Effect of solar radiation on collagen membranes. Possible implicances for human skin

G. RUDERMAN; I.G. MOGILNER; E.J. TOLOSA; R.D. PIACENTINI; R.J. GRIGERA

Montevideo, Uruguay

Conferencia; ICBP 2007; 2007

IUPAB/IUPAP

The effect of solar radiation on the collagen membranes recently presented (patent Nº253249 of 1999 and AR048387 of 2006) was investigated. The membranes were exposed to solar radiation and the effect was evaluated by measuring the coresponding spectra between 180nm and 500nm. These esperiments were performed for both, ordered and non ordered membranes. The exposure was performed in a special chamber that presents good transmitance to the UV component and prevent the deterioration due to intense winds and rains while prevent the direct deposition of dust. The chamber was located near the radiometers that measure the global UV and biological (erythemal) solar irradiances at the top of the Astronomical Observatory of Rosario, Argentina. The exposure was evaluated according to the international definition of the UV index. The membranes were exposed for varying periods between 10 and 64 days along 2005, 2006 and 2007, in order to test the possible modification (and consequent deterioration) that solar UV photons of different intensities and doses, could induce. Transmitance spectra of the membranes, between 180nm and 500nm were measured before and after exposure. The results show a significant modification of the transmitance in the UVB range (290-320nm) that extends to lower wavelengths. This behaviour indicate a true modification at a molecular level that is being interpreted. In the case of the ordered membranes, these experiments were also performed with  deposition of some sunscreen on the upper side. All results are discussed in terms of the implicances for human skin.