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Published on: November 13, 2017
Multiplexed electrochemical immunoassay for two immunoglobulin proteins based on Cd and Cu nanocrystals
Dianping Tang1, Jingjing Ren, Minghua Lu
1Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing 402160, PR China. dianping.tang@fzu.edu.cn.
Insights
A novel electrochemical immunosensing method enables simultaneous detection of human IgG (HIgG) and rabbit IgG (RIgG) using distinct nanotags on a single electrode. This sensitive assay shows promise for clinical applications.
Area of Science:
- Electrochemistry
- Biosensing
- Nanotechnology
Background:
- Simultaneous detection of multiple biomarkers is crucial for accurate disease diagnosis.
- Conventional electrochemical immunoassays often face challenges with cross-talk and enzymatic complexity.
Purpose of the Study:
- To develop a simple and feasible electrochemical immunosensing method for simultaneous detection of human IgG (HIgG) and rabbit IgG (RIgG).
- To utilize distinguishable signal-generation tags on a single electrode for multiplexed analysis.
Main Methods:
- Fabrication of a gold electrode modified with Fab antibody fragments.
- Synthesis and functionalization of copper (Cu) and cadmium (Cd) nanocrystals as nanotags.
- Square-wave anodic stripping voltammetry for signal detection after a sandwiched immunoreaction.
Main Results:
- Simultaneous detection of HIgG and RIgG in a single run with a linear range of 0.01–10 ng mL⁻¹.
- Achieved low limits of detection (LODs) as low as 3.4 pg mL⁻¹ for both analytes.
- Demonstrated good precision, reproducibility, specificity, and accuracy.
Conclusions:
- The developed electrochemical immunosensor effectively enables simultaneous detection of HIgG and RIgG.
- The strategy avoids cross-talk and enzymatic steps, offering a promising alternative for clinical applications.
- This method highlights the potential of nanotag-based electrochemical immunosensing for multiplexed biomarker analysis.
Abstract:
Herein, a simple and feasible electrochemical immunosensing method for simultaneous voltammetric detection of two immunoglobulin proteins, human IgG (HIgG) and rabbit IgG (RIgG), was developed using two distinguishable signal-generation tags on the same electrode. The immunosensor was prepared by immobilizing two Fab antibody fragments on a gold electrode. After this, Cu and Cd nanocrystals, as nanotags, were synthesized and functionalized with identical detection antibodies. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the Cu and Cd nanocrystals. The covalently modified electrode with the Fab antibody fragments through the Au-thiolate bond (to dispel the non-specific adsorption) was investigated 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 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) towards two analytes could be as low as 3.4 pg mL-1 (at 3σ). Acceptable assay results on precision, reproducibility, specificity, and method accuracy were also acquired. Importantly, the newly designed strategy avoided cross-talk and enzymatic introduction as compared to conventional electrochemical immunoassays, thus exhibiting a promising potential in clinical applications.
