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1.
J Hazard Mater ; 416: 126043, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492890

RESUMO

The transformation of Ag+ is strongly correlated with its risks in aquatic environment. Considering the wide application of molybdenum disulfide (MoS2) and the inevitable release into the environment, the effects of MoS2 on Ag+ transformation and toxicity are of great concerns. This study revealed the pH-dependent reduction of Ag+ (0.5 mM) to Ag nanoparticles (AgNPs) by MoS2 (50 mg/L) and solar irradiation obviously accelerates the AgNPs formation (2.638 mg/L per day, pH=7.0) compared with dark condition (0.637 mg/L per day), ascribing to the electrons capture from electron-hole pairs of MoS2 by Ag+. Ionic strengths and natural organic matter decreased the AgNPs yield. Metallic 1 T phase of MoS2 primarily participated in AgNPs formation and was oxidized to soluble ions (MoO42-) due to the oxygen generation in valance band. The above processes also occurred between Ag+ and MoS2 at environmentally relevant concentrations. Further, photoinduced transformation of Ag+ by MoS2 (10-100 µg/L) significantly lowered its toxicity to freshwater algae. The AgNPs formation on MoS2 reduced the bioavailability of Ag+ to algae, which was the mechanism for attenuated Ag+ toxicity. The provided data are helpful for better understanding the roles of MoS2 on the environmental fates and risks of metal ions under natural conditions.


Assuntos
Nanopartículas Metálicas , Prata , Dissulfetos , Água Doce , Íons , Nanopartículas Metálicas/toxicidade , Molibdênio/toxicidade , Prata/toxicidade
2.
Water Res ; 204: 117603, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536684

RESUMO

Determining the bioavailability and toxicity mechanism of silver nanoparticles (AgNPs) is challenging as Ag+ is continuously released by external or internal AgNP dissolution in the actual exposure system (regardless of the laboratory or the natural environment). Here a novel pulsed-gradient Ag+ (AgNO3) exposure was conducted with zebrafish (Danio rerio) larvae to simulate dissolved gradient concentrations of Ag+ from polyvinylpyrrolidone (PVP)-coated AgNPs. The accumulation and toxicity of the pulsed-gradient Ag+ (AgNO3) and, in the meantime, the released Ag+ from PVP-AgNPs were predicted using a toxicokinetic-toxicodynamic (TK-TD) model with obtained Ag+ parameters. In order to further understand the possible mechanism of PVP-AgNP releasing Ag+ in the body, subcellular fractions (S9) of zebrafish were also used to incubate with AgNPs in vitro to mimic the realistic in vivo scenarios. In the TK process, in vivo analysis showed that AgNPs released around twice as many Ag+ into the body than were detected with a single Ag+ pulse-exposure system; this was supported by evidence that subcellular S9 fractions might cause the PVP-AgNPs to lose the capping agent and favor Ag+ release. In the TD process, toxicity (survival rate) was predicted by the total bodily Ag(I) concentration, suggesting that AgNP toxicity in larvae was mainly due to gradually released Ag+ rather than AgNPs themselves. This study helps clarify the role of Ag+ in AgNP toxicity and offers a novel framework by which to investigate the toxicity of metal nanoparticles and corresponding metal ions in biological systems.


Assuntos
Nanopartículas Metálicas , Prata , Animais , Disponibilidade Biológica , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Toxicocinética , Peixe-Zebra
3.
J Environ Manage ; 297: 113434, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34400389

RESUMO

The development of environmentally friendly new procedures for the synthesis of metallic nanoparticles is one of the main goals of nanotechnology. Proteins and enzymes from plants, filamentous fungi, yeast, and bacteria to produce nanoparticles are both valuable and viable alternatives to conventional synthesis of nanomaterials due to their high efficiency and the low cost to scale up and generate large quantities. The aim of this work is to compare biogenic silver nanoparticles (AgNPs) obtained from cell-free filtrates from the fungus Macrophomina phaseolina to conventional chemical AgNPs, in biocidal activity and toxicity. Our results show that bio-AgNPs displayed similar bactericidal activity than chemical AgNPs, but less toxicity in the model organism Caenorhabditis elegans. We employed biochemical and proteomic techniques to profile the unique surface chemistry of the capping in the bio-AgNPs and therefore to identify the proteins involved in their synthesis and stability. These results not only suggest that the proteins involved in the synthesis of the nanoparticles and corona formation in the bio-AgNPs are responsible for keeping the silver core preserved making them more stable in time, but also masking and protecting eukaryotic cells from metal toxicity.


