<b>THE EFFECT OF ULTRAVIOLET B IRRADIATION ON THE ISOLATED PORCINE STRATUM CORNEUM: COLORIMETRIC AND ATR/FT-IR SPECTROSCOPIC </b><b>INVESTIGATIONS </b>

Abstract

To investigate the effect of ultraviolet B (UVB) on the isolated stratum corneum (SC), attenuated total reflectance/Fourier transform infrared spectroscopy and tristimulus colorimeter were used to evaluate the changes in secondary structure of proteins and in skin color following UVB irradiation. After UVB radiation, the color of porcine SC became blanching with the increase of exposure time, because melanin pigmentation did not occur in the isolated porcine SC. The peaks assigned to lipid structure disappeared, and some peaks split into additional peaks and/or shifted to lower frequency, possibly because of the unsaturation of protein and lipid in the porcine SC after UVB irradiation. Moreover, the peak area of amide II was decreased with the exposure time, due to the denaturation of protein induced by UVB. The oz-helix structure was transformed into ,6-sheet structure after UVB irradiation on the isolated porcine SC.