Lu, StevenLam, JohnnyTrachtenberg, Jordan E.Lee, Esther J.Seyednejad, Hajarvan den Beucken, Jeroen J.J.P.Tabata, YasuhikoWong, Mark E.Jansen, John A.Mikos, Antonios G.Kasper, F. Kurtis2017-08-042017-08-042014Lu, Steven, Lam, Johnny, Trachtenberg, Jordan E., et al.. "Dual growth factor delivery from bilayered, biodegradable hydrogel composites for spatially-guided osteochondral tissue repair." <i>Biomaterials,</i> 35, no. 31 (2014) Elsevier: 8829-8839. https://doi.org/10.1016/j.biomaterials.2014.07.006.https://hdl.handle.net/1911/96578The present work investigated the use of biodegradable hydrogel composite scaffolds, based on the macromer oligo(poly(ethylene glycol) fumarate) (OPF), to deliver growth factors for the repair of osteochondral tissue in a rabbit model. In particular, bilayered OPF composites were used to mimic the structural layers of the osteochondral unit, and insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) were loaded into gelatin microparticles and embedded within the OPF hydrogel matrix in a spatially controlled manner. Three different scaffold formulations were implanted in a medial femoral condyle osteochondral defect: 1) IGF-1 in the chondral layer, 2) BMP-2 in the subchondral layer, and 3) IGF-1 and BMP-2 in their respective separate layers. The quantity and quality of osteochondral repair was evaluated at 6 and 12 weeks with histological scoring and micro-computed tomography (micro-CT). While histological scoring results at 6 weeks showed no differences between experimental groups, micro-CT analysis revealed that the delivery of BMP-2 alone increased the number of bony trabecular islets formed, an indication of early bone formation, over that of IGF-1 delivery alone. At 12 weeks post-implantation, minimal differences were detected between the three groups for cartilage repair. However, the dual delivery of IGF-1 and BMP-2 had a higher proportion of subchondral bone repair, greater bone growth at the defect margins, and lower bone specific surface than the single delivery of IGF-1. These results suggest that the delivery of BMP-2 enhances subchondral bone formation and that, while the dual delivery of IGF-1 and BMP-2 in separate layers does not improve cartilage repair under the conditions studied, they may synergistically enhance the degree of subchondral bone formation. Overall, bilayered OPF hydrogel composites demonstrate potential as spatially-guided, multiple growth factor release vehicles for osteochondral tissue repair.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier.Journal articleBone morphogenetic protein-2Cartilage repairInsulin-like growth factor-1Rabbit modelSubchondral bonespatially-guided_osteochondral_tissue_repairhttps://doi.org/10.1016/j.biomaterials.2014.07.006