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Unlocking the Potential of Organopalladium Complexes for High-Grade Serous Ovarian Cancer Therapy
No full textInternational audienceHigh-Grade Serous Ovarian Cancer (HGSOC) is the most common and lethal subtype of ovarian cancer, known for its high aggressiveness and extensive genomic alterations. Typically diagnosed at an advanced stage, HGSOC presents formidable challenges in drug therapy. The limited efficacy of standard treatments, development of chemoresistance, scarcity of targeted therapies, and significant tumor heterogeneity render this disease incurable with current treatment options, highlighting the urgent need for novel therapeutic approaches to improve patient outcomes. In this study we report a straightforward and stereoselective synthetic route to novel Pd(II)-vinyl and -butadienyl complexes bearing a wide range of monodentate and bidentate ligands. Most of the synthesized complexes exhibited good to excellent in vitro anticancer activity against ovarian cancer cells. Particularly promising is the water-soluble complex bearing two PTA (1,3,5-triaza-7-phosphaadamantane) ligands and the Pd(II)-butadienyl fragment. This compound combines excellent cytotoxicity towards cancer cells with substantial inactivity towards non-cancerous ones. This derivative was selected for further studies on ex vivo tumor organoids and in vivo mouse models, which demonstrate its remarkable efficacy with surprisingly low collateral toxicity even at high dosages. Moreover, this class of compounds appears to operate through a ferroptotic mechanism, thus representing the first such example for an organopalladium compound
In situ copper isotope analysis by femtosecond Laser Ablation MultiCollector Inductively Coupled Plasma Mass Spectrometry (fs-LA-MC-ICP-MS) on historical gold coins
No full textInternational audienceThis study investigates the potential of femtosecond laser ablation coupled with multicollector inductively coupled plasma mass spectrometry (fs-LA-MC-ICP-MS) for copper isotopic analysis in gold matrices applied to cultural heritage. Elemental analyses, which have commonly been used so far, provide information on the circulation of metal stocks based on elemental signatures but fail to pinpoint the precise source of gold. In contrast, isotopic analyses can offer a more accurate means of identifying the source of the metal, yet their application to gold matrices remains a challenge. For the first time, we successfully determined copper isotope ratio in gold matrices and achieved repeatabilities of 0.12‰ to 0.26‰ (2SD) for δ65Cu analyses carried out over up to 8 days, demonstrating the feasibility of copper isotopic analyses in gold coins at the micron-scale. This work was conducted using isotopically characterised in-house matrix-matched gold standard with copper concentrations varying from 4.5 wt% to 9.6 wt%. Our results open new avenues of research for provenance studies of precious museum artefacts and archaeological finds, with potential applications in authentication analyses on similar gold materials. The micro-sampling performed by femtosecond laser ablation minimises the damages on such ancient artifacts. However, the Cu concentrations had to be of at least 4 wt% with our analytical set up and a special care must be taken on the laser beam focusing in order to obtain accurate δ65Cu measurements in gold matrices
Obtaining V2(PO4)3 by sodium extraction from single-phase Na<sub><i>x</i></sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> (1 < x < 3) positive electrode materials
No full textLa version soumise (de l'article) déposée porte un titre différentInternational audienceWe report on single-phase NaxV2(PO4)3 compositions (1.5 ≤ x ≤ 2.5) of the Na super ionic conductor type, obtained from a straightforward synthesis route. Typically, chemically prepared c-Na2V2(PO4)3, obtained by annealing an equimolar mixture of Na3V2(PO4)3 and NaV2(PO4)3, exhibits a specific sodium-ion distribution (occupancy of the Na(1) site of only 0.66(4)), whereas that of the electrochemically obtained e-Na2V2(PO4)3 (from Na3V2(PO4)3) is close to 1. Unlike conventional Na3V2(PO4)3, when used as positive electrode materials in Na-ion batteries, the NaxV2(PO4)3 compositions lead to unusual single-phase Na+ extraction/insertion mechanisms with continuous voltage changes upon Na+ extraction/insertion. We demonstrate that the average equilibrium operating voltage observed upon Na+ deintercalation from single-phase Na2V2(PO4)3 is increased up to an average value of ~3.70 V versus Na+/Na (thanks to the activation of the V4+/V5+ redox couple) compared to 3.37 V versus Na+/Na in conventional Na3V2(PO4)3, thus leading to an increase in the theoretical energy density from 396.3 Wh kg–1 to 458.1 Wh kg–1. Electrochemical and chemical Na+ deintercalation from c-Na2V2(PO4)3 enables complete Na-ion extraction, increasing energy density
Li3V2(PO4)3 sintering atmosphere optimisation for its integration in all-solid-state batteries
No full textInternational audienceIntegration of active materials into the architecture of all-solid-state batteries represents a significant scientific inquiry. Li3V2(PO4)3 (LVP), a positive and negative electrode active material for Li-ion batteries, has been subject to extensive research to elucidate its electrochemical behaviour during cycling processes. However, the comprehensive analysis of its thermal behaviour under different sintering atmosphere conditions has remained underexplored, particularly in the context of its compatibility with solid electrolytes. This study presents a meticulous study of sintering process under different atmospheres with precise control over oxygen partial pressure. Interestingly, we were able to sinter LVP and obtain dense, pure ceramic phase under slightly oxidising atmosphere, characterized by conductivity properties analogous to those observed in samples sintered under Ar/H2 conditions. The findings of this investigation contribute to the understanding of the optimal conditions required for the sintering of LVP, paving the way for the co-sintering of this material with inorganic solid electrolyte unstable under reducing atmosphere, such as LATP
