Abstract

The formation of transient aqueous pores is a critical process in biological membranes, governing phenomena from cell signaling to drug delivery. This study investigates the influence of lipid asymmetry—a fundamental characteristic of biological membranes—on the mechanism and kinetics of pore formation. Using model lipid bilayers, we systematically varied the lipid composition between the inner and outer monolayers to mimic the native asymmetry observed in cellular membranes, focusing on differences in headgroup charge and acyl chain saturation. Our primary objective was to determine how this asymmetry affects the membrane's mechanical stability and its propensity to undergo pore creation under external stress, such as an applied electric field. We employed electrophysiological techniques and molecular dynamics simulations to monitor pore nucleation, expansion, and resealing. Key findings reveal that asymmetry significantly lowers the energy barrier for pore formation compared to symmetric membranes, particularly when the outer leaflet contains a higher proportion of negatively charged lipids. This suggests that the differential packing and intrinsic curvature stress induced by asymmetry destabilize the bilayer structure. The results provide crucial insights into the biophysical principles governing membrane integrity and offer a foundation for designing more effective liposomal drug carriers and understanding cell death pathways.