Toxic response of nickel nanoparticles in human lung epithelial A549 cells

A Comparative Study on the Interaction Between Protein and PET Micro/Nanoplastics: Structural and Surface Characteristics of Particles and Impacts on Lung Carcinoma Cells (A549) and Staphylococcus aureus

The interaction between particles and proteins is a key factor determining the toxicity responses of particles. Therefore, this study aimed to examine the interaction between the emerging pollutant polyethylene terephthalate micro/nanoplastics from water bottles with bovine serum albumin. The physicochemical characteristics of micro/nanoplastics were investigated using nuclear magnetic resonance, x-ray diffraction, Fourier transform infrared, dynamic light scattering, and x-ray energy dispersive spectroscopy after exposure to various concentrations and durations of protein. Furthermore, the impact of protein-treated micro/nanoplastics on biological activities was examined using the mitochondrial activity and membrane integrity of A549 cells and the activity and biofilm production of Staphylococcus aureus. The structural characteristics of micro/nanoplastics revealed an interaction with protein. For instance, the assignment of protein-related new proton signals (e.g., CH2, methylene protons of CH2O), changes in available protons s (e.g., CH and CH3), crystallinity, functional groups, elemental ratios, zeta potentials (-11.3 ± 1.3 to -12.4 ± 1.7 to 25.5 ± 2.3 mV), and particle size (395 ± 76 to 496 ± 60 to 866 ± 82 nm) of micro/nanoplastics were significantly observed after protein treatment. In addition, the loading (0.012-0.027 mM) and releasing (0.008-0.013 mM) of protein also showed similar responses with structural characteristics. Moreover, the cell-based responses were changed regarding the structural and surface characteristics of micro/nanoplastics and the loading efficiencies of protein. For example, insignificant mitochondrial activity (2%-10%) and significant membrane integrity (12%-28%) of A549 cells increased compared with control, and reductions in bacterial activity (5%-40%) in many cases and biofilm production specifically at low dose of all treatment stages (13%-46% reduction) were observed.

The pulmonary effects of nickel-containing nanoparticles: Cytotoxicity, genotoxicity, carcinogenicity, and their underlying mechanisms

With the exponential growth of the nanotechnology field, the global nanotechnology market is on an upward track with fast-growing jobs. Nickel (Ni)-containing nanoparticles (NPs), an important class of transition metal nanoparticles, have been extensively used in industrial and biomedical fields due to their unique nanostructural, physical, and chemical properties. Millions of people have been/are going to be exposed to Ni-containing NPs in occupational and non-occupational settings. Therefore, there are increasing concerns over the hazardous effects of Ni-containing NPs on health and the environment. The respiratory tract is a major portal of entry for Ni-containing NPs; thus, the adverse effects of Ni-containing NPs on the respiratory system, especially the lungs, have been a focus of scientific study. This review summarized previous studies, published before December 1, 2023, on cytotoxic, genotoxic, and carcinogenic effects of Ni-containing NPs on humans, lung cells in vitro, and rodent lungs in vivo, and the potential underlying mechanisms were also included. In addition, whether these adverse effects were induced by NPs themselves or Ni ions released from the NPs was also discussed. The extra-pulmonary effects of Ni-containing NPs were briefly mentioned. This review will provide us with a comprehensive view of the pulmonary effects of Ni-containing NPs and their underlying mechanisms, which will shed light on our future studies, including the urgency and necessity to produce engineering Ni-containing NPs with controlled and reduced toxicity, and also provide the scientific basis for developing nanoparticle exposure limits and policies.

Effect of the Graphene- Ni/NiFe2O4 Composite on Bacterial Inhibition Mediated by Protein Degradation

Recent investigations have demonstrated that nickel ferrite nanoparticles and their derivatives have toxicity effects on bacterial cells. In this study, we have prepared nickel ferrite nanoparticles (Ni/NiFe₂O₄) and nickel/nickel ferrite graphene oxide (Ni/NiFe₂O₄-GO) nanocomposite and evaluated their toxic effects on E. coli cells ATCC 25922. The prepared nanomaterials were characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry techniques. The toxicity was evaluated using variations in cell viability, cell morphology, protein degradation, and oxidative stress. Ni/NiFe₂O₄-GO nanocomposites likewise prompt oxidative stress proved by the age of reactive oxygen species (ROS) and exhaustion of antioxidant glutathione. This is the first report indicating that Ni/NiFe₂O₄-GO nanocomposite-initiated cell death in E. coli through ROS age and oxidative stress.

Nanoparticle-based toxicity in perishable vegetable crops: Molecular insights, impact on human health and mitigation strategies for sustainable cultivation

With the advancement of nanotechnology, the use of nanoparticles (NPs) and nanomaterials (NMs) in agriculture including perishable vegetable crops cultivation has been increased significantly. NPs/NMs positively affect plant growth and development, seed germination, plant stress management, and postharvest handling of fruits and vegetables. However, these NPs sometimes cause toxicity in plants by oxidative stress and excess reactive oxygen species production that affect cellular biomolecules resulting in imbalanced biological and metabolic processes in plants. Therefore, information about the mechanism underlying interactions of NPs with plants is important for the understanding of various physiological and biochemical responses of plants, evaluating phytotoxicity, and developing mitigation strategies for vegetable crops cultivation. To address this, recent morpho-physiological, biochemical and molecular insights of nanotoxicity in the vegetable crops have been discussed in this review. Further, factors affecting the nanotoxicity in vegetables and mitigation strategies for sustainable cultivation have been reviewed. Moreover, the bioaccumulation and biomagnification of NPs and associated phytotoxicity can cause serious effects on human health which has also been summarized. The review also highlights the use of advanced omics approaches and interdisciplinary tools for understanding the nanotoxicity and their possible use for mitigating phytotoxicity.

Evaluation of In Vitro Cytotoxic, Genotoxic, Apoptotic, and Cell Cycle Arrest Potential of Iron-Nickel Alloy Nanoparticles

The use of iron-nickel alloy nanoparticles (Fe-Ni ANPs) is increasing daily in various fields. People are increasingly exposed to these nanoparticles for occupational and environmental reasons. Our study determined some of the effects of Fe-Ni ANP exposure and impacts on human health at the cellular level. The cytotoxic and genotoxic potentials of Fe-Ni ANPs were investigated by XTT, clonogenic, comet, and GammaH2AX analyses using Beas-2B cells. Annexin V, multicaspase, and cell cycle arrest methods were used to understand the apoptotic mechanism of action. The intracellular ROS method was used to determine the primary mechanism that leads to cytotoxic and genotoxic activity. The Fe-Ni ANPs showed cytotoxic activity with the XTT and clonogenic methods: they had genotoxic potential, as demonstrated via genotoxicity methods. It was determined that the cytotoxic effect was realized by the caspase-dependent apoptotic pathway, and the cells were stopped at the G0/G1 stage by Fe-Ni ANPs. Increased intracellular ROS due to Fe-Ni ANPs led to cytotoxic, genotoxic, and apoptotic activity. Potential risks to human health due to Fe-Ni ANPs were then demonstrated at the cellular level.

