Raman spectra of human skin and nail excited in the visible region

Faria, Dalva Lúcia Araújo de; Souza, M. A.

doi:10.1002/(sici)1097-4555(199903)30:3<169::aid-jrs365>3.0.co;2-p

Cited by 24 publications

(23 citation statements)

References 19 publications

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“…45 The use of a laser wavelength in the visible region, known to cause strong native background fluorescence when analysing biological matrices, was not found to be a problem. Two characteristic peaks synonymous to collagen Type I (1650 cm 1 (C O) Amide I and 1444 cm 1 υ CH 2 /CH 3 , respectively) 46 were not detected in any of our spectra. This could be due to the choice of a 632.8 nm laser over a 785 nm near-infrared laser, resulting in strong Raman signals from the pigments over any features that may have been produced from the biological system of the skin.…”

Section: Discussionmentioning

confidence: 52%

In situ chemical analysis of modern organic tattooing inks and pigments by micro‐Raman spectroscopy

Poon

Dadour

McKinley

2008

J Raman Spectroscopy

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The chemical composition of tattooing pigments has varied greatly over time according to available technologies and materials. Beginning with naturally derived plant and animal extracts, to coloured inorganic oxides and salts, through to the modern industrial organic pigments favoured in today's tattooing studios. The demand for tattooing is steadily growing as it gains cultural popularity and acceptance in today's society, but ironically, increasing numbers of individuals are seeking laser removal of their tattoos for a variety of reasons. Organic pigments are favoured for tattooing because of their high tinting strength, light fastness, enzymatic resistance, dispersion and relatively inexpensive production costs. Adverse reactions have been reported for some organic inks, as well as potential complications, during laser removal procedures stemming from the unintentional creation of toxic by-products. Currently, regulatory bodies such as the US Food and Drug Administration have not approved any coloured inks to be injected into the skin, and tattoo ink manufacturers often do not disclose the ingredients in their products to maintain proprietary knowledge of their creations. A methodology was established using micro-Raman spectroscopy on an animal model to correctly identify the constituents of a selection of modern, organic tattoo inks in situ or post procedure, within the skin. This may serve as a preliminary tool prior to engaging in Q-switched laser removals to assess the risks of producing potentially hazardous compounds. Likewise, the pigments responsible for causing adverse reactions in some patients may be quickly identified to hasten any corresponding treatment.

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Section: Discussionmentioning

confidence: 52%

In situ chemical analysis of modern organic tattooing inks and pigments by micro‐Raman spectroscopy

Poon

Dadour

McKinley

2008

J Raman Spectroscopy

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“…Experimental approaches to background/baseline correction are not suitable here. [29][30][31][32][33][34] A chemometric approach (of which there are many) was preferred because this could be more easily implemented on conventional Raman systems. [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Morphological weighted penalized least squares (MPLS) 49 was used for baseline correction of Raman spectra because of its inherent simplicity, combined with its flexibility, suitability for automation, and effectiveness at mitigating baseline artefacts.…”

Section: Resultsmentioning

confidence: 52%

Low-Content Quantification in Powders Using Raman Spectroscopy: A Facile Chemometric Approach to Sub 0.1% Limits of Detection

