Structure and Interactions of Weakly Ordered Lipid Model Membranes

Georg Pabst, Michael Rappolt, Heinz Amenitsch, and Peter Laggner

Institute of Biophysics and X-ray Structure Research, Austrian Academy of Sciences, Schmiedlstraße 6, A-8042 Graz, Austria

We have developed a global x-ray data analysis technique, which accounts for the quasi-long range order and diffuse scattering displayed by phospholipid membranes [1, 2]. Such systems are frequently taken as mimics for biological cell membranes. With our method we are able to determine structural parameters, such as the membrane thickness, and fluctuations that depend on the bilayer bending rigidity. We demonstrate the applicability of the method on various lipid/water systems including phase transition phenomena and give a comparison and outlook to surface diffraction on solid supported lipid films.

[1] G. Pabst, M. Rappolt, H. Amenitsch, and P. Laggner, Phys. Rev. E 62, 4000 (2000)

[2] G. Pabst, R. Koschuch, B. Pozo-Navas, M. Rappolt, K. Lohner, and P. Laggner, J. Appl. Cryst. 36, 1378 (2003).