Biocompatibility and colorectal anti-cancer activity study of nanosized BaTiO3 coated spinel ferrites

In the present work, different nanoparticles spinel ferrite series (MFe2O4, Co0.5M0.5Fe2O4; M = Co, Mn, Ni, Mg, Cu, or Zn) have been obtained via sonochemical approach. Then, sol-gel method was employed to design core-shell magnetoelectric nanocomposites by coating these nanoparticles with BaTiO3 (BTO). The structure and morphology of the prepared samples were examined by X-ray powder diffraction (XRD), scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscope (HR-TEM), and zeta potential. XRD analysis showed the presence of spinel ferrite and BTO phases without any trace of a secondary phase. Both phases crystallized in the cubic structure. SEM micrographs illustrated an agglomeration of spherical grains with nonuniformly diphase orientation and different degrees of agglomeration. Moreover, HR-TEM revealed interplanar d-spacing planes that are in good agreement with those of the spinel ferrite phase and BTO phase. These techniques along with EDX analyses confirmed the successful formation of the desired nanocomposites. Zeta potential was also investigated. The biological influence of (MFe2O4, CoMFe) MNPs and core-shell (MFe2O4@BTO, CoMFe@BTO) magnetoelectric nanocomposites were examined by MTT and DAPI assays. Post 48 h of treatments, the anticancer activity of MNPs and MENCs was investigated on human colorectal carcinoma cells (HCT-116) against the cytocompatibility of normal non-cancerous cells (HEK-293). It was established that MNPs possess anti-colon cancer capability while MENCs exhibited a recovery effect due to the presence of a protective biocompatible BTO layer. RBCs hemolytic effect of NPs has ranged from non- to low-hemolytic effect. This effect that could be attributed to the surface charge from zeta potential, also the CoMnFe possesses the stable and lowest zeta potential in comparison with CoFe2O4 and MnFe2O4 also to the protective effect of shell. These findings open up wide prospects for biomedical applications of MNPs as anticancer and MENCs as promising drug nanocarriers.

Ferroptosis as a mechanism of non-ferrous metal toxicity

Ferroptosis is a recently discovered form of regulated cell death, implicated in multiple pathologies. Given that the toxicity elicited by some metals is linked to alterations in iron metabolism and induction of oxidative stress and lipid peroxidation, ferroptosis might be involved in such toxicity. Although direct evidence is insufficient, certain pioneering studies have demonstrated a crosstalk between metal toxicity and ferroptosis. Specifically, the mechanisms underlying metal-induced ferroptosis include induction of ferritinophagy, increased DMT-1 and TfR cellular iron uptake, mitochondrial dysfunction and mitochondrial reactive oxygen species (mitoROS) generation, inhibition of Xc-system and glutathione peroxidase 4 (GPX4) activity, altogether resulting in oxidative stress and lipid peroxidation. In addition, there is direct evidence of the role of ferroptosis in the toxicity of arsenic, cadmium, zinc, manganese, copper, and aluminum exposure. In contrast, findings on the impact of cobalt and nickel on ferroptosis are scant and nearly lacking altogether for mercury and especially lead. Other gaps in the field include limited studies on the role of metal speciation in ferroptosis and the critical cellular targets. Although further detailed studies are required, it seems reasonable to propose even at this early stage that ferroptosis may play a significant role in metal toxicity, and its modulation may be considered as a potential therapeutic tool for the amelioration of metal toxicity.

Explorations of tire and road wear microplastics in road dust PM2.5 at eight megacities in China

Tire and road wear microplastics (TRWMPs) in road dust are a key source of atmospheric particulate matter and have an adverse impact on human health and the environment. In this study, samples of particulate matter with a diameter of 2.5 μm or less (PM_2.5) in road dust were collected from eight megacities in China to determine the TRWMP content, including that of natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). The total abundance of TRWMPs was the highest in Lanzhou (174.7 ± 17.0 μg g^-1), followed by Xi'an (169.3 ± 23.8 μg g^-1), Beijing (107.5 ± 7.5 μg g^-1), Changchun (102.2 ± 8.4 μg g^-1), Chengdu (101.6 ± 12.9 μg g^-1), Guangzhou (98.8 ± 6.5 μg g^-1), Wuhan (96.0 ± 5.3 μg g^-1), and Shanghai (86.1 ± 30.1 μg g^-1). A considerably higher TRWMP fraction in road dust PM_2.5 was observed in the northern cities than in the southern cities and is attributable to the higher frictional resistance of roads subjected to less precipitation. The abundance of TRWMPs in the southern cities was dependent on road type, but this dependence was not observed in the northern cities. In the south, road dust PM_2.5 on main roads contained more TRWMPs than that on branch roads. Correlation analysis indicated that TRWMPs were associated with tire, road, and break wear. In relation to intracellular oxidative stress factors, higher correlations were observed between TRWMPs and lactate dehydrogenase (r = 0.83) than between TRWMPs and reactive oxygen species (r = 0.59), possibly because TRWMPs destroy the integrity of the cell membrane, with NR exhibiting a higher cytotoxicity than SBR or BR. This study provides evidence that TRWMPs have an adverse impact on human health by inducing cellular oxidative stress. Therefore, further research on TRWMPs in respirable road dust is required.

NiONPs-induced alteration in calcium signaling and mitochondrial function in pulmonary artery endothelial cells involves oxidative stress and TRPV4 channels disruption

In New Caledonia, anthropic activities, such as mining, increase the natural erosion of soils in nickel mines, which in turn, releases nickel oxide nanoparticles (NiONPs) into the atmosphere. Pulmonary vascular endothelial cells represent one of the primary targets for inhaled nanoparticles. The objective of this in vitro study was to assess the cytotoxic effects of NiONPs on human pulmonary artery endothelial cells (HPAEC). Special attention will be given to the level of oxidative stress and calcium signaling, which are involved in the physiopathology of cardiovascular diseases. HPAEC were exposed to NiONPs (0.5-150 μg/cm²) for 4 or 24 h. The following different endpoints were studied: (i) ROS production using CM-H₂DCF-DA probe, electron spin resonance, and MitoSOX probe; the SOD activity was also measured (ii) calcium signaling with Fluo4-AM, Rhod-2, and Fluo4-FF probes; (iii) inflammation by IL-6 production and secretion and, (iv) mitochondrial dysfunction and apoptosis with TMRM and MitoTracker probes, and AnnexinV/PI. Our results have evidenced that NiONPs induced oxidative stress in HPAEC. This was demonstrated by an increase in ROS production and a decrease in SOD activity, the two mechanisms seem to trigger a pro-inflammatory response with IL-6 secretion. In addition, NiONPs exposure altered calcium homeostasis inducing an increased cytosolic calcium concentration ([Ca²⁺]_i) that was significantly reduced by the extracellular calcium chelator EGTA and the TRPV4 inhibitor HC-067047. Interestingly, exposure to NiONPs also altered TRPV4 activity. Finally, HPAEC exposure to NiONPs increased intracellular levels of both ROS and calcium ([Ca²⁺]_m) in mitochondria, leading to mitochondrial dysfunction and HPAEC apoptosis.

Nickel nanoparticles induce hepatotoxicity via oxidative and nitrative stress-mediated apoptosis and inflammation

Nickel nanoparticles (Ni NPs) are utilized extensively in various industrial applications. However, there are increasing concerns about potential exposure to Ni NPs and consequent health effects. The aim of this study was to assess Ni NPs-induced liver toxicity in Sprague Dawley rats. Twenty-five rats were exposed to Ni NPs via intraperitoneal injection at doses of 15, 30, and 45 mg/kg per body weight for 28 days. Results from ICP-MS analysis showed an increase in the concentration of Ni NPs in a dose-dependent manner. The liver dysfunction was indicated by considerable production of ALT, AST, ALP, LDH, and TB in Ni NPs-treated rats. Histological examination demonstrated liver injuries (inflammatory cells, congestion, necrosis, and pyknosis) in exposed rats with dose-dependent severity of pathologies by semi-quantitative histograding system. To explore the toxicological pathways, we examined oxidative stress biomarkers and detected Ni NPs significantly elevated the levels of MDA and LPO while decreasing the levels of CAT and GSH. All the changes in biomarkers were recorded in a dose-dependent relationship. In addition, we found upregulated NF-kβ indicating activation of inflammatory cytokines. ELISA results of serum revealed a remarkable increase of nitrative stress markers (iNOS and NO), ATPase activity, inflammatory cytokine (IL-6, IL-1β, and TNF-α), and apoptotic mediators (caspase-3 and caspase-9) in Ni NPs-treated groups than the control. In summary, the result of this study provided evidence of hepatotoxicity of Ni NPs and insightful information about the involved toxic pathways, which will help in health risk assessment and management, related preventive measures for the use of Ni-NPs materials.

