Photoinitiated Regulated Silver-Releasing Zwitterionic Hydrogel Coating for Antibacterial, Antifouling, and...

Blood-contacting catheters are susceptible to bacterial colonization, nonspecific protein adsorption, and thrombus adhesion, which may lead to catheter-related bloodstream infections and catheter dysfunction. To address these challenges, a photoinitiated silver-loaded zwitterionic hydrogel coating, denoted as pSBMA-A, was constructed on PVC catheter surfaces by integrating a PDA/BP interfacial layer, a poly-(sulfobetaine methacrylate) (pSBMA) hydrogel network, and silver nanoparticles (Ag NPs). The PDA/BP layer enhanced interfacial anchoring, while the pSBMA network provided a hydrated antifouling interface and served as a matrix for Ag NP incorporation. The small-sized Ag NPs (15.99 ± 0.11 nm) endowed the coating with broad-spectrum antibacterial activity. The pSBMA-A coating achieved antibacterial efficiencies of up to 99% against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli at a low Ag concentration of 0.05 mM. ICP-MS analysis showed that Ag was gradually released from the coating over 1-11 days, indicating regulated Ag release rather than rapid Ag loss. In addition, the pSBMA-containing coatings significantly improved surface hydrophilicity and reduced nonspecific BSA adsorption, supporting the antifouling role of the zwitterionic hydration layer. Compared with bare PVC, the pSBMA-A coating reduced thrombus adhesion by approximately 77% and showed acceptable hemocompatibility and cytocompatibility, with a hemolysis ratio below 2% and cell viability above 80%. Furthermore, subcutaneous implantation showed reduced inflammatory cell infiltration and lower IL-6 and CD68 expression around the pSBMA-A samples. This study provides a promising surface engineering strategy for improving the anti-infective, antifouling, and thrombus-resistant performance of blood-contacting PVC catheters.