Brillouin-Raman microspectroscopy for the morpho-mechanical imaging of human lamellar bone.
Martina Alunni CardinaliA Di MicheleM MattarelliS CaponiM GovoniD DallariS BroginiFrancesco MasiaPaola BorriWolfgang LangbeinF PalomboA MorresiD FiorettoPublished in: Journal of the Royal Society, Interface (2022)
Bone has a sophisticated architecture characterized by a hierarchical organization, starting at the sub-micrometre level. Thus, the analysis of the mechanical and structural properties of bone at this scale is essential to understand the relationship between its physiology, physical properties and chemical composition. Here, we unveil the potential of Brillouin-Raman microspectroscopy (BRaMS), an emerging correlative optical approach that can simultaneously assess bone mechanics and chemistry with micrometric resolution. Correlative hyperspectral imaging, performed on a human diaphyseal ring, reveals a complex microarchitecture that is reflected in extremely rich and informative spectra. An innovative method for mechanical properties analysis is proposed, mapping the intermixing of soft and hard tissue areas and revealing the coexistence of regions involved in remodelling processes, nutrient transportation and structural support. The mineralized regions appear elastically inhomogeneous, resembling the pattern of the osteons' lamellae, while Raman and energy-dispersive X-ray images through scanning electron microscopy show an overall uniform distribution of the mineral content, suggesting that other structural factors are responsible for lamellar micromechanical heterogeneity. These results, besides giving an important insight into cortical bone tissue properties, highlight the potential of BRaMS to access the origin of anisotropic mechanical properties, which are almost ubiquitous in other biological tissues.
Keyphrases
- electron microscopy
- high resolution
- bone mineral density
- bone regeneration
- soft tissue
- endothelial cells
- bone loss
- deep learning
- postmenopausal women
- body composition
- mental health
- mass spectrometry
- machine learning
- induced pluripotent stem cells
- computed tomography
- photodynamic therapy
- high speed
- density functional theory
- magnetic resonance
- fluorescence imaging