Brillouin scattering spectroscopy for studying human anatomy: Towardsin situmechanical characterization of soft tissue

Abstract

Brillouin Light Scattering (BLS) spectroscopy is a label-free method of measuring the GHz-frequency viscoelastic properties. The measured longitudinal modulus is acutely sensitive to the degree of hydration, crosslinking, and temperature, which can be indicative of tissue health. As such, performing in situ measurements on humans is particularly desirable for exploring potential clinical translation, however, is not possible with existing designs which are coupled to bench-top microscopes. Here we introduce a robust fiber coupled hand-held BLS probe and demonstrate its reliability for measuring excised human tissue. We verify its accuracy using confocal BLS microscopy and further show that it is possible to distinguish veins, arteries, nerves and muscles based on their BLS-measured viscoelasticity. This provides a necessary first step towards in situ clinical BLS viscoelasticity studies of human tissue.

Label-free Brillouin endo-microscopy for the quantitative 3D imaging of sub-micrometre biology

“…However, in-vivo endoscopic translation of this technology has been slow, in part due to the large Brillouin frequency shifts stimulated or spontaneously scattered light experiences as it propagates through glass optical fibres. Towards addressing this limitation, recent spontaneous Brillouin spectroscopy techniques have utilised hollow-core fibres 17 or partially-free-space dual-fibre mechanisms 18 to demonstrate single-point and 1D spectral acquisitions, yet full 3D imaging has remained elusive.…”

Brillouin spectroscopy for accurate assessment of morphological and mechanical characteristics in micro-structured samples

“…This technique is based on the interaction of light with the acoustic waves that spontaneously propagate inside the sample to extract information about their mechanical properties: the viscoelastic characterization occurs without any physical contact or labeling, unlike other commonly used approaches [2][3][4][5][6]. This peculiar characteristic made Brillouin spectroscopy a valuable technique to measure the mechanical properties of biological and biomedical samples [7][8][9][10][11][12]. However, the complex and heterogeneous nature of biological samples introduced new challenges on the interpretation of Brillouin spectra, where the mechanical information is highly intertwined with the morphology of the sample [13,14].…”