Toxic Effects Of Silver Nanoparticles Research Articles

Administration of vitamin E and C enhances immunological and biochemical responses against toxicity of silver nanoparticles in grass carp (Ctenopharyngodon idella).

The aim of the current study was to evaluate the toxic effect of silver nanoparticles (Ag-NPs) on biochemical biomarkers, immune responses, and the curative potential effects of vitamin C and E on grass carp. Fish (n = 420) with an average initial body weight of 8.045 ± 0.13 g were shifted to glass aquaria (36 x 18 x 18 inches, filled with 160-L tap water) in triplicates. Aquaria were randomly designated as A, B, C, D with alone Ag-NPs (Control (0), 0.25, 0.50, 0.75 mg/L) and E, F, G with Ag-NPs + Vit. C + Vit. E (0.25+0.25+0.25, 0.50+0.50+0.50, 0.75+0.75+0.75 mg/L). NPs particles were administrated viz, oral and intravenous routes for 7 days. The results indicated that both routes had non-significant effect, but levels of Ag-NPs had significant effect. Treatments C, D and G showed significant decrease in levels of RBC, HGB and HCT except for WBC and NEUT levels, which significantly increased. ALT, ALP, AST, urea, and creatinine showed significant increase in activity in the C, D, and G groups. CAT, SOD decreased significantly in all Ag-NPs alone groups, while significantly increased with vitamin E and C. LYZ, TP, ALB, GLB showed significant low activity in the B, C, and D groups while significantly high activity in the E, F, and G groups. Cortisol, glucose and triglycerides showed significant increase in the B, C, and D groups, while E, F, and G groups showed significant low levels of triglycerides, COR, and GLU. Cholesterol level was same across all treatment groups. In conclusion, vitamin E and C as powerful antioxidants protect the fish against Ag-NPs except high dose level of 0.75mg/L, while 0.25mg/L of Ag-NPs was presumably safe for C. idella.

Assessment of Reproductive Toxicity of Silver Nanoparticles on Male Albino Mice "Mus musculus"

Regarding the fast development of nanotechnology and its various applications, the present study was carried out to estimate the potential toxic effect of silver nanoparticles (AgNPs) on the fertility of male albino mice. Thirty-five adult male mice were randomly divided into 5 groups (7 mice per group) as the following: the first group (GP

Green synthesis and characterization of silver nanoparticles for reducing the damage to sperm parameters in diabetic compared to metformin

The present study used physics to synthesize silver nanoparticles using aqueous extract of fresh garlic as reducing and as a stabilizing agent silver nitrate solution. This method has proven to be environmentally friendly and safe for the synthesis of stable silver nanoparticles. The acquisition of silver nanoparticles was confirmed by optical detection, that is, by changing the color of the liquid to transparent orange and then blackish brown. Then, the characterization was confirmed using other assays. In this study, it was found that the absorption peak of silver nanoparticles was at a wavelength of 420 nm and the particle size ranged between [50–350] nm. The surface roughness of silver oxide/silver nanoparticles was 9.32 nm with an average square roughness of 21.19 nm, and the energy dispersive spectra showed that the absorption peak was in the region of 3 keV, indicating that the nanoparticles contained crystalline silver. In this study, the stability of the silver nanoparticles was good, as ZP reached (− 19.5). The results confirm that the conductivity increases with the increase in frequency due to the high energy of the photons, which causes the electrons to vibrate in the energy levels and thus increase the energy in the mitochondria and increase the movement of sperm in the Diabetic mice treated with doses of silver nanoparticles. The toxic effect of silver nanoparticles has been evaluated in other studies, in addition to evaluating antioxidants, antifungals, treating cancer cells, regulating cholesterol levels, the effect of these nanoparticles on sex cells in pregnant female mice, heart tension, and many other tests. In this study, the activities and efficacy of silver nanoparticles on sperms were determined in male mice with diabetes caused by STZ, and the treatment period was long (35 days) so that the evaluation period was a complete life cycle of male sex cells and within a long period of time and at an average nano size. This has not been studied in other previous studies. The results indicate that the biosynthesis of silver nanoparticles using garlic plant led to positive results on sperm treatments by contributing to an increase in the number of sperm with reactivation and a decrease in abnormalities in addition to a decrease in mortality due to diabetes. This is evidence that the synthesis of silver nanoparticles using garlic plant size (50–350 nm) can treat impotence and be used in the future in the treatment of many diseases without side effects.

