PEGylation of Terminal Ligands as a Route to Decrease the Toxicity of Radiocontrast Re-Clusters.

The development of novel radiocontrast agents, mainly used for the visualization of blood vessels, is still an emerging task due to the variety of side effects of conventional X-ray contrast media. Recently, we have shown that octahedral chalcogenide rhenium clusters with phosphine ligands-NaH[{ReQ}(P(CHCOO))] (Q = S, Se)-can be considered as promising X-ray contrast agents if their relatively high toxicity related to the high charge of the complexes can be overcome. To address this issue, we propose one of the most widely used methods for tuning the properties of proteins and peptides-PEGylation (PEG is polyethylene glycol).

A water-soluble octahedral molybdenum cluster complex as a potential agent for X-ray induced photodynamic therapy.

X-ray-induced photodynamic therapy (X-PDT) has recently evolved into a suitable modality to fight cancer. This technique, which exploits radiosensitizers producing reactive oxygen species, allows for a reduction of the radiation dose needed to eradicate cancer in the frame of the radiotherapy treatment of deep tumors. The use of transition metal complexes able to directly produce singlet oxygen, O(Δ), upon X-ray irradiation constitutes a promising route towards the optimization of the radiosensitizer's architecture.