eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-12-22 13 4 2003 2005 10.13005/bbra/2356 17018 article Roya Rashidi 1 Hamid Reza Ghorbani 1 Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran. Nanotechnology has become one of the most practical technologies, because of uniquephysical and chemical properties of nanomaterials.In this study, antibacterial effect of silver nanoparticles with average size 45nm on Escherichia coli strain wasinvestigated.Liquid and agar nutrient medium used for E.coli cultureand different antibiotics used for Disk diffusion technique to evaluate antibiotic resistance pattern of E.coli.Antibacterial effect of 1% and 3% of silver nanoparticles evaluated via discdiffusion test.Based on this study, nano-TiO2 has efficient antibacterial effect and can beused as an antibacterial agent for different purposes. https://www.biotech-asia.org/vol13no4/the-study-of-antibacterial-properties-nano-silver-colloid/ Silver nanoparticles; E. coli; Disc diffusion