Photodynamic Therapy of Cancer

Photodynamic therapy (PDT) is a binary modality for cancer treatment that involves the activation of photosensitizer-containing tissue with light. Since neither the photosensitizer nor the light has a toxic effect when used alone, PDT has the potential for being highly selective for tumor tissue. Phthalocyanines are promising photosensitizers for use in PDT because they typically exhibit strong light absorptions in the near-infrared and often have high quantum yields of singlet oxygen formation. We have synthesized two Zn−Pc−peptide conjugates bearing either a short linker or a long PEG−linker between the macrocycle and a bifunctional peptide containing the nucleoplasmin and HIV-1 Tat 48−60 sequences in order to increase the Pc cell-targeting ability and to evaluate the effect of the linker. Both conjugates were found to localized preferentially within the cell lysosomes. Bioconjugate Chem., 2007, 18 (2), 410–420.