Engineered Metal Nanoparticles Research Articles

Silver nanoparticle functionalized by glutamine and conjugated with thiosemicarbazide induces apoptosis in colon cancer cell line

The high mortality rate of colon cancer indicates the insufficient efficacy of current chemotherapy. Thus, the discussion on engineered metal nanoparticles in the treatment of the disease has been considered. In this study, silver nanoparticles were functionalized with glutamine and conjugated with thiosemiccarbazide. Then, anticancer mechanism of Ag@Gln-TSC NPs in a colon cancer cell line (SW480) was investigated. Characterizing Ag@Gln-TSC NPs by FT-IR, XRD, EDS-mapping, DLS, zeta potential, and SEM and TEM microscopy revealed that the Ag@Gln-TSC NPs were correctly synthesized, the particles were spherical, with surface charge of − 27.3 mV, high thermal stability and low agglomeration level. Using MTT assay we found that Ag@Gln-TSC NPs were significantly more toxic for colon cancer cells than normal fibroblast cells with IC50 of 88 and 186 µg/mL, respectively. Flow cytometry analysis showed that treating colon cancer cells with Ag@Gln-TSC NPs leads to a considerable increase in the frequency of apoptotic cells (85.9% of the cells) and increased cell cycle arrest at the S phase. Also, several apoptotic features, including hyperactivity of caspase-3 (5.15 folds), increased expression of CASP8 gene (3.8 folds), and apoptotic nuclear alterations were noticed in the nanoparticle treated cells. Furthermore, treating colon cancer cells with Ag@Gln-TSC NPs caused significant down-regulation of the HULC Lnc-RNA and PPFIA4 oncogene by 0.3 and 0.6 folds, respectively. Overall, this work showed that Ag@Gln-TSC NPs can effectively inhibit colon cancer cells through the activation of apoptotic pathways, a feature that can be considered more in studies in the field of colon cancer treatment.

Intestinal Toxicity of Metal Nanoparticles: Silver Nanoparticles Disorder the Intestinal Immune Microenvironment.

Albeit numerous studies have been conducted on the toxicity evaluation of engineered metal nanoparticles (NPs), significant knowledge gaps remain regarding the influence of oral exposure to metal NPs on the intestine system, especially the effects on the intestinal immune microenvironment. Herein, we examined the long-term effects of representative engineered metal NPs on the intestine through oral exposure and identified silver NPs (Ag NPs) that resulted in severe damage. Oral Ag NP exposure damaged the epithelial structure, reduced the thickness of the mucosal layer, and altered the intestinal microbiota. Particularly, the reduced thickness of the mucosal layer increased the phagocytosis of Ag NPs by dendritic cells (DCs). Comprehensive animal and in vitro experiments unraveled that Ag NPs directly interacted with DCs, resulting in the abnormal activation of DCs by generating reactive oxygen species and inducing uncontrolled apoptosis. Furthermore, our data unveiled that the interactions between Ag NPs and DCs reduced the proportion of CD103+CD11b+ DCs and induced Th17 cell activation with inhibition of regulatory T-cell differentiation, resulting in the disordered immune microenvironment in the intestine. Collectively, these results represent a new point of view on the cytotoxicity of Ag NPs on the intestine system. This study provides additional insights into the health risks of engineered metal NPs, especially Ag NPs.

The Potential Impact of Ayurvedic Traditional Bhasma on SARS-CoV- 2- Induced Pathogenesis

