Brillouin-Raman mapping of natural fibers with spectral moment analysis

Fioretto, D.; Caponi, Silvia; Palombo, Francesca

doi:10.1364/boe.10.001469

Cited by 21 publications

(19 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… 12 , by averaging Stokes and anti-Stokes contributions. In particular, we estimated the average frequency shift of each peak through the calculation of the first spectral 43 , 44 , i.e. where the index i spans spectral channels in the range 4–13 GHz and 13–32 GHz for the low-frequency ( ν SOFT ) and high-frequency ( ν HARD ) modes, respectively.…”

Section: Methodsmentioning

confidence: 99%

Mechano-chemistry of human femoral diaphysis revealed by correlative Brillouin–Raman microspectroscopy

Cardinali

Govoni

Caponi

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Brillouin–Raman microspectroscopy is presented as an innovative label-free all-optical investigation approachable to characterize the chemical composition and the mechanical properties of human tissues at micrometric resolution. Brillouin maps unveil mechanical heterogeneities in a human femoral diaphysis, showing a ubiquitous co-existence of hard and soft components, even in the most compact sections. The novel correlative analysis of Brillouin and Raman maps shows that the relative intensity of Brillouin peaks is a good proxy for the fraction of mineralized fibers and that the stiffness (longitudinal elastic modulus) of the hard component is linearly dependent on the hydroxyapatite concentration. For the soft component, a gradient of composition is found, ranging from an abundance of proteins in the more compact, external, bone to abundance of lipids, carotenoids, and heme groups approaching the trabecular, inner, part of the diaphysis. This work unveils the strong potential of correlative mechano-chemical characterization of human tissues at a micrometric resolution for both fundamental and translational research.

show abstract

Section: Methodsmentioning

confidence: 99%

Mechano-chemistry of human femoral diaphysis revealed by correlative Brillouin–Raman microspectroscopy

Cardinali

Govoni

Caponi

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…1(d) would be quite unjustified due to the mixing of homogeneous and heterogeneous mechanisms of broadening. For this reason, we adopt a model-independent estimate of the average frequency shift of each peak through calculation of the first spectral moment [21]…”

Section: Measurements and Data Elaborationmentioning

confidence: 99%

Brillouin micro-spectroscopy of subchondral, trabecular bone and articular cartilage of the human femoral head

Cardinali

Dallari

Govoni

et al. 2019

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

Brillouin micro-spectroscopy is applied for investigating the mechanical properties of bone and cartilage tissues of a human femoral head. Distinctive mechanical properties of the cartilage surface, subchondral and trabecular bone are reported, with marked heterogeneities at both micrometric and millimetric length scales. A ubiquitous soft component is reported for the first time, characterized by a longitudinal modulus of about 4.3 GPa, possibly related to the amorphous phase of the bone. This phase is mixed, at micrometric scales, with a harder component, ascribed to mineralized collagen fibrils, characterized by a longitudinal modulus ranging between 16 and 25 GPa.

show abstract

“…Using 2σR as lateral dimension of the scattering volume and considering as a first approximation that the contributions to the spatial resolution add in quadrature (exact for Gaussian distributions), the lateral acoustic contribution can be found as 2σ E = 2√(σ B ) 2 − (σ R ) 2 . While this value is always utterly negligible for the glass-water interface, for the PET-Glycerol one studied by 1.2 NA objective 2σ E results The present analysis is of significant relevance for a critical assessment of a number of recent works 15,21,[24][25][26][27] , where submicrometric features are discriminated on the basis of Brillouin signature. While the comparison with different optical techniques indicates that the observed elastic modulation is indeed related to structural changes, the measured values of the elastic constant should be considered as spatial averages, whose extent depends on both NA of the optics and on the propagation length of phonons, in turn depending on the investigated material.…”

Section: ))mentioning

confidence: 64%

On the actual spatial resolution of Brillouin Imaging

2020

Self Cite

View full text Add to dashboard Cite

The comprehension of the behavior of complex heterogeneous materials requires the adoption of imaging techniques to analyze spatially resolved properties. With plenty of prospects in biophysical and biomedical fields, Brillouin imaging is an emerging technique able to generate maps with mechanical contrast at microscales. As in any imaging technique a key parameter is the spatial resolution, which depends both on the control of the probe and on the physical mechanism of interaction with the sample. In particular, in Brillouin Spectroscopy the optical scattering volume is only one of the aspects that determine the spatial resolution, the other being the propagation of the detected vibrational modes, an aspect often overlooked in literature. Here, for the first time, by means of theoretical considerations and new experimental data, the importance of the propagating nature of the phonons is clearly disclosed. The unique features of our experimental set-up allow the simultaneous measure of Brillouin and Raman spectra, probing propagating and localized vibrations, respectively. Varying the optical conditions and testing systems with different phonon propagation length provides striking evidence that in Brillouin imaging the phonons contribution to the resolution, inversely related with the optical focusing, can be dominant. Surprisingly, the resolution can even deteriorate when decreasing the scattering volume.

show abstract

Brillouin-Raman mapping of natural fibers with spectral moment analysis

Cited by 21 publications

References 26 publications

Mechano-chemistry of human femoral diaphysis revealed by correlative Brillouin–Raman microspectroscopy

Mechano-chemistry of human femoral diaphysis revealed by correlative Brillouin–Raman microspectroscopy

Brillouin micro-spectroscopy of subchondral, trabecular bone and articular cartilage of the human femoral head

On the actual spatial resolution of Brillouin Imaging

Contact Info

Product

Resources

About