Lipid neutron scattering measurements

C. Incoherent Neutron Scattering Measurements of Lipid Dynamics... 

Two physically reasonable but quite different models have been used to describe the internal motions of lipid molecules observed by neutron scattering. In the first the protons are assumed to undergo diffusion in a sphere [63]. The radius of the sphere is allowed to be different for different protons. Although the results do not seem to be sensitive to the details of the variation in the sphere radii, it is necessary to have a range of sphere volumes, with the largest volume for methylene groups near the ends of the hydrocarbon chains in the middle of the bilayer and the smallest for the methylenes at the tops of the chains, closest to the bilayer surface. This is consistent with the behavior of the carbon-deuterium order parameters,. S cd, measured by deuterium NMR ... 

Fig. 18 a Neutron reflectometry data for lipid/PEG-lipid monolayers on a pure D2O subphase. The four reflectivity curves correspond to a pure DSPE monolayer and to mixtures of DSPE and DSPE-PEG2000. In this set of data, all of the DSPE and DSPE-PEG2000 lipid hydrocarbon chains were fully deuterated (case 1). Full lines represent free form fits to the individual measurements, b. Corresponding scattering length densities (J3 (z)) obtained from the fits shown in a [47] (reproduced with permission from the American Chemical Society)... 

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