DNA cascaded circuits have great potential in detecting low abundance molecules in complex biological environment due to their powerful signal amplification capability and nonenzymatic feature. However, the problem of the cascaded circuits is that the design is relatively complex and the kinetics is slow. Herein, a new design paradigm called catalyst-accelerated circular cascaded circuits is proposed, where the catalyst inlet is implanted and the reaction speed can be adjusted by the catalyst concentration. This new design is very simple and only requires three hairpin probes. Meanwhile, the results of a series of studies demonstrate that the reaction speed can be accelerated and the sensitivity can be also improved. Moreover, endogenous mRNA can also be used as a catalyst to drive the circuits to amplify the detection of target miRNA in live cells and in mice. These catalyst-accelerated circular cascaded circuits can substantially expand the toolbox for intracellular low abundance molecular detection.
Keywords: DNA circuits; cancer cells; fluorescence imaging; mRNA; miRNA.
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