Molecular Toxicity of Metal Oxide Nanoparticles in Danio rerio

Driving Role of Zinc Oxide Nanoparticles with Different Sizes and Hydrophobicity in Metabolic Response and Eco-Corona Formation in Sprouts (Vigna radiata)

Zinc oxide nanoparticles (ZnO NPs) cause biotoxicity and pose a potential ecological threat; however, their effects on plant metabolism and eco-corona evolution between NPs and organisms remain unclear. This study clarified the molecular mechanisms underlying physiological and metabolic responses induced by three different ZnO NPs with different sizes and hydrophobicity in sprouts (Vigna radiata) and explored the critical regulation of eco-corona formation in root-nano systems. Results indicated that smaller-sized ZnO inhibited root elongation by up to 37.14% and triggered oxidative burst and apoptosis. Metabolomics confirmed that physiological maintenance after n-ZnO exposure was mainly attributed to the effective stabilization of nitrogen fixation and defense systems by biotransformation of the flavonoid pathway. Larger-sized or hydrophobic group-modified ZnO exhibited low toxicity in sprouts, with 0.89-fold upregulation of citrate in central carbon metabolism. This contributed to providing energy for resistance to NP stress through amino acid and carbon/nitrogen metabolism, accompanied by changes in membrane properties. Notably, smaller-sized and hydrophobic NPs intensely stimulated the release of root metabolites, forming corona complexes with exudates. The hydrogen-bonded wrapping mechanism in protein secondary structure and hydrophobic interactions of heterogeneous functional groups drove eco-corona formation, along with the corona evolution intensity of n-ZnO > s-ZnO > b-ZnO based on higher (α-helix + 3-turn helix)/β-sheet ratios. This study provides crucial insight into metabolic and eco-corona evolution in bionano fates.

Response of anammox consortia to inhibition from high ferroferric oxide nanoparticles concentration and potential recovery mechanism

The substantial discharge of ferroferric oxide nanoparticles (Fe3O4 NPs) into sewage threatens the survival of functional microorganisms in wastewater treatment. This study elucidated responses of anaerobic ammonium oxidation (anammox) consortia to inhibition from high Fe3O4 NPs concentration and recovery mechanisms. The nitrogen removal efficiency decreased by 20.3 % and recovered after 55 days under 1000 mg/L Fe3O4 NPs concentration. Toxicity was attributed to reactive oxygen species (ROS) production. The excessive ROS damaged membrane integrity, nitrogen metabolism, and DNA synthesis, resulting in the inhibition of anammox bacteria activity. However, recovery mechanisms of anammox consortia activity were activated in response to 1000 mg/L Fe3O4 NPs. The increase of heme oxygenase-1, thioredoxin, and nicotinamide adenine dinucleotide-quinone oxidoreductase genes alleviated oxidative stress. Furthermore, the activation of metabolic processes associated with membrane and DNA repair promoted recovery of anammox bacteria activity. This study provided new insights into NPs contamination and control strategies during anammox process.

Remediation of Metal Oxide Nanotoxicity with a Functional Amyloid

Understanding the environmental health and safety of nanomaterials (NanoEHS) is essential for the sustained development of nanotechnology. Although extensive research over the past two decades has elucidated the phenomena, mechanisms, and implications of nanomaterials in cellular and organismal models, the active remediation of the adverse biological and environmental effects of nanomaterials remains largely unexplored. Inspired by recent developments in functional amyloids for biomedical and environmental engineering, this work shows their new utility as metallothionein mimics in the strategically important area of NanoEHS. Specifically, metal ions released from CuO and ZnO nanoparticles are sequestered through cysteine coordination and electrostatic interactions with beta-lactoglobulin (bLg) amyloid, as revealed by inductively coupled plasma mass spectrometry and molecular dynamics simulations. The toxicity of the metal oxide nanoparticles is subsequently mitigated by functional amyloids, as validated by cell viability and apoptosis assays in vitro and murine survival and biomarker assays in vivo. As bLg amyloid fibrils can be readily produced from whey in large quantities at a low cost, the study offers a crucial strategy for remediating the biological and environmental footprints of transition metal oxide nanomaterials.

Molecular level toxicity effects of As(V) on Folsomia candida: Integrated transcriptomics and metabolomics analyses

Arsenic (As) is a widespread metalloid with well-known toxicity. To date, numerous studies have focused on individual level toxicity (e.g., growth and reproduction) of As to typical invertebrate springtails in soils, however, the molecular level toxicity and mechanism was poorly understood. Here, an integrated transcriptomics and metabolomics approach was used to reveal responses of Folsomia candida exposed to As(V) of 10 and 60 mg kg-1 at which the individual level endpoints were influenced. Transcriptomics identified 5349 and 4020 differentially expressed genes (DEGs) in low and high concentration groups, respectively, and the most DEGs were down-regulated. Enrichment analysis showed that low and high concentrations of As(V) significantly inhibited chromatin/chromosome-related biological processes (chromatin/chromosome organization, nucleosome assembly and organization, etc.) in springtails. At high concentration treatment, structural constituent of cuticle, chitin metabolic process and peptidase activity (serine-type peptidase activity, endopeptidase activity, etc.) were inhibited or disturbed. Moreover, the apoptosis pathway was significantly induced. Metabolomics analysis identified 271 differential changed metabolites (DCMs) in springtails exposed to high concentration of As. Steroid hormone biosynthesis was the most significantly affected pathway. Several DCMs that related to chitin metabolism could further support above transcriptomic results. These findings further extended the knowledge of As toxic mechanisms to soil fauna and offer important information for the environmental risk assessment.

Mechanistic study of C5F10O-induced lung toxicity in rats: An eco-friendly insulating gas alternative to SF6

The global warming and other environmental problems caused by SF6 emissions can be reduced due to the widespread use of eco-friendly insulating gas, perfluoropentanone (C5F10O). However, there is an exposure risk to populations in areas near C5F10O equipment, so it is important to clarify its biosafety and pathogenesis before large-scale application. In this paper, histopathology, transcriptomics, 4D-DIA proteomics, and LC-MS metabolomics of rats exposed to 2000 ppm and 6000 ppm C5F10O are analyzed to reveal the mechanisms of toxicity and health risks. Histopathological shows that inflammatory cell infiltration, epithelial cell hyperplasia, and alveolar atrophy accompanied by alveolar wall thickening are present in both low-dose and high-dose groups. Analysis of transcriptomic and 4D-DIA proteomic show that Cell cycle and DNA replication can be activated by both 2000 ppm and 6000 ppm C5F10O to induce cell proliferation. In addition, it also leads to the activation of pathways such as Antigen processing and presentation, Cell adhesion molecules and Complement and coagulation cascades, T cell receptor signal path, Th1 and T cell receptor signal path, Th1 and Th2 cell differentiation, complement and coagulation cascades. Finally, LC-MS metabolomics analysis confirms that the metabolic pathways associated with glycerophospholipids, arachidonic acid, and linoleic acid are disrupted and become more severe with increasing doses. The mechanism of lung toxicity caused by C5F10O is systematically expounded based on the multi-omics analysis and provided biosafety references for further promotion and application of C5F10O.

