WorldWideScience

Sample records for carbon nanoparticle exposure

  1. Assessment of carbon nanoparticle exposure on murine macrophage function

    Science.gov (United States)

    Suro-Maldonado, Raquel M.

    There is growing concern about the potential cytotoxicity of nanoparticles. Exposure to respirable ultrafine particles (2.5uM) can adversely affect human health and have been implicated with episodes of increased respiratory diseases such as asthma and allergies. Nanoparticles are of particular interest because of their ability to penetrate into the lung and potentially elicit health effects triggering immune responses. Nanoparticles are structures and devises with length scales in the 1 to 100-nanometer range. Black carbon (BC) nanoparticles have been observed to be products of combustion, especially flame combustion and multi-walled carbon nanotubes (MWCNT) have been shown to be found in both indoor and outdoor air. Furthermore, asbestos, which have been known to cause mesothelioma as well as lung cancer, have been shown to be structurally identical to MWCNTs. The aims of these studies were to examine the effects of carbon nanoparticles on murine macrophage function and clearance mechanisms. Macrophages are immune cells that function as the first line of defense against invading pathogens and are likely to be amongst the first cells affected by nanoparticles. Our research focused on two manufactured nanoparticles, MWCNT and BC. The two were tested against murine-derived macrophages in a chronic contact model. We hypothesized that long-term chronic exposure to carbon nanoparticles would decrease macrophages ability to effectively respond to immunological challenge. Production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), cell surface macrophage; activation markers, reactive oxygen species formation (ROS), and antigen processing and presentation were examined in response to lipopolysaccharide (LPS) following a 144hr exposure to the particulates. Data demonstrated an increase in TNF-alpha, and NO production; a decrease in phagocytosis and antigen processing and presentation; and a decrease in the expression levels of cell surface macrophage

  2. Characterization of Potential Exposures to Nanoparticles and Fibers during Manufacturing and Recycling of Carbon Nanotube Reinforced Polypropylene Composites.

    Science.gov (United States)

    Boonruksa, Pongsit; Bello, Dhimiter; Zhang, Jinde; Isaacs, Jacqueline A; Mead, Joey L; Woskie, Susan R

    2016-01-01

    Carbon nanotube (CNT) polymer composites are widely used as raw materials in multiple industries because of their excellent properties. This expansion, however, is accompanied by realistic concerns over potential release of CNTs and associated nanoparticles during the manufacturing, recycling, use, and disposal of CNT composite products. Such data continue to be limited, especially with regards to post-processing of CNT-enabled products, recycling and handling of nanowaste, and end-of-life disposal. This study investigated for the first time airborne nanoparticle and fibers exposures during injection molding and recycling of CNT polypropylene composites (CNT-PP) relative to that of PP. Exposure characterization focused on source emissions during loading, melting, molding, grinding, and recycling of scrap material over 20 cycles and included real-time characterization of total particle number concentration and size distribution, nanoparticle and fiber morphology, and fiber concentrations near the operator. Total airborne nanoparticle concentration emitted during loading, melting, molding, and grinding of CNT-PP had geometric mean ranging from 1.2 × 10(3) to 4.3 × 10(5) particles cm(-3), with the highest exposures being up to 2.9 and 300.7 times above the background for injection molding and grinding, respectively. Most of these emissions were similar to PP synthesis. Melting and molding of CNT-PP and PP produced exclusively nanoparticles. Grinding of CNT-PP but not PP generated larger particles with encapsulated CNTs, particles with CNT extrusions, and respirable fiber (up to 0.2 fibers cm(-3)). No free CNTs were found in any of the processes. The number of recycling runs had no significant impact on exposures. Further research into the chemical composition of the emitted nanoparticles is warranted. In the meanwhile, exposure controls should be instituted during processing and recycling of CNT-PP. PMID:26447230

  3. Carbon black nanoparticle exposure during middle and late fetal development induces immune activation in male offspring mice

    International Nuclear Information System (INIS)

    Increasing exposure to nanoparticles (NPs) has raised concerns regarding their health and safety profiles in humans and animals, especially in developing organisms, which may display increased sensitivity to NP toxicity. The present study examined the effects of gestational exposure to carbon black NP (CB-NP) on the development of the offspring immune system. Pregnant mice were exposed to CB-NP (95 μg/kg body weight) by intranasal instillation on gestational days 9 and 15. The thymus and spleen were collected from their offspring mice on postnatal day (PND) 1, 3 and 5. Thymocyte and splenocyte phenotypes were examined by determining the expression of cell-surface molecules using flow cytometry. Gene expression in the thymus and spleen was examined using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Prenatal exposure to CB-NP increased total thymocytes and their immunophenotypes (CD4−CD8− and CD4+CD8+ cells). It also induced an increase in total lymphocytes, and CD4−CD8−, particularly CD3−B220−cells, at PND 5 in the spleen of newborn male offspring, reflecting the stimulation of immature splenocytes. Furthermore, mRNA expression of genes related to the induction of peripheral tolerance (i.e. thymic Traf6) was upregulated. These data suggest that respiratory exposure to CB-NP during middle and late gestation may have allergic or inflammatory effects in male offspring, and may provide initial information on the potential developmental immunotoxicity of nanoparticles

  4. Toxicological consequences of TiO2, SiC nanoparticles and multi-walled carbon nanotubes exposure in several mammalian cell types: an in vitro study

    International Nuclear Information System (INIS)

    The development of nanotechnologies may lead to dissemination of potentially toxic nanoparticles in the environment. Toxicology of these nano-sized particles is thus attracting attention of public and governments worldwide. Our research is focused on the in vitro response of eukaryotic cells to nanoparticles exposure. For this purpose, we used cellular models of primary target organs (lung: A549 alveolar epithelial cells), or secondary target organs (liver: WIF-B9, Can-10 and kidneys: NRK-52E, LLC-PK1 proximal cells), i.e., organs exposed if nanoparticles are translocated through epithelial barriers. These cells were exposed to TiO2, SiC nanoparticles or multi-walled carbon nanotubes (MWCNT). The influence of nanoparticles physico-chemical characteristics on various toxicological endpoints (cytotoxicity, reactive oxygen species generation, genotoxicity) was specified. Our data demonstrate that nanoparticles toxicity depend on their size, morphology, and chemical composition, the finest, spherical shaped, and anatase TiO2 nanoparticles being the more cytotoxic to NRK-52E cells, while SiC nanoparticles exert almost no cytotoxicity. MWCNT cytotoxicity neither depended on their length, nor on the presence of metal impurities. Nanoparticles cytotoxicity also depended on the exposed cell line. All the tested nanoparticles were uptaken by cells and caused intracellular reactive oxygen species generation. Relative to genotoxic effects, DNA strand breaks were detected in NRK-52E cells via the alkaline comet assay after exposure of cells to TiO2 nanoparticles and to a lesser extent after exposure to MWCNT, but no double strand breaks were detected. The originality of this study lies on the panel of nanomaterials which were tested on a variety of cell lines. All these data may lead to a better understanding of nanomaterial toxicity and hazards for health.

  5. Effect of combined nitrogen dioxide and carbon nanoparticle exposure on lung function during ovalbumin sensitization in Brown Norway rat.

    Directory of Open Access Journals (Sweden)

    Skander Layachi

    Full Text Available The interaction of particulate and gaseous pollutants in their effects on the severity of allergic inflammation and airway responsiveness are not well understood. We assessed the effect of exposure to NO(2 in the presence or absence of repetitive treatment with carbon nanoparticle (CNP during allergen sensitization and challenges in Brown-Norway (BN rat, in order to assess their interactions on lung function and airway responses (AR to allergen and methacholine (MCH, end-expiratory lung volume (EELV, bronchoalveolar lavage fluid (BALF cellular content, serum and BALF cytokine levels and histological changes. Animals were divided into the following groups (n = 6: Control; CNP (Degussa-FW2: 13 nm, 0.5 mg/kg instilled intratracheally ×3 at 7-day intervals; OVA: ovalbumin-sensitised; OVA+CNP: both sensitized and exposed to CNP. Rats were divided into equal groups exposed either to air or to NO(2, 10 ppm, 6 h/d, 5d/wk for 4 weeks. Exposure to NO(2, significantly enhanced lung inflammation and airway reactivity, with a significantly larger effect in animals sensitized to allergen, which was related to a higher expression of TH1 and TH2-type cytokines. Conversely, exposure to NO(2 in animals undergoing repeated tracheal instillation of CNP alone, increased BALF neutrophilia and enhanced the expression of TH1 cytokines: TNF-α and IFN-γ, but did not show an additive effect on airway reactivity in comparison to NO(2 alone. The exposure to NO(2 combined with CNP treatment and allergen sensitization however, unexpectedly resulted in a significant decrease in both airway reactivity to allergen and to methacholine, and a reduction in TH2-type cytokines compared to allergen sensitization alone. EELV was significantly reduced with sensitization, CNP treatment or both. These data suggest an immunomodulatory effect of repeated tracheal instillation of CNP on the proinflammatory effects of NO(2 exposure in sensitized BN rat. Furthermore, our findings suggest

  6. Real-world carbon nanoparticle exposures induce brain and gonadal alterations in zebrafish (Danio rerio) as determined by biospectroscopy techniques

    OpenAIRE

    Li, Junyi; Ying, Guang-Guo; Jones, Kevin C.; Martin, Francis L.

    2015-01-01

    Carbon-based nanoparticles (CNPs) have emerged as novel man-made materials with diverse applications, which may present significant risks to organisms. To bridge the gap in our knowledge of nano-toxicology, a number of in vitro or in vivo studies have been carried out. However, toxicity data remains limited. Herein, we employed a biospectroscopy approach to assess CNP-induced effects in zebrafish (Danio rerio). Zebrafish were exposed to Fullerene (C60), long or short multi-walled carbon nanot...

  7. Effects of prenatal exposure to nanoparticles titanium dioxide and carbon black on female germline DNA stability

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner

    Particulate air pollution has been associated with an increased risk of cardiovascular disease and cancer in humans. Air pollution may also adversely affect pregnancy outcome and the integrity of sperm cells DNA. Animal studies have shown that inhalation of air particulates can induce mutations in...... needed. Expanded simple tandem repeat (ESTR) loci in mice are sensitive markers of mutagenic effects resulting from environmental exposures; Studies on adult mice have revealed that while particulate air pollution induced ESTR mutations in premeiotic sperm cells, the female germline was not affected....... Unlike sperm cells that are continuously developed in adulthood, the majority of oocytes are in a dormant state during long periods of adult life and may therefore be less sensitive to mutations. However, female germ cells may be vulnerable during pregnancy when the female germ cells of the fetus when...

  8. Exposure to Nanoparticles and Hormesis

    OpenAIRE

    Iavicoli, Ivo; Calabrese, Edward J.; Nascarella, Marc A.

    2010-01-01

    Nanoparticles are particles with lengths that range from 1 to 100 nm. They are increasingly being manufactured and used for commercial purpose because of their novel and unique physicochemical properties. Although nanotechnology-based products are generally thought to be at a pre-competitive stage, an increasing number of products and materials are becoming commercially available. Human exposure to nanoparticles is therefore inevitable as they become more widely used and, as a result, nanotox...

  9. DNA Damage Following Pulmonary Exposure by Instillation to Low Doses of Carbon Black (Printex 90) Nanoparticles in Mice

    DEFF Research Database (Denmark)

    Kyjovska, Zdenka O.; Jacobsen, Nicklas R.; Saber, Anne T.;

    2015-01-01

    for the genotoxic effects of carbon black. In this study, we investigated inflammatory and acute phase response in addition to genotoxic effects occurring following exposure to nanoparticulate carbon black (NPCB) at even lower doses. C57BL/6JBomTac mice were examined 1, 3, and 28 days after a single...... instillation of 0.67, 2, 6, and 162 mu g Printex 90 NPCB and vehicle. Cellular composition and protein concentration was evaluated in BAL fluid as markers of inflammatory response and cell damage. DNA strand breaks in BAL cells, lung, and liver tissue were assessed using the alkaline comet assay. The pulmonary...... acute phase response was analyzed by Saa3 mRNA real-time quantitative PCR. Instillation of the low doses of NPCB induced a slight neutrophil influx one day after exposure. Pulmonary exposure to small doses of NPCB caused an increase in DNA strand breaks in BAL cells and lung tissue measured using the...

  10. Challenges and Perspectives of Nanoparticle Exposure Assessment

    OpenAIRE

    Lee, Ji Hyun; Moon, Min Chaul; Lee, Joon Yeob; Yu, Il Je

    2010-01-01

    Nanoparticle exposure assessment presents a unique challenge in the field of occupational and environmental health. With the commercialization of nanotechnology, exposure usually starts from the workplace and then spreads to environment and consumer exposure. This report discusses the current trends of nanoparticle exposure assessment, including the definition of nanotechnology relevant terms, essential physicochemical properties for nanomaterial characterization, current international activi...

  11. Titanium dioxide nanoparticles: Occupational exposure limits

    OpenAIRE

    Anna Maria Świdwińska-Gajewska; Sławomir Czerczak

    2014-01-01

    Titanium dioxide (TiO2) is produced in Poland as a high production volume chemical (HPVC). It is used mainly as a pigment for paints and coatings, plastics, paper, and also as additives to food and pharmaceuticals. Titanium dioxide nanoparticles are increasingly applied in cosmetics, textiles and plastics as the ultraviolet light blocker. This contributes to a growing occupational exposure to TiO2 nanoparticles. Nanoparticles are potentially responsible for the most adverse effects of titaniu...

  12. Pathway focused protein profiling indicates differential function for IL-1B, -18 and VEGF during initiation and resolution of lung inflammation evoked by carbon nanoparticle exposure in mice

    Directory of Open Access Journals (Sweden)

    Hamelmann Eckard

    2009-12-01

    Full Text Available Abstract Background Carbonaceous nanoparticles possess an emerging source of human exposure due to the massive release of combustion products and the ongoing revolution in nanotechnology. Pulmonary inflammation caused by deposited nanoparticles is central for their adverse health effects. Epidemiological studies suggest that individuals with favourable lung physiology are at lower risk for particulate matter associated respiratory diseases probably due to efficient control of inflammation and repair process. Therefore we selected a mouse strain C3H/HeJ (C3 with robust lung physiology and exposed it to moderately toxic carbon nanoparticles (CNP to study the elicited pulmonary inflammation and its resolution. Methods 5 μg, 20 μg and 50 μg CNP were intratracheally (i.t. instilled in C3 mice to identify the optimal dose for subsequent time course studies. Pulmonary inflammation was assessed using histology, bronchoalveolar lavage (BAL analysis and by a panel of 62 protein markers. Results 1 day after instillation of CNP, C3 mice exhibited a typical dose response, with the lowest dose (5 μg representing the 'no effect level' as reflected by polymorphonuclear leucocyte (PMN, and BAL/lung concentrations of pro-inflammatory proteins. Histological analysis and BAL-protein concentration did not reveal any evidence of tissue injury in 20 μg CNP instilled animals. Accordingly time course assessment of the inflammatory response was performed after 3 and 7 days with this dose (20 μg. Compared to day 1, BAL PMN counts were significantly decreased at day 3 and completely returned to normal by day 7. We have identified protein markers related to the acute response and also to the time dependent response in lung and BAL. After complete resolution of PMN influx on day 7, we detected elevated concentrations of 20 markers that included IL1B, IL18, FGF2, EDN1, and VEGF in lung and/or BAL. Biological pathway analysis revealed these factors to be involved in a

  13. Prenatal Exposure to Carbon Black (Printex 90)

    DEFF Research Database (Denmark)

    Jackson, Petra; Vogel, Ulla; Wallin, Håkan;

    2011-01-01

    Maternal pulmonary exposure to ultrafine particles during pregnancy may affect the health of the child. Developmental toxicity of carbon black (Printex 90) nanoparticles was evaluated in a mouse model. Time-mated mice were intratracheally instilled with Printex 90 dispersed in Millipore water on...... gestation days (GD) 7, 10, 15 and 18, with total doses of 11, 54 and 268 mu g Printex 90/animal. The female offspring prenatally exposed to 268 mu g Printex 90/animal displayed altered habituation pattern during the Open field test....

  14. SYNTHESIS AND CHARACTERIZATION OF COPPER CARBONATE NANOPARTICLES

    OpenAIRE

    R.Hepzi Pramila Devamani; Sabeena, M.

    2014-01-01

    Copper carbonate nanoparticles were synthesized via chemical co-precipitation method from copper sulphate and sodium carbonate. The formed nanoparticle is characterized by powder x-ray diffraction, scanning electron microscopy, ultra-violet spectroscopy and fourier transform infrared spectroscopy, confirmed the preferential growth of copper carbonate nanoparticles that width is 90.55nm. The SEM image shows the synthesized copper carbonate show well crystallized particles with ...

  15. SYNTHESIS AND CHARACTERIZATION OF COPPER CARBONATE NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    R.Hepzi Pramila Devamani

    2014-04-01

    Full Text Available Copper carbonate nanoparticles were synthesized via chemical co-precipitation method from copper sulphate and sodium carbonate. The formed nanoparticle is characterized by powder x-ray diffraction, scanning electron microscopy, ultra-violet spectroscopy and fourier transform infrared spectroscopy, confirmed the preferential growth of copper carbonate nanoparticles that width is 90.55nm. The SEM image shows the synthesized copper carbonate show well crystallized particles with spherical morphology. The FTIR spectrum is used to study the stretching and bending frequencies of molecular functional groups in the sample. From UV spectrum, the band gap of copper carbonate nanoparticles is found to be 3.4eV.

  16. Probing carbon coatings on nanoparticle decorated carbon nanotubes by scanning transmission X-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ming; Gao, Jing; Bai, Lili; Pu, Aiwu; Liu, Jinyin; Zhao, Guanqi; Sun, Xuhui; Zhong, Jun, E-mail: jzhong@suda.edu.cn

    2013-11-15

    Two kinds of carbon coating on carbon nanotubes (CNTs) after decoration with nanoparticles were observed by scanning transmission X-ray microscopy with a concurrent characterization of the electronic structure, revealing the complex compositions in CNTs after chemical modification. Moreover, a sandwich structure shown as CNT-nanoparticle-coating can be created with the exposure to X-ray for CNTs decorated with nanoparticle outside the wall. The coating shows an effective way for site-selective modification of CNTs with various carbon structures.

  17. Titanium dioxide nanoparticles: Occupational exposure limits

    Directory of Open Access Journals (Sweden)

    Anna Maria Świdwińska-Gajewska

    2014-06-01

    Full Text Available Titanium dioxide (TiO2 is produced in Poland as a high production volume chemical (HPVC. It is used mainly as a pigment for paints and coatings, plastics, paper, and also as additives to food and pharmaceuticals. Titanium dioxide nanoparticles are increasingly applied in cosmetics, textiles and plastics as the ultraviolet light blocker. This contributes to a growing occupational exposure to TiO2 nanoparticles. Nanoparticles are potentially responsible for the most adverse effects of titanium dioxide. Due to the absence of separate fraction of nanoobjects and appropriate measurement methods the maximum admissible concentrations (MAC for particles < 100 nm and nano-TiO2 cannot be established. In the world there are 2 proposals of occupational exposure levels for titanium dioxide nanoparticles: 0.3 mg/m3, proposed by the National Institute for Occupational Safety and Health (NIOSH, and 0.6 mg/m3, proposed by experts of the New Energy and Industrial Technology Development Organization (NEDO. The authors of this article, based on the available data and existing methods for hygiene standards binding in Poland, concluded that the MAC value of 0.3 mg/m3 for nanoparticles TiO2 in the workplace air can be accepted. Med Pr 2014;65(3:407–418

  18. Whole-body nanoparticle aerosol inhalation exposures.

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L; Stapleton, Phoebe A; Minarchick, Valerie C; Nurkiewicz, Timothy R

    2013-01-01

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size (6), which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria (5). A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m(3) whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm(3)) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m(3)). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpre and Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is sampling flowrate (m(3)/min), and t is the sampling

  19. Whole-Body Nanoparticle Aerosol Inhalation Exposures

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T.; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L.; Stapleton, Phoebe A.; Minarchick, Valerie C.; Nurkiewicz, Timothy R.

    2013-01-01

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter < 200 nm and a geometric standard deviation σg < 2.5 5. The generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size 6, which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria 5. A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m3 whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm3) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m3). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpreand Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is

  20. DSC Study on Polypropylene Modified with Calcium Carbonate Nanoparticles

    International Nuclear Information System (INIS)

    The exposure of polypropylene containing various concentrations of calcium carbonate nanoparticles was performed in air and water. The radiolysis products of water determine different behaviour of polymer substrate. The irradiation effect induced on polymer and the contribution of nanoparticles to the scavenging of oxygenated products that were created during γ exposure were investigated by DSC measurements over the temperature range from 340-400 K, the usual temperatures for thermal overcharge. Two kinds of carbonate particles, one type is represented by unmodified filler, while the second type is the superficially modified with stearic acid. The covering of particle surface with stearic acid confers to them a different ability in the abstraction of degradation products formed in irradiated isotactic polypropylene

  1. Magnetic Carbon Nanotubes Tethered with Maghemite Nanoparticles

    Science.gov (United States)

    Kim, Il Tae; Nunnery, Grady; Jacob, Karl; Schwartz, Justin; Liu, Xiaotao; Tannenbaum, Rina

    2011-03-01

    We describe a novel, facile method for the synthesis of magnetic carbon nanotubes (m-CNTs) decorated with monodisperse γ - Fe 2 O3 magnetic (maghemite) nanoparticles and their aligned feature in a magnetic field. The tethering of the nanoparticles was achieved by the initial activation of the surface of the CNTs with carboxylic acid groups, followed by the attachment of the γ - Fe 2 O3 nanoparticles via a modified sol-gel process. Sodium dodecylbenzene sulfonate (NaDDBS) was introduced into the suspension to prevent the formation of an iron oxide 3D network. Various characterization methods were used to confirm the formation of well-defined maghemite nanoparticles. The tethered nanoparticles imparted magnetic characteristics to the CNTs, which became superparamagnetic. The m-CNTs were oriented parallel to the direction of a magnetic field. This has the potential of enhancing various properties, e.g. mechanical and electrical properties, in composite materials.

  2. Antimicrobial Activity of Carbon-Based Nanoparticles

    Directory of Open Access Journals (Sweden)

    Solmaz Maleki Dizaj

    2015-03-01

    Full Text Available Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs (especially single-walled carbon nanotubes (SWCNTs and graphene oxide (GO nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery.

  3. Assay of carbon nanoparticles in liquids.

    Science.gov (United States)

    Nawi, Yehuda; Sasson, Yoel; Dolgin, Bella

    2016-04-01

    The critical assay of carbon black concentration suffers from the lack of available methods, especially in-situ methods suitable for nanoparticles. We propose a useful tool for monitoring carbon nanoparticles concentration in liquids by means of RGB imaging, fluorescence and conductivity measurements. In this study carbon black particles of 25-75nm size were dispersed within two types of "green" liquids (1-butyl-3-methyl imidazolium based ionic liquids and glycerol) and the effect of carbon nanoparticles concentration on the liquids properties was measured. The conductivity of all the liquids increased with carbon concentration, while the slope of the curve was liquid dependent. The fluorescence intensity of ionic liquids decreased dramatically even when a small amount of carbon was added, while water-containing ionic liquids had a more moderate behavior. Glycerol has no native fluorescence, therefore, a known tracer present in soot (dibenzothiophene), having a characteristic fluorescence monitored by synchronous scan mode, was used. The carbon black effect on RGB imaging shows a linear dependence, while the red counts decreases with contamination. The proposed methods are simple and low-cost but nonetheless sensitive. PMID:26780588

  4. Influence of an Electron Beam Exposure on the Surface Plasmon Resonance of Gold Nanoparticles

    OpenAIRE

    Song, M; des Francs, G. Colas; Bouhelier, A.

    2014-01-01

    Electron beam imaging is a common technique used for characterizing the morphology of plasmonic nanostructures. During the imaging process, the electron beam interacts with traces of organic material in the chamber and produces a well-know layer of amorphous carbon over the specimen under investigation. In this paper, we investigate the effect of this carbon adsorbate on the spectral position of the surface plasmon in individual gold nanoparticles as a function of electron exposure dose. We f...

  5. Oral exposure to polystyrene nanoparticles affects iron absorption

    Science.gov (United States)

    Mahler, Gretchen J.; Esch, Mandy B.; Tako, Elad; Southard, Teresa L.; Archer, Shivaun D.; Glahn, Raymond P.; Shuler, Michael L.

    2012-04-01

    The use of engineered nanoparticles in food and pharmaceuticals is expected to increase, but the impact of chronic oral exposure to nanoparticles on human health remains unknown. Here, we show that chronic and acute oral exposure to polystyrene nanoparticles can influence iron uptake and iron transport in an in vitro model of the intestinal epithelium and an in vivo chicken intestinal loop model. Intestinal cells that are exposed to high doses of nanoparticles showed increased iron transport due to nanoparticle disruption of the cell membrane. Chickens acutely exposed to carboxylated particles (50 nm in diameter) had a lower iron absorption than unexposed or chronically exposed birds. Chronic exposure caused remodelling of the intestinal villi, which increased the surface area available for iron absorption. The agreement between the in vitro and in vivo results suggests that our in vitro intestinal epithelium model is potentially useful for toxicology studies.

  6. POROUS STRUCTURE OF CARBON NANOPARTICLES PREPARED BY CHLORINATION OF NANOPARTICLES OF SILICON CARBID

    OpenAIRE

    Sokolov, V. V.; PETROV N.A.; TOMKOVICH M.V.; GUSAROV V. V.

    2014-01-01

    Specific features of the structure of nanoporous carbon, prepared by chlorinating silicon carbide nanoparticles followed by treatment thereof by hydrogenation have been studied. A considerable number of microscopic pores in carbon nanoparticles have been shown.

  7. Human Exposure Assessment of Engineered Inorganic Nanoparticles in Food

    OpenAIRE

    Fabricius, Lars

    2011-01-01

    An increasingly important part of food technology is nanotechnology. Inorganic nanoparticles are added directly or indirectly to food in order to create new tastes, appetizing looks or to preserve it longer. Exposure to these nanoparticles is fairly unknown, and there is a need to evaluate the dose that humans are exposed to. In this master thesis, two inorganic substances have been chosen. The first one is silver nanoparticles, commonly known as an antimicrobial agent and added to plastic fo...

  8. Attachment of Gold Nanoparticles to Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Xi Cheng MA; Ning LUN; Shu Lin WEN

    2005-01-01

    Carbon nanotubes were initially chemically modified with an H2SO4-HNO3 treatment,and subsequently activated with Pd-Sn catalytic nuclei via a one-step activation approach. These activated nanotubes were used as precursors for obtaining gold nanoparticles-attached nanotubes via simple electroless plating. This approach provides an efficient method for attachment of metal nanostructures to carbon nanotubes. Such novel hybrid nanostructures are attractive for many applications.

  9. Task-based exposure assessment of nanoparticles in the workplace

    International Nuclear Information System (INIS)

    Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

  10. Temperature driven transport of gold nanoparticles physisorbed inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, P.A.E.; Poulikakos, D.; Walther, Jens Honore; Koumoutsakos, P.

    2006-01-01

    We use molecular dynamics simulations to demonstrate the temperature driven mass transport of solid gold nanoparticles, physisorbed inside carbon nanotubes (CNTs). Our results indicate that the nanoparticle experiences a guided motion, in the direction opposite to the direction of the temperature...... affects the nanoparticle motion along the carbon lattice....

  11. DNA binding and aggregation by carbon nanoparticles

    International Nuclear Information System (INIS)

    Significant environmental and health risks due to the increasing applications of engineered nanoparticles in medical and industrial activities have been concerned by many communities. The interactions between nanomaterials and genomes have been poorly studied so far. This study examined interactions of DNA with carbon nanoparticles (CNP) using atomic force microscopy (AFM). We experimentally assessed how CNP affect DNA molecule and bacterial growth of Escherichia coli. We found that CNP were bound to the DNA molecules during the DNA replication in vivo. The results revealed that the interaction of DNA with CNP resulted in DNA molecule binding and aggregation both in vivo and in vitro in a dose-dependent manner, and consequently inhabiting the E. coli growth. While this was a preliminary study, our results showed that this nanoparticle may have a significant impact on genomic activities.

  12. Controlled Synthesis of Carbon Nanoparticles in a Supercritical Carbon Disulfide System

    Directory of Open Access Journals (Sweden)

    Zhengsong Lou

    2013-12-01

    Full Text Available Carbon nanoparticles with large surface areas were produced by the reduction of carbon disulfide with metallic lithium at 500 °C. The carbon nanoparticles account for about 80% of the carbon product. The carbon nanoparticles were characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and N2 physisorption. The results showed that carbon nanoparticles predominate in the product. The influence of experimental conditions was investigated, which indicated that temperature plays a crucial role in the formation of carbon nanoparticles. The possible formation mechanism of the carbon nanoparticles was discussed. This method provides a simple and efficient route to the synthesis of carbon nanoparticles.

  13. Epoxy based photoresist/carbon nanoparticle composites

    DEFF Research Database (Denmark)

    Lillemose, Michael; Gammelgaard, Lauge; Richter, Jacob;

    2008-01-01

    We have fabricated composites of SU-8 polymer and three different types of carbon nanoparticles (NPs) using ultrasonic mixing. Structures of composite thin films have been patterned on a characterization chip with standard UV photolithography. Using a four-point bending probe, a well defined stress...... is applied to the composite thin film and we have demonstrated that the composites are piezoresistive. Stable gauge factors of 5-9 have been measured, but we have also observed piezoresistive responses with gauge factors as high as 50. As SU-8 is much softer than silicon and the gauge factor of the...... composite material is relatively high, carbon nanoparticle doped SU-8 is a valid candidate for the piezoresistive readout in polymer based cantilever sensors, with potentially higher sensitivity than silicon based cantilevers....

  14. Nanoparticle tracers in calcium carbonate porous media

    KAUST Repository

    Li, Yan Vivian

    2014-07-15

    Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention. © 2014 Springer Science+Business Media.

  15. Synthesis of photoluminescent carbon nanoparticles from graphite

    Energy Technology Data Exchange (ETDEWEB)

    Fu Xiaobo; Li Dianhong; Zhang Yuanming, E-mail: tzhangymjnu@163.com [School of Life Science and Technology, Jinan University, Department of Chemistry (China)

    2013-04-15

    Photoluminescent carbon nanoparticles (CNPs) with diameters ranging from 1.5 to 6.5 nm were synthesized from raw graphite without surface passivation. The photoluminescent (PL) emission spectra illustrate that both excitation wavelength and solution pH can significantly influence the maximum emission wavelength and PL intensity of the CNP solution. As the excitation wavelength decreases and solution pH increases, a blue shift in the maximum PL emission wavelength occurs.

  16. Synthesis of photoluminescent carbon nanoparticles from graphite

    International Nuclear Information System (INIS)

    Photoluminescent carbon nanoparticles (CNPs) with diameters ranging from 1.5 to 6.5 nm were synthesized from raw graphite without surface passivation. The photoluminescent (PL) emission spectra illustrate that both excitation wavelength and solution pH can significantly influence the maximum emission wavelength and PL intensity of the CNP solution. As the excitation wavelength decreases and solution pH increases, a blue shift in the maximum PL emission wavelength occurs.

  17. Phonon assisted thermophoretic motion of gold nanoparticles inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, Philipp A.E.; Walther, Jens Honore; Poulikakos, Dimos;

    2007-01-01

    The authors investigate the thermally driven mass transport of gold nanoparticles confined inside carbon nanotubes using molecular dynamics simulations. The observed thermophoretic motion of the gold nanoparticles correlates with the phonon dispersion exhibited by a standard carbon nanotube and, in...... particular, with the breathing mode of the tube. Additionally, the results show an increased static friction for gold nanoparticles confines inside a zig-zag carbon nanotube when increasing the size length of the nanoparticles. However, an unexpected, opposite trend is observed for the same nanoparticles...

  18. Carbon encapsulated magnetic nanoparticles produced by hydrothermal reaction

    Institute of Scientific and Technical Information of China (English)

    Nong Yue He; Ya Fei Guo; Yan Deng; Zhi Fei Wang; Song Li; Hong Na Liu

    2007-01-01

    Carbon encapsulated magnetic nanoparticles (CEMNs) were synthesized by heating an aqueous glucose solution containing FeAu (Au coated Fe nanoparticles) nanoparticles at 160-180 ℃ for 2 h. This novel hydrothermal approach is not only simple but also provides the surface of CEMNs with functional groups like-OH. The formation of carbon encapsulated magnetic nanoparticles was not favored when using pure Fe nanoparticles as cores because of the oxidation of Fe nanoparticles by H2O during the reaction and,therefore, the surfaces of the naked Fe nanoparticles had to be coated by Au shell in advance. TEM, XRD, XPS and VSM measurments characterized that they were uniform carbon spheres containing some embedded Fe-Au nanoparticles, with a saturation of 14.6 emu/g and the size of the typical product is ~350 nm.

  19. Growth of carbon nanostructures on carbonized electrospun nanofibers with palladium nanoparticles

    International Nuclear Information System (INIS)

    This paper studies the mechanism of the formation of carbon nanostructures on carbon nanofibers with Pd nanoparticles by using different carbon sources. The carbon nanofibers with Pd nanoparticles were produced by carbonizing electrospun polyacrylonitrile (PAN) nanofibers including Pd(Ac)2. Such PAN-based carbon nanofibers were then used as substrates to grow hierarchical carbon nanostructures. Toluene, pyridine and chlorobenzine were employed as carbon sources for the carbon nanostructures. With the Pd nanoparticles embedded in the carbonized PAN nanofibers acting as catalysts, molecules of toluene, pyridine or chlorobenzine were decomposed into carbon species which were dissolved into the Pd nanoparticles and consequently grew into straight carbon nanotubes, Y-shaped carbon nanotubes or carbon nano-ribbons on the carbon nanofiber substrates. X-ray diffraction analysis and transmission electron microscopy (TEM) were utilized to capture the mechanism of formation of Pd nanoparticles, regular carbon nanotubes, Y-shaped carbon nanotubes and carbon nano-ribbons. It was observed that the Y-shaped carbon nanotubes and carbon nano-ribbons were formed on carbonized PAN nanofibers containing Pd-nanoparticle catalyst, and the carbon sources played a crucial role in the formation of different hierarchical carbon nanostructures

  20. Workplace exposure to nanoparticles from gas metal arc welding process

    International Nuclear Information System (INIS)

    Workplace exposure to nanoparticles from gas metal arc welding (GMAW) process in an automobile manufacturing factory was investigated using a combination of multiple metrics and a comparison with background particles. The number concentration (NC), lung-deposited surface area concentration (SAC), estimated SAC and mass concentration (MC) of nanoparticles produced from the GMAW process were significantly higher than those of background particles before welding (P < 0.01). A bimodal size distribution by mass for welding particles with two peak values (i.e., 10,000–18,000 and 560–320 nm) and a unimodal size distribution by number with 190.7-nm mode size or 154.9-nm geometric size were observed. Nanoparticles by number comprised 60.7 % of particles, whereas nanoparticles by mass only accounted for 18.2 % of the total particles. The morphology of welding particles was dominated by the formation of chain-like agglomerates of primary particles. The metal composition of these welding particles consisted primarily of Fe, Mn, and Zn. The size distribution, morphology, and elemental compositions of welding particles were significantly different from background particles. Working activities, sampling distances from the source, air velocity, engineering control measures, and background particles in working places had significant influences on concentrations of airborne nanoparticle. In addition, SAC showed a high correlation with NC and a relatively low correlation with MC. These findings indicate that the GMAW process is able to generate significant levels of nanoparticles. It is recommended that a combination of multiple metrics is measured as part of a well-designed sampling strategy for airborne nanoparticles. Key exposure factors, such as particle agglomeration/aggregation, background particles, working activities, temporal and spatial distributions of the particles, air velocity, engineering control measures, should be investigated when measuring workplace

  1. Impacts of Nickel Nanoparticles on Mineral Carbonation

    Directory of Open Access Journals (Sweden)

    Marius Bodor

    2014-01-01

    Full Text Available This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO2 and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO2 mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags, on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach more acidic pH values upon CO2 bubbling, confirming a higher quantity of bicarbonate ions. This effect resulted in acceleration of mineral carbonation in the first fifteen minutes of reaction time when NiNP was present. After this initial stage, however, no benefit of NiNP addition was seen, resulting in very similar carbonation extents after one hour of reaction time. It was also found that increasing solids content decreased the benefit of NiNP, even in the early stages. These results suggest that NiNP has little contribution to mineral carbonation processes when the dissolution of alkaline earth metals is rate limiting.

  2. Red Fluorescent Carbon Nanoparticle-Based Cell Imaging Probe.

    Science.gov (United States)

    Ali, Haydar; Bhunia, Susanta Kumar; Dalal, Chumki; Jana, Nikhil R

    2016-04-13

    Fluorescent carbon nanoparticle-based probes with tunable visible emission are biocompatible, environment friendly and most suitable for various biomedical applications. However, synthesis of red fluorescent carbon nanoparticles and their transformation into functional nanoparticles are very challenging. Here we report red fluorescent carbon nanoparticle-based nanobioconjugates of carbon nanoparticles are synthesized via high temperature colloid-chemical approach and transformed into water-soluble functional nanoparticles via coating with amphiphilic polymer followed by covalent linking with desired biomolecules. Following this approach, carbon nanoparticles are functionalized with polyethylene glycol, primary amine, glucose, arginine, histidine, biotin and folic acid. These functional nanoparticles can be excited with blue/green light (i.e., 400-550 nm) to capture their emission spanning from 550 to 750 nm. Arginine and folic acid functionalized nanoparticles have been demonstrated as fluorescent cell labels where blue and green excitation has been used for imaging of labeled cells. The presented method can be extended for the development of carbon nanoparticle-based other bioimaging probes. PMID:27011336

  3. Worker exposure to ultrafine particles during carbon black treatment

    Directory of Open Access Journals (Sweden)

    Urszula Mikołajczyk

    2015-07-01

    Full Text Available Background: The aim of the project was to assess the exposure of workers to ultrafine particles released during handling and packing of carbon black. The assessment included the results of the measurements performed in a carbon black handling plant before, during, and after work shift. Material and Methods: The number concentration of particles within the dimension range 10–1000 nm and 10–100 nm was assayed by a condensation particle counter (CPC. The mass concentration of particles was determined by a DustTrak II DRX aerosol concentration monitor. The surface area concentration of the particles potentially deposited in the alveolar (A and tracheo-bronchial (TB regions was estimated by an AeroTrak 9000 nanoparticle monitor. Results: An average mass concentration of particles during the process was 6-fold higher than that before its start, while a 3-fold increase in the average number concentration of particles within the dimension range 10–1000 nm and 10–100 nm was observed during the process. At the same time a 4-fold increase was found in the surface area concentration of the particles potentially deposited in the A and TB regions. Conclusions: During the process of carbon black handling and packing a significantly higher values of each of the analysed parameters, characterizing the exposure to ultrafine particles, were noted. Med Pr 2015;66(3:317–326

  4. Nickel Nanoparticles Exposure and Reproductive Toxicity in Healthy Adult Rats

    Directory of Open Access Journals (Sweden)

    Lu Kong

    2014-11-01

    Full Text Available Nickel is associated with reproductive toxicity. However, the reproductive toxicity of nickel nanoparticles (Ni NPs is unclear. Our goal was to determine the association between nickel nanoparticle exposure and reproductive toxicity. According to the one-generation reproductive toxicity standard, rats were exposed to nickel nanoparticles by gavage and we selected indicators including sex hormone levels, sperm motility, histopathology, and reproductive outcome etc. Experimental results showed nickel nanoparticles increased follicle stimulating hormone (FSH and luteinizing hormone (LH, and lowered etradiol (E2 serum levels at a dose of 15 and 45 mg/kg in female rats. Ovarian lymphocytosis, vascular dilatation and congestion, inflammatory cell infiltration, and increase in apoptotic cells were found in ovary tissues in exposure groups. For male rats, the weights decreased gradually, the ratio of epididymis weight over body weight increased, the motility of rat sperm changed, and the levels of FSH and testosterone (T diminished. Pathological results showed the shedding of epithelial cells of raw seminiferous tubule, disordered arrangement of cells in the tube, and the appearance of cell apoptosis and death in the exposure group. At the same time, Ni NPs resulted in a change of the reproductive index and the offspring development of rats. Further research is needed to elucidate exposure to human populations and mechanism of actions.

  5. Effective biological dose from occupational exposure during nanoparticle synthesis

    International Nuclear Information System (INIS)

    Nanomaterial and nanotechnology safety require the characterization of occupational exposure levels for completing a risk assessment. However, equally important is the estimation of the effective internal dose via lung deposition, transport and clearance mechanisms. An integrated source-to-biological dose assessment study is presented using real monitoring data collected during nanoparticle synthesis. Experimental monitoring data of airborne exposure levels during nanoparticle synthesis of CaSO4 and BiPO4 nanoparticles in a research laboratory is coupled with a human lung transport and deposition model, which solves in an Eulerian framework the general dynamic equation for polydisperse aerosols using particle specific physical-chemical properties. Subsequently, the lung deposition model is coupled with a mathematical particle clearance model providing the effective biological dose as well as the time course of the biological dose build-up after exposure. The results for the example of BiPO4 demonstrate that even short exposures throughout the day can lead to particle doses of 1.10·E+08/(kg-bw·8h-shift), with the majority accumulating in the pulmonary region. Clearance of particles is slow and is not completed within a working shift following a 1 hour exposure. It mostly occurs via macrophage activity in the alveolar region, with small amounts transported to the interstitium and less to the lymph nodes.

  6. Effective biological dose from occupational exposure during nanoparticle synthesis

    Science.gov (United States)

    Demou, Evangelia; Tran, Lang; Housiadas, Christos

    2009-02-01

    Nanomaterial and nanotechnology safety require the characterization of occupational exposure levels for completing a risk assessment. However, equally important is the estimation of the effective internal dose via lung deposition, transport and clearance mechanisms. An integrated source-to-biological dose assessment study is presented using real monitoring data collected during nanoparticle synthesis. Experimental monitoring data of airborne exposure levels during nanoparticle synthesis of CaSO4 and BiPO4 nanoparticles in a research laboratory is coupled with a human lung transport and deposition model, which solves in an Eulerian framework the general dynamic equation for polydisperse aerosols using particle specific physical-chemical properties. Subsequently, the lung deposition model is coupled with a mathematical particle clearance model providing the effective biological dose as well as the time course of the biological dose build-up after exposure. The results for the example of BiPO4 demonstrate that even short exposures throughout the day can lead to particle doses of 1.10·E+08#/(kg-bw·8h-shift), with the majority accumulating in the pulmonary region. Clearance of particles is slow and is not completed within a working shift following a 1 hour exposure. It mostly occurs via macrophage activity in the alveolar region, with small amounts transported to the interstitium and less to the lymph nodes.

