Journal
FOOD CONTROL
Volume 52, Issue -, Pages 9-18Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.foodcont.2014.12.008
Keywords
Aflatoxin B-1; Aptamers; PAMAM dendrimers; Biosensor; Electrochemistry; Atomic force microscopy; Contaminated peanuts
Categories
Funding
- Slovak Research and Development Agency [APVV-0410-10]
- Science Grant Agency VEGA [1/0785/12]
- Centre of Excellence SAS for Functionalized Multiphase Materials (FUN-MAT)
- 7 FP EU [PIRSES-GA-2010-269182]
- Research and Development Operational Programme - ERDF [ITMS: 26240120003]
- Oak Ridge National Laboratories, USA [CNMS2014-33]
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We report an aptamer-based biosensor for detection of aflatoxin B-1 (AFB(1)), a mycotoxin identified as contaminant in food. The sensor is assembled in a multilayer framework that utilizes cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for acquiring the signal response by means of redox indicators: K[Fe(CN)(6)](-3/-4). Poly (amidoamine) dendrimers of fourth generation (PAMAM G4) immobilized on gold electrode covered by cystamine, were employed for attachment of single stranded amino-modified DNA aptamers specific to AFB(1). The cystamine-dendrimers (Cys-PAMAM) layers were compared with other immobilization platforms such as cystamine (Cys), 11-mercaptoundecanoic acid (MUA) and 11-mercaptoundecanoic acid-dendrimers (MUA-PAMAM), being the first approach the most appropriate for producing sensitive and reproducible signal in the range of concentrations 0.1-10 nM AFB(1). The sensor was validated in certified contaminated peanuts extract as well as in spiked samples of peanuts-corn snacks and the sensing response was evaluated and compared in terms of the matrix effect. The aptamer specificity was analyzed by testing the sensor in other mycotoxins such as aflatoxin By (AFB(2)) and ochratoxin A (OTA). The limit of detection achieved by this sensor was LOD = 0.40 +/- 0.03 nM, it was regenerable in 0.2 M glycine-HCI and it did not lose its stability up to 60 h storing at 4 degrees C. Atomic Force Microscopy (AFM) studies were also performed for illustrating individual steps of biosensor assembly. (C) 2014 Elsevier Ltd. All rights reserved.
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