The interactions of phthalocyanines with stimulated and resting human peripheral blood mononuclear cells

The interactions of two metal-free phthalocyanines [(H2Pc) and Solar Pc (wi th four peripherical groups: SO2N(CH2CH2OH)(2))] and of one metal substitut ed dye (CoPc) with resting and stimulated human peripheral blood mononuclea r cells (PBMC) were compared. The absorption, fluorescence, photoacoustic and EPR spectra of both resting cells and cells stimulated by phytohaemagglutinin, incubated in dimethyl s ulfoxide (DMSO) with very low or 95% water content and with or without dye addition, were measured. The fate of the light absorbed by the samples was investigated. It is known that singlet oxygen production is crucial for pho todynamic action of dyes. Thermal deactivation and luminescence emission co mpete with this process, so investigation of these alternative paths of sen sitizer deactivation provides information about photodynamic action. The in corporation of the investigated dyes into cells and the perturbation of the cell structure caused by the dyes, the incubation solvent and the activato r were investigated by comparing the spectral properties of PBMC before and after stimulation and incubation. Incubation of the cells for 1 h in a sol ution of Solar Pc in 99.5% aqueous DMSO, resulted in an efficient dye incor poration which was highly selective. Solar Pc being introduced much more ef ficiently into stimulated cells than into resting cells.