文献类型：期刊文献

英文题名：A label-free electrochemical DNA sensor based on exonuclease III-aided target recycling strategy for sequence-specific detection of femtomolar DNA

作者：Wu, Di[1];Yin, Bin-Cheng[1];Ye, Bang-Ce[1]

机构：[1]E China Univ Sci & Technol, Lab Biosyst & Microanal, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2011

卷号：28

期号：1

起止页码：232

外文期刊名：BIOSENSORS & BIOELECTRONICS

收录：;EI(收录号：20113614310808);WOS:【SCI-EXPANDED(收录号:WOS:000295661700035)】；

基金：This work was financially supported by NSF (21075040), the Shanghai Project (09JC1404100, 11XD1401900), the SKLBE (2060204), and the Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：Electrochemical method; Exonuclease III; Signal amplification; DNA detection; Femtomolar

摘要：The present work demonstrates a rapid, single-step and ultrasensitive label-free and signal-off electrochemical sensor for specific DNA detection with excellent discrimination ability for single-nucleotide polymorphisms, taking advantage of Exonuclease III (Exo III)-aided target recycling strategy to achieve signal amplification. Exo III has a specifical exo-deoxyribonuclease activity for duplex DNAs in the direction from 3' to 5' terminus, however its activity on the duplex DNAs with 3'-overhang and single-strand DNA is limited. In response to the specific features of Exo III, the proposed E-DNA sensor is designed such that, in the presence of target DNA, the electrode self-assembled signaling probe hybridizes with the target DNA to form a duplex in the form of a 3'-blunt end at signaling probe and a 3'-overhang end at target DNA. In this way, Exo III specifically recognizes this structure and selectively digests the signaling probe. As a result, the target DNA dissociates from the duplex and recycles to hybridize with a new signaling probe, leading to the digestion of a large amount of signaling probes gradually. A redox mediator, Ru(NH(3))(6)(3+) (RuHex) is employed to electrostatically adsorbed onto signaling probes, which is directly related to the amount and the length of the signaling probes remaining in the electrode, and provides a quantitative measure of sequence-specific DNA with the experimentally measured (not extrapolated) detection limit as low as 20 fM. Moreover, this E-DNA sensor has an excellent differentiation ability for single mismatches with fairly good stability. (C) 2011 Elsevier B.v. All rights reserved.