Modification of Phosphatidylcholine Liposomes with Poly(ethylene oxide)-Substituted Lipids

Modification of egg phosphatidylcholine (eggPC) and dimyristoylphosphatidylcholine liposomes with poly(ethylene oxide)-substituted lipids [PEO-lipid(m,n); m and n mean, respectively, the chain length of alkyl group and the number of PEO segments]. Morphologies of these supermolecules were investigated by means of laser dynamic light scattering and transmission electron microscopy. Reconstitution of the PEO-lipid to eggPC liposome was possible below 40–50 mol% of total lipids for PEO-lipid(12,5), and 30–40 mol% for PEO-lipid(12,13) and PEO-lipid(12,31). Effective encapsulation of FITC-dextran (1.96 kDa) into the liposome was obtained using the eggPC liposome modified with PEO-lipid. This PEO-modified liposome showed sufficient barrier function to water-soluble polymers such as dextran. Through various studies, it was found that PEO-lipid(12,13) is relatively compatible for modifying conventional eggPC liposome.