Bio-tribological properties and cytocompatibility of Ti-Si-N coatings

Ti-Si-N coatings are synthesized on titanium alloy (Ti6Al4V) by arc-enhanced magnetron sputtering and the microstructure and tribological properties are determined. The friction coefficient of the Ti-Si-N coatings, which is smaller in human serum than ambient air, decreases gradually with Si contents. Protein gel electrophoresis shows that the small friction coefficient is due to adsorbed proteins from the human serum under sliding conditions. The cytocompatibility of the coatings is assessed in vitro by a relative nitrite assay. The Ti-Si-N coatings have a positive effect on nitric oxide synthesis on the endothelial cells. The cell morphology and spreading on the coatings are examined by fluorescence staining. The Ti-Si-N coating with 12 at% Si exhibits the best effects in promoting actin cytoskeleton formation and cell spreading compared to coatings with different Si contents and titanium alloy.