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During their lifecycle, many engineered nanoparticles (ENPs) undergo significant transformations that may modify their toxicity, behaviour, and fate in the environment. Therefore, understanding the possible environmentally relevant transformations that ENPs may undergo as a result of their surroundings is becoming increasingly important. This work considers industrially produced ceria (CeO 2) and focuses on a particle library consisting of seven zirconium-doped variants (Ce 1-x Zr x O 2) where the Zr doping range is x = 0–1. The study assesses their potential transformation in the presence of environmentally relevant concentrations of phosphate. These ENPs have an important role in the operation of automotive catalysts and therefore may end up in the environment where transformations can take place. Samples were exposed to pH adjusted (c. 5.5) solutions made up of either 1 mM or 5 mM each of KH 2 PO 4 , citric acid and ascorbic acid and the transformed particles were characterised by means of DLS – size and zeta potential, UV/VIS, TEM, FT-IR, EDX and XRD. Exposure to the phosphate solutions resulted in chemical and physical changes in all ceria-containing samples to cerium phosphate (with the monazite structure). The transformations were dependent on time, ceria concentration in the particles (Ce:Zr ratio) and phosphate to ceria ratio. The presence of Zr within the doped samples did not inhibit these transformations, yet the pure end member ZrO 2 ENPs showed no conversion to phosphate. The quite dramatic changes in size, structure and composition observed raise important questions regarding the relevant form of the materials to investigate in ecotoxicity tests, and for regulations based on one or more dimensions in the nanoscale. Image 1 • Transformations of Ce 1-x Zr x O 2 NPs following exposure to environmentally relevant phosphate solutions. • Results showed physical and chemical transformations for only the ceria-containing NPs. • Transformations were dependent on time, Ce concentration and H 2 PO 4 −: Ce ratios. • Ceria-rich nanoparticles transformed into "sea urchin"/needle-like structures. • Samples underwent compositional transformation to phosphate-bearing phases. On exposure to a pH adjusted phosphate based solution, Ce 1-x Zr x O 2 ENPs underwent physical (i.e. size, structure) and chemical (i.e. composition) transformations. [ABSTRACT FROM AUTHOR]

Understanding the environmental behaviour of nanoparticles (NPs) after release into aquatic systems is essential to predict the environmental implications of nanotechnology. Silver nanoparticles (AgNPs) represent a major class of engineered NPs with a significant potential for environmental impact. Therefore, investigating their transformations in natural waters will help predict their long term environmental fate and behaviour. AgNPs were characterized in natural lake water collected seasonally from the same freshwater source, using column microcosms to assess their behaviour and transport at different depths. Building on our previous work using similar systems with synthetic waters, the influence of water chemistry and NP surface modifications on colloidal stability and dissolution in natural lake water over time was investigated. A simple sedimentation-diffusion model parameterized by the particle properties and total Ag concentration was successfully used to understand AgNPs transport behaviour. PVP coated AgNPs remained colloidally stable, with their transport in the water column dominated by diffusion, and exhibited no significant or substantial changes in data or model parameters for different seasons. Citrate coated AgNPs were susceptible to rapid aggregation, sedimentation, dissolution and reprecipitation; their transport in the water column was determined by both diffusion and sedimentation. [ABSTRACT FROM AUTHOR]

Sub-micron plastics (SMPs, size < 1 µm) are potentially taken up by plants. Serious concerns arise that how far SMPs can transfer from plants into food webs. Here, we show that lettuce takes up 250 nm gadolinium labelled polystyrene (PS) and polyvinyl chloride (PVC) SMPs from the soil. The polymer type influences the biodistribution of the particles in lettuce (roots and leaves) and the number of particles transferred from the plants to insects feeding on the treated lettuce. The SMPs were further transferred from insects to insect-feeding fish to accumulate mostly in the fish liver. No Gd was released from the particles upon biotransformation (formation of protein corona on the particles) in the plants or insects. However, Gd ion was detected in fish fed with PS-SMP treated insects, indicating the possible degradation of the particles. No biomagnification in fish was detected for either type of SMPs. We conclude that plastic particles can potentially transfer from soil into food webs and the chemical composition of plastics influences their biodistribution and trophic transfer in organisms. [Display omitted] • Lettuce takes up 250 nm polystyrene and polyvinyl chloride SMPs from the soil. • SMPs transfer from lettuce → insect → fish but no biomagnification has occurred. • The polymer type influences the biodistribution of SMPs in the organisms. • The SMPs accumulate mostly in the fish liver. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) have important technological applications resulting in an increased potential for release to the environment, and a greater possibility of toxicological effects. The marine bivalve Scrobicularia plana was exposed to AuNPs of size 5, 15 and 40nm during a 16 d laboratory exposure at 100μg Au L−1. After exposure to AuNPs forming aggregates (>700nm), the clams accumulated Au in their soft tissues. Biochemical (biomarkers) and behavioral (burrowing and feeding) responses were investigated. Au NPs were responsible of metallothionein induction (5, 40nm), increased activities of catalase (15, 40nm) and superoxide dismutase (40nm) and of glutathione S-transferase by the three sizes of AuNPs indicating defense against oxidative stress. Exposure to AuNPs impaired burrowing behavior. However, it must be underlined that these effects were observed at a dose much higher than expected in the environment. [Copyright &y& Elsevier]

