In vitro toxicity and photodynamic properties of porphyrinoids bearing imidazolium salts and N-heterocyclic carbene gold(I) complexes

International audience; Porphyrins bearing imidazolium salts were synthesized and used as N-heterocylic carbene (NHC) precursors for the preparation of gold(I) complexes. The dark toxicity and phototoxicity of the obtained compounds were investigated in vitro on MCF-7 breast cancer cells. The obtained data showed that porphyrins equipped with imidazolium salts are non-toxic in the dark and present interesting photodynamic properties. On the contrary, corresponding NHC gold(I) complexes are not suitable photosensitizers for photodynamic therapy (PDT) applications. Their dark toxicity strongly depends of the nature of the linker between the porphyrin core and the NHC. This work was extended to the synthesis of a pyropheophorbide a derivative with a pendant imidazolium group for PDT applications using excitation wavelengths of 450 nm, 545 nm, and importantly of 650 nm.