The cell uptake properties and hyperthermia performance of Zn _0.5 Fe _2.5 O ₄ /SiO ₂ nanoparticles as magnetic hyperthermia agents

Abstract

Zn 0.5 Fe 2.5 O 4 nanoparticles (NPs) of 22 nm are synthesized by a one-pot approach and coated with silica for magnetic hyperthermia agents. The NPs exhibit superparamagnetic characteristics, high-specific absorption rate (SAR) (1083 wg −1 , f = 430 kHz, H = 27 kAm −1 ), large saturation magnetization ( M s = 85 emu g −1 ), excellent colloidal stability and low cytotoxicity. The cell uptake properties have been investigated by Prussian blue staining, transmission electron microscopy and the inductively coupled plasma-mass spectrometer, which resulted in time-dependent and concentration-dependent internalization. The internalization appeared between 0.5 and 2 h, the NPs were mainly located in the lysosomes and kept in good dispersion after incubation with human osteosarcoma MG-63 cells. Then, the relationship between cell uptake and magnetic hyperthermia performance was studied. Our results show that the hyperthermia efficiency was related to the amount of internalized NPs in the tumour cells, which was dependent on the concentration and incubation time. Interestingly, the NPs could still induce tumour cells to apoptosis/necrosis when extracellular NPs were rinsed, but the cell kill efficiency was lower than that of any rinse group, which indicated that local temperature rise was the main factor that induced tumour cells to death. Our findings suggest that this high SAR and biocompatible silica-coated Zn 0.5 Fe 2. O 4 NPs could serve as new agents for magnetic hyperthermia.

The Effect of Zn-Substitution on the Morphological, Magnetic, Cytotoxic, and In Vitro Hyperthermia Properties of Polyhedral Ferrite Magnetic Nanoparticles

“…Congruent with the current results, Wang et al obtained similar cytotoxicity for synthesized ZnF MNPs coated with silica and a diameter of 22 nm [33]. The authors evaluated the toxicity in two different cell types, at concentrations ranging from 50 to 1000 µg/mL (equivalent to 12.5 to 250 µg/cm 2 ), and observed a statistical decrease of viability starting from an exposure dose of 150 µg/cm 2 [33]. For uncoated spherical ZnF particles with an average size of 40 nm, a strong decrease in the cellular viability of cancerous cells was observed.…”

“…Due to their higher surface and cytoplasmic volume, BJ cells internalized on average 2-2.5 times more ZnF01 and ZnF02 nanoparticles than their cancerous counterpart (Figure 9c,f). In a recent study, Wang et al evaluated the cellular uptake and hyperthermia performance of Zn-MNPs coated with silica and reported that the cellular internalization increases as the exposure duration increases [33]. After a 12 h incubation with an exposure dose of 200 µg/mL (equivalent to 50 µg/cm 2 ), osteosarcoma (MG-63) cells internalized a Fe 3+ quantity of 60 pg/cell [33].…”

“…In a recent study, Wang et al evaluated the cellular uptake and hyperthermia performance of Zn-MNPs coated with silica and reported that the cellular internalization increases as the exposure duration increases [33]. After a 12 h incubation with an exposure dose of 200 µg/mL (equivalent to 50 µg/cm 2 ), osteosarcoma (MG-63) cells internalized a Fe 3+ quantity of 60 pg/cell [33]. The reported value is close to the current results for cancerous cells, at an exposure dose of 62.5 µg/cm 2 and exposure for 24 h, the Fe 3+ content per A549 cell being approximately 60 pg/cell and 65 pg/cell for ZnF01 and ZnF02 particles, respectively.…”

“…In a recent study, Wang et al reported the MH treatment (H = 10-14 kA/m, f = 430 kHz) of human osteosarcoma (MG-63) cells exposed to 400 µg/mL (100 µg/cm 2 ) of silanized Zn-MNPs [33]. When the cells were exposed to the entire dose of nanoparticles, temperatures reaching 43-46 • C induced marked cellular death and, depending on the incubation time, the percentage of viable cells varied from 22% to 50%.…”

“…Several synthesis routes have been employed for the preparation of ZnF particles, exhibiting different particle size histograms, cation distribution between the two sublattices, and magnetic properties. The preparation of single-crystalline monodisperse ZnF-particles with magnetic properties closed to bulk-like ones has been achieved by thermal decomposition of metal acetylacetonates and oleates in organic solvents at high temperatures [25,26,28,29,[31][32][33][34]. In most cases, this method enables the formation of secondary phases as wüstite [35].…”