Effect of a gold–palladium coating on the long-term adhesion of human osteoblasts on biocompatible metallic materials

Our ambition for several years is to study the in vitro interface between human bone cells and biomedical metals in order to improve dental and orthopaedic implant's surface. The long-term adhesion of human osteoblasts cultured on pure titanium, titanium alloy and stainless steel substrates presenting 4 different surface morphologies and 2 different roughness amplitudes (obtained by sand-blasting, acid-etching, electro-erosion and polishing) was quantified from 24 h to 21 days. The half part of the samples was sputter-coated with gold–palladium. The coating by a nanometric gold–palladium layer influenced differently the long-term adhesion of human osteoblasts as a function of the composition of the substrate. This influence was either positive, neutral or negative but was significantly demonstrated only three times. In all the three cases, the coating improved the long-term adhesion of osteoblasts. Consequently, it appears that a gold–palladium coating could be a good way to improve cell adhesion, and perhaps tissue adhesion, on metallic surfaces with low biocompatibility like polished stainless steel substrates or acid-etched pure titanium substrates.