Dynamics of dielectrophoretic field-flow fractionation (dep-fff) based micro sorter for cell separation

Dielectrophoretic Field-Flow Fractionation (DEP-FFF) is a technique that selects particles of interest from a mixture of many samples. Conventional DEP-FFF technique used DEP force to levitate particles to different heights according to their dielectric properties. Levitated particles are then separated by their velocity difference in a microchannel. Numerical simulation and experimental results found that particles become wavy trajectory when the ratio of levitation height (h_p) and average of electrode width and spacing (d) is below 0.6 (h_p/d<0.6). In the mean time, sorted particles disperse randomly in Y-direction, too. The wavy trajectory and random distribution cause cell separation imprecisely. A novel MEMS-fabricated DEP-FFF based micro sorters is designed to improve these problems. The experimental results show that the particles can be levitated to a constant height and focus into a single particle stream along the centerline in the new micro sorter design. One can conclude that the new design leads to better cell separation in a DEP-FFF based micro sorter.