In vivo toxicological assessment of silver nanoparticle in edible fish, Oreochromis mossambicus

Silver nanoparticles are the extensively utilized among all nanoparticles due to their antibacterial and wound healing properties making them highly suitable for medical and pharmaceutical applications. The field of nanoparticle toxicity is an emerging field and the present study aims to assess the biochemical, hematological and genotoxicity in Oreochromis mossambicus exposed to different concentrations of silver nanoparticles for 7 and 14 days. Silver nanoparticles were synthesized by reduction of silver nitrate using trisodium citrate and was characterized using X-ray diffraction, SEM, HRTEM and DLS. Hematological parameters like RBC, WBC, Hb, HCT and MCV and for biochemical analysis, antioxidant enzymes SOD, CAT and GPX and serum enzymes AST, ALT, ACP, ALP and LDH were analyzed. Genotoxicity was studied using comet assay. Results obtained showed decrease in erythrocytes, HCT, Hb and MCV while an increase was noted in WBC on day 7 and 14. The antioxidant enzymes SOD, CAT and GPx showed a decrease and the lipid peroxidation product MDA was elevated. The serum enzymes AST, ALT, ACP ALP and LDH showed an increased activity when compared to control. DNA damage was evident by an increase in % TDNA. The results indicate hematological, biochemical and genotoxicity of silver nanoparticles that might be mediated through ROS generation in O. mossambicus.

Toxicity of Titanium Dioxide-Cerium Oxide Nanocomposites to Zebrafish Embryos: A Preliminary Evaluation

The widespread use of metal nanoparticles in different fields has raised many doubts regarding their possible toxicity to living organisms and the accumulation and discharge of metals in fish species. Among these nanoparticles, titanium dioxide (TiO2) and cerium oxide (CeO2) nanoparticles have mainly been employed in photocatalysis and water depuration. The aim of this research was to evaluate the potential toxic effects, after a co-exposure of TiO2-3%CeO2 nanoparticles, on zebrafish development, using an acute toxicity test. Increasing concentrations of TiO2-3%CeO2 nanoparticles were used (0.1-1-10-20 mg/L). The heartbeat rate was assessed using DanioscopeTM software (version 1.2) (Noldus, Leesburg, VA, USA), and the responses to two biomarkers of exposure (Heat shock proteins-70 and Metallothioneins) were evaluated through immunofluorescence. Our results showed that the co-exposure to TiO2-3%CeO2 nanoparticles did not affect the embryos' development compared to the control group; a significant difference (p < 0.05) at 48 hpf heartbeat for the 1, 10, and 20 mg/L groups was found compared to the unexposed group. A statistically significant response (p < 0.05) to Heat shock proteins-70 (Hsp70) was shown for the 0.1 and 1 mg/L groups, while no positivity was observed in all the exposed groups for Metallothioneins (MTs). These results suggest that TiO2-3%CeO2 nanocomposites do not induce developmental toxicity; instead, when considered separately, TiO2 and CeO2 NPs are harmful to zebrafish embryos, as previously shown.

Copper oxide nanoparticles: In vitro and in vivo toxicity, mechanisms of action and factors influencing their toxicology

Copper oxide nanoparticles (CuO NPs) have received increasing interest due to their distinctive properties, including small particle size, high surface area, and reactivity. Due to these properties, their applications have been expanded rapidly in various areas such as biomedical properties, industrial catalysts, gas sensors, electronic materials, and environmental remediation. However, because of these widespread uses, there is now an increased risk of human exposure, which could lead to short- and long-term toxicity. This review addresses the underlying toxicity mechanisms of CuO NPs in cells which include reactive oxygen species generation, leaching of Cu ion, coordination effects, non-homeostasis effect, autophagy, and inflammation. In addition, different key factors responsible for toxicity, characterization, surface modification, dissolution, NPs dose, exposure pathways and environment are discussed to understand the toxicological impact of CuO NPs. In vitro and in vivo studies have shown that CuO NPs cause oxidative stress, cytotoxicity, genotoxicity, immunotoxicity, neurotoxicity, and inflammation in bacterial, algal, fish, rodents, and human cell lines. Therefore, to make CuO NPs a more suitable candidate for various applications, it is essential to address their potential toxic effects, and hence, more studies should be done on the long-term and chronic impacts of CuO NPs at different concentrations to assure the safe usage of CuO NPs.

Differences of functionalized graphene materials on inducing chronic aquatic toxicity through the regulation of DNA damage, metabolism and oxidative stress in Daphnia magna

Graphene can be modified with functional groups when released into the environment. However, very little is known about molecular mechanisms of chronic aquatic toxicity induced by graphene nanomaterials with different surface functional groups. By using RNA sequencing, we investigated the toxic mechanisms of unfunctionalized graphene (u-G), carboxylated graphene (G-COOH), aminated graphene (G-NH₂), hydroxylated graphene (G-OH) and thiolated graphene (G-SH) to Daphnia magna during 21-day exposure. We revealed that alteration of ferritin transcription levels in the "mineral absorption" signaling pathway is a molecular initiating event leading to potential of oxidative stress in Daphnia magna by u-G, while toxic effects of four functionalized graphenes are related to several metabolic pathways including the "protein digestion and absorption" pathway and "carbohydrate digestion and absorption" pathway. The transcription and translation related pathways were inhibited by G-NH₂ and G-OH, which further affected the functions of proteins and normal life activities. Noticeably, detoxifications of graphene and its surface functional derivatives were promoted by increasing the gene expressions related to chitin and glucose metabolism as well as cuticle structure components. These findings demonstrate important mechanistic insights that can potentially be employed for safety assessment of graphene nanomaterials.

