A novel luminescent Ir(iii) complex with synergistic turn-on response to hypoxia and acidity was constructed, potentially useful for early cancer detection.
Exploitation of Long-Lived <sup>3</sup>IL Excited States for Metal–Organic Photodynamic Therapy: Verification in a Metastatic Melanoma Model
作者:Richard Lincoln、Lars Kohler、Susan Monro、Huimin Yin、Mat Stephenson、Ruifa Zong、Abdellatif Chouai、Christopher Dorsey、Robie Hennigar、Randolph P. Thummel、Sherri A. McFarland
DOI:10.1021/ja408426z
日期:2013.11.13
Members of a family of Ru(II)-appended pyrenylethynylene dyads were synthesized, characterized according to their photophysical and photobiological properties, and evaluated for their collective potential as photosensitizers for metal organic photodynamic therapy. The dyads in this series possess lowest-lying (IL)-I-3-based excited states with lifetimes that can be tuned from 22 to 270 mu s in fluid solution and from 44 to 3440 mu s in glass at 77 K. To our knowledge, these excited-state lifetimes are the longest reported for Ru(II)-based dyads containing only one organic chromophore and lacking terminal diimine groups. These excited states proved to be extremely sensitive to trace amounts of oxygen, owing to their long lifetimes and very low radiative rates. Herein, we demonstrate that (IL)-I-3 states of this nature are potent photodynamic agents, exhibiting the largest photocytotoxicity indices reported to date with nanomolar light cytotoxicities at very short drug-to-light intervals. Importantly, these new agents are robust enough to maintain submicromolar PDT in pigmented metastatic melanoma cells, where the presence of melanin in combination with low oxygen tension is known to compromise PDT. This activity underscores the potential of metal organic PDT as an alternate treatment strategy for challenging environments such as malignant melanoma.