Papers - Taguchi, Yoshihiro

Diffusion Coefficients of Surface Modified Liposomes and Thermo-sensitive Liposomes Measured by Optoelectronically Induced Transient Grating Method

Kamata M., Shishido R., Oura M., Kojima I., Taguchi Y.

International Journal of Thermophysics 46 ( 11 )  2025.11

ISSN  0195928X

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Liposomal products enable new therapies through the protection and controlled release of encapsulated medicines. The diffusion coefficient of a liposome is associated with its size and surface properties, and its measurement is important in the evaluation of the product and design of new drug delivery systems. We propose a rapid and label-free diffusion sensing method using light-induced dielectrophoresis for high-throughput analysis of liposomal products. In this study, the diffusion coefficient of liposomes with a diameter of approximately 100 nm was measured by observing the mutual diffusion within a few seconds. Prior to the measurement, a parametric study of the excitation conditions was performed to achieve highly efficient manipulation of liposomes by light-induced dielectrophoresis. The validation of the proposed measurement method for liposomes was demonstrated by comparing the result of observation by the transmission electron microscope. The effect of the surface functional groups of the liposomes was quantitatively evaluated using diffusion coefficient measurements. Furthermore, the thermo-sensitive liposomes were measured to demonstrate their sensitivity to phase transition during temperature change.

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Flexible and Broadband Long-Wavelength Infrared Radiator Based on a Pixel Pattern Metamaterial for Space Cryogenic Applications

Saisho Y., Tachikawa S., Sakurai A., Taguchi Y.

International Journal of Thermophysics 46 ( 8 )  2025.08

ISSN  0195928X

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This study proposes the design of an ultra-far-infrared broadband metamaterial radiator for space cryogenic applications. To achieve a flexible broadband radiator without significant structural complexity, the proposed radiator employs a flexible glass sheet as an intermediate dielectric layer and a QR code-like pixel-patterned periodic metal structure. A genetic algorithm is used to design the radiator, followed by fabrication using microfabrication techniques. The results of the reflectance spectrum measurements by FTIR were in general agreement with the analytical results, thereby confirming the broadband radiation characteristics. The total hemispherical emittance, which is an evaluation index for space radiators, was estimated to be 0.57 at 20 K. Compared with the conventional radiator material of 80-μm black paint, the total hemispherical emittance was markedly enhanced, despite a film thickness ratio of 19.9 % and an area density ratio of 53.7 %. Therefore, the proposed radiator is expected to facilitate the development of cryogenic radiators with reduced weight and flexibility while minimizing the risk of contamination. This is a significant consideration for infrared astronomy missions that require cryogenic temperatures.

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Quadrant kirigami-type electrothermal MEMS actuator with multi-degree-of-freedom morphing capability

Tsutsui T., Taguchi Y., Hashimoto M.

Journal of Micromechanics and Microengineering 35 ( 2 )  2025.02

ISSN  09601317

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Kirigami design principles have been widely applied to develop thermally responsive shape-morphing devices across various scales. However, the multi-degree-of-freedom (multi-DoF) morphing capabilities of microelectromechanical-systems (MEMS)-scale kirigami devices under localized Joule heating remain largely unexplored. This paper presents a quadrant kirigami-type electrothermal MEMS actuator with multi-DoF morphing capabilities, demonstrating both one-dimensional piston motion and two-dimensional (2D) tilting motion. The actuator, fabricated using surface and bulk micromachining techniques, features four independent electrical circuits, creating four electrothermally separated quadrants within the MEMS-scale kirigami structure. The temperature distribution within each quadrant of the actuator, subjected to localized Joule heating, was experimentally examined using thermography, revealing distinct temperature contrasts. The actuator demonstrated multi-DoF morphing capabilities, achieving a 2D tilting angular displacement of approximately 10° at 70 mW and a vertical piston displacement of 1.5 mm at 135 mW. These experimental results validate that the electrothermal quadrant design, leveraging localized Joule heating, enhances the DoF morphing capabilities of kirigami-type electrothermal MEMS actuators.

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Multi-Photon 3D Bioprinting of Scaffold Structures for Blood Vessel Formation Using Femtosecond Laser

Suda M., Ono A., Sudo R., Taguchi Y.

