Controlled Nitric Oxide-Releasing Nanovehicles for Enhanced Infected Wound Healing: A Study on PDA@BNN6 Encapsulated in GelMA Hydrogel

The photo-activated thermo/gas antimicrobial nanocomposite hydrogel, Gel/PDA@BNN6, is composed of the nitric oxide (NO) carrier N, N'-di-sec-butyl-N, N'-dinitroso-p-phenylenediamine (BNN6), photothermal (PTT) material polydopamine nanoparticles (PDA NPs), and methacrylate gelatin (GelMA). This hydrogel can release NO gas in a stable and controlled manner, generating a localized photothermal effect when exposed to near-infrared laser light. This dual action promotes the healing of full-thickness skin wounds that are infected. Gel/PDA@BNN6 was developed, and both in vitro and in vivo experiments were carried out to evaluate its structure, physicochemical properties, antibacterial effects, effectiveness in promoting infected wound healing, and biocompatibility. Gel/PDA@BNN6 was successfully synthesized, exhibiting a porous three-dimensional lattice structure and excellent mechanical properties. It demonstrated highly efficient photothermal conversion, controllable nitric oxide delivery, strong bactericidal effects, and minimal cytotoxicity in vitro. In vivo, Gel/PDA@BNN6, when used with NIR therapy, showed significant anti-inflammatory effects, promoted collagen deposition, and stimulated vascular neoangiogenesis, which accelerated wound closure. Additionally, it displayed superior biocompatibility. Gel/PDA@BNN6 has shown an explicit curative effect for infected wound healing, suggesting it has a good chance of being an antimicrobial dressing in the future.