Synthesis, biomedical applications, and toxicity of CuO nanoparticles

Versatile nature of copper oxide nanoparticles (CuO NPs) has made them an imperative nanomaterial being employed in nanomedicine. Various physical, chemical, and biological methodologies are in use for the preparation of CuO NPs. The physicochemical and biological properties of CuO NPs are primarily affected by their method of fabrication; therefore, selectivity of a synthetic technique is immensely important that makes these NPs appropriate for a specific biomedical application. The deliberate use of CuO NPs in biomedicine questions their biocompatible nature. For this reason, the present review has been designed to focus on the approaches employed for the synthesis of CuO NPs; their biomedical applications highlighting antimicrobial, anticancer, and antioxidant studies; and most importantly, the in vitro and in vivo toxicity associated with these NPs. This comprehensive overview of CuO NPs is unique and novel as it emphasizes on biomedical applications of CuO NPs along with its toxicological assessments which would be useful in providing core knowledge to researchers working in these domains for planning and conducting futuristic studies. KEY POINTS: • The recent methods for fabrication of CuO nanoparticles have been discussed with emphasis on green synthesis methods for different biomedical approaches. • Antibacterial, antioxidant, anticancer, antiparasitic, antidiabetic, and antiviral properties of CuO nanoparticles have been explained. • In vitro and in vivo toxicological studies of CuO nanoparticles exploited along with their respective mechanisms.

The impact of engineered nanomaterials on the environment: Release mechanism, toxicity, transformation, and remediation

The presence and longevity of nanomaterials in the ecosystem, as well as their properties, account for environmental toxicity. When nanomaterials in terrestrial and aquatic systems are exposed to the prevailing environmental conditions, they undergo various transformations such as dissociation, dissolution, and aggregation, which affects the food chain. The toxicity of nanomaterials is influenced by a variety of factors, including environmental factors and its physico-chemical characteristics. Bioaccumulation, biotransformation, and biomagnification are the mechanisms that have been identified for determining the fate of nanomaterials. The route taken by nanomaterials to reach living cells provides us with information about their toxicity profile. This review discusses the recent advances in the transport, transformation, and fate of nanomaterials after they are released into the environment. The review also discusses how nanoparticles affect lower trophic organisms through direct contact, the impact of nanoparticles on higher trophic organisms, and the possible options for remediation.

Comprehensive Review on the Degradation Chemistry and Toxicity Studies of Functional Materials

In recent decades there has been growing interest of material chemists in the successful development of functional materials for drug delivery, tissue engineering, imaging, diagnosis, theranostic, and other biomedical applications with advanced nanotechnology tools. The efficacy and safety of functional materials are determined by their pharmacological, toxicological, and immunogenic effects. It is essential to consider all degradation pathways of functional materials and to assess plausible intermediates and final products for quality control. This review provides a brief insight into chemical degradation mechanisms of functional materials like oxidation, photodegradation, and physical and enzymatic degradation. The intermediates and products of degradation were confirmed with analytical methods such as proton nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC), UV-vis spectroscopy (UV-vis), infrared spectroscopy (IR), differential scanning calorimetry (DSC), mass spectroscopy, and other sophisticated analytical methods. These analytical methods are also used for regulatory, quality control, and stability purposes in industry. The assessment of degradation is important to predetermine the behavior of functional materials in specific storage conditions and can be relevant to their behavior during in vivo applications. Another important aspect is the evaluation of the toxicity of functional materials. Toxicity can be accessed with various methods using in vitro, in vivo, ex vivo, and in silico models. In vitro cell culture methods are used to determine mitochondrial damage, reactive oxygen species, stress responses, and cellular toxicity. In vitro cellular toxicity can be measured by MTT assay, LDH leakage assay, and hemolysis. In vivo studies are performed using various animal models involving zebrafish, rodents (mice and rats), and nonhuman primates. Ex vivo studies are also used for efficacy and toxicity determinations of functional materials like ex vivo potency assay and precision-cut liver slice (PCLS) models. The in silico tools with computational simulations like quantitative structure-activity relationships (QSAR), pharmacokinetics (PK) and pharmacodynamics (PD), dose and time response, and quantitative cationic-activity relationships ((Q)CARs) are used for prediction of the toxicity of functional materials. In this review, we studied the principle methods used for degradation studies, different degradation pathways, and mechanisms of functional material degradation with prototype examples. We discuss toxicity assessments with different toxicity approaches used for estimation of the safety and efficacy of functional materials.

The High-Throughput In Vitro CometChip Assay for the Analysis of Metal Oxide Nanomaterial Induced DNA Damage

Metal oxide nanomaterials (MONMs) are among the most highly utilized classes of nanomaterials worldwide, though their potential to induce DNA damage in living organisms is known. High-throughput in vitro assays have the potential to greatly expedite analysis and understanding of MONM induced toxicity while minimizing the overall use of animals. In this study, the high-throughput CometChip assay was used to assess the in vitro genotoxic potential of pristine copper oxide (CuO), zinc oxide (ZnO), and titanium dioxide (TiO2) MONMs and microparticles (MPs), as well as five coated/surface-modified TiO2 NPs and zinc (II) chloride (ZnCl2) and copper (II) chloride (CuCl2) after 2–4 h of exposure. The CuO NPs, ZnO NPs and MPs, and ZnCl2 exposures induced dose- and time-dependent increases in DNA damage at both timepoints. TiO2 NPs surface coated with silica or silica–alumina and one pristine TiO2 NP of rutile crystal structure also induced subtle dose-dependent DNA damage. Concentration modelling at both post-exposure timepoints highlighted the contribution of the dissolved species to the response of ZnO, and the role of the nanoparticle fraction for CuO mediated genotoxicity, showing the differential impact that particle and dissolved fractions can have on genotoxicity induced by MONMs. The results imply that solubility alone may be insufficient to explain the biological behaviour of MONMs.

Nanoparticle pre- or co-exposure affects bacterial ingestion by the protozoan Tetrahymena thermophila

Although nanoparticles' (NPs) toxicity has been intensively studied, their effects on bacterial ingestion by protozoans (as an important component of the microbial loop) is unknown. This study investigated the effects of NPs of different chemical composition [hematite (HemNPs), anatase (AnaNPs), and silica (SiNPs) NPs] and size [SiNPs with particle size of 20 (Si-20), 100 (Si-100), and 500 (Si-500) nm] on the ingestion of Escherichia coli by the protozoan Tetrahymena thermophila. Potential differences between pre- vs. co-exposure were also assessed. Pre-exposure to HemNPs had no effects on bacterial ingestion but the other NPs caused a significant inhibition, due to their inhibition of ATP synthesis and the down-regulation of phagocytosis-related genes (ACT1 and CTHB). Contrastively, co-exposure to HemNPs and Si-20 didn't affect bacterial ingestion while co-exposure to AnaNPs (Si-100 and Si-500) induced (inhibited) ingestion. The stimulatory effect of AnaNPs was due to their induction of an increase in the intracellular Ca concentration of T. thermophila whereas the inhibitory effects of Si-100 and Si-500 were attributable to ATP synthesis reduction, enhanced bacterial cell aggregation, and competition between the bacterial cells and the NPs. These findings provide insights into the mechanisms underlying the environmental risks of NPs.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×106 particles/cm3, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m3 continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3-CD19+ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

