2 research outputs found

    Photocaged Nanoparticle Sensor for Sensitive MicroRNA Imaging in Living Cancer Cells with Temporal Control

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    Sensitive imaging of microRNA in living cells is of great value for disease diagnostics and prognostics. While signal amplification-based strategies have been developed for imaging low-abundance disease-relevant microRNA molecules, precise temporal control over sensor activity in living cells still remains a challenge, and limits their applications for sensing microRNA concentration dynamics. Herein, we report a class of photocaged nanoparticle sensors for highly sensitive imaging of microRNA in living cells with temporal control. The sensor features a DNA-templated gold nanoparticle-quantum dot satellite nanostructure which is temporarily inactivated by a photocaged DNA mask. Upon UV light irradiation, the sensor restores its activity for catalytic sensing of microRNA in living cells via entropy-driven two-step toehold-mediated strand displacement reactions. We show that the sensor exhibits quick response to UV light, robust intracellular stability, and high specificity and sensitivity for the microRNA target. On the basis of this strategy, precise control over sensor activity is achieved using an external light trigger, where on-demand sensing could be potentially performed with spatiotemporal control

    MicroRNA-Catalyzed Cancer Therapeutics Based on DNA-Programmed Nanoparticle Complex

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    The use of cancer-relevant microRNA molecules as endogenous drug release stimuli is promising for personalized cancer treatment yet remains a great challenge because of their low abundance. Herein, we report a new type of microRNA-catalyzed drug release system based on DNA-programmed gold nanoparticle (GNP)–quantum dot (QD) complex. We show that a trace amount of miRNA-21 molecules could specifically catalyze the disassembly of doxorubicin (Dox)-loaded GNP–QDs complex through entropy driven process, during which the Dox-intercalating sites are destructed for drug release. This catalytic reaction could proceed both in fixed cells and live cells with miRNA-21 overexpression. Dox molecules could be efficiently released in the cells and translocate to cell nuclei. QD photoluminescence is simultaneously activated during catalytic disassembly process, thus providing a reliable feedback for microRNA-triggered drug release. The GNP–QDs–Dox complex exhibits much higher drug potency than free Dox molecules, and therefore represents a promising platform for accurate and effective cancer cell treatment