Paper BI+NC-WeM5
Elasticity Mapping of Pore Suspending Native Cell Membranes

Wednesday, October 22, 2008, 9:20 am, Room 202

The mechanics of cellular membranes is governed by a non-equilibrium composite framework composed of semiflexible filamentous cytoskeleton and extracellular matrix proteins linked to a lipid bilayer. Non-local elasticity information of native cell membranes has so far been gathered by micropipette suction and rheological whole cell experiments. Locally confined measurements were conducted by using membrane-attached beads pulled by laser tweezers and by atomic force microscopy of entire cells. As yet, local mechanical information (elasticity maps) of isolated cellular membranes, such as basolateral membranes of endo- and epithelial cells, are however, not available. Here, we introduce a novel approach that allows the mapping of mechanical properties of native freestanding cellular membranes on a nanometer length scale. Basolateral membranes of polar epithelial MDCK II cells, prepared on a highly ordered porous substrate, were locally indented with the aim to unravel how the cytoskeleton and extracellular matrix (ECM) affects the viscoelasticity of such native membranes on a predefined length scale. We found a strong relation between the density and cross-linking of actin filaments and membrane stiffness.