International Research Network

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Title 1. Massive integrated on-chip gel actuator for single cell manipulations
Speaker: Prof. Takeshi Hayakawa, Faculty of Science and Engineering, Chuo University
Date: 2023/12/04(Mon.) 
Abstract
     Single cell manipulation is important technique to realize various single cell analyses. Especially, single cell manipulations on a microfluidic chip enables highthroughput, high-content and low cost single cell analyses. To realize various single cell manipulations on a microfluidic chip, on-chip actuators are essential components. We proposed light-driven on-chip hydrogel actuator made of themoresponsive hydrogels. The actuators are patterned with light absorber to control its temperature. By irradiating an actuator with light, we can increase temperature of the actuator and actuator it. Thus, the proposed actuator can be driven without any wiring. The proposed actuator can be fabricated with size of 10 um order by using photolithography. Thus, larger number of actuator can be integrated in a microfluidic chip and independently driven. The proposed actuator will contribute to high-throughput parallel processing of single cell analysis on a chip.

BiographyProf. Takeshi Hayakawa
Takeshi Hayakawa received the B.S. and M.S. degree from the the Department of Physics, Tokyo University of Science, Tokyo, Japan, in 2009 and the Ph.D. degree from Nagoya University, Nagoya, Japan, in 2015. He became an Associate Professor with Nagoya University in 2015. He became an Assistant Professor with the Department of Precision Mechanics of Chuo University, Japan in 2017 and promoted to Associate Professor. His research interests are micro/nanorotobics, microfluidics, and MicroTAS

Title 2. Nanoscopic design of molecular delivery using “nanoparticles based on lipids”
Speaker: Prof. Niko Kimura, Division of Advanced Mechanical Systems Engineering, Institute of Engineering, Tokyo University
Abstract
      Recent years have witnessed dramatical progress in development of novel nanometer sized pharmaceuticals using nanoparticles based on lipids (LNPs). LNPs are biocompatible nanocarriers for delivering biomolecules and functional nanomaterials into live-cells. Up to the present time, we constructed microfluidic methods for LNP production having desired physical characteristics. In the microfluidic methods, we can obtain LNPs by just introducing two types of solutions: lipids dissolved ethanol solution and aqueous solution. In the micro-meter scaled channel, due to the low Reynolds number, a stable liquid–liquid interface between lipophilic phase and aqueous phase are formed and allows homogeneous self-assembling. Hence, we can obtain desired LNPs by controlled self-assembly. Use of designed LNPs helped to clarify the extent of the impact of the tunable physical characteristics that are inseparably related to each other, on transportation, and as a result provide a bidirectional guidepost for streamlined design and understanding of the biofunctions of LNPs. In addition, designed LNPs allowed to construct a novel concept of “Avatar cell” and visualize designed cell-cell communication and spatial controlled delivery.

BiographyProf. Niko Kimura
• Doctor of Philosophy in Engineering, (March 15, 2021) Graduate School of Chemical Sciences and Engineering, Hokkaido University, Japan
• Assistant Professor, (April 1, 2021–August 31, 2023) Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Japan
• Senior Assistant Professor, (September 1, 2023–) Division of Advanced Mechanical Systems Engineering, Institute of Engineering, Tokyo University of Agriculture and Technology, Japan

Title 3. LCI-S and TDCSS, the pioneering tools to reveal cellular secretory responses
Speaker: Prof. Yoshitaka Shirasaki, Research Center for Advanced Science and Technology, The University of Tokyo
Abstract
      Intercellular communication, which is essential for maintaining the complex harmony of living systems, is mediated by humoral factors. A crucial issue in this field concerns the diversity at the single-cell level in both the population and timing of humoral factor production. Conventional bulk assays have difficulty tackling this complex challenge, and advanced techniques with high spatiotemporal resolution are needed to characterize the secretion activity of individual cells. To address this challenge, we have developed Live Cell Imaging of Secretion Activity (LCI-S), which facilitates real-time visualization of dynamic cellular activity associated with the release of humoral factors by using a wash-free Fluorospot assay on a total reflection fluorescence microscope. LCI-S has been successfully demonstrated to visualize the production of IL-1 in regulated cell death processes such as pyroptosis and necroptosis. LCI-S also revealed how the secretion activity of group 2 innate lymphocytes (ILC2), which is critical for the initiation of type 2 immune responses, is initiated. Furthermore, combined with comprehensive gene expression analysis by time-dependent cell state selection (TDCSS), LCI-S revealed significant changes in gene expression patterns as ILC2 undergoes a transition to the active state.