Abstract: In India, the presently ongoing infectious COVID-19 wave is caused by the delta variant of SARS-CoV-2 which has also led thousands of causalities across the globe. The government and healthcare agencies are hovering for effective strategies to counter the pandemic. The application of nanotechnology and repurposing of drugs are found an effective approach, not obsolete but partly in managing the COVID-19 disease. It has also immensely boomed the search of productive, reliable, cost-effective, and bio-assimilable alternative solutions. Since ancient times, the traditionally employed Ayurvedic bhasmas opted for diverse infectious diseases, which are now justified as a nanomedicine that could be applied for managing COVID-19 related health anomalies. Like currently existing engineered metal nanoparticles (NPs), the bhasma nanoparticles (BNPs) are also packed with unique physicochemical properties including multi-elemental nanocrystalline composition, size, shape, dissolution, surface charge, hydrophobicity, multi-pathway regulatory, and modulatory effects. Here, it is hypothesized that due to these conformational- and configurational- based physicochemical advantages, bhasma NPs might have promising potential to manage the COVID-19 pandemic and can reduce the incidence of pneumonia-like common lung infections in children as well as old-age-related inflammatory diseases by immunomodulatory, anti-inflammatory, antiviral, and adjuvant-related characteristics.

Periostracum of bivalve mollusk shells for sampling engineered metal nanoparticles: A case study of silver-based nanoparticles in Canada's experimental lake.

Given the ability of engineered metal nanoparticles to be transformed in natural waters in unpredictable manners, various sampling methods must be developed. Here, we took a novel approach to collection silver nanoparticles (AgNPs) that involved the use of the intact periostracum, the outer proteinaceous organic layer, of freshwater unionid mussels Pyganodon sp. Eight adult mussels were collected in August 2019 from a small boreal lake (L222) at the International Institute for Sustainable Development - Experimental Lakes Area (northwestern Ontario), which had been dosed with 15kg of poly(vinylpyrrolidone)-coated silver nanoparticles (PVP-AgNPs) in 2014-2015. Additionally, three adult mussels were collected from a control lake (L375). Numerous silica (SiO2) diatom frustules were adhered to periostracum of all mussels. Intact periostracum promotes the formation of layer composed of diatoms and sand grains. The Ag content in soft tissues and shells of the mussels from L375 was as low as ≤ 0.1 μg/g. In mussels from L222, Ag concentrations in the periostracum of five shells were in detectable amounts (1-4 μg/g); in three shells concentrations were as high as 86, 122, and 494 μg/g. The underlying mineral shell is depleted in Ag (<0.1 μg/g). The Ag content in soft tissue organs (whole body) ranged from 44 to 191 μg/g. AgNPs occur on the surface of both periostracum and diatoms. Single AgNPs (d=20-60nm) were partly sulfidized to Ag2S. The observed AgNPs often form aggregates with an average and a maximal size of circa 100nm and 1.5 μm, respectively. Scraping small fragments of intact periostracum of unionid shell is non-lethal to mussels, and is easy to do under field conditions. This simple sampling protocol could be used to detect metal-based nanoparticles (engineered or accidental) with the use of unionid and dreissenid bivalves.

Green synthesis of metallic nanoparticles: Advancements and future perspectives

As an alternative to chemical and physical approaches, green synthesis of metal nanoparticles is a developing area in the field of bio-nanotechnology and offers economic and environmental benefits. In the field of health and hygiene, engineered metal nanoparticles have increased their popularity due to their effectiveness in penetrating living systems. Metal nanoparticles can be efficiently biosynthesized using a range of microbes and plant extracts. Green synthesis of these nanoparticles and their use in diverse technologies have a bright future due to the shifting perspectives of the international community on sustainable development, environmental improvement, and the reduction of dangerous man-made waste. The focus of the current review was primarily on various methods employed for the green synthesis of metal nanoparticles, which is a more environment-friendly technique for creating metallic nanocarriers and altering their surfaces, use these metal nanoparticles, including metal sulfides, zinc oxide, copper, gold, platinum, and palladium, as well as nano metal-organic frameworks, in drug delivery systems.

Influence of Aging on Bioaccumulation and Toxicity of Copper Oxide Nanoparticles and Dissolved Copper in the Sediment-Dwelling Oligochaete Tubifex tubifex: A Long-Term Study Using a Stable Copper Isotope.

