Bioorthogonal Labeling, Bioimaging, and Photocytotoxicity Studies of Phosphorescent Ruthenium(II) Polypyridine Dibenzocyclooctyne Complexes

Tommy Siu Ming Tang, Alex Man Hei Yip, Kenneth Yin Zhang, Hua Wei Liu, Po Lam Wu, King Fai Li, Kok Wai CHEAH, Kenneth Kam Wing Lo*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

25 Citations (Scopus)


The synthesis, characterization, photophysics, lipophilicity, and cellular properties of new phosphorescent ruthenium(II) polypyridine complexes functionalized with a dibenzocyclooctyne (DIBO) or amine moiety [Ru(N^N)2(L)](PF6)2 are reported (L=4-(13-N-(3,4:7,8-dibenzocyclooctyne-5-oxycarbonyl) amino-4,7,10-trioxa-tridecanyl-aminocarbonyl-oxy-methyl)-4′-methyl-2,2′-bipyridine bpy-DIBO, N^N=2,2′-bipyridine bpy (1a), 1,10-phenanthroline phen (2a); L=4-(13-amino-4,7,10-trioxa-tridecanylaminocarbonyl-oxy-methyl)-4′-methyl-2,2′-bipyridine bpy-NH2, N^N=bpy (1b), phen (2b)). The strain-promoted alkyne-azide cycloaddition (SPAAC) reaction of the DIBO complexes 1a and 2a with benzyl azide were studied. Also, the DIBO complexes 1a and 2a can selectively label N-azidoglycans located on the surface of CHO-K1 and A549 cells that were pretreated with 1,3,4,6-tetra-O-acetyl-N-azidoacetyl-D-mannosamine (Ac4ManNAz). Additionally, the intracellular trafficking and localization of these biomolecules were monitored using laser-scanning confocal microscopy. Interestingly, the biolabeling and cellular uptake efficiency of the DIBO complexes 1a and 2a were cell-line dependent, as revealed by flow cytometry and ICP-MS. Furthermore, the complexes showed good biocompatibility toward the Ac4ManNAz-pretreated cells in the dark, but exhibited photoinduced cytotoxicity due to the generation of singlet oxygen. Tracing of cell-surface glycans: New azide-reactive phosphorescent ruthenium(II) polypyridine dibenzocyclooctyne (DIBO) complexes were designed to selectively label and visualize N-azidoglycans of 1,3,4,6-tetra-O-acetyl-N-azidoacetyl-D-mannosamine (Ac4ManNAz)-pretreated cells (see figure).

Original languageEnglish
Pages (from-to)10729-10740
Number of pages12
JournalChemistry - A European Journal
Issue number30
Publication statusPublished - 1 Jul 2015

Scopus Subject Areas

  • Catalysis
  • Organic Chemistry

User-Defined Keywords

  • bioorthogonal labeling
  • cell-surface glycan recycling
  • imaging agents
  • photocytotoxicity
  • ruthenium


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