title: Toward Quantitative Coarse-Grained Models of Lipids with Fluids Density Functional Theory.
abstract: We describe methods to determine optimal coarse-grained models of lipid bilayers for use in fluids density functional theory (fluids-DFT) calculations. Both coarse-grained lipid architecture and optimal parametrizations of the models based on experimental measures are discussed in the context of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers in water. The calculations are based on a combination of the modified-iSAFT theory for bonded systems and an accurate fundamental measures theory (FMT) for hard sphere reference fluids. We furthermore discuss a novel approach for pressure control in the fluids-DFT calculations that facilitates both partitioning studies and zero tension control for the bilayer studies. A detailed discussion of the numerical implementations for both solvers and pressure control capabilities are provided. We show that it is possible to develop a coarse-grained lipid bilayer model that is consistent with experimental properties (thickness and area per lipid) of DPPC provided that the coarse-graining is not too extreme. As a final test of the model, we find that the predicted area compressibility moduli and lateral pressure profiles of the optimized models are in reasonable agreement with prior results.
authors.affiliation: Colder Insights Corp. , Shoreview, Minnesota, 55126, United States.
authors.forename: Laura J Douglas
authors.initials: LJ
authors.lastname: Frink
authors.affiliation: Sandia National Laboratories , Albuquerque, New Mexico 87185, United States.
authors.forename: Amalie L
authors.initials: AL
authors.lastname: Frischknecht
authors.affiliation: Sandia National Laboratories , Albuquerque, New Mexico 87185, United States.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Heroux
authors.affiliation: Sandia National Laboratories , Albuquerque, New Mexico 87185, United States.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Parks
authors.affiliation: Sandia National Laboratories , Albuquerque, New Mexico 87185, United States.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Salinger