2.5. Liposome Size Distribution, ζ-Potential, and Stability Studies

The particle size distribution (mean hydrodynamic diameter and polydispersity index) of vesicle dispersions (0.2 mg/mL lipid, in 10 mM PBS, pH 7.40) was measured by dynamic light scattering (DLS) technique (Malvern Nano-ZS; Malvern Instruments, Worcestershire, UK) at 25 °C at a 173-degree angle. Zeta potential (ζ-potential) was measured for the same samples (dispersed in 10 mM PBS, pH 7.40) at 25 °C by the same instrument (utilizing the Doppler electrophoresis technique). The physical stability of some of the vesicle dispersions in buffer was monitored by measuring the mean diameter, polydispersity index (PDI) and ζ-potential at specified time periods during storage at 4 °C for a period of 40 days.