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On-Chip Magnetic Extraction of Circulating Cell-Free DNA from Biological Samples
No full textInternational audienceIn recent years, the analysis of circulating cell-free DNA (cfDNA) containing tumor-derived DNA has emerged as a noninvasive means for cancer monitoring and personalized medicine. However, the isolation of cfDNA from peripheral blood has remained a challenge due to the low abundance and high fragmentation of these molecules. Here, we present a dynamic Magnetic ExTRactiOn (METRO) protocol using microfluidic fluidized bed technology to isolate circulating cfDNA from raw biological materials such as undiluted serum. This protocol maximizes the surface area for DNA binding within the chip in order to capture short DNA fragments. It uses only a few μL of sample and reagents. The protocol can be automated, and it is fully compatible with sensitive DNA amplification methods such as droplet-based digital PCR (ddPCR)
Direct recycling process for production scraps of Li-ion batteries positive electrode based on pressurized CO2
No full textDue to the lack of adapted competitive recycling methods, Lithium-ion Batteries (LIB) production scraps are currently treated as spent batteries, despite their significant difference in characteristics. However, with the drastic increase in LIB production and consequently, the generation of scraps, various innovative recycling techniques have emerged and gained significant attention, aiming to offer greener, cheaper and more direct recycling routes. This study explores a novel solvent-based delamination method that employs a mixture of triethyl phosphate (TEP), acetone, and carbon dioxide (CO2) under pressure and temperature, for the direct recycling of positive electrode production scraps. Optimization of experimental conditions led to achieve a full delamination within 15 minutes at 120°C and 100 bar, with an exceptionally low solvent consumption of 1.5 of TEP to electrode ratio (w/w). The properties of pressurized fluids enhanced the kinetics of delamination while removing the need for stirring and reducing the solvent consumption (by 6.7x), showing a huge advantage compared to other state-of-the-art delamination techniques. Subsequent to the process, the active material LNi0.6Mn0.2Co0.2O2 (NMC622) was easily separated from the current collector, enabling a comprehensive characterization. A more in-depth focus on the electrochemically active material revealed that its chemical composition, crystal structure, and microstructure remained preserved throughout the recycling process. Ultimately, the electrochemical performance of the recycled NMC622 closely resembled that of pristine NMC622, affirming the promising potential of this approach
Identification of degree of ordering in spinel LiNi0.5Mn1.5O4 through NMR and Raman spectroscopies supported by theoretical calculations
No full textInternational audienceThe performance of the high voltage spinel LiNi0.5Mn1.5O4 (LNMO) in Li-ion batteries strongly depends on its synthesis conditions, actual Ni/Mn stoichiometry, and degree of ordering of Ni and Mn. Depending on the extent of this ordering, the spinel structure can be described in the conventional space group Fdm as the non-substituted LiMn2O4 or, for the highly ordered phase, in the space group P4332. As previously reported in the literature, using neutron and electron diffraction, a qualitative description of the extent of ordering can be achieved and roughly related to the electrochemical performance of LNMO. To deeper characterize and understand this complex system, in this paper, we will show that Raman spectroscopy, and especially the characteristics of the band located at 160 cm−1 attributed for the first time to a twisting motion of octahedral entities, allow to estimate the degree of ordering in LNMO, whereas NMR spectroscopy allows to give a clear description of the local environments of Li, in relationship with the Ni/Mn stoichiometry and extent of ordering. Theoretical calculations were used to support the analysis and attribution of the Raman and NMR signals/spectra. These spectroscopic characterizations enabled in-depth insights into the complexity of LNMO in stoichiometry, degree of ordering, and purity versus the presence of rock-salt or layered oxides as defects or crystalline domains
Challenges and perspectives for direct recycling of electrode scraps and end‐of‐life lithium‐ion batteries
No full textInternational audienceThe growing demand and production of lithium‐ion batteries (LIBs) have led to a critical concern regarding their resources and end‐of‐life management. Consequently, LIB recycling has emerged as a prominent topic in academia and in industries, driven by new worldwide governmental regulations and the increasing gap between the supply and demand of critical and strategic raw materials. Widely considered as a more sustainable and cheaper recycling method compared to pyrometallurgy and hydrometallurgy, direct recycling currently grabs the spotlight. This perspective provides insights and outlooks on the chemical and technological challenges of the innovative direct recycling approach for LIBs, addressing both the production scraps and batteries at their end‐of‐life (EOL). Technological advancements, changes in battery chemistry, along with the LIB market dynamics and collaborations between battery makers and recyclers, are key drivers of LIB waste recycling. While production scraps lend themselves well to direct recycling, EOL batteries encounter challenges in adopting this novel recycling technology. Besides, the need to assess novel direct recycling processes using Life Cycle Assessment (LCA) is also important for identifying eco‐design strategies and optimizing the processes, leading to a more sustainable energy storage system
