Thermo-responsive molecular switches for ATP using hairpin DNA aptamers.

Increasingly detailed structural designs are highlighting the utility of oligonucleotide aptamers for diagnostic systems. The primary and secondary structures of DNA aptamers are responsible for structural displacement upon target binding. We revealed that a hairpin aptamer enabled to capture target ATP only when the aptamer transformed into the open-loop conformation by temperature-induced self-dissociation. The recognition event with conformational transition of the hairpin aptamer on gold was identified by electrochemical impedance spectroscopy. The results presented label-free detections above 37°C with high sensitivity and specificity. The hairpin aptamer as a thermo-responsive ligand has much generality for its use as "smart" nano-switches.