Impedimetric Label-Free Immunosensor on Disposable Modified Screen-Printed Electrodes for Ochratoxin A.

Francesca Malvano,Donatella Albanese,Roberto Pilloton,Emanuela Esposito,Alessio Crescitelli

doi:10.3390/bios6030033

Abstract

An impedimetric label-free immunosensor on disposable screen-printed carbon electrodes (SPCE) for quantitative determination of Ochratoxin A (OTA) has been developed. After modification of the SPCE surface with gold nanoparticles (AuNPs), the anti-OTA was immobilized on the working electrode through a cysteamine layer. After each coating step, the modified surfaces were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The capacitance was chosen as the best parameter that describes the reproducible change in electrical properties of the electrode surface at different OTA concentrations and it was used to investigate the analytical parameters of the developed immunosensor. Under optimized conditions, the immunosensor showed a linear relationship between 0.3 and 20 ng/mL with a low detection limit of 0.25 ng/mL, making it suitable to control OTA content in many common food products. Lastly, the immunosensor was used to measure OTA in red wine samples and the results were compared with those registered with a competitive ELISA kit. The immunosensor was sensitive to OTA lower than 2 μg/kg, which represents the lower acceptable limit of OTA established by European legislation for common food products.

Highlights

Mycotoxins are a large and varied group of mold-secondary metabolites with common features because they are all produced by fungi and have toxic effects against vertebrates and other organisms.Mycotoxins affect a broad range of agricultural products, including cereals, cereal-based foods, dried fruits, wine, milk, coffee beans, cocoa, or meat products, which are the basis of the economies of many developing countries [1]
Ochratoxin A (OTA) is one of the most abundant mycotoxins that contaminates food products; it is found in tissue and organs of animals, including human blood and breast milk, and is known to produce nephrotoxic, teratogenic, carcinogenic, and immune toxic activity in several animal species [3]
The first immunosensor for OTA detection based on electrochemical impedance spectroscopy (EIS) with a modified screen-printed carbon electrodes (SPCE) is reported

Summary

Introduction

Mycotoxins are a large and varied group of mold-secondary metabolites with common features because they are all produced by fungi and have toxic effects against vertebrates and other organisms. Mycotoxins affect a broad range of agricultural products, including cereals, cereal-based foods, dried fruits, wine, milk, coffee beans, cocoa, or meat products, which are the basis of the economies of many developing countries [1]. Ochratoxin A (OTA) is one of the most abundant mycotoxins that contaminates food products; it is found in tissue and organs of animals, including human blood and breast milk, and is known to produce nephrotoxic, teratogenic, carcinogenic, and immune toxic activity in several animal species [3]. OTA affects humans mainly through consumption of improperly stored food products, causing cancer.

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