title: Synthesis, characterisation and bioimaging of a fluorescent rhenium-containing PNA bioconjugate.
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.
authors.affiliation: Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland. gilles.gasser@aci.uzh.ch
authors.forename: Gilles
authors.initials: G
authors.lastname: Gasser
authors.forename: Antonio
authors.initials: A
authors.lastname: Pinto
authors.forename: Sebastian
authors.initials: S
authors.lastname: Neumann
authors.forename: Anna M
authors.initials: AM
authors.lastname: Sosniak
authors.forename: Michael
authors.initials: M
authors.lastname: Seitz
authors.forename: Klaus
authors.initials: K
authors.lastname: Merz
authors.forename: Rolf
authors.initials: R
authors.lastname: Heumann
authors.forename: Nils
authors.initials: N
authors.lastname: Metzler-Nolte
mesh_terms: D001483:Base Sequence; D002470:Cell Survival; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000235:genetics; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000737:chemistry; D020135:Peptide Nucleic Acids / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D011804:Quinolines / Q000737:chemistry; D012211:Rhenium / Q000737:chemistry*; D013057:Spectrum Analysis; D013696:Temperature
chemical_list: D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D020135:Peptide Nucleic Acids; D011804:Quinolines; D012211:Rhenium; D004247:DNA