Issue 23, 2019

Ag+-coordinated oligonucleotides on gold nanoparticles for anodic-stripping voltammetric immunoassay of cancer antigen 125 for cervical carcinoma

Abstract

A simple and enzyme-free electrochemical immunoassay was developed for the sensitive screening of cancer antigen 125 (CA 125; one biomarker for epithelial ovarian tumors and cervical carcinoma) using anodic-stripping voltammetry (ASV). The electrochemical immunosensor was constructed through immobilization of monoclonal anti-CA 125 antibody on an activated glassy carbon electrode on the basis of a classical carbodiimide coupling method. Cytosine (C)-rich oligonucleotide strands and polyclonal anti-CA 125 antibody labeled onto gold nanoparticles (AuNPs) were used as detection probes to quantify the target analyte with a sandwiched assay format. The voltammetric signal derived from the coordinated silver ions (Ag+) on the AuNPs through the C–Ag+–C coordination chemistry. Accompanying the formation of target-induced immunocomplexes, the coordinated Ag+ ions exhibited good voltammetric characteristics within the applied potentials. Under optimal conditions, the C–Ag+–C-based immunoassay displayed sensitive responses toward target CA 125 within a dynamic linear range of 0.01–100 U mL−1 at a limit of detection of 6.8 mU mL−1. Good reproducibility, high specificity and acceptable accuracy of this method were acquired for analysis of human serum specimens. Importantly, this immunoassay system offers a promising protocol for the detection of disease-related biomarkers without the need for natural enzymes.

Graphical abstract: Ag+-coordinated oligonucleotides on gold nanoparticles for anodic-stripping voltammetric immunoassay of cancer antigen 125 for cervical carcinoma

Article information

Article type
Paper
Submitted
25 Apr 2019
Accepted
15 May 2019
First published
15 May 2019

Anal. Methods, 2019,11, 2976-2982

Ag+-coordinated oligonucleotides on gold nanoparticles for anodic-stripping voltammetric immunoassay of cancer antigen 125 for cervical carcinoma

H. Xue, J. Zheng, Q. Chen, Q. Wang, Y. Lin and J. Chen, Anal. Methods, 2019, 11, 2976 DOI: 10.1039/C9AY00875F

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