For engineered metal nanoparticles (NPs), such as copper oxide (CuO) NPs, the sediment is recognized as a major compartment for NP accumulation. Sediment-dwelling organisms, such as the worm Tubifex tubifex, will be at particular risk of metal and metal NP exposure. However, a range of complex transformation processes in the sediment affects NP bioavailability and toxicity as the contamination ages. The objective of this study was to examine bioaccumulation and adverse effects of CuO NPs in T. tubifex compared to dissolved Cu (administered as CuCl2) and the influence of aging of spiked sediment. This was done in a 28-day exposure experiment with T. tubifex incubated in clean sediment or freshly spiked sediment with different concentrations of dissolved Cu (up to 230 μg g−1 dw) or CuO NPs (up to 40 μg g−1 dw). The experiment was repeated with the same sediments after it had been aged for 2 years. To obtain a distinct isotopic signature compared to background Cu, both Cu forms were based on the stable isotope 65Cu (>99%). The 28-day exposure to sediment-associated dissolved 65Cu and 65CuO NPs resulted in a clear concentration-dependent increase in the T. tubifex 65Cu body burden. However, despite the elevated 65Cu body burdens in exposed worms, limited adverse effects were observed in either of the two experiments (e.g., above 80% survival in all treatments, low or no effects on the growth rate, feeding rate, and reproduction). Organisms exposed to aged sediments had lower body burdens of 65Cu than those exposed to freshly spiked sediments and we suggest that aging decreases the bioavailability of both 65Cu forms. In this study, the use of a stable isotope made it possible to use environmentally realistic Cu concentrations and, at the same time, differentiate between newly accumulated 65Cu and background Cu in experimental samples despite the high background Cu concentrations in sediment and T. tubifex tissue. Realistic exposure concentrations and aging of NPs should preferably be included in future studies to increase environmental realism to accurately predict the environmental risk of metal NPs.

Toxic Effect of Metal-Based Nanomaterials on Representatives of Marine Ecosystems: A Review

The review summarizes the recent data on the toxic effect that engineered metal nanoparticles (NPs) and their oxides (Ag, Au, Cu, CuO, zero-valent iron, TiO2, and ZnO) exert on marine organisms of various taxonomic groups. Toxicity is considered with due regard of the size effects and physicochemical properties of NPs. Available data indicate that metallic NPs may adversely affect algae, bacteria, mollusks, worms, arthropods, echinoderms, chordates, etc. Toxic effects vary from reproductive disorders to death. Only scarce data are available on the NP effect on marine vertebrates (e.g., marine fish). The factors that affect the NP toxicity in an aqueous environment include the physicochemical properties of NPs, species specificities of the test organism, and parameters of the aqueous environment (in particular, salinity, temperature and pH). Exact relationships between the factors and NP toxicity are still poorly understood. In particular, there is no consensus on how salinity affects the NP toxicity in an aqueous environment. Putative mechanisms of NP toxicity include oxidative stress, impaired cell membrane integrity, inflammatory processes with consequent cell dysfunction, DNA damage, and genetic mutations. NPs easily persist within organisms and consequently have a high potential to accumulate in marine food chains. Lack of standardized techniques to detect metallic and metal oxide NPs and weak or absent relevant legislation complicate toxicology studies in marine ecosystems. The above circumstances make it necessary to further evaluate the safety of metallic NPs for marine organisms and especially vertebrates, to study the distant effects associated with NP transition and accumulation in marine food chains, and to unify the respective research protocols. The exact role of environmental factors in modulating NP toxicity and the mechanisms of NP toxicity are also important issues to address in future studies.

Neuroprotective effects of insulin like growth factor-1 on engineered metal nanoparticles Ag, Cu and Al induced blood-brain barrier breakdown, edema formation, oxidative stress, upregulation of neuronal nitric oxide synthase and brain pathology.

