Fabrication of Zwitterionic Copolymer and Ag Nanoparticle Coating for Enhanced Antibiofouling and Bactericidal Properties

Titanium (Ti) implants face significant challenges due to bacterial infections and thrombosis caused by surface biofouling, often leading to implantation failure. Hence, we developed an accelerated codeposition strategy to functionalize Ti surfaces with zwitterionic poly(sulfobetaine methacrylate) (PSBMA) and silver nanoparticles (AgNPs) for enhanced antibiofouling and antibacterial properties. In this approach, AgNO3 served a dual role: (1) as an oxidant to accelerate dopamine polymerization and PSBMA codeposition, reducing reaction time from 24 to 4 h and (2) as a precursor for in situ synthesis of uniformly distributed AgNPs via phenolic hydroxyl reduction. The optimized Ti/PDA–PSB@Ag0.15 coating exhibited superior and robust antibacterial performance, achieving >99.9% inhibition against both E. coli and S. aureus, while the cytotoxicity assays confirmed high L929 fibroblast viability (>90%), ensuring biosafety. In addition, the zwitterionic polymer contained in the Ti/PDA–PSB@Ag0.15 coating provided superhydrophilicity and outstanding protein resistance, reducing 85% of both bovine fibrinogen (BFG) and bovine serum albumin (BSA) adsorption compared to unmodified Ti. Finally, the modified Ti substrates demonstrated minimal hemolysis ratio (<3%), reduced platelet adhesion, and prolonged activated partial thromboplastin time (APTT), indicating excellent hemocompatibility and strong anticoagulant properties. Thus, this work presents a rapid, scalable method to engineer multifunctional Ti implants with synergistic antifouling and bactericidal capabilities, offering significant potential for clinical applications in orthopedic, dental, and cardiovascular devices.