How can you measure binding affinity from a tiny, low-concentration protein sample? In this Fidabio webinar, the head of biophysics at the Biozentrum, University of Basel, shows how Flow Induced Dispersion Analysis (FIDA) measures binding affinity, molecular size and sample quality when methods like ITC, SPR and mass photometry fall short. FIDA measured a kinase conformational change in 30 minutes (matching days of analytical ultracentrifugation), determined a weak protein–protein dissociation constant (HCP–TagF) that ITC, SPR and mass photometry had missed, resolved oligomerisation of an AI-designed binder, quantified antibody binding to micellar nanoparticles, and revealed correctly folded nanobodies that dynamic light scattering had mistaken for pure aggregate. It is an example of using FIDA to measure binding affinity, size and sample quality for challenging biophysical samples.