Small-angle neutron scattering from large unilamellar vesicles: An improved method for membrane thickness determination

Small-angle neutron scattering (SANS) measurements were performed on large unilamellar vesicles (LUVs) in order to investigate solute effects on membr ane properties. Although SANS is a well established technique for the measu rement of membrane thickness in unilamellar vesicles, earlier measurements have depended on approximate treatments of the scattering function and have suffered from effects of multilamellarity or difficulty in sample preparat ion. More recent studies of temperature induced thickness changes in DPPC L UVs which have included explicit treatment of the full scattering function were complicated by disparities between the predicted and measured scatteri ng curves. Here, we reexamine theoretical descriptions of SANS from LUVs. M otivated by our observations, we then introduce a new method for interpreta tion of SANS data, which we compare to established techniques and apply to our measurements.