Toxicological assessment of nano and micron-sized tungsten oxide after 28 days repeated oral administration to Wistar rats

Behavior and fate of ITER-like tungsten nanoparticles in freshwater ecosystems produced during operation and maintenance

Within the ITER project (International Thermonuclear Experimental Reactor) an international project building a magnetic confinement device to achieve fusion as a sustainable energy source, tungsten (W) is planned to serve as a plasma-facing component (PFC) in the tokamak, a magnetic confinement device used to produce controlled thermonuclear fusion power. Post plasma-W interactions, submicron tungsten particles can be released. This study investigated the exposure of lentic freshwater ecosystems to ITER-like tungsten nanoparticles in indoor aquatic mesocosms. Monitoring included tungsten (bio)distribution, (bio)transformation, speciation, and impacts following a relevant exposure scenario (chronic, medium-term, low-dose contamination). Additionally, mechanistic studies using a combination of microfluidic cells and X-ray Absorption Spectroscopy (XAS) provided a time-resolved understanding of tungsten's oxidative dissolution in freshwater. Following contamination, tungsten persisted in the water column (over 90 %), showing significant (∼40 %) and rapid (< 7 days) oxidation-dissolution and polymerization. This led to significant exposure of planktonic niches, strong affinity of polymeric tungsten species for aquatic vegetation, and potential transfer to higher trophic levels like aquatic snails. Over five weeks, the bio-physicochemical parameters of the mesocosms remained stable, and no acute impacts were observed on micro- and macro-organisms.

Nanoparticle-Based Interventions for Liver Transplantation

Liver transplantation is the only treatment for hepatic insufficiency as a result of acute and chronic liver injuries/pathologies that fail to recover. Unfortunately, there remains an enormous and growing gap between organ supply and demand. Although recipients on the liver transplantation waitlist have significantly higher mortality, livers are often not allocated because they are (i) classified as extended criteria or marginal livers and (ii) subjected to longer cold preservation time (>6 h) with a direct correlation of poor outcomes with longer cold ischemia. Downregulating the recipient's innate immune response to successfully tolerate a graft having longer cold ischemia times or ischemia-reperfusion injury through induction of immune tolerance in the graft and the host would significantly improve organ utilization and post-transplant outcomes. Broadly, technologies proposed for development aim to extend the life of the transplanted liver through post-transplant or recipient conditioning. In this review, we focus on the potential benefits of nanotechnology to provide unique pre-transplant grafting and recipient conditioning of extended criteria donor livers using immune tolerance induction and hyperthermic pre-conditioning.

Comparative pulmonary toxicity assessment of tungsten trioxide and tungsten trioxide hydrate nanoparticles

Tungsten trioxide (WO₃)-based nanoparticles (NPs) are gaining popularity because of their exciting potential for photocatalytic applications; however, the toxic potential of WO₃-based NPs remains a concern. In this study, we evaluated the toxic risk of WO₃ NPs and hydrated WO₃ NPs (WO₃·H₂O NPs) using lung cells and explored the underlying mechanism. WO₃ NPs and WO₃·H₂O NPs significantly decreased the number of viable cells (59.5 %-85.8 % of control) and promoted apoptosis in human alveolar basal epithelial A549 cells after a 24-h exposure. Both WO₃ NPs and WO₃·H₂O NPs reduced the expression of heme oxygenase-1 (0.15-0.33 folds of control) and superoxide dismutase 2 (0.31-0.66 folds of control) and increased reactive oxygen species production (1.4-2.6 folds of control) and 8-hydroxy-2'-deoxyguanosine accumulation (1.22-1.43 folds of control). The results showed that WO₃ NPs have higher cytotoxicity and oxidative potential than WO₃·H₂O NPs. In addition, the WO₃ NP cellular uptake rate was significantly higher than the WO₃·H₂O NPs uptake rate in pulmonary cells. The greater extent of oxidative adverse effects induced by WO₃-based NPs appears to be related to the enhanced particle uptake. WO₃ NPs and WO₃·H₂O NPs exposure led to the secretion of inflammatory factor interleukin 6 (1.63-3.42 folds of control). Decreases in serpin family A member 1 gene expression (0.28-0.58 folds of control) and increases in the oxidation of neutrophil elastase inhibitor (1.34-1.62 folds of control) in pulmonary cells also suggest that exposure to WO₃ NPs and WO₃·H₂O NPs raises the risk of developing chronic obstructive pulmonary disease. Taken together, our findings indicate that the toxic risk of WO₃ NPs and WO₃·H₂O NPs must be considered when manufacturing and applying WO₃-based NPs.

