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Les complexes biphényle-or(III) : un squelette prometteur dans la lutte contre le cancer
No full textBiphenyl-gold(III) complexes: a promising scaffold in the fight against cancer. Organometallic gold(III) complexes have attracted a large attention as potential anticancer agents in the last decades. The main advantage of organometallic complexes is their high redox stability in physiological media due to the presence of Au-C bounds. In this respect, bis-cyclometalated [(C^N^C)AuL]+ complexes have demonstrated great potential. However, their main limitations are the large number of coordination site occupied by the pincer ligands, leaving only one or no coordination sites available for other ligands. To enlarge the scope of structures that can be evaluated and potentially explore new modes of actions while preserving the high redox stability of bis-cyclometalated complexes, a reorganization of their coordination sphere appeared highly promising. Using a biphenyl ligand giving two Au-C bounds would preserve the high redox stability of bis-cyclometalated complexes while offering two coordination sites available for various ligands to optimize the anticancer properties of the complexes. Thus, this scaffold led to structures ranging from very labile which activity is due to one decoordinated ligand to hemilabile complexes and up to highly stable complexes in cellulo for which the active principle is the native cationic complex
Synergistic effects of carbon coating on Na2Ti3o7 anodes: from sodium storage to surface stabilization
No full textInternational audienceSodium metatitanate (Na2Ti3O7) is a promising anode material for sodium-ion batteries due to its abundance, low insertion potentials, and high crystal density, which favors the production of electrodes with a high volumetric energy density. However, its performance is limited by a low initial Coulombic efficiency (iCE), a rapid decrease in capacity during cycling, and a strong dependence on conductive additives. To address these challenges, a carbon coating has been applied via chemical vapor deposition (CVD) using acetylene at different temperatures and treatment times. A uniform and homogeneous carbon layer with a thickness ranging from 5.5 to 38 nm was achieved by increasing the CVD temperature and time while maintaining a relatively small specific surface area. The increase in the carbon content deposited (1.5–12.7%) progressively improved the performance, including an enhanced iCE (from 23% to ∼70%), an increase in initial capacity (from 45 to ∼132 mAh g–1), and better capacity retention (49 mAh g–1 after 50 cycles at a rate of 1 C), with the best performance achieved at 600 °C for 6 h. The carbon coating improves the performance of Na2Ti3O7 by modifying the SEI composition. It reduces the Na2CO3 amount and favors NaF formation, ensuring a robust and ionically conductive SEI. The carbon coating boosts the electronic conductivity, favoring charge transfer. This dual effect reduces electrolyte decomposition, increases efficiency, and enhances capacity. It is shown that Na+ storage occurs via reversible intercalation with the formation of Na4Ti3O7. Limited structural degradation occurs, with the C coating significantly improving the cycle stability
Electrode shading lithography: A new method to avoid side dissolution of adhesion layer during electrodeposition of platinum black
No full textInternational audienc
Light-Induced Regioselective 6-Endo versus 5-Exo Cycloisomerization of o-Alkynylbenzoic Acids
No full textInternational audienceRegioselectivity of the gold(I)-catalyzed cycloisomerization of o-alkynyl benzoic acids is significantly influenced by blue LEDs irradiation. In particular, the reaction exhibits higher selectivity toward the 6-endo regioisomer when irradiated with blue light, whereas the 5-exo product is obtained as the major product in the absence of light. These findings prompted mechanistic inquiries that we sought to address through running the reactions in diverse conditions and also by studying the reactivity of the vinylgold(I) complexes that are formed as intermediates
Oxygen in diamond: Thermal stability of ST1 spin centres and creation of oxygen-pair complexes
No full textInternational audienc
Organelle-Targeting Iridium(III) Benzothiazole Complexes Potently Induce Immunogenic Cell Death for Gastric Cancer Immunotherapy
No full textInternational audienceDespite being the mainstay for gastric cancer treatment, conventional therapies such as surgery, chemotherapy, and radiotherapy suffer from substantial limitations that compromise their efficacy and patients’ quality of life. To overcome these challenges, innovative strategies and novel combination therapies are urgently needed. Herein, we report a series of organelle-targeting iridium(III) benzothiazole complexes designed to localize in mitochondria, lysosomes, the endoplasmic reticulum, and the Golgi apparatus. Among them, the mitochondria- and lysosome-targeting complexes demonstrated potent cytotoxicity against gastric cancer cells and induced distinct nonapoptotic cell death pathways, ultimately leading to immunogenic cell death. Given the inadequacy of conventional methods to decipher the immunomodulatory effects of metallodrugs in the tumor immune microenvironment (TME), we employed time-of-flight mass cytometry (CyTOF) to achieve a comprehensive profiling of immune cell subsets. This work provides a multidimensional characterization of TME remodeling by organelle-targeted Ir(III) complexes, offering valuable insights for developing metal-based chemoimmunotherapeutics
Self-assemblies from prodrugs composed of antimicrobial peptides: a revolution in local lung cancer treatment, with microbiota as a main actor
