Synergistic antibacterial activity of barium doped TiO2 nanoclusters synthesized by microwave processing

Abstract

In this work, we investigated the antibacterial activity of TiO₂ and Ba doped TiO₂ nanoparticles synthesised by a microwave assisted method. The obtained nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, ultra-violet visible spectroscopy, energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy. XRD patterns revealed preferentially oriented (101) TiO₂ anatase phase, which changed to anatase–rutile mixed phase after Ba²⁺ doping. The vibrational spectra show significant shifts in the peaks with Ba addition, indicating the successful incorporation of Ba²⁺ ions into TiO₂. The optical spectra revealed increase in band gap with Ba doping, thereby allowing the delay in recombination rate, favouring antibacterial activity. The surface morphology of TiO₂ show spherical shaped grains with increased porosity after Ba doping. EDS analysis confirmed the phase-purity of the synthesized powders. The potential toxicity of nanosized TiO₂ and Ba doped TiO₂ were investigated using both Gram positive and Gram negative bacteria as test organisms. The antibacterial activity was found to be higher for Ba doped TiO₂ nanoparticles compared to pure TiO₂ nanoparticles, due to reduced particle size and high specific surface area leading to enhanced particle surface reactivity to light and H₂O adsorption.