Fonctionnalisation chimique contrôlée de l’oxyde de graphène

Graphene oxide is a promising nanomaterial thanks to its physicochemical characteristics. However, until today its exact composition remains still unknown. This is due to the complexity and non-stoichiometric character of this material.We started by investigating the surface composition of graphene oxide and its reactivity. We used differently synthesized samples to explore the relationship between the synthesis method and the surface composition. Furthermore, we functionalized graphene oxide with a chelating agent of radionuclides to study its biodistribution, and the impact of the lateral size. Afterwards, we tried different strategies for multifunctionalization with the aim to combine different properties. We observed that the dispersibility of graphene oxide often decreased after functionalization. Thus, we developed a highly water-stable graphene oxide sample by grafting awater-soluble polymer on its surface. Finally, we explored and improved the characterization methods for graphene oxide. Athorough investigation using different characterization techniques is fundamental to understand the modifications that the material underwent.L’oxyde de graphène est un nanomatériau prometteur grâce à ses caractéristiques physicochimiques. Cependant, jusqu’à aujourd’hui, sa composition exacte reste encore inconnue. Ceci est dû à la complexité et au caractère non-stoechiométrique de ce matériau. Nous avons commencé par étudier sa composition de surface et sa réactivité. Nous avons utilisé des échantillons synthétisés de manière différente pour explorer la relation entre la méthode de synthèse et la composition de surface. En outre, nous avons préparé un dérivé fonctionnalisé avec un agent chélatant de radionucléides pour étudier sa biodistribution et l’impact de la taille latérale.Par la suite, nous avons essayé plusieurs stratégies de multi-fonctionnalisation. L’avantage est de pouvoir combiner différentes propriétés. Nous avons observé que, souvent après la fonctionnalisation, la dispersabilité de l’oxyde de graphène diminue. Ainsi, nous avons développé un échantillon fonctionnalisé par un polymère soluble dans l’eau. Enfin, nous avons exploré et amélioré les méthodes de caractérisation de l’oxyde de graphène. Une caractérisation approfondie par différentes techniques est fondamentale pour comprendre les modifications que le matériau a subies

Fonctionnalisation chimique contrôlée de l’oxyde de graphène

L’oxyde de graphène est un nanomatériau prometteur grâce à ses caractéristiques physicochimiques. Cependant, jusqu’à aujourd’hui, sa composition exacte reste encore inconnue. Ceci est dû à la complexité et au caractère non-stoechiométrique de ce matériau. Nous avons commencé par étudier sa composition de surface et sa réactivité. Nous avons utilisé des échantillons synthétisés de manière différente pour explorer la relation entre la méthode de synthèse et la composition de surface. En outre, nous avons préparé un dérivé fonctionnalisé avec un agent chélatant de radionucléides pour étudier sa biodistribution et l’impact de la taille latérale.Par la suite, nous avons essayé plusieurs stratégies de multi-fonctionnalisation. L’avantage est de pouvoir combiner différentes propriétés. Nous avons observé que, souvent après la fonctionnalisation, la dispersabilité de l’oxyde de graphène diminue. Ainsi, nous avons développé un échantillon fonctionnalisé par un polymère soluble dans l’eau. Enfin, nous avons exploré et amélioré les méthodes de caractérisation de l’oxyde de graphène. Une caractérisation approfondie par différentes techniques est fondamentale pour comprendre les modifications que le matériau a subies.Graphene oxide is a promising nanomaterial thanks to its physicochemical characteristics. However, until today its exact composition remains still unknown. This is due to the complexity and non-stoichiometric character of this material.We started by investigating the surface composition of graphene oxide and its reactivity. We used differently synthesized samples to explore the relationship between the synthesis method and the surface composition. Furthermore, we functionalized graphene oxide with a chelating agent of radionuclides to study its biodistribution, and the impact of the lateral size. Afterwards, we tried different strategies for multifunctionalization with the aim to combine different properties. We observed that the dispersibility of graphene oxide often decreased after functionalization. Thus, we developed a highly water-stable graphene oxide sample by grafting awater-soluble polymer on its surface. Finally, we explored and improved the characterization methods for graphene oxide. Athorough investigation using different characterization techniques is fundamental to understand the modifications that the material underwent

