Comparison of CuO and TiO2 Nanoparticles toxicity and Antibacterial Properties in the Solid Media

Toxicity assessment of material related to nanotechnology is necessary before excess development of this industry. On the other hand، specific characteristic of nanomaterials can be used in disinfection of other material. In this study toxicity and antibacterial properties of nano-TiO2 and nano-CuO were investigated with four bacterial species in solid media. Stock suspension of nanoparticles (10g-TSS/L) was diluted using Muller Hinton Agar to achieve 5-6000mg-TSS/L concentration. We prepared three Petri dishes for each concentration and refined bacteria were cultured on these Petri dishes. After culturing of these bacteria on the media containing nanoparticles، growth inhibition was determined. According to this data، 50% growth inhibition (EC50)، no observed effect concentration (NOEC) and 100% growth inhibition were determined. Our results showed that toxicity of TiO2 is more than CuO in solid media. In this regard، nano-TiO2 EC50 for Escherichia coli، Bacillus subtilis، Staphylococcus aureus، and Pseudomonas aeruginosa was calculated 181، 571، 93 and 933mg-TSS/L respectively. These figures for nano-TiO2 were 2550، 1609، 946، and 1231mg-TSS/L respectively. This study showed that compared with other bacteria studied، E. aureus due to high sensitivity and E. coli due to high resistance to both TiO2 and CuO nanoparticles are more proper as bioindicator in toxicity test and antibacterial test respectively.