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Mutated sigma-1R disrupts cell homeostasis in dHMN patient cells
No full textInternational audienceHereditary-Motor-Neuropathies (dHMNs) are clinically and genetically heterogeneous neurological disorders characterized by degeneration of peripheral motoneurons. We previously identified two sigma-1 receptor (Sigma-1R) variants (p.E138Q; p.E150K) in dHMN Italian patients that behave as “loss-of-function” mutations in neuroblastoma cell lines. Here, we characterize the functional effects of Sigma-1R mutation in primary fibroblasts from homozygous patients bearing the E150K mutation, and matched controls, by performing biochemical, gene expression, immunofluorescence and Ca 2+ imaging analysis. Our results show that Sigma-1R expression and distribution is significantly altered in patient fibroblasts. Moreover, patient cells present a general derangement of cell homeostasis as revealed by impairment of global Ca 2+ dynamics, disorganization of the ER-mitochondria tethers, enhancement of the autophago-lysosomal pathway and blunting of mitochondrial aerobic metabolism compared to controls. These findings highlight the crucial role of Sigma-1R in the maintenance of cell and protein homeostasis, inter-organelle communication and intracellular Ca 2+ signalling, supporting the notion that Sigma-1R is protective for motor neuron activity and its down-regulation and/or loss-of-function, as in the case of the E150K mutation, might play the key role in the neuronal degeneration in dHMN patients
Impact of Chelation on Reactivity and Cytotoxicity of Hemilabile Biphenyl Gold(III) N‐Heterocyclic Carbene Complexes
No full textInternational audienceAlthough great progresses have been accomplished in the field of antineoplastic treatments, the need for chemotherapy agents with new mechanisms of action remains essential. Metal complexes presenting hemilabile ligands could combine structural toxicity upon full coordination of the ligand and reactive toxicity upon ligand partial decoordination and direct coordination of the metal center to biological targets. To investigate the relevance of hemilability in the case of Au(III) complexes, we synthesized eight open biphenyl gold(III) N‐heterocyclic carbene complexes coined BGC of general formula [(C^C)Au(NHC^het)Cl] where het is a pyridine‐type entity and C^C is 4,4′‐diterbutylbiphenyl. Chloride abstraction afforded the chelated cationic complexes [(C^C)Au(NHC^N)]PF 6 in which the pyridine arm coordinates the gold ion. Quantitative irreversible conversion of the cationic forms to the neutral ones in the presence of chloride ions was demonstrated through extensive speciation studies by 1 H NMR spectroscopy on both forms in different media including DMSO/cell culture medium mixture. The BGC complexes exhibited antiproliferative activity in the low micromolar range with equivalent activities for each open neutral/chelated cationic pair. Time lapse fluorescence videomicroscopy studies demonstrated the activation of effector caspases 3/7, suggesting the induction of apoptosis. Preliminary mechanistic studies suggest that apoptotic cell death may arise partially from mitochondrial membrane depolarization
Atomic Layer Deposition of Spinel Bimetallic Oxides for Enhanced Photoelectrochemical Energy Conversion
No full textSymposia D: Next-Generation Solar Technologies: unconventional materials and sustainable innovations for photovoltaic, photoelectrochemical and photocatalytic systemsInternational audiencePhotoelectrochemical cells (PECs) are attracting growing interest for their ability to generate hydrogen (H2) as a solar fuel by water dissociation. This provides efficient solution for renewable energy production compared with Electrolysis, Steam Methane Reforming, etc. The intermediate PEC technology offers a balance, with moderate complexity and better prospects for robustness and longevity [5]. Among the various electrode materials studied in the literature [1], [2], [3], oxide semiconductors (SCs) are particularly promising for their abundance, low cost, and superior stability compared to other semiconductors. However, they present certain challenges, including limited absorption in the visible range, low electrical conductivity, weak charge transfer kinetics, and carrier transport that can be challenging to improve. Binary oxides emerge as an interesting metal-oxide option with potential applications in photocatalysis [4]. However, achieving precise control over the atomic ratio remains a significant challenge.To address these challenges, Atomic Layer Deposition (ALD) is employed to develop innovative photoelectrodes using bimetallic oxides, such as FexCo3-xO4 with a spinel structure, which offer tunable optical and electrical properties, along with improved thermal stability and catalytic activity [6]. The process starts with the individual processing of Co and Fe oxides followed by their integration into a bimetallic oxide through the ALD supercycle strategy at 200 °C supported by post annealing. Structural characterizations were performed on single metal oxides followed by Raman, UV-VIS, ellipsometry and FTIR measurements. After establishing the relationships between the synthesis parameters, structural properties, and optoelectronic characteristics of these monometallic oxides, a bimetallic oxide was grown successfully. The relationships between the synthesis parameters, structural properties, and optoelectronic characteristics optical absorption of FexCo3-xO4 were thoroughly examined.Following the successful synthesis of the spinel bimetallic oxide FexCo3-xO4, we will integrate them with our previously prepared Nb-TiO₂[7] to form a PN-type photoelectrode (photoanode). Optical and electrical characterizations will be performed to assess the photogeneration and carrier transport properties before photoelectrocatalytic activity measurement
Nanoparticules d'or stabilisées par des polyoxotungstates : comment passer d'une suspension aqueuse à CH3CN ?
