Physical conjugation of (Tri-) block copolymers to liposomes toward the construction of sterically stabilized vesicle systems

The physical conjugation of (tri-) block copolymer molecules to phospholipid vesicle bilayers in order to construct sterically stabilized vesicles can be carried out in two different ways: by allowing the copolymer molecules to freely participate in the small unilamellar vesicle (SUV) formation process along with the lipids or by adding the copolymer molecules to pre-formed small unilamellar liposomes. Structurally and morphologically different copolymer coated vesicle systems occur. The effect on the mean vesicle diameter and the vesicle surface characteristics is monitored by dynamic light scattering and laser Doppler electrophoresis techniques for a wide variety of block copolymer molecules of the PEO-PPO-PEO type (PEOis poly(ethylene oxide); PPOpoly(propylene oxide)).