Elimination of yeast photosensitized by a polymer surface doped with porphyrin

M. GABRIELA ÁLVAREZ, M. LORENA GOMEZ, SABRINA J. MORA, M. ELISA MILANESIO, EDGARDO N. DURANTINI

San Juan

Congreso; 2da Reunión Conjunta Sociedades de Biología; 2011

Photodynamic inactivation (PDI) has been proposed for the treatment of pathogenic microorganisms. The combined action of a photosensitizing agent and visible light leads to a lethal damage in microbes. In these systems, the removal of the sensitizer after the treatment may be necessary due to the accumulation of the agent in living organisms. In this work we synthesized bridged silsesquioxane films doped with 5-(4-carboxyphenyl)- 10,15,20-tris (4-methylphenyl)porphyrin, in order to obtain an surface with aseptic properties activated by visible light. Absorption and fluorescence studies of surface shows the bands characteristic of porphyrins. Also, the film produces singlet molecular oxygen as the main cytotoxic species. In biological systems, the photodynamic effect was studied in Candida albicans. Inactivating action of the surface produces a decrease of ~ 1 and ~ 2 logs in cell viability after 30 and 60 min of irradiation, respectively. This activity was also confirmed by phototoxic studies of delay in the growth curve of yeast. The main advantage of using polymer surfaces is that it can produce PDI of microbes in a liquid suspension irradiating with visible light without polluting the environment with the sensitizer. The difference with other systems is that the film can be removed easily and then it can be reused in new PDI procedures.