Dielectrophoretic trapping of beads in compact capillary-driven systems with multiwall electrodes

We present a concept and fabrication of a compact capillary-driven microfluidic chip with multiwall electrodes for dielectrophoresis-based microbead trapping. The fabrication process comprises two photolithography steps and a lowtemperature (45 °C) cover film lamination. The process enables the realization of hydrophilic channel walls where up to three walls can have metal electrodes with 5 μm minimum feature size inside 20 μm deep channels. Owing to a dielectric recessing step, the patterned electrodes are made level with the surrounding dielectric. Within these microchannels, 10 μm polystyrene beads were efficiently trapped by dielectrophoresis (DEP) while continuous liquid flow was sustained by the capillary pump.