Nucleic acid hybridization buffer formulations and uses thereof are described that yield improvements in hybridization specificity, rate, and efficiency. The buffer formulation composition includes a target nucleic acid; at least one organic solvent having a dielectric constant in the range of no greater than 115; and a pH buffer system, wherein the target nucleic acid is attached to the surface via hybridization to a surface bound nucleic acid tethered to the surface, and wherein the hybridization of the target nucleic acid and surface bound nucleic acid has a high stringency and annealing rate.

Nucleic acid hybridization buffer formulations and uses thereof are described that yield improvements in hybridization specificity, rate, and efficiency. The buffer formulation composition includes a target nucleic acid; at least one organic solvent having a dielectric constant in the range of no greater than 115; and a pH buffer system, wherein the target nucleic acid is attached to the surface via hybridization to a surface bound nucleic acid tethered to the surface, and wherein the hybridization of the target nucleic acid and surface bound nucleic acid has a high stringency and annealing rate.

Provided herein are compositions, methods and systems relating to libraries of polynucleotides such that the libraries allow for accurate and efficient hybridization after binding to target sequences. Further provided herein are probes, blockers, additives, buffers, and methods that result in improved hybridization. Such compositions and methods are useful for improvement of Next Generation Sequencing applications, such as reducing off-target binding or reducing workflow times.

Provided herein are compositions, methods and systems relating to libraries of polynucleotides such that the libraries allow for accurate and efficient hybridization after binding to target sequences. Further provided herein are probes, blockers, additives, buffers, and methods that result in improved hybridization. Such compositions and methods are useful for improvement of Next Generation Sequencing applications, such as reducing off-target binding or reducing workflow times.

The present disclosure relates in some aspects to methods for analyzing a target nucleic acid in a biological sample. In some aspects, provided herein are methods and compositions for detecting a region of interest in a target nucleic acid, wherein hybridization between an interrogatory region of a probe and a region of interest of the target nucleic acid is blocked by a blocking strand unless the interrogatory region is complementary to the region of interest. In some aspects, the methods provided herein increase specificity of detecting a region of interest in a target nucleic acid (e.g., a SNP in an RNA molecule). In some aspects, the presence, amount, and/or identity of a region of interest in a target nucleic acid is analyzed in situ. Also provided are polynucleotides, sets of polynucleotides, compositions, and kits for use in accordance with the methods, for example for RNA-targeting padlock probe-mediated SNP detection.

The present disclosure relates in some aspects to methods for analyzing a target nucleic acid in a biological sample. In some aspects, provided herein are methods and compositions for detecting a region of interest in a target nucleic acid, wherein hybridization between an interrogatory region of a probe and a region of interest of the target nucleic acid is blocked by a blocking strand unless the interrogatory region is complementary to the region of interest. In some aspects, the methods provided herein increase specificity of detecting a region of interest in a target nucleic acid (e.g., a SNP in an RNA molecule). In some aspects, the presence, amount, and/or identity of a region of interest in a target nucleic acid is analyzed in situ. Also provided are polynucleotides, sets of polynucleotides, compositions, and kits for use in accordance with the methods, for example for RNA-targeting padlock probe-mediated SNP detection.

The present invention relates to the use of a single-strand DNA binding protein (SSB) which exhibits at least 50% of its maximum ssDNA binding capability in the presence of 500 mM of sodium ions, to dehybridize a DNA molecule or to prevent hybridisation of a complementary ssDNA, wherein the SSB comprises the amino acid sequence of SEQ ID NO:1 or an amino acid sequence which is at least 75% identical to SEQ ID NO:1, or a functional fragment thereof, and wherein the DNA molecule or ssDNA is present in or exposed to a solution containing one or more of the following (i) at least 350 mM of sodium ions; (ii) at least 50 mM of potassium ions; (iii) at least 150 mM of magnesium ions; or (iv) at least 200 mM of calcium ions.

The present invention relates to the use of a single-strand DNA binding protein (SSB) which exhibits at least 50% of its maximum ssDNA binding capability in the presence of 500 mM of sodium ions, to dehybridize a DNA molecule or to prevent hybridisation of a complementary ssDNA, wherein the SSB comprises the amino acid sequence of SEQ ID NO:1 or an amino acid sequence which is at least 75% identical to SEQ ID NO:1, or a functional fragment thereof, and wherein the DNA molecule or ssDNA is present in or exposed to a solution containing one or more of the following (i) at least 350 mM of sodium ions; (ii) at least 50 mM of potassium ions; (iii) at least 150 mM of magnesium ions; or (iv) at least 200 mM of calcium ions.

Embodiments disclosed herein include devices, methods, and systems for direct, selective, and sensitive detection of single-stranded and double-stranded target DNA sequences from various sources using a Cas12a protein. When activated by binding a target DNA sequence, the Cas12a cleaves a tether releasing a reporter molecule that may then be detected. In some embodiments, the systems, methods, and devices may include a filter or membrane that may help to separate the tethered and untethered reporter molecules. These devices, systems, and techniques allow a user to rapidly process samples that may contain the target DNA, without needing to amplify the target sequences. These devices and methods may be used to assay a wide variety of samples and target DNA sources, for the presence or absence of target DNA sequences. Compositions and kits, useful in practicing these methods, for example detecting a target DNA in a biological sample, are also described.

Embodiments disclosed herein include devices, methods, and systems for direct, selective, and sensitive detection of single-stranded and double-stranded target DNA sequences from various sources using a Cas12a protein. When activated by binding a target DNA sequence, the Cas12a cleaves a tether releasing a reporter molecule that may then be detected. In some embodiments, the systems, methods, and devices may include a filter or membrane that may help to separate the tethered and untethered reporter molecules. These devices, systems, and techniques allow a user to rapidly process samples that may contain the target DNA, without needing to amplify the target sequences. These devices and methods may be used to assay a wide variety of samples and target DNA sources, for the presence or absence of target DNA sequences. Compositions and kits, useful in practicing these methods, for example detecting a target DNA in a biological sample, are also described.