Figure 1.

Study design to evaluate the iPS-MP chondrogenesis. A) IPSCs were differentiated down the mesenchymal lineage into iPS-MPs prior to use in this study. B) In pellet culture, iPS-MPs were cultured with chondrogenic media containing no growth factor, TGFβ3 (10 ng ml⁻¹), BMP2 (100 ng ml⁻¹), or TGFβ3 (10 ng ml⁻¹) and BMP2 (100 ng ml⁻¹) and chondrogenesis assessed at day 21 by histology, IHC, and biochemical analysis. C) In 3D culture, iPS-MPs were photoencapsulated in a cartilage-mimetic hydrogel made from multi-arm PEG norbornene macromers, PEG dithiol crosslinkers, and ECM analogs of thiolated-chondroitin sulfate and CRGDS. The iPS-MP-laden hydrogels were cultured in chondrogenic media containing no growth factor, TGFβ3 (2.5 ng ml⁻¹), BMP2 (25 ng ml⁻¹), or TGFβ3 (2.5 ng ml⁻¹) and BMP2 (25 ng ml⁻¹) under free swelling culture or under a dynamic loading protocol. The latter consisted of one week free swelling followed by intermittent dynamic compressive loading for one hour per day. At day 21, iPS-MP differentiation was analyzed via qPCR, IHC and quantitative IHC.