Toxicity Of ZnO Nanoparticles Research Articles

Influence of multi-walled carbon nanotubes on the toxicity of ZnO nanoparticles in the intestinal histopathology, apoptosis, and microbial community of common carp

In recent years, carbon nanotubes (CNTs) have gained tremendous attention due to their widespread application. Previous research indicated that carbon nanomaterials can affect the toxicity of some pollutants. In this study, we investigated the influence of multi-walled CNTs (MWCNTs) on the toxicity of ZnO nanoparticles (ZnONPs) in the intestine of common carp (Cyprinus carpio). After four-week exposure, histopathological observation and TUNEL assay showed concentration ratio-dependent intestinal lesions and apoptosis, with the most severe in the HSC-ZnONPs group (50 mg L−1 ZnONPs and 2.5 mg L−1 MWCNTs), less severe in the ZnONPs group (50 mg L−1 ZnONPs) and the least in the LSC-ZnONPs group (50 mg L−1 ZnONPs and 0.25 mg L−1 MWCNTs). Furthermore, ICP-OES indicated that intercellular zinc accumulation was significantly decreased by the presence of the MWCNTs, which suggested the varied contribution of ZnONPs to intestine injury in different groups. Moreover, 16 s rDNA sequencing revealed that ZnONPs alone and in combination with MWCNTs significantly altered the microbial community diversity and composition of the gut microbiota compared with controls. In addition, the predominant phylum, class, order, family, and genus were significantly different among these groups. In conclusion, the influence of MWCNTs on the toxicity of ZnONPs was related to the concentration and concentration ratio of the mixture.

Chronic effects induced by zinc oxide nanoparticles against larvae of the northern house mosquito Culex pipiens (Diptera: Culicidae)

It is estimated that up to a million person are subject to death every year from mosquito-borne diseases. To avoid the epidemic situations arising from mosquito-borne diseases, it is necessary to reduce the mosquito populations. Challenges against efficient mosquito management are mainly related to emergence of insecticide resistance leading to increased need for the development of alternative methods. Ideal insecticides cause permanent impacts on the target insects in order to ensure powerful insecticidal effect. This study hypothesized that the impact of zinc oxide nanoparticles (ZnONPs) on the larvae of Culex pipiens Linnaeus, 1758 (Diptera: Culicidae) mosquito is irreversible and chronic. The first instar C. pipiens larvae were treated with a sublethal concentration (LC20, 0.24 g/L) of ZnONPs for 72 h and then allowed to recover for additional 72 h. Following the recovery period, the changes in zinc accumulation, growth rate, gut ultrastructure, biochemical changes in the hydrogen peroxide, antioxidant and detoxification enzymes were recorded and compared between recovered larvae and untreated (control). Recovered larvae showed significant increase in the accumulated zinc and reduced growth rate by about 50% compared to untreated (control). Furthermore, the ultrastructure of the alimentary canal epithelium showed several forms of pathological signs in different parts of the midgut of recovered larvae. Treatment with ZnONPs induced oxidative stress (OS) which appeared in the form of significant increase in hydrogen peroxide concentration. In response to OS, insects activate the detoxification system to get rid of the toxic nanoparticles. The detoxification enzyme alkaline phosphatase (ALP) and the antioxidant enzyme glutathione peroxidase (GPX) were inhibited while superoxide dismutase (SOD) was activated against ZnONPs toxicity. Additionally, recovered larvae didn’t show differences in the catalase activity from untreated control. These results verified that ZnONPs induce chronic impacts on C. pipiens larvae suggesting that it can be used in their management via direct application in standing water sources including accumulated rains and swimming pools.

