Self-priming amplification-integrated orthogonal CRISPR-Cas system for multiplexed profiling of piRNAs in clinical...

CRISPR/Cas-based biosensors hold great diagnostic potential, but they are often limited in clinical practice by insufficient sensitivity and the lack of multiplexed analysis capability. To address these issues, we develop a self-priming amplification-integrated orthogonal CRISPR-Cas (SPA-OCRISPR) system for multiplexed detection of piRNAs. This assay employs an innovative four-way junction probe that seamlessly integrates target recognition with a primer-free self-priming amplification, significantly simplifying the workflow and enhancing the ligation efficiency. High-fidelity SplitR ligase-mediated transduction guarantees the excellent specificity, efficiently eliminating the need for reverse transcription. The orthogonal trans-cleavage activities of Cas12a and Cas13a are harnessed to generate distinct fluorescent signals with minimal cross-interference for multiplexed analysis. This strategy can achieve attomolar-level sensitivity and good specificity. Moreover, it can successfully quantify breast cancer-associated piRNAs (piR-651 and piR-36026) in clinical tissues, and accurately discriminate cancerous samples from healthy ones. Importantly, this strategy exhibits good generality and it can be extended to detect colorectal cancer-related piRNAs (piR-823 and piR-54265) through simply modifying the recognition sequences of split probes, underscoring its broad potential in multiplexed profiling and clinical cancer diagnostics.