A study of the adaptation of the mechanical properties of bone material using Raman spectroscopy.
Doctoral thesis, UCL (University College London).
Bone is a composite material comprising an organic collagen scaffold surrounded by mineral platelets. The weight ratio of mineral to collagen is not constant, and hence the mechanical properties of the material can vary. In this thesis, the analytical technique Raman spectroscopy (which uses inelastically scattered photons to probe chemical composition) is used to explore the hypothesis that the mechanical properties of bone material are adapted in differently loaded regions by a subtle tuning of the collagen chemistry, which controls the mineral to collagen ratio. The question is first approached by looking at Raman spectra of a range of bony materials which are adapted to different functions. Bone material composition in different loading environments within individual bone organs is then examined, and finally, collagen Raman band profiles from a range of bony material are examined to search for variations which would signify differences in collagen chemistry. The results of the experiments show that for the functionally adapted bony materials a correlation exists between the Raman spectra and mechanical properties. Raman data from further experiments show that there are anatomical regions near the ends of long bones where the mineral to collagen ratio is lower than average (that this may be another adaptation of mineral/collagen ratio to function is discussed). Finally, analyses of Raman band profiles are presented which show that there are differences in the collagen chemistry of the various functionally adapted bony materials. The work furthers our understanding of the relationship between the mechanical properties of bone material and its Raman spectrum, a relationship which is of great importance if Raman spectroscopy is to be developed as an in vivo technique. Understanding the regional variations in mineral to collagen ratio will be vital if Raman spectroscopy is to be utilised to measure the mechanical integrity of whole bone organs. The elucidation of the band profile differences may provide a therapeutic target for the management of bone conditions i.e. enabling the control of the mechanical properties of bone; further research is required to determine what specific aspect of the collagen chemistry they represent, and to establish the causal relationship from the spectra to mechanical properties.
|Title:||A study of the adaptation of the mechanical properties of bone material using Raman spectroscopy|
|Open access status:||An open access version is available from UCL Discovery|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Medical Sciences > Surgery and Interventional Science (Division of) > Institute of Orthopaedics and Musculoskeletal Science|
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