Superparamagnetic single phase zinc ferrite nanoparticles have been prepared by coprecipitation method at 200C without any subsequent calcination. The composition, crystallite size, microstructure and magnetic properties of the prepared nanoparticles were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transmission infrared spectrum (FTIR) and vibrating sample magnetometer (VSM). The XRD pattern proved that the nanoparticles were single phase cubic spinel ZnFe2O4 with crystallite size of 5nm. The magnetic measurement showed that the as-prepared nanoparticles of zinc ferrite were superparamagnet at room temperature.

In this work, an eco-friendly “green” nanocomposite of chitosan containing graphite and maghemite (g-Fe2O3) nanoparticles were prepared by solution casting method. The effect of g-Fe2O3 nanoparticles on structural, electric and dielectric properties of Chitosan-graphite (Cs-graphite) composites was investigated. The dielectric constant of Cs-graphite composites increased with incorporation of g-Fe2O3 nanoparticles. Among the composites Cs-20% graphite - 20% g-Fe2O3 has dielectric constant of ~16.5 at 1 MHz at room temperature. With increase in temperature the dielectric constant varied significantly. The conductivity of Cs-graphite is enhanced by one order of magnitude with addition of g-Fe2O3 nanoparticles, and the value is found to be 5.7x10-6 S/cm. Various parameters such as dielectric constant, dielectric loss, electric modulus, conductivity, activation energy were analyzed. Magnetic measurement of g-Fe2O3 nanoparticles and the PNCs showed superparamagnetic behaviour. A model is proposed to explain the observed dielectric behavior of polymer nanocomposites (PNCs). The formation of microcapacitors by incorporation of maghemite nanoparticles between graphite is proposed.

The present study is devoted to the development of a new magnetic resonance contrast agent based on superparamagnetic magnetite nanoparticles. The aim of the study is to create a contrast agent with improved characteristics compared to existing analogues. The process of obtaining includes two main stages such as the formation of the embryo and the growth of particles by aggregation. The size of the nanoparticles was controlled to achieve superparamagnetism. The concentration of iron in the solution was determined by X-ray fluorescence analysis. The phase composition was confirmed by X-ray phase analysis. Transmission electron microscopy and proton relaxometry were employed to evaluate the obtained solutions. The study showed that the optimal concentration of superparamagnetic nanoparticles in an aqueous solution is 0.5 mg/mL. The relaxation abilities of the synthesized particles were determined: for superparamagnetic particles (5-8 nm) - t ≈: 12.1 l/(mmol·s), t ≈: 30.1 l/(mmol·s); for ferrimagnetic particles (30-50 nm) - t ≈: 3.2 l/(mmol·s), t ≈: 35 l/(mmol·s). The cytotoxicity of the obtained nanoparticles was evaluated using an MTT test on fibroblast cells. It was found that at concentrations lower than 0.5 mg/mL, the particles do not exhibit a toxic effect on normal fibroblast cells. The research results demonstrate the feasibility of creating a new contrast agent for MR tomography based on synthesized nanoparticles of complex iron oxide. The developed contrast agent outperforms existing analogues in its characteristics and shows promising results in terms of biocompatibility.

Introduction: Iron oxide nanoparticles, owing to their very small size and superparamagnetic properties, have been considered a potential candidate for several medical applications such as magnetic cell separation, magnetic resonance imaging (MRI), magnetic targeted drug delivery magnetic hyperthermia. The present study aimed to synthesize and evaluate the characteristics of superparamagnetic iron oxide nanoparticles (SPIONs) and determine the mechanism by which they induce cell death in the presence of an extremely low-frequency magnetic field (ELMF).Methods: First, SPIONs were synthesized using the chemical co-precipitation method and then characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential. A vibrating-sample magnetometer (VSM) was used to measure the magnetic properties of the nanoparticles. Human MCF-7 breast cancer cells were treated with different concentrations of SPION in the absence and presence of a 50-Hz ELMF for 24 and 48 h. Cytotoxicity and cell viability percentage in the treated cells were measured by the MTT (3-(4, 5-dimethylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide) assay. Results: DLS and TEM analyses indicated that the SPIONs have an average size of less than 30 nm and they are superparamagnetic. VSM analyses also confirmed the superparamagnetic nature of the nanoparticles. The MTT assay indicated that high concentrations of SPIONs induced death in MCF-7 cells. In the groups treated with ELMF+SPIONs, cell death increased sharply compared with that in the groups treated with each treatment alone (P≤0.05).Conclusions: It seems that a 50-Hz ELMF in the presence of SPIONs led to cell death due to local heating.

