About this Journal Submit a Manuscript Table of Contents
ISRN Electrochemistry
Volume 2013 (2013), Article ID 367872, 9 pages
http://dx.doi.org/10.1155/2013/367872
Research Article

An Immunosensor for Pathogenic Staphylococcus aureus Based on Antibody Modified Aminophenyl-Au Electrode

1Institute of Analytical Sciences, University of Lyon, UMR CNRS 5280, 5 rue de la Doua, 69100 Villeurbanne, France
2Laboratory of Interfaces and Advanced Materials, Faculty of Sciences, University of Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia
3Laboratory of Analysis, Treatment and Valorisation of Pollutants of Environment and of Products, Faculty of Pharmacy, University of Monastir, 5019 Monastir, Tunisia

Received 8 August 2013; Accepted 9 September 2013

Academic Editors: S. Arya and E. M. Richter

Copyright © 2013 Amani Chrouda et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The objective of this work is to elaborate an immunosensing system which will detect and quantify Staphylococcus aureus bacteria. A gold electrode was modified by electrografting of 4-nitrophenyl diazonium, in situ synthesized in acidic aqueous solution. The immunosensor was fabricated by immobilizing affinity-purified polyclonal anti S. aureus antibodies on the modified gold electrode. Cyclic voltammetry (CV) and Faradaic Electrochemical Impedance Spectroscopy (EIS) were employed to characterize the stepwise assembly of the immunosensor. The performance of the developed immunosensor was evaluated by monitoring the electron-transfer resistance detected using Faradaic EIS. The experimental results indicated a linear relationship between the relative variation of the electron transfer resistance and the logarithmic value of S. aureus concentration, with a slope of 0.40 ± 0.08 per decade of concentration. A low quantification limit of  CFU per ml and a linear range up to  CFU per mL were obtained. The developed immunosensors showed high selectivity to Escherichia coli and Staphylococcus saprophyticus.