Joint Study on the Development of New PDT Photosensitizers

点击翻译按钮获取中文摘要

Photodynamic therapy (PDT) of cancer utilizing photosensitizers has been widely investigated. Though hematoporphyrin derivatives (HpD) have been used for PDT,they absorb little light of longer wavelengths (above 600 nm) which have good tissue penetration. In this study we synthesized zinc phthalocyanines with different degree of sulfonation, ZnTSPc and ZnSPc_<mix> and compared their tumor uptake, affinity to protein and phototoxicity.HeLa cells were incubated with both ZnTSPc and ZnSPc_<mix> solutions. Solutions were then removed and cells were washed with fresh medium followed by addition of 0.1 N NaOH.The maxima at 680 nm were observed especially in the case of ZnSPc_<mix>. This indicates that cellular uptake of ZnSPc_<mix> was better than that of ZnTSPc. It is concluded that ZnSPc_<mix> is more easily dissociated in cells than ZnTSPc.HeLa cells were irradiated by DCM dye laser after incubation with F-10 medium containing ZnTSPc or ZnSPc_<mix>. After irradiation, the trypan blue meth … More od was carried out. In the case of ZnTSPc, phototoxicity decreased with decreasing irradiation energy. In comparison, the phototoxicity by ZnSPc_<mix> was observed even at low dye concentration. Though the dye concentration and irradiation energy were low, HeLa Cells were damaged by irradiation with ZnSPc_<mix>. From the above results, ZnSPc_<mix> is a better sensitizer for PDT than ZnTSPc.Properties of zinc phthalocyanines sulfonated to difierent degrees were studied as sensitizers for PDT.From the spectrofluorometric analysis, ZnSPc_<mix> was incorporated in cells better than ZnTSPc. It was also clear that the affinity of ZnSPc_<mix> with serum proteins was higher than that of ZnTSPc. PDT experiment showed that cells were damaged by ZnSPc_<mix> even at low concentration and irradiation energy. Observation of the cell-dying process by SEM showed a large difference between cellular morphological changes by both compounds. This behavior of ZnSPc_<mix> depends on the increase of its penetration into cells due to the increase of its hydrophobicity. Less