In this study, magnetic iron oxide (maghemite) nanoparticles were prepared by single-step chemical precipitation method. Maghemite nanoparticles were synthesized by ferrous chloride (II), ferric chloride (III) and ammonium as deposition agent. Structure, particle size distribution and surface morphology of the nanoparticles were studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM). Also, the magnetic properties of the samples were measured with a vibrating sample magnetometer (VSM). XRD Spectrum clearly confirmed the formation of maghemite particles and lack of the presence of any other phase. The TEM images showed the uniform distribution of particle size. The average particle size was around 8 nm. The VSM results of maghemite nanoparticles approved the superparamagnetic of the powders. VSM results of nano particles, maghemite property represents the superparamagnetic particles.

In this paper, polymer grafted nickel-doped iron oxide nanoparticles are fabricated via an easy, one-step and fast electrochemical procedure. In the deposition experiments, iron(II) chloride hexahydrate, iron(III) nitrate nonahydrate, nickel chloride hexahydrate, and dextran were used as the bath composition. Dextran grafted nickel-doped iron oxides (DEX/NiSPIOs) were synthesized with applying direct current (dc) of 10 mA cm – 2. The magnetite crystal phase, nano-size, Ni doped content, and dextran grafting onto SPIOs were verified through X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses. Magnetic evaluation through vibrating-sample magnetometer (VSM) proved that the DEX/Ni-SPIOs product have superparamagnetic behavior with exhibiting the high saturation magnetization and negligible Ms and Hci values. Based on the obtained results, it was confirmed that the prepared dextran grafted Ni-SPIOs have suitable physico-chemical and magnetic properties for both therapeutic and diagnostic aims.

Objective: Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label mammalian cells and to monitor their fate in vivo using magnetic resonance imaging (MRI). However, the effectiveness of phenotype of labeled cells by SPIONs is still a matter of question. The aim of this study was to investigate the efficiency and biological effects of labeled mouse embryonic stem cells (mESCs) using ferumoxide- protamine sulfate complex.Materials and Methods: In an experimental study, undifferentiated mESCs, C571 line, a generous gift of Stem Cell Technology Company, were cultured on gelatin-coated flasks. The proliferation and viability of SPION-labeled cells were compared with control. ESCs and embryoid bodies (EBs) derived from differentiated hematopoietic stem cells (HSCs) were analyzed for stage-specific cell surface markers using fluorescence-activated cell sorting (FACS).Results: Our observations showed that SPIONs have no effect on the self-renewal ability of mESCs. Reverse microscopic observations and prussian blue staining revealed 100% of cells were labeled with iron particles. SPION-labeled mESCs did not significantly alter cell viability and proliferation activity. Furthermore, labeling did not alter expression of representative surface phenotypic markers such as stage-specific embryonic antigen 1 (SSEA1) and cluster of differentiation 117 (CD117) on undifferentiated ESC and CD34, CD38 on HSCs, as measured by flowcytometry.Conclusion: According to the results of the present study, SPIONs-labeling method as MRI agents in mESCs has no negative effects on growth, morphology, viability, proliferation and differentiation that can be monitored in vivo, noninvasively. Non-invasive cell tracking methods are considered as new perspectives in cell therapy for clinical use and as an easy method for evaluating the placement of stem cells after transplantation.