Engineering a universal and label-free evaluation method for mycotoxins detection based on strand displacement amplification and G-quadruplex signal amplification

Highly sensitive and selective detection of mycotoxins is of great signification for human health as well as food safety. Herein, we present a universal and label-free detection method for mycotoxins based on strand displacement amplification (SDA) and G-quadruplex-specific fluorescence probe amplification. In this design, detection of target mycotoxin is converted to detect DNA that could be detected easily with high sensitivity through DNA amplification technology for the first time. The technique of SDA is used to amplify the interested DNA. Only in the presence of target mycotoxin, could the procedure of SDA be triggered to generate plenty of “product” DNA. The “product” DNA is assembled to G-quadruplex that could enhance the fluorescence of N-methyl mesoporphyrin IX (NMM) as signal carrier. The strategy can distinguish different target mycotoxins due to the employment of aptamer. The limits of detection (LOD) are 17.79 ng/kg for Aflatoxin M1 (AFM1) and 18.98 ng/kg for Ochratoxin A (OTA), respectively. The provided strategy exhibits great beneficial applications in the fields of foodstuffs safety that is more conducive to human health.