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (67Zn) ZnO nanoparticles and measured the uptake of 67Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 μg g−1). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 μg g−1 which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions. [Copyright &y& Elsevier]

Struvite crystallisation is widely studied as a way to remove phosphorus from wastewater effluents and simultaneously generates a valuable product for the fertiliser industry. However, to date, some crystallisation processes experimented at either pilot/or full scale face problems linked to the formation of fines. This paper presents results on the investigation of struvite agglomerative properties and the possible application of coagulants and/or flocculants to remove fines. Coagulants investigated were hydrolysing metals salts (Al3+ and Fe3+), calcium compounds and a cationic polymer, polydiallyldimethylammoniumchloride (polyDADMAC). The effects of a natural flocculant (alginate) have also been tested. Results demonstrated that destabilisation of struvite particles by chemical addition was feasible and identified polyDADMAC as a good option for the agglomeration of struvite particles. However, optimisation of its dosage under typical pH conditions for struvite formation showed floc formation to be very pH sensitive. [Copyright &y& Elsevier]

[Display omitted] The world expects solutions to a multitude of technological challenges, from curing disease to mitigating climate change, from increasingly more "clever" or "advanced" materials. But how do we address the safety of ever more novel substances and what have we learned from the last 15 years of nanosafety research? In this opinion letter, we 1 1 The three authors currently serve as the coordination team of the Nanosafety Cluster (www.nanosafetycluster.eu). The views presented in this paper, however, are their own and may not represent those of other members of the Nanosafety Cluster. share our views on how to develop a framework for these new families of materials, that capitalizes on the nanosafety progress achieved to date, and how to ensure the wider nanoscience community could play a part in this new challenge. [ABSTRACT FROM AUTHOR]

• The sub-micron fraction of microplastics dominates on a particle number basis. • The biological fate of sub-micron plastics (SMP) in organisms is poorly understood. • No method is avialable yet for identification and quantifiction of SMP in organisms. • An extraction, concentration, characterisation workflow for SMP in biota is presented. • Metal-doping of polymeric particles may circumvent current analytical limitations. [Display omitted] The current debate on hazards associated with sub-micron sized plastics is hampered by a lack of quantitative data on the uptake and biological fate of plastics in organisms. Analytical methods should be developed to identify, characterize, and quantify sub-micron particulate plastic in biota to understand their biological fate in terms of biodistribution, localization, bioaccumulation and clearance. Here we give a perspective on a promising workflow of sample preparation methods and techniques that could enable analysis of sub-micron plastics in biological matrices and discuss their application for biological fate studies of particulate plastic in organisms. We also expect these methods to be largely transferrable to studies considering sub-micron plastics in food, consumer products, human and some environmental compartments. [ABSTRACT FROM AUTHOR]

