330 - Determination of surface charge of bilayer lipid membranes

Abstract

The determination of the membrane surface charge is based on the measurement of the surface potential difference at both sides of the bilayer lipid membrane (BLM) connected with the asymmetrical concentration of the electrolyte in both solutions. In the short-circuit regime the intramembrane potential jump is caused by the difference in the two surface potentials. In order to find the intramembrane potential jump the BLM capacitance dependence on voltage was used. In some range of electrolyte concentrations a dependence of the potential jump on the surface charge was found. The charge density was calculated by applying the Gouy-Chapman theory of the diffuse double layer. Surface charges were determined for BLM of common bovine brain lipids, phosphatidylethanolamine, dioleyllecithin and azolectine.