OBJECTIVES

We intended to study the influence of natural osmolytes urea and TMAO on the fluidity and stability of lipid model membranes by determining the structure of the phases formed in the lipid dispersions. In this way, we expect to determine whether a dominant interaction of these solutes takes place on the lipids, or more indirectly, by affecting the properties of the aqueous region near the headgroup surface. Small and wide angle X-ray scattering (SAXS/WAXS) thermal scans enable us to determine the number of phases in each system, their transitions and respective reversibility. SAXS/WAXS identifies these structures and provide the dimensions of their lattices. Differential scanning calorimetry (DSC) provides the phase transition temperatures and the respective energy involved in such processes.