  7. Hydrogen emission under laser exposure of colloidal solutions of nanoparticles

    CERN Document Server

    Barmina, E V; Shafeev, G A

    2016-01-01

    We report the generation of molecular hydrogen from water by laser irradiation, without any electrodes and photocatalysts. A near infrared pulsed nanosecond laser is used for exposure of colloidal solution of Au nanoparticles suspended in water. Laser exposure of the colloidal solution results in formation of plasma of laser breakdown of liquid and emission of H2. The rate of H2 emission depends critically on the energy of laser pulses. There is a certain threshold in laser fluence in liquid (around 50 J/cm2) below which plasma disappears and H2 emission stops. H2 emission from colloidal solution of Au nanoparticles in ethanol is higher than that from similar water colloid. It is found that formation of plasma and emission of H2 or D2 can be induced by laser exposure of pure liquids, either H2O or D2O, respectively. The results are interpreted as water molecules splitting by direct electron impact from breakdown plasma.

  8. Composite Materials with Magnetically Aligned Carbon Nanoparticles Having Enhanced Electrical Properties and Methods of Preparation

    Science.gov (United States)

    Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

    2016-01-01

    Magnetically aligned carbon nanoparticle composites have enhanced electrical properties. The composites comprise carbon nanoparticles, a host material, magnetically sensitive nanoparticles and a surfactant. In addition to enhanced electrical properties, the composites can have enhanced mechanical and thermal properties.

  9. Temperature driven transport of gold nanoparticles physisorbed inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, P.A.E.; Poulikakos, D.; Walther, Jens Honore;

    2006-01-01

    We use molecular dynamics simulations to demonstrate the temperature driven mass transport of solid gold nanoparticles, physisorbed inside carbon nanotubes (CNTs). Our results indicate that the nanoparticle experiences a guided motion, in the direction opposite to the direction of the temperature...... gradient applied to the carrier CNT. The force experienced by the nanoparticle is of thermophoretic character, scaling linearly with the applied temperature gradient. The present results prove that the surface corrugation of different types of CNTs and the magnitude of the temperature gradient strongly...... affects the nanoparticle motion along the carbon lattice....

  10. In vitro toxicological nanoparticle studies under flow exposure

    International Nuclear Information System (INIS)

    The use of nanoparticles is becoming increasingly common in industry and everyday objects. Thus, extensive risk management concerning the potential health risk of nanoparticles is important. Currently, in vitro nanoparticle testing is mainly performed under static culture conditions without any shear stress. However, shear stress is an important biomechanical parameter. Therefore, in this study, a defined physiological flow to different mammalian cell lines such as A549 cells and NIH-3T3 cells has been applied. The effects of zinc oxide and titanium dioxide nanoparticles (TiO2-NP), respectively, were investigated under both static and dynamic conditions. Cell viability, cell morphology, and adhesion were proven and compared to the static cell culture. Flow exposure had an impact on the cellular morphology of the cells. NIH-3T3 cells were elongated in the direction of flow and A549 cells exhibited vesicles inside the cells. Zinc oxide nanoparticles reduced the cell viability in the static and in the dynamic culture; however, the dynamic cultures were more sensitive. In the static culture and in the dynamic culture, TiO2-NP did not affect cell viability. In conclusion, dynamic culture conditions are important for further in vitro investigations and provide more relevant results than static culture conditions

  11. In vitro toxicological nanoparticle studies under flow exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sambale, Franziska, E-mail: sambale@iftc.uni-hannover.de; Stahl, Frank; Bahnemann, Detlef; Scheper, Thomas [Gottfried Wilhelm Leibniz University Hanover, Institute for Technical Chemistry (Germany)

    2015-07-15

    The use of nanoparticles is becoming increasingly common in industry and everyday objects. Thus, extensive risk management concerning the potential health risk of nanoparticles is important. Currently, in vitro nanoparticle testing is mainly performed under static culture conditions without any shear stress. However, shear stress is an important biomechanical parameter. Therefore, in this study, a defined physiological flow to different mammalian cell lines such as A549 cells and NIH-3T3 cells has been applied. The effects of zinc oxide and titanium dioxide nanoparticles (TiO{sub 2}-NP), respectively, were investigated under both static and dynamic conditions. Cell viability, cell morphology, and adhesion were proven and compared to the static cell culture. Flow exposure had an impact on the cellular morphology of the cells. NIH-3T3 cells were elongated in the direction of flow and A549 cells exhibited vesicles inside the cells. Zinc oxide nanoparticles reduced the cell viability in the static and in the dynamic culture; however, the dynamic cultures were more sensitive. In the static culture and in the dynamic culture, TiO{sub 2}-NP did not affect cell viability. In conclusion, dynamic culture conditions are important for further in vitro investigations and provide more relevant results than static culture conditions.

  12. Size Dependent Phase Diagrams of Nickel-Carbon Nanoparticles

    Science.gov (United States)

    Magnin, Y.; Zappelli, A.; Amara, H.; Ducastelle, F.; Bichara, C.

    2015-11-01

    The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nm (807 Ni atoms). A tight binding model for interatomic interactions drives the grand canonical Monte Carlo simulations used to locate solid, core shell and liquid stability domains, as a function of size, temperature, and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should lead to a better understanding of the nanotube growth mechanisms.

  13. Continuous 3-day exposure assessment of workplace manufacturing silver nanoparticles

    International Nuclear Information System (INIS)

    With the increased production and widespread use of nanomaterials, human and environmental exposure to nanomaterials is inevitably increasing. Therefore, this study monitored the possible nanoparticle exposure at a workplace that manufactures silver nanoparticles. To estimate the potential exposure of workers, personal sampling, area monitoring, and real-time monitoring were conducted over 3 days using a scanning mobility particle sizer and dust monitor at a workplace where the workers handle nanomaterials. The area sampling concentrations obtained from the injection room showed the highest concentration, ranging from 0.00501 to 0.28873 mg/m3. However, apart from the injection room, none of the area samplings obtained from other locations showed a concentration higher than 0.0013 mg/m3. Meanwhile, the personal sampling concentrations ranged from 0.00004 to 0.00243 mg/m3 over the 3 days of sampling, which was much lower than the silver TLV. The particle number concentrations at the silver nanoparticle manufacturing workplace were 911,170 (1st day), 1,631,230 (2nd day), and 1,265,024 (3rd day) particles/cm3 with a size range of 15–710.5 nm during the operation of the reactor, while the concentration decreased to 877,364.9 (1st day), 492,732 (2nd day), and 344,343 (3rd day) particles/cm3 when the reactor was stopped.

  14. Exposure modeling of engineered nanoparticles in the environment.

    Science.gov (United States)

    Mueller, Nicole C; Nowack, Bernd

    2008-06-15

    The aim of this study was to use a life-cycle perspective to model the quantities of engineered nanoparticles released into the environment. Three types of nanoparticles were studied: nano silver (nano-Ag), nano TiO2 (nano-TiO2), and carbon nanotubes (CNT). The quantification was based on a substance flow analysis from products to air, soil, and water in Switzerland. The following parameters were used as model inputs: estimated worldwide production volume, allocation of the production volume to product categories, particle release from products, and flow coefficients within the environmental compartments. The predicted environmental concentrations (PEC) were then compared to the predicted no effect concentrations (PNEC) derived from the literature to estimate a possible risk. The expected concentrations of the three nanoparticles in the different environmental compartments vary widely, caused by the different life cycles of the nanoparticle-containing products. The PEC values for nano-TiO2 in water are 0.7--16 microg/L and close to or higher than the PNEC value for nano-TiO2 (nano-Ag were much smaller than one, therefore comprising no reason to expect adverse effects from those particles. The results of this study make it possible for the first time to carry out a quantitative risk assessment of nanoparticles in the environment and suggest further detailed studies of nano-TiO2. PMID:18605569

  15. Self-Assembled Enzyme Nanoparticles for Carbon Dioxide Capture.

    Science.gov (United States)

    Shanbhag, Bhuvana Kamath; Liu, Boyin; Fu, Jing; Haritos, Victoria S; He, Lizhong

    2016-05-11

    Enzyme-based processes have shown promise as a sustainable alternative to amine-based processes for carbon dioxide capture. In this work, we have engineered carbonic anhydrase nanoparticles that retain 98% of hydratase activity in comparison to their free counterparts. Carbonic anhydrase was fused with a self-assembling peptide that facilitates the noncovalent assembly of the particle and together were recombinantly expressed from a single gene construct in Escherichia coli. The purified enzymes, when subjected to a reduced pH, form 50-200 nm nanoparticles. The CO2 capture capability of enzyme nanoparticles was demonstrated at ambient (22 ± 2 °C) and higher (50 °C) temperatures, under which the nanoparticles maintain their assembled state. The carrier-free enzymatic nanoparticles demonstrated here offer a new approach to stabilize and reuse enzymes in a simple and cost-effective manner. PMID:27109255

  16. Carbon black nanoparticles promote endothelial activation and lipid accumulation in macrophages independently of intracellular ROS production

    DEFF Research Database (Denmark)

    Cao, Yi; Roursgaard, Martin; Danielsen, Pernille Høgh; Møller, Peter; Loft, Steffen

    2014-01-01

    Exposure to nanoparticles (NPs) may cause vascular effects including endothelial dysfunction and foam cell formation, with oxidative stress and inflammation as supposed central mechanisms. We investigated oxidative stress, endothelial dysfunction and lipid accumulation caused by nano-sized carbon...... black (CB) exposure in cultured human umbilical vein endothelial cells (HUVECs), THP-1 (monocytes) and THP-1 derived macrophages (THP-1a). The proliferation of HUVECs or co-cultures of HUVECs and THP-1 cells were unaffected by CB exposure, whereas there was increased cytotoxicity, assessed by the LDH...

  17. Breath analysis to detect recent exposure to carbon monoxide

    OpenAIRE

    Cunnington, A; Hormbrey, P

    2002-01-01

    Objectives: To determine the normal range for carbon monoxide concentrations in the exhaled breath of subjects in the emergency department and to develop a protocol for the use of a breath analyser to detect abnormal carbon monoxide exposure.

  18. Multiwalled Carbon Nanotubes Decorated with Cobalt Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    D. G. Larrude

    2012-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs synthesized by spray pyrolysis were decorated with cobalt oxide nanoparticles using a simple synthesis route. This wet chemistry method yielded nanoparticles randomly anchored to the surface of the nanotubes by decomposition of cobalt nitrate hexahydrate diluted in acetone. Electron microscopy analysis indicated that dispersed particles were formed on the MWCNTs walls. The average size increased with the increasing concentration of cobalt nitrate in acetone in the precursor mixture. TEM images indicated that nanoparticles were strongly attached to the tube walls. The Raman spectroscopy results suggested that the MWCNT structure was slightly damaged after the nanoparticle growth.

  19. Morphological responses of Legionella pneumophila biofilm to nanoparticle exposure.

    Science.gov (United States)

    Stojak, Amber R; Raftery, Tara; Klaine, Stephen J; McNealy, Tamara L

    2011-12-01

    Legionella pneumophila is a pathogenic bacterium that forms biofilms in natural and anthropogenic habitats. This feature not only facilitates colonization but also limits the effectiveness of biocides. L. pneumophila was exposed to three sizes of citrate-capped gold nanospheres in both planktonic and biofilm stages. TEM micrographs indicated that gold nanoparticles (AuNPs) adsorbed to the bacterial cell surface, were absorbed into the cells, aggregated within the cells, and integrated into the extrapolymeric matrix of the biofilm. Both 4 and 18 nm, but not 50 nm AuNPs caused an alteration of biofilm morphology. Treatment with 20 nm polystyrene spheres did not induce these changes suggesting that the response was a result of the gold and not just the presence of the nanosphere. The morphological changes observed in the biofilm suggest that aquatic ecosystems may be affected by nanoparticle exposure. This may compromise ecosystem functions such as nutrient cycling facilitated by natural biofilms. PMID:21294606

  20. Carbon nanotubes/laser ablation gold nanoparticles composites

    International Nuclear Information System (INIS)

    The production of nanohybrids formed by oxidized multiwalled carbon nanotubes (MWCNTs) and nanoparticles, produced by pulsed laser ablation in liquids process, is described. The use of linkers, obtained by transformation of pyrene-1-butanol, is mandatory to generate an efficient and stable interaction between the two components. Transmission electron microscopy and X-ray photoelectron spectroscopy analysis showed the obtainment of the efficient coverage of the MWCNTs by nanoparticles composed by metal gold and, partially, by oxides. - Highlights: • Laser ablation is a used for the production of gold nanoparticle colloids • An efficient decoration of carbon nanotubes with nanoparticles is obtained through the use of a linker • This method allows an efficient and tunable preparation of carbon nanotube hybrids

  1. Interaction of carbon nanoparticles to serum albumin: elucidation of the extent of perturbation of serum albumin conformations and thermodynamical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Samir [Molecular and Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Hossain, Maidul [Biophysical Chemistry Laboratory, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Devi, P. Sujatha [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Kumar, Gopinatha Suresh [Biophysical Chemistry Laboratory, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Chaudhuri, Keya, E-mail: keya.chaudhuri@gmail.com [Molecular and Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India)

    2013-03-15

    Highlights: ► Strong interaction of serum albumins to CNPs and potential toxicity. ► Partial unfolding and alteration of BSA and HSA secondary structure by CNP. ► Significant insight into design of nanoparticles in biomedical applications. -- Abstract: Carbon nanoparticles continuously generated from industries and vehicles due to incomplete combustion of fuels is one of the potent causes of air pollution. The exposure of this polluted air with carbon nanoparticles, introduced into the bloodstream of animals in the course of respiration, motivated us to study their interaction with plasma proteins, bovine serum albumin and human serum albumin. Carbon nanoparticles with very small size and high purity were synthesized by dehydration of D-glucose using concentrated sulphuric acid as dehydrating agent. These were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy, FTIR spectroscopy and UV–visible spectroscopy. Carbon nanoparticles-protein interactions were studied by fluorescence spectroscopy, circular dichroism spectroscopy and isothermal titration calorimetry. The fluorescence quenching constants and thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were calculated, which indicated a strong static quenching and primary electrostatic interaction between the carbon nanoparticles and blood proteins. Circular dichroism spectra provided the information about the secondary structure alteration of the proteins in presence of carbon nanoparticles. These findings have shed light towards an understanding of the interactions between carbon nanoparticles and serum proteins which may clarify the potential risks and undesirable health effects of carbon nanoparticles, as well as the related cellular trafficking and systemic translocation.

  2. Interaction of carbon nanoparticles to serum albumin: elucidation of the extent of perturbation of serum albumin conformations and thermodynamical parameters

    International Nuclear Information System (INIS)

    Highlights: ► Strong interaction of serum albumins to CNPs and potential toxicity. ► Partial unfolding and alteration of BSA and HSA secondary structure by CNP. ► Significant insight into design of nanoparticles in biomedical applications. -- Abstract: Carbon nanoparticles continuously generated from industries and vehicles due to incomplete combustion of fuels is one of the potent causes of air pollution. The exposure of this polluted air with carbon nanoparticles, introduced into the bloodstream of animals in the course of respiration, motivated us to study their interaction with plasma proteins, bovine serum albumin and human serum albumin. Carbon nanoparticles with very small size and high purity were synthesized by dehydration of D-glucose using concentrated sulphuric acid as dehydrating agent. These were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy, FTIR spectroscopy and UV–visible spectroscopy. Carbon nanoparticles-protein interactions were studied by fluorescence spectroscopy, circular dichroism spectroscopy and isothermal titration calorimetry. The fluorescence quenching constants and thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were calculated, which indicated a strong static quenching and primary electrostatic interaction between the carbon nanoparticles and blood proteins. Circular dichroism spectra provided the information about the secondary structure alteration of the proteins in presence of carbon nanoparticles. These findings have shed light towards an understanding of the interactions between carbon nanoparticles and serum proteins which may clarify the potential risks and undesirable health effects of carbon nanoparticles, as well as the related cellular trafficking and systemic translocation

  3. Long Term Influence of Carbon Nanoparticles on Health and Liver Status in Rats.

    Directory of Open Access Journals (Sweden)

    Barbara Strojny

    Full Text Available Due to their excellent biocompatibility, carbon nanoparticles have been widely investigated for prospective biomedical applications. However, their impact on an organism with prolonged exposure is still not well understood. Here, we performed an experiment investigating diamond, graphene oxide and graphite nanoparticles, which were repeatedly administrated intraperitoneally into Wistar rats for four weeks. Some of the animals was sacrificed after the last injection, whereas the rest were sacrificed twelve weeks after the last exposure. We evaluated blood morphology and biochemistry, as well as the redox and inflammatory state of the liver. The results show the retention of nanoparticles within the peritoneal cavity in the form of prominent aggregates in proximity to the injection site, as well as the presence of some nanoparticles in the mesentery. Small aggregates were also visible in the liver serosa, suggesting possible transportation to the liver. However, none of the tested nanoparticles affected the health of animals. This lack of toxic effect may suggest the potential applicability of nanoparticles as drug carriers for local therapies, ensuring accumulation and slow release of drugs into a targeted tissue without harmful systemic side effects.

  4. Carbon black and titanium dioxide nanoparticles elicit distinct apoptotic pathways in bronchial epithelial cells

    OpenAIRE

    Baeza-Squiban Armelle; Fleury Jocelyne; Martens Johan A; Andreau Karine; Borot Marie-Caroline; Ferecatu Ioana; Thomassen Leen CJ; Hussain Salik; Marano Francelyne; Boland Sonja

    2010-01-01

    Abstract Background Increasing environmental and occupational exposures to nanoparticles (NPs) warrant deeper insight into the toxicological mechanisms induced by these materials. The present study was designed to characterize the cell death induced by carbon black (CB) and titanium dioxide (TiO2) NPs in bronchial epithelial cells (16HBE14o- cell line and primary cells) and to investigate the implicated molecular pathways. Results Detailed time course studies revealed that both CB (13 nm) and...

  5. Preventing carbon nanoparticle-induced lung inflammation reduces antigen-specific sensitization and subsequent allergic reactions in a mouse model

    OpenAIRE

    Kroker, Matthias; Sydlik, Ulrich; Autengruber, Andrea; Cavelius, Christian; Weighardt, Heike; Kraegeloh, Annette; Unfried, Klaus

    2015-01-01

    Background Exposure of the airways to carbonaceous nanoparticles can contribute to the development of immune diseases both via the aggravation of the allergic immune response in sensitized individuals and by adjuvant mechanisms during the sensitization against allergens. The cellular and molecular mechanisms involved in these adverse pathways are not completely understood. We recently described that the reduction of carbon nanoparticle-induced lung inflammation by the application of the compa...

  6. Carbon nanotube dosimetry: from workplace exposure assessment to inhalation toxicology

    OpenAIRE

    Erdely, Aaron; Dahm, Matthew; Chen, Bean T.; Zeidler-Erdely, Patti C.; Fernback, Joseph E.; Birch, M. Eileen; Evans, Douglas E.; Kashon, Michael L; Deddens, James A.; Hulderman, Tracy; Bilgesu, Suzan A; Battelli, Lori; Schwegler-Berry, Diane; Leonard, Howard D.; McKinney, Walter

    2013-01-01

    Background Dosimetry for toxicology studies involving carbon nanotubes (CNT) is challenging because of a lack of detailed occupational exposure assessments. Therefore, exposure assessment findings, measuring the mass concentration of elemental carbon from personal breathing zone (PBZ) samples, from 8 U.S.-based multi-walled CNT (MWCNT) manufacturers and users were extrapolated to results of an inhalation study in mice. Results Upon analysis, an inhalable elemental carbon mass concentration ar...

  7. Response of Fe powder, purified and as-produced HiPco single-walled carbon nanotubes to flash exposure

    International Nuclear Information System (INIS)

    The exposure of as-produced HiPCo single-walled carbon nanotubes (SWNTs) to a camera flash causes ignition, (oxidation) and subsequent coalescence of the Fe catalyst particles, while purified SWNTs do not respond to flashing. TEM and electron energy loss spectroscopy (EELS) analysis attribute the phenomena to the pyrophoric oxidation of Fe nanoparticles

  8. Resistive switching of alkanethiolated nanoparticle monolayers patterned by electron-beam exposure.

    Science.gov (United States)

    Reissner, Patrick A; Fedoryshyn, Yuriy; Tisserant, Jean-Nicolas; Stemmer, Andreas

    2016-08-17

    Carbon-based electronic devices are promising candidates for complementing silicon-based electronics in memory device applications. For example, sputtered thin films of amorphous carbon exhibit memristive behavior. The reported devices, however, have a minimal active area of about 50 nm diameter, leading to large set currents in the μA range. Although power efficiency would benefit from reduced drive currents, resistive switching of amorphous carbon confined to a few cubic nanometers has remained largely unexplored. Here, we investigate resistive switching in 30 nm long and 25 nm wide monolayer arrays of 10 nm gold nanoparticles patterned by direct electron-beam exposure followed by a purpose-designed emulsion-based development process. Electron-beam irradiation transforms the alkanethiol ligands of the gold nanoparticles into a solvent-resistant amorphous carbonaceous matrix allowing pattern development and imparting electronic function. We measure changes in conductivity of up to five orders of magnitude for set currents in the nA range. PMID:27492444

  9. Nanoparticle exposure in animals can be visualized in the skin and analysed via skin biopsy.

    Science.gov (United States)

    Sykes, Edward A; Dai, Qin; Tsoi, Kim M; Hwang, David M; Chan, Warren C W

    2014-01-01

    The increasing use of nanomaterials raises concerns about the long-term effects of chronic nanoparticle exposure on human health. However, nanoparticle exposure is difficult to evaluate non-invasively using current measurement techniques. Here we show that the skin is an important site of nanoparticle accumulation following systemic administration. Mice injected with high doses of gold nanoparticles have visibly blue skin while quantum dot-treated animals fluoresce under ultraviolet excitation. More importantly, elemental analysis of excised skin correlates with the injected dose and nanoparticle accumulation in the liver and spleen. We propose that skin analysis may be a simple strategy to quantify systemic nanoparticle exposure and predict nanoparticle fate in vivo. Our results suggest that in the future, dermal accumulation may also be exploited to trigger the release of ultraviolet and visible light-sensitive therapeutics that are currently impractical in vivo due to limits in optical penetration of tissues at these wavelengths. PMID:24823347

  10. A Review on the Respiratory System Toxicity of Carbon Nanoparticles

    OpenAIRE

    Maricica Pacurari; Kristine Lowe; Tchounwou, Paul B.; Ramzi Kafoury

    2016-01-01

    The respiratory system represents the main gateway for nanoparticles’ entry into the human body. Although there is a myriad of engineered nanoparticles, carbon nanoparticles/nanotubes (CNPs/CNTs) have received much attention mainly due to their light weight, very high surface area, durability, and their diverse applications. Since their discovery and manufacture over two decades ago, much has been learned about nanoparticles’ interactions with diverse biological system models. In particular, ...

  11. Photothermal Effects and Applications of Polydimethylsiloxane Membranes with Carbon Nanoparticles

    OpenAIRE

    Reinher Pimentel-Domínguez; Amado M. Velázquez-Benítez; J. Rodrigo Vélez-Cordero; Mathieu Hautefeuille; Francisco Sánchez-Arévalo; Juan Hernández-Cordero

    2016-01-01

    The advent of nanotechnology has triggered novel developments and applications for polymer-based membranes with embedded or coated nanoparticles. As an example, interaction of laser radiation with metallic and carbon nanoparticles has shown to provide optically triggered responses in otherwise transparent media. Incorporation of these materials inside polymers has led to generation of plasmonic and photothermal effects through the enhanced optical absorption of these polymer composites. In th...

  12. Size dependent phase diagrams of Nickel-Carbon nanoparticles

    CERN Document Server

    Magnin, Yann; Amara, Hakim; Ducastelle, François; Bichara, Christophe

    2015-01-01

    The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nanometers (807 Ni atoms). A tight binding model for interatomic interactions drives the Grand Canonical Monte Carlo simulations used to locate solid, core/shell and liquid stability domains, as a function of size, temperature and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should be taken into account in our understanding of the nanotube growth mechanisms.

  13. Synthesis of Carbon Encapsulated Mono- and Multi-Iron Nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Reza Sanaee

    2015-01-01

    Full Text Available Core–shell nanostructures of carbon encapsulated iron nanoparticles (CEINPs show unique properties and technological applications, because carbon shell provides extreme chemical stability and protects pure iron core against oxidation without impairing the possibility of functionalization of the carbon surface. Enhancing iron core magnetic properties and, in parallel, improving carbon shell sealing are the two major challenges in the synthesis of CEINPs. Here, we present the synthesis of both CEINPs and a new carbon encapsulated multi-iron nanoparticle by a new modified arc discharge reactor. The nanoparticle size, composition, and crystallinity and the magnetic properties have been studied. The morphological properties were observed by scanning electron microscopy and transmission electron microscopy. In order to evaluate carbon shell protection, the iron cores were characterized by selected area diffraction and fast Fourier transform techniques as well as by electron energy loss and energy dispersive X-ray spectroscopies. Afterward, the magnetic properties were investigated using a superconducting quantum interference device. As main results, spherical, oval, and multi-iron cores were controllably synthesized by this new modified arc discharge method. The carbon shell with high crystallinity exhibited sufficient protection against oxidation of pure iron cores. The presented results also provided new elements for understanding the growth mechanism of iron core and carbon shell.

  14. Carbon-Carbon Cross Coupling Reactions in Ionic Liquids Catalysed by Palladium Metal Nanoparticles

    OpenAIRE

    Martin H. G. Prechtl; Scholten, Jackson D.; Jairton Dupont

    2010-01-01

    A brief summary of selected pioneering and mechanistic contributions in the field of carbon-carbon cross-coupling reactions with palladium nanoparticles (Pd-NPs) in ionic liquids (ILs) is presented. Five exemplary model systems using the Pd-NPs/ILs approach are presented: Heck, Suzuki, Stille, Sonogashira and Ullmann reactions which all have in common the use of ionic liquids as reaction media and the use of palladium nanoparticles as reservoir for the catalytically active palladium species.

  15. Atomic Layer Deposition of Zirconium Oxide on Carbon Nanoparticles

    International Nuclear Information System (INIS)

    In this report we describe preparation of structures containing carbon nanoparticles for potential applications in nonvolatile memories. The carbon nanoparticles were synthesized from 5-methylresorcinol and formaldehyde via base catalysed polycondensation reaction, and were distributed over substrates by dip-coating the substrates into an organic solution. Before deposition of nanoparticles the substrates were covered with 2 nm thick Al2O3 layer grown by atomic layer deposition (ALD) from Al(CH3)3 and O3. After deposition of nanoparticles the samples were coated with ZrO2 films grown from C5H5Zr[N(CH3)2]3 and H2O. Both dielectrics were grown in two-temperature ALD processes starting deposition of Al2O3 at 25 °C and ZrO2 at 200 °C, thereafter completing both processes at a substrate temperature of 300 °C. Deposition of ZrO2 changed the structure of C-nanoparticles, which still remained in a Si/Al2O3/C/ZrO2 structure as a separate layer. Electrical characterization of nanostructures containing Al2O3 as tunnel oxide, C-nanoparticles as charge traps and ZrO2 as control oxide showed hysteretic flat-band voltage shift of about 1V

  16. Exposure Assessment and Inflammatory Response Among Workers Producing Calcium Carbonate Nanomaterials

    Science.gov (United States)

    Cui, Ling

    Problem: Nanotechnology is one of the most rapidly growing fields of science and engineering, and its applications have expanded to numerous research and industrial sectors, from consumer products to medicine to energy. Nano-materials and nanotechnology promise substantial benefits. However, there are many uncertainties and concerns regarding human health and the environment. Numerous toxicological studies on animals and cells in vitro have demonstrated that nanomaterials could cause various adverse health effects, including inflammation, oxidative stress, fibrosis and mutagenesis in the lungs, and cardiovascular and nervous system impairment. Objectives: The overall objective of this study was to characterize particulate exposures in a calcium carbonate nanoparticle manufacturing facility, investigate possible respiratory and cardiovascular effects, and explore the plausibility of an inflammatory mechanism. The associations between exposure level and various health outcomes were investigated. Methodology: Each job was characterized by mass, number and surface area concentration. Job classification was performed based on ranking of the exposure level and statistical models. Lung function tests, exhaled NO and blood pressure (BP) were measured before and after the workshift in the year of 2011. Inflammatory cytokines from induced sputum were measured cross-sectionally in the year of 2011. Data of lung function tests and blood pressure were collected cross-sectionally in the year of 2012. The associations between each exposure metric and health measures in 2012 were investigated. Only mass concentration was linked to both 2011 and 2012 health outcomes. Results: The sampling and analytic methodology used in the study presents the potential to characterize nanoparticle exposure for a variety of operational processes. We found the highest mass exposure occurred at bagging job whereas the highest number and surface area concentration was found at modification

  17. Nanoparticles of carbon allotropes inhibit glioblastoma multiforme angiogenesis in ovo

    Directory of Open Access Journals (Sweden)

    Grodzik M

    2011-11-01

    Full Text Available Marta Grodzik1, Ewa Sawosz1, Mateusz Wierzbicki1, Piotr Orlowski1, Anna Hotowy2, Tomasz Niemiec1, Maciej Szmidt3, Katarzyna Mitura4, André Chwalibog21Division of Biotechnology and Biochemistry of Nutrition, Warsaw University of Life Sciences, Warsaw, Poland; 2Department of Basic Animal and Veterinary Science, University of Copenhagen, Copenhagen, Denmark; 3Division of Histology and Embryology, Warsaw University of Life Sciences, Warsaw, Poland; 4Department of Biomedical Engineering, Koszalin University of Technology, Koszalin, PolandAbstract: The objective of the study was to determine the effect of carbon nanoparticles produced by different methods on the growth of brain tumor and the development of blood vessels. Glioblastoma multiforme cells were cultured on the chorioallantoic membrane of chicken embryo and after 7 days of incubation, were treated with carbon nanoparticles administered in ovo to the tumor. Both types of nanoparticles significantly decreased tumor mass and volume, and vessel area. Quantitative real-time polymerase chain reaction analysis showed downregulated fibroblast growth factor-2 and vascular endothelial growth factor expression at the messenger ribonucleic acid level. The present results demonstrate antiangiogenic activity of carbon nanoparticles, making them potential factors for anticancer therapy.Keywords: cancer, nanoparticle, embryo, angiogenesis, FGF-2, VEGF

  18. Concentration-dependent effects of carbon nanoparticles in gram-negative bacteria determined by infrared spectroscopy with multivariate analysis

    International Nuclear Information System (INIS)

    With increasing production of carbon nanoparticles (CNPs), environmental release of these entities becomes an ever-greater inevitability. However, many questions remain regarding their impact on soil microorganisms. This study examined the effects of long or short multiwalled carbon nanotubes (MWCNTs), C60 fullerene and fullerene soot in Gram-negative bacteria. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was applied to derive signature spectral fingerprints of effects. A concentration-dependent response in spectral alterations was observed for each nanoparticle type. Long or short MWCNTs and fullerene soot gave rise to similar alterations to lipids, Amide II and DNA. The extent of alteration varies with nanoparticle size, with smaller short MWCNTs resulting in greater toxicity than long MWCNTs. Fullerene soot was the least toxic. C60 results in the most distinct and largest overall alterations, notably in extensive protein alteration. This work demonstrates a novel approach for assaying and discriminating the effects of CNPs in target systems. - Highlights: ► Unique biochemical changes occur in bacteria following exposure to particular carbon nanoparticle. ► Biochemical alterations become more pronounced with increasing concentration. ► Smaller nanoparticles result in greater biochemical changes ascertained by IR spectroscopy with multivariate analysis. - Carbon nanoparticle-induced distinctive biochemical alterations in Gram-negative bacteria can be mechanistically fingerprinted using IR spectroscopy with multivariate analysis.

  19. Nanoparticles of carbon allotropes inhibit glioblastoma multiforme angiogenesis in ovo

    DEFF Research Database (Denmark)

    Grodzik, Marta; Sawosz, Ewa; Wierzbicki, Mateusz; Orlowski, Piotr; Hotowy, Anna Malgorzata; Niemiec, Tomasz; Szmidt, Maciej; Mitura, Katarzyna; Chwalibog, André

    2011-01-01

    The objective of the study was to determine the effect of carbon nanoparticles produced by different methods on the growth of brain tumor and the development of blood vessels. Glioblastoma multiforme cells were cultured on the chrioallantoic membrane of chicken embryo and after 7 days of incubati...

  20. Copper nanoparticle modified carbon electrode for determination of dopamine

    International Nuclear Information System (INIS)

    This paper reports the synthesis and characterization of copper nanoparticles (CuNPs) and application of copper nanoparticle-modified glassy carbon electrode for the electrochemical determination of dopamine. Electrochemical measurements were performed using differently modified glassy carbon (GC) electrodes. Bare, oxidized before modification and copper nanoparticle-modified glassy carbon electrodes (bare-GC, ox-GC and CuNP/GC electrodes, respectively) were characterized by cyclic voltammetry and electrochemical impedance spectroscopy in the presence of redox probes. Atomic force microscopy was used for the visualization of electrode surfaces. The CuNP/GC electrode was found to be suitable for the selective determination of dopamine even in the presence of ascorbic acid, uric acid, and p-acetamidophenol. The observed linear range of CuNP/GC for dopamine was from 0.1 nM to 1.0 μM while the detection limit was estimated to be 50 pM. It was demonstrated that here reported glassy carbon electrode modified by copper nanoparticles is suitable for the determination of dopamine in real samples such as human blood serum.

  1. Fluorescent Carbon Nanoparticles in Medicine for Cancer Therapy

    OpenAIRE

    Kumar, Vinit; Toffoli, Giuseppe; Rizzolio, Flavio

    2013-01-01

    Nanotechnology provides exciting opportunities for the development of novel, clinically relevant diagnostic and therapeutic multifunctional systems. Fluorescent carbon nanoparticles (CNPs) due to their intrinsic fluorescence and high biocompatibility are among the best candidates. As innovative nanomaterials, CNPs could be utilized both as nontoxic drug delivery system and bioimaging. We foresee a great future for CNPs in cancer diagnostic and therapy.

  2. Dispersion medium modulates oxidative stress response of human lung epithelial cells upon exposure to carbon nanomaterial samples

    International Nuclear Information System (INIS)

    Due to their large specific surface area, the potential of nanoparticles to be highly reactive and to induce oxidative stress is particularly high. In addition, some types of nanoparticles contain transition metals as trace impurities which are known to generate reactive oxygen species (ROS) in biological systems. This study investigates the potential of two types of single-walled carbon nanotube samples, nanoparticulate carbon black and crocidolite asbestos to induce ROS in lung epithelial cells in vitro. Carbon nanotube and carbon black samples were used as produced, without further purification or processing, in order to best mimic occupational exposure by inhalation of airborne dust particles derived from carbon nanomaterial production. Intracellular ROS were measured following short-term exposure of primary bronchial epithelial cells (NHBE) and A549 alveolar epithelial carcinoma cells using the redox sensitive probe carboxydichlorofluorescin (carboxy-DCFDA). The oxidative potential of agglomerated nanomaterial samples was compared following dispersion in cell culture medium with and without foetal calf serum (FCS) supplement. In addition, samples were dispersed in dipalmitoylphosphatidylcholine (DPPC), the major component of lung surfactant. It could be illustrated that in vitro exposure of lung epithelial cells to carbon nanomaterial samples results only in moderate or low oxidative stress under the exposure conditions employed. However, cell responses are strongly dependent on the vehicle used for dispersion. Whereas the presence of DPPC increased intracellular ROS formation, FCS seemed to protect the cells from oxidative insult.

  3. Oral subchronic exposure to silver nanoparticles in rats.

    Science.gov (United States)

    Garcia, Tania; Lafuente, Daisy; Blanco, Jordi; Sánchez, Domènec J; Sirvent, Juan J; Domingo, José L; Gómez, Mercedes

    2016-06-01

    Because of their extremely small size, silver nanoparticles (AgNPs) show unique physical and chemical properties, with specific biological effects, which make them particularly attractive for being used in a number of consumer applications. However, these properties also influence the potential toxicity of AgNPs. In this study, we assessed the potential toxic effects of an in vivo oral sub-chronic exposure to polyvinyl pyrrolidone coated AgNPs (PVP-AgNPs) in adult male rats. We also assessed if oral PVP-AgNPs exposure could alter the levels of various metals (Fe, Mg, Zn and Cu) in tissues. Rats were orally given 0, 50, 100 and 200 mg/kg/day of PVP-AgNPs. Silver (Ag) accumulation in tissues, Ag excretion, biochemical and hematological parameters, metal levels, as well as histopathological changes and subcellular distribution following PVP-AgNPs exposure, were also investigated. After 90 days of treatment, AgNPs were found within hepatic and ileum cells. The major tissue concentration of Ag was found in ileum of treated animals. However, all tissues of PVP-AgNPs-exposed animals showed increased levels of Ag in comparison with those of rats in the control group. No harmful effects in liver and kidney, as well as in biochemical markers were noted at any treatment dose. In addition, no hematological or histopathological changes were found in treated animals. However, significant differences in Cu and Zn levels were found in thymus and brain of PVP-AgNPs-treated rats. PMID:27090107

  4. Cardiovascular deaths related to Carbon monoxide Exposure in Ahvaz, Iran

    OpenAIRE

    Gholamreza Goudarzi; Sahar Geravandi; Mehdi Vosoughi; Mohammad javad Mohammadi; Abdolkazem neisi; Sepideh sadat Taghavirad

    2014-01-01

    Carbon monoxide is an odorless, colorless and toxic gas that emitted from combustion. Carbon monoxide can cause harmful health effects by reducing oxygen delivery to the body's organs (like the heart and brain), tissues, fibrinolysis effects, abortion and death at extremely high levels. The aim of this study was to assess health- effects of carbon monoxide exposure in Ahvaz city. Data were collected through Ahvaz Meteorological Organization and Department of Environment. Raw data processing b...

  5. Occupational Exposure to Carbon Nanotubes and Nanofibers

    Science.gov (United States)

    ... increased risk of exposure to new nanomaterials. Today, nanomaterials are found in hundreds of products, ranging from cosmetics, to clothing, to industrial and biomedical applications. These nanoscale-based products are typically called "first ...

  6. Toxicity of copper nanoparticles to Daphnia magna under different exposure conditions.

    Science.gov (United States)

    Xiao, Yinlong; Peijnenburg, Willie J G M; Chen, Guangchao; Vijver, Martina G

    2016-09-01

    Although the risks of metallic nanoparticles (NPs) to aquatic organisms have already been studied for >10years, our understanding of the link between the fate of particles in exposure medium and their toxicity is still in its infancy. Moreover, most of the earlier studies did not distinguish the contribution of particles and soluble ions to the toxic effects caused by suspensions of metallic NPs. In this study, the toxicity of CuNPs to Daphnia magna upon modification of the exposure conditions, achieved by aging the suspensions of CuNPs and by altering water chemistry parameters like the pH and levels of dissolved organic carbon (DOC), was investigated. The LC50 values for CuNPs exposure decreased by about 30% after 7days of aging. The LC50 values increased >12-fold upon addition of DOC at concentrations ranging from 0 to 10mg/L to the exposure medium. Changing the pH from 6.5 to 8.5 resulted in a 3-fold higher LC50 value. Furthermore, it was found that during 7days of aging of the exposure medium (without addition of DOC and at pH7.8), the toxicity could be mostly ascribed to the particles present in the suspension (around 70%). However, adding DOC or decreasing the pH of the exposure medium reduced the contribution of the particles to the observed toxicity. We thus found that the effective concentration regarding the toxicity was mainly driven by the contribution of the soluble ions in the presence of DOC or at pH6.5. Our results suggest that the toxicity results of CuNPs obtained from laboratory tests may overestimate the risk of the particles in polluted waters due to the common absence of DOC in laboratory test solutions. Moreover, the role of the ions shedding from CuNPs is very important in explaining the toxicity in natural waters. PMID:27135569

  7. Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging

    OpenAIRE

    Goldie Oza; Ravichandran, M.; Victor-Ishrayelu Merupo; Sachin Shinde; Ashmi Mewada; Jose Tapia Ramirez; Velumani, S.; Madhuri Sharon; Maheshwar Sharon

    2016-01-01

    A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydrid...

  8. Porous Carbon-Supported Gold Nanoparticles for Oxygen Reduction Reaction: Effects of Nanoparticle Size.

    Science.gov (United States)

    Wang, Likai; Tang, Zhenghua; Yan, Wei; Yang, Hongyu; Wang, Qiannan; Chen, Shaowei

    2016-08-17

    Porous carbon-supported gold nanoparticles of varied sizes were prepared using thiolate-capped molecular Au25, Au38, and Au144 nanoclusters as precursors. The organic capping ligands were removed by pyrolysis at controlled temperatures, resulting in good dispersion of gold nanoparticles within the porous carbons, although the nanoparticle sizes were somewhat larger than those of the respective nanocluster precursors. The resulting nanocomposites displayed apparent activity in the electroreduction of oxygen in alkaline solutions, which increased with decreasing nanoparticle dimensions. Among the series of samples tested, the nanocomposite prepared with Au25 nanoclusters displayed the best activity, as manifested by the positive onset potential at +0.95 V vs RHE, remarkable sustainable stability, and high numbers of electron transfer at (3.60-3.92) at potentials from +0.50 to +0.80 V. The performance is comparable to that of commercial 20 wt % Pt/C. The results demonstrated the unique feasibility of porous carbon-supported gold nanoparticles as high-efficiency ORR catalysts. PMID:27454707

  9. Modified carbon nanoparticle-chitosan film electrodes: Physisorption versus chemisorption

    Energy Technology Data Exchange (ETDEWEB)

    Rassaei, Liza; Sillanpaeae, Mika [Laboratory of Applied Environmental Chemistry, Department of Environmental Sciences, University of Kuopio, Patteristonkatu 1, 50101 Mikkeli (Finland); Marken, Frank [Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom)

    2008-08-01

    Surface functionalised carbon nanoparticles of ca. 8 nm diameter co-assemble with chitosan into stable thin film electrodes at glassy carbon surfaces. Robust electrodes for application in sensing or electrocatalysis are obtained in a simple solvent evaporation process. The ratio of chitosan binder backbone to carbon nanoparticle conductor determines the properties of the resulting films. Chitosan (a poly-D-glucosamine) has a dual effect (i) as the binder for the mesoporous carbon composite structure and (ii) as binding site for redox active probes. Physisorption due to the positively charged ammonium group (pK{sub A} {approx} 6.5) occurs, for example, with anionic indigo carmine (a reversible 2e{sup -}-2H{sup +} reduction system in aqueous media). Chemisorption at the amine functionalities is demonstrated with 2-bromo-methyl-anthraquinone in acetonitrile (resulting in a reversible 2e{sup -}-2H{sup +} anthraquinone reduction system in aqueous media). Redox processes within the carbon nanoparticle-chitosan films are studied and at sufficiently high scan rates diffusion of protons (buffer concentration depended) is shown to be rate limiting. The chemisorption process provides a much more stable interfacial redox system with a characteristic and stable pH response over a pH 2-12 range. Chemisorption and physisorption can be employed simultaneously in a complementary binding process. (author)

  10. Photothermal Effects and Applications of Polydimethylsiloxane Membranes with Carbon Nanoparticles

    Directory of Open Access Journals (Sweden)

    Reinher Pimentel-Domínguez

    2016-03-01

    Full Text Available The advent of nanotechnology has triggered novel developments and applications for polymer-based membranes with embedded or coated nanoparticles. As an example, interaction of laser radiation with metallic and carbon nanoparticles has shown to provide optically triggered responses in otherwise transparent media. Incorporation of these materials inside polymers has led to generation of plasmonic and photothermal effects through the enhanced optical absorption of these polymer composites. In this work, we focus on the photothermal effects produced in polydimethylsiloxane (PDMS membranes with embedded carbon nanoparticles via light absorption. Relevant physical parameters of these composites, such as nanoparticle concentration, density, geometry and dimensions, are used to analyze the photothermal features of the membranes. In particular, we analyze the heat generation and conduction in the membranes, showing that different effects can be achieved and controlled depending on the physical and thermal properties of the composite material. Several novel applications of these light responsive membranes are also demonstrated, including low-power laser-assisted micro-patterning and optomechanical deformation. Furthermore, we show that these polymer-nanoparticle composites can also be used as coatings in photonic and microfluidic applications, thereby offering an attractive platform for developing light-activated photonic and optofluidic devices.

