Radioprotection and cross-linking of allograft bone in the presence of vitamin E.

Abstract

Bone allografts are the preferred method for bone augmentation in over 500,000 orthopedic surgical procedures in the US. Sterilization by ionizing radiation is the most effective method of minimizing the bioburden of bone allografts; however, radiation causes chain scission of collagen, resulting in the reduction of the allografts' mechanical strength. In this study, we doped bone allografts with vitamin E as radioprotectant using a novel two-step process to protect the collagen architecture against radiation damage and to preserve the mechanical strength of the construct. In addition, combining the radioprotectant with a cross-linking agent further minimized collagen degradation and further preserved the mechanical strength of the allografts. Both vitamin E and combined vitamin E/genipin-treated allograft were less cytotoxic to both osteoblasts and osteoclasts when compared to irradiated-only allografts. Host bone-allograft unionization was faster in a rat calvaria defect model with vitamin E-treated and combined vitamin E and genipin-treated allograft when compare to irradiated-only allografts. This method can enable the efficient and uniform radioprotective treatment of bone allograft of desired shapes for sterilization with improved mechanical strength and biointegration.