Evaluation of Permeability of Thermoresponsive Microgel Valves for Single-Cell Analysis Devices*

In recent years, microfluidic devices have attracted large attention as a tool for single-cell analysis. Among the components of microfluidic devices, valves are important for fluid control in devices. Our group have proposed on-chip microvalves made of a thermoresponsive hydrogel that can be actuated by using light irradiation. By using the light irradiation for actuation, we can integrate a large number of microvalves and drive them independently without complex wirings. This integrated microvalve can be used for single cell manipulations for analyses, such as trap, transport, mechanical stimulation or chemical stimulation. In this study, we evaluate permeability of some chemical reagents to the hydrogel valves to confirm possibility of application of the valves for chemical stimuli. We varied sizes of microgel valves and molecular weight of chemicals and evaluate permeation time for the design of gel valves that are suitable for single-cell analysis.