Plant mediated-green synthesis of zinc oxide nanoparticles: An insight into biomedical applications

Abstract Green synthesis of zinc oxide (ZnO) nanoparticles (NPs) using various plant extracts as reducing and capping agents has gained attention in recent research. The green synthesis of ZnO NPs offers several advantages such as being simple, eco-friendly, safe, cost-effective, and reproducible approach with high stability. Hence, this article provides an overview of zinc metal and ZnO compounds, and traditional chemical and physical synthesis of ZnO NPs with primary focuses on the green synthesis of ZnO NPs. This study discusses various plant extracts used and the proposed mechanisms in the green synthesis of ZnO NPs. Additionally, it explores the cytotoxic mechanisms of the green-synthesized ZnO NPs and addresses the various biomedical applications of ZnO NPs, including antibacterial, anticancer, antidiabetic, antioxidant, antifungal, antiviral, antiparasitic, anti-inflammatory, and wound healing. Moreover, the review critically discusses the toxicity of ZnO NPs and emphasizes the need for more toxicological studies to ensure the safety and facilitate the risk assessments and risk management of ZnO NPs. Furthermore, this review underlines the challenges associated with the translation process of ZnO NPs from bench to market, including the complex and time-consuming regulatory approval process for ZnO NPs, which requires a multidisciplinary approach involving scientists, regulators, and manufacturers.

Free zinc ions, as a major factor of ZnONP toxicity, disrupts free radical homeostasis in CCRF-CEM cells

Nanotechnology has become a ubiquitous part of our everyday life. Besides the already-known nanoparticles (NPs), plenty of new nanomaterials are being synthesized every day. Here, we explain the mechanism of the zinc oxide nanoparticles (ZnONPs) cytotoxicity in a cellular model of acute lymphoblastic leukaemia (CCRF-CEM). To do so, we investigated both possible hypotheses about the ZnONPs mechanism of toxicity: a free zinc ions release and/or reactive oxygen species (ROS) generation. Presented here results show that:A)EDTA protects the cells, whereas a common antioxidant agent (NAC) enhances the cytotoxic effect induced by ZnONPs,B)ZnONPs release zinc ions in vitro,C)ZnONPs upregulate the activity of antioxidative defence enzymes, which are Nrf2 transcription factor-dependent,D)The upregulation of ROS generation is correlated with the upregulation of reductive stress markers,E)ZnONPs treatment induces NADPH oxidases that cause excessive production of superoxide radicals in tested cellular model.Our results support the hypothesis that the mechanism of ZnONPs cytotoxicity is based on the release of free zinc ions. Nevertheless, both previously quoted hypotheses incompletely described the mechanism of action of ZnONPs. In this paper, we show that the mechanism of cytotoxicity of ZnONPs is based on the induction of reductive stress in CCRF-CEM cells, which is caused by free zinc ions released from ZnONPs. Therefore, the increase of oxidative stress markers is most likely a secondary response of the cells towards the Zn2+. These results provide a crucial expansion of the zinc ion hypothesis and thus explain the biphasic cellular response of CCRF-CEM cells treated with ZnONPs.

Toxicological effects of zinc oxide nanoparticles on hemato-biochemical profile of common carp (Cyprinus carpio)

Nanoparticles (NPs) are considered a major risk for aquatic ecosystemss, and zinc oxide nanoparticles (ZnO-NPs) are among generally utilized NPs in the modern era. Aquatic life cannot escalate away from the negative effects of NPs. This study aimed to evaluate the toxicity of ZnO-NPs on the the hemato-biochemical profile of Cyprinus carpio (C. carpio). 150C. carpio fish were tested; they had average weights of 108 g, lengths of 21.65 cm, and acclimated to typical living conditions while maintaining pH, temperature, and fresh aerations. Fish were given intraperitoneal injections (2–3 cm) deep into the abdominal cavity and were exposed to ZnO-NPs through aquatic means. Fish were exposed to biosynthesized ZnO-NPs via intraperitoneal injection at T4, 10, 15, and 20 ml/g body weight of fish and aquatic mode of exposure at T0, 0.00, T1, 1.00, T2, 2.00, and T3, 3.00 mg/L to each aquarium, respectively. The findings of the investigation demonstrated that exposure to ZnO NPs caused considerable modifications in the hematological and biochemical parameters of the fish. The hematological examination revealed significant changes in the RBC count, Hb, and Hct levels, which indicated the possibility of detrimental impacts on the fish's ability to transport oxygen. The biochemical study revealed significant shifts in the levels of serum total protein, albumin, globulin, and glucose, which pointed to the possibility of harm to the fish's liver and kidney functions. According to the findings of the study, exposure to ZnO nanoparticles can induce considerable variations in the hemato-biochemical profile of common carp, which indicates that there may be possible dangers to their general health and survival. The findings of this study underline the need of regulating the usage of these nanoparticles as well as their disposal in order to reduce the possible impact that they could have on aquatic ecosystems and on public health. The findings also highlight the need for more research to properly understand the effects of ZnO NPs on the health of fish and the ecosystem over the long term. In conclusion, the research makes a contribution to our understanding of the possible concerns connected with the use of ZnO NPs in a variety of industries and provides vital insights into the toxicological effects that these nanoparticles have on aquatic creatures. The findings could potentially be used to influence regulatory decisions on the use and disposal of ZnO NPs, with the objective of limiting the potential dangers that these particles pose to the environment and to public health.

