A fine-tuned thermosensitive hydrogel for wound reparation via phase transition offering excellent antibacterial activity†

It is crucial to provide a physical shield and moist environment for accelerated wound healing. Herein, we developed a fine-tuned thermosensitive polymer hydrogel system (poly(ε-caprolactone-glycolide)–poly(ethylene glycol)–poly(ε-caprolactone-glycolide), PCGA–PEG–PCGA) to serve as a shield for wound repair. By modulating the hydrophobic block length, a more stable gel phase was achieved owing to the increased exposure to hydrophobic regions, which facilitated the formation of stronger hydrophobic channels. This system remained in a liquid state at room temperature, allowing for easy application, and transformed into a gel at physiological temperature, conforming to the wound site. The hydrogel demonstrated an excellent physical shielding effect, as evidenced by the inhibition of bacterial growth in transwell experiments. Additionally, broad-spectrum antimicrobial silver nanoparticles (AgNPs) were incorporated following a non-antibiotic-dependent strategy to reduce the risk of infection. The addition of AgNPs did not affect the gelation of the copolymers. The antibacterial dressing (AgNPs/Gel) exhibited a potent antibacterial effect in vitro. In vivo experiments using full-thickness skin defect models revealed that AgNPs/Gel exhibited significant healing, as indicated by fewer inflammatory cells, increased collagen fiber deposition, and enhanced angiogenesis. The thermosensitive hydrogel containing silver nanoparticles is a promising antibacterial dressing for accelerating wound healing.