Several different experimental methods are used to probe thermodynamic stability of amyloid fibrils (Table ) . These include methods based on separation of the two species from each other (e.g., ultracentrifugation), or those detecting the spectroscopic or scattering signatures from mixtures of fibrils and soluble protein (e.g., ThT, DSF, SLS). Ultracentrifugation, followed by quantification of soluble protein in the supernatant, is considered a standard method for the quantification of the solubility at any given set of conditions. Despite being conceptually simple and straightforward, it is time-consuming and has relatively low throughput. Furthermore, in our study, we failed to separate extensively sonicated fibrils from monomer even by centrifugation at 180,000 x g for 1 hour. The resulting supernatant was ThT positive, indicating presence of residual fibrils or oligomers (SI figure ).