期刊
BIOSENSORS & BIOELECTRONICS
卷 144, 期 -, 页码 -出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2019.111692
关键词
DNA walker; Proximity ligation assay; Telomerase; Exponential amplified assay
类别
资金
- National Natural Science Foundation of China [21645009, 31527803, 21545010]
- Natural Science Foundation of Hunan Province [2018JJ2419]
- STS Program of the Chinese Academy of Sciences [KFJ-SW-STS-173]
A highly flexible electrochemical assay based on target-triggered DNAzyme spiders was proposed for the detection of telomerase. The DNAzyme-telomerase substrate primers (D-TSP) containing Cu2+-dependent DNAzymes serve as recognition elements, and primers of telomerase. Telomerase extracted from Hela cells recognize the D-TSP and elongated with DNA sequence repeats. A synthetic telomerase product hybridized with scaffold sequences of two DNAzyme-tethered probes on the basis of the mechanism of the proximity-ligation assay. The three-leg DNAzyme spiders has been assembled and initiated the autonomous hybridization/nicking/displacement cycles on substrate modified surface. The cleaved ferrocene-labeled fragements are adsorbed on gold surface leading to an increase in the electrochemical signal. As a result, the one input target, telomerase, release large amount of ferrocene-labeled DNA strands, achieving an exponential signal amplification and an excellent improvement in sensitivity over single molecule or two-component 'sandwich' binding complexes. Our proposed biosensor showed a nonlinear dependence with Hela cell numbers, ranging from 25 to 2000 with a detection limit of 10 cells. Telomerase activities from different cell lines were also successfully evaluated. Our electrochemical strategy based on target-triggered DNAzyme spiders was enzyme-free, PCR-free, simple in operation which indicated that it expected to expand the scope of DNA nanotechnology in the areas of clinical diagnosis.
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