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Highly Porous Hybrid Metal–Organic Nanoparticles Loaded with Gemcitabine Monophosphate: a Multimodal Approach to Improve Chemo‐ and Radiotherapy
Dr. Xue Li Dr. Erika Porcel Dr. Mario Menendez‐Miranda Jingwen Qiu Xiaomin Yang Dr. Christian Serre Alexandra Pastor Dr. Didier Desmaële
ChemMedChem - 15(3) - - 2020
Nanomedicine recently emerged as a novel strategy to improve the performance of radiotherapy. Herein we report the first application of radioenhancers made of nanoscale metal‐organic frameworks (nanoMOFs), loaded with gemcitabine monophosphate (Gem‐MP), a radiosensitizing anticancer drug. Iron trimesate nanoMOFs possess a regular porous structure with oxocentered Fe trimers separated by around 5 Å (trimesate linkers). This porosity is favorable to diffuse the electrons emitted from nanoMOFs due to activation by γ radiation, leading to water radiolysis and generation of hydroxyl radicals which create nanoscale damages in cancer cells. Moreover, nanoMOFs act as “Trojan horses”, carrying their Gem‐MP cargo inside cancer cells to interfere with DNA repair. By displaying different mechanisms of action, both nanoMOFs and incorporated Gem‐MP contribute to improve radiation efficacy. The radiation enhancement factor of Gem‐MP loaded nanoMOFs reaches 1.8, one of the highest values ever reported. These results pave the way toward the design of engineered nanoparticles in which each component plays a role in cancer treatment by radiotherapy.
Methanol and Humidity Capacitive Sensors Based on Thin Films of MOF Nanoparticles
Miguel A. Andrés, Mani Teja Vijjapu, Sandeep G. Surya, Osama Shekhah, Khaled Nabil Salama, Christian Serre, Mohamed Eddaoudi, Olivier Roubeau, and Ignacio Gascón
ACS Publications - 12(3) 4155–4162 - - 2020
The successful development of modern gas sensing technologies requires high sensitivity and selectivity coupled to cost effectiveness, which implies the necessity to miniaturize devices while reducing the amount of sensing material. The appealing alternative of integrating nanoparticles of a porous metal–organic framework (MOF) onto capacitive sensors based on interdigitated electrode (IDE) chips is presented. We report the deposition of MIL-96(Al) MOF thin films via the Langmuir–Blodgett (LB) method on the IDE chips, which allowed the study of their gas/vapor sensing properties. First, sorption studies of several organic vapors like methanol, toluene, chloroform, etc. were conducted on bulk MOF. The sorption data revealed that MIL-96(Al) presents high affinity toward water and methanol. Later on, ordered LB monolayer films of MIL-96(Al) particles of ∼200 nm were successfully deposited onto IDE chips with homogeneous coverage of the surface in comparison to conventional thin film fabrication techniques such as drop-casting. The sensing tests showed that MOF LB films were selective for water and methanol, and short response/recovery times were achieved. Finally, chemical vapor deposition (CVD) of a porous thin film of Parylene C (thickness ∼250–300 nm) was performed on top of the MOF LB films to fabricate a thin selective layer. The sensing results showed an increase in the water selectivity and sensitivity, while those of methanol showed a huge decrease. These results prove the feasibility of the LB technique for the fabrication of ordered MOF thin films onto IDE chips using very small MOF quantities.
Hexane isomers separation on an isoreticular series of microporous Zr carboxylate metal organic frameworks
Adriano Henrique, Tanmoy Maity, Hengli Zhao, de Pedro F. Brântuas, Alírio E. Rodrigues, Farid Nouar, Aziz Ghoufi, Guillaume Maurin, José A. C. Silva and Christian Serre
journal of materials chemistry A - 8 17780-17789 - - 2020
A series of isoreticular Zr carboxylate MOFs, MIL-140A, B and C, exhibiting 1D microporous triangular shaped channels and based on different aromatic dicarboxylate ligands (1,4-BDC, 2,6-NDC and 4,4′-BPDC, respectively), were investigated by chromatographic breakthrough experiments regarding their ability to separate hexane isomers (nC6/2MP/3MP/23DMB/22DMB). Both single and equimolar multicomponent experiments were performed at the temperatures 343, 373, and 423 K and a total hydrocarbon pressure up to 50.0 kPa using the MIL-140B form. The elution order is similar to that of the normal boiling point of the compounds nC6 > 2MP > 3MP > 23DMB > 22DMB. It is noteworthy that this material enables separation of the hexane isomers by class, linear > mono-branched > di-branched, with a selectivity (linear + mono-branched isomers/di-branched isomers) up to 10 at 343 K, decreasing, however, as the temperature increases. Grand canonical Monte Carlo simulations were further performed to gain insight into the adsorption/separation mechanisms, highlighting the crucial need to consider a tiny tilting of the organic linkers for capturing the experimental observations. The impact of the pore size was finally assessed through the comparison with MIL-140A and MIL-140C, respectively, based on multicomponent experiments at 343 K. We evidenced a significant decrease of the selectivity (about 2) in both cases while the loadings were decreased or increased for MIL-140A and MIL-140C, respectively. Additionally, MIL-140C was demonstrated to exhibit an uncommon shift in the elution order occurring between nC6 and 3MP, 3MP being the last compound to saturate in the column.
