Particle size dependence of relaxivity for silica-coated iron oxide nanoparticles

Tanveer Ahmad, Hongsub Bae, Ilsu Rhee, Yongmin Chang, Jaejun Lee, Sungwook Hong

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

We investigate the particle size dependence of the relaxivity of hydrogen protons in an aqueous solution of iron oxide (Fe 3O 4) nanoparticles coated in silica for biocompatibility. The T 1 and T 2 relaxation times for various concentrations of silica-coated nanoparticles were determined by a magnetic resonance scanner. We find that the relaxivity increased linearly with increasing particle size. The T 2 relaxivity (R 2) is more than 50 times larger than the T 1 relaxivity (R 1) for the nanoparticle contrast agent, which reflects the fact that the T 2 relaxation is mainly influenced by outer sphere processes. The high R 2/R 1 ratio demonstrates that silica-coated iron oxide nanoparticles may serve as a T 2 contrast agents in magnetic resonance imaging with high efficacy.

Original languageEnglish
Pages (from-to)969-974
Number of pages6
JournalCurrent Applied Physics
Volume12
Issue number3
DOIs
StatePublished - May 2012

Keywords

  • Contrast agent
  • Iron oxide nanoparticle
  • MRI
  • Relaxivity
  • Silica coating

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