Accurate Molecular Sensing based on a Modular and Customizable CRISPR/Cas-Assisted Nanopore Operational Nexus (CANON).

Solid-state nanopore is a promising single molecular detection technique, but is largely limited by relatively low resolution to small-size targets and laborious design of signaling probes. Here we establish a universal, CRISPR/Cas-Assisted Nanopore Operational Nexus (CANON), which can accurately transduce different targeting sources/species into different DNA structural probes via a "Signal-ON" mode. Target recognition activates the cleavage activity of a Cas12a/crRNA system and then completely digest the blocker of an initiator. The unblocked initiator then triggers downstream DNA assembly reaction and generate a large-size structure easy for nanopore detection. Such integration of Cas12a/crRNA with DNA assembly establishes an accurate correspondence among the input targets, output DNA structures, and the ultimate nanopore signals. We demonstrated dsDNA, long RNA (i.e., Flu virus gene), short microRNA (i.e., let-7d) and non-nucleic acids (i.e., Pb) as input paradigms. Various structural assembly reactions, such as hybridization chain reaction (HCR), G-HCR and duplex polymerization strategy (DPS), are adapted as outputs for nanopore signaling. Simultaneous assay is also verified via transferring FluA and FluB genes into HCR and G-HCR, respectively. CANON is thus a modular sensing platform holding multiple advantages such as high accuracy, high resolution and high universality, which can be easily customized into various application scenes.