• Intranasal exposure to ZnO NPs affect cholinergic neurotransmission in rat brain. • The release of key neurotransmitter acetylcholine (ACh) is increased. • ACh synthesis is enhanced and the vesicular ACh transporter is upregulated. • AChE activity is suppressed by Zn-AChE interaction or a down-regulation mechanism. • The observed biological effects are mainly derived from released Zn2+. The neurotoxicity of inhaled ZnO nanoparticles (NPs) and the underlying mechanisms remain largely unknown. In this study, ZnO NPs (30 ± 6 nm) were intranasally instilled to rats via a single dose (13 mg Zn/kg BW), with ZnSO 4 as the ionic control, and analysis 7-days post exposure. The hippocampus was found to be the main target for Zn accumulation for both ZnO NPs and ZnSO 4. Synchrotron radiation based X-ray absorption fine structure (XAFS) analysis showed that no particulate ZnO was found, suggesting the occurrence of dissolution and transformation of ZnO NPs. Multi-omics analysis, including transcriptomics, proteomics and metabolomics, demonstrated that cholinergic neurotransmission was the main biological process affected following both treatments. The release of the key neurotransmitter acetylcholine (ACh) was increased by enhanced ACh synthesis, upregulation of vesicular ACh transporter, and suppression of the activity of ACh hydrolysis enzyme (AChE), either by direct Zn-AChE interaction or a transcriptional down-regulation mechanism. In addition, ZnO NPs and ZnSO 4 induced similar molecular consequences and exhibited the same Zn chemical speciation (100 % of Zn complexes) in the hippocampal region evidenced by XAFS analysis, suggesting that the observed biological effects were mainly derived from Zn2+ released from the ZnO NPs. This study not only evidences a new pathway for the impact of ZnO NPs on the brain, but also identifies the origin of the impact as ionic Zn, which provides the basis for safe-by-design of ZnO NPs. [ABSTRACT FROM AUTHOR]

The northwestern Euboea Island and the neighboring part of the mainland in eastern Central Greece, i.e. Sperchios area, contain several hot springs and active thermogenic travertine deposits, which are the surface manifestations of an active hydrothermal system, controlled by active tectonics, and supplied with heat by a 7–8 km deep magma chamber, with surface manifestation, the Plio-Pleistocene trachyandesitic volcanic center of Lichades. This hydrothermal system is fueled by a mixture of seawater and deep magmatic fluid with only limited meteoric water contribution. Thermal water samples show extreme pH, temperature and Electrical Conductivity values, with maximum values always recorded in two locations (Aedipsos and Ilia). The observed similarities in fluid compositions for most of the analyzed anions, major and trace elements, suggesting a stronger hydrothermal signature for the Northern Euboea area, perhaps reflecting greater proximity to the heat source of the hydrothermal system. The hydrothermal fluids collected and analysed were found to be highly enriched in a number of metallic and non-metallic elements e.g. up to 100 μg/L As, up to 1.1 wt.% Fe, up to 340 μg/L Ba, up to 65 μg/L Cu, up to 2.1 wt.% Cl, up to 3700 mg/L SO 4 2 − , up to 390 μg/L Se. Some of the enrichments are reflected directly in the travertines lithogeochemistry and the metallic mineral phases found inside the travertines. A number of mineral phases including sulfides (such as pyrite, arsenopyrite, galena, chalcopyrite, sphalerite and stibnite), native elements (such as Pb and Ni), alloys (such as Au ± Cu-Ag) fluorite and REE-bearing phases (such as Ce-, Nd- and La-bearing members of hydroxylbastnäsite, cackinsite, lanthanite and sahamalite) were identified syngenetically enclosed as clastic grains within the pores of all studied travertines; the ore grade concentrations of some iron-rich travertines (up to 28.9 wt.% Fe and up to 1.83 wt.% As), as well as the high concentration of precious and base metals at the hydrothermal fluid, strongly suggest active mineralizing processes throughout the studied system. Travertines containing elevated Fe ± As and consisting of ferrihydrite in addition to aragonite/calcite, were deposited on the surface, most likely after mixing of ascending reducing hydrothermal fluids with cool seawater. The high REE content in the Fe ± As-rich travertines (up to ~ 465 mg/kg ΣREE) is caused by adsorption of REE-bearing phases by iron oxyhydroxides. Mineralogical and geochemical evidence (such as the presence of elements in their native form, of alloys such as Au ± Cu-Ag, the enrichment of metalloids and the abundance of REE) may indicate magmatic contribution to the hydrothermal system and accordingly to the studied travertines. We support the hypothesis that metals and metalloids were mainly derived from magmatic fluids, which successively mixed with heated-, and with oxygenated, cool seawaters at depth and on the surface respectively, resulting in the deposition of carbonate-hosted sulfide mineralization at depth, and of Fe ± As-rich travertines at the surface. The northwestern Euboea Island and Sperchios area hydrothermal system represents the first documented active terrestrial mineralizing hydrothermal system associated with ore-bearing travertines in Greece. [ABSTRACT FROM AUTHOR]