No full textInternational audienceHuman microbiota is now recognized as a fundamental organ of the body. In its healthy state, it fulfills essential local and systemic functions, whereas dysbiosis disrupts these roles and can contribute to disease. Although numerous studies have examined the relationship between microbiota and cancer, often revealing conflicting mechanisms and outcomes, this work has focused almost exclusively on the gut, leaving the lung microbiota largely unexplored. In this project, a ferrocifen compound was selected as an anticancer agent for lung cancer therapy. We found that lung microbiota actively degraded the ferrocifen. To prevent this degradation, the antibacterial peptide buforin II was synthesized, purified, and characterized. After confirming its antimicrobial activity, it was covalently conjugated to the ferrocifen, yielding an amphiphilic bioconjugate. This prodrug was subsequently formulated into self-assembled structures to enhance ferrocifen solubility and bioavailability. The resulting self-assemblies were evaluated in an orthotopic murine model of lung cancer and administered via nebulization to assess their therapeutic efficacy. A significant reduction in tumor progression and an improved predicted survival in mice were obtained. Together, these findings highlight the capacity of the lung microbiota to interfere with anticancer therapies and underscore the importance of considering this flora when designing treatment strategies for lung cancer
Exploring processability limitations of commercial hard carbon for negative electrodes of Na-ion batteries
No full textInternational audienceOptimizing electrode manufacturing processes for sodium-ion batteries (SIBs) is crucial for enhancing their performance and commercial viability. This study systematically investigates the influence of critical electrode fabrication parameters, including solid content, mass loading, and calendering, on commercial hard carbon (HC) electrode properties. Slurries prepared with 35 % and 40 % solid content (SC) demonstrated distinct rheological behaviours, directly affecting electrode mechanical stability and processability. The slurry with SC-35 % provided a better balance between manageable viscosity and robust mechanical stability upon drying, whereas SC40 % slurry exhibited higher viscosity, particle agglomeration, and poorer electrode mechanical integrity. Calendering was studied at compression degrees of 10 %, 20 %, and 30 %, revealing limited effectiveness in reducing porosity due to the intrinsic mechanical properties of HC, whereas, higher compression degrees led to structural damage. Electrochemical studies conducted in half-cells (HC vs. Na) and full-cells (HC vs. Na3V2(PO4)3) clearly indicated better electrochemical performance at moderate calendering degrees (10-20 %), effectively balancing mechanical integrity and electrical conductivity. This comprehensive study results in a useful experimental database in academic literature, underscoring the importance of precise control over slurry formulation and calendering parameters to achieve structurally robust electrodes, thus significantly enhancing the practical performance of SIBs
Dual corrosion-control mechanisms induced by calcium concentration in Mg-Ca alloys for Mg-Air batteries
No full textInternational audienceThe role of calcium (Ca) in the corrosion behavior of Mg-Ca alloys, particularly in the context of Mg-air batteries, remains a critical area of research. This study demonstrates the dual mechanisms of the corrosion resistance of Mg-Ca alloy influenced by Ca. Electrochemical analysis and surface characterization via time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to elucidate Ca's impact on both the anodic dissolution kinetics and the stability of corrosion layer. Results reveal that Ca simultaneously promotes and mitigates corrosion, depending on Ca concentration. At a lower Ca concentration (Mg-0.2Ca), the formation of a dense and protective oxide/hydroxide layer effectively suppresses corrosion, whereas higher Ca content (Mg-2Ca) promotes severe micro-galvanic corrosion, accelerating the alloy degradation. Full-cell discharge tests at 2 mA/cm² further demonstrate that Mg-0.2Ca exhibits the highest energy density of 1529 Wh/kg, significantly outperforming Mg-2Ca, which delivers an energy density of 889 Wh/kg. These findings provide critical insights into the interplay between alloy composition, corrosion mechanisms, and electrochemical performance, offering a scientific foundation for optimizing the discharge performance of Mg-Ca alloys and for achieving a better understanding of their working mechanisms
Wide-Surface Furnace for In Situ X-Ray Diffraction of Combinatorial Samples using a High-Throughput Approach
No full textThe combinatorial approach applied to functional oxides has enabled the production of material libraries that formally contain infinite compositions. A complete ternary diagram can be obtained by pulsed laser deposition (PLD) on 100 mm silicon wafers. However, interest in such materials libraries is only meaningful if high-throughput characterization enables the information extraction from the as-deposited library in a reasonable time. While much commercial equipment allows for XY-resolved characterization at room temperature, very few sample holders have been made available to investigate structural, chemical, and functional properties at high temperatures in controlled atmospheres. In the present work, we present a furnace that enables the study of 100 mm wafers as a function of temperature. This furnace has a dome to control the atmosphere, typically varying from nitrogen gas to pure oxygen atmosphere with external control. We present the design of such a furnace and an example of X-ray diffraction (XRD) and fluorescence (XRF) measurements performed at the DiffAbs beamline of the SOLEIL synchrotron. We apply this high-throughput approach to a combinatorial library up to 735 °C in nitrogen and calculate the thermal expansion coefficients (TEC) of the ternary system using custom-made MATLAB codes. The TEC analysis revealed the potential limitations of Vegard’s law in predicting lattice variations for high-entropy materials