Issue 5, 2013
From the journal:

Analyst

Carbon microarrays for the direct impedimetric detection of Bacillus anthracis using Gamma phages as probes†

Arghavan Shabani,ab   Christophe A. Marquette,*c   Rosemonde Mandevillea  and  Marcus F. Lawrenceb  

* Corresponding authors

a Biophage Pharma, 6100 Royalmount, Montreal, QC, Canada H4P 2R2

b Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke W., Montreal, QC, Canada H4B 1R6

c Institut de Chimie et Biochimie Moléculaires et Supramoléculaires Equipe Génie Enzymatique, Membranes Biomimétiques et Assemblages Supramoléculaires (GEMBAS), Université Lyon 1, CNRS 5246, ICBMS, Bâtiment CPE 43, bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France
E-mail: christophe.marquette@univ-lyon1.fr

Abstract

A direct and efficient impedimetric method is presented for the detection of Bacillus anthracis Sterne vegetative cells, using Gamma phages as probes attached to screen-printed carbon electrode microarrays. The carbon electrodes were initially functionalized through cyclic-voltammetric reduction of a nitro-aryl diazonium moiety, followed by further reduction of nitro groups to amino groups, and finally by treatment with glutaraldehyde. Functionalization (probe immobilization) using Gamma phages was verified by XPS and TOF-SIM experiments. The Gamma phage-modified microarrays were then used to detect B. anthracis Sterne bacteria in aqueous electrolyte media. Faradaic impedimetric detection of bacteria in KCl solution containing the ferri/ferro cyanide redox couple shows a gradual increase in Z′ (real impedance) values, taken from the extrapolation of the linear portion of Nyquist plots in the low frequency range, for sensors placed in contact with increasing concentrations of B. anthracis. ΔZ′ values vary from 700 to 5300 Ohms for bacteria concentrations ranging from 102 to 108 cfu mL−1. These shifts in Z′ are attributed to a decrease in diffusion controlled charge transfer to the electrode surface following capture of intact B. anthracis. No significant ΔZ′ was observed for control experiments using E. coli. K12 as a non-specific target, even at a concentration of 108 cfu mL−1.

Graphical abstract: Carbon microarrays for the direct impedimetric detection of Bacillus anthracis using Gamma phages as probes

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Article information

DOI
https://doi.org/10.1039/C3AN36830K
Article type
Paper
Submitted
10 Dec 2012
Accepted
09 Jan 2013
First published
09 Jan 2013

Analyst, 2013,138, 1434-1440

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Carbon microarrays for the direct impedimetric detection of Bacillus anthracis using Gamma phages as probes

A. Shabani, C. A. Marquette, R. Mandeville and M. F. Lawrence, Analyst, 2013, 138, 1434 DOI: 10.1039/C3AN36830K

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