The effect of adjacent double-strand DNA on the G-triplex-ThT complex fluorescence intensity enhancement and its application in TNOS and Hg detection.

In this paper, we have found that adjacent double-strand DNA (dsDNA) can enhance the fluorescence intensity of the G-triplex (G31)-thioflavin T (ThT) complex. By connecting the newly formed dsDNA with the G31 sequence, terminator nopaline synthase (TNOS) gene and Hg were detected. The intermolecular duplex hybridization (e.g., TNOS gene and its complementary DNA), or the intramolecular mismatched thymine (T)-Hg-T pairs induced the formation of dsDNA with planar morphology, which resulted in the increased binding capacity of adjacent G31 to ThT, as well as the enhanced fluorescence intensity of G31-ThT complex. A versatile 'turn-on' fluorescence scaffold was developed for discriminating transgenic and non-transgenic soybeans and detecting Hg in lake water.