  11. Lung toxicities of core–shell nanoparticles composed of carbon, cobalt, and silica

    Directory of Open Access Journals (Sweden)

    Al Samri MT

    2013-03-01

    Full Text Available Mohammed T Al Samri,1,* Rafael Silva,2,* Saeeda Almarzooqi,3 Alia Albawardi,3 Aws Rashad Diab Othman,1 Ruqayya SMS Al Hanjeri,1 Shaikha KM Al Dawaar,1 Saeed Tariq,4 Abdul-Kader Souid,1 Tewodros Asefa2,51Department of Pediatrics, United Arab Emirates University, Abu Dhabi, United Arab Emirates; 2Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, USA; 3Department of Pathology, 4Department of Anatomy, United Arab Emirates University, Abu Dhabi, United Arab Emirates; 5Department of Chemical Engineering and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ, USA*These authors contributed equally to this workAbstract: We present here comparative assessments of murine lung toxicity (biocompatibility after in vitro and in vivo exposures to carbon (C–SiO2-etched, carbon–silica (C–SiO2, carbon–cobalt–silica (C–Co–SiO2, and carbon–cobalt oxide–silica (C–Co3O4–SiO2 nanoparticles. These nanoparticles have potential applications in clinical medicine and bioimaging, and thus their possible adverse events require thorough investigation. The primary aim of this work was to explore whether the nanoparticles are biocompatible with pneumatocyte bioenergetics (cellular respiration and adenosine triphosphate content. Other objectives included assessments of caspase activity, lung structure, and cellular organelles. Pneumatocyte bioenergetics of murine lung remained preserved after treatment with C–SiO2-etched or C–SiO2 nanoparticles. C–SiO2-etched nanoparticles, however, increased caspase activity and altered lung structure more than C–SiO2 did. Consistent with the known mitochondrial toxicity of cobalt, both C–Co–SiO2 and C–Co3O4–SiO2 impaired lung tissue bioenergetics. C–Co–SiO2, however, increased caspase activity and altered lung structure more than C–Co3O4–SiO2. The results indicate that silica shell is essential for

  12. Design of an exposure chamber to test samplers used in the evaluation of personal exposure to nanoparticles

    Science.gov (United States)

    Amin, R.; Izadi, H.; Quémerais, B.

    2015-05-01

    The aim of this study was to design a laboratory size exposure chamber for the testing of samplers used to collect personal exposure samples for nanoparticles. A polyethylene cylindrical container with a diameter of 42 cm and height of 60 cm was used as the testing chamber. The chamber was divided into 2 parts by an aluminium honey comb. Particles generated using a 1 jet Collison nebulizer (BGI) operating at a flow rate of 4L/min were inserted into the chamber via a tube located near to the top of the chamber. A heater was inserted just after the nebulizer to avoid condensation of water in the tubing, and dilution air, running at 10L/min was inserted just after the heater. As particle charge can dramatically affect sampling a particle neutralizer was attached to the generation system so as to neutralize the particles before they enter the chamber. A diffusion dryer was used to remove any water from the air stream prior to enter the chamber. A fan was used to mix and distribute the generated particles. After generation and mixing, the particles passed through the aluminium honeycomb which is essential to eliminate any turbulent or unwanted air flow. Six sampling ports along with a pressure gauge were placed on the walls 15 cm from the bottom of the chamber. The pressure gauge was added to ensure the desired pressure is achieved during sampling. The sampling ports allowed for the connection of five samplers and sampling pumps as well as the connection of an ultrafine particle counter. The exposure chamber was developed to assess various samplers for carbon nanotubes and cellulose nanocrystals. Results showed that the chamber was working properly and that mixing was sufficiently uniform to test samplers.

  13. Apparatus for producing carbon-coated nanoparticles and carbon nanospheres

    Science.gov (United States)

    Perry, W. Lee; Weigle, John C.; Phillips, Jonathan

    2015-10-20

    An apparatus for producing carbon-coated nano- or micron-scale particles comprising a container for entraining particles in an aerosol gas, providing an inlet for carbon-containing gas, providing an inlet for plasma gas, a proximate torch for mixing the aerosol gas, the carbon-containing gas, and the plasma gas, bombarding the mixed gases with microwaves, and providing a collection device for gathering the resulting carbon-coated nano- or micron-scale particles. Also disclosed is a method and apparatus for making hollow carbon nano- or micro-scale spheres.

  14. Assessment of exposure to composite nanomaterials and development of a personal respiratory deposition sampler for nanoparticles

    Science.gov (United States)

    Cena, Lorenzo

    2011-12-01

    The overall goals of this doctoral dissertation are to provide knowledge of workers' exposure to nanomaterials and to assist in the development of standard methods to measure personal exposure to nanomaterials in workplace environments. To achieve the first goal, a field study investigated airborne particles generated from the weighing of bulk carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. This study also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood and biosafety cabinet) for control of exposure to particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured with direct-read instruments, and particle morphology was determined by electron microscopy. Sanding of CNT-epoxy nanocomposites released respirable size airborne particles with protruding CNTs very different in morphology from bulk CNTs that tended to remain in clusters (>1mum). Respirable mass concentrations in the operator's breathing zone were significantly greater when sanding took place in the custom hood (p workplace levels was found to have no significant effect (2-way ANOVA, p=0.257) on the performance of the impactor. The effective deposition of particles onto the diffusion stage was found to match the NPM criterion, showing that a sample collected with the NRD sampler represents the concentration of nanoparticles deposited in the human respiratory system.

  15. Ostwald Ripening of Platinum Nanoparticles Confined in a Carbon Nanotube/Silica-Templated Cylindrical Space

    Directory of Open Access Journals (Sweden)

    Cintia Mateo-Mateo

    2012-01-01

    Full Text Available Sintering of nanoparticles mediated by an Ostwald ripening mechanism is generally assessed examining the final particle size distributions. Based on this methodology, a general approach for depositing platinum nanoparticles onto carbon nanotubes in solution has been employed in order to evaluate the sintering process of these metallic nanoparticles at increasing temperatures in a carbon nanotube/silica-templated confined space.

  16. Ostwald Ripening of Platinum Nanoparticles Confined in a Carbon Nanotube/Silica-Templated Cylindrical Space

    OpenAIRE

    Cintia Mateo-Mateo; Carmen Vázquez-Vázquez; Moisés Pérez-Lorenzo; Verónica Salgueiriño; Correa-Duarte, Miguel A.

    2012-01-01

    Sintering of nanoparticles mediated by an Ostwald ripening mechanism is generally assessed examining the final particle size distributions. Based on this methodology, a general approach for depositing platinum nanoparticles onto carbon nanotubes in solution has been employed in order to evaluate the sintering process of these metallic nanoparticles at increasing temperatures in a carbon nanotube/silica-templated confined space.

  17. Occupational exposure to carbon black: a particulate sampling study.

    Science.gov (United States)

    Smith, R G; Musch, D C

    1982-12-01

    In order to determine the particulate exposure levels within carbon black production plants, a sampling survey involving workers from seven carbon black producers was initiated in late 1979. A total of 1,951 acceptable samples (1,564 total dust and 387 respirable dust) were collected from closed-face filter cassettes worn by carbon black workers performing normal work operations. A one-centimeter cyclone separator was employed for respirable dust sampling. Overall sampling distributions of the time-weighted average values generated from the survey were best described by the log-normal distribution. Characterization of the particulate exposures to workers is provided for the various areas of employment and specific jobs within these areas. Summary geometric mean time-weighted average values by area of employment and by job category are well within the carbon black permissible exposure limit (PEL) of 3.5 mg/m3. Identification of those job categories subject to relatively higher particulate exposures, and quantification of these exposures, is essential to the effective industrial hygiene monitoring and control of worker exposures. PMID:7158607

  18. Evaluation of the tracing effect of carbon nanoparticle and carbon nanoparticle-epirubicin suspension in axillary lymph node dissection for breast cancer treatment

    OpenAIRE

    Du, Junze; Zhang, Yongsong; Ming, Jia; Liu, Jing; Zhong, Ling; Liang, Quankun; Fan, Linjun; Jiang, Jun

    2016-01-01

    Abstracts Background Carbon nanoparticle suspension, using smooth carbon particles at a diameter of 21 nm added with suspending agents, is a stable suspension of carbon pellets of 150 nm in diameter. It is obviously inclined to the lymphatic system. There were some studies reporting that carbon nanoparticles are considered as superior tracers for sentinel lymph nodes because of their stability and operational feasibility. However, there were few study concerns about the potential treatment ef...

  19. Nanoparticle exposure in animals can be visualized in the skin and analyzed via skin biopsy

    OpenAIRE

    Sykes, Edward A; Dai, Qin; Tsoi, Kim M.; Hwang, David M.; Chan, Warren C. W.

    2014-01-01

    The increased manufacture and use of nanomaterials raises concerns about the long-term effects of chronic exposure on human health. However, nanoparticle exposure remains difficult to measure. Here we show that mice intravenously administered with high doses of gold nanoparticles have visibly blue skin while quantum dot-treated mice emit green, yellow, or red fluorescence after ultraviolet excitation. More importantly, elemental analysis of excised skin correlates with the injected dose and n...

  20. Nickel Nanoparticles for Enhancing Carbon Capture

    OpenAIRE

    Gaurav Ashok Bhaduri; Mohammed A. H. Alamiry; Lidija Šiller

    2015-01-01

    Hydration reaction of CO2 is one of the rate limiting steps for CO2 absorption (in aqueous solutions) and aqueous CO2 mineralization. The catalytic activity of nickel nanoparticles (NiNPs) for CO2 hydration is studied at different temperatures, pH, and low CO2 partial pressures to mimic the true flue gas conditions. Results show that NiNPs can work as active catalyst for hydration of CO2 in applications such as CO2 separation and CO2 mineralization. The NiNPs display optimum activity within 2...

  1. A facile hydrothermal approach for construction of carbon coating on TiO2 nanoparticles

    Science.gov (United States)

    Olurode, Kehinde; Neelgund, Gururaj M.; Oki, Aderemi; Luo, Zhiping

    2012-04-01

    Herein a facile hydrothermal approach is used to construct carbon coated TiO2 nanoparticles employing dextrose as the source of carbon. The procedure is operated at a low temperature of 200 °C. Fourier infrared spectroscopy demonstrated the successful coating of carbon on TiO2 nanoparticles. The phase composition of TiO2 and carbon coated TiO2 nanoparticles were studied using X-ray diffraction and the surface morphology was analyzed by scanning and transmission electron microscopy. The existence of carbon coating on TiO2 nanoparticles was revealed by thermogravimetric analysis through different thermograms exhibited for TiO2 and carbon coated TiO2 nanoparticles. The reported method offers a simple and efficient approach for production of carbon coated TiO2 nanoparticles.

  2. Preparation of Dispersed Platinum Nanoparticles on a Carbon Nanostructured Surface Using Supercritical Fluid Chemical Deposition

    Directory of Open Access Journals (Sweden)

    Mineo Hiramatsu

    2010-03-01

    Full Text Available We have developed a method of forming platinum (Pt nanoparticles using a metal organic chemical fluid deposition (MOCFD process employing a supercritical fluid (SCF, and have demonstrated the synthesis of dispersed Pt nanoparticles on the surfaces of carbon nanowalls (CNWs, two-dimensional carbon nanostructures, and carbon nanotubes (CNTs. By using SCF-MOCFD with supercritical carbon dioxide as a solvent of metal-organic compounds, highly dispersed Pt nanoparticles of 2 nm diameter were deposited on the entire surface of CNWs and CNTs. The SCF-MOCFD process proved to be effective for the synthesis of Pt nanoparticles on the entire surface of intricate carbon nanostructures with narrow interspaces.

  3. Plasma exposure tests of a carbon fiber/epoxy composite

    International Nuclear Information System (INIS)

    An experiment was conducted to test the exposure of a vacuum chamber made of a carbon fiber/epoxy composite to a plasma environment. In previous tests this material(CE 339, made by Ferro Corp.) has shown good vacuum properties and has also demonstrated the capability to withstand high energy electron beams in tests at the Naval Research Laboratory. Based on these promising results, the Torsatron Group at Auburn University conducted plasma exposure tests on a section of carbon fiber/epoxy composite pipe furnished by Oak Ridge National Laboratory. 1 ref, 2 figs

  4. Controlling silver nanoparticle exposure in algal toxicity testing - A matter of timing

    DEFF Research Database (Denmark)

    Sørensen, Sara Nørgaard; Baun, Anders

    2015-01-01

    The aquatic ecotoxicity testing of nanoparticles is complicated by unstable exposure conditions resulting from various transformation processes of nanoparticles in aqueous suspensions. In this study, we investigated the influence of exposure timing on the algal test response to silver nanoparticles...... test was found applicable for dissolved silver, but yielded non-monotonous concentration–response relationships and poor reproducibility for freshly prepared AgNP suspensions. However, when aging AgNPs in algal medium 24 h prior to testing, clear concentration–response patterns emerged and...

  5. Carbonation acceleration of calcium hydroxide nanoparticles: induced by yeast fermentation

    Science.gov (United States)

    Lopez-Arce, Paula; Zornoza-Indart, Ainara

    2015-09-01

    Carbonation of Ca(OH)2 nanoparticles and consolidation of limestone are accelerated by high humidity and a yeast fermentation system that supplies a saturated atmosphere on CO2, H2O vapor and ethanol during 28 days. Nanoparticles were analyzed by X-ray diffraction and differential thermal analyses with thermogravimetry. Spectrophotometry, scanning electron microscopy analyses, and hydric and mechanical tests were also performed in stones specimens. Samples exposed to the yeast environment achieve 100 % relative CaCO3 yield, whereas at high humidity but without the yeast and under laboratory environment, relative yields of 95 % CaCO3 and 15 % CaCO3 are, respectively, reached, with white crusts and glazing left on the stone surfaces when the nanoparticles are applied at a concentration of 25 g/l. The largest increase in the drilling resistance and surface hardness values with slight increase in the capillarity absorption and desorption coefficients and with lesser stone color changes are produced at a concentration of 5 g/l, in the yeast system environment. This especially happens in stone specimens initially with bimodal pore size distributions, more amounts of pores with diameters between 0.1 and 1 µm, higher open porosity values and faster capillary coefficients. An inexpensive and reliable method based on water and yeast-sugar solution is presented to speed up carbonation of Ca(OH)2 nanoparticles used as a consolidating product to improve the mechanical properties of decayed limestone from archaeological and architectural heritage.

  6. Personal exposure to Black Carbon in transport microenvironments

    Science.gov (United States)

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Wets, Geert

    2012-08-01

    We evaluated personal exposure of 62 individuals to the air pollutant Black Carbon, using 13 portable aethalometers while keeping detailed records of their time-activity pattern and whereabouts. Concentrations encountered in transport are studied in depth and related to trip motives. The evaluation comprises more than 1500 trips with different transport modes. Measurements were spread over two seasons. Results show that 6% of the time is spent in transport, but it accounts for 21% of personal exposure to Black Carbon and approximately 30% of inhaled dose. Concentrations in transport were 2-5 times higher compared to concentrations encountered at home. Exposure was highest for car drivers, and car and bus passengers. Concentrations of Black Carbon were only half as much when traveling by bike or on foot; when incorporating breathing rates, dose was found to be twice as high for active modes. Lowest 'in transport' concentrations were measured in trains, but nevertheless these concentrations are double the concentrations measured at home. Two thirds of the trips are car trips, and those trips showed a large spread in concentrations. In-car concentrations are higher during peak hours compared to off-peak, and are elevated on weekdays compared to Saturdays and even more so on Sundays. These findings result in significantly higher exposure during car commute trips (motive 'Work'), and lower concentrations for trips with motive 'Social and leisure'. Because of the many factors influencing exposure in transport, travel time is not a good predictor of integrated personal exposure or inhaled dose.

  7. Carbon Nanoparticles in Nematic Liquid Crystals

    Institute of Scientific and Technical Information of China (English)

    S.Eren San; Mustafa Okutan; O(g)uz K(o)ysal; Yusuf Yer-li

    2008-01-01

    Fullerene G60,C70,single-walled and multi-walled carbon nanotubes and graphene sheets are doped to nematic liquid crystal(LC)host in the same percentage.Planar samples of these mixtures are prepared and our measurements constitute an optimization basis for possible applications.Fullerene balls are found to be the best compatible material for optical aims and reorientation of LC molecules,while the carbon nanotubes experience some reorientation possibility in LC media and graphene layers are good barriers to preserve reorientation.

  8. Presence of Amorphous Carbon Nanoparticles in Food Caramels

    OpenAIRE

    Md Palashuddin Sk; Amit Jaiswal; Anumita Paul; Siddhartha Sankar Ghosh; Arun Chattopadhyay

    2012-01-01

    We report the finding of the presence of carbon nanoparticles (CNPs) in different carbohydrate based food caramels, viz. bread, jaggery, sugar caramel, corn flakes and biscuits, where the preparation involves heating of the starting material. The CNPs were amorphous in nature; the particles were spherical having sizes in the range of 4–30 nm, depending upon the source of extraction. The results also indicated that particles formed at higher temperature were smaller than those formed at lower ...

  9. Electrochemical Properties of Carbon Nanoparticles Entrapped in Silica Matrix

    OpenAIRE

    Bok, Sangho; Lubguban, Arnold A.; Gao, Yuanfang; Bhattacharya, Shantanu; Korampally, Venu; Hossain, Maruf; Gillis, Kevin D.; Gangopadhyay, Shubhra

    2008-01-01

    Carbon-based electrode materials have been widely used for many years for electrochemical charge storage, energy generation, and catalysis. We have developed an electrode material with high specific capacitance by entrapping graphite nanoparticles into a sol-gel network. Films from the resulting colloidal suspensions were highly porous due to the removal of the entrapped organic solvents from sol-gel matrix giving rise to high Brunauer-Emmett-Teller (BET) specific surface areas (654 m2/g) and...

  10. Redeposition of electrochemically dissolved platinum as nanoparticles on carbon

    DEFF Research Database (Denmark)

    Norgaard, C. F.; Stamatin, S. N.; Skou, E. M.

    2014-01-01

    Electrochemical dissolution of platinum has been proposed by several research groups as an environmentally friendly way to recover platinum from catalytic structures such as fuel cell electrodes. For the case of electrochemical dissolution of platinum in hydrochloric acid electrolyte, the present...... communication reports a simple chemical method for reprecipitating platinum as nanoparticles of reasonable particle size on a carbon substrate without intermediary separation and handling of solid platinum salt. After electrochemical dissolution, platinum was reprecipitated using a polyol based method. Platinum...

  11. Laser-generated plasma by carbon nanoparticles embedded into polyethylene

    Czech Academy of Sciences Publication Activity Database

    Torrisi, L.; Ceccio, G.; Cutroneo, Mariapompea

    2016-01-01

    Roč. 375, MAY (2016), s. 93-99. ISSN 0168-583X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : carbon nanoparticles * laser -generated plasma * Time-of-flight measurements * advanced targets Subject RIV: BG - Nuclear, Atomic and Molecular Physics , Colliders Impact factor: 1.124, year: 2014

  12. Evaluation of exposure to carbon monoxide associated with passive smoking

    International Nuclear Information System (INIS)

    The current study measured breath carbon monoxide (CO) concentrations prior to and at prescribed time intervals after exposure to passive smoking under controlled conditions, along with the air CO concentration in the exposure room during the exposure periods. The postexposure breath CO levels were 1.4-2.7 times higher than the background breath CO levels after 30 min of exposure, yet only slightly higher after 10 min of exposure, thereby confirming that exposure to CO from passive smoking causes a significant body burden of CO. The air CO concentration gradually increased during the burning of a cigarette(s), regardless of the exposure duration, whereas it slightly decreased after burning. However, the pattern of breath CO decay was similar for the two different types of exposure (during and after a cigarette(s)) in each subject. The decrease in the postexposure alveolar CO concentrations was slow even in the early phase of the decay curves, indicating a monocompartment uptake and elimination model for the human body. The half-lives (78-277 min) estimated in the present study were comparable to those reported in previous studies associated with CO exposure from active smoking or other activities. The current study also evaluated the CO exposure of visitors and workers at three different types of recreation facility (bars, Internet cafes, and billiard halls) typically associated with passive smoking. The results confirmed that passive smoking is the major contributor to the CO exposure of nonsmoking visitors in a recreation environment. In addition, workplace exposure to CO from passive smoking was found to be the most important contributor to the daily CO exposure of nonsmoking recreation workers

  13. Occupational exposure to carbon black in its manufacture.

    Science.gov (United States)

    Gardiner, K; Trethowan, W N; Harrington, J M; Calvert, I A; Glass, D C

    1992-10-01

    Carbon black is manufactured by the vapour phase pyrolysis of heavy aromatic hydrocarbon feedstocks. Its manufacture is worldwide and the majority of its production is for use in the rubber industry especially tyre manufacture. Its carbonaceous nature has led many to investigate the occurrence of exposure-related medical conditions. To quantify any such relationships, it is necessary to assess exposure accurately. As part of such an epidemiological investigation survey involving the measurement both of respirable and of total inhalable carbon black was undertaken in 18 plants in seven European countries between mid-1987 and mid-1989. A total of 1298 respirable samples (SIMPEDS cyclone) and 1317 total inhalable samples (IOM head) were taken and deemed of sufficient quality for inclusion in the study. The distributions of the time-weighted average values were assessed and found to be best described by a log-normal distribution, and so exposure is characterized by geometric means and standard deviations. The data are presented in terms of 13 separate job titles for both dust fractions and shows a wide variation between job titles, with the highest mean exposure experienced by the site cleaners, and 30% of the samples taken from the warehouse packers being in excess of the relevant countries' occupational exposure limits for total inhalable dust. The quality and extent of this data allows both for comparison with exposure standards and for generation of occupational exposure indices, which will be presented in another paper (Gardiner et al., in preparation). PMID:1444068

  14. How important is drinking water exposure for the risks of engineered nanoparticles to consumers?

    DEFF Research Database (Denmark)

    Tiede, Karen; Hansen, Steffen Foss; Westerhoff, Paul;

    2016-01-01

    This study explored the potential for engineered nanoparticles (ENPs) to contaminate the UK drinking water supplies and established the significance of the drinking water exposure route compared to other routes of human exposure. A review of the occurrence and quantities of ENPs in different...

  15. Cardiovascular deaths related to Carbon monoxide Exposure in Ahvaz, Iran

    Directory of Open Access Journals (Sweden)

    Gholamreza Goudarzi

    2014-08-01

    Full Text Available Carbon monoxide is an odorless, colorless and toxic gas that emitted from combustion. Carbon monoxide can cause harmful health effects by reducing oxygen delivery to the body's organs (like the heart and brain, tissues, fibrinolysis effects, abortion and death at extremely high levels. The aim of this study was to assess health- effects of carbon monoxide exposure in Ahvaz city. Data were collected through Ahvaz Meteorological Organization and Department of Environment. Raw data processing by Excel software includes (instruction set correction of averaging, coding and filtering and after the impact of meteorological parameters was converted as input file to the Air Q model. Finally, health-effects of carbon monoxide exposure were calculated. The results showed that the concentration of carbon monoxide was 7.41 mg/m3 in Ahvaz as annual average. Sum of total numbers of deaths attributed to carbon monoxide was 16 cases within a year. Approximately 4.3% of total Cardiovascular deaths happened when the carbon monoxide concentrations was more than 20 mg/m3. This could be due to higher fuel consumption gasoline in vehicles, Oil industry, steel and Heavy industries in Ahwaz. Mortality and Morbidity risks were detected at current ambient concentrations of air pollutants.

  16. Identification of promoters and enhancers induced by carbon nanotube exposure

    DEFF Research Database (Denmark)

    Bornholdt, Jette; Lilje, Berit; Saber, Anne Thoustrup;

    Usage of carbon nanotubes (CNTs) is increasing in industry due to their mechanical and electrical properties. However, pulmonary exposure to CNTs induces, an asbestos-like toxicological response characterized by persistent inflammation, granuloma formation and fibrosis with low no-effect levels...

  17. Search of medical literature for indoor carbon monoxide exposure

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, T.; Ivanovich, M.

    1995-12-01

    This report documents a literature search on carbon monoxide. The search was limited to the medical and toxicological databases at the National Library of Medicine (MEDLARS). The databases searched were Medline, Toxline and TOXNET. Searches were performed using a variety of strategies. Combinations of the following keywords were used: carbon, monoxide, accidental, residential, occult, diagnosis, misdiagnosis, heating, furnace, and indoor. The literature was searched from 1966 to the present. Over 1000 references were identified and summarized using the following abbreviations: The major findings of the search are: (1) Acute and subacute carbon monoxide exposures result in a large number of symptoms affecting the brain, kidneys, respiratory system, retina, and motor functions. (2) Acute and subacute carbon monoxide (CO) poisonings have been misdiagnosed on many occasions. (3) Very few systematic investigations have been made into the frequency and consequences of carbon monoxide poisonings.

  18. Recycled diesel carbon nanoparticles for nanostructured battery anodes

    Science.gov (United States)

    Chen, Yuming; Liu, Chang; Sun, Xiaoxuan; Ye, Han; Cheung, Chunshun; Zhou, Limin

    2015-02-01

    Considerable attention has been devoted to using rational nanostructure design to address critical carbonaceous anode material issues for next-generation lithium-ion batteries (LIBs). However, the fabrication of nanostructured carbonaceous anode materials often involves complex processes and expensive starting materials. Diesel engine is an important source of nanostructured carbon particles with diameters ranging 20 nm-60 nm suspended in air, resulting in a serious scourge of global climate and a series of diseases such as lung cancer, asthma, and cardiovascular disease. Here, we show that diesel carbon nanoparticles collected from diesel engines can be chemically activated to create a porous structure. The resulting nanostructured carbon electrodes have a high specific capacity of 936 mAh g-1 after 40 cycles at 0.05 A/g, and excellent cycle stability while retaining a capacity of ∼210 mAh g-1 after 1200 cycles at 5 A/g. As recycled diesel carbon nanoparticles are readily available due to the several billion tons of diesel fuel consumed every year by diesel engines, their use represents an exciting source for nanostructured carbonaceous anode materials for high-performance LIBs and improves our environment and health.

  19. Synthesis and characterization of carbon nanotubes decorated with platinum nanoparticles

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2010-04-01

    Full Text Available Purpose: In presented work results of synthesis of carbon nanotubes decorated with platinum nanoparticles by organic colloidal process as an example of direct formation of nanoparticles onto CNTs are reported.Design/methodology/approach: CNT were grown by chemical vapour deposition (CVD by the catalytic decomposition of CO. To improve metal deposition onto CNTs the purification procedure with a mixture of concentrated HNO3–H2SO4 and H2O2 reduction reagent was applied. CNT–nanocrystal composite was fabricated by direct deposition of nanoparticles onto the surface of CNTs. Chemical composition and crystallographic structure of the obtained Pt/CNT composites were confirmed by energy dispersive X-ray spectroscopy (EDS and by X-ray diffraction (XRD measurements, while transmission (TEM and scanning electron microscopy (SEM were used for characterization of the morphology of composite as well as the distribution of nanocrystals on the CNTs surfaces.Findings: High efficiency of proposed method was confirmed as well as possibility of the coating of Pt nanoparticles onto CNTs, without aggregation of these particles.Research limitations/implications: Many others noble metals such as palladium, platinum, gold and iridium can be used for deposition on the CNTs using described procedure.Originality/value: Obtained material can be employed in constructing various electrochemical sensors. As a result of increasing of the surface area of Pt caused by the reduction of the size of used particles, fabricated sensor may be characterized by higher sensitivity.

  20. EPR characterisation of platinum nanoparticle functionalised carbon nanotube hybrid materials.

    Science.gov (United States)

    Dennany, Lynn; Sherrell, Peter; Chen, Jun; Innis, Peter C; Wallace, Gordon G; Minett, Andrew I

    2010-04-28

    The use of nanostructured carbon materials as electrodes for energy storage and conversion is an expanding area of research in recent years. Herein, platinum nanoparticles have been deposited onto both multi-walled and single-walled carbon nanotubes (CNTs) via a microwave assisted polyol reduction method. This interaction has been probed with electron paramagnetic resonance (EPR) and Raman spectroscopies to elucidate the charge/electron transfer interactions between the Pt nanoparticles and the CNTs. Observed shifts in the g factors of the CNTs are indicative of such an electronic interaction, strongly suggesting the covalent attachment of the nanoparticles to the carboxylic groups on the CNTs, formed during the microwave-assisted reduction process. The Pt decorated CNTs show a dramatic increase in electrochemical behaviour in terms of high reversible capacity and relatively stable cycle performance compared to unmodified CNTs increasing their applicability in energy storage devices. For instance, significant increases in the electrochemical double layer capacitance are observed for the CNT-NP composite electrode. PMID:20379504

  1. Laser-generated plasma by carbon nanoparticles embedded into polyethylene

    Science.gov (United States)

    Torrisi, L.; Ceccio, G.; Cutroneo, M.

    2016-05-01

    Carbon nanoparticles have been embedded into polyethylene at different concentrations by using chemical-physical processes. The synthesized material was characterized in terms of physical modifications concerning the mechanical, compositional and optical properties. Obtained flat targets have been irradiated by Nd:YAG laser at intensities of the order of 1010 W/cm2 in order to generate non-equilibrium plasma in vacuum. The laser-matter interaction produces charge separation effects with consequent acceleration of protons and carbon ions. Plasma was characterized using time-of-flight measurements of the accelerated ions. Applications of the produced targets in order to generate carbon ion beams from laser-generated plasma are presented and discussed.

  2. Thermal stability of carbon nanotubes probed by anchored tungsten nanoparticles

    Directory of Open Access Journals (Sweden)

    Xianlong Wei, Ming-Sheng Wang, Yoshio Bando and Dmitri Golberg

    2011-01-01

    Full Text Available The thermal stability of multiwalled carbon nanotubes (CNTs was studied in high vacuum using tungsten nanoparticles as miniaturized thermal probes. The particles were placed on CNTs inside a high-resolution transmission electron microscope equipped with a scanning tunneling microscope unit. The setup allowed manipulating individual nanoparticles and heating individual CNTs by applying current to them. CNTs were found to withstand high temperatures, up to the melting point of 60-nm-diameter W particles (~3400 K. The dynamics of W particles on a hot CNT, including particle crystallization, quasimelting, melting, sublimation and intradiffusion, were observed in real time and recorded as a video. Graphite layers reel off CNTs when melted or premelted W particles revolve along the tube axis.

  3. Comparison of Nanoparticle Exposures Between Fumed and Sol-gel Nano-silica Manufacturing Facilities

    OpenAIRE

    OH, Sewan; KIM, Boowook; KIM, Hyunwook

    2014-01-01

    Silica nanoparticles (SNPs) are widely used all around the world and it is necessary to evaluate appropriate risk management measures. An initial step in this process is to assess worker exposures in their current situation. The objective of this study was to compare concentrations and morphologic characteristics of fumed (FS) and sol-gel silica nanoparticles (SS) in two manufacturing facilities. The number concentration (NC) and particle size were measured by a real-time instrument. Airborne...

  4. Comparative effects of dissolved copper and copper oxide nanoparticle exposure to the sea anemone, Exaiptasia pallida

    International Nuclear Information System (INIS)

    Highlights: • Differences between CuO NP and CuCl2 exposure were characterized. • Copper accumulation in E. pallida was concentration-dependent. • E. pallida exposed to CuCl2 accumulated higher copper tissue burdens. • The oxidative stress response was greater in E. pallida exposed to CuO NP. • Both forms of copper inhibited CA activity in E. pallida. - Abstract: Increasing use of metal oxide nanoparticles (NP) by various industries has resulted in substantial output of these NP into aquatic systems. At elevated concentrations, NP may interact with and potentially affect aquatic organisms. Environmental implications of increased NP use are largely unknown, particularly in marine systems. This research investigated and compared the effects of copper oxide (CuO) NP and dissolved copper, as copper chloride (CuCl2), on the sea anemone, Exaiptasia pallida. Sea anemones were collected over 21 days and tissue copper accumulation and activities of the enzymes: catalase, glutathione peroxidase, glutathione reductase, and carbonic anhydrase were quantified. The size and shape of CuO NP were observed using a ecanning electron microscope (SEM) and the presence of copper was confirmed by using Oxford energy dispersive spectroscopy systems (EDS/EDX). E. pallida accumulated copper in their tissues in a concentration- and time-dependent manner, with the animals exposed to CuCl2 accumulating higher tissue copper burdens than those exposed to CuO NP. As a consequence of increased copper exposure, as CuO NP or CuCl2, anemones increased activities of all of the antioxidant enzymes measured to some degree, and decreased the activity of carbonic anhydrase. Anemones exposed to CuO NP generally had higher anti-oxidant enzyme activities than those exposed to the same concentrations of CuCl2. This study is useful in discerning differences between CuO NP and dissolved copper exposure and the findings have implications for exposure of aquatic organisms to NP in the environment

  5. Comparative effects of dissolved copper and copper oxide nanoparticle exposure to the sea anemone, Exaiptasia pallida

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Samreen; Goddard, Russell H.; Bielmyer-Fraser, Gretchen K., E-mail: gkbielmyer@valdosta.edu

    2015-03-15

    Highlights: • Differences between CuO NP and CuCl{sub 2} exposure were characterized. • Copper accumulation in E. pallida was concentration-dependent. • E. pallida exposed to CuCl{sub 2} accumulated higher copper tissue burdens. • The oxidative stress response was greater in E. pallida exposed to CuO NP. • Both forms of copper inhibited CA activity in E. pallida. - Abstract: Increasing use of metal oxide nanoparticles (NP) by various industries has resulted in substantial output of these NP into aquatic systems. At elevated concentrations, NP may interact with and potentially affect aquatic organisms. Environmental implications of increased NP use are largely unknown, particularly in marine systems. This research investigated and compared the effects of copper oxide (CuO) NP and dissolved copper, as copper chloride (CuCl{sub 2}), on the sea anemone, Exaiptasia pallida. Sea anemones were collected over 21 days and tissue copper accumulation and activities of the enzymes: catalase, glutathione peroxidase, glutathione reductase, and carbonic anhydrase were quantified. The size and shape of CuO NP were observed using a ecanning electron microscope (SEM) and the presence of copper was confirmed by using Oxford energy dispersive spectroscopy systems (EDS/EDX). E. pallida accumulated copper in their tissues in a concentration- and time-dependent manner, with the animals exposed to CuCl{sub 2} accumulating higher tissue copper burdens than those exposed to CuO NP. As a consequence of increased copper exposure, as CuO NP or CuCl{sub 2}, anemones increased activities of all of the antioxidant enzymes measured to some degree, and decreased the activity of carbonic anhydrase. Anemones exposed to CuO NP generally had higher anti-oxidant enzyme activities than those exposed to the same concentrations of CuCl{sub 2}. This study is useful in discerning differences between CuO NP and dissolved copper exposure and the findings have implications for exposure of aquatic

  6. Development of a dose-controlled multiculture cell exposure chamber for efficient delivery of airborne and engineered nanoparticles

    International Nuclear Information System (INIS)

    In order to study the various health influencing parameters related to engineered nanoparticles as well as to soot emitted by Diesel engines, there is an urgent need for appropriate sampling devices and methods for cell exposure studies that simulate the respiratory system and facilitate associated biological and toxicological tests. The objective of the present work was the further advancement of a Multiculture Exposure Chamber (MEC) into a dose-controlled system for efficient delivery of nanoparticles to cells. It was validated with various types of nanoparticles (Diesel engine soot aggregates, engineered nanoparticles for various applications) and with state-of-the-art nanoparticle measurement instrumentation to assess the local deposition of nanoparticles on the cell cultures. The dose of nanoparticles to which cell cultures are being exposed was evaluated in the normal operation of the in vitro cell culture exposure chamber based on measurements of the size specific nanoparticle collection efficiency of a cell free device. The average efficiency in delivering nanoparticles in the MEC was approximately 82%. The nanoparticle deposition was demonstrated by Transmission Electron Microscopy (TEM). Analysis and design of the MEC employs Computational Fluid Dynamics (CFD) and true to geometry representations of nanoparticles with the aim to assess the uniformity of nanoparticle deposition among the culture wells. Final testing of the dose-controlled cell exposure system was performed by exposing A549 lung cell cultures to fluorescently labeled nanoparticles. Delivery of aerosolized nanoparticles was demonstrated by visualization of the nanoparticle fluorescence in the cell cultures following exposure. Also monitored was the potential of the aerosolized nanoparticles to generate reactive oxygen species (ROS) (e.g. free radicals and peroxides generation), thus expressing the oxidative stress of the cells which can cause extensive cellular damage or damage on DNA.

  7. Potential inhalation exposure and containment efficiency when using hoods for handling nanoparticles

    International Nuclear Information System (INIS)

    Inhalation exposure to airborne nanoparticles (NPs) has been reported during manual activities using typical fume hoods. This research studied potential inhalation exposure associated with the manual handling of NPs using two new nanoparticle-handling enclosures and two biological safety cabinets, and discussed the ability to contain NPs in the hoods to reduce environmental release and exposure. Airborne concentrations of 5 nm to 20 μm diameter particles were measured while handling nanoalumina particles in various ventilated enclosures. Tests were conducted using two handling conditions and concentrations were measured using real-time particle counters, and particles were collected on transmission electron microscope grids to determine particle morphology and elemental composition. Airflow patterns were characterized visually using a laser-light sheet and fog. The average number concentration increase at breathing zone outside the enclosure was less than 1,400 particle/cm3 for each particle size at all tested conditions and the estimated overall mass concentration was about 83 μg/m3 which was less than the dosage of typical nanoparticle inhalation exposure studies. The typical front-to-back airflow was used in the studied hoods, which could potentially induce reverse turbulence in the wake region. However, containment of NPs using studied hoods was demonstrated with excellent performance. Smoke tests showed that worker’s hand motion could potentially cause nanoparticle escape. The challenge of front-to-back airflow can be partially overcome by gentle motion, low face velocity, and front exhaust to reduce nanoparticle escape

  8. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms.

    Science.gov (United States)

    Murugan, Kadarkarai; Nataraj, Devaraj; Madhiyazhagan, Pari; Sujitha, Vasu; Chandramohan, Balamurugan; Panneerselvam, Chellasamy; Dinesh, Devakumar; Chandirasekar, Ramachandran; Kovendan, Kalimuthu; Suresh, Udaiyan; Subramaniam, Jayapal; Paulpandi, Manickam; Vadivalagan, Chithravel; Rajaganesh, Rajapandian; Wei, Hui; Syuhei, Ban; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-03-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC50 (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same

  9. Synthesis and Characterization of Carbon Nanotubes Decorated with Gold Nanoparticles

    International Nuclear Information System (INIS)

    In presented work we report results of simple and viable method for producing Au/CNT composites. Chemical composition and crystallographic structure of the Au/CNT composites was confirmed by X-ray diffraction measurements, while transmission and scanning electron microscopy were used to characterize the morphology of nanocrystals as well as the distribution of nanocrystals in the composite. The obtained particles with relatively small diameter (less than 9 nm) were found to be spatially well dispersed on the carbon nanotubes. The density of attached Au-nanoparticles is not sufficient, and cannot be improved by simple increasing gold loading. (authors)

  10. Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

    NARCIS (Netherlands)

    Koelmans, A.A.; Nowack, B.; Wiesner, M.

    2009-01-01

    In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to agg

  11. Carbon-coated nanoparticle superlattices for energy applications

    Science.gov (United States)

    Li, Jun; Yiliguma, Affa; Wang, Yifei; Zheng, Gengfeng

    2016-07-01

    Nanoparticle (NP) superlattices represent a unique material architecture for energy conversion and storage. Recent reports on carbon-coated NP superlattices have shown exciting electrochemical properties attributed to their rationally designed compositions and structures, fast electron transport, short diffusion length, and abundant reactive sites via enhanced coupling between close-packed NPs, which are distinctive from their isolated or disordered NP or bulk counterparts. In this minireview, we summarize the recent developments of highly-ordered and interconnected carbon-coated NP superlattices featuring high surface area, tailorable and uniform doping, high conductivity, and structure stability. We then introduce the precisely-engineered NP superlattices by tuning/studying specific aspects, including intermetallic structures, long-range ordering control, and carbon coating methods. In addition, these carbon-coated NP superlattices exhibit promising characteristics in energy-oriented applications, in particular, in the fields of lithium-ion batteries, fuel cells, and electrocatalysis. Finally, the challenges and perspectives are discussed to further explore the carbon-coated NP superlattices for optimized electrochemical performances.

  12. Carbon-coated nanoparticle superlattices for energy applications.

    Science.gov (United States)

    Li, Jun; Yiliguma; Wang, Yifei; Zheng, Gengfeng

    2016-08-14

    Nanoparticle (NP) superlattices represent a unique material architecture for energy conversion and storage. Recent reports on carbon-coated NP superlattices have shown exciting electrochemical properties attributed to their rationally designed compositions and structures, fast electron transport, short diffusion length, and abundant reactive sites via enhanced coupling between close-packed NPs, which are distinctive from their isolated or disordered NP or bulk counterparts. In this minireview, we summarize the recent developments of highly-ordered and interconnected carbon-coated NP superlattices featuring high surface area, tailorable and uniform doping, high conductivity, and structure stability. We then introduce the precisely-engineered NP superlattices by tuning/studying specific aspects, including intermetallic structures, long-range ordering control, and carbon coating methods. In addition, these carbon-coated NP superlattices exhibit promising characteristics in energy-oriented applications, in particular, in the fields of lithium-ion batteries, fuel cells, and electrocatalysis. Finally, the challenges and perspectives are discussed to further explore the carbon-coated NP superlattices for optimized electrochemical performances. PMID:27432112

  13. One step synthesis of Al/N co-doped carbon nanoparticles with enhanced photoluminescence

    International Nuclear Information System (INIS)

    In a typical synthesis, luminescent carbon nanoparticles were synthesized via hydrothermal oxidation of glucose in deionized water. Here we reported the photoluminescence of the carbon nanoparticles greatly enhanced when reacted with Al(NO3)3 for the first time, the resulted carbon dots have appropriate spherical morphology, uniform size and good dispersion. The carbon nanoparticles can exhibit excitation-dependent photoluminescence behavior and emit bright green photoluminescence under UV excitation, which might provide a potential application for carbon dots in other extensive fields. - Highlights: • One step synthesis of Al/N co-doped carbon nanoparticles via a hydrothermal method. • The Al/N co-doped carbon dots possessed higher luminescence than the primordial one. • The cause for the enhanced photoluminescence was investigated and discussed

  14. One step synthesis of Al/N co-doped carbon nanoparticles with enhanced photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Li; Ruan, Fengping; Lv, Ting; Liu, Yanqiang; Deng, Degang, E-mail: dengdegang@cjlu.edu.cn; Zhao, Shilong; Wang, Huanping; Xu, Shiqing, E-mail: sxucjlu@hotmail.com

    2015-02-15

    In a typical synthesis, luminescent carbon nanoparticles were synthesized via hydrothermal oxidation of glucose in deionized water. Here we reported the photoluminescence of the carbon nanoparticles greatly enhanced when reacted with Al(NO{sub 3}){sub 3} for the first time, the resulted carbon dots have appropriate spherical morphology, uniform size and good dispersion. The carbon nanoparticles can exhibit excitation-dependent photoluminescence behavior and emit bright green photoluminescence under UV excitation, which might provide a potential application for carbon dots in other extensive fields. - Highlights: • One step synthesis of Al/N co-doped carbon nanoparticles via a hydrothermal method. • The Al/N co-doped carbon dots possessed higher luminescence than the primordial one. • The cause for the enhanced photoluminescence was investigated and discussed.

