Label-free impedimetric immunosensor for sensitive detection of ochratoxin A

Abd Elgawad Radi, Xavier Muñoz-Berbel, Vasilica Lates, Jean Louis Marty

    Research output: Contribution to journalArticleResearchpeer-review

    132 Citations (Scopus)


    A novel label-free electrochemical impedimetric immunosensor for sensitive detection of ochratoxin A (OTA) was reported. A two-step reaction protocol was elaborated to modify the gold electrode. The electrode was first derivatized by electrochemical reduction of in situ generated 4-carboxyphenyl diazonium salt (4-CPDS) in acidic aqueous solution yielded stable 4-carboxyphenyl (4-CP) monolayer. The ochratoxin A antibody was then immobilized making use of the carbodiimide chemistry. The steps of the immunosensor elaboration and the immunochemical reaction between ochratoxin A and the surface-bound antibody were interrogated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The impedance change, due to the specific immuno-interaction at the immunosensor surface was utilized to detect ochratoxin A. The increase in electron-transfer resistance (ΔRet) values was linearly proportional to the concentration of OTA in the range of 1-20 ng mL-1, with a detection limit of 0.5 ng mL-1. © 2008 Elsevier B.V. All rights reserved.
    Original languageEnglish
    Pages (from-to)1888-1892
    JournalBiosensors and Bioelectronics
    Issue number7
    Publication statusPublished - 15 Mar 2009


    • Diazonium salt
    • Electrochemical impedance spectroscopy
    • Immunosensor
    • Ochratoxin A


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