Effect of lattice constant of zinc oxide on antibacterial characteristics

Zinc oxide powders were heated in different atmospheres at 800 and 1400 degreesC, of which the characterization and the antibacterial activity were studied by X-ray diffractometry and the measurement of the change in electrical conductivity with bacterial growth. The diffraction peaks corresponding to zinc oxide with hexagonal type structure were detected in all samples, which shifted in low-angle side with the increase in the oxidizability of atmosphere during heat-treatment. From the results of calculating lattice constants, a(o) and c(o), it was found that the value of c(o) in hexagonal structure increased with the increase in the oxidizability of atmosphere. On the samples heated at 1400degreesC, the changes of the c(o) value were less than those at 800degreesC. However, no change of the a(o) value showed, irrespective of atmosphere and temperature. Hydrogen peroxide that contributes to the occurrence of antibacterial activity was found to generate from all samples, and the generation amount increased with the increase of c(o) value; incidently the amount in the samples heated at 1400degreesC was less than that at 800degreesC. The antibacterial activity of zinc oxide increased with the increase of c(o) value; that is, it was found that the value of c(o) in crystal structure affected the antibacterial activity of zinc oxide. (C) 2004 Kluwer Academic Publishers.