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Multiplexed electrochemical immunoassay for two immunoglobulin proteins based on Cd and Cu nanocrystals

Abstract

A simple and feasible electrochemical immunosensing method for simultaneous voltammetric detection of two immunoglobulin proteins including human IgG (HIgG) and rabbit IgG (RIgG) was developed by using two distinguishable signal-generation tags on the same electrode. The immunosensor was prepared by immobilizing two Fab antibody fragments on a gold electrode. Thereafter, Cu and Cd nanocrystals as the nanotags were synthesized and functionalized with identical detection antibodies. Transmission electron microscope (TEM) and fourier transform infrared spectroscope (FTIR) were employed to characterize the Cu and Cd nanocrystals. The covalently modified electrode with Fab antibody fragments through the Au-thiolate bond (to dispel the non-specific adsorption) was represented via scanning electron microscopy (SEM). After the sandwiched immunoreaction, the antibody-modified nanocrystals were captured on the immunosensor, which could be interrogated in pH 3.5 HCl by using square-wave anodic stripping voltammetry. Experimental results also indicated that the multiplexed immunoassay enabled the simultaneous detection of HIgG and RIgG in a single run with the similar linear range from 0.01 to 10 ng mL-1, and the limits of detection (LODs) toward two analytes could be down to 3.4 pg mL-1 (at 3σ). The acceptable assayed results on precision, reproducibility, specificity and method accuracy were also acquired. Importantly, the newly designed strategy avoided the cross-talk and the enzymatic introduction relative to conventional electrochemical immunoassays, thus providing a promising potential in clinical applications.

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Publication details

The article was received on 04 Sep 2017, accepted on 08 Nov 2017 and first published on 08 Nov 2017


Article type: Paper
DOI: 10.1039/C7AN01459G
Citation: Analyst, 2017, Accepted Manuscript
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    Multiplexed electrochemical immunoassay for two immunoglobulin proteins based on Cd and Cu nanocrystals

    D. Tang, J. Ren and M. Lu, Analyst, 2017, Accepted Manuscript , DOI: 10.1039/C7AN01459G

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