title: HCR-stimulated formation of DNAzyme concatamers on gold nanoparticle for ultrasensitive impedimetric immunoassay.
abstract: 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.
authors: Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University, Fuzhou 350116, PR China.
authors: Li
authors: L
authors: Hou
authors: Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University, Fuzhou 350116, PR China. Electronic address: wapple@fzu.edu.cn.
authors: Xiaoping
authors: X
authors: Wu
authors: Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University, Fuzhou 350116, PR China.
authors: Guonan
authors: G
authors: Chen
authors: Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University, Fuzhou 350116, PR China.
authors: Huanghao
authors: H
authors: Yang
authors: Institute of Environmental and Analytical Science, School of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, Henan, PR China. Electronic address: minghua.lu2009@hotmail.com.
authors: Minghua
authors: M
authors: Lu
authors: Institute of Nanomedicine and Nanobiosensing, Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University, Fuzhou 350116, PR China. Electronic address: dianping.tang@fzu.edu.cn.
authors: Dianping
authors: D
authors: Tang
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques; D002272:Carcinoembryonic Antigen / Q000097:blood / Q000302:isolation & purification*; D021881:DNA, Catalytic / Q000737:chemistry; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D009693:Nucleic Acid Hybridization
chemical_list: D055910:Antibodies, Immobilized; D002272:Carcinoembryonic Antigen; D021881:DNA, Catalytic; D006046:Gold
keywords: Biocatalytic precipitation; Carcinoembryonic antigen; DNAzyme concatamer; Immuno-HCR assay; Impedimetric immunosensor