Sex-dependent and organ-specific toxicity of silver nanoparticles in livers and intestines of adult zebrafish

Mass Spectrometry Imaging Reveals the Morphology-Dependent Toxicological Effects of Nanosilvers on Multiple Organs of Adult Zebrafish (Danio rerio)

Nanosilvers with multifarious morphologies have been extensively used in many fields, but their morphology-dependent toxicity toward nontarget aquatic organisms remains largely unclear. Herein, we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate the toxicological effects of silver nanomaterials with various morphologies on spatially resolved lipid profiles within multiple organs in adult zebrafish, especially for the gill, liver, and intestine. Integrated with histopathology, enzyme activity, accumulated Ag contents and amounts, as well as MSI results, we found that nanosilvers exhibit morphology-dependent nanotoxicity by disrupting lipid levels and producing oxidative stress. Silver nanospheres (AgNSs) had the highest toxicity toward adult zebrafish, whereas silver nanoflakes (AgNFs) exhibited greater toxicity than silver nanowires (AgNWs). Levels of differential phospholipids, such as PC, PE, PI, and PS, were associated with nanosilver morphology. Notably, we found that AgNSs induced greater toxicity in multiple organs, such as the brain, gill, and liver, while AgNWs and AgNFs caused greater toxicity in the intestine than AgNSs. Lipid functional disturbance and oxidative stress further caused inflammation and membrane damage after exposure to nanosilvers, especially with respect to sphere morphology. Taken together, these findings will contribute to clarifying the toxicological effects and mechanisms of different morphologies of nanosilvers in adult zebrafish.

Silver Nanoparticles Encapped by Dihydromyricetin: Optimization of Green Synthesis, Characterization, Toxicity, and Anti-MRSA Infection Activities for Zebrafish (Danio rerio)

To achieve the environmentally friendly and rapid green synthesis of efficient and stable AgNPs for drug-resistant bacterial infection, this study optimized the green synthesis process of silver nanoparticles (AgNPs) using Dihydromyricetin (DMY). Then, we assessed the impact of AgNPs on zebrafish embryo development, as well as their therapeutic efficacy on zebrafish infected with Methicillin-resistant Staphylococcus aureus (MRSA). Transmission electron microscopy (TEM) and dynamic light-scattering (DLS) analyses revealed that AgNPs possessed an average size of 23.6 nm, a polymer dispersity index (PDI) of 0.197 ± 0.0196, and a zeta potential of -18.1 ± 1.18 mV. Compared to other published green synthesis products, the optimized DMY-AgNPs exhibited smaller sizes, narrower size distributions, and enhanced stability. Furthermore, the minimum concentration of DMY-AgNPs required to affect zebrafish hatching and survival was determined to be 25.0 μg/mL, indicating the low toxicity of DMY-AgNPs. Following a 5-day feeding regimen with DMY-AgNP-containing food, significant improvements were observed in the recovery of the gills, intestines, and livers in MRSA-infected zebrafish. These results suggested that optimized DMY-AgNPs hold promise for application in aquacultures and offer potential for further clinical use against drug-resistant bacteria.

Silver nanoparticle ecotoxicity and phytoremediation: a critical review of current research and future prospects

Silver nanoparticles (AgNPs) are widely used in various industries, including textiles, electronics, and biomedical fields, due to their unique optical, electronic, and antimicrobial properties. However, the extensive use of AgNPs has raised concerns about their potential ecotoxicity and adverse effects on the environment. AgNPs can enter the environment through different pathways, such as wastewater, surface runoff, and soil application and can interact with living organisms through adsorption, ingestion, and accumulation, causing toxicity and harm. The small size, high surface area-to-volume ratio, and ability to generate reactive oxygen species (ROS) make AgNPs particularly toxic. Various bioremediation strategies, such as phytoremediation, have been proposed to mitigate the toxic effects of AgNPs and minimize their impact on the environment. Further research is needed to improve these strategies and ensure their safety and efficacy in different environmental settings.

Toxicity assessment of poultry-waste biosynthesized nanosilver in Anabas testudineus (Bloch, 1792) for responsible and sustainable aquaculture development-A multi-biomarker approach

The current study investigates the potential utilization of poultry intestines for the synthesis of stable silver nanoparticles (AgNPs) and their impact on fish physiology. The AgNPs were synthesized and characterized using various analytical techniques. The toxicity of AgNPs on Anabas testudineus was evaluated, determining a 96-h LC50 value of 25.46 mg l-1. Subsequently, fish were exposed to concentrations corresponding to 1/10th, 1/25th, 1/50th, and 1/100th of the estimated LC50 for a duration of 60 days in a sub-acute study. A comprehensive range of biomarkers, including haematological, serum, oxidative stress, and metabolizing markers, were analyzed to assess the physiological responses of the fish. Additionally, histopathological examinations were conducted, and the accumulation of silver in biomarker organs was measured. The results indicate that silver tends to bioaccumulate in all biomarker organs in a dose- and time-dependent manner, except for the muscle tissue, where accumulation initially increased and subsequently decreased, demonstrating the fish's inherent ability for natural attenuation. Analysis of physiological data and integrated biomarker responses reveal that concentrations of 1/10th, 1/25th, and 1/50th of the LC50 can induce stress in the fish, while exposure to 1/100th of the LC50 shows minimal to no stress response. Overall, this study provides valuable insights into the toxicity and physiological responses of fish exposed to poultry waste biosynthesized AgNPs, offering potential applications in aquaculture while harnessing their unique features.

