Photodynamic effects of zinc(II) phthalocyanine-loaded polymeric micelles in human nasopharynx KB carcinoma cells

MARIA CECILIA GARCÍA VIOR, JULIETA MARINO,,LEONOR P. ROGUIN, ALEJANDRO SOSNIK, JOSEFINA AWRUCH

PHOTOCHEMISTRY AND PHOTOBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2013 vol. 89 p. 492 - 500

0031-8655

A major difficulty in photodynamic therapy is the poor solubility of the photosensitizer (PS) under physiological conditions which correlates with low bioavailability. PS aggregation leads to a  decrease in the photodynamic efficiency and a more limited activity in vitro and in vivo. To improve the aqueous solubility and reduce the aggregation of 2,9(10),16(17),23(24)-tetrakis[(2-dimethylamino)ethylsulfanyl]phthal-ocyaninatozinc(II) (Pc9), the encapsulation into four poloxamine polymeric micelles (T304, T904, T1107, T1307) displaying a broad spectrum of molecular weight and hydrophilic-lipophilic balance was investigated. The aqueous solubility of Pc9 was increased up to thirty times. Morphological evaluation showed the formation of Pc9-loaded spherical micelles in the nanosize range. UV/Vis and fluorescence studies indicated that Pc9 is less aggregated upon encapsulation in comparison with ZnPc in water-DMSO 2% and remained photo-stable. Pc9-loaded micelles generated singlet molecular oxygen in high yields. Photocytotoxicity assays using human nasopharynx KB carcinoma cells confirmed that the encapsulation of Pc9 in T1107 and T1307 increases its photocytotoxicity by ten times in comparison with the free form in water-DMSO.  In addition, ZnPc incorporated into cells was mainly localized in lysosomes.