COMPOSITIONAL-MECHANICAL INSTABILITY OF INTERACTING MIXED LIPID-MEMBRANES

We consider lateral phase separations in mixed vesicles that are compr ised of neutral and charged lipids and which interact with each other at close distances. Their demixing transition is driven by the electro static interaction between the bilayers, and is due to enhanced screen ing of the in-plane repulsions by counterions shared between the two s urfaces. Buckling of the membranes further facilitates the phase separ ation and lowers the interbilayer energy. We propose this instability as a precursor for vesicle fusion.