Robust Fuel Catalyzed DNA Molecular Machine for in Vivo MicroRNA Detection

Abstract

Monitoring microRNA (miRNA) expression, specifically those in vivo, is an effective option for evaluating tumor progression and providing real‐time information for future therapeutic efficacy. However, measuring miRNA in situ is still a big challenge owing to its short length and low intracellular abundance. In the present study, a DNA molecular machine powered with double‐stranded fuel (DSF) is constructed to profile miRNA in living cancer cells and tumor tissues. The sensing performance of DSF‐aided probes is optimized in vitro. After tumor cells are transfected with DSF‐containing probes, the pre‐existing intracellular miRNA can trigger the operation of cascaded circuit, accompanying with an amplified release of signal strands in living cells. Consequently, recognizable cellular images are obtained compared with that of the system without DSF. Moreover, the visualization of miRNA expression in tumor‐bearing mice with DNA catalytic circuit is explored for the first time. Importantly, with DSF‐aided probes, a more distinct signal in tumor tissues is exhibited compared to that of the traditional single‐stranded fuel method.