A New Look at the Effects of Engineered ZnO and TiO2 Nanoparticles: Evidence from Transcriptomics Studies

Titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles (NPs) have attracted a great deal of attention due to their excellent electrical, optical, whitening, UV-adsorbing and bactericidal properties. The extensive production and utilization of these NPs increases their chances of being released into the environment and conferring unintended biological effects upon exposure. With the increasingly prevalent use of the omics technique, new data are burgeoning which provide a global view on the overall changes induced by exposures to NPs. In this review, we provide an account of the biological effects of ZnO and TiO2 NPs arising from transcriptomics in in vivo and in vitro studies. In addition to studies on humans and mice, we also describe findings on ecotoxicology-related species, such as Danio rerio (zebrafish), Caenorhabditis elegans (nematode) or Arabidopsis thaliana (thale cress). Based on evidence from transcriptomics studies, we discuss particle-induced biological effects, including cytotoxicity, developmental alterations and immune responses, that are dependent on both material-intrinsic and acquired/transformed properties. This review seeks to provide a holistic insight into the global changes induced by ZnO and TiO2 NPs pertinent to human and ecotoxicology.

Investigating the toxically homogenous effects of three lanthanides on zebrafish

The adverse effects of rare earth elements (REEs) have been increasingly reported in the past decades and have raised concern about their environmental toxicities. However, the available data is insufficient to elucidate the toxic effects, mechanisms, and whether the toxicity across all REEs is uniform. In this study, zebrafish were exposed to 0, 0.8, 1.6, 3.2, 6.4, 12.8 and 25.6 mg/L Ln(NO₃)₃•6H₂O to test the acute toxicity of La(III), Ce(III), and Nd(III). LC₅₀ of the three lanthanides was compared to the extent of the impact on gene expression. We carried out the functionally grouped network-based transcriptome analysis using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) to explore the molecular mechanisms. The acute toxicity test showed that LC₅₀ of La(III), Ce(III), and Nd(III) were 2.53, 2.03, and 2.76 mg/L, respectively. Consistent with acute toxicity, Ce(III) caused a little more DEGs than La(III) and Nd(III). Some biological processes such as metabolism of xenobiotics, oocyte meiosis, steroid biosynthesis, DNA replication, and p53 signaling pathway were affected following exposure of all the three lanthanides. Ce(III) also induced changes in the chemokine-mediated signaling pathway. The results indicated that the lethality is comparable, and the toxic patterns are similar across the three lanthanides. This study gives comparative research on the toxicities of three lanthanides to model organism zebrafish.

Mitochondria-Dependent Oxidative Stress Mediates ZnO Nanoparticle (ZnO NP)-Induced Mitophagy and Lipotoxicity in Freshwater Teleost Fish

Due to many special characteristics, zinc oxide nanoparticles (ZnO NPs) are widely used all over the world, leading to their wide distribution in the environment. However, the toxicities and mechanisms of environmental ZnO NP-induced changes of physiological processes and metabolism remain largely unknown. Here, we found that addition of dietary ZnO NPs disturbed hepatic Zn metabolism, increased hepatic Zn and lipid accumulation, downregulated lipolysis, induced oxidative stress, and activated mitophagy; N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN, Zn²⁺ ions chelator) alleviated high ZnO NP-induced Zn and lipid accumulation, oxidative stress, and mitophagy. Mechanistically, the suppression of mitochondrial oxidative stress attenuated ZnO NP-activated mitophagy and ZnO NP-induced lipotoxicity. Taken together, our study elucidated that mitochondrial oxidative stress mediated ZnO NP-induced mitophagy and lipotoxicity; ZnO NPs could be dissociated to free Zn²⁺ ions, which partially contributed to ZnO NP-induced changes in oxidative stress, mitophagy, and lipid metabolism. Our study provides novel insights into the impacts and mechanism of ZnO NPs as harmful substances inducing lipotoxicity of aquatic organisms, and accordingly, metabolism-relevant parameters will be useful for the risk assessment of nanoparticle materials in the environment.

Acute Adverse Effects of Metallic Nanomaterials on Cardiac and Behavioral Changes in Daphnia magna

Nanomaterials are widely believed to induce toxic effects on organisms by evoking oxidative stress. We evaluated the toxic effects of nanomaterials on the cardiac and behavioral changes in Daphnia magna under varying exposure conditions. Titanium dioxide nanoparticles (TiO2 NPs), silver nanoparticles (AgNPs), and silver nitrate (AgNO3) were selected for the acute toxicity tests. The adverse effects of the substances on the neonates including heart rate, swimming speed, and oxidative stress were measured. The heart rate level decreased as the concentration of both NPs and silver ions (Ag+) increased. The average swimming speed was measured to be approximately 15 mm/min for the control group. The swimming speed generally increased with a longer exposure to both NPs although it reached a plateau at the lowest concentration of AgNPs. A similar but less clear trend was observed for Ag+. For all substances, the overall swimming speed exhibited no correlation or weak negative correlations with the exposure concentration. The oxidative stress levels increased after exposure compared with the control group. We conclude that aquatic nanotoxicity tests should consider multilevel physicochemical, physiological, and behavioral parameters for the official guidelines to quantify more robust adverse outcomes.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×10⁶ particles/cm³, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m³ continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, and CD3^-CD19⁺ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

Integrated in silico analysis for the identification of key genes and signaling pathways in copper oxide nanoparticles toxicity

Copper oxide nanoparticles (CuO-NPs) are used in various industrial and commercial products due to their enhanced physicochemical properties. The vast consumption increases their exposure in the environment, thereby affecting the ecosystem. Even with the rise in research towards understanding their toxicity, the major signaling cascades and key genes involved in CuO-NPs remain elusive due to the various attributes involved (size, shape, charge, coating in terms of nanoparticles, and dose, duration, and species used in the experiment). The focus of the study is to identify the key signaling cascades and genes involved in CuO-NPs toxicity irrespective of these attributes. CuO-NPs related microarray expression profiles were screened from GEO database and were subjected to toxicogenomic analysis to elucidate the toxicity mechanism. In silico tools were used to obtain the DEGs, followed by GO and KEGG functional enrichment analysis. The identified DEGs were then analyzed to determine major signaling pathways and key genes. Module and centrality parameter analysis was performed to identify the key genes. Further, the miRNAs and transcription factors involved in regulating the genes were predicted, and their interactive pathways were constructed. A total of 44 DEGs were commonly present in all the analysed datasets and all of them were downregulated. GO analysis reveals that most of the genes were enriched in functions related to cell division and chemotaxis. Cell-cycle, chemokine, cytokine-cytokine receptor interaction, and p53 signaling pathways were the key pathways with Cdk1 as the major biomarker altered irrespective of the variables (dosage, duration, species used, and surface coating). Overall, our integrated toxicogenomic analysis reveal that Cdk1 regulated cell cycle and cytokine-cytokine signaling cascades might be responsible for CuO-NPs toxicity. These findings will help us in understanding the mechanisms involved in NPs toxicity.