Metal‐Catalyzed Cross‐Coupling for the Synthesis of β‐Lactam Drugs and Related Chemical Probes
No full textInternational audienceAntimicrobial resistance is a major public health threat, due to the emergence of new bacterial strains not responding to classical antibiotics. This review focuses on the use of transition metal cross‐coupling strategies used to access new β‐lactam derivatives, the most well‐known and commonly used antibiotics. This manuscript covers the seminal studies for the synthesis of antibiotics up to the current need of accessing specific probes (by functionalizing existing drugs), crucial for the detection of resistances. These strategies also allow the linkage of a cargo to a β‐lactam antibiotic for selective release for either therapeutic effect or for diagnostic purposes (in the case of probes), which will be explained in this article
Insights into the intricate charge photoaccumulation in a polyoxometalate–bodipy covalent hybrid
No full textInternational audienceSolar fuel generation relies on the catalysis of multielectron, multiproton reactions facilitated in nature by charge accumulation in electron relays like NADPH or hydroquinone. Here, we demonstrate the light-driven charge accumulation in a noble-metal-free photochemical dyad comprising a bodipy photosensitizer linked to a Dawson polyoxometalate (POM) using triethylamine (TEA) as sacrificial electron donor. Under visible light irradiation, the hybrid dyad accumulates up to two electrons on the POM, achieving complete conversion within few minutes. The first reduction proceeds rapidly and efficiently while the second electron is introduced more slowly through an intricate, multi-pathway mechanism that we inferred through combined spectroscopy, electrochemistry and theoretical calculations. The formation of the two-electron reduced species is enhanced in the presence of trifluoroacetic acid by virtue of proton-coupled electron transfer (PCET) as well as by promoting the dismutation of the one-electron reduced POM. Simultaneously, POM reduction may also take place via a light-independent route involving the reactive TEA radical byproduct, effectively rendering TEA an overall two-electron, one-proton donor. The stored redox equivalents in the POM were demonstrated to activate oxygen but also to be engaged in PCET to substrates such as 1,4-benzoquinone, highlighting the potential utility of POM–photosensitizer hybrids in solar fuel-related transformations
Reducing strain in CVD diamond films for quantum applications through substrate engineering and surface treatment
No full textInternational audienceThe development of high-quality CVD (Chemical Vapor Deposition) diamond films is of growing interest for advanced applications in quantum technologies, spintronics, and sensing. A key challenge in this context is the reduction of internal strain in the diamond layers, particularly in nitrogen-doped films where stress directly impacts the spin coherence time (T2*), a critical parameter for quantum performance.This study focuses on substrate engineering and surface treatment as strategies to reduce strain and enhance single-crystal diamond film quality. Indeed, previous findings demonstrated the role of substrate patterning such as hole formation which significantly reduces dislocation densities [1], while structuring the substrate into pyramidal shapes influences growth dynamics and defect formation [2]. This substrate engineering clearly impacts stress distribution within the film. Building on these approaches, we implemented a combination of substrate modifications, followed by chemical etching (aqua regia, plasma H₂/O₂) and polishing.The effect of substrate modifications on stress distribution was assessed using birefringence imaging (Figure 1). The results show that defects initially present in the substrate propagate into the grown layer, highlighting the influence of the initial substrate quality on the final film. Additionally, the impact of polishing on stress distribution was analyzed using DiamondView and birefringence imaging (Figure 2), revealing stress patterns.These steps preceded CVD diamond growth under optimized conditions, with the aim being to significantly improve T2* in nitrogen-doped layers, offering promising prospects for diamond-based devices in quantum technologies, electronics, and sensing. Additionally, this study has the objective to underscore the pivotal role of substrate design in optimizing the performance of synthetic diamond-based materials, particularly in the quantum technologies area.References [1] A. Tallaire et al. , Adv. Mater. 2017, 29,1604823.[2] A. Tallaire et al. , Diamond and Related Material,Volume 33,2013
Self-assemblies of cell-penetrating peptides and ferrocifens: design and biological evaluation of an innovative platform for lung cancer treatment
No full textInternational audienceChemotherapy currently used for lung cancer treatment often consists in a combination of drugs, with a moderate efficacy and severe side effects. A major drawback of the classical inorganic drugs used is their hydrophobicity, leading to a very low blood availability and a weak efficacy. To overcome this constraint, a nanoplatform was set up in order to vectorize a ferrocifen drug, an organometallic tamoxifen derivative known for its really potent in vitro activity, but as well for its poor water solubility. Two different ferrocifens were tested: P54 and P819. The covalent conjugation of a cell-penetrating peptide (CPP) to the ferrocifen was performed, leading to an amphiphilic prodrug, potentially able to self-assemble. The CPP used in this study are polyarginines and RLW. Moreover, in order to bring stealth and mucopenetration properties, polyethylene glycol (PEG) was incorporated into the nanostructure. The co-nanoprecipitation of CPP-ferrocifen and PEG-ferrocifen was investigated to obtain self-assemblies. A comparison of the biological activity of the different suspensions was assessed in vitro on a healthy cell line and on two different lung cancer cell lines. The biological activity of P54 was increased by a factor 9 with the Arg9-P54 suspension, by increasing the cell internalization. Moreover, the P54 based-self-assemblies were chosen to test their in vivo activity on mice bearing lung tumor. The results showed that the intratracheal nebulization of Arg9-P54/PEG-P54 or of Arg9-P54 suspensions slowed up significantly the evolution of lung cancer in mice: the suspension with PEG bringing an additional comfort to the animal at the administration
