Comparative Study of Antimicrobial Activities of Tio2 and Cdonanoparticles Against the Pathogenic Strain of Escherichia Coli

Background: and objectives: the aim of this study was to detect the antibacterial properties of0.01, 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 theantibacterial 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% ofboth nanoparticles showed considerably decreased bacterial number. a 4.5 and 1.9 times decreasein the od value was found in the presence of 1 and 0.5% nano-tio2, respectively (p< 0.001). 1.5and 3.3 times decreased od was seen in the presence of 0.5 and 1% nano-cdo, respectively, ascompared to control (p<0.001). in the second study, 6.3 log cfu/ml of e. coli were present in thecultures treated with 1% nano-tio2 and cdo at 4 ºc in water. control e. coli cells survived for 12days while complete cell death was seen when 1% nano-tio2 was applied for 13 hours as comparedto 1% nano-cdo, which showed complete cell death after 15 hours. in the third study, e. coli wasgrown in the agar medium with and without both nanoparticles and suppressed growth (4.5 and 5.6times; p<0.001) was seen in the presence of 1% nano-cdo and -tio2, respectively.conclusion: in spite of the fact that both nanoparticles showed bactericidal activity, nano-tio2has proven to be more efficient antibacterial agent as compared to nano-cdo.