Novel Single-Enzyme-Assisted Dual Recycle Amplification Strategy for Sensitive Photoelectrochemical MicroRNA Assay.

Herein, a novel single-enzyme-assisted dual recycle amplification strategy based on T7 exonuclease (T7 Exo) and a strand-displacement reaction (SDR) was designed to fabricate a photoelectrochemical (PEC) biosensor for sensitive microRNA-141 (miRNA-141) detection with the use of laminar bismuth tungstate (BiWO) as photoactive material. Compared with a traditional enzyme-assisted dual recycle amplification strategy, the presented method could effectively refrain the enzyme interference reaction, reduce environmental sensitivity, and save cost. Here, hairpin DNA1 (H1) decorated on magnetic beads (MB) hybridized with target miRNA-141 to form an H1/miRNA-141 heteroduplex.

A novel "signal on" photoelectrochemical strategy based on dual functional hemin for microRNA assay.

In this work, a novel "signal on" photoelectrochemistry (PEC) biosensor was constructed with dual-functional hemin as a signal quencher and electronic mediator for ultrasensitive target microRNA-141 assay with the assistance of T7 exonuclease (Exo)-initiated target amplification technology.

[Ru(dcbpy) dppz] /Fullerene Cosensitized PTB7-Th for Ultrasensitive Photoelectrochemical MicroRNA Assay.

A new cosensitization photoelectrochemical (PEC) strategy was established by using a donor-acceptor-type photoactive material, poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7-Th), as a signal indicator, which was cosensitized with bis(4,4'dicarboxyl-2,2'-bipyridyl)(4,5,9,14-tetraazabenzo[b]triphenylene)ruthenium(II) ([Ru(dcbpy) dppz] ) embedded in the grooves of the DNA duplex and fullerene (nano-C ) immobilized on the surface of DNA nanoflowers for microRNA assay. [Ru(dcbpy) dppz] and nano-C could effectively enhance the photoelectric conversion efficiency (PCE) of PTB7-Th as a result of well-matched energy levels among nano-C , [Ru(dcbpy) dppz] and PTB7-Th, leading to a clearly enhanced photocurrent signal. Meanwhile, a target recycling magnification technique based on duplex-specific nuclease was applied in this work to obtain higher detection sensitivity.