Highly efficient and selective extraction of uranium from aqueous solution by a magnetic device: succinyl-ß-cyclodextrin-APTES@maghemite nanoparticles

The removal of radio-elements, notably uranium, from waste-waters is crucial for public health and environmental remediation. To this end, succinyl-ß-cyclodextrin (SßCD) is grafted onto maghemite nanoparticles (NPs) synthesized by the polyol method. The nanocomposite was well characterized. The adsorption of U(VI) by SßCD-APTES@Fe2O3 is pH-dependent with a maximum at pH 6. Adsorption occurs mainly by complex formation and displays a very good selectivity for U(VI) compared to other cations such as Cs+, K+, Na+, Mg2+ and Al3+. The data were plotted according to the Langmuir, Freundlich, Elovich, Temkin and Halsey isotherms. The Langmuir isotherm maximum adsorption capacity (qmax) is 286 mg U g-1 and higher than for other reported sorbents. Moreover, Cs-corrected STEM visualizes the uranium on the NP surface, which is consistent with the Halsey isotherm model for multilayer adsorption. The U(VI) adsorbed on SßCD-APTES@Fe2O3 is easily recovered by magnetic sedimentation and desorption performed in a small volume in order to concentrate the extract. The nanocomposite can be regenerated and re-used at least tenfold

Maghemite nanoparticles bearing di(amidoxime) groups for the extraction of uranium from wastewaters

Polyamidoximes (pAMD) are known to have strong affinities for uranyl cations. Grafting pAMD onto the surface of functionalized maghemite nanoparticles (MNP) leads to a nanomaterial with high capacities in the extraction of uranium from wastewaters by magnetic sedimentation. A diamidoxime (dAMD) specifically synthesized for this purpose showed a strong affinity for uranyl: Ka = 105 M-1 as determined by Isothermal Titration Calorimetry (nano-ITC). The dAMD was grafted onto the surface of MNP and the obtained sorbent (MNP-dAMD) was characterized. The nanohybrids were afterward incubated with different concentrations of uranyl and the solid phase recovered by magnetic separation. This latter was characterized by zeta-potential measurements, X-Ray Photoelectron Spectroscopy (XPS) and X-Ray Fluorescence spectroscopy (XRF), whereas the supernatant was analyzed by Inductively Coupled Plasma coupled to Mass Spectrometry (ICP-MS). All the data fitted the models of Langmuir, Freundlich and Temkin isotherms very well. These isotherms allowed us to evaluate the efficiency of the adsorption of uranium by MNP-dAMD. The saturation sorption capacity (qmax) was determined. It indicates that MNP-dAMD is able to extract up to 120 mg of uranium per gram of sorbent. Spherical aberration (Cs)-corrected High-Resolution Scanning Transmission Electron Microscopy (HRSTEM) confirmed these results and clearly showed that uranium is confined at the surface of the sorbent. Thus, MNP-dAMD presents a strong potential for the extraction of uranium from wastewaters

Iron oxide nanoparticles (Fe3O4, γ-Fe2O3 and FeO) as photothermal heat mediators in the first, second and third biological windows

Nanotherapies are gaining increased interest for the treatment diverse diseases, particularly cancer, since they target the affected area directly, presenting higher efficacy and reduced side effects than traditional therapies. A promising nanotherapy approach is hyperthermia, where the nanoparticle can induce a local temperature increase by an external stimulus in the sick tissue to selectively kill the malignant cells. Among the diverse hyperthermia methods, photothermia is based on the absorption of light by the nanoparticles and further conversion into heat. Within the very wide range of nanostructured photothermal agents, iron oxides offer remarkable features since they are already approved by the FDA/EMA for various biomedical applications, they are biodegradable, easily manipulated using magnetic fields and can be imaged by diverse techniques. Here, we summarize the advantages of using the second biological window, both from the perspective of the skin and the optical properties of iron oxides. Further, we review the photothermal performance of iron oxide nanoparticles in the first, second and third biological windows. Overall, the results show that, for different types of iron oxide nanoparticles (FeO, γ-FeO, wüstite-FeO), both the heating capacity (i.e., induced temperature increase) and the photothermal conversion efficiency, η, vary in a complex way with the light wavelength, depending critically on the measurement conditions and physiochemical properties of the materials. Despite the spread in the reported photothermal properties of iron oxides, FeO particles tend to perform better than their γ-FeO counterparts, particularly in the second biological window. Interestingly, FeO, which has not been exploited so far from a photothermal perspective, shows very appealing absorption properties. Our preliminary studies using FeO/FeO core/shell nanoparticles evidence that they have excellent photothermal properties, outperforming FeO in both first and second biological windows. Finally, some applications beyond cancer treatment of iron oxide nanoparticles, exploiting the enhanced properties in the second spectral window, are discussed

