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Phototoxicity of Hydroxymethyl-BODIPYs: Are Photocages That Innocent?
No full textInternational audiencePhotocages are photosensitive molecules that can release specific compounds, usually of biological relevance (e.g., drugs, cellular messengers, etc.), under light irradiation. Along with these compounds, the photocages themselves are putative release byproducts. The (photo-)cytotoxicity of them is hardly known and scarcely studied. To explore these compounds, we synthesized the known BODIPY derivatives commonly used as photocages, i.e., WinterGreen and WinterRed. We investigated in depth their photophysical properties in organic solvents and phosphate buffer. The formation of aggregates by the compounds was analyzed by dynamic light scattering (DLS) and spectral methods, which demonstrated their J-aggregate nature. All compounds exhibited significant phototoxicity in biological assays upon light irradiation at two wavelengths (510 and 645 nm), corresponding to their absorption maxima, in both cancerous (A549) and non-cancerous (RPE-1) cell lines. Investigations into the reactive oxygen species (ROS) generation in organic solutions and intracellularly suggested that the observed phototoxicity arises via a Type I photodynamic therapy (PDT) mechanism. These findings highlight the need for greater scrutiny of photocages themselves in biological studies. Far from being inert carriers, they may exert substantial biological effects, and in some cases, their activity could even surpass that of the released therapeutic agent
3-TMA PROXYL: A high-potential, highly soluble nitroxide for enhanced stability and performance in aqueous organic redox flow batteries
No full textInternational audienceIn response to the growing demand for sustainable and efficient stationary energy storage solutions, this study introduces and evaluates a novel posolyte, 3-TMA PROXYL, tailored for aqueous organic redox flow battery (AORFB) applications. Easily synthesized at the gram scale, 3-TMA PROXYL presents an unprecedented combination of high redox potential (1.06 V vs SHE) and remarkable solubility (> 3 M in 1 M NaCl), resulting in an increased theoretical capacity of 80 Ah L⁻¹. Paired with methyl viologen as a negolyte, the 3-TMA PROXYL battery achieves an 8 % improvement in cell voltage (1.45 V) surpassing the benchmark 4-TMA TEMPO in energy and power density and competing with it regarding stability. Detailed 1 H NMR and UV-visible spectroscopy analyses indicate that 3-TMA PROXYL undergoes minimal irreversible chemical degradation, with observed capacity fade attributed primarily to self-discharge. These results establish 3-TMA PROXYL as a reliable alternative to state-of-the-art nitroxides, paving the way for five-membered ring nitroxides in high-performance, sustainable redox flow applications.</div
Pseudo-4-component photoredox-catalyzed alkylative amidination/carbamoylation of styrenes with isocyanides and redox-active esters
No full textInternational audienceWe report a photoredox-catalyzed pseudo-four-component process for the alkylative amidination of styrenes using isocyanides and redox-active esters (RAEs). This redox-neutral radical-polar crossover reaction shows broad functional group tolerance. The RAE serves as both a radical and nucleophile source, with the initially released phthalimide anion reintegrated into the final product. The resulting amidines can be readily derivatized into amides, tetrazoles, nitriles, or aldehydes, enhancing the synthetic utility of this approach
Noise2Noise Image Reconstruction of Lifetime Maps in Halide Perovskite Thin Films
No full textInternational audienceWe present an unsupervised deep-learning approach for lifetime map reconstruction from noisy time-resolved fluorescence imaging (TR-FLIM) datasets. In the context of semiconductor and photovoltaic device characterisation, this method is critical for accurately predicting solar cell performance and detecting early signs of degradation. More precisely, we consider an unsupervised Noise2Noise (N2N) training framework combined with physics-driven modelling for the quantitative reconstruction of lifetime maps. The proposed approach incorporates a log-linear fit in the N2N loss function and parameterises the unknown maps as outputs of a shallow neural network with a multibranch architecture. By learning from multiple noisy acquisitions of the same scene, our method effectively allows an accurate estimation with shorter acquisition protocols, which translates into a lower risk of damage for the sample under consideration. Tests on simulated data and comparisons with available model-based approaches show that the proposed approach improves robustness w.r.t. noise levels with limited tuning of the regularisation/algorithmic parameters
Homoepitaxial growth of device-grade GaAs using low-pressure remote plasma CVD
No full textInternational audienc
Physics-Assisted Machine Learning for the Simulation of the Slurry Drying in the Manufacturing Process of Battery Electrodes: A Hybrid Time-Dependent VGG16-DEM Model