International Conference on Optical MEMS and Nanophotonics  2025

ISSN  21605033

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This study presents a method for applying multi-photon absorption to fabricate micro-scale scaffold structures for blood vessel formation within hydrogels, using a femtosecond laser. The structures were fabricated via femtosecond laser ablation and cavitation enabling the replication of complex micro-scale microvascular systems. A pressure control system was designed to reproduce variations in channel diameter observed in natural blood vessels. By adjusting the pressure, changes in diameter were confirmed demonstrating the influence of pressure on cavitation. Fabricated structures using the two modes were also evaluated by seeding endothelial cells and subsequent blood vessel formation was observed.

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Multi-material 3D Microprinting in Resin Droplets Using Two-photon Polymerization

Li T., Taguchi Y.

International Conference on Optical MEMS and Nanophotonics  2025

ISSN  21605033

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Polyethylene glycol diacrylate (PEGDA) is a photosensitive polymer offering self-healing capabilities through chemical or structural modifications, making it suitable for enhancing the reliability of micro/nano robotics. This study introduces a 3D microdroplet printing approach using direct laser writing (DLW) via two-photon polymerization with a femtosecond laser. Adding DI water can reduce the viscosity of PEGDA, and the nL droplets with T-junction can be created. On the basis, some kinds of metal powder can be added into PEGDA to make composite resin droplets. And I can also do 3D printing by using the different composite resin to create a multilayer structure of hundreds of microns. This work demonstrates a novel method for precise microdroplet-based 3D fabrication, advancing micro/nano manufacturing technologies.

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Direct writing of graphitic carbon/polydimethylsiloxane bimorph thermal microactuator via two-photon polymerization and laser-induced graphitization

Yu Yamashita, Yasuko Tanaka, Chen Tianzhou, Yoshihiro Taguchi, and Masaaki Hashimoto

Mechanical Engineering Journal  2024

Accepted

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(Accepted)

2光子マイクロ光造形とフェムト秒レーザアブレーションを用いた熱駆動ソフトマイクロアクチュエータ作製の基礎検討

陳天州, 田口良広, 橋本将明

熱物性  2024

Accepted

Bimorph Thermal Microactuator Fabricated by Additive and Subtractive Femtosecond Laser Processing

Chen T., Taguchi Y., Hashimoto M.

International Conference on Optical MEMS and Nanophotonics  2024

ISSN  21605033

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This study presents an additive and subtractive fabrication method for a bimorph thermal microactuator using TPP 3D printing and femtosecond laser ablation. First, a microcantilever with a thickness of 30 μm was printed by TPP 3D printing. Second, femtosecond laser ablation was utilized to reduce the thickness to 15 μm, which facilitated the creation of a bimorph structure. The cantilever-shaped bimorph microactuator demonstrated stable cyclic actuation, achieving a tip displacement of 11.5 μm through laser heating.

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Design of focus-tunable freeform microlens printed on kirigami MEMS actuator

Matsuoka Y., Tsutsui T., Taguchi Y., Hahsimoto M.

International Conference on Optical MEMS and Nanophotonics  2024

ISSN  21605033

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This study proposes the design of a focus-tunable freeform microlens printed on a MEMS actuator. The proposed freeform microlens, designed with its varying surface curvature along the azimuthal direction, can adjust its focal length through the tilt motion of the MEMS actuator. The designed freeform microlens was printed onto a glass substrate, and demonstrated focus tunability ranging from 0.31 mm to 3.72 mm.

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Fabrication and characterization of VO<inf>2</inf> kirigami electrothermal MEMS actuator

Tsutsui T., Taguchi Y., Hashimoto M.

International Conference on Optical MEMS and Nanophotonics  2024

ISSN  21605033

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A kirigami electrothermal MEMS actuator using the phase transition material VO2 has been proposed. This paper reports the fabrication process and mechanical characteristics of the actuator. The actuator was fabricated by MEMS processes with VO2 annealing method. Through the environmental heating, the actuator exhibited the bi-directional actuation due to the thermal expansion and phase transition shrinkage of VO2, resulting in a net downward displacement of 219.5 μm.

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Fabrication of a Soft Photothermal Microactuator Using Two-photon Polymerization and Vacuum Filling

Tanaka K., Taguchi Y., Hashimoto M.

