Multifunctional MgF2/Polydopamine Coating on Mg Alloy for Vascular Stent Application

Mg alloy is of great potential in the application of vascular stent due to its degradation in physical environment and proper mechanical property. However its mechanical integrity does not meet the clinical requirement due to relatively fast degradation. Besides, in order to accelerate the re-endothelialization of Mg-based stents, it needs surface modification to improve the attachment, growth and adhesion of endothelial cells (ECs). To solve the main obstacles, an anti-corrosion and quick endothelialization coating was prepared on novel Mg-Zn-Y‒Nd alloy via a simple two-step immersion method in the present study, first in hydrofluoric acid (HF) then in dopamine tris-Hydrochloric acid (tris-HCl) solution. The coating was uniform and thin, which consisted of two layers-the upper was polydopamine (PDA) layer and the lower was MgF2 layer. The alloy with the coating demonstrated dramatic corrosion resistance enhancement in vitro by immersion test and electrochemical test. Moreover the HF-PDA-treated Mg alloy exhibited great performance of cell adhesion and proliferation. The coating created a favorable environment for ECs to have a competitive advantage over vascular smooth muscle cells (VSMCs), which was preferable for re-endothelialization. The results suggest that HF-PDA-treated Mg-Zn-Y‒Nd alloy has great potential in the application of vascular stent and the surface coating method is of great application value in biodegradable Mg alloy stent due to its simplicity and effectiveness.