Multiple electrodes arrayed dielectrophoretic chip with application on micro-bead manipulation

This paper investigates new types of dielectrophoretic (DEP) chips which consist of arrayed electrodes and 3D microstructures. The goal is to optimize the sorting, trapping, and manipulating ability of the DEP chip, which is operated with negative-dielectrophoretic forces. As different from conventional DEP chips using only planar electrodes, these new DEP chips consist of ITO top and bottom electrodes, an arrayed gold middle electrode, and an arrayed SU-8 3D micro structure. In order to achieve single-bead manipulation, the size of the SU-8 3D micro structure array matches the size of the beads. It is shown that such a 3D structure not only yields a non-uniform electric field for DEP trapping but also enhances the capability of positioning and immobilization of the trapped beads. In theoretical analysis and simulation, Comsol Multiphysics is applied to simulate the DEP forces in these chips. Experimental results show that the chips can successfully trap and manipulate beads by applying different electrical voltage signals with phase angles on the triple layer electrodes. In order to realize the optimum frequency to operate DEP force, we also investigate the electrical conductivity at different particle sizes. In summary, we fabricate new DEP chips with improving capability of particle sorting, trapping, and manipulating. The design, analysis, and fabrication processes are discussed in details.