title: Thermodynamic and structural characterization of a mixed perfluorocarbon-phospholipid ternary monolayer surfactant system.
abstract: Pulmonary lung surfactant is a mixture of surfactants that reduces surface tension during respiration. Perfluorinated surfactants have potential applications for artificial lung surfactant formulations, but the interactions that exist between these compounds and phospholipids in surfactant monolayer mixtures are poorly understood. We report here, for the first time, a detailed thermodynamic and structural characterization of a minimal pulmonary lung surfactant model system that is based on a ternary phospholipid-perfluorocarbon mixture. Langmuir and Langmuir-Blodgett monolayers of binary and ternary mixtures of the surfactants 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) and perfluorooctadecanoic acid (C18F) have been studied in terms of miscibility, elasticity and film structure. The extent of surfactant miscibility and elasticity has been evaluated via Gibbs excess free energies of mixing and isothermal compressibilities. Film structure has been studied by a combination of atomic force microscopy and fluorescence microscopy. Combined thermodynamic and microscopy data indicate that the ternary monolayer films were fully miscible, with the mixed films being more stable than their pure individual components alone, and that film compressibility is minimally improved by the addition of perfluorocarbons to the phospholipids. The importance of these results is discussed in context of these mixtures' potential applications in pulmonary lung surfactant formulations.
authors: Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan, Canada S7N 5C9.
authors: Ala'a F
authors: AF
authors: Eftaiha
authors: Sophie M K
authors: SM
authors: Brunet
authors: Matthew F
authors: MF
authors: Paige
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D011663:Pulmonary Surfactants / Q000737:chemistry*; D013499:Surface Properties; D013500:Surface Tension; D013816:Thermodynamics
chemical_list: D005466:Fluorocarbons; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine