Injectable MSC Spheroid and Microgel Granular Composites for Engineering Tissue.

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Cell Biology

Background:

• Direct cell-cell interactions are crucial for cell differentiation and function, but challenging to integrate into 3D tissue constructs.
• Existing tissue engineering methods often lack sufficient cell-cell contact, hindering processes like chondrogenesis in cartilage repair.

Purpose of the Study:

• To develop an injectable granular composite system for tissue engineering that facilitates cell-cell interactions.
• To engineer functional cartilage tissue with native-like mechanical properties and integration capacity.

Main Methods:

• Combining mesenchymal stromal cell (MSC) spheroids with hyaluronic acid microgels to form injectable granular composites.
• Utilizing light-induced crosslinking for initial stabilization and analyzing spheroid-to-microgel ratios for optimal mechanical support and growth.
• Conducting long-term chondrogenic cultures and evaluating matrix deposition, mechanical properties, and in vivo integration.

Main Results:

• The developed granular composites are injectable and allow for spheroid fusion and growth, promoting cell-cell signaling.
• Engineered cartilage tissues exhibited extensive matrix deposition and mechanical properties comparable to native cartilage.
• The engineered cartilage demonstrated successful integration with native tissue.

Conclusions:

• Injectable granular composites offer a novel strategy for tissue engineering by combining the benefits of cell-cell interactions via spheroids with hydrogel-based mechanical stabilization.
• This approach successfully engineers functional cartilage tissue, addressing limitations of previous methods by promoting chondrogenesis through enhanced cell-cell contact.