Activatable 19F MRI nanoparticle probes for the detection of reducing environments

Angew Chem Int Ed Engl. 2015 Jan 12;54(3):1007-10. doi: 10.1002/anie.201409365. Epub 2014 Nov 20.


(19)F magnetic resonance imaging (MRI) probes that can detect biological phenomena such as cell dynamics, ion concentrations, and enzymatic activity have attracted significant attention. Although perfluorocarbon (PFC) encapsulated nanoparticles are of interest in molecular imaging owing to their high sensitivity, activatable PFC nanoparticles have not been developed. In this study, we showed for the first time that the paramagnetic relaxation enhancement (PRE) effect can efficiently decrease the (19)F NMR/MRI signals of PFCs in silica nanoparticles. On the basis of the PRE effect, we developed a reduction-responsive PFC-encapsulated nanoparticle probe, FLAME-SS-Gd(3+) (FSG). This is the first example of an activatable PFC-encapsulated nanoparticle that can be used for in vivo imaging. Calculations revealed that the ratio of fluorine atoms to Gd(3+) complexes per nanoparticle was more than approximately 5.0×10(2), resulting in the high signal augmentation.

Keywords: activatable probes; fluorine; imaging agents; magnetic resonance imaging; nanoparticles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Contrast Media / chemistry*
  • Coordination Complexes / chemistry
  • Fluorine-19 Magnetic Resonance Imaging*
  • Fluorocarbons / chemistry
  • Gadolinium / chemistry
  • Magnetics
  • Nanoparticles / chemistry*


  • Contrast Media
  • Coordination Complexes
  • Fluorocarbons
  • Gadolinium