Importance of oxide film in endovascular biodegradable zinc stents

A better understanding of the surface oxide film on biodegradable metals could lead to the design of smarter, surface-responsive biodegradable stents with good biocompatibility and controlled degradation rates at different stages of implantation. In this study, the surface finish of zinc was manipulated through different material processing conditions, including oxidation, electropolishing and anodization. Implant wires with oxide films of varying surface characteristics were degraded in a living organism by using a rodent model to understand their response to a biological endovascular environment. It was found that the degradation rate was mainly dependent on the quality and stability of oxide film. Defects/cracks in the oxide film structure appear to serve as local corrosion sites, and their increased density accelerates the biocorrosion rate.