Supervisor: Fanrice Thalmann
Phospholipids are amphiphilic molecules that self-assemble into bilayers in water, and display complex and diverse physical and chemical properties depending on the composition. The role of lipids in cell membranes is essential. Molecular dynamics allows to investigate bilayer structures at nanometric and picosecond scales, that are either challenging or impossible to reach experimentally.
We focus here on the thermodynamical properties of pure and binary lipid mixtures, using the SPICA coarse-grained lipid force field. Adapting the Kirkwood-Buff theory of solutions to our case, we analyse the density fluctuations in reciprocal space (structure factors) to obtain the thermodynamic parameters of interest, such as the compressibility or the free-energy of mixing in a theory of regular solution description. We then show how to relate in practice the molecular properties of coarsegrained lipid models to the collective thermodynamical properties of the corresponding macroscopic system.
PhD manuscript:
Keywords: lipid bilayers, membranes, structure factor, linear response, Kirkwood-Buff theory, lipid mixtures, theory of regular solutions, numerical simulations, SPICA, LAMMPS
