A Double Network Composite Hydrogel with Self-Regulating Cu2+/Luteolin Release and Mechanical Modulation for Enhanced Wound Healing

Designing adaptive and smart hydrogel wound dressings to meet specific needs across different stages of wound healing is crucial. Here, we present a composite hydrogel, GSC/PBE@Lut, that offers self-regulating release of cupric ions and luteolin and modulates mechanical properties to promote chronic wound healing. The double network hydrogel, GSC, is fabricated through photo-cross-linking of gelatin methacrylate, followed by Cu2+-alginate coordination cross-linking. On one hand, GSC allows for rapid Cu2+ release to eliminate bacteria in the acidic pH environment during inflammation and reduces the hydrogel's mechanical strength to minimize tissue trauma during early dressing changes. On the other hand, GSC enables slow Cu2+ release during the proliferation stage, promoting angiogenesis and biocompatibility. Furthermore, the inclusion of pH- and reactive oxygen species (ROS)-responsive luteolin nanoparticles (PBE@Lut) in the hydrogel matrix allows for controlled release of luteolin, offering antioxidant and anti-inflammatory effects and promoting anti-inflammatory macrophage polarization. In a murine model of Staphylococcus aureus infected wounds, GSC/PBE@Lut demonstrates exceptional therapeutic benefits in antibacterial, anti-inflammatory, angiogenic, and tissue regeneration. Overall, our results suggest that smart hydrogels with controlled bioactive agent release and mechanical modulation present a promising solution for treating chronic wounds.