The Antimicrobial Effect and ROS Redox Activity of Nb₂O₅-Containing Powders Obtained by the Sol-Gel Method

The aim of the present paper is to study the antimicrobial effects of Nb₂O₅-containing nanosized powders. A combination of inorganic [telluric acid (H₆TeO₆)] and organic [Ti(IV) n-butoxide, Nb(V) ethoxide (C₁₀H₂₅NbO₅)] precursors was used to prepare gels. To allow for further hydrolysis, the gels were aged in air for a few days. The gels were amorphous, but at 600 °C the amorphous phase was absent, and only TiO₂ (anatase) crystals were detected. The average crystallite size of TiO₂ (anatase) was about 10 nm. The UV-Vis spectrum of the as-prepared gel showed red shifting in the cut-off region. The obtained nanopowders were evaluated for antimicrobial properties against E. coli ATCC 25922, P. aeruginosa ATCC 27853, S. aureus ATCC 25923, and C. albicans 18804. Among these, only E. coli was examined in combination with the antibiotic ciprofloxacin to assess whether there was a potential synergistic effect. The results showed that the material exhibited antibacterial activity against the abovementioned bacterial strains but not against C. albicans. In the case of E. coli combined with ciprofloxacin, a concentration-dependent enhancement in antibacterial activity was observed. The obtained samples can be considered as prospective materials for use as environmental catalysts. The newly synthesized nanocomposite showed a balancing, modulating, and neutralizing effect on the generation of ROS. The inhibitory effect was preserved in all tested model chemical systems at pH 7.4 (physiological), indicating potential biological applications in inflammatory and oxidation processes in vivo.