure that consists of an umbrella-like pillar array. The structure provided certain participation of small volume reagents in the crystallization reaction. The crystallization conditions of functional protein were performed under room temperature and the atmosphere. Furthermore, the open structure allowed simple picking fragile crystals up. The umbrella-like pillar array structure was fabricated by soft MEMS process using SU-8 and polydimethylsiloxane (PDMS) simply. This research proposes a new crystallization technology for functional proteins, and the result of this research is useful for the analysis of functional proteins in the future.

  • Fabrication of the Microfluidic Device for Chemical Reaction

    S. Sawai, D. Tanaka, D.H. Yoon, T. Sekiguchi, T. Akitsu, S. Shoji

    Presentation date: 2017.03

  • FeCo系合金の逆磁歪効果を用いた小型発電素子

    笹川健太, 野崎義人, 関口哲志, 佐々木敏夫, 山浦真一, 中嶋宇史

    4大学ナノ・マイクロファブリケーションコンソーシアム・シンポジウム 

    Presentation date: 2017.03

  • 機能性ファイバー材料合成を目的としたチェック状断面構造層流デバイスの開発

    小林和博, 尹棟鉉, 関口哲志, 庄子習一

    第33回「センサ・マイクロマシンと応用システム」シンポジウム 

    Presentation date: 2016.10

  • 二重四角構造ピラーアレイを応用した超撥水性表面の低コスト量産プロセスの開発

    中西完貴, 簔城森幸, 尹棟鉉, 関口哲志, 庄子習一

    第33回「センサ・マイクロマシンと応用システム」シンポジウム 

    Presentation date: 2016.10

  • Study for Simple Fabrication Process of Printable Piezoelectric Energy Harvest Device

    Presentation date: 2016.10

  • Complex Check-Like Cross-Sectional Flow Formation for Fiber-Shaped Materials

    K. Kobayashi, D.H. Yoon, T. Sekiguchi, S. Shoji

    The 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2016) 

    Presentation date: 2016.10

  • In Vitro Selection of Novel Peptide Agonists for Human Somatostatin Receptor Subtype-2 Using a Water-In-Oil Microdroplet Platform

    T. Sakurai, R. Iizuka, Y. Nakamura, J. Ishii, A. Kondo, A. Iguchi, D.H. Yoon, T. Sekiguchi, S. Shoji, T. Funatsu

    The 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2016) 

    Presentation date: 2016.10

  • Fifty-Second Analysis of Oxidative Stress Markers in Human Plasma Using Amide-Modified Liquid Chromatography Chip

    M. Isokawa, K. Nakanishi, D.H. Yoon, T. Sekiguchi, T. Funatsu, S. Shoji, M. Tsunoda

    The 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2016) 

    Presentation date: 2016.10

  • 早大 MEMS技術の紹介と小型発電デバイスへの応用例

    庄子習一, 関口哲志, 水野潤  [Invited]

    東北大学金属材料研究所・ナノ・ライフ創新研究機構 連携協定締結記念シンポジウム 

    Presentation date: 2016.09

  • インクジェット工法を用いた環境発電素子の作製

    鎌田裕樹, 佐々木敏行, 関口哲志, 庄子習一

    東北大学金属材料研究所・ナノ・ライフ創新研究機構 連携協定締結記念シンポジウム 

    Presentation date: 2016.09

  • Fabrication Process of Fluidic Devices for Producing Fine Droplets

    Y. Nozaki, T. Kanai, A. Matsuo, D. Tanaka, I. Yuito, T. Takeuchi, T. Sekiguchi, S. Shoji

    The 16th International Conference on Nanotechnology, (IEE NANO 2016) 

    Presentation date: 2016.08

  • 脳標本のリアルタイム評価のためのバイオモニタリングシステムの開発

    根岸周也, 鎌田将仁, 梶原利一, 金子祐史, 尹棟鉉, 関口哲志, 庄子習一, 工藤寛之

    電気学会センサ・マイクロマシン部門総合研究会 

    Presentation date: 2016.06

  • 三次元マイクロ流体デバイスを用いたマルチコア螺旋構造ファイバの作製

    尹棟鉉, 有吉理沙, 佐藤成晃, 関口哲志, 庄子習一

    電気学会センサ・マイクロマシン部門総合研究会 

    Presentation date: 2016.06

  • Development of a Simple Fabrication Process for a Printable Piezoelectric Energy Harvest Device

    Y. Kamata, D.H. Yoon, T. Sasaki, Y. Nozaki, S. Yamaura, T. Sekiguchi, T. Nakajima, S. Shoji

    The 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2016) 

    Presentation date: 2016.04

  • All-Round Micro Sheath Flow Formation to Realize Complex Cross Sections by Simply Stacked PDMS Structures

    D.H. Yoon, L. Ariyoshi, D. Tanaka, T. Sekiguchi, S. Shoji

    The 29th IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2016) 

    Presentation date: 2016.01

  • マイクロフルイディックエンジニアリングの進展と課題

    庄子習一, 尹棟鉉, 関口哲志  [Invited]

