Development of a Self-Activating Dandelion-Shaped DNA Nanodevice for Amplified Imaging of mRNA and Precise Gene Silencing.

Messenger RNAs (mRNAs) are a key regulatory factor of gene expression, and their dysregulated expression is closely associated with the occurrence and prognosis of various diseases. The sensitive monitoring of mRNAs in living cells is vital for clinical diagnosis and pathological research. Herein, we engineer a dandelion-shaped nanodevice for real-time imaging of TK1 mRNA and precise gene therapy. The dandelion-shaped nanodevice (DSN) is obtained by the self-assembly of cholesterol-conjugated DNA strands, which can load two functional components: a sensing module containing a functional hairpin probe for the amplified imaging of intracellular mRNA and a regulation module containing therapeutic small interfering RNAs (siRNAs) for achieving gene therapy. Notably, this DNA nanodevice not only facilitates the efficient delivery of probes and signal amplification but also exhibits superior kinetic behavior due to the spatial constraint effect. This DNA nanodevice facilitates a one-step and rapid (within 5 min) detection of TK1 mRNA with a detection limit of 57.57 fM. Moreover, this method can accurately quantify mRNAs at the single-cell level, measure the mRNA level in breast cancer tissues, monitor the dynamic changes of intracellular mRNA expression, and achieve tumor-specific gene silencing in vivo, holding great potential in clinical diagnosis and targeted gene therapy.