Phthalocyanine-Biomolecule Conjugated Photosensitizers for Targeted Photodynamic Therapy and Imaging

Photodynamic therapy (PDT) is now in clinical practice in many European and American countries as a minimally invasive therapeutic technique to treat oncologic malignancies and other nononcologic conditions. Phthalocyanines (Pcs) are gathering importance as effective photosensitizers in targeted PDT and imaging of tumors. The possibility of modification around the Pc macrocycle led the researchers to the synthesis of a diversity of photosensitizers with varied cell specificity, cellular internalization and localization, photodynamic cytotoxicity and excretion. Cellular targeting is the primary aspect of an ideal photosensitizer for targeting PDT. Therefore, Pcs have been structurally modified with a variety of biomolecules capable of recognizing the specific lesions. This review emphasizes the photocytotoxicity and the cellular uptakes of phthalocyanine photosensitizers conjugated with biomolecules including carbohydrates, nucleotides and protein constituents such as amino acids and peptides. In addition, the role of the Pc-biomolecule conjugates in imaging and antimicrobial chemotherapy has been discussed.