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Novel electrochemical immunoassay for carcinoembryonic antigen based on glucose oxidase-encapsulated nanogold hollow spheres with pH meter readout

Abstract

A portable electrochemical immunosensing protocol was designed for the sensitive detection of disease-related tumor biomarker (carcinoembryonic antigen, CEA, used in this case) on a pH meter by using glucose oxidase (GOx)-encapsulated gold hollow microsphere (AuHM) for the signal amplification. The assay was carried out on monoclonal anti-CEA capture antibody-coated microplate with a sandwich-type reaction mode. GOx-entrapped AuHM was first synthesized by using the reverse micelle method, and then used as the signal-generation tag for the labeling of polyclonal anti-CEA detection antibody. Accompanying the formation of the sandwiched immunocomplexes, the loaded GOx molecules in the microsphere could catalyze glucose into gluconic acid and hydrogen peroxide. The as-produced gluconic acid changed the microenvironment of the detection solution, thus resulting in the shift of pH value, which could be quantitativey determined on a portable pH meter. Use of gold hollow microspheres was expected to enhance the loaded amount of GOx for the signal amplification. Two labeling protocols including GOx-labeled secondary antibody and GOx-AuHM-labeled secondary antibody were investigated for the CEA detection, and improved analytical features were acquired with GOx-AuHM labeling. With the GOx-AuHM labeling strategy, pH meter-based immunosensing device exhibied a good analytical performance for CEA detection within the dynamic linear range of 0.1 – 100 ng mL-1 at a detection limit of 0.062 ng mL-1. The strong attachment of anti-CEA antibodies to the GOx-AuHM brought a good repeatability and intermediate precision down to 10%. Importantly, no significant differences at the 0.05 significance level were encountered in the analysis of 12 human serum specimens between the developed immunoassay and commericallized electrochemiluminescent method for the CEA determination.

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Publication details

The article was received on 29 Jul 2018, accepted on 10 Sep 2018 and first published on 13 Sep 2018


Article type: Paper
DOI: 10.1039/C8AN01436A
Citation: Analyst, 2018, Accepted Manuscript
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    Novel electrochemical immunoassay for carcinoembryonic antigen based on glucose oxidase-encapsulated nanogold hollow spheres with pH meter readout

    Y. Jiang, Z. Su, J. Zhang, M. Cai and L. Wu, Analyst, 2018, Accepted Manuscript , DOI: 10.1039/C8AN01436A

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