This critical review provides a detailed Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis of carbon nanodots (CDs) synthesised using green chemistry principles, focusing on their potential for safe and sustainable innovation. CDs offer significant strengths, such as eco-friendly synthesis, biocompatibility, and tunable optical properties, making them promising candidates for applications in bioimaging, drug delivery, and environmental monitoring. However, several weaknesses, including low quantum yield, reproducibility issues, heterogeneity, and scalability challenges, limit their widespread commercial adoption. The analysis emphasises the crucial role that integrating green chemistry, and Safe and Sustainable by Design (SSbD) innovations can play in overcoming these limitations. These approaches provide pathways to improve the consistency and scalability of CDs production without compromising environmental and human health. The review also highlights key opportunities, such as advancing synthesis techniques, optimising purification processes, and integrating CDs with other nanomaterials to enhance their properties and broaden their applications. By addressing these challenges and capitalising on the strengths and opportunities identified, the development of green-synthesised CDs can move toward a more sustainable, scalable, and industrially viable future. This review highlights the importance of standardisation and continued innovation in synthesis methods to foster the widespread adoption of green chemistry in nanotechnology. Applying SWOT analysis to green-synthesised carbon dots, guiding sustainable innovation and commercial scalability. [Display omitted] [ABSTRACT FROM AUTHOR]

Experimental systems allowing aerosol exposure (AE) of cell cultures at the air-liquid-interface (ALI) are increasingly being used to assess the toxicity of inhaled contaminants as they are more biomimetic than standard methods using submerged cultures, however, they require detailed characterisation before use. An AE-ALI system combining aerosol generation with a CULTEX® exposure chamber was characterised with respect to particle deposition and the cellular effects of filtered air (typical control) exposures. The effect of system parameters (electrostatic precipitator voltage, air flowrate to cells and insert size) on deposition efficiency and spatial distribution were investigated using ICP-MS and laser ablation ICP-MS, for an aerosol of CeO 2 nanoparticles. Deposition varied with conditions, but appropriate choice of operating parameters produced broadly uniform deposition at suitable levels. The impact of air exposure duration on alveolar cells (A549) and primary small airway epithelial cells (SAECs) was explored with respect to LDH release and expression of selected genes. Results indicated that air exposures could have a significant impact on cells (e.g., cytotoxicity and expression of genes, including CXCL1, HMOX1, and SPP1) at relatively short durations (from 10 mins) and that SAECs were more sensitive. These findings indicate that detailed system characterisation is essential to ensure meaningful results. • Aerosol exposure at air-liquid-interface systems need characterisation before use. • Laser ablation ICP-MS can show the deposition pattern of metallic particle on cells. • Air-only control exposures can induce cytotoxicity and changes in gene expression. • LDH release and gene expression changes increase with flowrate and duration. • Small airway epithelial cells are more sensitive to air exposures than A549 cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The landscape of available SbD literature has been mapped. • SbD toolboxes relevant to SSbD have been identified. • There is a paucity of SbD and SSbD studies performing high-throughput screening. • It is necessary to better incorporate chemical and material functionality in SSbD. • Regular mapping of newly published SbD and SSbD literature is required. With the introduction of the European Commission's "Safe and Sustainable-by-Design" (SSbD) framework, the interest in understanding the implications of safety and sustainability assessments of chemicals, materials, and processes at early-innovation stages has skyrocketed. Our study focuses on the "Safe-by-Design" (SbD) approach from the nanomaterials sector, which predates the SSbD framework. In this assessment, SbD studies have been compiled and categorized into reviews, case studies, and frameworks. Reviews of SbD tools have been further classified as quantitative, qualitative, or toolboxes and repositories. We assessed the SbD case studies and classified them into three categories: safe(r)-by-modeling, safe(r)-by-selection, or safe(r)-by-redesign. This classification enabled us to understand past SbD work and subsequently use it to define future SSbD work so as to avoid confusion and possibilities of "SSbD-washing" (similar to greenwashing). Finally, the preexisting SbD frameworks have been studied and contextualized against the SSbD framework. Several key recommendations for SSbD based on our analysis can be made. Knowledge gained from existing approaches such as SbD, green and sustainable chemistry, and benign-by-design approaches needs to be preserved and effectively transferred to SSbD. Better incorporation of chemical and material functionality into the SSbD framework is required. The concept of lifecycle thinking and the stage-gate innovation model need to be reconciled for SSbD. The development of high-throughput screening models is critical for the operationalization of SSbD. We conclude that the rapid pace of both SbD and SSbD development necessitates a regular mapping of the newly published literature that is relevant to this field. [ABSTRACT FROM AUTHOR]