Dynamic responses of carbon metabolism of sediment microbial communities to Ag nanoparticles: Effects of the single and repeated exposure scenarios

The widespread use of nanosilver will inevitably lead to their release into aquatic environment, threating the health of freshwater ecosystem. The toxic effects of silver nanoparticles (AgNPs) on sediment microbial diversity, community composition, and functional enzyme activity are well established, while little is known about how sediment microbes dynamically respond to the stress of different AgNPs exposure scenarios. Herein, microcosm experiments were performed to investigate the impacts of repeated (1 mg/L, applied every 6 days for 10 times) and single (10 mg/L) exposure scenarios of AgNPs on the specific functions of sediment microbes (5–60 days). The carbon metabolism of sediment microbial communities was measured using BIOLOG ECO microplates, and carbon metabolic rate and functional diversity indices were calculated. Compared to control group, the maximum carbon source utilization capacity of the microbial community increased by 6.6 and 15.4 % in the single and repeated exposure group, respectively. And the metabolic rates of sediment microorganisms were significant increased by 6.1 % in the repeated exposure group, which suggested that repetitive low-dosing of AgNPs induce a larger alteration of both capacity and rate of microbial carbon metabolism. Notably, different AgNPs exposure scenarios resulted in a shift in the carbon source preference of the microorganisms. After exposure for 60 days, compared with the controls, the ability to utilize polymers was significantly increased by 51.5 and 21.7 % in the single and repeated exposure groups, respectively, and decreased by 33.7 and 10.5 % in the utilization of miscellaneous, both exhibiting significant differences (P < 0.05), implying that AgNPs exposure scenarios affected the microbial-mediated carbon cycling processes in sediment. These results highlight that different exposure scenarios of AgNPs have different effects on the carbon metabolism capacity of microbial communities, thus affecting the carbon cycling processes in which microorganisms are involved.

Effectiveness of hesperidin against toxic effect of silver nanoparticles on the brain via apoptotic/antiapoptotic pathway in adult albino rats

Effectiveness of hesperidin against toxic effect of silver nanoparticles on the brain via apoptotic/antiapoptotic pathway in adult albino rats

Toxicity of silver nanoparticles on Achromobacter denitrificans: effect of concentration, temperature and coexisting anions.

The indoor culture method was carried outto study the toxic effect of silver nanoparticles (AgNPs) on Achromobacter denitrificans.Specifically, the effects of AgNPsconcentration, temperature and coexisting anions were analyzed.The results showed that AgNPs exerted significant inhibition on the bacteria, which was closelycorrelated with its concentrationand temperature. Both the ammoniaoxidationand generationcapacityof Achromobacter denitrificansdecreased significantlywith an increase in AgNPsconcentration. Compared with the inhibition performance at 30 °C, NH4+-N generation rates decreased by 45.31% at 20 °C and 17.58% at 40 °C, respectively, revealing that too low or too high temperature induced toreduce the nitrogen conversion ability of Achromobacter denitrificans.While compared with temperature, the effect of coexistingions (Cl- and SO42-) was not significant(P > 0.05). Electron microscopy observations found that AgNPs non-specifically boundto the cells (content ranging from 0.04% to 0.10%) and actedon the cell surface structure, causingwrinkles,depressions, and ruptures on the surface of cell membranes, and leakage of substances in the membranes. AgNPs increasedthe rate of cell apoptosis and decreasedthe cell body volumemainly with short-term acute effects.

