Preparation And Synergistic Antibacterial Properties Of Novel Bismuth-based Nanocomposites

The emergence of multi-drug resistant strains of bacteria poses a serious threat to global public health due to the misuse of antibiotics.Drug-resistant bacteria cause persistent bacterial infections that are recurrent,persistent,and have high mortality rates.In addition,the development of new antibiotics has been slow,and it is important to investigate the design of antibiotic-independent treatments to overcome the problem of bacterial resistance in order to better protect the effectiveness of existing antibiotics.Photothermal therapy(PTT)is a promising treatment method.Bi₂S₃ in bismuth-based materials is often used as a PTT therapeutic agent and has gained widespread attention for its good biocompatibility,low cost,biodegradability,high stability and no significant side effects.PTT therapeutic agents can generate heat under near-infrared(NIR)laser irradiation,and the high temperature can damage bacteria.However,it is difficult to obtain satisfactory antimicrobial effects with a single PTT modality using only Bi₂S₃ materials,and the integration of PTT and chemodynamic therapy(CDT)is a prospective approach to improve antimicrobial efficiency.Copper-based nanomaterials are an important chemodynamic therapeutic agent,in which Cu₂Se nanomaterials possess peroxidase activity and can catalyze the Fenton reaction,in which Cu⁺ions react with endogenous hydrogen peroxide(H₂O₂)to generate highly toxic hydroxyl radicals(·OH).The Fenton reaction is a major strategy for chemical kinetic therapy(CDT),and the Fenton reaction rate of Cu-based materials is about 160 times faster than that of conventional Fe-based materials in a mild acidic microenvironment..Once CDT is combined with PTT,the membrane will have improved sensitivity to heat and permeability in the compromised state,which not only can effectively shorten the treatment time but also reduce the side effects associated with PTT.We use the bismuth-based material Bi₂S₃ as a substrate and composite with Cu₂Se to improve the near-infrared absorption of bismuth-based composites and increase the photothermal conversion efficiency,while triggering a synergistic effect to effectively kill bacteria without drug resistance.In this study,we successfully constructed Cu₂Se@Bi₂S₃ nanocomposite and used it as a combined CDT and PTT therapeutic agent.We investigated the basic morphology,compositional composition,and surface charge of Cu₂Se@Bi₂S₃ by SEM,TEM,zeta potential,XPS,and XRD characterization;the peroxidase properties of Cu₂Se@Bi₂S₃ by TMB method;the photothermal properties of Cu₂Se@Bi₂S₃ by warming performance and calculation of photothermal conversion efficiency,in addition we investigated In addition,we investigated the redox process of Cu₂Se@Bi₂S₃ on the antioxidant glutathione(GSH).In the study of antibacterial properties of Cu₂Se@Bi₂S₃,Cu₂Se@Bi₂S₃ showed good antibacterial efficiency against Escherichia coli and Staphylococcus aureus.Therapeutic concentrations of Cu₂Se@Bi₂S₃ were almost non-cytotoxic and could effectively promote wound anti-inflammation and healing in an acute wound model experiment in mice.