Toxic effects of titanium dioxide nanoparticles on microbial activity and metabolic flux

Abstract

The purpose of this research is to estimate and quantify the toxicity of titanium dioxide (TiO2) nanoparticles in microorganisms. Nano-sized particles of TiO2 were more toxic compared to micro-sized particles. Three microorganismal species, Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae, were used to test TiO2 antimicrobial effects. E. coli showed the lowest survival rate (36%), while S. cerevisiae showed the highest survival rate (71%). The antimicrobial effect of TiO2 was also dependent on ultraviolet ray wavelength. The survival ratio of E. coli was 40% at a 254 nm wavelength and 80% at 365 nm. To observe the effect of TiO2 on the intracellular metabolism, a metabolic flux analysis and the measurement of in vivo glucose-6-phosphate were performed. G6P concentration in cells exposed to TiO2 increased, and glycolysis flux was also higher than the controls.