Study of water diffusion on single-supported bilayer lipid membranes by quasielastic neutron scattering

¹ Department of Physics and Astronomy and University of Missouri Research Reactor, University of Missouri Columbia, MO 65211, USA
² Center for Neutron Research, National Institute of Standards and Technology - Gaithersburg, MD 20899-6102, USA
³ Department of Materials Science and Engineering, University of Maryland - College Park, MD 20742, USA
⁴ Spallation Neutron Source, Oak Ridge National Laboratory - Oak Ridge, TN 37831, USA

^a taubh@missouri.edu

Received: 27 March 2012
Accepted: 23 April 2012

Abstract

High-energy-resolution quasielastic neutron scattering has been used to elucidate the diffusion of water molecules in proximity to single bilayer lipid membranes supported on a silicon substrate. By varying sample temperature, level of hydration, and deuteration, we identify three different types of diffusive water motion: bulk-like, confined, and bound. The motion of bulk-like and confined water molecules is fast compared to those bound to the lipid head groups (7–10 H₂O molecules per lipid), which move on the same nanosecond time scale as H atoms within the lipid molecules.