A Caffeic Acid Matrix Improves In Situ Detection and Imaging of Proteins with High Molecular Weight Close to 200,000 Da in Tissues by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

To our knowledge, this was the first study in which caffeic acid (CA) was successfully evaluated as a matrix to enhance the in situ detection and imaging of endogenous proteins in three biological tissue sections (i.e., a rat brain and Capparis masaikai and germinating soybean seeds) by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Our results show several properties of CA, including strong ultraviolet absorption, a super-wide MS detection mass range close to 200,000 Da, micrometer-sized matrix crystals, uniform matrix deposition, and high ionization efficiency. More high-molecular-weight (HMW) protein ion signals (m/z > 30,000) could be clearly detected in biological tissues with the use of CA, compared to two commonly used MALDI matrices, i.e., sinapinic acid (SA) and ferulic acid (FA). Notably, CA shows excellent performance for HMW protein in situ detection from biological tissues in the mass range m/z > 80,000, compared to the use of SA and FA. Furthermore, the use of a CA matrix also significantly enhanced the imaging of proteins on the surface of selected biological tissue sections. Three HMW protein ion signals (m/z 50,419, m/z 65,874, and m/z 191,872) from a rat brain, two sweet proteins (mabinlin-2 and mabinlin-4) from a Capparis masaikai seed, and three HMW protein ion signals (m/z 94,838, m/z 134,204, and m/z 198,738) from a germinating soybean seed were successfully imaged for the first time. Our study proves that CA has the potential to become a standard organic acid matrix for enhanced tissue imaging of HMW proteins by MALDI-MSI in both animal and plant tissues.

Photoinduced transformation of silver ion by molybdenum disulfide nanoflakes at environmentally relevant concentrations attenuates its toxicity to freshwater algae

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 (MoO₄^2-) 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.

Oxidative degradation and mineralization of the endocrine disrupting chemical bisphenol-A by an eco-friendly system based on UV-solar/H2O2 with reduction of genotoxicity and cytotoxicity levels

A solar-driven advanced oxidation process at a lab scale was studied for the degradation and mineralization of the known endocrine disrupting chemical (EDC), bisphenol A (BPA). Preliminary tests were performed varying the irradiation source, BPA/H₂O₂ ratio, temperature, initial H₂O₂ concentration, initial solution pH, and initial BPA concentration, then, the operational conditions of the UV-solar/H₂O₂ were optimized by a response surface methodology (RSM), providing the following responses: UV-solar/H₂O₂ process at pH 3.0, [BPA]₀ = 25 mg L^-1, [H₂O₂] = 350 mg L^-1, T = 50 °C, achieving BPA degradation of 77.4% and BPA mineralization of 38.2%, H₂O₂ consumption of 230 mg L^-1. From the optimized condition, different pH ranges were tested (3.0; 5.0; 7.0; 9.0; and 11.0), where, at solution pH 5.0 the best removal rates were achieved (89.2% BPA degradation and 49.0% BPA mineralization). The BPA amount in solution was monitored by High Performance Liquid Chromatography (HPLC) and a study of the intermediate reaction by-products was performed by Gas Chromatography-Mass Spectrometry (GC-MS) analyses, highlighting the lower amount of by-products identified when the solution pH 5.0 was employed, rather than the solution pH 3.0. Genotoxicity tests with Zebrafish (Danio rerio) and cytotoxicity tests with Allium cepa were performed aiming to evaluate errors in the cells and nuclear abnormalities of the tested organisms induced by BPA raw samples, as well as by the BPA samples treated by the UV-solar/H₂O₂ process. Therefore, the bio-toxicity levels for an animal and a vegetal bio-indicator were reduced by applying a renewable source of energy as the irradiation source for the UV/H₂O₂ process, representing an efficient and eco-friendly alternative for BPA treatment in aqueous solutions.

Zebrafish (Danio rerio) using as model for genotoxicity and DNA repair assessments: Historical review, current status and trends

Genotoxic pollutants lead to both DNA damage and changes in cell repair mechanisms. Selecting suitable biomonitors is a fundamental step in genotoxicity studies. Thus, zebrafish have become a popular model used to assess the genotoxicity of different pollutants in recent years. They have orthologous genes with humans and hold almost all genes involved in different repair pathways. Therefore, the aim of the current study is to summarize the existing literature on zebrafish using as model system to assess the genotoxicity of different pollutants. Revised data have shown that comet assay is the main technique adopted in these studies. However, it is necessary standardizing the technique applied to zebrafish in order to enable better result interpretation and comparisons. Overall, pollutants lead to single-strand breaks (SSB), double-strand breaks (DSB), adduct formation, as well as to changes in the expression of genes involved in repair mechanisms. Although analyzing repair mechanisms is essential to better understand the genotoxic effects caused by pollutants, few studies have analyzed repair capacity. The current review reinforces the need of conducting further studies on the role played by repair pathways in zebrafish subjected to DNA damage. Revised data have shown that zebrafish are a suitable model to assess pollutant-induced genotoxicity.

Effectiveness and Mechanisms of Recoverable Magnetic Nanoparticles on Mitigating Golden Mussel Biofouling

Mussel biofouling has become a problem in aquatic ecosystems, causing significant ecological impact and huge economic loss globally. Although several strategies have been proposed and tested, efficient and environment-friendly antifouling methods are still scarce. Here, we investigated the effects of recoverable magnetic ferroferric oxide nanoparticles (Fe₃O₄-NPs) with different sizes (10 and 100 nm), coatings (polyethylene glycol and polylysine), and concentrations (0.01 and 0.1 mg/L) on byssus adhesion-mediated biofouling by the notorious golden mussel Limnoperna fortunei. The results showed that magnetic Fe₃O₄-NPs, especially negatively charged polyethylene glycol-coated Fe₃O₄-NPs, size- and concentration-dependently reduced the byssus production, performance (breaking force and failure location), and adhesion rate. Further investigations on mechanisms showed that the down-regulation of foot protein 2 (Lffp-2) and energy-related metabolic pathways inhibited byssus production. The declined gene expression level and metal-binding ability of Lffp-2 significantly affected foot protein interactions, further reducing the plaque size and byssus performance. In addition, the change in the water redox state likely reduced byssus performance by preventing the interface interactions between the substrate and foot proteins. Our results confirm the effectiveness and underlying mechanisms of magnetic Fe₃O₄-NPs on mitigating L. fortunei biofouling, thus providing a reference for developing efficient and environment-friendly antifouling strategies against fouling mussels.

