Simulations of the Rupture of Liposomes Near Solid Surfaces in the Presence of Membrane-Membrane Adhesion

Abstract

The behavior of lipid membranes near solid surfaces has a great significance both in medicine and in technology. In spite of the widespread use and study of such membrane phenomena, their theoretical analysis is rather scarce. Our main goal here is to understand the process during which membrane vesicles first adhere to solid surfaces, then rupture (or go through a series of transient ruptures) due to the mechanical tension induced by the adhesion (not only between the membrane and the surface, but also between two adjacent membrane areas), and finally spread along the surface forming a supported lipid bilayer. In our theoretical description we simultaneously consider the dynamics of spontaneous pore opening and closing; volume loss via leakage through the pores; and the advancement of the adhesion fronts. All these processes are supposed to follow an overdamped dynamics and are coupled to each other through membrane tension.Here we identify under which conditions the dynamics leads to the formation of hat shaped geometries with a projecting brim. We found that the most determining parameters with respect to the shape and dynamics of a vesicle are the drag coefficient along the adhesion front and the line tension along the pore. Using numerical simulations we could reproduce a variety of experimental observations and conclude that a long lasting hat shaped geometry occurs in a limited range of parameters.