Agar phantoms of biological tissue for fluorescence monitoring of photodynamic therapy

2022 ◽  
Vol 52 (1) ◽  
pp. 63-68
Author(s):  
A V Khilov ◽  
V A Shishkova ◽  
E A Sergeeva ◽  
D A Kurakina ◽  
M Yu Kirillin
Keyword(s):  
Optical Properties ◽  
Photodynamic Therapy ◽  
Intravenous Injection ◽  
Biological Tissue ◽  
Biological Tissues ◽  
Fluorescent Properties ◽  
Fluorescent Marker ◽  
Scattering Coefficients ◽  
Scattering Spectra ◽  
Good Agreement

Abstract An approach to fabricating agar phantoms mimicking spectral optical properties of biological tissues with fluorescent inclusions is proposed, which allows one to imitate the problem of optical visualisation of superficial biological tissues after the administration of a chlorin-based photosensitiser. The different arrangement of a fluorescent layer within a phantom makes it possible to simulate biological tissue in the cases of both topical application and intravenous injection of a photosensitiser. It is shown that absorption and scattering spectra of phantoms are in good agreement with the spectra of real biological tissues in the wavelength range of 500-800 nm. Changes in spectra of absorption and scattering coefficients of phantoms, as well as in their fluorescent properties induced by the addition of a fluorescent marker (chlorinbased photosensitiser) are demonstrated.

scholarly journals Time-Resolved Reflectance Spectroscopy Applied to the Nondestructive Monitoring of the Internal Optical Properties in Apples

2001 ◽  
Vol 55 (10) ◽  
pp. 1368-1374 ◽  
Author(s):  
Rinaldo Cubeddu ◽  
Cosimo D'Andrea ◽  
Antonio Pifferi ◽  
Paola Taroni ◽  
Alessandro Torricelli ◽  
...  
Keyword(s):  
Optical Properties ◽  
Industrial Applications ◽  
Nondestructive Monitoring ◽  
Nondestructive Measurement ◽  
Time Resolved ◽  
Mean Values ◽  
Scattering Coefficients ◽  
Scattering Spectra ◽  
The Mean ◽  
Temporal Dispersion

Time-resolved reflectance has been used for the nondestructive measurement of optical properties in apples. The technique is based on the detection of the temporal dispersion of a short laser pulse injected into the probed medium. The time distribution of re-emitted photons interpreted with a solution of the diffusion equation yields the mean values of the absorption and reduced scattering coefficients of the medium. The proposed technique proved useful for the measurement of the absorption and scattering spectra of different varieties of apples, revealing the spectral shape of chlorophyll. No major variations were observed in the experimental data when the fruit was peeled, showing that the optical properties measured were those of the pulp. With this technique the change in chlorophyll absorption during storage and ripening could be followed. Finally, a compact prototype working at few selected wavelengths was designed and constructed, demonstrating potentialities of the technique for industrial applications.

scholarly journals Determination of the optical properties of bovine liver tissue using integrating sphere technique

2018 ◽  
Vol 1 (1) ◽  
pp. 248-252
Author(s):  
Halil Arslan ◽  
Yasar Baris Dolukan
Keyword(s):  
Optical Properties ◽  
Liver Tissue ◽  
Tissue Sample ◽  
Bovine Liver ◽  
Integrating Sphere ◽  
Scattering Coefficients ◽  
Single Sphere ◽  
Microscope Slides ◽  
Good Agreement

The optical properties (absorption and reduced scattering coefficients, µa and µs’) of bovine liver tissue for 635 nm has been determined by using integrating sphere and inverse adding-doubling (IAD) techniques. For this purpose, total reflectance and total transmittance values of bovine liver tissue sample, which is placed between two microscope slides, have been measured by using single-sphere system. The measured values have been used as input parameters for IAD program to extract the µa and µs’ of the sample. In this study, µa and µs’ of bovine liver tissue for 635 nm have been determined to be 0.22 mm-1 and 0.51mm-1, respectively. These values, which yield 1.44 mm penetration depth, are in good agreement with the ones in the literature.

scholarly journals Измерение оптических свойств десны и дентина человека в спектральном диапазоне 350–800 нм

2020 ◽  
Vol 20 (4) ◽  
pp. 258-267
Author(s):  
Alexey Andreevich Selifonov ◽  
◽  
Olga Anatolyevna Zyuryukina ◽  
Ekaterina Nikolaevna Lazareva ◽  
Julia Sergeevna Skibina ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spectral Range ◽  
Photothermal Therapy ◽  
Diffuse Reflection ◽  
Biological Tissues ◽  
Transmission Spectra ◽  
Tissue Samples ◽  
Scattering Coefficients ◽  
Total Transmission