Assuntos
Nanopartículas Metálicas , Coroa de Proteína , Ascomicetos , Nanopartículas Metálicas/toxicidade , Proteômica , Prata/toxicidade
4.
Environ Pollut ; 286: 117571, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34438494

RESUMO

Silver nanomaterials (AgNMs) are broadly used and among the most studied nanomaterials. The underlying molecular mechanisms (e.g. protein and metabolite response) that precede phenotypical effects have been assessed to a much lesser extent. In this paper, we assess differentially expressed proteins (DEPs) and metabolites (DEMs) by high-throughput (HTP) techniques (HPLC-MS/MS with tandem mass tags, reversed-phase (RP) and hydrophilic interaction liquid chromatography (HILIC) with mass spectrometric detection). In a time series (0, 7, 14 days), the standard soil model Enchytraeus crypticus was exposed to AgNM300K and AgNO3 at the reproduction EC20 and EC50. The impact on proteins/metabolites was clearly larger after 14 days. NM300K caused more upregulated DEPs/DEMs, more so at the EC20, whereas AgNO3 caused a dose response increase of DEPs/DEMs. Similar pathways were activated, although often via opposite regulation (up vs down) of DEPs, hence, dissimilar mechanisms underlie the apical observed impact. Affected pathways included e.g. energy and lipid metabolism and oxidative stress. Uniquely affected by AgNO3 was catalase, malate dehydrogenase and ATP-citrate synthase, and heat shock proteins (HSP70) and ferritin were affected by AgNM300K. The gene expression-based data in Adverse Outcome Pathway was confirmed and additional key events added, e.g. regulation of catalase and heat shock proteins were confirmed to be included. Finally, we observed (as we have seen before) that lower concentration of the NM caused higher biological impact. Data was deposited to ProteomeXchange, identifier PXD024444.


Assuntos
Nanopartículas Metálicas , Nanoestruturas , Poluentes do Solo , Íons , Metabolômica , Nanopartículas Metálicas/toxicidade , Nanoestruturas/toxicidade , Proteômica , Prata/toxicidade , Poluentes do Solo/análise , Espectrometria de Massas em Tandem , Transcriptoma
5.
Artigo em Inglês | MEDLINE | ID: mdl-34444111

RESUMO

Metal nanoparticles are used in various branches of industry due to their physicochemical properties. However, with intensive use, most of the waste and by-products from industries and household items, and from weathering of products containing nanoparticles, end up in the waters. These pollutants pose a risk to aquatic organisms, one of which is a change in the expression of various genes. Most of the data that focus on metal nanoparticles and their effects on aquatic organisms are about copper and silver nanoparticles, which is due to their popularity in general industry, but information about other nanoparticulate metals can also be found. This review aims to evaluate gene expression patterns in aquatic organisms by metal nanoparticles, specifying details about the transcription changes of singular genes and, if possible, comparing the changes in the expression of the same genes in different organisms. To achieve this goal, available publications tackling this problem are studied and summarized. Nanometals were found to have a modulatory effect on gene expression in different aquatic organisms. Data show both up-regulation and down-regulation of genes. Nano silver, nano copper, and nano zinc show a regulatory effect on genes involved in inflammation and apoptosis, cell cycle regulation and ROS defense as well as in general stress response and have a negative effect on the expression of genes involved in development. Nano gold, nano titanium, nano zinc, and nano iron tend to elevate the transcripts of genes involved in response to ROS, but also pro-apoptotic genes and down-regulate DNA repair-involved genes and anti-apoptotic-involved genes. Nano selenium showed a rare effect that is protective against harmful effects of other nanoparticles, but also induced up-regulation of stress response genes. This review focuses only on the effects of metal nanoparticles on the expression of various genes of aquatic organisms from different taxonomic groups.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Óxido de Zinco , Organismos Aquáticos , Expressão Gênica , Nanopartículas Metálicas/toxicidade , Prata/toxicidade
6.
Brain Behav ; 11(8): e2319, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34333877

