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Title: {sup 1}H relaxation enhancement induced by nanoparticles in solutions: Influence of magnetic properties and diffusion

Magnetic nanoparticles that induce nuclear relaxation are the most promising materials to enhance the sensitivity in Magnetic Resonance Imaging. In order to provide a comprehensive understanding of the magnetic field dependence of the relaxation enhancement in solutions, Nuclear Magnetic Resonance {sup 1}H spin-lattice relaxation for decalin and toluene solutions of various Fe{sub 2}O{sub 3} nanoparticles was investigated. The relaxation experiments were performed in a frequency range of 10 kHz–20 MHz by applying Field Cycling method, and in the temperature range of 257–298 K, using nanoparticles differing in size and shape: spherical – 5 nm diameter, cubic – 6.5 nm diameter, and cubic – 9 nm diameter. The relaxation dispersion data were interpreted in terms of a theory of nuclear relaxation induced by magnetic crystals in solution. The approach was tested with respect to its applicability depending on the magnetic characteristics of the nanocrystals and the time-scale of translational diffusion of the solvent. The role of Curie relaxation and the contributions to the overall {sup 1}H spin-lattice relaxation associated with the electronic spin-lattice and spin-spin relaxation was thoroughly discussed. It was demonstrated that the approach leads to consistent results providing information on the magnetic (electronic) properties of the nanocrystals, i.e., effectivemore » electron spin and relaxation times. In addition, features of the {sup 1}H spin-lattice relaxation resulting from the electronic properties of the crystals and the solvent diffusion were explained.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ; ;  [5] ;  [6] ;  [7]
  1. Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn (Poland)
  2. (Germany)
  3. Department of Biophysics, Jagiellonian University Medical College, Łazarza 16, 31-530 Kraków (Poland)
  4. (Poland)
  5. Department of Physical Chemistry I, Universität Bayreuth, 95440 Bayreuth (Germany)
  6. NU-MED Group Inc., Center of Radiotherapy and Improvements in Elbląg, Królewiecka 146, 82-300 Elbląg (Poland)
  7. Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
Publication Date:
OSTI Identifier:
22252963
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CRYSTALS; DIFFUSION; FERRITES; IRON OXIDES; MAGNETIC FIELDS; MAGNETIC PROPERTIES; NANOSTRUCTURES; NMR IMAGING; NUCLEAR MAGNETIC RESONANCE; PARTICLES; SENSITIVITY; SOLUTIONS; SOLVENTS; SPIN-LATTICE RELAXATION; SPIN-SPIN RELAXATION; TEMPERATURE RANGE; TOLUENE