A label-free immunoassay using eggshell membrane as matrix and poly(diallyldimethylammonium chloride) as...

Area of Science:

• Biomaterials Science
• Analytical Chemistry
• Immunotechnology

Background:

• Development of sensitive and cost-effective diagnostic tools is crucial for disease monitoring.
• Traditional immunoassays often require labels, increasing complexity and cost.
• Eggshell membrane offers a sustainable and accessible matrix for biosensor development.

Purpose of the Study:

• To develop a label-free immunoassay system utilizing eggshell membrane for human IgG detection.
• To investigate the use of light-scattering signals for quantifying target antigens.
• To evaluate the performance and applicability of the developed method in complex biological matrices like human serum.

Main Methods:

• Immobilization of rabbit anti-human IgG (Ab) onto glutaraldehyde-crosslinked eggshell membrane.
• Capture of human IgG antigen (Ag) and poly(diallyldimethylammonium chloride) (PDDA) via immunoreactions and electrostatic interactions.
• Detection of light-scattering signals using a standard spectrofluorometer.

Main Results:

• A linear relationship was observed between light-scattering intensity and human IgG concentration (5.00-500 ng/mL, r = 0.995).
• The limit of detection (LOD) for human IgG was determined to be 2.31 ng/mL (S:N = 3).
• Successful determination of IgG in human serum samples, showing good agreement with a conventional immunonephelometric method.

Conclusions:

• The developed eggshell membrane-based immunoassay is a sensitive and label-free method for human IgG quantification.
• This approach offers a cost-effective and sustainable alternative for diagnostic applications.
• The method demonstrates potential for reliable IgG determination in clinical serum samples.