Cooperative deformation of mineral and collagen in bone at the nanoscale

• DOI: 10.1073/pnas.0604237103
• Publication Date: 2006-11-10T01:48:44Z
• Authors: Himadri S. Gupta; Jong Seto; Wolfgang Wagermaier; Paul Zaslansky; Peter Boesecke; Peter Fratzl
• Keywords: Male; 0301 basic medicine; Minerals; Bone and Bones; Elasticity; 03 medical and health sciences; X-Ray Diffraction; Tensile Strength; Animals; Cattle; Collagen; Stress, Mechanical; Shear Strength

In biomineralized tissues such as bone, the recurring structural motif at supramolecular level is an anisotropic stiff inorganic component reinforcing soft organic matrix. The high toughness and defect tolerance of natural composites believed to arise from these nanometer scale motifs. Specifically, load transfer in bone has been proposed occur by a tensile strains between (mineral apatite) particles via shearing intervening (collagen) layers. This raises question how what extent do mineral fibrils deform concurrently response tissue deformation. Here we show that both nanoparticles enclosing mineralized fibril initially elastically, but different degrees. Using situ testing with combined brilliance synchrotron X-ray diffraction scattering on same sample, tissue, fibrils, take up successively lower levels strain, ratio 12:5:2. maximum strain seen (≈0.15–0.20%) can reach twice fracture calculated for bulk apatite. results are consistent staggered model matrix, exemplifying hierarchical nature We believe this process mechanism fibril–matrix decoupling protecting brittle phase while effectively redistributing energy within tissue.