Electrohydrodynamic-mediated dielectrophoretic separation and transport based on asymmetric electrode pairs

This paper presents a system for continuous separation and transport of micron and submicron particles in fluidic environment based on dielectrophoretic fractionation in concert with AC electrothermal (AC ET)-induced fluidic pumping action. In this system, high frequency AC signals are used to energize asymmetric electrode pairs. AC ET-driven fluidic pumping is utilized as an alternative to the commonly used external pressure-driven fluid flow. Distinct collection sites for negative-dielectrophoretic and positive-dielectrophoretic particle populations are identified. The coupling effects of dielectrophoretic force and viscous drag from AC ET fluid flow on particle motions are investigated theoretically and numerically. We demonstrate that these two forces can be efficiently coupled to achieve continuous separation and transport of particle mixture in a fluidic medium when the dielectric properties of the particles and the fluidic environment are different. The combination of dielectrophoretic separation and AC ET pumping function provides a promising approach to further miniaturize and integrate these mechanisms into lab-on-chip devices.