2 research outputs found
Switchable Fluorescent Imaging of Intracellular Telomerase Activity Using Telomerase-Responsive Mesoporous Silica Nanoparticle
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
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