Abstract
We developed a new biosensor for the detection of aflatoxin B1(AFB1) based on the interaction of gold nanoparticles (AuNPs) with the aptamer. Aggregation of AuNPs was induced by desorption of the AFB1 binding aptamer from the surface of AuNPs as a result of the aptamer target interaction leading to the color change of AuNPs from red to purple. The linear range of the colorimetric aptasensor covered a large variation of AFB1 concentrations from 80 to 270 nM and the detection limit of 7 nM was obtained. Also, the catalytic activity of the aggregated AuNPs greatly enhanced the chemiluminescence (CL) reaction, where the detection limit was determined at 0.5 nM with a regression coefficient of R(2) = 0.9921. We have also shown that the sensitivity of detection was increased by employing CL and using the catalytic activity of aggregated AuNPs, during luminol-hydrogen peroxide reaction. Therefore the proposed nanobiosensor was demonstrated to be sensitive, selective, and simple, introducing a viable alternative for rapid screening of toxin in foods.
Highlights
Aflatoxins (AF) are toxic compounds which are produced as secondary metabolites by the fungi of Aspergillus flavus and and Aspergillus parasiticus growing on a variety of agricultural products.[1]
Nan et al reported an approach based on real time-quantitative polymerase chain reaction (PCR) for detection of aflatoxin B1 (AFB1) with a limit of detection of 25 fg · mL–1.25 Very recently, an electrochemical aptasensor for detection of AFB1 developed through layer coating of cystamine, PAMAM G4 dendrimers and DNA aptamers specific to AFB1 has been reported by Castillo and co-authors
Since the analyte generated alteration of the LSPR properties of AuNPs and the consequent color changes from dispersed state to aggregation under different condiat about 520 nm appeared (Fig. 1). This phenomenon suggested that the aptamer AFB1 could serve as a stabilizer and protected AuNPs from salt-induced aggregation.[32]
Summary
Aflatoxins (AF) are toxic compounds which are produced as secondary metabolites by the fungi of Aspergillus flavus and and Aspergillus parasiticus growing on a variety of agricultural products.[1]. The assay allowed detection of AFB1 with LOD 0.35 nM and it has been validated in spiked corn samples.[24] Nan et al reported an approach based on real time-quantitative polymerase chain reaction (PCR) for detection of AFB1 with a limit of detection of 25 fg · mL–1.25 Very recently, an electrochemical aptasensor for detection of AFB1 developed through layer coating of cystamine, PAMAM G4 dendrimers and DNA aptamers specific to AFB1 has been reported by Castillo and co-authors This biosensor achieved high sensitivity (LOD 0.4 nM) and it was tested for quantifying AFB1 levels in contaminated peanuts.[26]. The detection could be performed by monitoring the color change of the AuNPs even with naked eyes and by enhancement of chemiluminescence intensity
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