Size-dependent magnetic and inductive heating properties of Fe₃O₄ nanoparticles: scaling laws across the superparamagnetic size

Abstract

An efficient heat activating mediator with an enhanced specific absorption rate (SAR) value is attained via control of the iron oxide (Fe3O4) nanoparticle size from 3 to 32 nm. Monodispersed Fe3O4 nanoparticles are synthesized via a seed-less thermolysis technique using oleylamine and oleic acid as the multifunctionalizing agents (surfactant, solvent and reducing agent). The inductive heating properties as a function of particle size reveal a strong increase in the SAR values with increasing particle size up to 28 nm. In particular, the SAR values of ferromagnetic nanoparticles (>16 nm) are strongly enhanced with the increase of ac magnetic field amplitude than that for the superparamagnetic (3-16 nm) nanoparticles. The enhanced SAR values in the ferromagnetic regime are attributed to the synergistic contribution from the hysteresis and susceptibility loss. Specifically, the 28 nm Fe3O4 nanoparticles exhibit an enhanced SAR value of 801 W g-1 which is nearly an order higher than that of the commercially available nanoparticles.

Inductive Thermal Effect of Ferrite Magnetic Nanoparticles

“…Later, Xu et al found that by changing the heating conditions, and ratios of oleylamine and oleic acid, the size of Fe 3 O 4 NPs can be tuned from 14 to 100 nm [67]. Recently, oleylamine was used as a multitasking agent, acting as a solvent, and reducing and surface functionalizing agents, to prepare monodispersed Fe 3 O 4 NPs with a reasonably large magnetization value [68,69,70,71]. The experiment confirms that the presence of excess amount of oleylamine offers an adequately strong reductive environment for the Fe-precursor and leads to the formation of Fe 3 O 4 NPs at a reasonably low temperature of 240 °C.…”

“…The experiment confirms that the presence of excess amount of oleylamine offers an adequately strong reductive environment for the Fe-precursor and leads to the formation of Fe 3 O 4 NPs at a reasonably low temperature of 240 °C. Figure 6A shows the representative TEM micrographs of monodispersed Fe 3 O 4 nanoparticles of size ranging from 6 to 24 nm, prepared by thermolysis of Iron(III) acetylacetonate in oleic acid and oleylamine [71]. These synthesis methods were also extended to formulate MFe 2 O 4 (M = Co, Ni, and Mn) NPs.…”

Nanoformulation Design Including MamC-Mediated Biomimetic Nanoparticles Allows the Simultaneous Application of Targeted Drug Delivery and Magnetic Hyperthermia

“…In order to deliver nanoparticles with these characteristics, their composition, size, and shape should be optimized. For instance, magnetite nanoparticles with sizes within the range of 4–27 nm [ 10 , 11 , 12 ] and cuboctahedral versus cubic have been demonstrated to show the highest specific absorption rate (SAR) values for magnetic hyperthermia [ 13 ]. On the other hand, and to be able to combine magnetic hyperthermia with targeted drug delivery, the magnetic nanoparticles should be easily functionalized with different moieties, e.g., a drug and a probe, and to this goal, they should provide a chemical surface pattern mediating the binding for these molecules.…”

Magnetic properties of hematite (α − Fe2O3) nanoparticles synthesized by sol-gel synthesis method: The influence of particle size and particle size distribution

“…Iron(III) oxides show remarkable magnetic properties, both for fundamental investigations and practical applications. The magnetic properties of these materials have been shown to depend on their size, shape, and microstructure [11][12][13][14][15][16]. In particular, iron(III) oxides are an attractive group of materials with a wide range of magnetic properties, from antiferromagnetic, superparamagnetic and weak ferromagnetic to ferrimagnetic [17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”