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A substantial increase in engineered nanoparticles in consumer products has been observed, heightening human and environmental exposure. Inhalation represents the primary route of human exposure, necessitating a focus on lung toxicity studies. However, to avoid ethical concerns the use of in vitro models is an efficient alternative to in vivo models. This study utilized an in vitro human alveolar barrier model at air-liquid-interface with four cell lines, for evaluating the biological effects of different gold nanoparticles. Exposure to PEGylated gold nanospheres, nanorods, and nanostars did not significantly impact viability after 24 h, yet all AuNPs induced cytotoxicity in the form of membrane integrity impairment. Gold quantification revealed cellular uptake and transport. Transcriptomic analysis identified gene expression changes, particularly related to the enhancement of immune cells. Despite limited impact, distinct effects were observed, emphasizing the influence of nanoparticles physicochemical parameters while demonstrating the model's efficacy in investigating particle biological effects.

The current study presents for the very first time to our knowledge the synthesis, characterization, and application of regio-selectively modified dendritic silica particles (RMDS) in tire rubber composites. So far, no study has ever reported mesoporous silica bringing greater mechanical properties than small fractal precipitated silica. With mechanical testing (DMA, tensile strength) and advanced imaging (TEM-EDS, HIM-SIMS, micro-CT), it was demonstrated that dendritic particles enable superior mechanical reinforcement of rubber-based nanocomposites without any drawback as usually reported with fractal fillers. On one side, their modified porous surface mimics the porous aggregates formed by classic fillers, enabling the rubber chains to permeate the pores and closely interact with the particles. On the other side, unlike fractal fillers, RMDS consist of single particles instead of aggregates, and therefore do not suffer as much from the Payne effect and irreversible dislocations under mechanical solicitations. Also, the excellent dispersibility of RMDS allows to combine them with small amount of fractal filler. Dual filler composite shows superior mechanical performances versus materials using one filler family, leading to higher reinforcement, better traction and rolling resistance indicators. The use of porous particles as “unbreakable” fillers for rubber with a small amount of fractal silica as additive fillers paves the way for novel reinforcing dual-filler systems to be used in disruptive tires technology.

This work focuses on the cross-sectional characterization of the protective conversion layer formed on AA2024-T3 by lithium-leaching from a polyurethane coating in a corrosive environment. The layer shows a multi-layered arrangement comprising nanoscopic local phases. Transmission electron microscopy (TEM) and complementary high-resolution secondary ion mass spectroscopy (SIMS) were employed to observe the cross-sections of the entire layer formed at different locations of a 1-mm-wide scribe, in terms of morphology, structure and chemical composition. The conversion layer was comprised of two ubiquitous sublayers; a thin dense layer (i.e. 150 nm) adjacent the alloy substrate and a porous layer. The former represents an amorphous lithium-containing pseudoboehmite phase, Li-pseudoboehmite, whereas the latter is composed of amorphous and crystalline products; an outer columnar layer merely seen on the peripheral region is also crystalline. Through a sandwich structure and the d(003) basal spacing, the crystalline phases were identified as Li-Al layered double hydroxide. Although lithium was found uniformly spread within different regions, the local phases with no/low concentration of lithium were revealed with energy filtered TEM and confirmed with SIMS analysis., (OLD) MSE-6, QN/Afdelingsbureau, QN/Zandbergen Lab

The use of nanoSIMS for the exploration of microbial activities in natural habitats often implies that stable isotope tracer experiments are combined with in situ hybridization techniques (i.e. fluorescence in situ hybridization (FISH) or catalyzed reporter deposition (CARD)-FISH). In this study, Pseudomonas putida grown on 13C- and 15N-labeled carbon and nitrogen, collected in exponential growth and stationary phases, was hybridized and analyzed by nanoSIMS. It was shown that 13C and 15N fractions decreased after FISH and CARD-FISH in comparison to chemically untreated cells. However, the fractions were influenced differently by various treatments. After paraformaldehyde fixation of exponentially growing cells, a reduction of the 13C and 15N fractions was measured from 94 ± 1.2% and 89.5 ± 3.8% to 90.2 ± 0.8% and 64 ± 4.6%, respectively, indicating that nitrogen isotopic composition was most influenced. A further decrease of the 13C and 15N fractions to 80.7 ± 6.5 and 59.5 ± 4.1%, respectively, was measured after FISH, while CARD-FISH decreased the fractions to 57.4 ± 3.0% and 47.1 ± 4.1%, respectively. The analysis of cells collected in different growth phases revealed that the effect of various treatments seemed to be dependent on the cell's physiological state. In addition, a mathematical model that can be used in further studies was developed in order to calculate the amount of carbon introduced into the cells by chemical treatments. These results can be valuable for environmental FISH-nanoSIMS studies where the isotopic composition of single cells will be used to quantitatively assess the importance of specific populations to certain biochemical processes and determine budget estimations.

