Impact of RGD micro-patterns on cell adhesion

In order to avoid the problems related to biomaterial use (inflammation, infections, aseptic loosening, etc.), a new approach consisting of associating the material and autologous cells before implantation is being developed, thus requiring a perfect cooperation between the material's surface and the cell. To improve cell adhesion to biomaterials, a suitable method is to functionalize their surface by pro-adhesive ligand grafting. The aim of this study was to covalently graft RGD containing peptides onto a poly-(ethylene terephthalate) surface in well-defined microstructures in order to control MC3T3 cell adhesion. We followed two different routes for obtaining micro-patterned materials: (1) a photoablation technique using an excimer laser and (2) a photolithography process. The resulting patterns were characterized by optical microscopy, scanning electron microscopy, optical profilometry and high resolution μ-imager. The biological evaluation of cell adhesion onto the micro-patterned surfaces was carried out using optical microscopy, scanning electron microscopy and fluorescence microscopy. Cells seeded onto photolithographical or photoablated micro-patterned PET exhibited an alignment with the RGD domains and appear to be connecting through pseudopods extending towards each other. Whatever the technique used to create micro-patterns, a cell alignment occurs once the thickness of the RGD line reaches ∼100 μm. These results prove the importance of microstructured surfaces for the elaboration of tissue engineered biomaterials.