International Conference on Optical MEMS and Nanophotonics  2024

ISSN  21605033

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A fabrication method of a soft photothermal microactuator using two-photon polymerization and vacuum filling is proposed. Proposed microactuator was fabricated through two processes: A two-photon polymerization (TPP) and a composite injection by a vacuum filling. First, a PDMS microcantilever with a microfluidic channel was printed by TPP. Second, a PDMS composite containing thermally expandable microspheres was filled in the microfluidic channel. To validate this method, a microactuator with dimensions of 1 mm × 130 μm × 100 μm was fabricated. We demonstrated the ability of the soft photothermal microactuator to produce displacement of approximately 50 μm by laser heating.

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Additive manufacturing method of electrothermal 4D bimorph microactuator

Masaaki Hashimoto, Takaya Sato, Yoshihiro Taguchi,

Sensors and Actuators: A. Physical  356 ( 114348 )  2023.06

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted,  ISSN  09244247

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This paper presents an additive manufacturing method of an electrothermally controllable 4D-printed bimorph microactuator. We fabricated an electrothermal 4D bimorph microactuator equipped with an electrical heater through a two-step additive process: two-photon polymerization (TPP) 4D printing and liquid metal microfluidic injection. First, a 3D thermal bimorph microstructure including a microchannel was built using TPP printing. Second, the printed microstructure was electrically wired by injecting a liquid metal into the microchannel. To validate this method, we fabricated and characterized a vertical-spiral-shaped electrothermal 4D rotary microactuator with a large angular displacement. The fabricated electrothermal microactuator successfully controlled its temperature and angular displacement via electricity. Furthermore, we experimentally demonstrated the unique ability of the electrothermal 4D bimorph microactuator to produce repeatable large angular displacements of more than 10° at 386 mV. Accordingly, the proposed method is expected to enhance the spatial design freedom of electrothermal microactuators with potential applications in soft microrobotics.

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Design of Bi-Directional VO<inf>2</inf>-Kirigami Electrothermal Microactuator with Millimeter Large Stroke

Hashimoto M., Tsutsui T., Taguchi Y.

2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems, Transducers 2023    741 - 744 2023

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This paper reports the design of a bi-directional VO2-KIRIGAMI electromechanical microactuator with a large millimeter stroke and low power consumption. Using Finite Element Method (FEM) simulation, it has been demonstrated that the proposed VO2-KIRIGAMI design can achieve a remarkable stroke of 2.2 mm with a power consumption of only 54 mW. This design study has enabled the application of electrothermal microactuators in long-range lens focusing for endoscopic procedures.

Development of a Millimeter-Stroke Electrothermal Kirigami MEMS Actuator with Low Driving Power -Static and Dynamic Thermomechanical Characteristic of Film Bimorph-

Masaaki Hashimoto, Yoshihiro Taguchi

Netsu Bussei 34 ( 4 ) 109 - 116 2020.07

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted

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Circular pyramidal kirigami microscanner with millimeter-range low-power lens drive

Hashimoto M., Taguchi Y.

Optics Express (Optics Express)  28 ( 12 ) 17457 - 17467 2020.06

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© 2020 Optical Society of America under. This paper proposes an electrothermally-actuated circular pyramidal kirigami microscanner with a millimeter-range low-power lens drive for endoscopic biomedical applications. A variation of Japanese origami art, kirigami involves creation of out-of-plane structures by paper cutting and folding. The proposed microscanner is composed of freestanding kirigami film on which the spiral-curved thermal bimorphs are strategically placed. The kirigami microscanner is electrothermally transformed into an out-of-plane circular multistep pyramid by Joule heating. The circular pyramidal kirigami microscanner on a small footprint of 4.5 mm 4.5 mm was fabricated by microelectromechanical system processes. A large four-step pyramidal actuation was successfully demonstrated, and a large 1.1-mm lens travel range at only 128 mW was achieved.

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Design and fabrication of a kirigami-inspired electrothermal MEMS scanner with large displacement

Hashimoto M., Taguchi Y.

