Protein adsorption kinetics from single- and binary-solution

Comparison of protein mass-adsorption-rates to rates-of-change in interfacial tensions reveals that mass adsorption is decoupled from interfacial energetics. This implies that energy-barrier theories describing protein-adsorption kinetics do not accurately capture the physics of the process. An alternative paradigm in which protein molecules rapidly diffuse into an inflating interphase which subsequently slowly shrinks in volume, concentrating adsorbed protein and causing slow concomitant decrease in interfacial tensions, is shown to be consistent with adsorption kinetics measured by solution depletion and tensiometry. Mass adsorption kinetics observed from binary-protein solution is compared to adsorption kinetics from single-protein solution, revealing that organization of two different-sized proteins within the interphase can require significantly longer than that adsorbed from single-protein solution and may require expulsion of initially adsorbed protein which is not observed in the single-protein case.