Line tension and structure of through pore edge in lipid bilayer

Abstract

Theoretical model of structure of through pore in lipid bilayer is developed. We assumed that hydrophobic void can appear between monolayers of the membrane. The void is supposed to be filled by organic solvent or low-polarity impurities, which are usually present in artificial and cell membranes. The pore edge was divided to three regions: two monolayer and one bilayer, which surfaces were assumed continuously conjugated. The line tension of the edge was calculated in the framework of theory of elasticity of liquid crystals adapted to lipid membranes. The energy of boundary of hydrocarbon lipid chains with the void was also taken into account. We calculated the pore edge line tension for different volumes of the void. It appeared that at low surface tension at the void’s boundary the line tension decreases for increasing void volume. For zero volume the obtained line tension value is 6.8 pN, which is in accordance with available experimental data.