Study On The Preparation And Antibacterial Properties Of Carbon-based Nanocomposites

Infectious diseases caused by microbial infections have become an extremely serious global threat to human health.In real life,bacterial infection may cause some serious diseases,such as lung disease,hemolytic anemia,pseudomembranous colitis,sepsis,pericarditis,acute renal failure,etc.The use of traditional antibiotics to control the growth and proliferation of bacteria is a commonly used antibacterial method.However,with the widespread use of traditional antibiotics,pathogens or pathogens have developed resistance to almost all available traditional antibiotics through de novo mutation or acquisition of resistance genes from other organisms.Therefore,developing novel efficient antibacterial agents that are not prone to drug resistance is extremely attractive.In this work,Cu@Cu₂O/C and D-NiPO-C_xnanocomposites with excellent antibacterial properties were successfully synthesized by a hydrothermal method followed by calcination.ZnO/C nanocomposites with strong adsorption and bactericidal properties were prepared by one-step calcination.And studied their antibacterial activity and the mechanism.The main research contents of this paper are as follows:(1)Carbon nanosheets decorated with core-shell Cu@Cu₂O nanoparticles(Cu@Cu₂O/C)were prepared by a facial hydrothermal method using copper D-gluconate.The as-prepared Cu@Cu₂O/C verified by varieties of characterizations were used as antibacterial samples to kill Gram-negative bacterium E.coli and Gram-positive bacterium S.aureus with an antibacterial efficiency up to 100%and 96.0%within 12 min in dark condition.These nanosheets could not only effectively anchor Cu@Cu₂O core-shell structured nanoparticles,but also bring more edge active sites,which could promote the generation of free-radicals.The preparation conditions of the catalyst with the best sterilization effect are discussed by changing the hydrothermal time.The excellent antibacterial activity is attributed to the synergy between the generation of·OH radicals and the sharp edges of the carbon nanosheets,which may be related to the destruction of bacterial cell integrity and the dysfunction of key components.(2)Glucose was used as the raw material,and carbon spheres with a diameter of about 150 nm were synthesized by a hydrothermal method.Nickel nitrate hexahydrate was used as nickel source,and D-NiPO-C_xcomposites with different carbon contents were synthesized by hydrothermal method and phosphating method.The as-prepared D-NiPO-C_0.4(with quality of carbon spheres of 400 mg)at a concentration of 100?g/mL exhibit antibacterial efficiencies of 98.3%and 71.9%for S.aureus and E.coli,respectively,under the light irradiation of 70 W halide lamp for 60 min.In the absence of light,the bactericidal rates against Escherichia coli and Staphylococcus aureus were only31.8%and 38.6%.The high performance of the D-NiPO-C_xsample is attributed to the synergistic effect of carbon radicals and other reactive species(~1O₂,·OH and·O₂^-),these active species are formed by the rapid separation and transfer of photobiomass.(3)Zinc gluconate was used as the raw material to synthesize ZnO/C nanocomposites by calcination.ZnO/C nanocomposites exhibited light-enhanced antibacterial effects against two common pathogenic bacteria Escherichia coli and Staphylococcus aureus.In addition,the difference of the sterilization effect of different calcination temperatures was also discussed,and its working mechanism was studied.