  15. Cobalt magnetic nanoparticles embedded in carbon matrix: biofunctional validation

    International Nuclear Information System (INIS)

    Carbon nanostructures and nanocomposites display versatile allotropic morphologies, physico-chemical properties and have a wide range of applications in mechanics, electronics, biotechnology, structural material, chemical processing, and energy management. In this study we report the synthesis, characterization, and biotechnological application of cobalt magnetic nanoparticles, with diameter approximately 15–40 nm, embedded in carbon structure (Co/C-MN). A single-step chemical process was used in the synthesis of the Co/C-MN. The Co/C-MN has presented superparamagnetic behavior at room temperature an essential property for immunoseparation assays carried out here. To stimulate interactions between proteins and Co/C-MN, this nanocomposite was functionalized with acrylic acid (AA). We have showed the bonding of different proteins onto Co/C-AA surface using immunofluorescence assay. A Co/C-AA coated with monoclonal antibody anti-pathogenic Leptospira spp. was able to capture leptospires, suggesting that it could be useful in immunoseparation assays.

  16. Cobalt magnetic nanoparticles embedded in carbon matrix: biofunctional validation

    Energy Technology Data Exchange (ETDEWEB)

    Krolow, Matheus Z., E-mail: matheuskrolow@ifsul.edu.br [Universidade Federal de Pelotas, Engenharia de Materiais, Centro de Desenvolvimento Tecnologico (Brazil); Monte, Leonardo G.; Remiao, Mariana H.; Hartleben, Claudia P.; Moreira, Angela N.; Dellagostin, Odir A. [Universidade Federal de Pelotas, Nucleo de Biotecnologia, Centro de Desenvolvimento Tecnologico (Brazil); Piva, Evandro [Universidade Federal de Pelotas, Faculdade de Odontologia (Brazil); Conceicao, Fabricio R. [Universidade Federal de Pelotas, Nucleo de Biotecnologia, Centro de Desenvolvimento Tecnologico (Brazil); Carreno, Neftali L. V. [Universidade Federal de Pelotas, Engenharia de Materiais, Centro de Desenvolvimento Tecnologico (Brazil)

    2012-09-15

    Carbon nanostructures and nanocomposites display versatile allotropic morphologies, physico-chemical properties and have a wide range of applications in mechanics, electronics, biotechnology, structural material, chemical processing, and energy management. In this study we report the synthesis, characterization, and biotechnological application of cobalt magnetic nanoparticles, with diameter approximately 15-40 nm, embedded in carbon structure (Co/C-MN). A single-step chemical process was used in the synthesis of the Co/C-MN. The Co/C-MN has presented superparamagnetic behavior at room temperature an essential property for immunoseparation assays carried out here. To stimulate interactions between proteins and Co/C-MN, this nanocomposite was functionalized with acrylic acid (AA). We have showed the bonding of different proteins onto Co/C-AA surface using immunofluorescence assay. A Co/C-AA coated with monoclonal antibody anti-pathogenic Leptospira spp. was able to capture leptospires, suggesting that it could be useful in immunoseparation assays.

  17. Facile Synthesis of Calcium Carbonate Nanoparticles from Cockle Shells

    Directory of Open Access Journals (Sweden)

    Kh. Nurul Islam

    2012-01-01

    Full Text Available A simple and low-cost method for the synthesis of calcium carbonate nanoparticles from cockle shells was described. Polymorphically, the synthesized nanoparticles were aragonites which are biocompatible and thus frequently used in the repair of fractured bone and development of advanced drug delivery systems, tissue scaffolds and anticarcinogenic drugs. The rod-shaped and pure aragonite particles of 30±5 nm in diameter were reproducibly synthesized when micron-sized cockle shells powders were mechanically stirred for 90 min at room temperature in presence of a nontoxic and nonhazardous biomineralization catalyst, dodecyl dimethyl betaine (BS-12. The findings were verified using a combination of analytical techniques such as variable pressure scanning electron microscopy (VPSEM, transmission electron microscopy (TEM, Fourier transmission infrared spectroscopy (FT-IR, X-ray diffraction spectroscopy (XRD, and energy dispersive X-ray analyser (EDX. The reproducibility and low cost of the method suggested that it could be used in industry for the large scale synthesis of aragonite nanoparticles from cockle shells, a low cost and easily available natural resource.

  18. Catalytic oxidation of carbon monoxide over supported palladium nanoparticles

    Science.gov (United States)

    Soni, Keshav Chand; Krishna, R.; Chandra Shekar, S.; Singh, Beer

    2016-01-01

    Catalytic oxidation of CO with ozone had been studied over Al2O3 and SiO2 supported Pd nanoparticles which was synthesized by two different methods. The polyol method mainly resulted in highly dispersed Pd particles on the support, while the impregnation method resulted in agglomeration Pd particles on the support. Supported Pd nanoparticles synthesized from PdCl2 in the presence of poly ( N-vinylpyrrolidone) (PVP) by chemical reduction. The catalysts were characterized by X-ray diffraction, N2 BET surface area, pore size distributions, CO chemisorption, TEM and H2-temperature programmed reduction. The physico-chemical properties were well correlated with activity data. Characterizations of XRD and TEM show that the surface Pd nanoparticles are highly dispersed over Al2O3 and SiO2. The catalytic activity was dependent upon ozone/CO ratio, contact times, and the reaction temperature. The extent of carbon monoxide oxidation was proportional to the catalytically ozone decomposition. The PVP synthesized Pd/A2O3 catalyst had been found to be highly active for complete CO removal at room temperature. The higher activity of the nanocatalyst was attributed to small particle size and higher dispersion of Pd over support.

  19. Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

    International Nuclear Information System (INIS)

    Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher's breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher's breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face velocity

  20. Combustion-derived nanoparticles: A review of their toxicology following inhalation exposure

    Directory of Open Access Journals (Sweden)

    Mills Nicholas

    2005-10-01

    Full Text Available Abstract This review considers the molecular toxicology of combustion-derived nanoparticles (CDNP following inhalation exposure. CDNP originate from a number of sources and in this review we consider diesel soot, welding fume, carbon black and coal fly ash. A substantial literature demonstrates that these pose a hazard to the lungs through their potential to cause oxidative stress, inflammation and cancer; they also have the potential to redistribute to other organs following pulmonary deposition. These different CDNP show considerable heterogeneity in composition and solubility, meaning that oxidative stress may originate from different components depending on the particle under consideration. Key CDNP-associated properties of large surface area and the presence of metals and organics all have the potential to produce oxidative stress. CDNP may also exert genotoxic effects, depending on their composition. CDNP and their components also have the potential to translocate to the brain and also the blood, and thereby reach other targets such as the cardiovascular system, spleen and liver. CDNP therefore can be seen as a group of particulate toxins unified by a common mechanism of injury and properties of translocation which have the potential to mediate a range of adverse effects in the lungs and other organs and warrant further research.

  1. A synthetic DNA motor that transports nanoparticles along carbon nanotubes

    Science.gov (United States)

    Cha, Tae-Gon; Pan, Jing; Chen, Haorong; Salgado, Janette; Li, Xiang; Mao, Chengde; Choi, Jong Hyun

    2014-01-01

    Intracellular protein motors have evolved to perform specific tasks critical to the function of cells such as intracellular trafficking and cell division. Kinesin and dynein motors, for example, transport cargoes in living cells by walking along microtubules powered by adenosine triphosphate hydrolysis. These motors can make discrete 8 nm centre-of-mass steps and can travel over 1 µm by changing their conformations during the course of adenosine triphosphate binding, hydrolysis and product release. Inspired by such biological machines, synthetic analogues have been developed including self-assembled DNA walkers that can make stepwise movements on RNA/DNA substrates or can function as programmable assembly lines. Here, we show that motors based on RNA-cleaving DNA enzymes can transport nanoparticle cargoes--CdS nanocrystals in this case--along single-walled carbon nanotubes. Our motors extract chemical energy from RNA molecules decorated on the nanotubes and use that energy to fuel autonomous, processive walking through a series of conformational changes along the one-dimensional track. The walking is controllable and adapts to changes in the local environment, which allows us to remotely direct `go' and `stop' actions. The translocation of individual motors can be visualized in real time using the visible fluorescence of the cargo nanoparticle and the near-infared emission of the carbon-nanotube track. We observed unidirectional movements of the molecular motors over 3 µm with a translocation velocity on the order of 1 nm min-1 under our experimental conditions.

  2. Management of Occupational Exposure to Engineered Nanoparticles Through a Chance-Constrained Nonlinear Programming Approach

    OpenAIRE

    Feng-Lin Yang; Shu-Shen Zhang; Zhi Chen; Yuan Yuan; Yu Chen

    2013-01-01

    Critical environmental and human health concerns are associated with the rapidly growing fields of nanotechnology and manufactured nanomaterials (MNMs). The main risk arises from occupational exposure via chronic inhalation of nanoparticles. This research presents a chance-constrained nonlinear programming (CCNLP) optimization approach, which is developed to maximize the nanaomaterial production and minimize the risks of workplace exposure to MNMs. The CCNLP method integrates nonlinear progra...

  3. Legionella pneumophila Transcriptional Response following Exposure to CuO Nanoparticles

    OpenAIRE

    Lu, Jingrang; Struewing, Ian; Buse, Helen Y.; Kou, Jiahui; Shuman, Howard A.; Faucher, Sébastien P.; Ashbolt, Nicholas J.

    2013-01-01

    Copper ions are an effective antimicrobial agent used to control Legionnaires' disease and Pontiac fever arising from institutional drinking water systems. Here, we present data on an alternative bactericidal agent, copper oxide nanoparticles (CuO-NPs), and its efficacy on Legionella pneumophila. In broth cultures, the CuO-NPs caused growth inhibition, which appeared to be concentration and exposure time dependent. The transcriptomic response of L. pneumophila to CuO-NP exposure was investiga...

  4. Daily personal exposure to black carbon: A pilot study

    Science.gov (United States)

    Williams, Ryan D.; Knibbs, Luke D.

    2016-05-01

    Continuous personal monitoring is the benchmark for air pollution exposure assessment. Black carbon (BC) is a strong marker of primary combustion like vehicle and biomass emissions. There have been few studies that quantified daily personal BC exposure and the contribution that different microenvironments make to it. In this pilot study, we used a portable aethalometer to measure BC concentrations in an individual's breathing zone at 30-s intervals while he performed his usual daily activities. We used a GPS and time-activity diary to track where he spent his time. We performed twenty 24-h measurements, and observed an arithmetic mean daily exposure concentration of 603 ng/m3. We estimated that changing commute modes from bus to train reduced the 24-h mean BC exposure concentration by 29%. Switching from open windows to closed windows and recirculated air in a car led to a reduction of 32%. Living in a home without a wood-fired heater caused a reduction of 50% compared with a wood-heated home. Our preliminary findings highlight the potential utility of simple approaches to reduce a person's daily BC exposure.

  5. The occurrence of hazardous volatile elements and nanoparticles in Bulgarian coal fly ashes and the effect on human health exposure

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis F.O., E-mail: lfsoliveira@univates.br [Centro Universitario Univates, Pro Reitoria de Pesquisa Estensao e Pos Graduacao, Programa de Pos Graduacao Ambiente e Desenvolvimento (Brazil); Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development - IPADHC, Capivari de Baixo, Santa Catarina (Brazil); DaBoit, Katia [Department of Environmental Medicine, Catarinense Institute of Environmental Research and Human Development - IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Sampaio, Carlos H. [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Goncalves, 9500, Bairro Agronomia, CEP: 91501-970, Porto Alegre - RS (Brazil); Jasper, Andre [Centro Universitario Univates, Pro Reitoria de Pesquisa Estensao e Pos Graduacao, Programa de Pos Graduacao Ambiente e Desenvolvimento (Brazil); Andrade, Maria L. [Department of Plant Biology and Soil Science, University of Vigo, 36310 Vigo (Spain); Kostova, Irena J. [Sofia University ' St. Kliment Ohridski' , Department of Geology, Paleontology and Fossil Fuels, 15, Tzar Osvoboditel Blvd., 1000 Sofia (Bulgaria); and others

    2012-02-01

    Low-rank, high-mineral matter Bulgarian coals were studied using a variety of chemical, optical, and electron beam methods. The larger fly ash carbon phases include charred carbons in contrast to coked carbons present in the fly ashes of bituminous-coal-derived fly ashes. Nanoscale carbons include multi-walled carbon nanotubes (MWCNTs) encapsulating Hg, Se, and As, among other elements. In addition to the glass which dominates the fly ash, relatively coarse 'rock fragments', consisting of an unmelted to partially melted core surrounded by a glassy rim, are present in the fly ash. Nano-scale minerals can contain hazardous elements and, along with metal-bearing multiwalled nanotubes, can be a path for the entry of hazardous particles into the lungs and other organs. Highlights: Black-Right-Pointing-Pointer We model Bulgarian power plants which have regulated minerals nanoparticles can contain hazardous elements. Black-Right-Pointing-Pointer We study changes in the level of information about nanominerals importance and the effect on human health exposure. Black-Right-Pointing-Pointer Increasing information will increase quality if power plants procedures are similar.

  6. Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging

    Science.gov (United States)

    Oza, Goldie; Ravichandran, M.; Merupo, Victor-Ishrayelu; Shinde, Sachin; Mewada, Ashmi; Ramirez, Jose Tapia; Velumani, S.; Sharon, Madhuri; Sharon, Maheshwar

    2016-02-01

    A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent.

  7. Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging.

    Science.gov (United States)

    Oza, Goldie; Ravichandran, M; Merupo, Victor-Ishrayelu; Shinde, Sachin; Mewada, Ashmi; Ramirez, Jose Tapia; Velumani, S; Sharon, Madhuri; Sharon, Maheshwar

    2016-01-01

    A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent. PMID:26905737

  8. The uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna under chronic exposure scenarios.

    Science.gov (United States)

    Adam, Nathalie; Leroux, Frédéric; Knapen, Dries; Bals, Sara; Blust, Ronny

    2015-01-01

    In this study, the uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna was tested. Daphnids were exposed during 10 days to sublethal concentrations of ZnO and CuO nanoparticles and corresponding metal salts (ZnCl₂ and CuCl₂.2H₂O), after which they were transferred to unexposed medium for another 10 days. At different times during the exposure and none-exposure, the total and internal zinc or copper concentration of the daphnids was determined and the nanoparticles were localized in the organism using electron microscopy. The exposure concentrations were characterized by measuring the dissolved, nanoparticle and aggregated fraction in the medium. The results showed that the ZnO nanoparticles quickly dissolved after addition to the medium. Contrarily, only a small fraction (corresponding to the dissolved metal salt) of the CuO nanoparticles dissolved, while most of these nanoparticles formed large aggregates. Despite an initial increase in zinc and copper concentration during the first 48 h to 5 day exposure, the body concentration reached a plateau level that was comparable for the ZnO nanoparticles and ZnCl₂, but much higher for the CuO nanoparticles (with visible aggregates accumulating in the gut) than CuCl₂.2H₂O. During the remaining exposure and subsequent none-exposure phase, the zinc and copper concentration decreased fast to concentrations comparable with the unexposed daphnids. The results indicate that D. magna can regulate its internal zinc and copper concentration after exposure to ZnO and CuO nanoparticles, similar as after exposure to metal salts. The combined dissolution, accumulation and toxicity results confirm that the toxicity of ZnO and CuO nanoparticles is caused by the dissolved fraction. PMID:25462733

  9. Screening of silver nanoparticles containing carbonized yeast cells for adsorption of few long-lived active radionuclides

    International Nuclear Information System (INIS)

    The present study involves the screening of silver nanoparticles containing carbonized yeast cells isolated from coconut cell sap for efficient adsorption of few long lived radionuclides like 137Cs55, 60Co27, 106Ru44, 239Pu94 and 241Am95. Yeast cells containing silver nanoparticles produced through biological reduction were subjected to carbonization (400 deg C for 1 h) at atmospheric conditions and their properties were analyzed using fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscope. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells without silver exposure (CCY) did not contain any particles on its surface. The efficiency of CSY and CCY towards the radionuclide adsorption was studied in batch mode at fixed contact time, concentration, and at its native pH. CSY was efficient in removal of 239Pu94 (76.75%) and 106Ru44 (54.73%) whereas CCY showed efficient removal only for 241Am95 (62.89%). Both the adsorbents did not show any retention with respect to 60Co27 and 137Cs55. Based on the experimental data, decontamination factor and distribution coefficient (Kd) were calculated and, from the values, it was observed that these adsorbents have greater potential to adsorb radionuclides. (author)

  10. Decoration of Silver Nanoparticles on Multiwalled Carbon Nanotubes: Antibacterial Mechanism and Ultrastructural Analysis

    OpenAIRE

    Ngo Xuan Dinh; Nguyen Van Quy; Tran Quang Huy; Anh-Tuan Le

    2015-01-01

    Recently, development of carbon nanocomposites composed of carbon nanostructures and metal nanoparticles has attracted much interests because of their large potential for technological applications such as catalyst, sensor, biomedicine, and disinfection. In this work, we established a simple chemistry method to synthesize multiwalled carbon nanotubes (MWCNTs) decorated with silver nanoparticles (Ag-NPs) using a modified photochemical reaction (Tollens process). The formation and interaction o...

  11. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    OpenAIRE

    Kumaresa P S Prasad, Dattatray S Dhawale, Thiripuranthagan Sivakumar, Salem S Aldeyab, Javaid S M Zaidi, Katsuhiko Ariga and Ajayan Vinu

    2011-01-01

    We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM). XRD r...

  12. Pulsed Plasma Synthesis of Iron and Nickel Nanoparticles Coated by Carbon for Medical Applications

    Science.gov (United States)

    Abdullaeva, Zhypargul; Omurzak, Emil; Iwamoto, Chihiro; Ihara, Hirotaka; Subban Ganapathy, Hullathy; Sulaimankulova, Saadat; Koinuma, Michio; Mashimo, Tsutomu

    2013-01-01

    Fe and Ni magnetic nanoparticles coated by carbon were synthesized between the Fe-Fe and Ni-Ni metal electrodes, submerged in ethanol using pulsed plasma in a liquid method. Iron coated carbon (Fe@C) nanoparticles have an average size of 32 nm, and Ni@C nanoparticles are 40 nm. Obtained samples exhibit a well-defined crystalline structure of the inner Fe and Ni cores, encapsulated in the graphitic carbon coatings. Cytotoxicity studies performed on the MCF-7 (breast cancer) cell line showed small toxicity about 88-74% at 50 µg/mL of Fe@C and Ni@C nanoparticles, which can be significant criteria for use them in medical cancer treatment. In addition, appropriate sizes, good magnetic properties and well-organized graphitic carbon coatings are highlight merits of Fe@C and Ni@C nanoparticles synthesized by pulsed plasma.

  13. Transformation of crystalline starch nanoparticles into highly luminescent carbon nanodots: Toxicity studies and their applications.

    Science.gov (United States)

    Sonthanasamy, Regina Sisika A; Ahmad, Wan Yaacob Wan; Fazry, Shazrul; Hassan, Nurul I; Lazim, Azwan Mat

    2016-02-10

    Being abundant in many tropical part of the world, Dioscorea sp. as food is limited due to its toxicity. However polysaccharides derive from these tubers could be important for other applications. Here we developed a Highly Luminescent Carbon Nanodots (C-dots) via acid hydrolysis of Gadong starch (GS). The hydrolysis rate of GS increased from 49% to 86% within 7 days while the X-ray diffraction showed the native GS particle is a C-crystalline type. The GS particles were either round or oval with diameters ranging from 50-90 nm. Further acid dehydration and surface oxidation reduced the size of GS nanoparticles to 6-25 nm. The C-dots produced a fluorescent emission at wavelength 441 nm. Toxicity tests demonstrate that zebrafish embryo were able to tolerate the C-dots for 48 h after exposure. This study has successfully demonstrated a novel approach of converting GS into excellent fluorescent C-dot. PMID:26686155

  14. Occupational exposure limit for silver nanoparticles: considerations on the derivation of a general health-based value.

    Science.gov (United States)

    Weldon, Brittany A; M Faustman, Elaine; Oberdörster, Günter; Workman, Tomomi; Griffith, William C; Kneuer, Carsten; Yu, Il Je

    2016-09-01

    With the increased production and widespread commercial use of silver nanoparticles (AgNPs), human and environmental exposures to silver nanoparticles are inevitably increasing. In particular, persons manufacturing and handling silver nanoparticles and silver nanoparticle containing products are at risk of exposure, potentially resulting in health hazards. While silver dusts, consisting of micro-sized particles and soluble compounds have established occupational exposure limits (OELs), silver nanoparticles exhibit different physicochemical properties from bulk materials. Therefore, we assessed silver nanoparticle exposure and related health hazards in order to determine whether an additional OEL may be needed. Dosimetric evaluations in our study identified the liver as the most sensitive target organ following inhalation exposure, and as such serves as the critical target organ for setting an occupational exposure standard for airborne silver nanoparticles. This study proposes an OEL of 0.19 μg/m(3) for silver nanoparticles derived from benchmark concentrations (BMCs) from subchronic rat inhalation toxicity assessments and the human equivalent concentration (HEC) with kinetic considerations and additional uncertainty factors. It is anticipated that this level will protect workers from potential health hazards, including lung, liver, and skin damage. PMID:26982810

  15. A dose-controlled system for air-liquid interface cell exposure and application to zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Ferron George A

    2009-12-01

    Full Text Available Abstract Background Engineered nanoparticles are becoming increasingly ubiquitous and their toxicological effects on human health, as well as on the ecosystem, have become a concern. Since initial contact with nanoparticles occurs at the epithelium in the lungs (or skin, or eyes, in vitro cell studies with nanoparticles require dose-controlled systems for delivery of nanoparticles to epithelial cells cultured at the air-liquid interface. Results A novel air-liquid interface cell exposure system (ALICE for nanoparticles in liquids is presented and validated. The ALICE generates a dense cloud of droplets with a vibrating membrane nebulizer and utilizes combined cloud settling and single particle sedimentation for fast (~10 min; entire exposure, repeatable (2. The cell-specific deposition efficiency is currently limited to 0.072 (7.2% for two commercially available 6-er transwell plates, but a deposition efficiency of up to 0.57 (57% is possible for better cell coverage of the exposure chamber. Dose-response measurements with ZnO nanoparticles (0.3-8.5 μg/cm2 showed significant differences in mRNA expression of pro-inflammatory (IL-8 and oxidative stress (HO-1 markers when comparing submerged and air-liquid interface exposures. Both exposure methods showed no cellular response below 1 μg/cm2 ZnO, which indicates that ZnO nanoparticles are not toxic at occupationally allowed exposure levels. Conclusion The ALICE is a useful tool for dose-controlled nanoparticle (or solute exposure of cells at the air-liquid interface. Significant differences between cellular response after ZnO nanoparticle exposure under submerged and air-liquid interface conditions suggest that pharmaceutical and toxicological studies with inhaled (nano-particles should be performed under the more realistic air-liquid interface, rather than submerged cell conditions.

  16. Computational investigation of the mechanical and tribological responses of amorphous carbon nanoparticles

    Science.gov (United States)

    Bucholz, Eric W.; Sinnott, Susan B.

    2013-02-01

    Nanoparticles are a class of materials that have seen increasing use as friction and wear reducers in tribological applications. Amorphous carbon (a-C) films have been the subject of significant scientific and industrial interest for use as solid-state lubricants. Here, we present classical molecular dynamics simulations to investigate the mechanical and tribological responses of a-C nanoparticles that are subjected to external forces between hydrogen-terminated diamond surfaces. Over the range of a-C nanoparticle diameters (2-5 nm) and hydrogenation (0%-50%) considered, the simulations predict a consistent mechanical response where each nanoparticle is highly elastic. The simulations predict that the transition from elastic to plastic response is directly related to an increase in the percentage of carbon-carbon crosslinking within the individual nanoparticles. Contrarily, the simulations also predict that the tribological response is noticeably impacted by changes in diameter and hydrogenation. This is because during friction, hydrogen passivates the unsaturated carbon atoms near the nanoparticle's surface, which prevents interfacial bond formation and allows the nanoparticle to roll within the interface. From these findings, it is demonstrated that a-C nanoparticles are able to provide good tribological performance only when sufficient chemical passivation of the nanoparticles is maintained.

  17. Environmental exposure assessment framework for nanoparticles in solid waste

    DEFF Research Database (Denmark)

    Boldrin, Alessio; Hansen, Steffen Foss; Baun, Anders;

    2014-01-01

    Information related to the potential environmental exposure of engineered nanomaterials (ENMs) in the solid waste management phase is extremely scarce. In this paper, we define nanowaste as separately collected or collectable waste materials which are or contain ENMs, and we present a five...... transformation during waste treatment processes, (2) mechanisms for the release of ENMs, (3) the quantification of nanowaste amounts at the regional scale, (4) a definition of acceptable limit values for exposure to ENMs from nanowaste and (5) the reporting of nanowaste generation data....

  18. Exposure assessment and risk management of engineered nanoparticles: Investigation in semiconductor wafer processing

    Science.gov (United States)

    Shepard, Michele N.

    Engineered nanomaterials (ENMs) are currently used in hundreds of commercial products and industrial processes, with more applications being investigated. Nanomaterials have unique properties that differ from bulk materials. While these properties may enable technological advancements, the potential risks of ENMs to people and the environment are not yet fully understood. Certain low solubility nanoparticles are more toxic than their bulk material, such that existing occupational exposure limits may not be sufficiently protective for workers. Risk assessments are currently challenging due to gaps in data on the numerous emerging materials and applications as well as method uncertainties and limitations. Chemical mechanical planarization (CMP) processes with engineered nanoparticle abrasives are used for research and commercial manufacturing applications in the semiconductor and related industries. Despite growing use, no published studies addressed occupational exposures to nanoparticles associated with CMP or risk assessment and management practices for these scenarios. Additional studies are needed to evaluate potential sources of workplace exposure or emission, as well as to help test and refine assessment methods. This research was conducted to: identify the lifecycle stages and potential exposure sources for ENMs in CMP processes; characterize worker exposure; determine recommended engineering controls and compare risk assessment models. The study included workplace air and surface sampling and an evaluation of qualitative risk banding approaches. Exposure assessment results indicated the potential for worker contact with ENMs on workplace surfaces but did not identify nanoparticles readily dispersed in air during work tasks. Some increases in respirable particle concentrations were identified, but not consistently. Measured aerosol concentrations by number and mass were well below current reference values for poorly soluble low toxicity nanoparticles. From

  19. Presence of Amorphous Carbon Nanoparticles in Food Caramels

    Science.gov (United States)

    Palashuddin, Sk; Jaiswal, Amit; Paul, Anumita; Ghosh, Siddhartha Sankar; Chattopadhyay, Arun

    2012-04-01

    We report the finding of the presence of carbon nanoparticles (CNPs) in different carbohydrate based food caramels, viz. bread, jaggery, sugar caramel, corn flakes and biscuits, where the preparation involves heating of the starting material. The CNPs were amorphous in nature; the particles were spherical having sizes in the range of 4-30 nm, depending upon the source of extraction. The results also indicated that particles formed at higher temperature were smaller than those formed at lower temperature. Excitation tuneable photoluminescence was observed for all the samples with quantum yield (QY) 1.2, 0.55 and 0.63%, for CNPs from bread, jaggery and sugar caramels respectively. The present discovery suggests potential usefulness of CNPs for various biological applications, as the sources of extraction are regular food items, some of which have been consumed by humans for centuries, and thus they can be considered as safe.

  20. Facile Instep Synthesis of Palladium Nanoparticle/Carbon@Carbon Nanotube Composites for Electrooxidation of Xylitol.

    Science.gov (United States)

    Kannan, Ramanujam; Kim, Ae Rhan; Nahm, Kee Suk; Yoo, Dong Jin

    2016-03-01

    The development of a facile, instep, and eco-friendly synthesis method of mono-dispersed low quantity palladium nanoparticle/carbon@functionllized carbon nanotube composite (Pd@C-f-CNT)electrocatalytic material was developed for use in the electrooxidation of xylitol. The prepared nanocatalyst was analyzed by powder X-ray diffraction analysis, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy. The electrocatalytic studies were performed using voltammetric methods. Formation of Pd NPs was observed within 2 min. The microscopic analysis showed 5- to 10-nm-sized Pd NPs that uniformly covered the CNT. The instep-formed carbon helped to improve the electrocatalytic activity of the catalyst. Our proposed method provides new insight for the development of highly efficient metal NPs/CNT nanocatalyst for direct alcohol fuel cell applications. PMID:27455674

  1. Photoresponse from noble metal nanoparticles-multi walled carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Scarselli, M.; Camilli, L.; Castrucci, P.; De Crescenzi, M. [Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Matthes, L. [Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Institut fuer Festkoepertheorie und optik, Friedrich Schiller Universitaet, Max-Wien Platz 1, Jena (Germany); Pulci, O. [Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); ETSF, MIFO, and CNR-ISM, Via del Fosso del Cavaliere, Roma (Italy); Gatto, E.; Venanzi, M. [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy)

    2012-12-10

    In this Letter, we investigated the photo-response of multi wall carbon nanotube-based composites obtained from in situ thermal evaporation of noble metals (Au, Ag, and Cu) on the nanotube films. The metal deposition process produced discrete nanoparticles on the nanotube outer walls. The nanoparticle-carbon nanotube films were characterized by photo-electrochemical measurements in a standard three electrode cell. The photocurrent from the decorated carbon nanotubes remarkably increased with respect to that of bare multiwall tubes. With the aid of first-principle calculations, these results are discussed in terms of metal nanoparticle-nanotube interactions and electronic charge transfer at the interface.

  2. Au nanoparticles and graphene quantum dots co-modified glassy carbon electrode for catechol sensing

    Science.gov (United States)

    Zhao, Xuan; He, Dawei; Wang, Yongsheng; Hu, Yin; Fu, Chen

    2016-03-01

    In this letter, the gold nanoparticles and graphene quantum dots were applied to the modification of glassy carbon electrode for the detection of catechol. The synergist cooperation between gold nanoparticles and graphene quantum dots can increase specific surface area and enhance electronic and catalytic properties of glassy carbon electrode. The detection limit of catechol is 0.869 μmol/L, demonstrating the superior detection efficiency of the gold nanoparticles and graphene quantum dots co-modified glassy carbon electrode as a new sensing platform.

  3. Exposure to TiO2 nanoparticles increases Staphylococcusaureusinfection of HeLa cells

    Science.gov (United States)

    Xu, Yan; Wei, Ming-Tzo; Walker, Stephen. G.; Wang, Hong Zhan; Gondon, Chris; Brink, Peter; Guterman, Shoshana; Zawacki, Emma; Applebaum, Eliana; Rafailovich, Miriam; Ou-Yang, H. Daniel; Mironava, Tatsiana

    TiO2 is one of the most common nanoparticles in industry from food additives to energy generation. Even though TiO2 is also used as an anti-bacterial agent in combination with UV, we found that, in the absence of UV, exposure of HeLa cells to TiO2 nanoparticles largely increased their risk of bacterial invasion. HeLa cells cultured with low dosage rutile and anatase TiO2 nanoparticles (0.1 mg/ml) for 24 hrs prior to exposure to bacteria had 350% and 250% respectively more bacteria infected per cell. The increase was attributed to increased LDH leakage, and changes in the mechanical response of the cell membrane. On the other hand, macrophages exposed to TiO2 particles ingested 40% fewer bacteria, further increasing the risk of infection. In combination, these two factors raise serious concerns regarding the impact of exposure to TiO2 nanoparticles on the ability of organisms to resist bacterial infection.

  4. Catalytic pyrogenation synthesis of C/Ni composite nanoparticles: controllable carbon structures and high permittivities

    Energy Technology Data Exchange (ETDEWEB)

    Lu, B; Huang, H; Dong, X L; Lei, J P, E-mail: dongxl@dlut.edu.c [School of Materials Science and Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China)

    2010-03-17

    Catalytic pyrogenation of methane gas in the presence of Ni nanoparticles was employed to synthesize C/Ni composite nanoparticles at various reaction temperatures. The Ni nanoparticles prepared by the arc-discharge method served as a catalyst to decompose the hydrocarbon molecules and also provided isolated templates for the formation of carbon nanocapsules at 400 and 500 {sup 0}C or multi-walled carbon nanotubes at 600 and 650 {sup 0}C. The generation and growth mechanism of the carbon shells are discussed on the basis of structure evolution. By dispersing the nanoparticles homogeneously into a paraffin matrix, the electromagnetic parameters of the nanoparticles have been investigated in the frequency range 2-18 GHz. The samples exhibit high permittivities varying with the microstructures of the nanoparticles. The relationship between the dielectric properties and diverse carbon structures is indicated. The high permittivities of the nanoparticles are attributed to the better conductivity of the carbon shells and the charge polarizations at the defects or interfaces between metal cores and carbon shells.

  5. Comparative analysis of the secondary electron yield from carbon nanoparticles and pure water medium

    CERN Document Server

    Verkhovtsev, Alexey; de Vera, Pablo; Surdutovich, Eugene; Guatelli, Susanna; Korol, Andrei V; Rosenfeld, Anatoly; Solov'yov, Andrey V

    2015-01-01

    The production of secondary electrons generated by carbon nanoparticles and pure water medium irradiated by fast protons is studied by means of model approaches and Monte Carlo simulations. It is demonstrated that due to a prominent collective response to an external field, the nanoparticles embedded in the medium enhance the yield of low-energy electrons. The maximal enhancement is observed for electrons in the energy range where plasmons, which are excited in the nanoparticles, play the dominant role. Electron yield from a solid carbon nanoparticle composed of fullerite, a crystalline form of C60 fullerene, is demonstrated to be several times higher than that from liquid water. Decay of plasmon excitations in carbon-based nanosystems thus represents a mechanism of increase of the low-energy electron yield, similar to the case of sensitizing metal nanoparticles. This observation gives a hint for investigation of novel types of sensitizers to be composed of metallic and organic parts.

  6. Enhancement of Mechanical and Thermal Properties of Polycaprolactone/Chitosan Blend by Calcium Carbonate Nanoparticles

    OpenAIRE

    Asma Fatehi; Susan Azizi; Mohamad Zaki Ab. Rahman; Wan Md Zin Wan Yunus; Samira Siyamak; Nor Azowa Ibrahim; Sanaz Abdolmohammadi

    2012-01-01

    This study investigates the effects of calcium carbonate (CaCO3) nanoparticles on the mechanical and thermal properties and surface morphology of polycaprolactone (PCL)/chitosan nanocomposites. The nanocomposites of PCL/chitosan/CaCO3 were prepared using a melt blending technique. Transmission electron microscopy (TEM) results indicate the average size of nanoparticles to be approximately 62 nm. Tensile measurement results show an increase in the tensile modulus with CaCO3 nanoparticle loadin...

  7. Gold Nanoparticles as the Catalyst of Single-Walled Carbon Nanotube Synthesis

    OpenAIRE

    Yoshikazu Homma

    2014-01-01

    Gold nanoparticles have been proven to act as efficient catalysts for chemical reactions, such as oxidation and hydrogen production. In this review we focus on a different aspect of the catalysis of gold nanoparticles; single-walled carbon nanotube (SWCNT) synthesis. This is not a traditional meaning of catalytic reaction, but SWCNTs cannot be synthesized without nanoparticles. Previously, gold was considered as unsuitable metal species as the catalyst of SWCNT synthesis. However, gold nanopa...

  8. Binder-Free and Carbon-Free Nanoparticle Batteries: A Method for Nanoparticle Electrodes without Polymeric Binders or Carbon Black

    KAUST Repository

    Ha, Don-Hyung

    2012-10-10

    In this work, we have developed a new fabrication method for nanoparticle (NP) assemblies for Li-ion battery electrodes that require no additional support or conductive materials such as polymeric binders or carbon black. By eliminating these additives, we are able to improve the battery capacity/weight ratio. The NP film is formed by using electrophoretic deposition (EPD) of colloidally synthesized, monodisperse cobalt NPs that are transformed through the nanoscale Kirkendall effect into hollow Co 3O 4. EPD forms a network of NPs that are mechanically very robust and electrically connected, enabling them to act as the Li-ion battery anode. The morphology change through cycles indicates stable 5-10 nm NPs form after the first lithiation remained throughout the cycling process. This NP-film battery made without binders and conductive additives shows high gravimetric (>830 mAh/g) and volumetric capacities (>2100 mAh/cm 3) even after 50 cycles. Because similar films made from drop-casting do not perform well under equal conditions, EPD is seen as the critical step to create good contacts between the particles and electrodes resulting in this significant improvement in battery electrode assembly. This is a promising system for colloidal nanoparticles and a template for investigating the mechanism of lithiation and delithiation of NPs. © 2012 American Chemical Society.

  9. Carbon-coated SnO2 nanobelts and nanoparticles by single catalytic step

    International Nuclear Information System (INIS)

    Several types of carbon nanostructures (amorphous and graphitic), for the coating of SnO2 nanobelts and nanoparticles were obtained by a single catalytic process, during methane, natural gas, and methanol decomposition using the reactivity of surface-modified SnO2 nanostructure as a nanotemplate. The nanostructured catalyst templates were based on transition metal nanoparticles supported on SnO2 nanobelts previously prepared by a carbothermal reduction process. Carbon-coated SnO2 nanopowders were also successfully synthesized for the fabrication of carbon spheres. The carbon coating process and yield, along with the nature of the nanostructured carbon, are strongly influenced by the chemically modified surface of the SnO2 nanostructure template and the chemical reaction gas composition. The preliminary catalytic activity and gas-sensing properties of these novel materials based on metal nanoparticles and carbon-coated SnO2 were determined.

  10. Carbon nanotubes polymer nanoparticles inks for healthcare textile

    Science.gov (United States)

    Rai, Pratyush; Lee, Jungmin; Mathur, Gyanesh N.; Varadan, Vijay K.

    2012-10-01

    Healthcare textiles are ambient health monitoring systems that can contribute towards medical aid as well as general fitness of the populace. These are textile based products that have sensor systems mounted on them or are electrically functionalized to act as sensors. While embedded sensor chipsets and connection wires have been shown as working prototypes of this concept, there is a need for seamless integration of sensor technologies without hindering the inherent properties of the textile. Screen printing or stamping with electrically conductive inks have been demonstrated as technologies for fabricating electronics on flexible substrates. They are applicable to textile manufacturing as well. Printing technology allows for fabrication of nanocomposite based electronics elements in a bottom-up fashion. This has advantages such as low material consumption, high speed fabrication and low temperature processing. In this research, Multi-Wall Carbon Nanotubes (MWCNTs) and polyaniline nanoparticles (PANP) core shell based nanocomposites were synthesized and formulated into colloidal ink. Printed MWCNTs-PANP traces were electrically characterized and compared with traces made with those made by other composites such as Silver, and Carbon Black. The nanocomposite based inks are compared for proposed applications as sensor systems and conductive tracks on smart textile for pervasive wireless healthcare system that can be mass produced using low cost printing processes.

  11. Luminescence behavior of silicon and carbon nanoparticles dispersed in low-polar liquids

    OpenAIRE

    Ryabchikov, Yury V; Alekseev, Sergei A; Lysenko, Vladimir V; Bremond, Georges; Bluet, Jean-Marie

    2012-01-01

    A comparative photoluminescence analysis of as-prepared and chemically modified (by alkyl chains -C18H37) silicon and carbon nanoparticles dispersed in low-polar liquids is reported. Influence of the low-polar liquid nature and ambient temperature on photoluminescence of the nanoparticles has been investigated from the point of view of their possible application as thermal nanoprobes.

  12. Metallic nanoparticles deposited on carbon microspheres: novel materials for combinatorial electrochemistry and electroanalysis.

    Science.gov (United States)

    Baron, Ronan; Wildgoose, Gregory G; Compton, Richard G

    2009-04-01

    This review deals with the preparation of metallic nanoparticles on glassy carbon microspheres and the use of these new hybrid materials for combinatorial electrochemistry and electroanalysis. First, the preparation of gold, silver and palladium nanoparticles on glassy carbon microspheres by a simple electroless procedure is described. Then, different types of electrodes modified with glassy carbon microspheres are described. These are: (i) glassy carbon electrodes modified by a composite film of glassy carbon microspheres and multi-walled carbon nanotubes, (ii) basal plane pyrolylic graphite electrodes modified by the abrasive attachment of glassy carbon microspheres and (iii) carbon-epoxy composite electrodes loaded with glassy carbon microspheres. The three types of electrode architectures described consist of metallic nanoparticles embedded in a carbon matrix and each of the electrode macrodisc surfaces actually correspond to a random metallic nanoelectrode array. Carbon-epoxy composite electrodes have good characteristics for their use as practical sensors. Furthermore, the use of several kinds of metallic nanoparticles allows the construction of a multi-analyte electrode and the screening of electroactive materials by following a combinatorial approach. PMID:19437964

  13. Characterisation and catalytic properties of Ni, Co, Ce and Ru nanoparticles in mesoporous carbon spheres

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Francisco A. A. [Universidade Federal do Ceara, Departamento de Quimica Analitica e Fisico-Quimica, Langmuir Lab de Adsorcao e Catalise (Brazil); Castro, Antonio J. R.; Filho, Josue M. [Universidade Federal do Ceara, Departamento de Fisica (Brazil); Viana, Bartolomeu C. [Universidade Federal do Piaui, Departamento de Fisica (Brazil); Campos, Adriana [CETENE Av. Prof. Luiz Freire, Cidade Universitaria (Brazil); Oliveira, Alcineia C., E-mail: alcineia@ufc.br [Universidade Federal do Ceara, Departamento de Quimica Analitica e Fisico-Quimica, Langmuir Lab de Adsorcao e Catalise (Brazil)

    2012-09-15

    Ni, Co, Ce and Ru nanoparticles were inserted into templated carbon using a nanocasting technique and evaluated for the dehydration of glycerol. NiO and CeO{sub 2} preferentially yielded 5 nm uniformly sized particles that filled the mesoporous carbon via a geometric confinement effect. Ru generated Ru{sup o} and RuO{sub 2} nanoparticles that selectively migrated towards the carbon surface and did not undergo sintering, whereas Co nanoparticles containing CoO and Co{sub 3}O{sub 4} showed the opposite behaviour. The stabilising effects of the Ce and Ru nanoparticles on the carbon matrix effectively prevented the aggregation of small particles, resulting in superior catalytic performance in glycerol dehydration.

