NIR-Triggered Photothermal Nanocomposite Hydrogels Integrating Polydopamine Carbon Dots and Dynamic Multi-Networks for Infected Wound Healing

Accelerating the regeneration of infected wounds necessitates a multifaceted therapeutic intervention that simultaneously eradicates bacterial pathogens, adapts seamlessly to dynamic tissue deformations, and provides uninterrupted barrier protection, ultimately fostering a pro-healing microenvironment. To address these requirements, a dynamic multi-network nanocomposite hydrogel (OG/PCDs) was developed that couples on-demand photothermal therapy with orchestrated tissue remodeling. Specifically, polydopamine carbon dots (PDA-CDs) with exceptional near-infrared (NIR) photothermal conversion efficiency were initially synthesized as broad-spectrum antimicrobial agents. By combining intrinsic physical membrane disruption with NIR-triggered photothermal ablation, the PDA-CDs exhibit potent antibacterial activity while effectively mitigating the risk of bacterial resistance development. Subsequently, the OG/PCDs hydrogel was rationally engineered via the integration of dynamic Schiff base linkages, boronate ester bonds, and UV-triggered free-radical polymerization. Benefiting from its sophisticated architecture, the resulting hydrogel exhibited rapid autonomous self-healing capabilities, reliable tissue adhesion, and an intelligent pH-responsive release profile tailored for acidic infective microenvironments. Crucially, the hydrogel inherits the superior photothermal performance of PDA-CDs, enabling the efficient elimination of both planktonic bacteria and resilient biofilms. In vivo evaluations using an S. aureus-infected wound model demonstrated that the NIR-activated OG/PCDs hydrogel effectively sterilized the wound bed (>99% bacterial eradication) and significantly accelerated tissue remodeling, culminating in an impressive 98.42% wound closure rate over 14 days. Overall, by synergizing targeted photothermal antimicrobial efficacy with dynamic structural adaptability, the nanocomposite hydrogel presents a promising therapeutic platform to combat bacterial infections and facilitate tissue regeneration.