Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Énergie

Since the papyri, cellulose has played a significant role in human culture, especially as paper. Nowadays, this ancient product has found new scientific applications in the expanding sector of paper-based technology. Among paper-based devices, paper-based biosensors raise a special interest. The high selectivity of biomolecules for target analytes makes these sensors efficient. Moreover, simple paper-based detection devices do not require hardware or specific technical skill. They are inexpensive, rapid, user-friendly and therefore highly promising for providing resource-limited settings with point-of-care diagnostics. The immobilization of biomolecules onto cellulose is a key step in the development of these sensing devices. Following an overview of cellulose structural features and physicochemical properties, this article reviews current techniques for the immobilization of biomolecules on paper membranes. These procedures are categorized into physical, biological and chemical approaches. There is no universal method for biomolecule immobilization. Thus, for a given paper-based biochip, each strategy can be considered.

The development of innovative techniques for the functionalization of carbon nanotubes that preserve their exceptional quality, while robustly enriching their properties, is a central issue for their integration in applications. In this work, we describe the formation of a covalent network of porphyrins around MWNT surfaces. The approach is based on the adsorption of cobalt(II) meso-tetraethynylporphyrins on the nanotube sidewalls followed by the dimerization of the triple bonds via Hay-coupling; during the reaction, the nanotube acts as a template for the formation of the polymeric layer. The material shows an increased stability resulting from the cooperative effect of the multiple π-stacking interactions between the porphyrins and the nanotube and by the covalent links between the porphyrins. The nanotube hybrids were fully characterized and tested as the supported catalyst for the oxygen reduction reaction (ORR) in a series of electrochemical measurements under acidic conditions. Compared to similar systems in which monomeric porphyrins are simply physisorbed, MWNT-CoP hybrids showed a higher ORR activity associated with a number of exchanged electrons close to four, corresponding to the complete reduction of oxygen into water.

Carbon nanotubes (CNTs) are a central part of advanced nanomaterials and are used in state-of-the-art technologies, based on their high tensile strength, excellent thermal transfer properties, low-band gaps and optimal chemical and physical stability. Carbon nanotubes are also intriguing given their unique -electron-rich structures, which opens a variety of possibilities for modifications and alterations of their chemical and electronic properties. In this review, a comprehensive survey of the methods of solubilization of carbon nanotubes is presented, forming the methodological foundation for synthesis and manufacturing of modified nanomaterials. The methods presented herein show that solubilized carbon nanotubes have a great potential in being applied as reactants and components for advanced solar cell technologies, nanochemical compounds in electronics and as parts in thermal transfer management. An example lies in the preservation of the aromatic chemistry in CNTs and ligation of functional groups to their surfaces, which confers CNTs with an optimal potential as tunable Schottky contacts, or as parts in nanotransistors and nano-resistances. Future nanoelectronic circuits and structures can therefore depend more and more on how carbon nanotubes are modified and functionalized, and for this, solubilization is often a critical part of their fabrication process. This review is important, is in conjecture with the latest developments in synthesis and modification of CNTs, and provides the know-how for developing new CNT-based state-of-the-art technologies, particularly with emphasis on computing, catalysis, environmental remediation as well as microelectronics.

Abstract Raman spectra were acquired on a series of natural and synthetic sulfide minerals, commonly found in enstatite meteorites: oldhamite (CaS), niningerite or keilite ((Mg,Fe)S), alabandite (MnS), troilite (FeS), and daubreelite (Cr 2 FeS 4 ). Natural samples come from three enstatite chondrites, three aubrites, and one anomalous ungrouped enstatite meteorite. Synthetic samples range from pure endmembers (CaS, FeS, MgS) to complex solid solutions (Fe, Mg, Ca)S. The main Raman peaks are localized at 225, 285, 360, and 470 cm −1 for the Mg‐rich sulfides; at 185, 205, and 285 cm −1 for the Ca‐rich sulfides; at 250, 370, and 580 cm −1 for the Mn‐rich sulfides; at 255, 290, and 365 cm −1 for the Cr‐rich sulfides; and at 290 and 335 cm −1 for troilite with, occasionally, an extra peak at 240 cm −1 . A peak at 160 cm −1 is present in all Raman spectra and cannot be used to discriminate between the different sulfide compositions. According to group theory, none of the cubic monosulfides oldhamite, niningerite, or alabandite should present first‐order Raman spectra because of their ideal rocksalt structure. The occurrence of broad Raman peaks is tentatively explained by local breaking of symmetry rules. Measurements compare well with the infrared frequencies calculated from first‐principles calculations. Raman spectra arise from activation of certain vibrational modes due to clustering in the solid solutions or to coupling with electronic transitions in semiconductor sulfides.

