The influence of collective behavior on the magnetic and heating properties of iron oxide nanoparticles

C. L. Dennis; A. J. Jackson; J. A. Borchers; R. Ivkov; A. R. Foreman; J. W. Lau; E. Goernitz; C. Gruettner

doi:10.1063/1.2837647

The influence of collective behavior on the magnetic and heating properties of iron oxide nanoparticles

C. L. Dennis, A. J. Jackson, J. A. Borchers, R. Ivkov, A. R. Foreman, J. W. Lau, E. Goernitz, C. Gruettner

Research output: Contribution to journal › Article › peer-review

80 Scopus citations

Abstract

Magnetic nanoparticles with a high specific absorption rate (SAR) have been developed and used in mouse models of cancer. The magnetic nanoparticles are comprised of predominantly iron oxide magnetic cores surrounded by a dextran layer for colloidal stability. The average diameter of a single particle (core plus dextran) is 92±14 nm as measured by photon correlation spectroscopy. Small angle neutron scattering measurements under several H2 O D2 O contrast conditions and at varying nanoparticle concentrations have revealed three length scales: >10 μm, several hundred nanometers, and tens of nanometers. The latter corresponds to the particle diameter; the several hundred nanometers corresponds to a hard sphere interaction radius of the core/shell nanoparticles; >10 μm corresponds to the formation of long-range, many-particle structures held together by magnetic interactions and dextran. The long-range collective magnetic behavior appears to play a major role in enhancing the SAR. For samples having nominally equal concentrations and similar saturation magnetizations, the measured SAR is 1075 W /(g of Fe) for tightly associated nanoparticles and 150 W /(g of Fe) for very loosely associated nanoparticles at an applied field of 86 kAm (1080 Oe) and 150 kHz.

Original language	English (US)
Article number	07A319
Journal	Journal of Applied Physics
Volume	103
Issue number	7
DOIs	https://doi.org/10.1063/1.2837647
State	Published - 2008
Externally published	Yes

ASJC Scopus subject areas

Physics and Astronomy(all)

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title = "The influence of collective behavior on the magnetic and heating properties of iron oxide nanoparticles",

abstract = "Magnetic nanoparticles with a high specific absorption rate (SAR) have been developed and used in mouse models of cancer. The magnetic nanoparticles are comprised of predominantly iron oxide magnetic cores surrounded by a dextran layer for colloidal stability. The average diameter of a single particle (core plus dextran) is 92±14 nm as measured by photon correlation spectroscopy. Small angle neutron scattering measurements under several H2 O D2 O contrast conditions and at varying nanoparticle concentrations have revealed three length scales: >10 μm, several hundred nanometers, and tens of nanometers. The latter corresponds to the particle diameter; the several hundred nanometers corresponds to a hard sphere interaction radius of the core/shell nanoparticles; >10 μm corresponds to the formation of long-range, many-particle structures held together by magnetic interactions and dextran. The long-range collective magnetic behavior appears to play a major role in enhancing the SAR. For samples having nominally equal concentrations and similar saturation magnetizations, the measured SAR is 1075 W /(g of Fe) for tightly associated nanoparticles and 150 W /(g of Fe) for very loosely associated nanoparticles at an applied field of 86 kAm (1080 Oe) and 150 kHz.",

author = "Dennis, {C. L.} and Jackson, {A. J.} and Borchers, {J. A.} and R. Ivkov and Foreman, {A. R.} and Lau, {J. W.} and E. Goernitz and C. Gruettner",

note = "Funding Information: This work is supported by the U.S. Army Medical Research and Materiel Command under Contract No. W81XWH-04-C-0142. The views, opinions, and/or findings contained in the report are those of the author(s) and should not be construed as an official Department of the Army position, policy, or decision unless so designated by other documentation. This work utilized facilities supported in part by the National Science Foundation under Agreement No. DMR-0454672.",

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doi = "10.1063/1.2837647",

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journal = "Journal of Applied Physics",

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AU - Dennis, C. L.

AU - Jackson, A. J.

AU - Borchers, J. A.

AU - Ivkov, R.

AU - Foreman, A. R.

AU - Lau, J. W.

AU - Goernitz, E.

AU - Gruettner, C.

N1 - Funding Information: This work is supported by the U.S. Army Medical Research and Materiel Command under Contract No. W81XWH-04-C-0142. The views, opinions, and/or findings contained in the report are those of the author(s) and should not be construed as an official Department of the Army position, policy, or decision unless so designated by other documentation. This work utilized facilities supported in part by the National Science Foundation under Agreement No. DMR-0454672.

PY - 2008

Y1 - 2008

N2 - Magnetic nanoparticles with a high specific absorption rate (SAR) have been developed and used in mouse models of cancer. The magnetic nanoparticles are comprised of predominantly iron oxide magnetic cores surrounded by a dextran layer for colloidal stability. The average diameter of a single particle (core plus dextran) is 92±14 nm as measured by photon correlation spectroscopy. Small angle neutron scattering measurements under several H2 O D2 O contrast conditions and at varying nanoparticle concentrations have revealed three length scales: >10 μm, several hundred nanometers, and tens of nanometers. The latter corresponds to the particle diameter; the several hundred nanometers corresponds to a hard sphere interaction radius of the core/shell nanoparticles; >10 μm corresponds to the formation of long-range, many-particle structures held together by magnetic interactions and dextran. The long-range collective magnetic behavior appears to play a major role in enhancing the SAR. For samples having nominally equal concentrations and similar saturation magnetizations, the measured SAR is 1075 W /(g of Fe) for tightly associated nanoparticles and 150 W /(g of Fe) for very loosely associated nanoparticles at an applied field of 86 kAm (1080 Oe) and 150 kHz.

AB - Magnetic nanoparticles with a high specific absorption rate (SAR) have been developed and used in mouse models of cancer. The magnetic nanoparticles are comprised of predominantly iron oxide magnetic cores surrounded by a dextran layer for colloidal stability. The average diameter of a single particle (core plus dextran) is 92±14 nm as measured by photon correlation spectroscopy. Small angle neutron scattering measurements under several H2 O D2 O contrast conditions and at varying nanoparticle concentrations have revealed three length scales: >10 μm, several hundred nanometers, and tens of nanometers. The latter corresponds to the particle diameter; the several hundred nanometers corresponds to a hard sphere interaction radius of the core/shell nanoparticles; >10 μm corresponds to the formation of long-range, many-particle structures held together by magnetic interactions and dextran. The long-range collective magnetic behavior appears to play a major role in enhancing the SAR. For samples having nominally equal concentrations and similar saturation magnetizations, the measured SAR is 1075 W /(g of Fe) for tightly associated nanoparticles and 150 W /(g of Fe) for very loosely associated nanoparticles at an applied field of 86 kAm (1080 Oe) and 150 kHz.

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The influence of collective behavior on the magnetic and heating properties of iron oxide nanoparticles

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