Sensitive competitive flow injection chemiluminescence immunoassay for IgG using gold nanoparticle as label

Area of Science:

• Analytical Chemistry
• Biochemistry
• Nanotechnology

Background:

• Immunoglobulin G (IgG) is a crucial biomarker in various clinical diagnostics.
• Developing sensitive and rapid immunoassays is essential for timely disease detection.
• Chemiluminescence immunoassays (CLIA) offer high sensitivity but can be time-consuming.

Purpose of the Study:

• To develop a sensitive competitive flow injection chemiluminescence immunoassay (CL-FIA) for immunoglobulin G (IgG).
• To utilize gold nanoparticles (AuNPs) as chemiluminescence labels for enhanced detection.
• To establish a rapid and efficient method for IgG quantification in clinical settings.

Main Methods:

• Immobilization of anti-IgG antibodies on a glass capillary column to create an immunoaffinity column.
• Competitive binding assay between analyte IgG and AuNP-labeled IgG for surface-confined antibodies.
• Chemiluminescence generation via luminol-hydrogen peroxide reaction catalyzed by Au (III) ions from dissolved AuNPs.
• Detection of IgG concentration based on the inverse relationship between bound AuNP-labeled IgG and CL intensity.

Main Results:

• The developed CL-FIA method demonstrated high sensitivity for IgG detection.
• Linearity of CL intensity with IgG concentration was observed from 1.0 ng mL⁻¹ to 40 ng mL⁻¹.
• A low detection limit of 5.2×10⁻¹⁰ gm L⁻¹ was achieved.
• The entire assay procedure, including washing steps, was completed in 30 minutes per sample.

Conclusions:

• The gold nanoparticle-labeled competitive CL-FIA is a promising method for sensitive and high-speed clinical assays.
• This approach offers advantages in terms of speed and sensitivity compared to existing CL immunoassays.
• The integration of nanoparticle labels and flow injection technology enhances immunoassay performance.