Antibacterial activity of nanoparticles of titanium dioxide, intrinsic and doped with indium and iron

Abstract

The need for new antimicrobial compounds has drawn attention on developing new and emerging materials based on nanoparticles with antimicrobial activity. The aim of this research was to evaluate the antibacterial activity of nanoparticles of titanium dioxide, intrinsic and doped with Indium and Iron in Escherichia coli and Staphylococcus aureus. The bacteriostatic effect of Ti0₂ nanoparticles (two samples), Ti0₂:Fe and Ti0₂:In with concentrations of 50, 250 and 500 µg/ml, was observed by optical density measurements. The bactericidal effect was determined by plate count agar Muller-Hinton, where they incubated for 12 h: 50 µl of bacterial suspension (concentration 1.5 × 10⁶ bacterium/ml), con 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 in the bacterial optical densities with respect to control, using TiO₂ 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 in the number of CFU of E. coli using TiO₂ 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 TiO₂ nanoparticles at concentrations of 156 to 2500 µg/ml. The two variants of preparing TiO₂ nanoparticles have higher intrinsic activity against E. coli and S. aureus, while nanoparticles doped with Indium and Iron, could not overpower the antibacterial effect.

Keywords: Titanium oxide, nanoparticles, antibacterial activity.