Biochemical and histological alterations induced by nickel oxide nanoparticles in the ground beetle Blaps polychresta (Forskl, 1775) (Coleoptera: Tenebrionidae)

The present study evaluates the effect of nickel oxide nanoparticles on some biochemical parameters and midgut tissues in the ground beetle Blaps polychresta as an indicator organism for nanotoxicity. Serial doses of the NiO-NPs colloid (0.01, 0.02, 0.03, 0.04, 0.05, and 0.06 mg/g) were prepared for injecting into the adult beetles. Insect survival was reported daily for 30 days, and the sublethal dose of 0.02 mg/g NiO-NPs was selected for the tested parameters. After the treatment, nickel was detected in the midgut tissues by X-ray microanalysis. The treated group demonstrated a significant increase in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities when compared to the untreated group. However, the treated group demonstrated a significant decrease in ascorbate peroxidase (APOX) activity when compared to the untreated group. Histological and ultrastructural changes in the midgut tissues of treated and untreated beetles were also observed. The current findings provide a precedent for describing the physiological and histological changes caused by NiO-NPs in the ground beetle B. polychresta.

Toxicity assessment of metallic nickel nanoparticles in various biological models: An interplay of reactive oxygen species, oxidative stress, and apoptosis

Nickel nanoparticles (Ni-NPs) are widely used for multiple purposes in industries. Ni-NPs exposure is detrimental to ecosystems owing to widespread use, and so their toxicity is important to consider for real-world applications. This review mainly focuses on the notable pathophysiological activities of Ni-NPs in various research models. Ni-NPs are stated to be more toxic than bulk forms because of their larger surface area to volume ratio and are reported to provoke toxicity through reactive oxygen species generation, which leads to the upregulation of nuclear factor-κB and promotes further signaling cascades. Ni-NPs may contribute to provoking oxidative stress and apoptosis. Hypoxia-inducible factor 1α and mitogen-activated protein kinases pathways are involved in Ni-NPs associated toxicity. Ni-NPs trigger the transcription factors p-p38, p-JNK, p-ERK1/2, interleukin (IL)-3, TNF-α, IL-13, Fas, Cyt c, Bax, Bid protein, caspase-3, caspase-8, and caspase-9. Moreover, Ni-NPs have an occupational vulnerability and were reported to induce lung-related disorders owing to inhalation. Ni-NPs may cause serious effects on reproduction as Ni-NPs induced deleterious effects on reproductive cells (sperm and eggs) in animal models and provoked hormonal alteration. However, recent studies have provided limited knowledge regarding the important checkpoints of signaling pathways and less focused on the toxic limitation of Ni-NPs in humans, which therefore needs to be further investigated.

Oxidative stress-inducing effects of various urban PM2.5 road dust on human lung epithelial cells among 10 Chinese megacities

PM2.5 Road dust samples were collected from 10 representative cities in southern and northern China for examination of chemical components and oxidative stress levels in A549 cells. Downtown road dust was abundance of heavy metals, EC and PAHs compared to nondowntown road dust. Source apportionment also revealed the relative higher contribution of vehicle emission to downtown (35.8%) than nondowntown road dust (25.5%). Consequently, downtown road dust induced much higher intracellular reactive oxidative species (ROS) levels than that from nondowntown (p < 0.05). This study highlights that the ROS-inducing capacity of road dust in China is lower at lower latitudes, which resulted in a significantly higher ROS-inducing capacity of road dust from northern cities than southern ones. Hotspot analysis demonstrated that heavy metals (i.e., Cr, Zn, Cu and Pb) in road dust were the most closely associated with ROS production in A549 cells. Vehicle emission and combustion emission in road dust were identified to be correlated with cellular ROS production. The findings highlight the ROS-inducing effect of PM2.5 road dust and also serve as a reference to make the targeted solutions for urban road dust pollution control, especially from a public health perspective.

Mechanisms of Nickel-Induced Cell Damage in Allergic Contact Dermatitis and Nutritional Intervention Strategies

BACKGROUND

Hypersensitivity to nickel is a very common cause of allergic contact dermatitis since this metal is largely present in industrial and consumer products as well as in some commonly consumed foods, air, soil, and water. In nickel-sensitized individuals, a cell-mediated delayed hypersensitivity response results in contact to dermatitis due to mucous membranes coming in long-term contact with nickel-containing objects. This process involves the generation of reactive oxidative species and lipid peroxidation-induced oxidative damage. Immunologically, the involvement of T helper (h)-1 and Th-2 cells, as well as the reduced function of T regulatory cells, are of importance. The toxicity, mutagenicity, and carcinogenicity of nickel are attributed to the generation of reactive oxygen species and induction of oxidative damage via lipid peroxidation, which results in DNA damage.

OBJECTIVE

The aim of this research is to identify nutritionally actionable interventions that can intercept nickel-induced cell damage due to their antioxidant capacities.

CONCLUSION

Nutritional interventions may be used to modulate immune dysregulation, thereby intercepting nickel-induced cellular damage. Among these nutritional interventions are a low-nickel diet and an antioxidant-rich diet that is sufficient in iron needed to minimize nickel absorption. These dietary approaches not only reduce the likelihood of nickel toxicity by minimizing nickel exposure but also help prevent oxidative damage by supplying the body with antioxidants that neutralize free radicals.

Cytotoxic, Genotoxic, and Apoptotic Effects of Nickel Oxide Nanoparticles in Intestinal Epithelial Cells

Objectives

The superior properties of nickel oxide-nanoparticles (NiO-NPs) have led to their wide use in various fields. However, there is little comprehensive knowledge about their toxicity, especially after oral exposure. The toxic effect of NiO-NPs of mean size 15.0 nm was investigated in Caco-2 (human intestinal epithelial) cells as no study has been performed on their intestinal toxicity.

Materials and Methods

Following identification of their particle size distribution and cellular uptake potential, the risk of exposure to NiO-NPs was evaluated by cellular morphologic changes, cyto- and genotoxic potentials, oxidative damage, and apoptotic induction.

Results

NiO-NPs induced a 50% reduction in cell viability at 351.6 μg/mL and caused DNA damage and oxidative damage at 30-150 μg/mL. It appears that apoptosis might be a main cell death mechanism in NiO-NP-exposed intestinal cells.

Conclusion

NiO-NPs might be hazardous to the gastrointestinal system. The results should raise concerns about using NiO-NPs in food-contact appliances and about NiO-NP-containing wastes. Further in vivo and in vitro research should be conducted to explain the specific toxicity mechanism of these particles and reduce their risk to humans.

Tailoring Iron Oxide Nanoparticles for Efficient Cellular Internalization and Endosomal Escape

Iron oxide nanoparticles (IONs) have been widely explored for biomedical applications due to their high biocompatibility, surface-coating versatility, and superparamagnetic properties. Upon exposure to an external magnetic field, IONs can be precisely directed to a region of interest and serve as exceptional delivery vehicles and cellular markers. However, the design of nanocarriers that achieve an efficient endocytic uptake, escape lysosomal degradation, and perform precise intracellular functions is still a challenge for their application in translational medicine. This review highlights several aspects that mediate the activation of the endosomal pathways, as well as the different properties that govern endosomal escape and nuclear transfection of magnetic IONs. In particular, we review a variety of ION surface modification alternatives that have emerged for facilitating their endocytic uptake and their timely escape from endosomes, with special emphasis on how these can be manipulated for the rational design of cell-penetrating vehicles. Moreover, additional modifications for enhancing nuclear transfection are also included in the design of therapeutic vehicles that must overcome this barrier. Understanding these mechanisms opens new perspectives in the strategic development of vehicles for cell tracking, cell imaging and the targeted intracellular delivery of drugs and gene therapy sequences and vectors.

Pathogenic Mechanisms and Therapeutic Implication in Nickel-Induced Cell Damage

Background:

Nickel (Ni) is mostly applied in a number of industrial areas such as printing inks, welding, alloys, electronics and electrical professions. Occupational or environmental exposure to nickel may lead to cancer, allergy reaction, nephrotoxicity, hepatotoxicity, neurotoxicity, as well as cell damage, apoptosis and oxidative stress.

