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Implementation of a Self-Consistent Slab Model of Bilayer Structure in the SasView Suite



Luoxi Tan, James G. Elkins, Brian H. Davison, Elizabeth Kelley, Jonathan Nickels


Slab models are simple and useful structural descriptions which have long been used to describe lyotropic lamellar phases, such as lipid bilayers. Typically, slab models break a bilayer structure into three pieces, an inner solvent-free core and two symmetric outer layers composed of the soluble portion of the amphiphile and associated solvent. This breakdown matches reasonably well to the distribution of neutron scattering length density and therefore is a convenient and common approach for the treatment of small angle scattering data. Here, we report on an implementation of this model within the SasView software suite. Our implementation is focused on the case of lipid bilayers but is intended to provide physical consistency though the area per amphiphile molecule and number of solvent molecules included within the solvent exposed outer layer. The proper use of this model requires knowledge of (or good estimates for) the amphiphile and solvent molecule volume and atomic composition, ultimately providing a self-consistent data treatment with only two free parameters; the area per amphiphile and the number of solvent molecules included in the outer region per amphiphile. We demonstrate the use of this code in the fitting of standard lipid bilayer datasets, obtaining structural parameters consistent with prior literature and illustrating the typical and ideal cases of fitting for neutron scattering data obtained using single or multiple contrast conditions. While demonstrated here for lipid bilayers, this model is intended for more general application to block copolymer, surfactant, and other lyotropic lamellar phase structures.
Journal of Applied Crystallography


slab model, small angle scattering, bilayer, lamellae, data modelling


Tan, L. , Elkins, J. , Davison, B. , Kelley, E. and Nickels, J. (2021), Implementation of a Self-Consistent Slab Model of Bilayer Structure in the SasView Suite, Journal of Applied Crystallography (Accessed April 22, 2024)
Created January 31, 2021, Updated September 7, 2021