title: Whole-cell Escherichia coli-based bio-sensor assay for dual zinc oxide nanoparticle toxicity mechanisms.
abstract: A whole-cell biosensor assay for dual ZnO nanoparticle toxicity mechanisms has been developed based on the transcriptional response of Escherichia coli to: (1) Zn(2+) from ZnO nanoparticle dissolution with genes zntA (Zn(2+) efflux) and znuABC (Zn(2+) uptake); and (2) redox stress from ZnO nanoparticle photo-electron production under ultraviolet light with genes soxS and katG. Both processes occur in a dispersion of ZnO nanoparticles leading to toxicity. ZnO nanoparticle dissolution was measured independently by ICP-MS and photo-radical generation was confirmed by the stochiometric reduction of the redox dye, 2, 6-dichloroindolphenol (DCPIP). The whole-cell biosensor can detect both toxicity mechanisms and is a species-specific assay capable of discriminating between ZnO nanoparticles and the Zn(2+) dissolution product.
authors: Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.
authors: Jonathan S
authors: JS
authors: Mcquillan
authors: Andrew M
authors: AM
authors: Shaw
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D053758:Nanoparticles / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods; D015034:Zinc Oxide / Q000633:toxicity*
chemical_list: D015034:Zinc Oxide
keywords: Escherichia coli; Real time PCR; Stress response; Whole cell biosensor; Zinc oxide nanoparticle