In Situ Detection and Imaging of Telomerase Activity in Cancer Cell Lines via Disassembly of Plasmonic Core-Satellites Nanostructured Probe

The label-free localized surface plasmon resonance (LSPR) detection technique has been identified as a powerful means for in situ investigation of biological processes and localized chemical reactions at single particle level with high spatial and temporal resolution. Herein, a core-satellites assembled nanostructure of Au-50@Au-13, was designed for in situ detection and intracellular imaging of telomerase activity by Combining plasmonic resonance Rayleigh scattering spectros-copy with dark-field microscope (DFM). The Au-50@Au-13 was fabricated by using 50 nm gold nanoparticles (Au-50) as core and 13 nm gold nanoparticles (Au-13) as satellites, both of them were functionalized with single chain DNA and gathered, proximity through the highly specific DNA hybridization with a nicked hairpin DNA (O1) containing a telomerase substrate (TS) primer as linker. In the presence of telomerase, the telomeric repeated sequence of (TTAGGG) extended, at the 3 '-end of O1 would hybridized with its complementary sequences at 5 '-ends. This led the telomerase extension product of O1 be folded to form a rigid hairpin structure. As a result, the Au-50@Au-13 was disassembled With the releasing of O1 and Au-13-S from Au-50-L, which dramatically decreased the plasmon coupling effect. The remarkable LSPR spectral shift was observed accompanied by a detectable color change from orange to green with the increase of telomerase activity at single particle level with a detection limit of 1.3 X 10(-13) IU. The ability of Au-50@Au-13. for in situ imaging intracellular telomerase activity, distinguishing cancer cells from normal cells, in situ monitoring the variation of cellular telomerase activity after treated with drugs were also demonstrated.