A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

PVP-capped silver nanoparticles with a diameter of the metallic core of 70 nm, a hydrodynamic diameter of 120 nm and a zeta potential of −20 mV were prepared and investigated with regard to their biological activity. This review summarizes the physicochemical properties (dissolution, protein adsorption, dispersability) of these nanoparticles and the cellular consequences of the exposure of a broad range of biological test systems to this defined type of silver nanoparticles. Silver nanoparticles dissolve in water in the presence of oxygen. In addition, in biological media (i.e., in the presence of proteins) the surface of silver nanoparticles is rapidly coated by a protein corona that influences their physicochemical and biological properties including cellular uptake. Silver nanoparticles are taken up by cell-type specific endocytosis pathways as demonstrated for hMSC, primary T-cells, primary monocytes, and astrocytes. A visualization of particles inside cells is possible by X-ray microscopy, fluorescence microscopy, and combined FIB/SEM analysis. By staining organelles, their localization inside the cell can be additionally determined. While primary brain astrocytes are shown to be fairly tolerant toward silver nanoparticles, silver nanoparticles induce the formation of DNA double-strand-breaks (DSB) and lead to chromosomal aberrations and sister-chromatid exchanges in Chinese hamster fibroblast cell lines (CHO9, K1, V79B). An exposure of rats to silver nanoparticles in vivo induced a moderate pulmonary toxicity, however, only at rather high concentrations. The same was found in precision-cut lung slices of rats in which silver nanoparticles remained mainly at the tissue surface. In a human 3D triple-cell culture model consisting of three cell types (alveolar epithelial cells, macrophages, and dendritic cells), adverse effects were also only found at high silver concentrations. The silver ions that are released from silver nanoparticles may be harmful to skin with disrupted barrier (e.g., wounds) and induce oxidative stress in skin cells (HaCaT). In conclusion, the data obtained on the effects of this well-defined type of silver nanoparticles on various biological systems clearly demonstrate that cell-type specific properties as well as experimental conditions determine the biocompatibility of and the cellular responses to an exposure with silver nanoparticles

Retour sur 10 questions en Sciences de l’information et de la communication

Études de communication fête son 50e numéro en 2018 et célèbre cet événement en publiant un numéro spécial dont l’objectif est d’ouvrir la discussion sur 10 questions qui ont marqué la vie de la revue. Des chercheurs en sciences de l’information et de la communication, reconnus dans leur domaine, les réexaminent en se référant aux dossiers publiés depuis 35 ans dans notre revue et en les situant dans leurs enjeux actuels. Sont ainsi abordés : le design informationnel, l’organisation des connaissances, les métamorphoses du document, la médiation culturelle, la culture informationnelle, espace public et production de l’information, média et territoire, l’évolution des approches organisationnelles, industrialisation de la formation, pratiques d’écriture et pratiques professionnelles. En interrogeant la manière dont la revue a participé à la construction de la réflexion en sciences de l’information et de la communication, chaque auteur éclaire une de ces questions à partir de ses propres recherches et des travaux développés dans l’ensemble du champ considéré

Images de territoires et « travail territorial » des médias

Ce numéro d’Études de Communication se donne pour objet d’étudier les images et imaginaires de territoires produits, entretenus, « travaillés » par les médias, locaux et nationaux. Comment l’information – entendue à partir de la variété de ses supports et de ses formats médiatiques – participe de la construction territoriale, envisagée comme opération symbolique, comme structuration identitaire, comme élaboration collective ? L’intention est ainsi de cerner ce que l’on peut identifier comme « travail territorial », d’étudier en quoi les médias font médiation dans le rapport au(x) territoire(s). Dans le contexte du déploiement de stratégies de reconfiguration territoriale, d’évolution des formes de l’engagement public et des pratiques culturelles/médiatiques des individus, cette livraison se propose de mettre l’accent tant sur la question du rapport au lieu – en quoi et comment les médias parlent des lieux et des espaces, qu’ils contribuent à configurer, dans et par les contenus qu’ils produisent et les structures signifiantes qu’ils agencent – que sur celle du sens des lieux entretenu et façonné par les médias, et par là sur les images et imaginaires ainsi associés aux lieux. The purpose of this issue of Études de Communication is to study the images and imagination of territories produced, structured, and “worked” by the local and national media. How does information—understood based on the variety of its supports and media formats—participate in the territorial construction, seen as a symbolic operation, as structuring identity, as collective elaboration? The intention is then to understand what can be called “territorial work,” to study how medias make media in relation to territory or territories. In the context of strategies of territorial reconfiguration, the evolution of forms of public involvement and cultural/media practices of individuals, this issue proposes to accent as much the relationship to place—why and how media talks about places and spaces that it contributes to configuring, in and by the contents it produces and the meaningful structures they advance—as the meaning of the places structured and fashioned by the media and the images and imaginations thus associated with such places

PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

PVP-capped silver nanoparticles with a diameter of the metallic core of 70 nm, a hydrodynamic diameter of 120 nm and a zeta potential of −20 mV were prepared and investigated with regard to their biological activity. This review summarizes the physicochemical properties (dissolution, protein adsorption, dispersability) of these nanoparticles and the cellular consequences of the exposure of a broad range of biological test systems to this defined type of silver nanoparticles. Silver nanoparticles dissolve in water in the presence of oxygen. In addition, in biological media (i.e., in the presence of proteins) the surface of silver nanoparticles is rapidly coated by a protein corona that influences their physicochemical and biological properties including cellular uptake. Silver nanoparticles are taken up by cell-type specific endocytosis pathways as demonstrated for hMSC, primary T-cells, primary monocytes, and astrocytes. A visualization of particles inside cells is possible by X-ray microscopy, fluorescence microscopy, and combined FIB/SEM analysis. By staining organelles, their localization inside the cell can be additionally determined. While primary brain astrocytes are shown to be fairly tolerant toward silver nanoparticles, silver nanoparticles induce the formation of DNA double-strand-breaks (DSB) and lead to chromosomal aberrations and sister-chromatid exchanges in Chinese hamster fibroblast cell lines (CHO9, K1, V79B). An exposure of rats to silver nanoparticles in vivo induced a moderate pulmonary toxicity, however, only at rather high concentrations. The same was found in precision-cut lung slices of rats in which silver nanoparticles remained mainly at the tissue surface. In a human 3D triple-cell culture model consisting of three cell types (alveolar epithelial cells, macrophages, and dendritic cells), adverse effects were also only found at high silver concentrations. The silver ions that are released from silver nanoparticles may be harmful to skin with disrupted barrier (e.g., wounds) and induce oxidative stress in skin cells (HaCaT). In conclusion, the data obtained on the effects of this well-defined type of silver nanoparticles on various biological systems clearly demonstrate that cell-type specific properties as well as experimental conditions determine the biocompatibility of and the cellular responses to an exposure with silver nanoparticles