Analysis of the Phospholipid Transport Nanosystem Structure using Small Angle X-Ray Scattering

The structure of aqueous dispersions of phospholipid transport nanosystem (PhTNS) based on soybean phospholipids, developed at the Institute of Biomedical Chemistry (Moscow, Russia), was studied by the method of small-angle X-ray scattering. The PhTNS concentrations in water were 20, 25, 31.25, and 37.5%. The structural parameters of vesicles (inner radius, thicknesses of the regions of hydrophobic tails and polar heads) were determined in the “core multi shell model” approximation with variations in the scattering length densities of vesicle different parts, as well as the solution that was inside and outside the vesicle. A difference in the photon scattering length densities was detected between the solution volume and the inner region of the vesicle, due to the uneven maltose dissolution, which is part of PhTNS. With an almost constant thickness of the lipid bilayer, a decrease in the vesicle radius from ~150 to ~130 Å was observed with increasing concentration of the system which due to increasing osmotic pressure. The hydrophobic volume of vesicles was determined to be 7.45 × 10⁶ ų at the lowest concentrations of 20% and 5.85 × 10⁶ ų at the highest concentration of 37.5%.