  14. Biopolymer protected silver nanoparticles on the support of carbon nanotube as interface for electrocatalytic applications

    Science.gov (United States)

    Satyanarayana, M.; Kumar, V. Sunil; Gobi, K. Vengatajalabathy

    2016-04-01

    In this research, silver nanoparticles (SNPs) are prepared on the surface of carbon nanotubes via chitosan, a biopolymer linkage. Here chitosan act as stabilizing agent for nanoparticles and forms a network on the surface of carbon nanotubes. Synthesized silver nanoparticles-MWCNT hybrid composite is characterized by UV-Visible spectroscopy, XRD analysis, and FESEM with EDS to evaluate the structural and chemical properties of the nanocomposite. The electrocatalytic activity of the fabricated SNP-MWCNT hybrid modified glassy carbon electrode has been evaluated by cyclic voltammetry and electrochemical impedance analysis. The silver nanoparticles are of size ˜35 nm and are well distributed on the surface of carbon nanotubes with chitosan linkage. The prepared nanocomposite shows efficient electrocatalytic properties with high active surface area and excellent electron transfer behaviour.

  15. Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate

    OpenAIRE

    Mortensen Alicja; Vogel Ulla; Gao Xueyun; Larsen Agnete; Qvortrup Klaus; Hadrup Niels; Loeschner Katrin; Lam Henrik; Larsen Erik H

    2011-01-01

    Abstract Background The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles (AgNPs) and silver acetate (AgAc) to rats. Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food and food contact materials. Results AgNPs were synthesized with a size distribution of 14 ± 4 nm in diameter (90% of the nanoparticle volume) and stabilized in aqueous suspension by the polymer ...

  16. Exposure to titanium dioxide and other metallic oxide nanoparticles induces cytotoxicity on human neural cells and fibroblasts

    Directory of Open Access Journals (Sweden)

    James C K Lai

    2008-12-01

    Full Text Available James C K Lai1, Maria B Lai1, Sirisha Jandhyam1, Vikas V Dukhande1, Alok Bhushan1, Christopher K Daniels1, Solomon W Leung21Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, and Biomedical Research Institute; 2Department of Civil and Environmental Engineering, College of Engineering and Biomedical Research Institute, Idaho State University, Pocatello, ID, USAAbstract: The use of titanium dioxide (TiO2 in various industrial applications (eg, production of paper, plastics, cosmetics, and paints has been expanding thereby increasing the occupational and other environmental exposure of these nanoparticles to humans and other species. However, the health effects of exposure to TiO2 nanoparticles have not been systematically assessed even though recent studies suggest that such exposure induces inflammatory responses in lung tissue and cells. Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts. We found that TiO2 micro- and nanoparticles induced cell death on both human cell types in a concentration-related manner. We further noted that zinc oxide (ZnO nanoparticles were the most effective, TiO2 nanoparticles the second most effective, and magnesium oxide (MgO nanoparticles the least effective in inducing cell death in U87 cells. The cell death mechanisms underlying the effects of TiO2 micro- and nanoparticles on U87 cells include apoptosis, necrosis, and possibly apoptosis-like and necrosis-like cell death types. Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.Keywords: cytotoxicity of titanium dioxide micro- and nanoparticles, cytotoxicity of zinc oxide and magnesium oxide nanoparticles, human neural cells

  17. Assessing Nanoparticle Toxicity

    Science.gov (United States)

    Love, Sara A.; Maurer-Jones, Melissa A.; Thompson, John W.; Lin, Yu-Shen; Haynes, Christy L.

    2012-07-01

    Nanoparticle toxicology, an emergent field, works toward establishing the hazard of nanoparticles, and therefore their potential risk, in light of the increased use and likelihood of exposure. Analytical chemists can provide an essential tool kit for the advancement of this field by exploiting expertise in sample complexity and preparation as well as method and technology development. Herein, we discuss experimental considerations for performing in vitro nanoparticle toxicity studies, with a focus on nanoparticle characterization, relevant model cell systems, and toxicity assay choices. Additionally, we present three case studies (of silver, titanium dioxide, and carbon nanotube toxicity) to highlight the important toxicological considerations of these commonly used nanoparticles.

  18. Three-dimensional heterostructure of metallic nanoparticles and carbon nanotubes as potential nanofiller

    OpenAIRE

    Kim, Whi Dong; Huh, Jun Young; Ahn, Ji Young; Lee, Jae Beom; Lee, Dongyun; Hong, Suck Won; Kim, Soo Hyung

    2012-01-01

    The effect of the dimensionality of metallic nanoparticle-and carbon nanotube-based fillers on the mechanical properties of an acrylonitrile butadiene styrene (ABS) polymer matrix was examined. ABS composite films, reinforced with low dimensional metallic nanoparticles (MNPs, 0-D) and carbon nanotubes (CNTs, 1-D) as nanofillers, were fabricated by a combination of wet phase inversion and hot pressing. The tensile strength and elongation of the ABS composite were increased by 39% and 6%, respe...

  19. Isotopically modified silver nanoparticles to assess nanosilver bioavailability and toxicity at environmentally relevant exposures

    Science.gov (United States)

    Croteau, Marie-Noële; Dybowska, Agnieszka D.; Luoma, Samuel N.; Misra, Superb K.; Valsami-Jones, Eugenia

    2014-01-01

    A major challenge in understanding the environmental implications of nanotechnology lies in studying nanoparticle uptake in organisms at environmentally realistic exposure concentrations. Typically, high exposure concentrations are needed to trigger measurable effects and to detect accumulation above background. But application of tracer techniques can overcome these limitations. Here we synthesised, for the first time, citrate-coated Ag nanoparticles using Ag that was 99.7 % 109Ag. In addition to conducting reactivity and dissolution studies, we assessed the bioavailability and toxicity of these isotopically modified Ag nanoparticles (109Ag NPs) to a freshwater snail under conditions typical of nature. We showed that accumulation of 109Ag from 109Ag NPs is detectable in the tissues of Lymnaea stagnalis after 24-h exposure to aqueous concentrations as low as 6 ng L–1 as well as after 3 h of dietary exposure to concentrations as low as 0.07 μg g–1. Silver uptake from unlabelled Ag NPs would not have been detected under similar exposure conditions. Uptake rates of 109Ag from 109Ag NPs mixed with food or dispersed in water were largely linear over a wide range of concentrations. Particle dissolution was most important at low waterborne concentrations. We estimated that 70 % of the bioaccumulated 109Ag concentration in L. stagnalis at exposures –1 originated from the newly solubilised Ag. Above this concentration, we predicted that 80 % of the bioaccumulated 109Ag concentration originated from the 109Ag NPs. It was not clear if agglomeration had a major influence on uptake rates.

  20. A novel approach reveals that zinc oxide nanoparticles are bioavailable and toxic after dietary exposures.

    Science.gov (United States)

    Croteau, Marie-Noële; Dybowska, Agnieszka D; Luoma, Samuel N; Valsami-Jones, Eugenia

    2011-03-01

    If engineered nanomaterials are released into the environment, some are likely to end up associated with the food of animals due to aggregation and sorption processes. However, few studies have considered dietary exposure of nanomaterials. Here we show that zinc (Zn) from isotopically modified (67)ZnO particles is efficiently assimilated by freshwater snails when ingested with food. The (67)Zn from nano-sized (67)ZnO appears as bioavailable as (67)Zn internalized by diatoms. Apparent agglomeration of the zinc oxide (ZnO) particles did not reduce bioavailability, nor preclude toxicity. In the diet, ZnO nanoparticles damage digestion: snails ate less, defecated less and inefficiently processed the ingested food when exposed to high concentrations of ZnO. It was not clear whether the toxicity was due to the high Zn dose achieved with nanoparticles or to the ZnO nanoparticles themselves. Further study of exposure from nanoparticles in food would greatly benefit assessment of ecological and human health risks. PMID:21417690

  1. Process-generated nanoparticles from ceramic tile sintering: Emissions, exposure and environmental release.

    Science.gov (United States)

    Fonseca, A S; Maragkidou, A; Viana, M; Querol, X; Hämeri, K; de Francisco, I; Estepa, C; Borrell, C; Lennikov, V; de la Fuente, G F

    2016-09-15

    The ceramic industry is an industrial sector in need of significant process changes, which may benefit from innovative technologies such as laser sintering of ceramic tiles. Such innovations result in a considerable research gap within exposure assessment studies for process-generated ultrafine and nanoparticles. This study addresses this issue aiming to characterise particle formation, release mechanisms and their impact on personal exposure during a tile sintering activity in an industrial-scale pilot plant, as a follow-up of a previous study in a laboratory-scale plant. In addition, possible particle transformations in the exhaust system, the potential for particle release to the outdoor environment, and the effectiveness of the filtration system were also assessed. For this purpose, a tiered measurement strategy was conducted. The main findings evidence that nanoparticle emission patterns were strongly linked to temperature and tile chemical composition, and mainly independent of the laser treatment. Also, new particle formation (from gaseous precursors) events were detected, with nanoparticles reference value (NRV; 4×10(4)cm(-3)), with 8-hour time weighted average concentrations in the range of 1.4×10(5)cm(-3) and 5.3×10(5)cm(-3). A potential risk for nanoparticle and ultrafine particle release to the environment was also identified, despite the fact that the efficiency of the filtration system was successfully tested and evidenced a >87% efficiency in particle number concentrations removal. PMID:26848012

  2. A novel approach reveals that zinc oxide nanoparticles are bioavailable and toxic after dietary exposures

    Science.gov (United States)

    Croteau, M.-N.; Dybowska, A.D.; Luoma, S.N.; Valsami-Jones, E.

    2011-01-01

    If engineered nanomaterials are released into the environment, some are likely to end up associated with the food of animals due to aggregation and sorption processes. However, few studies have considered dietary exposure of nanomaterials. Here we show that zinc (Zn) from isotopically modified 67ZnO particles is efficiently assimilated by freshwater snails when ingested with food. The 67Zn from nano-sized 67ZnO appears as bioavailable as 67Zn internalized by diatoms. Apparent agglomeration of the zinc oxide (ZnO) particles did not reduce bioavailability, nor preclude toxicity. In the diet, ZnO nanoparticles damage digestion: snails ate less, defecated less and inefficiently processed the ingested food when exposed to high concentrations of ZnO. It was not clear whether the toxicity was due to the high Zn dose achieved with nanoparticles or to the ZnO nanoparticles themselves. Further study of exposure from nanoparticles in food would greatly benefit assessment of ecological and human health risks. ?? 2011 Informa UK, Ltd.

  3. Effects of prenatal inhalation exposure to copper nanoparticles on murine dams and offspring

    OpenAIRE

    Adamcakova-Dodd, Andrea; Monick, Martha M.; Powers, Linda S.; Gibson-Corley, Katherine N.; Thorne, Peter S.

    2015-01-01

    Background Increasing numbers of individuals may be exposed to nanomaterials during pregnancy. The overarching goal of this investigation was to determine if prenatal inhalation exposure to copper nanoparticles (Cu NPs) has an effect on dams and offspring, including an analysis of inflammatory markers (Th1/Th2 cytokine profiles). Methods Physicochemical characterization of Cu NPs was performed. Pregnant and non-pregnant mice (C57Bl/6 J) were exposed to Cu NPs or laboratory air in the whole-bo...

  4. Impacts of Hematite Nanoparticle Exposure on Biomechanical, Adhesive, and Surface Electrical Properties of Escherichia coli Cells

    OpenAIRE

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-01-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomater...

  5. Workplace exposure to nanoparticles and the application of provisional nanoreference values in times of uncertain risks

    International Nuclear Information System (INIS)

    Nano reference values (NRVs) for occupational use of nanomaterials were tested as provisional substitute for Occupational Exposure Limits (OELs). NRVs can be used as provisional limit values until Health-Based OELs or derived no-effect levels (DNEL) become available. NRVs were defined for 8 h periods (time weighted average) and for short-term exposure periods (15 min-time weighted average). To assess the usefulness of these NRVs, airborne number concentrations of nanoparticles (NPs) in the workplace environment were measured during paint manufacturing, electroplating, light equipment manufacturing, non-reflective glass production, production of pigment concentrates and car refinishing. Activities monitored were handling of solid engineered NPs (ENP), abrasion, spraying and heating during occupational use of nanomaterials (containing ENPs) and machining nanosurfaces. The measured concentrations are often presumed to contain ENPs as well as process-generated NPs (PGNP). The PGNP are found to be a significant source for potential exposure and cannot be ignored in risk assessment. Levels of NPs identified in workplace air were up to several millions of nanoparticles/cm3. Conventional components in paint manufacturing like CaCO3 and talc may contain a substantial amount of nanosized particulates giving rise to airborne nanoparticle concentrations. It is argued that risk assessments carried out for e.g. paint manufacturing processes using conventional non-nano components should take into account potential nanoparticle emissions as well. The concentrations measured were compared with particle-based NRVs and with mass-based values that have also been proposed for workers protection. It is concluded that NRVs can be used for risk management for handling or processing of nanomaterials at workplaces provided that the scope of NRVs is not limited to ENPs only, but extended to the exposure to process-generated NPs as well.

  6. Regulation of Plasminogen Activator Inhibitor-1 Expression in Endothelial Cells with Exposure to Metal Nanoparticles

    OpenAIRE

    Yu, Min; Mo, Yiqun; Wan, Rong; Chien, Sufan; Zhang, Xing; Zhang, Qunwei

    2010-01-01

    Recent studies demonstrated that exposure to nanoparticles could enhance the adhesion of endothelial cells and modify the membrane structure of vascular endothelium. The endothelium plays an important role in the regulation of fibrinolysis, and imbalance of the fibrinolysis system potential contributes to the development of thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is the most potent endogenous inhibitor of fibrinolysis and is involved in the pathogenesis of several cardiovascular...

  7. Organ weight changes in mice after long-term inhalation exposure to manganese oxides nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Zeman, T.; Buchtová, Marcela; Dočekal, Bohumil; Míšek, Ivan; Mikuška, P.; Šerý, Omar

    2014. O4a-3. [International conference on safe production and use of nanomaterials /4./. 18.11.2014-20.11.2014, Grenoble] R&D Projects: GA ČR(CZ) GAP503/11/2315; GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:68081715 ; RVO:67985904 Keywords : long-term inhalation exposure * manganese oxides nanoparticles * mice Subject RIV: CB - Analytical Chemistry, Separation

  8. Surface area as a dose metric for carbon black nanoparticles: A study of oxidative stress, DNA single-strand breakage and inflammation in rats

    Science.gov (United States)

    Chuang, Hsiao-Chi; Chen, Li-Chen; Lei, Yu-Chen; Wu, Kuen-Yuh; Feng, Po-Hao; Cheng, Tsun-Jen

    2015-04-01

    Combustion-derived nanoparticles are characterised by a high surface area (SA) per mass. SA is proposed to regulate the bioreactivity of nanoparticles; however, the dose metric for carbon black remains controversial. To determine the relationships between bioreactivity and SA, male spontaneously hypertensive rats were exposed to carbon black (CB) nanoparticles (15, 51 and 95 nm) via intratracheal instillation for 24 h. Pulmonary exposure to CB resulted in a significant increase in systemic 8-hydroxy-2‧-deoxyguanosine (8-OHdG), DNA single-strand breakages in peripheral blood cells and pulmonary cell infiltration in rats. The oxidative potential and particularly the corresponding SA of CB were correlated with the level of 8-OHdG, DNA single-strand breakages and pulmonary cell infiltration in rats. We conclude that SA is an important dose metric for CB that can regulate oxidative stress and DNA damage in rats. Furthermore, this observation was more significant for smaller sized CB.

  9. Effects of exposure to nanoparticle-rich diesel exhaust on 8-OHdG synthesis in the mouse asthmatic lung

    OpenAIRE

    TANAKA, MICHITAKA; Takano, Hirohisa; Fujitani, Yuji; Hirano, Seishiro; Ichinose, Takamichi; SHIMADA, Akinori; Inoue, Ken-ichiro

    2013-01-01

    It has been demonstrated that exposure to diesel exhaust (DE) is associated with the induction and exacerbation of respiratory disorders; however, the impacts of DE containing mainly nanoparticles have been less studied. We have previously demonstrated that inhalation exposure to nanoparticle-rich DE (NR-DE) exacerbated allergic pulmonary inflammation, in the context of enhanced local expression of proinflammatory molecules. However, the underlying mechanisms have not been fully elucidated. 8...

  10. Cytotoxicity of TiO{sub 2} nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Jyoti; Kumar, Deepak; Mathur, Ankita; Naseer, Arif; Kumar, Ravi Ranjan [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Thanjavur Chandrasekaran, Prathna [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Chaudhuri, Gouri; Pulimi, Mrudula [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Raichur, Ashok M. [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Department of Chemical Technology, University of Johannesburg (South Africa); Babu, S. [School of Bio Sciences and Technology, VIT University, Vellore (India); Chandrasekaran, Natarajan [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Nagarajan, R. [Department of Chemical Engineering, IIT Madras, Chennai (India); Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India)

    2014-11-15

    There is a persistent need to assess the effects of TiO{sub 2} nanoparticles on the aquatic ecosystem owing to their increasing usage in consumer products and risk of environmental release. The current study is focused on TiO{sub 2} nanoparticle-induced acute toxicity at sub-ppm level (≤1 ppm) on the three different freshwater sediment bacterial isolates and their consortium under two different irradiation (visible light and dark) conditions. The consortium of the bacterial isolates was found to be less affected by the exposure to the nanoparticles compared to the individual cells. The oxidative stress contributed considerably towards the cytotoxicity under both light and dark conditions. A statistically significant increase in membrane permeability was noted under the dark conditions as compared to the light conditions. The optical and fluorescence microscopic images showed aggregation and chain formation of the bacterial cells, when exposed to the nanoparticles. The electron microscopic (SEM, TEM) observations suggested considerable damage of cells and bio-uptake of nanoparticles. The exopolysaccrides (EPS) production and biofilm formation were noted to increase in the presence of the nanoparticles, and expression of the key genes involved in biofilm formation was studied by RT-PCR. - Highlights: • Toxicity of NPs towards freshwater sediment bacteria at sub-ppm concentrations. • Decreased toxicity of the nanoparticles in the consortium of microorganisms. • Enhanced bacterial resistance through EPS and biofilm formation in the presence of NPs. • Considerable surface damage of cells and internalization of NPs. • Gene expression analyses related to biofilm formation in the presence of NPs.

  11. Cytotoxicity of TiO2 nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

    International Nuclear Information System (INIS)

    There is a persistent need to assess the effects of TiO2 nanoparticles on the aquatic ecosystem owing to their increasing usage in consumer products and risk of environmental release. The current study is focused on TiO2 nanoparticle-induced acute toxicity at sub-ppm level (≤1 ppm) on the three different freshwater sediment bacterial isolates and their consortium under two different irradiation (visible light and dark) conditions. The consortium of the bacterial isolates was found to be less affected by the exposure to the nanoparticles compared to the individual cells. The oxidative stress contributed considerably towards the cytotoxicity under both light and dark conditions. A statistically significant increase in membrane permeability was noted under the dark conditions as compared to the light conditions. The optical and fluorescence microscopic images showed aggregation and chain formation of the bacterial cells, when exposed to the nanoparticles. The electron microscopic (SEM, TEM) observations suggested considerable damage of cells and bio-uptake of nanoparticles. The exopolysaccrides (EPS) production and biofilm formation were noted to increase in the presence of the nanoparticles, and expression of the key genes involved in biofilm formation was studied by RT-PCR. - Highlights: • Toxicity of NPs towards freshwater sediment bacteria at sub-ppm concentrations. • Decreased toxicity of the nanoparticles in the consortium of microorganisms. • Enhanced bacterial resistance through EPS and biofilm formation in the presence of NPs. • Considerable surface damage of cells and internalization of NPs. • Gene expression analyses related to biofilm formation in the presence of NPs

  12. Surface modified carbon nanoparticle papers and applications on polymer composites

    Science.gov (United States)

    Ouyang, Xilian

    Free-standing paper like materials are usually employed as protective layers, chemical filters, components of electrical batteries or supercapacitors, adhesive layers, and electronic or optoelectric components. Free-standing papers made from carbon nanoparticles have drawn increased interest because they have a variety of superior chemical and physical characteristics, such as light weight, high intrinsic mechanical properties, and extraordinary high electrical conductivity. Nanopapers fabricated from 1- D shape carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are promising reinforcing materials for polymer composites, because the highly porous CNF and CNT nanopapers (porosity ˜80% and ˜70% respectively) can be impregnated with matrix polymers. In the first part of this work, polyaniline (PANI) was used to functionalize the surface of CNFs, and the resultant carbon nanopapers presented impressive mechanical strength and electrical conductivity that it could be used in the in-mold coating (IMC)/ injection molding process to achieve high electromagnetic interference (EMI) shielding effectiveness. Aniline modified (AF) CNT nanopapers were used as a 3D network in gas separation membranes. The resultant composite membranes demonstrated better and stable CO2 permeance and CO 2/H2 selectivity in a high temperature (107°C) and high pressure (15-30 atm) gas separation process, not achievable by conventional polymer membranes. In the second part, we demonstrated that 2-D graphene (GP) or graphene oxide (GO) nanosheets could be tightly packed into a film which was impermeable to most gases and liquids. GP or GO nanopapers could be coated on polymer composites. In order to achieve well-dispersed single-layer graphene in aqueous medium, we developed a facile approach to synthesize functional GP bearing benzenesulfonic acid groups which allow the preparation of nanopapers by water based assembly. With the optimized processing conditions, our best GP nanopapers could reach

  13. Lung inflammation and genotoxicity following pulmonary exposure to nanoparticles in ApoE-/- mice

    Directory of Open Access Journals (Sweden)

    Ladefoged Ole

    2009-01-01

    Full Text Available Abstract Background The toxic and inflammatory potential of 5 different types of nanoparticles were studied in a sensitive model for pulmonary effects in apolipoprotein E knockout mice (ApoE-/-. We studied the effects instillation or inhalation Printex 90 of carbon black (CB and compared CB instillation in ApoE-/- and C57 mice. Three and 24 h after pulmonary exposure, inflammation was assessed by mRNA levels of cytokines in lung tissue, cell composition, genotoxicity, protein and lactate dehydrogenase activity in broncho-alveolar lavage (BAL fluid. Results Firstly, we found that intratracheal instillation of CB caused far more pulmonary toxicity in ApoE-/- mice than in C57 mice. Secondly, we showed that instillation of CB was more toxic than inhalation of a presumed similar dose with respect to inflammation in the lungs of ApoE-/- mice. Thirdly, we compared effects of instillation in ApoE-/- mice of three carbonaceous particles; CB, fullerenes C60 (C60 and single walled carbon nanotubes (SWCNT as well as gold particles and quantum dots (QDs. Characterization of the instillation media revealed that all particles were delivered as agglomerates and aggregates. Significant increases in Il-6, Mip-2 and Mcp-1 mRNA were detected in lung tissue, 3 h and 24 h following instillation of SWCNT, CB and QDs. DNA damage in BAL cells, the fraction of neutrophils in BAL cells and protein in BAL fluid increased statistically significantly. Gold and C60 particles caused much weaker inflammatory responses. Conclusion Our data suggest that ApoE-/- model is sensitive for evaluating particle induced inflammation. Overall QDs had greatest effects followed by CB and SWCNT with C60 and gold being least inflammatory and DNA-damaging. However the gold was used at a much lower mass dose than the other particles. The strong effects of QDs were likely due to Cd release. The surface area of the instilled dose correlated well the inflammatory response for low toxicity particles.

  14. Supercritical CO 2 -philic nanoparticles suitable for determining the viability of carbon sequestration in shale

    KAUST Repository

    Xu, Yisheng

    2015-01-01

    © The Royal Society of Chemistry. A fracture spacing less than a decimeter is probably required for the successful sequestration of CO2 in shale. Tracer experiments using inert nanoparticles could determine if a fracturing this intense has been achieved. Here we describe the synthesis of supercritical CO2-philic nanoparticles suitable for this application. The nanoparticles are ~50 nm in diameter and consist of iron oxide (Fe3O4) and silica (SiO2) cores functionalized with a fluorescent polymeric corona. The nanoparticles stably disperse in supercritical carbon dioxide (scCO2) and are detectable to concentrations of 10 ppm. This journal is

  15. Gold Nanoparticles as the Catalyst of Single-Walled Carbon Nanotube Synthesis

    Directory of Open Access Journals (Sweden)

    Yoshikazu Homma

    2014-03-01

    Full Text Available Gold nanoparticles have been proven to act as efficient catalysts for chemical reactions, such as oxidation and hydrogen production. In this review we focus on a different aspect of the catalysis of gold nanoparticles; single-walled carbon nanotube (SWCNT synthesis. This is not a traditional meaning of catalytic reaction, but SWCNTs cannot be synthesized without nanoparticles. Previously, gold was considered as unsuitable metal species as the catalyst of SWCNT synthesis. However, gold nanoparticles with diameters smaller than 5 nm were found to effectively produce SWCNTs. We discuss the catalysis of gold and related metals for SWCNT synthesis in comparison with conventional catalysts, such as iron, cobalt, and nickel.

  16. Size-controllable fabrication of Cu nanoparticles on carbon nanotubes by simple heating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chun; Wu, Shujing; Zheng, He; Cao, Fan; Sheng, Huaping; Zhao, Dongshan; Wang, Jianbo

    2015-01-15

    Highlights: • Cu nanoparticles were synthesized on the surface of carbon nanotubes by heating. • The particle size could be tuned by controlling the temperature and duration. • The possible nucleation and growth mechanisms of nanoparticles were discussed. - Abstract: In this paper, employing simple heating inside the transmission electron microscope, we demonstrated the decoration of carbon nanotubes (CNTs) by Cu nanoparticles (NPs). More significantly, the particle sizes could be effectively controlled by simply controlling the temperature and duration. It is believed that the nucleation and growth of NPs results from the deposition of generated Cu vapor as well as the surface diffusion of Cu on the CNTs at elevated temperature.

  17. Size-controllable fabrication of Cu nanoparticles on carbon nanotubes by simple heating

    International Nuclear Information System (INIS)

    Highlights: • Cu nanoparticles were synthesized on the surface of carbon nanotubes by heating. • The particle size could be tuned by controlling the temperature and duration. • The possible nucleation and growth mechanisms of nanoparticles were discussed. - Abstract: In this paper, employing simple heating inside the transmission electron microscope, we demonstrated the decoration of carbon nanotubes (CNTs) by Cu nanoparticles (NPs). More significantly, the particle sizes could be effectively controlled by simply controlling the temperature and duration. It is believed that the nucleation and growth of NPs results from the deposition of generated Cu vapor as well as the surface diffusion of Cu on the CNTs at elevated temperature

  18. Preparation and characterization of aligned carbon nanotubes coated with titania nanoparticles

    Institute of Scientific and Technical Information of China (English)

    YU Hongtao; ZHAO Huimin; QUAN Xie; CHEN Shuo

    2006-01-01

    Well-aligned carbon nanotubes coated with titania (TiO2) were prepared by atmospheric pressure chemical vapor deposition (APCVD), and the sequential experiments including carbon nanotubes preparation, air-oxidation purification and titania nanoparticles coating were performed at different temperatures in the same reactor. Scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction patterns (XRD), and energy- dispersive X-ray spectra (EDX) demonstrated the well-aligned nanotubes and TiO2 nanoparticles in close proximity and the average diameter of TiO2 nanoparticles was 11.5 nm.

  19. One-step synthesis of fluorescent carbon nanoparticles for degradation of naphthol green under visible light

    International Nuclear Information System (INIS)

    A novel solvothermal approach to synthesize fluorescent carbon nanoparticles (CNPs) was developed by using citric acid and ammonium oxalateas as the carbon source, glycol as the solvent. The solution of the as-prepared CNPs emitted strong blue fluorescence under UV 365 nm, and the particles were well- dispersed with an average diameter of about 30–40 nm. The solution of the obtained CNPs was applied to photocatalytic degradation of naphthol green, and the decolorization rate is over 91% when the reaction time reaches more than 5 h under visible light in the presence of hydrogen peroxide. - Highlights: • A one-step synthesis of carbon nanoparticles method was developed. • The citric acid and ammoniumoxalate were used as carbon source for the first time. • The photocatalytic activity of carbon nanoparticles under visible light was evaluated

  20. Nanoparticle Filtration in a RTM Processed Epoxy/Carbon Fiber Composite

    Science.gov (United States)

    Miller, Sandi G.; Micham, Logan; Copa, Christine C.; Criss, James M., Jr.; Mintz, Eric A.

    2011-01-01

    Several epoxy matrix composite panels were fabricated by resin transfer molding (RTM) E862/W resin onto a triaxially braided carbon fiber pre-form. Nanoparticles including carbon nanofiber, synthetic clay, and functionalized graphite were dispersed in the E862 matrix, and the extent of particle filtration during processing was characterized. Nanoparticle dispersion in the resin flashing on both the inlet and outlet edges of the panel was compared by TEM. Variation in physical properties such as Tg and moisture absorption throughout the panel were also characterized. All nanoparticle filled panels showed a decrease in Tg along the resin flow path across the panel, indicating nanoparticle filtration, however there was little change in moisture absorption. This works illustrates the need to obtain good nano-particle dispersion in the matrix resin to prevent particle agglomeration and hence particle filtration in the resultant polymer matrix composites (PMC).

  1. Electric Characteristics of the Carbon Nanotube Network Transistor with Directly Grown ZnO Nanoparticles.

    Science.gov (United States)

    Kim, Un Jeong; Bae, Gi Yoon; Suh, Dong Ik; Park, Wanjun

    2016-03-01

    We report on the electrical characteristics of field effect transistors fabricated with random networks of single-walled carbon nanotubes with surfaces modified by ZnO nanoparticles. ZnO nanoparticles are directly grown on single-walled carbon nanotubes by atomic layer deposition using diethylzinc (DEZ) and water. Electrical observations show that ZnO nanoparticles act as charge transfer sources that provide electrons to the nanotube channel. The valley position in ambipolar transport of nanotube transistors is negatively shifted for 3V due to the electronic n-typed property of ZnO nanoparticles. However, the Raman resonance remains invariant despite the charge transfer effect produced by ZnO nanoparticles. PMID:27455727

  2. Understanding the mechanism of toxicity of carbon nanoparticles in humans in the new millennium: A systemic review

    Directory of Open Access Journals (Sweden)

    Sharma Mukesh

    2010-01-01

    Full Text Available Manmade nanoparticles range from the well-established multi-ton production of carbon black and fumed silica for applications in plastic fillers and car tyres to microgram quantities of fluorescent quantum dots used as markers in biological imaging. While benefits of nanotechnology are widely publicized, the discussion of the potential effects of their widespread use in the consumer and industrial products are just beginning to emerge. Acceptance of nanoparticle toxicity led to wide acceptance of the fact that nanotoxicology, as a scientific discipline shall be quite different from occupational hygiene in approach and context. Understanding the toxicity of nanomaterials and nano-enabled products is important for human and environmental health and safety as well as public acceptance. Assessing the state of knowledge about nanotoxicology is an important step in promoting comprehensive understanding of the health and environmental implications of these new materials. Very limited data exist for health effects secondary to inhalation of very fine respirable particles in the occupational environment. Nanomaterials may have effects on health due to their size, surface, shape, charge, or other factors, which are not directly predictable from mass concentration measurements. Numerous epidemiological studies have associated exposure to small particles such as combustion-generated fine particles with lung cancer, heart disease, asthma and/or increased mortality. The omnipresence of nanoparticles shifts focus of research toward efforts to mitigate the health effects of nanoparticles. Newer health assessment methods and newer techniques need to be developed for diagnosing sub-optimal health in populations exposed to carbon nanoparticles.

  3. High ordered biomineralization induced by carbon nanoparticles in the sea urchin Paracentrotus lividus

    International Nuclear Information System (INIS)

    A surprising and unexpected biomineralization process was observed during toxicological assessment of carbon nanoparticles on Paracentrotus lividus (sea urchin) pluteus larvae. The larvae activate a process of defense against external material, by incorporating the nanoparticles into microstructures of aragonite similarly to pearl oysters. Aiming at a better understanding of this phenomenon, the larvae were exposed to increasing concentrations of carbon nanoparticles and the biomineralization products were analyzed by electron microscopy, x-ray diffraction and Raman spectroscopy. In order to evaluate the possible influence of Sp-CyP-1 expression on this biomineralization process by larvae, analyses of gene expression (Sp-CyP-1) and calcein labeling were performed. Overall, we report experimental evidence about the capability of carbon nanoparticles to induce an increment of Sp-CyP-1 expression with the consequent activation of a biomineralization process leading to the production of a new pearl-like biomaterial never previously observed in sea urchins. (paper)

  4. Multiple-diffusion flame synthesis of pure anatase and carbon-coated titanium dioxide nanoparticles

    KAUST Repository

    Memon, Nasir

    2013-09-01

    A multi-element diffusion flame burner (MEDB) is useful in the study of flame synthesis of nanomaterials. Here, the growth of pure anatase and carbon-coated titanium dioxide (TiO2) using an MEDB is demonstrated. Hydrogen (H2), oxygen (O2), and argon (Ar) are utilized to establish the flame, whereas titanium tetraisopropoxide is used as the precursor for TiO2. The nanoparticles are characterized using high-resolution transmission electron microscopy, with elemental mapping (of C, O, and Ti), X-ray diffraction, Raman spectroscopy, and thermogravimetric analysis. The growth of pure anatase TiO2 nanoparticles occurs when Ar and H2 are used as the precursor carrier gas, while the growth of carbon-coated nanoparticles ensues when Ar and ethylene (C2H4) are used as the precursor carrier gas. A uniform coating of 3-5nm of carbon is observed around TiO2 particles. The growth of highly crystalline TiO2 nanoparticles is dependent on the gas flow rate of the precursor carrier and amorphous particles are observed at high flow rates. Carbon coating occurs only on crystalline nanoparticles, suggesting a possible growth mechanism of carbon-coated TiO2 nanoparticles. © 2013 The Combustion Institute.

  5. Tuning of the electro-mechanical behavior of the cellular carbon nanotube structures with nanoparticle dispersions

    International Nuclear Information System (INIS)

    The mechanical and electrical characteristics of cellular network of the carbon nanotubes (CNT) impregnated with metallic and nonmetallic nanoparticles were examined simultaneously by employing the nanoindentation technique. Experimental results show that the nanoparticle dispersion not only enhances the mechanical strength of the cellular CNT by two orders of magnitude but also imparts variable nonlinear electrical characteristics; the latter depends on the contact resistance between nanoparticles and CNT, which is shown to depend on the applied load while indentation. Impregnation with silver nanoparticles enhances the electrical conductance, the dispersion with copper oxide and zinc oxide nanoparticles reduces the conductance of CNT network. In all cases, a power law behavior with suppression in the differential conductivity at zero bias was noted, indicating electron tunneling through the channels formed at the CNT-nanoparticle interfaces. These results open avenues for designing cellular CNT foams with desired electro-mechanical properties and coupling

  6. Effect of Cationic and Anionic Surfactants on the Application of Calcium Carbonate Nanoparticles in Paper Coating

    CERN Document Server

    Barhoum, Ahmed; Abou-Zaied, Ragab Esmail; Rehan, Mohamed; Dufour, Thierry; Hill, Gavin; Dufresne, Alain

    2016-01-01

    Modification of calcium carbonate particles with surfactant significantly improves the properties of the calcium carbonate coating on paper. Unmodified and CTAB and oleate-modified calcium carbonate nanoparticles were prepared using the wet carbonation technique for paper coating. CTAB (cationic surfactant) and sodium oleate (anionic surfactant) were used to modify the size, morphology, and surface properties of the precipitated nanoparticles. The obtained particles were characterized by XRD, FT-IR spectroscopy, zeta potential measurements, TGA and TEM. Coating colors were formulated from the prepared unmodified and modified calcium carbonates and examined by creating a thin coating layer on reference paper. The effect of calcium carbonate particle size and surface modification on paper properties, such as coating thickness, coating weight, surface roughness, air permeability, brightness, whiteness, opacity, and hydrophobicity, were investigated and compared with GCC calcium carbonate-coated papers. The obtai...

  7. Relation of Whole Blood Carboxyhemoglobin Concentration to Ambient Carbon Monoxide Exposure Estimated Using Regression

    OpenAIRE

    Rudra, Carole B.; Williams, Michelle A.; Sheppard, Lianne; Koenig, Jane Q.; Schiff, Melissa A.; Frederick, Ihunnaya O; Dills, Russell

    2010-01-01

    Exposure to carbon monoxide (CO) and other ambient air pollutants is associated with adverse pregnancy outcomes. While there are several methods of estimating CO exposure, few have been evaluated against exposure biomarkers. The authors examined the relation between estimated CO exposure and blood carboxyhemoglobin concentration in 708 pregnant western Washington State women (1996–2004). Carboxyhemoglobin was measured in whole blood drawn around 13 weeks’ gestation. CO exposure during the mon...

  8. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Jackson, Petra;

    2013-01-01

    Inhalation of particles has been shown to induce mutations in the male germline in mice following both prenatal and adult exposures in several experiments. In contrast, the effects of particles on female germ cell mutagenesis are not well established. Germline mutations are induced during active...... cell division, which occurs during fetal development in females. We investigated the effects of prenatal exposure to carbon black nanoparticles (CB) on induction of mutations in the female mouse germline during fetal development, spanning the critical developmental stages of oogenesis. Pregnant C57BL/6...... mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring....

  9. Potential in vitro model for testing the effect of exposure to nanoparticles on the lung alveolar epithelial barrier

    Directory of Open Access Journals (Sweden)

    Raymond Derk

    2015-03-01

    Full Text Available Pulmonary barrier function plays a pivotal role in protection from inhaled particles. However, some nano-scaled particles, such as carbon nanotubes (CNT, have demonstrated the ability to penetrate this barrier in animal models, resulting in an unusual, rapid interstitial fibrosis. To delineate the underlying mechanism and specific bio-effect of inhaled nanoparticles in respiratory toxicity, models of lung epithelial barriers are required that allow accurate representation of in vivo systems; however, there is currently a lack of consistent methods to do so. Thus, this work demonstrates a well-characterized in vitro model of pulmonary barrier function using Calu-3 cells, and provides the experimental conditions required for achieving tight junction complexes in cell culture, with trans-epithelial electrical resistance measurement used as a biosensor for proper barrier formation and integrity. The effects of cell number and serum constituents have been examined and we found that changes in each of these parameters can greatly affect barrier formation. Our data demonstrate that use of 5.0 × 104 Calu-3 cells/well in the Transwell cell culture system, with 10% serum concentrations in culture media is optimal for assessing epithelial barrier function. In addition, we have utilized CNT exposure to analyze the dose-, time-, and nanoparticle property-dependent alterations of epithelial barrier permeability as a means to validate this model. Such high throughput in vitro cell models of the epithelium could be used to predict the interaction of other nanoparticles with lung epithelial barriers to mimic respiratory behavior in vivo, thus providing essential tools and bio-sensing techniques that can be uniformly employed.

  10. Effect of annealing on the structure of carbon onions and the annealed carbon coated Ni nanoparticles fabricated by chemical vapor deposition

    International Nuclear Information System (INIS)

    Structural evolutions of carbon onions and carbon coated nanocrystals of nickel during annealing process were investigated. X-ray diffraction, Raman and transmission electron microscope were used to investigate their structural variation. The results showed that annealing (700 deg. C) of the carbon onions resulted in the shrinkage of hollow core of carbon onions and reduction of the interlayer spacing between carbon onion shells. And the compressed onion structure took a perfect spheroidal shape. However, the structure of the annealed carbon coated Ni nanoparticles presented that the Ni nanoparticles (5-30 nm) escaped from carbon encapsulation and congregated to large Ni particles (30-180 nm), and the carbon coating was disintegrated to small disorder graphite pieces. When the Ni was removed from the carbon coated Ni nanoparticles and then was annealed at 700 deg. C for 4 h, it was found that these hollow carbon onions presented the similar structural evolution as the above carbon onions

  11. Hydrothermal carbon spheres containing silicon nanoparticles: synthesis and lithium storage performance.

    Science.gov (United States)

    Demir Cakan, Rezan; Titirici, Maria-Magdalena; Antonietti, Markus; Cui, Guanglei; Maier, Joachim; Hu, Yong-Sheng

    2008-08-28

    Spherically shaped carbon/silicon nanocomposites have been obtained in a one-step procedure using hydrothermal carbonization of glucose in the presence of commercially available silicon nanoparticles and have been tested electrochemically as an anode material for lithium-ion batteries. PMID:18685768

  12. Efficient and Controllable Silver Nanoparticles Generation in Ion-exchanged Soda-lime Glasses by Simultaneous Heat Treatment and UV Exposure

    OpenAIRE

    Goutaland, François; Marin, Emmanuel; Gagnaire, Henri; Michalon, Jean-Yves; Boukenter, Aziz

    2008-01-01

    In this paper, we report on the space-selective precipitation of silver nanoparticles in ion-exchanged silica-based glasses, by simultaneous continuous wave UV exposure and heat treatment. Changes in the absorption spectrum of the glass are explained by the growth of the silver nanoparticles when increasing the UV power density and the annealing temperature. Nanoparticles of average diameter 40 nm have been observed, whereas silver nanoparticles formed under laser exposure at room temperature...

  13. Production of palladium nanoparticles supported on multiwalled carbon nanotubes by gamma irradiation

    International Nuclear Information System (INIS)

    Palladium nanoparticles were produced and supported on multiwalled carbon nanotubes (MWCNT) by gamma irradiation. A solution with a specific ratio of 2:1 of water-isopropanol was prepared and mixed with palladium chloride and the surfactant sodium dodecyl sulfate (SDS). The gamma radiolysis of water ultimately produces Pd metallic particles that serve as nucleation seeds. Isopropanol is used as an ion scavenger to balance the reaction, and the coalescence of the metal nanoparticles was controlled by the addition of SDS as a stabilizer. The size and distribution of nanoparticles on the carbon nanotubes (CNT) were studied at different surfactant concentrations and radiation doses. SEM, STEM and XPS were used for morphological, chemical and structural characterization of the nanostructure. Nanoparticles obtained for doses between 10 and 40 kGy, ranged in size 5-30 nm. The smaller nanoparticles were obtained at the higher doses and vice versa. Histograms of particle size distributions at different doses are presented. - Highlights: → Palladium nanoparticles deposited on multiwalled carbon nanotubes by gamma irradiation. → Dependence of size and distribution of the nanoparticles on dose and surfactant evaluated. → Interaction of Pd and CNTs explained by the formation of Pd-O on the surface of the CNTs. → Distribution of palladium particles with an average size of 5 nm obtained at 40 kGy and 0.07 M SDS.

