One-pot constructed tannic acid/chitosan/heparin hybrid coating on magnesium alloy toward integrated anticorrosion, antithrombosis, endothelialization and antibacterial performance for vascular stent application.

Magnesium alloys are promising for bioresorbable cardiovascular stents but suffer from rapid corrosion, thrombosis, intimal hyperplasia, and bacterial infection. Herein, a one-pot method was developed to fabricate tannic acid/chitosan/heparin (TA/CS/Hep) hybrid coatings on magnesium alloys. Tuning the component ratio yielded a bio-interface integrating anti-corrosion, anticoagulation, antibacterial ability, and selective cell regulation. Our results demonstrate that the one-step co-deposition method enables uniform loading of TA, CS, and Hep, producing a dense and homogeneous coating with favorable adhesion on the magnesium alloy (MA) surface. The obtained coating not only exhibits superior hydrophilicity but also markedly improves the corrosion resistance of the MA, effectively suppressing rapid degradation of the substrate. Biocompatibility evaluations reveal that the as-prepared hybrid coating significantly reduces platelet attachment and activation, decreases fibrinogen adsorption, and lowers the occurrence of hemolysis to below 3%, displaying obviously enhanced anticoagulant properties. Moreover, the coating promotes the attachment, differentiation, and functional expression of endothelial cells (ECs) while preventing the growth of smooth muscle cells (SMCs), demonstrating a better pro-endothelialization capability. Owing to the synergistic antibacterial activities of chitosan and tannic acid, the coating exerts powerful inhibitory effects on Staphylococcus aureus and Escherichia coli, with antibacterial rates ranging from 96% to 100%. When the weight ratio of TA/CS/Hep is 2:1:3, the modified MA exhibits balanced overall performance, achieving synergy among corrosion resistance, anticoagulation, endothelial promotion, hyperplasia inhibition, and antibacterial function. The present study offers a simple, green, and efficient strategy for the multifunctional surface modification of magnesium-based biodegradable cardiovascular implant materials.