Palladium nanoparticles were immobilized on multi-walled carbon nanotubes by a layer-by-layer approach, resulting in a well-defined assembly that was used as a heterogenous catalyst in Suzuki couplings.

New developments in nanosciences and nanotechnologies are strongly dependent on our ability to synthesize well-controlled nanobuilding units, with specific properties. We report in this paper the first synthesis of hybrid single-walled imogolite nanotubes (OH)3Al2O3SixGe1–xCH3 with diameter-controlled hydrophobic nanopores varying from 1.8 to 2.4 nm. Methylation and nanotube dimensions are studied by combining infrared spectroscopy, cryo-TEM observations, and X-ray scattering measurements. We show that, in solution, the water density inside methylated nanotubes is decreased by a factor of 3 compared to the bulk value. Spontaneous confinement of bromopropanol molecules inside the nanotubes, when added to the solution, is demonstrated. These newly synthesized nanotubes may open up possibilities for water filtration or water decontamination.

We describe the synthesis and the physical properties of polyaromatic hydrocarbons (PAHs) containing a phosphorus atom at the edge. In particular, the impact of the successive addition of aromatic rings on the electronic properties was investigated by experimental (UV/Vis absorption, fluorescence, cyclic voltammetry) and theoretical studies (DFT). The physical properties recorded in solution and in the solid state showed that the P-containing PAHs exhibit properties expected for an emitter in white organic light-emitting diodes (WOLEDs).

Organic semiconductors have great potential for producing hydrogen in a durable and economically viable manner because they rely on readily available materials and can be solution-processed over large areas. With the objective of building efficient hybrid organic-inorganic photoelectrochemical cells, we combined a noble-metal-free and solution-processable catalyst for proton reduction, MoS3, and a poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction (BHJ). Different interfacial layers were investigated to improve the charge transfer between P3HT:PCBM and MoS3. Metallic Al/Ti interfacial layers led to an increase of the photocurrent by up to 8 mA cm(-2) at reversible hydrogen electrode (RHE) potential with a 0.6 V anodic shift of the H2 evolution reaction onset potential, a value close to the open-circuit potential of the P3HT:PCBM solar cell. A 50-nm-thick C60 layer also works as an interfacial layer, with a current density reaching 1 mA cm(-2) at the RHE potential. Moreover, two recently highlighted1 figures-of-merit, measuring the ratio of power saved, Φsaved,ideal and Φsaved,NPAC, were evaluated and discussed to compare the performances of various photocathodes assessed in a three-electrode configuration. Φsaved,ideal and Φsaved,NPAC use the RHE and a nonphotoactive electrode with an identical catalyst as the dark electrode, respectively. They provide different information especially for differentiation of the roles of the photogenerating layer and catalyst. The best results were obtained with the Al/Ti metallic interlayer, with Φsaved,ideal and Φsaved,NPAC reaching 0.64% and 2.05%, respectively.