Methods:

In here, we focused on published studies about cell death, carcinogenicity, allergy reactions and neurotoxicity, and promising agents for the prevention and treatment of the toxicity by Ni.

Results:

Our review showed that in the last few years, more researches have focused on reactive oxygen species formation, oxidative stress, DNA damages, apoptosis, interaction with involving receptors in allergy and mitochondrial damages in neuron induced by Ni.

Conclusion:

The collected data in this paper provide useful information about the main toxicities induced by Ni, also, their fundamental mechanisms, and how to discover new ameliorative agents for prevention and treatment by reviewing agents with protective and therapeutic consequences on Ni induced toxicity.

Effect and mechanism of PI3K/AKT/mTOR signaling pathway in the apoptosis of GC-1 cells induced by nickel nanoparticles

Nickel nanoparticles (Ni NPs) have a wide range of application prospects, but there is still a lack of their safety evaluation for the reproductive system. Nowadays, male reproductive health has been widely concerned because of the increasing incidence of male infertility. Studies have shown that Ni NPs can cause male reproductive toxicity. The purpose of this study was to investigate the toxicity of Ni NPs on GC-1 cells, a mouse spermatogonia cell line, and to explore the possible mechanism underlying the induction of apoptosis via PI3K/AKT/mTOR signaling pathway. The cell ultrastructure was firstly observed under a transmission electron microscope. Then, cell proliferation, cycle and apoptosis were detected by CCK-8 and flow cytometry, respectively. Furthermore, the expression levels of related proteins and genes were determined by Western blot and Reverse transcription-polymerase chain reaction, respectively. The results showed that Ni NPs could not only cause changes in cell ultrastructure, decreased survival rate and arrested G1 phase cell cycle, but also activated apoptosis pathway by inhibiting the PI3K/AKT/mTOR signaling pathway. The results of this study provide novel insights to explore the mechanisms of reproductive toxicity of Ni NPs and are of great significance to develop safety evaluation criteria for Ni NPs.

Advance on toxicity of metal nickel nanoparticles

As a kind of conventional metal nanomaterial, nickel nanoparticles (Ni NPs) have broad application prospects in the fields of magnetism, energy technology and biomedicine and have quickly attracted great interest. The potential negative effects of Ni NPs have also attracted wide attention from some researchers. Studies have shown that Ni NPs cause a variety of toxic effects on cells, animals and humans and have toxic effects of multiple systems such as respiratory system, cardiovascular system and reproductive system. Ni NPs can lead to oxidative stress, apoptosis, DNA damage and inflammation and induce the increase of intracellular reactive oxygen species. The toxicity of Ni NPs is also found to be related to the mitogen-activated protein kinase pathway and the hypoxia inducible factor-1α pathway. Therefore, the toxicity and mechanism of Ni NPs are reviewed in this paper, and the future researches in this field are also proposed.

Biocompatible Magnetic Micro- and Nanodevices: Fabrication of FePt Nanopropellers and Cell Transfection

The application of nanoparticles for drug or gene delivery promises benefits in the form of single-cell-specific therapeutic and diagnostic capabilities. Many methods of cell transfection rely on unspecific means to increase the transport of genetic material into cells. Targeted transport is in principle possible with magnetically propelled micromotors, which allow responsive nanoscale actuation and delivery. However, many commonly used magnetic materials (e.g., Ni and Co) are not biocompatible, possess weak magnetic remanence (Fe₃ O₄ ), or cannot be implemented in nanofabrication schemes (NdFeB). Here, it is demonstrated that co-depositing iron (Fe) and platinum (Pt) followed by one single annealing step, without the need for solution processing, yields ferromagnetic FePt nanomotors that are noncytotoxic, biocompatible, and possess a remanence and magnetization that rival those of permanent NdFeB micromagnets. Active cell targeting and magnetic transfection of lung carcinoma cells are demonstrated using gradient-free rotating millitesla fields to drive the FePt nanopropellers. The carcinoma cells express enhanced green fluorescent protein after internalization and cell viability is unaffected by the presence of the FePt nanopropellers. The results establish FePt, prepared in the L1₀ phase, as a promising magnetic material for biomedical applications with superior magnetic performance, especially for micro- and nanodevices.

A comparative study of nickel nanoparticle and ionic nickel toxicities in zebrafish: histopathological changes and oxidative stress

Industry demand for nanomaterials is growing, but metal nanoparticle toxicity is not fully understood. For example, nickel nanoparticles (NiNPs) are used in electric capacitors, and their consumption is increasing, but there have been few reports of their toxicity and environmental effects. To elucidate the toxicological characteristics of NiNPs, we investigated their effects on the histopathology and oxidative states of zebrafish (Danio rerio) and compared the results with those of ionic nickel. Zebrafish exposed to four different concentrations of NiNPs or NiCl₂ for 72 hr or 7 days were subjected to histopathological analysis, and tissue samples were subjected to analyses for oxidative stress and gene expression. High concentrations of both NiNPs and NiCl₂ caused tissue damage in the gills, digestive tract, and liver. The damage was typically characterized by epithelial degeneration and necrosis in the gills, esophagus, and intestines, as well as by lipid loss and palisade pattern degradation in the liver. The damages to the gills, esophagus, and intestines were more severe after exposure to NiNPs, but exposure to NiCl₂ led to more severe liver damage. Exposure to NiNPs increased lipid peroxidation in the skin but decreased it in the liver and intestines; exposure to NiCl₂ increased lipid peroxidation in the intestines. Only exposure to NiCl₂ changed antioxidative responses, enzymatic antioxidant activities, and metallothionein gene expression. These results indicate that NiNPs, which are highly adsorptive, cause severe damage to the epithelium by physical contact with the cell surface and production of reactive oxygen spices, whereas ionic nickel, which is absorptive, affects cellular antioxidative responses by absorption into the body and delivery to the liver.

Biochemical and behavioral responses of zebrafish embryos to magnetic graphene/nickel nanocomposites

Graphene nanocomposites are emerging carbon-based materials with interesting electrical, mechanical, optical and magnetic properties, relevant for applications in different fields. Despite this increased use, the impact of graphene nanocomposites residues in the environment has not been properly studied. Thus, the goal of this work was to assess the toxicity of two nickel/graphene nanocomposites (G/Ni1 and G/Ni2) differing in size and shape to Danio rerio embryos. Their toxicity was evaluated using apical (mortality, development and hatching), biochemical [cholinesterase (ChE), glutathione-S-transferase (GST), and catalase (CAT) activities] and behavioral (locomotor activity) endpoints. At the tested concentrations, neither of the nanocomposites presented lethal or developmental effects. Nevertheless, both nanocomposites induced behavioral effects, reducing swimming distances. This effect was, however detected at lower concentrations in the G/Ni1 nanocomposite. At biochemical level, only G/Ni1 nanocomposite showed to interfere with the measured parameters, increasing the activities of ChE, CAT and GST. Differences in the effects induced by the two nanocomposites seem to be related not only with their size, but also with the shape and the ability to continuously release nickel ions to aqueous medium. This work highlights the importance of studying graphene nanocomposites effects to aquatic organisms even when acute toxicity is not expected. The relevance of the effects found in this work need to be further analyzed in light of the consequences to the long-term fitness of the organisms and in light of the environmental concentrations expected for this type of compounds.

