title: Ultrasensitive determination of DNA sequences by flow injection chemiluminescence using silver ions as labels.
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.
authors.affiliation: 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.
authors.forename: Lichun
authors.initials: L
authors.lastname: Zheng
authors.affiliation: 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.
authors.forename: Xiuhui
authors.initials: X
authors.lastname: Liu
authors.affiliation: 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.
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
authors.affiliation: 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.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Ma
authors.affiliation: 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.
authors.forename: Guofan
authors.initials: G
authors.lastname: Wu
authors.affiliation: 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.
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Lu
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008163:Luminescent Measurements; D008165:Luminol / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes / Q000737:chemistry; D017422:Sequence Analysis, DNA / Q000379:methods*; D012834:Silver / Q000737:chemistry*
chemical_list: D007477:Ions; D058185:Magnetite Nanoparticles; D015345:Oligonucleotide Probes; D012834:Silver; D008165:Luminol; D006046:Gold; D004247:DNA; D052203:Ferrosoferric Oxide
keywords: Flow injection–chemiluminescent detection; Magnetic nanoparticles; Metallothioneins; Nucleic acid biosensors; Silver ions