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BP: Fachverband Biologische Physik

BP 7: Posters I

BP 7.43: Poster

Montag, 25. Februar 2008, 17:00–19:30, Poster A

Interactions of nanoparticles and semiflexible polymers with inhomogeneous membranes — Florian Rückerl, Lydia Woiterski, Josef A. Käs, and •Carsten Selle — University of Leipzig, Institute for Experimental Physics I, Linnestraße 5, 04103 Leipzig, Germany

Lateral diffusion within membranes plays a major role in biologically important processes as signal transduction. We present experimental studies on diffusion of proteins within or at a variety of inhomogeneous model membranes where two differently ordered phases coexist. We use Langmuir monolayers, planar supported bilayers and giant unilamellar vesicles as membranes in order to rule out effects of surrounding medium and geometry. The diffusants range from fluorescent spheric nanoparticles to linear semiflexible polymers (f-actin) whose motion is monitored by single-particle or single-polymer tracking. Associated to ordered domains, dimensionally reduced motion was observed for nanoparticle diffusion in monolayers and bilayers. Monte-Carlo simulations demonstrate that model protein diffusion can be strongly affected by both the strength of these interactions and the domain size. We conclude that cellular membranes might use similar mechanisms to adjust two-dimensional diffusion for the control of biochemical reactions within the membrane. Furthermore, we expect that our experiments might contribute to a better understanding of actin-membrane interactions.