High Sensitivity Detection of Tumor Cells in Biological Samples using Multivalent Aptamer Strand Displacement Strategy

Monitoring the cell surface-expressed nucleolin facilitates early cancer diagnosis. Herein, we developed multivalent aptamer displacement strand duplex strategy on the cell membranes utilizing a multi-receptor co-recognition design for improving sensitivity...

Constructing DNA logic circuits based on the toehold preemption mechanism

Preemptor blocks the strand displacement reaction by acting on DNA complex, not by directly hybridizing with the worker.

Mismatched fluorescent probes with enhanced strand displacement reaction rate for intracellular long noncoding RNA imaging

We design a mismatched fluorescent probe to directly monitor the long noncoding RNA (lncRNA) in living cells. The introduction of mismatched bases in the fluorescent probe greatly enhances the strand...

Toehold mediated strand displacement to measure released product from self-cleaving ribozymes

This paper presents a probe comprising a fluorophore and a quencher, enabling measurement of released product from self-cleaving hammerhead ribozyme, without labeled RNA molecules, regular sampling or use of polyacrylamide gels. The probe is made of two DNA strands; one strand is labelled with a fluorophore at its 5′-end, while the other strand is labelled with a quencher at its 3′-end. These two DNA strands are perfectly complementary, but with a 3′-overhang of the fluorophore strand. These unpaired nucleotides act as a toehold, which is utilized by a detached cleaved fragment (coming from a self-cleaving hammerhead ribozyme) as the starting point for a strand displacement reaction. This reaction causes the separation of the fluorophore strand from the quencher strand, culminating in fluorescence, detectable in a plate reader. Notably, the emitted fluorescence is proportional to the amount of detached cleaved-off RNAs, displacing the DNA quencher strand. This method can replace or complement radio-hazardous unstable 32P as a method of measurement of the product release from ribozyme cleavage reactions; it also eliminates the need for polyacrylamide gels, for the same purpose. Critically, this method allows to distinguish between the total amount of cleaved ribozymes and the amount of detached fragments, resulting from that cleavage reaction.