Toxicity Of AgNPs Research Articles

Differential tolerance of Trichoderma harzianum and Rhizoctonia solani towards silver nanoparticles: potential for agricultural applications?

In the previous study, we examined the effect of silver nanoparticles (AgNPs) on beneficial soil fungus including Trichoderma harzianum (T22), and pathogenic soil-borne fungus, Rhizoctonia solani (AG3-PT). The result exhibited that T. harzianum (T22) is tolerance towards AgNPs. On the other hand, the pathogenic fungi, R.solani (AG3-PT), is more sensitive to AgNPs. T. harzianum is well known as biocontrol agent to suppress R. solani. Therefore, in this study we investigated the combination of T. harzianum (T22) and AgNPs at low concentration to control two strains of R. solani (AG3-PT and AG2-1). The effect of AgNPs at two different levels (20 mg L-1 and 50 mg L-1) was examined over the growth of the two strains of R. solani and T. harzianum (T22) using dual culture technique. The results shows that this combination have a potential to reduce colony growth of R. solani (AG2-1) at higher AgNPs concentration. However, it was not the case for R. solani (AG3-PT). It can be concluded that AgNPs toxicity depend on several factors including species strain and the size of AgNPs particle.

Trophic transfer and toxicity of silver nanoparticles along a phytoplankton-zooplankton-fish food chain

This study evaluated the bioconcentration metrics, organ-specific distribution, and trophic consequences of silver nanoparticles along a Dunaliella salina-Artemia salina-Poecilia reticulata food chain. To this end, accumulation, tissue-specific distribution, bioconcentration and biomagnification factors, and trophic toxicity of AgNPs were quantitatively investigated along di- and tri-trophic food chains. Overall, silver accumulation increased markedly in intestine and liver tissues, carcass, and embryos of guppy fish with rising exposure concentrations and reducing trophic levels. Following trophic and waterborne exposure, AgNPs illustrated a regular tendency in following order: intestine > liver > embryos > carcass. BCF displayed values of 826, 131, and ≈ 1000 for microalgae, brine shrimp, and guppy fish, respectively. Moreover, BMF showed values <1.00 for 48-h post-hatched nauplii and guppy fish received AgNPs-exposed phytoplankton, yet >1.00 for the liver and whole body of guppy fish treated with AgNPs-exposed nauplii through algae and water, indicating that AgNPs could be biomagnified from the second to third trophic level, but not from the first to second or third levels. Furthermore, the waterborne and trophic exposure of AgNPs considerably induced oxidative stress and reproductive toxicity. Together, this study demonstrated that AgNPs could be biomagnified across trophic chain and consequently cause trophic toxicity.

Silver nanoparticles induced hippocampal neuronal damage involved in mitophagy, mitochondrial biogenesis and synaptic degeneration

Silver nanoparticles (AgNPs) could accumulate in the central nervous system (CNS) and induce neurotoxicity for their widespread use in industry and medicine. Mitochondria are vulnerable to toxicity of AgNPs, however, their role in the neurotoxicity remains unclear. This study aimed to evaluate AgNPs-induced synaptic degeneration in mouse hippocampal neurons (at a dose of 12–120 mg/kg BW via intravenous injection), and to further investigate mechanism of mitophagy, mitochondrial biogenesis process in the neurotoxicity. The results indicated that AgNPs accumulated in mouse hippocampal neurons and induced neurological deficits of learning and memory, which involved in synaptic degeneration accompanied with mitochondrial damage. Mechanistically, AgNPs exposure increased protein expression of PTEN-induced kinase 1 (PINK1), Parkin and inhibited peroxisome proliferator-activated receptor coactivator 1 alpha (PGC-1α) protein expression, caused disturbed mitophagy and mitochondrial biogenesis. AgNPs also induced synaptic damage by increasing the protein expression of synaptophysin and decreasing PSD95, MAP2 protein expression. AgNPs exposure even promoted protein expression of amyloid precursor protein (APP) using in amyloid-β (Aβ) cleavage. Furthermore, AgNPs induced hippocampal neuronal synaptic degeneration, mitophagy and mitochondrial biogenesis is dependent on particle-specific AgNPs rather than released silver ions. Our research could provide insights into the regulatory mechanisms of AgNPs-induced neurotoxicity. This study will shed the light of neurotoxicological evaluation of nanoparticles and possible early warning of biomedical applications.