A systematic quality evaluation and review of nanomaterial genotoxicity studies: a regulatory perspective

The number of publications in the field of nanogenotoxicology and the amount of genotoxicity data on nanomaterials (NMs) in several databases generated by European Union (EU) funded projects have increased during the last decade. In parallel, large research efforts have contributed to both our understanding of key physico-chemical (PC) parameters regarding NM characterization as well as the limitations of toxicological assays originally designed for soluble chemicals. Hence, it is becoming increasingly clear that not all of these data are reliable or relevant from the regulatory perspective. The aim of this systematic review is to investigate the extent of studies on genotoxicity of NMs that can be considered reliable and relevant by current standards and bring focus to what is needed for a study to be useful from the regulatory point of view. Due to the vast number of studies available, we chose to limit our search to two large groups, which have raised substantial interest in recent years: nanofibers (including nanotubes) and metal-containing nanoparticles. Focusing on peer-reviewed publications, we evaluated the completeness of PC characterization of the tested NMs, documentation of the model system, study design, and results according to the quality assessment approach developed in the EU FP-7 GUIDEnano project. Further, building on recently published recommendations for best practices in nanogenotoxicology research, we created a set of criteria that address assay-specific reliability and relevance for risk assessment purposes. Articles were then reviewed, the qualifying publications discussed, and the most common shortcomings in NM genotoxicity studies highlighted. Moreover, several EU projects under the FP7 and H2020 framework set the aim to collectively feed the information they produced into the eNanoMapper database. As a result, and over the years, the eNanoMapper database has been extended with data of various quality depending on the existing knowledge at the time of entry. These activities are highly relevant since negative results are often not published. Here, we have reviewed the NanoInformaTIX instance under the eNanoMapper database, which hosts data from nine EU initiatives. We evaluated the data quality and the feasibility of use of the data from a regulatory perspective for each experimental entry.

The impact of engineered nanomaterials on the environment: Release mechanism, toxicity, transformation, and remediation

The presence and longevity of nanomaterials in the ecosystem, as well as their properties, account for environmental toxicity. When nanomaterials in terrestrial and aquatic systems are exposed to the prevailing environmental conditions, they undergo various transformations such as dissociation, dissolution, and aggregation, which affects the food chain. The toxicity of nanomaterials is influenced by a variety of factors, including environmental factors and its physico-chemical characteristics. Bioaccumulation, biotransformation, and biomagnification are the mechanisms that have been identified for determining the fate of nanomaterials. The route taken by nanomaterials to reach living cells provides us with information about their toxicity profile. This review discusses the recent advances in the transport, transformation, and fate of nanomaterials after they are released into the environment. The review also discusses how nanoparticles affect lower trophic organisms through direct contact, the impact of nanoparticles on higher trophic organisms, and the possible options for remediation.

Environmentally Toxic Solid Nanoparticles in Noradrenergic and Dopaminergic Nuclei and Cerebellum of Metropolitan Mexico City Children and Young Adults with Neural Quadruple Misfolded Protein Pathologies and High Exposures to Nano Particulate Matter

