Stable Dual-Functional Coating on Polyurethane Surface by Grafting Antibacterial-Zwitterionic Copolymer

Medical catheters face certain challenges in clinical treatment, such as bacterial biofilm adhesion and thrombus formation. Antifouling and antibacterial coatings have been proven to be an effective solution to diminish these undesirable events. Herein, we developed a facile and environmentally friendly strategy for constructing a dual-functional coating by grafting an antibacterial-zwitterionic copolymer onto polyurethane (PU) surfaces. The copolymer was designed and synthesized via a one-pot polymerization in an aqueous system by integrating 2-methacryloyloxyethyl phosphorylcholine (MPC), dimethyl diallyl ammonium chloride (DADMAC), and glycidyl methacrylate (GMA) as a functional monomer to enable surface immobilization. The resulting copolymer (PMDG) was robustly grafted onto a PU substrate pretreated with polydopamine/polyethylenimine (PDA/PEI) through a ring-opening reaction. The P/P-PMDG coating significantly improved the hydrophilicity of the surface, with the water contact angle (WCA) decreasing from 85.95° to 18.25°. Meanwhile, the coating demonstrated effective resistance to protein adsorption and bactericidal activity up to 99%, and such effects were well maintained after 4 weeks of immersion of the membrane in PBS solution, as well as after 3 cycles of reuse. Notably, the modified membranes exhibited excellent biocompatibility and hemocompatibility. This work provided a promising strategy for surface modification to improve biofouling and antibacterial efficiency of medical polymeric devices.