Comparative evaluation of impact of Zn and ZnO nanoparticles on brine shrimp (Artemia salina) larvae: effects of particle size and solubility on toxicity

GABA attenuates neurotoxicity of zinc oxide nanoparticles due to oxidative stress via DAF-16/FoxO and SKN-1/Nrf2 pathways

Zinc oxide nanoparticles (ZnO-NPs) are one of the most widely used metal oxide nanomaterials. The increased use of ZnO-NPs has exacerbated environmental pollution and raised the risk of neurological disorders in organisms through food chains, and it is urgent to look for detoxification strategies. γ-Aminobutyric acid (GABA) is an inhibitory neurotransmitter that has been shown to have anxiolytic, anti-aging and inhibitory effects on nervous system excitability. However, there are few reports on the prevention and control of the toxicity of nano-metal ions by GABA. In zebrafish, ZnO-NPs exposure led to increased mortality and behavioral abnormalities of larva, which could be moderated by GABA intervention. Similar results were investigated in Caenorhabditis elegans, showing lifespan extension, abnormal locomotor frequency and behavior recovery when worms fed with GABA under ZnO-NPs exposure. Moreover, GABA enhanced antioxidant enzyme activities by upregulating the expression of antioxidant-related genes and thus scavenged excessive O2-. In the case of ZnO-NPs exposure, inhibition of nuclear translocation of DAF-16 and SKN-1 was restored by GABA. Meanwhile, the protective effect of GABA was blocked in daf-16 (-) and skn-1 (-) mutant, suggesting that DAF-16/FoxO and SKN-1/Nrf2 pathways is the key targets of GABA. This study provides a new solution for the application of GABA and mitigation of metal nanoparticle neurotoxicity.

Bioactive Potential of Olive Mill Waste Obtained from Cultivars Grown in the Island of Malta

This study explores the bioactive potential of olive mill waste derived from cultivars grown in the Maltese Islands through various analytical approaches. Cell culture, cell staining, allelopathic assays, shrimp brine lethality assays, and HPLC analysis were conducted to assess the efficacy and bioactivity of the extracts using different treatments, including methanolic extraction, acid, and alkaline hydrolysis. Notably, the results from cell lines revealed that NB4r2 cells exhibited high susceptibility to the tested extracts, with the lowest IC50 recorded after 72 h of exposure. Notably, the 'Bajda' cultivar displayed the most effectiveness, particularly with acid hydrolysis. In allelopathic assays, higher concentrations of 'Malti', 'Bidni', and 'Bajda' extracts significantly inhibited lettuce seed germination. Similarly, in the brine shrimp lethality assay, higher concentrations led to increased mortality rates of Artemia salina, though rates decreased at lower concentrations. The identification of phenolic compounds found in olive mill waste was conducted using high-performance liquid chromatography (HPLC) with the use of internal standards. The identification revealed a variety of compounds, with 3-hydroxytyrosol and oleacein being present in high abundance in nearly all hydrolyzed and methanolic extracts, whereas gallic acid was found to be the least abundant. These findings highlight the rich bioactive potential of olive mill waste and provide insights into its applications in pharmaceuticals, nutraceuticals, and agriculture, emphasizing the importance of further research to fully exploit these valuable resources.

Synthesis, Characterization, and Ecotoxicology Assessment of Zinc Oxide Nanoparticles by In Vivo Models

The widespread use of zinc oxide nanoparticles (ZnO NPs) in multiple applications has increased the importance of safety considerations. ZnO NPs were synthesized, characterized, and evaluated for toxicity in Artemia salina and zebrafish (Danio rerio). NPs were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The hydrodynamic size and stability of the ZnO NP surface were examined using a Zetasizer. Characterization techniques confirmed the ZnO wurtzite structure with a particle size of 32.2 ± 5.2 nm. Synthesized ZnO NPs were evaluated for acute toxicity in Artemia salina using the Probit and Reed and Muench methods to assess for lethal concentration at 50% (LC50). The LC50 was 86.95 ± 0.21 μg/mL in Artemia salina. Physical malformations were observed after 96 h at 50 μg/mL of exposure. The total protein and cytochrome P450 contents were determined. Further analysis was performed to assess the bioaccumulation capacity of zebrafish (Danio rerio) using ICP-OES. ZnO NP content in adult zebrafish was greater in the gastrointestinal tract than in the other tissues under study. The present analysis of ZnO NPs supports the use of Artemia salina and adult zebrafish as relevant models for assessing toxicity and bioaccumulation while considering absorption quantities.

Subacute toxicity and endocrine-disrupting effects of Fe2O3, ZnO, and CeO2 nanoparticles on amphibian metamorphosis

This study evaluated the potential toxic and endocrine-disrupting effects of sublethal concentrations of Fe2O3, CeO2 and ZnO nanoparticles (NPs) on amphibian metamorphosis. Tadpoles were exposed to several NPs concentrations, reaching a maximum of 1000 µg/L, for up to 21 days according to the amphibian metamorphosis assay (AMA). Some standard morphological parameters, such as developmental stage (DS), hind limb length (HLL), snout-to-vent length (SVL), wet body weight (WBW), and as well as post-exposure lethality were recorded in exposed organisms on days 7 and 21 of the bioassay. Furthermore, triiodothyronine (T3), thyroxine (T4) and malondialdehyde (MDA) levels and the activities of glutathione S-transferases (GST), glutathione reductase (GR), catalase (CAT), carboxylesterase (CaE), and acetylcholinesterase (AChE) were determined in exposed tadpoles as biomarkers. The results indicate that short-term exposure to Fe2O3 NPs leads to toxic effects, both exposure periods cause toxic effects and growth inhibition for ZnO NPs, while short-term exposure to CeO2 NPs results in toxic effects and long-term exposure causes endocrine-disrupting effects. The responses observed after exposure to the tested NPs during amphibian metamorphosis suggest that they may have ecotoxicological effects and their effects should be monitored through field studies.

Assessing toxicity mechanism of silver nanoparticles by using brine shrimp (Artemia salina) as model

The acute toxicity of silver nanoparticles (AgNPs) in Artemia salina is primarily attributed to the interaction between silver ions (Ag+) and chitin, which constitutes the main structural component of the organism's cuticle. To investigate this interaction and gain a deeper understanding of its nature, geometric optimization calculations and symmetry-adapted perturbation theory (SAPT0) analysis were performed. These calculations aimed to determine the most favorable conformation based on the binding energies of silver ions with chitin and to elucidate the underlying mechanisms of their interaction. The results indicate an ionic effect dependent on the ion state, with simulations revealing that Ag3+ ions have the potential to cause significant deformation of the chitin structure. Furthermore, this study evaluated the behavior of AgNPs using nauplii of A. salina instar I, assessing both mortality rates and cell damage. Toxicity of AgNPs was observed in A. salina at concentrations of 50 and 100 ppm within a timeframe of 24-48 h. The toxicity of AgNPs can be attributed to their interaction with the cuticle and subsequent modification of the chitin structure through the binding of ionic silver. Light microscopy (LM) analysis confirmed the presence of AgNPs in the cuticle, while confocal laser scanning microscopy (CLSM) revealed cellular damage. In addition, this research offers new perspectives on the toxicity mechanism of AgNPs by introducing a novel model that explores the interaction of silver ions with the cuticle of A. salina. These insights are derived from a combination of atomistic models and ecotoxicology assays.

