Highly Sensitive and Selective Detection of Food Toxin Using Three Functional DNA Hairpins

By combining three kinds of DNA hairpins (one involving both aptamer sequence and trigger sequence, and the other two to amplify the signal by hybridization chain reaction), a food toxin ochratoxin A (OTA) was selectively detected with a remarkably high sensitivity. The signal was visualized with the use of the peroxidase-like function of G-quadruplexes that were formed from the terminal sequences of two adjacent fragments in the DNA nanowire. Even 0.08 ppb of OTA was successfully detected.