Development of quantitative magnetic beads-based flow cytometry fluorescence immunoassay for aflatoxin B1

Abstract

Aflatoxins are secondary metabolites produced by Aspergillus fungi, and aflatoxin B1 (AFB1) is the most potent carcinogen among these compounds. As one of the most widely distributed hazardous chemicals in nature, it can be introduced into the human body via the food chain, thereby posing a threat to human health. Therefore, improving the detection level of AFB1 has become a critical control point for food safety, medical examination, import and export inspection, and quarantine diagnosis. Herein, we designed a magnetic beads (MBs)-based flow cytometry fluorescence immunoassay (FCMFI). In this assay, we developed a magnetic bead modified with BSA–AFB1 to form a competitive immune pattern in the sample solution with free AFB1. A secondary antibody labeled with fluorescein isothiocyanate (FITC) binds to the above targets to provide a signal for the fluorescent immunoassay. Changes in fluorescence intensity received by the flow cytometer can be used to quantify the AFB1 content. In this work, the limit of detection (LOD) of FCMFI was 0.2034 μg/L for AFB1 in the buffer, and the limit of quantitation (LOQ) was 0.5659 μg/L. We also optimized some reaction conditions. Under the best conditions, the developed FCMFI method could analyze AFB1 efficiently with considerable sensitivity. The developed FCMFI was verified by comparing with the colorimetric indirect enzyme linked immunosorbent assay (id-ELISA), and commercial kit. The results show that the FCMFI method has excellent performance features, such as high sensitivity and low LOD. Hence, the convenience and reliability of the developed AFB1 detection method were fully demonstrated.