The Antibacterial Effect of TiO2 Nanoparticles on Pathogenic Strain of Escherichia coli, In Vitro

Background and objectives: Human beings are often infected by microorganisms such as bacteria, yeasts, and viruses in the living environment. Research in antibacterial material containing various natural and inorganic substances has been intensive and attract the researchers attention. Nanotechnology has become one of the most practical technologies, because of unique physical and chemical properties of nanomaterials. Nanomaterials such as TiO 2 nanoparticles (TiO 2 -NPs), less than 100 nm in diameter, have become a new generation of advanced materials due to their brilliant and interesting optical, dielectric, and photo-catalytic characteristics from size quantization. Therefore, many efforts have been devoted to produce TiO 2 -NPs with controlled size, shape, and porosity for use in thin films, ceramics, composites, and catalysts. The antibacterial activities of some nanoparticles, makes them attractive as a new agents against pathogenic bacteria. Material and methods: Liquid and agar nutrient medium used for E.coli culture and antibacterial effect of 0.01, 0.5, 1 and 1.5% of nano-TiO2 evaluated via optical density (OD) and Kirby-Bauer disc diffusion test. Results: Optical density decrease was observed with nano-TiO2 concentration increase (0.218, 0.158, 0.075 and 0.031 respectively). Inhibition zone measurement showed the similar results. The maximum inhibition zone (5mm) was observed in 1.5% of nano-TiO2. Conclusion: Nanomaterials are known to inactivate cellular enzymes and DNA by binding to electron-donating groups such as carboxylates, amides, indoles, hydroxyls, thiols, and etc. They cause little pores in bacterial cell walls, leading to increased permeability and cell death.Based on this study, nano-TiO2 has efficient antibacterial effect and can be used as an antibacterial agent for different purposes.