INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Fluorescence and Molecular Singlet Oxygen Generation in Thin Films: Phloxine B in Poly(2-Hydroxyethyl Methacrylate)
Autor/es:
YAIR LITMAN; HERNÁN B. RODRÍGUEZ; ENRIQUA SAN ROMÁN
Lugar:
Córdoba
Reunión:
Congreso; 16th International Congress on Photobiology; 2014
Resumen:
Phloxine B (PhB) is a hydrophilic dye used in drugs and cosmetics. It has low toxicity in the dark but it is currently used as photoinsecticide because it generates singlet molecular oxygen (1O2) on illumination. Poly(2-hydroxyethyl methacrylate) (PHEMA) is a bio-compatible polymer that forms hydrogels in water and, conveniently crosslinked, builds up hardly hydrolizable materials. Preliminary experiments are described, based on PhB incorporated in 100300 nm thick 20 kDa PHEMA films obtained by spin coating on glass substrates. Samples were characterized by absorption and emission spectroscopies. Fluorescence quantum yields were obtained using PhB in ethanol as a reference (ΦF = 0.76 ± 0.02). 1O2 formation was evaluated using 1,3-diphenylisobenzofuran as chemical quencher in dichloromethane. Generation of 1O2 is limited only by the formation of statistical traps at high dye concentrations. Themaximum rate for a given illumination is obtained around [PhB] = 0.010 M, where the product betweenabsorptance and quantum yield attains its maximum. Potential applications in photodynamicantimicrobial chemotherapy and other fields are discussed.