MohammadReza Elahifard - Chemical Engineering Department, Faculty of Engineering, Ardakan University

The Co-doped TiO۲ nanoparticles were investigated for their antibacterial activities on Staphylococcus aureus (S. aureus) bacteria. Their morphological features and characteristics such as particle size, surface area, and visible light absorbing capacity were compared and discussed. Scanning electron microscopy, X-ray diffraction, and UV-visible spectrophotometry were used to characterize it. UV–vis diffuse reflectance absorption measurement of doped titania nanoparticles shows the optical absorption in the visible region; which also confirms the incorporation of cobalt ions in TiO۲ crystal lattice. The inactivation of S. aureus (as an example of Gram-positive bacteria) with Co-doped TiO۲ was investigated in the absence and presence of visible light. The survival number of all bacteria species is not affected in dark with nanoparticles and in light condition without nanoparticles. Antibacterial activity tests were conducted using undoped, and Co-doped TiO۲. The Co-doped TiO۲ nanoparticles show higher antibacterial activity than pure TiO۲. The band gap narrowing of Codoped TiO۲ can induce more visible light absorption and leads to the superb antibacterial properties of this material. The complete inactivation time for S. aureus at an initial cell concentration of ۲.۷ × ۱۰(۴) CFU/mL was ۴۲۰ min.

Co-doped TiO۲, Staphylococcus aureus, nanoparticles