Thioflavin T as a noncovalent reporter for a label-free, non-enzymatic, catalytic DNA amplifier

DNA-DNA reactions can be monitored with a label-free fluorogenic reaction. Guanosine-rich, single-stranded DNA oligonucleotides bind to thioflavin-T (ThT) and enhance the fluorescence of the dye. We discovered a novel DNA sequence that produces fluorescence upon binding to ThT. We denote this oligonucleotide ThTSignal. We use ThTSignal as a label-free reporter for the activity of several designed DNA-DNA reactions (DNA circuits). The DNA circuits conditionally produce the ThTSignal oligonucleotide by association or by liberating the ThTSignal oligonucleotide from double-stranded DNA. This strategy offers label-free, cost-effective, fluorogenic detection of the molecular beacon reaction, split reporter reaction, one-step strand displacement reaction, and the entropy-driven amplifier reaction (a catalytic DNA circuit).