Endothelium-Inspired Structurally Enhanced Offensive–Defensive Coating for Combating Thrombosis and Biofouling

Thrombosis and bacterial infections pose critical challenges for blood-contacting implants, inducing serious morbidity and mortality. Inspired by the vascular endothelium, we present an eco-friendly and facile strategy to construct a structurally enhanced, integrated offensive–defensive coating with exceptional hemocompatibility, biocompatibility, and antibacterial activity. Hierarchical cobblestone-like micro/nanostructures are fabricated on the pyrolytic carbon via femtosecond laser ablation. Subsequently, copper ions (offensive component) are immobilized onto the structured surface through dopamine-mediated adhesion, enabling the catalytic generation of endogenous nitric oxide to actively interrupt the thrombosis cascade and bactericidal action by disrupting their membranes. Following this, a zwitterionic polymer is grafted onto the surface to form a hydration layer (defensive component), which passively inhibits the adhesion of biofoulants. The pre-engineered hierarchical structures effectively enhance copper ion loading capacity, stabilize the interfacial hydration layer, and simultaneously reduce the availability of anchoring sites for biofoulants. The resulting biomimetic coating exhibits excellent biocompatibility, with an ultralow hemolysis rate (0.1%, below ISO 10993-4 standards) and nearly 100% endothelial cell viability after 48 h of coincubation. It also demonstrates robust defensive performance, markedly reducing the adhesion of platelets (by 99.6%), fibrin (by 69.8%), and bacteria (by 99.1% for S. aureus and 95.5% for E. coli) compared to the pristine surface. Additionally, the coating achieves outstanding offensive functionality, with negligible platelet activation and high bactericidal efficiencies of 92.8% and 77.1% against S. aureus and E. coli, respectively. This endothelium-mimicking, drug-free strategy provides a versatile platform for durable, biocompatible cardiovascular implants, potentially reducing clinical complications and improving patient outcomes.