The protein particle size distribution of the samples was measured
using dynamic light scattering using a Zetasizer Nano series
HT (Malvern Instruments Ltd., Malvern, UK) with Malvern Zetasizer
v.2.2 software (Malvern Instruments Ltd.). Samples
(0.125 mL) were diluted to 25 mL with ultra-pure water. For each
sample, 10 measurements were performed and the output number
was a mean average of the 10 measurements. Experimental parameters
were as follows: temperature, 22 C (120 s equilibration);
material refractive index, 1.39; dispersant refractive index, 1.33;
material absorption, 0.001; viscosity, 0.8872 mPa s. The intensityweighted
mean particle diameter parameter was used for size
measurements and distribution.