Bioapatite in shark centra studied by wide-angle and by small-angle X-ray scattering

J. S. Park, J. D. Almer, K. C. James, L. J. Natanson, S. R. Stock*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Members of subclass Elasmobranchii possess cartilage skeletons; the centra of many species are mineralized with a bioapatite, but virtually nothing is known about the mineral's organization. This study employed high-energy, small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS, i.e. X-ray diffraction) to investigate the bioapatite crystallography within blocks cut from centra of four species (two carcharhiniform families, one lamniform family and 1-ID of the Advanced Photon Source). All species' crystallographic quantities closely matched and indicated a bioapatite closely related to that in bone. The centra's lattice parameters a and c were somewhat smaller and somewhat larger, respectively, than in bone. Nanocrystallite sizes (WAXS peak widths) in shark centra were larger than typical of bone, and little microstrain was observed. Compared with bone, shark centra exhibited SAXS D-period peaks with larger D magnitudes, and D-period arcs with narrower azimuthal widths. The shark mineral phase, therefore, is closely related to that in bone but does possess real differences which probably affect mechanical property and which are worth further study.

Original languageEnglish (US)
Article number20220373
JournalJournal of the Royal Society Interface
Issue number194
StatePublished - Sep 21 2022


  • X-ray diffraction
  • centrum
  • mineralized tissue
  • shark
  • small-angle X-ray scattering
  • wide-angle X-ray scattering

ASJC Scopus subject areas

  • Bioengineering
  • Biophysics
  • Biochemistry
  • Biotechnology
  • Biomedical Engineering
  • Biomaterials


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