Toxicity Evaluation, Plant Growth Promotion, and Anti-fungal Activity of Endophytic Bacteria-Mediated Silver Nanoparticles

In recent years, the uses of silver nanoparticles have increased, which lead to nanoparticles discharge into aquatic bodies which may, if not well controlled, have harmful effect on different organisms. This calls for the need to constantly evaluate the toxicity level of nanoparticles. In this study, green biosynthesized silver nanoparticles mediated by endophytic bacteria Cronobacter sakazakii (CS-AgNPs) were subjected to toxicity evaluation by brine shrimp lethality assay. The ability of CS-AgNPs to improve plant growth by nanopriming of Vigna radiata L seeds treated with different concentrations (1ppm, 2.5ppm, 5ppm and 10ppm) in order to enhance biochemical constituents was investigated, also its inhibitory effect to growth of phytopathogenic fungi Mucor racemose was examined. Results showed that Artemia salina treated with CS-AgNPs exhibited good hatching percentage and LC50 value of 688.41 µg/ml when Artemia salina eggs were exposed to CS-AgNPs during hatching. Plant growth was enhanced at 2.5ppm CS-AgNPs, with increased photosynthetic pigments, protein, and carbohydrate content. This study suggests that silver nanoparticles synthesized via endophytic bacteria Cronobacter sakazakii are safe to use and can be utilized as means of combating plant fungal pathogens.

Oxidative Stress and Neurotoxicity of Cadmium and Zinc on Artemia franciscana

Despite not being redox-active metals, Cd and Zn can disrupt cellular redox homeostasis by acting pro-oxidatively. The aim of this study was to examine the effects of exposure to Zn (14 and 72 mg/L) and Cd (7.7 and 77 mg/L) for 24 and 48 h on oxidative and antioxidative parameters and the activity of glutathione-S-transferase in Artemia franciscana tissue. In addition, the neurotoxicity of the metals was examined by determining the activity of acetylcholinesterase (AChE). In A. franciscana tissue, Cd (0.0026 ± 0.0001 mg/L) was detected only after 48 h of exposure to 77 mg/L Cd. After 24 h, the 14- and 72-mg/L Zn treatments resulted in significant increases in the Zn concentration (0.54 ± 0.026 mg/L (p < 0.01) and 0.68 ± 0.035 (p < 0.0001), respectively) in A. franciscana tissue compared with the control level, and significant increases were also detected after 48 h (0.59 ± 0.02 (p < 0.0001) and 0.79 ± 0.015 (p < 0.0001), respectively). The malondialdehyde (MDA) concentration in the metal-treated samples was increased after 24 h of exposure, whereas after 48 h, an increase in the MDA concentration was detected only with 7.7. mg/L Cd. A significant increase in the H₂O₂ concentration after 24 h was measured only after treatment with 72 mg/L Zn. The treatment with 7.7 mg/L Cd for 24 h induced a significant increase in the AChE activity, whereas 48 h of treatment with 77 mg/L Cd and 14 mg/L Zn significantly inhibited AChE. The results indicate that lipid peroxidation resulting from metal toxicity may constitute the basis of neurotoxicity.

What function of nanoparticles is the primary factor for their hyper-toxicity?

Nanomaterials have applications in environmental protection, hygiene, medicine, agriculture, and the food industry due to their enhanced bio-efficacy/toxicity as science and technology have progressed, notably nanotechnology. The extension in the use of nanoparticles in day-to-day products and their excellent efficacy raises worries about safety concerns associated with their use. Therefore, to understand their safety concerns and find the remedy, it is imperative to understand the rationales for their enhanced toxicity at low concentrations to minimize their potential side effects. The worldwide literature quotes different nanoparticle functions responsible for their enhanced bio-efficacy/ toxicity. Since the literature on the comparative toxicity study of nanoparticles of different shapes and sizes having different other physic-chemical properties like surface areas, surface charge, solubility, etc., evident that the nanoparticle's toxicity is not followed the fashion according to their shape, size, surface area, surface charge, solubility, and other Physico-chemical properties. It raises the question then what function of nanoparticle is the primary factor for their hyper toxicity. Why do non-spherical and large-sized nanoparticles show the same or higher toxicity to the same or different cell line or test organism instead of having lower surface area, surface charge, larger size, etc., than their corresponding spherical and smaller-sized nanoparticles? Are these factors a secondary, not primary, factor for nanoparticles hyper-toxicity? If so, what function of nanoparticles is the primary function for their hyper-toxicity? Therefore, in this article, literature related to the comparative toxicity of nanoparticles was thoroughly studied, and a hypothesis is put forth to address the aforesaid question, that the number of atoms/ions/ molecules per nanoparticles is the primary function of nanoparticles toxicity.

Green synthesis of silver nanoparticles from Cassia Auriculata: Targeting antibacterial, antioxidant activity, and evaluation of their possible effects on saltwater microcrustacean, Artemia Nauplii (non-target organism)

Due to their huge surface area to volume ratio, metallic nanoparticles are becoming increasingly important in numerous spheres of life. Here, initially, we aimed to evaluate the potential use of Cassia auriculata (CA) extract to synthesize silver nanoparticles (AgNPs). Then, we evaluated its antimicrobial potential and antioxidant capacity, as well as performed in silico analysis, and investigated the possible non-toxic effect of AgNPs on Artemia nauplii. Fourier transform infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM/TEM), energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), and dynamic light scattering (DLS) studies were used to characterize the biosynthesized AgNPs. Our data indicate that Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus bacteria were susceptible to the biosynthesized AgNPs, whose effect was concentration-response. With a ZOI of 10 mm, the AgNPs were most efficient against gram-positive B. cereus bacteria at the highest concentration (75 μg/mL). The biosynthesized AgNPs (at 25 to 125 μg/mL) showed good antioxidant activity in the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and FRAP (ferric reducing antioxidant power) assays. Oleanolic acid from CA exhibited strong binding affinity and high binding energy to E. coli and B. cereus (-9.66 and - 9.74 kcal/mol) on in silico research. According to the comparative non-toxicity analysis, AgNPs, AgNO₃, and CA bark extract had the least toxic effects on A. nauplii, with respective mortality rates of 28.14, 32.26, and 38.42 %, respectively. In conclusion, the current work showed that AgNPs produced from CA bark could be a promising material for diverse applications.

Phytofabrication and Characterisation of Zinc Oxide Nanoparticles Using Pure Curcumin

Zinc oxide and curcumin, on their own and in combination, have the potential as alternatives to conventional anticancer drugs. In this work, zinc oxide nanoparticles (ZnO NPs) were prepared by an eco-friendly method using pure curcumin, and their physicochemical properties were characterised. ATR-FTIR spectra confirmed the role of curcumin in synthesising zinc oxide curcumin nanoparticles (Green-ZnO-NPs). These nanoparticles exhibited a hexagonal wurtzite structure with a size and zeta potential of 27.61 ± 5.18 nm and -16.90 ± 0.26 mV, respectively. Green-ZnO-NPs showed good activity towards studied bacterial strains, including Escherichia coli, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. The minimum inhibitory concentration of Green-ZnO-NPs was consistently larger than that of chemically synthesised ZnO NPs (Std-ZnO-NPs) or mere curcumin, advocating an additive effect between the zinc oxide and curcumin. Green-ZnO-NPs demonstrated an efficient inhibitory effect towards MCF-7 cells with IC50 (20.53 ± 5.12 μg/mL) that was significantly lower compared to that of Std-ZnO-NPs (27.08 ± 0.91 μg/mL) after 48 h of treatment. When Green-ZnO-NPs were tested against Artemia larvae, a minimised cytotoxic effect was observed, with LC50 being almost three times lower compared to that of Std-ZnO-NPs (11.96 ± 1.89 μg/mL and 34.60 ± 9.45 μg/mL, respectively). This demonstrates that Green-ZnO-NPs can be a potent, additively enhanced combination delivery/therapeutic agent with the potential for anticancer therapy.