Micromachines (Micromachines)  11 ( 4 )  2020.04

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© 2020 by the authors. Large-displacement microelectromechanical system (MEMS) scanners are in high demand for a wide variety of optical applications. Kirigami, a traditional Japanese art of paper cutting and folding, is a promising engineering method for creating out-of-plane structures. This paper explores the feasibility and potential of a kirigami-inspired electrothermal MEMS scanner, which achieves large vertical displacement by out-of-plane film actuation. The proposed scanner is composed of film materials suitable for electrothermal self-reconfigurable folding and unfolding, and microscale film cuttings are strategically placed to generate large displacement. The freestanding electrothermal kirigami film with a 2 mm diameter and high fill factor is completely fabricated by careful stress control in the MEMS process. A 200 μm vertical displacement with 131 mW and a 20 Hz responsive frequency is experimentally demonstrated as a unique function of electrothermal kirigami film. The proposed design, fabrication process, and experimental test validate the proposed scanner's feasibility and potential for large-displacement scanning with a high fill factor.

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Development of a robust autofluorescence lifetime sensing method for use in an endoscopic application

Ito S., Hashimoto M., Taguchi Y.

Sensors (Switzerland) (Sensors (Switzerland))  20 ( 7 )  2020.04

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© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Endoscopic autofluorescence lifetime imaging is a promising technique for making quantitative and non-invasive diagnoses of abnormal tissue. However, motion artifacts caused by vibration in the direction perpendicular to the tissue surface in a body makes clinical diagnosis difficult. Thus, this paper proposes a robust autofluorescence lifetime sensing technique with a lens tracking system based on a laser beam spot analysis. Our optical setup can be easily mounted on the head of an endoscope. The variation in distance between the optical system and the target surface is tracked by the change in the spot size of the laser beam captured by the camera, and the lens actuator is feedback-controlled to suppress motion artifacts. The experimental results show that, when using a lens tracking system, the standard deviation of fluorescence lifetime is dramatically reduced. Furthermore, the validity of the proposed method is experimentally confirmed by using a bio-mimicking phantom that replicates the shape, optical parameters, and chemical component distribution of the cancerous tissue.

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Nanoparticle sorting technique using laser induced dielectrophoresis with phase modulated interference

Miura D., Taguchi Y., Nagasaka Y.

International Conference on Optical MEMS and Nanophotonics (International Conference on Optical MEMS and Nanophotonics)  2019-July   100 - 101 2019.07

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© 2019 IEEE. A novel nanoparticle sorting technique using the laser-induced dielectrophoresis (LIDEP) and phase modulated interference has been developed. In this paper, a proposed method of nanoparticle sorting and fabrication of microfluidic device are reported, and the validity of a method is discussed.

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Kirigami-inspired Electrothermal Actuator for Motion Tracking Blood Flow Measurement

Hashimoto M., Taguchi Y.

International Conference on Optical MEMS and Nanophotonics (International Conference on Optical MEMS and Nanophotonics)  2019-July   152 - 153 2019.07

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© 2019 IEEE. A large stroke electrothermal MEMS actuator with small device footprint and low driving voltage has been proposed for motion tracking blood flow measurement. This paper reports this kirigami-inspired device design and simulation results of the proposed actuator.

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Rapid and label-free sensing of intermolecular interactions using compact optical diffusion sensor

Kamata M., Takaba Y., Taguchi Y., Nagasaka Y.

International Journal of Heat and Mass Transfer (International Journal of Heat and Mass Transfer)  133   73 - 79 2019.04

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© 2018 The Authors Diffusion sensors for nano-sized materials dispersed in a solution are promising tools for investigating intermolecular interactions, which is an important task in a wide range of industrial and biomedical fields, such as the development of therapeutic products and diagnostic tools. For the development of the sensor applicable to point-of-care testing, an optofluidic sensor was proposed. The proposed sensor realizes a simple measurement in a short time using microscale manipulation by interferometrically-induced dielectrophoresis and optical detection. In this paper, the applicability of the proposed sensor to distinguish nanoscale differences in size was confirmed by measurements on a solution containing size-certified plain nano-beads (51 nm, 100 nm, 203 nm, 216 nm and 240 nm) with evaluating the uncertainties of the proposed sensor. Furthermore, measurements using 200-nm beads coated with functional groups (NH2 and biotin) and proteins (streptavidin and bovine serum albumin) demonstrated the applicability to the investigation of intermolecular interactions.

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