A large variety of nanoparticle-based delivery systems have become increasingly important for diagnostic and/or therapeutic applications. Yet, the numerous physical and chemical parameters that influence both the biological and colloidal properties of nanoparticles remain poorly understood. This complicates the ability to reliably produce and deliver well-defined nanocarriers which often leads to inconsistencies, conflicts in the published literature and, ultimately, poor translation to the clinics. A critical issue lies in the challenge of scaling-up nanomaterial synthesis and formulation from the lab to industrial scale while maintaining control over their diverse properties. Studying these phenomena early on in the development of a therapeutic agent often requires partnerships between the public and private sectors which are hard to establish. In this study, through the particular case of squalene-adenosine nanoparticles, we reported on the challenges encountered in the process of scaling-up nanomedicines synthesis. Here, squalene (the carrier) was functionalized and conjugated to adenosine (the active drug moiety) at an industrial scale in order to obtain large quantities of biocompatible and biodegradable nanoparticles. After assessing nanoparticle batch-to-batch consistency, we demonstrated that the presence of squalene analogs resulting from industrial scale-up may influence several features such as size, surface charge, protein adsorption, cytotoxicity and crystal structure. These analogs were isolated, characterized by multiple stage mass spectrometry, and their influence on nanoparticle properties further evaluated. We showed that slight variations in the chemical profile of the nanocarrier's constitutive material can have a tremendous impact on the reproducibility of nanoparticle properties. In a context where several generics of approved nanoformulated drugs are set to enter the market in the coming years, characterizing and solving these issues is an important step in the pharmaceutical development of nanomedicines.

Abstract Gold nanoparticles supported on carbon nanotubes were investigated as catalysts in the aerobic oxidation of various substrates (phenols, hydroquinones, catechols, aminophenols, and thiols). The nanohybrid system compares favorably with other supported noble metal catalysts in terms of overall efficacy as it operates at room temperature, under air atmosphere (no external oxidant needed), and can readily be recycled.

A novel nanohybrid structure was synthesized by assembling gold nanoparticles on polymerized polydiacetylene nanotubes. Combination of the nanohybrid with gallacetophenone afforded an efficient cooperative co-catalytic system for the oxidative coupling of primary amines into imines. The system is highly efficient and sustainable as it operates in high yields using minimal amounts of the metal and the quinone, under ambient atmosphere, at room temperature, in water, and is easily recycled.

We report an experimental study on the confinement of oligothiophene derivatives into single-walled carbon nanotubes over a large range of diameter (from 0.68 to 1.93 nm). We evidence by means of Raman spectroscopy and transmission electron microscopy that the supramolecular organizations of the confined oligothiophenes depend on the nanocontainer size. The Raman radial breathing mode frequency is shown to be monitored by both the number of confined molecules into a nanotube section and the competition between oligothiophene/oligothiophene and oligothiophene/tube wall interactions. We finally propose simple Raman criteria to characterize oligothiophene supramolecular organization at the nanoscale.

This paper explores how the Schottky barrier (SB) transistor is used in a variety of applications and material systems. A discussion of SB formation, current transport processes, and an overview of modeling are first considered. Three discussions follow, which detail the role of SB transistors in high performance, ubiquitous and cryogenic electronics. For high performance computing, the SB typically needs to be minimized to achieve optimal performance and we explore the methods adopted in carbon nanotube technology and two-dimensional electronics. On the contrary for ubiquitous electronics, the SB can be used advantageously in source-gated transistors and reconfigurable field-effect transistors (FETs) for sensors, neuromorphic hardware and security applications. Similarly, judicious use of an SB can be an asset for applications involving Josephson junction FETs.

Although the conventional methods for strong attachment of chitosan onto stainless steel require many steps in different solvents, it has been demonstrated in this work that covalent grafting of chitosan on a steel surface can be easily achieved through the formation of a self-adhesive surface based on aryldiazonium seed layers. Initially, a polyaminophenyl layer is grafted on a stainless steel surface by means of the one-step GraftFast(TM) process (diazonium induced anchoring process). The grafted aminophenyl groups are then converted to an aryldiazonium seed layer by simply dipping the substrate in a sodium nitrite acidic solution. That diazonium-rich grafted layer can be used as a self-adhesive surface for subsequent spontaneous coating of chitosan onto the steel surface. X-ray photoelectron and impedance electrochemical spectroscopies were used to characterize the pristine and modified steel samples. As evidenced from impedance and linear polarization results, the primary polyaminophenyl layer characterized by a high charge transfer resistance contributed to better protection against corrosion of the resulting chitosan-coated steel in sulfuric acid medium.

