Cobalt ferrite nanoparticle (CFN) has received attention in magnetic resonance imaging (MRI) as a promising contrast agent due to its higher saturation magnetization and magneto-crystalline anisotropy. However, the in vitro cytotoxicity of CFN has raised concern for its biomedical application as a diagnostic agent. The coating of CFN by a biocompatible polymer such as chitosan (CH) might lessen the biocompatibility concern. Therefore, in this study, we examined the applicability of chitosan-coated cobalt ferrite nanoparticle (CCN) as an MRI contrast dye and investigated its biocompatibility in vivo. Phantom MRI images revealed that the relaxivity of CCN was 121 (±8) mM–1s–1, indicating the potential of CCN as a T 2-weighted contrast agent. A single intravenous (iv) administration of CCN (10 mg/kg) improved the contrast of magnetic-resonance-imaging-based angiography (MRA) and brain-MRI in male albino Wistar rats compared to the control. Furthermore, toxicity studies dependent on dose (1–20 mg/kg) and time (1–28 days) in male albino Wistar rats confirmed the in vivo biocompatibility of CCN. The physical, hematological, biochemical, and histopathological observation assured that a single iv injection of CCN up to 20 mg/kg was well adjusted with liver, kidney, heart, and brain functions. The findings of the current study consolidate CCN as a promising candidate for MRI contrast dye.

Yttrium-(Y) substituted Mg-Zn ferrites with the compositions of Mg 0.5 Zn 0. 5Y x Fe 2-x O 4 (0 ≤ x ≤ 0.05) have been synthesized by conventional standard ceramic technique. The effect of Y 3+ substitution on the structural, electrical, dielectric and magnetic properties of Mg-Zn ferrites has been studied. The single phase of spinel structure with a very tiny secondary phase of YFeO 3 for higher Y contents has been detected. The theoretically estimated lattice constant has been compared with measured experimental lattice constant. The bulk density, X-ray density and porosity have been calculated. The Energy Dispersive X-ray Spectroscopy (EDS) study confirms the presence of Mg, Zn, Y, Fe and O ions in the prepared samples. Frequency dependence of conductivity has been studied and an increase in resistivity (an order) has been observed. Frequency dependence of dielectric constant (ԑʹ), dielectric loss tangent (tanδ) has been studied and the lowering of ԑʹwith the increase of Y content was noted. Dielectric relaxation time was found to vary between 15 to 31 nano seconds. The saturation magnetization (M s ), coercive field (H c ), remanent magnetization (M r ) and Bohr magneton (µ B ) have been calculated. The variation of M s has been successfully explained with the variation of A-B interaction strength due to Y substitution. The soft ferromagnetic nature also confirmed from the values of H c . The complex permeability has been studied and the initial permeability was found to increase with Y up to x = 0.01, thereafter it decreases. The values of electrical resistivity and dielectric constant with proper magnetic properties suggest the suitability of Y-substituted Mg-Zn ferrites in microwave device applications.

No abstract

No abstract