comparative study of antimicrobial activities of tio2 and cdo nanoparticles against the pathogenic strain of escherichia coli

background: and objectives:the aim of this study was to detect the antibacterial properties of 0.01, 0.5 and 1% nano-tio2 and -cdo against e. coli. materials and methods: e. coli was cultured in liquid and agar nutrient medium to evaluate the antibacterial effects of 0.01, 0.05 and 1% of both nano-tio2 and -cdo via the optical density (od) and log cfu/ml measurements. results: non-significant effect was seen for 0.01% of both nano-specimens. while, 0.05 and 1% of both nanoparticles showed considerably decreased bacterial number. a 4.5 and 1.9 times decrease in the od value was found in the presence of 1 and 0.5% nano-tio2, respectively(p< 0.001). 1.5 and 3.3 times decreased od was seen in the presence of 0.5 and 1% nano-cdo, respectively, as compared to control (p