Combined cytotoxicity of ZnO nanoparticles and chlorpyrifos in the rainbow trout, Oncorhynchus mikyss, gonadal cell line RTG-2

The toxicity of ZnO nanoparticles (ZnO NPs) in aquatic organisms has been extensively studied, but little information is available on the effects associated with their interaction with other contaminants. In this context, the in vitro effects of co-exposure of chlorpyrifos (CPF) and ZnO NPs on fish-derived cells were investigated. A selection of concentrations was tested in single and binary exposures: CPF (0.312 - 75 mg/L) and ZnO NPs (10 - 100 mg/L). Cytotoxicity was measured using commonly used cellular endpoints: Alamar Blue/CFDA-AM for viability and plasma membrane integrity, NRU for lysosomal disruption and MTT for mitochondrial function. In addition, specific mechanisms of toxicity for CPF and ZnO NPs were tested: acetylcholinesterase (AChE) activity and ROS generation, respectively. AChE was by far the most sensitive assay for single exposure to CPF. There was no concentration-response relationship for ROS after single exposure to ZnO NPs, but 10 mg/L produced significant effects only for this cellular endpoint. Co-exposure of CPF with 10 m/L of ZnO NPs produced significant effects in almost all endpoints tested, which were enhanced by co-exposure with 100 mg/L of ZnO NPs. AChE testing of additional co-exposures with bulk ZnO, together with the application of the Independent Action (IA) prediction model, which allowed us to draw more in-depth conclusions on the toxicological behavior of the mixture. Synergism was observed at 0.625 mg/L CPF concentration and antagonism at 5 mg/L CPF in mixtures containing 100 mg/L of both ZnO NPs and bulk ZnO. However, more cases of synergism between CPF and ZnO NPs occurred at intermediate CPF concentrations, demonstrating that nano-sized particles have a more toxic interaction with CPF than bulk ZnO. Therefore it can be argued that in vitro assays allow the identification of interaction profiles of NP-containing mixtures by achieving multiple endpoints with a large number of concentration combinations.

Interactive effects of temperature and salinity on toxicity of zinc oxide nanoparticles towards the marine mussel Xenostrobus securis

Growing application of zinc oxide nanoparticles (ZnO-NPs) in global market has led to the concern over their potential environmental impacts. Filter feeders like mussels are prone to nanoparticles due to their superior filter-feeding ability. Temperature and salinity of coastal and estuarine seawaters often vary seasonally and spatially, and their changes may jointly influence physicochemical properties of ZnO-NPs and thus their toxicity. This study, therefore, aimed to investigate the interactive effect of temperatures (15, 25 and 30 °C) and salinities (12 and 32 PSU) on physicochemical properties and sublethal toxicity of ZnO-NPs towards a marine mussel Xenostrobus securis, and to compare that with the toxicity caused by Zn2+ ions (zinc sulphate heptahydrate). The results revealed increased particle agglomeration but decreased zinc ion release of ZnO-NPs at the highest temperature and salinity condition (30 °C and 32 PSU). After exposure, ZnO-NPs significantly reduced survival, byssal attachment rate and filtration rate of the mussels at high temperature and salinity (30 °C and 32 PSU). Glutathione S-transferase and superoxide dismutase activities in the mussels were suppressed at 30 °C. These aligned with the augmented zinc accumulation with increasing temperature and salinity which could likely be attributable to increased particle agglomeration of ZnO-NP and enhanced intrinsic filtration rate of the mussels under these conditions. Together with the observed lower toxic potency of Zn2+ compared to ZnO-NPs, our results suggested that the mussels might accumulate more zinc through particle filtration under higher temperature and salinity, eventually resulting in elevated toxicity of ZnO-NPs. Overall, this study demonstrated the necessity to consider the interactive effect of environmental factors such as temperature and salinity during the toxicity assessment of nanoparticles.

