DEP based cell separation utilizing planar microelectrode array

We describe the utility of the dielectrophoresis (DEP) effect, employing planar microelectrode arrays fabricated on a glass substrate to synthesize a specially shaped nonuniform field, to fractionate cells into purer subpopulations. The arrangement of planar microelectrodes is similar to those employed by others, however, in our case the a.c. voltage applied to each electrode is individually tailored so as to improve both the efficiency of cell sorting and sample throughput. Furthermore, since DEP may impel particles into region of field intensity maximum (i.e. positive DEP) or minimum (i.e. negative DEP) over different regions of the applied field frequency spectrum this biasing planar electrode biasing scheme allows us to exploit both positive and negative DEP effects to affect cell separation. Results obtained on plant protoplast cells, using this new DEP cell fractioning scheme, confirm our theoretical predictions and furthermore demonstrates the improvements in separation efficiency and throughput over a wide range of applied field frequencies.