Spraying‐assisted layer‐by‐layer assembled coatings with dual self‐healing ability to resist degradation and enhance endothelialization of ZE21B alloys for vascular stents

Abstract Drug‐eluting magnesium (Mg) alloy stents have a slower degradation rate and lower restenosis rate compared with uncoated stents, demonstrating good clinical efficacy. However, the release of anti‐hyperplasia drugs from coatings delays endothelial tissue repair, thus leading to late stent thrombosis. To address these issues, a dual self‐healed coating with various biological properties was fabricated on magnesium fluoride/polydopamine (MgF 2 /PDA)‐treated Mg alloys by spraying‐assisted layer‐by‐layer (LBL) self‐assembly of chitosan (CS), gallic acid (GA), and 3‐aminobenzeneboronic acid‐modified hyaluronic acid (HA‐ABBA). The LBL coating, approximately 1.50 μm thick, exhibited a uniform morphology with good adhesion strength (~ 1065 mN). The annual corrosion rate ( P i ) of LBL samples was ~ 1400 times slower than that of the Mg substrate, due to the physical barrier function provided by MgF 2 /PDA layers and the dual self‐healed ability of LBL layers. The rapid self‐healing ability (with a healing period of ~ 4 h under dynamic/static conditions) resulted from the synergistic interplay between the recombination of diverse chemical bonds within the LBL coating and the coordination of LBL‐released GA with Mg 2+ , as corroborated by computer simulations. Compared with the drug‐eluting coatings, the LBL sample demonstrated substantial advantages in anti‐oxidation, anti‐denaturation of fibrinogen, anti‐platelet adhesion, anti‐inflammation, anti‐hyperplasia, and promoted‐endothelialization. These benefits effectively address the limitations associated with drug‐eluting coatings.