Design and simulation of electrodes for 3D dielectrophoretic trapping

Micro- and nano-particles can be trapped in locally strong or weak regions of a non-uniform electric field through the effect of dielectrophoretic principle. Recently, a novel optoelectronic tweezers (OET) based on optically induced dielectrophoresis (DEP) was demonstrated by Chiou et al. [1] for effectively trapping and manipulation of cells and latex particles. The OET allows an optical beam to create a virtual electrode on a photoconductive surface, which produces a highly non-uniform electric field. Here we simulated the electric field distribution produced by a light-induced ring-shaped electrode for particles trapping. Then, we simulated the DEP trapping effects from a real microelectrode that could be fabricated on a glass substrate to replace the virtual light-induced electrode. This is to compare the efficiencies of OET and microelectrode induced DEP effects. We also derived the smallest radiuses of the polystyrene bead which could be potentially trapped in the OET device and the real electrode structure. Finally, we designed and analyzed a 3x3 electrode array to explore the possibility of arbitrarily trapping and manipulating single particles using the real microelectrodes.