Continuous Label-Free Particle Separation Via Wall-Induced Lift in Electrophoresis

The efficient separation of discrete particle (both synthetic and biological) species is a topic of interest in numerous research fields for its practical application to problems encountered in both academia and industry. We demonstrate in this work a novel continuous-flow label-free method for electrokinetic separation of particles based on size and/or surface charge. This method utilizes the wall-induced non-inertial lift force to deflect a sheath flow-focused particle mixture to property-dependent positions in a straight microchannel. A numerical model is also developed to understand this separation and to study the parametric effects on it. The numerical predictions are found to agree reasonably with the experimental observations.