Short-Term Toxicity of ZnO Nanoparticles on Microalgae at Different Initial Nutrient Concentrations

The aim of this work was to investigate the combined short-term toxic effect of zinc oxide (ZnO) nanoparticles (NPs) and nitrate concentration of the medium on freshwater microalgae. For this purpose, freshwater microalgae Chlorococcum sp. was cultivated in modified Blue-Green medium (BG-11) containing nitrate concentrations ranging from 0 to 300 mg/L, and exposed to ZnO NPs in different concentrations (0.081 to 810 mg/L) for a period up to 96 h. The experimental results revealed that algal growth was affected by the exposure time, NPs concentrations, and mainly the initial nitrate concentration. Differences in microalgae growth rates were observed. The toxic effect of ZnO NPs was higher on microalgae cultured in modified BG-11 with low and high nitrate concentrations. During the 4-day exposure, the highest growth rates were observed at 24 h at an initial nitrate concentration of 50 mg/L; 1.94 d−1 and 0.22 d−1 for 0 and 810 mg/L ZnO NPs, respectively. Nitrate uptake by algal biomass reached up to 40.1% after 96 h of operation in the control culture with an initial nitrate concentration of 50 mg/L. Finally, the results of this study showed the need for the investigation of ZnO NPs toxicity on microalgae under optimum and stressful nutrient conditions for microalgae growth.

EVALUATION THE HEPATOPROTECTIVE EFFECT OF QUERCETIN AGAINST ZINC OXIDE NANOPARTICLES INDUCED TOXICITY IN MOUSE MODEL

Quercetin is a well-known flavonoid that resents in fruits and vegetables. Zinc oxide nanoparticles (ZnO-NPs) are widely used for packing and cosmetics. This study was conducted to determine the effect of Quercetin on the liver by ZnO-NPs toxicity in a mouse model. Thirty-six Swiss albino mice were divided into two groups, i.e. control group and the experimental group. The control group was administered saline for 28 days orally. The experimental group is further divided into three groups. To the first one, only ZnO-NPs (30 mg/kg, orally) were given for 28 days. To the second group, only quercetin (100 mg/kg, orally) was given for 28 consecutive days. To the third, a combination of quercetin and ZnO-NPs was given for alternate 28 days through the oral route. Animals were sacrificed after 14 and 28 days of dosing. Mouse liver was fixed in the 10% formalin to preserve organ integrity. Histopathological analysis was done to observe the structure of liver in treated mice. The ZnO-NPs group shows the central vein full of infiltrations, sinusoidal spaces congestions and some the necrosis of hepatocytes was observed. The quercetin group shows a normal central vein with no infiltrations. The animals that received both quercetin and ZnO-NPs showed infiltration in central vein and necrosis but less than that of only ZnO-NPs given group. Full recovery in the liver structure was observed in the quercetin+ZnO-NPs group after 28 days of treatment. This study showed the hepatoprotective effect of quercetin because it reduces the toxicity produced by ZnO-NPs.

ZnO Nanorods Create a Hypoxic State with Induction of HIF-1 and EPAS1, Autophagy, and Mitophagy in Cancer and Non-Cancer Cells.

Nanomaterials are gaining increasing attention as innovative materials in medicine. Among nanomaterials, zinc oxide (ZnO) nanostructures are particularly appealing because of their opto-electrical, antimicrobial, and photochemical properties. Although ZnO is recognized as a safe material and the Zn ion (Zn2+) concentration is strictly regulated at a cellular and systemic level, different studies have demonstrated cellular toxicity of ZnO nanoparticles (ZnO-NPs) and ZnO nanorods (ZnO-NRs). Recently, ZnO-NP toxicity has been shown to depend on the intracellular accumulation of ROS, activation of autophagy and mitophagy, as well as stabilization and accumulation of hypoxia-inducible factor-1α (HIF-1α) protein. However, if the same pathway is also activated by ZnO-NRs and how non-cancer cells respond to ZnO-NR treatment, are still unknown. To answer to these questions, we treated epithelial HaCaT and breast cancer MCF-7 cells with different ZnO-NR concentrations. Our results showed that ZnO-NR treatments increased cell death through ROS accumulation, HIF-1α and endothelial PAS domain protein 1 (EPAS1) activation, and induction of autophagy and mitophagy in both cell lines. These results, while on one side, confirmed that ZnO-NRs can be used to reduce cancer growth, on the other side, raised some concerns on the activation of a hypoxic response in normal cells that, in the long run, could induce cellular transformation.