Proteomic profiling reveals mitochondrial toxicity of nanosilver and silver nitrate in the gill of common carp

Mitochondria are recognized as an important target organelle for the toxicity of nanomaterials. Although the toxic effects of silver nanoparticles (AgNPs) on mitochondria have been widely reported, the mechanism behind the toxicity remains unclear. In this study, the effects of two forms of silver (AgNPs and AgNO3) on carp gill mitochondria were investigated by analyzing the mitochondrial ultrastructure, physicochemical properties of mitochondrial membrane, and mitochondrial proteomics. After exposure of common carp to AgNPs (0.75 mg/L) and AgNO3 (0.05 mg/L) for 96 h, both forms of silver were shown to cause gill mitochondrial lesions, including irregular shape, loss of mitochondrial cristae, and increased mitochondrial membrane permeability. Proteomics results revealed that AgNPs and AgNO3 induced 362 and 297 differentially expressed proteins (DEPs) in gill mitochondria, respectively. Among the DEPs, 244 were shared between AgNPs and AgNO3 treatments. These shared proteins were mainly distributed in the mitochondrial membrane and matrix, and were significantly enriched in the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathway. The functional annotation of DEPs induced by both silver forms was mainly involved in energy production and conversion. These results indicated that the toxic mechanism of AgNPs and AgNO3 on gill mitochondria were comparable and the two forms of silver caused mitochondrial dysfunction in fish gills by inhibiting the TCA cycle and disrupting the electron transport chain.

The Antibacterial and Cytotoxic Effects of Silver Nanoparticles Coated Titanium Implants: A Narrative Review.

Nanotechnology has become an emerging research field with numerous biomedical scientific applications. Silver possesses bactericidal activities that have been harnessed for centuries; however, there is a concern about the toxic effects of silver nanoparticles. This paper aims to provide an overview of silver-treated dental implants and discuss their potential to reduce the prevalence of peri-implant diseases. An electronic search was performed using PubMed. After screening, data extraction was performed on the 45 remaining articles using inclusion and exclusion criteria. Most of the articles demonstrated that silver nanoparticles embedded in a coating layer and/or on surface-treated titanium exhibit sound antibacterial effects and biocompatibility. Most of the reviewed studies revealed that silver nanoparticles on dental implant surfaces reduced cytotoxicity but provided a prolonged antibacterial effect. The cytotoxicity and antibacterial effect are closely linked to how the silver nanoparticles are released from the titanium surfaces, where a slower release increases cell viability and proliferation. However, to improve the clinical translation, there is still a need for more studies, especially evaluating the long-term systemic effects and studies recreating the conditions in the oral cavity.

Silver nanoparticles: safety and efficiency for human health

Over the past few decades, nanoparticles of metals, and in particular silver, with a diameter of less than 100 nm have significantly expanded their field of application for various biomedical purposes. So, silver nanoparticles have great potential in a wide range of applications as antimicrobial agents, coatings for biomedical products, carriers for drug delivery, bioengineering, since they have discrete physical properties and wide biochemical functionality. Studies have shown that the size, morphology, stability and properties (chemical and physical) of metal nanoparticles are strongly influenced by the conditions of the experiment, the kinetics of the interaction of metal ions with reducing agents and the adsorption processes of the stabilizer with metal nanoparticles. This review aims to analyze the use of silver nanoparticles in modern medicine based on data from domestic and foreign literature over the past five years. The study confirmed the high biological activity of drugs with nanoserebrum as anti-inflammatory, antimicrobial agents, antifungals, the presence of an inhibitory effect on protozoa, antioxidant and anticancer effects, and substantiated the relevance of use in bioengineering and dentistry. However, rapid advances and advances in technology have led to concerns about the potential risk associated with the use and application of silver nanoparticles to human health and the environment. Therefore, this review attempts to characterize and quantify the potential harmful effects of silver nanoparticles on the health of laboratory animals and humans, and focuses on ways to neutralize or reduce the toxic effects of silver nanoparticles on the human body.

Integration of transcriptomics and metabolomics reveals damage and recovery mechanisms of fish gills in response to nanosilver exposure.

