Paper
22 June 1999 UV radiation at the fluorescence excitation maxima produces significant changes in the fluorescence of skin
Nikiforos Kollias, W. D. Tian, George I. Zonios, Lorenzo Brancaleon, Robert Gillies
Author Affiliations +
Proceedings Volume 3590, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems IX; (1999) https://doi.org/10.1117/12.350994
Event: BiOS '99 International Biomedical Optics Symposium, 1999, San Jose, CA, United States
Abstract
Fluorescence excitation spectra of skin have been determined to be stable and reproducible. Three major bands dominate the wavelength range 280-400 nm. The major epidermal band due to tryptophan moieties appears at 295±5 nm and the major dermal bands due to collagen cross links appear at 335±5 nm and at 370±5 nm. The tryptophan fluorescence intensity has been found to increase with exposure to UV radiation; the UVB wavelengths are more effective than the UVA wavelengths. The PDCCL fluorescence intensity has been found to decrease dramatically with exposure to UVA in a wavelength specific way. The maximum of the action spectrum for this process is centered at the maximum of the excitation spectrum. The fluorescence of the skin recovers within 24 hours following exposure to UVA from single exposures. Multiple exposures produce permanent changes, in a follow-up of 8 weeks. the changes in the tryptophan fluorescence are probably due to changes in the molecular environment brought about by changes in the electrolyte balance in the epidermis following exposure. The changes in the dermis following UVA exposure appear to be associated with change in the collagen cross links, either through their association with other dermal species leading to quenching of the fluorescence or by the formation of stronger cross links with a smaller quantum efficiency. As these changes are immediate both alterations may provide the means for in vivo UV dosimetry.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nikiforos Kollias, W. D. Tian, George I. Zonios, Lorenzo Brancaleon, and Robert Gillies "UV radiation at the fluorescence excitation maxima produces significant changes in the fluorescence of skin", Proc. SPIE 3590, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems IX, (22 June 1999); https://doi.org/10.1117/12.350994
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KEYWORDS
Luminescence

Skin

Ultraviolet radiation

Collagen

Chromophores

Monochromators

Absorption

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