Heat generation of aqueously dispersed CoFe2O4 nanoparticles as heating agents for magnetically activated drug delivery and hyperthermia

Kim, Dong‐Hyun; Nikles, David E.; Johnson, Dylan; Brazel, Christopher S.

doi:10.1016/j.jmmm.2008.05.023

Cited by 299 publications

(144 citation statements)

References 19 publications

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“…The remanence ratios of the system under study are 0.405 and 0.349 for CoFe 2 O 4 and Co 0.8 Fe 2.2 O 4 respectively. The value of remanence ratio of 0.405 is very close to that expected (0.5) for a system of non intracting single domain particles with uniaxial anisotropy even though cobalt ferrite itself has a cubic structure (35) . The existence of an effectively uniaxial anisotropy in magnetic nanoparticles has been attributed to surface effects as evidenced by simulations of nanoparticles (36) .…”

Section: Magnetization and Hystersis Loop Studiessupporting

confidence: 80%

Phase Formation and Crystallinity-Dependent Magnetic Parameters of Co1-xFe2+xO4 Nanoparticals

Eyssa¹

2015

AJPA

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Nano crystalline cobalt ferrite CoFe 2 O 4 powders were synthesized using the coprecipitation method. The effect of the calcination temperature and the Fe 3+ /Co 2+ molar ratio on the phase formation, macro and microstructure and magnetic properties was studied systematically. The Fe 3+ /Co 2+ was controlled to equal 2 and 2.75 while the annealing temperature (T a ) was adjusted to vary from 600 to 1000C o . the obtained powders were investigated using x-ray diffraction (XRD) analysis, Field emission scanning electron microscope (FESEM), Fourir transformation infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). For both the Fe 3+ /Co 2+ ratios, the XRD results indicat the formation of well crystallized cubic spinel cobalt ferrite phase for the precursors annealed at 600C o up to 1000C o . However a second rhombohedral hematite phase whose content varies respectively from 3% and 15% was formed as the Fe 3+ /Co 2+ varied from 2 to 2.75 at T a =800 and 1000C o . The crystallite size (D β ) as determined applying the win-fit program was found also to decrease from 54.5 to 48.6nm accompanied by an increase of the root mean square strain < e g >. Using Rditveld analysis no effect on the value of the lattice parameter (a) was detected. The FESEM micrographs reveal the formation of highly agglomerated particles for Fe 3+ /Co 2+ =2.75 and T a =1000C o . The FTIR analysis confirm the formation of the spinel structure phase for both Fe 3+ /Co 2+ ratios at 1000C o , however the absorption bands shift to higher frequencies for Fe 3+ /Co 2+ =2.75. Other bands at 1663 and 3472cm -1 ascribed to free or absorbed water molecules were also detected for this ratio. The Fe 3+ /Co 2+ molar ratio was found to have a significant effect on the magnetic properties of the produced cobalt ferrite. The calculated magnetic parameters: the saturation magnetization (M S = 71.219emu/g), the coricivity (H C = 1443.8Oe) and the remanence ratio (M r /M S = 0.405) were recorded to decrease as the Fe 3+ /Co 2+ increases except for the curie temperature (T C ) which increase from 405 to 410C o .

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Section: Magnetization and Hystersis Loop Studiessupporting

confidence: 80%

Phase Formation and Crystallinity-Dependent Magnetic Parameters of Co1-xFe2+xO4 Nanoparticals

Eyssa¹

2015

AJPA

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“…In fact, for this and other reasons, the interest in this type of material for theranostic (diagnostic and therapeutic) applications is continuously increasing. 22,[27][28][29][30] On the other hand, a possible restriction to the use of some ferrites, including cobaltferrite, has to do with its potential toxicity caused by the leaching of Co atoms from the nanoparticle surface under biological environments. 22,31 Nevertheless, if such issues can be controlled, as for instance through an efficient surface passivation, this system could be interesting, especially at the non-linear regime (high magnetic fields), 6 where a larger magnetic anisotropy is expected to play a significant role.…”