This study aims to assess the effects of Ag particles synthesised by a chemical (Ag 20, 200 nm) and biological method (Ag 23, 27 nm) in aquatic organisms the bacterium Vibrio fischeri, the alga Desmodesmus subspicatus and the crustacean Daphnia magna. Ag particles exerted toxic effects in all organisms studied with Ag particles 23 nm being the most potent. Although soluble Ag was released in all media, the differences between the tested Ag particles still cannot be explained solely based on soluble Ag. NanoSIMS analysis performed with D. magna showed that apart from their localisation in the gut lumen, Ag 200 nm and Ag NPs 23 nm seemed to pass through the epithelial barrier as well. Ag NPs 23 nm localised in specific areas seemed to be within the ovaries. This study strengthens the argument that size, method of synthesis as well as surface chemistry may affect the uptake and toxic effects of Ag NPs. © Informa UK, Ltd.

The main function of the thyroid gland is to make hormones, T4 and T3, which are essential for the regulation of metabolic processes throughout the body. Caveolae harbour is the key enzymes involved in this iodide organification. The analyses of thyroids from normal mice and caveolin-1 Knockout mice (mice deficient in caveolin) have been performed using the SIMS imaging. In the thyroid of control mice, the epithelium is homogeneous and iodine (I-127) is observed in the follicle lumen. In Knockout mice, we observe an accumulation of intracellular vesicles and apoptotic nuclei resulting from oxidative stress due to H2O2 overproduction also inducing apical lesions of the thyrocytes, at the site of iodine organification and H2O2 generation. We also observe in the Knockout mice an accumulation of I-127 in the cellular cytoplasm and an absence of the iodine in some follicular lumina, indicating a problem at the level of iodine organification. Crown Copyright (C) 2008 Published by Elsevier B. V. All rights reserved.

The surface behaviour of a two-phase polymer mixture depends on the chemical structure of the polymer components, the interaction between the two polymers and the processing conditions. The microscopic morphology and the surface composition need to be known in order to fully utilize the thin film properties. The technique of static time-of-flight secondary ion mass spectrometry (ToF-SIMS) is used to obtain the molecular surface composition of thin films of blends and block copolymers. The depth profiling tool of Nano-SIMS, a dynamic SIMS technique, helps to provide the chemical mapping of the surface in 2D and 3D. The surface morphology is investigated using AFM. Thin films of PS and PMMA diblock copolymers with molecular weight of 12K-12K and 10K-10K and blends of PS/PMMA (10K/10K) for thicknesses ranging from 5 nm to 50 nm are examined. For the blends, the ToF-SIMS spectra for all the thicknesses show the same behaviour of a high increase of PMMA on the surface after annealing. Nano-SIMS images reveal the formation of nanostructures on the annealed surfaces and AFM studies show these nanostructures to be droplets having distinct phase shift from the surrounding matrix. The droplet dimensions increase with the increase of the thickness of the film but the absolute intensity from the ToF-SIMS spectra for all the annealed films remains almost the same. For the copolymers, the ToF-SIMS spectra show that there is a decrease of PMMA on the surface for the annealed films when compared to the as-cast ones. AFM morphology reveals that, for different thicknesses, annealing induces different topographical features like droplets, holes, spinodal patterns, etc. but with no distinct phase shift between the patterns and the surrounding matrix. The two different copolymers of comparable molecular weight are found to exhibit very different topography even when the thickness of the films remained the same. The surface composition from the ToF-SIMS data, however, was not found to va

Immiscible polymer systems are known to form various kinds of phase-separated structures capable of producing self-assembled patterns at the surface. In this study, different surface characterization methods were utilized to study the surface morphology and composition produced after annealing thin polymer films. Two different SIMS techniques - static time-of-flight secondary ion mass spectrometry (ToF-SIMS) and dynamic nano-SIMS - were used, complemented by x-ray photoelectron spectrometry (XPS) and atomic force microscopy (AFM). Thin films (spin-coated onto silicon wafers) of polystyrene (PS)-poly(methyl methacrylate) (PMMA) symmetric blends and diblock copolymers of similar molecular weight were investigated. Surface enrichment by PS was found on all as-cast samples. The samples were annealed at 160° C for different time periods, after which the blend and the copolymer films exhibited opposite behaviour as seen by ToF-SIMS and XPS. The annealed blend surface presented an increase in the PMMA concentration whereas that of copolymers showed a decrease in PMMA concentration compared with the as-cast sample. For blends, the nano-SIMS as well as AFM images revealed the formation of phase-separated domains at the surface. The composition information obtained from ToF-SIMS and XPS, as well as the surface mapping by nano-SIMS and AFM, allowed us to conclude that PS formed phase separated droplet-like domains on a thin PMMA matrix on annealing. The three-dimensional nano-SIMS images showed that the PS droplets were supported inside a rim of PMMA and that these droplets continued from the surface like columnar rods into the film until the substrate interface. In the case of annealed copolymer samples, the AFM images revealed topographical features resembling droplet-like domains on the surface but there was no phase difference between the domains and the matrix. In the case of copolymers, owing to the covalent bonding between the blocks, complete phase separation was n