A ruthenium( II ) polypyridyl complex for direct imaging of DNA structure in living cells

• Published in: Nature chemistry Vol. 1; no. 8; pp. 662 - 667
• Main Authors: Battaglia, Giuseppe, Thomas, Jim A, Gill, Martin R, Garcia-Lara, Jorge, Foster, Simon J, Smythe, Carl
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2009; Nature Publishing Group
• Subjects: Analytical Chemistry; Biochemistry; Biological Transport; Cell Line, Tumor; Cell Survival; Cells; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Deoxyribonucleic acid; DNA; DNA - chemistry; Electrons; Emissions; Humans; Inorganic Chemistry; Ligands; Light; Luminescence; Metals; Microscopy; Molecular Imaging - methods; Organic Chemistry; Organometallic Compounds - chemistry; Organometallic Compounds - metabolism; Organometallic Compounds - toxicity; Physical Chemistry; Probes; Pyridines - chemistry; Ruthenium; Ruthenium - chemistry; Stains & staining; Toxicity
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.406

In the search for new biological imaging agents, metal coordination compounds able to emit from triplet metal-to-ligand charge transfer (MLCT) states offer many advantages as luminescent probes of DNA structure. However, poor cellular uptake restricts their use in live cells. Here, we present a dinuclear ruthenium( II ) polypyridyl system that works as a multifunctional biological imaging agent staining the DNA of eukaryotic and prokaryotic cells for both luminescence and transition electron microscopy. This MLCT ‘light switch’ complex directly images nuclear DNA of living cells without requiring prior membrane permeabilization. Furthermore, inhibition and transmission electron microscopy studies show this to be via a non-endocytotic, but temperature-dependent, mechanism of cellular uptake in MCF-7 cells, and confocal microscopy reveals multiple emission peaks that function as markers for cellular DNA structure. The ability to study structural changes of DNA in live cells is of considerable interest. Here, a dinuclear ruthenium ( II ) complex that acts as a multifunctional stain for DNA and its use in both luminescence and transmission electron microscopy studies is described.