Abstract
Antimicrobial activity of the mixed powders of MgO and ZnO and even the solid solution powders of these ceramics was studied by measuring the change in electrical conductivity with bacterial growth of Staphylococcus aureus (Conductance method).
MgO and ZnO powders were heated at 1400°C for 3 h in air and then they were mixed with various mass ratios (MgO/ZnO). After milling the mixed powders by planetary ball mill, the powders with a average particle size of 0.1 μm were used in antimicrobial tests. It was clarified that the antimicrobial activity of the mixed powders in the mass ratio (MgO/ZnO) more than 1 was comparable with that of MgO. In the case of the mixed powders with the ratio less than 1, however, the activity decreased, compared with MgO.
MgO-ZnO solid solution powders were synthesized by heating at 1400°C for 3 h in air. A single phase with cubic type structure was obtained in the mass ratio (MgO/ZnO) of 4.0 and 1.5, but the ratio of 0.67 resulted in a ZnO phase in addition to MgO-ZnO solid solution. From the results of antimicrobial tests by using the solid solution powders with a particle size of 0.1 μm, it was found that the antimicrobial activity against Staphylococcus aureus decreased with increasing the dopant amount of ZnO in MgO-ZnO solid solution.
