Highly Sensitive Electrochemical Biosensing Strategy Based on Multiple CRISPR/Cas12a Trans -Cleavage Units

Abstract This study presents the assembly of multiple CRISPR/Cas12a units by target-induced hybridization chain reaction (HCR), which is capable of highly sensitive electrochemical detection of target miRNA. The confinement effect of the HCR/Cas12a system is demonstrated, which shows significantly improved cleavage compared with the single Cas12a unit. The tetrahedral DNA nanostructure on the surface of the electrode supports the substrate for cleavage, which possesses the merits of excellent reactivity and accessibility. Because of the dual signal amplification, a low limit of detection down to 2.1 aM is achieved. This method also exhibits excellent specificity, storage stability, and accuracy, indicating its value for miRNA sensing in real biological samples and related clinical applications.