Synchrotron 3D SAXS analysis of bone nanostructure

The complex structure of bone requires a structural description of the material at different hierarchical levels. At the micrometer level, collagen fibril orientation and osteocyte network architecture can be described by different light microscopy methods. However, further investigation of the nanostructure of bone requires high-resolution techniques such as electron microscopy as well as x-ray scattering methods. The basic building blocks at the nanometer level are organic type I collagen fibrils reinforced by nanoparticles of carbonated apatite mineral. Most commonly, these fibrils aggregate into lamellae of about 5 µm width, in both compact and spongy bone. The architecture of the mineral platelets and the collagen fibrils influences the mechanical properties. Models of twisted and rotated plywood motifs have been proposed, although detailed quantitative characterization at length scales comparable to typical tissue unit sizes are still lacking. Here, we describe a scanning small-angle x-ray scatterin...