Research projects

Synthesis of copper nanoparticles using microfluidic device
 Copper nanoparticles (CuNPs) are attracting attention as ink materials with lower cost than silver and excellent in performance such as electrical conductivity. However, since copper is easily oxidized, synthesis in an inert atmosphere is necessary, and the particle size depends on the reduction temperature. It is expected that since the microfluidic device is sealed from the outside and the thermal efficiency is high, it is possible to control the particle size of CuNPs by changing the temperature and the flow rate in the microchannel.

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  1. Yiyang Liang, Yoko Shinozaki, Hiromasa Yagyu: "Synthesis of Copper Nanoparticles using Glass Microfluidic Device", Proceedings of the Eurosensors XXXII, Graz, Austria (September, 2018), pp.1110-1114.

Synthesis of gold nanoparticles dispersion in organic solvent using microfluidic device
 In the Brust-Siffrin method (Brust method), an immiscible solution consisting of an aqueous solution and a toluene solution is vigorously stirred in the presence of a protective agent after an aqueous gold ion solution is transferred to a toluene phase (organic phase) using a phase transfer catalyst, and then gold nanoparticles dispersion in toluene can be synthesized by adding an reducing agent solution. In the case of synthesizing nanoparticles by Brust method using a beaker, since the particle size depends on the addition rate of the reducing agent, the stirring speed, and the stirring time, it is difficult to control particle size. Since the flow state of immiscible solution in the microchannel depends on the flow rate, the particle size of the synthesized nanoparticles by adjusting the flow rate. In this study, we investigated the visualization of the flow state of the immiscible solution in the microchannel, and the relation of the flow rate and the coefficient of variation (standard deviation / mean diameter) was clarified.

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  1. Mao Hamamoto,Yiyang Liang, Hiromasa Yagyu: "Synthesis of Gold Nanoparticles Dispersion in Organic Solvent using Immiscible Fluid Flow in Microfluidics", IEEJ Transactions on Sensors and Micromachines (in Japanese) Vol. 139 No. 5, (2019), accepted.
  2. Mao Hamamoto, Yiyang Liang, Hiromasa Yagyu: "Size Control of Gold Nanoparticles in Organic Solvent using Immiscible Fluid Flow in Glass Microfluidics", Proceedings of the 22nd International Conferrence on Miniaturized Systems for Chemistry and Life Sciences (µTAS 2018), Kaohsiung, Taiwan (11-15 November, 2018), pp.2175-2177.
  3. Mao Hamamoto, Hiromasa Yagyu: "Two-Phase Brust-Schiffrin Synthesis of Gold Nanoparticles Dispersion in Organic Solvent on Glass Microfluidic Device", The 17th IEEE International Conference on Nanotechnology (IEEE NANO 2017), Pittsburgh (July 25-28, 2017), pp.632-635.

DNA nanostructure
 The double stranded DNA model was created for production of DNA nanostructure applied DNA origami technology. The model with electrostatic interaction was discussed. We confirmed that the dependency of the salt concentration on the persistence length of the nCG-dsDNA model at the 30% charge is in good agreement with the Poisson–Boltzmann theoretical model.


  1. Hiromasa Yagyu, Do-Nyun Kim, Osamu Tabata: Proceedings of the 11th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2016), Matsushima and Sendai (April, 2016), B3P-B-6.
  2. Hiromasa Yagyu, Jae-Young Lee, Do-Nyun Kim, Osamu Tabata: The Journal of Physical Chemistry B (American Chemical Society) , Vol. 121 Issue 19, p.5033-5039 (2017).

Laser microfabrication process
 Laser microfabrication of goid nanoparticles dispersed polymer film is prposed. Since wave length of laser beam is selected an absorption wavelength by plasmon resonance vibration of gold nanoparticles, the polymer film can be micromachined. In this study, we focus the effect of size and distribution of naoparticle on laser processed shape.

  1. H. Yagyu, O. Tabata: Applied Surface Science, Vol.255 No. 5 Part 1, p.2237-2243 (2008).
  2. T. Kikitsu, Y. Yagoto, M. Ogawa, H. Yagyu: The 18th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers2015), Anchorage (June, 2015), pp.1881-1884.
  3. H. Yagyu, T. Kikitsu: Journal of Micromechanics and Microengineering, Vol. 25 No. 12, 125018(7pp) (2015).

Analysis of gold nanoparticles synthesis mechanism using microfluidic device
 A glass microfluidic device with mcirochannel is fabricated by micropowder blasting, and the prepareation of metalic nanoparticles on the produced device is prposed. In this study, we focus the production of device which can synthesize nanoparticles by liquid-phase reduction method.


  1. 濱村心, 森塚大樹, 柳生裕聖: 日本機械学会 第6回マイクロ・ナノ工学シンポジウム講演論文集, 松江(2014年10月), 20pm3-PM021.
  2. Yu Tanabe, Hiromasa Yagyu: Proceedings of SPIE Vol. 10061, 1006119 (2017).
  3. Yu Tanabe, Keisuke Yamauchi, Mao Hamamoto, Hiromasa Yagyu: International Symposium on Micro-Nano Science and Technology 2016, Tokyo (Dec. 16-18, 2016), p.124.
  4. Hiromasa Yagyu, Yu Tanabe, Satoru Takano, Mao Hamamoto: Micro & Nano Letters (The Institution of Engineering and Technology) , accepted.
  5. Mao Hamamoto, Hiromasa Yagyu: the 17th IEEE International Conference on Nanotechnology (IEEE NANO 2017), Pittsburgh (July, 2017), accepted.

Simulation of polymer resist for MEMS
 The mechanical property of the polymer resist is required for development of MEMS microfluidic device. We predict the relationship between the mechanical property and the structure of resist in molecular scale by coarse grained molecular dynamics simulation.

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  1. H. Yagyu, Y. Hirai, A. Uesugi, Y. Makino, K. Sugano, T. Tsuchiya, O. Tabata: Polymer, Vol.53, p.4834-4842 (2012).
  2. 平井義和, 柳生裕聖, 牧野圭秀, 上杉晃生, 菅野公二, 土屋智由, 田畑修: 電気学会論文誌E(センサ・マイクロマシン部門誌), Vol.133 No.9, p.320-329 (2013).

Simulation of rubber materials
 A polymer chain is treated as a simple beads-spring model, and the viscoelastic and elongation behavier of the model is simulated using molecular dynamics calculation software such as OCTA/COGNAC and LAMMPS with supercomputer according to the model scale.

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  1. H. Yagyu, T. Utsumi: Computational Materials Science, Vol.46 Issue 2, p.286-292 (2009).
  2. 柳生裕聖: 日本機械学会論文集(計算力学), Vol.80 No.810, p.CM0032 (2014).
  3. H. Yagyu: Soft Materials, Vol.13 Issue 4, p.263-270 (2015).

Simulation of micropowder blasting
 We predict processed shape on a glass substrate by powder btasting using cellular automaton method. The simulator is improved by comparison of experimental result and simulated result, in addition of the production of processing system.

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  1. H. Yagyu, O. Tabata: Journal of Micromechanics and Microengineering, Vol.18 No. 5, 055010(9pp) (2009).
  2. H. Yagyu, O. Tabata: Transaction on Electrical and Electronic Engineering, Vol.2 No. 3, p.348-356 (2007).

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Last-modified: 2023-02-01 (水) 00:31:14 (58d)