Effective factor on antibacterial characteristics of Mg1−XNiXO solid solution

Mg1−XNiXO solid solution powder samples with different chemical compositions were prepared by heating MgO–NiO mixtures at 1300 °C for 12 h in air. From XRD measurement, all powder samples were indexed as a single phase of cubic structure, of which the diffraction peaks shifted to high-angle side with the increase of doping amount of NiO. The pH values of the solution dispersed with the powder samples decreased when the doping amount of NiO in solid solution was increased. Antibacterial activity of the powder samples was examined by colony count method. In the result, the antibacterial activity of Mg1−XNiXO was remarkably weaker than original MgO powders, irrespective of the kind of bacteria. In addition, it was found that the antibacterial activity of Mg1−XNiXO reduced with increasing the doping amount of NiO. Two factors, the generated amount of O2− and the eluted amount of Ni2+ ions affected the antibacterial activity of Mg1−XNiXO solid solution. Especially, the stability of O2− in aqueous solution is dependent on pH value. Therefore, the strength of antibacterial activity was associated with the pH values in the dispersed solution of Mg1−XNiXO.

► We prepared Mg1−XNiXO solid solutions with different chemical compositions.
► We tested the antibacterial activity for Escherichia coli and Staphylococcus aureus.
► The antibacterial activity decreased with increasing the doping amount of NiO.
► The antibacterial activity of Mg1−XNiXO solid solution was dependent on the pH values.