Determination of the complex refractive index of cell cultures by reflectance spectrometry

Calin, Marian Romeo; Munteanu, Constantin

doi:10.1140/epjp/i2014-14116-1

Cited by 6 publications

(9 citation statements)

References 24 publications

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“…The frequency dependent complex dielectric function of gold is approximated by the Brendal-Bormann model which is shown to be in very good agreement with experimental observations in the studied wavelength range [8,9,10]. The refractive index of the environment is set to 1.40 which corresponds to that of living cells [11].…”

Section: Simulation and Modelingsupporting

confidence: 59%

Plasmonic Photothermal Therapy in Third and Fourth Biological Windows

Onal

Güven

2017

J. Phys. Chem. C

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Section: Simulation and Modelingsupporting

confidence: 59%

Plasmonic Photothermal Therapy in Third and Fourth Biological Windows

Onal

Güven

2017

J. Phys. Chem. C

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“…The standard procedure [25] at this point is to equate the reflectance complex amplitude (1) with the (normal incidence) Fresnel Equation (2). Taking into account Equation (4), it is possible to solve explicitly for n 2 and k 2 :…”

Section: Mathematical Basis Of Reflectance Manipulationmentioning

confidence: 99%

“…Equations (5) have been also recently reported [25], but in this case n 1 , the index of refraction of the medium from which radiation is propagating, is explicitly included. In any case, Equations (5) are not general enough to describe correctly some typical microscopic observations of biological samples.…”

Section: Mathematical Basis Of Reflectance Manipulationmentioning

confidence: 99%

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Phase and Index of Refraction Imaging by Hyperspectral Reflectance Confocal Microscopy

Selci

2016

Molecules

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A hyperspectral reflectance confocal microscope (HSCM) was realized by CNR-ISC (Consiglio Nazionale delle Ricerche-Istituto dei Sistemi Complessi) a few years ago. The instrument and data have been already presented and discussed. The main activity of this HSCM has been within biology, and reflectance data have shown good matching between spectral signatures and the nature or evolution on many types of cells. Such a relationship has been demonstrated mainly with statistical tools like Principal Component Analysis (PCA), or similar concepts, which represent a very common approach for hyperspectral imaging. However, the point is that reflectance data contains much more useful information and, moreover, there is an obvious interest to go from reflectance, bound to the single experiment, to reflectivity, or other physical quantities, related to the sample alone. To accomplish this aim, we can follow well-established analyses and methods used in reflectance spectroscopy. Therefore, we show methods of calculations for index of refraction n, extinction coefficient k and local thicknesses of frequency starting from phase images by fast Kramers-Kronig (KK) algorithms and the Abeles matrix formalism. Details, limitations and problems of the presented calculations as well as alternative procedures are given for an example of HSCM images of red blood cells (RBC).

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“…The measurement of the refractive index of cells can be useful for the quantitative study of cellular dynamics, as well as for medical diagnosis and screening of disease . Qualitative and quantitative technologies such as phase contrast microscopy, infrared surface plasmon, and differential interference microscopy have been introduced for the determination of the refractive index of cells . These systems allow spatial distribution imaging of refractive indices ; however, it is difficult to extract analytical data and there are some limitations in these imaging technologies due to optical artifacts and reduced imaging resolution in which technical developments for correcting these limitations make them expensive.…”

Section: Introductionmentioning

confidence: 99%

Non‐invasive Reflectance Spectroscopy for Normal and Cancerous Skin Cells Refractive Index Determination: An In Vitro Study

et al. 2019

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Background and Objective: Optical reflectance spectroscopy is a non-invasive technique for optical characterization of biological samples. Any alteration in a cell from normal or carcinogenic causes will change its refractive index. The aim of this study is to develop a computerized program for extraction of a refractive index of normal and cancerous skin cell lines, including melanoma, fibroblast, and adipose cells, using visible near-infrared reflectance spectra and the Kramers-Kronig (K-K) relations. Materials and Method: A fiber optic reflectance spectrometer in visible near-infrared wavelength was used for spectrum acquisition in an in vitro study. Human skin cell lines for melanoma (A375), fibroblast, and adipose sample were cultured for optical spectroscopy. Following data acquisition, an analytical MATLAB code was developed to run the K-K relations. The program was validated for three biological samples using an Abbe refractometer. Results: The validation error (below 5%) and determination of changes in the refractive index of melanoma, normal fibroblasts, and adipose skin cells was carried out at wavelengths of 450-950 nm. The refractive index of melanoma was 1.59270 ± 0.0550 at 450 nm, the minimum amount of 1.27790 ± 0.0550 to 1.321 ± 0.0550 at 620 nm, and rose sharply to 1.44321 ± 0.0550 at 935 nm. The respective results for fibroblast and adipose tissue cells were 1.33282 ± 0.0134 and 1.28345 ± 0.0163 at 450 nm with an increasing trend to 1.30494 ± 0.0135 and 1.26716 ± 0.0163 at 935 nm. Conclusion: Refractive index characteristics show potential for cancer screening and diagnosis. The results show that optical spectroscopy is a promising, non-invasive tool for assessment of the refractive index of living biological cells in in vitro settings. Tracking changes in the refractive index allows screening of normal and abnormal cells for probable alterations in a non-invasive label-free method. Lasers Surg. Med.

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Determination of the complex refractive index of cell cultures by reflectance spectrometry

Cited by 6 publications

References 24 publications

Plasmonic Photothermal Therapy in Third and Fourth Biological Windows

Plasmonic Photothermal Therapy in Third and Fourth Biological Windows

Phase and Index of Refraction Imaging by Hyperspectral Reflectance Confocal Microscopy

Non‐invasive Reflectance Spectroscopy for Normal and Cancerous Skin Cells Refractive Index Determination: An In Vitro Study

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