Enzymatically Cross-Linked Poly(γ-glutamic acid) Hydrogel with Enhanced Tissue Adhesive Property

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Enzymatic cross-linking of polymer-catechol conjugates is key for injectable hydrogels.
• Optimizing tissue adhesive properties requires understanding complex variables.
• Poly(γ-glutamic acid)-dopamine (PGADA) conjugates offer potential for advanced biomaterials.

Purpose of the Study:

• To synthesize PGADA conjugates and fabricate *in situ*-forming hydrogels.
• To optimize PGADA hydrogel tissue adhesive properties by investigating key factors.
• To evaluate the gelation, mechanical strength, and tissue adhesion of PGADA hydrogels.

Main Methods:

• Synthesis of poly(γ-glutamic acid)-dopamine (PGADA) conjugates.
• Fabrication of *in situ* hydrogels via enzymatic cross-linking using horseradish peroxidase (HRP) and H₂O₂.
• Characterization of gelation behavior and mechanical strength using rheometry and viscometry.
• Evaluation of *in vitro* and *ex vivo* tissue adhesion strength.

Main Results:

• Investigated the impact of polymer concentration, catechol substitution degree (DS), HRP concentration, and H₂O₂ content on hydrogel properties.
• Characterized the gelation kinetics and mechanical performance of the PGADA hydrogels.
• Assessed the *in vitro* and *ex vivo* tissue adhesive capabilities of the optimized hydrogels.

Conclusions:

• PGADA hydrogels fabricated via enzymatic cross-linking show promise as injectable tissue adhesives.
• Optimization of formulation parameters is crucial for enhancing hydrogel performance.
• Further studies can explore PGADA hydrogels for various biomedical applications requiring tissue adhesion.