Antimicrobial effect of TiO2 doped with Ag and Cu on Escherichia coli and Pseudomonas putida

[摘要] Antimicrobial effect of TiO2doped with Ag and Cu on Gram-negative bacteria Escherichia coli and Pseudomonas putida is studied. The thin films are deposited on glass substrates without heating during the deposition by r.f. magnetron co-sputtering of TiO2target and pieces of Ag and Cu. The studied films, thickness about 65 nm, were as deposited and annealed (5200C, 4h, N2+5%H2, 4Pa). The as deposited thin films TiO2:Ag:Cu have band gap energy of 3.56 eV little higher than the band gap of crystalline anatase TiO2which can be explained with the quantum effect of the granular structure of r.f. magnetron sputtered films. The annealed samples have band gap of 2.52 eV due to formation of donor levels from Ag and Cu atoms near the bottom of the conduction band. The toxic effect was determined through the classical Koch's method and the optical density measurements at λ=610 nm. The as deposited TiO2:Ag:Cu thin films demonstrate stronger inhibition effect - bactericidal for P. putida and bacteriostatic for E. coli (up to the 6thhour) in comparison with the annealed samples. The both methods of study show the same trends of the bacterial growth independently of their different sensitivity which confirms the observed effect.

[发布机构] Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, Sofia; 1784, Bulgaria^1;Department of General and Industrial Microbiology, Faculty of Biology, Sofia University, St. Kl. Ohridski, 8 D. Tzankov, Sofia; 1164, Bulgaria^2

[效力级别] 材料科学 [学科分类] 材料科学（综合）

[关键词] Anti-microbial effects;As-deposited thin films;Gram-negative bacteria;Granular structuress;Inhibition effect;Magnetron co-sputtering;Magnetron sputtered films;Pseudomonas putida