Investigation of the use of foams for silver leaching using the thiosulfate‑copper(II)-ammonia system in the context of e-waste recycling
No full textInternational audienceDue to its physical properties, metallic silver is present in numerous electronic wastes. Its recycling requires selective extraction, which involves leaching of silver as the first step. This work focusses on leaching silver with Cu(II)/NH/SO which has been widely used for gold leaching. As recently shown for the leaching of copper, using foams whose aqueous phase consists of leaching chemicals is a promising way to reduce the environmental footprint, by improving the metal oxidation caused by the fast transfer of O from bubble to bubble. In this work, metallic silver samples are dissolved by foams made of Cu(II)/NH/SO solution with bubbles composed of O-N mixtures. The main problem of the thiosulfate route is its degradation during metal oxidation hence it requires using large quantities of this reactant. The results obtained for our leaching foams show that the quantity of silver leached per quantity of thiosulfate used is about three times greater in comparison with a solution, which would bring a new approach to this problem. Moreover, we investigate the role of the bubble size and the gas composition (dioxygen partial pressure). Besides we find that the dissolved silver is inhomogeneously distributed between the foam column and the bottom solution, with an accumulation of 90 % of silver inside the foam, hence opening an interesting perspective for an easy separation of silver upon leaching. Comparing several surfactants, we show that only non-ionic surfactant polyoxyethylene oleyl ether, Brij O10, shows satisfying results, while dodecyl trimethyl ammonium chloride most likely binds with silver complexes and triggers a quick collapse of the foams
Impedance of nanocapacitors from molecular simulations to understand the dynamics of confined electrolytes
No full textInternational audienceNanoelectrochemical devices have become a promising candidate technology across various applications, including sensing and energy storage, and provide new platforms for studying fundamental properties of electrode/electrolyte interfaces. In this work, we employ constant-potential molecular dynamics simulations to investigate the impedance of gold-aqueous electrolyte nanocapacitors, exploiting a recently introduced fluctuation–dissipation relation. In particular, we relate the frequency-dependent impedance of these nanocapacitors to the complex conductivity of the bulk electrolyte in different regimes, and use this connection to design simple but accurate equivalent circuit models. We show that the electrode/electrolyte interfacial contribution is essentially capacitive and that the electrolyte response is bulk-like even when the interelectrode distance is only a few nanometers, provided that the latter is sufficiently large compared to the Debye screening length. We extensively compare our simulation results with spectroscopy experiments and predictions from analytical theories. In contrast to experiments, direct access in simulations to the ionic and solvent contributions to the polarization allows us to highlight their significant and persistent anticorrelation and to investigate the microscopic origin of the timescales observed in the impedance spectrum. This work opens avenues for the molecular interpretation of impedance measurements, and offers valuable contributions for future developments of accurate coarse-grained representations of confined electrolytes
Collective Long-Lived Zero-Quantum Coherences in Aliphatic Chains
No full textInternational audienceIn nuclear magnetic resonance, long-lived coherences constitute a class of zero-quantum (ZQ) coherences that have lifetimes that can be longer than the relaxation lifetimes T2 of transverse magnetization. So far, such coherences have been observed in systems with two coupled spins with spin quantum numbers I = 1/2, where a term S0T0+T0S0 in the density operator corresponds to a coherent superposition between the singlet S0 and the central triplet T0 state. Here, we report on the excitation and detection of collective long-lived coherences in AA'MM'XX' spin systems in molecules containing a chain of at least three methylene (-CH2-) groups. Several variants of excitation by polychromatic spin-lock induced crossing (poly-SLIC) are introduced that can excite a non-uniform distribution of the amplitudes of terms such as S0S0T0S0S0T0, S0T0S0S0T0S0, and T0S0S0T0S0S0. Once the radio frequency fields are switched off, these are not eigenstates, leading to ZQ precession involving all six protons, a process that can be understood as a propagation of spin order along the chain of CH2 groups before the reconversion into observable magnetization by a second poly-SLIC pulse that can be applied to any one or several of the CH2 groups. In the resulting 2D spectra, the ω2 domain shows SQ spectra with the chemical shifts of the CH2 groups irradiated during the reconversion, while the ω1 dimension shows ZQ signals in absorption mode with linewidths on the order of 0.1 Hz that are not affected by the inhomogeneity of the static magnetic field but can be broadened by chemical exchange as occurs in drug screening. The ZQ frequencies are primarily determined by differences ΔJ between vicinal J-couplings
