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Journal of Sensors
Volume 2009, Article ID 746548, 12 pages
Research Article

Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles

1Laboratoire des Sciences Analytiques (UMR CNRS 5180), Université de Lyon, Batiment Raulin, Université de Claude Bernard, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex, France
2Laboratoire AMPERE (UMR CNRS 5180), INSA de Lyon, 69621 Villeurbanne, France
3Unité de Recherche de Physique des Semiconducteurs et Capteurs, IPEST, La Marsa 2070, Tunisia

Received 30 December 2008; Revised 18 May 2009; Accepted 8 July 2009

Academic Editor: Wojtek Wlodarski

Copyright © 2009 Imen Hafaid 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.


This work has explored the development of impedimetric immunosensors based on magnetic iron nanoparticles (IrNP) functionalized with streptavidin to which a biotinylated FAB part of the antibody has been bound using a biotin-streptavidin interaction. SPR analysis shows a deviation on the measured (angle) during antigen-antibody recognition whereas label free detection using by EIS allows us to monitor variation of polarization resistance. Before detection, layers were analyzed by FTIR and AFM. Compared to immobilization of antibody on bare gold surface using aminodecanethiol SAM, antibody immobilization on nanoparticles permitted to reach lower detection limit: 500 pg/ml instead of 1 ng/ml to in the case of EIS and 300 ng/ml instead of 4.5 g/ml in the case of SPR. Thus, it permitted to improve the sensitivity: from 257.3  to 1871  in the case of EIS and from to in the case of SPR.