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Published on: September 19, 2017
Flow-injection electrochemical immunosensor for the detection of human IgG based on glucose oxidase-derivated
Dianping Tang1, Reinhard Niessner, Dietmar Knopp
1Chair for Analytical Chemistry, Institute of Hydrochemistry, Technische Universität München, Marchioninistrasse 17, D-81377 München, Germany.
Insights
A novel electrochemical immunosensor effectively monitors Immunoglobulin G (IgG) in human serum. Using glucose oxidase (GOx) as a blocking agent significantly improves detection limits compared to bovine serum albumin (BSA).
Area of Science:
- Electrochemistry
- Biosensing
- Nanotechnology
Background:
- Immunoglobulin G (IgG) is a crucial biomarker in human serum for diagnosing various diseases.
- Existing methods for IgG detection often face limitations in sensitivity, selectivity, or complexity.
- Development of advanced biosensors is essential for accurate and efficient clinical diagnostics.
Purpose of the Study:
- To develop a novel flow-through electrochemical immunosensor for sensitive and selective detection of IgG in human serum.
- To investigate the efficacy of core-shell SiO(2)/Au nanocomposites and poly(amidoamine) G4 dendrimer as matrices.
- To compare the performance of glucose oxidase (GOx) as a blocking reagent against traditional bovine serum albumin (BSA).
Main Methods:
- Fabrication of a core-shell SiO(2)/Au nanocomposite and G4 dendrimer-modified electrode.
- Immobilization of ferrocenecarboaldehyde-labeled anti-IgG biomolecules.
- Utilizing glucose oxidase (GOx) as a blocking agent to enhance signal transduction via enzyme-catalyzed glucose oxidation.
- Electrochemical detection of IgG through the formation of an antibody-antigen complex and its effect on electron transfer.
Main Results:
- The developed immunosensor demonstrated a significantly lower detection limit (8.0 x 10(-7) mol/L) using GOx compared to BSA (1.5 x 10(-5) mol/L).
- The linear detection range for IgG was broader and more sensitive when employing GOx (5.0 x 10(-6) to 9.6 x 10(-4) mol/L).
- The immunosensor exhibited acceptable selectivity, reproducibility, and stability, with results consistent with clinical laboratory data for human serum samples.
Conclusions:
- The novel flow-through electrochemical immunosensor offers a highly sensitive and reliable method for IgG quantification in human serum.
- The use of GOx as a blocking reagent represents a significant advancement over BSA, enhancing sensor performance.
- This developed biosensor holds promise for practical clinical applications in disease diagnosis and monitoring.
Abstract:
A newly flow-through electrochemical immunosensor for monitoring IgG in human serum has been developed by using core-shell SiO(2)/Au nanocomposites and poly(amidoamine) G4 dendrimer as matrices. The ferrocenecarboaldehyde-labeled anti-IgG biomolecules were initially chemisorbed onto the nanoparticle surface, and then glucose oxidase (GOx), as a blocking reagent instead of bovine serum albumin (BSA), was backfilled onto the modified surface. The formation of the antibody-antigen complex by a simple one-step immunoreaction between the immobilized anti-IgG and IgG in sample solution introduced a barrier of direct electrical communication between the immobilized GOx and the base surface, and decreased the immobilized GOx toward the catalytic oxidation of glucose. The performance and factors influencing the performance of the immunosensor were evaluated. Under optimal conditions, the linear range of the developed immunosensor by using GOx as enhancer was from 5.0 x 10(-6) to 9.6 x 10(-4)mol/L with a detection limit of 8.0 x 10(-7)mol/L IgG (at 3delta), while the detection limit by using BSA was 1.5 x 10(-5)mol/L IgG (at 3delta) with the linear range from 3.5 x 10(-5) to 1.2 x 10(-3)mol/L. The selectivity, reproducibility and stability of the proposed immunosensor were acceptable. The IgG contents in 37 human serum samples obtained by the proposed method are identical with the data of clinical laboratory.
