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Designing and manufacturing multifunctional nanoparticles (NPs) are of considerable interest for both academic and industrial research. Among NPs used in this field, iron oxide NPs show low toxicity compared to metallic ones and are thus of high interest for biomedical applications. In this work, superparamagnetic Fe3−δO4-based core/shell NPs were successfully prepared and characterized by the combination of different techniques, and their physical properties were investigated. We demonstrate the efficiency of the layer-by-layer process to graft polyelectrolytes on the surface of iron oxide NPs. The influence of the polyelectrolyte chain configuration on the magnetic properties of the Fe3−δO4/polymer core/shell NPs was enlightened. The simple and fast process described in this work is efficient for the grafting of polyelectrolytes from surfaces, and thus, derived Fe3−δO4 NPs display both the physical properties of the core and of the macromolecular shell. Finally, the cytotoxicity toward the human THP-1 monocytic cell line of the core/shell NPs was assessed. The results showed that the polymer-capped Fe3−δO4 NPs exhibited almost no toxicity after 24 h of exposure at concentrations up to 25 μg mL–1. Our results show that these smart superparamagnetic nanocarriers with stealth properties are promising for applications in multimodal cancer therapy, including drug delivery.

International audience; Antimony (Sb) is a naturally occurring element; it is enriched in the environment by anthropogenic activities. Like other metalloid species, Sb partitions to mineral phases such as oxyhydroxides. In reducing environments, Fe(III) may serve as a terminal electron acceptor during dissimilatory iron reduction leading to its transformation. Relatively little is known concerning the effect of Sb(V) on the precipitation of biogenic minerals in relation to microbiologically mediated redox reactions. To further our understanding, Sb-bearing ferrihydrites (0.5 g) with variable Sb/(Fe + Sb) molar ratios of 0.04, 0.06 and 0.1, were incubated in the presence of Shewanella oneindensis MR-1 (1 × 108 cell mL−1) under N2 atmosphere. Additionally, we synthesized abiotic GR1(CO32−) in the presence of Sb(V) to examine the effect of Sb(V) on this mineral formation and stabilization. A combination of wet chemistry and solid analysis techniques (XRD, Mössbauer and Raman spectroscopies) was used to characterize the reactions.The Sb loading affected the rate and the extent of bio-reduction compared with pure ferrihydrite. Only a minor fraction of the total Sb, less than 0.5%, was released into the solution by the end of the incubation period, suggesting that the metalloid partitioned mainly in a newly formed phase. Furthermore, XPS analyses showed the presence of Sb(V) and Sb(III) species on the biogenic minerals. Magnetite was the main biogenic precipitate (91%) in the absence of Sb(V). Increasing of the molar ratios [Sb/(Fe + Sb)] to 0.1 resulted mainly in the precipitation of carbonated green (47%) rust and goethite (37%). Abiotic green rust synthesis carried out in the presence of Sb(V) indicated the latter’s stabilizing effect on the green rust structure, as for phosphate species. Thus, it is likely that Sb(V) preserve biogenic green rust, hindering its transformation to more thermodynamically stable phases.

International audience; This study reports on the development of thermoresponsive core/shell magnetic nanoparticles (MNPs) based on an iron oxide core and a thermoresponsive copolymer shell composed of 2-(2-methoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol)methacrylate (OEGMA) moieties. These smart nano-objects combine the magnetic properties of the core and the drug carrier properties of the polymeric shell. Loading the anticancer drug doxorubicin (DOX) in the thermoresponsive MNPs via supramolecular interactions provides advanced features to the delivery of DOX with spatial and temporal controls. The so coated iron oxide MNPs exhibit superparamagnetic behavior with a saturation magnetization of around 30 emu g–1. Drug release experiments confirmed that only a small amount of DOX was released at room temperature, while almost 100% drug release was achieved after 52 h at 42 °C with Fe3−δO4@P(MEO2MA60OEGMA40), which grafted polymer chains displaying a low critical solution temperature of 41 °C. Moreover, the MNPs exhibit magnetic hyperthermia properties as shown by specific absorption rate measurements. Finally, the cytotoxicity of the core/shell MNPs toward human ovary cancer SKOV-3 cells was tested. The results showed that the polymer-capped MNPs exhibited almost no toxicity at concentrations up to 12 μg mL–1, whereas when loaded with DOX, an increase in cytotoxicity and a decrease of SKOV-3 cell viability were observed. From these results, we conclude that these smart superparamagnetic nanocarriers with stealth properties are able to deliver drugs to tumor and are promising for applications in multimodal cancer therapy.

International audience; The present work reports on the low-pressure, radio-frequency, plasma-driven synthesis of ε-Fe 3 N-type nano-particles homogeneously deposited on a high-surface-area porous carbon support, with tunable magnetic properties, directly depending on the plasma treatment conditions. Iron nanoparticles are formed from the degradation of a solid organometallic precursor mixed with a carbon xerogel in a nitrogen-containing (argon/ammonia) plasma discharge. Variation of the working pressure during the plasma treatment directly affects the residence time of the reactive species, which determines the crystalline state of the nanoparticles, from amorphous at low-pressure treatment to well crystallized at high-pressure treatment. This results in a direct influence of the magnetic properties of the iron nitride nanoparticles. The working pressure results in two competing effects because it enhances the crystallinity (at higher pressure) and also slightly affects the surface chemistry of the nanoparticles by increasing the oxygen content, while the last is believed to deteriorate the magnetic properties; however, the crystallinity enhancement dominates. The synthesized Fe x N/C XG magnetic composites have been applied as filler materials in alginate membranes for ethanol dehydration in a pervaporation experiment. Results indicate a considerably enhanced performance of the alginate membrane as determined by its selectivity, the separation index, and the flux even when using a small Fe x N/C XG loading (3% w/w).

The development of catalysts as an alternative to platinum group metals (PGMs) has great importance to improve the efficiency of hydrogen evolution reaction (HER). Herein, the novel amorphous ternary refractory metal selenides (MWSex; M = Co and Ni), which were synthesized by hot-injection approach, were firstly investigated on the electrocatalytic HER in alkaline media. Optical, electrochemical and magnetic properties of the electrocatalysts were explored, as well as the chemical structures and morphologies. These results clearly show that the obtained materials are having the amorphous crystal structure and are shaped as spherical and rod-like structures. Moreover, the addition of Ni and Co metals into the WSex structure were raised the catalytic activity of HER comparing to that of only WSex. This work paves the way for the exploration of copper-based amorphous selenides as electrocatalysts for the hydrogen evolution in order to replace noble metal Pt. © 2019 Elsevier B.V., 32-M-16 Türkiye Bilimler Akademisi 215M309, The authors would like to thank TUBITAK (The Scientific and Technological Research Council of Turkey ) (Grant number: 215M309 ), Karamanoglu Mehmetbey University , Scientific Research Foundation (Grand Number: 32-M-16 ) and Turkish Academy of Sciences via a TUBA-GEBIP fellowship for supporting this work. Appendix A