Neurobehavioral disorders induced by environmental zinc in female zebrafish (Danio rerio): Insights from brain and intestine transcriptional and metabolic signatures

Human activities can cause zinc (Zn) contamination of aquatic environments. Zn is an essential trace metal, but effects of environmentally relevant Zn exposure on the brain-intestine axis in fish are poorly understood. Here, six-month-old female zebrafish (Danio rerio) were exposed to environmentally relevant Zn concentrations (0, 1.0, and 1.5 mg/L) for six weeks. Zn significantly accumulated in the brain and intestine, causing anxiety-like behaviors and altered social behaviors. Zn accumulation altered levels of neurotransmitters, including serotonin, glutamate, and γ-aminobutyric acid, in the brain and intestine, and these changes were directly associated with changes in behavior. Zn caused oxidative damage and mitochondrial dysfunction, and impaired NADH dehydrogenase, thereby dysregulating the energy supply in brain Zn exposure resulted in nucleotide imbalance and dysregulation of DNA replication and the cell cycle, potentially impairing the self-renewal of intestinal cells. Zn also disturbed carbohydrate and peptide metabolism in the intestine. These results indicate that chronic exposure to Zn at environmentally relevant concentrations dysregulates the bidirectional interaction of the brain-intestine axis with respect to neurotransmitters, nutrients, and nucleotide metabolites, thereby causing neurological disorder-like behaviors. Our study highlights the necessity to evaluate the negative impacts of chronic environmentally relevant Zn exposure on the health of humans and aquatic animals.

Silver Nanoparticles Cause Neural and Vascular Disruption by Affecting Key Neuroactive Ligand-Receptor Interaction and VEGF Signaling Pathways

Introduction

Silver nanoparticles (AgNP) are widely used as coating materials. However, the potential risks of AgNP to human health, especially for neural and vascular systems, are still poorly understood.

Methods

The vascular and neurotoxicity of various concentrations of AgNP in zebrafish were examined using fluorescence microscopy. In addition, Illumina high-throughput global transcriptome analysis was performed to explore the transcriptome profiles of zebrafish embryos after exposure to AgNP. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to elucidate the top 3000 differentially expressed genes (DEGs) between AgNP-exposed and control groups.

Results

We systematically investigated the neural and vascular developmental toxicities of AgNP exposure in zebrafish. The results demonstrated that AgNP exposure could cause neurodevelopmental anomalies, including a small-eye phenotype, neuronal morphology defects, and inhibition of athletic abilities. In addition, we found that AgNP exposure induces angiogenesis malformation in zebrafish embryos. Further RNA-seq revealed that DEGs were mainly enriched in the neuroactive ligand-receptor interaction and vascular endothelial growth factor (Vegf) signaling pathways in AgNP-treated zebrafish embryos. Specifically, the mRNA levels of the neuroactive ligand-receptor interaction pathway and Vegf signaling pathway-related genes, including si:ch73-55i23.1, nfatc2a, prkcg, si:ch211-132p1.2, lepa, mchr1b, pla2g4aa, rac1b, p2ry6, adrb2, chrnb1, and chrm1b, were significantly regulated in AgNP-treated zebrafish embryos.

Conclusion

Our findings indicate that AgNP exposure transcriptionally induces developmental toxicity in neural and vascular development by disturbing neuroactive ligand-receptor interactions and the Vegf signaling pathway in zebrafish embryos.

Exposure to Nickel Oxide Nanoparticles Induces Alterations in Antioxidant System, Metabolic Enzymes and Nutritional Composition in Muscles of Heteropneustes fossilis

The current study was performed to explore potential toxic effect of nickel oxide nanoparticles (NiO NPs) on muscle tissue of catfish, Heteropneustes fossilis. Fishes were exposed to different concentrations of NiO NPs (12 mg/L, 24 mg/L, 36 mg/L and 48 mg/L) for a period of 14 days. Results revealed that NiO NPs caused significant increase in Ni accumulation, metallothionein content, lipid peroxidation and activity of different antioxidant enzymes (catalase, glutathione s transferase and glutathione reductase) while decrease in activity of superoxide dismutase (p < 0.05). Data also reported induction of Na⁺/K⁺ ATPase activity initially and then its decrease in concentration dependent manner. Fourier transform infrared spectroscopy revealed shift and changes in spectra of muscle of NiO NPs treated fishes. Fluctuations in activity of aspartate amino transferase, alanine amino transferase and alkaline phosphatase were also noticed. Nutritional contents like protein, lipid, and moisture significantly reduced while glucose and ash percent increased.