Protein corona formation and its constitutional changes on magnetic nanoparticles in serum featuring a polydehydroalanine coating: effects of charge and incubation conditions

The inevitable formation of a protein corona upon contact of nanoparticles with different biological fluids is of great interest in the context of biomedical applications. It is well established that the surface chemistry of the respective nanomaterial has tremendous impact on protein adsorption, both in terms of the actual amount as well as the type of proteins adsorbed. In that regard, especially polyzwitterions are discussed as coating materials as they are known to partially inhibit protein adsorption. We herein present comparative incubation studies on iron oxide nanoparticles (either single core (SPION) or multicore nanoparticles (MCNP)) after coating with either polyanionic or polyzwitterionic polymeric shells based on polydehydroalanine (PDha). Apart from varying surface charge and chemistry, also the influence of incubation time and temperature on the formation and composition of a protein corona upon exposure to fetal calf serum was investigated. The amounts of adsorbed biomolecules were determined using thermogravimetric analysis. SDS-PAGE experiments revealed information on protein composition as major components of the biomolecule corona. Our results show that distinctly lower amounts of proteins are adsorbed onto polyzwitterionic hybrid nanoparticles in general, but also the corona composition varies as indicated by elevated relative ratios of medium molecular weight proteins (i.e. proteins 25-100 kDa) estimated by non-specific silver protein staining. In addition, increasing relative amounts of albumin (67 kDa) via specific Western blot assays on PDha-coated MCNP are detected.

Mechanisms underlying nickel nanoparticle induced reproductive toxicity and chemo-protective effects of vitamin C in male rats

The purpose of this research is to go a step further study on the reproductive toxicities and the underlying mechanisms induced by nickel nanoparticles (NiNPs), and the possible protective action of vitamin C. Animal experiment was designed according to the one-generation reproductive toxicity standard, and rats were exposed to NiNPs through gavage. Ultrastructural, reactive oxygen species (ROS), oxidant and antioxidant enzymes, and cell apoptosis-related factors in the testicular tissue were analyzed. In contrast with the control group, the activity of surperoxide dismutase (SOD), catalase (CAT) and gonad-stimulating hormone (GSH) was reduced, while the content of nitric oxide (NO), malondialdehyde (MDA) and ROS was increased in the NiNPs treated animals. As the doses of NiNPs increase, the mRNA of apoptotic related factor Caspase-9, Caspase-8 and Caspase-3 showed an obviously upregulation. Protein expression of Bcl-2-associated X Protein (Bax) and apoptosis inducing factor (AIF) was significantly unregulated. After addition of antioxidants-vitamin C, the toxicity was reduced. Injured testicular tissue indicated that NiNPs exposure could damage the reproductive system. Our results suggest that NiNPs induce significant reproductive toxicities. The cellular apoptosis might be induced by caspase family proteinases, but the regulator factor (factor associated suicide (Fas), B-cell lymphoma-2 (Bcl-2), Bax, BH3-interacting domain death agonist (Bid) and AIF protein) might not be involved in this process. Thus, the mechanism of reproductive toxicity of NiNPs on rat testes involves in the induction of oxidative stress, which further results in cell apoptosis. Antioxidants-vitamin C shows a significant inhibition on the reproductive toxicities induced by NiNPs.

High-throughput transcriptomics: Insights into the pathways involved in (nano) nickel toxicity in a key invertebrate test species

Nickel nanoparticles (NiNPs) have an estimated production of ca. 20 tons per year in the US. Nickel has been risk-assessed for long in Europe, but not NiNPs, hence the concern for the environment. In the present study, we focused on investigating the mechanisms of toxicity of NiNPs and the comparison to NiNO₃. The high-throughput microarray for the soil ecotox model Enchytraeus crypticus (Oligochaeta) was used. To anchor gene to phenotype effect level, organisms were exposed to reproduction effect concentrations EC20 and EC50, for 3 and 7 days. Results showed commonly affected pathways between NiNPs and NiNO₃, including increase in proteolysis, apoptosis and inflammatory response, and interference with the nervous system. Mechanisms unique to NiNO₃ were also observed (e.g. glutathione synthesis). No specific mechanisms for NiNPs were found, which could indicate that longer exposure period (>7 days) is required to capture the peak response to NiNPs. A mechanisms scheme is assembled, showing both common and unique mechanisms to NiNO₃ and NiNPs, providing an important framework for further, more targeted, studies.

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

High-performance bioceramics are required for preventing failure and prolonging the life-time of bone grafting scaffolds and osseous implants. The proper identification and development of materials with extended functionalities addressing socio-economic needs and health problems constitute important and critical steps at the heart of clinical research. Recent findings in the realm of ion-substituted hydroxyapatite (HA) could pave the road towards significant developments in biomedicine, with an emphasis on a new generation of orthopaedic and dentistry applications, since such bioceramics are able to mimic the structural, compositional and mechanical properties of the bone mineral phase. In fact, the fascinating ability of the HA crystalline lattice to allow for the substitution of calcium ions with a plethora of cationic species has been widely explored in the recent period, with consequent modifications of its physical and chemical features, as well as its functional mechanical and in vitro and in vivo biological performance. A comprehensive inventory of the progresses achieved so far is both opportune and of paramount importance, in order to not only gather and summarize information, but to also allow fellow researchers to compare with ease and filter the best solutions for the cation substitution of HA-based materials and enable the development of multi-functional biomedical designs. The review surveys preparation and synthesis methods, pinpoints all the explored cation dopants, and discloses the full application range of substituted HA. Special attention is dedicated to the antimicrobial efficiency spectrum and cytotoxic trade-off concentration values for various cell lines, highlighting new prophylactic routes for the prevention of implant failure. Importantly, the current in vitro biological tests (widely employed to unveil the biological performance of HA-based materials), and their ability to mimic the in vivo biological interactions, are also critically assessed. Future perspectives are discussed, and a series of recommendations are underlined.

Nickel Oxide (NiO) Nanoparticles Induce Loss of Cell Viability in Yeast Mediated by Oxidative Stress

The present work aimed to elucidate whether the toxic effects of nickel oxide (NiO) nanoparticles (NPs) on the yeast Saccharomyces cerevisiae were associated with oxidative stress (OS) and what mechanisms may have contributed to this OS. Cells exposed to NiO NPs accumulated superoxide anions and hydrogen peroxide, which were intracellularly generated. Yeast cells coexposed to NiO NPs and antioxidants (l-ascorbic acid and N- tert-butyl-α-phenylnitrone) showed quenching of reactive oxygen species (ROS) and increased resistance to NiO NPs, indicating that the loss of cell viability was associated with ROS accumulation. Mutants lacking mitochondrial DNA (ρ⁰) displayed reduced levels of ROS and increased resistance to NiO NPs, which suggested the involvement of the mitochondrial respiratory chain in ROS production. Yeast cells exposed to NiO NPs presented decreased levels of reduced glutathione (GSH). Mutants deficient in GSH1 ( gsh1Δ) or GSH2 ( gsh2Δ) genes displayed increased levels of ROS and increased sensitivity to NiO NPs, which underline the central role of GSH against NiO NPs-induced OS. This work suggests that the increased levels of intracellular ROS (probably due to the perturbation of the electron transfer chain in mitochondria) combined with the depletion of GSH pool constitute important mechanisms of NiO NPs-induced loss of cell viability in the yeast S. cerevisiae.

Genotoxicity of Copper and Nickel Nanoparticles in Somatic Cells of Drosophila melanogaster

Copper and nickel nanoparticles (Cu-NPs and Ni-NPs, respectively) are used in a variety of industrial applications, such as semiconductors, catalysts, sensors, and antimicrobial agents. Although studies on its potential genotoxicity already exist, few of them report in vivo data. In the present study we have used the wing-spot assay in Drosophila melanogaster to determine the genotoxic activity of Cu-NPs and Ni-NPs, and these data have been compared with those obtained with their microparticle forms (MPs). Additionally, a complete physical characterization of NPs using transmission electronic microscopy (TEM), dynamic light scattering (DLS), and laser Doppler velocimetry (LDV) techniques was also performed. Results obtained with Cu-NPs and Cu-MPs indicate that both failed to induce an increase in the frequency of mutant spots formation in the wings of the adults, suggesting a lack of genotoxicity in somatic cells of D. melanogaster. However, when Ni-NPs and Ni-MPs were evaluated, a significant increase of small single spots and total mutant spots was observed only for Ni-NPs (P<0.05) at the highest dose assessed. Thus, the genotoxicity of Ni-NPs seem to be related to their nanoscale size, because no genotoxic effects have been reported with their microparticles and ions. This study is the first assessing the in vivo genotoxic potential of Cu-NPs and Ni-NPs in the Drosophila model.

