Influence of a neoglycolipid and its PEO-lipid moiety on the organization of phospholipid monolayers.
The surface properties of the neoglycolipid (GlcNAcE(3)G(28)) and of its PEO-lipid (E(3)G(28)) moiety mixed with phospholipids (dipalmitoylphosphatidylcholine, DPPC; distearoylphosphatidylcholine, DSPC; diarachidoylphosphatidylcholine, DAPC; and dibehenoylphosphatidylcholine, DBPC) were studied in Langmuir monolayers at various mixture compositions and surface pressures. The pi-A isotherms of the pure compounds revealed that because of the presence of the sugar group in its molecule, GlcNAcE(3)G(28) collapsed at a higher surface pressure and occupied a larger molecular area than the PEO-lipid moiety. It was also observed that the presence of the PEO-lipid (E(3)G(28)) in the mixtures triggered a strong alteration of both phospholipid pi-A isotherm profiles and surface diffraction spectra, an indication that the disordering of the initially structured phospholipid monolayers took place. Unlike E(3)G(28), GlcNAcE(3)G(28) did not disorganize phospholipid monolayers but generated a partial segregation of the film-forming components. The calculated excess free energies of mixing (DeltaG(exc)) for GlcNAcE(3)G(28)-phospholipid mixtures enabled us to predict the stability of such systems.
Dynarowicz-Łatka
P
P
Physico-Chimie des Surfaces, UMR CNRS 8612, Université Paris-Sud, Châtenay-Malabry, France.
Rosilio
V
V
Boullanger
P
P
Fontaine
P
P
Goldmann
M
M
Baszkin
A
A
D010743:Phospholipids; D011312:Pressure; D013499:Surface Properties
D010743:Phospholipids