Cell-derived polymer/extracellular matrix composite scaffolds for cartilage regeneration, Part 2: construct devitalization and determination of chondroinductive capacity.

This work examined the chondrogenic potential of chondrocyte and mesenchymal stem cell (MSC) coculture generated poly(ɛ-caprolactone) (PCL)/extracellular matrix (ECM) hybrid scaffolds. Five different ratios of chondrocytes and MSCs were cocultured to generate cartilage-like ECM within electrospun fibrous scaffolds for 7, 14, and 21 days. These constructs were then devitalized to isolate the chondrogenic effects of the ECM alone. Devitalization was successful at removing cellular matter from the scaffolds, yet did reduce the amount of matrix present in the scaffolds. Following devitalization, the PCL/ECM scaffolds were then cultured with MSCs in serum-free conditions with or without TGF-β3 treatment for 21 days. TGF-β3 supplemented culture caused an induction of chondrogenesis in each scaffold type, but also somewhat masked the subtle differences of the different ECM coatings. Without TGF-β3, the cartilaginous matrix generated by 1:1 cocultures of chondrocytes to MSCs for 14 days supported similar chondrogenic gene expression patterns of MSCs cultured on scaffolds generated by chondrocytes alone. These scaffold formulations had a positive chondrogenic effect on aggrecan, collagen type II, and collagen II/I expression when compared to PCL controls. This study demonstrates that it is possible to utilize cocultures of chondrocytes and MSCs to coat a polymer scaffold with cartilage-like ECM capable of supporting chondrogenic differentiation of MSCs.