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.

Preliminary studies of phthalocyanine sensitizers incorporated into human leukemia cells from two cell-lines.

“…The absorption of the dyes in this region can be neglected. The long wavelength absorption (about 600-700 nm) in which the Pcs absorption can be expected (Rosenthal, 1991;Waszkowiak et al, 2002) for the Pc dyes incorporated into cells was very low and perturbed by light scattering (not shown). The changes in the cell material absorption and endogenous cell fluorescence due to the cell staining as well as the fluorescence of the Pcs incorporated into cells showed clearly that the dye molecules were present in the stained cells.…”

“…Cells activated by mitogens (e.g. phytohemagglutinin), investigated previously (Waszkowiak et al, 2002;Wiktorowicz et al, 2004), are model systems of malignant cells. To be an efficient photosensitizer for PDT, the dye-sensitizer should be (i) efficiently incorporated into malignant cells, (ii) non-toxic for healthy cells, and (iii) exhibit high yield of triplet states generation.…”

“…These dyes, whose structures are presented in Fig. 1, were previously investigated in various model systems (Frąckowiak et al, 2001a;2001b;Waszkowiak et al, 2002;Wiktorowicz et al, 2004).…”

The phthalocyanines applications in photodynamic therapy investigated by time‐resolved and steady‐state photothermal methods

“…In the case of the tissue, when the dyes are located in similar parts of cell, the ratio of their TD yields should be similar as in other media. The measurements by the PAS of the content of the dyes in the cells are more convenient than the application of the absorption spectra, because PAS results are less perturbed by light scattering than absorption [2,10]. Therefore the presence of dye molecules can be easier established on the ground of PAS than on the basis of absorption spectra.…”

“…Therefore the measurements of fluorescence of stained cells can be also useful for the investigation of dye incorporation. Figure 6 presents fluorescence spectra of the PBMC stained by ZnPc [10]. Emission is excited in two regions: at 405 nm where absorption of inner cell material is higher than that of the dye and at 610 nm or 680 nm where dye absorption predominants.…”