The phototoxicity of sulfonated aluminum naphthalocyanines towards V-79 Chinese hamster
cells is investigated. The disulfonated naphthalocyanine exhibits similar photostability, but better cell
penetrating properties than the tetrasulfonated dyes. The capacity of the naphthalocyanines to generate
singlet oxygen is comparable to that of the corresponding phthalocyanines. However, in contrast to
the phthalocyanine dyes, the sulfonated aluminum naphthalocyanines show very little phototoxicity
towards the V-79 cells, suggesting close association with non-vital cell constituents or extensive
formation of photoinactive adducts and aggregates