Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 7: Posters I
BP 7.44: Poster
Montag, 25. Februar 2008, 17:00–19:30, Poster A
Characterization of polymer-supported native membranes by X-ray and neutron reflectivity — •Fernanda Rossetti1, Emanuel Schneck1, Stefan Kaufmann1, Murat Tutus1, Oleg Konovalev2, Giovanna Fragneto3, and Motomu Tanaka1 — 1Biophysical Chemistry Laboratory II, University of Heidelberg, Germany — 2European Synchrotron Radiation Facility, Grenoble, France — 3Institut Laue Langevin, Grenoble, France
Polymer-supported artificial and/or native membranes attract increasing interest as planar models of cell membranes. Immuno-fluorescence labeling experiments have demonstrated that native cells and microsomes can be spread on polymer "cushions" based on ultrathin films of regenerated cellulose. However, structures of such "two-dimensional biological membranes" on the molecular level are still unknown. This poster will present a quantitative study--performed by X-ray and neutron reflectivity measurements at the solid-liquid interface--of structures of bio-membranes on cellulose cushions that mimic the extracellular matrix (ECM). The films are prepared by Langmuir-Blodgett transfer, so that the thickness can be controlled within nm accuracy in the range of ~ 5-50 nm. It will be shown that the deposition of several types of natural bio-membrane extracts (sarcoplasmic reticulum membranes, human erythrocyte ghosts, HeLa cell membrane extracts) results in a clear change in the global shape of the reflectivity curves for cellulose supports of different thickness. The observed changes coincide with the formation of homogeneous polymer-supported lipid membranes over a macroscopically large area.