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

Abstract

It is crucial to provide physical shield and moist environment for wound to accelerate healing. Herein, we establish a fine-tuned thermosensitive polymer hydrogel system (poly (ε-caprolactone-glycolide)-poly (ethylene glycol)-poly (ε-caprolactone-glycolide), PCGA-PEG-PCGA). By modulating the hydrophobic block length, a more stable gel phase is achieved, attributed to the increased exposure of hydrophobic regions , which facilitated the formation of a stronger hydrophobic channel. This system remains in a liquid state at room temperature, allowing for easy application, and transforms into a gel at physiological temperature, conforming to the wound site. The hydrogel demonstrate an excellent physical shield effect, as evidenced by the inhibition of bacterial growth in transwell experiments. Additionally, broad-spectrum antimicrobial silver nanoparticles (AgNPs) are incorporated as a non-antibiotic-dependent strategy to reduce the risk of infection. The addition of AgNPs don’t affect the gelation of copolymers. The antibacterial dressing (AgNPs/Gel) exhibit potent antibacterial effect in vitro. The in vivo experiments using full-thickness skin defect models i revealed that the AgNPs/Gel exhibit significant healing, as indicated by fewer inflammatory cells, increased collagen fiber deposition, and enhanced angiogenesis. The thermosensitive hydrogel with siver nanoparticles represents a promising antibacterial dressing for accelerating wound healing.