Bilayer lipid membrane permeation and rupture due to hole formation.

A theory is developed for the permeation and rupture of bilayer lipid membranes due to fluctuation formation of holes (or pores) in them. The two monolayers of the bilayer lipid membrane are considered as mutually adsorbed on each other and the bilayer lipid membrane equilibrium is described by an adsorption isotherm in mean field approximation. The theory of nucleation is used for determination of the work for hole formation and the hole equilibrium size distribution as functions of the concentration C of monomer lipid in the solution. The bilayer lipid membrane permeation and rupture are analyzed from a unified point of view and expressions are derived for the dependence of the bilayer lipid membrane diffusion permeability coefficient and lifetime on C. The effect of foreign bodies (e.g., proteins) on the bilayer lipid membrane permeation and rupture is considered and a possible experimental application of the theory is discussed. The results obtained are directly applicable to dense monolayer films on liquid surfaces.