The particle size of IDF and MIDFs was determined by Nicomp
380/ZLS Zeta potential/Particle Sizer (PSS Nicomp, Santa Barbara,
USA) based on dynamic light scattering (Chen, Wu et al., 2014).
Samples were diluted 1: 10 (v/v) with deionized water. The
dispersion was shaken on a vortex mixer for 3 min, and then
applied to Particle Sizer immediately. Particle size refers to the
corresponding intensity distribution calculated by NICOMP Distribution
Analysis. All measurements were carried out at 25 C.