By Xenocs
DLS relies on the principle of Rayleigh scattering, which states that the intensity of light scattered by a particle is directly proportional to the sixth power of its diameter [10]. Thus, large-diameter NPs scatter light orders of magnitudes more intensively than smaller ones making DLS a technique with limited capabilities of resolving bimodal and heterogeneous ensembles of particles. Moreover, DLS may not accurately represent particles with non-spherical or irregular shapes, as it simplifies their geometry to that of spherical non-interacting particles for analysis employing the Stokes-Einstein equation. While DLS offers cost-effective and straightforward size analysis, its limitations become apparent when dealing with complex particle distributions, often providing a simplified representation (e.g assumption of spherical particle geometry). Additionally, in contrast with SAXS, DLS is highly sensitive to sample concentration. At higher concentrations, particles tend to interact more strongly, leading to increased multiple scattering effects. This can result in distorted data and inaccurate particle size measurements. To mitigate these effects, DLS typically requires samples to be highly diluted, often to dilution factors of 1/1000 or even lower. This extensive dilution process can be time-consuming and may not be feasible for samples with limited availability or stability.