Fonctionnalisation chimique contrôlée de l’oxyde de graphène

L’oxyde de graphène est un nanomatériau prometteur grâce à ses caractéristiques physicochimiques. Cependant, jusqu’à aujourd’hui, sa composition exacte reste encore inconnue. Ceci est dû à la complexité et au caractère non-stoechiométrique de ce matériau. Nous avons commencé par étudier sa composition de surface et sa réactivité. Nous avons utilisé des échantillons synthétisés de manière différente pour explorer la relation entre la méthode de synthèse et la composition de surface. En outre, nous avons préparé un dérivé fonctionnalisé avec un agent chélatant de radionucléides pour étudier sa biodistribution et l’impact de la taille latérale.Par la suite, nous avons essayé plusieurs stratégies de multi-fonctionnalisation. L’avantage est de pouvoir combiner différentes propriétés. Nous avons observé que, souvent après la fonctionnalisation, la dispersabilité de l’oxyde de graphène diminue. Ainsi, nous avons développé un échantillon fonctionnalisé par un polymère soluble dans l’eau. Enfin, nous avons exploré et amélioré les méthodes de caractérisation de l’oxyde de graphène. Une caractérisation approfondie par différentes techniques est fondamentale pour comprendre les modifications que le matériau a subies.Graphene oxide is a promising nanomaterial thanks to its physicochemical characteristics. However, until today its exact composition remains still unknown. This is due to the complexity and non-stoichiometric character of this material.We started by investigating the surface composition of graphene oxide and its reactivity. We used differently synthesized samples to explore the relationship between the synthesis method and the surface composition. Furthermore, we functionalized graphene oxide with a chelating agent of radionuclides to study its biodistribution, and the impact of the lateral size. Afterwards, we tried different strategies for multifunctionalization with the aim to combine different properties. We observed that the dispersibility of graphene oxide often decreased after functionalization. Thus, we developed a highly water-stable graphene oxide sample by grafting awater-soluble polymer on its surface. Finally, we explored and improved the characterization methods for graphene oxide. Athorough investigation using different characterization techniques is fundamental to understand the modifications that the material underwent

Different chemical strategies to aminate oxidised multi-walled carbon nanotubes for siRNA complexation and delivery

The carboxylic groups of oxidised multi-walled carbon nanotubes were directly converted into amino functions without extending the lateral chain. These nanotubes have been investigated as carriers for siRNA delivery.</p

Nose-to-Brain Translocation and Cerebral Biodegradation of Thin Graphene Oxide Nanosheets

Understanding the interactions of graphene oxide (GO)-based materials with biological systems is critical due to the potential applications of these materials. Here, we investigate the extent to which single- to few-layer GO sheets of different controlled lateral dimensions translocate from the nose to the brain following intranasal instillation. We explore tissue location and in vivo biodegradability of the translocated materials using various techniques. Mass spectrometry and confocal Raman analyses indicate that trace amounts of GO undergo nose-to-brain translocation in a size-dependent manner. The smallest GO-sheet size category (us-GO, 10-550 nm) gains the greatest access to the brain in terms of quantity and coverage. Confocal Raman mapping and immunofluorescence combinations show that in vivo, us-GO resides in association with microglia. Point-and-shoot Raman spectroscopy shows that trace quantities of us-GO are maintained over 1 month, but undergo biodegradation-related changes. This study adds to growing awareness regarding the fate of graphene-based materials in biological systems.This work was partially supported by the UKRI Engineering and Physical Sciences Research Council (UKRI EPSRC) NowNano Centre for Doctoral Training programs (EP/K016946/1 and EP/M010619/1), and the European Union (EU) 7th and 8th Framework Programmes for Research and Technological Development, Graphene Flagship project (FP7-ICT-2013-FET-F-604391 and H2020-FET-696656–Graphene Core 1). We gratefully acknowledge the Centre National de la Recherche Scientifique (CNRS), the International Center for Frontier Research in Chemistry (icFRC), and financial support from the Agence Nationale de la Recherche (ANR) through the LabEx project Chemistry of Complex Systems (ANR-10-LABX-0026_CSC).Peer reviewe

Immunological impact of graphene oxide sheets in the abdominal cavity is governed by surface reactivity

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Size-Dependent Pulmonary Impact of Thin Graphene Oxide Sheets in Mice:Toward Safe-by-Design

