Analytical Ultracentrifugation in Different High‐Density Media Allows to Assess Heterogeneity of mRNA‐Lipid Nanoparticles

This study demonstrates the capability of analytical ultracentrifugation for assessing the morphological homogeneity of mRNA-lipid nanoparticles. Building on a standard method for density evaluation of nanoparticles, it demonstrates the importance of selecting the appropriate liquid medium for the experiments. Our research reveals the interaction between deuterated buffers and aqueous compartments of lipid-based particles. By investigating the sedimentation behavior of compact solid particles, liposomes, and lipid nanoparticles, we demonstrate that AUC can detect water-loaded cavities in mRNA-loaded lipid nanoparticles. Therefore, we suggest that performing sedimentation velocity experiments both in sucrose-containing buffer and deuterated solvents results in precious information not only on density but also on batch homogeneity and particle morphology.