title: Mechanism of enhanced antibacterial activity of ultra-fine ZnO in phosphate buffer solution with various organic acids.
abstract: Ultra-fine-ZnO showed low toxicity in complex water matrix containing multiple components such as PBS buffer and the toxic mechanism of ultra-fine-ZnO has not been clearly elucidated. In present study, enhanced antibacterial activity of 200 nm diameter ultra-fine-ZnO in PBS buffer against Bacillus cereus and Escherichia coli were observed in the presence of several organic acids in comparison with ultra-fine-ZnO in PBS buffer alone. These findings indicated that the toxic effects of the ultra-fine-ZnO was dependent on the concentration of released Zn2+which was affected by organic acids. The production of reactive oxygen species (ROS) did not responsible to the toxic mechanism of ultra-fine-ZnO which was tested using the antioxidant N-Acetylcysteine (NAC). Indeed, ultra-fine-ZnO induced bacteria cell membrane leakages and cell morphology damages that eventually led to cell death, which were confirmed using propidium monoazide (PMA) in combination with PCR and scanning electron microscopy (SEM). All data gathered herein suggested that released Zn2+played a major role in the microbial toxicity of ultra-fine-ZnO.
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China; Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang 330047, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Kuang
authors.affiliation: Center of Analysis and Testing of Nanchang University, Nanchang 330047, China.
authors.forename: Yingxia
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China. Electronic address: kidyxu@163.com.
authors.forename: Hengyi
authors.initials: H
authors.lastname: Xu
authors.affiliation: Zystein, LLC, Fayetteville, AR 72704, USA.
authors.forename: Zoraida P
authors.initials: ZP
authors.lastname: Aguilar
authors.affiliation: Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang 330047, China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang 330047, China. Electronic address: weihua114@live.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Wei
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001386:Azides / Q000737:chemistry; D001409:Bacillus cereus / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D002021:Buffers; D002264:Carboxylic Acids / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D050296:Microbial Viability / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry*; D011419:Propidium / Q000031:analogs & derivatives / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D012995:Solubility; D012996:Solutions; D015034:Zinc Oxide / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001386:Azides; D002021:Buffers; D002264:Carboxylic Acids; D010710:Phosphates; D017382:Reactive Oxygen Species; D012996:Solutions; C533957:propidium monoazide; D011419:Propidium; D015034:Zinc Oxide
keywords: Antibacterial activity; Bacillus cereus; Escherichia coli; Released Zn(2+); Ultra-fine-ZnO