- Ruiz Chain dependence in phospholipid interactions : A thermodynamic study of mixed monolayers

J. Sánchez-González M.A. Cabrerizo-Vilchez M.J. Gálvez-Ruiz ( ) Grupo de Fı́sica de Fluidos y Biocoloides Departamento de Fı́sica Aplicada Universidad de Granada 18071 Granada Spain E-mail: [email protected] Abstract The interactions between three of the major phospholipids in biomembranes, distearoylphosphatidylethanolamine, distearoylphosphatidylcholine and sphyngomyelin, forming monolayers at the air—water interface, are studied. Following the Goodrich [1] thermodynamic formulation, a quantitative analysis on these interactions is carried out. The general conclusion reached is that, depending on the molecular structure of the lipid and the experimental temperature, significant interactions occur between lipid molecules. One hypothesis is the possibility that, the usual miscibility analysis, in mixed monolayers, could be inadequate to provide information on the interactions in the systems which the hydration forces are significant, is advanced.