Genotoxicity in Artemia spp.: An old model with new sensitive endpoints

Artemia spp. represent models species widely used in ecotoxicological studies due to its simple and fast manipulation in laboratory conditions that makes this crustacean well adaptable to several methodological approaches. Although cysts hatching, swimming behavior, reproductive success and mortality are the main endpoints used for the determination of toxicity, the detection of slight alterations induced by certain substances found at low concentrations in the environment may require more sensitive biomarkers. For this reason, the identification of DNA or chromosomal damages has been proposed as an additional and appreciable endpoint for the ecotoxicological assessment of environmental chemicals. Concerning Artemia models, only few studies indicated that the exposure to organic and inorganic compounds (i.e. pesticides, nanoparticles, bacterial products or heavy metals) can reduce the survival and fitness through the onset of DNA breaks or the dysregulation of key genes. In contrast, literature research revealed a lot of works primarily focusing on the mortality and hatching rates of Artemia nauplii and cysts despite the well-known low sensitivity of these species. The present review reports the current state of knowledge concerning the effects induced by various chemicals, including organic and inorganic compounds, on the common parameters and genotoxicity in both Artemia franciscana and Artemia salina. Advantages and limitations of Artemia spp. models in eco-toxicological investigations together with the most used classes of compounds are briefly discussed. Moreover, a mention is also addressed to scarce availability of literature data focusing on genotoxic effects and the great reliability of molecular approaches observed in this poorly sensitive model organism. Thus, the opportunity to take advantage of genotoxic analyses has also been highlighted, by suggesting this approach as a novel endpoint to be used for the eco-toxicological assessment of several stressors.

Different cellular mechanisms from low- and high-dose zinc oxide nanoparticles-induced heart tube malformation during embryogenesis

With the wide application of nanometer materials in daily life, people pay more attention to the potential toxicity of nanoparticles to human fetal development once the nanoparticles are absorbed into the human body during pregnancy. However, there was no directly solid evidence for ZnO NPs-caused congenital heart defects. Hence, we investigated the effect of ZnO NPs exposure on early cardiogenesis using the chicken/mouse embryo models. First, we showed ZnO NPs reduced H9c2 cell viability in a dose- and time-dependent manner, while cell autophagy was significantly activated too on the same pattern. During early cardiogenesis, ZnO NPs exposure increased the chance of heart tube malformation, while precardiac cell apoptosis rises in the phenotype of closure defect and Bifida. The hypertrophy was also observed in late-stage chicken/mouse survival embryos exposed to ZnO NPs. Apart from cell apoptosis, high-dose ZnO NPs exposure led to massive programmed necrosis, and further experiments verified that ferroptosis remained primarily in ZnO NPs-induced programmed necrosis. We also revealed that the toxicology of low-dose ZnO NPs was mainly featured in the changes of expressions of key genes instead of causing precardiac cell death. MYL2 and CSRP3 could work as the downstream molecules of the above key genes in the context of ZnO NPs exposure to early cardiogenesis based on RNA sequencing. Taken together, this study for the first time revealed the potential risk of heart tube malformation induced by ZnO NPs exposure through different cellular mechanisms, which depended on low- or high-dose ZnO NPs.

Biochemical response of Ficopomatus enigmaticus adults after exposure to organic and inorganic UV filters

With the increase of UV filters usage and consequent release into aquatic environments, the concerns about their potential ecological risks are also increasing. According to this, in the present study, adult polychaetes of the species Ficopomatus enigmaticus were chronically exposed to three concentrations (0.01, 0.1 and 0.5 mg/L) of organic and inorganic filters (Ethylhexyl methoxycinnamate (EHMC) and nanoparticulate Zinc oxide (nZnO), respectively) in order to analyse biochemical responses related to cellular damage, antioxidant defence, biotransformation mechanisms and, lastly, neurotoxicity. Despite major lipid peroxidation caused by EHMC was observed, both UV filters have produced the same response patterns. In details, a clear concentration-dependent activation of glutathione S-transferases and a significant decrease of acetylcholinesterase levels defined an important neurotoxic effect was observed for both contaminants. These results become important to expand the limited scientific literature on biochemical responses of marine and brackish water invertebrates to organic and inorganic UV filters.

Interactive effects of ZnO nanoparticles and temperature on molecular and cellular stress responses of the blue mussel Mytilus edulis

Temperature is an important abiotic factor that modulates all aspects of ectotherm physiology, including sensitivity to pollutants. Nanoparticles are emerging pollutants in coastal environments, and their potential to cause toxicity in marine organisms is a cause for concern. Here we studied the interactive effects of temperature (including seasonal and experimental warming) on sublethal toxicity of ZnO nanoparticles (nano-ZnO) in a model marine bivalve, the blue mussel Mytilus edulis. Molecular markers were used to assess the pollutant-induced cellular stress responses in the gills and the digestive gland of mussels exposed for 21 days to 10 μg l^-1 and 100 μg l^-1 of nano-ZnO or dissolved Zn under different temperature regimes including ambient temperature (10 °C and 15 °C in winter and summer, respectively) or experimental warming (+5 °C). Exposure to high concentration (100 μg l^-1) of nano-ZnO caused oxidative injury to proteins and lipids and induced a marked apoptotic response indicated by increased transcript levels of apoptosis-related genes p53, caspase 3 and the MAPK pathway (JNK and p38) and decreased mRNA expression of anti-apoptotic Bcl-2. No significant induction of inflammatory cytokine-related response (TGF-β and NF-κB) of tissues was observed in nano-ZnO exposed-mussels. Furthermore, the oxidative injury and apoptotic response could differentiate the effects of nano-ZnO from those of dissolved Zn in the mussels. This study revealed that oxidative stress and stress-related transcriptional responses to nano-ZnO were strongly modified by warming and season in the mussels. No single biomarker could be shown to consistently respond to nano-ZnO in all experimental groups, which implies that multiple biomarkers are needed to assess nano-ZnO toxicity to marine organisms under the variable environmental conditions of coastal habitats.

Co-exposure of carbon nanotubes with carbofuran pesticide affects metabolic rate in Palaemon pandaliformis (shrimp)

Palaemon pandalirformis (shrimp) is a species widely distributed in the Brazilian coastal region and with an important economic role. In addition, this organism is considered an indicator of environmental pollution in estuaries; however, its physiological responses to toxic environmental pollutants, including pesticides and nanomaterials, are not well known, mainly, the effects of co-exposure. Thus, the purpose of this study was to evaluate the ecotoxicological effects of co-exposure between oxidized multiwalled carbon nanotubes (HNO₃-MWCNT) and carbofuran pesticide on the routine metabolism of P. pandalirformis. The shrimps were exposed to different concentrations of HNO₃-MWCNT (0; 10; 100; 500; 1000 μg L^-1), carbofuran (0; 0.1; 1.0; 5.0; 10 μg L^-1) and to co-exposure with 100 μg L^-1 of HNO₃-MWCNT + carbofuran (0; 0.1; 1.0; 5.0; 10 μg L^-1), to evaluate the effects on metabolic rate (O₂ consumption) and excretion of ammonia (NH₄+NH₃). Our results showed that the shrimps exposed to HNO₃-MWCNT (10 μg L^-1) increased the metabolic rate by 292% and the excretion of ammonia by 275%; those exposed to carbofuran (10 μg L^-1) increased their metabolic rate by 162% and the excretion of ammonia by 425%; and with the co-exposure of HNO₃-MWCNT + carbofuran there was also an increase in the metabolic rate by 317% and an excretion of ammonia by 433% when compared to control. These findings provides useful information toward better understanding the physiological responses of shrimps after combined exposure to nanomaterials and pesticides in aquatic environments.