Analysis of Silver Nanoparticles for the Treatment and Prevention of Nucleopolyhedrovirus Affecting Bombyx mori.

Bombyx mori nucleopolyhedrovirus (BmNPV) causes major economic losses in sericulture. A number of agents have been employed to treat viral diseases. Silver nanoparticles (AgNPs) have wide applications in biomedical fields due to their unique properties. The anti-BmNPV effect of AgNPs has been evaluated, however, there are insufficient studies concerning its toxicity to other organisms and the environment. We chemically synthesized biocompatible BSA-AgNPs with a diameter range of 2–4 nm and characterized their physical properties. The toxicity of AgNPs towards cells and larvae with different concentrations was examined; the results indicated a biofriendly effect on cells and larvae within specific concentration ranges. The SEM observation of the surface of BmNPV after treatment with AgNPs suggested that AgNPs could destroy the polyhedral structure, and the same result was obtained by Coomassie blue staining. Further assays confirmed the weakened virulence of AgNPs-treated BmNPV toward cells and larvae. AgNPs also could effectively inhibit the replication of BmNPV in infected cells and larvae. In summary, our research provides valuable data for the further development of AgNPs as an antiviral drug for sericulture.

Cytotoxicity of nanomixture: Combined action of silver and plastic nanoparticles on immortalized human lymphocytes

BackgroundSilver nanoparticles (AgNP) are one of the most commercialized types of nanomaterials, with a wide range of applications owing to their antimicrobial activity. They are particularly important in hospitals and other healthcare settings, where they are used to maintain sterility of surfaces, textiles, catheters, medical implants, and more. However, AgNP can not only harm bacteria, but also damage mammalian cells and tissue. While the potential toxicity of AgNP is an understood risk, there is a lack of data on their toxicity in combination with polymeric materials, especially plastic nanoparticles such as polystyrene nanoparticles (PSNP) that can be released from surfaces of polystyrene devices during their medical use. AimThis study aimed to investigate combined effect of AgNP and nanoplastics on human immune response. MethodsCells were treated with a range of PSNP and AgNP concentrations, either applied alone or in combination. Cytotoxicity, induction of apoptosis, generation of oxidative stress, uptake efficiency, intracellular localization and nanomechanical cell properties were selected as exposure biomarkers. ResultsCollected experimental data showed that nanomixture induced oxidative stress, apoptosis and mortality of Jurkat cells stronger than its individual components. Cell treatment with AgNP/PSNP mixture also significantly changed cell mechanical properties, evidenced by reduction of cells’ Young Modulus. ConclusionAgNP and PSNP showed additive toxic effects on immortalized human lymphocytes, evidenced by increase in cellular oxidative stress, induction of apoptosis, and reduction of cell stiffness. These results have important implications for using AgNP and PSNP in medical contexts, particularly for long-term medical implants.

Low Concentrations of Silver Nanoparticles Inhibit Spore Germination and Disturb Gender Differentiation of Ceratopteris thalictroides (L.) Brongn

Because of their excellent antibacterial properties, silver nanoparticles (AgNPs) are widely used in all walks of life, which has caused them to be discharged into aquatic environments with possible negative effects on aquatic plants. In the present study, we used an aquatic fern, Ceratopteris thalictroides, as a model to investigate the effects of AgNPs on its spore germination, gametophytes, sex differentiation, and growth. The results demonstrated that AgNPs significantly inhibited spore germination of C. thalictroides at a AgNP concentration higher than 0.02 mg/L. Additionally, we found sex-dependent effects of AgNPs on the development and growth of the gametophyte of C. thalictroides. The proportion of hermaphrodites in the gametophytes and the area of gametophytes significantly decreased under AgNP treatment, while no significant effect was observed in the male gametophytes. Using the AgNP filtrate (without nanoparticles) and AgNPs plus cysteine (Ag+ chelator), we found that the release of Ag+ from nanoparticles was not the cause of the toxicity of AgNPs on C. thalictroides. The EC50 of AgNPs on spore germination was 0.0492 mg/L, thus indicating an ecological risk of AgNPs on this species even at concentrations lower than the Ag element concentration of the WHO guidelines for drinking-water quality.

