2 research outputs found

    Switchable Fluorescent Imaging of Intracellular Telomerase Activity Using Telomerase-Responsive Mesoporous Silica Nanoparticle

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    This work designs a telomerase-responsive mesoporous silica nanoparticle (MSN) to realize in situ “off-on” imaging of intracellular telomerase activity. In the wrapping DNA (O1) sealed MSN probe, a black hole fluorescence quencher is covalently immobilized on the inner walls of the mesopores, while fluorescein is loaded in the mesopores. In the presence of telomerase and dNTPs, the designed O1 can be extended and then moves away from the MSN surface via forming a rigid hairpin-like DNA structure. Thus the O1 can act as a “biogate” to block and release fluorescein for “off-on” switchable fluorescent imaging. The MSN probe exhibits good performance for sensitive in situ tracking of telomerase activity in living cells. The practicality of this protocol has been verified by monitoring the change of cellular telomerase activity in response to telomerase-related drugs

    Smart Vesicle Kit for In Situ Monitoring of Intracellular Telomerase Activity Using a Telomerase-Responsive Probe

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    A smart vesicle kit was designed for in situ imaging and detection of cytoplasmic telomerase activity. The vesicle kit contained a telomerase primer (TSP) and a Cy5-tagged molecular beacon (MB) functionalized gold nanoparticle probe, which were encapsulated in liposome for intracellular delivery. After the vesicle kit was transfected into cytoplasm, the released TSP could be extended in the presence of telomerase to produce a telomeric repeated sequence at the 3′ end, which was just complementary with the loop of MB assembled on probe surface. Thus, the MB was opened upon hybridization to switch the fluorescent state from “off” to “on”. The fluorescence signal depended on telomerase activity, leading to a novel strategy for in situ imaging and quantitative detection of the cytoplasmic telomerase activity. The cytoplasmic telomerase activity was estimated to be 3.2 × 10<sup>–11</sup>, 2.4 × 10<sup>–11</sup>, and 8.6 × 10<sup>–13</sup> IU in each HeLa, BEL tumor and QSG normal cell, respectively, demonstrating the capability of this approach to distinguish tumor from normal cells. The proposed method could be employed for dynamic monitoring of the cytoplasmic telomerase activity in response to a telomerase-based drug, suggesting the potential application in discovery and screening of telomerase-targeted anticancer drugs
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