Influence of a neoglycolipid and its PEO-lipid moiety on the organization of phospholipid monolayers

International audienceThe 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, GlcNAcE3G28 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 (E3G28) 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 E3G28, 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 (Delta G(exc)) for GlcNAcE(3)G(28)-phospholipid mixtures enabled us to predict the stability of such systems

SELF-ASSEMBLING SYSTEMS OF THE AMPHIPHILIC CATIONIC PER-6-AMINO-BETA-CYCLODEXTRIN 2,3-DI-O-ALKYL ETHERS

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Physico-chemical surface characterization of Hyaluronic Acid derivatives as a new class of biomaterials

Three hyaluronic acid derivatives with different types and/or percentages of esterification, were analyzed by means of static contact angle measurements, SEM, ESCA, ATR/FT-IR, WAXS, DSC and TGA. The physico-chemical characterization of the three different samples, in both dry and wet state, was provided in terms of surface and bulk properties. ESCA and infrared analyses showed that the surface composition of all samples differs from that of the bulk. The hydrophilic-hydrophobic character of the samples changed according to the chemical composition as shown by ESCA and contact angle measurements. Both infrared and contact angle measurements reveal that surface restructuring occurred upon hydration for all the samples and the greater the hydrophilic character of the sample, the greater and faster the restructuring phenomenon. A clear picture of the different types of chemical groups has been established at different depth for the three material