Evaluation of Biodegradability and Biocompatibility of Pure Zinc Coated with Zinc Phosphate for Cardiovascular Stent Applications

Purpose: Percutaneous coronary intervention is widely used as a primary treatment for cardiovascular diseases. In this regard, it has been revealed from studies that zinc is a potential material for use in stents due to its intrinsic physiological relevance, biocompatibility, biodegradability, and pro-regeneration properties. However, localized corrosion and burst release of zinc ions might cause an early implant failure and a risky environment for vascular remodeling. To resolve these drawbacks effectively, a coating of zinc phosphate on pure zinc was fabricated in this study using a microwave-assisted chemical conversion method. Methods: In this study, a comprehensive analysis was conducted through materials characterization, electrochemical testing, immersion testing, in vitro testing, and hemocompatibility evaluation to quantify the effect of zinc phosphate coating on zinc cardiovascular stents. Results: It is revealed that the microstructures of the coatings are mainly composed of zinc phosphate and sodium zinc phosphate. The presence of sodium zinc phosphate could improve corrosion behavior. The assessment of in vitro biocompatibility for the zinc phosphate coatings revealed satisfactory cell viability and a stable and smooth degradation surface for cell adhesion. Furthermore, the zinc phosphate coatings exhibited nonhemolytic properties and inhibitions to the adhesion of platelets. Conclusion: The zinc phosphate coatings could exhibit a uniform degradation behavior and a positive biological effect on vascular remodeling, and therefore, these coatings could be a promising surface treatment used in stent optimization for zinc.