Synthesis and Characterization of Bi-Magnetic Core/Shell Nanoparticles for Hyperthermia Applications

Abstract

Magnetic nanoparticles, which exhibit a high specific absorption rate (SAR), have drawn a great deal of interest for hyperthermia. Bi-magnetic CS-MNPs of Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> @MnFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> with x ranging between 0 and 0.8 have been synthesized by seed-mediated growth. Structural morphology and magnetic properties have been studied. This paper presents the effects of substitution of Zn <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> on the structural and magnetic properties of Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> @MnFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> nanoparticles. The structure and morphology of the CS-MNPs was established by using X-ray diffraction (XRD), transmission electron microscopy (TEM), and dark field TEM (DF-TEM). XRD patterns confirm the existence of a single-phase cubic spinel crystal structure. The average particle size has been estimated from the statistical analysis of the TEM images. DF-TEM results confirmed the formation of CS-MNPs. Vibrating sample magnetometery demonstrated an increase in saturation magnetization with an increasing Zn concentration up to x = 0.4 and a decrease thereafter. High heating efficacy of CS-MNPs may extend hyperthermia therapy to deeper tumors. The experimental results showed that CS-MNPs have a higher SAR than the core ones. These nanoparticles are coupled-exchange between soft and hard magnetic phases.