期刊
BIOSENSORS & BIOELECTRONICS
卷 68, 期 -, 页码 487-493出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2015.01.043
关键词
Impedimetric immunosensor; Biocatalytic precipitation; Immuno-HCR assay; DNAzyme concatamer; Carcinoembryonic antigen
类别
资金
- National Natural Science Foundation of China [41176079, 21475025, 21305029]
- National Science Foundation of Fujian Province [2014J07001]
- Program for Changjiang Scholars and Innovative Research Team in University [IRT1116]
A novel signal-amplified impedimetric immunosensing strategy was successfully developed for ultrasensitive detection of low-abundance proteins (carcinoembryonic antigen, CEA, used as a model) based on hybridization chain reaction (HCR)-stimulated formation of DNAzyme concatamers on nanogold particle accompanying enzyme-triggered biocatalytic precipitation. The assay was carried out on capture antibody-modified electrode by using gold nanoparticle heavily functionalized with initiator strand and detection antibody as the signal-transduction tag with a sandwich-type immunosensing format. In the presence of target CEA, the formed immunocomplex underwent an unbiased strand-displacement reaction by the initiator strand on the gold nanoparticle between two auxiliary single-stranded DNA with the hemin aptamer. Upon hemin introduction, numerous DNAzyme molecules were formed on the concatamers and nanogold particle, which could catalyze 4-chloro-1-naphthol to produce an insoluble precipitation on the electrode, thereby resulting in the amplification of impedimetric signal. Under the optimal conditions, the immuno-HCR assay exhibited good impedimetric responses for the detection of target CEA in the working range from 1.0 pg mL(-1) to 20 ng mL(-1) with a detection limit of 0.42 pg mL(-1). In addition, the immuno-HCR assay was validated by measuring six human serum specimens for target CEA, receiving a highly matched correction between the obtained results by the immuno-HCR assay and the commercialized ELC-based immunoassay method. (C) 2015 Elsevier B.V. All rights reserved.
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