Comprehensive studying the role of coating on structure, magnetic properties, and heating efficiency for chitosan-coated Co0.2Zn0.8Fe2O4 nanoparticles

Abstract

In this work, chitosan-coated Co_0.2Zn_0.8Fe₂O₄ and Co_0.2Zn_0.8Fe₂O₄ nanoparticles (NPs) are successfully synthesized by the co-precipitation method. According to data on lattice parameter (a), density (ρ_XRD), and size (D_HW), the chitosan-coated Co_0.2Zn_0.8Fe₂O₄ (a = 8.396 Å, ρ_XRD = 5.39 g/cm³, D_HW = 11.2 nm) have structural parameters almost like those of Co_0.2Zn_0.8Fe₂O₄ NPs (a = 8.401 Å, ρ_XRD = 5.38 g/cm³, D_HW = 10.7 nm). Besides, the high-resolution Transmission Electron Microscopy images claimed that the Co_0.2Zn_0.8Fe₂O₄ NPs have a medium size of 11.1 nm with a narrow distribution. The successful coating is demonstrated by the Fourier transform infrared spectra of two samples. Although there is a decrease in saturation magnetization from 36.3 emu/g (Co_0.2Zn_0.8Fe₂O₄) to 33.4 emu/g (chitosan-coated Co_0.2Zn_0.8Fe₂O₄), this coated sample (68.8 kJ/m3) have larger magnetic anisotropy than that of Co_0.2Zn_0.8Fe₂O₄ NPs (61.4 kJ/m3). The chitosan coating improves the dispersion of the chitosan-coated Co_0.2Zn_0.8Fe₂O₄ NPs in an aqueous and helps them into non-toxicity against the liver (HepG2) and breast (MCF7) cancer cell lines. Interestingly, it also enhances their hydrodynamic size (161.2 nm), which leads to the domination of Neel relaxation losses in the chitosan-coated Co_0.2Zn_0.8Fe₂O₄ NPs’ heating generation mechanism. As a result, this coated sample have a high specific absorption rate (291.1 W/g) at 300 Oe (∼2.4 kA/m) and 340 kHz. In particular, this also has a high effective specific absorption rate (1.5–2.6 nHm²/kg) at 150–300 Oe and 340 kHz. All these reveal the CZFO@CS NPs’ high applicability in hyperthermia.