Military personnel are vulnerable to environmental or industrial exposure of engineered nanoparticles (NPs) from metals. Long-term exposure of NPs from various sources affect sensory-motor or cognitive brain functions. Thus, a possibility exists that chronic exposure of NPs affect blood-brain barrier (BBB) breakdown and brain pathology by inducing oxidative stress and/or nitric oxide production. This hypothesis was examined in the rat intoxicated with Ag, Cu or Al (50-60nm) nanoparticles (50mg/kg, i.p. once daily) for 7 days. In these NPs treated rats the BBB permeability, brain edema, neuronal nitric oxide synthase (nNOS) immunoreactivity and brain oxidants levels, e.g., myeloperoxidase (MP), malondialdehyde (MD) and glutathione (GT) was examined on the 8th day. Cu and Ag but not Al nanoparticles increased the MP and MD levels by twofold in the brain although, GT showed 50% decline. At this time increase in brain water content and BBB breakdown to protein tracers were seen in areas exhibiting nNOS positive neurons and cell injuries. Pretreatment with insulin like growth factor-1 (IGF-1) in high doses (1μg/kg, i.v. but not 0.5μg/kg daily for 7 days) together with NPs significantly reduced the oxidative stress, nNOS upregulation, BBB breakdown, edema formation and cell injuries. These novel observations demonstrate that (i) NPs depending on their metal constituent (Cu, Ag but not Al) induce oxidative stress and nNOS expression leading to BBB disruption, brain edema and cell damage, and (ii) IGF-1 depending on doses exerts powerful neuroprotection against nanoneurotoxicity, not reported earlier.

Toxicity Going Nano: Ionic Versus Engineered Cu Nanoparticles Impacts on the Physiological Fitness of the Model Diatom Phaeodactylum tricornutum

Increasing input of Metal Engineered Nano Particles (MeENPs) in marine ecosystems has raised concerns about their potential toxicity on phytoplankton. Given the lack of knowledge on MeENPs impact on these important primary producers, the effects of Copper Oxide (CuO) ENPs on growth, physiology, pigment profiles, fatty acid (FA) metabolism, and oxidative stress were investigated in the model diatom Pheodactylum tricornutum, to provide suitable biomarkers of CuO ENP exposure versus its ionic counterpart. Diatom growth was inhibited by CuO ENPs but not Ionic Cu, suggesting CuO ENP cytotoxicity. Pulse Modulated Amplitude (PAM) phenotyping evidenced a decrease in the electron transport energy flux, pointing to a reduction in chemical energy generation following CuO ENPs exposure, as well as an increase in the content of the non-functional Cu-substituted chlorophyll a (CuChl a). A significant decrease in eicosapentaenoic acid (C20:5) associated with a significant rise in thylakoid membranes FAs reflected the activation of counteractive measures to photosynthetic impairment. Significant increase in the omega 6/omega 3 ratio, underline expectable negative repercussions to marine food webs. Increased thiobarbituric acid reactive substances reflected heightened oxidative stress by CuO ENP. Enhanced Glutathione Reductase and Ascorbate Peroxidase activity were also more evident for CuO ENPs than ionic Cu. Overall, observed molecular changes highlighted a battery of possible suitable biomarkers to efficiently determine the harmful effects of CuO ENPs. The results suggest that the occurrence and contamination of these new forms of metal contaminants can impose added stress to the marine diatom community, which could have significant impacts on marine ecosystems, namely through a reduction of the primary productivity, oxygen production and omega 6 production, all essential to sustain heterotrophic marine life.

Investigation of Cytotoxicity Apoptotic and Inflammatory Responses of Biosynthesized Zinc Oxide Nanoparticles from Ocimum sanctum Linn in Human Skin Keratinocyte (Hacat) and Human Lung Epithelial (A549) Cells.

