Characterization of labeled reagents in ligand-binding assays by a surface plasmon resonance biosensor

Aim: Ligand-binding assay (LBA) reagent labeling may change the binding characteristics of the reagent to its target and degrade its performance in LBAs. Results: A surface plasmon resonance (SPR) biosensor was used to evaluate the impact of the biotin labeling process on reagent-binding kinetics and affinity for a specific target. The SPR results demonstrate that the biotin molar challenge ratio affects both association and dissociation rates for the labeled reagent binding to its target. The SPR results also predict the labeled reagent performance in LBAs. Conclusion: The methodology used in this study provides an example of using an SPR biosensor as an efficient way to analytically and functionally characterize critical reagents and to understand their performance postmodification in LBAs.