Using Machine Learning to make nanomaterials sustainable

Sustainable development is a key challenge for contemporary human societies; failure to achieve sustainability could threaten human survival. In this review article, we illustrate how Machine Learning (ML) could support more sustainable development, covering the basics of data gathering through each step of the Environmental Risk Assessment (ERA). The literature provides several examples showing how ML can be employed in most steps of a typical ERA.A key observation is that there are currently no clear guidance for using such autonomous technologies in ERAs or which standards/checks are required. Steering thus seems to be the most important task for supporting the use of ML in the ERA of nano- and smart-materials. Resources should be devoted to developing a strategy for implementing ML in ERA with a strong emphasis on data foundations, methodologies, and the related sensitivities/uncertainties. We should recognise historical errors and biases (e.g., in data) to avoid embedding them during ML programming.

Evaluation of biocidal properties of biodegradable nanofiber filters and their use in face masks

Due to the recent coronavirus-2019 pandemic, several studies have emerged looking for new materials, especially with biocidal characteristics. Thus, the present research investigates the antibacterial properties of biodegradable cellulose acetate (CA) / cetylpyridinium bromide (CPB) electrospun nanofibers, their aerosol filtration, and the possible use as a filter media of surgical face masks. Then, samples of these nanofibers were produced over a nonwoven substrate, using different volumes of polymeric solution during the electrospinning process. The evaluation of the antibacterial properties of the nanofibers was performed for Escherichia coli and Staphylococcus aureus using quantitative methods. The aerosol filtration performance was evaluated in these samples for NaCl nanoparticles (from 7-300 nm) and with 8 mL min^-1 of air flow rate. The results show that the single use of the surfactant has antibacterial properties from a concentration of 39 µg mL^-1 of solution. The nanofibers presented a reduction of 100% for both bacteria. Air filtration tests showed 126.03 and 207.73 Pa cm^-² of pressure drops and 63 and 77% of aerosol filtration efficiency (FE) for samples with 0.13 and 0.15 mL, respectively. Regarding the nanofiber produced with 0.35 mL, the value obtained was 115.13 ± 33.64 Pa cm^-2 and 3.15% of particle penetration. These breathability values are higher than those required for the surgical face mask standard, indicating that improvements in the porosity and thickness are necessary to meet the Brazilian requirements. However, the nanofibers could be applied as filter media for indoor air conditioning systems due to their FE and biocidal properties.

Silver nanoparticles inhibit goatpox virus replication

No effective drugs against goatpox virus (GTPV) exist despite the high morbidity and mortality (up to 100%) caused by this virus. In this study, the antiviral activity of silver nanoparticles (AgNPs) against GTPV, a member of the genus Capripoxvirus, was evaluated. Piper betle leaf extract was used as a reducing agent during the biological synthesis of AgNPs from silver nitrate. The AgNPs were characterized using ultraviolet/visible (UV/vis) absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). AgNPs were tested at different concentrations as antiviral agents against GTPV, and the reduction in the median tissue culture infectious dose (TCID₅₀/mL) was used to quantitate antiviral activity. AgNPs caused significant inhibition of GTPV replication by preventing virus entry into the host cell. Pre-treatment of cells with AgNPs caused a slight reduction in infectivity, but this did not significantly correlate with the effect on virus attachment. AgNPs also appeared to significantly reduce the viral genome copy number. This study demonstrates that the AgNPs are capable of inhibiting GTPV replication in vitro.

Metabolomic responses in livers of female and male zebrafish (Danio rerio) following prolonged exposure to environmental levels of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnONPs) are widespread pollutants that are present in diverse environmental samples. Here, we determined metabolomic and bioenergetic responses in the liver of female and male zebrafish exposed to a prolonged environmentally relevant concentration of ZnONPs. Metabolome analysis revealed that exposure to 500 μg/L ZnONPs reduced the abundance of metabolites in the tricarboxylic acid (TCA) cycle by modulating the activities of rate-limiting enzymes α-ketoglutarate dehydrogenase and isocitrate dehydrogenase. Moreover, oxidative phosphorylation (OXPHOS) was negatively impacted in the liver based upon decreased activities of mitochondrial Complex I and V in both female and male livers. Our results revealed that bioenergetic responses were not attributed to dissolved Zn²⁺ and were not sex-specific. However, the metabolic responses in liver following exposure to ZnONPs did show sex-specific responses. Females exposed to ZnONPs compensated for the energetic stress via increasing fatty acids and amino acids metabolism, while males compensated to ZnONPs exposure by adjusting amino acids metabolism, based upon transcript profiles. This study demonstrates that zebrafish adjust the transcription of metabolic enzymes in the liver to compensate for metabolic disruption following ZnONPs exposure. Taken together, this study contributes to a comprehensive understanding of risks related to ZnONPs exposure in relation to metabolic activity in the liver. Environmental implication Zinc oxide nanoparticles (ZnONPs) are widely used in industry and are subsequently released into environments. However, biological responses between female and male following ZnONPs exposure has never been compared. Our data revealed for the first time that female and male zebrafish showed comparable bioenergetic responses, but different metabolic responses to ZnONPs at an environmentally relevant dose. Females compensated for the energetic stress via increasing fatty acids and amino acids metabolism, while males compensated to ZnONPs exposure by adjusting amino acids metabolism in livers. This study reveals that sex may be an important variable to consider in risk assessments of nanoparticles released into environments.

