| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1315936 | Journal of Inorganic Biochemistry | 2014 | 9 Pages |
•Ru polypyridyl complex with 2-nitroimidazole moiety is a potential theranostic agent.•Luminescence properties of Ru complex are markedly increased in oxygen-free solution.•The interaction of Ru complex with albumin enhances its luminescence properties.•Luminescence expressed by cells linearly increases with applied Ru concentration.•Ru complex is quite cytotoxic with LD50 of 10 μM.
A novel long-lifetime highly luminescent ruthenium polypyridyl complex containing 2-nitroimidazole moiety [Ru(dip)2(bpy-2-nitroIm)]Cl2 (dip = 4,7-diphenyl-1,10-phenanthroline, bpy-2-nitroIm = 4-[3-(2-nitro-1H-imidazol-1-yl)propyl]-2,2′-bipyridine) has been designed cancer treatment and imaging. The luminescence properties of the synthesized compound strongly depend on the oxygen concentration. Under oxygen-free conditions quantum yield of luminescence and the average lifetime of emission were found to be 0.034 and 1.9 μs, respectively, which is ca. three times higher in comparison to values obtained in air-equilibrated solution. The binding properties of the investigated ruthenium complex to human serum albumin have been studied and the apparent binding constant for the formation of the protein-ruthenium adduct was determined to be 1.1 × 105 M− 1. The quantum yield and the average lifetime of emission are greatly enhanced upon binding of ruthenium compound to the protein. The DNA binding studies revealed two distinguished binding modes which lead to a decrease in luminescence intensity of ruthenium complex up to 60% for [DNA]/[Ru] < 2, and enhancement of emission for [DNA]/[Ru] > 80. Preliminary biological studies confirmed fast and efficient accumulation of the ruthenium complex inside cells. Furthermore, the ruthenium complex was found to be relatively cytotoxic with LD50 of 12 and 13 μM for A549 and CT26 cell lines, respectively, under normoxic conditions. The retention and cellular uptake of ruthenium complex is enhanced under hypoxic conditions and its LD50 decreases to 8 μM for A549 cell line.
Graphical abstractRu(II) complex bearing two 4,7-diphenyl-1,10-phenanthroline ligands and 2,2′-bipyridine anchoring 2-nitroimidazole was designed towards its application in treatment and visualization of cancer.Figure optionsDownload full-size imageDownload as PowerPoint slide