Review of Zinc Oxide Nanoparticles: Toxicokinetics, Tissue Distribution for Various Exposure Routes, Toxicological Effects, Toxicity Mechanism in Mammals, and an Approach for Toxicity Reduction.

Zinc oxide (ZnO) nanoparticles (NPs) are widely used as a sunscreen, antibacterial agent, dietary supplement, food additive, and semiconductor material. This review summarizes the biological fate following various exposure routes, toxicological effects, and toxicity mechanism of ZnO NPs in mammals. Furthermore, an approach to reduce the toxicity and biomedical applications of ZnO NPs are discussed. ZnO NPs are mainly absorbed as Zn2+ and partially as particles. Regardless of exposure route, elevated Zn concentration in the liver, kidney, lungs, and spleen are observed following ZnO NP exposure, and these are the target organs for ZnO NPs. The liver is the main organ responsible for ZnO NP metabolism and the NPs are mainly excreted in feces and partly in urine. ZnO NPs induce liver damage (oral, intraperitoneal, intravenous, and intratracheal exposure), kidney damage (oral, intraperitoneal, and intravenous exposure) and lung injury (airway exposure). Reactive oxygen species (ROS) generation and induction of oxidative stress may be a major toxicological mechanism for ZnO NPs. ROS are generated by both excess Zn ion release and the particulate effect resulting from the semiconductor or electronic properties of ZnO NPs. ZnO NP toxicity can be reduced by coating their surface with silica, which prevents Zn2+ release and ROS generation. Due to their superior characteristics, ZnO NPs are expected to be used for biomedical applications, such as bioimaging, drug delivery, and anticancer agents, and surface coatings and modification will expand the biomedical applications of ZnO NPs further.

The toxicity of ZnO and CuO nanoparticles on biological wastewater treatment and its detoxification: a review

The wide use of ZnO and CuO nanoparticles in research, medicine, industry, and other fields has raised concerns about their biosafety. It is therefore unavoidable to be discharged into the sewage treatment system. Due to the unique physical and chemical properties of ZnO NPs and CuO NPs, it may be toxic to the members of the microbial community and their growth and metabolism, which in turn affects the stable operation of sewage nitrogen removal. This study summarizes the toxicity mechanism of two typical metal oxide nanoparticles (ZnO NPs and CuO NPs) to nitrogen removal microorganisms in sewage treatment systems. Furthermore, the factors affecting the cytotoxicity of metal oxide nanoparticles (MONPs) are summarized. This review aims to provide a theoretical basis and support for the future mitigating and emergent treatment of the adverse effects of nanoparticles on sewage treatment systems.

ZnO Nanoparticles Synthesis, Toxicity, Delivery systems and Bio medical applications

In recent decades, metal oxide nanoparticles have acquired relevance in biology and medicine due to their unique physicochemical properties. Because of its cheap cost, biodegradability and low toxicity, zinc oxide nanoparticles (ZnO-NPs) have attracted a lot of interest from researchers for therapeutic and diagnostic applications. Zinc oxide (ZnO) has been studied for various biological applications due to its unique semiconducting, optical and piezoelectric characteristics. The growing interest in nano zinc oxide has led to the discovery and development of nanoparticle production technologies. ZnO nanocomposites with varied morphologies have recently been prepared using a physical and chemical method. ZnO NPs have also been employed to deliver different bioactive and chemotherapeutic anticancer medicines to tumour cells in a targeted and sustained manner. This review discusses on the properties, synthesis, drug delivery method for cancer treatment and many other biological uses of ZnO NPs.

