Some medical applications of magnetic nanoparticles require direct contact with healthy tissues and blood. If nanoparticles are not designed properly, they can cause several problems, such as cytotoxicity or hemolysis. A strategy for improvement the biological proprieties of magnetic nanoparticles is their functionalization with biocompatible polymers and nonionic surfactants. In this study we compared bare magnetite nanoparticles against magnetite nanoparticles coated with a combination of polyethylene glycol 3350 (PEG 3350) and polysorbate 80 (Tween 80). Physical characteristics of nanoparticles were evaluated. A primary culture of sheep adipose mesenchymal stem cells was developed to measure nanoparticle cytotoxicity. A sample of erythrocytes from a healthy donor was used for the hemolysis assay. Results showed the successful obtention of magnetite nanoparticles coated with PEG 3350-Tween 80, with a spherical shape, average size of 119.2 nm and a zeta potential of +5.61 mV. Interaction with mesenchymal stem cells showed a non-cytotoxic propriety at doses lower than 1000 µg/mL. Interaction with erythrocytes showed a non-hemolytic propriety at doses lower than 100 µg/mL. In vitro information obtained from this work concludes that the use of magnetite nanoparticles coated with PEG 3350-Tween 80 is safe for a biological system at low doses.

Due to their potential in numerous interdisciplinary fields, such as drug delivery, hyperthermia, and magnetic resonance imaging, magnetic nanoparticles have attracted widespread attention. In this study, cobalt ferrite nanoparticles are synthesized with varying amounts of iron and cobalt ions, and their cytocompatibility is evaluated before and after surface modification with amino‐silane (AEPTMS). Characterization of the synthesized nanoparticles is performed using scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy. In addition, it is observed that a slight reduction in the saturation magnetization of the coated materials. The cytotoxicity of these materials is evaluated using the MTT assay on fibroblast cells. This study focuses on the importance of the interface between the surface of magnetic nanoparticles, their coating, and their interaction with cells. This study presents an innovative approach to enhancing the cytocompatibility of cobalt ferrite nanoparticles through chemical substitution and surface modification with AEPTMS. The key findings demonstrate that the iron and cobalt ion ratio significantly impacts cytotoxicity, with the AEPTMS coating found to increase cell viability. These findings demonstrate the potential of these materials for biomedical applications, highlighting the importance of both the composition and surface coating of magnetic nanoparticles for biomedical applications.

Considerable effort has been focused on improving the control of size, shape, and surface modifications to detect proteins. The purpose of this study was to compare the efficiencies of aminosilane-coated magnetite (As-M) nanoparticles (NPs), dextran-coated magnetite nanoparticles (Dx-M), and bare nanoparticles for conjugating single-chain variable fragment antibodies (scFvs) with the aim of detecting the human epidermal growth factor receptor 2 (HER2) protein. Dx-M and As-M NPs were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and Raman spectroscopy. Dx-M and As-M were conjugated with a monoclonal scFv for active targeting of the HER2 antigen. Aminosilane surface coating enhanced the scFv conjugation efficiency over twofold compared to that of the dextran-coated magnetite NPs for the detection of HER2 proteins.

La-0.7 Sr-0.3 MnO3 (LSMO) nanoparticles have been obtained via solution combustion synthesis (SCS) using urea and glycine as fuels. Also, La-0.7 Sr-0.27 Ca-0.03 MnO3 (LSCMO) nanoparticles have been synthesized through solution combustion using urea as fuel. In this paper, the combustion process was carried out with a fuel to oxidant ratio giving fuel deficient conditions ( $\phi < {1}$ ). The thermal analysis (TGA) indicate that the organic residues from the urea-nitrates gel mixture are eliminated above 600 degrees C and the post-synthesis heat treatment yields the formation of the desired phase without impurities. The obtained phases were analyzed using X-ray diffraction. The infrared analysis confirms the purity of the samples obtained using urea. However, the sample obtained using glycine confirms the formation of SrCO3. The morphology was analyzed using a FE-SEM microscope, and it was found that the particles present a spherical shape with a mean size of around 45 nm in the selected samples. The samples' energy dispersive X-ray spectra show that the desired elements (La, Sr, Ca, Mn and O) are present in the nanoparticles. The measured zero field cooled (ZFC) and field cooled (FC) magnetizations were recorded from 4.5 to 380 K at 105 A/m to obtain their blocking and Curie temperatures. Moreover, the hysteresis loops measured at room temperature confirm the superparamagnetic behavior of the elaborated samples. According to the results obtained, these nanoparticles have interesting properties that make them candidates to explore not only for their potential in biomedical applications but also in refrigeration and magnetic storage devices.

Magnetic nanoparticles are proposed as heat mediators in hyperthermia treatments. In this work, three core-shell materials of different composition and magnetic anisotropy were developed to determine their properties as crystal size, saturation magnetization and their coating with organic molecules. The magnetic core of these materials was made by means of the coprecipitation reaction, following the stoichiometric ratio X+2Fe2+3O4 where X is Fe, Co or Ni for each material. From the X-ray diffraction patterns the crystal size of each material was determined, these were 10.39 nm, 7.27 nm y 3.86 nm. In addition, magnetization was 55.84 emu/g, 36.56 emu/g y 16.21 emu/g for magnetite, cobalt ferrite and nickel respectively. Each material was coated with aminosilane and by FTIR the vibrational modes of the C-N, N-H, C-H and Si-O bonds involved in the coating were identified.