Journal
BIOSENSORS & BIOELECTRONICS
Volume 28, Issue 1, Pages 232-238Publisher
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2011.07.029
Keywords
Electrochemical method; Exonuclease III; Signal amplification; DNA detection; Femtomolar
Categories
Funding
- NSF [21075040]
- Shanghai Project [09JC1404100, 11XD1401900]
- SKLBE [2060204]
- Fundamental Research Funds for the Central Universities
Ask authors/readers for more resources
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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available