A NIR Light Gated DNA Nanodevice for Spatiotemporally Controlled Imaging of MicroRNA in Cells and Animals.

Nanodevices have potential as intelligent sensing systems for detection of microRNAs (miRNAs) in living cells. However, the resolution offered by "always active" nanodevices is often insufficient to manipulate miRNA sensing with high spatiotemporal control. In this work, using DNA nanotechnology we constructed an activatable DNA nanodevice programmed to detect miRNAs in vitro and in vivo with the high spatial and temporal precision of NIR light. Our nanodevice is functionalized on the surface of upconversion nanoparticles (UCNPs) with a rationally designed DNA beacon that displays UV light-activatable miRNA sensing activity. The UCNPs absorb deep-tissue-penetrable NIR light and emit high-energy UV light locally, which serve as transducers to operate the nanodevice in the NIR window. The nanodevice can naturally enter cells and enable remote regulation of its fluorescent imaging activity for miRNAs in living cells by NIR light illumination in a chosen place and time. Furthermore, we demonstrate that the nanodevice can be expanded to activatable imaging of intratumoral miRNAs in living mice. This work illustrates the potential of DNA nanodevices for miRNA detection with high spatiotemporal resolution, which could expand the toolbox of technologies for precise biological and medical analysis.