Effects of dinoflagellate Gymnodinium catenatum on swimming behavior and expression of heat shock protein (hsp) genes in the brine shrimp Artemia franciscana

To understand the effects of the toxic marine dinoflagellate, Gymnodinium catenatum, on the brine shrimp, Artemia franciscana, we examined the acute toxicity and swimming behavior parameters such as swimming speed, swimming distance, and swimming path trajectory with transcriptional regulation of heat shock protein (hsp) genes in response to G. catenatum exposure. Mortality was not observed in response to G. catenatum. In the case of swimming behavior parameters, swimming speed and swimming distance were significantly decreased (P < 0.05) for 5 min at three concentrations (240, 360, and 600 cells/mL) of G. catenatum, whereas no significant change in swimming path trajectory was observed, suggesting that G. catenatum has potential adverse effects on the swimming behavior of A. franciscana. Additionally, the four A. franciscana-hsp genes (hsp26, hsp40, hsp70, and hsp90) were upregulated in response to G. catenatum. In particular, A. franciscana-hsp40 was significantly upregulated in response to 600 cells/mL G. catenatum, suggesting that A. franciscana-hsp genes are highly associated with cellular defense mechanisms and that A. franciscana-hsp40 is a potential biomarker for G. catenatum exposure. Overall, this study improves our understanding of the effects of G. catenatum on the swimming behavior and cellular defense mechanisms of A. franciscana.

Progress and prospects of applying carbon-based materials (and nanomaterials) to accelerate anaerobic bioprocesses for the removal of micropollutants

Carbon‐based materials (CBM), including activated carbon (AC), activated fibres (ACF), biochar (BC), nanotubes (CNT), carbon xenogels (CX) and graphene nanosheets (GNS), possess unique properties such as high surface area, sorption and catalytic characteristics, making them very versatile for many applications in environmental remediation. They are powerful redox mediators (RM) in anaerobic processes, accelerating the rates and extending the level of the reduction of pollutants and, consequently, affecting positively the global efficiency of their partial or total removal. The extraordinary conductive properties of CBM, and the possibility of tailoring their surface to address specific pollutants, make them promising as catalysts in the treatment of effluents containing diverse pollutants. CBM can be combined with magnetic nanoparticles (MNM) assembling catalytic and magnetic properties in a single composite (C@MNM), allowing their recovery and reuse after the treatment process. Furthermore, these composites have demonstrated extraordinary catalytic properties. Evaluation of the toxicological and environmental impact of direct and indirect exposure to nanomaterials is an important issue that must be considered when nanomaterials are applied. Though the chemical composition, size and physical characteristics may contribute to toxicological effects, the potential toxic impact of using CBM is not completely clear and is not always assessed. This review gives an overview of the current research on the application of CBM and C@MNM in bioremediation and on the possible environmental impact and toxicity.

Inulin-Coated Iron Oxide Nanoparticles: A Theranostic Platform for Contrast-Enhanced MR Imaging of Acute Hepatic Failure

The present study introduces a superparamagnetic nanocomposite, Fe-Si-In, as a T2 magnetic resonance imaging (MRI) contrast agent with a core of iron oxide nanoparticles and a nonporous silica inner shell/carboxymethyl inulin outer shell. Due to its core/shell properties, the structure characterization, biocompatibility, and performance in MRI, as well as its potential as a drug delivery system, were thoroughly evaluated. The results have shown that the synthesized nanocomposite possesses excellent biocompatibility and acceptable magnetization (M_s = 20 emu g^-1). It also has the potential to be a nanocarrier for drug delivery purposes, as evidenced by the results of curcumin administration studies. The developed nanocomposite has shown excellent performance in MRI, while the in vitro relaxivity measurements reveal a stronger T2 relaxivity (r₂ = 223.2 ms) compared to the commercial samples available in the market. Furthermore, the in vivo MRI studies demonstrate an excellent contrast between injured livers and normal ones in rats which again upholds the high performance of Fe-Si-In in MRI diagnostics.

Short exposure of Artemia salina to group-12 metals: Comparing hatchability, mortality, lipid peroxidation, and swimming speed

The hatchability, mortality rate, lipid peroxide levels, and swimming speed of Artemia salina have been compared based on short exposures of ZnCl₂, CdCl₂, and HgCl₂ in artificial seawater. The hatching tests were carried out for 12, 24, 36, and 48 h at 28 °C. Mortality rate and lipid peroxide (LPO) levels were determined after 24 h of exposure at 28 °C, in the dark, and on living larvae using the FOX method. The swimming speed was determined after 24 h using a microcomputer coupled to a digital camera, with simultaneous treatment of the recorded images every 25 s, at 25 °C, under red-light irradiation. Results showed that Zn caused a gradual inhibition of the hatching for concentrations <900 µmol L^-1; however, Cd and Hg displayed almost complete inhibition for concentrations ≤100 µmol L^-1. Also, the heavy metals caused a dose-dependent increase of mortality (LD50) in the following order: Zn = 3290 µmol L^-1 < Cd = 2206 µmol L^-1 < Hg = 15.6 µmol L^-1. Furthermore, significant LPO levels were found for Cd (1500-2000 µmol L^-1, p < 0.001) and Hg (5-20 µmol L^-1, p < 0.001). Finally, the swimming speed values increased significantly, for Zn ≈ 2.5 mm s^-1 (1500 µmol L^-1, p < 0.001), Cd ≈ 3.5 mm s^-1 (2000 µmol L^-1, p < 0.05), and Hg ≈ 4.0 mm s^-1 (15 µmol L^-1, p < 0.05), after 24 h exposure. There is a clear dose-dependent toxicity, indicating that Zn, Cd and Hg can induce significant changes in hatchability, mortality, and ethological and biochemical parameters.

Green Synthesis of Nickel Oxide Nanoparticles from Berberis balochistanica Stem for Investigating Bioactivities

Green synthesis of nanomaterials is advancing due to its ease of synthesis, inexpensiveness, nontoxicity and renewability. In the present study, an eco-friendly biogenic method was developed for the green synthesis of nickel oxide nanoparticles (NiONPs) using phytochemically rich Berberis balochistanica stem (BBS) extract. The BBS extract was rich in phenolics, flavonoids and berberine. These phytochemicals successfully reduced and stabilised the NiNO₃ (green) into NiONPs (greenish-gray). BBS-NiONPs were confirmed by using UV-visible spectroscopy (peak at 305 nm), X-ray diffraction (size of 31.44 nm), Fourier transform infrared spectroscopy (identified -OH group and Ni-O formation), energy dispersive spectroscopy (showed specified elemental nature) and scanning electron microscopy (showed rhombohedral agglomerated shape). BBS-NiONPs were exposed to multiple in vitro bioactivities to ascertain their beneficial biological applications. They exhibited strong antioxidant activities: total antioxidant capacity (64.77%) and 2, 2-diphenyl-1-picrylhydrazyl (71.48%); and cytotoxic potential: Brine shrimp cytotoxicity assay with IC₅₀ (10.40 µg/mL). BBS-NiONPs restricted the bacterial and fungal pathogenic growths at 1000, 500 and 100 µg/mL. Additionally, BBS-NiONPs showed stimulatory efficacy by enhancing seed germination rate and seedling growth at 31.25 and 62.5 µg/mL. In aggregate, BBS extract has a potent antioxidant activity which makes the green biosynthesis of NiONPs easy, economical and safe. The biochemical potential of BBS-NiONPs can be useful in various biomedical and agricultural fields.

