Energy transfer among dyes on particulate solids

Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure...

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Autores principales:	Rodríguez, Hernán Bernardo, Iriel, Analía, San Roman, Enrique Arnoldo
Publicado:	2006
Materias:	cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00318655_v82_n1_p200_Rodriguez http://hdl.handle.net/20.500.12110/paper_00318655_v82_n1_p200_Rodriguez
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00318655_v82_n1_p200_Rodriguez
record_format	dspace
spelling	paper:paper_00318655_v82_n1_p200_Rodriguez2023-06-08T14:57:21Z Energy transfer among dyes on particulate solids Rodríguez, Hernán Bernardo Iriel, Analía San Roman, Enrique Arnoldo cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure MB builds up dimeric species on cellulose even at 2 × 10 -8 mol g -1, addition of 2.05 × 10 -7 mol g -1 Pheo largely inhibits aggregation up to nearly 10 -6 mol g -1 MB. At the same time, the absorption spectrum of monomeric MB in the presence of Pheo differs from the spectrum in pure cellulose. Both effects reveal a strong influence of Pheo on the medium properties. A model relying entirely on experimental data is developed, through which energy transfer efficiencies can be calculated for thin and thick layers of dye-loaded cellulose. At the largest concentration of MB assuring no dye aggregation, nonradiative energy transfer efficiencies reach a maximum value of nearly 40%. This value is quite high, taking into account the low fluorescence quantum yield of Pheo, Φ = 0.21, and results from the existence of high local concentrations of the acceptor within the supporting material. These results show that large energy transfer rates can exist in a system devoid of any special molecular organization. © 2006 American Society for Photobiology. Fil:Rodriguez, H.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Iriel, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:San Román, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2006 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00318655_v82_n1_p200_Rodriguez http://hdl.handle.net/20.500.12110/paper_00318655_v82_n1_p200_Rodriguez
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry
spellingShingle	cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry Rodríguez, Hernán Bernardo Iriel, Analía San Roman, Enrique Arnoldo Energy transfer among dyes on particulate solids
topic_facet	cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry
description	Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure MB builds up dimeric species on cellulose even at 2 × 10 -8 mol g -1, addition of 2.05 × 10 -7 mol g -1 Pheo largely inhibits aggregation up to nearly 10 -6 mol g -1 MB. At the same time, the absorption spectrum of monomeric MB in the presence of Pheo differs from the spectrum in pure cellulose. Both effects reveal a strong influence of Pheo on the medium properties. A model relying entirely on experimental data is developed, through which energy transfer efficiencies can be calculated for thin and thick layers of dye-loaded cellulose. At the largest concentration of MB assuring no dye aggregation, nonradiative energy transfer efficiencies reach a maximum value of nearly 40%. This value is quite high, taking into account the low fluorescence quantum yield of Pheo, Φ = 0.21, and results from the existence of high local concentrations of the acceptor within the supporting material. These results show that large energy transfer rates can exist in a system devoid of any special molecular organization. © 2006 American Society for Photobiology.
author	Rodríguez, Hernán Bernardo Iriel, Analía San Roman, Enrique Arnoldo
author_facet	Rodríguez, Hernán Bernardo Iriel, Analía San Roman, Enrique Arnoldo
author_sort	Rodríguez, Hernán Bernardo
title	Energy transfer among dyes on particulate solids
title_short	Energy transfer among dyes on particulate solids
title_full	Energy transfer among dyes on particulate solids
title_fullStr	Energy transfer among dyes on particulate solids
title_full_unstemmed	Energy transfer among dyes on particulate solids
title_sort	energy transfer among dyes on particulate solids
publishDate	2006
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00318655_v82_n1_p200_Rodriguez http://hdl.handle.net/20.500.12110/paper_00318655_v82_n1_p200_Rodriguez
work_keys_str_mv	AT rodriguezhernanbernardo energytransferamongdyesonparticulatesolids AT irielanalia energytransferamongdyesonparticulatesolids AT sanromanenriquearnoldo energytransferamongdyesonparticulatesolids
_version_	1768545544156741632

Energy transfer among dyes on particulate solids

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