Comparação do potencial fotodinâmico de três fotossensibilizadores associados a uma lâmpada de LEDs sobre culturas de Enterococcus faecalis

Abstract

In photodynamic therapy uses a light source, a photosensitizer and oxygen in the reaction to produce highly reactive species as a result capable of causing non-viability of microrganisms such as bacteria and fungi. This research evaluated presumptively strain of Enterococcus faecalis ATCC 29212 and evaluated the optical absorption spectra of the photosensitizers methylene blue and toluidine blue in 0,9% saline solution. The study compared the antimicrobial potential of photosensitizers methylene blue and toluidine blue at concentrations of 2,5 x 10-4 mol/L associated or not with a red LED lamp power 1,5 W on cultures of Enterococcus faecalis. The energy densities applied were 44,7 J/cm2, 89,5 J/cm2 e 179,0 J/cm2. The efficiency of malachite green dye under the same conditions cited study of the dyes but and concentrations ten times smaller and using longer periods of irradiation was also evaluated. The results confirmed the characteristics of the strain bacterin in the study of literature. The spectra of photosensitizers differ in areas of a greater absorption. The lamp itself and the pigments with no light exhibited bactericidal effect on microbial cultures. The methylene blue showed greater photodynamic efficiency in presence and absence of light.