Rigid DNA tetrahedral scaffold-mediated dumbbell hybridization chain reaction for the ultrasensitive electrochemical detection of ochratoxin A

Abstract

Herein, an innovative and label-free electrochemical biosensing platform based on a rigid DNA tetrahedral scaffold (DTS)-mediated dumbbell hybridization chain reaction (DHCR) system (DMD system) was constructed for the ultrasensitive detection of ochratoxin A (OTA) related to food safety. Impressively, a small amount of target OTA could be converted into a large amount of secondary target S1 by Exonuclease III-assisted cycling, achieving efficient amplification of the target. In addition, due to the spatial domain-limiting effect, ordered spatial distribution, and superior mechanical rigidity of DTS, the DHCR mediated by DTS could efficiently generate a large amount of compact and dense DNA nanostructures to carry more signaling molecules for a notable electrochemical signal, thereby markedly enhancing the sensitivity of the electrochemical biosensor. Consequently, the developed electrochemical biosensing platform achieved ultrasensitive detection of OTA with a detection limit of 1.06 fg/mL, which was lower than those of reported studies, and was successfully applied to detect OTA in red wine and coffee. As a result, this strategy constructed a high-performance sensing platform based on a novel DMD system, which offered a promising approach for the ultrasensitive detection of toxins in food and the environment.