Bone graft substitutes are used in bone tissue engineering, orthopedics, and dentistry to help bone repair. The sterility and pyrogenicity of the bone grafts before clinical use are considered part of the regulatory requirements, however sterilization of biomaterials is challenging due to the physicochemical changes resulting from the localized increase in gamma dose during irradiation. The effects of gamma radiation dose on the biological behavior of synthetic bone grafts have not been extensively investigated. The present study aimed to evaluate the effects of gamma radiation sterilization doses on OsvehOss synthetic bone grafts via chemical, mechanical, and in vitro biological examinations. XRD analysis and compression test were carried out to evaluate the chemical and mechanical changes of synthetic bone grafts induced by the highest gamma radiation dose applied in this study. Human osteosarcoma MG-63 cells were used to assay their osteogenic response while grown on a biphasic bone graft substitute. Cell attachment and proliferation were confirmed via scanning electron microscopy on days 3, 7, and 14 of culture. Alkaline phosphatase (ALP) activity was determined to assess osteogenesis. Alizarin red S (ARS) staining was also used to identify calcium deposition in osteocytes developed after differentiation of MG-63 cells. Our results illustrated that gamma irradiation did not cause dose-dependent changes in chemical and mechanical properties of OsvehOss BCP (Biphasic Calcium Phosphate) bone grafts when the doses increased up to 50 kGy. Furthermore, OsvehOss BCP samples demonstrated high osteoconductivity in all irradiation treatment groups. ALP and ARS analyses also indicated that the application of irradiation doses up to 50 kGy for sterilization of OsvehOss BCP grafts had no significant effects on osteogenesis and calcium deposition in osteoblast cells cultured on grafts. In conclusion, OsvehOss biomaterials can be sterilized safely for biomedical applications.

Keywords