Wetting properties of dioleoyl-phosphatidyl-choline bilayers in the presence of trehalose: an X-ray diffraction study.

The combined effect of trehalose and temperature on the wetting properties of L-alpha-dioleoyl-phosphatidyl-choline (DOPC) model membranes in excess aqueous solutions has been analyzed by X-ray diffraction and extended electron density map reconstruction. At room temperature, DOPC in excess water forms a fluid lamellar L(alpha) phase. In the presence of trehalose, no phase transitions occur, but repeat and intermembrane distances increase considerably.

Rigidity and spontaneous curvature of lipidic monolayers in the presence of trehalose: a measurement in the DOPE inverted hexagonal phase.

Trehalose is a sugar which plays an important protectant role in organisms against damage due to dehydration. To explore the basic molecular mechanism which governs the protective function exerted on lipid membranes, X-ray diffraction and osmotic stress experiments have been performed on L: -alpha-dioleoyl-phosphatidyl-ethanolamine (DOPE) in trehalose solutions of different concentrations. In pure water, DOPE forms an inverted hexagonal (H(II)) phase; in sugar solutions, a strong dehydration, which induces a large reduction of the H(II) lattice parameter, has been detected, but nevertheless no phase transitions occur.

Lipid-based supramolecular systems for topical application: a preformulatory study.

This article describes the production and characterization of monoglyceride-based supramolecular systems by a simple processing technique, avoiding time-consuming procedures, high energy input, and the use of organic solvents. A preformulatory study was performed to study the influence of the experimental parameters on the production of monoglyceride-based disperse systems. In particular the effects of (1) stirring speed, (2) type and concentration of monoglyceride mixture, and (3) type and concentration of surfactant were investigated on the recovery, fraction of larger particles, mean diameter, and shape of smaller particles (so called nanosomes).

Compressing inverse lyotropic systems: Structural behavior and energetics of dioleoyl phosphatidyl ethanolamine.

The pressure effects on the stability and energetics of lipid phases in the L-alpha-dioleoyl phosphatidyl ethanolamine (DOPE)-water system are presented. Using synchrotron diffraction experiments, performed at a wide range of concentrations, pressure-induced transitions from the inverse hexagonal (H(II)) to the lamellar L(alpha) phase and from the L(alpha) to the lamellar L(beta) phase are demonstrated. Moreover, in the most dehydrated samples an intermediate phase is found between the H(II) and the L(alpha) phases, confirming that the lamellar-to-nonlamellar phase transition occurs through key intermediate structures.