Acute toxicity assessment of polyaniline/Ag nanoparticles/graphene oxide quantum dots on Cypridopsis vidua and Artemia salina

Nanotoxicology is argued and considered one of the emerging topics. In this study, polyaniline (PANI)/2-acrylamido-2-methylpropanesulfonic acid (AMPSA) capped silver nanoparticles (NPs)/graphene oxide (GO) quantum dots (QDs) nanocomposite (PANI/Ag (AMPSA)/GO QDs NC) as a nanoadsorbent has a potential for removal of toxic hexavalent chromium (Cr(VI)) ions from water. The acute toxicity of this NC was evaluated on Artemia salina and freshwater Ostracods (Cypridopsis vidua) larvae for 48 h. The measurements were made at 24 and 48 h with 3 repetitions. The 50% effective concentration (EC50) values of the NC were determined after the exposure of these organisms. According to the results of the optical microscope, it was found that both experimental organisms intake the NC. In the toxicity results of Ostracods, the NC had a highly toxic effect only at 250 mg/L after 48 h and the EC50 value was 157.6 ± 6.4 mg/L. For Artemia salina individuals, it was noted that they were less sensitive than the Ostracods and EC50 value was 476 ± 25.1 mg/L after 48 h. These results indicated that PANI/Ag (AMPSA)/GO QDs NC has low toxicity towards both investigated organisms.

Evaluation of Toxicity with Brine Shrimp Assay

The in vivo toxicity of new metallodrugs either as Small Bioactive Molecules (SBAMs) or Conjugates of Metals with Drugs (CoMeDs) or their hydrogels such as with hydroxyethyl-methacrylate (HEMA) (pHEMA@SBAMs or pHEMA@CoMeDs) are evaluated by the brine shrimp assay. Thus individuals of Artemia salina larvae are incubated in saline solutions with SBAMs, CoMeDs, pHEMA@SBAMs or pHEMA@CoMeDs or without for 24 h. The toxicity is then determined in terms of the mortality rate of brine shrimp larvae. Brine shrimp assay is a low cost, safe, no required feeding during the assay, while it requiring only a small amount of the tested agent.

Toxicological evaluation of biosynthesised hematite nanoparticles in vivo

In recent years, nanomaterials have been widely used in consumer products. High reactivity of metallic nanoparticles and its bioaccumulation in biological systems are the main causes of concern over their safety to human health and environment. The available information related to the safety of several nanomaterials is insufficient. Hematite nanoparticles are proposed for various applications. Ecotoxicological studies of hematite nanoparticles are very limited. In the present study, biosynthesised hematite nanoparticles using Bacillus cereus were evaluated for its acute oral toxicity in mice following OECD guidelines. A dose of 2 g/kg/p.o was administered to Swiss albino mice through gastric oral feeding tube and observed for 14 days. After two weeks blood samples were collected and subjected for evaluation of haematological parameters and biochemical analysis. There was no mortality and toxic signs of animals till the end of observational period. The animals were sacrificed and organs like liver and kidneys were isolated to study the histopathological changes. The results of the study revealed that there was no drastic change in parameters except slight change in bilirubin in the hematite nanoparticle treated mice. Biosynthesised hematite nanoparticles were assayed for toxicity in Artemia salina. Cysts treated with higher concentrations of hematite nanoparticles showed small sized nauplii. Biosynthesised hematite nanoparticles were found to be non-toxic to A. salina nauplii in lower concentrations.

Active packaging for Salmon stored at refrigerator with Polypropylene nanocomposites containing 4A zeolite, ZnO nanoparticles, and green tea extract

In this study, three types of Polypropylene-based (PP) films (two active nanocomposites and one control film) containing zinc oxide nanoparticles (ZnO NPs), 4A zeolite (4A Z), and green tea extract (GTE) were studied as modern active packaging's that can adjust the release of antimicrobial agents. The influence of PP nanocomposite with 3% (w/w) ZnO NPs/4A Z/GTE (treatment 1) and 6% (w/w) ZnO NPs/4A Z/GTE (treatment 2) on controlling microbial growth and preserving the sensory and chemical qualities of Salmon over nine days of storage at 4 ± 1°C was evaluated. The disk diffusion test revealed inhibition zones in the range of 10.98 ± 0.03 to 13.42 ± 0.01 m for treatments 1 and 2, respectively; the nanocomposite film with 6% ZnO NPs/4A Z/GTE had the highest antimicrobial effect against Gram-negative bacteria (p < .05). Chemical analysis revealed that the initial peroxide value of Salmon was 0.68 ± 0.0 mEq/kg, which increased by day 9 to 12.3 ± 0.03 mEq/kg in the control sample, but rising only to 9.9 ± 0.01 and 7.3 ± 0.02 mEq/kg in treatments 1 and 2, respectively (p < .05). The shelf life of Salmon given treatment 2 increased significantly to nine days relative to the control. Accordingly, these nanocomposite films are promising as new active packaging for preventing microbial growth and preserving the quality of salmon.

Artemia salina: A microcrustacean to assess engineered nanoparticles toxicity

The focus of this work was to investigate the toxicity of different metal nanoparticles (gold nanoparticles [AuNPs], silver nanoparticles [AgNPs], titanium dioxide nanoparticles [TiO₂ NPs]) on brine shrimp Artemia salina. We investigated if nanoparticles could have an influence on hatching of cysts and on mortality of larvae. Larvae (also called nauplii) and cysts were exposed to NPs for 24 hr in artificial seawater on microplates. At the end of the test, we assessed the endpoint (immobility/death) for the larvae by a stereomicroscope. Nauplii that appeared completely motionless, were counted as dead, and the percentages of mortality were calculated for each treatment. Instead for the cysts, the percentages of not-hatched nauplii for each concentration considered were calculated by counting the number of whole cysts. Currently, nanoparticles toxicity has been investigated in several research; in our study we highlighted the nontoxicity of TiO₂ NPs on A. salina nauplii as shown by low percentages of immobilization and on cysts because TiO₂ NPs do not affect their hatching. Despite AuNPs exerted toxic effects on hatching, they did not affect larvae development as well as TiO₂ NPs. Otherwise, AgNPs induced mortality of the larvae and inhibited cysts hatching.

Chronic sublethal effects of ZnO nanoparticles on Tigriopus fulvus (Copepoda, Harpacticoida)

This study investigated for the first time the effects of ZnO nanoparticle (NP) chronic exposure (28 days) on Tigriopus fulvus. Acute toxicity (48 h) of three Zn chemical forms was assessed as well including the following: (a) ZnO nanoparticles (NPs), (b) Zn2+ from ZnO NP suspension after centrifugation (supernatant) and (c) ZnSO4 H2O. Physical-chemical and electronic microscopies were used to characterize spiked exposure media. Results showed that the dissolution of ZnO NPs was significant, with a complete dissolution at lowest test concentrations, but nano- and micro-aggregates were always present. Acute test evidenced a significant higher toxicity of Zn2+ and ZnSO4 compared to ZnO NPs. The chronic exposure to ZnO NPs caused negative effects on the reproductive traits, i.e. brood duration, brood size and brood number at much lower concentrations (≥ 100 μg/L). The appearance of ovigerous females was delayed at higher concentrations of ZnO NPs, while the time required for offspring release and the percentage of non-viable eggs per female were significantly increased. ZnO NP subchronic exposure evidenced its ability to reduce T. fulvus individual reproductive fitness, suggesting that ZnO NPs use and release must be carefully monitored. Graphical abstract Graphical Abstract.

