Investigating protein diffusivities in diluted hyaluronic acid solutions using dynamic light scattering

Area of Science:

• Biophysical Chemistry
• Materials Science

Background:

• Understanding molecular diffusion is crucial for biomaterials and drug delivery.
• Proteins like lysozyme (LYS) and ovalbumin (OVA), and hyaluronic acid (HA) are key biomolecules with varying diffusion properties.

Purpose of the Study:

• To investigate the diffusion coefficients of LYS, OVA, and HA in binary and ternary systems using dynamic light scattering (DLS).
• To explore the influence of ionic strength and concentration on molecular diffusion.
• To elucidate intermolecular interactions between proteins and hyaluronic acid.

Main Methods:

• Dynamic Light Scattering (DLS) was employed to measure diffusion coefficients.
• Autocorrelation function (ACF) curve fitting was used for data analysis.
• Molecular Dynamics (MD) simulations were utilized to complement DLS findings.

Main Results:

• In binary systems, diffusion coefficients generally increased with concentration at low ionic strength. At high ionic strength, LYS and OVA diffusion became concentration-independent, while HA diffusion remained concentration-dependent but with a reduced slope.
• In ternary systems, the sum of eigenvalues for OVA/HA was slightly less than the sum of individual binary diffusion coefficients.
• For LYS/HA ternary systems, the sum of eigenvalues was significantly smaller, indicating strong attractive interactions, particularly at low ionic strength.

Conclusions:

• DLS is effective for characterizing diffusion in protein/hyaluronic acid binary and ternary systems.
• Strong attractive interactions between lysozyme and hyaluronic acid were observed, significantly affecting diffusion behavior.
• Ionic strength plays a critical role in modulating diffusion coefficients and intermolecular interactions.