Synthesis, characterisation and bioimaging of a fluorescent rhenium-containing PNA bioconjugate

Dalton Trans. 2012 Feb 28;41(8):2304-13. doi: 10.1039/c2dt12114j. Epub 2011 Dec 20.

Abstract

A new rhenium tricarbonyl complex of a bis(quinoline)-derived ligand (2-azido-N,N-bis((quinolin-2-yl)methyl)ethanamine, L-N(3)), namely [Re(CO)(3)(L-N(3))]Br was synthesized and characterized in-depth, including by X-ray crystallography. [Re(CO)(3)(L-N(3))]Br exhibits a strong UV absorbance in the range 300-400 nm with a maximum at 322 nm, and upon photoexcitation, shows two distinct emission bands at about 430 and 560 nm in various solvents (water, ethylene glycol). [Re(CO)(3)(L-N(3))]Br could be conjugated, on a solid phase, to a peptide nucleic acid (PNA) oligomer using the copper(I)-catalyzed azide-alkyne cycloaddition reaction (Cu-AAC, "click" chemistry) and an alkyne-containing PNA building block to give Re-PNA. It was demonstrated that upon hybridisation with a complementary DNA strand (DNA), the position of the maxima and emission intensity for the hybrid Re-PNA·DNA remained mainly unchanged compared to those of the single strand Re-PNA. The rhenium-containing PNA oligomer Re-PNA could be then mediated in living cells where they have been shown to be non-toxic contrary to the general notion that organometallic compounds are usually unstable under physiological conditions and/or cytotoxic. Furthermore, Re-PNA could be detected in living cells using fluorescent microscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Survival
  • Chemistry Techniques, Synthetic / methods*
  • Crystallography, X-Ray
  • DNA / chemistry
  • DNA / genetics
  • Fluorescent Dyes / chemical synthesis*
  • Fluorescent Dyes / chemistry
  • Fluorescent Dyes / metabolism
  • HeLa Cells
  • Humans
  • Microscopy, Fluorescence
  • Molecular Imaging / methods*
  • Organometallic Compounds / chemistry
  • Peptide Nucleic Acids / chemical synthesis*
  • Peptide Nucleic Acids / chemistry
  • Peptide Nucleic Acids / metabolism
  • Quinolines / chemistry
  • Rhenium / chemistry*
  • Spectrum Analysis
  • Temperature

Substances

  • Fluorescent Dyes
  • Organometallic Compounds
  • Peptide Nucleic Acids
  • Quinolines
  • Rhenium
  • DNA