Assessment of hazardous impact of nickel oxide nanoparticles on biochemical and histological parameters of gills and liver tissues of Heteropneustes fossilis

BACKGROUND

The aim of the present study was to assess the hazardous impact of nickel oxide nanoparticles (NiO NPs) on gills and liver of Heteropneustes fossilis.

METHODS

Fishes were treated with four concentrations of NiO NPs for a period of 14 days. Nickel accumulation, lipid peroxidation, antioxidant enzymes activities (superoxide dismutase, catalase, glutathione s transferase & glutathione reductase), liver enzymes activities (aspartate amino transferase, alanine transaminase, & alkaline phosphatase), Na⁺/K⁺ ATPase activity, FTIR, metallothionein content, ethoxyresorufin-o-deethylase activity, immunohistochemistry, histology and scanning electron microscopy were analyzed in both gills and liver tissues.

RESULTS

Results revealed increased accumulation of nickel in both the tissues of exposed fishes. Lipid peroxidation and activities of different antioxidant enzymes increased (except superoxide dismutase) in both the tissues after exposure. Fluctuations in liver enzymes activities and variation in the activity of Na⁺/K⁺ ATPase were also observed. FTIR data revealed shift in peaks position in both the tissues. Level of metallothionein and its expression as well as activity of ethoxyresorufin-o-deethylase and expression of CYP1A also increased in both the target tissues of treated fishes. Furthermore, histological investigation and scanning electron microscopy showed structural damages in gills as well as liver tissues of exposed fishes.

CONCLUSION

Our results suggest that NiO NPs cause deteriorating effects on the gill and liver tissues of fish, therefore effluents containing these nanoparticles should be treated before their release into water bodies.

Silver nanoparticles induce developmental toxicity via oxidative stress and mitochondrial dysfunction in zebrafish (Danio rerio)

Sliver nanoparticles (AgNPs) are widely used in industry, agriculture, and medicine, potentially resulting in adverse effects on human health and aquatic environments. Here, we investigated the developmental toxicity of zebrafish embryos with acute exposure to AgNPs. Our results demonstrated developmental defects in 4 hpf zebrafish embryos after exposure to different concentrations of AgNPs for 72 h. In addition, RNA-seq profiling of zebrafish embryos after AgNPs treatment. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the differentially expressed genes (DEGs) were enriched in DNA replication initiation, oxidoreductase activity, DNA replication, cellular senescence, and oxidative phosphorylation signaling pathways in the AgNPs-treated group. Notably, we also found that AgNPs exposure could result in the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), the inhibition of superoxide dismutase (SOD), catalase (CAT), and mitochondrial complex I-V activities, and the downregulated expression of SOD, CAT, and mitochondrial complex I-IV chain-related genes. Moreover, the expression of mitochondrion-mediated apoptosis signaling pathway-related genes, such as bax, bcl2, caspase-3, and caspase-9, was significantly regulated after AgNPs exposure in zebrafish. Therefore, these findings demonstrated that AgNPs exposure could cause oxidative stress, induce mitochondrial dysfunction, and ultimately lead to developmental toxicity.

Exploring the Potential of Metal Nanoparticles as a Possible Therapeutic Adjunct for Covid-19 Infection

The WHO has declared the Covid-19 outbreak as a global health emergency with a mortality rate of approximately 3%, across 200 countries. There has been a considerable risk involved with drug repurposing in Covid-19 treatment, particularly in patients with underlying chronic disorders. Intervention of appropriate adjunct to primary drug therapy at subclinical or clinical doses may help to reduce unintended consequences involved in Covid-19 therapy. Metal nanoparticles due to their intrinsic structural and functional properties, not only contribute to anti-viral properties but also help to reduce the risk for associated complications. Although, silver nanoparticles hold great promise as an effective biocidal agent, while other metal nanoparticles also fueled interest against virus infection. The present review discusses the important properties of selected metal nanoparticles, their antiviral principle with possible toxic consequences, provides invaluable information for scientists and clinicians about an appropriate metal nanoparticle as an adjunct for Covid-19 treatment.

