title: Antimicrobial mechanism based on H2O2 generation at oxygen vacancies in ZnO crystals.
abstract: The production of H2O2 has been taken for a crucial reason for antimicrobial activity of ZnO without light irradiation. However, how the H2O2 generates in ZnO suspension is not clear. In the present work, the comparatively detections on three kinds of ZnO, tetrapod-like ZnO whiskers (t-ZnO), nanosized ZnO particles (n-ZnO), and microsized ZnO particles (m-ZnO), showed that the antimicrobial activity of ZnO was correlated with its production of H2O2. Oxygen vacancy (V(O)) in the surface layer of ZnO crystals determined by XPS indicated that it was quite probably involved in the production of H2O2. To validate the role of V(O), the concentration of VO in t-ZnO was adjusted by heat-treatment under the atmospheres of H2, vacuum, and O2, respectively, and the H2O2 production and antimicrobial effect were detected. Consistently, the t-ZnO treated in H2, which possessed the most V(O) in its crystal, produced the most H2O2 and displayed the best antimicrobial activity. These results provide the basis for developing a more detailed mechanism for H2O2 generation catalyzed by ZnO and for taking greater advantage of this type of antimicrobial agent.
authors.affiliation: Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Xu
authors.forename: Dan
authors.initials: D
authors.lastname: Chen
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yi
authors.forename: Man
authors.initials: M
authors.lastname: Jiang
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Zuowan
authors.initials: Z
authors.lastname: Zhou
authors.forename: Ximei
authors.initials: X
authors.lastname: Fan
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: David
authors.initials: D
authors.lastname: Hui
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D003460:Crystallization; D004926:Escherichia coli / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000138:chemical synthesis* / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D010100:Oxygen / Q000737:chemistry*; D010316:Particle Size; D013329:Structure-Activity Relationship; D013499:Surface Properties; D015034:Zinc Oxide / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D006861:Hydrogen Peroxide; D010100:Oxygen; D015034:Zinc Oxide