Pristine and engineered metal nanoparticles are widely applied in various fields of industry, and as consequences, they are useful as well as harmful to human health and environment. This study aimed at synthesizing the green zinc oxide nanoparticles (ZnNPs) using the leaf extract of Ocimum sanctum Linn and assessing its toxicity on human skin epidermal (HaCaT) and human lung epithelial (A549) cells. The synthesized green ZnNPs (gZnNPs) were characterized by using dynamic light scattering (DLS) and a high-resolution transmission electron microscope. The average size of gZnNPs obtained was 62 nm with a spherical shape. The effects of gZnNPs on the viability of HaCaT and A549 cells were investigated using tetrazolium salt (MTT) for 24 h. We have seen more reduction of cell viability of A549 cells in comparison to HaCaT cells. The induction of intracellular reactive oxygen species (ROS) was measured using DCFDA assay and showed a slightly high intensity of green fluorescence in A549 than HaCaT cells. The different oxidative stress biomarkers such as ROS generation and lipid peroxide were increased, and GSH was decreased in a dose-dependent manner. The apoptotic and necrotic effect of gZnNPs in both cells was carried out using Annexin-V-FITC and propidium iodide staining. More apoptotic and necrotic cells were found at a higher concentration of gZnNPs exposure. Also, we determined the effect of gZnNPs at the molecular level by evaluating the apoptotic and inflammatory markers, in which gZnNPs downregulated Bcl2 and upregulated Bax, caspase-3, and TNF-α in HaCaT and A549 cells. Ultimately, gZnNPs exerted toxicity and apoptosis in HaCaT and A549 cells.

Green synthesis of ultrapure La(OH)3 nanoparticles by one-step method through spark ablation and electrospinning and its application to phosphate removal

La(OH)3 metal engineered nanoparticles (MENPs) are efficient phosphate binders; however, complex synthesis procedures and purity as well as agglomeration issues impede their development and practical applications. Herein, a green and a one-step method in combination with the spark ablation aerosol technology and electrospinning is proposed for the synthesis of La(OH)3 MENPs; further, their application as phosphate binders are elucidated as a proof the concept. Material characterization results confirm the successful synthesis of ultrapure La(OH)3 MENPs, which has not been achieved before via an environmentally friendly one-step procedure. Small angle X-ray scattering and X-ray photoelectron spectroscopy etching results show that La(OH)3 MENPs loading on the electrospun nanofibers are uniform in both two and three dimensions. The comparative tests revealed a high phosphate adsorption capacity (110.8 mg P/g La) and indicted that the La(OH)3 MENPs perform well; this was observed even under the interference of coexisting ions (Cl−, SO42−, NO3−, and F−) at different pH values. After three cycles of solution-shaking treatment, the release of La(OH)3 was less than 1 wt% (0.5 wt%), which was acceptable for an adsorbent. These results indicate that the La(OH)3 MENP-loaded nanofibers are practical phosphate binders due to the simple production methods, low manufacturing cost, and impressive capacity. The proposed method significantly shortens the loading process and is a promising alternative for not only the synthesis of the adsorbent, but also for other engineering materials where loading is needed.

Phytotoxic and Genotoxic Effects of Copper Nanoparticles in Coriander (Coriandrum sativum-Apiaceae).

Engineered metal nanoparticles have been widely used in several applications that may lead to increased exposure to the environment. In this study, we assessed the phytotoxic effect of various concentrations of copper nanoparticles CuNP, (200, 400 and 800 mg/L) on coriander (Coriandrum sativum) plants grown hydroponically. C. sativum plants treated with CuNP demonstrated decreased biomass and root length in comparison to control untreated plants. Additionally, decreased levels of photosynthetic pigments (chlorophyll a and b) were also seen in C. sativum plants treated with CuNP, as well as damage to the C. sativum root plasma membrane as demonstrated by Evan’s blue dye and increased electrolyte leakage. Moreover, our results exhibited increased levels of H2O2 and MDA on C. Sativum plants treated with CuNP. X-Ray Fluorescence (XRF) analysis confirmed that C. sativum treated with CuNP accumulated the latter in plant root tissues. Random amplified polymorphic DNA (RAPD) analysis confirmed the genotoxic effect of CuNP, which altered the C. sativum genome. This was shown by the different banding pattern of RAPD. Overall, our results exhibited that CuNP is toxic to C. sativum plants.

Amendment of Agricultural Soil with Metal Nanoparticles: Effects on Soil Enzyme Activity and Microbial Community Composition.

