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Issue 21, 2018
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A novel electrochemical immunoassay for carcinoembryonic antigen based on glucose oxidase-encapsulated nanogold hollow spheres with a pH meter readout

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Abstract

A portable electrochemical immunosensing protocol was designed for the sensitive detection of a disease-related tumor biomarker (carcinoembryonic antigen, CEA, used in this case) on a pH meter using glucose oxidase (GOx)-encapsulated gold hollow microspheres (AuHMs) for signal amplification. The assay was carried out on a monoclonal anti-CEA capture antibody-coated microplate with a sandwich-type reaction mode. The GOx-entrapped AuHM was first synthesized 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 the pH value, which could be quantitatively determined on a portable pH meter. The use of gold hollow microspheres was expected to enhance the loaded amount of GOx for signal amplification. Two labeling protocols including GOx-labeled secondary antibody and GOx-AuHM-labeled secondary antibody were investigated for CEA detection, and improved analytical features were acquired with GOx-AuHM labeling. With the GOx-AuHM labeling strategy, the pH meter-based immunosensing device exhibited 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 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 the commercialized electrochemiluminescent method for CEA determination.

Graphical abstract: A novel electrochemical immunoassay for carcinoembryonic antigen based on glucose oxidase-encapsulated nanogold hollow spheres with a pH meter readout

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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, 2018,143, 5271-5277
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    A novel electrochemical immunoassay for carcinoembryonic antigen based on glucose oxidase-encapsulated nanogold hollow spheres with a pH meter readout

    Y. Jiang, Z. Su, J. Zhang, M. Cai and L. Wu, Analyst, 2018, 143, 5271
    DOI: 10.1039/C8AN01436A

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