Research of Three-dimensional Grid Biosensor Based on Integration of Dielectrophoretic Trap and Impedance Testing

The integration of separation and testing was the bottleneck of the micro total analysis system. Based on the combination of dielectrophoresis and impedance measurement, the three-dimensional (3D) dieletrophoretic chip was designed. The key structure of the chip comprised three layers: lower electrodes, upper electrodes, and the sandwiched SU8 photoresist layer. The SU8 photoresist interlayer had the columned trap array. It formed the special distribution of electric field on the ground of 3D array and the SU8 dielectric layer. The distribution can decrease the voltage and entrap the particulate to the wells which is convenient for impedance measurement. The 3D chip has higher sensitivity than the plane electrode chip because it has the non-dispersive electric field. The switch of the dielectrophoresis and impedance measurement for same electrode has the advantage of easy facture and rapid testing.