Exploring the fluorescence enhancement of the split G-quadruplex towards DNA-templated AgNCs and their application in omethoate detection.

Herein, the fluorescent enhancement of the split G-quadruplex (G4) towards DNA-templated AgNCs (DNA-AgNCs) was systematically studied. It was shown that the two G-rich probes with the ratio of the guanine (G) bases of 6 : 6 was the best split mode, and the spacer length of the zero T base at both two sides could present the optimal distance between the AgNCs and split G4. In light of these results, a split G4 coupled with DNA-AgNCs for omethoate (OME) detection was successfully fabricated. The developed fluorescent aptasensor could sense OME in the concentration range of 5-200 nM with a detection limit of 4.16 nM. Moreover, the aptasensor performed well in real-sample detection.