Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 56: The Physics of Water Interactions with Biological Matter (Joint Focus Session with CPP)
BP 56.8: Vortrag
Donnerstag, 10. März 2016, 12:30–12:45, H37
Anomalous and anisotropic diffusion of hydration water in fluid lipid membranes — •Felix Roosen-Runge1, Laura Toppozini2, and Maikel Rheinstädter2 — 1Institut Laue-Langevin, Grenoble, France — 2McMaster University, Hamilton, Ontario, Canada
Water diffusion in heterogeneous environments is a relevant and frequently studied phenomenon in experiment, simulation and theory. We report on water diffusion 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, τ, and stretching exponent, β, 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