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Reduction of fibrillar strain-rate sensitivity in steroid-induced osteoporosis linked to changes in mineralized fibrillar nanostructure

DOI: 10.1016/j.bone.2019.115111 DOI Help

Authors: L. Xi (Beijing Institute of Technology; Queen Mary University of London) , P. De Falco (Queen Mary University of London; Max Planck Institute of Colloids and Interfaces) , E. Barbieri (Queen Mary University of London; Yokohama Institute for Earth Sciences) , A. Karunaratne (University of Moratuwa) , L. Bentley (MRC Harwell) , C. T. Esapa (MRC Harwell; University of Oxford) , G. R. Davis (Queen Mary University of London) , N. J. Terrill (Diamond Light Source) , R. D. Cox (MRC Harwell) , N. M. Pugno (University of Trento; Queen Mary University of London; Edoardo Amaldi Foundation) , R. V. Thakker (University of Oxford) , R. Weinkamer (Max Planck Institute of Colloids and Interfaces) , W. W. Wu (Beijing Institute of Technology) , D. N. Fang (Beijing Institute of Technology; Peking University) , H. S. Gupta (Queen Mary University of London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Bone

State: Published (Approved)
Published: November 2019
Diamond Proposal Number(s): 9893 , 11806 , 12483

Abstract: As bone is used in a dynamic mechanical environment, understanding the structural origins of its time-dependent mechanical behaviour – and the alterations in metabolic bone disease – is of interest. However, at the scale of the mineralized fibrillar matrix (nanometre-level), the nature of the strain-rate dependent mechanics is incompletely understood. Here, we investigate the fibrillar- and mineral-deformation behaviour in a murine model of Cushing’s syndrome, used to understand steroid induced osteoporosis, using synchrotron small- and wide-angle scattering/diffraction combined with in situ tensile testing at three strain rates ranging from 10-4 to 10-1 s-1. We find that the effective fibril- and mineral-modulus and fibrillar-reorientation show no significant increase with strain-rate in osteoporotic bone, but increase significantly in normal (wild-type) bone. By applying a fibril-lamellar two-level structural model of bone matrix deformation to fit the results, we obtain indications that altered collagen-mineral interactions at the nanoscale – along with altered fibrillar orientation distributions – may be the underlying reason for this altered strain-rate sensitivity. Our results suggest that an altered strain-rate sensitivity of the bone matrix in osteoporosis may be one of the contributing factors to reduced mechanical competence in such metabolic bone disorders, and that increasing this sensitivity may improve biomechanical performance.

Journal Keywords: Glucocorticoid induced osteoporosis; Synchrotron X-ray nanomechanical imaging; Nanoscale deformation mechanisms; Multiscale; mechanical modelling

Diamond Keywords: Bone

Subject Areas: Biology and Bio-materials

Instruments: I22-Small angle scattering & Diffraction

Added On: 18/11/2019 14:58

Discipline Tags:

Osteoporosis Non-Communicable Diseases Health & Wellbeing Soft condensed matter physics Life Sciences & Biotech

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS) Wide Angle X-ray Scattering (WAXS)