Knowledge of the optical properties of biological tissues is important for the development of optical diagnostics, photodynamic and photothermal therapy of various diseases. However, despite the significant number of works devoted to the determination of the optical properties of tissues, the optical properties of human gums and dentin remain currently poorly understood. In this work, we experimentally studied the optical properties of human gums and dentin in the spectral range from 350 nm to 800 nm. Basing on measured diffuse reflection and total transmission spectra and using the Inverse Adding Doubling (IAD) method, the spectral dependences of absorption and scattering coefficients of the studied tissue samples were calculated.

scholarly journals Artificial neural networks based estimation of optical parameters by diffuse reflectance imaging under in vitro conditions

2017 ◽  
Vol 10 (01) ◽  
pp. 1650027 ◽  
Author(s):  
Mahmut Ozan Gökkan ◽  
Mehmet Engin
Keyword(s):  
Neural Networks ◽  
Optical Properties ◽  
Artificial Neural Networks ◽  
Biological Tissue ◽  
Diffuse Reflectance ◽  
Optical Parameters ◽  
Scattering Coefficients ◽  
Surface Image ◽  
Artificial Neural

Optical parameters (properties) of tissue-mimicking phantoms are determined through noninvasive optical imaging. Objective of this study is to decompose obtained diffuse reflectance into these optical properties such as absorption and scattering coefficients. To do so, transmission spectroscopy is firstly used to measure the coefficients via an experimental setup. Next, the optical properties of each characterized phantom are input for Monte Carlo (MC) simulations to get diffuse reflectance. Also, a surface image for each single phantom with its known optical properties is obliquely captured due to reflectance-based geometrical setup using CMOS camera that is positioned at 5[Formula: see text] angle to the phantoms. For the illumination of light, a laser light source at 633[Formula: see text]nm wavelength is preferred, because optical properties of different components in a biological tissue on that wavelength are nonoverlapped. During in vitro measurements, we prepared 30 different mixture samples adding clinoleic intravenous lipid emulsion (CILE) and evans blue (EB) dye into a distilled water. Finally, all obtained diffuse reflectance values are used to estimate the optical coefficients by artificial neural networks (ANNs) in inverse modeling. For a biological tissue it is found that the simulated and measured values in our results are in good agreement.

scholarly journals Nondestructive Evaluation of Apple Fruit Quality by Frequency-Domain Diffuse Reflectance Spectroscopy: Variations in Apple Skin and Flesh

2019 ◽  
Vol 9 (11) ◽  
pp. 2355 ◽  
Author(s):  
Nan-Yu Cheng ◽  
Chien-Chih Chen ◽  
Bo-Jian Liang ◽  
Sheng-Hao Tseng
Keyword(s):  
Optical Properties ◽  
Nondestructive Evaluation ◽  
Frequency Domain ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Biological Tissues ◽  
Reflectance Spectroscopy ◽  
Apple Fruit ◽  
Scattering Coefficients

The optical properties of fruits, such as light absorption and scattering characteristics, change with biochemical activities during storage. Diffuse reflectance spectroscopy (DRS) systems have been widely applied for noninvasively observing biological tissues. In this study, we used a frequency-domain DRS system to measure the optical properties of apples. Results showed that variations in the chlorophyll, water, and flesh-texture of apples could be noninvasively monitored over time. We also observed substantial differences in the absorption and reduced scattering coefficients between injured and normal apples. The DRS techniques could be used for apple grading, and, by extension, for monitoring the quality of other fruits.

Optical Properties of Photodynamic Therapy Drugs in Different Environments: The Paradigmatic Case of Temoporfin

2020 ◽  
Author(s):  
busenur Aslanoglu ◽  
Ilya Yakavets ◽  
Vladimir Zorin ◽  
Henri-Pierre Lassalle ◽  
Francesca Ingrosso ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Optical Properties ◽  
Photodynamic Therapy ◽  
Minimally Invasive ◽  
Visible Light ◽  
Cancer Treatment ◽  
Singlet Oxygen ◽  
Tumor Cells ◽  
Molecular Oxygen ◽  
Computational Tools

Computational tools have been used to study the photophysical and photochemical features of photosensitizers in photodynamic therapy (PDT) –a minimally invasive, less aggressive alternative for cancer treatment. PDT is mainly based by the activation of molecular oxygen through the action of a photoexcited sensitizer (photosensitizer). Temoporfin, widely known as mTHPC, is a second-generation photosensitizer, which produces the cytotoxic singlet oxygen when irradiated with visible light and hence destroys tumor cells. However, the bioavailability of the mostly hydrophobic photosensitizer, and hence its incorporation into the cells, is fundamental to achieve the desired effect on malignant tissues by PDT. In this study, we focus on the optical properties of the temoporfin chromophore in different environments –in <i>vacuo</i>, in solution, encapsulated in drug delivery agents, namely cyclodextrin, and interacting with a lipid bilayer.

scholarly journals Optical signatures of radiofrequency ablation in biological tissues