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

The Effects of Oral Silver Nanoparticles and Propolis on the Level of Lipid Peroxidation in Male Wistar Rats

Background: Oxidative stress is a leading factor in developing silver nanoparticle-induced toxicity. Objective: This study evaluated the effects of oral prescription of different doses of silver nanoparticles and propolis on lipid peroxidation in male Wistar rats. Methods: The male Wistar rats were randomly divided into four groups. Control group and three different treatment groups with oral prescription of 30 ppm, 60 ppm, and 60 ppm of silver nanoparticles with 200 mg/kg of propolis. The serum level of Malondialdehyde (MDA) was measured by Thiobarbituric Acid Reactive Substances (TBARS) assay using Thiobarbituric Acid (TBA). Results: The serum level of MDA as a marker of lipid peroxidation in the control group was 1.92 mM/mL, and in other groups that received silver nanoparticles (30 ppm, 60 ppm, 60 ppm with 200 mg/kg propolis) were respectively 2.82, 3.83 and 2.62 mM/mL. MDA level also increased at the doses of 30 ppm and 60 ppm compared to the control group and decreased when propolis was prescribed with silver nanoparticles in the third group; however, its value did not reach the level of the control group. Minimal levels of serum lipid peroxidation were observed when silver and propolis nanoparticles were administered to male rats. Conclusion: The mixture of silver nanoparticles and propolis reduces the toxic effects of silver nanoparticles; it preserves and increases the efficiency of this compound in medical applications.

Toxicity, biotransformation and bioaccumulation of silver nanoparticles in laboratory conditions and aquatic ecosystems

Generalized studies of the world scientific literature on the fate and risk assessment of exposure to silver nanoparticles (NPAg) both at the ecosystem level and at the organism level, as well as in the laboratory. It is emphasized that the toxic effect of silver nanoparticles, mechanisms and methods of action of NPAg on the body of aquatic organisms have been sufficiently studied in laboratory practice. However, there are some gaps and discrepancies between the results of laboratory tests and the study of real environmental consequences, and such inconsistencies hinder the development of appropriate effective measures to achieve environmental well-being. To bridge such gaps, this review summarizes how environmental conditions and the physicochemical properties of NPAg influence conflicting conclusions between laboratory and real-world environmental studies. It is emphasized that modern research on the pathways of entry, transformation and bioaccumulation of silver nanoparticles in natural aquatic ecosystems emphasizes the ability of such nanoparticles to penetrate intact physiological barriers, which is extremely dangerous. It is proved that silver nanoparticles have a toxic effect on microorganisms, macrophytes and aquatic organisms. The toxic effects of NPAg cover almost entire aquatic ecosystems. A study by a number of authors on the factors influencing the mobility, bioavailability, toxicity and environmental fate of Ag nanoparticles was analyzed to assess the environmental risk. In addition, this review systematically examines the various toxic effects of silver nanoparticles in the environment and compares these effects with the results obtained in laboratory practice, which is useful for assessing the environmental effects of such compounds. The dangerous chronic effects of low-concentration NPAg (μg/l) on natural aquatic ecosystems over a long period of time (months to several years) have been described in detail. In addition, the prospects for future studies of NPAg toxicity in natural freshwater environments are emphasized. Key words: nanoparticles of the medium (NPAg), ecosystem, laboratory wash, toxicity, aquatic organisms, ecological factors.

The Toxic Effect of Silver Nanoparticles on Nerve Cells: A Systematic Review and Meta-Analysis.

