The effect of adjacent double-strand DNA on the G-triplex-ThT complex fluorescence intensity enhancement and its application in TNOS and Hg2+ detection.

ABSTRACT

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 Hg2+ were detected. The intermolecular duplex hybridization (e.g., TNOS gene and its complementary DNA), or the intramolecular mismatched thymine (T)-Hg2+-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 Hg2+ in lake water.