A magnetic frequency mixing technique with a set of miniaturized planar coils was investigated for use with a completely integrated Lab-on-Chip (LoC) pathogen sensing system. The system allows the detection and quantification of superparamagnetic beads. Additionally, in terms of magnetic nanoparticle characterization ability, the system can be used for immunoassays using the beads as markers. Analytical calculations and simulations for both excitation and pick-up coils are presented; the goal was to investigate the miniaturization of simple and cost-effective planar spiral coils. Following these calculations, a Printed Circuit Board (PCB) prototype was designed, manufactured, and tested for limit of detection, linear response, and validation of theoretical concepts. Using the magnetic frequency mixing technique, a limit of detection of 15 µg/mL of 20 nm core-sized nanoparticles was achieved without any shielding.

One of the most versatile routes for the elaboration of nanomaterials in materials science, including the synthesis of magnetic iron oxide nanoclusters, is the high-temperature polyol process. However, despite its versatility, this process still lacks reproducibility and scale-up, in addition to the low yield obtained in final materials. In this work, we demonstrate a home-made multiparametric continuous flow millifluidic system that can operate at high temperatures (up to 400 °C). After optimization, we validate its potential for the production of nanomaterials using the polyol route at 220 °C by elaborating ferrite iron oxide nanoclusters called nanoflowers (CoFe₂O₄, Fe₃O₄, MnFe₂O₄) with well-controlled nanostructure and composition, which are highly demanded due to their physical properties. Moreover, we demonstrate that by using such a continuous process, the chemical yield and reproducibility of the nanoflower synthesis are strongly improved as well as the possibility to produce these nanomaterials on a large scale with quantities up to 45 g per day.

An innovative functionalization method allowing to greatly increase the Faraday effect of microstructured silica-based optical fibers is described. This method relies on the coating of a sol-gel thin film doped with magnetic field sensitive cobalt ferrite nanoparticles around the suspended core of the fiber. By varying the functionalization process parameters, both the film thickness and nanoparticle concentrations can be tailored to optimize the fiber magneto-optical response by a proper adjustment the interaction between the guided mode and the composite film. Experimental measurements in an all-fiber configuration on several samples diversely functionalized show a significant polar magneto-optical effect. A polarization rotation as large as 10 has been measured at 1550 nm when the most efficiently functionalized fiber is located inside a 0.7 cm air gap electromagnet at 1 Tesla. The present method and the developed all-fiber components are very promising candidates for the design of fiber-based sensors of magnetic fields.

Rapid detection of a biological agent is essential to anticipate a threat to the protection of biodiversity and ecosystems. Our goal is to miniaturize a magnetic pathogen detection system in order to fabricate an efficient and portable system. The detection device is based on flat, multilayer coils associated with microfluidic structures to detect magnetic nanoparticles linked to pathogen agents. One type of immunological diagnosis is based on the measurement of the magnetic sensitivity of magnetic nanoparticles (MNPs), which are markers connected to pathogens. This method of analysis involves the coupling of antibodies or antigen proteins with MNPs. Among the available magnetic techniques, the frequency mixing method has a definite advantage by making it possible to quantify MNPs. An external magnetic field composed of a low- and a high-frequency field is applied to the sample reservoir. Then, the response signal is measured and analyzed. In this paper, magnetic microcoils are implemented on a multilayer Printed Circuit Board (PCB), and a microfluidics microstructure is designed in connection with the planar coils. Simulation software, COMSOL version 5.3, provides an analytical perspective to choose the number of turns in magnetic coils and to understand the effects of changing the shape and dimensions of the microfluidics microstructure.

Yttrium iron garnet (Y₃Fe₅O₁₂, YIG) and bismuth-doped YIG (Bi_xY_3−xFe₅O₁₂, Bi-YIG) are reference materials for magneto-optical devices. Their cubic structure gives them high transparency in the near-infrared region (wide bandgap, 2.45 eV, and forbidden d–d transitions), high Faraday rotation and excellent chemical stability, making them interesting candidates for integrated optical isolators. However, synthesizing nano-sized YIG particles (less than 20 nm in size) and obtaining a magnetic liquid based on such nanoparticles prove to be major challenges, as crystallization of the garnet phase requires temperatures higher than 800 °C. Prolonged annealing triggers coalescence and grain growth, with a consequent impact on grain size. Added to this is the stoichiometric sensitivity of garnet: an excess of oxygen or of yttrium favors the formation of secondary phases (iron and yttrium perovskite YFeO₃ (YIP) or hematite α-Fe₂O₃) that are difficult to subsequently eliminate. Various synthesis strategies—such as coprecipitation, sol–gel synthesis, and self-combustion—are therefore aimed at lowering the garnet formation temperature to enable the production of small nanoparticles. However, simultaneous control of both particle size and purity remains limited. This forms the background of the work presented in this article, which combines controlled coprecipitation, high-temperature annealing and wet planetary milling in the simultaneous presence of a surfactant such as PEOS (3-[methoxy(polyethyleneoxy)propyl]trimethoxysilane). This approach enabled us to obtain YIG and Bi-YIG nanoparticles (d < 20 nm) and magnetic liquids displaying good crystallinity and durable colloidal stability. Magneto-optical measurements have confirmed the optical quality of the obtained ferrofluid, paving the way for its integration into optical isolators.

We report the case of a 74-year-old man who had undergone radical prostatectomy for prostatic cancer 6 months earlier. Elevated prostate-specific antigen during follow-up prompted ¹⁸F–prostate-specific membrane antigen (PSMA) ligand PET/CT (¹⁸F-PSMA-1007 PET/CT) to search for new manifestations of prostate cancer, revealing an increased focal uptake (SUV_max, 5.9) in the left cochlear/pericochlear temporal bone and equivocal PSMA-RADS-3a external iliac nodes. Comparison with cone-beam CT and MRI showed that the focal temporal bone uptake corresponded to the typical morphological features of active otospongiosis (otosclerosis) in the context of a previously known long-standing otospongiosis.