Despite the increasing use of silver nanoparticles in medical sciences, published studies on their interaction with nerve cells and evaluation of risks are dispersed. This systematic review and meta-analysis could be used to devise safety guidelines for the use of silver nanoparticles in industry and medicine to reduce adverse effects on the CNS.After extensive searches, the full text of 30 related studies was reviewed and data mining completed. Data were analyzed by calculating the mean of different ratios between treated and untreated groups. Linear regression between variables was evaluated by meta-regression. Subgroup analysis was also performed due to heterogeneity.Treatment with silver nanoparticles significantly reduced cell viability (SMD=-1.79%; 95% CI: -2.17 to -1.40; p<0.0001). Concentration>0.1μg/mL could kill neurons, while lower concentration would not (SMD -0.258; 95% CI: -0.821 to 0.305; p=369). In addition to the concentration, the coating, size of the nanoparticles, and cell type are also factors that influence SNP nerve cell toxicity. Measurement of apoptosis (SMD=2.21; 95% CI: 1.62 to 2.80; p=0.001) and lactate dehydrogenase release rate (SMD=0.9; 95% CI: 0.33 to 1.47; p<0.0001) also confirmed the destructive effect of silver nanoparticles on nerve cells.

Low Concentrations of Silver Nanoparticles and Silver Ions Perturb the Antioxidant Defense System and Nitrogen Metabolism in N2-Fixing Cyanobacteria.

Although toxic effects of silver nanoparticles (AgNPs) on aquatic organisms have been extensively reported, responses of nitrogen-fixing cyanobacteria to AgNPs/Ag+ under environmentally relevant concentrations are largely unknown. Here, cyanobacteria were exposed to different concentrations of AgNPs (0.01, 0.1, and 1 mg/L) or Ag+ (0.1, 1, and 10 μg/L) for 96 h. The impacts of AgNPs and Ag+ on photosynthesis and N2 fixation in cyanobacteria (Nostoc sphaeroides) were evaluated. In addition, gas chromatography-mass spectrometry (GC-MS)-based metabolomics was employed to give an instantaneous snapshot of the physiological status of the cells under AgNP/Ag+ exposure. Exposure to high doses of AgNPs (1 mg/L) or Ag+ (10 μg/L) caused growth inhibition, reactive oxygen species overproduction, malondialdehyde accumulation, and decreased N2 fixation. In contrast, low doses of AgNPs (0.01 and 0.1 mg/L) and Ag+ (0.1 and 1 μg/L) did not induce observable responses. However, metabolomics revealed that metabolic reprogramming occurred even at low concentrations of AgNP and Ag+ exposure. Levels of a number of antioxidant defense-related metabolites, especially phenolic acid and polyphenols (gallic acid, resveratrol, isochlorogenic acid, chlorogenic acid, cinnamic acid, 3-hydroxybenzoic acid, epicatechin, catechin, and ferulic acid), significantly decreased in response to AgNPs or Ag+. This indicates that AgNPs and Ag+ can disrupt the antioxidant defense system and disturb nitrogen metabolism even at low-dose exposure. Metabolomics was shown to be a powerful tool to detect "invisible" changes, not observable by typical phenotypic-based endpoints.

BIOSYNTHESIS, CHARACTERIZATION, BACTERICIDAL AND TOXIC EFFECT OF SILVER NANOPARTICLES USING Klebsiella pneumoniae STRAIN STC1

Nanotechnology dealt with nanoparticles having a size of 1-100nm used significantly in pharmaceutical science and many other fields. The use of microorganisms in the synthesis of nanoparticles emerged as an eco-friendly method. Klebsiella pneumoniae strain STC1 was isolated from cow’s milk and identified by 16S rRNA sequencing. The biosynthesis was done using the fixed ratio of aqueous solution of the bacterial supernatant and AgNO3 and the colour change was observed which proved the formation of silver nanoparticles. The nanoparticles were characterized by UV-Visible Spectrophotometer, FTIR, XRD and SEM. The nanoparticles were found to have sizes ranging from 15 to 70nm. The antibacterial activity of silver nanoparticles was studied against methicillin resistant Staphylococcus aureus, Clostridium perfringens, Pseudomonas sp. and Proteus sp. The Minimum Inhibitory Concentration of silver nanoparticles was found to be 50µg/ml against methicillin resistant Staphylococcus aureus. The synergistic effect of the silver nanoparticles with commercial antibiotics erythromycin and tetracycline was found to be more evident. The time kill assay and the cytoplasm diffusion assay showed the effectiveness of synthesized silver nanoparticles in the study. The synthesized silver nanoparticles had a great antibacterial potential against methicillin resistant Staphylococcus aureus. The toxic effect of silver nanoparticles revealed that as the concentration of the silver nanoparticles increased, the effect of toxicity increased and the hatching percentage of Artemia cysts decreased. The innovation in this present study is that the biosynthesis of nanoparticles is simple, cost effective, providing good bactericidal and cytotoxic activity and it can represent a future for more therapeutic and pharmacological applications.