Developmental toxicity induced by Cu(OH)2 nanopesticide in zebrafish embryos

The current study evaluates the adverse effects of Cu(OH)₂ nanopesticide (CNPE) on the early life stages of zebrafish (Danio rerio). The developmental toxicity was determined using different parameters such as mortality (including LC₅₀ ), hatching, heart rates, malformations, and alteration of the gene expressions. Zebrafish embryos (4 hpf-hours postfertilization) were exposed to 1.0, 2.0, 4.0, 8.0, and 16.0 mg/l CNPE doses until 96 hpf. The 96 hours LC₅₀ was recorded at 6.258 mg/l. Seventy-two hpf total malformation index values for 2.0, 4.0, and 8.0 mg/l CNPE doses were 4.3, 7.2 and 7.9, respectively. 1.0 mg/l CNPE is not toxic for the zebrafish embryos/larvae. 2.0 to 8.0 CNPE doses caused some abnormalities in embryos/larvae morphology, including lack of body parts, tail deformities, chorda deformity, bubbled head, scoliosis, lordosis, weak or non-pigmentation, decreased heart rate and larva length. 16.0 mg/l CNPE caused mortality in 72 hpf. The expression levels of seven immune system-related genes (il-1β, il-8, cebp, tlr4, hsp70, NF-kB, and mtf-1) were examined. The transcription level of il-1β, il-8, tlr4, hsp70, and NF-kB genes significantly increased in the CNPE exposure groups. While the expression of the mtf-1 gene considerably decreased, the cebp gene expression level did not change in the 4.0 and 8.0 mg/l CNPE doses. In conclusion, CNPE could induce developmental toxicity with malformations in embryos/larvae and alter the gene expression.

Exposure of CuO nanoparticles and their metal counterpart leads to change in the gut microbiota and resistome of collembolans

The widespread use of copper oxide nanoparticles (CuONPs) has dramatically increased their concentrations in soils and severely affected the health of soil organisms. The gut microbiota critically contributes to the metabolism and immune system of its host and is sensitive to environmental pollution. The toxic effect of CuONPs on the gut microbiota, especially in soil fauna, still needs further research. In the present study, a comprehensive toxicological test was performed to reveal the effects of CuONPs and their metal counterpart on the gut microbiota of soil collembolans using Illumina high throughput sequencing. Furthermore, the concomitant changes in the collembolans gut-associated antibiotic resistance genes (ARGs) and metabolism were investigated using high-throughput quantitative PCR and carbon and nitrogen stable isotope compositions. Both CuONPs and ionic copper (Cu) exposure disturbed the collembolan gut microbial community structure while only CuONPs reduced the gut microbial diversity. A total of 66 ARGs were detected in the collembolan guts, and CuONPs exposure induced a reduction in both diversity and abundance of ARGs. Additionally, CuONPs and ionic Cu exposure altered the C and N stable isotope compositions of the collembolans, indicating a change in their metabolism. Moreover, structural equation modeling indicated that 85.5% of the carbon stable isotope variations and 73.3% of the nitrogen stable isotope variations were explained by changes in Cu bioaccumulation and the gut microbiota. The results of the present study extend our knowledge regarding the comprehensive toxicity of metal oxide NPs on soil fauna.

Toxicity of copper oxide nanoparticles: a review study

Copper oxide nanoparticles (CuO NPs) use has exponentially increased in various applications (such as industrial catalyst, gas sensors, electronic materials, biomedicines, environmental remediation) due to their flexible properties, i.e. large surface area to volume ratio. These broad applications, however, have increased human exposure and thus the potential risk related to their short- and long-term toxicity. Their release in environment has drawn considerable attention which has become an eminent area of research and development. To understand the toxicological impact of CuO NPs, this review summarises the in-vitro and in-vivo toxicity of CuO NPs subjected to species (bacterial, algae, fish, rats, human cell lines) used for toxicological hazard assessment. The key factors that influence the toxicity of CuO NPs such as particle shape, size, surface functionalisation, time-dose interaction and animal and cell models are elaborated. The literature evidences that the CuO NPs exposure to the living systems results in reactive oxygen species generation, oxidative stress, inflammation, cytotoxicity, genotoxicity and immunotoxicity. However, the physio-chemical characteristics of CuO NPs, concentration, mode of exposure, animal model and assessment characteristics are the main perspectives that define toxicology of CuO NPs.

Metal Nanoparticles in Infection and Immunity

Background Enthusiasm for the use of metal nanoparticles in human and veterinary medicine is high. Many articles describe the effects of metal nanoparticles on microbes in vitro, and a smaller number of articles describe effects on the immune system, which is the focus of this review. Methods Articles were retrieved by performing literature searches in Medline, of the National Institute of Medicine, as well as via Google Scholar. Results In vitro studies show that metal nanoparticles have antimicrobial effects. Some metal nanoparticles augment innate host immune defenses, such as endogenous antimicrobial peptides, and nitric oxide. Metal nanoparticles may also function as vaccine adjuvants. Metal nanoparticles can migrate to locations distant from the site of administration, however, requiring careful monitoring for toxicity. Conclusions Metal nanoparticles show a great deal of potential as immunomodulators, as well as direct antimicrobial effects. Before metal particles can be adopted as therapies; however, more studies are needed to determine how nanoparticles migrate though the body and on possible adverse effects.

Transcriptome analysis in Parhyale hawaiensis reveal sex-specific responses to AgNP and AgCl exposure

Analysis of the transcriptome of organisms exposed to toxicants offers new insights for ecotoxicology, but further research is needed to enhance interpretation of results and effectively incorporate them into useful environmental risk assessments. Factors that must be clarified to improve use of transcriptomics include assessment of the effect of organism sex within the context of toxicant exposure. Amphipods are well recognized as model organisms for toxicity evaluation because of their sensitivity and amenability to laboratory conditions. To investigate whether response to metals in crustaceans differs according to sex we analyzed the amphipod Parhyale hawaiensis after exposure to AgCl and Ag nanoparticles (AgNP) via contaminated food. Gene specific analysis and whole genome transcriptional profile of male and female organisms were performed by both RT-qPCR and RNA-seq. We observed that expression of transcripts of genes glutathione transferase (GST) did not differ among AgCl and AgNP treatments. Significant differences between males and females were observed after exposure to AgCl and AgNP. Males presented twice the number of differentially expressed genes in comparison to females, and more differentially expressed were observed after exposure to AgNP than AgCl treatments in both sexes. The genes that had the greatest change in expression relative to control were those genes related to peptidase and catalytic activity and chitin and carbohydrate metabolic processes. Our study is the first to demonstrate sex specific differences in the transcriptomes of amphipods upon exposure to toxicants and emphasizes the importance of considering gender in ecotoxicology.

