Coarse-grain simulation studies of lipid vesicles

We model the shape evolution of an initially spherical lipid vesicle when the lipid bilayer undergoes a transition from an untilted phase to a tilted phase. Our coarse-grain model is a generalization of an approach due to Lykotrafetis, Zhang, Suresh and Li [preprint], and is efficient enough to allow simulation of an entire vesicle in three dimensions. Topological defects are generated during the phase transformation with a total topological charge of +2 as required by the Gauss-Bonnet theorem. These defects couple to the curvature of the membrane. We explore the resulting complex shape evolution and compare to both theoretical predictions and experimental observations.