Fluid elasticity enhanced insulator-based dielectrophoresis in a very dilute polymer solution

Insulator-based dielectrophoresis (iDEP) is an emerging technique that has been increasingly used for particle and cell manipulation in microfluidic devices. However, the majority of the previous studies on iDEP is based upon Newtonian fluids. We demonstrate in this work that the addition of a very small amount of polyethylene oxide (PEO) polymer (~50 ppm) into a buffer solution can significantly enhance the iDEP focusing of particles in a constriction microchannel. We also perform a parametric study of the effects of polymer concentration, polymer molecular weight, and particle size on such fluid elasticity enhanced iDEP (E-iDEP).