Synthesis, characterization and comparative study of nano-Ag-TiO2 against Gram-positive and Gram-negative bacteria under fluorescent light

Currently, some of the major problems affecting the world are air pollution as well as microbial contamination. Every time we breathe, we are risking our lives by inhaling dangerous chemicals and biological contaminants that have found their way into the air. Therefore this work focuses on the antibacterial activity of Ag-TiO2 to overcome the microbial contaminant and infectious disease. Ag-TiO2 nanosolution were synthesized by sal gel method and found to be an effective visible light driven photocatalyst. The nanosolutions were characterized by X-ray diffraction (XRD), transmittance electron microscopy (TEM), photoluminescence (PL) spectra, and X-ray photoelectron spectroscopy (XPS). At the concentration of 0.2-0.1 M, Ag-TiO2 caused 100% inhibition of bacterial growth. The antibacterial efficacy of Ag-TiO2 was evaluated with two kinds of bacteria; Gram-positive and Gram-negative. The colony count of Ag-TiO2 against Gram-negative were evaluated with stain such as Escherichia coli, Pseudomonas aeruginosa and Shigella while for Gram-positive were investigated with Staphylococcus aureus, Bacillus subtilis, Bacillus cereus. Colony count results indicated that Ag-TiO2 able to kill bacteria at the lowest concentration of 0.05 M that contains 0.06 mol % Ag. From the SEM and TEM observation, the survival of the Gram-positive was low and the decomposition was rapid as compared to Gram-negative bacteria. (C) 2014 Elsevier Ltd. All rights reserved.