The thermodynamical and structural influence of ionic liquids in biomimetic membrane models

Abstract

In this research project we will study the influence of different ionic liquids in the structural and thermodynamic properties of biomimetic membrane systems. Biomimetic membranes have been widely used in recent decades to emulate, in a simple approach, the plasma membrane of cells and the membrane of different organelles. The Ionic Liquids in turn, are salts composed of an organic ion (or counterion) and are in the liquid form at temperatures below 100 ° C. In this research project we will use lipids that represent a model (in a first approximation) to the composition of cell membranes in eukaryotes, studying the influence of different concentrations of ILs in the structural and thermodynamic properties of these systems. To do so, we will use mainly two different techniques: steady-state fluorescence anisotropy, through the probe DPH (1,6-diphenyl-1,3,5-hexatriene), and scattering X-ray small angle, SAXS. The probe DPH is widely used to determine the lipid phase transition temperatures under different compositions. The measured anisotropy of the fluorescence emission for this probe is closely related to the microviscosity of the surrounding region and are therefore sensitive to the presence of lipid gel or fluid phase. SAXS technique is in turn an important tool in the study of the structural properties of relevant biological systems. In particular, SAXS technique will be able to provide us with information about the thickness of the lipid bilayer and the electron densities in each region. This project will be developed by Ms. Natalia Fernandes de Oliveira, under my guidance. Ms. Natalia has an excellent academic performance (history attached to this proposal) and has been working with me for almost a year. Moreover, it is important to note that this research project is part of a regular project (2015 / 15822-1) under my coordination and supported by FAPESP.