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BP: Fachverband Biologische Physik

BP 13: Posters: Biological Membranes

BP 13.7: Poster

Monday, March 14, 2011, 17:15–20:00, P3

Characterization of polymer-supported lipid membranes by X-ray and neutron reflectivity — •Fernanda F. Rossetti¹, Emanuel Schneck¹, Giovanna Fragneto², Oleg Konovalov³, and Motomu Tanaka¹ — ¹Physical Chemistry of Biological Systems, University of Heidelberg, 69120 Heidelberg, Germany — ²Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble, France — ³European Synchrotron Radiation Facility, Beamline ID 10B, 38043 Grenoble, France

Polymer-supported lipid membranes recently attracted increasing interest as planar models of cell membranes. Their major advantage over solid-supported membranes is a reduced frictional coupling between transmembrane proteins and the solid support, which reduces the risk of protein denaturation. However, the structures of such two-dimensional model membranes on the molecular level are still unknown. Here, we present a quantitative study–performed by X-ray and neutron reflectivity at the solid-liquid interface–of artificial and native lipid membranes prepared on polymer cushions made of ultrathin films of regenerated cellulose. The reflectivity results were consistent with the formation of homogeneous membranes over a macroscopically large area and allowed us to extract the properties of both the membrane and the cellulose layer. The interfacial forces acting between the membranes and the substrates were calculated by including contributions from Van der Waals, Helfrich and hydration forces. The resulting membrane-substrate equilibrium distance was found to coincide with the measured thickness of the hydrated cellulose films.