CRISPR/Cas12a-Triggered Chemiluminescence Enhancement Biosensor for Sensitive Detection of Nucleic Acids by Introducing a Tyramide Signal Amplification Strategy.

CRISPR-based biosensors have attracted increasing attention in accurate and sensitive nucleic acid detection. In this work, we report a CRISPR/Cas12a-triggered chemiluminescence enhancement biosensor for the ultrasensitive detection of nucleic acids by introducing tyramide signal amplification for the first time (termed CRICED). The hybrid chain DNA (crDNA) formed by NH2-capture DNA (capDNA) and biotin-recognition DNA (recDNA) was preferentially attached to the magnetic beads (MBs), and the streptavidin-HRP was subsequently introduced to obtain MB@HRP-crDNA. In the presence of the DNA target, the activated CRISPR/Cas12a is capable of randomly cutting initiator DNA (intDNA) into vast short products, and thus the fractured intDNA could not trigger the toehold-mediated DNA-strand displacement reaction (TSDR) event with MB@HRP-crDNA. After the addition of tyramine-AP and H2O2, abundant HRP-tyramine-AP emerges through the covalent attachment of HRP-tyramine, exhibiting enhanced chemiluminescence (CL) signals or visual image readouts. By virtue of this biosensor, we achieved high sensitivity of synthetic DNA target and amplified DNA plasmid using recombinase polymerase amplification (RPA) as low as 17 pM and single-copy detection, respectively. Our proposed CRICED was further evaluated to test 20 HPV clinical samples, showing a superior sensitivity of 87.50% and specificity of 100.00%. Consequently, the CRICED platform could be an attractive means for ultrasensitive and imaging detection of nucleic acids and holds a promising strategy for the practical application of CRISPR-based diagnostics.