Target-induced DNA machine amplification strategy for high sensitive and selective detection of biotoxin

Abstract

Aflatoxin M1 (AFM1) is classified as group 1 carcinogen and can cause fetal disease and chronic illness. High sensitive and selective detection of AFM1 is critical for food safety and human health. Herein, a target-induced DNA machine amplification assay combining high specificity of aptamer recognition was developed for fluorescence detection of AFM1 in an enzyme-free and label-free condition. Once AFM1 was added into the biosensing system, aptamer would trap AFM1 and then release primer DNA to trigger the designed DNA machine. The DNA machine would continuously produce guanine-rich (G-rich) DNA segments to form G-quadruplex (G4) configuration, which can outstandingly augment fluorescence response of N-methyl-mesoporphyrin (NMM). With the signal amplification strategy, limit of detection (LOD) reaches as low as 0.01 ng mL−1. Meanwhile, the DNA machine-based sensing system presents excellent specificity and can distinguish AFM1 from other biotoxins. The developed strategy provides a new way for high sensitive and selective detection of AFM1 with low cost for real sample detection.