Methods, kits, and oligonucleotides used in the detection of the coronavirus strain, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are disclosed. In some aspects, the oligonucleotides are primers or probes used in the described methods or kits. The oligonucleotide consists of 40 or less nucleotides and has a nucleotide sequence that consists essentially of, or is a variant of, the nucleotide sequence of: SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:5, SEQ ID NO:6, or SEQ ID NO:7. In some embodiments, the oligonucleotide is modified with an internal spacer or a detectable label. For example, the 5′ terminus is labeled with a fluorophore and the 3′ terminus is complexed to a quencher of fluorescence of said fluorophore. In some embodiments, the nucleotide sequence of the oligonucleotide further comprises a universal tail sequence.

Methods, kits, and oligonucleotides used in the detection of the coronavirus strain, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are disclosed. In some aspects, the oligonucleotides are primers or probes used in the described methods or kits. The oligonucleotide consists of 40 or less nucleotides and has a nucleotide sequence that consists essentially of, or is a variant of, the nucleotide sequence of: SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:5, SEQ ID NO:6, or SEQ ID NO:7. In some embodiments, the oligonucleotide is modified with an internal spacer or a detectable label. For example, the 5′ terminus is labeled with a fluorophore and the 3′ terminus is complexed to a quencher of fluorescence of said fluorophore. In some embodiments, the nucleotide sequence of the oligonucleotide further comprises a universal tail sequence.

The present disclosure describes a CRISPR nuclease cascade assay that can detect one or more target nucleic acids of interest of interest at attamolar (aM) (or lower) limits in about 10 minutes or less without the need for amplifying the target nucleic acids of interest. The CRISPR cascade assays utilize signal amplification mechanisms comprising various components including CRISPR nucleases, guide RNAs (gRNAs), blocked nucleic acid molecules, blocked primer molecules, and reporter moieties.

The present disclosure describes a CRISPR nuclease cascade assay that can detect one or more target nucleic acids of interest of interest at attamolar (aM) (or lower) limits in about 10 minutes or less without the need for amplifying the target nucleic acids of interest. The CRISPR cascade assays utilize signal amplification mechanisms comprising various components including CRISPR nucleases, guide RNAs (gRNAs), blocked nucleic acid molecules, blocked primer molecules, and reporter moieties.

The present disclosure describes a CRISPR nuclease cascade assay that can detect one or more target nucleic acids of interest of interest at attamolar (aM) (or lower) limits in about 10 minutes or less without the need for amplifying the target nucleic acids of interest. The CRISPR cascade assays utilize signal amplification mechanisms comprising various components including CRISPR nucleases, guide RNAs (gRNAs), blocked nucleic acid molecules, blocked primer molecules, and reporter moieties.

Methods and compositions for in situ detection of circular RNA in a tissue sample are provided.

The present disclosure relates to methods and compositions involving HCR reactions that involve initiators that are split into two or more parts. Effective HCR is dependent upon two or more of these split initiators being brought into proximity (e.g., via binding events mediated by a target) such that a full initiator is formed that is capable of triggering HCR signal amplification.

The invention relates to methods of multiplex detection of a plurality of target nucleic acids by contacting a sample with an acid reagent to remove bound nucleic acid detection systems, thereby allowing the same detection systems to be used again to detect different target nucleic acids and to provide for higher levels of multiplexing. The invention also relates to kits containing an acid reagent and optionally probes for detection of target nucleic acids.

The invention relates to methods of multiplex detection of a plurality of target nucleic acids by contacting a sample with an acid reagent to remove bound nucleic acid detection systems, thereby allowing the same detection systems to be used again to detect different target nucleic acids and to provide for higher levels of multiplexing. The invention also relates to kits containing an acid reagent and optionally probes for detection of target nucleic acids.

The present disclosure describes compositions of matter comprising a ribonucleoprotein complex comprising a nucleic acid-guided nuclease and a guide RNA, and further comprising and a blocking nucleic acid molecule represented by Formula I, wherein Formula I in the 5′-to-3′ direction comprises: A-(B-L).sub.J-C-M-T-D; wherein A is 0-15 nucleotides in length; B is 4-12 nucleotides in length; L is 3-25 nucleotides in length; J is an integer between 1 and 10; C is 4-15 nucleotides in length; M is 1-25 nucleotides in length or is absent, wherein if M is absent then A-(B-L).sub.J-C and T-D are separate nucleic acid strands; T is 17-135 nucleotides in length and comprises at least 50% sequence complementarity to B and C; D is 0-10 nucleotides in length and comprises at least 50% sequence complementarity to A; and wherein the blocking nucleic acid molecule comprises a sequence complementary to a gRNA.