Improved specific loss power on cancer cells by hyperthermia and MRI contrast of hydrophilic Fe_xCo_1‐xFe₂O₄ nanoensembles

Abstract

Ferrite-based ferri/superparamagnetic nanoparticles can be rapidly heated by an external alternating magnetic field (AMF) to induce tissue necrosis of the adjacent microenvironment, but in addition provide magnetic resonance imaging (MRI) contrast utilizing enhanced water relaxivity. Here we characterized nanoensembles of Fe-Co mixed spinel ferrites (i.e. Fe Co Fe O , where x ranges from 0.2 to 0.8) synthesized by chemical co-precipitation. With nanoensembles of increasing Co content the saturation magnetization improved, while lattice parameter remained relatively constant. MRI water (transverse) relaxivity at 11.7 T was also boosted with increasing Co content. Efficiency of AMF-induced heating was quite comparable for the nanoensembles with either chitosan or polyethylene glycol (PEG) coating except for PEG-coated Fe Co Fe O , which was twice as less efficient as others. While toxicity of the nanoensembles with either coating examined on 9L tumor cell cultures showed no significant differences, upon AMF exposure (i.e. heat-induced necrosis) Fe Co Fe O composition with different values of x showed quite dramatic effects on cell death of tumor cells with both coatings. This study lays the ground work for further characterization of other mixed spinel ferrites, and in addition we expect that chitosan and PEG coated Fe Co Fe O of all the compositions will have good potential for preclinical applications in vivo. Copyright © 2016 John Wiley & Sons, Ltd.

Synthesis of Magnetic Ferrite Nanoparticles with High Hyperthermia Performance via a Controlled Co-Precipitation Method

“…Cobalt ferrite nanoparticles have been prepared by several methods, including sol-gel [11], hydrothermal [12,13], co-precipitation [14], and thermal decomposition methods [15,16]. Using the co-precipitation process, many researchers have made efforts to achieve the smallest possible particles and to improve the magnetic properties and SLP of the cobalt ferrite nanoparticles and cobalt zinc ferrite nanoparticles [14,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35]. The ferromagnetic-superparamagnetic size threshold for cobalt ferrite nanoparticles has been reported by Pereira et al, who prepared superparamagnetic cobalt ferrite nanoparticles with the tuning of particle size (4.2−4.8 nm) and magnetic properties ( M s 30.6–48.8 emu/g) using a co-precipitation method.…”

Mapping Extracellular pH of Gliomas in Presence of Superparamagnetic Nanoparticles: Towards Imaging the Distribution of Drug-Containing Nanoparticles and Their Curative Effect on the Tumor Microenvironment

“…Owing to their strong superparamagnetic properties, tunable size, shape, coating, and magnetic susceptibility, SPIO-NPs have gained utility as therapeutic agents in alternating magnetic field hyperthermia [ 81 – 85 ], as MRI contrast agents for cell tracking [ 86 – 89 ], and for imaging tumor location/size as well as drug delivery [ 40 , 74 , 90 ]. Drug delivery imaging with SPIO-NPs is often accomplished by coencapsulating drugs and SPIO into a given nanocarrier platform (e.g., micelles or liposomes).…”

Brain Tumor Diagnostics and Therapeutics with Superparamagnetic Ferrite Nanoparticles

“…These suggest that larger nanoparticle size with lower anisotropy may be more favorable for hyperthermia, but at the same time access of larger nanoparticles can provide delivery challenges. Given that Tackett and coworkers [ 60 ] showed a significant magnetocrystalline anisotropy difference between Fe 3 O 4 and CoFe 2 O 4 nanoparticles (i.e., 14 and 380 kJ/m 3 ), Hoque and coworkers [ 10 ] hypothesized that the Fe-Co mixed spinel system will allow for effective tuning of the anisotropy.…”

“…Hoque and coworkers [ 10 ] synthesized Fe-Co mixed spinel ferrites by chemical coprecipitation (i.e., Fe x Co 1− x Fe 2 O 4 , where x = 0.8, 0.6, 0.4, 0.2) using NH 4 OH or NaOH, which required molar ratio of [M 2+ ]/[Fe 3+ ] at 1 : 2 where M 2+ is the salt of divalent Fe and Co dissolved in distilled water. To avoid Fe 2+ oxidation, all reactions were carried out in N 2 at normal room temperature.…”

“…The right panel shows the concentration dependence of the nanoparticles in solution for mortality of 9L cells exposed to AMF-induced heating for 30 minutes with chitosan (gray) and PEG (blue) coating. From [ 10 ] with permission. See Table 1 for other details [ 10 ].…”