A DNA nanowire based localized catalytic hairpin assembly reaction for microRNA imaging in live cells

Here, we have developed a localized catalytic hairpin assembly (LCHA) strategy for intracellular miR-21 imaging by using DNA nanowires confining both hairpin probes in a compact space. The LCHA is constructed by interval hybridization of DNA hairpin probe pairs to a DNA nanowire with multiplex footholds generated by alternating chain hybridization. Compared to the conventional catalytic hairpin assembly (CHA) strategy, the LCHA significantly shortens the reaction time and enhances the sensitivity. Moreover, the proposed LCHA can serve as a carrier for delivery of probes into live cells as well as protect the probes from nuclease degradation and enhances the stability. We anticipate that this design can be widely applied in facilitating basic biomedical research and disease diagnosis.