A Smart Deoxyribozyme‐Programmable Catalytic DNA Circuit for High‐Contrast MicroRNA Imaging.

Synthetic catalytic DNA circuits have been recognized as a promising signal amplification toolbox for sensitive intracellular imaging, yet their selectivity and efficiency are always constrained by uncontrolled off‐site signal leakage and inefficient on‐site circuitry activation. Thus, the endogenously controllable on‐site exposure/activation of DNA circuits is highly desirable for achieving the selective imaging of live cells. Herein, an endogenously activated DNAzyme strategy was facilely integrated with a catalytic DNA circuit for guiding the selective and efficient microRNA imaging in vivo. To prevent the off‐site activation, the circuitry constitute was initially caged without sensing functions, which could be selectively liberated by DNAzyme amplifier to guarantee the high‐contrast microRNA imaging in target cells. This intelligent on‐site modulation strategy can tremendously expand these molecularly engineered circuits in biological systems. [ABSTRACT FROM AUTHOR]