Organic radical contrast agents for magnetic resonance imaging

Andrzej Rajca, Ying Wang, Michael Boska, Joseph T. Paletta, Arnon Olankitwanit, Michael A. Swanson, Deborah G. Mitchell, Sandra S. Eaton, Gareth R. Eaton, Suchada Rajca

Research output: Contribution to journalArticlepeer-review

155 Scopus citations


We report a molecular design that provides an intravenously injectable organic radical contrast agent (ORCA) for which the molecular 1H water relaxivity (r1) is ca. 5 mM-1 s-1. The ORCA is based on spirocyclohexyl nitroxide radicals and poly(ethylene glycol) chains conjugated to a fourth-generation polypropylenimine dendrimer scaffold. The metal-free ORCA has a long shelf life and provides selectively enhanced magnetic resonance imaging in mice for over 1 h.

Original languageEnglish (US)
Pages (from-to)15724-15727
Number of pages4
JournalJournal of the American Chemical Society
Issue number38
StatePublished - Sep 26 2012

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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