BRCA1 gene ultrasensitive spectrophotometric detection on endonuclease assisted target circle and hybridization chain reaction

In this work, we demonstrated a ultrasensitive approach for DNA assay base on endonuclease assisted target circle and the hybridization chain reaction (HCR). The dual signal amplification process consists target DNA recognition, nicking enzyme triggered target circle, and hybridization chain reaction. In the presnece of target DNA, the hairpin probe DNA (HP1) was recoginized and partially hybridized with the target to form double-stranded strutures contianing the full recognition sequences for nicking endonuclease. Under the reaction of nicking endonuclease, HP1 was cleavaged into two fragments (trigger DNA and DNA S1) and the target DNA was dissociated from the DNA duplexes. The releasing DNA S1 was able to initiate another endonuclease assisted target circle with the assistance of hairpin probe DNA (HP2)