The paper presents complementary approaches based on experimental and numerical works to address the behavior of tokamak-relevant tungsten particles loaded with tritium. Sampling of particles inside the WEST tokamak have been realized thanks to an in situ particle collection system called Duster Box. This method allowed to identify various types of tungsten particles among them spherical shaped micro-particles between 5 µm and 30 µm in diameter. Based on these results a surrogate tungsten powder has been provided by means of spheroidization process and sieving method. Moreover, the powder tritium retention capacity was measured and specific activities of 90 MBq.g−1 and 280 MBq.g−1 were obtained for particles with 17 µm and 11.5 µm median diameters, respectively. Considering such tritium activities trapped in the particles, Monte-Carlo simulation were performed to estimate the electrostatic self-charging rates and the corresponding electrical charge carried by the radioactive tungsten dust. The results of these experiments provide robust data for the assessment of the dispersion of toxic/radioactive material in the environment that could follow a loss of containment.

A heterogeneous catalyst was assembled by stabilization of rhodium nanoparticles on carbon nanotubes.

Grafting of aminophenylene layer onto titanium nitride at different thicknesses can be achieved through the diazonium chemistry. The functionalized titanium nitride can find applications in areas: microelectronics, electrocatalysis, biosensors.

New one-dimensional (1D) hybrid nanosystems are elaborated with metalated or metal free phthalocyanine molecules encapsulated into the hollow core of single-walled carbon nanotubes. The X-ray diffraction experiments coupled to simulation allow evidencing the 1D structural organization of the molecules inside the nanotubes. The angle between the molecule ring and the nanotube axis is close to 32° as determined from our density functional theory calculations. Confined molecules display Raman spectra hardly altered with respect to the bulk phase, suggesting a rather weak interaction with the tubes. For comparison, noncovalent functionalization at the outer surface of the tube is also investigated. The vibrational properties of the molecules functionalized at the outer surface of tubes display important modifications. A significant curvature of the phthalocyanine is induced by the interaction with the tube walls, leading to change of the central atom position within the molecular ring, in good agreement with our first-principles calculations.

In the heart, cardiac function is regulated by the autonomic nervous system (ANS) that extends through the myocardium and establishes junctions at the sinus node and ventricular levels. Thus, an increase or decrease in neuronal activity acutely affects myocardial function and chronically affects its structure through remodeling processes. The neuro-cardiac junction (NCJ), which is the major structure of this system, is poorly understood and only a few cell models allow us to study it. Here, we present an innovant neuro-cardiac organ-on-chip model to study this structure to better understand the mechanisms involved in the establishment of NCJ. To create such a system, we used microfluidic devices composed of two separate cell culture compartments interconnected by asymmetric microchannels. Rat PC12 cells were differentiated to recapitulate the characteristics of sympathetic neurons, and cultivated with cardiomyocytes derived from human induced pluripotent stem cells (hiPSC). We confirmed the presence of a specialized structure between the two cell types that allows neuromodulation and observed that the neuronal stimulation impacts the excitation-contraction coupling properties including the intracellular calcium handling. Finally, we also co-cultivated human neurons (hiPSC-NRs) with human cardiomyocytes (hiPSC-CMs), both obtained from the same hiPSC line. Hence, we have developed a neuro-cardiac compartmentalized in vitro model system that allows us to recapitulate the structural and functional properties of the neuro-cardiac junction and that can also be used to better understand the interaction between the heart and brain in humans, as well as to evaluate the impact of drugs on a reconstructed human neuro-cardiac system.

Direct evidence for reductive and oxidative surface states coexisting in hematite nanostructures is given by combined STXM and PEC measurements. The annealing temperature and Ti substitution balance the surface states, driving the PEC activity.