SELECTIVE DIELECTROPHORETIC CONFINEMENT OF BIOPARTICLES IN POTENTIAL-ENERGY WELLS

The potential energy surfaces generated by microelectrodes of polynomi al and interdigitated castellated geometry have been calculated for pa rticles experiencing both positive and negative dielectrophoretic forc es. The resulting forms of particle collection at these electrodes are governed by the locations of the potential energy wells, and the theo retical predictions of the modes of collection for particles experienc ing positive and negative dielectrophoretic forces are verified using mixtures of viable and non-viable yeast cells, as well as of bacteria and blood cells. An important result for the interdigitated electrodes is the finding that particles trapped in potential energy wells under the action of negative dielectrophoresis can be more easily removed f rom the electrode structure (e.g. by fluid flow or gravitational force s) than those trapped under positive dielectrophoresis. This was verif ied for mixtures of bacteria and blood cells, viable and non-viable ye ast cells.