Studies on dielectrophoretic separation using biochips with different electrode shapes

Dielectrophoresis (DEP) is a promising method for the automated separation of biological cells in a miniaturized format. This technology allows cells to be manipulated electronically while suspended in a microfluidic channel embedded in a silicon lab-on-chip. Different dielectrophoretic configurations have been designed and fabricated using micro-electro-mechanical- systems (MEMS) technology, which are investigated comparatively on their function principles and separation efficiencies. DEP responses of colloidal polystyrene particles with the diameters of 10.9µm and 21.3µm suspended in deionized water are measured. It is found that, at the low medium conductivities used, global or local extreme points of electric fields can be configurated dependent on shapes and geometry sizes of electrodes. In addition, all the new phenomena appeared during whole experiment are observed, which may provide novel methods to separate micro particles.