SAXS experiments were performed with SAXS Xenocs-XeussTM (Xenocs, Sassenage, France) with a GENIX source and Fox2D mirrors. Collimation was performed using two sets of scatterless slits that provide a high flux (approximately 0.5 × 108 ph/s/mm2) with very low parasitic scattering. Data treatment was performed using the software package SUPERSAXS, and the final scattering intensity was normalized to an absolute scale based on water as the primary standard. The normalization of the data to an absolute scale permitted the estimation of the average molecular weight of the particles [26]. The methodological details are described in the Supplementary Materials (B) SAX Structure Characterization.