Zinc alters behavioral phenotypes, neurotransmitter signatures, and immune homeostasis in male zebrafish (Danio rerio)

Anthropogenic activities discharge zinc into aquatic ecosystems, and the effects of long-term and low-concentration zinc exposure on fish behavior are unclear. We evaluated the behavior and physiology of male zebrafish (Danio rerio) after a 6-week exposure to 1.0 or 1.5 ppm (mg/L) zinc chloride. The exposure caused anxiety-like behaviors and altered the social preferences in both exposure groups. Analysis of transcriptional changes suggested that in the brain, zinc exerted heterogenetic effects on immune and neurotransmitter functions. Exposure to 1.0 ppm zinc chloride resulted in constitutive immune dyshomeostasis, while exposure to 1.5 ppm zinc chloride impaired the neurotransmitter glutamate. In the intestine, zinc dysregulated self-renewal of intestinal cells, a potential loss of defense function. Moreover, exposure to 1.5 ppm zinc chloride suppressed intestinal immune functions and dysregulated tyrosine metabolism. These behavioral alterations suggested that the underlying mechanisms were distinct and concentration-specific. Overall, environmental levels of zinc can alter male zebrafish behaviors by dysregulating neurotransmitter and immunomodulation signatures.

Exposure to atmospheric Ag, TiO2, Ti and SiO2 engineered nanoparticles modulates gut inflammatory response and microbiota in mice

The development of nanotechnologies is leading to greater abundance of engineered nanoparticles (EN) in the environment, including in the atmospheric air. To date, it has been shown that the most prevalent EN found in the air are silver (Ag), titanium dioxide (TiO₂), titanium (Ti), and silicon dioxide (SiO₂). As the intestinal tract is increasingly recognized as a target for adverse effects induced by inhalation of air particles, the aim of this study was to assess the impact of these 4 atmospheric EN on intestinal inflammation and microbiota. We assessed the combined toxicity effects of Ag, Ti, TiO₂, and SiO₂ following a 28-day inhalation protocol in male and female mice. In distal and proximal colon, and in jejunum, EN mixture inhalation did not induce overt histological damage, but led to a significant modulation of inflammatory cytokine transcript abundance, including downregulation of Tnfα, Ifnγ, Il1β, Il17a, Il22, IL10, and Cxcl1 mRNA levels in male jejunum. A dysbiosis was observed in cecal microbiota of male and female mice exposed to the EN mixture, characterized by sex-dependent modulations of specific bacterial taxa, as well as sex-independent decreased abundance of the Eggerthellaceae family. Under dextran sodium sulfate-induced inflammatory conditions, exposure to the EN mixture increased the development of colitis in both male and female mice. Moreover, the direct dose-response effects of individual and mixed EN on gut organoids was studied and Ag, TiO₂, Ti, SiO₂, and EN mixture were found to generate specific inflammatory responses in the intestinal epithelium. These results indicate that the 4 most prevalent atmospheric EN could have the ability to disturb intestinal homeostasis through direct modulation of cytokine expression in gut epithelium, and by altering the inflammatory response and microbiota composition following inhalation.

From carrion-eaters to plastic material plunderers: Toxicological impacts of plastic ingestion on black vultures, Coragyps atratus (Cathartiformes: Cathartidae)

Despite plastic ingestion has already been reported in several bird species, its physiological impacts have been little inspected, especially in representatives of the Cathartidae family. Thus, in this study, we aimed to identify, characterize, and evaluate the effects arising from the ingestion of plastic materials by Coragyps atratus adults, that captured in landfill areas. Herein, a total of 51 individuals were captured, the frequency of plastic intake being higher than 40%. The plastic materials consisted mainly of low-density polyethylene and film-type polystyrene, as well as presenting irregular shapes and diameters between 10 and 30 mm. Biochemically, we observed in animals that contained plastics in the stomach ("plastic" group) high production of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) - especially in the intestine, muscle and brain - whose activity of catalase (CAT) and superoxide dismutase (SOD) was not sufficient to counteract the oxidative stress. Moreover, in the liver of these same animals, we observed high production of nitrite and nitrate, suggesting a hepatic nitrosative stress. Plus, we observed a cholinesterase effect in animals from the "plastic" group, marked by increased activity of butyrylcholinesterase (BChE) (in the brain) and muscle and cerebral acetylcholinesterase (AChE). On the other hand, the biochemical changes perceived were not significantly correlated with the identified plastic material concentrations (2.808 ± 0.598 items/g of stomach content and 0.276 ± 0.070 items/g of stomach - fresh weight), body condition of the animals, size, and shape of the identified plastic materials. Hence, our study sheds the light on the toxicity of plastics deposited in landfills and their ingestion by C. atratus, which reinforces the hypothesis that these materials are harming the health of these birds and, consequently, the dynamics of their populations.

