“Multipurpose” Gelatin-Chitosan-Based Injectable Gel Platform for Stem Cell Expansion, Delivery, and Tissue Regeneration

Microsphere-based 3D platforms offer a significant advantage for cell expansion, targeted cell/biomolecule delivery, and transplantation, as microspheres provide a biomimetic microenvironment that enhances cell survival, proliferation, and ensures better retention and functional integration. Herein, we have fabricated gelatin-chitosan-based microspheres that serve as a "dual-delivery platform" for cells and growth factor, and can also be used as a 3D culture platform for cell expansion. The isolated mesenchymal stem cells were loaded and cultured on the surface of these microspheres simultaneously with a growth factor, followed by second layer coating, a strategy to protect the loaded cells during transplantation. Microspheres serve as a delivery system to accomplish the sustained long-term release of growth factors to mediate the differentiation of stem cells into osteogenic, adipogenic, and chondrogenic lineages. These 3D microspheres can also be used for cell expansion and harvesting from the surface of microspheres for the intended application.