Enzyme-Mimetic Zwitterionic Microgel Coatings for Antifouling and Enhanced Antithrombosis

Blood-contacting devices serve as a mainstay in clinical treatment, yet thrombosis remains a major cause of device failure and poses risks to patient health. In this study, we developed a diselenide cross-linker, N,N'-bis(methacryloyl)selenocystamine (BMASC), incorporated into poly(sulfobetaine methacrylate) (PSBMA) microgels (defined as BSM) to create an enzyme-mimetic zwitterionic microgel coating (BSMC). The superhydrophilicity of PSBMA provides outstanding antifouling performance, while the diselenide bonds mimic the catalytic action of glutathione peroxidase (GPx) in generating nitric oxide (NO). The microgels are covalently anchored to substrates pretreated with polydopamine (PDA) and polyethylenimine (PEI) through an epoxy-amine ring-opening reaction. During the drying process, the interpenetrating PSBMA chains of the microgels diffuse, forming a dense and smooth hydrogel coating. The BSMC exhibits exceptional resistance to nonspecific adhesion of proteins, cells, and bacteria, with the synergistic effects of antifouling properties and NO effectively inhibiting platelet adhesion. Furthermore, rabbit blood circulation experiments demonstrate the superior antithrombotic efficacy of the BSMC. This coating holds promise as an effective solution to address the thrombus formation challenges of blood-contacting devices.