Influence of cobalt doping on the hyperthermic efficiency of magnetite nanoparticles

Fantechi, Elvira; Innocenti, Claudia; Albino, Martin; Lottini, Elisabetta; Sangregorio, Claudio

doi:10.1016/j.jmmm.2014.10.082

Cited by 109 publications

(76 citation statements)

References 34 publications

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“…Although a direct relation between reflux times and sizes is not observed, in good agreement with data in the literature [16,29], the shape of the nanoparticles certainly depends on that time. At low reaction times spherical nanoparticles appear and, at increasing reaction times, nanocubes and, by prolonging the reaction time, spheric/cuboctahedral nanoparticles appear.…”

Section: Resultssupporting

confidence: 89%

“…Nanoparticles with nominal composition x = 0.15 present cobalt contents in the 0.08–0.16 range. A deficiency of cobalt has been previously established in similar ferrite nanoparticles prepared with oleic acid (OA), oleylamine (OLA), and 1,2-hexadecanediol (HDD) as surfactants [16]. In fact, Crouse et al determined that modifying different synthesis parameters, such as the co-surfactant or the proportion of metallic precursors, the incorporation of cobalt cations into the ferrite lattice could be modified, although a steady reduction in Co content in all analyzed compositions was observed [17].…”

Section: Resultsmentioning

confidence: 99%

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Exploring Reaction Conditions to Improve the Magnetic Response of Cobalt-Doped Ferrite Nanoparticles

et al. 2018

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With the aim of studying the influence of synthesis parameters in structural and magnetic properties of cobalt-doped magnetite nanoparticles, Fe3−xCoxO4 (0 < x < 0.15) samples were synthetized by thermal decomposition method at different reaction times (30–120 min). The Co ferrite nanoparticles are monodisperse with diameters between 6 and 11 nm and morphologies depending on reaction times, varying from spheric, cuboctahedral, to cubic. Chemical analysis and X-ray diffraction were used to confirm the composition, high crystallinity, and pure-phase structure. The investigation of the magnetic properties, both magnetization and electronic magnetic resonance, has led the conditions to improve the magnetic response of doped nanoparticles. Magnetization values of 86 emu·g−1 at room temperature (R.T.) have been obtained for the sample with the highest Co content and the highest reflux time. Magnetic characterization also displays a dependence of the magnetic anisotropy constant with the varying cobalt content.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Exploring Reaction Conditions to Improve the Magnetic Response of Cobalt-Doped Ferrite Nanoparticles

et al. 2018

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“…While TD NPs exhibit a much larger K EFF and a narrower χ IRR (H), SV NPs show a broader χ IRR (H) and a lower anisotropy. Although a 10–15% increase is expected in K EFF when the Co fraction decreases from 1 to 0.7 in Co‐substituted magnetite, such variation in the composition is not enough to explain the large difference between K EFF values from thermal decomposition and solvothermal methods, particularly considering that the NPs have a comparable size. It is more likely that the ligands‐controlled synthesis is promoting a higher anisotropy by favoring an increased structural coherence and a lower density of defects, as pointed out in the previous section.…”

Section: Resultsmentioning

confidence: 97%

“…Such differences are, however, not unexpected since Co(acac) 2 and Fe(acac) 3 are decomposing at different temperatures and this can lead to variations in the stoichiometry . The decrease in the amount of Co 2+ ions could lead to the formation of vacancies or to the introduction of Fe 2+ in the spinel structure . This will be considered further below when analyzing the results from Mössbauer spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Internal Structure and Magnetic Properties in Cobalt Ferrite Nanoparticles: Influence of the Synthesis Method

Lavorato

Alzamora

Contreras

et al. 2019

Part & Part Syst Charact

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The design of novel nanostructured magnetic materials requires a good understanding of the variation in the magnetic properties due to different synthesis conditions. In this work, four different procedures for fabricating Co‐ferrite nanoparticles with similar sizes between 7 and 10 nm are compared by studying their structural and magnetic properties. Non‐aqueous methods based on the thermal decomposition of metal acetylacetonates at high temperatures, either with or without surfactants, provide highly crystalline nanoparticles with large saturation magnetization values and a coherent reversal of the magnetic moment. However, variations in the density of defects and in the shape of the nanocrystals determine the distribution of switching fields and the effective magnetic anisotropy, which reaches up to ≈1 × 107 erg cm−3 for oleic acid‐capped 9 nm nanoparticles. It is shown that the saturation magnetization values for nanoparticles produced by different methods are in the range between 49 and 95 emu g−1 due to differences in the stoichiometry, in the cation occupancy, in the magnetic disorder and in the spin canting of the magnetic sub‐lattices, the latter evaluated by in‐field Mössbauer spectroscopy.

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“…These particles’ magnetic response to an external magnetic field depends on properties such as their size, core composition and surface coating. Modifying their composition by doping transition metal cations into the iron oxides cores alters the nanoparticles’ magnetic moments89 and magnetic anisotropies101112. By altering these two key properties the response of the nanoparticles to an external magnetic field can be defined.…”

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confidence: 99%

The cellular magnetic response and biocompatibility of biogenic zinc- and cobalt-doped magnetite nanoparticles

Moise

Céspedes

Soukup

et al. 2017

Sci Rep

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The magnetic moment and anisotropy of magnetite nanoparticles can be optimised by doping with transition metal cations, enabling their properties to be tuned for different biomedical applications. In this study, we assessed the suitability of bacterially synthesized zinc- and cobalt-doped magnetite nanoparticles for biomedical applications. To do this we measured cellular viability and activity in primary human bone marrow-derived mesenchymal stem cells and human osteosarcoma-derived cells. Using AC susceptibility we studied doping induced changes in the magnetic response of the nanoparticles both as stable aqueous suspensions and when associated with cells. Our findings show that the magnetic response of the particles was altered after cellular interaction with a reduction in their mobility. In particular, the strongest AC susceptibility signal measured in vitro was from cells containing high-moment zinc-doped particles, whilst no signal was observed in cells containing the high-anisotropy cobalt-doped particles. For both particle types we found that the moderate dopant levels required for optimum magnetic properties did not alter their cytotoxicity or affect osteogenic differentiation of the stem cells. Thus, despite the known cytotoxicity of cobalt and zinc ions, these results suggest that iron oxide nanoparticles can be doped to sufficiently tailor their magnetic properties without compromising cellular biocompatibility.

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Influence of cobalt doping on the hyperthermic efficiency of magnetite nanoparticles

Cited by 109 publications

References 34 publications

Exploring Reaction Conditions to Improve the Magnetic Response of Cobalt-Doped Ferrite Nanoparticles

Exploring Reaction Conditions to Improve the Magnetic Response of Cobalt-Doped Ferrite Nanoparticles

Internal Structure and Magnetic Properties in Cobalt Ferrite Nanoparticles: Influence of the Synthesis Method

The cellular magnetic response and biocompatibility of biogenic zinc- and cobalt-doped magnetite nanoparticles

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