Resistance and Resilience of Fish Gut Microbiota to Silver Nanoparticles

Understanding mechanisms governing the resistance and resilience of microbial communities is essential for predicting their ecological responses to environmental disturbances. Although we have a good understanding of such issues for soil and lake ecosystems, how ecological resistance and resilience regulate the microbiota in the fish gut ecosystem remains unclear. Using the zebrafish model, we clarified the potential mechanisms governing the gut microbiota after exposure to silver nanoparticles (AgNPs). Here, we explored the ecological resistance and resilience of gut microbiota in zebrafish exposed to different concentrations of AgNPs (i.e., 10, 33 and 100 μg/liter) for 15, 45, 75 days. The high-throughput sequencing analysis of the 16S rRNA gene showed that AgNP exposure significantly reduced the α-diversity of gut microbiota and resulted in obvious dynamics of community composition and structure. However, the rebound of zebrafish gut microbiota was pushed toward an alternative state after 15 days of AgNP exposure. We found that homogeneous selection was a more prevalent contributor in driving gut community recovery after AgNP exposure. The resilience and resistance of gut microbiota responses to AgNP disturbance might be mainly determined by the predominant keystone taxa such as Acinetobacter and Gemmata. This study not only expanded our understanding of fish gut microbiota's responses to pollutants but also provided new insights into maintaining host-microbiome stability during environmental perturbations. IMPORTANCE Understanding the ecological mechanisms governing the resistance and resilience of microbial communities is a key issue to predict their responses to environmental disturbances. Using the zebrafish model, we wanted to clarify the potential mechanisms governing the resistance and resilience of gut microbiota after exposure to silver nanoparticles (AgNPs). We found that AgNP contamination significantly reduced the α-diversity of gut microbiota and resulted in obvious changes in community composition. The resilience and resistance of gut microbiota to AgNPs might be associated with the predominant keystone taxa (e.g., Acinetobacter and Gemmata). This study greatly expanded our understanding of how fish gut microbiota responds to environmental perturbations and maintains stability.

Efficacy and side effects of bio-fabricated sardine fish scale silver nanoparticles against malarial vector Anopheles stephensi

Mosquitoes are a great menace for humankind since they transmit pathogenic organisms causing Malaria, Dengue, Chikungunya, Elephantiasis and Japanese encephalitis. There is an urgent need to discover new and novel biological tools to mitigate mosquito-borne diseases. To develop bioinsecticides through newly developed nanotechnology is another option in the present research scenario. In this study we synthesize and characterize sardine fish scales with silver nitrate by adopting various instrumental techniques such as UV- and FTIR-spectroscopy, energy-dispersive X-ray (EDAX), X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). Toxicity bioassays were conducted with young developmental stages of mosquito vectors. Significant mortality appeared after different life stages of mosquito vectors (young larval and pupal instars were exposed to the nanomaterials). LC50 values were 13.261 ppm for young first instar larvae and 32.182 ppm for pupae. Feeding and predatory potential of G. affinis, before and after exposure to nanoparticles against mosquito larval (I & II) instars of the mosquitoes showed promising results in laboratory experiments. Feeding potential of mosquito fish without nanoparticle treatment was 79.7% and 70.55% for the first and second instar larval populations respectively. At the nanoparticle-exposed situation the predatory efficiency of mosquitofish was 94.15% and 84.3%, respectively. Antioxidant enzymes like (SOD), (CAT), and (LPO) were estimated in the gill region of sardine fish in control and experimental waters. A significant reduction of egg hatchability was evident after nanoparticle application. It became evident from this study that the nano-fabricated materials provide suitable tools to control the malaria vector Anopheles stephensi in the aquatic phase of its life cycle. This finding suggests an effective novel approach to mosquito control.

Metabolic profiling of nanosilver toxicity in the gills of common carp

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.

New insights into bisphenols induced obesity in zebrafish (Danio rerio): Activation of cannabinoid receptor CB1

Bisphenols (BPs), as widely used plastic additives, penetrate into our daily lives. BPs are considered endocrine disruptors and could potentially induce obesity. In this study, the effects of bisphenol A (BPA) and tetrabromobisphenol A (TBBPA) on food intake and lipid metabolism in zebrafish were determined. Moreover, the impact of BPA and TBBPA on the endocannabinoid system (ECS) of zebrafish was further explored by metabolomics, transcriptomics, and molecular docking analysis. Here we show that exposure to BPA and TBBPA at concentrations commonly found in the environment (20, 100, and 500 μg/L) led to hyperphagia and obesity in adult male zebrafish. Metabolomics and histopathological analysis revealed significant lipid accumulation in the liver of zebrafish exposed to BPA and TBBPA. The expression of ECS-related genes, in conjunction with RNA-Seq results, further indicated that BPA and TBBPA increased appetite and induced obesity by activating cannabinoid receptor type 1(CB1). Furthermore, molecular docking revealed that six representative BPs including BPA and TBBPA could bind to the CB1 receptor. Collectively, these findings indicate that CB1 may be a potential target for BPs to induce obesity.

