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Published on: June 14, 2018
Conductometric immunoassay for interleukin-6 in human serum based on organic/inorganic hybrid membrane-functionalized
Ke-Zhong Liang1, Jun-Sheng Qi, Wei-Jun Mu
1Department of Chemistry and Environment, Chongqing Three Gorges University, 400400, Chongqing, People's Republic of China. liangkezhong@msn.com
Insights
A novel conductometric immunoassay using a hybrid membrane interface offers a simple and sensitive method for detecting interleukin-6 (IL6) in human serum. This advanced sensor shows promise for routine diagnostics and broader biosecurity applications.
Area of Science:
- Biomedical Engineering
- Biosensor Technology
- Analytical Chemistry
Background:
- Existing interleukin-6 (IL6) immunoassays often lack sensitivity and are not suitable for routine clinical use.
- There is a need for simple, sensitive, and reliable methods for IL6 detection in human serum.
Purpose of the Study:
- To develop a sensitive conductometric immunoassay for IL6 detection in human serum.
- To utilize an organic/inorganic hybrid membrane-functionalized interface for enhanced immunosensor performance.
Main Methods:
- Fabrication of a hybrid membrane using thionine-bound perylenetetracarboxylic acid, colloidal alumina, and nanogold particles.
- Immobilization of horseradish peroxidase-labeled anti-IL6 antibodies onto the nanogold surface.
- Conductometric detection based on changes in conductivity during antigen-antibody interactions in a specific buffer solution.
Main Results:
- The developed immunosensor demonstrated a wide linear detection range (25-400 pg/ml) for IL6.
- Achieved a low detection limit of 5 pg/ml (S/N = 3), indicating high sensitivity.
- The sensor showed acceptable stability, reproducibility, and precision, with results consistent with standard ELISA for serum samples.
Conclusions:
- The organic/inorganic hybrid membrane enhances biomolecule immobilization and immunosensor sensitivity.
- The proposed conductometric immunoassay is a promising, simple, and sensitive method for IL6 detection.
- This methodology holds potential for the detection of other proteins and for biosecurity applications.
Abstract:
Various sensor-based immunoassay methods have been extensively developed for the detection of interleukin-6 (IL6), but most often exhibit low detection signals and low detection sensitivity, and are unsuitable for routine use. The aim of this work is to develop a simple and sensitive conductometric immunoassay for IL6 in human serum by using an organic/inorganic hybrid membrane-functionalized interface. Initially, thionine-bound 3,4,9,10-perylenetetracarboxylic acid was doped into colloidal alumina, then nanogold particles were immobilized onto the thionine surface, and then horseradish peroxidase-labeled anti-IL6 antibodies were conjugated on the nanogold surface. The organic/inorganic hybrid membrane provides a good microenvironment for the immobilization of biomolecules, enhanced the surface coverage of protein, and improved the sensitivity of the immunosensor. The performance and factors influencing the performance of the immunosensor were evaluated. The detection is based on the change in local conductivity before and after the antigen-antibody interaction in 0.02 M phosphate buffer solution (pH 6.8) containing 50 microM H(2)O(2), 0.01 M KI and 0.15 M NaC1. Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 25 to 400 pg/ml towards IL6 with a relatively low detection limit of 5 pg/ml (S/N = 3). The stability, reproducibility and precision of the immunosensor were acceptable. 37 serum specimens were assayed by the developed immunosensor and standard enzyme-linked immunosorbent assay, respectively, and the results obtained were almost consistent. More importantly, the detection methodology provides a promising approach for other proteins or biosecurity.
