Quantitative analysis of immunological reactions on silicon surfaces by multiple-angle Brewster angle reflectometry

Area of Science:

• Biomedical Engineering
• Optical Physics
• Immunochemistry

Background:

• Quantitative analysis of immunological reactions is crucial for diagnostics.
• Existing biosensing methods may lack sensitivity or require complex sample preparation.
• High refractive index substrates offer potential for enhanced optical sensing.

Purpose of the Study:

• To develop and evaluate a novel optical biosensing instrument for quantitative analysis of immunological reactions.
• To investigate the binding kinetics and concentration dependence of antibody-antigen interactions.
• To assess the performance of the biosensor using different wavelengths of laser light.

Main Methods:

• Development of an optical biosensing instrument based on multiple-angle Brewster angle reflectometry (MABAR).
• Utilizing polarized laser light (red and green He-Ne) incident on high refractive index silicon substrates.
• Investigating the binding of anti-human serum albumin (a-HSA) to human serum albumin (HSA) coated surfaces.

Main Results:

• The MABAR instrument successfully quantified immunological reactions on sensitized surfaces.
• Concentration dependence and reaction kinetics of antibody-antigen complex formation were determined.
• A significant increase in sensing sensitivity was observed when using green laser light compared to red light.

Conclusions:

• The developed optical biosensing instrument provides a sensitive method for quantitative analysis of immunological reactions.
• MABAR is effective for studying antibody-antigen interactions and reaction kinetics.
• The choice of laser light wavelength (green) can significantly improve biosensor sensitivity.