Molecular simulations of mesoscopic bilayer phases

Dissipative particle dynamics simulations are used to study the self-assembly of lipids into bilayers. With a simple mesoscopic lipid-water model, we observe the formation of the liquid crystalline phase L-alpha and gel phases in which the tails are interdigitated L-betaI or noninterdigitated L-beta. For double-tail lipids experiments show all three phases, while for single-tail lipids only L-beta and L-alpha are observed. We show that at sufficiently high head-head repulsion the L-betaI is stable for single-tail lipids. This suggests that it might be possible to induce an L-beta-->L-betaI transition by adding chaotropic salts.