Preparation And Performance Study Of TeSe Nanomaterials

In recent years,antibiotics have been the main clinical treatment for bacterial infections,but the overuse of antibiotics has led to the development of severe bacterial drug resistance.Tellurium nanomaterials have been reported to disrupt the thiol structure in bacterial cells and have good photothermal and photodynamic properties in response to stimulation at appropriate wavelengths.Based on the above reasons,a feathery tellurium selenide heterostructured nanomaterial（TeSe）was designed and prepared in this thesis,and loaded with the photosensitizer indocyanine green（ICG）by electrostatic adsorption to construct a multifunctional antibacterial therapeutic platform with synergistic effects of photothermal therapy（PTT）and photodynamic therapy（PDT）,and further explore its application potential in the treatment of bacterial infections.The main research components are as follows.1.Preparation and characterization of TeSe nanomaterials.Feather-like TeSe nanomaterials were prepared by hydrothermal method using sodium selenite（Na₂Se O₃）and sodium tellurite（Na₂Te O₃）as precursors,polyethylene glycol（PEG）of different molecular weights as surfactants,and glutathione（GSH）as reducing agent.A series of characterizations of the samples were performed by transmission electron microscopy（TEM）,X-ray diffraction analysis（XRD）,X-ray photoelectron spectroscopy（XPS）,and energy dispersive X-ray spectroscopy（EDS）.The results show that the TeSe nanomaterials prepared by this method are well dispersed and homogeneous in size,about 190～200 nm.2.Construction of the TeSe-ICG nanoplatform.The TeSe nanomaterials were loaded with ICG by electrostatic adsorption to enhance its photothermal and photodynamic synergistic therapeutic effects.The loading of ICG was calculated by ultraviolet-visible spectrophotometer（UV-vis）and the photothermal and photodynamic properties of the TeSe-ICG nanomaterials were evaluated.The results showed that the TeSe-ICG nanomaterials have good photothermal conversion efficiency and single-linear oxygen（¹O₂）production under 808 nm NIR stimulation.3.Antibacterial properties of the TeSe-ICG nanoplatform were investigated.The in vitro antibacterial effect of the TeSe-ICG nanomaterials was evaluated by Gram-negative bacterium Escherichia coli（E.coli）and Gram-positive bacterium Staphylococcus aureus（S.aureus）.The in vivo antimicrobial effect of the TeSe-ICG nanomaterials was evaluated by establishing a mouse trauma infection model.In vitro antibacterial experiments showed that the TeSe-ICG nanomaterials were effective in photocide against both Gram-negative and Gram-positive bacteria under near-infrared laser irradiation,and the bactericidal rates were above 99%.In vivo antibacterial experiments in mice showed that the TeSe-ICG nanomaterials also had good therapeutic effects on inhibiting wound infection and promoting wound healing in mice,and the wound healing rate reached 98.1%after 10 days of treatment.In conclusion,the TeSe-ICG nanomaterials have a good effect of synergistic antibacterial by photothermal and photodynamic,which provides a promising strategy for the treatment of bacterial infections.