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.