The present invention provides methods for signal amplification. The methods use DNA hybridization chain reaction to build labeled nanoscaffolds off of target analytes. The methods are reversible, as the detectable signal can be removed using DNA hybridization and hydrolysis.

The present invention provides methods for signal amplification. The methods use DNA hybridization chain reaction to build labeled nanoscaffolds off of target analytes. The methods are reversible, as the detectable signal can be removed using DNA hybridization and hydrolysis.

Described herein is a method for detecting an oligonucleotide in a sample, and in particular, to a method for detecting sense and antisense strands of an oligonucleotide duplex in a sample.

Described herein is a method for detecting an oligonucleotide in a sample, and in particular, to a method for detecting sense and antisense strands of an oligonucleotide duplex in a sample.

There is disclosed a kit for detecting a single strand target nucleotide sequence comprising: at least one first nucleic acid probe from 10 to 14 bases, to the 5′ end of which at least one fluorophore is bound; at least one second nucleic acid probe from 35 to 50 bases, comprising, from the 5′ to the 3′ end: a first segment having a nucleotide sequence complementary to the first nucleic acid probe, at least one quencher, and a second segment having a nucleotide sequence complementary to at least part of the target nucleotide sequence, wherein the following relation is met:
|ΔG hybr.target3−probe2|>|ΔG hybr.probe1−probe2|.

There is disclosed a kit for detecting a single strand target nucleotide sequence comprising: at least one first nucleic acid probe from 10 to 14 bases, to the 5′ end of which at least one fluorophore is bound; at least one second nucleic acid probe from 35 to 50 bases, comprising, from the 5′ to the 3′ end: a first segment having a nucleotide sequence complementary to the first nucleic acid probe, at least one quencher, and a second segment having a nucleotide sequence complementary to at least part of the target nucleotide sequence, wherein the following relation is met:
|ΔG hybr.target3−probe2|>|ΔG hybr.probe1−probe2|.

Ultraspecific, programmable nucleic acid sensors capable of detecting and preferentially amplifying target DNA molecules comprising a particular SNP or mutation are provided. In some cases, the ultraspecific programmable nucleic acid sensors are useful for detecting SNP-containing DNA molecules indicative of cancer such as cell-free DNA circulating in the blood or indicative of organ transplant rejection Also provided are methods for construction of such ultraspecific nucleic acid sensors and methods for preferential amplification of target DNA molecules containing a mutation of interest, as well as testing systems for early cancer screening and routine monitoring of circulating cancer DNA using liquid biological samples such as serum, plasma, or saliva.

Ultraspecific, programmable nucleic acid sensors capable of detecting and preferentially amplifying target DNA molecules comprising a particular SNP or mutation are provided. In some cases, the ultraspecific programmable nucleic acid sensors are useful for detecting SNP-containing DNA molecules indicative of cancer such as cell-free DNA circulating in the blood or indicative of organ transplant rejection Also provided are methods for construction of such ultraspecific nucleic acid sensors and methods for preferential amplification of target DNA molecules containing a mutation of interest, as well as testing systems for early cancer screening and routine monitoring of circulating cancer DNA using liquid biological samples such as serum, plasma, or saliva.

The invention provides compositions and methods for making closed nucleic acid structures in which one or both strands are continuous. The closed nucleic acid structures can be used as sequencing templates among other applications.

The invention provides compositions and methods for making closed nucleic acid structures in which one or both strands are continuous. The closed nucleic acid structures can be used as sequencing templates among other applications.