The two main classes of materials that we are investigating in cell studies, i.e. the very hydrophobic fluoropolymer and the very hydrophilic hydrogel, are, based on their wettability, not ideal to support cell growth; cells (e.g. fibroblasts) usually prefer materials with intermediate wettability. Indeed, on flat surfaces of the two materials cells hardly adhere and spread very little. However, topographic, “2.5D” patterns and 3D structures invoke marked cellular responses: cells align along micrometer grooves and spread on top of micrometer pillar structures. This behaviour is explained in terms of ‘contact guidance’.

We are investigating why the cells like to adhere to a certain (nano)topography and take the initial protein adsorption into consideration. We are employing several staining methods (based on antibodies) to visualise which proteins are accumulated on which parts of the surface structures, for example.

Besides the adsorption of proteins present in the cell culture medium, we are also interested to find out which proteins are produced by the cells; in response to the surface pattern. Thus, we perform real-time PCR to quantify the extra-cellular matrix (ECM) production.

Finally, we have recognised a strong dependence of the cell adhesion and spreading on the elasticity of the substrate. We are now systematically studying this effect; also considering the phenomenon of ‘durotaxis’.