<p><b>(A)</b> Radially integrated background-subtracted scattering data (symbols) of DMPC:DPPC NSSL with and without drug, at 4 and 37°C, as indicated in the figure. Note that the curves are shifted in the intensity axis only for clarity of presentation. The solid curves are the corresponding form-factor models of a stack of infinite slabs with a Gaussian electron density profile along the vertical direction. <b>(B)</b> The electron density profiles of the DMPC:DPPC NSSL bilayers (with and without drug at 4 and 37°C) along the normal direction. The density profiles are obtained by fitting the scattering data to the models (see A) with the software X+, choosing a Gaussian electron density profile for the liposome membrane [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130442#pone.0130442.ref040" target="_blank">40</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130442#pone.0130442.ref041" target="_blank">41</a>]. The profile is almost symmetric and very slightly affected by the temperature or the presence of the drug. The arrows point to the profile of the inner and outer PEG layers. <b>(C)</b> The integrated scattering patterns as a function of the magnitude of the scattering vector, q, for EPC liposomes. Note that the curves are shifted in the intensity axis for clarity of presentation. The scattering curves of the EPC NSSL with and without drug, at 4 and 37°C are very similar. These curves are analyzed using the software X+, as in (A). The liposome bilayer is described by a Gaussian electron density profile. <b>(D)</b> The electron density profile in the direction normal to the membrane, calculated using the software X+, is presented for EPC NSSL, with and without drug at 4 and 37°C. The density profile of the membrane is almost unaffected by the temperature or the presence of the drug. Notice that this profile is asymmetric, suggesting that the inner and the outer PEG layers (pointed by an arrow) of the liposome are different.</p