RESUMO

INTRODUCTION: Today, due to the increasing application of silver nanoparticles in medical products, it is necessary to pay attention to the user's safety. There are three methods, namely, chemical, physical, and biological, used for the production of nanoparticles. Although the first two methods might introduce health hazards, the latter is hypothetically safe. In this study, we examined the histopathological changes in the cerebellum of neonatal Wistar rats induced by injection of toxic and nontoxic doses of silver nanoparticles, which were produced by green synthetic method and were compared with chemical silver nanoparticles. METHODS: This study was a laboratory interventional study performed on 25 Wistar rats in the Animal Laboratory of Islamic Azad University of Shahrood. These rats were divided into five groups of the control group, the group with nonpoisonous injection of chemical nanoparticles, the group with nonpoisonous injection of biological nanoparticles, the group with injection of poisonous chemical nanoparticles, and the group with injection of poisonous biological nanoparticles. The rats were impregnated by the males of the same race and the cerebellum of their offspring was studied after birth. RESULTS: We found that the injection of nonpoisonous chemical nanoparticles caused hyperemia, inappropriate size, and dark cytoplasm in some Purkinje cells. Also, injection of poisonous chemical nanoparticles caused hyperemia and cellular dispersion in the molecular layer, caused abnormal shapes, and reduced the number of cells in Purkinje cells. However, injection of poisonous and nonpoisonous biological nanoparticles did not alter cerebellum cells nor did it cause any inflammation or hyperemia. CONCLUSION: In contrast with chemical nanoparticles, biological nanoparticles have less significant effect on the cerebellum cells.


Assuntos
Nanopartículas Metálicas , Prata , Animais , Cerebelo , Masculino , Nanopartículas Metálicas/toxicidade , Ratos , Ratos Wistar , Prata/toxicidade
7.
Ecotoxicol Environ Saf ; 222: 112548, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34325196

RESUMO

Studies have shown silver nanoparticles (AgNPs) exposure can result in a series of toxic effects in fish gills. However, it is still unclear how AgNPs affect metabolite expression and their related molecular metabolic pathways in fish gills. In this study, we employed untargeted metabolomics to study the effects of AgNPs and silver supernatant ions on fish gill metabolites. The results showed that AgNPs can induce significant changes in 96 differentially expressed metabolites, which mainly affect amino acid metabolism and energy metabolism in fish gills. Among these metabolites, AgNPs specifically induce significant changes in 72 differentially expressed metabolites, including L-histidine, L-isoleucine, L-phenylalanine, and citric acid. These metabolites were significantly enriched in the pathways of aminoacyl-tRNA biosynthesis, ABC transporters, and the citrate cycle. In contrast, Ag+ supernatant exposure can specifically induce significant changes in 14 differentially expressed metabolites that mainly interfere with sphingolipid metabolism in fish gills. These specifically regulated fish gill metabolites include sphinganine, sphingosine, and phytosphingosine, which were significantly enriched in the sphingolipid metabolism pathway. Our results clearly reveal the effects and potential toxicity mechanisms of AgNPs on fish gill metabolites. Furthermore, our study further determined the unique functions of released silver ions in AgNPs toxicity in fish gills.


Assuntos
Carpas , Nanopartículas Metálicas , Animais , Brânquias , Metabolômica , Nanopartículas Metálicas/toxicidade , Prata/toxicidade
8.
Sci Total Environ ; 794: 148765, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34225149

RESUMO

Nanoparticles released into the environment are attracting increasing concern because of their potential toxic effects. Conventional methods for assessing the toxicity of nanoparticles are usually confined to cultivable cells, but not applicable to viable but non-culturable (VBNC) cells. However, it remains unknown whether silver nanoparticles (AgNPs), a typical antimicrobial agent, could induce bacteria into a VBNC state in natural environments. In this work, the viability of E. coli, an indicator bacterium widely used for assessing the antibacterial activity of AgNPs, was examined through coupling plate counting, fluorescence staining and adenosine triphosphate (ATP) production. AgNPs were found to have a considerable antibacterial ability, which resulted in less than 0.0004% of culturable cells on plates. However, more than 80% of the cells still maintained their cell membrane integrity under the stress of 80 mg/L AgNPs. Meanwhile, the residue of ATP production (0.6%) was 1500 times higher than that of the culturable cells (< 0.0004%). These results clearly demonstrate that when exposed to AgNPs, most of cells fell into a VBNC state, instead of dying. Environmental factors, e.g., Cl- and illumination, which could change the dissolution, hydrophilicity and zeta potential of AgNPs, eventually influenced the culturability of E. coli. Inhibition of dissolved Ag+ and reactive oxygen species was found to facilitate the mitigation of the strain into a VBNC state. Our findings suggest the necessity of re-evaluating the environmental effects and antibacterial activities of AgNPs.


