Antibacterial Activities of Nanoparticles of Titanium dioxide, Intrinsic and Doped With Indium and Iron

Abstract

The need for new antimicrobial compounds has been attention on developing new and emerging materials based on nanoparticles with antimicrobial activity. The aim of this research was to evaluate the antibacterial activities of nanoparticles of titanium dioxide, intrinsic and doped with Indium and Iron in Escherichia coli and Staphylococcus aureus. The bacteriostatic effect of TiO 2 nanoparticles (two samples), TiO 2 :Fe and TiO 2 :In with concentrations of 50, 250 500 µg/ml. It was observed by optical density measurements. The bactericidal effect was determined by plate count agar Muller-Hinton, where they were incubated for 12 hours: 50 µl of bacterial suspension (concentration 1.5 x 10 6 bacteria/ml), concentration 50 µl of nanoparticles suspended at concentrations between 39 and 2500 µg/ ml. Then, to 10 -6 dilutions were made and plated on agar for colony counts. There were significant decreases P < 0.05 in the bacterial optical densities with respect to control, using TiO 2 nanoparticles prepared with different contents of acetic acid at concentrations of 250 and 500 µg/ml versus E. coli and S. aureus. In the plate counts, there was a significant reduction, P < 0.05 in the number of CFU of E. coli using TiO 2 nanoparticles (50% AcAc) in concentrations 39 to 2500 µg/ml; in the case of S. aureus decrease seen in concentrations 78 to 2500 µg/ml. In both bacteria, we observed decreased bacterial growth with TiO 2 nanoparticles at concentrations of 156 -2500 µg/ml. The two variants of preparing TiO 2 nanoparticles have higher intrinsic activity against E. coli and S. aureus, while nanoparticles doped with Indium and Iron, not power the antibacterial effect.

Impact of nanoparticles on transcriptional regulation of catabolic genes of petroleum hydrocarbon‐degrading bacteria in contaminated soil microcosms

“… in TiO 2 ‐NPs treated soils may indicate that natural attenuation and biodegradation of petroleum hydrocarbons in contaminated soil may not be much affected. Although TiO 2 ‐NPs are known to have antimicrobial activity , this reduced toxicity of TiO 2 ‐NPs toward endogenous soil microorganism could be attributed to the fact that TiO 2 ‐NPs in its rutile form is more stable than the anatase form and can interact with other components in the soil especially heavy metals rendering its availability . Some reports indicated that TiO 2 ‐NPs were toxic to some bacterial strains such as E. coli , P. fluorescens , S. typhimurium , B. subtilis , B. licheniformis , and N. europaea .…”