Berlin 2005 – scientific programme

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AKB: Biologische Physik

AKB 60: Membranes and Vesicles

AKB 60.2: Talk

Tuesday, March 8, 2005, 16:15–16:30, TU H2013

Shapes of crystalline domains on spherical vesicles — •Stefanie Schneider and Gerhard Gompper — Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany, Email: st.schneider@fz-juelich.de

The background to this work is the experimental observation of a variety of shapes of the crystalline domains on giant unilamellar vesicles, consisting of two different lipids as well as cholesterol [1]. Understanding these systems is important, because they serve as model systems for the far more complex biological lipid bilayers. Important biological functions, such as endocytosis, cell adhesion, signaling and protein organisation, are attributed to the formation of domains in lipid bilayers.

To further understand the domain formation in these systems, we have investigated crystalline domains of different shapes embedded in spherical fluid vesicles using the elasticity theory and Monte Carlo simulations. The stretching energy, which is necessary to deform an ideal crystalline patch onto the surface of a sphere has been calculated for different shapes of the patch (disc, stripe, and a disc including one disclination). A phase diagram has been constructed in which the equilibrium shapes and number of the patches are related to the Young modulus, the line tension between the fluid and the crystalline phase, and the relative area of the vesicle covered by the crystalline phase.

[1] J.Korlach, P. Schwille, W. Webb, G. Feigenson, Proc. Natl. Acad. Sci. USA, 96, 8461(1999)