Rheology and Gelation of Hyaluronic Acid/Chitosan Coacervates

Area of Science:

• Biomaterials Science
• Polymer Physics
• Rheology

Background:

• Hyaluronic acid (HA) and chitosan (CHI) are biocompatible biopolyelectrolytes with significant interest in medical and polymer physics applications.
• Their semi-flexible nature and polyelectrolyte properties make them suitable for advanced material development.

Purpose of the Study:

• To investigate the influence of molecular weight on the linear viscoelasticity of hyaluronic acid/chitosan (HA/CHI) coacervates.
• To evaluate the impact of catechol conjugation on the mechanical properties of HA/CHI coacervates.

Main Methods:

• Rheology experiments were employed to measure the linear viscoelastic properties of HA/CHI coacervates.
• Comparison of mechanical moduli between native coacervates, individual polymer gels, and catechol-conjugated coacervates.

Main Results:

• The viscoelasticity of HA/CHI coacervates was found to be highly dependent on the molecular weight of the constituent polymers.
• Coacervates exhibited significantly higher moduli compared to individual HA and CHI physical gels.
• Catechol-conjugated HA/CHI coacervates demonstrated a 1.5-fold increase in moduli due to the formation of di-DOPA crosslinks.

Conclusions:

• The molecular weight of polymers is a critical factor in determining the mechanical properties of HA/CHI coacervates.
• Catechol conjugation effectively transforms coacervates into chemical gels with enhanced mechanical strength.
• These findings position HA/CHI coacervates as promising candidates for injectable tissue scaffolds and medical adhesives.