Photophysical and thermodynamic parameters of hematoporphyrin in solutions and monolayers

Abstract

To achieve better understanding of anticancer photosensitizing efficiency and cellular membrane location ability, a study of hematoporphyrin and phospholipids in a dye and in a mixture of a dye and lipids in volumetric and 2D systems was performed. By means of steady-state absorption, fluorescence, and time-resolved optoacoustic spectroscopy, the fluorescence quantum yield, the fraction of absorbed energy converted into heat on a subnanosecond timescale, the efficiency of the dye's triplet-state population, and singlet oxygen generation characteristics of the dye were determined in chosen organic solvents. On the basis of the isotherms of hematoporphyrin and its mixture with phospholipid in Langmuir monolayers, the excess area, excess Gibbs energy, and compression modulus were estimated and the molecular interactions in the model systems investigated were discussed. © 2012 The Author(s).