Protein dielectrophoresis in an exact nanotrap

Dielectrophoresis is the process by which a gradient of the squared electric field imparts motion to a particle. Interest in the phenomenon of dielectrophoresis has gained significant attention in recent years due to its potential in the sorting, manipulation, and trapping of solutes such as proteins in aqueous solutions. For many decades protein dielectropheresis was considered impossible, as the predicted magnitude of the force arising from experimentally accessible field strengths could not out-compete thermal kicks. This conclusion was drawn from the mainstay Clausius-Mossotti result for the susceptibility of the dielectrophoretic force. However, the CM result is inappropriate for proteins. By accounting for the repulsive core of the protein and the polarization of the solvent by its permanent dipole, a corrected susceptibility may be obtained. Here we propose an explicit geometry within which the correction may be put to the test. Trapping distances are explored as a function of the applied field strength and pore size.