Section: -mentioning

confidence: 99%

Magnetic hyperthermia investigation of cobalt ferrite nanoparticles: Comparison between experiment, linear response theory, and dynamic hysteresis simulations

Verde

Landi

Gomes

et al. 2012

Journal of Applied Physics

153

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Considerable effort has been made in recent years to optimize materials properties for magnetic hyperthermia applications. However, due to the complexity of the problem, several aspects pertaining to the combined influence of the different parameters involved still remain unclear. In this paper, we discuss in detail the role of the magnetic anisotropy on the specific absorption rate of cobalt-ferrite nanoparticles with diameters ranging from 3 to 14 nm. The structural characterization was carried out using x-ray diffraction and Rietveld analysis and all relevant magnetic parameters were extracted from vibrating sample magnetometry. Hyperthermia investigations were performed at 500 kHz with a sinusoidal magnetic field amplitude of up to 68 Oe. The specific absorption rate was investigated as a function of the coercive field, saturation magnetization, particle size, and magnetic anisotropy. The experimental results were also compared with theoretical predictions from the linear response theory and dynamic hysteresis simulations, where exceptional agreement was found in both cases. Our results show that the specific absorption rate has a narrow and pronounced maxima for intermediate anisotropy values. This not only highlights the importance of this parameter but also shows that in order to obtain optimum efficiency in hyperthermia applications, it is necessary to carefully tailor the materials properties during the synthesis process.

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“…Using similar experimental configurations but without active cooling, an initial temperature rise of the water solution at a linear rate (R W ) of 0.1-1 8C s À1 has been reported. [10] Since the energy input to heat up the water comes entirely from the heat generated in the magnetic particles, we can calculate the heating rate R IO of the IO nanoparticles in terms of R W using…”

Section: Magnetic Heating and Core Restructurementioning

confidence: 99%

Temperature‐Sensitive Nanocapsules for Controlled Drug Release Caused by Magnetically Triggered Structural Disruption

Liu

LIu

et al. 2009

Adv Funct Materials

119

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Self-assembled nanocapsules containing a hydrophilic core and a crosslinked yet thermosensitive shell have been successfully prepared using poly(ethylene-oxide)-poly(propylene-oxide)-poly(ethylene-oxide) block copolymers, 4-nitrophenyl chloroformate, gelatin, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. The core is further rendered magnetic by incorporating iron oxide nanoparticles via internal precipitation to enable externally controlled actuation under magnetic induction. The spherical nanocapsules exhibit a hydrophilic-to-hydrophobic transition at a characteristic but tunable temperature reaching 40ºC, triggering a size contraction and shrinkage of the core. The core content experiences very little leakage at 25ºC, has a half life about 5 h at 45ºC, but bursts out within a few minutes under magnetic heating due to iron oxide coarsening and core/shell disruption. Such burst-like response may be utilized for controlled drug release as illustrated here using a model drug Vitamin B12. Nanocapsules containing magnetic iron oxide (brown precipitates) and a model drug (vitamin B12) encapsulated inside a cross-linked two-layered thermosensitive PEO-PPO-PEO shell abruptly shrink above the transition temperature (40.5 8C), which dramatically increases the drug release (compare two lower curves); they also release the drug in a burst upon remote magnetic heating (upper curve).

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Heat generation of aqueously dispersed CoFe2O4 nanoparticles as heating agents for magnetically activated drug delivery and hyperthermia

Cited by 299 publications

References 19 publications

Phase Formation and Crystallinity-Dependent Magnetic Parameters of Co1-xFe2+xO4 Nanoparticals

Phase Formation and Crystallinity-Dependent Magnetic Parameters of Co1-xFe2+xO4 Nanoparticals

Magnetic hyperthermia investigation of cobalt ferrite nanoparticles: Comparison between experiment, linear response theory, and dynamic hysteresis simulations

Temperature‐Sensitive Nanocapsules for Controlled Drug Release Caused by Magnetically Triggered Structural Disruption

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