While it was possible to derive accurate particle sizes from MALLS785nm, DLS provided too low average sizes for LNPs (Table ). In DLS, the change in scattered light intensity over time is used as a measure for the movement of particles caused by Brownian motion, which is correlated with the diffusion coefficient and size of the particles. Consequently, online DLS measurements must ensure conditions that accurately capture the Brownian motion of a particle in flow. This is usually done by adjusting detector flow rate to ensure proper residence time of the particle in the flow cell.