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Biosens Bioelectron. 2014 Dec 15;62:274-9. doi: 10.1016/j.bios.2014.06.056. Epub 2014 Jul 1.

A novel electrochemical biosensor for ultrasensitive and specific detection of DNA based on molecular beacon mediated circular strand displacement and rolling circle amplification.

Author information

1
The Center for Clinical Molecular Medical detection, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
2
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China.
3
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China. Electronic address: dingshijia@163.com.

Abstract

A novel electrochemical biosensing strategy was developed for ultrasensitive and specific detection of target DNA using a cascade signal amplification based on molecular beacon (MB) mediated circular strand displacement (CSD), rolling circle amplification (RCA), biotin-strepavidin system, and enzymatic amplification. The target DNA hybridized with the loop portion of MB probe immobilized on the gold electrode and triggered the CSD, leading to multiple biotin-tagged DNA duplex. Furthermore, via biotin-streptavidin interaction, the RCA was implemented, producing long massive tandem-repeat DNA sequences for binding numerous biotinylated detection probes. This enabled an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor showed very high sensitivity and selectivity with a dynamic response range from 1 fM to 100 pM. The proposed strategy could have the potential for applying in clinical molecular diagnostics and environmental monitoring.

KEYWORDS:

Alkaline phosphatase; Circular isothermal strand displacement amplification; Electrochemical DNA sensor; Rolling circle amplification

PMID:
25022510
DOI:
10.1016/j.bios.2014.06.056
[Indexed for MEDLINE]

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