Polymer-hybridized liposomes anchored with alkyl grafted poly(asparagine)

Polymer-hybridized liposomes (PHLs) of saturated lecithin were formed by association of poly(asparagines) grafted with alkyl chains (PAsn-g-Cn). The thermal, physical, and surface properties of the polymer-hybridized liposomes were examined with varying polymer concentration, alkyl chain length (C8, C12, C18, C22), and degree of substitution (DS) in the polymer. The inclusion of the polymer raised the membrane fluidity of liposomes. By the incorporation of small amount of polymer, the membrane rigidity of liposomes dropped sharply and then increased close to the original level as the polymer concentrations increased in the cases of PAsn-g-C18 and PAsn-g-C22. Also, the membrane rigidity and stability of PHLs increased with alkyl chain length at the same polymer concentration. The surface charge of PHL associated with PAsn-g-C22 was changed by DS of alkyl chains. The polymer bearing long alkyl chains (C12, C18, C22) formed PHLs well at low polymer concentration and the number of disk-shaped polymer–lipid mixed micelles increased with polymer concentration. The anchored polymers induced shifts in gel-to-liquid crystal transition temperature (Tc) of the vesicles and Tc varied with polymer concentration, alkyl chain length, and DS of the polymer.

Polymer-hybridized liposomes (PHLs) of saturated lecithin were formed by association of poly(asparagines) grafted with alkyl chains. The membrane properties of the PHLs were varied with alkyl chain length of polymer.Figure optionsDownload high-quality image (85 K)Download as PowerPoint slideHighlights
► The membrane fluidity of liposomes increases by the inclusion of the alkyl grafted poly(asparagines).
► The membrane rigidity of polymer-hybridized liposomes increases with the alkyl chain length of polymer.
► The anchored polymer induces a shift in Tc of the lipid bilayer.
► The number of polymer–lipid mixed micelles increases with polymer concentration.