Improved the deposition rate of polydopamine on the biodegradable pure Zn via ZnO coating for cardiovascular stent application

Abstract

Metal zinc due to its rapid degradation rate and good absorption in the body is suitable for the clinical requirements of cardiovascular stents. Biomimetic polydopamine (PDA) as a high-efficient surface coating can adhere to Zn substrate tightly, improving the biocompatibility of zinc biodegradable cardiovascular sent. However, traditional PDA deposition method requires accurate pH and long immersion time, resulting in a low growth rate of coating. Herein, ZnO layers coat on the Zn surface, which produces the transition from the valence band to conduction band under UV irridation (UVZnO). Forming of photo-induced electron-hole (e−-h+) pair generates transfer energy, which can catalyze H2O and O2 to produce active oxygen species (ROS). The abundant ROS accelerates the deposition of PDA on Zn substrate, which shortens the polymerization time to 30 min at pH 8.5. The polymerization rate of PDA increases about two orders of magnitude. ZnO nano-layer can control the release of Zn2+ ions, which enhances endothelial cells (ECs) proliferation. It is promising to improve the re-endothelialization and avoid re-stenosis in sent and neointimal hyperplasia. In addition, the UVZnO/PDA/PLGA layer increases the corrosion resistance of Zn substrate after long-term immersion. The Zn/UVZnO/PDA/PLGA is promising for the treatment of cardiovascular diseases.