Dielectrophoretic Traps and micro-motor for Driving and Sorting Latex Spheres: From Discrete Devices to a lab-on-a-chip

This paper reports dielectrophoretic traps and a micro-motor for driving and sorting latex spheres on a chip with complex structures. A scheme containing function modules for pre-separating, sorting and driving micro-particles in a single chip is proposed. In order to optimize the system design, comparative researches on various electrode geometries of discrete devices from different separation principles are undertaken. Different from the obtained results before, the electrode shapes of all parts have been modified, which makes the dielectrophoresis effects better than those of traditional approaches. Moreover, a novel spiral interdigital or a spiral-castle electrode is used to replace the old spiral electrodes, and more than 90% target particles can be obtained. The separation voltage signal also can be decreased by 50% while using a standing wave instead of a conventional traveling wave. Otherwise, the lateral or axial inhomogeneously castellated electrode is constructed, by which 70% target particles can be sorted. Moreover, for the dielectrophoretic micro-motor composed of a coplanar and quadrupolar electrode structure, it is observed that annular array shaped electrodes in the center can make the device obtain high rotation speed under a low voltage condition.