title: Assessing the toxicity and the dissolution rate of zinc oxide nanoparticles using a dual-color Escherichia coli whole-cell bioreporter.
abstract: Particle toxicity and metal ions from the dissolution of metallic nanoparticles (NPs) can have environmentally toxic effects. Among the diverse metallic NPs, four types of zinc oxide NPs (ZnO-NPs)-two spherical (diameters <50 nm and <100 nm) and two wire (50 nm × 300 nm and 90 nm × 1000 nm) shaped-were examined using dual-color whole-cell bioreporters (WCBs) to elucidate the relationships among size, shape, and toxicity. The amount of Zn(II) ions dissolved from NPs was determined by measuring mCherry expression because the presence of Zn(II) ions induced the expression of mCherry from pZnt-mCherry in dual-color WCBs. The overall toxic effects were assessed by measuring Escherichia coli cell growth. The toxic effect on cell growth was determined by measuring the expression of eGFP from the dual-color WCBs to avoid interferences in the signal acquisition caused by inseparable NPs. The novel approach demonstrated here used dual-color WCBs to simultaneously assess the toxicity of ZnONPs on E. coli and the dissolution rates of ZnO-NPs. Toxicity varied depending upon the size and shape of the ZnONPs. The dissolution rate did not vary significantly according to size and shape; smaller sizes and wire shapes showed higher toxicity. Therefore, the physical properties of ZnONPs play a role in the overall toxic effect as well as dissolved Zn(II) ions.
authors: Department of Environmental Health Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, South Korea.
authors: Sunghoon
authors: S
authors: Kim
authors: Department of Environmental Health Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, South Korea.
authors: Yooeun
authors: Y
authors: Chae
authors: Department of Environmental Health Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, South Korea.
authors: Yerin
authors: Y
authors: Kang
authors: Department of Environmental Health Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, South Korea.
authors: Youn-Joo
authors: YJ
authors: An
authors: Department of Environmental Health Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, South Korea. Electronic address: yyoon21@gmail.com.
authors: Youngdae
authors: Y
authors: Yoon
mesh_terms: D003116:Color; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D012995:Solubility; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D015034:Zinc Oxide; D000097573:Red Fluorescent Protein; C485184:enhanced green fluorescent protein
keywords: Dissolution rate; Fluorescence protein; Toxicity; Whole-cell bioreporter; Zinc oxide nanoparticles