Biosynthesized ZnO-NPs Using Sea Cucumber (Holothuria impatiens): Antimicrobial Potential, Insecticidal Activity and In Vivo Toxicity in Nile Tilapia Fish, Oreochromis niloticus

In this study, a sustainable and eco-friendly method was used to prepare zinc oxide nanoparticles (ZnO-NPs) using a sea cucumber aqueous extract. Then, ZnO-NPs were characterized by instrumental analysis (UV-vis, HR-TEM, XRD, FT-IR, and DLS) and evaluated for their possible antibacterial, antifungal, and insecticidal activities. Additionally, the toxicity of ZnO-NPs was evaluated in vivo against Nile Tilapia (Oreochromis niloticus). The sea cucumber was collected from the Gulf of Suez (Red Sea) at Al-Ain Al-Sokhna coast in Egypt and identified as Holothuria impatiens. The prepared Hi-ZnO-NPs peaked at 350 nm in UV–Vis spectral analysis. They showed quasi-spherical shaped particles with sizes ranging from 13 nm to 47 nm and a predominate size of 26 nm as indicated by HR-TEM. The XRD pattern of Hi-ZnO-NPs revealed a crystalline phase with an average size of 17.2 nm as calculated by Debye–Scherrer equation. FTIR analysis revealed the possible role of H. impatiens biological molecules in the biosynthesis process of ZnO-NPs. Hi-ZnO-NPs showed a negative zeta potential of −19.6 mV, demonstrating moderate stability. Biosynthesized Hi-ZnO-NPs revealed broad antimicrobial activity against Gram-positive bacteria (S. aureus ATCC 25923 and E. feacalis), Gram-negative bacteria (S. typhi, K. pneumonia and E. coli), and filamentous fungi (Aspergillus niger). Hi-ZnO-NPs demonstrated larvicidal activity against the mosquito, Culex pipiens (LC50 = 2.756 ppm and LC90 = 9.294 ppm), and adulticidal action against the housefly, Musca domestica (LD50 = 4.285 ppm and LD90 = 22.847 ppm). Interestingly, Hi-ZnO-NPs did not show mortality effects against Nile tilapia fish (Oreochromis niloticus), highlighting the potential safety of Hi-ZnO-NPs to highly exposed, non-target organisms. However, histopathological and hematological investigations provided dose-dependent impacts of Hi-ZnO-NPs to Nile tilapia. Overall, data provide an eco-friendly approach for synthesizing novel Hi-ZnO-NPs with multiple biomedical properties and potentially low toxicity to Nile tilapia fish.

Salinity Moderated the Toxicity of Zinc Oxide Nanoparticles (ZnO NPs) towards the Early Development of Takifugu obscurus

ZnO nanoparticles (ZnO NPs) have been applied in a wide range of fields due to their unique properties. However, their ecotoxicological threats are reorganized after being discharged. Their toxic effect on anadromous fish could be complicated due to the salinity fluctuations during migration between freshwater and brackish water. In this study, the combined impact of ZnO NPs and salinity on the early development of a typical anadromous fish, obscure puffer (Takifugu obscurus), was evaluated by (i) observation of the nanoparticle characterization in salt solution; (ii) quantification of the toxicity to embryos, newly hatched larvae, and larvae; and (iii) toxicological analysis using biomarkers. It is indicated that with increased salinity level in brackish water (10 ppt), the toxicity of ZnO NPs decreased due to reduced dissolved Zn2+ content, leading to higher hatch rate of embryos and survival rate of larvae than in freshwater (0 ppt). The irregular antioxidant enzyme activity changes are attributed to the toxic effects of nanoparticles on CAT (catalase), but further determination is required. The results of present study have the significance to guide the wildlife conservation of Takifugu obscurus population.

