Dielectric Spectroscopy and Membrane Organisation

Abstract

The possible bases for field-mediated effects on cellular processes are reflected in the passive electrical properties of biological systems. The historical, present and prospective utility of dielectric spectroscopy in assessing the static and dynamic organisation of biological membranes is reviewed within this context. The basis for the view that the static capacitance of bioraembranes is as great as 1 fiF/cm² is doubted; contributions from the (partially restricted) motions of membrane components, and of double-layer ions, probably contribute to this apparent value in bioraembrane vesicle suspensions. The importance of improving our knowledge of the static electrical capacitance of energy coupling membranes is stressed. Theoretical and experimental procedures for assessing the contribution of rotational and translational motions of membrane components, and of double-layer/membrane interactions, to dielectric spectra in the approximate frequency range 10 to 10⁷ Hz are described. Finally, three outstanding and generally unsolved problems requiring further work are detailed.