title: Surface thermodynamics study of monolayers formed with heteroacid phospholipids of biological interest.
abstract: The interaction of 1-palmitoy-2-oleoyl-sn-glycero-3-phosphocoline (POPC) and 1-palmitoy-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), two of the major components in biological membranes, were investigated using the monolayer technique at the air-water interface. The pressure-area isotherms indicate that both phospholipids are miscible through all range of compositions. POPE-POPC form stable mixtures, with a minimum for the Gibbs energy of mixing at X(POPC) = 0.4. A virial equation of state was fitted to the experimental values. Positive values found for the second virial coefficient indicate repulsion between POPC and POPE. The interaction parameter was evaluated which indicated that a corresponding decrease in the repulsion occurs when POPC molar fraction is low. This effect suggests the existence of hydrogen bonds between POPE and the water beneath the interface.
authors.affiliation: Departament de Química Física, Universitat de Barcelona, Centre de Bioelectrònica i Nanobiociència (CBEN), Parc Científic de Barcelona, Josep Samitier 1-5, E-08028 Barcelona, Spain.
authors.forename: Oscar
authors.initials: O
authors.lastname: Domènech
authors.forename: Juan
authors.initials: J
authors.lastname: Torrent-Burgués
authors.forename: Sandra
authors.initials: S
authors.lastname: Merino
authors.forename: Fausto
authors.initials: F
authors.lastname: Sanz
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Montero
authors.forename: Jordi
authors.initials: J
authors.lastname: Hernández-Borrell
mesh_terms: D000388:Air; D006860:Hydrogen Bonding; D008081:Liposomes / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D008081:Liposomes; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D014867:Water; C028694:1-palmitoyl-2-oleoylphosphatidylcholine