BiographyProf. Yoshitaka Shirasaki
Education: Ph.D. degree in bioscience and biotechnology, graduate school of science and engineering, Waseda University, Japan.
Research Achievements: On-chip sorter of thermo-sensitive hydrogels by laser heating manipulation. Live cell imaging of secretory response and gene expression analysis, and its application research and commercialization.

Title 4. On-chip continuous particle/cell separation through micropillar arrays
Speaker: Prof. Naotomo Tottori, Department of Mechanical Engineering, Kyushu University
Abstract
      Separation and purification of target particles from a heterogeneous population in a suspension is an essential step for the sample preparation for biological and chemical analysis. Presently, microfluidic techniques for particle separation have been attracting attention because of their advantages of minimizing the processed sample volume as well as ease of integration with other elements for comprehensive analysis. As one of the promising passive separation techniques, deterministic lateral displacement (DLD) has been extensively studied because of the advantage of continuous separation of various-sized particles (e.g. from nanometer to millimeter) based on their effective sizes at high resolution through the micropillar arrays. In this presentation, I introduce my recent research topics related to microfluidic devices for particle/cell separation through DLD micropillar arrays.

BiographyProf. Naotomo Tottori
      Naotomo Tottori received Dr. Eng. in mechanical engineering from Tokyo Institute of Technology in 2018. Presently, he is an assistant professor working in Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, Japan. His current research interest mainly includes microfluidic particle separation and droplet microfluidic systems.

Title 5. Programmable DNA–metal hybrid structures with the ability of interacting with biomolecules
Speaker: Prof. Maasa Yokomori, Department of Mechanical Engineering, Kyushu University
Abstract
      Nucleic acids, which are essential biomolecules with genetic information, can also provide a powerful and flexible path towards self-assembly of nanomaterials with designed structure and functionalities. In particular, DNA-based structures that can encapsulate nanoscale molecules, such as proteins, have great potentials in various applications including drug carriers and reaction fields. However, DNA-based structures have problems with their rigidity and stability under dry conditions, which limits their applications. In this talk, I will present my recent work on developing a new type of DNA-metal hybrid structures for macromolecular encapsulation. DNAfunctionalization enables to fabricate porous colloidal crystals by controlling the distance between nanoparticles and their spatial arrangement in a precise manner. Proteins such as genome editing enzyme, CRISPR/Cas9 RNP, were successfully encapsulated into the gold colloidal crystals by harnessing the hollow spaces in the crystal lattices and their affinities for the target molecules. The potential use of DNAmetal hybrid crystals as the carriers for direct protein delivery into plant cells with hard cell walls via biolistic bombardment was also demonstrated. The affinity with biomolecules, rigidity, structural regularity, and optical properties of the crystals are expected to be utilized for carriers in drug delivery systems, biosensors, and the creation of new materials.

BiographyProf. Maasa Yokomor
      Maasa Yokomori received her Ph.D. degree from the Graduate School of Arts and Sciences, the University of Tokyo in 2018. She joined Institute of Materials and Systems for Sustainability, Nagoya University in 2019 as postdoctoral research fellow. Since 2023, she is an assistant professor of Department of Mechanical Engineering, Kyushu University. Her research interests include DNA nanotechnology, selfassembled functional DNA materials, biohybrid nanoarchitectures and bioanalysis.

Title 6. Cell manipulation with high-speed & high-resolution based on "flow reduction mechanisms"

Smart Materials, Adaptive Structures and Intelligent Systems

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