1 research outputs found
An Enzyme-Free DNA Circuit-Assisted Graphene Oxide Enhanced Fluorescence Anisotropy Assay for MicroRNA Detection with Improved Sensitivity and Selectivity
Graphene
oxide (GO) has been proven as an outstanding fluorescence
anisotropy (FA) amplifier. Yet the traditional GO amplified FA assays
lack high sensitivity because of the 1:1 binding ratio between target
and dye-modified probe. Herein, we report a new target-catalyzed hairpin
assembly (CHA), an enzyme-free DNA circuit, assisted GO amplified
FA strategy for microRNA-21 (miRNA-21) detection. In the presence
of miRNA-21, the CHA was initiated and plenty of H1–H2 duplexes
were produced continuously. The obtained H1–H2 duplex could
induce the formation of a H1–H2–probe DNA (pDNA) complex
by the toehold-mediated strand exchange reaction, which led the dye-modified
pDNA to leave away from the GO surface, resulting in a decreased FA
of the system. By monitoring the decrease of FA, miRNA-21 could be
detected in the range of 0–16 nM. The limit of detection (LOD,
3σ) was 47 pM, which was 194 times lower than that without CHA.
In addition, the selectivity of this method has also been enhanced
greatly as compared to that without CHA. Our method has great potential
to be applied for detecting different types of targets and monitoring
diverse molecular interactions by adapting the corresponding nucleotide
sequence