DNAzyme-Triggered Equilibrium Transfer with Self-Activated CRISPR-Cas12a Biosensor Enables One-Pot Diagnosis of Nucleic Acids.

Integrating recombinase-polymerase amplification (RPA) with CRISPR-Cas12a holds significant potential to simplify and improve nucleic acid diagnostic procedures. However, current strategies face limitations, such as complexity, reduced efficiency, and potential compromises in Cas12a activity. In response, we developed a DNAzyme-triggered equilibrium transfer with a self-activated CRISPR-Cas12a biosensor (DESCRIBER) for integrated nucleic acid detection. This platform features varying balance points to minimize interference between RPA and Cas12a in one pot and maximize their activity at different stages. Initially, the reaction focused on RPA, while Cas12a was silenced by circular-crRNA (C-crRNA). Then, DNAzyme, the activator, was generated during the RPA process, which linearizes C-crRNA to activate Cas12a and transfer the equilibrium toward signal readout. Meanwhile, activated Cas12a can further linearize C-crRNA to promote self-activation and accelerate equilibrium transfer. According to this principle, highly sensitive detection of the HIV-1 genome, as low as 500 CPs/mL, was achieved within 1 h while maintaining universality in detecting common subtypes and specificity against opportunistic infectious pathogens. Compared with qRT-PCR, it also exhibited good accuracy in detecting 35 spiked samples. Overall, we believe that the proposed strategy will enhance existing CRISPR systems to promote their practical applications in clinical diagnosis.