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Anal Chim Acta. 2014 Oct 27;848:67-73. doi: 10.1016/j.aca.2014.07.033. Epub 2014 Jul 24.

Ultrasensitive determination of DNA sequences by flow injection chemiluminescence using silver ions as labels.

Author information

1
Key Laboratory of Bioelectrochemistry & Enviromental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, No. 967 Anning East Road, Lanzhou, Gansu 730070, China.
2
Key Laboratory of Bioelectrochemistry & Enviromental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, No. 967 Anning East Road, Lanzhou, Gansu 730070, China. Electronic address: liuxh@nwnu.edu.cn.
3
Key Laboratory of Bioelectrochemistry & Enviromental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, No. 967 Anning East Road, Lanzhou, Gansu 730070, China. Electronic address: luxq@nwnu.edu.cn.

Abstract

We presented a new strategy for ultrasensitive detection of DNA sequences based on the novel detection probe which was labeled with Ag(+) using metallothionein (MT) as a bridge. The assay relied on a sandwich-type DNA hybridization in which the DNA targets were first hybridized to the captured oligonucleotide probes immobilized on Fe3O4@Au composite magnetic nanoparticles (MNPs), and then the Ag(+)-modified detection probes were used to monitor the presence of the specific DNA targets. After being anchored on the hybrids, Ag(+) was released down through acidic treatment and sensitively determined by a coupling flow injection-chemiluminescent reaction system (Ag(+)-Mn(2+)-K2S2O8-H3PO4-luminol) (FI-CL). The experiment results showed that the CL intensities increased linearly with the concentrations of DNA targets in the range from 10 to 500 pmol L(-1) with a detection limit of 3.3 pmol L(-1). The high sensitivity in this work may be ascribed to the high molar ratio of Ag(+)-MT, the sensitive determination of Ag(+) by the coupling FI-CL reaction system and the perfect magnetic separation based on Fe3O4@Au composite MNPs. Moreover, the proposed strategy exhibited excellent selectivity against the mismatched DNA sequences and could be applied to real samples analysis.

KEYWORDS:

Flow injection–chemiluminescent detection; Magnetic nanoparticles; Metallothioneins; Nucleic acid biosensors; Silver ions

PMID:
25263118
DOI:
10.1016/j.aca.2014.07.033
[Indexed for MEDLINE]

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