  14. Electrochemical synthesis of elongated noble metal nanoparticles, such as nanowires and nanorods, on high-surface area carbon supports

    Energy Technology Data Exchange (ETDEWEB)

    Adzic, Radoslav; Blyznakov, Stoyan; Vukmirovic, Miomir

    2015-08-04

    Elongated noble-metal nanoparticles and methods for their manufacture are disclosed. The method involves the formation of a plurality of elongated noble-metal nanoparticles by electrochemical deposition of the noble metal on a high surface area carbon support, such as carbon nanoparticles. Prior to electrochemical deposition, the carbon support may be functionalized by oxidation, thus making the manufacturing process simple and cost-effective. The generated elongated nanoparticles are covalently bound to the carbon support and can be used directly in electrocatalysis. The process provides elongated noble-metal nanoparticles with high catalytic activities and improved durability in combination with high catalyst utilization since the nanoparticles are deposited and covalently bound to the carbon support in their final position and will not change in forming an electrode assembly.

  15. Exposure to Carbon Nanotube Material: Assessment of Nanotube Cytotoxicity Using Human Keratinocyte Cells

    Science.gov (United States)

    Shvedova, Anna A.; Castranova, Vincent; Kisin, Elena R.; Schwegler-Berry, Diane; Murray, Ashley R.; Gandelsman, Vadim Z.; Maynard, Andrew; Baron, Paul

    2003-01-01

    Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical, and thermal properties, carbon nanotubes are important for novel applications in the electronics, aerospace, and computer industries. Exposure to graphite and carbon materials has been associated with increased incidence of skin diseases, such as carbon fiber dermatitis, hyperkeratosis, and naevi. We investigated adverse effects of single-wall carbon nanotubes (SWCNT) using a cell culture of immortalized human epidermal keratinocytes (HaCaT). After 18 h of exposure of HaCaT to SWCNT, oxidative stress and cellular toxicity were indicated by formation of free radicals, accumulation of peroxidative products, antioxidant depletion, and loss of cell viability. Exposure to SWCNT also resulted in ultrastructural and morphological changes in cultured skin cells. These data indicate that dermal exposure to unrefined SWCNT may lead to dermal toxicity due to accelerated oxidative stress in the skin of exposed workers.

  16. Experimental techniques for the characterization of carbon nanoparticles – a brief overview

    Directory of Open Access Journals (Sweden)

    Wojciech Kempiński

    2014-10-01

    Full Text Available The review of four experimental methods: X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance and four-point electrical conductivity measurements is presented to characterize carbon nanoparticles. Two types of carbon nanoparticle systems are discussed: one comprising the powder of individual carbon nanoparticles and the second as a structurally interconnected nanoparticle matrix in the form of a fiber. X-ray diffraction and Raman spectroscopy reveal the atomic structure of the carbon nanoparticles and allow for observation of the changes in the quasi-graphitic ordering induced by ultrasonic irradiation and with the so-called quasi-high pressure effect under adsorption conditions. Structural changes have strong influence on the electronic properties, especially the localization of charge carriers within the nanoparticles, which can be observed with the EPR technique. This in turn can be well-correlated with the four-point electrical conductivity measurements which directly show the character of the charge carrier transport within the examined structures.

  17. Fe-inserted and shell-shaped carbon nanoparticles by cluster-mediated laser pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fleaca, C.T., E-mail: claudiufleaca@yahoo.com [Laser Photochemistry Laboratory, National Institute for Lasers, Plasma and Radiation Physics (NILPRP), P.O. Box MG 36, R-077125 Bucharest-Magurele (Romania); Dumitrache, F.; Morjan, I.; Alexandrescu, R.; Sandu, I.; Luculescu, C.; Birjega, S. [Laser Photochemistry Laboratory, National Institute for Lasers, Plasma and Radiation Physics (NILPRP), P.O. Box MG 36, R-077125 Bucharest-Magurele (Romania); Prodan, G. [Ovidius University of Constanta, 124 Mamaia Bd., Constanta (Romania); Stamatin, I. [3 Nano-SAE Research Center, University of Bucharest, P.O. Box MG-38, R-077125 Bucharest-Magurele (Romania)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Iron-inserted carbon nanoparticles were obtained by laser pyrolysis technique. Black-Right-Pointing-Pointer Two different structures (shell-shape and turbostratic) were found in the same experiment. Black-Right-Pointing-Pointer Increasing the pressure causes the increasing in carbon crystallinity/decreasing the Fe content. Black-Right-Pointing-Pointer Iron nanoinclusions are protected from oxidation by the carbon matrix. Black-Right-Pointing-Pointer Magnetism-related applications of these nanoparticles in life sciences are proposed. - Abstract: We report here the high-yield continuous synthesis of carbon nanoparticles with and without Fe content by laser pyrolysis technique. The laser beam decomposes (via C{sub 2}H{sub 4} sensitizer) the Fe(CO){sub 5} as Fe clusters which absorb themselves the laser radiation. They trigger the fast carbon particles formation by exothermic dehydrogenation/polymerization of the surrounded C{sub 2}H{sub 2} molecules. This combination between Fe clusters and C{sub 2}H{sub 2} generates nanoparticles with unusual structure. Depending on the gas pressure in the reaction chamber, two kinds of nanoparticles were obtained: at lower pressure, 30-40 nm diameter particles with a defective structure, part of them crowded with Fe clusters (3-6 nm) and two types of nanoparticles (around 50-60 nm) at the highest pressure. Some of them have a shell-shape structure, presenting a distinct envelope, other with a turbostratic arrangement, and few containing one or several smaller (3-20 nm) Fe nanoparticles trapped inside. We consider that these particular structures of our nanoparticles may be useful in applications such as MRI applications, drug delivery or catalysts.

  18. Pulmotoxicological effects caused by long-term titanium dioxide nanoparticles exposure in mice

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Qingqing; Tan, Danning; Ze, Yuguan; Sang, Xuezi [Medical College of Soochow University, Suzhou 215123 (China); Liu, Xiaorun [Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009 (China); Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing 210009 (China); Gui, Suxin; Cheng, Zhe; Cheng, Jie; Hu, Renping; Gao, Guodong; Liu, Gan; Zhu, Min; Zhao, Xiaoyang; Sheng, Lei; Wang, Ling [Medical College of Soochow University, Suzhou 215123 (China); Tang, Meng, E-mail: tm@seu.edu.cn [Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009 (China); Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing 210009 (China); Hong, Fashui, E-mail: Hongfsh_cn@sina.com [Medical College of Soochow University, Suzhou 215123 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Exposure to TiO{sub 2} NPs could be significantly accumulated in the lung. Black-Right-Pointing-Pointer Exposure to TiO{sub 2} NPs caused pulmonary injury in mice. Black-Right-Pointing-Pointer Exposure to TiO{sub 2} NP promoted the expression of inflammatory cytokines in the lung. Black-Right-Pointing-Pointer Exposure to TiO{sub 2} NP caused ROS overproduction in the lung. - Abstract: Exposure to titanium dioxide nanoparticles (TiO{sub 2} NPs) has been demonstrated to result in pulmonary inflammation in animals; however, very little is known about the molecular mechanisms of pulmonary injury due to TiO{sub 2} NPs exposure. The aim of this study was to evaluate the oxidative stress and molecular mechanism associated with pulmonary inflammation in chronic lung toxicity caused by the intratracheal instillation of TiO{sub 2} NPs for 90 consecutive days in mice. Our findings suggest that TiO{sub 2} NPs are significantly accumulated in the lung, leading to an obvious increase in lung indices, inflammation and bleeding in the lung. Exposure to TiO{sub 2} NPs significantly increased the accumulation of reactive oxygen species and the level of lipid peroxidation, and decreased antioxidant capacity in the lung. Furthermore, TiO{sub 2} NPs exposure activated nuclear factor-{kappa}B, increased the levels of tumor necrosis factor-{alpha}, cyclooxygenase-2, heme oxygenase-1, interleukin-2, interleukin-4, interleukin-6, interleukin-8, interleukin-10, interleukin-18, interleukin-1{beta}, and CYP1A1 expression. However, TiO{sub 2} NPs exposure decreased NF-{kappa}B-inhibiting factor and heat shock protein 70 expression. Our results suggest that the generation of pulmonary inflammation caused by TiO{sub 2} NPs in mice is closely related to oxidative stress and the expression of inflammatory cytokines.

  19. Shifts in the metabolic function of a benthic estuarine microbial community following a single pulse exposure to silver nanoparticles

    International Nuclear Information System (INIS)

    The increasing use of silver nanoparticles (AgNPs) as a biocidal agent and their potential accumulation in sediments may threaten non-target natural environmental bacterial communities. In this study a microcosm approach was established to investigate the effects of well characterized OECD AgNPs (NM-300) on the function of the bacterial community inhabiting marine estuarine sediments (salinity 31‰). The results showed that a single pulse of NM-300 AgNPs (1 mg L−1) that led to sediment concentrations below 6 mg Ag kg−1 dry weight inhibited the bacterial utilization of environmentally relevant carbon substrates. As a result, the functional diversity changed, but recovered after 120 h under the experimental conditions. This microcosm study suggests that AgNPs under environmentally relevant experimental conditions can negatively affect bacterial function and provides an insight into the understanding of the bacterial community response and resilience to AgNPs exposure, important for informing relevant regulatory measures. - Highlights: • AgNPs affected the bacterial community function in estuarine marine sediments. • AgNPs inhibited the bacterial utilization of environmentally relevant substrates. • Heterotrophic bacterial groups showed resilience to AgNPs after 120 h exposure. • AgNPs did not affect the bacterial community structure in sediments. - AgNPs inhibited the bacterial utilization of environmentally relevant substrates and caused temporary shifts in the bacterial functional diversity in marine estuarine sediments

  20. Novel object recognition ability in female mice following exposure to nanoparticle-rich diesel exhaust

    International Nuclear Information System (INIS)

    Recently, our laboratory reported that exposure to nanoparticle-rich diesel exhaust (NRDE) for 3 months impaired hippocampus-dependent spatial learning ability and up-regulated the expressions of memory function-related genes in the hippocampus of female mice. However, whether NRDE affects the hippocampus-dependent non-spatial learning ability and the mechanism of NRDE-induced neurotoxicity was unknown. Female BALB/c mice were exposed to clean air, middle-dose NRDE (M-NRDE, 47 μg/m3), high-dose NRDE (H-NRDE, 129 μg/m3), or filtered H-NRDE (F-DE) for 3 months. We then investigated the effect of NRDE exposure on non-spatial learning ability and the expression of genes related to glutamate neurotransmission using a novel object recognition test and a real-time RT-PCR analysis, respectively. We also examined microglia marker Iba1 immunoreactivity in the hippocampus using immunohistochemical analyses. Mice exposed to H-NRDE or F-DE could not discriminate between familiar and novel objects. The control and M-NRDE-exposed groups showed a significantly increased discrimination index, compared to the H-NRDE-exposed group. Although no significant changes in the expression levels of the NMDA receptor subunits were observed, the expression of glutamate transporter EAAT4 was decreased and that of glutamic acid decarboxylase GAD65 was increased in the hippocampus of H-NRDE-exposed mice, compared with the expression levels in control mice. We also found that microglia activation was prominent in the hippocampal area of the H-NRDE-exposed mice, compared with the other groups. These results indicated that exposure to NRDE for 3 months impaired the novel object recognition ability. The present study suggests that genes related to glutamate metabolism may be involved in the NRDE-induced neurotoxicity observed in the present mouse model. -- Highlights: ► The effects of nanoparticle-induced neurotoxicity remain unclear. ► We investigated the effect of exposure to nanoparticles on

  1. Novel object recognition ability in female mice following exposure to nanoparticle-rich diesel exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Win-Shwe, Tin-Tin, E-mail: tin.tin.win.shwe@nies.go.jp [Center for Environmental Health Sciences, National Institute for Environmental Studies, 16‐2 Onogawa, Tsukuba, Ibaraki 305‐8506 (Japan); Fujimaki, Hidekazu; Fujitani, Yuji; Hirano, Seishiro [Center for Environmental Risk Research, National Institute for Environmental Studies, 16‐2 Onogawa, Tsukuba, Ibaraki 305‐8506 (Japan)

    2012-08-01

    Recently, our laboratory reported that exposure to nanoparticle-rich diesel exhaust (NRDE) for 3 months impaired hippocampus-dependent spatial learning ability and up-regulated the expressions of memory function-related genes in the hippocampus of female mice. However, whether NRDE affects the hippocampus-dependent non-spatial learning ability and the mechanism of NRDE-induced neurotoxicity was unknown. Female BALB/c mice were exposed to clean air, middle-dose NRDE (M-NRDE, 47 μg/m{sup 3}), high-dose NRDE (H-NRDE, 129 μg/m{sup 3}), or filtered H-NRDE (F-DE) for 3 months. We then investigated the effect of NRDE exposure on non-spatial learning ability and the expression of genes related to glutamate neurotransmission using a novel object recognition test and a real-time RT-PCR analysis, respectively. We also examined microglia marker Iba1 immunoreactivity in the hippocampus using immunohistochemical analyses. Mice exposed to H-NRDE or F-DE could not discriminate between familiar and novel objects. The control and M-NRDE-exposed groups showed a significantly increased discrimination index, compared to the H-NRDE-exposed group. Although no significant changes in the expression levels of the NMDA receptor subunits were observed, the expression of glutamate transporter EAAT4 was decreased and that of glutamic acid decarboxylase GAD65 was increased in the hippocampus of H-NRDE-exposed mice, compared with the expression levels in control mice. We also found that microglia activation was prominent in the hippocampal area of the H-NRDE-exposed mice, compared with the other groups. These results indicated that exposure to NRDE for 3 months impaired the novel object recognition ability. The present study suggests that genes related to glutamate metabolism may be involved in the NRDE-induced neurotoxicity observed in the present mouse model. -- Highlights: ► The effects of nanoparticle-induced neurotoxicity remain unclear. ► We investigated the effect of exposure to

  2. Growth and morphology of carbon nanostructures on nickel oxide nanoparticles in catalytic chemical vapor deposition

    Science.gov (United States)

    Jana, M.; Sil, A.; Ray, S.

    2014-07-01

    The present study explores the conditions favorable for the growth of cylindrical carbon nanostructures such as multi-walled carbon nanotube (MWCNT) and carbon nanofiber by catalytic chemical vapor deposition (CCVD) method using nickel oxide-based catalyst nanoparticles of different average sizes as well as different levels of doping by copper oxide. The role of doping and the average size have been related to the observed melting behavior of nanoparticles of nickel oxide by thermal and diffraction analysis, and the importance of melting has been highlighted in the context of growth of cylindrical nanostructures. In the reducing environment prevailing in the CCVD chamber due to decomposition of flowing acetylene gas at elevated temperature, there is extensive reduction of oxide nanoparticles. Lack of melting and faster flow of carbon-bearing gases favor the formation of a carbon deposit cover over the catalyst nanoparticles giving rise to the formation of nanobeads. Melting allows rapid diffusion of carbon from the surface to inside catalyst particles, and reduced flow of gas lowers the rate of carbon deposit, both creating conditions favorable for the formation of cylindrical nanostructures, which grows around the catalyst particles. Smaller particle size and lower doping favor growth of MWCNT, while growth of fiber is commonly observed on larger particles having relatively higher level of doping.

  3. "Homeopathic" palladium nanoparticle catalysis of cross carbon-carbon coupling reactions.

    Science.gov (United States)

    Deraedt, Christophe; Astruc, Didier

    2014-02-18

    Catalysis by palladium derivatives is now one of the most important tools in organic synthesis. Whether researchers design palladium nanoparticles (NPs) or nanoparticles occur as palladium complexes decompose, these structures can serve as central precatalysts in common carbon-carbon bond formation. Palladium NPs are also valuable alternatives to molecular catalysts because they do not require costly and toxic ligands. In this Account, we review the role of "homeopathic" palladium catalysts in carbon-carbon coupling reactions. Seminal studies from the groups of Beletskaya, Reetz, and de Vries showed that palladium NPs can catalyze Heck and Suzuki-Miyaura reactions with aryl iodides and, in some cases, aryl bromides at part per million levels. As a result, researchers coined the term "homeopathic" palladium catalysis. Industry has developed large-scale applications of these transformations. In addition, chemists have used Crooks' concept of dendrimer encapsulation to set up efficient nanofilters for Suzuki-Miyaura and selective Heck catalysis, although these transformations required high PdNP loading. With arene-centered, ferrocenyl-terminated dendrimers containing triazolyl ligands in the tethers, we designed several generations of dendrimers to compare their catalytic efficiencies, varied the numbers of Pd atoms in the PdNPs, and examined encapsulation vs stabilization. The catalytic efficiencies achieved "homeopathic" (TON = 540 000) behavior no matter the PdNP size and stabilization type. The TON increased with decreasing the Pd/substrate ratio, which suggested a leaching mechanism. Recently, we showed that water-soluble arene-centered dendrimers with tri(ethylene glycol) (TEG) tethers stabilized PdNPs involving supramolecular dendritic assemblies because of the interpenetration of the TEG branches. Such PdNPs are stable and retain their "homeopathic" catalytic activities for Suzuki-Miyaura reactions for months. (TONs can reach 2.7 × 10(6) at 80 °C for aryl

  4. Synthesis of carbon nanoparticles from commercially available liquified petroleum gas

    Science.gov (United States)

    Nandiyanto, A. B. D.; Fadhlulloh, M. A.; Rahman, T.; Mudzakir, A.

    2016-04-01

    The aim of this study was to synthesize carbon nanoparticles (CNPs) from commercially available liquefied petroleum gas (LPG). In the research procedure, LPG was reacted with air to construct CNPs. To confirm the successful synthesis of CNPs, we conducted several sample analyses: Gas Chromatography-Mass Spectrometry (GC-MS), Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), and Infrared Spectra (FTIR). We also varied LPG and oxygen mole ratios at 0.8; 2.4; 4.8; and 7.2. The GC-MS results indicated the composition of LPG was propane (58.90%), isobutane (18.35%), butane (22.26%), and butane, 2-methyl (0.48%). The TEM results showed that the particles were spheres with sizes of between 25 and 35 nm. The sizes of particles were controllable, depending on the mole ratio. The XRD results showed mole ratios of LPG and oxygen of 0.80 and 2.40 were natural graphite, whereas the mole ratios of 4.80 and 7.20 were hexagonal graphite. FT-IR results showed CNPs have absorption peaks at wave number (i) 752 (C-H bend sp2); (ii) 835 (C=C); (iii) 1274 (C-O-C vibration); (iv) 1400 and 1600 (C-C stretch aromatic); (v) 2800 (C-H sp2); (vi) 2900 (CH sp3); (vii) 3100 (C-H aromatic); and (viii) 3400 cm-1 (O-H). From the FTIR analysis results, the sample contained allotrope graphite due to detection of peaks at 1400 and 1600 cm-1 (C-C stretch aromatic) and 3100 cm-1 (C-H aromatic).

  5. Synthesis of agarose-metal/semiconductor nanoparticles having superior bacteriocidal activity and their simple conversion to metal-carbon composites

    Indian Academy of Sciences (India)

    K K R Datta; B Srinivasan; H Balaram; M Eswaramoorthy

    2008-11-01

    Agarose, a naturally occurring biopolymer is used for the stabilization of metal, semiconductor nanoparticles. Ag and Cu nanoparticles stabilized in agarose matrix show excellent antibacterial activity against E. coli bacteria. The well dispersed metal nanoparticles within the agarose composite films can be readily converted to carbon-metal composites of catalytic importance.

  6. Exposure of cerium oxide nanoparticles to kidney bean shows disturbance in the plant defense mechanisms

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Kidney bean roots uptake nCeO2 primarily without biotransformation. • Cerium reached the root vascular tissues through gaps in the Casparian strip. • On longer exposure to high concentration, roots demonstrate stress response. • In leaves, guaiacol peroxidase plays a major role in ROS scavenging. - Abstract: Overwhelming use of engineered nanoparticles demands rapid assessment of their environmental impacts. The transport of cerium oxide nanoparticles (nCeO2) in plants and their impact on cellular homeostasis as a function of exposure duration is not well understood. In this study, kidney bean plants were exposed to suspensions of ∼8 ± 1 nm nCeO2 (62.5 to 500 mg/L) for 15 days in hydroponic conditions. Plant parts were analyzed for cerium accumulation after one, seven, and 15 days of nCeO2 exposure. The primary indicators of stress like lipid peroxidation, antioxidant enzyme activities, total soluble protein and chlorophyll contents were studied. Cerium in tissues was localized using scanning electron microscopy and synchrotron μ-XRF mapping, and the chemical forms were identified using μ-XANES. In the root epidermis, cerium was primarily shown to exist as nCeO2, although a small fraction (12%) was biotransformed to Ce(III) compound. Cerium was found to reach the root vascular tissues and translocate to aerial parts with time. Upon prolonged exposure to 500 mg nCeO2/L, the root antioxidant enzyme activities were significantly reduced, simultaneously increasing the root soluble protein by 204%. In addition, leaf's guaiacol peroxidase activity was enhanced with nCeO2 exposure in order to maintain cellular homeostasis

  7. Exposure of cerium oxide nanoparticles to kidney bean shows disturbance in the plant defense mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Sanghamitra [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Peralta-Videa, Jose R. [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Bandyopadhyay, Susmita [Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Castillo-Michel, Hiram [European Synchrotron Radiation Facility, B.P. 220-38043 Grenoble, Cedex (France); Hernandez-Viezcas, Jose-Angel [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Sahi, Shivendra [Department of Biology, Western Kentucky University, Bowling Green, KY 42101 (United States); Gardea-Torresdey, Jorge L., E-mail: jgardea@utep.edu [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States)

    2014-08-15

    Graphical abstract: - Highlights: • Kidney bean roots uptake nCeO{sub 2} primarily without biotransformation. • Cerium reached the root vascular tissues through gaps in the Casparian strip. • On longer exposure to high concentration, roots demonstrate stress response. • In leaves, guaiacol peroxidase plays a major role in ROS scavenging. - Abstract: Overwhelming use of engineered nanoparticles demands rapid assessment of their environmental impacts. The transport of cerium oxide nanoparticles (nCeO{sub 2}) in plants and their impact on cellular homeostasis as a function of exposure duration is not well understood. In this study, kidney bean plants were exposed to suspensions of ∼8 ± 1 nm nCeO{sub 2} (62.5 to 500 mg/L) for 15 days in hydroponic conditions. Plant parts were analyzed for cerium accumulation after one, seven, and 15 days of nCeO{sub 2} exposure. The primary indicators of stress like lipid peroxidation, antioxidant enzyme activities, total soluble protein and chlorophyll contents were studied. Cerium in tissues was localized using scanning electron microscopy and synchrotron μ-XRF mapping, and the chemical forms were identified using μ-XANES. In the root epidermis, cerium was primarily shown to exist as nCeO{sub 2}, although a small fraction (12%) was biotransformed to Ce(III) compound. Cerium was found to reach the root vascular tissues and translocate to aerial parts with time. Upon prolonged exposure to 500 mg nCeO{sub 2}/L, the root antioxidant enzyme activities were significantly reduced, simultaneously increasing the root soluble protein by 204%. In addition, leaf's guaiacol peroxidase activity was enhanced with nCeO{sub 2} exposure in order to maintain cellular homeostasis.

  8. Synthesis of Metal Nanoparticle-decorated Carbon Nanotubes under Ambient Conditions

    Science.gov (United States)

    Lin, Yi; Watson, Kent A.; Ghose, Sayata; Smith, Joseph G.; Connell, John W.

    2008-01-01

    This viewgraph presentation reviews the production of Metal Nanoparticle-decorated carbon Nanotubes. Multi-walled carbon nanotubes (MWCNTs) were efficiently decorated with metal nanoparticles (e.g. Ag, Pt, etc.) using the corresponding metal acetate in a simple mixing process without the need of chemical reagents or further processing. The conversion of acetate compounds to the corresponding metal reached over 90%, forming nanoparticles with average diameters less than 10 nm under certain conditions. The process was readily scalable allowing for the convenient preparation of multi-gram quantities of metal nanoparticle-decorated MWCNTs in a matter of a few minutes. These materials are under evaluation for a variety of electrical and catalytic applications. The preparation and characterization of these materials will be presented. The microscopic views of the processed MWCNTs are shown

  9. Gene expression profiling in rat kidney after intratracheal exposure to cadmium-doped nanoparticles

    International Nuclear Information System (INIS)

    While nephrotoxicity of cadmium is well documented, very limited information exists on renal effects of exposure to cadmium-containing nanomaterials. In this work, “omics” methodologies have been used to assess the action of cadmium-containing silica nanoparticles (Cd-SiNPs) in the kidney of Sprague-Dawley rats exposed intratracheally. Groups of animals received a single dose of Cd-SiNPs (1 mg/rat), CdCl2 (400 μg/rat) or 0.1 ml saline (control). Renal gene expression was evaluated 7 and 30 days post exposure by DNA microarray technology using the Agilent Whole Rat Genome Microarray 4x44K. Gene modulating effects were observed in kidney at both time periods after treatment with Cd-SiNPs. The number of differentially expressed genes being 139 and 153 at the post exposure days 7 and 30, respectively. Renal gene expression changes were also observed in the kidney of CdCl2-treated rats with a total of 253 and 70 probes modulated at 7 and 30 days, respectively. Analysis of renal gene expression profiles at day 7 indicated in both Cd-SiNP and CdCl2 groups downregulation of several cluster genes linked to immune function, oxidative stress, and inflammation processes. Differing from day 7, the majority of cluster gene categories modified by nanoparticles in kidney 30 days after dosing were genes implicated in cell regulation and apoptosis. Modest renal gene expression changes were observed at day 30 in rats treated with CdCl2. These results indicate that kidney may be a susceptible target for subtle long-lasting molecular alterations produced by cadmium nanoparticles locally instilled in the lung.

  10. Carbon black nanoparticles and vascular dysfunction in cultured endothelial cells and artery segments

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Mikkelsen, Lone; Folkmann, Janne K; Sheykhzade, Majid; Cao, Yi; Roursgaard, Martin; Loft, Steffen; Møller, Peter

    2012-01-01

    Exposure to small size particulates is regarded as a risk factor for cardiovascular disease. We investigated effects of exposure to nanosized carbon black (CB) in human umbilical vein endothelial cells (HUVECs) and segments of arteries from rodents. The CB exposure was associated with increased...

  11. Density function theory study of the adsorption and dissociation of carbon monoxide on tungsten nanoparticles.

    Science.gov (United States)

    Weng, Meng-Hsiung; Ju, Shin-Pon; Chen, Hsin-Tsung; Chen, Hui-Lung; Lu, Jian-Ming; Lin, Ken-Huang; Lin, Jenn-Sen; Hsieh, Jin-Yuan; Yang, Hsi-Wen

    2013-02-01

    The adsorption and dissociation properties of carbon monoxide (CO) molecule on tungsten W(n) (n = 10-15) nanoparticles have been investigated by density-functional theory (DFT) calculations. The lowest-energy structures for W(n) (n = 10-15) nanoparticles are found by the basin-hopping method and big-bang method with the modified tight-binding many-body potential. We calculated the corresponding adsorption energies, C-O bond lengths and dissociation barriers for adsorption of CO on nanoparticles. The electronic properties of CO on nanoparticles are studied by the analysis of density of state and charge density. The characteristic of CO on W(n) nanoparticles are also compared with that of W bulk. PMID:23646573

  12. In situ heating and tomography of gold nanoparticles on carbon structures

    International Nuclear Information System (INIS)

    A series of thermally mediated dynamic (in situ) experiments in the transmission electron microscope (TEM) have been performed, in order to obtain improved understanding and control of the ripening and migration processes of gold nanoparticles on multi-wall carbon nanotubes (MWNTs). In particular, post-heating tomography was used to appraise the resultant dispersion of the nanoparticles within these three-dimensional (3D) composite structures

  13. Layer-by-layer Assembly of Noble Metal Nanoparticles on Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    CHEN Da; ZHENG Long-Zhen

    2008-01-01

    Silver,gold,platinum and palladium nanoparticles were initially prepared in the AOT[sodium bis(2-ethylhexyl)-sulfosuccinate]micelle and characterized by ultraviolet-visible spectroscopy,transmission electron macroscopy,X-ray diffraction,Fourier transform-infrared spectroscopy,and zeta potential analysis.The negatively charged Pt nanoparticles were self-assembled on a glassy carbon electrode by a layer-by-layer method and the modified electrode electrocatalytic reactivity toward methanol oxidation was studied.

  14. Application of Silver and Silver Oxide Nanoparticles Impregnated on Activated Carbon to the Degradation of Bromate.

    Science.gov (United States)

    Choi, J S; Lee, H; Park, Y K; Kim, S J; Kim, B J; An, K H; Kim, B H; Jung, S C

    2016-05-01

    Silver and silver oxide nanoparticles were impregnated on the surface of powdered activated carbon (PAC) using a single-step liquid phase plasma (LPP) method. Spherical silver and silver oxide nanoparticles of 20 to 100 nm size were dipersed evenly on the surface of PAC. The impregnated PAC exhibited a higher activity for the decomposition of bromate than bare PAC. The XPS, Raman and EDX analyses showed that the Ag/PAC composites synthesized by the LPP process. PMID:27483780

  15. Functionalization and Area-Selective Deposition of Magnetic Carbon-Coated Iron Nanoparticles from Solution

    OpenAIRE

    Erika Widenkvist; Oscar Alm; Mats Boman; Ulf Jansson; Helena Grennberg

    2011-01-01

    A route to area-selective deposition of carbon-coated iron nanoparticles, involving chemical modification of the surface of the particles, is described. Partial oxidative etching of the coating introduces carboxylic groups, which then are esterified. The functionalized particles can be selectively deposited on the Si areas of Si/SiO2 substrates by a simple dipping procedure. Nanoparticles and nanoassemblies have been analyzed using SEM, TEM, and XPS.

  16. Effects of exposure to zinc oxide nanoparticles in freshwater mussels in the presence of municipal effluents

    OpenAIRE

    Gagnon, C; M Pilote; P Turcotte; André, C.; F Gagné

    2016-01-01

    Zinc oxide (nano-ZnO) nanoparticles are used in the production of transparent sunscreens and cosmetics, which are released into surface waters and municipal wastewater effluent. The purpose of this study was to examine the toxicity of nano-ZnO in the presence of municipal effluents to freshwater mussels Elliptio complanata. Mussels were exposed for 21 days at 15 o C to nano-ZnO and ZnCl2 in the presence of 10 % dilution of primary-treated municipal effluent. After the exposure ...

  17. Oxidative DNA damage from nanoparticle exposure and its application to workers' health: a literature review.

    Science.gov (United States)

    Rim, Kyung-Taek; Song, Se-Wook; Kim, Hyeon-Yeong

    2013-12-01

    The use of nanoparticles (NPs) in industry is increasing, bringing with it a number of adverse health effects on workers. Like other chemical carcinogens, NPs can cause cancer via oxidative DNA damage. Of all the molecules vulnerable to oxidative modification by NPs, DNA has received the greatest attention, and biomarkers of exposure and effect are nearing validation. This review concentrates on studies published between 2000 and 2012 that attempted to detect oxidative DNA damage in humans, laboratory animals, and cell lines. It is important to review these studies to improve the current understanding of the oxidative DNA damage caused by NP exposure in the workplace. In addition to examining studies on oxidative damage, this review briefly describes NPs, giving some examples of their adverse effects, and reviews occupational exposure assessments and approaches to minimizing exposure (e.g., personal protective equipment and engineering controls such as fume hoods). Current recommendations to minimize exposure are largely based on common sense, analogy to ultrafine material toxicity, and general health and safety recommendations. PMID:24422173

  18. Multifunctional nanocomposites of carbon nanotubes and nanoparticles formed via vacuum filtration

    Science.gov (United States)

    Hersam, Mark C; Ostojic, Gordana; Liang, Yu Teng

    2013-10-22

    In one aspect, the present invention provides a method of forming a film of nanocomposites of carbon nanotubes (CNTs) and platinum (Pt) nanoparticles. In one embodiment, the method includes the steps of (a) providing a first solution that contains a plurality of CNTs, (b) providing a second solution that contains a plurality of Pt nanoparticles, (c) combining the first solution and the second solution to form a third solution, and (d) filtering the third solution through a nanoporous membrane using vacuum filtration to obtain a film of nanocomposites of CNTs and Pt nanoparticles.

  19. Decorating multi-walled carbon nanotubes with nickel nanoparticles for selective hydrogenation of citral

    International Nuclear Information System (INIS)

    The nanocomposites of multi-walled carbon nanotubes (MWNTs) decorated with nickel nanoparticles were conveniently prepared by a chemical reduction of nickel salt in the present of poly(acrylic acid) grafted MWNTs (PAA-g-MWNTs). Due to the strong interaction between Ni2+ and -COOH, PAA-g-MWNTs became an excellent supporting material for Ni nanoparticles. The morphology and distribution of Ni nanoparticles on the surface of MWNTs were greatly influenced by the reduction temperatures, the experimental results also showed that the distribution of Ni nanoparticles was greatly improved while the MWNTs were modified by poly(acrylic acid) (PAA). The hydrogenation activity and selectivity of MWNTs decorated with Ni nanoparticles (Ni-MWNTs) for α, β-unsaturated aldehyde (citral) were also studied, and the experimental results showed that the citronellal, an important raw material for flavoring and perfumery industries, is the favorable product with a percentage as high as 86.9%, which is 7 times higher than that of catalyst by Ni-supported active carbon (Ni-AC). - Abstract: Nickel nanoparticles decorated multi-walled carbon nanotubes (Ni-MWNTs) nanocomposites were conveniently prepared by a chemical reduction of nickel salt in the present of poly(acrylic acid) grafted MWNTs (PAA-g-MWNTs). These nanocomposites possessed excellent catalytic activity and selectivity for hydrogenation of citral.

  20. Magnesium oxide nanoparticles on green activated carbon as efficient CO{sub 2} adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wan Isahak, Wan Nor Roslam; Ramli, Zatil Amali Che; Mohamed Hisham, Mohamed Wahab; Yarmo, Mohd Ambar [Low Carbon Economy (LCE) Research Group, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2013-11-27

    This study was focused on carbon dioxide (CO{sub 2}) adsorption ability using Magnesium oxide (MgO) nanoparticles and MgO nanoparticles supported activated carbon based bamboo (BAC). The suitability of MgO as a good CO{sub 2} adsorbent was clarified using Thermodynamic considerations (Gibbs-Helmholtz relationship). The ΔH and ΔG of this reaction were − 117.5 kJ⋅mol{sup −1} and − 65.4 kJ⋅mol{sup −1}, respectively, at standard condition (298 K and 1 atm). The complete characterization of these adsorbent were conducted by using BET, XRD, FTIR, TEM and TPD−CO{sub 2}. The surface areas for MgO nanoparticles and MgO nanoparticles supported BAC were 297.1 m{sup 2}/g and 702.5 m{sup 2}/g, respectively. The MgO nanoparticles supported BAC shown better physical and chemical adsorption ability with 39.8 cm{sup 3}/g and 6.5 mmol/g, respectively. The combination of MgO nanoparticle and BAC which previously prepared by chemical method can reduce CO{sub 2} emissions as well as better CO{sub 2} adsorption behavior. Overall, our results indicate that nanoparticles of MgO on BAC posses unique surface chemistry and their high surface reactivity coupled with high surface area allowed them to approach the goal as an efficient CO{sub 2} adsorbent.

  1. Magnesium oxide nanoparticles on green activated carbon as efficient CO2 adsorbent

    International Nuclear Information System (INIS)

    This study was focused on carbon dioxide (CO2) adsorption ability using Magnesium oxide (MgO) nanoparticles and MgO nanoparticles supported activated carbon based bamboo (BAC). The suitability of MgO as a good CO2 adsorbent was clarified using Thermodynamic considerations (Gibbs-Helmholtz relationship). The ΔH and ΔG of this reaction were − 117.5 kJ⋅mol−1 and − 65.4 kJ⋅mol−1, respectively, at standard condition (298 K and 1 atm). The complete characterization of these adsorbent were conducted by using BET, XRD, FTIR, TEM and TPD−CO2. The surface areas for MgO nanoparticles and MgO nanoparticles supported BAC were 297.1 m2/g and 702.5 m2/g, respectively. The MgO nanoparticles supported BAC shown better physical and chemical adsorption ability with 39.8 cm3/g and 6.5 mmol/g, respectively. The combination of MgO nanoparticle and BAC which previously prepared by chemical method can reduce CO2 emissions as well as better CO2 adsorption behavior. Overall, our results indicate that nanoparticles of MgO on BAC posses unique surface chemistry and their high surface reactivity coupled with high surface area allowed them to approach the goal as an efficient CO2 adsorbent

  2. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    Directory of Open Access Journals (Sweden)

    Kumaresa P S Prasad, Dattatray S Dhawale, Thiripuranthagan Sivakumar, Salem S Aldeyab, Javaid S M Zaidi, Katsuhiko Ariga and Ajayan Vinu

    2011-01-01

    Full Text Available We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD, high-resolution scanning electron microscopy (HRSEM and high-resolution transmission electron microscopy (HRTEM. XRD results reveal that nanoporous carbons with embedded CuO nanoparticles exhibit a well-ordered mesoporous structure, whereas the nitrogen adsorption measurements indicate the presence of excellent textural characteristics such as high surface area, large pore volume and uniform pore size distribution. The amount of CuO nanoparticles in the nanochannels of the nanoporous carbon could be controlled by simply varying the Si/Cu molar ratio of the mesoporous silica template. Morphological characterization by SEM and TEM reveals that high-quality CuO nanoparticles are distributed homogeneously within the nanoporous carbon framework. The supercapacitance behavior of the CuO-loaded nanoporous carbons was investigated. The material with a small amount of CuO in the mesochannels and high surface area affords a maximum specific capacitance of 300 F g-1 at a 20 mV s-1 scan rate in an aqueous electrolyte solution. A supercapacitor containing the CuO-loaded nanoporous carbon is highly stable and exhibits a long cycle life with 91% specific capacitance retained after 1000 cycles.

  3. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    International Nuclear Information System (INIS)

    We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM). XRD results reveal that nanoporous carbons with embedded CuO nanoparticles exhibit a well-ordered mesoporous structure, whereas the nitrogen adsorption measurements indicate the presence of excellent textural characteristics such as high surface area, large pore volume and uniform pore size distribution. The amount of CuO nanoparticles in the nanochannels of the nanoporous carbon could be controlled by simply varying the Si/Cu molar ratio of the mesoporous silica template. Morphological characterization by SEM and TEM reveals that high-quality CuO nanoparticles are distributed homogeneously within the nanoporous carbon framework. The supercapacitance behavior of the CuO-loaded nanoporous carbons was investigated. The material with a small amount of CuO in the mesochannels and high surface area affords a maximum specific capacitance of 300 F g-1 at a 20 mV s-1 scan rate in an aqueous electrolyte solution. A supercapacitor containing the CuO-loaded nanoporous carbon is highly stable and exhibits a long cycle life with 91% specific capacitance retained after 1000 cycles.

  4. Ferric oxide nanoparticles decorated carbon nanotubes and carbon nanofibers: From synthesis to enhanced removal of phenol

    Directory of Open Access Journals (Sweden)

    Hamza A. Asmaly

    2015-09-01

    Full Text Available In this work, ferric oxide nanoparticle decorated carbon fibers and carbon nanotubes (CNF/Fe2O3 and CNT/Fe2O3 were synthesized and characterized by scanning electron microscopy (SEM, thermogravimetric analysis (TGA, energy dispersive X-ray spectroscopy (EDS, transmission electron microscopy (TEM, X-ray diffraction (XRD, zeta potential and BET surface area analyzer. The prepared nanocomposites were evaluated or the removal of phenol ions from aqueous solution. The effects of experimental parameters, such as shaking speed, pH, contact time, adsorbent dosage and initial concentration, were evaluated for the phenol removal efficiency. The adsorption experimental data were represented by both the Langmuir and Freundlich isotherm models. The Langmuir isotherm model best fitted the data on the adsorption of phenol, with a high correlation coefficient. The adsorption capacities, as determined by the Langmuir isotherm model were 0.842, 1.098, 1.684 and 2.778 mg/g for raw CNFs, raw CNTs, CNF–Fe2O3 and CNT–Fe2O3, respectively.

  5. Nanoparticles containing allotropes of carbon have genotoxic effects on glioblastoma multiforme cells.

    Science.gov (United States)

    Hinzmann, Mateusz; Jaworski, Sławomir; Kutwin, Marta; Jagiełło, Joanna; Koziński, Rafał; Wierzbicki, Mateusz; Grodzik, Marta; Lipińska, Ludwika; Sawosz, Ewa; Chwalibog, Andrè

    2014-01-01

    The carbon-based nanomaterial family consists of nanoparticles containing allotropes of carbon, which may have a number of interactions with biological systems. The objective of this study was to evaluate the toxicity of nanoparticles comprised of pristine graphene, reduced graphene oxide, graphene oxide, graphite, and ultradispersed detonation diamond in a U87 cell line. The scope of the work consisted of structural analysis of the nanoparticles using transmission electron microscopy, evaluation of cell morphology, and assessment of cell viability by Trypan blue assay and level of DNA fragmentation of U87 cells after 24 hours of incubation with 50 μg/mL carbon nanoparticles. DNA fragmentation was studied using single-cell gel electrophoresis. Incubation with nanoparticles containing the allotropes of carbon did not alter the morphology of the U87 cancer cells. However, incubation with pristine graphene and reduced graphene oxide led to a significant decrease in cell viability, whereas incubation with graphene oxide, graphite, and ultradispersed detonation diamond led to a smaller decrease in cell viability. The results of a comet assay demonstrated that pristine graphene, reduced graphene oxide, graphite, and ultradispersed detonation diamond caused DNA damage and were therefore genotoxic in U87 cells, whereas graphene oxide was not. PMID:24876774

  6. Atomic scale observation of oxygen delivery during silver-oxygen nanoparticle catalysed oxidation of carbon nanotubes

    Science.gov (United States)

    Yue, Yonghai; Yuchi, Datong; Guan, Pengfei; Xu, Jia; Guo, Lin; Liu, Jingyue

    2016-07-01

    To probe the nature of metal-catalysed processes and to design better metal-based catalysts, atomic scale understanding of catalytic processes is highly desirable. Here we use aberration-corrected environmental transmission electron microscopy to investigate the atomic scale processes of silver-based nanoparticles, which catalyse the oxidation of multi-wall carbon nanotubes. A direct semi-quantitative estimate of the oxidized carbon atoms by silver-based nanoparticles is achieved. A mechanism similar to the Mars-van Krevelen process is invoked to explain the catalytic oxidation process. Theoretical calculations, together with the experimental data, suggest that the oxygen molecules dissociate on the surface of silver nanoparticles and diffuse through the silver nanoparticles to reach the silver/carbon interfaces and subsequently oxidize the carbon. The lattice distortion caused by oxygen concentration gradient within the silver nanoparticles provides the direct evidence for oxygen diffusion. Such direct observation of atomic scale dynamics provides an important general methodology for investigations of catalytic processes.

