Novel design of multiphase optoelectronic microfluidic device for dielectric characterization of single biological or colloidal particles

A novel multiphase optoelectronic microfluidic device (MOMD) based on optoelectronic effect and multiphase dielectrophoresis (DEP) is designed by our group for accurate dielectric characterization and flexible manipulation of individual microscopic particles, which overcomes the drawback that the conventional microfluidic devices cannot accurately characterize single bio-particles. The microelectrode layer of MOMD integrating quadrupole electrodes and spiral electrodes is designed for the dielectric measurements of micro particles, while the photoconductor of MOMD is designed for the dynamic manipulation of the particles. The numerical simulation is implemented for the distribution of time-averaged dielectrophoretic force, torque and particle velocities. The results agree well with the experiments in the literature. The numerical results show that both real and imaginary parts of particle effective polarizability α̃ determining the particle characteristics can be calculated simultaneously through measuring the traveling velocity V
r
of the particles, which is simpler than previous methods. Moreover, the results also show that the particle travelling velocity, suspension height and electrorotation velocity can all be measured accurately for dielectric characterization with the help of light-induced DEP mechanism integrated on the MOMD. The MOMD needs not the expensive optical tweezer system for single particle manipulation, and therefore has a greatly low cost.