Biophysical aspects of dielectrophoresis

Dielectrophoresis, the translational motion produced by the action of a nonuniform electric field upon neutral polarizable bodies, is proving useful in handling biological systems. It is especially useful in studies of suspensions of cells. Normal and abnormal cells respond differently, and may be separated on the basis of their differing polarizational response. Because the phenomenon depends upon the polarization and not upon the charge of the particles, subtle new differences are available for exploitation by dielectrophoresis. Operation can be carried out in a high frequency electric field. The frequency “spectrum” of cellular response to dielectrophoresis varies with the species, and with the physiological state of the individual cell. Cells may be studied individually or in large numbers at a time. Cells may be gathered and formed into “fleshlike” aggregates using dielectrophoresis.Extension of the techniques to the study of the fundamental nature of the polarizabilities of cells and subcellular particles should provide useful insight into the roles of electronic, atomic dipole orientational, and nomadic polarization, as well as that due to interfacial (Maxwell-Wagner) polarization in biological systems.