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Catalytic assembly of DNA nanostructures on nanoporous gold array as 3D architectures for label-free telomerase activity sensing

Abstract

Telomerase, an enzyme known to catalyze telomere elongation by adding TTAGGG [thymine (T), adenine (A), and guanine (G)] repeats to the end of telomeres, is vital for cell proliferation. Telomerase over-expression has been found in most tumor cells, resulting in telomere dysfunction and uncontrolled cellular proliferation. Thus, telomerase has been considered as a potential cancer biomarker, as well as a potential target in cancer therapy. In this study, telomerase-catalyzed growth of tandem G-quadruplex (G4) assembled on nanoporous gold array (NPGA) forms three-dimensional hybrid nano-architectures. The generated nanostructure would then capture malachite green (MG) (reporter molecule) without the need of a complicated labeling process. Upon laser irradiation, the captured MG molecules produce a surface-enhanced Raman scattering (SERS) signal that is generated by an abundant amount of plasmonic hot spots in the NPGA substrates. A limit of detection (LOD) of 10-10 IU along with a linear range that is 3 orders of magnitude has been achieved, which is equivalent to telomerase extracted from 20 HeLa cells. The LOD is 2 orders of magnitude better than the commercial enzyme-linked immunosorbent assay (ELISA), and it approaches the most sensitive technique, telomeric repeat amplification protocols (TRAP), which require labor and equipment-intensive polymerase chain reaction (PCR). In addition, x-ray photoelectron spectroscopy (XPS) was used to chemically identify and quantify telomerase activity on the sensitized NPGA surface. Furthermore, the sensor has been applied to screen the effectiveness of anti-telomerase drugs such as Zidovudine, thus demonstrating the sensor’s potential use in telomerase-based diagnosis and drug development. Moreover, the framework represents a novel paradigm of collaborative plasmonic intensification and catalytic multiplication (c-PI/CM) for label-free biosensing.

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Publication details

The article was received on 14 Mar 2017, accepted on 11 May 2017 and first published on 11 May 2017


Article type: Communication
DOI: 10.1039/C7NH00042A
Citation: Nanoscale Horiz., 2017, Accepted Manuscript
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    Catalytic assembly of DNA nanostructures on nanoporous gold array as 3D architectures for label-free telomerase activity sensing

    S. Qiu, F. Zhao, O. Zenasni, J. Li and W. Shih, Nanoscale Horiz., 2017, Accepted Manuscript , DOI: 10.1039/C7NH00042A

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