Cartilage-Derived Progenitor Cell-Laden Injectable Hydrogel-An Approach for Cartilage Tissue Regeneration

Cartilage-derived progenitor cells (CPCs) with the capability of self-renewal and multilineage differentiation have been identified as a suitable cell source for cartilage tissue regeneration. Despite decades of development in cell-delivery techniques, improved approaches are still required to maintain cell viability, provide a supportive environment, and implement appropriate cues to guide cartilage regeneration. This research work develops an injectable in situ gelation system as a cell carrier for CPCs to overcome cell-delivery drawbacks. The hydrogel was fabricated through a thiol-ene Michael addition reaction by cross-linking thiol-functionalized hyaluronic acid and hyperbranched poly(ethylene glycol) multi-acrylate macromer. The sol-gel transition, mechanical properties, microstructure, and degradation profile of the hydrogels were evaluated to ensure physical support, cell migration, and nutrient exchange within the system. Encapsulated CPCs maintained a high level of cell viability and proliferation property. Reverse transcription-quantitative real-time polymerase chain reaction confirmed that the extracellular matrix (ECM) secretion was enhanced under chondrogenic conditions. Moreover, the downregulated inflammation gene expression indicated the anti-inflammation ability of encapsulated CPCs. The study demonstrates that this rapid in situ forming hydrogel has excellent potential as a CPC delivery carrier by accelerating ECM production and retaining the phenotype and function of encapsulated CPCs.