Abstract
We studied the micrometric morphology and nanometric structure of the celestite (SrSO4) skeleton of acantharian family Acanthometridae. A body of the skeleton composed of 20 radial spines with four blades was characterized using microfocus X-ray computed tomography. The regular arrangement of three types of spines was clarified with the connection of the blades around the root of each spine. The surface of the spines was covered with a chitin-based organic membrane to prevent dissolution in sea water. On the nanometric scale, the mesocrystalline structure that consists of nanoscale grains having a distorted single-crystal nature was revealed using scanning and transmission electron microscopy, electron diffraction, and Raman spectroscopy. The acantharian skeletons have a crystallographically controlled architecture that is covered with a protective organic membrane.
Multi-modal characterization of collagen fibril orientation in human cortical bone by a combination of quantitative polarized Raman spectroscopy, nanoscale X-ray computed tomography and 360° electron tomography
