Chelator-Free Radiolabeling of Nanographene: Breaking the Stereotype of Chelation

Sixiang Shi, Cheng Xu, Kai Yang, Shreya Goel, Hector F. Valdovinos, Haiming Luo, Emily B. Ehlerding, Christopher G. England, Liang Cheng, Feng Chen, Robert J. Nickles, Zhuang Liu, Weibo Cai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

50 Citations (Scopus)


Macrocyclic chelators have been widely employed in the realm of nanoparticle-based positron emission tomography (PET) imaging, whereas its accuracy remains questionable. Here, we found that 64Cu can be intrinsically labeled onto nanographene based on interactions between Cu and the π electrons of graphene without the need of chelator conjugation, providing a promising alternative radiolabeling approach that maintains the native in vivo pharmacokinetics of the nanoparticles. Due to abundant π bonds, reduced graphene oxide (RGO) exhibited significantly higher labeling efficiency in comparison with graphene oxide (GO) and exhibited excellent radiostability in vivo. More importantly, nonspecific attachment of 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) on nanographene was observed, which revealed that chelator-mediated nanoparticle-based PET imaging has its inherent drawbacks and can possibly lead to erroneous imaging results in vivo.

Original languageEnglish
Pages (from-to)2889-2892
Number of pages4
JournalAngewandte Chemie - International Edition
Issue number11
Early online date7 Feb 2017
Publication statusPublished - 6 Mar 2017
Externally publishedYes


  • graphene
  • imaging agents
  • nanoparticles
  • positron emission tomography
  • radiolabeling

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)


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