    新化学技術推進協会(JACI) 電子情報技術部会 マイクロナノシステムと材料・加工分科会 講演会 

    Presentation date: 2015.11

  • チップストリーミングを用いた単一細胞解析に向けた分離可能な液滴の生成

    鎌田祐樹, 尹棟鉉, 関口哲志, 庄子習一

    第32回「センサ・マイクロマシンと応用システム」シンポジウム 

    Presentation date: 2015.10

  • 外部磁場で制御可能な回転式マイクロアクチュエータの作製とマイクロ液滴搬送への応用

    中西完貴, 尹棟鉉, 関口哲志, 庄子習一

    第32回「センサ・マイクロマシンと応用システム」シンポジウム 

    Presentation date: 2015.10

  • On-Chip Integration of Solid-Phase-Extraction and Silicon Pillar Arrays for High Efficient Liquid Chromatography

    K Nakanishi, K. Shih, T. Kanamori, D.H. Yoon, T. Funatsu, M. Tsunoda, T. Sekiguchi, S. Shoji

    The 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2015) 

    Presentation date: 2015.10

  • Culture-Independent Method for Screening and Identifying Microbial Enzyme-Encoding Genes Using Microdroplet-Based Single Cell Genomics

    K. Nakamura, R. Iizuka, T. Yoshida, Y. Hatada, Y. Takaki, S. Nishi, A. Iguchi, D.H. Yoon, T. Sekiguchi, S. Shoji, T. Funatsu

    The 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2015) 

    Presentation date: 2015.10

  • Multi-Stage Size Dependent Passive Droplet Sorting Using Droplet Transfer on Cascade Line-Rails and Shape Recovery on Dot-Rails

    Z. Xie, D.H. Yoon, T. Sekiguchi, S. Shoji

    The 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2015) 

    Presentation date: 2015.10

  • Single Cell Encapsulated Microdroplet Formation Using TIP-Streaming and Deterministic Lateral Displacement

    Y. Kamata, D.H. Yoon, T. Sekiguchi, S. Shoji

    he 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2015) 

    Presentation date: 2015.10

  • High Efficient Synthesis of Manganese(II), Cobalt(II) Complexes Containing Lysozyme Using Reaction Area Separated Micro Fluidic Device

    D. Tanaka, Y. Murakoshi, E. Tsuda, Y. Mitsumoto, D.H. Yoon, T. Sekiguchi, T. Akitsu, S. Shoji

    The 18th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2015) 

    Presentation date: 2015.06

  • In Situ Monitoring Chemical Reaction in Microdroplet

    T. Fukuda, T. Kurabayashi, H. Udaka, D.H. Yoon, M. Suzuki, A. Nakahara, T. Sekiguchi, S. Shoji

    EMN (Energy Materials Nanotechnology) Meeting on Droplets 

    Presentation date: 2015.05

  • Development of fluorescence-activated droplet sorting system using thermoreversible gelation polymer and its application

    Presentation date: 2014.09

  • Peptide-based ligand screening system for G protein-coupled receptors (GPCRs) using water-in-oil microdroplets

    Presentation date: 2014.09

  • 量子ドット‐色素間の反応速度に微小液滴のサイズが与える影響

    応用物理学会 

    Presentation date: 2014.09

  • High Yield Micro Fluidic Synthesis of Metal Complex Containing Proteins

    The 6th International Symposium on Microchemistry and Microsystems Grand Copthorne Waterfront Hotel Level 2, Waterfront Ballroom 

    Presentation date: 2014.07

  • real time monitoring of chemical reaction in micro droplet with quantum dot and dye using Fluorescence spectroscopy

    The 8th International Symposium on Organic Molecular Electronics 

    Presentation date: 2014.05

  • Three-Dimensional Sample Flow Focusing for Wide Range Flow Speed Applications

    STAC5/AMDI2 

    Presentation date: 2011.06

  • EHD MICRO PUMP USING PYROLYZED POLYMER 3-D CARBON MESH ELECTRODES

    IEEE MEMS 2009 

    Presentation date: 2009.01

  • COMPARISON OF A MICROFLUIDIC GAS-INTAKE DEVICES WITH PILLAR-TYPE AND MICROFLUIDIC MEMBRANE-TYPE STRUCTURES

    prime2008(ECS 214th) hawaii October 12-17, 2008 

    Presentation date: 2008.10

  • LCチップ集積に向けたポストカラムミキサーの開発

    菅谷拓央, 中西完貴, 磯川宗生, 尹棟鉉, 関口哲志, 庄子習一, 船津高志, 角田誠

    4大学ナノ・マイクロファブリケーションコンソーシアム・シンポジウム 

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Syllabus

  • MEMS

    Graduate School of Advanced Science and Engineering

    2022   spring semester

  • MEMS

    School of Fundamental Science and Engineering

    2022   spring semester

  • MEMS

    Graduate School of Fundamental Science and Engineering

    2022   spring semester