Antibody-antigen binding kinetics. A model for multivalency antibodies for large antigen systems

Area of Science:

• Biophysical Chemistry
• Biosensor Technology
• Surface Science

Background:

• Biosensors rely on specific antigen-antibody interactions.
• Understanding binding kinetics is crucial for optimizing biosensor sensitivity and response time.
• Multivalency, the presence of multiple binding sites, significantly influences these interactions.

Purpose of the Study:

• To theoretically analyze the impact of antigen multivalency on binding kinetics for antibody-based biosensors.
• To investigate how antigen and antibody placement (solution vs. surface) affects these kinetics.
• To explore the influence of single-step versus dual-step binding processes.

Main Methods:

• Theoretical modeling of antigen-antibody binding kinetics.
• Analysis of mass transfer-limited conditions.
• Consideration of both solution-phase and surface-immobilized reactants.
• Examination of single-step and dual-step binding models.

Main Results:

• Antigen valency influences reaction order and binding rates, with higher valency generally decreasing these parameters.
• The rate of saturation is rapid (within 20 min).
• Diffusional limitations affect the impact of valency on saturation levels.

Conclusions:

• Antigen multivalency is a critical factor in determining biosensor binding kinetics.
• The findings provide a framework for optimizing biosensor design for various ligand-receptor systems.
• Nondimensional plots facilitate application to diverse antigen-antibody systems.