Osteochondral defects are associated with damage of both articular cartilage and underlying subchondral bone. As part of research into repairing these injuries, a sphere-templating technique was applied to fabricate a new degradable, hydrogel-based integrated bi-layered scaffold. One layer of the scaffold was designed with a defined, monodispersed pore size of 38 μm and decorated with hydroxyapatite to promote regrowth of subchondral bone while the second layer had 200 μm pores with covalently attached hyaluronan for articular cartilage regeneration.
The designated cartilage and bone layers of the scaffold were seeded with chondrocytes and primary human mesenchymal stem cells (hMSC), respectively, and were co-cultured in standard medium without soluble growth/differentiation factors over four weeks. The bio-inductive composition of the scaffold supported simultaneous growth of chondrocytes and hMSCs and provided a suitable environment for differentiation of hMSCs to osteoblasts and for retention of chondrocyte phenotype within the designated bone and cartilage layers, respectively.