Assuntos
Escherichia coli , Nanopartículas Metálicas , Antibacterianos/toxicidade , Sobrevivência Celular , Nanopartículas Metálicas/toxicidade , Prata/toxicidade
9.
Sci Total Environ ; 796: 148843, 2021 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-34280635

RESUMO

The global environment annually receives thousands of tons of engineered nanomaterials (ENMs, particles less than 100 nm diameter). These particles have high active surface area, unique chemical properties, and can enter cells. Humanity uses many ENMs for their biological reactivity (e.g. microbicides), but their environmental effects are complex. We cataloged 2102 experimental results on whole organisms for 22 particle classes (mainly on Ag, Zn, Ti, and Cu) to assess biological responses, effective and lethal concentrations, and bioaccumulation of ENMs. Most responses were negative and varied significantly by particle type, functional group of organism, and type of response. Smaller particles tended to be more toxic. Aquatic organisms responded more negatively than did terrestrial organisms. Animals generally were most sensitive and plants least. Silver ENMs generally had the strongest negative effects. Effective and lethal concentrations generally exceeded modeled environmentally relevant concentrations and organisms usually did not accumulate or biomagnify to concentrations above those in their environment. However, most experiments lasted less than a week and were not field studies. Research to date is probably insufficient to understand chronic effects and long-term biomagnification. Numerous unique and untested ENMs continue to enter environments at accelerating rates, and our analysis indicates potential for negative effects. Our data suggest substantial research is still required to understand the ultimate influence of ENMs as they continue to accumulate in the environment. Around 40% of the papers with experimental data for ENMs failed with respect to reporting means, sample sizes, or experimental error, or they did not have proper experimental design (e.g. lack of true controls). We need more high-quality experiments that are more realistic (field or mesocosm), longer duration, contain a wider range of organisms, and account for complex food web structure.


Assuntos
Nanoestruturas , Animais , Cadeia Alimentar , Nanoestruturas/toxicidade , Plantas , Prata/toxicidade
10.
Nanoscale ; 13(28): 12356-12369, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34254625

RESUMO

Previous studies have revealed that the liver is the main target organ of deposition for engineered nanoparticles. The hepatotoxicity of silver nanoparticles (AgNPs), the widely used antimicrobial nanoparticles, has been of great interest. However, little is known about the regulatory mechanism of the mitochondria in AgNP-induced hepatotoxicity. In the present study, we found that AgNPs, rather than silver ions, induced mitochondrial dynamics disorders, oxidative stress, and mitochondria-dependent hepatocyte apoptosis in mice. Using human hepatocellular carcinoma (HepG2) cells, we confirmed that the interaction between dynamin-related protein 1 (DRP1)-dependent mitochondrial fission and oxidative stress promoted mitochondrial damage and mitochondria-dependent apoptosis induced by AgNPs, as determined by the elimination of DRP1 or addition of N-acetylcysteine (NAC). Interestingly, the crosstalk between DRP1-dependent mitochondrial fission and oxidative stress also activated mitophagy and autophagy flux blocking. Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1) gene silencing contributed to the aggravation of mitochondrial damage, oxidative stress, and apoptosis. These results revealed that the interplay between mitochondrial fission and oxidative stress induced mitophagy defects and triggered AgNP-induced mitochondria-dependent apoptosis in liver cells both in vivo and in vitro. Our findings provide a perspective for the mechanism of hepatotoxicity induced by exposure to metal NPs.


