Colorimetric detection of microRNA based on DNAzyme and nuclease-assisted catalytic hairpin assembly signal amplification

Publication date: April 2018Source: Molecular and Cellular Probes, Volume 38Author(s): Hongmei Zhang, Kuiyu Wang, Shengjun Bu, Zhongyi Li, Chuanjing Ju, Jiayu WanAbstractAccurate and quantitative analysis of microRNA (miRNA) expression is critical for the diagnostics and theranostics of a disease. Herein, a proof-of-concept of a colorimetric horseradish peroxidase-mimicking DNAzyme (HRP-DNAzyme) biosensor for miRNA assay based on nuclease-assisted catalytic hairpin assembly (CHA) signal amplification was demonstrated. Duplex-specific nuclease (DSN) was employed to cleave the single-stranded DNA (ssDNA) chimeric probe (CP) on the magnetic bead (MB) surface via hybridization of the CP and target miRNA. The regenerated miRNA can cleave a large number of ssDNA CP to produce CHA initiator sequence fragments. The CP consists of two main regions: a target miRNA recognition DNA sequence at the 5′ end and a CHA initiator (CI) sequence at the 3′ end. The catalyzed assembly process of CHA produces a large amount of G-rich DNA. In the presence of hemin, the G-rich DNA forms G-quadruplex/hemin complex and mimics the horseradish peroxidase activity, which catalyzes a colorimetric reaction. For the proof-of-concept, microRNA-21 (miR-21) was selected as the model target to authenticate this strategy as a versatile assay platform. The proposed strategy allowed quantitation of the sequence specificity of miRNA-21 with a detection limit of 9.2 fM in a dynamic range from 10 fM–1 nM, with...

Source: Molecular and Cellular Probes - July 5, 2018 Category: Molecular Biology Source Type: research