The influence of ZnO nanoparticles on horizontal transfer of resistance genes in lab and soil conditions

Antibiotic resistance is a severe problem that threatens the achievements of modern medicine. Metallic nanoparticles may promote the horizontal transfer of resistance genes due to their toxicity to bacterial cells and metal-induced co-selection mechanisms. In this study, we investigated the toxicity of ZnO nanoparticles to E. coli DH5α laboratory strain and the abundance of soil microbial community. Moreover, the influence of ZnO nanoparticles on resistance gene transfer in laboratory and soil conditions was evaluated. ZnO nanoparticles at concentrations up to 10 mg L−1 reduced the survival of E. coli cells by 14.6% and increased the transformation frequency by almost 1.8 fold. In soil, ZnO nanoparticles at a concentration of 1000 mg kg−1 affected the total abundance of bacteria, causing a decrease in the 16S rRNA gene copy number. We did not detect the presence of 11 target antibiotic resistance genes (sul1, sul2, imp2, imp5, blaCTX-M, ermB, mefA, strB, aadA1, tetA1, tetB), which confer resistance to five classes of antibiotics in soil treated with ZnO nanoparticles. No elevated conjugation frequency was observed in soil microbial communities treated with ZnO nanoparticles. However, the increase in czcA gene copies indicates the spread of genetic elements harbouring metal resistance. The data shows that metallic nanoparticles promote the spread of antibiotic and metal resistance genes. The broad implication of the present research is that the inevitable nanoparticles environmental pollution may lead to the further dissemination of antibiotic resistance and profoundly influence public health.

Influence of Surface Coating towards the Controlled Toxicity of ZnO Nanoparticles In Vitro

The uncertainties in ZnO-mediated toxicity and particle stability in a biological system remain a challenge and mitigate against deployment as next-generation nanoparticles (NPs), especially in biomedical applications. With that perspective, the present study investigates the surface chemical properties of ZnO NPs coated with three different surfactant biomolecules, namely polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS) to control the toxicity-induced potentials. On the testing of the surface-functionalized ZnO NPs, notable changes in the particle sizes, morphology, zeta potential, and hydrodynamic size compared to the pure ZnO NPs are observed. In addition, FTIR spectroscopy, TGA, XRD, XPS, and HRTEM analysis showed significant changes in the surface structures and surface functional groups of the three different ZnO NPs on surface functionalization. Following the physical characterization, the cell viability of rat liver BRL-3A-treated ZnO–PEG, ZnO–CTAB, and ZnO–SDS compared to pure ZnO NPs (<50%) falls between 70% and 95% in a dose-determined manner. The cells treated with the pure ZnO NPs showed a higher percentage of apoptotic cells (~61%), which is significantly higher than the 3.4%, 1.5%, and 0.6% for ZnO–PEG-, ZnO–CTAB-, and ZnO–SDS-treated cells (respectively). Furthermore, the surface functionalization was significantly observed to reduce the content of reactive oxygen species (ROS) to 13.6%, 9.7%, and 2.6% compared to the content level of ~71% from the pure ZnO-treated cells. Besides the marked impairment of mitochondrial potentials induced by the pure ZnO NPs, the surfactant–ZnO NPs were observed to slow down the induction of DNA fragmentation and retain the structural integrity of mitochondrial membranes. The toxicity effects are controlled in the order of ZnO–SDS > ZnO–CTAB > ZnO–PEG, i.e., anionic > cationic > non-ionic. Overall from the analysis, the study stresses the importance of having a suitable surface ligand for the ZnO NPs so as to use them in the biomedical sector.

Ameliorative Effects of Vitamins A, C, and E on Sperm Parameters, Testis Histopathology, and Oxidative Stress Status in Zinc Oxide Nanoparticle-Treated Rats.

One of the most often utilized nanoparticles (NPs) in several technologies is zinc oxide (ZnO) NPs. However, these NPs are said to have harmful effects on the reproductive system. Thus, we designed this study to specify the potential preventive activity of vitamins (Vits) A, C, and E, as antioxidants, against toxicity of ZnO NPs in the testes of rats. A total of 54 Wistar rats were arranged in 9 groups of 6 and then orally received water (control 1), olive oil (control 2), Vit A (1000 IU/kg), Vit C (200 mg/kg), Vit E (100 IU/kg), ZnO (200 mg/kg), ZnO+Vit A, ZnO+Vit C, and ZnO+Vit E. To determine the amount of testicular injury, sperm analysis and histological evaluation were performed. In addition, oxidative stress status was examined using colorimetric and qRT-PCR methods. Our findings suggest that ZnO NPs cause adverse effects on sperm parameters and testicular histology. Furthermore, oxidative biomarkers (malondialdehyde and total oxidant capacity) were enhanced in the ZnO group. By contrast, the gene expression and activities of antioxidant enzymes (SOD, GPx, and CAT) noted a remarkable decrease in the ZnO group regarding control (p < 0.05). However, oxidative markers were remarkably mitigated after combined treatment of ZnO NPs and Vits A, C, or E compared to the rats given ZnO NPs (p < 0.05). Additionally, compared to the ZnO NP group, the rats receiving Vits+ZnO NPs exhibit increased antioxidant enzyme activity and mRNA expression (p < 0.05). The findings demonstrate the abovementioned Vits' ameliorative effects on toxicity incurred by ZnO NPs.

