Composition dynamics in lipid bilayer membranes over long length and time scales

We present a stochastic phase-field model for multicomponent lipid bilayers, which explicitly accounts for the quasi-two-dimensional hydrodynamic environment unique to a thin fluid membrane immersed in aqueous solution. Dynamics over a wide range of length scales (from nanometers to microns) for durations up to seconds and longer are readily accessed and provide a direct comparison to fluorescence microscopy measurements in ternary lipid/cholesterol mixtures. Simulations of phase separation kinetics agree with experiment and elucidate the role of hydrodynamics in the coarsening process.