A stratified cell sheet platform coordinating dual osteogenic and chondrogenic differentiation for osteochondral tissue engineering

Stem cell sheets have unique cell-to-cell connections, the ability to enhance and preserve the extracellular matrix (ECM) and cell-ECM interactions, and a scaffold-free nature, which makes them ideal for regenerative medicine. This study aims to explore the potential of stem cell sheets for osteochondral construct fabrication. Mesenchymal stem cells (MSCs) were isolated from rat bone marrow and differentiated into osteogenic and chondrogenic sheets. These differentiated cell sheets were subsequently stacked using a collagen and hyaluronic acid hydrogel between the layers to create multilayered constructs. Histological analysis demonstrated notable tissue formation of a multilayered structure with distinct osteogenic and chondrogenic layers both with and without the hydrogel constructs. Scanning electron microscopy (SEM) confirmed the integrity and content of the sheets. qRT-PCR and immunocytochemistry analysis demonstrated the presence of key related bone and cartilage markers within the differentiated sheets. In conclusion, our data emphasize that stem cell sheet engineering (CSE) holds significant promise for developing 3D, scaffold-free constructs for osteochondral regeneration. The ability to create relatively distinct osteogenic and chondrogenic layers in constructs has an extreme impact on the field of regenerative medicine, leading to a new therapeutic approach and hope for the future of osteochondral defects treatment.