Dynamic light scattering (Fig. ) and TEM (Fig. ) analysis of purified liposomes containing encapsulated carboxyfluorescein (CF) as a fluorescent probe reveals that a population of liposomes with a mean particle size around 200 nm was prepared. At a lipid concentration of 5 mg/ml, the total surface area of such liposome is approximately 2 m 2 /ml, which represents an increase by a factor of 10 4 compared to traditional permeation assays with planar membranes. The liposomes were colloidally stable; their zeta potential determined by electrophoretic light scattering was (-12.4 ± 1.3) mV. The negative surfaces charge is consistent with the fact that a negatively charged phospholipid DPPG was used as part of the membrane mix.