Heating Efficiency of Triple Vortex State Cylindrical Magnetic Nanoparticles

Abstract

A well-established method for treating cancerous tumors is magnetic hyperthermia, which uses localized heat generated by the relaxation mechanism of magnetic nanoparticles (MNPs) in a high-frequency alternating magnetic field. In this work, we investigate the heating efficiency of cylindrical NiFe MNPs, fabricated by template-assisted pulsed electrodeposition combined with differential chemical etching. The cylindrical geometry of the MNP enables the formation of the triple vortex state, which increases the heat generation efficiency by four times. Using time-dependent calorimetric measurements, the specific absorption rate (SAR) of the MNPs was determined and compared with the numerical calculations from micromagnetic simulations and vibrating sample magnetometer measurements. The magnetization reversal of high aspect ratios MNPs showed higher remanent magnetization and low-field susceptibility leading to higher hysteresis losses, which was reflected in higher experimental and theoretical SAR values. The SAR dependence on magnetic field strength exhibited small SAR values at low magnetic fields and saturates at high magnetic fields, which is correlated to the coercive field of the MNPs and a characteristic feature of ferromagnetic MNPs. The optimization of cylindrical NiFe MNPs will play a pivotal role in producing high heating performance and biocompatible magnetic hyperthermia agents.

A critical review of bioceramics for magnetic hyperthermia

“…For example, see Refs [39][40][41][42]. Pyrolysis of polycarbosilane polymer has been modeled by Key et al 43 Ideally, the available individual models for polymer infiltration and pyrolysis should be combined to construct a model for the PIP process. However, some of the above-referenced models have been developed at such a level of detail that they cannot be used to analyze large components while keeping the numerical solution procedure manageable.…”

“…Different synthesis methods lead to various shapes and morphologies like cubic, parallelepiped, cylindrical, or triangular prism. [41][42][43][44] Lu et al demonstrated that the magnetic coercivity of MNPs increases with increasing value of aspect ratio, that is, when the nanoparticle shape changes from spherical to elliptical. The H c reduction is mainly due to the distortion and anisotropy and small deviations from uniformity, which can induce additional anisotropy.…”

“…For exam 42 ]. Pyrolysis of polycarbosilane polyme by Key et al43 Summary of selected studies on magnetic bioactive ceramics for cancer therapy application…”

Hollow spherical Mn0.5Zn0.5Fe2O4 nanoparticles with a magnetic vortex configuration for enhanced magnetic hyperthermia efficacy

“…The vortex nanoring, [19][20][21][22] nanodisc, 23 cubic 24 and ellipsoid 25 structures with high saturation magnetization have been reported to show high MHT efficiency. Furthermore, Wong et al 26,27 demonstrated a substantial fourfold increase in heating efficiency, which was attributed to the formation of multiple vortices as opposed to a single vortex configuration. The utiliz-ation of magnetic nanoparticles featuring a multi-vortex structure presents a promising way towards achieving even greater advancements in the heating efficiency.…”

From Micromagnetic to In Silico Modeling of Magnetic Nanodisks for Hyperthermia Applications

“…[22] Another potential application is magnetic hyperthermia for cancer cure, where disk-, ring-, cylinder-, sphere-, cube-, or flower-shaped nanostructures made of different magnetic materials have been explored as heating agents for the generation of strongly localized increments of temperature. [23][24][25][26][27][28][29][30][31][32] Under the action of ac magnetic fields (f ≅ 50-500 kHz) and for sufficiently large size, they can produce heat via magnetic hysteresis, showing values of specific loss power (SLP) higher than those of the clinically approved SPIONs. [33][34][35][36][37] Moreover, they can be characterized by vortex state at remanence (e.g., for discoidal or annular shape), feature that leads to small magnetostatic interactions and, advantageously, to low probability of aggregation.…”