Genotoxicity study of nickel oxide nanoparticles in female Wistar rats after acute oral exposure

Nanoparticles (NPs) apart from their widespread advantages and increased utilisation, have aroused concerns over their safe use. Nickel (II) oxides (NiO) NPs are used as catalysts, biosensors and in many of the consumer products. The increasing use of NiO NPs necessitates an improved understanding of their potential impact on the environment and human health. In this study, we investigated the acute genotoxic effects of NiO NPs by oral route administration with three different doses (125, 250 and 500 mg/kg bw). Before the in vivo toxicological evaluation, characterisation of particles by Transmission Electron Microscopy, X-ray diffraction, Dynamic Light Scattering (DLS) and Laser Doppler Velocimetry analysis was performed. Genotoxicity biomarkers such as comet, micronucleus and chromosomal aberrations (CAs) assays were utilised in this study. To document the uptake, retention and elimination of the NPs, biodistribution studies were also performed. The particle size obtained from Transmission Electron Microscopy analysis for NiO NPs was 15.62 ± 2.59 nm. The mean hydrodynamic diameter and PdI of NiO NPs in Milli-Q water suspension obtained by DLS was 168.9 ± 17.13 nm and 0.375, respectively. Comet assay revealed significant (P < 0.001) DNA damage at 500 mg/kg bw dose in the PBL, liver and kidney cells of rats at the 24-h sampling time. The result of micronucleus and CAs tests was in agreement with the comet assay data. Biodistribution of NiO NPs revealed a maximum accumulation of Ni in the liver tissue at the 24-h sampling time. Our study showed significant DNA damage at the high dose level and the effect was more prominent at 24-h sampling time, providing preliminary evidence that the NiO NPs are capable of inducing genotoxicity when administered through the oral route. However, mechanistic investigations are needed before drawing any firm conclusion regarding the toxicology of NiO NPs.

NiO nanoparticles induce cytotoxicity mediated through ROS generation and impairing the antioxidant defense in the human lung epithelial cells (A549): Preventive effect of Pistacia lentiscus essential oil

Nickel oxide nanoparticles (NiO NPs) have attracted increasing attention owing to potential capacity to penetrate to several human cell systems and exert a toxic effect. Elsewhere, the use of medicinal plants today is the form of the most widespread medicine worldwide. Utilizing aromatic plants as interesting source of phytochemicals constitute one of the largest scientific concerns. Thus this study was focused to investigate antioxidant and cytoprotective effects of essential oil of a Mediterranean plant P. lentiscus (PLEO) on NiO NPs induced cytotoxicity and oxidative stress in human lung epithelial cells (A549). The obtained results showed that cell viability was reduced by NiO NPs, who's also found to induce oxidative stress in dose-dependent manner indicated by induction of reactive oxygen species and reduction of antioxidant enzymes activities. Our results also demonstrated that PLEO contains high amounts in terpinen-4-ol (11.49%), germacrene D (8.64%), α-pinene (5.97%), sabinene (5.19%), caryophyllene (5.10%) and δ-Cadinene (4.86%). PLEO exhibited a potent antioxidant capacity by cell viability improving, ROS scavenging and enhancing the endogenous antioxidant system against NiO NPs in this model of cells. The present work demonstrated, for the first time, the protective activity of PLEO against cell oxidative damage induced by NiO NPs. It was suggested that this plant essential oil could be use as a cells protector.

Nickel chloride-induced apoptosis via mitochondria- and Fas-mediated caspase-dependent pathways in broiler chickens

Ni, a metal with industrial and commercial uses, poses a serious hazard to human and animal health. In the present study, we used flow cytometry, immunohistochemistry and qRT-PCR to investigate the mechanisms of NiCl₂-induced apoptosis in kidney cells. After treating 280 broiler chickens with 0, 300, 600 or 900 mg/kg NiCl₂ for 42 days, we found that two caspase-dependent pathways were involved in the induced renal tubular cell apoptosis. In the mitochondria-mediated caspase-dependent apoptotic pathway, cyt-c, HtrA2/Omi, Smac/Diablo, apaf-1, PARP, and caspase-9, 3, 6 and 7 were all increased, while. XIAP transcription was decreased. Concurrently, in the Fas-mediated caspase-dependent apoptotic pathway, Fas, FasL, caspase-8, caspase-10 and Bid levels were all increased. These results indicate that dietary NiCl₂ at 300+ mg/kg induces renal tubular cell apoptosis in broiler chickens, involving both mitochondrial and Fas-mediated caspase-dependent apoptotic pathways. Our results provide novel insight into Ni and Ni-compound toxicology evaluated in vitro and in vivo.

Synthetic Nanoparticles That Promote Tumor Necrosis Factor Receptor 2 Expressing Regulatory T Cells in the Lung and Resistance to Allergic Airways Inflammation

Synthetic glycine coated 50 nm polystyrene nanoparticles (NP) (PS50G), unlike ambient NP, do not promote pulmonary inflammation, but instead, render lungs resistant to the development of allergic airway inflammation. In this study, we show that PS50G modulate the frequency and phenotype of regulatory T cells (Treg) in the lung, specifically increasing the proportion of tumor necrosis factor 2 (TNFR2) expressing Treg. Mice pre-exposed to PS50G, which were sensitized and then challenged with an allergen a month later, preferentially expanded TNFR2⁺Foxp3⁺ Treg, which further expressed enhanced levels of latency associated peptide and cytotoxic T-lymphocyte associated molecule-4. Moreover, PS50G-induced CD103⁺ dendritic cell activation in the lung was associated with the proliferative expansion of TNFR2⁺Foxp3⁺ Treg. These findings provide the first evidence that engineered NP can promote the selective expansion of maximally suppressing TNFR2⁺Foxp3⁺ Treg and further suggest a novel mechanism by which NP may promote healthy lung homeostasis.

Graphene oxide induces cytotoxicity and oxidative stress in bluegill sunfish cells

Graphene oxide (GO) is considered a promising material for biological application due to its unique properties. However, the potential toxicity of GO to aquatic organism particularly bluegill sun fish cells (BF-2) is unexplored or remains poorly understood. GO-induced cytotoxicity and oxidative stress in BF-2 cells were assessed using a battery of biomarkers. Two different biological assays (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red uptake were used to evaluate the cytotoxicity of GO on BF-2 cells. It was found that GO induced dose- and time-dependent cytotoxicity on BF-2 cells. BF-2 cells exposed to lower concentration of GO (40 μg ml^-1 ) for 24 induced morphological changes when compared to their respective controls. As evidence for oxidative stress lipid peroxidation, superoxide dismutase, catalase, reactive oxygen species and 8-hydroxy-2'-deoxyguanosine levels were increased and glutathione levels were found to decline in BF-2 cells after treatment with GO. Our findings demonstrate that GO when exposed to BF-2 fish cells cause oxidative stress.