First Example of Protonation of Ruddlesden–Popper Sr 2 IrO 4 : A Route to Enhanced Water Oxidation Catalysts
Ronghuang Zhang, Paul E. Pearce, Vanessa Pimenta, Jordi Cabana, Heifang Li, Daniel Alves Dalla Corte, Artem M. Abakumov, Gwenaëlle Rousse, Domitille Giaume, Michael Deschamps, and Alexis Grimaud
Chemistry of Materials, American Chemical Society - 32 (8) 3499-3509 - - 2020
Water electrolysis is considered to be a promising way to store and convert excess renewable energies into hydrogen, which is of high value for many chemical transformation processes such as the Haber-Bosch process. The main challenge to promote the deployment of the polymer electrolyte membrane water electrolysis (PEMWE) technology lies in the design of robust catalysts for the oxygen evolution reaction (OER) under acidic conditions, since most of the transition metal-based oxides undergo structural degradation under these harsh acidic conditions. To broaden the variety of candidate materials as OER catalysts, a cation-exchange synthetic route was recently explored to reach crystalline pronated iridates with unique structural properties and stability. In this work, a new protonated phase H3.6IrO4·3.7H2O, prepared via Sr2+/H+ cation exchange at room temperature starting from the parent Ruddlesden–Popper Sr2IrO4 phase, is described. This is the first discovery of crystalline protonated iridate forming from a perovskite-like phase, adopting a layered structure with apex-linked IrO6 octahedra. Furthermore, H3.6IrO4·3.7H2O is found to possess not only an enhanced specific catalytic activity, superior to that of other perovskite-based iridates, but also a mass activity comparable to that of nanosized IrOx particles, while showing an improved catalytic stability owing to its ability to reversibly exchange protons in acid.
Revealing the Impact of Electrolyte Composition for Co-Based Water Oxidation Catalysts by the Study of Reaction Kinetics Parameters
Yan Duan, Nicolas Dubouis, Jiaqiang Huang, Daniel Alves Dalla Corte, Vanessa Pimenta, Zhichuan J. Xu, and Alexis Grimaud
ACS Publications - 7 4160–4170 - - 2020
Recent studies have revealed the critical role played by the electrolyte composition on the oxygen evolution reaction (OER) kinetics on the surface of highly active catalysts. While numerous works were devoted to understand the effect of the electrolyte composition on the physical properties of the catalysts’ surface, very little is known yet about its exact impact on the OER kinetics parameters. In this work, we reveal that the origin for the electrolyte-dependent OER activity for Co-based catalysts originates from two different effects. Increasing the alkaline electrolyte concentration for La1–xSrxCoO3−δ perovskites with x > 0 and for amorphous CoOOH increases the pre-exponential factor, which can be explained either by an increase of the concentration of active sites or by a change in the entropy of activation. However, changing the alkali cation results in a decrease of the apparent activation enthalpy for Fe-containing amorphous films, traducing a change in intermediates’ binding energies.
Machine Learning to Improve the Sensing of Biomolecules by Conical Track-Etched Nanopore
Nathan Meyer, Jean-Marc Janot , Mathilde Lepoitevin , Michaël Smietana ,Jean-Jacques Vasseur ,Joan Torrent and Sébastien Balme
Biosensors - 10(10) 140 - - 2020
Single nanopore is a powerful platform to detect, discriminate and identify biomacromolecules. Among the different devices, the conical nanopores obtained by the track-etched technique on a polymer film are stable and easy to functionalize. However, these advantages are hampered by their high aspect ratio that avoids the discrimination of similar samples. Using machine learning, we demonstrate an improved resolution so that it can identify short single- and double-stranded DNA (10- and 40-mers). We have characterized each current blockade event by the relative intensity, dwell time, surface area and both the right and left slope. We show an overlap of the relative current blockade amplitudes and dwell time distributions that prevents their identification. We define the different parameters that characterize the events as features and the type of DNA sample as the target. By applying support-vector machines to discriminate each sample, we show accuracy between 50% and 72% by using two features that distinctly classify the data points. Finally, we achieved an increased accuracy (up to 82%) when five features were implemented.
Liquid-liquid coffee-ring effect.