Several types of engineered nanoparticles (ENPs) are being considered for direct application to soils to reduce the application and degradation of pesticides, provide micronutrients, control pathogens, and increase crop yields. This study examined the effects of different metal ENPs and their dissolved ions on the microbial community composition and enzyme activity of agricultural soil amended with biosolids. The activity of five extracellular nutrient-cycling enzymes was measured in biosolid-amended soils treated with different concentrations (1, 10, or 100 mg ENP/kg soil) of silver (nAg), zinc oxide (nZnO), copper oxide (nCuO), or titanium dioxide (nTiO2) nanoparticles and their ions over a 30-day period. At 30 days, nZnO and nCuO either had no significant effect on soil enzyme activity or enhanced enzyme activity. In contrast, Ag inhibited selected enzymes when dosed in particulate or dissolved form (at 100 mg/kg). nTiO2 either had no significant effect or slightly decreased enzyme activity. Illumina MiSeq sequencing of microbial communities indicated a shift in soil microbial community composition upon exposure to high doses of metal ions or nAg and negligible shift in the presence of nTiO2. Some taxa responded differently to nAg and Ag+. This work shows how metal ENPs can impact soil enzyme activity and microbial community composition upon introduction into soils amended with biosolids, depending on their type, concentration, and dissolution behavior, hence providing much needed information for the sustainable application of nanotechnology in agriculture.

Effects of copper oxide nanoparticles and copper ions to zebrafish (Danio rerio) cells, embryos and fry

The use of engineered metal nanoparticles (NPs) is continuously increasing and so is the need for information regarding their toxicity. This study compares the toxicity of CuO NPs with ionic Cu in three zebrafish model systems; zebrafish hepatoma cell line (ZFL), fish embryo toxicity test (FET) and fry locomotion. In the ZFL tests, no significant cytotoxicity (cell death, decreased metabolic or cell membrane integrity) was detected for either treatment, though both significantly affected reactive oxygen species (ROS) production. Embryo mortality was affected by both Cu ions and CuO NPs with similar concentration-response relationships, whereas only Cu ions affected fry mortality (24h LC50≈30μM, ≈2mgCuL−1 for Cu ions and no significant mortality observed at up to 200μM, 12.7mgCuL−1 for CuO NP). Both Cu forms increased fry swimming activity during light cycles and decreased activity during dark cycles: Cu ions had significant impact at lower concentrations than CuO NPs. The implications are that Cu ions generally are more toxic than CuO NPs to embryos and fry but there is a marked difference in toxicity among the different zebrafish model systems. Metal NPs release into the environment may have adverse effects on fish and other aquatic organisms.

Photosynthetic efficiency predicts toxic effects of metal nanomaterials in phytoplankton

High Throughput Screening (HTS) using in vitro assessments at the subcellular level has great promise for screening new chemicals and emerging contaminants to identify high-risk candidates, but their linkage to ecological impacts has seldom been evaluated. We tested whether a battery of subcellular HTS tests could be used to accurately predict population-level effects of engineered metal nanoparticles (ENPs) on marine phytoplankton, important primary producers that support oceanic food webs. To overcome well-known difficulties of estimating ecologically meaningful toxicity parameters, we used novel Dynamic Energy Budget and Toxicodynamic (DEBtox) modeling techniques to evaluate impacts of ENPs on population growth rates. Our results show that population growth was negatively impacted by all four ENPs tested, but the HTS tests assessing many cell/physiological functions lacked predictive power at the population level. However, declining photosynthetic efficiency, a traditional physiological endpoint for photoautotrophs, was a good predictor of population level effects in phytoplankton. DEBtox techniques provided robust estimates of EC10 for population growth rates in exponentially growing batch cultures of phytoplankton, and should be widely useful for ecotoxicological testing. Adoption of HTS approaches for ecotoxicological assessment should carefully evaluate the predictive power of specific assays to minimize the risk that effects at higher levels of biological organization may go undetected.

