An efficient cell separation system using 3D-asymmetric microelectrodes

An efficient 3D-asymmetric microelectrode system for high-throughput was designed and fabricated to enhance sorting sensitivities to the dielectric properties - size, morphology, conductivity, and permittivity - of living cells. The principle of the present system is based on the use of the relative strengths of negative dielectrophoretic and drag forces, as in a conventional 3D-microelectrode system. Whereas the typical 3D-microelectrode system has a constant electric field magnitude due to the constant width of the microelectrodes and a fixed gap between face-to-face microelectrodes, the present 3D-asymmetric microelectrode system has electric fields of continuously varying magnitudes along the transverse direction of a channel owing to the changing widths of the electrodes in the half-circular shaped cross section of the microchannel. Thus, varying dielectric forces are generated, leading to increased sorting sensitivity through differentially induced forces to definitely distinct cell types. Numerical analysis verified the improved sensitivity of the present system for sorting living cells. The feasibility of using the newly fabricated system under experimental conditions was tested by demonstrating that a mixed population of mouse P19 embryonic carcinoma (EC) and red blood cells (RBCs) was effectively sorted to different wells depending on their respective relative physical properties.