Superior toughness Anticorrosion-Bioactive integrated multilayer coating with excellent adhesion for biodegradable Magnesium-Based stents

Biodegradable magnesium-based stents overcome the limitations of non-degradable stents and exhibit superior mechanical properties compared to biodegradable polymer counterparts, representing an inevitable trend in cardiovascular stent evolution. However, the excessively rapid degradation rate remains a pivotal factor that constrains their clinical application. In this work, an anticorrosion-bioactive integrated multilayer coating is developed for magnesium-based stents. By optimizing the molecular structure of poly(L-lactide-co-omega-caprolactone) (PLCL), a biodegradable coating material with excellent mechanical properties and effective barrier performance is obtained. To enhance the wettability and adhesion strength between the highly surface-energy magnesium and the low-polarity PLCL, a silane-based transition layer and an intermediate connecting layer of covalently bonded PLCL chains are sequentially constructed on the magnesium substrate. Furthermore, bioactive polymer brush consists of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and Arg-Glu-Asp-Val (REDV) peptide is fabricated on the PLCL anticorrosion coating. The combined in vitro and in vivo experiments confirm that the multilayer coating exhibits commendable anti-corrosion performance, and is beneficial to anticoagulation and endothelialization, thereby making the degradation process of magnesium-based stents more compatible with the vascular remodeling process. The anticorrosion-bioactive multilayer composite coating developed in this study has the potential to overcome the corrosion resistance limitations of magnesium-based implants, thus promoting their clinical application.