Assuntos
Nanopartículas Metálicas , Dinâmica Mitocondrial , Animais , Apoptose , Dinaminas/metabolismo , Hepatócitos/metabolismo , Nanopartículas Metálicas/toxicidade , Camundongos , Estresse Oxidativo , Prata/toxicidade
11.
J Hazard Mater ; 418: 126368, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34329024

RESUMO

Sediments represent the major sink for released silver nanoparticles (AgNPs) in aquatic environments. It is well known that the environmental behavior and toxicity of AgNPs in sediments are governed by their specific chemical species instead of their total concentration. This review focuses on various chemical transformations of AgNPs in sediments, which have not been well outlined before. We first outline the concentrations of AgNPs in sediments. The predicted concentrations are 1-5 µg kg-1 in most model studies. Once enter sediments, AgNPs are transformed to different species (e.g., Ag2S, Ag-humic substance complexes, AgCl, and Ag+) during multiple chemical transformations, such as oxidative dissolution, sulfidation, chlorination, and complexation. Those chemical behaviors mitigate the toxicity of AgNPs by reducing their availability and decreasing Ag+ release. Benthic invertebrates and microbes are prone to be affected by AgNPs. AgNPs are found to be accumulated in sediment-dwelling organisms and transferred to higher trophic levels along the food web. Besides X-ray absorption spectroscopy, reliable separation procedures coupled with detection techniques, are powerful tools that characterize the speciation of AgNPs in sediments. More research is needed to investigate diverse chemical transformations in various sediments through development of novel techniques and mathematical models.


Assuntos
Nanopartículas Metálicas , Poluentes Químicos da Água , Sedimentos Geológicos , Nanopartículas Metálicas/toxicidade , Modelos Teóricos , Prata/análise , Prata/toxicidade , Poluentes Químicos da Água/toxicidade
12.
Sci Total Environ ; 797: 149200, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34303973

RESUMO

Silver nanoparticles (AgNPs) are one of the most commonly used nanomaterials in industrial and agricultural production. Glyphosate is a broad-spectrum systemic herbicide, which mainly acts in the phloem of weeds that compete with crop growth and is widely used in agriculture. This study investigated the interactive effects of AgNPs and glyphosate on the physiological morphology, gene transcription, and rhizosphere microorganisms of wheat. Our results demonstrated that wheat growth, and the structure and diversity of rhizosphere microorganisms were slightly influenced by AgNPs and glyphosate single treatment at the test concentration. However, AgNPs and glyphosate (Gly) combined treatment (AgNPs + Gly) strongly inhibited wheat growth and influenced gene transcription. In total, 955, 601, and 1336 genes were determined to be differentially expressed in AgNPs, glyphosate, and combined treatment, respectively. According to KEGG analysis, the combined groups induced an antioxidant response by upregulating the transcription of phenylpropanoid biosynthesis-related genes. In addition, more energy was needed, and disrupted cell membrane was shown in the combined treatment, which displayed in the upregulation of sucrose, starch, and lipid synthesis. Moreover, the relative abundance of Bradyrhizobium, Devosia, Kribbella, Sphingopyxis (nitrogen-fixing bacteria), and Streptomyces (plant growth-promoting bacteria) in soil microbiota were decreased, implicated that nitrogen fixation and some beneficial substance secretions were inhibited by the combined treatment. This study emphasized that the synergetic effects of AgNPs and glyphosate exerted a negative impact on wheat growth.


Assuntos
Nanopartículas Metálicas , Prata , Glicina/análogos & derivados , Nanopartículas Metálicas/toxicidade , Rizosfera , Prata/toxicidade , Microbiologia do Solo , Triticum
13.
Chemosphere ; 283: 131164, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34144291

RESUMO

Limited studies of quantitative toxicity-toxicity relationship (QTTR) modeling have been conducted to predict interspecies toxicity of engineered nanomaterials (ENMs) between aquatic test species. A meta-analysis of 66 publications providing acute toxicity data of silver nanoparticles (AgNPs) to daphnia and fish was performed, and the toxicity data, physicochemical properties, and experimental conditions were collected and curated. Based on Euclidean distance (ED) grouping, a meaningful correlation of logarithmic lethal concentrations between daphnia and fish was derived for bare (R2bare = 0.47) and coated AgNPs (R2coated = 0.48) when a distance of 10 was applied. The correlation of coated AgNPs was improved (R2coated = 0.55) by the inclusion of descriptors of the coating materials. The correlations were further improved by R2bare = 0.57 and R2coated = 0.81 after additionally considering particle size only, and by R2bare = 0.59 and R2coated = 0.92 after considering particle size and zeta potential simultaneously. The developed ED-based nano-QTTR model demonstrated that inclusion of the coating material descriptors and physicochemical properties improved the goodness-of-fit to predict interspecies aquatic toxicity of AgNPs between daphnia and fish. This study provides insight for future in silico research on QTTR model development in ENM toxicology.


