Study On Modification Of Cu₂WS₄ Nanoenzyme And Its Antibacterial Properties

Bacterial infection is a serious threat to human health.Antibiotics are the most conventional and effective way to treat bacterial infection.However,the widespread use of antibiotics over the past few years has created a problem of bacterial resistance,which poses a great challenge to the traditional treatment of bacterial infections.Therefore,there is an urgent need for alternative treatments to fight bacterial infections.In response to these challenges,nano-enzyme materials with the function of enzyme simulation provide a new idea for the prevention and treatment of bacterial infection.Nanase is a type of nanomaterial that can catalyze the reaction of biologically associated substrates under mild conditions,has similar reaction kinetics to natural enzymes,and shows great potential as an effective antibacterial agent.Among many nano-enzyme materials,copper thiotungstate(Cu₂WS₄),as a typical terpolymer layered transition metal sulfide with a band gap of 1.74 e V,has attracted much attention due to its excellent properties such as adjustable component,variable structure and diverse morphology.To develop Cu-containing nano-enzyme,optimize its activity,reduce application concentration and improve application safety,Is considered an effective solution to the growing global crisis of antibiotic resistance.In this study,ethylene glycol was used as the solvent precursor to reduce copper bivalent in one step by regulating reaction conditions,and Cu₂WS₄ nano-enzyme material was prepared.The physical and chemical properties of Cu₂WS₄ were characterized in detail by XRD,SEM and other characterization methods.The antibacterial activity of Cu₂WS₄ nano-enzyme was evaluated by in vitro antibacterial and in vivo infected wound experiments.The characteristics of oxidase and peroxidase of Cu₂WS₄ nanase and the microcatalysis and antibacterial mechanism were investigated.The relationship between preparation method,spatial structure and catalytic performance of nano-enzymes with high antibacterial activity was revealed.Specific research contents are as follows:（1）Cu₂WS₄ nano-enzyme materials with polyhedral structure were successfully prepared by solvothermal method using the reductive property of ethylene glycol to reduce copper bivalent in one step,avoiding the problems of easy oxidation and high cost.The prepared Cu₂WS₄ nano-enzyme material has excellent crystallity and high thermal stability.It can achieve the maximum catalytic activity at 35℃and p H=4,and the catalytic substrate TMB changes color,showing high catalase-like and oxidase-like activities.（2）It was proved that Cu₂WS₄nano-enzyme material can catalyze H₂O₂ with biorelated concentration in the dark condition,showing excellent antibacterial performance for E.coli and S.aureus.The antibacterial concentration of Cu₂WS₄ on E.coli and S.aureus was 20μg/m L and 10μg/m L,respectively.The antibacterial rate reached 100%.The fluorescence staining of live/dead bacterial cells was consistent with the antibacterial test.The nano-enzyme material can also destroy the generated bacterial biofilm and inhibit the formation of new bacterial biofilm.The microscopic antibacterial mechanism was revealed through the detection experiment of active oxygen species:Cu₂WS₄ nano-enzyme material plays a leading role in catalyzing H₂O₂production·O^2-and·OH,thus achieving the purpose of antibacterial.（3）Using the mouse wound infection model,Cu₂WS₄ nano-enzyme material Band-aid was prepared for the anti-infection treatment of skin surface wounds,and the cytotoxicity test and organ pathological analysis were carried out.The results show that Cu₂WS₄ nano-enzyme material can effectively inhibit the growth of bacteria on the skin surface,promote the rapid wound healing,and has excellent biological safety.