Small-angle x-ray scattering (SAXS) can provide information on mean size, predominant orientation and typical shape of mineral crystals in bone. In this paper, recent developments of this technique for application in bone research are reviewed. Then the structure of the collagen/mineral composite in bone, as determined by SAXS, is compared for a number of species. The thickness of the mineral crystals was found to increase with age up to a value around 3 to 4 nanometers in adult animals, depending on the species. The SAXS results also suggest the existence of needle-shaped mineral crystals in mouse or rat bone and more plate-shaped crystals in other tissues like adult human bone or mineralized turkey leg tendon.
Keywords: Collagen; hydroxyapatite; biomineralization; calcified tissue; diffraction