Superparamagnetic nanoparticles as high efficiency magnetic resonance imaging T2 contrast agent

Fernanda Sousa, Barbara Sanavio, Alessandra Saccani, Yun Tang, Ileana Zucca, Tamara M. Carney, Alfonso Mastropietro, Paulo H. Jacob Silva, Randy P. Carney, Kurt Schenk, Arash O. Omrani, Ping Huang, Lin Yang, Henrik M. Rønnow, Francesco Stellacci, Silke Krol

Research output: Contribution to journalArticlepeer-review


Nanoparticle-based magnetic resonance imaging T2 negative agents are of great interest, and much effort is devoted to increasing cellloading capability while maintaining low cytotoxicity. Herein, two classes of mixed-ligand protected magnetic-responsive, bimetallic gold/iron nanoparticles (Au/Fe NPs) synthesized by a two-step method are presented. Their structure, surface composition, and magnetic properties are characterized. The two classes of sulfonated Au/Fe NPs, with an average diameter of 4 nm, have an average atomic ratio of Au to Fe equal to 7 or 8, which enables the Au/Fe NPs to be superparamagnetic with a blocking temperature of 56 K and 96 K. Furthermore, preliminary cellular studies reveal that both Au/Fe NPs show very limited toxicity. MRI phantom experiments show that r2/r1 ratio of Au/Fe NPs is as high as 670, leading to a 66% reduction in T2 relaxation time. These nanoparticles provide great versatility and potential for nanoparticle-based diagnostics and therapeutic applications and as imaging contrast agents.

Original languageEnglish
Pages (from-to)161-170
Number of pages10
JournalBioconjugate Chemistry
Issue number1
Publication statusPublished - Jan 1 2017

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry


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