γ-Irradiation sterilized bone strengthened and toughened by ribose pre-treatment

• Irradiation sterilization weakens and embrittles cortical bone.
• Irradiation sterilization damage decreases the bone collagen network connectivity.
• A pre-treatment containing ribose protects the bone collagen network connectivity.
• Ribose pre-treatment partially protects irradiated bone strength, ductility, and toughness.

ObjectiveThis study tested the hypothesis that a ribose-based pre-treatment would protect the strength, ductility and toughness of γ-irradiation sterilized cortical bone.MethodsExperiment 1: The effects of ribose pre-treatment (1.8 M in PBS at 60 °C for 24 h) prior to 33kGy of irradiation on strength, ductility and toughness (beams in three-point bending) and fracture toughness (J-integral at instability in single edge notched (bending)) were tested against matched non-irradiated and irradiated controls from bovine tibiae. Experiment 2: Three-point bending tests were conducted using beams from human femora (males, 59–67 years). Bone collagen thermal stability and network connectivity were examined using hydrothermal isometric tension testing.ResultsRibose pre-treatment protected the strength, ductility and toughness of irradiation sterilized bovine and human specimens to differing degrees. Their ultimate strength was not detectably different from non-irradiated control levels; toughness in bovine and human specimens was protected by 57 and 76%, respectively. Untreated human bone was less affected by irradiation and ribose pre-treatment was more effective in human bone than bovine bone.ConclusionsThis paper presents the first proof-of-principle that irradiation-sterilized bone with improved mechanical properties can be produced through the application of a ribose pre-irradiation treatment, which provides a more stable and connected collagen network than found in conventionally irradiated controls.

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