Dynamic light scattering
DLS was used to detect aggregates in the size range from about 1 nm to 1 µm. DLS was performed on a Malvern Zetasizer Nano (Malvern, Herrenberg, Germany). 500 µL of each sample in a concentration of 10 mg/mL was analyzed in plastic cuvettes at 25◦C using the automatic mode (n=3). Z-average diameter and polydispersity index were calculated using Dispersion Technology Software version 7.03 (Malvern, Herrenberg, Germany).