Dielectrophoresis (DEP) Based Microfluidic Particle Separator

This report introduces a microfluidic system for manipulation and separation of micron-sized particles based on the combined use of negative dielectrophoresis (DEP) and hydrodynamic forces. A 2-D micro-electrode structure has been constructed on the bottom surface on glass wafer and driven with high-frequency AC voltage to generate dielectrophoretic gates. Depending on the relative strengths of the two forces, particles such as polystyrene beads carrying by laminar flow can either penetrate the gate or settle down there. This gives rise to certain applications including selectively concentrating particles from the flow, separating particles depending on their sizes or dielectric properties, and automatically positioning particles to selective locations. For this purpose, a microfluidic device consisting of an electrode array sitting on the channel has been fabricated using micro-fabrication techniques. Polystyrene beads were used to study the performance of the device. Experimental results including the concentration and separation of particles are presented.