Conjugation to biocompatible dendrimers increases lanthanide T 2 relaxivity of hydroxypyridinone complexes for magnetic resonance imaging

Piper J. Klemm, William C. Floyd, Christopher M. Andolina, Jean Frechet, Kenneth N. Raymond*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Magnetic resonance imaging (MRI) contrast agents represent a worldwide billion-dollar market annually. While T 1 relaxivity enhancement contrast agents receive greater attention and a significantly larger market share, the commercial potential for T 2 relaxivity enhancing contrast agents remains a viable diagnostic option because of their increased relaxivity at high field strengths. Improvement of the contrast and biocompatibility of T 2 MRI probes may enable new diagnostic prospects for MRI. Paramagnetic lanthanides have the potential to decrease T 1 and T 2 proton relaxation times, but are not commercially used in MRI diagnostics as T 2 agents. In this article, oxygen donor chelates (hydroxypyridinone, HOPO, and terephthalamide, TAM) of various lanthanides are demonstrated as biocompatible macromolecular dendrimer conjugates for the development of T 2 MRI probes. These conjugates have relaxivities of up to 374 mM -1 s -1 per dendrimer, high bioavailability, and low in vitro toxicity. The development of high relaxivity andbiofunctional MRI probes is essential to increasing clinical diagnostic ability. T 2 MRI probes using lanthanides have the potential to increase relaxivity, biocompatibility, and offer the prospective to increase imaging modality functions.

Original languageEnglish (US)
Pages (from-to)2108-2114
Number of pages7
JournalEuropean Journal of Inorganic Chemistry
Issue number12
StatePublished - Apr 1 2012


  • Conjugation
  • Dendrimers
  • Imaging agents
  • Lanthanides
  • MRI probes

ASJC Scopus subject areas

  • Inorganic Chemistry


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