Antibacterial Effect of Green Synthesized TiO2 Nanoparticles

Nanotechnology is gaining momentum due to its diverse application in various fields of science. In this paper, the antibacterial properties of green synthesized TiO2 nanoparticles were studied for both Gram-positive and Gramnegative bacteria. The nanoparticles were synthesized using extracellular secretions of Lactobacillus sp. These studies demonstrate that the biologically synthesized TiO2 nanoparticles have a wide range of antibacterial activities toward microorganisms. The MIC value for the TiO2 nanoparticles was found to be 62.5 pg/ml for both S. aureus and E. co/i. The Inhibition was further confirmed using Disc diffusion assay. It is evident from the zone of inhibition that TiO2 nanoparticles possess potent bactericidal activity. Further, growth curve study of S. aureus and E. coli in the presence and absence of TiO2 nanoparticles has been done. Proton pumping ATPase activity of S. aureus and E. coil were examined and found to be enhanced significantly with treated nanoparticles as compared to the control. Glucose used as positive control and found to enhance the proton efflux activity with respect to control. Transmission electron microscopy analysis of bacterial strain treated with TiO2 nanoparticles, shows alterations in morphology of cell wall, damage and lysis of plasma membrane. Also the nanoparticles show less haemolytic activity compared to the antibiotic ampicillin. This study indicates that the green synthesized nanoparticles can be used as effective antibacterial agents.