The Effect of the Chorion on Size-Dependent Acute Toxicity and Underlying Mechanisms of Amine-Modified Silver Nanoparticles in Zebrafish Embryos

As the worldwide application of nanomaterials in commercial products increases every year, various nanoparticles from industry might present possible risks to aquatic systems and human health. Presently, there are many unknowns about the toxic effects of nanomaterials, especially because the unique physicochemical properties of nanomaterials affect functional and toxic reactions. In our research, we sought to identify the targets and mechanisms for the deleterious effects of two different sizes (~10 and ~50 nm) of amine-modified silver nanoparticles (AgNPs) in a zebrafish embryo model. Fluorescently labeled AgNPs were taken up into embryos via the chorion. The larger-sized AgNPs (LAS) were distributed throughout developing zebrafish tissues to a greater extent than small-sized AgNPs (SAS), which led to an enlarged chorion pore size. Time-course survivorship revealed dose- and particle size-responsive effects, and consequently triggered abnormal phenotypes. LAS exposure led to lysosomal activity changes and higher number of apoptotic cells distributed among the developmental organs of the zebrafish embryo. Overall, AgNPs of ~50 nm in diameter exhibited different behavior from the ~10-nm-diameter AgNPs. The specific toxic effects caused by these differences in nanoscale particle size may result from the different mechanisms, which remain to be further investigated in a follow-up study.

Core–shell structured magnetic mesoporous silica supported Schiff-base/Pd: an efficacious and reusable nanocatalyst

Preparation, characterization and catalytic application of a novel magnetic ordered mesoporous silica supported Schiff-base/Pd (Fe₃O₄@MCM-41-SB/Pd) are developed.

The zebrafish embryotoxicity test (ZET) for nanotoxicity assessment: from morphological to molecular approach

Nanotechnology and use of nanomaterials (NMs) improve life quality, economic growth and environmental health. However, the increasing production and use of NMs in commercial products has led to concerns about their potential toxicity on human and environment health, as well as its toxicological classification and regulation. In this context, there is an urgent need to standardize and validate procedures for nanotoxicity testing. Since the zebrafish embryotoxicity test (ZET) has been indicated as a suitable approach for the toxicity assessment of traditional and emergent pollutants, the aim of this review is to summarize the existing literature on embryotoxic and teratogenic effects of NMs on zebrafish. In addition, morphological changes in zebrafish embryos induced by NMs were classified in four reaction models, allowing classification of the mode of action and toxicity of different types of NM. Revised data showed that the interaction and bioaccumulation of NMs on zebrafish embryos were associated to several toxic effects, while the detoxification process was limited. In general, NMs induced delayed hatching, circulatory changes, pigmentation and tegumentary alterations, musculoskeletal disorders and yolk sac alterations on zebrafish embryos. Recommendations for nanotoxicological tests are given, including guidance for future research. This review reinforces the use of the ZET as a suitable approach to assess the health risks of NM exposure.

Graphene oxide mediated reduction of silver ions to silver nanoparticles under environmentally relevant conditions: Kinetics and mechanisms

We systematically investigated the reduction mechanisms and reduction kinetics of silver ions (Ag ions) by graphene oxide (GO) under ambient condition. UV-vis spectroscopy, transmission electron microscopy, and electron diffraction results revealed that silver nanoparticles (Ag NPs) could be formed from aqueous Ag ions in the presence of GO at pH 8 under light. Formation of Ag NPs increased with increasing pH (7.4, 8, and 9) and temperature (from 30 to 90); however, the increasing ionic strength and dissolved oxygen reduced the Ag NPs yield. The Ag ions reduction by GO followed pseudo-first-order kinetics under both dark and light, and light irradiation significantly accelerated the Ag NPs formation induced by GO. The phenolic-OH on GO was the dominating electron donator for Ag ion reduction in dark. Exposure to light increased the concentration of phenolic-OH on the GO surface, thereby stimulating the reduction rate of Ag ions by GO. In addition, the light induced electron-hole pairs on GO surface and light activated oxygen-centered radicals on GO surface promoted the reduction of adsorbed Ag ions by GO. Our findings provide important information for the role of GO in reducing Ag ions to Ag NPs in aquatic environments, and shed light on understanding the environmental fate and risk of both Ag ions and GO materials.

Mechanism of toxic effects of Nano-ZnO on cell cycle of zebrafish (Danio rerio)

The release of nano-zinc oxide (nano-ZnO) into the environment may lead to unpredictable risks, thus it is necessary to study its potential harm to organisms. In this study, zebrafish exposed to nano-ZnO were analyzed through cDNA microarrays to provide insight into the toxic effect of nano-ZnO on aquatic organisms at the molecular level. Results found that nano-ZnO inhibited the normal growth and development of zebrafish and other life activities by affecting the process of cell cycle. The nano-ZnO inhibited the expression of the cyclins (Cycs), cyclin-dependent kinases (CDK) and the minichromosome maintenance (MCM), making the activation of Cyc/CDK complexs (CycD/CDK4, 6; CycE/CDK2; CycA/CDK2) and MCM fail and resulting in DNA replication disorder in different periods (G1, M and G2 phase). Therefore, the normal activities of individual organism such as cell division, differentiation and proliferation and the functions of DNA binding and intracellular transfer were disturbed. These findings contribute to our understanding of the toxicity of ZnO NPs to aquatic organisms, and also provide an evaluation basis for assessing the environmental impact of nano materials.

Effects of cadmium toxicity on diploid wheat (Triticum urartu) and the molecular mechanism of the cadmium response

Cadmium (Cd) is a widespread soil contaminant that readily accumulates in wheat, and posing a potential threat to human health. Our aim is to investigate Cd toxicity effect and molecular mechanisms for wheat. In this study, the physiological indexes, morphology, and gene expression patterns of diploid wheat (Triticum urartu) seedlings were evaluated after 2 and 5 d of a Cd treatment (10 μM CdSO₄). The Cd treatment resulted in increased proline and glutathione contents in shoots and roots, slight damage to leaf tips, severe damage to root tips, and increased root secretions. Transcriptome analysis showed that there were significantly more differentially expressed genes (DEGs) in shoots and roots after 5 d of Cd stress than after 2 d of Cd stress, and the DEGs of the shoots were more different than the roots. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that the pathways enriched under Cd treatment were "DNA replication" and "phenylpropanoid biosynthesis". These findings provide information about the responses to Cd stress in wheat, and provide a theoretical basis for reducing Cd toxicity and protecting food safety.

