Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated MnxFe1-xO nanoparticles

Wei Chen, Fang Lu, Chiao Chi V. Chen, Kuan Chi Mo, Yann Hung, Zhi Xuan Guo, Chia Hui Lin, Ming Huang Lin, Yu Hsuan Lin, Chen Chang, Chung Yuan Mou

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2-RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities. In vivo MRI of rats injected intravenously with MIO@SiO2-RITC nanoparticles exhibited enhancement of the T1 contrast in brain tissue, in particular a time-delayed enhancement in the hippocampus, pituitary gland, striatum and cerebellum. This is attributable to the gradual degradation of MIO@SiO2-RITC nanoparticles in the liver, resulting in the slow release of manganese(II) [Mn(II)] into the blood pool and, subsequently, accumulation in the brain tissue. Thus, T1-weighted contrast enhancement was clearly detected in the anatomic structure of the brain as time progressed. In addition, T2z.ast;-weighted images of the liver showed a gradual darkening effect. Here, we demonstrate the concept of the slow release of Mn(II) for neuroimaging. This new nanoparticle-based manganese contrast agent allows one simple intravenous injection (rather than multiple infusions) of Mn(II) precursor, and results in delineation of the detailed anatomic neuroarchitecture in MRI; hence, this provides the advantage of the long-term study of neural function.

Original languageEnglish
Pages (from-to)1176-1185
Number of pages10
JournalNMR in Biomedicine
Issue number9
Publication statusPublished - Sept 2013
Externally publishedYes


  • Brain image
  • Imaging agent
  • Magnetic nanoparticle
  • Manganese
  • Neuroarchitecture
  • Silica sphere
  • Slow release

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy


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