Effects of Gamma Irradiation and Supercritical Carbon Dioxide Sterilization on Methacrylated Gelatin/Hyaluronan Hydrogels

This study evaluated how terminal sterilization methods (gamma irradiation and supercritical carbon dioxide (scCO₂)) affect the physicochemical, mechanical, and biological performance of methacrylated gelatin (GelMA), methacrylated hyaluronan (HAMA), and hybrid GelMA/HAMA hydrogels intended for bone regeneration. The authors showed that hydrogel composition strongly influenced stiffness, degradation behavior, and osteogenic support of human bone marrow–derived mesenchymal stem cells (hBMSC). Gamma irradiation reduced elastic modulus, particularly in HA-containing gels, but preserved or enhanced osteogenic cell responses, whereas scCO₂ sterilization significantly impaired cell proliferation and differentiation. Overall, gamma-irradiated GelMA/HAMA hydrogels were identified as the most promising scaffold formulation for bone substitute applications.