Toxicity of Different Zinc Oxide Nanomaterials at 3 Trophic Levels: Implications for Development of Low-Toxicity Antifouling Agents

Because zinc oxide (ZnO) nanomaterials are used in antifouling and antibacterial solutions, understanding their toxic effects on different aquatic organisms is essential. In the present study, we evaluated the toxicity of ZnO nanoparticles of 10 to 30 nm (ZnONPI) and 80 to 200 nm (ZnONPII), ZnO nanorods (width 80 nm, height 1.7 µm) attached to the support substrate (glass, ZnONRG) and not attached (ZnONRS), as well as Zn²⁺ ions at concentrations ranging from 0.5 to 100 mg/L. Toxicity was evaluated using the microalga Dunaliella salina, the brine shrimp Artemia salina, and the marine bacterium Bacillus cereus. The highest toxicity was observed for ZnONPs (median lethal concentration [LC50] ~15 mg/L) and Zn²⁺ ions (LC50 ~13 mg/L), whereas the lowest toxicity found for ZnO nanorods (ZnONRG LC50 ~60 mg/L; ZnONRS LC50 ~42 mg/L). The presence of the support substrate in case of ZnO nanorods reduced the associated toxicity to aquatic organisms. Smaller ZnONPs resulted in the highest Zn²⁺ ion dissolution among tested nanostructures. Different aquatic organisms responded differently to ZnO nanomaterials, with D. salina and B. cereus being more sensitive than A. salina. Toxicity of nanostructures increased with an increase of the dose and the time of exposure. Supported ZnO nanorods can be used as a low-toxicity alternative for future antimicrobial and antifouling applications. Environ Toxicol Chem 2020;39:1343-1354. © 2020 SETAC.

Comparative effects of Cu (60-80 nm) and CuO (40 nm) nanoparticles in Artemia salina: Accumulation, elimination and oxidative stress

In this study, nanotoxicity tests were made by exposure of Artemia salina to copper (Cu 60-80 nm) and copper oxide (CuO 40 nm) nanoparticles (NPs) at different concentrations (0.2, 1, 5, 10, 25, and 50 mg/l) during some exposure duration. Characterization of Cu and CuO NPs were performed using Transmission Electron Microscope (TEM), Dynamic Light Scattering (DLS), Zeta Potential, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transformation Infrared (FT-IR) analyzes. In organisms, the accumulation and elimination rates of NPs was determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) analysis and the oxidative stress effects on A. salina were determined by Glutathione (GSH) and Thiobarbituric acid reactive substances (TBARS) analysis methods. Both NPs were found to differ in accumulation and elimination rates at each application time and in parallel with the increase in concentration. In each group, it was determined that ion release increased with application time. The results showed that the accumulation rates in Cu NPs had a tendency to increase at 48 h and to decrease at 72 h in concentrations of 0, 2 and 1 mg/l, respectively. And in the all other concentrations have been seen an increasing trend within the time. In the CuO NPs (40 nm), accumulation rates were a decrease trend at 48th hour and an increase trend at 72nd hour except 10 mg/l concentration. In the 10 mg/l group was an increase trend with the application period. Cu NP, TBARS value increased with increasing concentrations and the highest increase was observed at 24 h of 5 ppm group. The groups showed a tendency to increase-decrease-increase-decrease in TBARS levels in terms of elapsed time (24th, 48th, 72nd hour and elimination) (5 ppm and 10 ppm groups tended to decrease in TBARS level at 72nd hour). TBARS increased with increasing concentration ratios in CuO NPs (40 nm).

Effects of Zn and ZnO Nanoparticles on Artemia salina and Daphnia magna Organisms: Toxicity, Accumulation and Elimination

In the study, Zn in the size of 40-60 nm and 80-100 nm and ZnO in the size of 10-30 nm were applied to A. salina and D. magna individuals in 7 groups with 3 repetitions. Measurements were made at 24^th, 48^th and 72^nd hours and elimination values were examined at +24 h. LC₅₀ values of NPs were determined and chemical analysis (metal accumulation and elimination), ion quantities which were given to the environment and the survival rates of organisms were determined after the exposure. According to the results of phase contrast microscopy, it was found that both experimental organisms absorbed the NPs in the medium level. In the toxicity results of D. magna, it can be said that Zn NP (40-60 nm) has a highly toxic effect only at 50 ppm concentration for 48 h and lethal dose can be accepted as of 5 ppm at the end of 72 h. In A. salina individuals, it is clearly seen that there is an increase in mortality in organisms parallel to the dose increase. Although all NPs were applied to organisms in low doses corresponding to environmental values, it was observed that toxic effect was in parallel with the increase in time. It is clearly known that there is the inverse proportion between the size of NPs and the toxic effect. The smaller the size of NPs is, the higher the toxic effect becomes When the results of Zn accumulation and elimination of A. salina and D. magna individuals exposed to the Zn and ZnO NPs were examined; it was found that accumulation and elimination occurred in parallel with the increase in concentration at each application hour and elimination. Intensive and possible misuse of nanoscale materials is one of the biggest threats to the environment and all living things worldwide.

Biocompatibility assessment of Fe3O4 nanoparticles using Saccharomyces cerevisiae as a model organism

Using Saccharomyces cerevisiae as an experimental model, the potential toxicological effects of Fe₃O₄ nanoparticles (Fe₃O₄-NPs) were investigated following exposure to 0-600 mg/L for 24 h. Results revealed that cell proliferation was significantly inhibited by Fe₃O₄-NPs with an IC₅₀ value of 326.66 mg/L. Mortality showed a concentration-dependent increase, and the highest concentration in this study (600 mg/L) resulted in 22.30% mortality. In addition, Effects on proliferation and mortality were accounted for Fe₃O₄-NPs rather than iron ion released from Fe₃O₄-NPs. Scanning and transmission electron microscope observation showed that Fe₃O₄-NPs extensively attached on the cell surfaces, causing cells to deform and shrink. Moreover, Fe₃O₄-NPs could be internalized in S. cerevisiae cells via endocytosis and then be distributed in cytoplasm and vesicles. The data of uptake kinetics demonstrated that the maximal accumulation (4.898 mg/g) was reached at 15 h. Besides, percentage of late apoptosis/necrosis was observably increased (p < 0.01) at 600 mg/L (15.80%), and the expression levels of apoptosis-related genes (SOD, Yca1 and Nuc1) were dramatically increased following exposure to Fe₃O₄-NPs for 24 h. As expected, mitochondrial transmembrane potential was significantly decreased (p < 0.01) at 50-600 mg/L, and biomarkers of oxidative stress (ROS, CAT and SOD) were also markedly changed following exposure. Altogether, the combined results so far indicated Fe₃O₄-NPs could induce S. cerevisiae cell apoptosis that mediated by mitochondrial impairment and oxidative stress.

The effects of ZnO nanostructures of different morphology on bioenergetics and stress response biomarkers of the blue mussels Mytilus edulis

Biofouling causes massive economical losses in the maritime sector creating an urgent need for effective and ecologically non-harmful antifouling materials. Zinc oxide (ZnO) nanorod coatings show promise as an antifouling material; however, the toxicity of ZnO nanorods to marine organisms is not known. We compared the toxicity of suspended ZnO nanorods (NR) with that of ZnO nanoparticles (NP) and ionic Zn²⁺ in a marine bivalve Mytilus edulis exposed for two weeks to 10 or 100 μg Zn L^-1 of ZnO NPs, NRs or Zn²⁺, or to immobilized NRs. The multi-biomarker assessment included bioenergetics markers (tissue energy reserves, activity of mitochondrial electron transport system and autophagic enzymes), expression of apoptotic and inflammatory genes, and general stress biomarkers (oxidative lesions, lysosomal membrane stability and metallothionein expression). Exposure to ZnO NPs, NRs and Zn²⁺ caused accumulation of oxidative lesions in proteins and lipids, stimulated autophagy, and led to lysosomal membrane destabilization indicating toxicity. However, these responses were not specific for the form of Zn (NPs, NR or Zn²⁺) and showed no monotonous increase with increasing Zn concentrations in the experimental exposures. No major disturbance of the energy status was found in the mussels exposed to ZnO NPs, NRs, or Zn²⁺. Exposure to ZnO NPs and NRs led to a strong induction of apoptosis- and inflammation-related genes, which was not seen in Zn²⁺ exposures. Based on the integrated biomarker response, the overall toxicity as well as the pro-apoptotic and pro-inflammatory action was stronger in ZnO NPs compared with the NRs. Given the stability of ZnO NR coatings and the relatively low toxicity of suspended ZnO NR, ZnO NR coating might be considered a promising low-toxicity material for antifouling paints.

