Corrosion behavior and hemocompatibility of a Cu(II)-incorporated polydopamine coating on biodegradable zinc

Zinc (Zn), as a new generation of biodegradable metallic materials, has attracted significant attention due to its moderate corrosion rate and acceptable biocompatibility. However, the low toxicity threshold of Zn²⁺ in the human body and the lack of anticoagulant properties pose great challenges for the practical application of biodegradable Zn. This study develops a polydopamine (PDA) functional coating incorporated with Cu(II) on pure Zn. Corrosion current density (i_corr) of the coated Zn shows a maximum reduction of over 60 % compared to bare Zn. The number of corrosion pits is reduced, and the localized corrosion of the Zn substrate is effectively mitigated, decreasing the risk of localized excessive Zn²⁺ release. The adhesion strength between the coating and the Zn substrate consistently achieves a 5B grade. Additionally, the PDA-Cu(II) coating exhibits good hemocompatibility and anticoagulant performances. As Cu content increasing, the number of platelet adhesion significantly decreases (by >78 %), and the blood coagulation index (BCI) shows substantial improvement, with a maximum increase of nearly 10 %. This research provides a feasible approach for exploring surface modifications of biodegradable Zn in applications of vascular stents.