Hyaluronan size and concentration: Effect on key biophysical and biochemical features

Area of Science:

• Biochemistry
• Materials Science
• Rheology

Background:

• Hyaluronan (HA) is crucial in formulations, but its properties vary with molecular weight (MW) and concentration (c).
• Understanding these relationships is key for optimizing HA-based products.

Purpose of the Study:

• To systematically investigate the impact of a wide range of HA MW and concentrations on formulation rheology, stability, and biological activity.
• To develop mathematical correlations for predicting HA formulation behavior.

Main Methods:

• Characterization of nine pharmaceutical-grade HA samples (60-2500 kDa) using Size Exclusion Chromatography-Triple Detector Array (SEC-TDA).
• Testing of HA aqueous solutions (0.1-32 g/L) for dynamic viscosity (η).
• Assessment of HA effects on human dermal fibroblasts, collagen-I, elastin, and hyaluronan synthase-1 expression.

Main Results:

• Established mathematical correlations for zero-shear viscosity, critical shear rate, and shear-thinning extent based on HA MW and c.
• Identified dilute, semi-dilute, and a new concentrated rheological regimes for HA solutions.
• Found lower MW HAs (60-90 kDa) stable to sterilization and hydrolysis, while higher MW HAs (220-2500 kDa) depolymerized.
• Demonstrated comparable support for fibroblast growth, wound healing, and gene expression across tested HA sizes.

Conclusions:

• HA MW and concentration significantly influence rheological and stability properties of HA formulations.
• Mathematical models are provided for optimizing HA formulations.
• HA size does not critically affect fibroblast behavior or wound healing support in vitro.