Quadruple aberrant hyperphosphorylated tau, beta-amyloid, α-synuclein and TDP-43 neuropathology and metal solid nanoparticles (NPs) are documented in the brains of children and young adults exposed to Metropolitan Mexico City (MMC) pollution. We investigated environmental NPs reaching noradrenergic and dopaminergic nuclei and the cerebellum and their associated ultrastructural alterations. Here, we identify NPs in the locus coeruleus (LC), substantia nigrae (SN) and cerebellum by transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometry (EDX) in 197 samples from 179 MMC residents, aged 25.9 ± 9.2 years and seven older adults aged 63 ± 14.5 years. Fe, Ti, Hg, W, Al and Zn spherical and acicular NPs were identified in the SN, LC and cerebellar neural and vascular mitochondria, endoplasmic reticulum, Golgi, neuromelanin, heterochromatin and nuclear pore complexes (NPCs) along with early and progressive neurovascular damage and cerebellar endothelial erythrophagocytosis. Strikingly, FeNPs 4 ± 1 nm and Hg NPs 8 ± 2 nm were seen predominantly in the LC and SN. Nanoparticles could serve as a common denominator for misfolded proteins and could play a role in altering and obstructing NPCs. The NPs/carbon monoxide correlation is potentially useful for evaluating early neurodegeneration risk in urbanites. Early life NP exposures pose high risk to brains for development of lethal neurologic outcomes. NP emissions sources ought to be clearly recognized, regulated, and monitored; future generations are at stake.

Quercetin Alleviates the Immunotoxic Impact Mediated by Oxidative Stress and Inflammation Induced by Doxorubicin Exposure in Rats

Doxorubicin (DOX) is a chemotherapeutic agent against hematogenous and solid tumors with undesirable side effects including immunosuppression. Quercetin (QUR), a natural flavonoid abundant in fruits and vegetables, has a potent antioxidant activity. The aim of the current study was to assess the impact of QUR on DOX-induced hematological and immunological dysfunctions in a rodent model. Randomly grouped rats were treated as follows: control, QUR alone (50 mg/kg for 15 days per os), DOX alone (2.5 mg/kg I/P, three times a week, for two weeks), and co-treated rats with QUR for 15 days prior to and concomitantly with DOX (for two weeks), at the doses intended for groups two and three. DOX alone significantly disrupted the erythrogram and leukogram variables. Serum immunoglobulin (IgG, IgM, and IgE) levels and the activities of catalase (CAT) and superoxide dismutase (SOD) in spleen were declined. The DNA damage traits in spleen were elevated with an upregulation of the expression of the apoptotic markers (p53 and Caspase-3 genes) and the proinflammatory cytokines (IL-6 and TNF-α genes), while the expression of CAT gene was downregulated. These biochemical changes were accompanied by morphological changes in the spleen of DOX-treated rats. Co-treatment with QUR abated most of the DOX-mediated alterations in hematological variables, serum immunoglobulins, and spleen antioxidant status, pro-inflammatory and apoptotic responses, and histopathological alterations. In essence, these data suggest that QUR alleviated DOX-induced toxicities on the bone marrow, spleen, and antibody-producing cells. Supplementation of chemotherapy patients with QUR could circumvent the DOX-induced inflammation and immunotoxicity, and thus prevent chemotherapy failure.

A comparison of hepatotoxicity induced by different lengths of tungsten trioxide nanorods and the protective effects of melatonin in BALB/c mice

Tungsten trioxide nanoparticles (WO₃ NPs) have shown increasing promise in biological and biomedical fields in recent years. However, their possible hazards, especially the adverse effects related to their sizes on human health and environment, are still yet poorly understood. In this study, we compared the hepatotoxicity in mice induced by WO₃ nanorods of two different lengths (125-200 nm and 0.8-2 μm) via intraperitoneal injection, and explored the protective role of melatonin, an antioxidant, against the hepatotoxicity. The results showed that 10 mg/kg/day of shorter WO₃ nanorods could cause obvious hepatic function impairment, histopathological lesions, and significant enhancement in levels of oxidative stress and inflammation in mouse liver. However, similar effects were found only in the 20 mg/kg/day longer WO₃ nanorods-treated mice, and these adverse effects were attenuated by pretreatment with melatonin. These findings indicate that WO₃ nanorods can exert hepatotoxicity in mice in a dose- and length-dependent manner, and that shorter WO₃ nanorods cause more severe hepatotoxicity than their longer counterparts. Melatonin could serve as an effective protective agent against the longer WO₃ nanorods-induced hepatotoxicity by decreasing the oxidative stress level. This study is important for determining the environmental and human health risks of exposure to WO₃ NPs and their size-dependent toxicity, and provides an appealing strategy to avoid the adverse effects. WO₃ nanorods with different lengths can exert hepatotoxicity in mice, in a dose- and length-dependent manner. Short WO₃ nanorods causes more severe hepatic injury than long ones. Melatonin exhibits an effectively protective effects against WO₃ nanorods-induced hepatic injury through reducing the oxidative stress level.