  7. Investigation of Structure and Physico-Mechanical Properties of Composite Materials Based on Copper - Carbon Nanoparticles Powder Systems

    Directory of Open Access Journals (Sweden)

    Kovtun V.

    2015-04-01

    Full Text Available Physico-mechanical and structural properties of electrocontact sintered copper matrix- carbon nanoparticles composite powder materials are presented. Scanning electron microscopy revealed the influence of preliminary mechanical activation of the powder system on distribution of carbon nanoparticles in the metal matrix. Mechanical activation ensures mechanical bonding of nanoparticles to the surface of metal particles, thus giving a possibility for manufacture of a composite with high physico-mechanical properties.

  8. A theoretical study on the catalytic effect of nanoparticle confined in carbon nanotube

    Science.gov (United States)

    Qin, Wu; Li, Xin

    2011-01-01

    We investigated the catalytic effect of CuO nanoparticles confined in carbon nanotubes using molecular dynamics simulations and density functional theory calculations. Ozone decomposition and hydroxyl radical generation were used as the probe reactions to investigate the catalytic behavior of catalyst. The effects of the confined environment of carbon nanotubes induced more reactants into the channel. Interface interactions between reactants and CuO nanoparticles in the channel and charge transfer accelerated the decomposition of ozone into oxygen molecule and atomic oxygen species. The atomic oxygen species then interacted to water molecule to generate hydroxyl radicals, which were truly identified by electron paramagnetic resonance (EPR) technique.

  9. Semiconducting, Magnetic or Superconducting Nanoparticles encapsulated in Carbon Shells by RAPET method.

    Directory of Open Access Journals (Sweden)

    Aharon Gedanken

    2008-06-01

    Full Text Available An efficient, solvent-free, environmentally friendly, RAPET (Reactions under Autogenic Pressure at Elevated Temperaturesynthetic approach is discussed for the fabrication of core-shell nanostructures. The semiconducting, magnetic orsuperconducting nanoparticles are encapsulated in a carbon shell. RAPET is a one-step, thermal decomposition reaction ofchemical compound (s followed by the formation of core-shell nanoparticles in a closed stainless steel reactor. Therepresentative examples are discussed, where a variety of nanomaterials are trapped in situ in a carbon shell that offersfascinating properties.

  10. Mechanical and microstructural characterization of aluminum reinforced with carbon-coated silver nanoparticles

    International Nuclear Information System (INIS)

    Composites of pure aluminum with carbon-coated silver nanoparticles (Ag-C NP) of 10 nm in size were prepared by the mechanical milling process. Transmission electron microscopy showed that the Ag-C NP are homogeneously dispersed into the Al matrix, silver nanoparticles do not coalesce, grow or dissolve in the aluminum matrix due the carbon shell. The values of yield strength (σ y), maximum strength (σ max) and micro-hardness Vickers (HVN) of the composites were evaluated and reported as a function of Ag-C NP content. It has been found that the introduction of this type of particles in aluminum strengthen it, increasing all the previous parameters

  11. The fabrication of periodic polymer/silver nanoparticle structures: in situ reduction of silver nanoparticles from precursor spatially distributed in polymer using holographic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Smirnova, Tatiana N; Kokhtych, Lyudmila M; Sakhno, Oksana V [Institute of Physics of NAS of Ukraine, Prospekt Nauky 46, 03680 Kyiv (Ukraine); Kutsenko, Alexander S [L V Pysarzhevsky Institute of Physical Chemistry of NAS of Ukraine, Prospekt Nauky, 03039 Kyiv (Ukraine); Stumpe, Joachim [Fraunhofer Institute for Applied Polymer Research, Science Campus Golm, Geiselbergstrasse 69, D-14476 Potsdam (Germany)

    2009-10-07

    A new approach to producing volume periodic polymer-metal nanoparticle structures is presented. Periodic distribution of Ag nanoparticles in a polymer film can be obtained by applying the holographic patterning in the UV or visible spectral range to the composite material comprising photocurable monomers, photoinitiators and a solution of silver nitrate in acetonitrile. Photopolymerization of the composite in the interference pattern provides formation of a highly efficient volume grating composed of periodic polymer regions and Ag precursor-containing regions. Subsequent homogeneous UV irradiation and/or thermo-treatment of the grating causes reduction of silver ions to Ag nanoparticles in the areas of the film containing the metal precursor. Spectroscopic measurements confirm the formation of the nanoparticles in the gratings. Transmission electron microscopy showed a regular spatial distribution of well-defined Ag nanoparticles in a polymer film with a periodicity governed by the geometry of holographic structuring. The average diameter of nanoparticles can be controlled by the wavelength and intensity of holographic exposure as well as the composite formulation. A possible mechanism of silver nanoparticle formation by free radicals as reducing agents is presented.

  12. A novel nanoparticle-based disposable electrochemical immunosensor for diagnosis of exposure to toxic organophosphorus agents

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Donglai; Wang, Jun; Wang, Limin; Du, Dan; Timchalk, Charles; Barry, Richard C.; Lin, Yuehe

    2011-11-15

    We present a novel disposable electrochemical immunosensor for highly selective and sensitive detection of organophosphorylated butyrylcholinesterase (OP-BChE), a specific biomarker for exposure to toxic organophosphorus agents. In our new approach, the zirconia nanoparticles (ZrO-2) were employed to selectively capture the OP moiety of OP-BChE adducts, and followed by quantum dot (QD)-tagged anti-BChE antibodies for amplified quantification. The captured CdSe-QD tags can be sensitively detected by stripping voltammetry using in situ bismuth-plating method. The OP agent, diisopropylfluorophosphate (DFP), was selected to prepare OP-BChE adducts in various matrices. The formation of OP-BChE adducts in plasma sample was confirmed using mass spectroscopy. The developed electrochemical immunosensor demonstrates a highly linear voltammetric response over the range of 0.1 to 30 nM OP-BChE. Moreover, the immunosensor has been successfully applied for the detection of OP-BChE adducts in the plasma samples. This novel nanoparticle-based electrochemical immunosensor thus provides an alternative way for designing simple, fast, sensitive, and cost-effective sensing platform for on-site screening/evaluating exposure to a variety of OP agents.

  13. Optical visualization of individual ultralong carbon nanotubes by chemical vapour deposition of titanium dioxide nanoparticles.

    Science.gov (United States)

    Zhang, Rufan; Zhang, Yingying; Zhang, Qiang; Xie, Huanhuan; Wang, Haidong; Nie, Jingqi; Wen, Qian; Wei, Fei

    2013-01-01

    Direct visualization and manipulation of individual carbon nanotubes in ambient conditions is of great significance for their characterizations and applications. However, the observation of individual carbon nanotubes usually requires electron microscopes under high vacuum. Optical microscopes are much more convenient to be used, yet their resolution is low. Here we realize the visualization and manipulation of individual ultralong carbon nanotubes under optical microscopes by deposition of TiO2 nanoparticles on them. The strong scattering of TiO2 nanoparticles to visible light renders them visible by optical microscopes. Micro-Raman-spectroscopy measurement of individual carbon nanotubes is greatly facilitated by their optical visualization. With the assistance of TiO2 nanoparticles, individual carbon nanotubes can be easily manipulated under an optical microscope at macroscopic scale and in ambient conditions. Based on our approach, various manipulation of ultralong carbon nanotubes, including cutting, transfer, fabrication of structures/devices and pulling out inner shells of multiwalled carbon nanotubes, are demonstrated. PMID:23591894

  14. Strategy for the lowering and the assessment of exposure to nanoparticles at workspace - Case of study concerning the potential emission of nanoparticles of Lead in an epitaxy laboratory

    Science.gov (United States)

    Artous, Sébastien; Zimmermann, Eric; Douissard, Paul-Antoine; Locatelli, Dominique; Motellier, Sylvie; Derrough, Samir

    2015-05-01

    The implementation in many products of manufactured nanoparticles is growing fast and raises new questions. For this purpose, the CEA - NanoSafety Platform is developing various research topics for health and safety, environment and nanoparticles exposure in professional activities. The containment optimisation for the exposition lowering, then the exposure assessment to nanoparticles is a strategy for safety improvement at workplace and workspace. The lowering step consists in an optimisation of dynamic and static containment at workplace and/or workspace. Generally, the exposure risk due to the presence of nanoparticles substances does not allow modifying the parameters of containment at workplace and/or workspace. Therefore, gaseous or nanoparticulate tracers are used to evaluate performances of containment. Using a tracer allows to modify safely the parameters of the dynamic containment (ventilation, flow, speed) and to study several configurations of static containment. Moreover, a tracer allows simulating accidental or incidental situation. As a result, a safety procedure can be written more easily in order to manage this type of situation. The step of measurement and characterization of aerosols can therefore be used to assess the exposition at workplace and workspace. The case of study, aim of this paper, concerns the potential emission of Lead nanoparticles at the exhaust of a furnace in an epitaxy laboratory. The use of Helium tracer to evaluate the performance of containment is firstly studied. Secondly, the exposure assessment is characterised in accordance with the French guide “recommendations for characterizing potential emissions and exposure to aerosols released from nanomaterials in workplace operations”. Thirdly the aerosols are sampled, on several places, using collection membranes to try to detect traces of Lead in air.

  15. High Cycling Performance Cathode Material: Interconnected LiFePO4/Carbon Nanoparticles Fabricated by Sol-Gel Method

    OpenAIRE

    2014-01-01

    Interconnected LiFePO4/carbon nanoparticles for Li-ion battery cathode have been fabricated by sol-gel method followed by a carbon coating process involving redox reactions. The carbon layers coated on the LiFePO4 nanoparticles not only served as a protection layer but also supplied fast electrons by building a 3D conductive network. As a cooperation, LiFePO4 nanoparticles encapsulated in interconnected conductive carbon layers provided the electrode reactions with fast lithium ions by offer...

  16. Effects of titanium dioxide nanoparticle exposure in Mytilus galloprovincialis gills and digestive gland.

    Science.gov (United States)

    Gornati, Rosalba; Longo, Arturo; Rossi, Federica; Maisano, Maria; Sabatino, Giuseppe; Mauceri, Angela; Bernardini, Giovanni; Fasulo, Salvatore

    2016-08-01

    Despite the wide use of nanoscale materials in several fields, some aspects of the nanoparticle behavior have to be still investigated. In this work, we faced the aspect of environmental effects of increasing concentrations of TiO2NPs using the Mytilus galloprovincialis as an animal model and carrying out a multidisciplinary approach to better explain the results. Bioaccumulation suggested that the gills and digestive gland are the most sensitive organs to TiO2NP exposure. Histological observations have evidenced an altered tissue organization and a consistent infiltration of hemocytes, as a consequence of the immune system activation, even though an increase in lipid peroxidation is uncertain and DNA damage became relevant only at high exposure dose (10 mg/L) or for longer exposure time (96 h). However, the over expression of SOD1 mRNA strengthen the concept that the toxicity of TiO2NPs could occur indirectly by ROS production. TEM analysis showed the presence of multilamellar bodies, RER fragmentation, and cytoplasmic vacuolization within relevant presence of dense granules, residual bodies, and lipid inclusions. These findings support the evidence of an initial inflammatory response by the cells of the target organs leading to apoptosis. In conclusion, we can state that certainly the exposure to TiO2NPs has affected our animal model from cellular to molecular levels. Interestingly, the same responses are caused by lower TiO2NP concentration and longer exposure time as well as higher doses and shorter exposure. We do not know if some of the conditions detected are reversible, then further studies are required to clarify this aspect. PMID:26846715

  17. Physical and anti-microbial characteristics of carbon nanoparticles prepared from lamp soot

    International Nuclear Information System (INIS)

    Soot originating from the burning of butter and mustard oil in a lamp with a cotton wick was collected on a brass plate and dispersed in water and carbon tetrachloride (CCl4) as naked, and as Gum Arabic (GA, a anionic polyelectrolyte)-coated nanoparticles in water. They were physically characterized, and their anti-bacterial activities were probed on gram positive and negative bacterial colonies. TEM data revealed the presence of 35-55 nm diameter spherical carbon nanoparticles in water and CCl4. The dynamic light scattering determined the average hydrodynamic diameter for the same samples, which was found to be ∼100 nm (in CCl4) and ∼240 nm (in water), implying the packing of these nanoparticles into clusters. GA-coated particles yielded stable suspensions in water, but the clusters were almost the same in size (∼250 nm). The zeta potential distributions of the naked and the GA-coated nanoparticles were found to be unimodal and bimodal, respectively, with both yielding mean zeta potential values nearly equal to zero. Results of energy-dispersive x-ray analysis (EDAX) confirmed the absence of toxic metallic elements inside the specimen. X-ray diffraction study confirmed the presence of amorphous as well as graphitized carbon in these nanostructures. The anti-microbial activities in terms of growth inhibition for the carbon nanoparticles against Staphylococcus aureus, ATCC 13709 (native strain) and Klebsiella pneumonia ATCC 29655 (native strain) were assayed in agar gel. In vitro testing revealed significant anti-microbial activity against Klebsiella pneumonia, but carbon nanoparticles were unable to kill Staphylococcus aureus

  18. Physical and anti-microbial characteristics of carbon nanoparticles prepared from lamp soot

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, B [Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067 (India); Verma, Anita K [Nano-Biotech Laboratory, Department of Zoology, K M College, University of Delhi, Delhi-110007 (India); Claesson, P [Department of Chemistry, Surface Chemistry, Royal Institute of Technology, Drottning Kristinas Vaeg 51, Stockholm, SE-10044 (Sweden); Bohidar, H B [Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067 (India)

    2007-11-07

    Soot originating from the burning of butter and mustard oil in a lamp with a cotton wick was collected on a brass plate and dispersed in water and carbon tetrachloride (CCl{sub 4}) as naked, and as Gum Arabic (GA, a anionic polyelectrolyte)-coated nanoparticles in water. They were physically characterized, and their anti-bacterial activities were probed on gram positive and negative bacterial colonies. TEM data revealed the presence of 35-55 nm diameter spherical carbon nanoparticles in water and CCl{sub 4}. The dynamic light scattering determined the average hydrodynamic diameter for the same samples, which was found to be {approx}100 nm (in CCl{sub 4}) and {approx}240 nm (in water), implying the packing of these nanoparticles into clusters. GA-coated particles yielded stable suspensions in water, but the clusters were almost the same in size ({approx}250 nm). The zeta potential distributions of the naked and the GA-coated nanoparticles were found to be unimodal and bimodal, respectively, with both yielding mean zeta potential values nearly equal to zero. Results of energy-dispersive x-ray analysis (EDAX) confirmed the absence of toxic metallic elements inside the specimen. X-ray diffraction study confirmed the presence of amorphous as well as graphitized carbon in these nanostructures. The anti-microbial activities in terms of growth inhibition for the carbon nanoparticles against Staphylococcus aureus, ATCC 13709 (native strain) and Klebsiella pneumonia ATCC 29655 (native strain) were assayed in agar gel. In vitro testing revealed significant anti-microbial activity against Klebsiella pneumonia, but carbon nanoparticles were unable to kill Staphylococcus aureus.

  19. 75 FR 80819 - Draft Current Intelligence Bulletin “Occupational Exposure to Carbon Nanotubes and Nanofibers”

    Science.gov (United States)

    2010-12-23

    ... HUMAN SERVICES Centers for Disease Control and Prevention Draft Current Intelligence Bulletin... risks. A draft Current Intelligence Bulletin entitled ``Occupational Exposure to Carbon Nanotubes and..., telephone number, and relevant business affiliations of the presenter, topic of the presentation, and ]...

  20. Template directed formation of nanoparticle decorated multi-walled carbon nanotube bundles with uniform diameter

    International Nuclear Information System (INIS)

    Bundles of multi-walled carbon nanotubes of uniform diameter decorated with Ni nanoparticles were synthesized using mesoporous silicates as templates. The ordered morphology and the narrow pore size distribution of mesoporous silicates provide an ideal platform to synthesize uniformly sized carbon nanotubes. In addition, homogeneous sub-10 nm pore sizes of the templates allow in situ formation of catalytic nanoparticles with uniform diameters which end up decorating the carbon nanotubes. The resulting carbon nanotubes are multi-walled with a uniform diameter corresponding to the pore diameter of the template used during the synthesis that are decorated with the catalysts used to synthesize them. They have a narrow size distribution which can be used in many energy related fields of research.

  1. Establishment of Airborne Nanoparticle Exposure Chamber System to Assess Nano TiO2 Induced Mice Lung Effects

    Science.gov (United States)

    Chen, Chia-Hua; Li, Jui-Ping; Huang, Nai-Chun; Yang, Chung-Shi; Chen, Jen-Kun

    2011-12-01

    A great many governments have schemed their top priority to support the research and development of emerging nanotechnology, which lead to increasing products containing nanomaterials. However, platforms and protocols to evaluate the safety of nanomaterials are not yet established. We therefore design and fabricate a nanoparticle exposure chamber system (NECS) and try to standardize protocols to assess potential health risk of inhalable nanoparticles. This platform comprises: (1) nano-aerosol generators to produce homogeneous airborne nanoparticles, (2) double isolated container to prevent from unexpected exposure to humans, (3) gas supply system for housing animals or incubating cultured cells, and (4) system for automatic control and airborne nanoparticle analysis. The NECS providing multiple functions includes: (1) a secure environment to handle nanomaterials, (2) real-time measurement for the size and distribution of airborne nanoparticles, (3) SOP of safety evaluation for nanomaterials, and (4) key technology for the development of inhalable pharmaceuticals. We used NECS to mimic occupational environment for exploring potential adverse effects of TiO2 nanoparticles. The adult male ICR mice were exposed to 25nm, well-characterized TiO2 particles for 1 and 4 weeks. More than 90% of the inhaled TiO2 nanoparticles deposit in lung tissue, which tends to be captured by alveolar macrophages. Pulmonary function test does not show significant physiological changes between one and 4 weeks exposure. For plasma biochemistry analysis, there are no obvious inflammation responses after exposure for one and 4 weeks; however, disruption of alveolar septa and increased thickness of alveolar epithelial cells were observed. According to our results, the NECS together with our protocols show comprehensive integration and ideally fit the standard of OECD guildelines-TG403, TG412, TG413; it can be further customized to fulfill diverse demands of industry, government, and third party

  2. Palladium nanoparticles on hierarchical carbon surfaces: A new architecture for robust nano-catalysts

    Science.gov (United States)

    Vijwani, Hema; Mukhopadhyay, Sharmila M.

    2012-12-01

    Surface activity of heterogeneous catalysts can be enhanced if their sizes are reduced to nanometers. However, loose nanomaterials pose potential health and environmental risks. This issue has been addressed by attachment of palladium nanoparticles on multi-scale hierarchical carbon supports that have exceptionally high surface area per volume. The supports consist of porous carbon foam whose surface has been either chemically functionalized, or morphologically altered by grafting of carbon-nanotubes. It is seen that whereas chemical functionalization does provide some increase in nano-catalyst loading, morphological modification is significantly more powerful. It has the potential to create orders of magnitude increase in catalytic activity within the same overall volume. The synthesis techniques have been investigated in sufficient detail to provide significant control over the density and size of nanoparticles. Abundant distribution of nanoparticles is observed even within the deeper pores of the microcellular foam. The nanoparticles are seen to be metallic Pd having face centered cubic structure. Additionally, the nano-particles and nanotubes are durable, and remain attached to the base support after long periods of rapid rotation in water. These robust hybrid structures show promise in future applications such as sensors, water purification systems, fuel cell electrodes and hydrogen storage sponges.

  3. Arc-Discharge Synthesis of Iron Encapsulated in Carbon Nanoparticles for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    S. Chaitoglou

    2014-01-01

    Full Text Available The objective of the present work is to improve the protection against the oxidation that usually appears in core@shell nanoparticles. Spherical iron nanoparticles coated with a carbon shell were obtained by a modified arc-discharge reactor, which permits controlling the diameter of the iron core and the carbon shell of the particles. Oxidized iron nanoparticles involve a loss of the magnetic characteristics and also changes in the chemical properties. Our nanoparticles show superparamagnetic behavior and high magnetic saturation owing to the high purity α-Fe of core and to the high core sealing, provided by the carbon shell. A liquid iron precursor was injected in the plasma spot dragged by an inert gas flow. A fixed arc-discharge current of 40 A was used to secure a stable discharge, and several samples were produced at different conditions. Transmission electron microscopy indicated an iron core diameter between 5 and 9 nm. Selected area electron diffraction provided evidences of a highly crystalline and dense iron core. The magnetic properties were studied up to 5 K temperature using a superconducting quantum interference device. The results reveal a superparamagnetic behaviour, a narrow size distribution (σg=1.22, and an average diameter of 6 nm for nanoparticles having a blocking temperature near 40 K.

  4. Gold nanoparticles directly modified glassy carbon electrode for non-enzymatic detection of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Gang; Shu, Honghui; Ji, Kai [Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Faculty of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); Oyama, Munetaka [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8520 (Japan); Liu, Xiong [Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Faculty of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); He, Yunbin, E-mail: ybhe@hubu.edu.cn [Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Faculty of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China)

    2014-01-01

    This work describes controllable preparation of gold nanoparticles on glassy carbon electrodes by using the seed mediated growth method, which contains two steps, namely, nanoseeds attachment and nanocrystals growth. The size and the dispersion of gold nanoparticles grown on glassy carbon electrodes could be easily tuned through the growth time based on results of field-emission scanning electron microscopy. Excellent electrochemical catalytic characteristics for glucose oxidation were observed for the gold nanoparticles modified glassy carbon electrodes (AuNPs/GC), resulting from the extended active surface area provided by the dense gold nanoparticles attached. It exhibited a wide linear range from 0.1 mM to 25 mM with the sensitivity of 87.5 μA cm{sup −2} mM{sup −1} and low detection limit down to 0.05 mM for the sensing of glucose. The common interfering species such as chloride ion, ascorbic acid, uric acid and 4-acetamidophenol were verified having no interference effect on the detection of glucose. It is demonstrated that the seed mediated method is one of the facile approaches for fabricating Au nanoparticles modified substrates, which could work as one kind of promising electrode materials for the glucose nonenzymatic sensing.

  5. Natural reducing agents for electroless nanoparticle deposition: Mild synthesis of metal/carbon nanostructured microspheres

    International Nuclear Information System (INIS)

    Composite materials are of interest because they can potentially combine the properties of their respective components in a manner that is useful for specific applications. Here, we report on the use of coffee as a low-cost, green reductant for the room temperature formation of catalytically active, supported metal nanoparticles. Specifically, we have leveraged the reduction potential of coffee in order to grow Pd and Ag nanoparticles at the surface of porous carbon microspheres synthesized via ultraspray pyrolysis. The metal nanoparticle-on-carbon microsphere composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). To demonstrate the catalytic activity of Pd/C and Ag/C materials, Suzuki coupling reactions and nitroaromatic reduction reactions were employed, respectively. - Highlights: • Natural reductants were used as green electroless deposition reagents. • Room temperature synthesis of supported Ag and Pd nanoparticles was achieved. • Carbon porous microspheres were used as supports. • Synthesis via natural reductants yielded catalytically active nanoparticles.

  6. Comparative analysis of the secondary electron yield from carbon nanoparticles and pure water medium

    International Nuclear Information System (INIS)

    The issue of enhancing the radiosensitivity of tumors is important in radiotherapy. The production of secondary electrons generated by carbon nanoparticles and pure water medium irradiated by fast protons is studied by means of model approaches and Monte Carlo simulations. It is demonstrated that due to a prominent collective response to an external field, the nanoparticles embedded in the medium enhance the yield of low-energy electrons. The maximal enhancement is observed for electrons in the energy range where plasmons, which are excited in the nanoparticles, play the dominant role. The electron yield from a solid carbon nanoparticle composed of fullerite, a crystalline form of C60 fullerene, is demonstrated to be several times higher than that from liquid water. Decay of plasmon excitations in carbon-based nano-systems thus represents a mechanism of increasing the low-energy electron yield, similar to the case of sensitizing metal nanoparticles. This observation gives a hint for investigation of novel types of sensitizers to be composed of metallic and organic parts. (authors)

  7. Natural reducing agents for electroless nanoparticle deposition: Mild synthesis of metal/carbon nanostructured microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, Paul [School of Chemistry, University of Dublin Trinity College, College Green, Dublin 2 (Ireland); Reynolds, Lyndsey A.; Sanders, Stephanie E. [Department of Chemistry, Albion College, 611 E. Porter St., Albion, MI 49224 (United States); Metz, Kevin M., E-mail: kmetz@albion.edu [Department of Chemistry, Albion College, 611 E. Porter St., Albion, MI 49224 (United States); Colavita, Paula E., E-mail: colavitp@tcd.ie [School of Chemistry, University of Dublin Trinity College, College Green, Dublin 2 (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)

    2013-06-15

    Composite materials are of interest because they can potentially combine the properties of their respective components in a manner that is useful for specific applications. Here, we report on the use of coffee as a low-cost, green reductant for the room temperature formation of catalytically active, supported metal nanoparticles. Specifically, we have leveraged the reduction potential of coffee in order to grow Pd and Ag nanoparticles at the surface of porous carbon microspheres synthesized via ultraspray pyrolysis. The metal nanoparticle-on-carbon microsphere composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). To demonstrate the catalytic activity of Pd/C and Ag/C materials, Suzuki coupling reactions and nitroaromatic reduction reactions were employed, respectively. - Highlights: • Natural reductants were used as green electroless deposition reagents. • Room temperature synthesis of supported Ag and Pd nanoparticles was achieved. • Carbon porous microspheres were used as supports. • Synthesis via natural reductants yielded catalytically active nanoparticles.

  8. Evaluation of silica nanoparticle toxicity after topical exposure for 90 days

    Directory of Open Access Journals (Sweden)

    Ryu HJ

    2014-12-01

    Full Text Available Hwa Jung Ryu,1,* Nak-won Seong,2,* Byoung Joon So,1 Heung-sik Seo,2 Jun-ho Kim,2 Jeong-Sup Hong,2 Myeong-kyu Park,2 Min-Seok Kim,2 Yu-Ri Kim,3 Kyu-Bong Cho,4 Mu yeb Seo,2 Meyoung-Kon Kim,3 Eun Ho Maeng,2 Sang Wook Son1 1Department of Dermatology, Korea University College of Medicine, Seoul, South Korea; 2Korea Testing and Research Institute, Gyunggi-Do, South Korea; 3Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul, South Korea; 4Department of Clinical Laboratory Science, Shinheung College, Uijeongbu, South Korea *These authors contributed equally to this work Abstract: Silica is a very common material that can be found in both crystalline and amorphous forms. Well-known toxicities of the lung can occur after exposure to the crystalline form of silica. However, the toxicities of the amorphous form of silica have not been thoroughly studied. The majority of in vivo studies of amorphous silica nanoparticles (NPs were performed using an inhalation exposure method. Since silica NPs can be commonly administered through the skin, a study of dermal silica toxicity was necessary to determine any harmful effects from dermal exposures. The present study focused on the results of systemic toxicity after applying 20 nm colloidal silica NPs on rat skin for 90 days, in accordance with the Organization for Economic Cooperation and Development test guideline 411 with a good laboratory practice system. Unlike the inhalation route or gastrointestinal route, the contact of silica NPs through skin did not result in any toxicity or any change in internal organs up to a dose of 2,000 mg/kg in rats. Keywords: silica nanoparticles, toxicity, dermal route

  9. Synthesis of carbon-supported PtRh random alloy nanoparticles using electron beam irradiation reduction method

    Science.gov (United States)

    Matsuura, Yoshiyuki; Seino, Satoshi; Okazaki, Tomohisa; Akita, Tomoki; Nakagawa, Takashi; Yamamoto, Takao A.

    2016-05-01

    Bimetallic nanoparticle catalysts of PtRh supported on carbon were synthesized using an electron beam irradiation reduction method. The PtRh nanoparticle catalysts were composed of particles 2-3 nm in size, which were well dispersed on the surface of the carbon support nanoparticles. Analyses of X-ray diffraction and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy revealed that the PtRh nanoparticles have a randomly alloyed structure. The lattice constant of the PtRh nanoparticles showed good correlation with Vegard's law. These results are explained by the radiochemical formation process of the PtRh nanoparticles. Catalytic activities of PtRh/C nanoparticles for ethanol oxidation reaction were found to be higher than those obtained with Pt/C.

  10. Effects of Acute Exposures to Carbon Dioxide Upon Cognitive Functions

    Science.gov (United States)

    Scully, R. R.; Alexander, D. J.; Ryder, V. E.; Lam, C. W.; Statish, U.; Basner, M.

    2016-01-01

    Large quantities of carbon dioxide (CO2) originate from human metabolism and typically, within spacecraft, remain about 10-fold higher in concentration than at the earth's surface. There have been recurring complaints by crew members of episodes of "mental viscosity" adversely affecting their performance, and there is evidence from the International Space Station (ISS) that associates CO2 levels with reports of headaches by crewmembers. Additionally, there is concern that CO2 may contribute to vision impairment and intracranial pressure that has been observed in some crewmembers. Consequently, flight rules have been employed to control the level of CO2 below 4 mm Hg, which is well below the existing Spacecraft Maximum Allowable Concentration (SMAC) of 10 mm Hg for 24-hour exposures, and 5.3 mm Hg for exposures of 7 to 180 days. However, the flight rule imposed limit, which places additional demands upon resources and current technology, still exceeds the lower bound of the threshold range for reportable headaches (2 - 5 mm Hg). Headaches, while sometime debilitating themselves, are also symptoms that can provide evidence that physiological defense mechanisms have been breached. The causes of the headaches may elicit other subtle adverse effects that occur at CO2 levels well below that for headaches. The concern that CO2 may have effects at levels below the threshold for headaches appears to be substantiated in unexpected findings that CO2 at concentrations below 2 mm Hg substantially reduced some cognitive functions that are associated with the ability to make complex decisions in conditions that are characterized by volatility, uncertainty, complexity, ambiguity, and delayed feedback. These are conditions that could be encountered by crews in off-nominal situations or during the first missions beyond low earth orbit. If findings of the earlier study are confirmed in crew-like subjects, our findings would provide additional evidence that CO2 may need to be

  11. Development of a carbon-nanoparticle-coated stirrer for stir bar sorptive extraction by a simple carbon deposition in flame.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-03-01

    Stir bar sorptive extraction is an environmentally friendly microextraction technique based on a stir bar with various sorbents. A commercial stirrer is a good support, but it has not been used in stir bar sorptive extraction due to difficult modification. A stirrer was modified with carbon nanoparticles by a simple carbon deposition process in flame and characterized by scanning electron microscopy and energy-dispersive X-ray spectrometry. A three-dimensional porous coating was formed with carbon nanoparticles. In combination with high-performance liquid chromatography, the stir bar was evaluated using five polycyclic aromatic hydrocarbons as model analytes. Conditions including extraction time and temperature, ionic strength, and desorption solvent were investigated by a factor-by-factor optimization method. The established method exhibited good linearity (0.01-10 μg/L) and low limits of quantification (0.01 μg/L). It was applied to detect model analytes in environmental water samples. No analyte was detected in river water, and five analytes were quantified in rain water. The recoveries of five analytes in two samples with spiked at 2 μg/L were in the range of 92.2-106% and 93.4-108%, respectively. The results indicated that the carbon nanoparticle-coated stirrer was an efficient stir bar for extraction analysis of some polycyclic aromatic hydrocarbons. PMID:26663510

  12. Nanoparticle Traffic on Helical Tracks: Thermophoretic Mass Transport through Carbon Nanotubes

    DEFF Research Database (Denmark)

    Schoen, Philipp A.E.; Walther, Jens Honore; Arcidiacono, Salvatore; Poulikakos, Dimos; Koumoutsakos, Petros

    2006-01-01

    Using molecular dynamics simulations, we demonstrate and quantify thermophoretic motion of solid gold nanoparticles inside carbon nanotubes subject to wall temperature gradients ranging from 0.4 to 25 K/nm. For temperature gradients below 1 K/nm, we find that the particles move "on tracks" in a...... predictable fashion as they follow unique helical orbits depending on the geometry of the carbon nanotubes. These findings markedly advance our knowledge of mass transport mechanisms relevant to nanoscale applications....

  13. Monodisperse Mesoporous Carbon Nanoparticles from Polymer/Silica Self-Aggregates and Their Electrocatalytic Activities.

    Science.gov (United States)

    Huang, Xiaoxi; Zhou, Li-Jing; Voiry, Damien; Chhowalla, Manish; Zou, Xiaoxin; Asefa, Tewodros

    2016-07-27

    In our quest to make various chemical processes sustainable, the development of facile synthetic routes and inexpensive catalysts can play a central role. Herein we report the synthesis of monodisperse, polyaniline (PANI)-derived mesoporous carbon nanoparticles (PAMCs) that can serve as efficient metal-free electrocatalysts for the hydrogen peroxide reduction reaction (HPRR) as well as the oxygen reduction reaction (ORR) in fuel cells. The materials are synthesized by polymerization of aniline with the aid of (NH4)2S2O8 as oxidant and colloidal silica nanoparticles as templates, then carbonization of the resulting PANI/silica composite material at different high temperatures, and finally removal of the silica templates from the carbonized products. The PAMC materials that are synthesized under optimized synthetic conditions possess monodisperse mesoporous carbon nanoparticles with an average size of 128 ± 12 nm and an average pore size of ca. 12 nm. Compared with Co3O4, a commonly used electrocatalyst for HPRR, these materials show much better catalytic activity for this reaction. In addition, unlike Co3O4, the PAMCs remain relatively stable during the reaction, under both basic and acidic conditions. The nanoparticles also show good electrocatalytic activity toward ORR. Based on the experimental results, PAMCs' excellent electrocatalytic activity is attributed partly to their heteroatom dopants and/or intrinsic defect sites created by vacancies in their structures and partly to their high porosity and surface area. The reported synthetic method is equally applicable to other polymeric precursors (e.g., polypyrrole (PPY)), which also produces monodisperse, mesoporous carbon nanoparticles in the same way. The resulting materials are potentially useful not only for electrocatalysis of HPRR and ORR in fuel cells but also for other applications where high surface area, small sized, nanostructured carbon materials are generally useful for (e.g., adsorption

  14. Exposure to Inhaled Nickel Nanoparticles Causes a Reduction in Number and Function of Bone Marrow Endothelial Progenitor Cells

    Science.gov (United States)

    Liberda, Eric N; Cuevas, Azita K; Gillespie, Patricia A; Grunig, Gabriele; Qu, Qingshan; Chen, Lung Chi

    2016-01-01

    Introduction Particulate matter (PM), specifically nickel (Ni) found on or in PM, has been associated with an increased risk of mortality in human population studies and significant increases in vascular inflammation, generation of reactive oxygen species, altered vasomotor tone, and potentiated atherosclerosis in murine exposures. Recently, murine inhalation of Ni nanoparticles have been shown to cause pulmonary inflammation which affects cardiovascular tissue and potentiates atherosclerosis. These adverse cardiovascular outcomes may be due to the effects of Ni on endothelial progenitor cells (EPCs), endogenous semi-pluripotent stem cells that aid in endothelial repair. Thus, we hypothesize that Ni nanoparticle exposures decrease cell count and cause impairments in function which may ultimately have significant effects on various cardiovascular diseases such as atherosclerosis. Methods Experiments involving inhaled Ni nanoparticle exposures(2 days/5 hrs/day at ~1000 μg/m3, 3 days/5 hrs/day at ~1000 μg/m3, and 5days/5 hrs/day at ~100 μg/m3), were performed in order to quantify bone marrow resident EPCs using flow cytometry in C57BL/6 mice. Plasma levels of SDF-1α and VEGF were assessed by ELISA and in vitro functional assessments of cultured EPCs were conducted. Results and Conclusions Significant EPC count differences between exposure and control groups for Ni nanoparticle exposures were observed. Differences in EPC tube formation and chemotaxis were also observed for the Ni nanoparticle exposed group. Plasma VEGF and SDF-1α differences were not statistically significant. In conclusion, this study shows that inhalation of Ni nanoparticles results in functionally impaired EPCs and reduced number in the bone marrow, which may lead to enhanced progression of atherosclerosis. PMID:20936915

  15. Investigation of superparamagnetic (Fe3O4) nanoparticles and magnetic field exposures on CHO-K1 cell line

    Science.gov (United States)

    Coker, Zachary; Estlack, Larry; Hussain, Saber; Choi, Tae-Youl; Ibey, Bennett L.

    2016-03-01

    Rapid development in nanomaterial synthesis and functionalization has led to advanced studies in actuation and manipulation of cellular functions for biomedical applications. Often these actuation techniques employ externally applied magnetic fields to manipulate magnetic nanomaterials inside cell bodies in order to drive or trigger desired effects. While cellular interactions with low-frequency magnetic fields and nanoparticles have been extensively studied, the fundamental mechanisms behind these interactions remain poorly understood. Additionally, modern investigations on these concurrent exposure conditions have been limited in scope, and difficult to reproduce. This study presents an easily reproducible method of investigating the biological impact of concurrent magnetic field and nanoparticle exposure conditions using an in-vitro CHO-K1 cell line model, with the purpose of establishing grounds for in-depth fundamental studies of the mechanisms driving cellular-level interactions. Cells were cultured under various nanoparticle and magnetic field exposure conditions from 0 to 500 μg/ml nanoparticle concentrations, and DC, 50 Hz, or 100 Hz magnetic fields with 2.0 mT flux density. Cells were then observed by confocal fluorescence microscopy, and subject to biological assays to determine the effects of concurrent extreme-low frequency magnetic field and nanoparticle exposures on cellnanoparticle interactions, such as particle uptake and cell viability by MTT assay. Current results indicate little to no variation in effect on cell cultures based on magnetic field parameters alone; however, it is clear that deleterious synergistic effects of concurrent exposure conditions exist based on a significant decrease in cell viability when exposed to high concentrations of nanoparticles and concurrent magnetic field.

  16. Exposure of pregnant mice to carbon black by intratracheal instillation

    DEFF Research Database (Denmark)

    Jackson, Petra; Hougaard, Karin S.; Vogel, Ulla;

    2011-01-01

    Exposure to nanomaterials (NM) during sensitive developmental stages may predispose organisms to diseases later in life. However, direct translocation of NM from mother to fetus through the placenta is limited. The present study tests the hypothesis that pulmonary exposure to NM and NM-induced re...

  17. Silver Nanoparticles and Graphitic Carbon Through Thermal Decomposition of a Silver/Acetylenedicarboxylic Salt

    Directory of Open Access Journals (Sweden)

    Komninou Philomela

    2009-01-01

    Full Text Available Abstract Spherically shaped silver nanoparticles embedded in a carbon matrix were synthesized by thermal decomposition of a Ag(I/acetylenedicarboxylic acid salt. The silver nanoparticles, which are formed either by pyrolysis at 300 °C in an autoclave or thermolysis in xylene suspension at reflux temperature, are acting catalytically for the formation of graphite layers. Both reactions proceed through in situ reduction of the silver cations and polymerization of the central acetylene triple bonds and the exact temperature of the reaction can be monitored through DTA analysis. Interestingly, the thermal decomposition of this silver salt in xylene partly leads to a minor fraction of quasicrystalline silver, as established by HR-TEM analysis. The graphitic layers covering the silver nanoparticles are clearly seen in HR-TEM images and, furthermore, established by the presence of sp2carbon at the Raman spectrum of both samples.

  18. Synthesis and characterization of platinum nanoparticles on single-walled Carbon nanotube 'nanopaper' support

    International Nuclear Information System (INIS)

    We prepared several samples of carbon-nanotube-supported Pt nanoparticles that are potentially promising electrocatalysts for hydrogen fuel cells. Commercially obtained single-walled carbon nanotubes (SWNTs) were characterized by Raman Spectroscopy, SEM, TEM, EDS, and XANES. This multi-technique characterization allowed us to quantify the size and composition of metal impurities (Mo, Co) in SWNTs, to choose the best method to remove them, and characterize the effectiveness of their removal. After synthesizing a 'nanopaper' (10-20 micrometer thick, free standing sheets of self-assembled SWNTs) we decorated it with Pt nanoparticles by electroless deposition. Formation of Pt nanoparticles was verified by EXAFS, and quantitative information about their size and structure was obtained.

  19. Simultaneous voltammetric determination of tramadol and acetaminophen using carbon nanoparticles modified glassy carbon electrode

    International Nuclear Information System (INIS)

    A sensitive and selective electrochemical sensor was fabricated via the drop-casting of carbon nanoparticles (CNPs) suspension onto a glassy carbon electrode (GCE). The application of this sensor was investigated in simultaneous determination of acetaminophen (ACE) and tramadol (TRA) drugs in pharmaceutical dosage form and ACE determination in human plasma. In order to study the electrochemical behaviors of the drugs, cyclic and differential pulse voltammetric studies of ACE and TRA were carried out at the surfaces of the modified GCE (MGCE) and the bare GCE. The dependence of peak currents and potentials on pH, concentration and the potential scan rate were investigated for these compounds at the surface of MGCE. Atomic force microscopy (AFM) was used for the characterization of the film modifier and its morphology on the surface of GCE. The results of the electrochemical investigations showed that CNPs, via a thin layer model based on the diffusion within a porous layer, enhanced the electroactive surface area and caused a remarkable increase in the peak currents. The thin layer of the modifier showed a catalytic effect and accelerated the rate of the electron transfer process. Application of the MGCE resulted in a sensitivity enhancement and a considerable decrease in the anodic overpotential, leading to negative shifts in peak potentials. An optimum electrochemical response was obtained for the sensor in the buffered solution of pH 7.0 and using 2 μL CNPs suspension cast on the surface of GCE. Using differential pulse voltammetry, the prepared sensor showed good sensitivity and selectivity for the determination of ACE and TRA in wide linear ranges of 0.1-100 and 10-1000 μM, respectively. The resulted detection limits for ACE and TRA was 0.05 and 1 μM, respectively. The CNPs modified GCE was successfully applied for ACE and TRA determinations in pharmaceutical dosage forms and also for the determination of ACE in human plasma.

  20. Simultaneous voltammetric determination of tramadol and acetaminophen using carbon nanoparticles modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani-Bidkorbeh, Fatemeh [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahrokhian, Saeed, E-mail: shahrokhian@sharif.ed [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Institute for Nanoscience and Technology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mohammadi, Ali [Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Dinarvand, Rassoul [Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran (Iran, Islamic Republic of)

    2010-03-01

    A sensitive and selective electrochemical sensor was fabricated via the drop-casting of carbon nanoparticles (CNPs) suspension onto a glassy carbon electrode (GCE). The application of this sensor was investigated in simultaneous determination of acetaminophen (ACE) and tramadol (TRA) drugs in pharmaceutical dosage form and ACE determination in human plasma. In order to study the electrochemical behaviors of the drugs, cyclic and differential pulse voltammetric studies of ACE and TRA were carried out at the surfaces of the modified GCE (MGCE) and the bare GCE. The dependence of peak currents and potentials on pH, concentration and the potential scan rate were investigated for these compounds at the surface of MGCE. Atomic force microscopy (AFM) was used for the characterization of the film modifier and its morphology on the surface of GCE. The results of the electrochemical investigations showed that CNPs, via a thin layer model based on the diffusion within a porous layer, enhanced the electroactive surface area and caused a remarkable increase in the peak currents. The thin layer of the modifier showed a catalytic effect and accelerated the rate of the electron transfer process. Application of the MGCE resulted in a sensitivity enhancement and a considerable decrease in the anodic overpotential, leading to negative shifts in peak potentials. An optimum electrochemical response was obtained for the sensor in the buffered solution of pH 7.0 and using 2 muL CNPs suspension cast on the surface of GCE. Using differential pulse voltammetry, the prepared sensor showed good sensitivity and selectivity for the determination of ACE and TRA in wide linear ranges of 0.1-100 and 10-1000 muM, respectively. The resulted detection limits for ACE and TRA was 0.05 and 1 muM, respectively. The CNPs modified GCE was successfully applied for ACE and TRA determinations in pharmaceutical dosage forms and also for the determination of ACE in human plasma.