Vincent Poulichet,Mathieu Morel,Sergii Rudiuk,Damien Baigl
Journal of Colloid and Interface Science - - DOI: 10.1016/j.jcis.2020.03.094 - 2020
The so-called coffee-ring effect (CRE) is extraordinarily common, problematic in industry and attractively puzzling for researchers, with the accepted rule that it requires two key-ingredients: solvent evaporation and contact line pinning. Here, we demonstrate that the CRE also occurs when the solvent of a pinned sessile drop transfers into another liquid, without involving any evaporation. We show that it shares all characteristic features of the evaporative CRE: solvent transfer-driven transport of solutes to the contact line, ring-shaped deposit, closely-packed particle organization at the contact line, and size-dependent particle sorting. We thus suggest expanding the definition of the coffee-ring effect to any pinned drop having its solvent transferring to an outer medium where the drop compounds cannot be dissolved.
Self-Propelled Water Drops on Bare Glass Substrates in Air: Fast, Controllable, and Easy Transport Powered by Surfactants
Pauline E. Galy, Sergii Rudiuk, Mathieu Morel, and Damien Baigl
Langmuir - 36, 25 6916–6923 - doi : 10.1021/acs.langmuir.9b03727 - 2020
Self-propelled drops are capable of motion without external intervention. As such, they constitute attractive entities for fundamental investigations in active soft matter, hydrodynamics, and surface sciences, as well as promising systems for autonomous microfluidic operations. In contrast with most of the examples relying on organic drops or specifically treated substrates, here we describe the first system of nonreactive water drops in air that can propel themselves on a commercially available ordinary glass substrate that was used as received. This is achieved by exploiting the dynamic adsorption behavior of common n-alkyltrimethylammonium bromide (CnTAB) surfactants added to the drop. We precisely analyze the drop motion for a broad series of surfactants carrying n = 6 to 18 carbon atoms in their tail and establish how the motion characteristics (speed, probability of motion) are tuned by both the hydrophobicity and the concentration of the surfactant. We show that motion occurs regardless of the n value but only in a specific concentration range with a maximum speed at around one tenth of the critical micelle concentration (CMC/10) for most of the tested surfactants. Surfactants of intermediate hydrophobicity are shown to be the best candidates to power drops that can move at a high speed (1–10 cm s–1), the optimal performance being reached with [C12TAB] = 800 μM. We propose a mechanism where the motion originates from the anisotropic wettability of the substrate created by the electrostatic adsorption of surfactants beneath the moving drop. Simply drawing lines with a marker pen allows us to create guiding paths for drop motion and to achieve operations such as complex trajectory control, programmed drop fusion, drop refilling, as well as drop moving vertically against gravity. This work revisits the role of surfactants in dynamic wetting and self-propelled motion as well as brings an original strategy to build the future of microfluidics with lower-cost, simpler, and more autonomous portable devices that could be made available to everyone and everywhere.

From bulk crystallization of inorganic nanoparticles at the air/water interface: tunable organization and intense structural colors
Jacopo Vialetto,Sergii Rudiuk,Mathieu Morel,Damien Baigl
Nanoscale - 36, 25 6916–6923 - DOI: 10.1039/c9nr10965j - 2020
The "flipping method" is a new straightforward way to both adsorb and organize microparticles at a liquid interface, with ultralow amounts of a surfactant and no other external forces than gravity. Here we demonstrate that it allows the adsorption of a variety of inorganic nanoparticles at an air/water interface, in an organized way, which is directly controlled by the surfactant concentration, ranging from amorphous to highly crystalline two-dimensional assemblies. With micromolar amounts of a conventional cationic surfactant (dodecyltrimethylammonium bromide, DTAB), nanoparticles of different compositions (silica, silver, and gold), sizes (down to 100 nm) and shapes (spheres and cubes) adsorb from the bulk and directly organize at the air/water interface, resulting in marked optical properties such as reflectivity or intense structural coloration.

An Epigenetic Priming Mechanism Mediated by Nutrient Sensing Regulates Transcriptional Output
Natalia Stec, Katja Doerfel, Kelly Hills-Muckey, Victoria M. Ettorre, Sevinc Ercan, Wolfgang Keil, C. M. Hammell
bioRxiv - - - 2020
While precise tuning of gene expression levels is critical for most developmental pathways, the mechanisms by which the transcriptional output of dosage-sensitive molecules is established or modulated by the environment remain poorly understood. Here, we provide a mechanistic framework for how the conserved transcription factor BLMP-1/Blimp1 operates as a pioneer factor to decompact chromatin near its target loci hours before transcriptional activation and by doing so, regulates both the duration and amplitude of subsequent target gene transcription. This priming mechanism is genetically separable from the mechanisms that establish the timing of transcriptional induction and functions to canalize aspects of cell-fate specification, animal size regulation, and molting. A key feature of the BLMP-1-dependent transcriptional priming mechanism is that chromatin decompaction is initially established during embryogenesis and maintained throughout larval development by nutrient sensing. This anticipatory mechanism integrates transcriptional output with environmental conditions and is essential for resuming normal temporal patterning after animals exit nutrient-mediated developmental arrests.


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579 publications.