Lateral Interactions Influence the Kinetics of Metastable Pores in Lipid Membranes

Abstract

The formation of through pores in lipid bilayer membranes occurs in a number of cellular processes and is also applied for biotechnological and biomedical purposes. In the classical theory of pore formation, diffusion of membrane defects in space of radii is considered. When the first pore reaches a critical radius, the membrane irreversibly ruptures. It is usually presumed that the diffusion of defects occurs independently; their possible lateral interactions are not taken into account. In this paper, we consider a possible influence of lateral interactions of metastable through pores on their kinetics. It is assumed that the interaction occurs due to the overlap of elastic deformation fields arising at the edges of two pores. The interaction energy of two circular pores was calculated in the Derjaguin approximation for rapidly decaying potentials. The unidimensional potential of interaction of two linear parallel edges of pores formed in membranes of different lipid composition was calculated in the framework of the theory of elasticity of liquid crystals adapted to lipid membranes. It is shown that this interaction should lead to a considerable reduction of the measured line tension of the pore edge. In addition, the lifetime of two optimally situated metastable pores can increase approximately 10 times due to the interaction. Extrapolation of the obtained results to the case of a larger number of interacting pores makes it possible to predict an additional increase in the lifetime by one or two orders of magnitude.