Three-Phase Coexistence in Binary Charged Lipid Membranes in a Hypotonic Solution

We investigated the phase separation of dioleoylphosphatidylserine (DOPS) and dipalmitoylphosphatidylcholine (DPPC) in giant unilamellar vesicles a hypotonic solution using fluorescence confocal laser scanning microscopy. Although charged lipid membranes is generally suppressed by electrostatic repulsion between headgroups, osmotic stress can promote formation domains. Interestingly, we observed three-phase coexistence even DOPS/DPPC binary mixtures. The three phases were DPPC-rich, dissociated DOPS-rich, nondissociated DOPS-rich phases. two forms DOPS found to coexist owing ionization headgroup, such that system could be regarded as quasi-ternary. formed with differently ionized domains successfully identified experimentally monitoring adsorption positively particles. In addition, coarse-grained molecular dynamics simulations confirmed stability coexistence. Attraction mediated hydrogen bonding protonated molecules reduction interactions at domain boundaries stabilized