Mechanically robust eutectogels enabled by precisely engineered crystalline domains
No full textInternational audienceEutectogels have emerged as promising candidates for technological applications due to their environmental stability, repeatable deformability, and high ionic conductivity. Nevertheless, the existing eutectogels often show fragile network structures, in which the simultaneous achievement of high modulus, strength, and toughness remains a real challenge. Herein, a variabletemperature solvent exchange (VTSE) strategy is proposed to fabricate mechanically robust eutectogels. The VTSE approach implements a two-stage solvent exchange process to synergistically optimize the crystal nucleation and growth of poly(vinyl alcohol), resulting in a robust network crosslinked by well-developed crystalline domains. The obtained eutectogels exhibit an advantageous combination of high Young's modulus (103.1 MPa), strength (40.5 MPa), toughness (86.8 MJ m -3 ), and fracture energy (98.7 kJ m -2 ), surpassing the performance of conventional hydrogels, organogels, and ionogels. Moreover, the versatility of VTSE approach allows its application to other solvent systems, providing a powerful platform for the design of advanced functional gels.High-performance gels with good mechanical properties and environmental stability are in great demand for a wide range of applications. In biomedical engineering, load-bearing tissue scaffolds require gels with high modulus and strength to mimic the mechanical performance of natural tissues 1-4 . In energy storage devices, gel electrolytes with adequate toughness and environmental stability are essential for ensuring safety and durability of flexible supercapacitors and batteries 5-8 . Furthermore, the development of stretchable and wearable electronics necessitates mechanically robust gels that possess favorable fatigue resistance to withstand repeated deformations 9-11 . Nonetheless, conventional gels, such as hydrogels, organogels, and ionogels, often fail to meet these stringent requirements due to their inherent shortcomings, including inadequate mechanical strength, poor environmental stability, high cost, and toxicity 12-14 . Eutectogels, defined as polymer networks swollen with liquid deep eutectic solvent (DES) as the continuous phase, have recently emerged as a promising class of gels to address these limitations 15-17 . DES is a mixture of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) featuring negligible volatility, high thermal stability, wide electrochemical window, and good conductivity 18,19 . These properties endow eutectogels with versatility, making them attractive candidates for various applications. Moreover, the facile preparation of DES by mixing two or more components offers a cost-effective and eco-friendly platform for fabricating advanced functional gels 20 . Nevertheless, simultaneously achieving high modulus, strength, and toughness in eutectogels remains a huge challenge, stemming from conflicting structural requirements. High modulus and strength typically demand densely crosslinked networks with restricted chain mobility, whereas high toughness necessitates energy dissipation mechanisms (e.g., sacrificial bonds or chain sliding) that often compromise stiffness 21,22 .In the pursuit of high-performance gels, researchers have explored various tactics, such as inducing abundant polymer chain entanglements 22,23 , constructing dynamic crosslinked networks 24,25 , elaborating bio-inspired multi-scale tough composites 26,27 , and </div
Coupled quartz crystal microbalance – Surface enhanced Raman scattering strategy for the design and testing of aptasensors for small analytes
No full textInternational audienceBoth quartz crystal microbalance with dissipation (QCM-D) and Surface Enhanced Raman Scattering (SERS) stand at the forefront of label-free transducing techniques to trace and monitor biomolecular association events occurring at solid-liquid interfaces. Although these techniques provide highly complementary information on thin films' structure and molecular composition, they have never been simultaneously coupled in a single sensor element. We report herein the design of nanostructured gold-coated quartz crystal sensors acting as bimodal transducer elements to subsequentially or even in parallel and in situ monitor biomolecular recognition events by QCM-D and SERS. As a proof-of-concept, this bimodal sensor was applied to investigate the interaction between a chemisorbed DNA aptamer and a small molecule target, the antibiotic streptomycin. Combined QCM-D and SERS measurements provided evidence of successful engineering of the aptamer sensing layer as well as thermodynamic and structural information on the subsequent binding of streptomycin. QCM-D data enabled the measurement of a dissociation constant KD of 23±4 nM for the binding of streptomycin to the aptamer with a number of binding sites roughly equal to one. SERS data confirmed the conformational change of the aptamer upon interaction with streptomycin and indicated the nucleotides possibly involved in its recognition