A new hydrogel to promote healing of bacteria infected wounds: Enzyme-like catalytic activity based on MnO₂ nanocrytal

Manganese dioxide (MnO₂) nanocrystal, a kind of nanomaterial with excellent enzyme-like catalytic properties, have been widely used in chemical, biological and pharmaceutical fields. It is composed of unique octahedral units that form a variety of tunnels and layered structures, which also lead to the emergence of different crystal forms and properties. In this study, different crystalline types of MnO₂ were synthesized by different methods, and different substrates were used to study MnO₂ catalytic ability of H₂O₂. β- MnO₂ nanocrystal had nearly 50% oxygen, among which adsorbed oxygen accounted for nearly 65%, so it exhibited the best catalytic performance and could promote oxidation catalytic reaction well. Furthermore, a functional MnO₂ hydrogel was prepared using β-MnO₂ as antibacterial agent and natural gelatin hydrogel as carrier. The antibacterial performance of the new hydrogel was further studied, and the survival rate of different species of bacteria was<5% after high concentration of MnO₂ functional hydrogel. In the end, MnO₂ functional hydrogel was applied to the wound treatment of mice infected with antibiotic resistant bacteria, and it was found that the wound healing rate of mice was nearly 100% on the 14th day, indicating that it had the potential of a new antibacterial dressing.