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Macrophages are known to depict two major phenotypes: classically activated macrophages (M1), associated with high production of pro-inflammatory cytokines, and alternatively activated macrophages (M2), which present an anti-inflammatory function. A precise control over M1-M2 polarization is a promising strategy in therapeutics to modulate both tissue regeneration and tumor progression processes. However, this is not a simple task as macrophages behave differently depending on the microenvironment. In agreement with this, non-consistent data have been reported regarding macrophages response to magnetic iron oxide nanoparticles (MNPs). To investigate the impact of both tissue microenvironment and MNPs properties on the obtained macrophage responses, single-core (SC) and multi core (MC) citrate coated MNPs, are synthesized and, afterwards, loaded with a macrophage polarization trigger, IL-4. The developed MNPs are then tested in macrophages subjected to different stimuli. We demonstrate that macrophages treated with low concentrations of MNPs behave differently depending on the polarization stage independently of the concentration of iron. Moreover, we find out that MNPs size and morphology determines the effect of the IL-4 loaded MNPs on M1 macrophages, since IL-4 loaded SC MNPs favor the polarization of M1 macrophages towards M2 phenotype, while IL-4 loaded MC MNPs further stimulate the secretion of pro-inflammatory cytokines

Molybdenum-99 (99Mo) is used to produce technetium-99 m (99mTc), one of the most used medical radioisotopes in the world. 99Mo is currently created by fission of uranium-235 (235U) in a small number of research nuclear fission reactors. Several problems related to the use of 235U as primary source is causing a global 99Mo generation crisis. Therefore, we are facing the need of finding new viable and safe production alternatives. Neutron activation of molybdenum is a promising candidate in which the ideal target for 99Mo production are small monodisperse molybdenum nanoparticles (Mo NPs). However, the reported procedures for the obtention of Mo NPs present either the lack of simplicity of the employed synthetic methods or the inappropriate size and monodispersity of the synthesized Mo NPs. Here, we report a simple synthetic procedure for the obtention of small-sized monodisperse metallic Mo NPs. In the studied conditions, thermal decomposition of Mo(CO)6 produced oleylamine coated Mo NPs. The oleylamine layer was included with the purpose of avoiding oxidation. Although an oxide patina was still formed on the surface of the Mo NPs, the core remains in a metallic phase after several weeks from its production, as it was confirmed by X-ray photoelectron spectroscopy analysis (XPS). The described synthetic procedure provides a simple method for the obtention of Mo NPs with optimum characteristics as non-fission method for 99Mo production

Recientemente, la nanomedicina ha surgido de la interfaz entre la nanotecnología y la biotecnología, dando lugar a la aparición de importantes avances en el sector biomédico. Esta nueva vertiente de la biomedicina, requiere el desarrollo de materiales que incorporen nanoestructuras multifuncionales que integren en una única estructura materiales con propiedades específicas con actividad teragnóstica, como son las nanopartículas magnéticas, para diversas aplicaciones biomédicas in vitro o in vivo. En el presente trabajo, se ha llevado a cabo la síntesis de nanoestructuras magnéticas por diferentes rutas sintéticas optimizadas y su posterior evaluación en aplicaciones biomédicas de actual interés tales como la detección de biomarcadores de enfermedades neurodegenerativas, terapias celulares o el diagnóstico por imagen multimodal.

In this work, ZnO nanoparticles (NPs) were successfully synthesized and coated with oleic acid (OA). The mean diameter of these NPs (ZnO-OA) was around 11.5 nm, their core was characterized by XRD and their coating by FTIR and Raman. Homogeneous dispersions at different concentrations (0.10, 0.25, 0.50, 0.75 and 1.00 wt%) of ZnO-OA in polyalphaolefin 40 (PAO40) oil were thermophysically and tribologically characterized. Both density and viscosity values increased with the concentration of NPs, reaching relative increments of 0.5% and 4.0%, respectively, for the 1 wt% nanodispersion. Tribological tests were performed at 353.15 K using an Anton Paar MCR 302 rheometer equipped with a tribological ball-on three-pins configuration testing module. Regarding the tribological behavior, the optimal concentration was 0.25 wt% of ZnO-OA (25% of reduction in the friction coefficient and 82% wear reduction in terms of cross sectional area, respect to those obtained with the neat base oil). The rolling mechanism owing to the spherical shape of the nanoadditives, transforming sliding friction into rolling friction, and the mending effect could explain the better tribological performance of nanolubricants with respect to that of neat PAO40. In addition, the presence of PAO40, ZnO-OA NPs and iron oxides was evidenced from confocal Raman microscopy on the worn surfaces obtained from tribological test with PAO40 + 0.25 wt% ZnO-OA dispersion

