Influence of the Substrate Structure on the Nano-Mechanics of Focal Adhesion Points

The molecular structure of surfaces regulates the morphology and function of adherent cells. A research group with members from nano-sciences, physics cell biology and electron microscopy investigates the relevance of structural and biophysical properties of cell adhesion for motility, growth and differentiation of cells. The biochemical properties of proteins and other molecules as well as their arrangement or topography influences these cellular processes. We produce nano-structures by micro-contact printing and by AFM lithography. We investigate the effect of these nano-structures on the structure dynamics of the focal adhesion points and of the associated actin cytoskeleton. This knowledge is required to understand the influence of arrangement of the adhesion points and of adhesion switchable nano-structured surfaces. We measure the turn-over-dynamics of the fluorescently labelled actin cytoskeleton by TIR-microscopy. We measure additionally the mechanical properties of living cells by AFM and, in sub-cellular compartments, by micro-rheology. Electron microscopy is used to measure the three-dimensional structure of the cytoskeleton in the vicinity of the membrane. This structure is important for the interaction between the substrate, the focal adhesion points and the cytoskeleton and helps to understand better the differentiation and formation of tissues.