Enhanced selective cellular proliferation by multi-biofunctionalization of medical implant surfaces with heterodimeric BMP-2/6, fibronectin, and FGF-2.

Increasing cell adhesion on implant surfaces is an issue of high biomedical importance. Early colonization with endogenous cells reduces the risk of bacterial contamination and enhances the integration of an implant into the diverse cellular tissues surrounding it. In vivo integration of implants is controlled by a complex spatial and temporal interplay of cytokines and adhesive molecules. The concept of a multi-biofunctionalized TiO2 surface for stimulating bone and soft tissue growth is presented here. All supramolecular architectures were built with a biotin-streptavidin coupling system. Biofunctionalization of TiO2 with immobilized FGF-2 and heparin could be shown to selectively increase the proliferation of fibroblasts while immobilized BMP-2 only stimulated the growth of osteoblasts. Furthermore, TiO2 surfaces biofunctionalized with either the BMP-2 or BMP-2/6 growth factor and the cell adhesion-enhancing protein fibronectin showed higher osteoblast adhesion than a TiO2 surface functionalized with only one of these proteins. In conclusion, the presented immobilization strategy is applicable in vivo for a selective surface coating of implants in both hard and connective tissue. The combined immobilization of different extracellular proteins on implants has the potential to further influence cell-specific reactions.