NIR-Responsive Nano-Photothermal and Antioxidant Platforms for Combating Bacteria
Multidrug-resistant (MDR) bacterial infections demand safe, high-efficacy alternatives to antibiotics. This study develops an acid-sensitive dynamic nanocomposite hydrogel (ACP@Ag/OC) incorporating metal-based nanoparticles for combined photothermal and antioxidant antibacterial action. The hydrogel achieves a photothermal conversion efficiency of 29.4% and near-complete reactive oxygen species (ROS) scavenging across all tested models. In vitro, ACP@Ag/OC inhibits Escherichia coli and Staphylococcus aureus by 60% and 57%, respectively; under near-infrared (NIR) irradiation, antibacterial efficacy increases 1.7-fold for both strains. Polydopamine (PDA) incorporation confers exceptional adhesion, maintaining performance under strong water currents. Hemolysis assays confirm negligible cytotoxicity and excellent blood compatibility. The platform addresses key limitations of silver nanoparticles—aggregation and poor biocompatibility—by embedding them within a dynamic hydrogel network. Mechanical testing demonstrates superior strength, self-healing, and adaptability to dynamic environments, effectively sealing wounds. These results position ACP@Ag/OC as a promising tissue adhesive and wound healing patch, with potential for personalized modular functionalization via catechol and amine chemistry. The work provides a translational pathway for combating MDR infections through NIR-triggered photothermal therapy combined with antioxidant protection.