Dual-action MOF-on-MOF hydrogel: A chemo-photodynamic strategy for enhanced antibacterial activity and infected wound healing

Open skin wounds are susceptible to bacterial infections, which can delay healing and even trigger life-threatening complications. The improper and prolonged use of antibiotics can accelerate bacterial resistance, complicating the treatment of clinical infections. Therefore, there is an urgent need for effective antibiotic-free therapeutic strategies to treat bacterial infections in wounds. In this study, we loaded the growth factor Dimethyloxalylglycine (DMOG) into the pores of PCN-224 and subsequently deposited 2-Methylimidazole zinc salt (ZIF-8) on its surface, creating an injectable hydrogel based on a MOF-on-MOF design. This approach leverages metal ion release in conjunction with photodynamic therapy (PDT) to achieve effective antibacterial activity. Additionally, the injectable hydrogel can adapt to various wound morphologies and enable hemostasis for acute tissue injuries due to its fast gelation speed and adhesiveness. Meanwhile, the sustained release of DMOG promotes angiogenesis. Results demonstrated that the GelMA/HA/DMOG@PCN-224/ZIF-8 (GelMA/HA/D@PZ) hydrogel achieves a 99.9 % bactericidal rate against Staphylococcus aureus, Escherichia coli, and MRSA, while also significantly promoting the healing of infected wounds. Therefore, the GelMA/HA/D@PZ composite material facilitates initial hemostasis, mid-term antibacterial activity, and long-term angiogenesis, providing a novel, efficient, and safe approach to promote the healing of infected wounds.