Gold nanoparticle-based immunoassay by using non-stripping chemiluminescence detection

Area of Science:

• Analytical Chemistry
• Biochemistry
• Immunology

Background:

• Accurate quantification of human immunoglobulin G (IgG) is crucial for diagnosing various diseases.
• Existing chemiluminescence immunoassay (CLIA) methods can be complex, requiring stringent procedures or difficult synthesis.

Purpose of the Study:

• To develop a novel, microplate-compatible chemiluminescence immunoassay for human IgG determination.
• To utilize a luminol-AgNO(3)-gold nanoparticle CL system for enhanced sensitivity and simplicity.

Main Methods:

• Immobilization of goat-anti-human IgG primary antibody on polystyrene microwells.
• Formation of a sandwich-type immunocomplex with human IgG and a gold-labeled secondary antibody.
• Triggering chemiluminescence via the gold label's catalytic effect on the luminol-AgNO(3) reaction.

Main Results:

• The CL intensity showed linearity with the logarithm of human IgG concentration from 25 to 5000 ng/mL.
• A detection limit of 12.8 ng/mL (approx. 80 pM) was achieved at S/N = 3.
• The developed method demonstrated simplicity, time-saving advantages, and potential for automation.

Conclusions:

• The novel CL immunoassay provides a simple, sensitive, and automatable method for human IgG determination.
• This approach avoids complex stripping procedures or challenging synthesis steps common in other gold-labeled CLIA methods.
• The assay is promising for the routine analysis of clinically significant bioactive analytes.