title: A highly sensitive impedimetric label free immunosensor for Ochratoxin measurement in cocoa beans.
abstract: In this work the development and optimization of an impedimetric label free immunosensor for the detection of Ochratoxin A (OTA) is reported. Two antibody immobilization methods (oriented and not oriented) were compared highlighting a lower limit of detection (5pg/ml) for the not oriented immobilization but a closer linear range in contrast to oriented anti-OTA immunosensors which showed linearity in the range of 0.01-5ng/mL OTA. The analysis of the Atomic Force Microscopy (AFM) images showed two different nanostructures indicating that the use of oriented immobilization created a more ordered and highly dense antibody surface. Finally the oriented immunosensor was used to quantify OTA in spiked cocoa bean samples and the results were compared with those registered with competitive ELISA kit. The immunosensor was sensitive to OTA lower than 2μg/kg that represents the lower acceptable limit of OTA established by European legislation for the common food products.
authors.affiliation: Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Malvano
authors.affiliation: Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy. Electronic address: dalbanese@unisa.it.
authors.forename: Donatella
authors.initials: D
authors.lastname: Albanese
authors.affiliation: Institute of Atmospheric Pollution Research of the National Council of Research (CNR), Via Salaria, Montelibretti, Roma, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pilloton
authors.affiliation: Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy.
authors.forename: Marisa
authors.initials: M
authors.lastname: Di Matteo
mesh_terms: D000941:Antigens / Q000737:chemistry; D002099:Cacao / Q000737:chemistry*; D017097:Electric Impedance; D004563:Electrochemistry / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D005506:Food Contamination / Q000032:analysis*; D057230:Limit of Detection; D018625:Microscopy, Atomic Force / Q000379:methods; D049329:Nanostructures / Q000737:chemistry; D009793:Ochratoxins / Q000032:analysis* / Q000737:chemistry; D012639:Seeds / Q000737:chemistry*
chemical_list: D000941:Antigens; D009793:Ochratoxins; C025589:ochratoxin A
keywords: Atomic Force Microscopy; Electrochemical Impedance Spectroscopy; Immunosensor; Ochratoxin A