期刊
ANALYTICAL CHEMISTRY
卷 91, 期 5, 页码 3619-3627出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.analchem.8b05610
关键词
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资金
- National Natural Science Foundation of China [21603099, 31772053, 21175097]
- International Cooperation Foundation from the Ministry of Science and Technology [2016YFE0130100]
- Priority Academic Program Development of Jiangsu Higher Education Institutions [YX10900212]
Human telomerase RNA (hTR), an important biomarker for cancer diagnosis, is the template for the synthesis of telomeric DNA repeats and is found to be 7-fold overexpressed in tumor cells. Herein, we present a photoelectrochemical (PEC) biosensor for hTR detection coupled with a novel amplification strategy based on cascades of catalytic hairpin assembly (CHA) and hyperbranched hybridization chain reaction (HB-HCR). At the electrode surface, thiolated hairpin 1 probes were immobilized on deposited CdS nanoparticles via a Cd-S bond. In the presence of target hTR, a CHA reaction was triggered and the exposing of triggerl could further initiate an HB-HCR reaction to form abundant hemin/G-quadruplex DNAzymes containing dendritic DNA structure. The DNAzymes' catalytic precipitation of 4-chloro-1-naphthol (4-CN) by H2O2 subsequently took place on the surface of the PEC electrode and efficiently suppressed the photocurrent output. Therefore, the change of photocurrent response had a positive linear relationship with logarithmic value of hTR concentration varying from 200 fM to 20.0 nM with a limit of detection (LOD) of 17.0 fM. The LOD for CHA/HB-HCR was about 8.8-fold lower than that of CHA/linear-branched HCR (CHA/LB-HCR) and 547-fold lower than that of CHA. By coupling the feature of high signal amplification capacity for DNA nanotechnology, a prominently stable, reproducible, and selective PEC biosensor was successfully constructed and applied in hTR detection.
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