Chitosan- and Gelatin-Based Composite Granular Hydrogels for Cartilage Tissue Regeneration

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Cartilage regeneration is a significant clinical challenge, with current hydrogel scaffolds lacking sufficient mechanical strength.
• Granular composite hydrogels offer potential solutions due to their injectability and tunable design.

Purpose of the Study:

• To fabricate and characterize heterogeneous composite granular hydrogels for enhanced cartilage regeneration.
• To investigate the mechanical properties and cellular response of these novel hydrogel systems.

Main Methods:

• Developed granular hydrogels using methacrylated chitosan (CHIMA) and gelatin (GelMA) microparticles within a methacrylated alginate (ALMA) matrix.
• Optimized microparticle size and morphology via an oil-emulsion method.
• Evaluated hydrogel swelling, weight loss, mechanical properties (storage modulus), and cell proliferation and chondrogenic differentiation.

Main Results:

• Fabricated CHIMA and GelMA microparticles with optimized sizes (10.8 µm and 115.8 µm, respectively).
• Resulting granular hydrogels exhibited reduced swelling and weight loss compared to controls.
• Increased particle concentration significantly enhanced storage modulus, outperforming traditional ALMA hydrogels.
• A 50:50 CHIMA:GelMA hydrogel formulation supported a 6.6-fold increase in cell number and promoted chondrogenic differentiation of mesenchymal stem cells.

Conclusions:

• Heterogeneous composite granular hydrogels based on CHIMA and GelMA microparticles represent a promising strategy for cartilage tissue engineering.
• These hydrogels demonstrate superior mechanical properties and effectively support cell proliferation and chondrogenic differentiation.
• The developed system addresses key limitations of existing hydrogel scaffolds for cartilage regeneration.