A Whole-Cell Biosensor for the Detection of Gold

Carla M. Zammit, Davide Quaranta, Shane Gibson, Anita J. Zaitouna, Christine Ta, Joël Brugger, Rebecca Y. Lai, Gregor Grass, Frank Reith

Research output: Contribution to journalArticle

8 Citations (Scopus)

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).

Original languageEnglish (US)
Article numbere69292
JournalPloS one
Volume8
Issue number8
DOIs
StatePublished - Aug 9 2013

Fingerprint

biosensors
Biosensing Techniques
Biosensors
Gold
gold
Galactosidases
galactosidases
Inductively coupled plasma mass spectrometry
atomic absorption spectrometry
Mass Spectrometry
Industry
Genes
cells
neutron activation analysis
Neutron Activation Analysis
Thiosulfates
thiosulfates
Salmonella
Salmonella enterica
Neutron activation analysis

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

Cite this

Zammit, C. M., Quaranta, D., Gibson, S., Zaitouna, A. J., Ta, C., Brugger, J., ... Reith, F. (2013). A Whole-Cell Biosensor for the Detection of Gold. PloS one, 8(8), [e69292]. https://doi.org/10.1371/journal.pone.0069292

A Whole-Cell Biosensor for the Detection of Gold. / Zammit, Carla M.; Quaranta, Davide; Gibson, Shane; Zaitouna, Anita J.; Ta, Christine; Brugger, Joël; Lai, Rebecca Y.; Grass, Gregor; Reith, Frank.

In: PloS one, Vol. 8, No. 8, e69292, 09.08.2013.

Research output: Contribution to journalArticle

Zammit, CM, Quaranta, D, Gibson, S, Zaitouna, AJ, Ta, C, Brugger, J, Lai, RY, Grass, G & Reith, F 2013, 'A Whole-Cell Biosensor for the Detection of Gold', PloS one, vol. 8, no. 8, e69292. https://doi.org/10.1371/journal.pone.0069292
Zammit CM, Quaranta D, Gibson S, Zaitouna AJ, Ta C, Brugger J et al. A Whole-Cell Biosensor for the Detection of Gold. PloS one. 2013 Aug 9;8(8). e69292. https://doi.org/10.1371/journal.pone.0069292
Zammit, Carla M. ; Quaranta, Davide ; Gibson, Shane ; Zaitouna, Anita J. ; Ta, Christine ; Brugger, Joël ; Lai, Rebecca Y. ; Grass, Gregor ; Reith, Frank. / A Whole-Cell Biosensor for the Detection of Gold. In: PloS one. 2013 ; Vol. 8, No. 8.
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