title: On the dynamics of molecular self-assembly and the structural analysis of bilayer membranes using coarse-grained molecular dynamics simulations.
abstract: We present a molecular dynamics simulation study of the self-assembly of coarse-grained lipid molecules from unbiased random initial configurations. Our lipid model is based on a well-tried CG polymer model with an additional potential that mimics the hydrophobic properties of lipid tails. We find that several stages of self-organization of lipid clusters are involved in the dynamics of bilayer formation and that the resulting equilibrium structures sensitively depend on the strength of hydrophobic interactions hc of the lipid tails and on temperature T. The obtained stable lipid membranes are quantitatively analyzed with respect to their local structure and their degree of order. At equilibrium, we obtain self-stabilizing bilayer membrane structures that exhibit a bending stiffness κB and compression modulus KC comparable to experimental measurements under physiological conditions. We present a phase diagram of our lipid model which covers a sol-gel transition, a liquid (or gel-like) phase including stable bilayer structures and vesicle formation, as well as a quasi-crystalline phase. We also determine the exact conditions for temperature T and degree of hydrophobicity hc for stable bilayer formation including closed vesicles.
authors.affiliation: Fraunhofer-Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI, Eckerstrasse 4, 79104 Freiburg, Germany; Albert-Ludwigs University of Freiburg, Department of Applied Mathematics, Hermann-Herder-Strasse 10, 79104 Freiburg, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Schindler
authors.affiliation: Albert-Ludwigs University of Freiburg, Department of Applied Mathematics, Hermann-Herder-Strasse 10, 79104 Freiburg, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Kröner
authors.affiliation: Fraunhofer-Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI, Eckerstrasse 4, 79104 Freiburg, Germany; Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland. Electronic address: martin.steinhauser@emi.fraunhofer.de.
authors.forename: Martin O
authors.initials: MO
authors.lastname: Steinhauser
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D044367:Phase Transition
chemical_list: D008051:Lipid Bilayers
keywords: Bio-membranes; Coarse-graining; Molecular dynamics simulations; Phase diagram; Self-assembly; Structural properties