Facile synthesis of Curcuma longa tuber powder engineered metal nanoparticles for bioimaging applications

Nanomaterials based fluorescent agents are rapidly becoming significant and promising transformative tools for improving medical diagnostics for extensive in vivo imaging modalities. Compared with conventional fluorescent agents, nano-fluorescence has capabilities to improve the in vivo detection and enriched targeting efficiencies. In our laboratory we synthesized fluorescent metal nanoparticles of silver, copper and iron using Curcuma longa tuber powder by simple reduction. The physicochemical properties of the synthesized metal nanoparticles were attained using UV–visible spectrophotometry, scanning electron microscopy with EDAX spectroscopy, dynamic light scattering, Fourier-transform infrared spectroscopy and X-ray diffraction. The Curcuma longa tuber powder has one of the bioactive compound Curcumin might act as a capping agent during the synthesis of nanoparticles. The synthesized metal nanoparticles fluorescence property was confirmed by spectrofluorometry. When compared with copper and iron nanoparticles the silver nanoparticles showed high fluorescence intensity under spectrofluorometry. Moreover, in vitro cell images of the silver nanoparticles in A549 cell lines also correlated with the results of spectrofluorometry. These silver nanoparticles show inspiring cell-imaging applications. They enter into cells without any further modifications, and the fluorescence property can be utilized for fluorescence-based cell imaging applications.

Engineered metal nanoparticles in the sub-nanomolar levels kill cancer cells.

BackgroundSmall metal nanoparticles obtained from animal blood were observed to be toxic to cultured cancer cells, whereas noncancerous cells were much less affected. In this work, engineered zinc and copper metal nanoparticles were produced from bulk metal rods by an underwater high-voltage discharge method. The metal nanoparticles were characterized by atomic force microscopy and X-ray photoelectron spectroscopy. The metal nanoparticles, with estimated diameters of 1 nm–2 nm, were determined to be more than 85% nonoxidized. A cell viability assay and high-resolution light microscopy showed that exposure of RG2, cultured rat brain glioma cancer cells, to the zinc and copper nanoparticles resulted in cell morphological changes, including decreased cell adherence, shrinking/rounding, nuclear condensation, and budding from cell bodies. The metal-induced cell injuries were similar to the effects of staurosporine, an active apoptotic reagent. The viability experiments conducted for zinc and copper yielded values of dissociation constants of 0.22±0.08 nmol/L (standard error [SE]) and 0.12±0.02 nmol/L (SE), respectively. The noncancerous astrocytes were not affected at the same conditions. Because metal nanoparticles were lethal to the cancer cells at sub-nanomolar concentrations, they are potentially important as nanomedicine.PurposeLethal concentrations of synthetic metal nanoparticles reported in the literature are a few orders of magnitude higher than the natural, blood-isolated metal nanoparticles; therefore, in this work, engineered metal nanoparticles were examined to mimic the properties of endogenous metal nanoparticles.Materials and methodsRG2, rat brain glioma cells CTX TNA2 brain rat astrocytes, obtained from the American Type Culture Collection, high-voltage discharge, atomic force microscope, X-ray photoelectron spectroscopy, high-resolution light microscopy, zeta potential measurements, and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay were used in this work.ResultsEngineered zinc and copper metal nanoparticles of size 1 nm–2 nm were lethal to cultured RG2 glioma cancer cells. Cell death was confirmed by MTT assay, showing that the relative viability of RG2 glioma cells is reduced in a dose-dependent manner at sub-nanomolar concentrations of the nanoparticles. The noncancerous astrocytes were not affected at the same conditions.ConclusionThe engineered and characterized zinc and copper nanoparticles are potentially significant as biomedicine.

Exploring methods for compositional and particle size analysis of noble metal nanoparticles in Daphnia magna

