A G-quadruplex dual-signal strategy for on-site detection of OTA in moldy foods

Ochratoxin A (OTA) is a mycotoxin that is prevalent in contaminated foods and poses a substantial risk. Currently, OTA detection methods rely primarily on single-signal output, rendering them vulnerable to interference. Dual-signal methods can effectively circumvent the aforementioned issues, but the diversity of output signals is limited and needs to be expanded immediately, and there is an extreme lack of on-site detection methods for OTA in crops. In this study, G-quadruplex (G4)-hemin was introduced into a temperature panel to construct a G4 dual-signal (colorimetric and temperature) sensing system, which enables a highly sensitive, on-site, rapid detection of OTA with detection limits of 9.7 nM for colorimetric and 15.7 nM for temperature, respectively. More importantly, this system successfully achieved on-site detection of OTA in moldy corn and wheat. The constructed·G4·dual-signal sensing system own the advantages of simplicity, accuracy, and high sensitivity, demonstrating the great promise in home testing.