Macroporous PDMSstar–MA:PEG-DA Hydrogels for Osteochondral Regeneration

Osteochondral defects (OCDs) are the result of severe cartilage loss leading to exposure and damage of the subchondral bone. “Materials-guided” tissue engineering is a promising approach to treat these defects, in which a scaffold may mediate the process of OCD regeneration via instructive and tunable physical and chemical properties. For effective healing, an ideal scaffold would spatially direct tissue to mimic the native transition of the osteochondral interface. Conventional poly(ethylene glycol) diacrylate (PEG-DA) hydrogels prepared using aqueous precursor solutions have been commonly studied for tissue engineering purposes, but lack a wide range of desired chemical and physical properties. This study will seek to develop a superior PEG-DA scaffold for OCD repair by (1) integrating methacrylated star polydimethylsiloxane (PDMSstar-MA) to increase bioactivity and osteoinductivity, (2) employing solvent induced phase separation (SIPS) with the use of an organic solvent, and (3) incorporating salt leaching techniques to achieve an interconnected network of pores to allow for cell infiltration. Total macromer concentration (20, 30, and 40 wt%), ratio of PDMSstar-MA to PEG-DA (0:100 and 20:80 wt%), and average salt particle size will be studied with regard to their impact on scaffold morphology, swelling, mechanical properties, and degradation. The tunable nature of these hydrogels could prove especially useful to study material-guided cell behavior for the purpose of osteochondral tissue regeneration