Assuntos
Daphnia , Nanopartículas Metálicas , Animais , Nanopartículas Metálicas/toxicidade , Tamanho da Partícula , Prata/toxicidade , Nitrato de Prata
14.
Aquat Toxicol ; 237: 105869, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34082272

RESUMO

Silver nanoparticles (Ag NPs) are widely used in consumer products especially because of their antimicrobial properties. However, this wide usage of Ag NPs is accompanied by their release into the environment where they will be rapidly transformed to other silver species - especially silver sulfide (Ag2S). In the present study, we synthesized Ag NPs and sulfidized them to obtain a core-shell system Ag@Ag2S NPs. Both types of particles form stable dispersions with hydrodynamic diameters of less than 100 nm when diluted in water, but tend to form micrometer-sized agglomerates in biological exposure media. Application of Ag and Ag@Ag2S NPs to rainbow trout intestinal cells (RTgutGC) resulted in a concentration-dependent cytotoxicity for both types of particles, as assessed by a three-endpoint assay for metabolic activity, membrane integrity and lysosomal integrity. The Ag NPs were shown to be slightly more toxic than the Ag@Ag2S NPs. Adding Ag or Ag@Ag2S NPs to RTgutGC cells, grown on a permeable membrane to mimic the intestinal barrier, revealed considerable accumulation of silver for both types of particles. Indeed, the cells significantly attenuated the NP translocation, allowing only a fraction of the metal to translocate across the intestinal epithelium. These findings support the notion that the intestine constitutes an important sink for Ag NPs and that, despite the reduced cytotoxicity of a sulfidized NP form, the particles can enter fish where they may constitute a long-term source for silver ion release and cytotoxicity.


Assuntos
Nanopartículas Metálicas , Oncorhynchus mykiss , Poluentes Químicos da Água , Animais , Intestinos , Nanopartículas Metálicas/toxicidade , Prata/análise , Prata/toxicidade , Compostos de Prata , Poluentes Químicos da Água/toxicidade
15.
Aquat Toxicol ; 237: 105895, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34147820

RESUMO

Toxic effects of silver nanoparticles (AgNPs) on fish gills have been widely reported but the recoverability of AgNPs-induced fish gill injuries is still unknown. In this study, combined multiomics and conventional toxicological analytical methods were used to investigate the changes in the gills of common carp responses to AgNPs (0.1 mg/L) toxicity after 24 h exposure and 7-day recovery. Conventional toxicological results showed that AgNPs exposure significantly increased silver content in gills and caused epithelial hyperplasia and lamellar fusion. After the recovery period, the silver content in fish gills significantly decreased; accompanied by the disappearance of histopathological characteristics in fish gills. Multiomics results revealed that AgNPs exposure resulted in the differential expression of 687 genes and 96 metabolites in fish gills. These differentially expressed genes (DEGs) and metabolites mainly participate in amino acid, carbohydrate, and lipid metabolisms, and are significantly enriched in the tricarboxylic acid (TCA) cycle. After the recovery period, the number of DEGs and metabolites in gills decreased to 33 and 90, respectively. Moreover, DEGs and metabolites in the TCA cycle recovered to control levels. In summary, the present study found that AgNPs-induced fish gill toxicity showed potential recoverability at molecular and phenotype levels.


Assuntos
Carpas , Nanopartículas Metálicas , Poluentes Químicos da Água , Animais , Brânquias/química , Metabolômica , Nanopartículas Metálicas/toxicidade , Prata/análise , Prata/toxicidade , Transcriptoma , Poluentes Químicos da Água/toxicidade
16.
Part Fibre Toxicol ; 18(1): 23, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34134756

