Maghemite (γ-Fe2O3) and γ-Fe2O3-TiO2 Nanoparticles for Magnetic Hyperthermia Applications: Synthesis, Characterization and Heating Efficiency.

O M Lemine,Nawal Madkhali,Marzook Alshammari,Moktar Hjiri,Kheireddine El-Boubbou,Ali A Yousif,Lassad El Mir,Abbasher Gismelseed,Saja Algessair

doi:10.3390/ma14195691

Abstract

In this report, the heating efficiencies of γ-Fe2O3 and hybrid γ-Fe2O3-TiO2 nanoparticles NPs under an alternating magnetic field (AMF) have been investigated to evaluate their feasible use in magnetic hyperthermia. The NPs were synthesized by a modified sol-gel method and characterized by different techniques. X-ray diffraction (XRD), Mössbauer spectroscopy and electron microscopy analyses confirmed the maghemite (γ-Fe2O3) phase, crystallinity, good uniformity and 10 nm core sizes of the as-synthesized composites. SQUID hysteresis loops showed a non-negligible coercive field and remanence suggesting the ferromagnetic behavior of the particles. Heating efficiency measurements showed that both samples display high heating potentials and reached magnetic hyperthermia (42 °C) in relatively short times with shorter time (~3 min) observed for γ-Fe2O3 compared to γ-Fe2O3-TiO2. The specific absorption rate (SAR) values calculated for γ-Fe2O3 (up to 90 W/g) are higher than that for γ-Fe2O3-TiO2 (~40 W/g), confirming better heating efficiency for γ-Fe2O3 NPs. The intrinsic loss power (ILP) values of 1.57 nHm2/kg and 0.64 nHm2/kg obtained for both nanocomposites are in the range reported for commercial ferrofluids (0.2–3.1 nHm2/kg). Finally, the heating mechanism responsible for NP heat dissipation is explained concluding that both Neel and Brownian relaxations are contributing to heat production. Overall, the obtained high heating efficiencies suggest that the fabricated nanocomposites hold a great potential to be utilized in a wide spectrum of applications, particularly in magnetic photothermal hyperthermia treatments.

Highlights

The unique properties of magnetic iron oxide nanoparticles (NPs) confirmed its use in several applications such as photocatalysis, photonic, magnetic storage and electronic devices to biomedicine and theranostics [1,2]
X-ray diffraction (XRD) patterns of γ-Fe2O3-TiO2 nanocomposite (Figure 1b) are similar to patterns obtained for γ-Fe2O3 but new peaks appear at 2θ = 25.3◦, 37.86◦, 48.2◦, 54.1◦, 55.2◦ are attributed to anatase-TiO2 [29], while the peaks located at 2θ = 27.57◦, 41.02◦, 54.3◦, 68.96◦ are due to the rutile TiO2 [30]
The intrinsic loss power (ILP) values for both samples are in the range reported for commercial ferrofluids (0.2–3.1 nHm2/kg) [42]

Summary

Introduction

The unique properties of magnetic iron oxide nanoparticles (NPs) confirmed its use in several applications such as photocatalysis, photonic, magnetic storage and electronic devices to biomedicine and theranostics [1,2]. Among these applications in clinical practice is their utilization in magnetic fluid hyperthermia (MFH) [3]. Bifunctional iron oxide-based NPs, with both photo and magnetic properties, are expected to exhibit high potentials, in multimodal photothermal therapies [7,8,9]. There is, a pressing need to understand the heat generated from such hybrid constructs and to show the influence of the added metal on the overall magnetism and heating properties of iron oxides

Methods

Results

Conclusion