Preparation And Photothermal Antibacteria Of Cu_2-xS Nanocrystals

Metal sulfide is a very important semiconductor material with unique optical,electrical,magnetic,mechanical and catalytic properties.Among them,Cu2-xS nanocrystals have good photothermal performance due to strong local surface plasmon resonance(LSPR)effect and wide absorption spectrum.In this paper,a new method for the preparation of Cu7S4@PSIOAm nanorods with full solar spectrum(300-3300 nm)absorption and good biocompatibility was developed,and the photothermal properties of the synthesized nanorods were investigated The results show that nanorods have broad spectrum photothermal sterilization effect under solar irradation,which provides new materials and new methods for the area of photothermal sterilization.The main research progress is as follows:In this thesis,the Cu7S4 nanorods with uniform morphology and size were successfully controlled synthesized through improving experimental conditions such as reactant precursors and their ratio.by a solvothermal method.And water-soluble Cu7S4@PSIOAm,nanorods were prepared by surface modification of oleyl amine-modified polysuccinimide(PSIOAm)and Cu7S4@PSIOAm showed low toxicity and good biocompatibility.At the same time,Cu7S4@PSIOAm nanorods showed excellent near-infrared photothermal conversion efficiency(57.8%,808 nm).In addition,the temperature of the Cu7S4@PSIOAm aqueous solution at a concentration of 300 ?g/mL was increased from 25? to 80?after 4 min irradation of simulated solar light at an optical power density of 1.0 W/cm2.The bactericidal effect of Cu7S4@PSIOAm nanorods on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli under sunlight was further investigated.The bactericidal effect was examined by plate colony counting and fluorescence staining.The results showed that 75 ?g/mL Cu7S4?PSIOAm nanorods could achieve the complete killing of Gram-positive and negative bacteria when irradiated by the simulated sunlight at 1.0 W/cm2 for only 3 min.In addition,after the real sunlight(measured light power density of 70 mW/cm2)irradiation of 10 min,the two kinds of bacteria also obtained a complete killing effect.This method showed a good application prospects when it was not convenient to provide artificial light source at the field environment and resulting in using the nanorods fungicide for solar photothermal sterilization.In addition,the two representative bacteria were treated with direct heat treatment(70?,4 min)as a control but the sterilization effect was not sufficient,which indicating that excellent antibacterial effect of Cu7S4@PSIOAm nanorods may be derived from the synergistic effect of photothermal effect and solar light induced photocatalytic activity.