Bone chemical structure response to mechanical stress studied by high pressure Raman spectroscopy
O de Carmejane1, M D Morris, M K Davis
1Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
Calcified Tissue International
|March 3, 2005
Summary
Bone
Area of Science:
- Biomaterials Science
- Biophysics
- Skeletal Biology
Background:
- Bone's biomechanical properties are understood at many structural levels.
- However, its response to loading at ultrastructural and crystal lattice levels remains largely unknown.
Purpose of the Study:
- To investigate the response of murine cortical bone to hydrostatic compression.
- To analyze the vibrational frequency changes in mineral and matrix components under pressure.
Main Methods:
- Utilized high-pressure Raman microspectroscopy to apply hydrostatic compression to bone samples.
- Measured the rate of change in vibrational frequencies of mineral (phosphate, carbonate) and matrix (protein) components during loading and unloading.
- Compared responses between proteinated and deproteinated bone.
Main Results:
- All mineral species exhibited shifts to higher wave numbers with increasing pressure.
- Carbonate showed less frequency change than phosphate, attributed to ionic movement within the unit cell.
- Phosphate deformation involved both ionic movement and distortion.
- Organic species displayed greater vibrational frequency changes than mineral species, indicating alterations in protein secondary structures.
- Loading and unloading responses were similar, suggesting reversibility due to water's inability to be permanently expelled from the lattice.
Conclusions:
- Individual mineral and matrix constituents of bone respond differently to mechanical stress.
- High-pressure Raman microspectroscopy provides insights into bone's response at the crystal lattice level.
- Findings highlight the complex interplay between bone's mineral and organic components under pressure.
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