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Spectroscopic observations on human pigmentation
Author(s) -
Sadiq Iqbal,
Kollias Nikiforos,
Baqer Ali
Publication year - 2019
Publication title -
photodermatology, photoimmunology and photomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.736
H-Index - 60
eISSN - 1600-0781
pISSN - 0905-4383
DOI - 10.1111/phpp.12474
Subject(s) - melanin , vitiligo , absorbance , human skin , spectral line , absorption (acoustics) , absorption spectroscopy , materials science , irradiation , chemistry , analytical chemistry (journal) , optics , dermatology , physics , biology , chromatography , medicine , biochemistry , composite material , astronomy , nuclear physics , genetics
Background The main chromophores of human skin are melanins and hemoglobins along with carotenoids, bilirubin, and other compounds. In an effort to study the spectral signatures of skin melanin, we measured absorption spectra in a variety of situations, including a method to show early signs of re‐pigmentation in vitiligo. Methods To measure skin in vivo, the essential component was a "Bifurcated Optical Fiber" with one end connected to the light source and the second end connected to the spectrometer while the common end was placed on the skin. Results In a typical in situ “melanin in skin” spectrum, the absorbance values first rise gradually, from 750 to 600 nm, then rise moderately from 600 to 450 nm, and rise sharply from 450 nm to a broad peak at 335 nm, below which it gradually rolls down to much lower values. Conclusion We successfully studied melanin spectroscopically in subjects with vitiligo lesions, obtaining the differential spectra. Higher melanin levels can be shown by steeper negative slopes of a straight line fitted between 620 and 720 nm. Also, absorption peak at 335 nm showed the presence of melanin.