The role of sex as a biological variable in the efficacy and toxicity of therapeutic nanomedicine

Males and females have physiological, hormonal, and genetic differences that can cause different responses to medicinal treatments. The role of sex in the pharmacokinetics and pharmacodynamics of drugs is well established in the literature. However, researchers have yet to robustly and consistently consider the impact of sex differences on the pharmacokinetics and pharmacodynamics of nanomedicine formulations when designing nanomedicine therapeutics and/or constructing clinical trials. In this review, we highlight the physiological and anatomical differences between sexes and discuss how these differences can influence the therapeutic efficacy, side effects, and drug delivery safety of nanomedicine products. A deep understanding of the effects of sex on nano-based drug delivery agents will robustly improve the risk assessment process, resulting in safer formulations, successful clinical translation, and improved therapeutic efficacies for both sexes.

Synthesis and characterization of palladium nanoparticles by chemical and green methods: A comparative study on hepatic toxicity using zebrafish as an animal model

Nanoparticles synthesized by chemical methods are of a matter of concern, whereas, the green methods are said to be eco-friendly and environmentally safe. In this study, the toxicity of palladium nanoparticles (Pd NPs) synthesized through chemical co-precipitation and green route method using Annona squamosa seed kernels (As-Pd NPs) were evaluated using zebrafish as an animal model. The synthesized nanoparticles (NPs) were characterized using UV-Visible spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray (EDX), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS) and Zeta potential. Zebrafish (Danio rerio) were exposed to 0.4 ng/L of Pd NPs and As-Pd NPs for 96-h, further oxidative stress parameters and histological changes were evaluated. The superoxide dismutase (SOD), catalase (CAT) activity and the lipid peroxidation (LPO) levels were elevated in the Pd NPs groups. But in the As-Pd NPs group, the SOD activity showed a biphasic nature while the CAT activity gradually declined till the 96-h compared to the control and Pd NPs groups. The LPO levels in the As-Pd NPs groups showed a measurable increase till 72-h and sudden decline at the end of 96-h. Anomalies in the histological changes such as ruptured hepatocytes, sinusoidal congestion, vacuolation and accumulation of erythrocytes were observed in both the NPs treated groups but As-Pd NPs exhibited lesser lesions than the control and Pd NPs groups. However, our present study reveals the possible reliability of the nanoparticles and the mechanism of scavenging activity suggesting that the As-Pd NPs synthesized by green route are less toxic comparing to the chemically synthesized Pd NPs.

In vivo evaluation of Nano-palladium toxicity on larval stages and adult of zebrafish (Danio rerio)

The existence and usage of nano-sized palladium (nano-Pd) as catalytic promoters among industries and researchers have been laid a way to explore the release of nano-Pd particles into the aquatic environment, bio-accumulating in living organisms. However, the data on fate and toxicity in response to nano-Pd on aquatic organisms are very limited. Herein, we report the concentration-specific toxicity of nano-Pd in zebrafish (Danio rerio). Nano-Pd was synthesized and characterized by Field Emission Scanning Electron Microscopy (FE-SEM), Dynamic Light Scattering (DLS) and Zeta potential. To determine the in vivo toxicity of nano-Pd, the 96 hpf larvae and the adult zebrafish were treated with two (22 and 0.4 ng/L) environmental relevant concentrations. High doses of nano-Pd influenced the hatching rate, embryo survival, heartbeat and teratological anomalies in the 96 hpf larvae. Reactive oxygen species (ROS) and apoptosis were also influenced by nano-Pd exposure while the acetylcholinesterase (AChE) activity was declined in a dose dependent manner. In long-term exposure (42 days), the adult fish showed erratic movements in swimming pattern inhibiting the AChE activity in both the concentrations of brain and liver. The antioxidant enzyme activity such as superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR) and lipid peroxidation (LPO), showed a significant change (P < 0.05) indicating that oxidative stress was induced by nano-Pd. Similarly, nano-Pd also induced histopathological lesions in gill, liver and brain providing an insight of fate and toxicity of nano-Pd in the aquatic environment. Our study contributes a significant mechanism to understand the toxicity concern of nano-Pd in the aquatic environment.

