A nanofibrous cell-seeded hydrogel promotes integration in a cartilage gap model

The presence of a defect in mature articular cartilage can lead to degenerative changes of the joint. This is in part caused by the inability of cartilage to regenerate tissue that is capable of spanning a fissure or crack. In this study, we hypothesized that introduction of a biodegradable cell-seeded nanofibrous hydrogel, Puramatrix(), into a cartilage gap would facilitate the generation of a mechanically stable interface. The effects of chondrocyte incorporation within the hydrogel and supplementation with transforming growth factor-beta3 (TGFbeta3), a known regulator of cell growth and differentiation, on cartilage integration were examined mechanically and histologically as a function of cell density and incubation time. When supplemented with TGFbeta3, the cell-seeded hydrogel exhibited abundant matrix generation within the hydrogel and a corresponding increase in maximum push-out stress as compared to all other groups. Furthermore, initial cell seeding density affected interfacial strength in a time-dependent manner. This study suggests that a cell-seeded TGFbeta3-supplemented hydrogel can encourage integration between two opposing pieces of articular cartilage.