Regensburg 2010 – scientific programme

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BP: Fachverband Biologische Physik

BP 31: Posters: Membranes and Vesicles

BP 31.18: Poster

Thursday, March 25, 2010, 17:15–20:00, Poster B1

Mechanics of Small Unilamellar Vesicles — •Sai Li, Frederic Eghiaian, and Iwan Schaap — III. Physkalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany

Lysosomes, enveloped viruses, synaptic and secretory vesicles are all examples of natural nano-containers (diameter ~100 nm) which specifically rely on their lipid bi-layer to protect and exchange their contents with the cell. We have developed methods primarily based on atomic force microscopy that allow precise investigation of the mechanical properties of these vesicles. The mechanical properties of small, spherical vesicles were probed by applying very low forces (0.1-0.3 nN), which led to a maximum 30 % deformation. The effects of lipid composition, temperature, osmotic pressure and the radius of curvature were studied for liposomes with diameters between 30 and 150 nm. In order to extract the lipid bi-layer elastic constants we used finite element methods to model the measured deformations. The elastic constants we found for the lipid bi-layer were in very good agreement with previously reported experiments on micrometer-sized giant vesicles. We will discuss the effects of parameters that increase the stiffness in relation to the high curvature of the vesicles.