In Vitro Intracellular Hyperthermia of Iron Oxide Magnetic Nanoparticles, Synthesized at High Temperature by a Polyol Process

Abstract

We report the synthesis of magnetite nanoparticles (IOMNPs) using the polyol method performed at elevated temperature (300 °C) and high pressure. The ferromagnetic polyhedral IOMNPs exhibited high saturation magnetizations at room temperature (83 emu/g) and a maximum specific absorption rate (SAR) of 2400 W/gFe in water. The uniform dispersion of IOMNPs in solid matrix led to a monotonous increase of SAR maximum (3600 W/gFe) as the concentration decreased. Cytotoxicity studies on two cell lines (cancer and normal) using Alamar Blues and Neutral Red assays revealed insignificant toxicity of the IOMNPs on the cells up to a concentration of 1000 μg/mL. The cells internalized the IOMNPs inside lysosomes in a dose-dependent manner, with higher amounts of IOMNPs in cancer cells. Intracellular hyperthermia experiments revealed a significant increase in the macroscopic temperatures of the IOMNPs loaded cell suspensions, which depend on the amount of internalized IOMNPs and the alternating magnetic field amplitude. The cancer cells were found to be more sensitive to the intracellular hyperthermia compared to the normal ones. For both cell lines, cells heated at the same macroscopic temperature presented lower viability at higher amplitudes of the alternating magnetic field, indicating the occurrence of mechanical or nanoscale heating effects.

Tunable magnetothermal properties of cobalt-doped magnetite–carboxymethylcellulose ferrofluids: smart nanoplatforms for potential magnetic hyperthermia applications in cancer therapy

“…These values were chosen based on EMR and hyperthermia studies reported in the literature. 2,41,42 It was observed no difference in the EMR spectra for all the concentrations evaluated ( Fig. 7C), which evidenced the absence of interparticle interactions even with a 50-fold variation in concentration.…”

In Vitro Evaluation of Hyperthermia Magnetic Technique Indicating the Best Strategy for Internalization of Magnetic Nanoparticles Applied in Glioblastoma Tumor Cells

“…As in MHT there are two heat sources depending on nanoparticle location (surrounding tissue or cells and intracellular) [ 39 , 40 , 41 ], it is important to associate both sources to optimize MHT therapy. In this sense, the present study aims to improve the nanoparticles internalization process in C6 cells using different strategies such as static and dynamic magnetic fields, as well as transfection agent such as PLL, assisted by filtering process of SPION Amine , and it was possible to observe that SPION Amine (100 nm) were internalized in C6 cells more efficiently using magnetic field (magnetofection), associated with the transfection agent PLL.…”

Imaging Constructs: The Rise of Iron Oxide Nanoparticles

“…The basic principle of the polyol method was explained by Caruntu et al [ 36 ], as a two-step procedure; first, the formation of the hydroxides, followed by metal centres chelation. Through simple optimization of the operating synthesis conditions—namely, the nature of the magnetic precursors and precipitator, the solvents’ nature, the addition of an extra stabilizer, and the temperature, pressure and duration of the reaction—the metal nanoparticles features can be tailored for the targeted application [ 37 , 38 ]. Compared with thermal decomposition or co-precipitation methods, the polyol process yields nanoparticles with a narrow particle size distribution in a simple, environmentally friendly, reproducible and cost-effective way, without the need for an inert atmosphere [ 39 ].…”