A whole-cell biosensor for the detection of gold

Zammit, Carla M., Quaranta, Davide, Gibson, Shane, Zaitouna, Anita J., Ta, Christine, Brugger, Joel, Lai, Rebecca Y., Grass, Gregor and Reith, Frank (2013) A whole-cell biosensor for the detection of gold. PLoS One, 8 8: e69292.1-e69292.8. doi:10.1371/journal.pone.0069292

Author Zammit, Carla M.
Quaranta, Davide
Gibson, Shane
Zaitouna, Anita J.
Ta, Christine
Brugger, Joel
Lai, Rebecca Y.
Grass, Gregor
Reith, Frank
Title A whole-cell biosensor for the detection of gold
Journal name PLoS One   Check publisher's open access policy
ISSN 1932-6203
Publication date 2013-08-09
Year available 2013
Sub-type Article (original research)
DOI 10.1371/journal.pone.0069292
Open Access Status DOI
Volume 8
Issue 8
Start page e69292.1
End page e69292.8
Total pages 8
Place of publication San Francisco, CA United States
Publisher Public Library of Science
Language eng
Subject 1100 Agricultural and Biological Sciences
1300 Biochemistry, Genetics and Molecular Biology
2700 Medicine
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).
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
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