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BP: Fachverband Biologische Physik

BP 38: Membranes and Vesicles I

BP 38.9: Vortrag

Mittwoch, 22. März 2017, 12:15–12:30, HÜL 386

Solid-supported DMPC multilayers containing cholesterol at high hydrostatic pressure — •Göran Surmeier, Michael Paulus, Paul Salmen, Yury Forov, Susanne Dogan, Lukas Tepper, Benedikt Nowak, Metin Tolan, and Julia Nase — Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany

A phospholipid bilayer is the basic component of cell membranes, which separates the intracellular and extracellular region. Bilayers undergo pressure- and temperature-induced phase transitions. However, they need their high flexibility, which is given in the liquid phase, to fulfill their biological functionalities. Real membranes are highly complex systems that are interstratified by cholesterol and proteins. Adding cholesterol shifts the phase boundaries of phospholipid bilayers. While these phase transitions were already studied in bulk solutions in detail, the behavior of solid-supported membranes at high hydrostatic pressure is widely unknown.

We present an in-situ high pressure X-ray reflectometry study on the structure of solid supported DMPC bi- and multilayers containing cholesterol in different concentrations. The reflectivities were measured at the solid-liquid interface between silicon and an aqueous buffer solution in a high pressure cell employing pressures up to a maximum of 5000 bar. We observed a decrease of the critical pressure and an expansion of the transition area of the liquid-gel phase transition with increasing cholesterol concentrations at 37°C and were able to determine the cholesterol concentration-dependent behavior of the compressibility of gel phase membranes at 20°C.