Abstract Autism spectrum disorder (ASD) has emerged as a major public health concern due to its fast-growing prevalence in recent decades. Environmental factors are thought to contribute substantially to the variance in ASD. Interest in environmental toxins as causes of ASD has arisen due to the high sensitivity of the developing human brain to toxic chemicals, particularly to dioxin and certain dioxin-like compounds (dioxins). As a group of typical persistent organic pollutants, dioxins have been found to exert adverse effects on human brain development. In this paper, we review the evidence for association of exposure to dioxins with neurodevelopmental abnormalities related to ASD based on both human epidemiological and animal studies. It has been documented that exposure to dioxins during critical developmental periods increased risk for ASD. This notion has been demonstrated in different populations exposed to high or background level of dioxins. Furthermore, the effects and mechanisms of action of dioxins relevant to the pathophysiology and pathogenesis of ASD are summarized, describing potential underlying mechanisms linking dioxin exposure with ASD onset. Further studies focusing on effects of prenatal/perinatal exposure to individual dioxin congeners or to mixtures of dioxins on ASD-associated behavioral and neurobiological consequences in animal models, and on the mechanisms of actions of dioxins, are needed in order to better understand how dioxin exposure might contribute to increased risk for ASD. Highlights • Human and animal studies indicate association of dioxin exposure with ASD. • Dioxin exposure is related to ASD pathophysiology. • Dioxin exposure is related to ASD pathogenesis. [ABSTRACT FROM AUTHOR]

The wide use of titanium dioxide nanoparticles (TiO 2 NPs) in industrial applications requires the investigation of their effects on human health. In this context, we investigated the effects of nanosized and bulk titania in two different crystalline forms (anatase and rutile) in vitro. By colony forming efficiency assay, a dose-dependent reduction of the clonogenic activity of Balb/3T3 mouse fibroblasts was detected in the presence of rutile, but not in the case of anatase NPs. Similarly, the cell transformation assay and the micronucleus test showed that rutile TiO 2 NPs were able to induce type-III foci formation in Balb/3T3 cells and appeared to be slightly genotoxic, whereas anatase TiO 2 NPs did not induce any significant neoplastic or genotoxic effect. Additionally, we investigated the interaction of TiO 2 NPs with Balb/3T3 cells and quantified the in vitro uptake of titania using mass spectrometry. Results showed that the internalization was independent of the crystalline form of TiO 2 NPs but size-dependent, as nano-titania were taken up more than their respective bulk materials. In conclusion, we demonstrated that the cytotoxic, neoplastic and genotoxic effects triggered in Balb/3T3 cells by TiO 2 NPs depend on the crystalline form of the nanomaterial, whereas the internalization is regulated by the particle size. [ABSTRACT FROM AUTHOR]