Comparative outcomes of exposing human liver and kidney cell lines to tungstate and molybdate

Tungsten has no known function in humans and is a relatively new contaminant, whereas molybdenum, its congener in the periodic table, is a nutritionally essential element. In addition to early studies on molybdosis in ruminants, their toxic effects in the form of tungstate and molybdate have been addressed primarily in rodents and are predominantly mediated by inducing oxidative stress in various tissues. The purpose of this study was to evaluate the differences between tungstate and molybdate in human liver (HepG2) and kidney (HEK293) cell lines in terms of retention in cells, effect on reactive oxygen species, and activities of xanthine oxidase and phosphatases. The cell lines were exposed to tungstate or molybdate (1 µM to 10 mM) for 24 h, lysed and analyzed for the above biochemical parameters. Despite the chemical similarity of the two anions, cell-specific differential effects were observed. At all concentrations, tungstate was retained more in HEK293 cells while molybdate was retained more in HepG2 cells. HepG2 cells were more sensitive to tungstate than molybdate, showing reduced viability at concentrations as low as 10 µM. Exposure to either anion resulted in the inhibition of protein tyrosine phosphatases at 1 mM and an increased production of reactive oxygen species (ROS) at 100 µM despite their inhibition of the ROS-producing molybdenum enzyme xanthine oxidase. In conclusion, the results indicate that excess of nutritionally essential molybdate or non-essential tungstate causes toxicity by affecting ROS- and phosphorylation-dependent signaling pathways and ensuing gene expression.

A Review of Tungsten Resources and Potential Extraction from Mine Waste

Tungsten is recognized as a critical metal due to its unique properties, economic importance, and limited sources of supply. It has wide applications where hardness, high density, high wear, and high-temperature resistance are required, such as in mining, construction, energy generation, electronics, aerospace, and defense sectors. The two primary tungsten minerals, and the only minerals of economic importance, are wolframite and scheelite. Secondary tungsten minerals are rare and generated by hydrothermal or supergene alteration rather than by atmospheric weathering. There are no reported concerns for tungsten toxicity. However, tungsten tailings and other residues may represent severe risks to human health and the environment. Tungsten metal scrap is the only secondary source for this metal but reprocessing of tungsten tailings may also become important in the future. Enhanced gravity separation, wet high-intensity magnetic separation, and flotation have been reported to be successful in reprocessing tungsten tailings, while bioleaching can assist with removing some toxic elements. In 2020, the world’s tungsten mine production was estimated at 84 kt of tungsten (106 kt WO3), with known tungsten reserves of 3400 kt. In addition, old tungsten tailings deposits may have great potential for exploration. The incomplete statistics indicate about 96 kt of tungsten content in those deposits, with an average grade of 0.1% WO3 (versus typical grades of 0.3–1% in primary deposits). This paper aims to provide an overview of tungsten minerals, tungsten primary and secondary resources, and tungsten mine waste, including its environmental risks and potential for reprocessing.

How macrophages respond to two-dimensional materials: a critical overview focusing on toxicity

With wider use of graphene-based materials and other two-dimensional (2 D) materials in various fields, including electronics, composites, biomedicine, etc., 2 D materials can trigger undesired effects at cellular, tissue and organ level. Macrophages can be found in many organs. They are one of the most important cells in the immune system and they are relevant in the study of nanomaterials as they phagocytose them. Nanomaterials have multi-faceted effects on phagocytic immune cells like macrophages, showing signs of inflammation in the form of pro-inflammatory cytokine or reactive oxidation species production, or upregulation of activation markers due to the presence of these foreign bodies. This review is catered to researchers interested in the potential impact and toxicity of 2 D materials, particularly in macrophages, focusing on few-layer graphene, graphene oxide, graphene quantum dots, as well as other promising 2 D materials containing molybdenum, manganese, boron, phosphorus and tungsten. We describe applications relevant to the growing area of 2 D materials research, and the possible risks of ions and molecules used in the production of these promising 2 D materials, or those produced by the degradation and dissolution of 2 D materials.

