In Vitro Dermal Safety Assessment of Silver Nanowires after Acute Exposure: Tissue vs. Cell Models

Silver nanowires (AgNW) are attractive materials that are anticipated to be incorporated into numerous consumer products such as textiles, touchscreen display, and medical devices that could be in direct contact with skin. There are very few studies on the cellular toxicity of AgNW and no studies that have specifically evaluated the potential toxicity from dermal exposure. To address this question, we investigated the dermal toxicity after acute exposure of polymer-coated AgNW with two sizes using two models, human primary keratinocytes and human reconstructed epidermis. In keratinocytes, AgNW are rapidly and massively internalized inside cells leading to dose-dependent cytotoxicity that was not due to Ag+ release. Analysing our data with different dose metrics, we propose that the number of NW is the most appropriate dose-metric for studies of AgNW toxicity. In reconstructed epidermis, the results of a standard in vitro skin irritation assay classified AgNW as non-irritant to skin and we found no evidence of penetration into the deeper layer of the epidermis. The findings show that healthy and intact epidermis provides an effective barrier for AgNW, although the study does not address potential transport through follicles or injured skin. The combined cell and tissue model approach used here is likely to provide an important methodology for assessing the risks for skin exposure to AgNW from consumer products

Utilisation de lamelle avec repères pour la culture cellulaire et l’observation des cellules en microscopie optique et électronique

National audienc

Design and synthesis of novel hybrid metal complex–DNA conjugates: key building blocks for multimetallic linear DNA nanoarrays

International audienc

Development of a sialic acid-containing hydrogel of poly[N-(2-hydroxypropyl) methacrylamide]: characterization and implantation study.

International audienceThis study describes the preparation and the characterization of poly[ N-(2-hydroxypropyl methacrylamide)] hydrogel with bulk-modified saccharidic portion of ganglioside GM 3 (Neu5Ac-alpha2,3-Gal-beta1,4-Glc). The 3'-sialyllactose is a bioactive epitope recognized by many cell surface receptors on viruses, bacteria, and human cells such as growth factor receptors. Acrylated 3'-sialyllactose was synthesized and incorporated into the macromolecular network of hydrogels by free radical cross-linking copolymerization. Fluorescence techniques coupled to confocal laser scanning microscopy was employed to characterize the binding and accessibility of the sialyl group in the polymer network by using a monoclonal antibody against GM 3 and the lectin wheat germ agglutinin. The morphology of the network was examined by scanning electron microscopy and confocal microscopy to image the gel morphology. The water content of sialyllactosyl-HPMA hydrogel compared to unmodified gel was characterized by swelling measurements and thermogravimetry. A preliminary implantation study in rat brain was performed to examine the biofunctionality of the sialyllactosyl hydrogel using an experimental model of Parkinson's disease

Dark Field Transmission Electron Microscopy Imaging for Biological and Soft Matter Systems

International audienceIn this study, we present a new application of the transmission electron microscopy dark field mode for cell imaging. We have applied this imaging mode to two types of cellular systems: human HeLa cells to analyze molecular membrane systems and HC11 mouse mammary cells containing lipid molecule droplets. We have also studied a third macromolecular system, copolymer nanoparticles for the characterization of core-shell structures. We want to show the effective use of diffraction contrast, even on amorphous systems for increasing the image contrast and the signal/noise ratio. We discuss the TEM dark field advantages for the analysis of polymers and other macromolecular systems, including biological, systems compared to the bright field mode

Thiol-ene clickable hyaluronans: From macro-to nanogels

International audienc

Thermoresponsive Self-Assemblies of Cyclic and Branched Oligosaccharide- block -poly( N -isopropylacrylamide) Diblock Copolymers into Nanoparticles

International audienc

Dark Field Transmission Electron Microscopy Imaging for Biological and Soft Matter Systems

International audienceIn this study, we present a new application of the transmission electron microscopy dark field mode for cell imaging. We have applied this imaging mode to two types of cellular systems: human HeLa cells to analyze molecular membrane systems and HC11 mouse mammary cells containing lipid molecule droplets. We have also studied a third macromolecular system, copolymer nanoparticles for the characterization of core-shell structures. We want to show the effective use of diffraction contrast, even on amorphous systems for increasing the image contrast and the signal/noise ratio. We discuss the TEM dark field advantages for the analysis of polymers and other macromolecular systems, including biological, systems compared to the bright field mode