Effects of environmental factor fulvic acid on AgNPs food chain delivery and bioavailability

Due to its antimicrobial activity, silver nanoparticles (AgNPs) have become the most commonly applied nanomaterials. However, the potential ecotoxicological toxicity of AgNPs in the environment is still unclear. Here we assessed the trophic transfer and toxicity of commercially manufactured polyvinyl pyrrolidone (PVP)-coated AgNPs using a model food chain from Escherichia coli (E. coli) to Caenorhabditis elegans (C. elegans). Our results demonstrated that AgNPs could be accumulated in E. coli and transferred to C. elegans that preyed on the bacteria. Although low concentration of AgNPs had no significant inhibition on E. coli, they could affect germ cell apoptosis, reproduction ability and population size of C. elegans through food chain. Importantly, natural organic matter (NOM), which is omnipresent in environmental system, could increase the accumulation of AgNPs in E. coli and C. elegans, and significantly enhance the ecotoxicity of AgNPs. Our findings indicated that potential risks of nanomaterial through food chain should be considered for higher trophic organisms. And environmental factors could play an important role in transport of nanomaterials and altering their accumulation and toxicity in ecosystem.

Roles of hemocyte subpopulations in silver nanoparticle transformation and toxicity in the oysters Crassostrea hongkongensis

Hemocytes are the main immune cells in bivalve mollusks and one of the sensitive targets for nanoparticle toxicity. Bivalve hemocytes consist of multiple functional heterogeneous cell types, but their different roles in immune system against foreign particles remain largely unknown. In order to clarify the different immune responses of hemocyte subpopulations to silver nanoparticles (AgNPs) and Ag ions, in this study, the Hong Kong oyster (Crassostrea hongkongensis) hemocytes were employed and separated into three subpopulations based on their cell size and granularity, including agranulocytes (R1), semigranulocytes (R2), and granulocytes (R3). We first demonstrated that AgNPs could rapidly enter into the oyster hemocytes within 3 h by phagocytosis process and resulted in different immune responses in hemocyte subpopulations. The most affected cell subtype by AgNPs was the granulocytes, followed by semigranulocytes, whereas agranulocytes were not affected following exposure to AgNPs. Interestingly, AgNPs induced the granule formation in semigranulocytes and further increased the proportion of granulocytes, whereas their ionic counterparts had no such effects on hemocyte composition, indicating the different detoxification mechanisms for nanoparticulate and ionic form. Following AgNP exposure, the dissolved Ag ions were accumulated in lysosomes and caused lysosomal dysfunction, indicating that lysosomes were the main targets for AgNP toxicity and the dissolved Ag ions were the main contributor of AgNP toxicity. Furthermore, AgNP exposure induced reactive oxygen production and impeded the lysosome function and phagocytosis in granulocytes, with impaired immunity system in oysters. Our study identified the different immune responses of oyster hemocyte subpopulations to AgNPs based on the in vitro short-term exposure assays, which may be applied to rapidly evaluate the ecotoxicological risks of different nanoparticles in aquatic systems.

Synthesis of &lt;i&gt;Padina tetrastromatica&lt;/i&gt; Seaweed Mediated Silver Nanoparticles and its Toxicological Evaluation against Brine Shrimp &lt;i&gt;Artemia&lt;/i&gt;

The present study evaluates the toxicity of AgNPs synthesised from Padina tetrastromatica (P-AgNPs) through Brine Shrimp Lethality Assay. The aqueous Padina seaweed extract was treated with AgNO3 to synthesise P-AgNPs, and these NPs were then characterised by multiple analytical techniques. The UV-Vis spectra displayed characteristic SPR peaks of AgNPs at about 409.5 nm. The TEM and particle size distribution results verified the formation of polydisperse spherical P-AgNPs with a dominant size of around 48 nm. Zeta potential analysis indicates the moderate stability of P-AgNPs. The FTIR spectrum of P-AgNPs reveals the presence of organic functional groups, suggesting the involvements of seaweed organic matters in capping and stabilising AgNPs. Though the 24-h mortality test showed a dose-dependent increase in Artemia death, the results imply a non-toxic property in P-AgNPs (LC50 value: 4300 mg/L; &gt;1000 mg/L). These findings conclusively suggest the acute exposure to P-AgNPs has no substantial risk to marine organisms.

