Electrostatic Edge Instability of Lipid Membranes

cell ghosts (Steck et. al., Science 168:255(1970)). Lipid membranes, the sheets which form the boundaries of cells, must maintain their integrity for cells to live [1]. Since a tear in a membrane exposes the hydrophobic interior of the sheet to water, tradition maintains that membranes have a high line tension (energy per unit length of exposed edge) and never spontaneously form holes. We show that membranes can form holes in a simple model of a charged membrane. By examining the competition between electrostatic repulsion and line tension, we find a parameter range where electrostatics dominates and membranes are unstable to hole formation. Although much previous work examines electrostatic effects on lipid assemblies [2] and the bending moduli of membranes [3–5], we are only aware of one study addressing electrostatics and line tension [6].