Abstract
The detection of aflatoxin B1 (AFB1) has recently garnered much attention on the issue of food safety. In this study, a novel and sensitive aptasensor towards AFB1 is proposed using an Exonuclease III (Exo III)-integrated signal amplification strategy. This reported sensing strategy is regulated by aptamer-functionalized nanobeads that can target AFB1; furthermore, complementary DNA (cDNA) strands can lock the immobilized aptamer strands, preventing the signal amplification function of Exo III in the absence of AFB1. The presence of AFB1 triggers the displacement of cDNA, which will then activate the Exo III-integrated signal amplification procedure, resulting in the generation of a guanine (G)-rich sequence to form a G-4/hemin DNAzyme, which can catalyze the substrate of ABTS to produce a green color. Using this method, a practical detection limit of 0.0032 ng/mL and a dynamic range of detection from 0.0032 to 50 ng/mL were obtained. Additionally, the practical application of the established sensing method for AFB1 in complex matrices was demonstrated through recovery experiments. The recovery rate and relative standard deviations (RSD) in three kinds of cereal samples ranged from 93.83% to 111.58%, and 0.82% to 7.20%, respectively, which were comparable with or better than previously reported methods.
Highlights
Aflatoxin B1 (AFB1) produced by the Aspergillus species is one of the most toxic mycotoxins occurring in agricultural products, and it can directly contaminate cereals like corn, wheat, barley, millet, and their by-products [1,2,3]
Numerous analytical techniques have been employed for quantitative determination of AFB1, such as thin layer chromatography (TLC) [7], high performance liquid chromatography (HPLC) [8], and liquid chromatography-mass spectrometry (LCMS) [9]
In the presence of AFB1, the aptamer immobilized on the magnetic nanobead opens to combine with the target AFB1, inducing the conformational change of the aptamer and releases its complementary primer chain from the magnetic nanobeads
Summary
Aflatoxin B1 (AFB1) produced by the Aspergillus species is one of the most toxic mycotoxins occurring in agricultural products, and it can directly contaminate cereals like corn, wheat, barley, millet, and their by-products [1,2,3] Exposure to this toxic substance can lead to serious consequences for human health, including hepatotoxicity, carcinogenicity, teratogenicity, and mutagenicity [4,5]. These instrumental analytical methods have high sensitivity, good repeatability, and strong stability for AFB1 detection They constantly require expensive instruments and highly trained personnel, and the complex sample processing stage is cumbersome and time-consuming. Issues such as these restrict their applications in the economical and easy-to-use monitoring of AFB1 [10]
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