[Investigating the effect of silver nanoparticles on e.coli growth]

ABSTRACT

Nanoparticles are very small pieces of material that have different applications in medical fields. Nanosilver technology is a functional branch in nanotechnology. Different studies have proved antimicrobial effects and useful functions of nanosilver in biotechnology field and its specific inhibitory effects on microbes. As no exact report about antibacterial effects of these nanoparticles has been made, this study was conducted to investigate silver inhibitory effects on E.coli. Nanosilver particles at concentration of 100, 200, 300, 400 and 500ppm were inseminated on blank anti biogram discs and were placed on cultivated nutrient agar environment by 0.5 Mac Farland`s standard. Then, inhibition zone diameter was measured in the first, second, and sixth day. T-test was used to compare the average inhibition zone in control and treatment groups and the value p<0.05 was considered as statistically significant. In the first day after the treatment of nanosilver particles at a concentration of 400ppm, the average inhibition zone diameter was 2.30 +/- 0.43mm in E.coli that has been increased significantly in comparison with control culture [p=0.01]. In the second day after treatment at a concentration of 400ppm, the average disc diameter was 2.48 +/- 0.39mm which shows that these values have been increased significantly in comparison with control groups [p=0.01], but they were not significantly different from the first day. Since Nonotechnology has various applications in different fields, expanding these results could be helpful in biomedical therapeutic of bacteria diseases. In conclusion, our results may provide this important insight that nanoparticles could replace many antibiotics without many side effects