Antibacterial activity of Nb–aluminum oxide prepared by the non-hydrolytic sol–gel route

Brazil has been the largest producer of niobium (Nb2O5) since 1980, and this material is usually applied to reduce corrosion in alloys. In addition, it has recently been evaluated for use in other technological areas, such as adsorption and catalysis. This paper presents the results of the antibacterial activity of Nb–aluminum oxide, designated MAC–Nb5+, prepared by the non-hydrolytic sol–gel route. The resulting material MAC–Nb5+ was characterized by several techniques including X-ray diffraction, thermal analysis, infrared absorption spectroscopy, differential pulse voltammetry, surface area measurements, and scanning electron microscopy. The displacements of the bands due to Al–O and Al–OH in the infrared spectra of MAC–Nb5+ in relation to alumina confirmed the coordination of Nb5+ ions to the surface and inside the pores of the alumina matrix. The powder XRD of MAC–Nb5+ suggested that the material is amorphous and that the niobium oxide is well-dispersed over the alumina matrix. Differential pulse voltammetry revealed the redox process that involves Nb–O–Al. Results from the biological assays for determination of the antibacterial activity of MAC–Nb5+ were obtained by the following methodologies: determination of the minimum inhibitory concentration and antibacterial activity assay by agar diffusion. It was observed that MAC–Nb5+ displays antibacterial activity against all the tested bacteria.

SEM micrograph of MAC–Nb5+ prepared by the non-hydrolytic sol–gel route and evaluation of the antimicrobial activity against microorganisms present in the oral cavity.Figure optionsDownload high-quality image (197 K)Download as PowerPoint slideResearch highlights
► XRD, TGA and FTIR analysis confirm the formation of Nb-aluminium oxide.
► The redox process of Nb–O–Al explain the biological activity.
► MAC–Nb5+ is most efficient against the microorganism Streptococcus salivarius.