A Responsive “Nano String Light” for Highly Efficient mRNA Imaging in Living Cells via Accelerated DNA Cascade Reaction

Abstract

Nonenzymatic DNA catalytic amplification strategies have greatly benefited bioanalysis. However, long period incubation is usually required due to its relatively low reaction rate and efficiency, which limits its in vivo application. Here we design a responsive DNA nano string light (DNSL) by interval hybridization of modified hairpin DNA probe pairs to a DNA nanowire generated by rolling circle amplification and realize accelerated DNA cascade reaction (DCR) for fast and highly efficient mRNA imaging in living cells. Target mRNA initiates interval hybridization of two paired hairpin probes sequentially along the DNA nanowire and results in instant lighting up of the whole DNA nanowire with high signal gain due to the fast opening of all the self-quenched hairpins. The reaction time is about 6.7 times shorter compared with a regular DNA cascade reaction due to the acceleration based on domino effect. The cell delivery is achieved by modifying one of the hairpin probes with folic acid, and this intracellular imaging strategy is verified using human HeLa cells and intracellular survivin mRNA with a series of suppressed expressions as model, which provides a useful platform for fast and highly efficient detection of low-abundance nucleic acids in living cells.

The Growing Development of DNA Nanostructures for Potential Healthcare‐Related Applications

“…The aforementioned techniques involve a two‐step process during super resolution imaging, namely, first the docking and then the imaging steps. In work by Charlotte et al, a DNA nanowire was modified with folic acid and dye‐quencher pair‐labeled DNA hairpins for intracellular imaging of miRNA ( Figure ) . The DNA nanowire comprised two kinds of DNA hairpin probes arranged in a sequential chain with each labeled using a dye‐quencher pair.…”

“…In the OFF state, the fluorescence was quenched within the stem‐loop of the DNA hairpins, which opened in response to target cellular miRNA and created an amplified fluorescence signal. Reproduced with permission . Copyright 2018, American Chemical Society.…”

An intramolecular catalytic hairpin assembly on a DNA tetrahedron for mRNA imaging in living cells: improving reaction kinetics and signal stability

“…First, with traditional DDSA ampliers, reactions generally occur through random diffusion of dissociative probes in a bulk solution, which is difficult for collision of probes, and then leads to low efficiency and low kinetics of signal generation. [19][20][21] Second, dissociative DNA probes cannot independently enter cells. They are dependent on transfection or nanocarriers, [22][23][24] and the complex biological environment (especially the presence of nuclease) would degrade dissociative DNA probes and their reaction products, resulting in signal instability.…”

Nucleic‐Acid Structures as Intracellular Probes for Live Cells

“…In another recently reported DNA nanostructure system, Ren et al have developed an amplification strategy that overcomes limitations associated with HCR . In particular, the rate of HCR is reliant on diffusion as each successive hybridizing DNA sequence must be found in a complex 3D milieu.…”

“…In live cells, target amplification methods like PCR are challenging, and as such, signal amplification methods are the most common route to lowering the limit of detection. Techniques for signal amplification include hybridization chain reaction (HCR), hairpin DNA cascade amplifier (HDCA), and DNA chain reaction (DCR) …”