Enhanced osteogenic response by collagen type I coating on surface-modified titanium bone implants

Surface modifications of titanium (Ti) bone implants can activate an osteogenic response and accelerate osseointegration after implantation. In this study, in vitro tests were performed to evaluate different titanium dioxide TiO2 modified surfaces, sandblasted, large grit, acid-etched implant surfaces and surfaces featuring nanotubular structures (nanopore diameters of 20 and 100 nm) produced through potentiostatic anodization before and after subjecting them to covalent treatment for functionalization and subsequent coating with collagen type I (Col I). The physicochemical and morphological properties were evaluated using spectroscopy and microscopy, which confirmed the structural and biochemical modifications of the surfaces after coating with Col I. Studies with pre-osteoblastic MC3T3-E1 cells indicate improved cell adhesion and proliferation on surfaces coated with Col I, whereas cell viability remained similar for all evaluated surfaces. The results of alkaline phosphatase expression and activity, as well as a mineralization assay, demonstrated that surfaces coated with Col I acted positively on the osteogenic differentiation of the cells in comparison with the non-coated surfaces. Our findings suggest that, regardless of the previous modification of the TiO2 surface, the addition of a Col I coating presents a promising modification for bone implant applications.