Modulation of Innate Immune Toxicity by Silver Nanoparticle Exposure and the Preventive Effects of Pterostilbene

Silver nanoparticles pose a potential risk to ecosystems and living organisms due to their widespread use in various fields and subsequent gradual release into the environment. Only a few studies have investigated the effects of silver nanoparticles (AgNPs) toxicity on immunological functions. Furthermore, these toxic effects have not been fully explored. Recent studies have indicated that zebrafish are considered a good alternative model for testing toxicity and for evaluating immunological toxicity. Therefore, the purpose of this study was to investigate the toxicity effects of AgNPs on innate immunity using a zebrafish model and to investigate whether the natural compound pterostilbene (PTE) could provide protection against AgNPs-induced immunotoxicity. Wild type and neutrophil- and macrophage-transgenic zebrafish lines were used in the experiments. The results indicated that the exposure to AgNPs induced toxic effects including death, malformation and the innate immune toxicity of zebrafish. In addition, AgNPs affect the number and function of neutrophils and macrophages. The expression of immune-related cytokines and chemokines was also affected. Notably, the addition of PTE could activate immune cells and promote their accumulation in injured areas in zebrafish, thereby reducing the damage caused by AgNPs. In conclusion, AgNPs may induce innate immune toxicity and PTE could ameliorate this toxicity.

Recent Advancement in Nanotechnology-Based Drug Delivery System Against Viral Infections

In the last few decades, the exponential rise in the incidence of viral infections sets a global health emergency across the world. The biomimetic architecture, the ability to hijack host immune responses, continuous antigen shifting, and drafting are the major critical factors that are responsible for the unavailability of a concrete therapeutic regimen against viral infections. Further, inappropriate pharmacodynamic physicochemical and biological parameters such as low aqueous solubility, poor permeability, high affinity for plasm proteins, short biological half-lives, and fast elimination from the systemic circulation are the major critical factors that govern the suboptimal drug concentration at the target site that leads to the development of drug resistance. To address this issue, nanotechnology-based drug delivery approach is emerged as an altering method to attain the optimal drug concentration at the target site for a prolonged period by integrating the nanoengineering tools in the synthesis of nanoparticles. Nanodimensional configuration with enhanced permeability and retention effect, increased surface-area-to-volume ratio, provision for surface functionalization, etc., are the privileged aspects that make it an effective drug delivery system for dispensing the antiviral therapeutics. However, size, shape, charge, and surface topology of nanoparticles are the greater influential factors that determine target-specific drug delivery, optimum cellular uptake, degree of opsonization by the host immune cells, drug retention time, transcytosis, the extension of biological half-life, in vivo stability, and cytotoxicity. The review will enlighten the elaborative role of nanotechnology-based drug delivery and the major challenging aspect of clinical safety and efficacy.

Nanoparticle-Based Devices in the Control of Antibiotic Resistant Bacteria

Antimicrobial resistance (AR) is one of the most important public health challenges worldwide as it represents a serious complication that is able to increase the mortality, morbidity, disability, hospital stay and economic burden related to infectious diseases. As such, the spread of AR–pathogens must be considered as an emergency, and interdisciplinary approaches must be undertaken in order to develop not only drugs, but holistic strategies to undermine the epidemic and pathogenic potentials of multi-drug resistant (MDR) pathogens. One of such approaches has focused on the use of antimicrobial nanoparticles (ANPs), as they have demonstrated to possess strong antimicrobial effects on MDR pathogens. On the other hand, the ability of bacteria to develop resistance to such agents is minimal. In this way, ANPs may seem a good choice for the development of new drugs, but there is no certainty about their safety, which may delay its translation to the clinical setting. As MDR pathogens are quickly becoming more prevalent and drug development is slow and expensive, there is an increasing need for the rapid development of new strategies to control such agents. We hereby explore the possibility of designing ANP-based devices such as surgical masks and fabrics, wound dressings, catheters, prostheses, dentifrices, water filters, and nanoparticle-coated metals to exploit the potential of such materials in the combat of MDR pathogens, with a good potential for translation into the clinical setting.

Silver nanoparticles-induced nephrotoxicity in rats: the protective role of red beetroot (Beta vulgaris) juice

The present study was designed to investigate the nephrotoxicity of silver nanoparticles (AgNPs; 80 mg/kg; > 100 nm) and to evaluate the protective effect exercised by Beta vulgaris (beetroot) juice (RBR; 200 mg/kg) on male rats' kidney. Serum-specific parameters (urea, creatinine, electrolytes and histopathology of kidney tissue) were examined to assess the AgNPs nephrotoxicity effect. Moreover, this study analysed oxidative stress (lipid peroxidation, glutathione, superoxide dismutase and catalase) and anti-apoptotic markers (Bcl-2). AgNPs intoxication increased kidney function marker levels and lipid peroxidation and decreased the glutathione, superoxide dismutase and catalase activities in kidney tissue. Additionally, Bcl-2 expression was downregulated following AgNPs intoxication. Moreover, AgNPs induced a significant increase in renal DNA damage displayed as an elevation in tail length, tail DNA percentage and tail moment. Interestingly, RBR post-treatment restored the biochemical and histological alterations induced by AgNPs exposure, reflecting its nephroprotective effect. Collectively, the present data suggest that RBR could be used as a potential therapeutic intervention to prevent AgNPs-induced nephrotoxicity.