Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 14: Membranes and Vesicles

BP 14.5: Vortrag

Mittwoch, 28. März 2012, 10:45–11:00, H 1028

Rotational diffusion of micrometer-sized solid domains in lipid membranes — •Eugene P. Petrov, Rafayel Petrosyan, and Petra Schwille — Biophysics, BIOTEC, Technische Universität Dresden, Dresden, Germany

The Saffman–Delbrück approximation for translational and rotational diffusion of membrane inclusions [1] is widely used in biophysical studies to relate the inclusion size to the membrane viscosity, but is limited to small inclusion sizes, typically not exceeding 100 nanometers. Although an exact solution of the problem has been derived [2], its computational complexity precludes its practical applications. To overcome this difficulty, we recently developed a simple high-accuracy analytical approximation for the translational diffusion coefficient of a membrane inclusion [3]. Using a similar approach, here we develop a simple and accurate approximation for the rotational diffusion coefficient of a membrane inclusion valid for all combinations of the inclusion size and viscosities of the membrane and surrounding media. We demonstrate the utility of our approximation by using it to analyze our experimental data on rotational diffusion of gel-phase domains on giant unilamellar vesicles showing fluid–gel coexistence.
P. G. Saffman and M. Delbrück, Proc. Natl. Acad. Sci. USA 72 (1975) 3111; P. G. Saffman, J. Fluid Mech. 73 (1976) 593
B. D. Hughes, B. A. Pailthorpe, and L. R. White, J. Fluid Mech. 110 (1981) 349
E. P. Petrov and P. Schwille, Biophys. J. 94 (2008) L41