Israel Alejandro Flores Urquizo

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.

Magnetic nanoparticle interfaces have aroused great scientific research interest in the biomedical area since the interaction of cells or biomolecules with nanoparticles is determined by the surface properties. Currently, in medical applications, there is a need to study cell interaction and growth, along with changes in structural or magnetic properties, attributed to nanoparticle coatings. In this study the coercive field changes in Ni_xFe_3‐xO₄ nanoparticles (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) driven by partial or total substitution of Fe²⁺ content by Ni²⁺, and by aminosilane coating are evaluated. The nanoparticles are synthesized by the coprecipitation method. The inverse spinel structure is confirmed by X‐ray diffraction results and Raman spectra. The aminosilane coating is confirmed by energy‐dispersive X‐ray spectroscopy and Fourier transform infrared spectroscopy. Dynamic light scattering confirms a mean hydrodynamic size of 10 nm. Scanning electron microscopy micrographs of the uncoated and aminosilane‐coated samples show that the particles have a hemispherical shape. The coating increases the coercive field. In addition, uncoated Ni_0.2Fe_2.8O₄ has the highest viability in both MCF7 and HeLa cell lines, and aminosilane coating decreases cell viability. This study contributes to future applications of nanomedicine, such as hyperthermia and drug delivery.

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.

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.

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.