The thermodynamic behaviour of mixed cationic-zwitterionic lipid mixtures dioleoyltrimethylammoniumpropanedipalmitoylphosphatidylcholine (DOTAP-DPPC) at different mole fractions have been investigated by means of surface pressure measurements (Langmuir isotherms). Excess Gibbs energies of mixing have been calculated as a function of layer composition and surface pressure. Deviation from ideality evidences different molecular organisation of the two lipids, yielding the formation of cationic lipid domains in a zwitterionic lipid matrix. The stability of the mixed monolayer in the presence of both a simple electrolyte solution (NaCl) and a polyelectrolyte solution (NaPAA of different molecular weights) in the same charge ratio interval has been investigated and the influence of the polymer conformation briefly discussed. (C) 2002 Elsevier; Science B.V. All rights reserved.
Charged lipid monolayers at the air-solution interface: coupling to polyelectrolytes
Gili T;
2003-01-01
Abstract
The thermodynamic behaviour of mixed cationic-zwitterionic lipid mixtures dioleoyltrimethylammoniumpropanedipalmitoylphosphatidylcholine (DOTAP-DPPC) at different mole fractions have been investigated by means of surface pressure measurements (Langmuir isotherms). Excess Gibbs energies of mixing have been calculated as a function of layer composition and surface pressure. Deviation from ideality evidences different molecular organisation of the two lipids, yielding the formation of cationic lipid domains in a zwitterionic lipid matrix. The stability of the mixed monolayer in the presence of both a simple electrolyte solution (NaCl) and a polyelectrolyte solution (NaPAA of different molecular weights) in the same charge ratio interval has been investigated and the influence of the polymer conformation briefly discussed. (C) 2002 Elsevier; Science B.V. All rights reserved.File | Dimensione | Formato | |
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