Natural bioactive sericin-based hydrogel dressing for visual pH monitoring and infected wound therapy

Bacterial-infected wounds often lead to prolonged inflammation and delayed healing, posing a significant challenge in clinical practice. To address this issue, this study developed a novel antibacterial sericin-based hydrogel (rhein-sericin hydrogel, RHS) with inherent pH monitoring property based on natural active components. The hydrogel was engineered via crosslinking between sericin, isolated from silkworm cocoons, and rhein, resulting in a homogeneous gel structure. Experimental results demonstrated that the RHS hydrogel exhibits suitable mechanical properties, controllable biodegradability, and good biocompatibility. The hydrogel also displayed effective hemostatic performance, achieving a hemostasis time of 66 s in a mouse tail amputation model, significantly shorter than the 316 s recorded in the untreated control. In vitro antibacterial assays revealed that the RHS hydrogel possessed potent antibacterial activity, with bactericidal rates of 89.38% against E. coli, 94.9% against S. aureus, and 97.04% against MRSA. Furthermore, the hydrogel promoted HaCaT cell migration, achieving a migration rate of 64.48% at 24 h in a scratch wound assay. Notably, the hydrogel also displayed unique pH-responsive behavior, with the color varying according to pH changes, providing a visual indicator for real-time monitoring of wound status. In a S. aureus-infected wound model, the RHS hydrogel displayed outstanding antibacterial, anti-inflammatory, and pro-angiogenic capabilities, effectively modulating the wound microenvironment and promoting collagen deposition and re-epithelialization. After 12 days of treatment, the wound healing rate in the RHS group reached 97.71%, with near-complete wound closure. This study offers a promising strategy for the development of advanced hydrogel dressings based on natural components.