title: Antibacterial activity of ZnO powder with crystallographic orientation.
abstract: ZnO powder with crystallographic orientation was prepared from the mixed aqueous solution of zinc chloride, tri-ethanol amine and thio-urea. From X-ray diffraction measurement, as-prepared powder was found to have the orientation along a-b axes of hexagonal structure, and a needle-like shape with the aspect ratio of 5 was observed by scanning electron microscope, indicating that as-prepared powder had crystallographic orientation. In the tests of antibacterial activity by colony count method, ZnO powders with and without crystallographic orientation were used in present work. Survival ratio of bacteria decreased with increasing powder concentration, i.e., increase in antibacterial activity. The antibacterial activity in ZnO powder with crystallographic orientation was weaker than that in commercial ZnO powder without orientation at same powder concentration. Regarding specific surface area of the powders used in antibacterial tests, however, antibacterial activity in powder with orientation was found to be similar to that without orientation; that is, the crystallographic orientation of ZnO did not affect antibacterial activity. The activity toward Staphylococcus aureus was stronger than that toward Escherichia coli, irrespective of the kind of powders.
authors.affiliation: Center for Geo-Environmental Science, Faculty of Engineering and Resource Science, Akita University, 1-1 Tegata Gakuen-machi, Akita 010-8502, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ohira
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Iida
authors.forename: Zenbe-E
authors.initials: ZE
authors.lastname: Nakagawa
mesh_terms: D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008968:Molecular Conformation; D010316:Particle Size; D011208:Powders / Q000737:chemistry; D013211:Staphylococcus aureus; D015034:Zinc Oxide / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D011208:Powders; D015034:Zinc Oxide