Cytotoxic and genotoxic assessment of tungsten oxide nanoparticles in Allium cepa cells by Allium ana-telophase and comet assays

Tungsten oxide nanoparticles or nanopowder (WO₃NPs) is commonly used in various industries and also in biomedical applications such as additives, pigments, and biomedical sensors. Non-judicious excessive use of these nanoparticles (NPs) could be a serious human health concern. Therefore, the current study aimed to explore the cytotoxic and genotoxic assessment of WO₃NPs through Allium cepa anaphase-telophase and comet assays. Nanoparticles were characterized through the scanning and transmission electron microscopy (TEM), zetasizer, and energy-dispersive X-ray spectroscopy. The mean size and the average diameter of WO₃NPs were determined as 21.57 ± 2.48 nm and 349.42 ± 80.65 nm using TEM and a Zetasizer measurement system, respectively. Five concentrations (12.5 mg/L, 25 mg/L, 50 mg/L, 75 mg/L, and 100 mg/L) of WO₃NPs were employed on the Allium cepa (A. cepa) roots for 4 h. Significant (p ≤ 0.05) decrease in mitotic index (MI) was shown by WO₃NPs at all concentrations. The increase of chromosomal aberrations (CAs) was also observed in a concentration-dependent manner due to the WO₃NPs exposure. There was a significant increase (p ≤ 0.05) in DNA damage at all concentrations of WO₃NPs on the A. cepa cells. It was concluded that WO₃NPs had cytotoxic and genotoxic effects on A. cepa meristematic cells. Moreover, further cytogenetic effects of WO₃NPs should be investigated at the molecular level to assess its safety margin.

Comparative study of toxicological assessment of yttrium oxide nano- and microparticles in Wistar rats after 28 days of repeated oral administration

Despite their enormous advantages, nanoparticles (NPs) have elicited disquiet over their safety. Among the numerous NPs, yttrium oxide (Y2O3) NPs are utilised in many applications. However, knowledge about their toxicity is limited, and it is imperative to investigate their potential adverse effects. Therefore, this study explored the effect of 28 days of repeated oral exposure of Wistar rats to 30, 120 and 480 mg/kg body weight (bw) per day of Y2O3 NPs and microparticles (MPs). Before initiation of the study, characterisation of the particles by transmission electron microscopy, dynamic light scattering, Brunauer-Emmett-Teller and laser Doppler velocimetry was undertaken. Genotoxicity was evaluated using the comet and micronucleus (MN) assays. Biochemical markers aspartate transaminase, alanine transaminase, alkaline phosphatase, malondialdehyde, superoxide dismutase, reduced glutathione, catalase and lactate dehydrogenase in serum, liver and kidney were determined. Bioaccumulation of the particles was analysed by inductively coupled plasma optical emission spectrometry. The results of the comet and MN assays showed significant differences between the control and groups treated with 120 and 480 mg/kg bw/day Y2O3 NPs. Significant biochemical alterations were also observed at 120 and 480 mg/kg bw/day. Haematological and histopathological changes were documented. Yttrium (Y) biodistribution was detected in liver, kidney, blood, intestine, lungs, spleen, heart and brain in a dose- and the organ-dependent manner in both the particles. Further, the highest levels of Y were found in the liver and the lowest in the brain of the treated rats. More of the Y from NPs was excreted in the urine than in the faeces. Furthermore, NP-treated rats exhibited much higher absorption and tissue accumulation. These interpretations furnish rudimentary data of the apparent genotoxicity of NPs and MPs of Y2O3 as well as the biodistribution of Y. A no-observed adverse effect level of 30 mg/kg bw/day was found after oral exposure of rats to Y2O3 NPs.

