An osteochondral defect is a joint injury characterized by the loss of cartilage along with a thin layer of bone beneath it. The cause of this condition is attributed to a number of factors, including repetitive trauma within the joint, metabolic disorders, and genetic predisposition to diseases such as osteoarthritis. Current treatments are partially successful in returning function, but more effective methods are needed for a longer lasting result and better osseointegration of grafts. We hypothesized that a collagen hydrogel synthesized with inorganic Poly(dimethyl siloxane) star-methacrylate (PDMS*-MA) and Poly(ethylene glycol)-diacrylate (PEG-DA) would promote an increased osteogenic phenotype of encapsulated human mesenchymal stem cells (hMSCs). Specifically, this osteogenic hydrogel (CPP* hydrogel) was created as an interpenetrating polymer network composed of a collagen hydrogel soaked with monomers of PEG-DA and PDMS*-MA. The CPP* hydrogel was shown to have superior mechanical properties than typical collagen hydrogels while maintaining an appropriate swelling ratio to support cell culture. Confocal imaging of the CPP* hydrogels revealed that the encapsulated hMSCs were able to survive the hydrogel formulation steps and assume a morphology characteristic of osteoblasts
