ABSTRACT
The two families of dyes that have been most extensively studied in relation to photodynamic therapy are the phthalocyanines and the porphyrins. Series of such dyes are available in a relatively pure form and are well suited for studies attempting to evaluate how the hydrophobicity of a dye influences its cellular uptake, its retention, and its photosensitizing efficiency. Derivatives of phthalocyanines and porphyrins decrease in lipophilicity as the number of sulfonate groups increases. The chapter demonstrates that the cellular uptake of the components of he-matoporphyrin derivative and PII increases with increasing lipophilicity of the components. Photoexcitation of cells containing PII results in a destruction of the binding sites of PII on proteins and a displacement of the dye molecules to other sites. A general finding for all sensitizers studied in our laboratory is that cells tend to accumulate in mitosis after being exposed to light in their presence.
