Near-Infrared-Light-Mediated DNA-Logic Nanomachine for Bioorthogonal Cascade Imaging of Endogenous Interconnected MicroRNAs and Metal Ions.

The interconnection of microRNAs (miRNAs) and metal ions governs multiple biological processes in disease development and progression. However, developing multiplexed tools for dynamic imaging of these regulators remains a significant challenge. Herein, we report a conceptual approach for the design of an optically controlled DNA nanomachine by introducing a ternary DNAzyme-based, UV light-cleavable DNA scaffold and upconversion nanoparticle to the activatable hybrid chain reaction. We demonstrate that this nanomachine is capable of being effectively operated either in the presence of an endogenous miRNA target or the coexistence of intracellular Zn 2+ and external near-infrared light, resulting in enhanced fluorescence resonance energy transfer signals. With this design, the logic-gated imaging of endogenous miR-21 and Zn 2+ is demonstrated in living cells. More importantly, taking advantages of photoacoustic imaging modality, a combinational logic circuit (AND/OR) is constructed for the bioorthogonal cascade imaging of miR-21 and Zn 2+ in vivo , realizing dynamic monitoring of the correlation of miRNA and metal ions levels. Collectively, our results suggest that this conceptual design possesses the ability to expand the DNA nanomachine toolbox for visualizing a broad spectrum of interconnected molecules and thus provides new perspectives to improve the diagnostic and therapeutic outcomes.