BEHAVIOR IN ELECTRIC FIELDS OF SIMPLE BIOLOGICAL MEMBRANES

Abstract

The latest studies in biophysics and biochemistry have revealed the major role that liquid crystals (LC) and related phenomena play in biological processes. To account for a number of membrane mechanisms in view of the theoretical model developed by S. J. Singer, studies were carried out on mixtures of fatty acids (arachidic, lauric, butyric) and cholesterol in different weight percentages. Such mixtures may help one understand some mechanisms on which the operation of biological membranes relies. To this end, the way these mixtures behave in an electric field was studied. Electric measurements were conducted from which the average time of electric relaxation (τ) and average electric permittivity (ε r ) were determined. Depending on cholesterol percentage, changes by more than one order of magnitude were found to occur in the electric relaxation time. The ratio between the various fatty acid components did not influence the average time τ in any significant manner. By contrast, the relative electric permittivity ε r was seen to decrease by at least one order of magnitude with raising the cholesterol percentage. The electric properties of such systems essentially depend on changing the amount of cholesterol in the system.