ABSTRACT
Interactions between lipid membranes play important roles in numerous biological processes. Their characteristics reflect an interplay of various interfacial forces. While continuum theories successfully describe long-range mechanisms like electrostatic, dispersion, and undulation interactions, solvent-explicit simulations are required to elucidate the strong repulsion between membranes at nanometer separations known as hydration repulsion. In this chapter, we review simulation techniques that enable the study of short-range interactions between lipid membranes. One of the main challenges is to precisely account for the chemical potential of water between the membrane surfaces. We present conclusions from several simulation studies performed over the recent years that yielded important insights into the mechanisms underlying the hydration repulsion between biological membranes. As it turns out, there is not a single universal mechanism, but rather several competing contributions whose relative magnitudes depend on the membrane phase and the lipid chemistry.
