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Title: Effect of spatial confinement on magnetic hyperthermia via dipolar interactions in Fe3O4 nanoparticles for biomedical applications

In this work, the effect of nanoparticle confinement on the magnetic relaxation of iron oxide (Fe3O4) nanoparticles (NP) was investigated by measuring the hyperthermia heating behavior in high frequency alternating magnetic field. Three different Fe3O4 nanoparticle systems having distinct nanoparticle configurations were studied in terms of magnetic hyperthermia heating rate and DC magnetization. All magnetic nanoparticle (MNP) systems were constructed using equivalent ~10nm diameter NP that were structured differently in terms of configuration, physical confinement, and interparticle spacing. The spatial confinement was achieved by embedding the Fe3O4 nanoparticles in the matrices of the polystyrene spheres of 100 nm, while the unconfined was the free Fe3O4 nanoparticles well-dispersed in the liquid via PAA surface coating. Assuming the identical core MNPs in each system, the heating behavior was analyzed in terms of particle freedom (or confinement), interparticle spacing, and magnetic coupling (or dipole-dipole interaction). DC magnetization data were correlated to the heating behavior with different material properties. Analysis of DC magnetization measurements showed deviation from classical Langevin behavior near saturation due to dipole interaction modification of the MNPs resulting in a high magnetic anisotropy. It was found that the Specific Absorption Rate (SAR) of the unconfined nanoparticle systems were significantly higher thanmore » those of confined (the MNPs embedded in the polystyrene matrix). This increase of SAR was found to be attributable to high Néel relaxation rate and hysteresis loss of the unconfined MNPs. It was also found that the dipole-dipole interactions can significantly reduce the global magnetic response of the MNPs and thereby decrease the SAR of the nanoparticle systems.« less
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [1] ;  [1] ;  [1]
  1. University of Cincinnati
  2. Ames Laboratory
  3. Stanford University
  4. Shanghai Jiao Tong University
  5. Tongji University School of Medicine
Publication Date:
OSTI Identifier:
Report Number(s):
IS-J 8459
Journal ID: ISSN 0928-4931
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Science and Engineering. C, Biomimetic Materials, Sensors and Systems; Journal Volume: 42
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
36 MATERIALS SCIENCE Dipole interaction; Fe(3)O(4) nanoparticles; Magnetic anisotropy; Néel relaxation; Superparamagnetism