1 January 2001 Photochemical effects and hypericin photosensitized processes in collagen
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J. of Biomedical Optics, 6(1), (2001). doi:10.1117/1.1331559
Abstract
Emission and excitation spectra of collagen were recorded in the ultraviolet and visible regions. The existence of several types of chromophores absorbing and emitting throughout these spectral regions was observed. It was shown that laser irradiation at 355 and 532 nm caused collagen fluorescence photobleaching by 30%, when the delivered light doses were 9 and 18 J/cm2, respectively. This process of collagen fluorophores photodestruction was found to be a onephoton effect. The effect of hypericin (HYP), a polycyclic quinone, photosensitization on collagen was also studied. Addition of HYP aqueous solution to collagen produced quenching, redshift of the maximum, and broadening of the spectral form of its fluorescence. These effects became more prominent with increasing HYP concentration. The fluorescence of HYP sensitized collagen decreased in a spectrally nonproportional manner during laser irradiation at both 355 and 532 nm.
Dido M. Yova, Vladimir A. Hovhannisyan, Theodossis Theodossiou, "Photochemical effects and hypericin photosensitized processes in collagen," Journal of Biomedical Optics 6(1), (1 January 2001). http://dx.doi.org/10.1117/1.1331559
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KEYWORDS
Collagen

Luminescence

Chromophores

Laser irradiation

Visible radiation

Ultraviolet radiation

Absorption

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