Functionalization and peptide-based delivery of magnetic nanoparticles as an intracellular MRI contrast agent

N. Nitin, L. E W LaConte, O. Zurkiya, X. Hu, G. Bao

Research output: Contribution to journalArticlepeer-review

274 Scopus citations


We report the development of functionalized superparamagnetic iron oxide nanoparticles with a PEG-modified, phospholipid micelle coating, and their delivery into living cells. The size of the coated particles, as determined by dynamic light scattering and electron microscopy, was found to be between 12 and 14 nm. The PEG-phospholipid coating resulted in high water solubility and stability, and the functional groups of modified PEG allowed for bioconjugation of various moieties, including a fluorescent dye and the Tat peptide. Efficient delivery of the functionalized nanoparticles into living cells was confirmed by fluorescence microscopy, relaxation time measurements, and magnetic resonance imaging (MRI). This demonstrates the feasibility of using functionalized magnetic nanoparticles with uniform (∼10 nm) sizes as an MRI contrast agent for intracellular molecular imaging in deep tissue. These micelle-coated iron oxide nanoparticles offer a versatile platform for conjugation of a variety of moieties, and their small size confers advantages for intracellular molecular imaging with minimal perturbation.

Original languageEnglish (US)
Pages (from-to)706-712
Number of pages7
JournalJournal of Biological Inorganic Chemistry
Issue number6
StatePublished - Sep 2004
Externally publishedYes


  • Cell penetrating peptide
  • Cellular delivery
  • Contrast agents
  • Magnetic resonance imaging
  • Superparamagnetic nanoparticles

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry


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