Optimal design of 3-D carbon microelectrode array for dielectrophoretic manipulation of nanoparticles in fluids

Manipulation of nanoparticles using nonuniform electric fields is an area of growing interest for nanotechnology applications. This article presents a design methodology and numerical analysis of electric fields and dielectrophoretic forces for 3-dimensional (3-D) carbon microelectrode array, overcoming the limitations of previous approaches. A description of the boundary element method is developed to compute electric field distribution much precisely. The effects of electrode shape, spacing, width and height on field distribution are considered. The results show that the gradient magnitude produced by square column electrodes is most effective to realize manipulation of nanoparticles in fluids. As both the electrode spacing and width are reduced the field gradient magnitude increases exponentially. By increasing the height of electrodes, the electric field extends largely in the electrode locality, which is advantageous to improve the manipulation efficiency with high degree of precision, flexibility and throughput. The theoretical predictions will provide design guides for 3-D carbon microelectrode array towards manipulation of nanoparticles in fluids, which have been shown in reasonable agreement with literature experimental reports.