Double-Network Hydrogel Based on Methacrylated Chitosan/Hyaluronic Acid Coacervate for Enhanced Wet-Tissue Adhesion

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surgical Adhesives

Background:

• Developing effective wet tissue adhesives is difficult due to water interference and uneven tissue surfaces.
• Polyelectrolyte coacervates show promise for wet adhesion but have limited cohesion for practical use.

Purpose of the Study:

• To create a robust wet tissue bioadhesive using coacervates of methacrylated chitosan (CSMA) and hyaluronic acid (HA).
• To evaluate the adhesive properties and stability of the developed CSMA-HA hydrogel under physiological conditions.

Main Methods:

• Formation of homogeneous and transparent coacervates from low-molecular-weight CSMA and HA.
• Photo-cross-linking of coacervates in situ to form a double-network hydrogel on wet tissue surfaces.
• Assessment of adhesion strength via bursting pressure tests and stability after PBS immersion.

Main Results:

• CSMA-HA coacervates exhibited high solid content (~18.0%) and fluidity (~10^5 mPa·s) with tunable mechanical properties.
• The in situ photo-cross-linked CSMA-HA hydrogel achieved a robust bursting pressure of 374 mmHg.
• Adhesion strength increased to ~623 mmHg after 24 h PBS immersion, attributed to dynamic bond reorganization and low swelling.

Conclusions:

• CSMA-HA coacervates provide a transformative platform for developing advanced wet tissue adhesives.
• The developed hydrogel demonstrates excellent stability under physiological conditions and superior wet adhesion capabilities.
• This bioadhesive offers improved cohesion and durable performance, addressing limitations of current wet adhesion technologies.