Crown- and phosphoryl-containing metal phthalocyanines in solutions of poly(N-vinylpyrrolidone): Supramolecular organization, accumulation in cells, photo-induced generation of reactive oxygen species, and cytotoxicity

Abstract

Nowadays, the study of well-known sensitizers for photodynamic therapy and search for new ones are intensively conducted. In the present work supramolecular organization of crown-ether and phosphoryl-containing phthalocyanines ({Mgcr₈Pc, I, and М[R₄Pc] (M = Zn²⁺, R = -OPhP(O)(OH)(OC₅H₁₁), II; M = 2H⁺, R = -OPhP(O)(OH)(OC₅H₁₁), III; M = 2H⁺, -OPhP(O)(OH)₂), IIIa}, respectively) was studied in microheterogeneous media. The role of a metal ion of a macrocycle in monomerization of phosphoryl-containing Pc in the presence of water-soluble poly(N-vinylpyrrolidone) was revealed. Some photobiological properties of compound I as possible photosensitizer with respect to human adenocarcinoma cells, HeLa, were analyzed. So, the light and dark cytotoxicity of I (IC₅₀ dose) was 1.83 μМ and higher than 25 μМ, respectively. The reactive oxygen species (ROS) formation studied with use of fluorescent ROS detector DCFH₂ revealed the plateau on the curves of fluorescence intensity vs time after 30 min of irradiation and ROS are almost not produced after the end of irradiation. In HeLa cells, accumulation of compounds I and II as well as fluorescent DCF presence were shown by confocal microscopic images. At concentration of 5 μM, compound I easily penetrates into the cell localizing primarily in the perinuclear region, whereas compound II mainly remains in the periphery of the cells in the fluorescent-active state. The results obtained allow us to continue the study of these interesting compounds.

Keywords: Crown- and phosphoryl-containing phthalocyanines; Cytotoxicity; HeLa cells; Localization; Photodynamic action; Reactive oxygen species; Supramolecular organization.