HAL Portal ESPCI (Ecole Supérieure de Physique et de Chimie Industrielles)
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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
High throughput measurement of bubble coalescence times using digital millifluidics
No full textInternational audienceFoams may form in oil mixtures, such as lubricants, as a result of air entrainment. The long lifetimes of those foams significantly impair the thermal properties of lubricants and increase power losses by engines (Zhan et al., 2022). In order to improve the efficiency of lubricants, we offer here to gain insights in the stability of bubbles in binary mixtures of miscible oils as a function of bubble size and liquid composition. To do so, using a micro-millifluidic set-up, we control the formation of bubbles in oil mixtures and study variations in their coalescence time. The set-up allows to easily vary the curvature of the bubbles over one decade, perform statistics over a large number of coalescence events and measure coalescence times that span more than three orders of magnitude
Electronic structure origins of radical character in triangular fused acenes: sextet stabilization vs. antiaromaticity release
No full textInternational audienceTriangular acenes display size-dependent radical character arising from the interplay between Clar's sextet stabilization and the release of cyclobutadiene antiaromaticity
Tailored hybridization of MIL-101(Cr) with graphene oxide enables enhanced hydrogen storage and delivery
No full textInternational audienceThe development of practical hydrogen (H2) storage solutions is essential for a net-zero, secure, and affordable energy future. This study explores the effect of the hybridization method on the H2 storage and delivery performance of nanoporous MIL-101(Cr)@GO materials, composed of micro–mesoporous Cr terephthalate MIL-101(Cr) and graphene oxide (GO). MIL-101(Cr) was chosen for its high surface area, open metal sites and stability, while GO was selected for its higher density and potential to enhance H2 storage when combined with MIL-101(Cr). Three hybridization approaches were employed: one in situ method and two ex situ methods, namely post-synthetic modification and physical blending using resonant acoustic mixing (RAM). The impact of these methods on the structural, textural and adsorption properties of the hybrids was systematically analyzed. GO incorporation consistently reduced the surface area of all hybrids but promoted ultramicroporosity (pore width <0.7 nm). Ex situ hybrids retained textural features closer to the pristine MOF and exhibited higher gravimetric H2 uptake than pure MIL-101(Cr) and the in situ hybrid. Notably, they achieved up to 22% higher excess H2 uptake (wt%) at 273 K and 100 bar compared to bare MIL-101(Cr). On the other hand, the in situ hybrid, despite a lower gravimetric capacity, demonstrated a threefold increase in tapped density, resulting in a 6–7% improvement in volumetric H2 performance: total stored and deliverable. These findings highlight the critical role of synthesis strategy in tailoring hybrid material properties to optimize H2 storage and delivery under varying conditions
Marine Model Organisms for Mechanobiology Studies
No full textInternational audienceMarine invertebrate species have been used as model organisms in evo-devo studies for over a century. These species provided a great advantage in seminal microscopic studies because of the large size of their eggs and embryos and the easy accessibility to the first embryological processes afforded by their external fertilization and development. This review provides a historical perspective on the use of marine invertebrates—including echinoderms, ascidians, and spiralians—in the study of embryo mechanics. Here, we highlight the key contributions of marine invertebrates to the understanding of cortical and cytoplasmic mechanics, the implementation of early cleavage patterns, and tissue mechanics. We also examine the emergence of different blastula shapes in metazoans and focus on the clear dichotomy between compact and hollow embryos, suggesting a canalization of a compact embryo shape in taxa that display invariant cleavage patterns such as nematodes, spiralians, and ascidians.With recent advances in high-resolution imaging, computational modeling, and the development of modern genetic and genomic tools, marine invertebrate model organisms continue to be at the forefront of evolutionary developmental biology and mechanobiology. Their contribution to these fields not only provides invaluable insights into the fundamental principles of morphogenesis but also offers an ideal comparative framework that allows the exploration of the evolution of mechanical and biological processes across metazoans
Tailoring trap depth distributions in ZnGa2O4: Cr3+ nanoparticles for optimized persistent luminescence across various functional temperature ranges
No full textInternational audiencePersistent phosphors have attracted significant attention for their potential application in safety signage, road markings, data storage, anti-counterfeiting technologies, and biomedical fields. However, despite the significant advancements in room-temperature persistent phosphors and deep-trap materials for information storage, development of low-temperature persistent phosphors with strong afterglow emission remains a considerable challenge. In this study, we successfully modified the trap depth distribution in ZnGa2O4: Cr3+ nanoparticles (ZGO:Cr NPs) by carefully controlling the synthesis conditions in order to develop nanoscale persistent phosphors tailored for various temperature-dependent applications. ZnGa2O4: Cr3+ nanoparticles were synthesized via a rapid, facile, and environmentally friendly microwave-assisted hydrothermal method. A subsequent thermal treatment at temperatures of 500 and 700 ◦C was employed to further modify their structure and, consequently, their optical properties. Notably, the ZGO:Cr NPs without any subsequent calcination (ZGO MW) exhibit strong and long-lasting luminescence at cryogenic temperatures (15–200 K) and they show great potential for applications requiring continuous cooling at liquid nitrogen temperatures, such as the cryopreservation of biological agents, viruses, and tissues. In contrast, ZGO:Cr NPs calcined at 700 ◦C (ZGO 700) demonstrate stabili-zation of deeper traps, with activation energies near room temperature, which shows promise for conventional persistent luminescence applications requiring small particle sizes (<10 nm). Meanwhile, ZGO:Cr NPs calcined at 500 ◦C (ZGO 500) display a broad distribution of traps and a remarkably wide operational range (15–400 K), dueto the coexistence of multiple Cr3+ environments, making it highly suitable for applications requiring stable persistent luminescence behaviour at very wide range of temperatures
