Systematical evolution on a Zn-Mg alloy potentially developed for biodegradable cardiovascular stents

To reduce the long-term side effects of permanent metallic stents, a new generation of cardiovascular stents called "biodegradable stents" is being extensively developed. Zinc has been considered as a promising candidate material for biodegradable cardiovascular stents due to its excellent biocompatibility and appropriate biodegradability. However, weak mechanical properties limit its further clinic application. In this study, hot extruded pure Zn and Zn-0.02 Mg alloy were prepared. Compared with pure Zn, Zn-0.02 Mg alloy showed more homogeneous microstructure, much smaller grain size and higher mechanical strength. Zn-0.02 Mg alloy presented uniform corrosion morphologies during the immersion process, and its corrosion rates was higher than that of pure Zn. Hemocompatibility results showed that the Zn-based alloy had extremely low hemolysis rate (0.74 ± 0.15%) and strong inhibitory effect on blood coagulation, platelet adhesion and aggregation. Zn-0.02 Mg alloy also exhibited excellent cytocompatibility. Its extracts could significantly promote the proliferation of endothelial cells. Moreover, the antibacterial activities of the Zn-based alloy were demonstrated by spread plate assay, live/dead viability assay and bacterial morphology observation. These results indicate that the extruded Zn-0.02 Mg alloy has a potential in biodegradable cardiovascular stents.