Glucose stabilizes collagen sterilized with gamma irradiation

Gamma irradiation sterilization (gamma-irradiation) fragments and denatures collagen, drastically decreasing critical physical properties. Our goal was to maintain strength and stability of gamma-irradiated collagen by adding glucose, which in theory can initiate crosslink formation in collagen during exposure to gamma-irradiation. Collagen films prepared with and without glucose were gamma-irradiated with a standard dose of 2.5 Mrad. Relative amounts of crosslinking and denaturation were approximated based on solubility and the mechanical properties of the films after hydration, heat denaturation, or incubation in enzymes (collagenase and trypsin). After exposure to gamma-irradiation, collagen films containing glucose had significantly higher mechanical properties, greater resistance to enzymatic degradation, and decreased solubility compared with control films. The entire experiment was repeated with a second set of films that were exposed first to ultraviolet irradiation (254 nm) to provide higher initial strength and then gamma-irradiated. Again, films containing glucose had significantly greater mechanical properties and resistance to enzymatic degradation compared with controls. Gel electrophoresis showed that glucose did not prevent peptide fragmentation; therefore, the higher strength and stability in glucose-incorporated films may be due to glucose-derived crosslinks. The results of this study suggest that glucose may be a useful additive to stabilize collagenous materials or tissues sterilized by gamma-irradiation.