Integrating magnetic metal-organic frameworks-based sample preparation with microchannel resistance biosensor for...

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.