The amount of water in therapeutic nanoparticles (NPs) is of great importance to the pharmaceutical industry, as water content reflects the volume occupied by the solid components. For example, certain biomolecules, such as mRNA, can undergo conformational change or degradation when exposed to water. Using static light scattering (SLS) and dynamic light scattering (DLS), we estimated the water content of NPs, including extruded liposomes of two different sizes and polystyrene (PS) Latex NPs. In addition, we used small-angle neutron scattering (SANS) to independently access the water content of the samples. The water content of NPs estimated by SLS/DLS was systematically higher than that from SANS. The discrepancy is most likely attributed to the larger radius determined by DLS, in contrast to the SANS-derived radius observed by SANS. However, because of low accessibility to the neutron facilities, we validate the combined SLS/DLS to be a reasonable alternative to SANS for determining the water (or solvent) content of NPs.
Differential scanning calorimetry (DSC) of dipalmitoyl phosphatidylcholine (DPPC), dihexanoyl phosphatidylcholine, and dipalmitoyl phosphatidylglycerol bicelles reveals two endothermic peaks. Based on analysis of small angle neutron scattering and small angle X-ray scattering data, the two DSC peaks are associated with the melting of DPPC and a change in bicellar morphologynamely, either bicelle-to-spherical vesicle or oblate-to-spherical vesicle. The reversibility of the two structural transformations was examined by DSC and found to be consistent with the corresponding small angle scattering data. However, the peak that is not associated with the melting of DPPC does not correspond to any structural transformation for bicelles containing distearoyl phosphatidylethanolamine conjugated with polyethylene glycol. Based on complementary experimental data, we conclude that membrane flexibility, lipid miscibility, and differential solubility between the long- and short-chain lipids in water are important parameters controlling the reversibility of morphologies experienced by the bicelles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.