Stability of nickel oxide nanoparticles and its influence on toxicity to marine algae Chlorella vulgaris

This study considered the stability of nickel oxide nanoparticles (nNiO) in seawater including their ability of aggregation and ion release. Furthermore, the relationship between these properties and their toxicity on marine algae Chlorella vulgaris was investigated. The results showed nNiO inhibited the growth of algal cells and decreased their chlorophyll content, which was due to the shading effects by aggregation of nNiO in seawater. Moreover, the release of Ni²⁺ depended on concentration of the nNiO solution. About 1.63% Ni²⁺ (varied from 0.89 to 3.63%) was detected and it may mediate the generation of ROS under both visible light and ultraviolet (UV) irradiation, which resulted in oxidative stress in algae. Therefore, the stability of nNiO in water affected its toxicity, which should be considered when assessing the nano-pollution risks in aquatic ecosystem.

Uptake and effects of different concentrations of spherical polymer microparticles on Artemia franciscana

Artemia cysts have a huge economic importance for the aquaculture sector due to the fact that they are used as live feed for larviculture. Microplastics (MPs) are common and emergent pollutants in the aquatic environments, with unknown and potential long-term effects on planktonic species such as Artemia spp. When used as live feed, Artemia could transfer contaminants to fish along the food chain, with possible adverse effects on human health through their consumption. This study aims to assess the uptake of different concentrations of spherical polymer microparticles (FRM) (1-5 μm diameter) and their associated chronic effects on feeding, growth, mortality, and reproductive success from juvenile to adult stage of brine shrimp Artemia franciscana. Individuals were exposed for 44 days to 0.4, 0.8 and 1.6 mg.L^-1 of FRM. No significant detrimental effects on growth, ingestion and mortality rates of A. franciscana were observed in all tested conditions. However, reproductive success was strongly affected by the increase of MP concentrations. The results of the present study showed that A. franciscana juveniles and adults were able to survive different experimental MP concentrations, but their reproductive success and progeny were significantly impacted by exposure to FRM particles.

Trophic transfer of CuO nanoparticles from brine shrimp (Artemia salina) nauplii to convict cichlid (Amatitlania nigrofasciata) larvae: uptake, accumulation and elimination

We investigated the trophic transfer potential of CuO-NPs from Artemia salina to Amatitlania nigrofasciata. The Cu uptake was investigated by exposure of the instar II nauplii to 0, 1, 10, and 100 mg/L CuO-NPs for 4 h. Dietborne exposure of fish larvae to CuO-NPs was done for 21 days through feeding with pre-exposed nauplii. Thereafter, all survived fish were fed for 21 more days with non-contaminated nauplii. The results showed that NPs could be taken up by nauplii in a concentration-dependent manner. The highest uptake of Cu by nauplii was found to be 50.5 ± 1.4 mg/g dry weight at 100 mg/L. The copper accumulation in fish larvae increased significantly with increasing Cu content in pre-exposed nauplii to different concentrations of CuO-NPs (p < 0.05). At the end of the depuration phase, although the Cu elimination was significantly higher in fish that were fed with more contaminated nauplii, but the survival rate, average final weight, and length of those larvae was still significantly less than the control group (p < 0.05). The accumulated Cu after the depuration phase in cichlid larvae was 25.4 ± 0.5, 29 ± 8.0, 33.9 ± 9.7, and 42.3 ± 4.0 μg/g dry weight at 0, 1, 10, and 100 mg/L of CuO-NPs-treated Artemia. The current findings indicated the ability of manufactured CuO-NPs to be transferred from one trophic level to the next as assessed in the simple food chain consisting of pre-exposed A. salina and A. nigrofasciata.

DNA damages and offspring quality in sea urchin Paracentrotus lividus sperms exposed to ZnO nanoparticles

The recent advances in nanotechnology lead to a potential increase of the release of nanoparticles (NPs) into marine environment through different routes, with possible toxic effects upon the living part of this ecosystem. One of the ways of NPs marine contamination gaining today increasing concern stems from the widespread use cosmetics containing ZnO NPs as UV-filter. Although the possible adverse effects on marine organisms have been already ascertained, the information about the possible genotoxicity of ZnO NPs is still scant. In this work the spermiotoxicity of ZnO particles of different sizes (ZnO Bulk > 200 nm, ZnO NPs 100 nm and ZnO NPs 14 nm) was assessed, using Paracentrotus lividus spermatozoa, by evaluating the DNA damage of the exposed sperm, fertilization capability and DNA damage transmission to progeny. Our results showed that ZnO NPs induced DNA damages in spermatozoa after 30 min of exposure. While the sperm fertilization capability was not affected, morphological alterations (skeletal alterations) in offspring were observed and a positive correlation between sperm DNA damage and offspring quality was reported. This study underlines that a possible spermiotoxic action of ZnO NPs at concentration close to those reported in marine coastal water could occur.

Phyco-linked vs chemogenic magnetite nanoparticles: Route selectivity in nano-synthesis, antibacterial and acute zooplanktonic responses

Despite the fact that magnetic iron oxide nanoparticles (Fe₃O₄-MNPs) considered as the most promising nanoparticles (NPs) in biomedicine and environmental biotechnology, their safety and ecotoxicological impacts of biogenic and chemogenic routes of Fe₃O₄-MNPs in the marine aquatic system is scarcely studied. In this work, we report the optimized and suitable phyco-synthesis route for nano-Fe₃O₄ based on the six selected species of the Persian Gulf seaweeds: Ulva prolifera, U. flexuosa, U. linza, U. intestinalis, U. clathrata, and Sargassum boveanum. Moreover, antibacterial activities and acute zooplanktonic responses in Artemia salina and acorn barnacle Amphibalanus amphitrite to chemogenic and biogenic Fe₃O₄-MNPs, were evaluated. Although all the seaweeds extract showed reducing potential for Fe₃O₄-MNPs green synthesis - mainly on the basis of characterization results- the algal route selectivity has been demonstrated to be important for the biosynthesis of magnetite NPs. Herein, the cubo-spherical and polydisperse U. prolifera-derived Fe₃O₄-MNPs with particles sizes of 9.59 nm were the best ones. The comparative zooplanktonic cytotoxicity of chemo- and bio-route of Fe₃O₄-MNPs exhibited no acute toxicity in nauplii and adults of A. salina (96-h EC₅₀ ≥ 1000 mg/L) and the potential of toxicity in A. amphitrite nauplii (48-h EC₅₀ = 466.5 and 842.3 mg/L for chemo- and bio-route of Fe₃O₄-MNPs, respectively). The in vitro antimicrobial activity of both chemo- and bio-route of magnetite NPs to selective human pathogenic bacteria and fungi (i.e. n = 11) showed strong antagonistic activity against Staphylococcus epidermidis, Bacillus subtilis, B. pumulis, and Saccharomyces cerevisiae. In conclusion, these findings demonstrate the optimized phyco-fabrication of Fe₃O₄-MNPs as promising nontoxic approach in ecobiotechnology, the new insight about the potential adverse effects of chemosynthesized Fe₃O₄-MNPs to crustacean zoo-organisms after their possible entrance into the marine environments, and bio/chemo-route Fe₃O₄-MNPs as pivotal agent for nanoantimicrobials.

