Development of a micro optical diffusion sensor using laser-induced dielectrophoretic manipulation

Department of System Design Engineering, Keio University, Japan We have developed a novel micro optical diffusion sensor (MODS) based on laser-induced dielectrophoresis (LIDEP), which enables rapid measurement with a small sample volume and on-site sensing of protein conformation. This paper presents the measurement principle, the chip design, and the validity of the proposed method. To verify the applicability of MODS, we confirmed a sinusoidal concentration distribution of polystyrene beads in a surface-modified microchannel generated by LIDEP force. The decay time of the diffusion of the concentration distribution agreed well with theoretical calculations, confirming the applicability of MODS as a technique for measuring the diffusion coefficient.