Anti-Toxoplasma Effects of Silver Nanoparticles Based on Ginger Extract: An in Vitro Study

Background: Toxoplasmosis is a tropical disease that is opportunistic in immunocompromised patients. Objectives: In this research, our goal was to assess the anti-parasitic effect of silver nanoparticles (Ag-NPs) based on ginger extract on T. gondii tachyzoites. Methods: This study was conducted to assess the effects of various concentrations of nanoparticles on the parasite using light microscopy. The MTT assay was also conducted to evaluate the toxic effects of silver nanoparticles based on ginger extract on macrophage cells. In addition, the potential apoptosis of T. gondii by silver NPs was assessed using the flow cytometry technique. Results: Based on the tachyzoite assay using microscopic examination, it was observed that the higher the NPs concentration and the longer the parasite’s exposure to NPs, the greater the lethal effect of NPs on tachyzoites. The IC50 (inhibitory concentration) for NPs against T. gondii tachyzoites was 2 ppm. Also, according to the MTT assay, the 40 ppm concentration of nanoparticles had the most toxic impact on macrophages. Moreover, silver NPs led to apoptosis in approximately 55.22% of tachyzoites based on the flow cytometry technique. Conclusions: Based on the above results, it is concluded that silver nanoparticles based on ginger extract have a lethal effect on T. gondii and induce apoptosis in this parasite. This study encourages further studies in vivo.

Physiological and morphological responses of green microalgae Chlorella vulgaris to silver nanoparticles

The toxic effects of silver nanoparticles (AgNPs) on the physiology and morphology of the green microalga Chlorella vulgaris were studied. AgNPs were characterized by particle size distribution, ζ potential measurement, and atomic force microscopy (AFM). Chlorella vulgaris was exposed to 90–1440 μg/L of AgNPs range in Bold's Basal Medium for 96 h. The inhibition of algae growth rate and changes in the concentrations of chlorophyll-a, chlorophyll-b, pheophytin, and carotenoids was determined at the beginning and end of the trial. Cell diameter and volume, carbohydrate, total lipids, and protein content were also determined. Our data strongly suggest that the toxic effects of the AgNPs resulted in concentration and time-dependent. AgNPs altered C. vulgaris growth kinetics and cell metabolism expressed in photosynthetic pigments and biochemical composition. Our study confirmed the cytotoxicity of AgNPs through the algal growth inhibition with an EC50 value of 110 μg/L. Also, changes of chlorophyll-a, chlorophyll-b, pheophytin, and carotenoids concentrations were observed associated with a color shift from green to pale brown of algae cultures exposed to AgNPs for 96 h. Furthermore, algae cell concentration, diameter, and volume, plus total lipid, protein, and carbohydrates contents in the presence of AgNPs, were significantly altered compared to untreated cells. In synthesis, this study highlighted AgNPs toxic effects on morphological and physiological traits of C. vulgaris and warns about possible impacts on energy flow and aquatic food web structure, and on the transfer efficiency of energy to higher trophic levels.