The identification and quantification of the bioaccumulation of noble metal engineered nanoparticles (ENPs) by aquatic organisms is of great relevance to understand the exposure and potential toxicity mechanisms of nanoscale materials.Four analytical scenarios were investigated in relation to various sized and composed noble metal (gold (Au), platinum (Pt) and silver (Ag)) ENPs during acute, short-term exposure of Daphnia (D.) magna. Next to the total elemental quantification of absorbed ENPs by D. magna, especially information on the size and particle distribution of ENPs in D. magna is of relevance.Dissolution of the exposed biological material prior to measurement by asymmetric flow field flow fractionation coupled to inductively coupled plasma mass spectrometry (AF4-ICPMS) is challenging because the ENPs must stay stable regarding to particle size and composition. Next to dissolution of exposed D. magna by tetra methyl ammonium hydroxide (TMAH), a new enzymatic dissolution approach was explored by using trypsin.The presence of various sized and composed ENPs has been confirmed by AF4-ICPMS but the chosen dissolution medium was crucial for the results. TMAH and trypsin led to comparable results for medium-sized (50nm) noble metals ENPs in exposed D. magna. But it was also shown that the dissolution of biological materials with smaller (<5nm) ENPs led to different results in particle size and elemental concentration depending on the selected dissolution medium. A significant uptake of Au and Pt ENPs by D. magna or adsorption to particles occurred because only 1–5% of the exposed ENPs remained in the exposure medium.

Growth inhibition of bloom forming cyanobacterium Microcystis aeruginosa by green route fabricated copper oxide nanoparticles.

The cyanobacterium Microcystis aeruginosa can potentially proliferate in a wide range of freshwater bionetworks and create extensive secondary metabolites which are harmful to human and animal health. The M. aeruginosa release toxic microcystins that can create a wide range of health-related issues to aquatic animals and humans. It is essential to eliminate them from the ecosystem with convenient method. It has been reported that engineered metal nanoparticles are potentially toxic to pathogenic organisms. In the present study, we examined the growth inhibition effect of green synthesized copper oxide nanoparticles against M. aeruginosa. The green synthesized copper oxide nanoparticles exhibit an excitation of surface plasmon resonance (SPR) at 270 nm confirmed using UV-visible spectrophotometer. The dynamic light scattering (DLS) analysis revealed that synthesized nanoparticles are colloidal in nature and having a particle size of 551 nm with high stability at -26.6 mV. The scanning electron microscopy (SEM) analysis shows that copper oxide nanoparticles are spherical, rod and irregular in shape, and consistently distributed throughout the solution. The elemental copper and oxide peak were confirmed using energy dispersive x-ray analysis (EDAX). Fourier-transform infrared (FT-IR) spectroscopy indicates the presence of functional groups which is mandatory for the reduction of copper ions. Besides, green synthesized copper oxide nanoparticles shows growth inhibition against M. aeruginosa. The inhibition efficiency was 31.8 % at lower concentration and 89.7 % at higher concentration of copper oxide nanoparticles, respectively. The chlorophyll (a and b) and carotenoid content of M. aeruginosa declined in dose-dependent manner with respect to induction of copper oxide nanoparticles. Furthermore, we analyzed the mechanism behind the cytotoxicity of M. aeruginosa induced by copper oxide nanoparticles through evaluating membrane integrity, reactive oxygen species (ROS), and mitochondrial membrane potential (Δψm) level. The results expose that there is a loss in membrane integrity with ROS formation that leads to alteration in the Δψm, which ends up with severe mitochondrial injury in copper oxide nanoparticles treated cells. Hence, green way synthesized copper oxide nanoparticles may be a useful selective biological agent for the control of M. aeruginosa.

Effects, Uptake, and Depuration Kinetics of Silver Oxide and Copper Oxide Nanoparticles in a Marine Deposit Feeder, Macoma balthica

Ag and CuO engineered nanoparticles (ENPs) have wide applications in industry and commercial products and may be released from wastewater into the aquatic environment. Limited information is currently available on metal ENP effects, uptake, and depuration kinetics in aquatic organisms. In the present study, a deposit-feeding clam, Macoma balthica, was exposed to sediment spiked with Ag and Cu in different forms (aqueous ions, nanoparticles, and micrometer-sized particles) in three experiments. In all experiments, no effects on mortality, condition index, or burrowing behavior were observed for any of the metal forms at measured sediment concentrations (150–200 μg/g) during 35 d of exposure. No genotoxicity was observed following exposure, measured as DNA damage with the single-cell gel electrophoresis assay (comet assay). Bioaccumulation of both Ag and Cu in the clams was form dependent such that bioaccumulation from sediment spiked with aqueous ions > nanoparticles > micrometer-sized particles. Cu uptake...