RESUMO

BACKGROUND: Widespread use of silver in its different forms raises concerns about potential adverse effects after ingestion, the main exposure route for humans. The aim of this study was to investigate in CD-1 (ICR) male mice the tissue distribution and in vivo effects of 4-week oral exposure to 0.25 and 1 mg Ag/kg bw 10 nm citrate coated silver nanoparticles (AgNPs) and 1 mg Ag/kg bw silver acetate (AgAc) at the end of treatment (EoT) and after 4 weeks of recovery. RESULTS: There were no treatment-related clinical signs and mortality, and no significant effects on body and organ weights at the EoT and after recovery. Treatment-related changes in hematology and clinical chemistry were found after recovery, the most relevant being a dose-dependent lymphopenia and increased triglycerides in AgNP-treated mice, and increased levels of urea in all treated groups, associated with decreased albumin only in AgAc-treated mice. At the EoT the highest silver concentration determined by Triple Quadrupole ICP-MS analysis was found in the brain, followed by testis, liver, and spleen; much lower concentrations were present in the small intestine and kidney. Tissue silver concentrations were slightly higher after exposure to AgAc than AgNPs and dose dependent for AgNPs. After recovery silver was still present in the brain and testis, highlighting slow elimination. No histopathological changes and absence of silver staining by autometallography were observed in the organs of treated mice. At the EoT GFAP (astrocytes) immunoreactivity was significantly increased in the hippocampus of AgNP-treated mice in a dose-dependent manner and Iba1 (microglial cells) immunoreactivity was significantly increased in the cortex of 1 mg/kg bw AgNP-treated mice. After recovery, a significant reduction of Iba1 was observed in the cortex of all treated groups. TEM analysis of the hippocampus revealed splitting of basement membrane of the capillaries and swelling of astrocytic perivascular end-feet in 1 mg/kg bw AgNP- and AgAc-treated mice at the EoT. CONCLUSIONS: Our study revealed accumulation and slow clearance of silver in the brain after oral administration of 10 nm AgNPs and AgAc at low doses in mice, associated with effects on glial cells and ultrastructural alterations of the Blood-Brain Barrier.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Administração Oral , Animais , Encéfalo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Distribuição Tecidual
17.
Chemosphere ; 280: 130863, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34162100

RESUMO

The potential effects of extracellular polymeric substances (EPS) on the behavior and toxicity of silver nanoparticle (Ag-NPs) and silver sulfide nanoparticle (Ag2S-NPs) remains ambiguous. The interaction of EPS from Bacillus subtilis with Ag2S-NPs, metallic Ag-NPs, or ionic Ag, and the associated plant safety had been examined in this study. The biological impacts of Ag-NPs and Ag2S-NPs were Ag form-dependent and highly influenced by microbial EPS. Compared with metallic Ag-NPs, Ag2S-NPs exert inert biological impacts, as revealed by 3.44 times lower Ag bioaccumulation in wheat (Triticum aestivum L.) seedlings and nearly reduce plant biomass when wheat was subjected to 1.0 mg-Ag L-1 of Ag-NPs and Ag2S-NPs with the transfer factors of 151.56-930.87 vs. 12.52-131.81, respectively. These observations were coincident with the low dissolved Ag ([Ag]diss) in the Ag2S-NPs treatment than the Ag-NPs treatment (114.0 vs. 0.0791, µg L-1). Compared with the enhanced toxicity of Ag2S-NPs to wheat, Bacillus subtilis EPS significantly alleviate the phytotoxicity of Ag-NPs, as revealed by the relative root elongation (7.15-45.40% decrease vs. 2.39-11.75% increase), and malondialdehyde (1.47-83.22% increase vs. 8.57-25.25% decrease) and H2O2 (11.27-71.78% increase vs. 5.16-36.67% decrease) contents. These constrasting plant responses of B. subtilis EPS are mainly caused by their complexation property with toxic Ag+ and nutrient elements for wheat stressed by Ag-NPs and Ag2S-NPs, respectively. Our findings highlight the importance of rhizospheric EPS in affecting the biogeochemistry and ecotoxicity of metal nanoparticles including Ag-NPs and Ag2S-NPs in agricultural systems.


