Integrating magnetic metal-organic frameworks-based sample preparation with microchannel resistance biosensor for rapid and quantitative detection of aflatoxin B1

Aflatoxin B1, a secondary metabolite produced by fungi, is one of the most toxic mycotoxins that poses a major food security and public health threat worldwide. Effective sample pretreatment and high sensitivity detection techniques are urgently needed due to its trace amount in complex samples. Herein, an integrated detection strategy was developed by combining Mg/Zn-metal organic framework-74 modified Fe3O4 magnetic nanoparticles (Mg/Zn-MOF-74 @Fe3O4 MNPs)-based sample preparation and microchannel resistance biosensor for rapid and highly sensitive detection of aflatoxin B1 in food samples. The synthesis and characterization of Mg/Zn-MOF-74 @Fe3O4 MNPs was reported, which exhibited efficient separation and enrichment capacity when exposed to complex grain samples. The competitive immunoassay-based microchannel resistance biosensor enabled specific and high-sensitive analysis of aflatoxin B1 by using current as a readout, which caused by the blocking effect between the functionalized-polystyrene microspheres and microchannel. Under optimized conditions, this biosensor was capable to quantitatively analysis aflatoxin B1 from 10 pg/mL to 20 ng/mL, and with a limit of detection of 4.75 pg/mL. This integrated detection strategy has been tested for the quantitative detection of aflatoxin B1 in grain samples that is a potential protocol for food safety control and environmental monitoring.