Epidermal Growth Factor-labeled liposomes as a way to target the toxicity of silver nanoparticles into EGFR-overexpressing cancer cells in vitro

Silver nanoparticles (AgNPs) are the most toxic nanostructures for both cancer and healthy cells. Thus, their usefulness in the anticancer therapy is limited. Interestingly, the epidermal growth factor receptor (EGFR) is overexpressed in many cancer cells, e.g. in lung and tongue cancers. Therefore, the aim of this study was to develop a way to direct the cytotoxic effect of AgNPs against cancer cells, saving healthy ones by entrapping these NPs inside liposomes labeled with the epidermal growth factor (EGF-LipoAgNPs) and directing these structures into EGFR-overexpressing cancer cells. The obtained results showed spherical structures with a 107.9 nm size and − 16.60 mV zeta-potential. The UV–Vis scan and TEM images did not show free AgNPs in the solution. The obtained complexes were able to decrease the metabolic activity in the A549 and SCC-15 cells more effectively than native AgNPs. Furthermore, the ROS production, lactate dehydrogenase release, and caspase-9 and -3 activity were significantly increased after the treatment with EGF-LipoAgNPs for 24 and 48 h. The expression of genes encoding catalase, superoxide dismutase, and p53 protein increased significantly, while the KI67 gene expression decreased, especially in the A549 and SCC-15 cells. Moreover, the KI67 protein expression was lower than in the cells treated with native AgNPs, while catalase activity was decreased significantly after the treatment with the obtained complexes. In turn, SOD activity increased more efficiently in the EGFR-overexpressing cancer cells. In all tested parameters, EGF-LipoAgNPs exerted a lower toxic effect on the BJ cells than native AgNPs. Summarizing, the created liposomal system reduces the toxicity of AgNPs against normal human fibroblasts and enhances the toxic and proapoptotic effect of these NPs, which may be caused by improvement of their uptake by EGFR-overexpressing cancer cells.

Silver Nanoparticles Induce Apoptosis in HepG2 Cells through Particle-Specific Effects on Mitochondria.

Silver nanoparticles (AgNPs) have been widely used in biomedical and consumer products. It remains challenging to distinguish the toxicity of AgNPs derived from the particle form or the released silver ions (Ag+). In this study, the toxic effects of two citrate-coated AgNPs (20 and 100 nm) and Ag+ were investigated in hepatoblastoma cells (HepG2 cells). The suppression tests showed that AgNPs and Ag+ induced cell apoptosis via different pathways, which led us to speculate on the AgNP-induced mitochondrial damage. Then, the mitochondrial damages induced by AgNPs and Ag+ were compared under the same intracellular Ag+ concentration, showing that the mitochondrial damage might be mainly attributed to Ag nanoparticles but not to Ag+. The interaction between AgNPs and mitochondria was analyzed using a scattered light imaging method combined with light intensity profiles and transmission electron microscopy. The colocalization of AgNPs and mitochondria was observed in both NP20- and NP100-treated HepG2 cells, indicating a potential direct interaction between AgNPs and mitochondria. These results together showed that AgNPs induced apoptosis in HepG2 cells through the particle-specific effects on mitochondria.

Preparation and characterisation of ciprofloxacin-loaded silver nanoparticles for drug delivery.

