Antibody-antigen interaction on polystyrene: an in situ ellipsometric study

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Immunology

Background:

• Antibody immobilization on surfaces is key for diagnostic assays.
• Accurate quantification of adsorbed antibodies is essential for assay reliability.
• Ellipsometry offers a label-free method for monitoring surface adsorption.

Purpose of the Study:

• To quantify antibody adsorption onto polystyrene surfaces using ellipsometry.
• To evaluate the stability and binding characteristics of adsorbed antibodies.
• To assess the suitability of ellipsometry for monitoring antibody layers in diagnostics.

Main Methods:

• Ellipsometry was employed to monitor the adsorption of human IgG, bovine IgG, and goat anti-human IgG onto commercial polystyrene slides.
• Theoretical models were used to analyze ellipsometric data for adsorbed amount and layer thickness.
• Irreversibility, consecutive binding, and stability against drying and surfactant were investigated.

Main Results:

• Antibody adsorption resulted in layers with an adsorbed amount of 2.0-2.3 mg/m² and thickness of 10-16 nm.
• Adsorbed antibodies demonstrated irreversible binding to the polystyrene surface.
• Consecutive binding experiments showed approximately 50% binding efficiency and multi-epitope binding.

Conclusions:

• Ellipsometry is a precise method for monitoring antibody adsorption and layer formation on polystyrene.
• Adsorbed antibody layers exhibit irreversible binding and relative stability, suitable for diagnostic applications.
• The study provides quantitative data on antibody adsorption relevant to solid-state immunoassay development.