Dynamics of Membranes and their constituents

Anomalous and anisotropic diffusion of hydration water in fluid lipid membranes

Not scheduled

15m

Auditorium (Palaestra and Kulturen)

Speaker

Felix Roosen-Runge (Division for Physical Chemistry, Lund University)

Description

We report on diffusion of hydration between phospholipid membranes using incoherent quasi-elastic neutron scattering (QENS) and computer simulations [1]. The combination of a well-aligned stack of DMPC membranes with the large, 2-dimensional detectors available at the neutron spectrometer Let (ISIS, UK) allows for simultaneous access to water motions lateral and perpendicular to the membranes. The resulting 2-dimensional maps of relaxation time and stretching exponent evidence anomalous (sub-diffusive) and anisotropic diffusion of membrane hydration water varying on nanometer distances. By combining molecular dynamics and coarse-grained Brownian dynamics simulations, the overall behavior is reproduced, and the apparent features can be linked back to an intrinsic sub-diffusivity of water at picosecond time scales, and the anisotropy of confinement and local dynamical environments.
[1] Toppozini et al. Soft Matter 11 (2015) 8354