Parametric handheld optical probe (HOPE) for biological tissue characterization in the near-infrared spectral range

Davidov, Daniel; Shemesh, David; Einstein, Ofira; Abookasis, David

doi:10.1016/j.optcom.2021.127076

Cited by 2 publications

(1 citation statement)

References 57 publications

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“…The electromagnetic spectrum from terahertz to mid-infrared region is vital to living organisms since the collective vibrations of most biomacromolecules (e.g., DNA and protein) fall within this frequency range, where many significant physiological phenomena and biomedical applications have been reported ( Barone et al, 2005 ; Kitagawa et al, 2006 ; Rodrigo et al, 2015 ; Cheon et al, 2016 ; Turker-Kaya and Huck, 2017 ; Mittal et al, 2018 ; Zhu et al, 2021 ; Zhang et al, 2021 ; Li et al, 2021 ; Li et al, 2022 ; Sun et al, 2022 ). In addition, the spectra of the optical constant (refractive index and extinction coefficient), and the dielectric constant (real and imaginary parts of the permittivity) of all biomaterials contain the inherent information of their internal molecules, atoms and chemical bonds, and hence could be utilized as the functional biosignatures ( Pethig and Kell, 1987 ; Parthasarathy et al, 2005 ; Davidov et al, 2021 ). A recent experimental study finds that the frog sciatic nerve shows distinct refractive indexes measured at different spots in the terahertz to mid-infrared band, suggesting that the myelinated nerve fiber might act as a decent dielectric waveguide ( Liu et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Dielectric dispersion characteristics of the phospholipid bilayer with subnanometer resolution from terahertz to mid-infrared

Zhang¹,

Li²,

Xiang³

et al. 2022

Front. Bioeng. Biotechnol.

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There is growing interest in whether the myelinated nerve fiber acts as a dielectric waveguide to propagate terahertz to mid-infrared electromagnetic waves, which are presumed stable signal carrier for neurotransmission. The myelin sheath is formed as a multilamellar biomembrane structure, hence insights into the dielectric properties of the phospholipid bilayer is essential for a complete understanding of the myelinated fiber functioning. In this work, by means of atomistic molecular dynamics simulations of the dimyristoylphosphatidylcholine (DMPC) bilayer in water and numerical calculations of carefully layered molecules along with calibration of optical dielectric constants, we for the first time demonstrate the spatially resolved (in sub-nm) dielectric spectrum of the phospholipid bilayer in a remarkably wide range from terahertz to mid-infrared. More specifically, the membrane head regions exhibit both larger real and imaginary permittivities than that of the tail counterparts in the majority of the 1–100 THz band. In addition, the spatial variation of dielectric properties suggests advantageous propagation characteristics of the phospholipid bilayer in a relatively wide band of 55–85 THz, where the electromagnetic waves are well confined within the head regions.

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Section: Introductionmentioning

confidence: 99%

Dielectric dispersion characteristics of the phospholipid bilayer with subnanometer resolution from terahertz to mid-infrared

Zhang¹,

Li²,

Xiang³

et al. 2022

Front. Bioeng. Biotechnol.

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Pressure estimation via measurement of reduced light scattering coefficient by oblique laser incident reflectometry

Abookasis,

Malchi,

Robinson

et al. 2024

Journal of Laser Applications

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Continuous measurement of pressure is vital in many fields of industry, medicine, and science. Of particular interest is the ability to measure pressure in a noninvasive and contact-free manner. This work presents the potential of oblique incident reflectometry (OIR) to monitor variation in pressure via the reduced scattering parameter (μs′). Pressure deforms the geometry of the medium and causes distortion of its internal structure and the spatial distribution of optical properties. Light scattering is related to the morphology (size, density, distribution, etc.) and refractive index distributions of the medium, and applied pressure will influence directly these parameters. Therefore, we assume that pressure can be quantitatively assessed through monitoring the reduced scattering coefficient. For this purpose, the technique of OIR to evaluate the scattering parameter during pressure variations was utilized. OIR is a simple noninvasive and contact-free imaging technique able to quantify both absorption and scattering properties of a sample. In our setup, the medium is illuminated obliquely by a narrow laser beam, and the diffuse reflectance light is captured by a CCD camera. In offline processing, the shift (δ) of the diffuse light center from the incident point is mathematically analyzed and μs′ coefficient (μs′∼δ−1) is extracted. We present here confirmation of the validity of this assumption through results of a series of experiments performed on turbid liquid and artery occlusion of a human subject under different pressure levels. Thus, μs′ has the potential to serve as a good indicator for the monitoring of pressure.

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Parametric handheld optical probe (HOPE) for biological tissue characterization in the near-infrared spectral range

Cited by 2 publications

References 57 publications

Dielectric dispersion characteristics of the phospholipid bilayer with subnanometer resolution from terahertz to mid-infrared

Dielectric dispersion characteristics of the phospholipid bilayer with subnanometer resolution from terahertz to mid-infrared

Pressure estimation via measurement of reduced light scattering coefficient by oblique laser incident reflectometry

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