Shape-dependent bactericidal activity of TiO2 for the killing of Gram-negative bacteria Agrobacterium tumefaciens under UV torch irradiation

• Published in: Environmental science and pollution research international Vol. 20; no. 9; pp. 6521 - 6530
• Main Authors: Aminedi, Raghavendra, Wadhwa, Gunveen, Das, Niranjan, Pal, Bonamali
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2013; Springer Nature B.V
• Subjects: Agrobacterium tumefaciens; Agrobacterium tumefaciens - cytology; Agrobacterium tumefaciens - drug effects; Agrobacterium tumefaciens - radiation effects; Anti-Bacterial Agents - pharmacology; Antimicrobial activity; Antimicrobial agents; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atoms & subatomic particles; Bacteria; Bactericidal activity; Biodegradation; Carbohydrates; Cell culture; Cell membranes; Cell morphology; Cell surface; Cell viability; Chemicals; Crystal structure; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental studies; Fourier transforms; Gram-negative bacteria; Irradiation; Membrane permeability; Microscopy, Electron, Transmission; Morphology; Nanoparticles; Nanotechnology; Nanotubes; Nucleic acids; Phospholipids; Photocatalysis; Photochemical Processes; Pollutants; Research Article; Slurries; Spectral analysis; Studies; Surface area; Thin films; Titanium - pharmacology; Titanium dioxide; Transmission electron microscopy; Ultraviolet radiation; Ultraviolet Rays; Waste Water Technology; Water Management; Water Pollution Control; Patiala India; India; Nanoscale TiO; bacteria; photocatalytic activity; particle; Biocidal activity of TiO; TiO; nanorod and nanotube
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-013-1717-7

This paper demonstrated the relative bactericidal activity of photoirradiated (6W-UV Torch, λ  > 340 nm and intensity = 0.64 mW/cm 2 ) P25–TiO 2 nanoparticles, nanorods, and nanotubes for the killing of Gram-negative bacterium Agrobacterium tumefaciens LBA4404 for the first time. TiO 2 nanorod (anatase) with length of 70–100 nm and diameter of 10–12 nm, and TiO 2 nanotube with length of 90–110 nm and diameter of 9–11 nm were prepared from P-25 Degussa TiO 2 (size, 30–50 nm) by hydrothermal method and compared their biocidal activity both in aqueous slurry and thin films. The mode of bacterial cell decomposition was analyzed through transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR), and K + ion leakage. The antimicrobial activity of photoirradiated TiO 2 of different shapes was found to be in the order P25–TiO 2  > nanorod > nanotube which is reverse to their specific surface area as 54 < 79 < 176 m 2  g −1 , evidencing that the highest activity of P25–TiO 2 nanoparticles is not due to surface area as their crystal structure and surface morphology are entirely different. TiO 2 thin films always exhibited less photoactivity as compared to its aqueous suspension under similar conditions of cell viability test. The changes in the bacterial surface morphology by UV-irradiated P25–TiO 2 nanoparticles was examined by TEM, oxidative degradation of cell components such as proteins, carbohydrates, phospholipids, nucleic acids by FT-IR spectral analysis, and K + ion leakage (2.5 ppm as compared to 0.4 ppm for control culture) as a measure of loss in cell membrane permeability.