Silver nanoparticles (AgNPs) have shown potential applications in drug delivery. In this study, the AgNPs was prepared from silver nitrate in the presence of alginate as a capping agent. The ciprofloxacin (Cipro) was loaded on the surface of AgNPs to produce Cipro‐AgNPs nanocomposite. The characteristics of the Cipro‐AgNPs nanocomposite were studied by X‐ray diffraction (XRD), UV–Vis, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier‐transform infra‐red analysis (FT‐IR) and zeta potential analyses. The XRD of AgNPs and Cipro‐AgNPs nanocomposite data showed that both have a crystalline structure in nature. The FT‐IR data indicate that the AgNPs have been wrapped by the alginate and loaded with the Cipro drug. The TEM image showed that the Cipro‐AgNPs nanocomposites have an average size of 96 nm with a spherical shape. The SEM image for AgNPs and Cipro‐AgNPs nanocomposites confirmed the needle‐lumpy shape. The zeta potential for Cipro‐AgNPs nanocomposites exhibited a positive charge with a value of 6.5 mV. The TGA for Cipro‐AgNPs nanocomposites showed loss of 79.7% in total mass compared to 57.6% for AgNPs which is due to the Cipro loaded in the AgNPs. The release of Cipro from Cipro‐AgNPs nanocomposites showed slow release properties which reached 98% release within 750 min, and followed the Hixson–Crowell kinetic model. In addition, the toxicity of AgNPs and Cipro‐AgNPs nanocomposites was evaluated using normal (3T3) cell line. The present work suggests that Cipro‐AgNPs are suitable for drug delivery.

Biosynthesis of silver nanoparticles from Pseudomonas fluorescens and their antifungal activity against Aspergillus niger and Fusarium udum

AbstractEmerging plant diseases have posed a significant danger to global economies in recent years. Fungicide resistance and climate change are the two primary sources of pathogen outbreaks. The silver nanoparticles (AgNPs) have been demonstrated to restrain pathogenic bacteria, fungi and viruses with minimal risk of developing resistance and phytotoxicity. The synthesis of silver nanoparticles via chemical and physical methods raises concerns about environmental safety and production costs. The microbial bio‐fabrication of silver nanoparticles is simple, cost‐effective and ready‐to‐use technology. We used Pseudomonas fluorescens cell filtrates to synthesise silver nanoparticles in the current investigation. The silver nanoparticles were characterised using Dynamic Light Scattering, zeta potential (ζ), UV‐Vis spectroscopy, surface plasmon resonance analysis and transmission electron microscopy (TEM). Both silver nanoparticles and AgNO3 were tested for their ability to inhibit two phytopathogenic fungi, that is, Fusarium udum and Aspergillus niger. Potent inhibition of mycelial growth was observed when silver nanoparticles were used at a concentration of 150 ppm. However, further research is needed to assess the toxicity of AgNPs before they are mass‐produced and used in agricultural applications.

Chromosomal aberrations, DNA damage, and biochemical disturbances induced by silver nanoparticles in mice: role of particle size and natural compounds treatment

Context Nanotechnology is widely used nowadays in several fields of industry, engineering, and medicine, the biological action mechanisms of AgNPs, which mainly involve the release of silver ions (Ag+), generation of reactive oxygen species (ROS). Objective The potential toxicity AgNPs of damages to hepatic cells, hesperidin, and naringin role for their protective effect against the increase of ROS due to AgNPs toxicity. They can be restored, most cellular biochemical parameters, genotoxicity, mutagenicity, and histopathological analysis. Materials and methods Toxicity was induced by an oral dose of Ag NPs of (20–100 nm) for one month, after that treated with hesperidin, naringin (100 mg/kg) for three weeks, malondialdehyde (MDA) levels, nitric oxide (NO), glutathione (GSH) and catalase were estimated. Also, aminotransferases (AST and ALT), alkaline phosphatase (ALP), γ-glutamyltransferase (GGT), albumin, and total bilirubin were determined, following Chromosomal aberrations, DNA breaks, and histological analyses Results hesperidin, and naringin treatment, recorded amelioration in most biochemical, genetic, and spermatogenesis disturbances Also, histological Investigations were improved. Conclusion Their biological safety problems, such as potential toxicity on cells, tissue, and organs should be paid enough attention, hesperidin and naringin amelioration fundamental alterations, as hepatic architectural and DNA damage, related to its role as an antioxidant and anti-inflammatory agent.

