Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/80010
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Type: | Journal article |
Title: | A whole-cell biosensor for the detection of gold |
Author: | Zammit, C. Quaranta, D. Gibson, S. Zaitouna, A. Ta, C. Brugger, J. Lai, R. Grass, G. Reith, F. |
Citation: | PLoS One, 2013; 8(8):1-8 |
Publisher: | Public Library of Science |
Issue Date: | 2013 |
ISSN: | 1932-6203 1932-6203 |
Editor: | Bansal, V. |
Statement of Responsibility: | Carla M. Zammit, Davide Quaranta, Shane Gibson, Anita J. Zaitouna, Christine Ta, Joël Brugger, Rebecca Y. Lai, Gregor Grass, Frank Reith |
Abstract: | Geochemical exploration for gold (Au) is becoming increasingly important to the mining industry. Current processes for Au analyses require sampling materials to be taken from often remote localities. Samples are then transported to a laboratory equipped with suitable analytical facilities, such as Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) or Instrumental Neutron Activation Analysis (INAA). Determining the concentration of Au in samples may take several weeks, leading to long delays in exploration campaigns. Hence, a method for the on-site analysis of Au, such as a biosensor, will greatly benefit the exploration industry. The golTSB genes from Salmonella enterica serovar typhimurium are selectively induced by Au(I/III)-complexes. In the present study, the golTSB operon with a reporter gene, lacZ, was introduced into Escherichia coli. The induction of golTSB::lacZ with Au(I/III)-complexes was tested using a colorimetric β-galactosidase and an electrochemical assay. Measurements of the β-galactosidase activity for concentrations of both Au(I)- and Au(III)-complexes ranging from 0.1 to 5 µM (equivalent to 20 to 1000 ng g⁻¹ or parts-per-billion (ppb)) were accurately quantified. When testing the ability of the biosensor to detect Au(I/III)-complexes(aq) in the presence of other metal ions (Ag(I), Cu(II), Fe(III), Ni(II), Co(II), Zn, As(III), Pb(II), Sb(III) or Bi(III)), cross-reactivity was observed, i.e. the amount of Au measured was either under- or over-estimated. To assess if the biosensor would work with natural samples, soils with different physiochemical properties were spiked with Au-complexes. Subsequently, a selective extraction using 1 M thiosulfate was applied to extract the Au. The results showed that Au could be measured in these extracts with the same accuracy as ICP-MS (P<0.05). This demonstrates that by combining selective extraction with the biosensor system the concentration of Au can be accurately measured, down to a quantification limit of 20 ppb (0.1 µM) and a detection limit of 2 ppb (0.01 µM). |
Keywords: | Escherichia coli Salmonella typhimurium Thiosulfates Gold beta-Galactosidase Soil Colorimetry Biosensing Techniques Operon Lac Operon Genes, Reporter Solid Phase Extraction Electrochemical Techniques Limit of Detection |
Rights: | © 2013 Zammit et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
DOI: | 10.1371/journal.pone.0069292 |
Published version: | http://dx.doi.org/10.1371/journal.pone.0069292 |
Appears in Collections: | Aurora harvest Earth and Environmental Sciences publications Environment Institute publications |
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hdl_80010.pdf | Published version | 1.03 MB | Adobe PDF | View/Open |
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