Magmatic sources may contribute a significant amount of volatiles in geothermal springs; however, their role is poorly understood in submarine hydrothermal systems worldwide. In this study, new results of B and δ 11 B in 41 hydrothermal vent waters collected from the shallow hydrothermal system of Milos island in the Aegean Sea were combined with previously published data from other tectonic settings and laboratory experiments to quantify the effects of phase separation, fluid/sediment interaction and magmatic contribution. Two Cl-extreme solutions were identified, high-Cl waters (Cl as high as 2000 mM) and low-Cl waters (Cl < 80 mM). Both sets of waters were characterized by high B/Cl (~ 1.2–5.3 × 10 − 3 mol/mol) and extremely low δ 11 B (1.4–6.3‰), except for the waters with Mg content of near the seawater value and δ 11 B = 10.3–17.4‰. These high-Cl waters with high B/Cl and low δ 11 B plot close to the vent waters in sediment-hosted hydrothermal system (i.e., Okinawa Trough) or fumarole condensates from on-land volcanoes, implying B addition from sediment or magmatic fluids plays an important role. This is in agreement with fluid/sediment interactions resulting in the observed B and δ 11 B, as well as previously reported Br/I/Cl ratios, supporting a scenario of slab-derived fluid addition with elevated B, 11 B-rich, and low Br/Cl and I/Cl, which is derived from the dehydration of subducted-sediments. The slab fluid becomes subsequently mixed with the parent magma of Milos. The deep brine reservoir is partially affected by injections of magmatic fluid/gases during degassing. The results presented here are crucial for deciphering the evolution of the brine reservoirs involved in phase separation, fluid/sediment interaction and magmatic contribution in the deep reaction zone of the Milos hydrothermal system; they also have implications in the understanding of the formation of metallic vein mineralization. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotube (MWCNT) length is suggested to critically determine their pulmonary toxicity. This stems from in vitro and in vivo rodent studies and in vitro human studies using cell lines (typically cancerous). There is little data using primary human lung cells. We addressed this knowledge gap, using highly relevant, primary human alveolar cell models exposed to precisely synthesised and thoroughly characterised MWCNTs. In this work, transformed human alveolar type-I-like epithelial cells (TT1), primary human alveolar type-II epithelial cells (ATII) and alveolar macrophages (AM) were treated with increasing concentrations of MWCNTs before measuring cytotoxicity, inflammatory mediator release and MAP kinase signalling. Strikingly, we observed that short MWCNTs (~0.6µm in length) induced significantly greater responses from the epithelial cells, whilst AM were particularly susceptible to long MWCNTs (~20µm). These differences in the pattern of mediator release were associated with alternative profiles of JNK, p38 and ERK1/2 MAP kinase signal transduction within each cell type. This study, using highly relevant target human alveolar cells and well defined and characterised MWCNTs, shows marked cellular responses to the MWCNTs that vary according to the target cell type, as well as the aspect ratio of the MWCNT. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biphasic depuration of Au NPs ingested by D. magna with ∼75% lost in 1h. [•] Au NPs imaged in the midgut close to the peritrophic membrane at 1 and 24h. [•] No images of Au NP uptake at the microvilli. As also shown for CNTs and CuO NPs. [•] Au NPs retained in the lumen, but not internalized into the gut epithelial cells. [•] In daphnia in vivo retention of NPs does not necessarily equate to internalization. [ABSTRACT FROM AUTHOR]

Highlights: [•] In natural seawater media a noticeable fraction of CdS remained in the nanoscale. [•] Worms accumulated Cd in both soluble Cd and CdS NPs in waterborne exposures. [•] Greater biochemical responses in worms exposed to CdS NPs in seawater compared to CdS contaminated food. [•] Biochemical oxidative processes are the main consequences of exposure to Cd NPs. [ABSTRACT FROM AUTHOR]

Abstract: The increasing use of nano-sized materials in our environment, and in many consumer products, dictates new safety concerns. In particular, adequate experimental models are needed to evaluate skin toxicity of metal oxide ions, commonly found in cosmetic and dermatologic preparations. We have addressed the biological effects of topically applied copper oxide (CuO) nanoparticles in human skin organ cultures, using light and electron microscopy, and biochemical tests. Nanoparticles were more toxic than micro-sized particles, and their effects were stronger when supplied in growth medium than in topical application. Still topically applied CuO nanoparticles induced inflammatory cytokine secretion and necrosis, especially in epidermis deprived of its protective cornea. Since nanoparticle penetration was not seen, we propose that they may adhere to skin surface, react with the local acidic environment, and generate soluble ions that make their way to inner sites. This work illustrates the abilities of skin organ culture to evaluate the biological effects of topically-applied materials on skin in vitro. [Copyright &y& Elsevier]