Potential application of Au core labeling for tracking Ag nanoparticles in the aquatic and biological system

The entering of silver nanoparticles (Ag NPs) in natural environments constantly increases due to their widespread production and application. While the environmental behavior, impacts, and fate of Ag NPs were critically assessed, the main challenge represents continuous tracking and quantification of Ag NPs in environmental and biological matrices. A group of labeled Ag NPs with gold cores (Au@Ag NPs) was developed for distinguishing between pristine Ag NPs and their other forms, and we comprehensively compared their physicochemical properties, environmental behavior, and biological effects with unlabeled Ag NPs. The electron transfer process from the Au core to the Ag shell gradually decreased with the increase of Ag shell thickness, then the inhibition of Ag+ release induced by the Au core was gradually alleviated, but the generation of superoxide radicals was intensified sharply. Then, the effect of the Au core on the dissolution capacity and free radicals' generation significantly altered the biological toxicity of Ag NPs, and the influence degree was related to the test organism's species. Nevertheless, the Au core retained the surface properties of Ag NPs, leading to the uptake of Au@Ag NPs, entirely consistent with the behavior of unlabeled Ag NPs. These findings confirmed that Au core labeling provides new opportunities for tracking Ag NPs in environmental and biological systems, and the exposure conditions and test organisms should be carefully assessed before employing the Au core labeling technology.

Unveiling changes of microbial community involved in N and P removal in constructed wetlands with exposing to silver nanoparticles

Constructed wetlands (CWs) are environmentally friendly engineered systems to purify wastewater, with low-cost and easy maintenance. However, it is not clear on responses of functional microbes for nitrogen (N) and phosphorus (P) biotransformation in CWs to silver nanoparticles (Ag NPs). The high throughput sequencings were employed to reveal microbial communities in vertical flow subsurface CWs with stable operation for 120 days. The results indicated that NH4+-N, TN and TP removal of soil layer decreased by 43.56%, 15.7% and 22.7% under stress of Ag NPs. Microbial richness index and compositions were affected, and control wetland enriched Sulfurospirillum, Desulfarculaceae and Flavobacterium whereas CWs exposed to Ag NPs enriched Desulfosporosinus and Desulfurispora from LEfSe analysis. Moreover, after dosing Ag NPs, relative abundances of functional genes amoA and hao for nitrification, nirK and norB for denitrification and ppx and phoA/phoD for phosphorus conversions in upper soil were significantly downregulated. Inhibition on functional bacteria and genes of Ag NPs explained poor removal efficiencies of nitrogen and phosphorus pollutants in CWs. Our findings give an insight into ecological toxicity of Ag NPs on CWs with N and P bioconversions and provide the understanding of response of nitrifiers, denitrifies and PAOs.

Edible mushroom extract engineered Ag NPs as safe antimicrobial and antioxidant agents with no significant cytotoxicity on human dermal fibroblast cells

This study aims to develop a novel biomaterial to combat microbial infections and oxidative stress without any adverse effects. Accordingly, a facile, eco-friendly, stable in time and non-toxic silver nanoparticles (Ag NPs) was synthesized using the extract of edible mushroom, Agaricus bisporus. The myco-synthesized Ag NPs were characterized by UV–Visible spectroscopy, X-ray diffraction (XRD), High-resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and Zeta potential. Ag NPs formation was confirmed by the appearance of brown colour due to surface plasmon resonance (SPR) effect. UV–Vis spectroscopy exhibited a sharp absorbance peak at 430 nm. XRD reflected the presence of diffraction peaks at (111), (200), (220) and (311) planes of face centred cubic (fcc) of Ag NPs. HR-TEM have shown the presence of spherical shaped particles with an average size of 16 nm. EDX spectrum for myco-synthesized Ag NPs recorded strong major intense signal at 0.3 keV and 3 keV confirming the presence of pure silver in the prepared Ag NPs. In antibacterial assay, the myco-synthesized Ag NPs have shown inhibition size against six selected human pathogens viz., Streptococcus pyogenes (17.36 ± 0.45 mm), Staphylococcus aureus (18.00 ± 0.33 mm), Klebsiella pneumoniae (16.84 ± 0.4 mm), Shigella flexneri (18.67 ± 0.66 mm), Candida albicans (19.00 ± 0.66 mm) and Aspergillus fumigatus (18.48 ± 0.53 mm). The myco-synthesized Ag NPs exhibited DPPH free radical scavenging activity and inhibited the free radicals up to 76.17 ± 0.01% with an IC50 value of 12.5 µg mL−1. No significant toxicity of myco-synthesized Ag NPs on normal human dermal fibroblast cells were noticed (87.2 ± 0.01% at 100 µg mL−1). The present work concludes that myco-fabricated Ag NPs could be used as a potential drug to control microbial infections of skin without causing any adverse effects on normal cells.

