Magnetic hyperthermia efficiency and MRI contrast sensitivity of colloidal soft/hard ferrite nanoclusters

Abstract

The use of magnetic nanostructures as theranostic agents is a multiplex task as physiochemical and biochemical properties including excellent magneto-responsive properties, low toxicity, colloidal stability and facile surface engineering capability are all required. Nonetheless, much progress has been made in recent years synthesis of "all-in-one" MNPs remain unambiguously challenging. Towards this direction, in this study is presented a facile incorporation of a soft magnetic phase (MnFeO NPs) with a hard phase (CoFeO NPs) in the presence of the biocompatible polymer sodium dodecyl sulfate (SDS), into spherical and compact bi-magnetic nanoclusters (NCs) with modulated magnetic properties that critically enhance hyperthermic efficiency and MRI contrast effect. Hydrophobic MnFeO and CoFeO NPs coated with oleylamine of the same size (9 nm) were used as primary building units for the formation of the bi-magnetic NCs through a microemulsion approach where a set of experiments were conducted to identify the optimal concentration of SDS (19.5 mM) for the cluster formation. Additionally, homo-magnetic NCs of MnFeO NPs and CoFeO NPs, respectively were synthesized for comparative studies. The presence of distinct magnetic phases within the bi-magnetic NCs resulting in synergistic behavior, where the soft phase offers moderate coercivity H and the hard one high magnetization M. Increased specific loss power (SLP) value was obtained for the bi-magnetic system (525 W/g) when compared with the homo-magnetic NCs (104 W/g for MnNCs and 223 W/g for CoNCs) under field conditions of 25 kA/m and 765 kHz. Relaxivities (r) of the bi-magnetic NCs were also higher (81.8 mM s) than those of the homo-magnetic NCs (47.4 mM s for MnNCs and 3.1 mM s for CoNCs), while the high r/r value renders the system suitable for T-weighted MRI imaging.

Aminodextran Coated CoFe2O4 Nanoparticles for Combined Magnetic Resonance Imaging and Hyperthermia

“…Figures 5 and 6 indicate that both samples generate higher negative signal intensity to assist in visualizing cells that appear bright. This observation supports their better contrast capability as sensitive MRI contrast agents (CAs) [40]. MNPs in colloids are capable to undergo higher local inhomogeneity as compared to that of the Gd magnetic field, externally applied.…”

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

“…Generally, dipolar interaction energy imposes a disordering torque which interrupts the Néel relaxation of the magnetic moment through the energy barrier 68 . Interestingly, despite the higher values of saturation magnetization and anisotropy for F, the NPs heating response is more positive or higher SAR is obtained for CS nanocomposites FN and NF, which is due to the magnetic EB or exchange coupling at the interface of the two materials 12 , 26 , 29 . It indicated that the interface exchange anisotropy of the CS arrangements tuned the effective anisotropy, which in turn enhanced the heating efficiency of the MNPs 6 .…”

Effect of apple cider vinegar agent on the microstructure, phase evolution, and magnetic properties of CoFe2O4 magnetic nanoparticles

“…CoFe 2 O 4 (CFO) with a cubic inverse spinel structure contains Co 2+ ions distributed at octahedral sites (B) and Fe 3+ ions placed at tetrahedral sites (A) and octahedral sites (B) . Cobalt ferrite has the excellent properties including antibacterial characteristics, low toxicity, low cost, mechanical hardness, large crystalline anisotropy, high coercivity, high Curie temperature, moderate saturation magnetization, and considerable chemical and thermal stability that make it as one of the most practical candidates for biomedical applications. The widespread range of its applications in various industries such as data storage devices, sensitive sensors, high density magnetic recorders, targeted drug delivery systems, electronic devices, magnetic resonance imaging, catalysis, and ferrofluids indicates the importance of this material category.…”

“…Moreover, the numerous studies have been done to modify morphology, size, and magnetic properties of CFO by doping the alloying elements such as V, Ni, Mn, Ti–Al, Ce, Zn, Gd, In, and rare earth elements . On the other hand, the most common methods which are used for the synthesis of CoFe 2 O 4 nanoparticles are co‐precipitation, solvothermal, hydrothermal, micro‐emulsion, and sol‐gel methods . Among these methods, sol‐gel auto‐combustion is known as an efficient technique to produce high purity and homogeneity crystalline particles with relatively low reaction temperature, low reaction time, and simple manipulations .…”