Antimicrobial effect of Al2O3, Ag and Al2O3/Ag thin films on Escherichia coli and Pseudomonas putida

[摘要] The influence of Al2O3, Ag and Al2O3/Ag thin films on bacterial growth of Gramnegative bacteria Pseudomonas putida and Escherichia coli is studied. The nanostructured thin films are deposited on glass substrates without intentional heating through r.f. magnetron sputtering in Ar atmosphere of Al2O3and Ag targets or through sequential sputtering of Al2O3and Ag targets, respectively. The individual Ag thin films (thickness 8 nm) have a weak bacteriostatic effect on Escherichia coli expressed as an extended adaptive phase of the bacteria up to 5 hours from the beginning of the experiment, but the final effect is only 10 times lower bacterial density than in the control. The individual Al2O3film (20 nm) has no antibacterial effect against two strains E. coli - industrial and pathogenic. The Al2O3/Ag bilayer films (Al2O320 nm/Ag 8 nm) have strong bactericidal effect on Pseudomonas putida and demonstrate an effective time of disinfection for 2 hours. The individual films Al2O3 and Ag have not pronounced antibacterial effect on Pseudomonas putida. A synergistic effect of Al2O3/Ag bilayer films in formation of oxidative species on the surface in contact with the bacterial suspension could be a reason for their antimicrobial effect on E. coli and P. putida.

[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;Department of Biotechnology and Food Technology, University of Russe A. Kanchev, 42 Aprilsko vastanie blvd., Razgrad, Russia^3

[效力级别] 材料科学 [学科分类] 材料科学（综合）

[关键词] Anti-microbial effects;Antibacterial effects;Bacterial suspensions;Bactericidal effects;Gram-negative bacteria;Nanostructured thin film;R.F. magnetron sputtering;Sequential sputtering