• Wittig, Nina Kølln
• Birkedal, Henrik
• Palle, Jonas

Abstract

Bone has a complex hierarchical structure with structural motifs ranging from the nm-mm scale, giving rise to the unique mechanical and biological properties of bone. Many other biological materials present such hierarchical structures, which are very challenging to unravel. While the structure of human bone is well characterized down to the microscopic scale, the bone structure at the sub-100 µm is still debated with many structural and medical questions remaining unanswered. Studying this nanostructured hierarchical material at the nanoscale is challenging due to its complex 3D structure. <br/>One route to study such materials is X-ray powder diffraction computed tomography (XRD-CT) that reveals the 3D distribution of crystalline phases and X-ray fluorescence computed tomography (XRF-CT) that provides element distributions. <br/>We will present how we have used this technique at beamline P06, DESY, to map spatio/temporal variations in the biomineral across an osteon of human bone with 400 nm voxel size1. This allowed us to show that the microstructural properties of bone mineral is non-homogeneous and highly dependent on the time point at which it was laid down. <br/>Through further development of combined XRD-CT and XRF-CT, we have increased the 3D resolution of the technique below 120 nm opening the path for studying the next structural regime in bone2. <br/>With upgraded synchrotron sources, fast scanning motors, and high quality sample stages, the scan time of scanning XRD and XRF could decrease significantly allowing for probing larger volumes and multiple samples. This would enable new possibilities for unravelling the structure of hierarchical materials, both biological and synthetic. Γ <br/>1. Wittig, N. K.; Palle, J.; Østergaard, M.; Frølich, S.; Birkbak, M. E.; Spiers, K.; Garrevoet, J.; Birkedal, H., Bone Biomineral Properties Vary across Human Osteonal Bone. ACS Nano 2019, 13, 12949-12956.<br/>2. Palle, J.; Wittig, N. K.; Kubec, A.; Niese, S.; Rosenthal, M.; Burghammer, M.; Grünewald, T. A.; Birkedal, H., Nanobeam X-ray fluorescence and diffraction computed tomography on human bone with a resolution better than 120 nm. J. Struct. Biol. 2020, 212, 107631.<br/>

Topics

• impedance spectroscopy
• mineral
• x-ray diffraction
• crystalline phase
• tomography
• biological material
• X-ray fluorescence spectroscopy