TABLE 1.

Summary of the physical characteristics considered for the lipid vesicles used

Model system of membranes	Mean diameter (nm)	μ
SUV	30	6.0 × 103
LUV	100	8.2 × 104

The calculation of the average number of lipids in a single liposome, μ, was based upon a 4.5-nm bilayer thickness, an average surface area occupied by each phospholipid molecule of 0.7 nm² (fluid phase) (Marsh, 1990; Nagle and Wiener, 1988) and assuming an homogeneous population of spherical lipid vesicles. It was also considered that there were no phospholipid packing constraints in the smaller vesicles and that the temperature did not influence the average number of lipids per liposome (Cornell et al., 1981).