Electrorotation and levitation of cells and colloidal particles |
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| Authors: | Kenneth R. Foster Friedrich A. Sauer Herman P. Schwan |
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| Affiliation: | Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6392 USA;Max Planck Institut fur Biophysik, D-6000 Frankfurt a.M., Germany |
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| Abstract: | We review dielectrophoretic forces on cells and colloidal particles, emphasizing their use for manipulating and characterizing the electrical properties of suspended particles. Compared with dielectric spectroscopy, these methods offer a measure of independence from electrode artifacts and mixture theory. On the assumption that the particles can be modeled as uniform dielectric objects with effective dielectric properties, a simple theory can be developed for the frequency variation in the field-induced forces. For particles exhibiting counterion polarization, dielectrophoretic forces differ considerably from predictions of this theory at low frequencies, apparently because of double layer phenomena. |
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