PROPERTIES OF LIPID BILAYER MEMBRANES - DETERMINATION OF MEMBRANE THICKNESS

A method is proposed to understand the structure of the lipid bilayer in terms of the asymmetric dielectric constant. According to the model concerning the oriented hydrocarbon assembly, the dielectric constant is asymmetric. Here, the oriented hydrocarbon layer is considered as the model of the lipid bilayer. With two independent experimental measurements on the same lipid bilayer and the knowledge of an asymmetric dielectric constant, the thickness, average interchain distance and the dielectric constant of the bilayer, which are consistent with the data from the two experiments, were obtained. Relying upon two independent experimental data (capacitance measurements and optical reflectance measurements) on lecithin bilayers, the correct thickness (54 Å), the interchain distance (4.81 Å) and the dielectric constant (ε{lunate} ∥ ∼- 2.37, ε{lunate}⊥ ∼- 2.65) were deduced. © 1969.