One-step separation of the recombinant protein by using the amine-functionalized magnetic mesoporous silica nanoparticles; an efficient and facile approach

The separation process is the main stage of recombinant production. With the advancement of nanotechnology and the development of magnetic nanoparticles, these structures are increasingly used in different applications. In the present study, we produced the recombinant human growth hormone from Pichia pastoris and for protein separation provided the surfaces similar to chromatographic columns on the surface of magnetic nanoparticles. For this purpose, using a co-precipitation method, the core of Fe₃O₄ was prepared and coated by silica. To increase the protein availability, silica mesoporous formation and its amine functionalization were performed. The specific surface area and the pore size were determined 78.3189 m²/g and 7.44 nm. After the magnetic separation, the sample loading in SDS gel shows a reduction in protein band and the protein absorption at a wavelength of 280 nm. Finally, we evaluate the ability of amine functionalized nanoparticles for protein separation that demonstrate the adsorption capacity significantly increased compare with silica-coated nanoparticles. The amine functionalized nanoparticles provide the maximum adsorption capacity of 235.21 μg/mg and after the elution, protein concentration determined 476 mg/L. This work indicates the functionalized magnetic mesoporous silica nanoparticles can be used as the best candidate for the separation of different biological macromolecules.

The comet assay in animal models: From bugs to whales - (Part 2 Vertebrates)

The comet assay has become one of the methods of choice for the evaluation and measurement of DNA damage. It is sensitive, quick to perform and relatively affordable for the evaluation of DNA damage and repair at the level of individual cells. The comet assay can be applied to virtually any cell type derived from different organs and tissues. Even though the comet assay is predominantly used on human cells, the application of the assay for the evaluation of DNA damage in yeast, plant and animal cells is also quite high, especially in terms of biomonitoring. The present extensive overview on the usage of the comet assay in animal models will cover both terrestrial and water environments. The first part of the review was focused on studies describing the comet assay applied in invertebrates. The second part of the review, (Part 2) will discuss the application of the comet assay in vertebrates covering cyclostomata, fishes, amphibians, reptiles, birds and mammals, in addition to chordates that are regarded as a transitional form towards vertebrates. Besides numerous vertebrate species, the assay is also performed on a range of cells, which includes blood, liver, kidney, brain, gill, bone marrow and sperm cells. These cells are readily used for the evaluation of a wide spectrum of genotoxic agents both in vitro and in vivo. Moreover, the use of vertebrate models and their role in environmental biomonitoring will also be discussed as well as the comparison of the use of the comet assay in vertebrate and human models in line with ethical principles. Although the comet assay in vertebrates is most commonly used in laboratory animals such as mice, rats and lately zebrafish, this paper will only briefly review its use regarding laboratory animal models and rather give special emphasis to the increasing usage of the assay in domestic and wildlife animals as well as in various ecotoxicological studies.

Preparation, structural characterization, thermal properties and antifungal activity of alginate-CuO bionanocomposite

In this study, the antifungal activity rate of alginate-CuO bionanocomposite was assessed against Aspergillus niger using colony forming units (CFU) and disc diffusion methods. Employing the Taguchi method, nine experiments were designed for the synthesis of alginate-CuO nanocomposite with the highest antifungal activity. The nanocomposite synthesized under the conditions of experiment 5 (4 mg/mL CuO nanoparticles and 1 mg/mL alginate biopolymer with stirring time of 90 min) showed the greatest inhibition rate on fungal growth (83.17%). In the optimum conditions for the synthesis of alginate-CuO nanocomposite with the highest antifungal activity the second level of CuO NPs (14.14%), alginate biopolymer (8.16%) and stirring time (5.63%) showed the best improvement performance on inhibiting the fungal growth. The results of ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) confirmed the formation of alginate-CuO nanocomposite. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) indicated that the thermal stability of alginate biopolymer and CuO nanoparticles were improved by the formation of the nanocomposite. Due to the favorable properties of alginate-CuO nanocomposite, its antifungal feature can be used in various biomedical fields.

Toxicity responses of different organs of zebrafish (Danio rerio) to silver nanoparticles with different particle sizes and surface coatings

Silver nanoparticles (AgNPs) in aquatic ecosystems are toxic to aquatic organisms. In this study, we aimed to investigate the toxicities and molecular mechanisms of AgNPs with different surface coatings (sodium citrate and polyvinylpyrrolidone) and particle sizes (20 nm and 100 nm) in the gills, intestines, and muscles of zebrafish after 96 h of exposure. Our results indicated that the contribution of particle size to AgNP toxicity was greater than that of the surface coating. Citrate-coated AgNPs were more toxic than polyvinylpyrrolidone-coated AgNPs, and 20-nm AgNPs were more toxic than 100-nm AgNPs. The toxic effects of AgNPs to the tissues were in the order intestines > gills > muscles. Differential expression of genes with the different AgNPs confirmed that they had toxic effects in the zebrafish tissues at the molecular level. Our comprehensive comparison of the toxicities of different AgNPs to aquatic ecosystems will be helpful for further risk assessments of AgNPs.

The impact of morphology and size of zinc oxide nanoparticles on its toxicity to the freshwater microalga, Raphidocelis subcapitata

Microalgae are key test organisms to assess the effects of chemicals on aquatic ecosystems. Zinc oxide nanoparticles (ZnO NPs) as a widely used metal oxide is considered a potential threat to these primary producers at the base of the food chain. This study investigates the toxicity of ZnO NPs, bulk ZnO, and Zn²⁺ to the representative of freshwater microalgae, Raphidocelis subcapitata. To examine the effect of shape and size of nanoparticles, two types of spherical ZnO NPs with different sizes (20 and 40 nm) and two types of rod-shaped ZnO NPs with different lengths (100 and 500 nm) were synthesized. Microalgal cells were exposed to eight concentrations of each ZnO NP type from 0.01 to 0.7 mg/L for 96 h. The results showed that 0.7 mg/L of ZnO NP could completely inhibit algal growth. Size did not interfere with toxicity in spherical ZnO NPs, but the toxicity decreased by increasing the size of rod-shaped ZnO NPs. Spherical ZnO NPs acted more destructive to microalgal cells than nanorod shape. The addition of 0.7 mg/L of ZnO nanorods to samples caused 30% cell death, while 50% cell death was observed by adding the same concentration of nanospherical ZnO. Nano ZnO revealed to be more toxic than bulk ZnO and Zn²⁺. The Zn²⁺ released from dissolution of ZnO NPs was one of the sources of toxicity, but the ZnO nanostructures were also an important factor in the toxicity.

Enhanced performance for Eu(iii) ion remediation using magnetic multiwalled carbon nanotubes functionalized with carboxymethyl cellulose nanoparticles synthesized by plasma technology

Synthesis of sodium carboxymethyl cellulose/iron oxides/MWCNTs composites by a plasma technique and their application to the decontamination of europium ions from aqueous solutions under controlled laboratory conditions.