Optimizing Kinetics Assays to Prevent Avidity Effects

A fundamental understanding of the differences between affinity and avidity is essential when designing and developing assays for antibody development. This application note discusses the phenomena of affinity and avidity as measured with a label-free biosensor approach and how to recognize and resolve issues arising from interactions that contain a bivalent or multivalent component. Assay design plays a critical role in the ability to determine the correct binding kinetics and affinity values and therefore, key parameters including assay orientation, valency (mono- or multivalent), ligand surface density and non-specific binding (NSB) are discussed. Affinity and avidity are closely related parameters, which when considered early in assay design can ensure the user can generate the desired assay parameters between the interacting molecules.