The Toxicity Of Metallic Nanoparticles On Liver: The Subcellular Damages, Mechanisms, And Outcomes

Metallic nanoparticles (MNPs) are new engineering materials with broad prospects for biomedical applications; thus, their biosafety has drawn great concern. The liver is the main detoxification organ of vertebrates. However, many issues concerning the interactions between MNPs and biological systems (cells and tissues) are unclear, particularly the toxic effects of MNPs on hepatocytes and other liver cells. Numerous researchers have shown that some MNPs can induce decreased cell survival rate, production of reactive oxygen species (ROS), mitochondrial damage, DNA strand breaks, and even autophagy, pyroptosis, apoptosis, or other forms of cell death. Our review focuses on the recent researches on the liver toxicity of MNPs and its mechanisms at cellular and subcellular levels to provide a scientific basis for the subsequent hepatotoxicity studies of MNPs.

Systematic comparison of methods for determining the in vivo biodistribution of porous nanostructured injectable inorganic particles

With a wide variety of biodistribution measurement techniques reported in the literature, it is important to perform side-by-side comparisons of results obtained with different methods on the same particle platform, to determine differences across methods, highlight advantages and disadvantages, and inform methods selection according to specific applications. Inorganic nanostructured particles (INPs) have gained a central role in the development of injectable delivery vectors thanks to their controllable design, biocompatibility, and favorable degradation kinetic. Thus, accurate determination of in vivo biodistribution of INPs is a key aspect of developing and optimizing this class of delivery vectors. In this study, a systematic comparison of spectroscopy (inductively coupled plasma optical emission spectroscopy), fluorescence (in vivo imaging system, confocal microscopy, and plate reader), and radiolabeling (gamma counter)-based techniques is performed to assess the accuracy and sensitivity of biodistribution measurements in mice. Each method is evaluated on porous silicon particles, an established and versatile injectable delivery platform. Biodistribution is evaluated in all major organs and compared in terms of absolute results (%ID/g and %ID/organ when possible) and sensitivity (σ_%). Finally, we discuss how these results can be extended to inform method selection for other platforms and specific applications, with an outlook to potential benefit for pre-clinical and clinical studies. Overall, this study presents a new practical guide for selection of in vivo biodistribution methods that yield quantitative results. STATEMENT OF SIGNIFICANCE: The significance of this work lies in the use of a single platform to test performances of different biodistribution methods in vivo, with a strict quantitative metric. These results, united with the qualitative comparison of advantages and disadvantages of each technique, are aimed at supporting the rational choice of each different method according to the specific application, to improve the quantitative description of biodistribution results that will be published by others in the future.

Repeated oral dose toxicity study of nickel oxide nanoparticles in Wistar rats: a histological and biochemical perspective

Despite the increasing use of nickel oxide (NiO) nanoparticles (NPs), limited information is available on their toxicological effects. Health consequences of 28 days repeated oral exposure to NiO NPs have not been explored thoroughly. Hence, toxicity investigations were performed after 28-day daily exposure in albino Wistar rats with NiO NPs following Organization for Economic Co-operation and Development test guideline 407. Histopathology, biochemical indices including oxidative stress and biodistribution patterns were evaluated to decipher the toxicological impact of NiO NPs. NiO NP characterization by transmission electron microscopy showed an average size of 12.9 (±3.4) nm. Histological studies depicted a prominent impact on the vital organs of the rats. A dose-dependent rise in both aminotransferase enzyme values was recorded in the homogenates of liver and kidney tissues. A significant decrease in superoxide dismutase activity and increase in catalase activity was noted. Further, a dose-dependent decrease in reduced glutathione content was recorded in rats, which suggested generation of reactive oxygen species and oxidative stress. Increase in the malondialdehyde levels was observed with an increase in the dose substantiating the antioxidant enzyme activity profiles. Biodistribution studies indicated maximum accumulation of Ni content in liver followed by kidney. Excretion of Ni was predominantly through feces and a little through renal clearance. Our study indicated that NiO NPs adversely alter the biochemical profile of the rats and cause histological damage. Further investigations are warranted to address the mechanism by which physiological path these NiO NPs exhibit their toxic nature in in vivo.

