Codelivery of Synovium-Derived Mesenchymal Stem Cells and TGF-β by a Hybrid Scaffold for Cartilage Regeneration.

Synovium-derived mesenchymal stem cells (SMSCs) are attractive tissue-specific cells for cartilage regeneration because of their easy availability, higher chondrogenic potential, and joint specificity. In the present study, we established a hybrid scaffold to codeliver SMSCs and transforming growth factor beta (TGF-β), which can integrate the scaffolds, the growth factor, and the autogenous cells within rabbit cartilage defects. A chitosan hydrogel and a decellularized bone matrix were used to fabricate the gel-solid duplex phase biomaterials, which were proven to retain more cells, promote tissue integration, and provide mechanical support. In vitro experiments demonstrated that this hybrid scaffold could release TGF-β in a controlled biphasic pattern, which can promote cell proliferation and chondrogenic differentiation of loaded rabbit SMSCs. For in vivo experiments, we filled cartilage defects with the hybrid materials, delivering autogenous SMSCs and TGF-β simultaneously via chitosan's sol-gel transition. Histological analysis, magnetic resonance imaging, and nanoindentation assessment indicated superior cartilage regeneration using this codelivery system compared with that from routine microfracture or control delivery scaffolds. Beyond cartilage regeneration, the easy preparation, favorable biophysical properties, and controlled release ability make this codelivery system applicable to transport other tissue-specific cells or biofactors for tissue engineering.