On the freezing behavior and diffusion of water in proximity to single-supported zwitterionic and anionic bilayer lipid membranes

We compare the freezing/melting behavior of water hydrating single-supported bilayers of a zwitterionic lipid DMPC with that of an anionic lipid DMPG. For both membranes, the temperature dependence of the elastically scattered neutron intensity indicates distinct water types undergoing translational diffusion: bulk-like water probably located above the membrane and two types of confined water closer to the lipid head groups.

The membranes differ in the greater width of the water freezing transition near the anionic DMPG bilayer compared to zwitterionic DMPC as well as in the abruptness of the freezing/melting transitions of the bulk-like water. © CopyrightEPLA, 2014.