Functional Self-Assembled DNA Nanohydrogels for Specific Telomerase Activity Imaging and Telomerase-Activated Antitumor Gene Therapy.

Engineering a functional nanoplatform that integrates dynamic monitoring of endogenous biomarkers and a stimuli-activated therapeutic mode is promising for early diagnosis and treatment of cancers. In this study, we developed an intelligent DNA nanohydrogel with specific targeting capability that can be stimuli-activated for both in vitro telomerase detection and in vivo telomerase-triggered gene therapy. The DNA nanohydrogel was formed simply by the self-assembly of two Y-shaped DNA units and a double-stranded DNA linker labeled with fluorophores and loaded with therapeutic siRNA. When intracellular telomerase was overexpressed, the DNA nanohydrogel collapsed owing to the prolongation of the telomeric primer at the terminal sequence of one of the Y-shaped DNA units. As a result, the quenched fluorescence due to fluorescence resonance energy transfer (FRET) of the DNA nanohydrogel recovered and the trapped siRNA was released, enabling the accurate detection and imaging of intracellular telomerase activity as well as effective gene therapy of tumors. Benefiting from the great biocompatibility, specificity, and stimuli-responsive property, the developed DNA nanoplatform provides a new opportunity for precise cancer diagnosis and treatment as well as other biological applications.