et al. 2015

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Publication InformationLi, B.; Calvet, A.; Casamayou-Boucau, Y.; Morris, C.; Ryder, A.G. (2015) 'Low-content quantification in powders using Raman spectroscopy: a facile chemometric approach to sub 0.1% limits of detection'. Analytical Chemistry, 87 (6):3419-3428. PublisherAmerican Chemical Society Low-content quantification in powders using Raman spectroscopy: a facile chemometric approach to sub 0.1% limits of detection.Boyan Li, Amandine Calvet, Yannick Casamayou-Boucau, Cheryl Morris, and Alan G. Ryder* Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Galway, Ireland.* To whom correspondence should be addressed.Tel: +3539149 2943 Email: alan.ryder@nuigalway.ie ABSTRACT A robust and accurate analytical methodology for low-content (<0.1%) quantification in the solid-state using Raman spectroscopy, sub-sampling, and chemometrics was demonstrated using a piracetam-proline model. The method involved a 5-step process: collection of relatively large number of spectra (8410) from each sample by Raman mapping, meticulous data pretreatment to remove spectral artefacts, use of a 0-100% concentration range partial least squares (PLS) regression model to estimate concentration at each pixel, use of a more-accurate, reduced concentration range PLS model to accurately calculate analyte concentration at each pixel, and finally statistical analysis of all 8000+ concentration predictions to produce an accurate overall sample concentration. The relative prediction accuracy was ~2.4% for a 0.05~1.0% concentration range and the limit of detection was comparable to high performance liquid chromatography (0.03% versus 0.041%). For data pretreatment, we developed a unique cosmic ray removal method and used an automated baseline correction method, neither of which required subjective user intervention and thus were fully automatable. The method is applicable to systems, which cannot be easily analyzed chromatographically such as hydrate, polymorph, or solvate contamination.

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“…These spectra present features related to vibrations of functional groups of proteins, nucleic acids and lipids. 7,20,21 The spectra not only show some similarities but also some clear differences in feature-signatures and intensities. In particular, the spectra are dominated by bands 20,21 corresponding to amide I in the 1655 cm 1 region, to CH 2 /CH 3 scissoring around 1449 cm 1 , to amide III at 1269 cm 1 and to CC stretch of phenylalanine at 1003 cm 1 .…”

Section: Healthy Skinmentioning

confidence: 99%

“…These features are characteristic of ceramide, which is the most abundant class of stratum corneum lipids 8,22 and thus are a result of the lipid signal contribution to the spectrum. The spectrum of stratum corneum (Fig 1(a)) resembles previously measured spectra using FT-Raman spectroscopy, of isolated stratum corneum 6,20,23,24 and particularly, the average spectrum that was obtained from several measurements at different positions in the stratum corneum by confocal Raman spectroscopy. 8 The spectrum of dermis ( Fig.…”

Section: Healthy Skinmentioning

confidence: 99%

Bullous pemphigoid detection by micro-Raman spectroscopy and cluster analysis: structure alterations of proteins

Azrad

Cagnano

Halevy

et al. 2005

J. Raman Spectrosc.

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In this study, micro-Raman spectroscopy was used, for the first time, to detect spectral changes between healthy and diseased skin tissues with bullous pemphigoid (BP). The spectral changes provide information about the biochemical alterations between normal skin and blistered and nonblistered regions in samples diagnosed histopathologically as BP. Raman spectra, characterized by many peaks, revealed the molecular composition of the different skin layers, stratum corneum, epidermis and dermis of normal skin. Comparison of spectra monitored at the dermoepidermal junction (DEJ) of healthy skin with those of blisters caused by BP showed evidence for large variations in the amide I and III regions. The alterations of the protein content, amide I and III, are a result of the appearance of immunoglobulin G (IgG) and fibrin, characteristics of BP. Indication for the disease at early stages was obtained from changes in protein content, evidenced in the measured spectra assisted by cluster analysis. The method employed here can contribute to the nearly real-time diagnosis and to a better understanding of the physical and biomolecular processes effected by BP, and might have implications on other skin diseases.

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Raman spectra of human skin and nail excited in the visible region

Cited by 24 publications

References 19 publications

In situ chemical analysis of modern organic tattooing inks and pigments by micro‐Raman spectroscopy

In situ chemical analysis of modern organic tattooing inks and pigments by micro‐Raman spectroscopy

Low-Content Quantification in Powders Using Raman Spectroscopy: A Facile Chemometric Approach to Sub 0.1% Limits of Detection

Bullous pemphigoid detection by micro-Raman spectroscopy and cluster analysis: structure alterations of proteins

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