Understanding interactions between immunoassay excipient proteins and surfactants at air-aqueous interface

- Interfacial shear rheology of excipient proteins was studied using Du Noüy ring.
- Globular BSA formed stronger, and disordered caseinate formed weaker networks.
- Concentration dependent displacement of proteins by nonionic surfactants was observed.
- Surface tension characterization complimented the shear rheology observations, yet provided distinct information about protein-surfactant interactions.