744 Effect of Heat Degeneration of Collagen Matrix on Bone Strength
Details
Bone is a composite material composed of mineral matrix (mainly hydroxyapatite) and organic matrix (mostly type I collagen) in a microscopic scale. Macroscopic mechanical properties of bone are dependent on the structure and mechanical properties of these microscopic constituents. It has been considered that bone density is a predictor of its strength from a macroscopic perspective, but denaturation of the organic matrix would also lead to a significant loss of bone strength. In this study, heat-treated bone was examined as a collagen denatured model, and then 4-point bending tests and impact tests were conducted to assess the role of the collagen matrix for mechanical properties of bone. As a results of 4-point bending test, the cortical bone specimens heated at over 150℃ failed with a low strain in the elastic region, suggesting a brittle fracture behavior. The elastic modulus of bone was slightly reduced with the heating temperature, whereas the bending strength significantly decreased, especially at 150℃. The results of the impact test shows heat-induced collagen denaturation has great influence on the toughness of bone. These results suggests that not only denatured collagen molecules but also cleaved peptides and/or damaged collagen cross-links play an important role on the mechanical properties of bone.