TRAIL-NP hybrids for cancer therapy: a review

IF 7.367International audienceCancer is a worldwide health problem. It is now considered as a leading cause of morbidity and mortality in developed countries. In the last few decades, considerable progress has been made in anti-cancer therapies, allowing the cure of patients suffering from this disease, or at least helping to prolong their lives. Several cancers, such as those of the lung and pancreas, are still devastating in the absence of therapeutic options. In the early 90s, TRAIL (Tumor Necrosis Factor-related apoptosis-inducing ligand), a cytokine belonging to the TNF superfamily, attracted major interest in oncology owing to its selective anti-tumor properties. Clinical trials using soluble TRAIL or antibodies targeting the two main agonist receptors (TRAIL-R1 and TRAIL-R2) have, however, failed to demonstrate their efficacy in the clinic. TRAIL is expressed on the surface of natural killer or CD8+ T activated cells and contributes to tumor surveillance. Nanoparticles functionalized with TRAIL mimic membrane-TRAIL and exhibit stronger antitumoral properties than soluble TRAIL or TRAIL receptor agonist antibodies. This review provides an update on the association and the use of nanoparticles associated with TRAIL for cancer therapy

Design and synthesis of 3-isoxazolidone derivatives as new Chlamydia trachomatis inhibitors.

International audienceChlamydia trachomatis (Ct) is a bacterial human pathogen responsible for the development of trachoma, the worldwide infection leading to blindness, and is also a major cause of sexually transmitted diseases. As iron is an essential metabolite for this bacterium, iron depletion presents a promising strategy to limit Ct proliferation. The aim of this study is to synthesize 3-isoxazolidone derivatives bearing known chelating moieties in an attempt to develop new bactericidal anti-Chlamydiaceae molecules. We have investigated the paths by which these new compounds affect Ct serovar L2 development in HeLa cells, in the presence or absence of exogenously added iron. The iron-chelating properties of these molecules were also determined. Our data reveal important bactericidal effects which are distinguishable from those due to iron chelation

Nano-gold biosynthesis by silica-encapsulated micro-algae : a "living" bio-hybrid material

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Carbon dots, a powerful non-toxic support for bioimaging by fluorescence nanoscopy and eradication of bacteria by photothermia

International audienceCarbon Dots (CDs) are innovative materials which have potential applications in many fields, including nanomedicine, energy and catalysis. Here CDs were produced by the alkali-assisted ultrasonic route and characterized by several techniques to determine their composition and properties. Fluorescence nanoscopy using single-molecule localization microscopy shows that they have very good photophysical properties and a remarkable blinking behaviour at 405 nm. Moreover, these CDs are a safe material, non-toxic towards different cell lines (cancer and non-cancer cells) even at very high concentration, reflecting an excellent biocompatibility. Photothermia, i.e. their heating capacity under laser irradiation, was evaluated at two wavelengths and at several power densities. The resulting temperature increment was high (5 < ΔT < 45 °C) and appropriate for biomedical applications. Bioimaging and photothermia were then performed on E. coli, a Gram(−) bacterium, incubated with CDs. Remarkably, by photothermia at 680 nm (0.3, 1 and 1.9 W cm−2) or 808 nm (1.9 W cm−2), CDs are able to eradicate bacteria in their exponential and stationary phases. Images obtained by 3D super-resolution microscopy clearly show the different CD distributions in surviving bacteria after mild photothermal treatment. These results confirm that CDs are multifunctional materials with a wide range of biomedical applications