White light interferometry analysis for measuring thin film thickness down to a few nanometers
No full textInternational audienceAbstract We present a practical white-light interferometric method, supported by an open-source Python library optifik for automated spectrum-to-thickness deduction, enabling foam film measurements down to a few nanometers. We describe three typical spectral scenarii encountered in this method: spectra exhibiting numerous interference fringes, spectra with a moderate number of peaks, and spectra with only a few identifiable features, providing illustrative examples for each case. We also discuss the main limitations of the technique, including spectral range constraints, the necessity of knowing the refractive index, and the influence of spectral resolution and signal quality. Finally, we demonstrate the application of the method in a time-resolved study of a TTAB (tetradecyltrimethylammonium bromide) foam film undergoing elongation and thinning. This method can be adapted to measure any thin non-opaque layer. Graphic Abstract
Tissue stress measurements with Bayesian Inversion Stress Microscopy
No full textCells within biological tissue are constantly subjected to dynamic mechanical forces. Measuring the internal stress of tissues has proven crucial for our understanding of the role of mechanical forces in fundamental biological processes like morphogenesis, collective migration, cell division or cell elimination and death. Previously, we have introduced Bayesian Inversion Stress Microscopy (BISM), which is relying on measuring cell-generated traction forces in vitro and has proven particularly useful to measure absolute stresses in confined cell monolayers. We further demonstrate the applicability and robustness of BISM across various experimental settings with different boundary conditions, ranging from confined tissues of arbitrary shape to monolayers composed of different cell types. Importantly, BISM does not require assumptions on cell rheology. Therefore, it36 pages, 12 figure
Modal Homogenization of High-Contrast Mie Metasurfaces: From Symmetry Control to Fano, ATS, and Bianisotropic Responses
No full textWe develop an asymptotic homogenization theory for high-permittivity Mie-resonant metasurfacesilluminated in transverse-electric (TE) polarization. In the subwavelength resonant regime, themetasurface is replaced by an effective interface equipped with frequency-dependent transmissionconditions involving three surface susceptibilities (γee, γmm, γem) that fully govern reflection andtransmission. A central ingredient is a so-called Static–Dynamic Cell Eigenproblem (SD-Cell EP)posed on the unit cell, coupling a dynamic Helmholtz equation inside the inclusion to a static Laplaceequation outside. Its real eigenvalues and eigenmodes yield a modal decomposition of the effectiveparameters, each resonance contributing as a simple pole. This structure naturally leads to reduceddescriptions (single-mode Lorentz, weakly coupled two-mode Fano, and strongly coupled Autler–Townes-type models) that retain physical transparency while remaining quantitatively accurate. Forsymmetric (rectangular) inclusions, the theory recovers purely electric or magnetic resonances andtheir transition from Lorentzian to Fano and Autler–Townes behavior. For asymmetric (triangular)inclusions, symmetry breaking activates electromagnetic coupling and turns the metasurface into areciprocal bianisotropic reflector, enabling strongly asymmetric scattering and, in the presence ofweak loss, nearly perfect one-sided absorption
Synergistic Dual-Halide Anion Engineering for Efficient Interface Passivation in 1.68 eV Wide-Bandgap Perovskite Solar Cells for Indoor Photovoltaics
No full textInternational audienceWide-bandgap (1.68 eV) perovskite solar cells (PSCs) are considered promising candidates for indoor photovoltaics due to their favorable optical properties. However, their power conversion efficiency (PCE) is significantly constrained by large open-circuit voltage (V OC ) losses, which primarily originate from intrinsic halide vacancy defects and uncoordinated Pb 2+ located at the surface and grain boundaries of the perovskite films. Additionally, the energy level mismatches at the perovskite/electron transport layer (ETL) interface further aggravate V OC losses by promoting non-radiative recombination. Herein, we report a synergistic dual-halide interface passivation strategy based on methylammonium iodide (MAI) and methylammonium chloride (MACl), in which the two halides play complementary and mechanistically distinct roles. MAI effectively reacts with and converts residual surface PbI 2 into the perovskite phase, while simultaneously passivating iodine-related vacancy defects. In parallel, MACl induces beneficial chloride incorporation at the 3 interface, enabling slight bandgap broadening and producing a favorable vacuum-level shift that optimizes energy-level alignment between the perovskite and electron transport layer. When applied together, MAI and MACl deliver a cooperative passivation effect, substantially suppressing non-radiative recombination, prolonging carrier lifetimes, and facilitating more efficient charge extraction. As a result, the optimized 1.68 eV PSCs achieve a notable PCE of 20.41% with a V OC of 1.262 V under standard AM 1.5G illumination, surpassing the untreated counterparts that achieve 18.48% with a V OC of 1.169 V. More importantly, under indoor lighting conditions, the modified PSCs exhibit outstanding performance, delivering PCEs of 36.74% and 32.36% under 1000 lux and 200 lux LED illumination, respectively, demonstrating their strong potential for indoor photovoltaics