No full textInternational audienceIn this study, we present a hybrid Physics-Assisted Machine Learning (PAML) model that integrates Deep Learning (DL) techniques with the classical Discrete Element Method (DEM) to simulate slurry drying during a lithium-ion battery electrode manufacturing process. This model predicts the microstructure evolution leading to the formation of the electrode as a time-series along the drying process. The hybrid approach consists in performing a certain amount of DEM simulation steps, nDEM, after every DL prediction, mitigating the risk of unphysical predictions, like overlapping particles. Our PAML model was rigorously tested by evaluating different functional metrics of the predicted electrodes, including density, porosity, tortuosity factor, and radial distribution function. We conducted an in-depth analysis of performance versus accuracy, particularly focusing on the impact of the nDEM hyperparameter, which represents the number of DEM steps executed between two subsequent DL predictions. Despite the model being trained on a specific formulation (96% of Active Material, AM, and 4% of Carbon Binder Domain, CBD), it demonstrated exceptional generalization capability when used to extrapolate to a different formulation (94% AM and 6% CBD). This adaptability highlights the robustness of our PAML hybrid approach. Furthermore, the integration of DL significantly reduced the computational cost versus the original DEM model simulation, decreasing the calculation time from 615 to 36 min for the whole slurry drying simulation process. Our findings underscore the potential of combining ML with traditional simulation methods to enhance efficiency and accuracy in the field of electrode manufacturin
Quadrupolar NMR relaxation as a local probe of collective dynamics in aqueous alkaline and alkaline-earth chloride solutions
No full textInternational audienceWhile nuclear magnetic resonance (NMR) provides valuable insights into the local environment of many nuclei, the unambiguous interpretation of the signal in terms of microscopic dynamics is often difficult, particularly when the quadrupolar relaxation mechanism comes into play. Here, we investigate the quadrupolar NMR relaxation of cations and anions in aqueous alkaline and alkaline-earth chloride solutions across a broad range of salt concentrations. Using a combination of density functional theory calculations and classical molecular dynamics simulations, we compute the electric field gradient (EFG) fluctuations over the relevant time scales. Predicted NMR relaxation rates are in good agreement with experiments from the literature. As previously reported for NaCl, we find that the increase in relaxation rate with salt concentration is primarily driven by the slowing of EFG fluctuations, while changes in the static variance of the EFG play a minor role. We highlight some specific features for smaller and divalent cations compared to the other monovalent ones. In addition, we assess the relevance of the Stokes–Einstein–Debye model, frequently used to analyze NMR relaxation experiments, for these aqueous electrolytes and highlight the link between the collective dynamics of the liquid underlying the EFG fluctuations at the ion positions and the stress fluctuations. Our results generalize observations for Na+ in aqueous NaCl solutions, showing that models assuming a viscous model of the solvent dynamics are insufficient to describe EFG fluctuations in these systems and illustrate the relevance of molecular simulations to interpret NMR relaxation experiments in terms of microscopic dynamics
Shipping Noise Impact on Blue Mussel
No full textInternational audienceThe global anthropogenic oceanic noise due to shipping is predicted to double every 11.5 years, putting marine organisms at risk. While the impact of noise on marine mammals is well documented, its effect on molluscs, which hold immense economic and ecological importance, remain largely unknown. To investigate the consequences of noise on mollusc metabolism during crucial early life stages, blue mussel larvae were exposed to shipping noise in a laboratory setting until the post-larval stage and their metabolome was analysed. Multivariate analyses of the metabolome showed that shipping noise induces stress-related inflammation with increased energy demand, higher protein turnover, and disrupted nervous system activity. Consequently, noise promoted a delayed metamorphosis in suboptimal habitats with greater metabolic costs, which may impact ecosystem and aquaculture sustainability as competent mussel larvae struggle to select suitable development habitats. Without action to limit underwater noise, such impacts could disrupt population structures and marine biodiversit
Synthesis, Characterization, and Biological Evaluation of Red Light‐Activatable BODIPY‐Caged Ceritinib Compounds
No full textInternational audienceIn this work, we aimed at photocaging the well‐known anticancer agents dasatinib, ceritinib, gemcitabine, and combretastatin A4 with red‐light activatable 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY)‐based cages using a carbonate/carbamate linking strategy. Due to the synthetic challenges discussed in this article, we only obtained two target compounds, namely two caged ceritinib compounds. The latter were characterized in‐depth by nuclear magnetic resonance spectroscopy (NMR, 1H, COSY, 13C), high‐resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and their purity was evaluated by elemental analysis. Their photophysical characteristics were also measured including absorption and emission spectra, quantum yields, and lifetimes. Analysis of the products after irradiation of the compounds allowed us to make assumptions about the possible mechanism of the phototransformations. Moreover, we conducted biological studies to determine the phototoxicity indexes of A549 cancer cells. While the two compounds were found to be non‐toxic, the BODIPY precursors themselves were found to be highly toxic upon irradiation with phototoxicity indexes up to 1400