Fig 3. Membrane stability and packing depend on lipid and surfactant composition.

A: Graphical representation of calcein leakage across membrane. B: Leakage of calcein from liposomes and niosomes. Green lines: niosomes composed of unsaturated surfactants plus cholesterol; red lines: niosomes composed of saturated surfactants plus cholesterol; black lines: liposomes composed of unsaturated lipids plus cholesterol; blue lines: liposomes composed of saturated lipids plus cholesterol. Representative traces of one out of two experiment are shown. C: Stability of niosomes and liposomes in the presence of Triton X-100. The data are corrected for dilution; line/symbol color as in B. The upper x-axis is for the liposomes composed of saturated lipids plus cholesterol. Representative traces of one out of two experiment are shown. D: Membrane packing of niosomes and liposomes, measured using the environment-sensitive dye laurdan; line/symbol color as in B. The average of two independent experiments is shown. The spectra of the corresponding vesicles without laurdan were used to correct for background signal.