2.8. Characterization of Size and Zeta Potential of Nanoparticles

The hydrodynamic diameter of NPs was measured before and after lyophilization; the particle size before the lyophilization of nanoparticles was measured by diluting in distilled water. To measure the diameter of nanoparticles after lyophilization, a suspension of NPs at 0.5 mg/mL of distilled water was prepared by sonication for 1–2 min using a microtip probe sonicator. The intensity-mean Z-averaged hydrodynamic diameter (Deff) and zeta (ζ)-potential of particles were determined using dynamic light scattering (DLS) and a Zetasizer NanoZS (Marvern Instrument Ltd., Malvern, UK). All measurements were performed in automatic mode at 25 °C. Software provided by the manufacture was used to calculate the size, polydispersity indices (PDIs), and ζ-potential of nanoparticles. All measurements were performed at least in triplicate to calculate the mean values ± SD.