Assuntos
Nanopartículas Metálicas , Prata , Bioacumulação , Matriz Extracelular de Substâncias Poliméricas , Peróxido de Hidrogênio , Nanopartículas Metálicas/toxicidade , Raízes de Plantas , Prata/toxicidade , Triticum
18.
J Hazard Mater ; 419: 126429, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34174620

RESUMO

Sunlight-oxidative ageing is a common and critical process for microplastics (MPs) in aquatic environments. O2•-, 1O2, and •OH generation has been widely proven in this process, which can alter metal speciation based on its reduction and oxidation potential. Herein, chemical speciation of Ag mediated by polystyrene (PS) MPs was determined under simulated sunlight irradiation. The O2•- generation on the PS MPs surfaces is the vital factor for Ag+ reduction, regardless of acid or base conditions. The 1O2 and •OH are dominant factors, and 1O2 played a more important role than •OH for its higher formation amount, causing oxidative dissolution of newly formed Ag0 nanoparticles (NPs). The Ag NPs can hetero-aggregate with PS MPs through electrostatic interactions with O-containing groups (C-O, C-OH and CO), and co-precipitate from the water phase. This hetero-aggregation can stabilize Ag NPs by inhibiting Ag NPs surface photooxidation and suppressing Ag+ release. Transformation of Ag species (from Ag+ to Ag0 NPs) mediated by sunlight with PS MPs significantly suppressed acute toxicity of Ag+ to Escherichia coli, Selenastrum capricornutum, Daphnia magna and zebrafish. This study emphasized that PS MPs play an important role in the speciation, migration and toxicity of Ag+ in freshwater environments.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Cinética , Plásticos , Poliestirenos/toxicidade , Prata/toxicidade , Luz Solar , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
19.
J Hazard Mater ; 418: 126316, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118550

RESUMO

Recently, nanomaterials synthesized ecologically using microorganisms have attracted much interest. In the present study, the ability of Gloeophyllum striatum to synthesize silver nanoparticles is described for the first time. Nanoparticles were formed in an eco-friendly extracellular manner and characterized by UV-Vis, FT-IR, MADLS and SEM techniques. The obtained nanoparticles showed excellent activity against gram-positive and gram-negative bacteria. The MIC values for gram-negative bacteria were 15 µM, while for gram-positive strains they reached 30 µM. The haemolytic and cytotoxic activities of the synthesized nanoparticles towards mammalian cells were also determined. The addition of AgNPs at the concentrations above 30 µM caused 50% haemolysis of red blood cells after they 24-hour incubation. A decrease in the viability of fibroblasts by over 50% was also found in the samples treated with nanoparticles at the concentrations above 30 µM. The ecotoxicological risk of silver nanoparticles was assessed using A. franciscana and D. magna crustaceans as well as L. sativum plants. The EC50 values for A. franciscana and D. magna were 61.97 and 0.275 µM, respectively. An about 20% reduction in the length of L. sativum shoots and roots was noted after the treatment with AgNPs at the concentration of 100 µM.


Assuntos
Nanopartículas Metálicas , Prata , Animais , Antibacterianos/toxicidade , Basidiomycota , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Nanopartículas Metálicas/toxicidade , Testes de Sensibilidade Microbiana , Medição de Risco , Prata/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Chemosphere ; 284: 131269, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34186226

RESUMO

Nanotoxicology research commonly utilizes pristine nanomaterials for toxicity assessment, which may not be perfectly representative of what is released into environmental systems. The goal of the present study was to develop a method to simulate human weathering of silver-containing textiles. To achieve this goal the roles of physical and chemical stress on X-Static® containing athletic textiles were investigated and compared to data collected from human weathering experiments and literature. Chemical weathering methods (artificial sweat) were used independently and alongside physical weathering methods (3D printed stretching and abrasion instruments). Non-weathered control textiles were found to release 29 ± 11 mg Ag/kg of textile into wash water effluent (ICP-MS), with 16% being released as ionic silver (ICP-MS) and the rest as metallic nanomaterials, nanosheets, and particulates of varying size (SEM/XANES). Real and simulated human weathered textiles released similar amounts of total silver (67 ± 11 mg Ag/kg, 84 ± 13 mg Ag/kg respectively) with the silver released being composed of ionic (1.5%, 2%) and a mixture of metallic and chlorinated nanomaterials, nanosheets, and particulates. The method was shown to effectively detach environmentally representative silver materials from silver-containing textiles and can provide such materials for future studies on the assessment of their fate, transport, and toxicity.


Assuntos
Nanopartículas Metálicas , Nanoestruturas , Humanos , Nanoestruturas/toxicidade , Prata/toxicidade , Suor , Têxteis
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