Dopamine-mediated natural hydrogel coating with Cu²⁺ and Ag nanoparticles for multifunctional polyurethane biointerfaces

A natural hydrogel coating confers multifunctionality to polyurethane biointerfaces. • The synergy of CMCS and AgNPs endowed robust, long-lasting antibacterial action. • NO catalytically released by Cu²⁺ enabled superior pro-endothelialization performance. Despite its favorable mechanical properties, the clinical application of polyurethane (PU) in cardiovascular implants is severely limited by surface hydrophobicity, poor hemocompatibility, and insufficient antibacterial and pro-endothelialization functions. To overcome these limitations, we report a robust natural hydrogel coating (PU-Gel/Cu/Ag) with integrated anticoagulant and antibacterial functionalities, fabricated through the initial deposition of a polydopamine (PDA) covalent anchoring layer on polyurethane, followed by the grafting of a carboxymethyl chitosan (CMCS)/sodium alginate (SA) composite co-loaded with copper ions (Cu²⁺) and silver nanoparticles (AgNPs). A substantial decrease in water contact angle was observed for the coated PU, confirming that the coating markedly improved surface hydrophilicity. In addition, a substantial reduction in hemolysis ratio and fibrinogen adsorption was achieved with the coating, along with potent inhibition of platelet adhesion and activation, which together underscore its outstanding anticoagulant properties. Moreover, cell assays confirmed that the coating not only significantly enhanced endothelial cell (EC) attachment, expansion, and VEGF/NO expression, but also dramatically suppressed smooth muscle cell (SMC) adhesion and proliferation, highlighting its excellent pro-endothelialization and anti-intimal hyperplasia performance. Owing to the intrinsic cationic antibacterial property of carboxymethyl chitosan, combined with the synergistic action of AgNPs, the as-prepared coating demonstrated potent and sustained antimicrobial action that effectively suppressed both Gram-positive S. aureus and Gram-negative E. coli. The coating-incorporated Cu²⁺ acted as a durable catalyst that continuously drove NO production from endogenous donors, thereby synergistically augmenting both anticoagulation and pro-endothelialization. This study establishes a new paradigm for the design of multicomponent synergistic coatings, in which the coexistence of Cu²⁺ and AgNPs within a natural hydrogel matrix enables the synergistic regulation of surface wettability, catalytic NO release, and multi-target antibacterial action. This integrated approach fundamentally overcomes the limitations of previously reported single- or dual-functional coatings, offering a broadly applicable and translatable strategy for surface engineering of cardiovascular implant materials. Download: Download high-res image (228KB) Download: Download full-size image