Protein dynamic light scattering4/27/2023 ![]() By using DLS, it was possible to characterize the diffusion coefficients of diluted protein/HA binary and ternary systems. The DLS and MD simulation results indicated strong attractive intermolecular interaction existed between LYS and HA molecules, especially at low ionic strength. On the contrary, for LYS/HA/solvent ternary systems, ( D 1 DLS + D 2 DLS) were significantly smaller than ( D LYS + D HA) and the diffusion coefficients in binary and ternary systems exhibited an opposite trend with respect to ionic strength change. For OVA/HA/solvent ternary systems, the sum of two eigenvalues ( D 1 DLS + D 2 DLS) was slightly smaller compared to ( D OVA + D HA), where D OVA and D HA were the diffusion coefficients in their binary systems. The results of binary systems showed that at low ionic strength, the diffusion coefficients of protein and HA increased linearly with concentration at high ionic strength, the diffusion coefficients of OVA and LYS were independent on protein concentration for HA, the positive linear relationship between diffusion coefficient and concentration existed at high and low ionic strengths, but the slope at high ionic strength was smaller compared to that at low ionic strength. Whereas, for protein/HA/solvent ternary systems, the two eigenvalues of the mutual diffusion coefficient matrix were obtained from ACF curve fitting. ![]() For protein/solvent and HA/solvent binary systems, the diffusion coefficients of protein or HA were obtained from autocorrelation function (ACF) curve fitting. Lett, 32(2), 37 (1974).This study aimed to investigate the diffusivities of lysozyme (LYS), ovalbumin (OVA), and hyaluronic acid (HA) in buffered solvents using dynamic light scattering (DLS). Huglin, in Light scattering from protein solutions, edited by M. Google Scholarįor a discussion of the noise in the correlation function, see W. Schmitz, Dynamic Light Scattering by Macromolecules ( Academic, New York, 1990). Lide, CRC Handbook of Chemistry and Physics ( Taylor and Francis, 2004). Particle concentration, type of ions in the medium can. (82)90173-4, Google Scholar Crossref, ISI DLS can be used to characterize the size of various particles including proteins and small compounds. (82)90174-6, Google Scholar Crossref, ISI Crothers, Physical Chemistry with Applications to Life Sciences ( The Benjamin/Cummins, Menlo Park, 1979). Pecora, Dynamic Light Scattering with Applications to Chemistry, Biology, and Physics ( Dover, Mineola, NY, 2000). DLS yields a lower bound of the cluster lifetime, which may be orders of magnitude lower than the real one. We show that DLS yields a reliable width of the cluster size distribution only if the cluster concentration is above 10 9 cm −3 and their volume fraction is above 10 −6. We put forth an alternative method to determine the aggregates’ sizes, concentrations, and volume fractions. The CONTIN algorithm, often employed to process DLS data, may, in some instances, produce non-physical results. The related underestimate of the cluster concentration is ∼10 ×. The factor of overestimation depends on the shape of the size distribution and is ∼1.6 × in the studied solution. We show that because of the sixth power dependence of the scattered light intensity on the size of the scatterers, DLS overestimates the mean size of the clusters. We compare the results of DLS to those of Brownian microscopy. We use as an example a solution of the protein lysozyme in which dense liquid clusters of radius about 100 nm reproducibly exist. Here, we explore the veracity of the aggregate sizes, size distribution widths, concentrations, and lifetime resulting from DLS. Dynamic light scattering (DLS) is often used to monitor aggregation in protein solutions.
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