Analyzing and Manipulating Solid Supported Membranes with the Atomic Force Microscope

S. Loi, H. Müller, Gexiao Sun1, V. Franz, Ernst Bamberg2, and Hans-Jürgen Butt Laboratory for Physical Chemistry and Theoretical Chemistry, University of Siegen, Adolf-Reichwein-Str., D-57068 Siegen, Germany, 1Max-Planck-Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany, and 2Max-Planck-Institute for Biophysics, Kennedyallee 70, D-60596 Frankfurt/Main, Germany e-mail: butt@chemie.uni-siegen.de URL: http://www.uni-siegen.de/dept/fb08/abteil/pcii

Solid supported lipid bilayers are model systems for biological membranes. Solid supported membranes have been used to study protein-membrane interaction, the structure of membrane associated proteins or the transport of ions through membrane proteins. We analyze membranes and membrane proteins with the atomic force microscope (AFM). Results obtained with the myelin basic protein are presented. During the experiments a method to write protein or polymer regions into solid supported membranes with the tip of the AFM was discovered. Currently, our interest is focused on the tip-lipid interaction. In AFM studies of solid supported membranes often a defined jump of the tip through the membrane is observed once a certain threshold force has been exceeded. We presented two complementary models to describe membrane rupture.