Hazard assessment of nickel nanoparticles in soil-The use of a full life cycle test with Enchytraeus crypticus

Nanoparticles (NPs) such as nickel (Ni) are widely used in several applications. Nevertheless, the environmental effects of Ni NPs are still poorly understood. In the present study, the toxicity of Ni NPs and nickel nitrate (NiNO₃ ) was assessed using the standard test species in soil ecotoxicology, Enchytraeus crypticus (Oligochaeta), in a full life cycle test, adding the endpoints hatching, growth, and time to reach maturity, besides survival and reproduction as in the standard Organisation for Economic Co-operation and Development Guideline 220 and/or International Organization for Standardization 16387. For Ni NPs, the Ni in soil and in soil solution was concentration- and time-dependent, with a relatively higher soil solution content in the lower and shorter exposure concentrations and times. Overall, NiNO₃ was more toxic than Ni NPs, and toxicity seemed to occur via different mechanisms. The former caused reduced hatching (50% effect concentration [EC50] = 39 mg Ni/kg soil), and the negative effects remained throughout the life cycle, in all measured endpoints (growth, maturation, survival, and reproduction). For Ni NPs, hatching was the most sensitive endpoint (EC50 = 870 mg Ni/kg soil), although the organisms recovered; that is, additional endpoints across the life cycle showed that this effect corresponded to a delay in hatching because organisms survived and reproduced at concentrations up to 1800 mg Ni/kg soil. On the other hand, the lowest tested concentration of Ni NPs (100 mg Ni/kg soil) caused reproduction effects similar to those at higher concentrations (1000 and 1800 mg Ni/kg soil). The present results show that the potential implications of a nonmonotonic dose response should be considered when assessing the risks of Ni NP exposure in soil. Environ Toxicol Chem 2017;36:2934-2941. © 2017 SETAC.

Probing the toxicity of nanoparticles: a unified in silico machine learning model based on perturbation theory

Nanoparticles (NPs) are part of our daily life, having a wide range of applications in engineering, physics, chemistry, and biomedicine. However, there are serious concerns regarding the harmful effects that NPs can cause to the different biological systems and their ecosystems. Toxicity testing is an essential step for assessing the potential risks of the NPs, but the experimental assays are often very expensive and usually too slow to flag the number of NPs that may cause adverse effects. In silico models centered on quantitative structure-activity/toxicity relationships (QSAR/QSTR) are alternative tools that have become valuable supports to risk assessment, rationalizing the search for safer NPs. In this work, we develop a unified QSTR-perturbation model based on artificial neural networks, aimed at simultaneously predicting general toxicity profiles of NPs under diverse experimental conditions. The model is derived from 54,371 NP-NP pair cases generated by applying the perturbation theory to a set of 260 unique NPs, and showed an accuracy higher than 97% in both training and validation sets. Physicochemical interpretation of the different descriptors in the model are additionally provided. The QSTR-perturbation model is then employed to predict the toxic effects of several NPs not included in the original dataset. The theoretical results obtained for this independent set are strongly consistent with the experimental evidence found in the literature, suggesting that the present QSTR-perturbation model can be viewed as a promising and reliable computational tool for probing the toxicity of NPs.

Effects of Metal Micro and Nano-Particles on hASCs: An In Vitro Model

As the knowledge about the interferences of nanomaterials on human staminal cells are scarce and contradictory, we undertook a comparative multidisciplinary study based on the size effect of zero-valent iron, cobalt, and nickel microparticles (MPs) and nanoparticles (NPs) using human adipose stem cells (hASCs) as a model, and evaluating cytotoxicity, morphology, cellular uptake, and gene expression. Our results suggested that the medium did not influence the cell sensitivity but, surprisingly, the iron microparticles (FeMPs) resulted in being toxic. These data were supported by modifications in mRNA expression of some genes implicated in the inflammatory response. Microscopic analysis confirmed that NPs, mainly internalized by endocytosis, persist in the vesicles without any apparent cell damage. Conversely, MPs are not internalized, and the effects on hASCs have to be ascribed to the release of ions in the culture medium, or to the reduced oxygen and nutrient exchange efficiency due to the presence of MP agglomerating around the cells. Notwithstanding the results depicting a heterogeneous scene that does not allow drawing a general conclusion, this work reiterates the importance of comparative investigations on MPs, NPs, and corresponding ions, and the need to continue the thorough verification of NP and MP innocuousness to ensure unaffected stem cell physiology and differentiation.

Assessment of genotoxicity and biodistribution of nano- and micron-sized yttrium oxide in rats after acute oral treatment

The increasing use of yttrium oxide (Y₂ O₃ ) nanoparticles (NPs) entails an improved understanding of their potential impact on the environmental and human health. In the present study, the acute oral toxicity of Y₂ O₃ NPs and their microparticles (MPs) was carried out in female albino Wistar rats with 250, 500 and 1000 mg kg^-1 body weight doses. Before the genotoxicity evaluation, characterization of the particles by transmission electron microscopy, dynamic light scattering and laser Doppler velocimetry was performed. The genotoxicity studies were conducted using micronucleus and comet assays. Results showed that Y₂ O₃ NP-induced significant DNA damage at higher dose (1000 mg kg^-1 body weight) in peripheral blood leukocytes and liver cells, micronucleus formation in bone marrow and peripheral blood cells. The findings from biochemical assays depicted significant alterations in aspartate transaminase, alanine transaminase, alkaline phosphatase, malondialdehyde, superoxide dismutase, reduced glutathione, catalase and lactate dehydrogenase levels in serum, liver and kidneys at the higher dose only. Furthermore, tissue biodistribution of both particles was analyzed by inductively coupled plasma optical emission spectrometry. Bioaccumulation of yttrium (Y) in all tissues was significant and dose-, time- and organ-dependent. Moreover, Y₂ O₃ NP-treated rats exhibited higher tissue distribution along with greater clearance through urine whereas Y₂ O₃ MP-dosed animals depicted the maximum amount of Y in the feces. Hence, the results indicated that bioaccumulation of Y₂ O₃ NPs via its Y ions may induce genotoxic effects.

Iron oxide nanoparticles induced cytotoxicity, oxidative stress and DNA damage in lymphocytes

Over the past few decades nanotechnology and material science has progressed extremely rapidly. Iron oxide nanoparticles (IONPs) owing to their unique magnetic properties have a great potential for their biomedical and bioengineering applications. However, there is an inevitable need to address the issue of safety and health effects of these nanoparticles. Hence, the present study was aimed to assess the cytotoxic effects of IONPs on rats' lymphocytes. Using different assays, we studied diverse parameters including mitochondrial membrane potential, intracellular accumulation of reactive oxygen species (ROS), lactate dehydrogenase activity, antioxidant enzymes activity and DNA damage measurements. Intracellular metal uptake and ultrastructure analysis were also carried out through inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy respectively. The results show that the IONP-induced oxidative stress was concentration-dependent in nature, with significant (P < 0.05) increase in ROS levels, lipid peroxidation level as well as depletion of antioxidant enzymes and glutathione. Moreover, we observed morphological changes in the cell after intracellular uptake and localization of nanoparticles in cells. From the findings of the study, it may be concluded that IONPs induce ROS-mediated cytotoxicity in lymphocytes. Copyright © 2017 John Wiley & Sons, Ltd.

Nickel chloride (NiCl2) induces endoplasmic reticulum (ER) stress by activating UPR pathways in the kidney of broiler chickens

It has been known that overexposure to Ni can induce nephrotoxicity. However, the mechanisms of underlying Ni nephrotoxicity are still elusive, and also Ni- and Ni compound-induced ER stress has been not reported in vivo at present. Our aim was to use broiler chickens as animal model to test whether the ER stress was induced and UPR was activated by NiCl2 in the kidney using histopathology, immunohistochemistry and qRT-PCR. Two hundred and eighty one-day-old broiler chickens were divided into 4 groups and fed on a control diet and the same basal diet supplemented with 300 mg/kg, 600mg/kg and 900mg/kg of NiCl2 for 42 days. We found that dietary NiCl2 in excess of 300 mg/kg induced ER stress, which was characterized by increasing protein and mRNA expression of ER stress markers, e.g., GRP78 and GRP94. Concurrently, all the three UPR pathways were activated by dietary NiCl2. Firstly, the PERK pathway was activated by increasing eIF2a and ATF4 mRNA expression. Secondly, the IRE1 pathway was activated duo to increase in IRE1 and XBP1 mRNA expression. And thirdly, the increase of ATF6 mRNA expression suggested that ATF6 pathway was activated. The findings clearly demonstrate that NiCl2 induces the ER stress through activating PERK, IRE1 and ATF6 UPR pathways, which is proved to be a kind of molecular mechanism of Ni- or/and Ni compound-induced nephrotoxicity.

