Book of Abstracts: Albany 2005

category image Volume 22
No. 6
June 2005

Novel DNA Detectors Based on Resonance Energy-Transfer Between Ruthenium(II) and Osmium(II) Tris(2,2'-bipyridyl) Chromophores

The creation of reliable and highly specific methods for in situ detection of nucleic acids and other biomacromolecules is crucial for development of novel approaches in genomic and post-genomic molecular diagnostic (1-3). Recently we reported the evidence of self-assembly of heterobinuclear d-f complexes in protic media, using d-block complexes as potential sensitizers, and lanthanide ions acting as potential energy acceptors (4). This approach provided a basis for potential application of visible metal-to-ligand charge-transfer (MLCT) luminescence to DNA probes, sensors and bio-assays. We report here the first example of the use of a pair of metallo-chromophores covalently attached to oligonucleotide split-probes to detect mutations and mismatches in short DNA fragments via resonance energy-transfer on target-directed assembly. Octahedral tris-chelate complexes [MII(bpy)3]2+ (M = Ru or Os, bpy = 2,2'-bipyridyl), covalently attached to the 3'- and 5'-phosphates of two oligonucleotides, are juxtaposed when hybridized contiguously to a fully complementary DNA target. Visible metal-to-ligand charge-transfer excitation of the [RuII(bpy)3]2+ unit leads to resonance energy-transfer (ET) to the MLCT state of the [OsII(bpy)3]2+ moiety. The extent of attenuation of the intense red luminescence from the RuII chromophore allows highly sensitive structural probing of the assembly and constitutes a novel approach to DNA detection and mismatch discrimination.

Figure 1: Target-directed self-assembly of the split-probe DNA system functionalized by metallochromophore parners. D and A represent the [OsII(bpy)3]2+ and [RuII(bpy)3]2+ partners attached through linkers to respective oligonucleotides via the 5' or 3' terminal phosphate groups.

References and Footnotes
  1. Wang, J. Nucleic Acids Res. 28, 3011?3016 (2000).
  2. Palecek, E. and Fojta, M. Anal. Chem. 73, 75A?83A (2001).
  3. Drummond, T. G., Hill, M. G., and Barton, J. K. Nat. Biotechnol. 21, 1192?1199 (2003).
  4. Pope, S. J. A., Coe, B. J., Faulkner, S., Bichenkova, E. V., Yu, X., and Douglas K. T. J. Am. Chem. Soc. 126, 9490?9491 (2004).

Elena V. Bichenkova1
Xuan Yu1
Pranab Bhadra1
Simon J. A. Pope2
L. Walsh1
Benjamin J. Coe2
Stephen Faulkner2
Kenneth T. Douglas1,*

1Wolfson Centre for Rational Structure-Based Design of Molecular Diagnostics
School of Pharmacy and Pharmaceutical Sciences
University of Manchester
Manchester, M13 9PL, U.K.
2School of Chemistry
University of Manchester
Oxford Road, Manchester M13 9PL, U.K.

*Corresponding author
Fax: +44 (0) 161 275 2481
Email: Ken.Douglas@.man.ac.uk