Wide Angle X-ray Diffraction and Small Angle X-ray scattering Studies on the Effect of Demineralization on Hierarchical Structure of Bone

Abstract

  We investigated that the effect of demineralization on the hierarchical structure of bovine femur by means of simultaneous synchrotron radiation wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) measurement. The azimuthal intensity distributions at the 2θ of (002) WAXD reflection of bones with various degrees of demineralization obtained as a function of demineralization time (t_i) indicate that the orientation of HAp micro-crystals is independent on the mineral fraction. The SAXS diffraction peaks due to the long period between the minerals deposited to the gap region of collagen fibrils were observed in the SAXS profiles for the intact bone and partially demineralized bones (PDBs). The ratio of the SAXS peak intensity of first-order diffraction to that of third-order diffraction was independent on the t_i. The result indicates that the minerals deposited into the gap region of collagen fibril are homogenously demineralized in the 0.5 M EDTA solution. The SAXS profiles in the direction perpendicular to the bone axis suggest that the higher-order structure of bone was not affected by the demineralization up to t_i = 2 h, whereas that was degraded at t_i = 3.5 h.