Ultraviolet-induced Glycyrrhiza polysaccharide hydrogels with different mechanical strength for wound management

Glycyrrhiza polysaccharides possess excellent anti-inflammatory and antioxidant activities. Hydrogel dressing garnered remarkable efficacy in rejuvenating damaged skin, however, the impact of their mechanical strength on wound healing is still unclear. Herein, we reported Glycyrrhiza polysaccharides (GP)-dipotassium glycyrrhizinate (DG) (GPDG) hydrogels with different mechanical properties for tackling infected wounds. Neutral GP was extracted and purified from Glycyrrhiza inflata Bat., and its structural characteristics were exclusively confirmed. Next, GPDG hydrogels with low and high mechanical strength (low-GPDG and high-GPDG) were induced by UV crosslinking using Irgacure 2959 as photosensitizer. GPDG-based hydrogels could sustain DG release in the wound microenvironment. Furthermore, biocompatible GPDG hydrogels possessed robust antibacterial and cell proliferation-promotion bioactivities. When RAW264.7 cells were cultured on hydrogel scaffolds, the hard property of high-GPDG triggered excessive pro-inflammatory responses. On S. aureus-infected full-thickness skin wound test, low-GPDG demonstrated remarkable capacities in mitigating inflammatory infiltration, enhancing cell migration, facilitating macrophages M2 polarization and epithelialization, suppressing excessive collagen accumulation, which predominantly facilitated wound regeneration. In contrast, high-GPDG caused excessive inflammation and fibrosis in the wound, which was not beneficial for wound closure, ultimately resulting in apparent scars. Collectively, the study highlighted the significant role of soft GPDG hydrogels for the regenerative healing of infected wounds.