Abstract: Engineered nano-sized Cu oxide particles are extensively used in diverse applications. Because aquatic environments are the ultimate “sink” for all contaminants, it is expected that nanoparticles (NP) will follow the same fate. In this study, two marine invertebrates Scrobicularia plana and Hediste diversicolor were chosen as ecotoxicological models. The aim was to evaluate behavioural (burrowing kinetics, feeding rate) and biochemical (biomarkers) responses of S. plana and H. diversicolor exposed in the laboratory to Cu (10μgL−1) added in natural seawater either in the form of engineered nanoparticles (NPs) of CuO or as dissolved Cu in 2% HNO3. Exposure was characterized by considering (i) the physico-chemical fate of NP (ii) the fraction of labile Cu in experimental media and (iii) Cu bioaccumulation. Results showed high aggregation of CuO NPs in seawater and no additional bioavailable Cu concentrations. Behavioural impairments were observed in S. plana exposed to CuO NPs or soluble Cu whereas in H. diversicolor, only the exposure to soluble Cu led to a burrowing decrease. No obvious neurotoxicity effects were revealed since in both species, no changes in cholinesterasic activity occurred in response to both forms of Cu exposure. Biomarkers of oxidative-stress catalase and glutathione-S-transferase were enhanced in both species whereas superoxide dismutase was increased only in S. plana exposed to CuO NPs. Metallothionein-like protein was increased in bivalves exposed to both forms of Cu. Since, no detectable release of soluble Cu from CuO NPs occurred during the time of experiment, ecotoxicity effects seem to be related to CuO NPs themselves. [Copyright &y& Elsevier]

Using laser Raman microprobe spectroscopy, we have characterized the degree of hydroxylation and the state of atomic order of several natural and synthetic calcium phosphate phases, including apatite of biological (human bone, heated human bone, mouse bone, human and boar dentin, and human and boar enamel), geological, and synthetic origin. Common belief holds that all the studied phases are hydroxylapatite, i.e., an OH-containing mineral with the composition Ca10(PO4)6(OH)2. We observe, however, that OH-incorporation into the apatite crystal lattice is reduced for nanocrystalline samples. Among the biological samples, no OH-band was detected in the Raman spectrum of bone (the most nanocrystalline biological apatite), whereas a weak OH-band occurs in dentin and a strong OH-band in tooth enamel. We agree with others, who used NMR, IR spectroscopy, and inelastic neutron scattering, that—contrary to the general medical nomenclature—bone apatite is not hydroxylated and therefore not hydroxylapatite. Crystallographically, this observation is unexpected; it therefore remains unclear what atom(s) occupy the OH-site and how charge balance is maintained within the crystal. For non-bone apatites that do show an OH-band in their Raman spectra, there is a strong correlation between the concentration of hydroxyl groups (based on the ratio of the areas of the 3572 Δcm−1 OH-peak to the 960 Δcm−1 P–O phosphate peak) and the crystallographic degree of atomic order (based on the relative width of the 960 Δcm−1 P–O phosphate peak) of the samples. We hypothesize that the body biochemically imposes a specific state of atomic order and crystallinity (and, thus, concentration of hydroxyl) on its different apatite precipitates (bone, dentin, enamel) in order to enhance their ability to carry out tissue-specific functions. [Copyright &y& Elsevier]

• Intranasal exposure to ZnO NPs induced accumulation of Zn in liver of rat. • No accumulation of Zn in liver was found in ZnSO 4 treatment. • Persistence of NPs in liver 7 days post exposure was revealed by XAFS. • More and distinct metabolites in liver were altered by ZnO NPs than by ZnSO 4. • ZnO NPs induced particle-specific effects revealed by metabolomics. Toxicity of ZnO nanoparticles (NPs) are often related to the release of Zn2+ ions due to their dissolution. Studies also suggest that the toxicity of ZnO NPs cannot be solely explained by the release of Zn2+ ions; however, there is a lack of direct evidence of ZnO particulate effects. This study compared the acute toxicity of ZnO NPs and ZnSO 4 following intranasal exposure using a combination of metallomics and metabolomics approaches. Significant accumulation of Zn in the liver was only found in the ZnO NP treatment, with 29% of the newly accumulated Zn in the form of ZnO as revealed by X-ray fine structure spectroscopy (XAFS). This is the first direct evidence suggesting the persistence of ZnO NPs in liver upon intranasal exposure. Although both ZnO NPs and ZnSO 4 altered the metabolite profiles, with some overlaps and considerable specificity, of both liver and plasma samples, more and distinct metabolites in the liver and opposite effects in the plasma were altered by ZnO NPs compared with ZnSO 4 , consistent with no accumulation of Zn detected in liver from ZnSO 4. Specifically, a large number of antioxidant-related compounds and energetic substrates were exclusively elevated in the liver of ZnO NP-treated animals. These findings provided direct evidence that persistence of ZnO NPs induced particle-specific effects on the antioxidant systems and energy metabolism pathways. [ABSTRACT FROM AUTHOR]