Ultrasensitive electrochemiluminescence immunosensor based on luminol functionalized gold nanoparticle labeling

Area of Science:

• Analytical Chemistry
• Biotechnology
• Nanotechnology

Background:

• Development of ultrasensitive detection methods for biomarkers like human immunoglobulin G (hIgG) is crucial for diagnostics.
• Existing chemiluminescence immunoassay methods often face limitations in sensitivity, stability, and complexity.

Purpose of the Study:

• To develop an ultrasensitive electrochemiluminescence (ECL) immunosensor for detecting hIgG.
• To leverage luminol-functionalized gold nanoparticle (AuNP) labeling for signal amplification.
• To establish a simple, stable, and time-saving method for hIgG detection.

Main Methods:

• Fabrication of a sandwich-type immunocomplex on a streptavidin-coated AuNP modified electrode.
• Immobilization of biotin-conjugated goat-anti-human IgG primary antibody.
• Conjugation of hIgG antigen and luminol-functionalized AuNP-labeled secondary antibody.
• ECL measurement using a double-step potential in a carbonate buffer with H(2)O(2).

Main Results:

• The developed ECL immunosensor achieved an ultrasensitive detection limit of 1.0 pg/mL for hIgG (S/N=3).
• The method demonstrated superior sensitivity compared to previously reported techniques for hIgG determination.
• The assay proved to be simple, stable, specific, and time-saving, avoiding complex procedures.

Conclusions:

• The luminol-functionalized AuNP-based ECL immunosensor offers a highly sensitive and efficient platform for hIgG detection.
• The amplification strategies involving AuNPs and the biotin-streptavidin system significantly enhance the ECL signal.
• The method shows excellent potential for practical application in detecting hIgG in human serum samples.