期刊
BIOSENSORS & BIOELECTRONICS
卷 35, 期 1, 页码 230-234出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2012.02.054
关键词
Immobilization-free; Electrochemical; DNA sensor; Strand displacement
类别
资金
- Research Grants Council of the Hong Kong SAR Government (RGC) [601509]
- SRFI Initiative of the university [SRFI11EG01]
A highly sensitive electrochemical DNA sensor that requires no probe immobilization has been developed based on a target recycling mechanism utilizing a DNA polymerase with a strand displacement activity. The electrochemical detection is realized by taking advantage of the difference in diffusivity between a free ferrocene-labeled peptide nucleic acid (Fc-PNA) and a Fc-PNA hybridized with a complementary DNA, while the DNA polymerase-assisted target recycling leads to signal generation and amplification. The hybridization of the target DNA opens up a stem-loop template DNA with the Fc-PNA hybridized to its extruded 5' end and allows a DNA primer to anneal and be extended by the DNA polymerase, which results in sequential displacement of the target DNA and the Fc-PNA from the template DNA. The displaced target DNA will hybridize with another template DNA, triggering another round of primer extension and strand displacement. The released Fc-PNA, due to its neutral backbone, has much higher diffusivity towards a negatively charged electrode, compared to that when it is hybridized with a negatively charged DNA. Therefore, a significantly enhanced signal of Fc can be observed. The outstanding sensitivity and simplicity make this approach a promising candidate for next-generation electrochemical DNA sensing technologies. (C) 2012 Elsevier B.V. All rights reserved.
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