Enhancing the integrity of a nanostructured oxide coating on super-elastic nickel-titanium stents for vascular applications

A nanostructured oxide coating was created in situ on a medical-grade, super-elastic nickel-titanium ("nitinol") alloy by anodization. The substrate is a vascular stent, and a carefully designed electrochemical geometry creates a uniform coating on all three dimensions. To preserve the integrity of the coating during the extreme stresses encountered during the packaging and deployment of the stent, the coating thickness must be limited to -500 nm, and a moderate temperature annealing step is employed. Endothelial cell migration on this surface failed to demonstrate an enhanced biological response. Subsequent surface analysis using X-ray Photoelectron Spectroscopy (XPS) revealed the presence of nickel on this surface.