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pranav Lanka ◽  
Kalloor Joseph Francis ◽  
Hindrik Kruit ◽  
Andrea Farina ◽  
Rinaldo Cubeddu ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Treatment Time ◽  
Ex Vivo ◽  
Biological Tissues ◽  
Tissue Response ◽  
Optical Monitoring ◽  
Diffuse Optical Spectroscopy ◽  
Spectral Changes ◽  
Scattering Spectra ◽  
Optical Behavior

AbstractAccurate monitoring of treatment is crucial in minimally-invasive radiofrequency ablation in oncology and cardiovascular disease. We investigated alterations in optical properties of ex-vivo bovine tissues of the liver, heart, muscle, and brain, undergoing the treatment. Time-domain diffuse optical spectroscopy was used, which enabled us to disentangle and quantify absorption and reduced scattering spectra. In addition to the well-known global (1) decrease in absorption, and (2) increase in reduced scattering, we uncovered new features based on sensitive detection of spectral changes. These absorption spectrum features are: (3) emergence of a peak around 840 nm, (4) redshift of the 760 nm deoxyhemoglobin peak, and (5) blueshift of the 970 nm water peak. Treatment temperatures above 100 °C led to (6) increased absorption at shorter wavelengths, and (7) further decrease in reduced scattering. This optical behavior provides new insights into tissue response to thermal treatment and sets the stage for optical monitoring of radiofrequency ablation.

scholarly journals Changes in Optical Properties upon Dye–Clay Interaction: Experimental Evaluation and Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 197
Author(s):  
Giorgia Giovannini ◽  
René M. Rossi ◽  
Luciano F. Boesel
Keyword(s):  
Optical Properties ◽  
Hybrid Materials ◽  
High Performance ◽  
Fluorescent Properties ◽  
Chemical Mechanisms ◽  
Strong Electrostatic Interaction ◽  
Potential Applications ◽  
Photochemical Properties ◽  
Physical And Chemical ◽  
The Relationship

The development of hybrid materials with unique optical properties has been a challenge for the creation of high-performance composites. The improved photophysical and photochemical properties observed when fluorophores interact with clay minerals, as well as the accessibility and easy handling of such natural materials, make these nanocomposites attractive for designing novel optical hybrid materials. Here, we present a method of promoting this interaction by conjugating dyes with chitosan. The fluorescent properties of conjugated dye–montmorillonite (MMT) hybrids were similar to those of free dye–MMT hybrids. Moreover, we analyzed the relationship between the changes in optical properties of the dye interacting with clay and its structure and defined the physical and chemical mechanisms that take place upon dye–MMT interactions leading to the optical changes. Conjugation to chitosan additionally ensures stable adsorption on clay nanoplatelets due to the strong electrostatic interaction between chitosan and clay. This work thus provides a method to facilitate the design of solid-state hybrid nanomaterials relevant for potential applications in bioimaging, sensing and optical purposes.

scholarly journals Machine learning estimation of tissue optical properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brett H. Hokr ◽  
Joel N. Bixler
Keyword(s):  
Neural Network ◽  
Optical Properties ◽  
Biological Tissues ◽  
Homogeneous Layer ◽  
In Vivo Measurement ◽  
Tissue Optical Properties ◽  
The Neural Network ◽  
Spatio Temporal ◽  
Fully Connected

AbstractDynamic, in vivo measurement of the optical properties of biological tissues is still an elusive and critically important problem. Here we develop a technique for inverting a Monte Carlo simulation to extract tissue optical properties from the statistical moments of the spatio-temporal response of the tissue by training a 5-layer fully connected neural network. We demonstrate the accuracy of the method across a very wide parameter space on a single homogeneous layer tissue model and demonstrate that the method is insensitive to parameter selection of the neural network model itself. Finally, we propose an experimental setup capable of measuring the required information in real time in an in vivo environment and demonstrate proof-of-concept level experimental results.

ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF CRYSTALLINE C60

1992 ◽  
Vol 06 (06) ◽  
pp. 309-321 ◽  
Author(s):  
W.Y. CHING ◽  
MING-ZHU HUANG ◽  
YONG-NIAN XU ◽  
FANQI GAN
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Optical Spectrum ◽  
Local Density ◽  
Low Dielectric Constant ◽  
Experimental Measurements ◽  
Absorption Bands ◽  
Low Dielectric ◽  
Good Agreement

The electronic structure and optical properties of crystalline C 60 and their pressure dependence have been studied by first-principles local density calculations. It is shown that fcc C 60 has a low dielectric constant and an optical spectrum rich in structures. The spectrum shows five disconnected absorption bands in the 1.4 to 7.0 eV region with sharp structures in each band that can be attributed to critical point transitions. This is a manifestation of the localized molecular structure coupled with long range crystalline order unique to the C 60 crystal. At a sufficient high pressure, the structures in the optical spectrum start to merge due to the merging of the bands. These results are in good agreement with some recent experimental measurements.

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