Sequence-specific detection of trace DNA via a junction-probe electrochemical sensor employed template-enhanced hybridization strategy

Cascaded strand displacement for non-enzymatic target recycling amplification and label-free electronic detection of microRNA from tumor cells

“…1, a couple of quasi-reversible, well-defined redox peaks of [Fe(CN) 6 ] 3À/4À with maximum current intensity can be observed (curve a) on the bare AuE due to the excellent electron-transfer kinetics of [Fe(CN) 6 ] 3À/4À to the electrode surface. After the formation of the self-assembled monolayer of the junction probes and MCH on the electrode surface, the peak current responses of [Fe(CN) 6 ] 3À/4À decrease dramatically (curve b vs. a) because of the electrostatic repulsion of the negatively charged [Fe(CN) 6 ] 3À/4À from approaching the electrode surface by the negatively charged phosphate backbones of the junction probes [28]. Subsequent incubation of the MCH/junction-probe/AuE with the target miRNA-21 and the FS leads to the recovery of the peak current responses (curve c), owing to the reduction of the surface negative charges induced by the disruption of the DNA junction structures by the two TSDR process.…”

RNA and DNA Diagnostics

“…Other DNA beacons were introduced with the concept of template-enhanced hybridization. Following this strategy, Zhang et al (2009b) demonstrated that a template (the target) provokes the formation of a ternary complex ("Y" junction structure) with two other partially complementary sequences (Fig. 3 Right).…”