Spectral properties of phthalocyanines incorporated into resting and stimulated human peripheral blood cells

Abstract

Human peripheral blood cells stimulated by phytohemagglutinin (which serve as a model of cancerous cells) and resting cells were incubated in dimethyl sulfoxide solutions of various phthalocyanines. In order to diminish the influence of atmospheric oxygen the cells were embedded in a polymer (polyvinyl alcohol) film. Fluorescence spectra of the samples were measured over two regions of excitation wavelengths: at 405 nm (predominant absorption of the cell material) and in the regions of strong absorption of phthalocyanines (at about 605 nm and 337 nm). The intrinsic emission of cell material became changed as a result both of cells' stimulation and of incubation of cells in dye solution. In most cases the stimulated cells when stained by dye exhibited higher long wavelength fluorescence intensity than resting cells. This suggests higher efficiency of dye incorporation into cancerous cells than into healthy cells. The absorption spectra of samples were also measured. The spectra of various phthalocyanines in incubation solvent, in polymer and in the cells embedded in polymer, were compared. The comparison of properties of the cells stimulated for different time periods enabled to establish the conditions of stimulation creating a population of cells incorporating a large number of sensitizing molecules.