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Development of electrochemical aptasensor using dendrimers as an immobilization platform for detection of Aflatoxin B1 in food samples

This project focuses on the development of a DNA-aptamer based biosensor, which is referred to as an aptasensor, that would aid in the detection of mycotoxins in foodstuffs. We developed aptamer based biosensor for detection of Aflatoxin B1 (AFB1), a mycotoxin produced by Aspergillus flavus and Aspergillus parasiticus, species of fungi. The characterization of the sensor and detection of aflatoxin B1 was performed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). We tested an electrochemical aptasensor for AFB1 detection through the immobilization of DNA aptamers on the Poly (amido-amine) dendrimers of fourth generation (PAMAM G4) on gold electrode covered by cystamine. The DNA aptamers specific to AFB1 were attached on the PAMAM layer covalently by means of glutaraldehyde. The range of AFB1 concentrations was selected as target interval for further utilization of the biosensor in food samples. The aptasensor has been tested in certificated samples of peanuts as well as in spiked samples of peanuts demonstrating optimal response. The biosensor was also tested in other mycotoxins such as ochratoxin A (OTA) and aflatoxin B2 (AFB2), to investigate non-specific interaction.