Photothermal antimicrobial guar gum hydrogel cross-linked by bioactive small molecule lysine for infected wound healing.

The healing of bacteria-infected wounds has long posed a significant clinical challenge. Traditional hydrogel wound dressings often lack self-healing properties and effective antibacterial characteristics, making wound healing difficult. In this study, a bioactive small molecule cross-linking agent 4-FPBA/Lys/4-FPBA (FLF) composed of 4-formylphenylboronic acid (4-FPBA) and lysine (Lys) was utilized to cross-link guar gum (GG) and a tannic acid/iron (TA/Fe) chelate through multiple dynamic bonds, leading to the formation of a novel self-healing hydrogel dressing GG-FLF/TA/Fe. The hydrogel exhibited excellent stretchability and self-healing ability, which enabled it to adapt to irregular wound sites. Meanwhile, the hydrogel demonstrated remarkable antibacterial efficacy (>99 %) facilitated by the synergistic effects of photothermal properties and aromatic Schiff bases. Additionally, it had adjustable rheological properties, good mechanical characteristics, conductivity, antioxidant characteristics and biocompatibility. Notably, the GG-FLF/TA/Fe hydrogel dressing irradiated with NIR displayed superior therapeutic effects in a mouse wound infection model (wound healing rate: 94.8 %), promoting recovery from bacterially infected wounds by enhancing collagen deposition, facilitating the formation of skin appendages and blood vessels, and regulating inflammatory factors. In summary, this study presented a novel approach to prepare biologically active antibacterial polysaccharide hydrogels and highlighted the substantial potential of this hydrogel as a biomedical antibacterial dressing.