Safety assessment of graphene‐based materials (GBMs) including graphene oxide (GO) is essential for their safe use across many sectors of society. In particular, the link between specific material properties and biological effects needs to be further elucidated. Here, the effects of lateral dimensions of GO sheets in acute and chronic pulmonary responses after single intranasal instillation in mice are compared. Micrometer‐sized GO induces stronger pulmonary inflammation than nanometer‐sized GO, despite reduced translocation to the lungs. Genome‐wide RNA sequencing also reveals distinct size‐dependent effects of GO, in agreement with the histopathological results. Although large GO, but not the smallest GO, triggers the formation of granulomas that persists for up to 90 days, no pulmonary fibrosis is observed. These latter results can be partly explained by Raman imaging, which evidences the progressive biotransformation of GO into less graphitic structures. The findings demonstrate that lateral dimensions play a fundamental role in the pulmonary response to GO, and suggest that airborne exposure to micrometer‐sized GO should be avoided in the production plant or applications, where aerosolized dispersions are likely to occur. These results are important toward the implementation of a safer‐by‐design approach for GBM products and applications, for the benefit of workers and end‐users.This work was supported by the European Commission through the Future Emerging Technologies (FET) Graphene Flagship project (grant agreement no. 696656). This work was also partly supported by the Centre National de la Recherche Scientifique (CNRS), by the International Center for Frontier Research in Chemistry (icFRC) and by the Agence Nationale de la Recherche (ANR) through the LabEx project Chemistry of Complex Systems (ANR‐10‐LABX‐0026_CSC). A.F.R. wishes to acknowledge a studentship from the UKRI‐ Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in the Science and Applications of Graphene and Related Nanomaterials (GrapheneNOWNANO CDT; EP/L01548X/1). LN is indebted to EPSRC for his studentship in the framework of the UKRI‐EPSRC‐funded North West Nanoscience Doctoral Training Centre (NOWNANO DTC; EP/G03737X/1).Peer reviewe

Design, synthesis, characterization and properties of magnetic nanoparticle-nanocarbon hybrids

Carbon nanostructured materials such as carbon nanotubes and graphene oxide are attracting much attention due to their outstanding chemical and physical properties. Metal nanoparticle-decoration can provide additional functionalities to these nanocarbons. Many chemical methods are being used for the synthesis of these metal nanoparticle-functionalized nanocarbon hybrids. On the other hand, the outstanding properties of spinelle iron oxide magnetic (MAG) nanoparticles have been efficiently used for a variety of applications such as manipulation of biomolecules and cells, cancer hyperthermia, and medical devices. Therefore, MAG nanoparticle decoration of carbon nanotubes and graphene oxide can provide promising nanohybrid materials for nanobiotechnological applications. In this work, we present a straightforward chemical route for MAG nanopartide decoration of nanocarbon supports including carbon nanotubes and graphene oxide using in situ high-temperature decomposition method. This chemical methodology allows precisely controlling the MAG nanoparticle content, the MAG nanopartide size leading to a uniform coating on the different carbon supports. The properties of these new hybrids have been thoroughly evaluated. Our results show that the MAG nanoparticle decoration process strongly affects the structural and magnetic characteristics of the hybrids. The combination of MAG nanopartide and nanocarbon materials will open the door to their use in different domains including nanocomposites, wastewater treatment, sensors, biomaterials, and cancer therapy. (C) 2015 Elsevier Ltd. All rights reserved

Graphene, other carbon nanomaterials and the immune system:toward nanoimmunity-by-design

Carbon-based materials (CBMs), such as graphene, nanodiamonds, carbon fibers, and carbon dots, have attracted a great deal scientific attention due to their potential as biomedical tools. Following exposure, particularly intravenous injection, these nanomaterials can be recognized by immune cells. Such interactions could be modulated by the different physicochemical properties of the materials (e.g. structure, size, and chemical functions), by either stimulating or suppressing the immune response. However, a harmonized cutting-edge approach for the classification of these materials based not only on their physicochemical parameters but also their immune properties has been missing. The European Commission-funded G-IMMUNOMICS and CARBO-IMmap projects aimed to fill this gap, developing a functional pipeline for the qualitative and quantitative immune characterization of graphene, graphene-related materials (GRMs), and other CBMs. The goal was to open breakthrough perspectives for the definition of the immune profiles of these materials. Here, we summarize our methodological approach, key results, and the necessary multidisciplinary expertise ranging across various fields, from material chemistry to engineering, immunology, toxicology, and systems biology. G-IMMUNOMICS, as a partnering project of the Graphene Flagship, the largest scientific research initiative on graphene worldwide, also complemented the studies performed in the Flagship on health and environmental impact of GRMs. Finally, we present the nanoimmunity-by-design concept, developed within the projects, which can be readily applied to other 2D materials. Overall, the G-IMMUNOMICS and CARBO-IMmap projects have provided new insights on the immune impact of GRMs and CBMs, thus laying the foundation for their safe use and future translation in medicine