A mechanically reinforced double-network hydrogel with sustained SaB release and synergistic photothermal therapy for enhanced wound healing.

The complex wound microenvironment makes wound healing difficult. This requires dressings to not only possess excellent mechanical properties to provide physical support for wound healing but also to have multiple biological functions that can respond to the different stages of the wound and promote healing. This study reports a multifunctional dual-network hydrogel (PPGel-BP/SaB) material designed to meet the needs of wound healing. This hydrogel was prepared by using norbornyl to modify polyhedral polysiloxane-polyethylene glycol (POSS-PEG-OH) via an esterification reaction, yielding a norbornyl-functionalized monomer (POSS-PEG-NB), which was then combined with a four-arm polyethylene glycol-type maleimide, HS-PEG-SH, to form a dual network, with black phosphorus (BP) nanosheets and salvianolic acid B (SaB) loaded within it. Rheological analysis revealed that the dual-network hydrogel exhibits superior mechanical properties compared to the single-network hydrogel. In vitro degradation experiments demonstrated that the degradation rate of this hydrogel can be adjusted by controlling the solid content to meet the requirements of wound healing. In vitro studies indicate that the PPGel-BP/SaB hydrogel not only exhibits photothermal effects but also demonstrates nearly 100% antibacterial efficacy under near-infrared (NIR) irradiation, along with potent ROS scavenging activity. In vivo studies indicate that this hydrogel has the ability to suppress inflammation, scavenge oxidative stress, and promote collagen deposition and cell proliferation. Overall, this study proposes a multifunctional dressing that combines mechanical strength with photothermal effects, antioxidant activity, antibacterial properties, and wound-healing capabilities, offering a new approach to wound repair.