Dual-Mode Detection of Glyphosate Based on DNAzyme-Mediated Click Chemistry and DNAzyme-Regulated CeO2 Peroxidase-like Activity

In this article, a dual-signal sensor for the fluorescence and colorimetric detection of glyphosate (Gly) is developed based on DNAzyme-mediated click chemistry and DNAzyme-regulated CeO2 peroxidase-like activity. DNAzyme can bind to Cu+, triggering a click chemistry reaction between 3-Azido-7-hydroxycoumarin (AHC) and 3-ethyn-1-ol (BOL), thus generating a strong fluorescence signal at 475 nm. Due to the strong coordination between Gly and Cu2+, the amount of reduced Cu+ decreases, resulting in a weakening of the fluorescence. In addition, Gly can inhibit the catalytic site of CeO2 enzyme activity, while DNAzyme, which does not participate in the click chemistry reaction, can be adsorbed by CeO2, further inhibiting the enzyme activity and reducing the oxidation color change of 3,3′,5,5′-tetramethylbenzidine (TMB). The fluorescence detection limit of this dual-mode sensing platform is 0.15 μg/mL, and the colorimetric detection limit is 0.19 μg/mL. This method has been successfully applied to the detection of Gly in tap water and soybeans, which has a promising application in pesticide residue detection.