Comparative Assessment of Tungsten Toxicity in the Absence or Presence of Other Metals

Tungsten is a refractory metal that is used in a wide range of applications. It was initially perceived that tungsten was immobile in the environment, supporting tungsten as an alternative for lead and uranium in munition and military applications. Recent studies report movement and detection of tungsten in soil and potable water sources, increasing the risk of human exposure. In addition, experimental research studies observed adverse health effects associated with exposure to tungsten alloys, raising concerns on tungsten toxicity with questions surrounding the safety of exposure to tungsten alone or in mixtures with other metals. Tungsten is commonly used as an alloy with nickel and cobalt in many applications to adjust hardness and thermal and electrical conductivity. This review addresses the current state of knowledge in regard to the mechanisms of toxicity of tungsten in the absence or presence of other metals with a specific focus on mixtures containing nickel and cobalt, the most common components of tungsten alloy.

Genotoxicity, biochemical, and biodistribution studies of magnesium oxide nano and microparticles in albino wistar rats after 28-day repeated oral exposure

Increased utilization and exposure levels of Magnesium oxide (MgO) nanoparticles (NPs) to humans and environment may raise unexpected consequences. The goal of this study was to evaluate the toxicological implications of MgO NPs and MPs after 28 day repeated oral administration in Wistar rats with three different doses (250, 500, and 1000 mg/kg). The MgO particles were characterised systematically in order to get more insights of the toxicological behaviour. MgO NPs induced significant DNA damage and aberrations in chromosomes. Moreover, hepatic enzymes released into the systemic circulation caused significant elevated levels of physiological enzymes in blood. NPs could interfere with proteins and enzymes and alter the redox balance in cell environment. Significant accumulation of Mg in all tissues and clearance via urine and faeces was noted in size dependent kinetics. Oral administration of MgO NPs altered the biochemical and genotoxic parameters in dose dependent and gender independent manner.

Toxicity assessment of chlorpyrifos-degrading fungal bio-composites and their environmental risks

Bioremediation techniques coupling with functional microorganisms have emerged as the most promising approaches for in-situ elimination of pesticide residue. However, the environmental safety of bio-products based on microorganisms or engineered enzymes was rarely known. Here, we described the toxicity assessment of two previously fabricated fungal bio-composites which were used for the biodegradation of chlorpyrifos, to clarify their potential risks on the environment and non-target organisms. Firstly, the acute and chronic toxicity of prepared bio-composites were evaluated using mice and rabbits, indicating neither acute nor chronic effect was induced via short-term or continuous exposure. Then, the acute mortality on zebrafish was investigated, which implied the application of fungal bio-composites had no lethal risk on aquatic organisms. Meanwhile, the assessment on soil organic matters suggested that no threat was posed to soil quality. Finally, by monitoring, the germination of cabbage was not affected by the exposure to two bio-products. Therefore, the application of fungal bio-composites for chlorpyrifos elimination cannot induce toxic risk to the environment and non-target organisms, which insured the safety of these engineered bio-products for realistic management of pesticide residue, and provided new insights for further development of bioremediation techniques based on functional microorganisms.

Dacarbazine nanoparticle topical delivery system for the treatment of melanoma

Dacarbazine (DZ) is poorly soluble in water with the short half-life in blood circulation, low rate of response with the toxic effect which ultimately limits its utilization of the treatment of skin cancer. In view of this background current study was designed for development of dacarbazine laden nanoparticle (DZNP) and dacarbazine laden nanocream (DZNC) topical delivery system for the treatment of melanoma. Firstly DZNP was prepared. By using DZNP its cream formulation prepared for topic drug delivery for melanoma. Dacarbazine nanoparticle and its cream were evaluated for morphology, drug load capacity, efficiency of nanoencapsulation and size of particle and zeta potential, Transmission Electron Microscopy (TEM), determination of pH, spreadability and viscosity, in vitro drug release capacity and its cytotoxic potential. The particle size of DZNP and DZNC was 16.3 ± 8.1 nm and 16.9 ± 7.8 nm respectively. pH value and spreadability of nanoparticle cream were found to be 6.7 ± 0.14 g cm/sec and 55.23 ± 3.13 g cm/sec respectively. Nanoencapsulation efficiency and Drug loading capacity were 67.4 ± 3.5% and 6.73 mg/10 mg respectively. IC50 of dacarbazine nanoparticle was 0.19 mg/ml while it was 0.63 mg/ml for nanoparticle cream. It can be concluded that DZNP and its cream can be effectively used as a topical formulation for the treatment of melanoma.