Energy Resolved Mass Spectrometry for Interoperable Non-resonant Collisional Spectra in Metabolomics
No full textInternational audienceIn untargeted metabolomics, the unambiguous identification of metabolites remains a major challenge. This requires high-quality spectral libraries for reliable metabolite identification, which is essential for translating metabolomics data into meaningful biological information. Several attempts have been made to generate reproducible product ion spectra (PIS) under a low collision energy (E-Lab) regime and nonresonant collisional conditions but have not fully succeeded. We examined the ERMS (energy-resolved mass spectrometry) breakdown curves of two lipo-amino acids and showed the possibility to highlight "singular points", called descriptors hereafter (linked to respective E-Lab depending on the instrument), for each of the monomodal product ion profiles. Using several instruments based on different technologies, the PIS recorded at these specific E-Lab sites shows remarkable similarities. The descriptors appeared as being independent of the fragmentation mechanisms and can be used to overcome the main instrumental effects that limit the interoperability of spectral libraries. This proof-of-concept study, performed on two particular lipo-amino acids, demonstrates the high potential of ERMS-derived information to determine the instrument-specific E-Lab at which PIS recorded in nonresonant conditions become highly similar and instrument-independent, thus comparable across platforms. This innovative but straightforward approach could help remove some of the obstacles to metabolite identification in nontargeted metabolomics, putting an end to a challenging chimera
Elucidating the pivotal role of TSPO in porphyrin-related cellular processes, in Bacillus cereus
No full textInternational audienceA structural homolog of the mammalian TSPO has been identified in the human pathogen Bacillus cereus. BcTSPO, in its recombinant form, has previously been shown to bind and degrade porphyrins. In this study, we generated a ΔtspO mutant strain in B. cereus ATCC 14579 and assessed the impact of the absence of BcTSPO on cellular proteomics and physiological characteristics. The proteomic analysis revealed correlations between the lack of BcTSPO and the observed growth defects, increased oxygen consumption, ATP deficiency, heightened tryptophan catabolism, reduced motility, and impaired biofilm formation in the ΔtspO mutant strain. Our results also suggested that BcTSPO plays a crucial role in regulating intracellular levels of metabolites from the coproporphyrin-dependent branch of the heme biosynthetic pathway. This regulation potentially underlies alterations in the metabolic landscape, emphasizing the pivotal role of BcTSPO in B. cereus aerobic metabolism. Notably, our study unveils, for the first time, the involvement of TSPO in tryptophan metabolism. These findings underscore the multifaceted role of TSPO, not only in metabolic pathways but also potentially in the microorganism's virulence mechanisms
Elucidating Salt Conversion Mechanisms of Lithiated Transition Metal Oxide for Lithium-ion Batteries Recycling
No full textInternational audienceExploring new methods for recycling spent Li-ion batteries is mandatory for facing the ongoing growing demand for strategic elements. Here, we propose a method to chemically convert lithiated transition metal oxides into readily water-soluble sulfate products, preventing the use of highly acidic media typically used in hydrometallurgy. The process comprises a temperature-driven solid-state reaction between the electrode material and potassium hydrogenosulfate molten salt yielding langbeinite K2M2(SO4)3 and potassium/lithium sulfates. The salt conversion of the prototype material LiCoO2 was elucidated, highlighting a complex mechanism. Prior to the melting of the salt, we pointed out an ionic exchange occurring between Li ions and protons from the LiCoO2 and KHSO4 reactants. The accumulation of protons within the layered structure is followed by thermal dehydration, leaving undercoordinated Co ions. Concomitantly, the melting of the salt provides reactive species such as HSO4–, leading to the progressive sulfation of Co ions as revealed by the formation of an intermediate reduced hydroxyl-sulfate phase followed by the final stabilization of K2Co2(SO4)3. Most remarkably, we highlight the compositional versatility of the langbeinite K2M2(SO4)3 by extending this approach to more complex cathode chemistry with nickel and manganese (NMC, NCA), which opens novel insights into versatile recycling methods featuring lower atom consumption