In vitro toxicity assessment of oral nanocarriers

The fascinating properties of nanomaterials opened new frontiers in medicine. Nanocarriers are useful systems in transporting drugs to site-specific targets. The unique physico-chemical characteristics making nanocarriers promising devices to treat diseases may also be responsible for potential adverse effects. In order to develop functional nano-based drug delivery systems, efficacy and safety should be carefully evaluated. To date, no common testing strategy to address nanomaterial toxicological challenges has been generated. Different cell culture models are currently used to evaluate nanocarrier safety using conventional in vitro assays, but overall they have generated a huge amount of conflicting data. In this review we describe state-of-the-art approaches for in vitro testing of orally administered nanocarriers, highlighting the importance of developing harmonized and validated standard operating procedures. These procedures should be applied in a safe-by-design context with the aim to reduce and/or eliminate the uncertainties and risks associated with nanomedicine development.

Spermiotoxicity of nickel nanoparticles in the marine invertebrate Ciona intestinalis (ascidians)

Nickel nanoparticles (Ni NPs) are increasingly used in modern industries as catalysts, sensors, and in electronic applications. Due to this large use, their inputs into marine environment have significantly increased; however, the potential ecotoxicological effects in marine environment have so far received little attention. In particular, little is known on the impact of NPs on gamete quality of marine organisms and on the consequences on fertility potential. The present study examines, for the first time, the impact of Ni NPs exposure on sperm quality of the marine invertebrate Ciona intestinalis (ascidian). Several parameters related with sperm status such as plasma membrane lipid peroxidation, mitochondrial membrane potential (MMP), intracellular pH, DNA integrity, and fertilizing ability were assessed as toxicity end points after exposure to different Ni NPs concentrations. Ni NPs generate oxidative stress that in turn induces lipid peroxidation and DNA fragmentation, and alters MMP and sperm morphology. Furthermore, sperm exposure to Ni NPs affects their fertilizing ability and causes developmental anomalies in the offspring. All together, these results reveal a spermiotoxicity of Ni NPs in ascidians suggesting that the application of these NPs should be carefully assessed as to their potential toxic effects on the health of marine organisms that, in turn, may influence the ecological system. This study shows that ascidian sperm represent a suitable and sensitive tool for the investigation of the toxicity of NPs entered into marine environment, for defining the mechanisms of toxic action and for the environmental monitoring purpose.

Nickel Release, ROS Generation and Toxicity of Ni and NiO Micro- and Nanoparticles

Occupational exposure to airborne nickel is associated with an elevated risk for respiratory tract diseases including lung cancer. Therefore, the increased production of Ni-containing nanoparticles necessitates a thorough assessment of their physical, chemical, as well as toxicological properties. The aim of this study was to investigate and compare the characteristics of nickel metal (Ni) and nickel oxide (NiO) particles with a focus on Ni release, reactive oxygen species (ROS) generation, cellular uptake, cytotoxicity and genotoxicity. Four Ni-containing particles of both nano-size (Ni-n and NiO-n) and micron-size (Ni-m1 and Ni-m2) were tested. The released amount of Ni in solution was notably higher in artificial lysosomal fluid (e.g. 80–100 wt% for metallic Ni) than in cell medium after 24h (ca. 1–3 wt% for all particles). Each of the particles was taken up by the cells within 4 h and they remained in the cells to a high extent after 24 h post-incubation. Thus, the high dissolution in ALF appeared not to reflect the particle dissolution in the cells. Ni-m1 showed the most pronounced effect on cell viability after 48 h (alamar blue assay) whereas all particles showed increased cytotoxicity in the highest doses (20–40 μg cm²) when assessed by colony forming efficiency (CFE). Interestingly an increased CFE, suggesting higher proliferation, was observed for all particles in low doses (0.1 or 1 μg cm^-2). Ni-m1 and NiO-n were the most potent in causing acellular ROS and DNA damage. However, no intracellular ROS was detected for any of the particles. Taken together, micron-sized Ni (Ni-m1) was more reactive and toxic compared to the nano-sized Ni. Furthermore, this study underlines that the low dose effect in terms of increased proliferation observed for all particles should be further investigated in future studies.

Oxidative stress and inflammatory responses involved in dietary nickel chloride (NiCl2)-induced pulmonary toxicity in broiler chickens

The respiratory system is the primary target of nickel or nickel compound toxicity after inhalation exposure. There are no reports on the effects of nickel or nickel compounds on the lung via dietary administration at present. This study aimed to investigate pulmonary toxicity induced by dietary NiCl₂ in broiler chickens by using histopathology, qRT-PCR, and ELISA. In comparison with the control group, NiCl₂ intake induced oxidative damage to DNA (upregulation of 8-OHdG) and lipid peroxidation (upregulation of MDA), which was associated with the upregulation of NO and the downregulation of the expression levels and activities of pulmonary CuZn-SOD, Mn-SOD, CAT, GSH-Px, GR and GST mRNA. Also, the T-AOC activity, GSH content, ability to inhibit the generation of hydroxyl radicals, and ratio of GSH/GSSG were decreased in the groups treated with NiCl₂. Concurrently, the mRNA expression levels of iNOS, TNF-α, COX-2, IL-1β, IL-6, IL-8, IL-18 and IFN-γ were increased via the activation of NF-κB, and the mRNA expression levels of anti-inflammatory mediators including IL-2, IL-4 and IL-13 were decreased in the groups treated with NiCl₂. The above-mentioned results were the first to demonstrate that NiCl₂ intake induced pulmonary oxidative stress and inflammatory responses via the dietary pathway, which subsequently contributed to histopathological lesions and dysfunction.

Nickel-Refining Fumes Induced DNA Damage and Apoptosis of NIH/3T3 Cells via Oxidative Stress

Although there have been numerous studies examining the toxicity and carcinogenicity of nickel compounds in humans and animals, its molecular mechanisms of action are not fully elucidated. In our research, NIH/3T3 cells were exposed to nickel-refining fumes at the concentrations of 0, 6.25, 12.50, 25, 50 and 100 μg/mL for 24 h. Cell viability, cell apoptosis, reactive oxygen species (ROS) level, lactate dehydrogenase (LDH) assay, the level of glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) level were detected. The exposure of NIH/3T3 cells to nickel-refining fumes significantly reduced cell viability and induced cell apoptotic death in a dose-dependent manner. Nickel-refining fumes significantly increased ROS levels and induced DNA damage. Nickel-refining fumes may induce the changes in the state of ROS, which may eventually initiate oxidative stress, DNA damage and apoptosis of NIH/3T3 cells.

Nickel Chloride (NiCl2) Induces Histopathological Lesions via Oxidative Damage in the Broiler's Bursa of Fabricius

The purpose of this study was to investigate the histopathological lesions, oxidative damage, changes of immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) contents in the bursa of Fabricius and serum immunoglobulins (IgG, IgM, IgA) induced by dietary nickel chloride (NiCl2). Two hundred and eighty-one-day-old broilers were randomly divided into four groups and fed on a control diet and three experimental diets supplemented with 300, 600, and 900 mg/kg of NiCl2 for 42 days. Lesions were observed in the NiCl2-treated groups. Histopathologically, lymphocytes were decreased in lymphoid follicles with thinner cortices and wider medullae. Concurrently, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and the ability to inhibit hydroxyl radical and glutathione (GSH) contents were significantly (p < 0.05 or p < 0.01) decreased, while malondialdehyde (MDA) contents were increased in the NiCl2-treated groups. The serum IgG, IgM, and bursa IgG and IgM contents were significantly (p < 0.05 or p < 0.01) lower in the NiCl2-treated groups than those in the control group. The above-mentioned results show that dietary NiCl2 in excess of 300 mg/kg can cause histopathological lesions via oxidative damage, which finally impairs the function of the bursa of Fabricius and reduces IgG and IgM contents of the serum and the bursa of Fabricius. The study is aimed to provide helpful materials for studies on Ni- or Ni compounds-induced B cell toxicity in both human and other animals in the future.