(259c) Characterization of the Phase Behavior of Phospholipid Bilayers

Over the past few years, phospholipid bilayers have attracted large interest as a model for biological membranes. Molecular simulation studies of phospholipid bilayers have been central in the understanding of fundamental properties related to the structure and dynamics of these systems. A number of molecular models have been developed for phospholipids that were optimized to reproduce certain physical properties at specific conditions, more specifically at certain temperature. Simulation studies involving phospholipid bilayers consider their properties at a single temperature assuming that the bilayer is in its fluid state, that is, liquid crystalline phase. The bilayer properties are direct dependent on the fluid state, which is dependent on the temperature of the simulations. We present here our study to determine the phase transition of several commonly used phospholipids bilayers (pure and mixture systems). We perform several molecular dynamics simulation of fully hydrated phospholipids and evaluate a number of properties to assess the temperature range of the phase transition, from a liquid crystalline to a gel state.