Photochemical effect of silver nanoparticles on flesh fly larval biological system

With the progress of nanoscience and its applications, silver nanoparticles (AgNPs) have become one of the most interesting nanoparticles owing to their use in different fields. However, the excessive use of AgNPs and its products may cause toxicity in both the environment and in human health. The main goal of this research is to study the toxic and photochemical effects of AgNPs against Sarcophaga argyrostoma larvae through ultrastructure, morphological change, and DNA damage. Treating midgut epithelium with AgNPs led to many alterations in dark conditions, disintegrated epithelium, swollen cells, and shrunken nucleus. Organelles appeared in a loose manner and mitochondria were without cristae, endoplasmic reticulum had dark spots, and peritrophic membrane was loose in appearance. Fatty tissues were vacuolized and muscle fibers lacked normal striations and had many gaps and lysosomal bodies. In the light conditions, the epithelium appeared with detached cells and many vacuoles, organelles were ruptured with many gaps in between, and secretory vesicles were scattered. Peritrophic membrane disappeared. Muscles collapsed and vacuolized loosed fatty tissues were detected. On the other hand, control larvae epithelium appeared regularly distinct, with organelles intact and muscles had clear normal striations. Data showed that AgNPs caused ultrastructural and morphological changes of the external cuticle of the 4th instar larvae along with a significant effect on DNA damage that occurred after the larval treatment, reflecting the toxicity of AgNPs.

Evaluation of the Toxicity of Silver Nanoparticle AgNP on Stages of Housefly, Musca domestica L.

The current study aimed to evaluate the toxicity of silver AgNPs nanoparticles by dipping and feeding methods and for five concentrations (800, 400, 200, 100, 50) ppm in the stages of the house fly Musca domestica L., the concentration of 800 ppm caused an emergence inhibition rate of 100 %, while the lowest inhibition rate was at a concentration of 50 ppm, which amounted to 36% by immersion method after ten days of treatment, while the value of LC50 (the concentration that kills 50% of insects) reached (422.711) ppm. While the percentage of inhibition by feeding method reached 93% at a concentration of 800 ppm, and the concentration of 50 ppm gave the lowest inhibition rate of 43% and for the same time period, and the value of LC50 (794.099) ppm. For both methods. The results also showed that all concentrations had an effect on the natural development of the growth of the different stages and caused the appearance of deformations in the pupa and the adult and a decrease in the percentage of the appearance of the adult. The results showed that the effect of silver nanoparticles by dipping method was higher than by feeding method for all phases.

Polystyrene microplastics sunlight-induce oxidative dissolution, chemical transformation and toxicity enhancement of silver nanoparticles

The coexistence of microplastics (MPs) and nanomaterials has been increasingly studied, but the influence of MPs on the chemical transformation of nanomaterials remains unclear. Herein, it was demonstrated that polystyrene (PS) MPs induce the oxidative dissolution, transformation and toxicity of silver nanoparticles (Ag NPs) under simulated sunlight irradiation. The PS MPs induced the oxidation dissolution of pristine Ag NPs by 1O2, OH and/or acid release and simultaneously reduced the released Ag+ to secondary Ag NPs by O2−. The sizes, functional groups and ageing status of the PS MPs and pH characterized secondary Ag NPs formation. Secondary formation of Ag NPs induced by PS MPs also occurred in realistic water and was governed by dissolved organic matter (DOM) and Cl−, rather than SO42− or CO32−. Moreover, PS MPs remarkably promoted Ag+ release, altered the Ag+:Ag0 ratio, and presented vehicle effects on Ag+ toxicity to Daphnia magna. The concentration addition model demonstrated that the ion-related toxicity of Ag NPs was significantly increased by PS MPs. Therefore, PS MPs induced the oxidative dissolution, transformation and toxicity enhancement of Ag NPs under sunlight irradiation, and accordingly, the coexistence of PS MPs and Ag NPs in freshwater environments should be seriously considered.