Toxicity of TiO2, SiO2, ZnO, CuO, Au and Ag engineered nanoparticles on hatching and early nauplii of Artemia sp

The potential of environmental release enhances with increased commercial applications of the nanomaterials. In this work, a simple and efficient test to estimate the acute toxicity of nanoparticles is carried out on Artemia species and their hatching rates. We have tested six different engineered nanoparticles (silver, gold, copper oxide, zinc oxide, TiO₂ and SiO₂ nanoparticles) and three soluble salts (CuSO₄, ZnSO₄ and AgNO₃) on Artemia sp. The physicochemical properties of the nanoparticles involved in this study were analyzed in normal water and marine water. Hydrated and bleached Artemia cysts were allowed to hatch in continuously aerated, filtered sterile salt water containing nanoparticles; hatching of viable nauplii and total hatchlings have been recorded. In parallel, standard Artemia toxicity test was conducted on the nauplii monitoring the viability. In hatching experiments, a reduction in hatching rate was observed along with mortality of newly hatched nauplii. The results of the hatching experiment and of the standard Artemia test showed a good correlation. The toxicity of the nanoparticles was compared and the order of toxicity was estimated as Ag>CuO>ZnO>Au>TiO₂>SiO₂. The study thus suggests that the hatching test itself is a reliable assay for determining the toxicity of nanomaterials.

Distinctive impact of polystyrene nano-spherules as an emergent pollutant toward the environment

The increasing load of nanoplastic pollution in the environment has become a major concern toward human and environmental safety. The current investigation mainly focused on assessing the toxic behavior of nanoplastics (polystyrene nano-spheres (PNS)) toward blood cells and marine crustacean. The study also investigated the temporal stability of PNS under different water matrices and its size-dependent sedimentation behavior in the sea water dispersion. The nano-dispersion showed mean particle size of 561.4 ± 0.80 and 613.7 ± 0.11 nm for PNS 1 and 781.4 ± 0.80 and 913.7 ± 0.11 nm for PNS 2 in lake and seawater, respectively after 48-h incubation, which is ~ 8-fold increase from its original size. The LC50 value against Artemia salina and lymphocytes were found to be 4.82 and 8.79 μg/mL, and 75 μg/mL, respectively for PNS 1 and PNS 2. The genotoxic study reveals that around 50% of lymphocytes were affected by both PNS at 50 μg/mL concentration, whereas the cytotoxic studies on RBC and lymphocytes showed 50% toxicity only at 100 μg/mL concentration. The genotoxic study displayed numerous tri- and multi-nucleated cells. The biochemical profile of A. salina exposed to lethal concentration demonstrated a significant decrease in the total protein, reduced glutathione, and catalase activity and increase in lipid peroxidation activity as a result of PNS permeation to tissues. In conclusion, the present study demonstrated that the polystyrene nano-spheres are emerging pollutant in the environment and are hazardous to humans.

Toxicity assessment and histopathological analysis of nano-ZnO against marine fish (Mugilogobius chulae) embryos

The toxicity of nano-materials has received increasing attention in recent years. Nevertheless, relatively few studies have focused on their oceanic distributions and toxicities. In this study, we assessed nano-ZnO toxicity in marine organisms using the yellowstriped goby (Mugilogobius chulae). The relative differences in nano-ZnO dissolution and dispersal in seawater and fresh water were also investigated. The effects of nano-ZnO on embryonic development, deformity, hatching, mortality, and histopathology were analyzed. In addition, the effects of the Zn²⁺ concentration on M. chulae hatching and mortality were compared. The results showed that nano-ZnO had higher solubility in seawater than in fresh water. Nano-ZnO significantly inhibited hatching. By the fifth day of exposure, the LC₅₀ of nano-ZnO was 45.40mg/L, and the mortality rate spiked. Hatching inhibition and lethality were dose-dependent over a range of 1-25mg/L nano-ZnO. Zn²⁺ inhibited hatching and increased lethality, but its effects were weaker than those of nano-ZnO at the same concentrations. Nano-ZnO also induced spinal bending, oedema, hypoplasia, and other deformities in M. chulae embryos and larvae. Histopathology revealed vacuolar degeneration, hepatocyte and enterocyte enlargement, and morphological abnormalities of the vertebrae. Therefore, nano-ZnO caused malformations in M. chulae by affecting embryonic growth and development. We conclude that nano-ZnO toxicity in seawater was significantly positively correlated with the associated Zn²⁺ concentration and sedimentary behaviour. The toxicity of nano-ZnO was cumulative and showed a critical point, beyond which embryonic and developmental toxicity in marine fish was observed.

A novel strategy for water disinfection with a AgNPs/gelatin sponge filter

Disinfection of bacteria in water with sustainable and energy-efficient methods is still a great challenge. Herein, a novel gelatin sponge with embedded AgNPs is fabricated via freeze-drying using gelatin as the reducing agent to synthesize AgNPs in situ. UV-vis spectroscopy, HRTEM, XRD, and XPS characterization prove the formation of AgNPs with an average size of 8.55 ± 0.35 nm. TEM and SEM images confirm the even distribution of AgNPs throughout the AgNPs/gelatin sponges. The composite sponge has a low bulk density of 20 ± 3.5 mg/cm³ and a pore size of 6.2 ± 1.5 μm. The AgNPs/gelatin sponges exhibit excellent antibacterial performance to E. coli in water, probably by destroying their cell membranes. The porous AgNPs/gelatin composite sponges are promising filter materials for water disinfection. The removal rate of AgNPs/gelatin composite sponges on E. coli reached almost 100%. Graphical abstract ᅟ.

Organic and inorganic nano-Fe3O4: Alga Ulva flexuosa-based synthesis, antimicrobial effects and acute toxicity to briny water rotifer Brachionus rotundiformis

Following the recent progress in magnetic nanotechnology, concern over the optimal benefits and potential risks of iron oxide nanoparticles (Fe NPs), has increased. Hence, to minimize the negative impacts of inorganic Fe NPs, we report the phyco-synthesis and characterization of superparamagnetic Fe₃O₄ NPs via reduction of ferric/ferrous chloride solution (2:1 M ratio; 88 °C) with green macroalga, Ulva flexuosa (wulfen) J.Agardh aqueous extract. The biogenic process is clean, eco-friendly, rapid, and facile to handle. These green fabricated magnetite NPs are characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), particle size analysers (PSA), zeta potential (ZP) measurement, and vibrating sample magnetometry (VSM) techniques. The results confirmed that the cubo-spherical, polydisperse of biosynthesized Fe₃O₄ NPs with an average diameter of 12.3 nm was formed. The antagonistic effects of algal extract, chemo-route and U. flexuosa-derived Fe₃O₄ MgNPs on selective human pathogenic microbes (i.e. n = 11) resulted in strong antibacterial and moderate antifungal activity. The comparative toxic and reproductive effects of the chemo- and bio-routes of Fe₃O₄-MgNPs against rotifer B. rotundiformis exhibited low acute toxicity with a lower inducing effect of biogenic nano-magnetite on reduction rotifer reproductive rate than its chemogenic counterpart. In view of the nanoecotoxicity, though the current study covered a wide range of exposure concentrations (10-500 mg/L) of organic and inorganic nano sizes of Fe₃O₄ in brackish water rotifer, a biotoxicity assay at higher dosage or a comprehensive risk assessment in different aqua-organisms is recommended.