The main task of this work is to study the tribological performance of nanolubricants formed by trimethylolpropane trioleate (TMPTO) base oil with magnetic nanoparticles coated with oleic acid: Fe3O4 of two sizes 6.3 nm and 10 nm, and Nd alloy compound of 19 nm. Coated nanoparticles (NPs) were synthesized via chemical co-precipitation or thermal decomposition by adsorption with oleic acid in the same step. Three nanodispersions of TMPTO of 0.015 wt% of each NP were prepared, which were stable for at least 11 months. Two different types of tribological tests were carried out: pure sliding conditions and rolling conditions (5% slide to roll ratio). With the aim of analyzing the wear by means of the wear scar diameter (WSD), the wear track depth and the volume of the wear track produced after the first type of the tribological tests, a 3D optical profiler was used. The best tribological performance was found for the Nd alloy compound nanodispersion, with reductions of 29% and 67% in friction and WSD, respectively, in comparison with TMPTO. On the other hand, rolling conditions tests were utilized to study friction and film thickness of nanolubricants, determining that Fe3O4 (6.3 nm) nanolubricant reduces friction in comparison to TMPTO

Early diagnosis of disease and follow-up of therapy is of vital importance for appropriate patient management since it allows rapid treatment, thereby reducing mortality and improving health and quality of life with lower expenditure for health care systems. New approaches include nanomedicine-based diagnosis combined with therapy. Nanoparticles (NPs), as contrast agents for in vivo diagnosis, have the advantage of combining several imaging agents that are visible using different modalities, thereby achieving high spatial resolution, high sensitivity, high specificity, morphological, and functional information. In this work, we present the development of aluminum hydroxide nanostructures embedded with polyacrylic acid (PAA) coated iron oxide superparamagnetic nanoparticles, Fe3O4@Al(OH)3, synthesized by a two-step co-precipitation and forced hydrolysis method, their physicochemical characterization and first biomedical studies as dual magnetic resonance imaging (MRI)/positron emission tomography (PET) contrast agents for cell imaging. The so-prepared NPs are size-controlled, with diameters below 250 nm, completely and homogeneously coated with an Al(OH)3 phase over the magnetite cores, superparamagnetic with high saturation magnetization value (Ms = 63 emu/g-Fe3O4), and porous at the surface with a chemical affinity for fluoride ion adsorption. The suitability as MRI and PET contrast agents was tested showing high transversal relaxivity (r2) (83.6 mM−1 s −1 ) and rapid uptake of 18F-labeled fluoride ions as a PET tracer. The loading stability with 18F-fluoride was tested in longitudinal experiments using water, buffer, and cell culture media. Even though the stability of the 18F-label varied, it remained stable under all conditions. A first in vivo experiment indicates the suitability of Fe3O4@Al(OH)3 nanoparticles as a dual contrast agent for sensitive short-term (PET) and high-resolution long-term imaging (MRI).

In this paper, novel magnetic silica nanocomposites were prepared by anchoring magnetite nanoparticles onto the outer surface of mesoporous SBA-15 silica; the magnetic nanoparticles were prepared by microemulsion and solvothermal methods, varying the synthesis conditions in order to control the final physicochemical, textural and magnetic properties. The morphology and mesostructure of the materials were characterized by X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), N2 adsorption–desorption, and Transmission and Scanning Electron Microscopy (TEM and SEM). Magnetic silica nanocomposites feature a two-dimensional hexagonal arrangement constituted by a homogeneous pore channel system with diameters between 13 and 18 nm and a Brunauer–Emmett–Teller (BET) surface area higher than 260 m2 g−1. The different morphologies of the samples are given by the presence of diverse magnetic nanoparticle arrangements covalently linked onto the outer surface of the mesoporous silica rods. This confers on them a superparamagnetic behaviour with a magnetic response between 50–80 emu g−1, even though the weight percent of magnetite present in the samples does not exceed 21.7%. In addition, the magnetic nanocomposites exhibit magnetic hyperthermia with moderate Specific Absorption Rate (SAR) values