INVESTIGATION OF THE SUBCELLULAR-LOCALIZATION OF ZINC PHTHALOCYANINESBY RAMAN MAPPING

Raman mapping has been used to determine the subcellular distribution of two substituted zinc phthalocyanines designed for use as photosensi tizers in photodynamic therapy. Each compound was incubated over a ran ge of time periods in two cultured cell lines, and the cells were subs equently formalin-fixed for analysis. Raman spectra were recorded at 1 -2 mu m steps across the cell, with the use of 782 nm laser excitation in order to minimize absorption by the photosensitizer chromophore an d the consequent photodynamic activation of the system, Maps have been formed showing the distribution of the phthalocyanines within the cel ls. This distribution is seen to depend upon incubation time and the m olecular structure of the phthalocyanine. Similar patterns of uptake a re observed in both cell lines, Atomic forte microscopy has been used to validate the technique used to correct the maps for variations in R aman sampling volume, resulting from inhomogenous cell thickness.