No full textInternational audienceThe present study aims to evaluate available methods for preparing suspensions of gold nanoparticles stabilized by polyoxometalates (POMs@AuNPs) in CH3CN, a solvent commonly used in oxidation reactions. POMs@AuNPs are successfully synthesized in CH3CN using three different approaches: i) in situ generation of nanoparticles via chemical reduction of the HAuCl4 precursor with various reducing agents in CH3CN in the presence of POMs; ii) formation of POMs@AuNPs by reducing HAuCl4 with NaBH4 in the presence of [PW11O39]7− or [AsW9O33]9− in aqueous solution, followed by transfer into CH3CN after centrifugation; and iii) transfer of aqueous suspensions of Au0 nanoparticles, obtained by reducing HAuCl4 with NaBH4 and subsequent centrifugation, into CH3CN, followed by the addition of soluble organic salts of [PW12O40]3− or [AsW9O33{PO(CH2)2CO2H}2]5−. These strategies, inspired by literature, are used to assess their strengths and limitations regarding translation to CH3CN. The resulting suspensions are characterized by UV-Vis spectroscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy analysis, dynamic light scattering, and zeta potential measurements. The most stable suspensions are obtained by transferring an aqueous suspension initially stabilized with a mixture of citrate ions and tannic acid into acetonitrile. Subsequent exchange with polyoxometalates in CH3CN results in negligible changes in nanoparticle size or suspension stability
Structural Features and Photophysical and Antiproliferative Properties of Me<sub>2</sub>N-pbt-Cycloplatinated Complexes with Picolinate Ligands
No full textInternational audience2-(4-dimethylaminophenyl)benzothiazolate (Me2N-pbt)-cyclometalated platinum complexes containing four different picolinate ligands, [Pt(Me2N-pbt)(R-pic-κN∧O)] (R = 3-H 1, 3-NH2 2, 3-OH 3, 4-COOH 4) were prepared and examined for their photophysical properties, singlet oxygen production, and bioactivity. X-ray studies of 1 and 3·CHCl3 revealed aggregation to give 1D infinite chains. They showed phosphorescent emissions essentially associated with metal-perturbed 3ILCT excited states in 1–3 and mixed 3LL′CT/3ILCT (L = Me2N-pbt, L′ = pic) in 4, in agreement with theoretical calculations. Their tendency to self-assemble was demonstrated in films (1, 3) and DMSO/H2O (3). Complexes 1–3 showed singlet oxygen photosensitization quantum yields (ϕΔ 1O2) in the range of 13–17%. The in vitro biological activity toward selected cell lines in dark conditions and under 5 min irradiation at 450 nm was tested. Complex 3 showed the highest phototoxicity with up to 10 times improvement of the antiproliferative activity upon irradiation, with EC50 values in the nanomolar range, related to overproduction of ROS in dark conditions, further enhanced upon irradiation. Complexes 1–4 did not bind to DNA, while the most potent complex 3 demonstrated interaction with BSA and photooxidation of NADH. Finally, intracellular dose-dependent ROS production in MDA-MB-231 cells treated with 3 was observed in the dark and further stimulated upon blue light irradiation
Integration of lithium-ion battery recycling into manufacturing through digitalization: A perspective
No full textInternational audienceThe lithium-ion batteries (LIBs) industry has expanded quickly despite technological constraints. Additionally, raw materials supply, end-of-life (EoL) management, and the creation of LIB manufacturing policies are receiving attention. All these concerns could be addressed simultaneously by integrating recycling of EoL cells from the early stages of the LIB manufacturing. This article presents perspectives on how to achieve this holistic integration through the means of digitalization. Various challenges of LIB recycling, and different digitalization tools are discussed, shedding light on the latter's potential applications and outcomes. Through the use of the discussed tools to create advanced Digital Twins, it would be possible to screen different recycling processing conditions and materials to achieve higher efficiency, increased safety, at a lower cost. In this regard digitalization of the recycling process for LIB cells, emerges as the key for achieving a collaborative, sustainable, and efficient battery value chain in the European Union. Lastly, in the view of the growing LIB market, this article is thought to be of interest for recycling stakeholders as they move towards a more circular economy model
A computational workflow for the simulation of solid state battery electrodes from manufacturing to electrochemical performance
