Compact zwitterion-coated iron oxide nanoparticles for biological applications

He Wei, Numpon Insin, Jungmin Lee, Hee Sun Han, Jose M. Cordero, Wenhao Liu, Moungi G. Bawendi

Research output: Contribution to journalArticlepeer-review


The potential of superparamagnetic iron oxide nanoparticles (SPIONs) in various biomedical applications, including magnetic resonance imaging (MRI), sensing, and drug delivery, requires that their surface be derivatized to be hydrophilic and biocompatible. We report here the design and synthesis of a compact and water-soluble zwitterionic dopamine sulfonate (ZDS) ligand with strong binding affinity to SPIONs. After ligand exchange, the ZDS-coated SPIONs exhibit small hydrodynamic diameters, and stability with respect to time, pH, and salinity. Furthermore, small ZDS coated SPIONs were found to have a reduced nonspecific affinity (compared to negatively charged SPIONs) toward serum proteins; streptavidin/dye functionalized SPIONs were bioactive and thus specifically targeted biotin receptors.

Original languageEnglish (US)
Pages (from-to)22-25
Number of pages4
JournalNano letters
Issue number1
StatePublished - Jan 11 2012
Externally publishedYes


  • Superparamagnetic iron oxide nanoparticles
  • biotin labeling
  • hydrodynamic diameter
  • serum binging test
  • stability
  • zwitterionic dopamine sulfonate

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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