Bioinspired Catalytic NO-Releasing Coating on Magnesium-Based Vascular Stents: Corrosion Resistance and Multifunctional Bioactivity

Abstract

A PTMC coating with the embedding of polyphenols/ebselen was proposed to construct on the AZ31 alloy, with the aim of surface modification on cardiovascular stents. Ebselen (Ebs) can endow the coating with the ability of catalytically releasing nitric oxide while polyphenols impart stable corrosion resistance to the coating by complexing with metal ions. In vitro corrosion resistance tests showed that icorr of AZ31-P/2.5% Ebs (8.91 × 10−8 A/cm2) is two orders of magnitude lower than that of AZ31 (6.16 × 10−6 A/cm2). During the 10-day immersion in PBS, the impedance modulus value of AZ31-P/2.5%Ebs was consistently higher than that of the other samples. AZ31-P/1%Ebs coating released least amount of H2 (0.315 mL) and the pH value (∼7.5) maintained almost constant during the 360 hours immersion. During a 30-day immersion, the NO catalytic release rates of AZ31-P/2.5%Ebs remained within the range of 3.5-0.9&cenveo_unknown_entity_wingdings2_F0CD;10−10 mol/cm2/min. The biological evaluation results showed that the AZ31-P/2.5%Ebs exhibits anticoagulant, endothelial cell growth promotion and smooth muscle proliferation inhibition functions. This coating strategy effectively slowed down the degradation rate of the magnesium substrate, and achieved multiple functions, which is of great significance for the surface design of magnesium-based vascular stents.