Evaluation of the toxic effect of silver nanoparticles and the possible protective effect of ascorbic acid on the parotid glands of albino rats: Anin vivostudy

This study aimed to evaluate the toxic effect of silver nanoparticles (AgNPs) on the parotid glands (PGs) of albino rats histologically and ultrastructurally and assess the possible protective effect of ascorbic acid as an antioxidant. Thirty male albino rats weighing between 150 mg and 200 mg were divided into three groups: the control group (C1) contained 10 rats that received 2 mg/kg (body weight (bw)) of aqueous nitrate buffer by intraperitoneal (IP) injection daily for 28 days; the AgNPs group contained 10 rats that received 2 mg/kg (bw) IP AgNPs daily for 28 days; and the AgNPs-vitamin C group contained 10 albino rats that received 2 mg/kg (bw) AgNPs IP daily for 28 days with oral administration of 100 mg/kg (bw) vitamin C in drinking water daily for 28 days. The PG acinar and ductal cells of the AgNPs group showed signs of toxicity and degeneration characterized as pleomorphic nuclei, binucleation, cytoplasmic vacuolations, and stagnated secretion in the ductal lumen. In addition to degenerated mitochondria, dilated rough endoplasmic reticulum and lysosomes were filled with AgNPs (p < 0.001). The AgNPs-vitamin C group showed significantly less degenerative changes histologically and ultrastructurally compared to the AgNPs group (p = 0.002). AgNPs produced significant toxic effects on the PG of albino rats, presumably through the generation of reactive oxygen species and toxic ion release, and administration of vitamin C was shown effective in decreasing these toxic effects.

Products of Lipid Peroxidation as a Factor in the Toxic Effect of Silver Nanoparticles.

In our previous study we have shown that nanoparticles have different effects depending on the energy metabolism of the cell, which is an important factor in the context of oncology and diabetes. Here we assess the influence of AgNPs on cellular lipid components in varying glucose concentrations. To assess the effect of silver nanoparticles on cell lipids, we measured cell viability, the fluidity of the cell membranes, the content of amino groups in proteins, the level of lipid peroxidation products, the concentration of 4-hydroxynonenal (4-HNE), and the concentration of lipid peroxides. The obtained results show differences in the formation of lipid peroxidation products in cells exposed to oxidative stress induced by nanoparticles. In addition, we have shown that the metabolic state of the cell is a factor significantly affecting this process.

Changes in syntrophic microbial communities, EPS matrix, and gene-expression patterns in biofilm anode in response to silver nanoparticles exposure

Understanding the toxic effect of silver nanoparticles (AgNPs) on various biological wastewater treatment systems is of significant interest to researchers. In recent years, microbial electrochemical technologies have opened up new opportunities for bioenergy and chemicals production from organic wastewater. However, the effects of AgNPs on microbial electrochemical systems are yet to be understood fully. Notably, no studies have investigated the impact of AgNPs on a microbial electrochemical system fed with a complex fermentable substrate. Here, we investigated the impact of AgNPs (50 mg/L) exposure to a biofilm anode in a microbial electrolysis cell (MEC) fed with glucose. The volumetric current density was 29 ± 2.0 A/m3 before the AgNPs exposure, which decreased to 20 ± 2.2 A/m3 after AgNPs exposure. The biofilms produced more extracellular polymeric substances (EPS) to cope with the AgNPs exposure, while carbohydrate to protein ratio in EPS considerably increased from 0.4 to 0.7. Scanning electron microscope (SEM) imaging also confirmed the marked excretion of EPS, forming a thick layer covering the anode biofilms after AgNPs injection. Transmission electron microscope (TEM) imaging showed that AgNPs still penetrated some microbial cells, which could explain the deterioration of MEC performance after AgNPs exposure. The relative expression level of the quorum signalling gene (LuxR) increased by 30%. Microbial community analyses suggested that various fermentative bacterial species (e.g., Bacteroides, Synergistaceae_vadinCA02, Dysgonomonas, etc.) were susceptible to AgNPs toxicity, which led to the disruption of their syntrophic partnership with electroactive bacteria. The abundance of some specific electroactive bacteria (e.g., Geobacter species) also decreased. Moreover, decreased relative expressions of various extracellular electron transfer associated genes (omcB, omcC, omcE, omcZ, omcS, and pilA) were observed. However, the members of family Enterobacteriaceae, known to perform a dual function of fermentation and anodic respiration, became dominant after biofilm anode exposed to AgNPs. Thus, EPS extraction provided partial protection against AgNPs exposure.