No full textInternational audienceAll-solid-state lithium ion batteries (ASSBs) have the potential to deliver higher energy and power densities compared to conventional lithium-ion batteries with liquid electrolytes. Due to the use of solid electrolytes, a uniform distribution and close contact between the active material (AM) and solid electrolyte (SE) particles are essential for a proper electrochemical behavior of the electrodes. Thus, understanding the correlation between the microstructure of composite electrodes, charge transport, and cell performance is critical. The composite cathode microstructure composed of Li6PS5Cl and NCM622 obtained from the simulation of its wet manufacturing process is used to implement a 4D (3 spatial coordinates, and time) computational model that simulates the electrochemical behavior during an ASSB cell discharge. The study explores the effect of the conventional calendering technique during manufacturing, demonstrating that the spatial distribution of phases and the presence of residual voids significantly influence percolation, impacting ionic and electronic conduction as well as the electrochemically active surface area. Consequently, these factors dictate the overall performance of the ASSB cell. Our findings highlight the importance of a homogeneous, compact cathode microstructure for achieving optimal ion and electron transport, ultimately enhancing the performance of ASSB cells
Conductive polyaniline hydrogel featuring high toughness and low hysteresis
No full textInternational audiencePolyaniline (PANi) hydrogels show wide applications in artificial skin, flexible robotic, and movement monitor. Nevertheless, limited by the modulus mismatch between rigid PANi and soft hydrogel matrix, high strength and high toughness of PANi hydrogel are mutually exclusive. Although the introduction of sacrificial bonds into hydrogel network can alleviate this contradiction to a certain extent, they always bring about the pronounced energy hysteresis during hydrogel deformations. Inspired by the energy storage and release of macroscopic spring, in this work we propose a molecular entanglement approach for the fabrication of PANi hydrogel featuring high toughness and low hysteresis, where flexible poly(ethylene glycol) (PEG) entangles with chemically cross-linked poly(acrylic acid) (PAA) as hydrogel matrix, while rigid PANi as conductive fillers. The resultant PAA/PEG/PANi hydrogel exhibits high mechanical properties (fracture strength of 0.75 MPa and toughness of 4.81 MJ·m -3 ) and low energy dissipation ratio (28.2% when stretching to 300%). Moreover, PAA/PEG/PANi hydrogel possesses good electrical response to external force, and can be employed as a strain sensor to monitor movements of human joints by producing specific electrical signals. This work provides a straightforward strategy to prepare tough conductive PANi hydrogel with low hysteresis, showing potentials for the elaboration of healthcare devices.</div
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
Coupling of X‐AES Transitions and XPS Photopeaks to Assess the Oxide Formation of Ga and in CuIn 0.7 Ga 0.3 Se 2 Material During Air Aging
No full textInternational audienceABSTRACT The solar absorber Cu (In 0.7 Ga 0.3 )Se 2 (CIGS) undergoes a process of evolution upon exposure to the atmosphere, resulting in the growth of oxide phases. This phenomenon can potentially affect the interfacial properties of CIGS, which in consequence may impact the efficiency of the solar cell. X‐ray photoelectron spectroscopy (XPS) is an appropriate method to analyze the degradation of CIGS upon air aging. However, many photopeaks and Auger lines of the constitutive elements are distributed along the energy scale, and the exact determination of the degradation within the CIGS absorber requires specific care to select peaks to consider to ensure that information arise from similar escape depths. In this study, we propose to investigate the kinetics of degradation of Ga and In at similar depths probed by coupling not only photopeaks but also X‐Auger electron spectroscopy (X‐AES) transitions in the absence of photopeaks in the same energy range. If photopeaks modeling is well established for In and Ga, a decomposition procedure of the X‐AES transitions must be developed. Both linear and nonlinear least square fitting were used and compared, starting to model CIGS, In 2 O 3 , and Ga 2 O 3 references to deploy it after on Auger transitions measured on aged samples. Thanks to the determination of the degradation ratios (oxide phase over CIGS phase) at 3, 7, and 9 nm depth, we show that both In and Ga exhibit similar kinetic of oxide formation, which proceeds gradually by O penetration through the subsurface of the material, this penetration being more and more attenuated deeper