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In the last few years, magnetic nanowires have gained attention due to their potential implementation as building blocks in spintronics applications and, in particular, in domain-wall- based devices. In these devices, the control of the magnetic properties is a must. Cylindrical magnetic nanowires can be synthesized rather easily by electrodeposition and the control of their magnetic properties can be achieved by modulating the composition of the nanowire along the axial direction. In this work, we report the possibility of introducing changes in the composition along the radial direction, increasing the degrees of freedom to harness the magnetization. In particular, we report the synthesis, using template-assisted deposition, of FeNi (or Co) magnetic nanowires, coated with a Au/Co (Au/FeNi) bilayer. The diameter of the nanowire as well as the thickness of both layers can be tuned at will. In addition to a detailed structural characterization, we report a preliminary study on the magnetic properties, establishing the role of each layer in the global collective behavior of the system.

Iron oxide nanoparticles (IONPs) are suitable materials for contrast enhancement in magnetic resonance imaging (MRI). Their potential clinical applications range from diagnosis to therapy and follow-up treatments. However, a deeper understanding of the interaction between IONPs, culture media and cells is necessary for expanding the application of this technology to different types of cancer therapies. To achieve new insights of these interactions, a set of IONPs were prepared with the same inorganic core and five distinct coatings, to study their aggregation and interactions in different physiological media, as well as their cell labelling efficiency. Then, a second set of IONPs, with six different core sizes and the same coating, were used to study how the core size affects cell labelling and MRI in vitro. Here, IONPs suspended in biological media experience a partial removal of the coating and adhesion of molecules. The FBS concentration alters the labelling of all types of IONPs and hydrodynamic sizes ≥ 300 nm provide the greatest labelling using the centrifugation-mediated internalization (CMI). The best contrast for MRI results requires a core size range between 12–14 nm coated with dimercaptosuccinic acid (DMSA) producing R2* values of 393.7 s−1 and 428.3 s−1, respectively. These findings will help to bring IONPs as negative contrast agents into clinical settings.

The use of metallic nanowires is mostly reduced to scientific areas where a small quantity of nanostructures are needed. In order to broaden the applicability of these nanomaterials, it is necessary to establish novel synthesis protocols that provide a larger amount of nanowires than the conventional laboratory fabrication processes at a more competitive cost. In this work, we propose several modifications to the conventional electrochemical synthesis of nanowires in order to increase the production with considerably reduced production time and cost. To that end, we use a soft anodization procedure of recycled aluminum at room temperature to produce the alumina templates, followed by galvanostatic growth of CoFe nanowires. We studied their morphology, composition and magnetic configuration, and found that their properties are very similar to those obtained by conventional methods.