Quantitative characterization of antibody-antigen interactions using mass photometry and the StreamlineMP Interactions Module
Mass photometry provides information on molecular interaction stoichiometry beyond the simple 1:1 interactions usually determined by surface plasmon resonance (SPR) and biolayer interferometry (BLI). By resolving free proteins and complexes of different stoichiometries in solution, it reveals interactions that are largely invisible to surface-based methods.
This application note illustrates how mass photometry, in combination with the StreamlineMP Interactions Module, reveals oligomerically resolved affinities using nanograms of sample and 60-second measurements. Mass photometry revealed differences in interaction mechanisms and extracted KD values associated with individual binding steps – from measurements acquired once equilibrium had been reached.
These results demonstrate how mass photometry provides information beyond what can be gained from SPR and BLI by revealing the species present in solution and providing context for interpreting binding responses, selecting binding models and designing experiments. We also summarize best practices for obtaining reliable affinity measurements using mass photometry.