A bioinspired long-acting chlorhexidine-eluting super-hydrophilic coating on vascular catheters prevents thrombosis and biofouling.

Thrombosis and biofouling represent two major complications associated with venous catheters, contributing to significant morbidity and mortality worldwide. Currently, anti-fouling coating strategies are one of the common approaches to address such issues. However, the existing anti-fouling coatings are limited by insufficient duration of efficacy. Herein, we propose a bioinspired, robust superhydrophilic polymer coating with long-acting chlorhexidine (CHX) elution for vascular catheters. This coating is fabricated via a stepwise surface chemical strategy: first, a CHX and dopamine (DA) assembly layer is deposited on the catheter surface; subsequently, polyallylamine (PAM) is employed to in situ chemically re-crosslink DA self-polymers in the CHX-DA film; finally, N-vinyl-2-pyrrolidone (NVP) is grafted onto the surface via free radical polymerization. The resulting composite coating shows super-hydrophilicity, thereby forming a highly hydrated shell that effectively prevents adhesion of bacteria, fibrinogen and platelets. Of particular importance is that the excellent integration of the compact PAM-crosslinked CHX-DA layer and the surface-hydrated shell effectively delays the release of CHX, thereby enabling sustained antimicrobial activity while minimizing CHX-induced cytotoxicity. In practical applications, the CHX-eluting super-hydrophilic coating provides durable antithrombotic and anti-infective functionality, indicating a promising strategy to address thrombosis and biofouling associated with venous catheters.