Ru(II) complexes as potent photosensitizers in Photodynamic Therapy

Abstract

s / Photodiagnosis and Photodynamic Therapy 12 (2015) 325–375 339 for photodynamic therapy in cancer and a potential alternative treatment to conventional chemotherapeutics, such as cisplatin. http://dx.doi.org/10.1016/j.pdpdt.2015.07.057 Synthesis of a new bacteriochlorin derivative with long-wavelength absorption: A potential dye for use as a photosensitizer Francisco F. de Assis, Timothy J. Brocksom, Kleber T. de Oliveira Department of Chemistry, Federal University of Sao Carlos, Brazil Bacteriochlorins are very attractive candidates for use in photodynamic therapy (PDT) due to their important photophysical properties and absorption bands at the infrared region. These compounds canbeobtained fromnatural sources, suchas cyanobacteria and are denominated bacteriochlorophylls. However, the syntheses of these structures are very laborious and represent a challenge from the synthetic point of view. In our research, we have prepared a new bacteriochlorin compound, which presents a strong absorption band around 800nm. This structure was obtained by the Sonogashira cross-coupling between a tetrabromo bacteriochlorin, prepared by Lindsey’smethodology and phenylacetylene. Currently, we are evaluating the photophysical properties of this new compound as a photosensitizer for use in PDT treatment. http://dx.doi.org/10.1016/j.pdpdt.2015.07.058 Nanobody-targeted photodynamic therapy for oncology Raimond Heukers, Paul M.P. van Bergen en Henegouwen, Sabrina Oliveira Molecular Oncology, Division of Cell Biology, Department of Biology, Faculty of Science, Utrecht University, The Netherlands Monoclonal antibodies have been employed to target photosensitizers (PS) and improve tumor selectivity in photodynamic therapy (PDT). However, antibody-PS conjugates have a long blood half-life and a relatively poor tumor penetration, which result in long photosensitivity in patients and limited therapeutic efficacy. In an attempt to target PS specifically and homogenously to tumors and to accelerate PS clearance, we have developed new conjugates consisting of nanobodies targeting the epidermal growth factor receptor (EGFR) and a traceable PS (IRDye700DX). Nanobodies are the variable domain of heavy-chain antibodies existent in camelids and have a great potential in cancer imaging and therapy. The selected PS is a silicon-phthalocyanine derivative that is more hydrophilic than common PS and is suitable for nearinfrared imaging. The fluorescent nanobody-PS conjugates allow the distinction of cell lineswith different expression levels of EGFR. These conjugates specifically induce cell death of EGFR overexpressing cells, while PS alone or the nanobody-PS conjugates in absence of light induce no toxicity. Delivery of PS using internalizing biparatopic nanobody-PS conjugates results in even more pronounced toxicities. Initial in vivo studies point towards a potent therapy, enabling the combination with molecular imaging, which can have a significant impact in the field of targeted PDT. http://dx.doi.org/10.1016/j.pdpdt.2015.07.059 Ru(II) complexes as potent photosensitizers in Photodynamic Therapy