“…However, labeling may change the conformation stability of proteins, and affect their adsorption behavior or even promote aggregation in proteins [87,95,96]. To avoid the adverse effects of labeling, other "label-free" tools have been employed such as size exclusion chromatography [87,95,96], electrophoresis [128], ellipsometry [132,133], spectroscopy [134], surface plasmon resonance [101], quartz crystal microbalance [135], tensiometry [132], reflectrometry [136], shear rheology [125], surface force apparatus [137] and imaging techniques [138]. However, there are only a few reports where these tools have been employed on oligomers (monomers, dimers etc) of the same protein [87][88][89].…”