Polystyrene Microsphere-Based Immunochromatographic Assay for Detection of Aflatoxin B1 in Maize.

Jin Wang,Jinxiu Liu,Xiangmei Li,Xing Shen,Hongtao Lei,Ang Zhang

doi:10.3390/bios11060200

Abstract

Aflatoxin B1 (AFB1), a mycotoxin, is hepatotoxic, carcinogenic, and nephrotoxic in humans and animals, and contaminate a wide range of maize. In this study, an immunochromatographic assay (ICA) based on polystyrene microspheres (PMs) was developed for sensitive and quantitative detection of AFB1 in maize. The amounts of PMs, the condition for activating carboxyl groups of PMs, the amount of monoclonal antibody (mAb), and the volume of the immune probe were optimized to enhance the performance PMs-ICA for point-of-care testing of AFB1 in maize. The PMs-ICA showed the cut-off value of 1 ng/mL in phosphate buffer (PB) and 6 µg/kg in maize samples, respectively. The quantitative limit of detection (qLOD) was 0.27 and 1.43 µg/kg in PB and maize samples, respectively. The accuracy and precision of the PMs-ICA were evaluated by analysis of spiked maize samples with recoveries of 96.0% to 107.6% with coefficients of variation below 10%. In addition, the reliability of PMs-ICA was confirmed by the liquid chromatography-tandem mass spectrometry method. The results indicated that the PMs-ICA could be used as a sensitive, simple, rapid point-of-care testing of AFB1 in maize.

Highlights

Aflatoxins (AFTs), a class of mycotoxins, are toxic and carcinogenic secondary metabolites produced by A. flavus, A. parasiticus, and the rare A. nomius [1]
Presents the structure of the test strips, including a sample pad, a nitrocellulose filter (NC) membrane, an absorbent pad, and a PVC plate; the Aflatoxin B1 (AFB1) -bovine serum albumin (BSA) and goat anti-mouse antibody IgG were coated on the NC membrane form the T line and C line, respectively
If there was AFB1 in the samples, AFB1 bound to the polystyrene microspheres (PMs)-Ab conjugates to form a PMs-Ab-AFB1 complex in the well, and the binding sites of monoclonal antibody (mAb) would be firstly occupied by AFB1

Summary

Introduction

Aflatoxins (AFTs), a class of mycotoxins, are toxic and carcinogenic secondary metabolites produced by A. flavus, A. parasiticus, and the rare A. nomius [1]. Aflatoxin B1 (AFB1 ), aflatoxin B2 (AFB2 ), aflatoxin G1 (AFG1 ), and aflatoxin G2 (AFG2 ) are the common AFTs [2], and AFB1 presents hepatotoxic, carcinogenic, and nephrotoxic in humans and animals [3,4,5]. To ensure food safety and protect human health, the maximum allowable limits of AFB1 in maize have been set by many countries and regions. A recent survey showed that AFB1 had a high prevalence in cereals, which, in most of the cases, it exceeded the EC allowed limit [9]. In order to ensure the concentration of AFB1 in maize is less than the maximum allowable limits, it is necessary to develop an accurate, effective detection method to monitor the concentration of AFB1. The common methods for AFB1 detection include instrumental analysis methods and immunoassay

Methods

Results

Conclusion