title: Antibacterial properties and mechanism of graphene oxide-silver nanocomposites as bactericidal agents for water disinfection.
abstract: Providing clean and affordable drinking water without harmful disinfection byproducts generated by conventional chemical disinfectants gives rise to the need for technological innovation. Nanotechnology has great potential in purifying water and wastewater treatment. A graphene oxide-silver (GO-Ag) nanocomposite with excellent antibacterial activity was prepared and characterized by transmission electron microscope and X-ray photoelectron spectroscopy. The tests were carried out using Escherichia coli and Staphylococcus aureus as model strains of Gram-negative and Gram-positive bacteria, respectively. The effect of bactericide dosage and pH on antibacterial activity of GO-Ag was examined. Morphological observation of bacterial cells by scanning electron microscope showed that GO-Ag was much more destructive to cell membrane of Escherichia coli than that of Staphylococcus aureus. Experiments were carried out using catalase, superoxide dismutase and sodium thioglycollate to investigate the formation of reactive oxygen species and free silver ions in the bactericidal process. The activity of intracellular antioxidant enzymes was measured to investigate the potential role of oxidative stress. According to the consequence, synergetic mechanism including destruction of cell membranes and oxidative stress accounted for the antibacterial activity of GO-Ag nanocomposites. All the results suggested that GO-Ag nanocomposites displayed a good potential for application in water disinfection.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Biao
authors.initials: B
authors.lastname: Song
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Chang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: zgming@hnu.edu.cn.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: jilaigong@gmail.com.
authors.forename: Jilai
authors.initials: J
authors.lastname: Gong
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Yingna
authors.initials: Y
authors.lastname: Chang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002374:Catalase / Q000378:metabolism; D004203:Disinfection; D004926:Escherichia coli / Q000201:enzymology; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D015227:Lipid Peroxidation; D053768:Metal Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry; D018384:Oxidative Stress; D010087:Oxides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D012834:Silver / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000201:enzymology; D013482:Superoxide Dismutase / Q000378:metabolism; D013864:Thioglycolates / Q000378:metabolism; D062065:Wastewater; D014867:Water / Q000737:chemistry; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D002374:Catalase; D006108:Graphite; D007477:Ions; D010087:Oxides; D012834:Silver; D013482:Superoxide Dismutase; D013864:Thioglycolates; D062065:Wastewater; D014867:Water; C017487:2-mercaptoacetate
keywords: Antibacterial; Graphene oxide; Silver nanoparticles; Water disinfection