Photodynamic therapy (PDT) of cancer has been developed during the last fifteen years. Now a second generation of photosensitizers is introduced into the clinic practice whose prime advantage is higher absorption in the far-red region of the optical spectrum. Phthalocyanines (Pc) are promising representatives of this type. Sulfonated derivatives of phthalocyanine metal complexes (MeS_nPc) have been proposed for photodynamic therapy since they demonstrate a good phototoxic efficiency, are water-soluble and have a low level of dark toxicity. It was already reported that the sulfonation degree influences the photodynamic activity of MeS_nPc. Various other sensitizers are proposed for use in PDT, but still the choice of the most efficient sensitizer is mostly an empirical decision. One of the main reasons for this is the need for a clearer and deeper understanding of the relationship between the structure of the sensitizing molecule, its interaction with the cells (and tissues) and the mode and efficiency of cell death caused by subsequent photodynamic action. The present work was undertaken to investigate some aspects of this problem. We used several phthalocyanines (phthalocyanines with various degree of sulphonation, phthalocyanine adsorbed to silver sol, phthalocyanine linked to the antibody and phthalocyanine located only in the extracellular medium) to ensure different ways of internalization by the cell and studied their intracellular localization and photodynamically induced cell damage by means of confocal laser scanning microscopy, quantitative fluorescence microscopy, and flow cytometry.

Date Published: 12 January 1995
PDF: 14 pages
Proc. SPIE 2325, Photodynamic Therapy of Cancer II, (12 January 1995); doi: 10.1117/12.199145

Published in SPIE Proceedings Vol. 2325:
Photodynamic Therapy of Cancer II
Daniel Brault; Giulio Jori; Johan Moan; Benjamin Ehrenberg, Editor(s)