title: Label-free impedimetric immunosensor for sensitive detection of ochratoxin A.
abstract: 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 (DeltaR(et)) values was linearly proportional to the concentration of OTA in the range of 1-20ngmL(-1), with a detection limit of 0.5ngmL(-1).
authors.affiliation: Department of Chemistry, Faculty of Science, Mansoura University, 34517 Dumyat, Egypt.
authors.forename: Abd-Elgawad
authors.initials: AE
authors.lastname: Radi
authors.forename: Xavier
authors.initials: X
authors.lastname: Muñoz-Berbel
authors.forename: Vasilica
authors.initials: V
authors.lastname: Lates
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marty
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D007118:Immunoassay / Q000295:instrumentation*; D009793:Ochratoxins / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
chemical_list: D009793:Ochratoxins; C025589:ochratoxin A