DNA photonic nanowires with tunable FRET signals on the basis of toehold-mediated DNA strand displacement reactions.

A DNA photonic nanowire with tunable FRET signals was fabricated on the basis of cascaded toehold-mediated DNA strand displacement reactions. Different DNA inputs were added to trigger the reaction network, and the corresponding FRET signals were obtained. Compared to the direct hybridization, this design is sensitive for 2 nM targets within 20 min and also causes color changes of the solution with blue-light excitation. It could also be applied in live cells to monitor MicroRNA with a simple modification which might become a low-cost method for further application in the future.