TOXICITY OF ZINC OXIDE TO SCLERACTINIAN CORALS AND ZOOXANTHELLAE: A BRIEF REVIEW

In recent years, the safety of sunscreens to coral reefs and the role these products would play in the process of coral bleaching has been a concern. However, the discussion centers almost exclusively on the organic components used as UV filters, with little attention given to inorganic UV filters, such as zinc oxide. Zinc oxide nanoparticles (ZnO-NPs) have been a common ingredient of sunscreen formulations for decades and are being discharged in coral reef environments. Even though there are data supporting that ZnO is toxic to certain species of fish and algae, regulatory agencies do not appear concerned with the possible outcome of the exposure of corals and their algal symbionts to this metal oxide. This review compiles the published work on the toxicity of ZnO and ZnO-NPs to corals and zooxanthellae, which strongly supports the notion that zinc oxide is toxic to both corals and microalgae. In view of this, concern has been raised by the use of the “reef safe” label to promote sunscreens that lack specific organic components, however containing ZnO as the major UV filter.

Potential role of dietary parsley and/or parsley nanoparticles against zinc oxide nanoparticles toxicity induced physiological, and histological alterations in Nile tilapia, Oreochromis niloticus

In the recent study, Nile tilapia, Oreochromis niloticus was exposed to sublethal concentration of Zinc Oxide nanoparticles (ZnO-NPs) (8 mg/L) to study the toxic influence on biochemical and oxidative stress biomarkers. Also, the protective role of dietary parsley leaves and parsley nanoparticles was evaluated. Fish were divided into 6 groups of 3 replicates as follows: group I: was served as control, group II: was fed free basal diet containing parsley leaves (4 g/kg of diet). group III: was fed diet containing parsley nanoparticles (4 g/kg of diet). group IV: exposed to (8 mg/L) ZnO-NPs and fed on basel diet for 6 weeks. group V: exposed to (8 mg/L) ZnO-NPs and fed on parsley leaves (4 g/kg of diet). group VI: exposed to (8 mg/L) ZnO-NPs and fed on parsley nanoparticles (4 g/kg diet) for 6 weeks. At the end of experiment, blood and liver tissues were collected for biochemical analysis and histopathological investigation. Results exhibited significant (p < 0.05) increase in the levels of urea, creatinine, total protein, albumin, globulin, glucose, cortisol, cholesterol, and IgM during ZnO-NPs exposure for 6 weeks. Concurrent with those changes, marked decrease (p < 0.05) in serum triglycerides and IgG levels were observed. On the other hand, the histopathological alterations of the examined liver of tilapia intoxicated with ZnO-NPs showed severe congestion, necrosis and apoptosis of hepatic cells, and marked activation of kupffer cells with mononuclear inflammatory cellular infiltration mainly lymphocytes were prevalent. Intake of parsley and parsley nanoparticles in groups (V & VI) after exposure to ZnO –NPs ameliorated hyperglycemia, total protein and lipid profiles, and blunted the increase in cortisol and modulated the levels of urea, creatinine, and IgM of ZnO –NPs treated fish, and enhanced the hepatic architecture of tilapia fish fed on parsley and nano parsley. The obtained results revealed that the dietary parsley leaves and parsley nanoparticles reduced the influence of ZnO-NPs toxicity on Nile tilapia which was more evidence in fish fed on parsley nanoparticles. It could be concluded that parsley has a hepatoprotective effect in tilapia fish against ZnO-NPs toxicity.