  1. nanoparticles

    Science.gov (United States)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  2. Carbon nanotube anions for the preparation of gold nanoparticle-nanocarbon hybrids.

    Science.gov (United States)

    Bayazit, Mustafa K; Hodge, Stephen A; Clancy, Adam J; Menzel, Robert; Chen, Shu; Shaffer, Milo S P

    2016-01-31

    Gold nanoparticles (AuNPs) can be evenly deposited on single-walled carbon nanotubes (SWCNTs) via the reduction of the highly stable complex, chloro(triphenylphosphine) gold(I), with SWCNT anions ('nanotubides'). This methodology highlights the unusual chemistry of nanotubides and provides a blueprint for the generation of many other hybrid nanomaterials. PMID:26679693

  3. A transparent hybrid of nanocrystalline cellulose and amorphous calcium carbonate nanoparticles

    OpenAIRE

    Gebauer, Denis; Oliynyk, Vitaliy; Salajkova, Michaela; Sort, Jordi; Zhou, Qi; Bergström, Lennart; Salazar-Alvarez, German

    2011-01-01

    Nanocellulose hybrids are promising candidates for biodegradable multifunctional materials. Hybrids of nanocrystalline cellulose (NCC) and amorphous calcium carbonate (ACC) nanoparticles were obtained through a facile chemical approach over a wide range of compositions. Controlling the interactions between NCC and ACC results in hard, transparent structures with tunable composition, homogeneity and anisotropy.

  4. Highly Luminescent Carbon-​Nanoparticle-​Based Materials: Factors Influencing Photoluminescence Quantum Yield

    NARCIS (Netherlands)

    S. Qu; D. Shen; X. Liu; P. Jing; L. Zhang; W. Ji; H. Zhao; X. Fan; H. Zhang

    2014-01-01

    Unravelling the factors influencing photoluminescence (PL) quantum yield of the carbon nanoparticles (CNPs) is the prerequisite for prepg. highly luminescent CNP-​based materials. In this work, an easy and effective method is reported for prepg. highly luminescent CNP-​based materials. Water-​sol. l

  5. Fabrication of Carbon Nanotube/SiO2and Carbon Nanotube/SiO2/Ag Nanoparticles Hybrids by Using Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Li Haiqing

    2009-01-01

    Full Text Available Abstract Based on plasma-treated single wall carbon nanotubes (SWCNTs, SWCNT/SiO2and thiol groups-functionalized SWCNT/SiO2hybrids have been fabricated through a sol–gel process. By means of thiol groups, Ag nanoparticles have been in situ synthesized and bonded onto the SiO2shell of SWCNT/SiO2in the absence of external reducing agent, resulting in the stable carbon nanotube/SiO2/Ag nanoparticles hybrids. This strategy provides a facile, low–cost, and green methodology for the creation of carbon nanotube/inorganic oxides-metal nanoparticles hybrids.

  6. Exposure limits for nanoparticles: report of an international workshop on nano reference values.

    Science.gov (United States)

    van Broekhuizen, Pieter; van Veelen, Wim; Streekstra, Willem-Henk; Schulte, Paul; Reijnders, Lucas

    2012-07-01

    This article summarizes the outcome of the discussions at the international workshop on nano reference values (NRVs), which was organized by the Dutch trade unions and employers' organizations and hosted by the Social Economic Council in The Hague in September 2011. It reflects the discussions of 80 international participants representing small- and medium-size enterprises (SMEs), large companies, trade unions, governmental authorities, research institutions, and non-governmental organizations (NGOs) from many European countries, USA, India, and Brazil. Issues that were discussed concerned the usefulness and acceptability of precaution-based NRVs as a substitute for health-based occupational exposure limits (OELs) and derived no-effect levels (DNELs) for manufactured nanoparticles (NPs). Topics concerned the metrics for measuring NPs, the combined exposure to manufactured nanomaterials (MNMs) and process-generated NPs, the use of the precautionary principle, the lack of information about the presence of nanomaterials, and the appropriateness of soft regulation for exposure control. The workshop concluded that the NRV, as an 8-h time-weighted average, is a comprehensible and useful instrument for risk management of professional use of MNMs with a dispersible character. The question remains whether NRVs, as advised for risk management by the Dutch employers' organization and trade unions, should be under soft regulation or that a more binding regulation is preferable. PMID:22752096

  7. Cytotoxicity and inflammation in human alveolar epithelial cells following exposure to occupational levels of gold and silver nanoparticles

    International Nuclear Information System (INIS)

    While inhalation represents one of the most likely routes of exposure, the toxicity and response of nanoparticles at concentrations expected from such an exposure are not well understood. Here we characterized the in vitro response of human A549 adenocarcinomic alveolar epithelial cells following exposure to gold (AuNP) and silver (AgNP) nanoparticles at levels approximating an occupational exposure. Changes in neither oxidative stress nor cytotoxicity were significantly affected by exposure to AgNPs and AuNPs, regardless of NP type (Ag vs. Au), concentration, surface ligand (citrate or tannic acid), or size. An inflammatory response was, however, observed in response to 20 nm AgNPs and 20 nm AuNPs, where significant differences in the release of interleukin (IL)-8 but not IL-6 were observed. Additional data demonstrated that increased IL-8 secretion was strongly dependent on both nanoparticle size and concentration. Overall these data suggest that, while not acutely toxic, occupational exposure to AuNPs and AgNPs may trigger a significant inflammatory response in alveolar epithelium. Moreover, the differential responses in IL-8 and IL-6 secretion suggest that NPs may induce a response pathway that is distinct from those commonly elicited by allergens and pathogens.

  8. Degradation of modified carbon black/epoxy nanocomposite coatings under ultraviolet exposure

    Science.gov (United States)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-10-01

    Degradation of epoxy coatings with and without Carbon Black (CB) nanoparticles under ultraviolet (UV) radiation were investigated using electrochemical impedance spectroscopy (EIS). Sodium dodecyl sulfate (SDS) was used to obtain a good dispersion of CB nanoparticles in a polymer matrix. TEM analysis proved a uniform dispersion of modified CB nanoparticles in epoxy coating. The coatings were subjected to UV radiation to study the degradation behavior and then immersed in 3.5 wt% NaCl. The results showed that the electrochemical behavior of neat epoxy coating was related to the formation and development of microcracks on the surface. The occurrence of microcracks on the surface of the coatings and consequently the penetration of ionic species reduced by adding CB nanoparticles into the formulation of the coatings. CB nanoparticles decreased degradation of CB coatings by absorbing UV irradiation. The ATR-FTIR results showed that decrease in the intensity of methyl group as main peak in presence of 2.5 wt% CB was lower than neat epoxy. In addition, the reduction in impedance of neat epoxy coating under corrosive environment was larger than CB coatings. The CB coating with 2.5 wt% nanoparticles had the highest impedance to corrosive media after 2000 h UV irradiation and 24 h immersion in 3.5 wt% NaCl.

  9. Impact of time-activity patterns on personal exposure to black carbon

    OpenAIRE

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Willems, Hanny; Torfs, Rudi; Wets, Geert

    2011-01-01

    Time-activity patterns are an important determinant of personal exposure to air pollution. This is demonstrated by measuring personal exposure of 16 participants for 7 consecutive days: 8 couples of which one person was a full-time worker and the other was a homemaker; both had a very different time-activity pattern. We used portable aethalometers to measure black carbon levels with a high temporal resolution and a PDA with GPS-logger and electronic diary. The exposure to black carbon differs...

  10. Self-Assembly of Oligosaccharide-b-PMMA Block Copolymer Systems: Glyco-Nanoparticles and Their Degradation under UV Exposure.

    Science.gov (United States)

    Zepon, Karine M; Otsuka, Issei; Bouilhac, Cécile; Muniz, Edvani C; Soldi, Valdir; Borsali, Redouane

    2016-05-10

    This paper discusses the self-assembly of oligosaccharide-containing block copolymer and the use of ultraviolet (UV) to obtain nanoporous glyco-nanoparticles by photodegradation of the synthetic polymer block. Those glyco-nanoparticles consisting of oligosaccharide-based shell and a photodegradable core domain were obtained from the self-assembly of maltoheptaose-block-poly(methyl methacrylate) (MH-b-PMMA48) using the nanoprecipitation protocol. MH-b-PMMA48 self-assembled into well-defined spherical micelles (major compound) with a hydrodynamic radius (Rh) of ca. 10 nm and also into large compound micellar aggregates (minor compound) with an Rh of ca. 65 nm. The oligosaccharide shells of these glyco-nanoparticles were cross-linked through the Michael-type addition of divinyl sulfone under dilute conditions to minimize the intermicellar cross-linking. The core domain photodegradation of the cross-linked glyco-nanoparticles was induced under exposure to 254 nm UV radiation, resulting in porous glyco-nanoparticles with an Rh of ca. 44 nm. The morphology of the cross-linked shell and the core photodegradation of these glyco-nanoparticles were characterized using static light scattering, dynamic light scattering, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, field-emission gun-scanning electron microscopy, and transmission electron microscopy. The innovative aspect of this approach concerns the fact that after removing the PMMA domains the porous nanoparticles are mostly composed of biocompatible and nontoxic oligosaccharides. PMID:27054350

  11. Self-assembly of Silver Nanoparticles and Multiwall Carbon Nanotubes on Decomposed GaAs Surfaces

    Directory of Open Access Journals (Sweden)

    Unnikrishnan NV

    2010-01-01

    Full Text Available Abstract Atomic Force Microscopy complemented by Photoluminescence and Reflection High Energy Electron Diffraction has been used to study self-assembly of silver nanoparticles and multiwall carbon nanotubes on thermally decomposed GaAs (100 surfaces. It has been shown that the decomposition leads to the formation of arsenic plate-like structures. Multiwall carbon nanotubes spin coated on the decomposed surfaces were mostly found to occupy the depressions between the plates and formed boundaries. While direct casting of silver nanoparticles is found to induce microdroplets. Annealing at 300°C was observed to contract the microdroplets into combined structures consisting of silver spots surrounded by silver rings. Moreover, casting of colloidal suspension consists of multiwall carbon nanotubes and silver nanoparticles is observed to cause the formation of 2D compact islands. Depending on the multiwall carbon nanotubes diameter, GaAs/multiwall carbon nanotubes/silver system exhibited photoluminescence with varying strength. Such assembly provides a possible bottom up facile way of roughness controlled fabrication of plasmonic systems on GaAs surfaces.

  12. Green synthesis of carbon-supported nanoparticle catalysts by physical vapor deposition on soluble powder substrates

    OpenAIRE

    Hee-Young Park; Injoon Jang; Namgee Jung; Young-Hoon Chung; Jae Yoon Ryu; In Young Cha; Hyung Juhn Kim; Jong Hyung Jang; Sung Jong Yoo

    2015-01-01

    Metal and metal oxide nanoparticles (NPs) supported on high surface area carbon (NP/Cs) were prepared by the physical vapor deposition of bulk materials on an α-D-glucose (Glu) substrate, followed by the deposition of the NPs on carbon supports. Using Glu as a carrier for the transport of NPs from the bulk materials to the carbon support surfaces, ultrafine NPs were obtained, exhibiting a stabilizing effect through OH moieties on the Glu surfaces. This stabilizing effect was strong enough to ...

  13. Molecular dynamics study of the stability of a carbon nanotube atop a catalytic nanoparticle

    OpenAIRE

    Verkhovtsev, Alexey V.; Schramm, Stefan; Solov'yov, Andrey V.

    2014-01-01

    The stability of a single-walled carbon nanotube placed on top of a catalytic nickel nanoparticle is investigated by means of molecular dynamics simulations. As a case study, we consider the $(12,0)$ nanotube consisting of 720 carbon atoms and the icosahedral Ni$_{309}$ cluster. An explicit set of constant-temperature simulations is performed in order to cover a broad temperature range from 400 to 1200 K, at which a successful growth of carbon nanotubes has been achieved experimentally by mea...

  14. Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

    International Nuclear Information System (INIS)

    This paper describes the isolation of carbon nanoparticles (CNPs) from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains

  15. Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

    Directory of Open Access Journals (Sweden)

    Sheena Varghese

    2013-01-01

    Full Text Available This paper describes the isolation of carbon nanoparticles (CNPs from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains.

  16. Synthesis of carbon-encapsulated iron carbide/iron nanoparticles from phenolic-formaldehyde resin and ferric nitrate

    International Nuclear Information System (INIS)

    Carbon-encapsulated iron carbide/iron nanoparticles have been synthesized on a large scale by the heat treatment of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate. The effects of heating temperature on the morphologies and structures of carbonized products were investigated using transmission electron microscope, high-resolution transmission electron microscope and X-ray diffraction measurements. The products with diameter distribution of 20-100 nm consisted mainly of spheroidal nanoparticles separated by hollow onion-like carbon nanoparticles.

  17. Hyaluronic acid modified mesoporous carbon nanoparticles for targeted drug delivery to CD44-overexpressing cancer cells

    Science.gov (United States)

    Wan, Long; Jiao, Jian; Cui, Yu; Guo, Jingwen; Han, Ning; Di, Donghua; Chang, Di; Wang, Pu; Jiang, Tongying; Wang, Siling

    2016-04-01

    In this paper, hyaluronic acid (HA) functionalized uniform mesoporous carbon spheres (UMCS) were synthesized for targeted enzyme responsive drug delivery using a facile electrostatic attraction strategy. This HA modification ensured stable drug encapsulation in mesoporous carbon nanoparticles in an extracellular environment while increasing colloidal stability, biocompatibility, cell-targeting ability, and controlled cargo release. The cellular uptake experiments of fluorescently labeled mesoporous carbon nanoparticles, with or without HA functionalization, demonstrated that HA-UMCS are able to specifically target cancer cells overexpressing CD44 receptors. Moreover, the cargo loaded doxorubicin (DOX) and verapamil (VER) exhibited a dual pH and hyaluronidase-1 responsive release in the tumor microenvironment. In addition, VER/DOX/HA-UMCS exhibited a superior therapeutic effect on an in vivo HCT-116 tumor in BALB/c nude mice. In summary, it is expected that HA-UMCS will offer a new method for targeted co-delivery of drugs to tumors overexpressing CD44 receptors.

  18. Solvothermal synthesis of green-fluorescent carbon nanoparticles and their application

    International Nuclear Information System (INIS)

    A novel solvothermal approach to synthesize green-fluorescent carbon nanoparticles (CNPs) was developed using L-ascorbic acid as the carbon source, glycol and triple distilled water as the solvent. The CNPs emit strong green fluorescence under UV irradiation, and the fluorescence intensity showed a good linear relationship with pH value within a certain range. Direct yeast cell labeling was achieved through cell endocytosis of these CNPs. - Highlights: ► A one-step approach to synthesize fluorescent carbon nanoparticles was developed. ► A linear relationship between fluorescence intensity and pH value was observed. ► Direct labeling of yeast cells was realized successfully with the CNPs.

  19. A solvothermal method to synthesize fluorescent carbon nanoparticles and application to photocatalysis and electrocatalysis.

    Science.gov (United States)

    Hongren, Li; Feng, Li; Aimin, Deng

    2015-09-01

    A novel solvothermal approach to synthesize fluorescent carbon nanoparticles (CNPs) was developed using glucose and ammonium oxalate as the carbon source, and glycol as the solvent. The solution of as-prepared CNPs emitted blue-green fluorescence under ultraviolet (UV) light at 365 nm, and the carbon nanoparticle formation was investigated through XRD, TEM, DLS, FT-IR, UV, PL, XPS. The particle was well dispersed with an average diameter of about 10-30 nm. In contrast with previous methods, in this synthesis process neither strong acid treatment nor further surface modification was necessary. The solution of as-prepared CNPs were applied to photocatalytic degradation of mountain green in the present H2 O2 , and the decolorization rate was over 97% when the reaction time was more than 7 h under visible light. The as-prepared CNPs were also applied to electrocatalysis and showed excellent electrocatalytic activity. PMID:25408385

  20. Laser assisted synthesis of carbon nanoparticles with controlled viscosities for printing applications.

    Science.gov (United States)

    Bagga, K; McCann, R; Wang, M; Stalcup, A; Vázquez, M; Brabazon, D

    2015-06-01

    High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5nm to 50nm with mean size of 18nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerol-water and isopropanol-water. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fourier-transform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative method to engineer carbon nanoparticles and their potential use as a ligand-free nano-ink for ink jet printing (jetting) applications. PMID:25465202

  1. Synthesis and characterization of silver-carbon nanoparticles produced by high-current pulsed arc

    Energy Technology Data Exchange (ETDEWEB)

    Maya, F., E-mail: fermr@correo.unam.m [Departamento de Microscopia Electronica, Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Chihuahua, Chih., CP 3110 (Mexico); Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Muhl, S.; Pena, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Miki-Yoshida, M. [Departamento de Microscopia Electronica, Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Chihuahua, Chih., CP 3110 (Mexico)

    2009-12-31

    In this paper, we report the formation of silver-carbon encapsulated metal nanoparticles (EMN's) using a high-current pulsed arc system in an argon atmosphere. The deposits were studied by Optical Extinction Spectroscopy (OES), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM); the chemical analysis of the deposits was performed using Energy Dispersion X-ray spectroscopy (EDX). Using the total nanoparticle diameter, the bulk crystalline density of silver and an estimate amorphous carbon (a-C) density we have calculated the size of the silver nucleus and the thickness of the a-C coating as a function of the argon gas pressure. The OES spectra of the EMN's exhibited two peaks characteristic of the Surface Plasmon Resonance (SPR) of elongated/very close silver nanoparticles; a subsequent thermal annealing strongly increased the SPR peaks. The double peak SPR spectra were modeled using calculations based on the existence of silver nanoparticles in the form of prolate spheroids. The main advantage of our preparation method is that the metal nanoparticles are encapsulated in a-C from the beginning and this layer acts as an efficient chemical barrier.

  2. Synthesis and characterization of silver-carbon nanoparticles produced by high-current pulsed arc

    International Nuclear Information System (INIS)

    In this paper, we report the formation of silver-carbon encapsulated metal nanoparticles (EMN's) using a high-current pulsed arc system in an argon atmosphere. The deposits were studied by Optical Extinction Spectroscopy (OES), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM); the chemical analysis of the deposits was performed using Energy Dispersion X-ray spectroscopy (EDX). Using the total nanoparticle diameter, the bulk crystalline density of silver and an estimate amorphous carbon (a-C) density we have calculated the size of the silver nucleus and the thickness of the a-C coating as a function of the argon gas pressure. The OES spectra of the EMN's exhibited two peaks characteristic of the Surface Plasmon Resonance (SPR) of elongated/very close silver nanoparticles; a subsequent thermal annealing strongly increased the SPR peaks. The double peak SPR spectra were modeled using calculations based on the existence of silver nanoparticles in the form of prolate spheroids. The main advantage of our preparation method is that the metal nanoparticles are encapsulated in a-C from the beginning and this layer acts as an efficient chemical barrier.

  3. Decorating multi-walled carbon nanotubes with nickel nanoparticles for selective hydrogenation of citral

    Science.gov (United States)

    Tang, Yuechao; Yang, Dong; Qin, Feng; Hu, Jianhua; Wang, Changchun; Xu, Hualong

    2009-08-01

    The nanocomposites of multi-walled carbon nanotubes (MWNTs) decorated with nickel nanoparticles were conveniently prepared by a chemical reduction of nickel salt in the present of poly(acrylic acid) grafted MWNTs (PAA- g-MWNTs). Due to the strong interaction between Ni 2+ and -COOH, PAA- g-MWNTs became an excellent supporting material for Ni nanoparticles. The morphology and distribution of Ni nanoparticles on the surface of MWNTs were greatly influenced by the reduction temperatures, the experimental results also showed that the distribution of Ni nanoparticles was greatly improved while the MWNTs were modified by poly(acrylic acid) (PAA). The hydrogenation activity and selectivity of MWNTs decorated with Ni nanoparticles (Ni-MWNTs) for α, β-unsaturated aldehyde (citral) were also studied, and the experimental results showed that the citronellal, an important raw material for flavoring and perfumery industries, is the favorable product with a percentage as high as 86.9%, which is 7 times higher than that of catalyst by Ni-supported active carbon (Ni-AC).

  4. Same Exposure, Various Clinical Pictures: The Carbon Monoxide Enigma

    Directory of Open Access Journals (Sweden)

    Musa Salmanoglu

    2013-02-01

    Full Text Available -Children and adolescents exposed to the same source of carbon monoxide have been shown to demonstrate different clinical pictures (1,2. The same condition probably may be extrapolated between children with varying ages and hence lung surface areas. Smaller children will receive larger doses of carbon monoxide, because they have greater lung surface area/body weight ratios and increased minute volumes/weight ratios. As carbon monoxide accumulation is expected to be more significant nearer to the ground, another explanation for varying clinical pictures in poisoning events may be the different level of sleeping positions of the casualties. Herein, we report a cluster poisoning of carbon monoxide affecting 5 children from the same family at the same time but in different clinical pictures. [TAF Prev Med Bull 2013; 12(1.000: 118-118

  5. Acute systemic exposure to silver-based nanoparticles induces hepatotoxicity and NLRP3-dependent inflammation.

    Science.gov (United States)

    Ramadi, Khalil B; Mohamed, Yassir A; Al-Sbiei, Ashraf; Almarzooqi, Saeeda; Bashir, Ghada; Al Dhanhani, Aisha; Sarawathiamma, Dhanya; Qadri, Shahnaz; Yasin, Javed; Nemmar, Abderrahim; Fernandez-Cabezudo, Maria J; Haik, Yousef; Al-Ramadi, Basel K

    2016-10-01

    Nanoparticles (NPs) are increasingly being commercialized for use in biomedicine. NP toxicity following acute or chronic exposure has been described, but mechanistic insight into this process remains incomplete. Recent evidence from in vitro studies suggested a role for NLRP3 in NP cytotoxicity. In this study, we investigated the effect of systemic administration of composite inorganic NP, consisting of Ag:Cu:B (dose range 1-20 mg/kg), on the early acute (4-24 h post-exposure) and late phase response (96 h post-exposure) in normal and NLRP3-deficient mice. Our findings indicate that systemic exposure (≥2 mg/kg) was associated with acute liver injury due to preferential accumulation of NP in this organ and resulted in elevated AST, ALT and LDH levels. Moreover, within 24 h of NP administration, there was a dose-dependent increase in intraperitoneal neutrophil recruitment and upregulation in gene expression of several proinflammatory mediators, including TNF-α, IL-1β and S100A9. Histological analysis of liver tissue revealed evidence of dose-dependent hepatocyte necrosis, increase in sinusoidal Kupffer cells, lobular granulomas and foci of abscess formation which were most pronounced at 24 h following NP administration. NP deposition in the liver led to a significant upregulation in gene expression of S100A9, an endogenous danger signal recognition molecule of phagocytes, IL-1β and IL-6. The extent of proinflammatory cytokine activation and hepatotoxicity was significantly attenuated in mice deficient in the NLRP3 inflammasome, demonstrating the critical role of this innate immune system recognition receptor in the response to NP. PMID:26956548

  6. Exposure to carbon monoxide, respirable suspended particulates, and volatile organic compounds while commuting by bicycle

    International Nuclear Information System (INIS)

    A portable air sampling system has been used to assess exposures to various substances while commuting by bicycle in an urban area. The major source of pollutants in this situation is motor vehicle exhaust emissions. Carbon monoxide, measured by electrochemical detection, was found at peak concentrations in excess of 62 ppm, with mean values over 16 individual 35-mm journeys being 10.5 ppm. Respirable suspended particulates, averaged over each journey period, were found at higher concentrations (mean 130 μg m-3) than would be expected in indoor situations. Mean exposure to benzene (at 56 μg m-3) and other aromatic volatile organic compounds was also relatively high. The influence of wind conditions on exposure was found to be significant. Commuting exposures to carbon monoxide, respirable suspended particulates, and aromatic VOCs were found to be higher than exposures in a busy high street and on common parkland

  7. Activated carbon from pyrolysed sugarcane bagasse: Silver nanoparticle modification and ecotoxicity assessment.

    Science.gov (United States)

    Gonçalves, Suely Patrícia C; Strauss, Mathias; Delite, Fabrício S; Clemente, Zaira; Castro, Vera L; Martinez, Diego Stéfani T

    2016-09-15

    Activated carbon from pyrolysed sugarcane bagasse (ACPB) presented pore size ranges from 1.0 to 3.5nm, and surface area between 1200 and 1400m(2)g(-1) that is higher than commonly observed to commercial activated carbon. The ACPB material was successfully loaded with of silver nanoparticles with diameter around 35nm (0.81wt.%). X-ray photoelectron spectroscopy (XPS) analyses showed that the material surface contains metallic/Ag(0) (93.60wt.%) and ionic/Ag(+) states (6.40wt.%). The adsorption capacity of organic model molecules (i.e. methylene blue and phenol) was very efficient to ACPB and ACPB loaded with silver nanoparticles (ACPB-AgNP), indicating that the material modification with silver nanoparticles has not altered its adsorption capacity. ACPB-AgNP inhibited bacteria growth (Escherichia coli), it is a promising advantage for the use of these materials in wastewater treatment and water purification processes. However, ACPB-AgNP showed environmental risks, with toxic effect to the aquatic organism Hydra attenuata (i.e. LC50 value of 1.94mgL(-1)), and it suppressed root development of Lycopersicum esculentum plant (tomato). Finally, this work draw attention for the environmental implications of activated carbon materials modified with silver nanoparticles. PMID:27039274

  8. Plasma Syntheses of Carbon Nanotube-Supported Pt-Pd Nanoparticles

    Science.gov (United States)

    Song, Ye; Wang, Qi; Meng, Yuedong

    2016-04-01

    It is reported that the highly dispersed Pt nanoparticles on carbon nanotubes can be synthesized under mild conditions by in situ plasma treatment. The carbon nanotube was pretreated by O2 plasma to transform into oxide carbon nanotubes (O-CNTs), and then it was mixed with the precursors (the mixture of H2PtCl6 and PdCl6). After that, the O-CNTs and the precursors were simultaneously treated by H2 plasma. The precursors were transformed into Pt-Pd nanoparticles (NPs) and the O-CNTs transformed into CNT. The synthesized CNT-based Pt-Pd nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. All the analysis showed that the Pt-Pd nanoparticles were deposited on CNT as a form of face-centered cubical structure. supported by National Natural Science Foundation of China (Nos. 11305218,11575253), the Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2015262), the CASHIPS Director's Fund (No. YZJJ201505) and Anhui Provincial Natural Science Foundation for Distinguished Young Scholars of China (No. 1608085J03)

  9. Electrochemical stability of citrate-capped gold nanoparticles electrostatically assembled on amine-modified glassy carbon

    International Nuclear Information System (INIS)

    The stability of citrate-capped gold nanoparticles assembled on covalently attached ethylenediamine films on glassy carbon was probed using cyclic voltammetry and scanning electron microscopy. The accessible potential windows in 0.01 M HClO4 and phosphate buffer (pH 7.4) were found to be very similar to those for re-constructed polycrystalline bulk gold. At the nanoparticle electrodes, gold is dissolved at high positive potentials and re-deposited at lower potentials resulting in the formation of fewer, larger particles. The electrografted amine layer does not limit the stability range and citrate-capping groups do not stabilise the nanoparticles to oxidation. In addition to the structural stability of the nanoparticle electrodes, preliminary investigations of the stability of their activity for voltammetric analyses were also undertaken. Repeated voltammetric reduction of H2O2 at the nanoparticle electrodes showed excellent reproducibility indicating that the nanoparticle surface maintained a constant activity for the redox process. In contrast, a re-constructed polycrystalline bulk gold electrode did not exhibit a stable response under the same conditions.

  10. Laser assisted synthesis of carbon nanoparticles with controlled viscosities for printing applications

    OpenAIRE

    Bagga, Komal; McCann, R.; Wang, M.; Stalcup, Apryll; Vazquez, Mercedes; Brabazon, Dermot

    2015-01-01

    High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5 nm to 50 nm with mean size of 18 nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12 mPa.s were...

  11. Glassy carbon electrode modified with gold nanoparticles for ractopamine and metaproterenol sensing

    Science.gov (United States)

    Duan, Jiahua; He, Dawei; Wang, Wenshuo; Liu, Yongchuan; Wu, Hongpeng; Wang, Yongsheng; Fu, Ming

    2013-06-01

    In this Letter, the gold nanoparticles (AuNPs) were used as an enhanced material for selective detection of ractopamine and metaproterenol with electrochemical methods. The morphology and size of gold nanoparticles were characterized by scanning electron microscopy and absorption spectrum. Meanwhile, the electrical properties of modified glass carbon electrode (GCE) were studied by electrochemical impedance spectroscopy. The electrochemical behaviors of ractopamine and metaproterenol were well explained by PM3 calculated method and cyclic voltammetry. Importantly, the ractopamine and metaproterenol were effectively detected. The detection range has been broadened to (10-9-10-5 M) and the detection time has been shortened to a few minutes.

  12. Platinum-cobalt bimetallic nanoparticles in hollow carbon nanospheres for hydrogenolysis of 5-hydroxymethylfurfural

    Science.gov (United States)

    Wang, Guang-Hui; Hilgert, Jakob; Richter, Felix Herrmann; Wang, Feng; Bongard, Hans-Josef; Spliethoff, Bernd; Weidenthaler, Claudia; Schüth, Ferdi

    2014-03-01

    The synthesis of 2,5-dimethylfuran (DMF) from 5-hydroxymethylfurfural (HMF) is a highly attractive route to a renewable fuel. However, achieving high yields in this reaction is a substantial challenge. Here it is described how PtCo bimetallic nanoparticles with diameters of 3.6 ± 0.7 nm can solve this problem. Over PtCo catalysts the conversion of HMF was 100% within 10 min and the yield to DMF reached 98% after 2 h, which substantially exceeds the best results reported in the literature. Moreover, the synthetic method can be generalized to other bimetallic nanoparticles encapsulated in hollow carbon spheres.

  13. Nanoparticles containing allotropes of carbon have genotoxic effects on glioblastomamultiforme cells

    Directory of Open Access Journals (Sweden)

    Hinzmann M

    2014-05-01

    Full Text Available Mateusz Hinzmann,1 Slawomir Jaworski,1 Marta Kutwin,1 Joanna Jagiello,2 Rafal Kozinski,2 Mateusz Wierzbicki,1 Marta Grodzik,1 Ludwika Lipinska,2 Ewa Sawosz,1 Andrè Chwalibog31Division of Nanobiotechnology, Warsaw University of Life Sciences, 2Institute of Electronic Materials Technology, Warsaw, Poland; 3Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Copenhagen, DenmarkAbstract: The carbon-based nanomaterial family consists of nanoparticles containing allotropes of carbon, which may have a number of interactions with biological systems. The objective of this study was to evaluate the toxicity of nanoparticles comprised of pristine graphene, reduced graphene oxide, graphene oxide, graphite, and ultradispersed detonation diamond in a U87 cell line. The scope of the work consisted of structural analysis of the nanoparticles using transmission electron microscopy, evaluation of cell morphology, and assessment of cell viability by Trypan blue assay and level of DNA fragmentation of U87 cells after 24 hours of incubation with 50 µg/mL carbon nanoparticles. DNA fragmentation was studied using single-cell gel electrophoresis. Incubation with nanoparticles containing the allotropes of carbon did not alter the morphology of the U87 cancer cells. However, incubation with pristine graphene and reduced graphene oxide led to a significant decrease in cell viability, whereas incubation with graphene oxide, graphite, and ultradispersed detonation diamond led to a smaller decrease in cell viability. The results of a comet assay demonstrated that pristine graphene, reduced graphene oxide, graphite, and ultradispersed detonation diamond caused DNA damage and were therefore genotoxic in U87 cells, whereas graphene oxide was not.Keywords: nanostructures, graphene, graphite, diamond, glioblastoma multiforme, geno toxicity

  14. Two types of carbon nanocomposites: Graphite encapsulated iron nanoparticles and thin carbon nanotubes supported on thick carbon nanotubes, synthesized using PECVD

    International Nuclear Information System (INIS)

    In this work, graphite encapsulated Fe nanoparticles and thin carbon nanotubes (CNTs) supported on the pristine CNTs, respectively, were synthesized using plasma enhanced chemical vapor deposition via efficiently controlling the flow rate of discharging CH4 and H2 gas. The properties of the obtained hybrid materials were characterized with superconducting quantum interference and field emission measurements. The results showed that the encapsulated Fe nanoparticles had diameters ranging from 1 to 30 nm, and this hybrid nanocomposite exhibited a ferromagnetic behavior at room temperature. Thin CNTs with an average diameter of 6 nm were attached to the surface of the prepared CNTs, which exhibited a lower turn-on field and higher emission current density than the pristine CNTs. The Fe nanoparticles either encapsulated with graphite or used as catalyst for thin CNTs growth were all originated from the pyrolysis of ferrocene. - Graphical abstract: Graphite encapsulated Fe nanoparticles and thin carbon nanotubes supported on the pristine carbon nanotubes, respectively, were synthesized using plasma enhanced chemical vapor deposition.

  15. Glassy Carbon Electrode-Supported Au Nanoparticles for the Glucose Electrooxidation: On the Role of Crystallographic Orientation

    OpenAIRE

    M. Guerra-Balcázar; J. Torres-González; I. Terol-Villalobos; J. Morales-Hernández; F. Castañeda

    2012-01-01

    Glucose electrooxidation in alkaline solution was examined using glassy carbon electrodes modified with Au nanoparticles. Au nanoparticles were prepared following the two-phase protocol and characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction spectroscopy (XRD), and cyclic voltammetry (CV). It was found that, under the study conditions, it is possible to obtain nanoparticles between 1 and 5 nm; also it was found that the crystallographic orientation ...

  16. Sensor for hydrogen peroxide using a hemoglobin-modified glassy carbon electrode prepared by enhanced loading of silver nanoparticle onto carbon nanospheres via spontaneous polymerization of dopamine

    International Nuclear Information System (INIS)

    We have developed a simple and efficient method for the enhanced loading of silver nanoparticles onto carbon nanospheres, and how this method can be used to design an electrochemical sensor for hydrogen peroxide (HP). A glassy carbon electrode was modified with hemoglobin, carbon nanospheres, and by enhanced loading of silver nanoparticles onto the carbon nanospheres via spontaneous polymerization of dopamine. The hemoglobin exhibits a remarkable electrocatalytic activity for the reduction of HP. The electrochemical response to HP is linear range in the 1.0-147.0 μM concentration range, with a detection limit of 0.3 μM at a signal-to-noise ratio of 3. (author)

  17. Hemocyte responses of Dreissena polymorpha following a short-term in vivo exposure to titanium dioxide nanoparticles: Preliminary investigations

    International Nuclear Information System (INIS)

    The widespread use of titanium-based nanoparticles and their environmental release may pose a significant risk to aquatic organisms within freshwater ecosystems. Suspension-feeder invertebrates like bivalve molluscs represent a unique target group for nanoparticle toxicology. The aim of this work was to investigate the short-term responses of Dreissena polymorpha hemocytes after in vivo exposure to titanium dioxide nanoparticles (TiO2 NP). For this purpose, freshwater mussels were exposed to P25 TiO2 NP at the concentrations of 0.1, 1, 5 and 25 mg/L during 24 h. Viability, phagocytosis activity and mitogen activated protein kinase (MAPK) phosphorylation level of ERK 1/2 and p38 in hemocytes extracted from exposed mussels were compared to those from control specimens. Results demonstrated an inhibition of the phagocytosis activity after exposure to TiO2 NP at 0.1 and 1 mg/L. Similar trends, albeit less pronounced, were reported for higher concentrations of NP. Transmission electron microscopy showed for the first time the internalization of TiO2 NP into Dreissena polymorpha hemocytes. Besides, exposure to NP increased the ERK 1/2 phosphorylation levels in all treatments. Concerning the phosphorylation level of p38, only exposures to 5 and 25 mg/L of NP induced significant p38 activation in comparison to that of the control. Finally, these short-term effects observed at environmentally relevant concentrations highlighted the need for further studies concerning ecotoxicological evaluation of nanoparticle release into an aquatic environment. -- Highlights: ► Phagocytosis inhibition at TiO2 NP exposure concentrations of 0.1 and 1 mg/L. ► Internalization of TiO2 NP in freshwater mussel hemocytes. ► Increased phosphorylation level of p38 and ERK 1/2 after in vivo exposure to TiO2 NP.

  18. Cytotoxic effects of gold nanoparticles exposure employing in vitro animal cell culture system as part of nanobiosafety

    Science.gov (United States)

    Ambwani, Sonu; Kakade Datta, P.; Kandpal, Deepika; Arora, Sandeep; Ambwani, Tanuj Kumar

    2016-04-01

    Metal Nanoparticles are exploited in different fields that include biomedical sector where they are utilized in drug and gene delivery, biosensors, cancer treatment and diagnostic tools. Despite of their benefits, there has been serious concerns about possible side effects of several nanoparticles. Gold nanoparticles (AuNPs) are exploited for bio-imaging, biosensing, drug delivery, transfection and diagnosis. These nanoparticles may get released into the environment in high amounts at all stages of production, recycling and disposal. Since the manufacture and use of nanoparticles are increasing, humans/ animals are more likely to be exposed occupationally or via consumer products and the environment. The emergence of the new field of nanotoxicity has spurred great interest in a wide variety of materials and their possible effects on living systems. Animal cell culture system is considered as a sensitive indicator against exposure of such materials. Keeping in view the above scenario, present study was carried out to evaluate effect of AuNPs exposure in primary and cell line culture system employing chicken embryo fibroblast (CEF) culture and HeLa cell line culture through MTT assay. Minimum cytotoxic dose was found to be 60 µg/ml and 50 µg/ml in CEF and HeLa cells, respectively. Thus, it could be inferred that even a very low concentration of AuNPs could lead to cytotoxic effects in cell culture based studies.

  19. Application of a pilot control banding tool for risk level assessment and control of nanoparticle exposures

    Energy Technology Data Exchange (ETDEWEB)

    Paik, S Y; Zalk, D M; Swuste, P

    2008-03-03

    Control Banding (CB) strategies offer simplified solutions for controlling worker exposures to constituents that are found in the workplace in the absence of firm toxicological and exposure data. These strategies may be particularly useful in nanotechnology applications, considering the overwhelming level of uncertainty over what nanomaterials and nanotechnologies present as potential work-related health risks, what about these materials might lead to adverse toxicological activity, how risk related to these might be assessed, and how to manage these issues in the absence of this information. This study introduces a pilot CB tool or 'CB Nanotool' that was developed specifically for characterizing the health aspects of working with engineered nanoparticles and determining the level of risk and associated controls for five ongoing nanotechnology-related operations being conducted at two Department of Energy (DOE) research laboratories. Based on the application of the CB Nanotool, four of the five operations evaluated in this study were found to have implemented controls consistent with what was recommended by the CB Nanotool, with one operation even exceeding the required controls for that activity. The one remaining operation was determined to require an upgrade in controls. By developing this dynamic CB Nanotool within the realm of the scientific information available, this application of CB appears to be a useful approach for assessing the risk of nanomaterial operations, providing recommendations for appropriate engineering controls, and facilitating the allocation of resources to the activities that most need them.

  20. A novel sol–gel process to facilely synthesize Ni3Fe nanoalloy nanoparticles supported with carbon and silica

    International Nuclear Information System (INIS)

    Graphical abstract: The TEM and HRTEM images and the magnetization curves taken in both zero-field-cooled (ZFC) and field-cooled (FC) modes of Ni3Fe nanoparticles calcined at 300 °C for 2 h under Ar flowing. Display Omitted - Highlights: • Ultrafine Ni3Fe nanoalloy nanoparticles were synthesized via a modified novel sol–gel process. • The prepared Ni3Fe nanoalloy nanoparticles have a narrow size distribution. • The Ni3Fe nanoparticles exhibit superparamagnetic behaviors at room temperature. - Abstract: In this paper, we present a modified novel silica sol–gel process and explored the possibility, for the first time, to synthesize binary nanoalloy nanoparticles. We successfully prepared ultrafine Ni3Fe nanoparticles supported with carbon and silica via this simple one-pot reaction without H2 reduction. X-ray diffraction (XRD) and selected area electron diffraction (SAED) investigations of the Ni3Fe nanoparticles show that the nanoparticles have a face-centered-cubic (fcc) crystal structure. The TEM images show that grain sizes of Ni3Fe nanoparticles have a narrow size distribution. Moreover, the grain size of the nanoparticles is not very sensitive to the elevated annealing temperature. The Ni3Fe nanoparticles exhibit typical superparamagnetic behavior at room temperature, and the blocking temperatures (TB) are determined by the temperature-dependent magnetization (M–T curves) measurements. This novel silica sol–gel method is expected to have broad applications in synthesizing nanoalloy nanoparticles

  1. Catalytic decomposition of low level ozone with gold nanoparticles supported on activated carbon

    Institute of Scientific and Technical Information of China (English)

    Pengyi ZHANG; Bo ZHANG; Rui SHI

    2009-01-01

    Highly dispersed gold nanoparticles were supported on coal-based activated carbon (AC) by a sol immobilization method and were used to investigate their catalytic activity for low-level ozone decomposition at ambient temperature. Nitrogen adsorption-desorption,scanning electron microscope (SEM), and X-ray photo-electron spectroscopy (XPS) were used to characterize the catalysts before and after ozone decomposition. The results showed that the supported gold nanoparticles prepared with microwave heating were much smaller and more uniformly dispersed on the activated carbon than those prepared with traditional conduction heating, exhibiting higher catalytic activity for ozone decomposition. The pH values of gold precursor solution significantly influenced the catalytic activity of supported gold for ozone decomposition, and the best pH value was 8. In the case of space velocity of 120000 h-1, inlet ozone concentration of 50mg/m3, and relative humidity of 45%, the Au/AC catalyst maintained the ozone removal ratio at 90.7% after 2500 min. After being used for ozone decomposition, the surface carbon of the catalyst was partly oxidized and the oxygen content increased accordingly, while its specific surface area and pore volume only decreased a little.Ozone was mainly catalytically decomposed by the gold nanoparticles supported on the activated carbon.

  2. Influence of Magnetic Losses on Microwave Absorption by Carbon-Nanotube Nanocomposites with a Low Concentration of Ferromagnetic Nanoparticles

    Science.gov (United States)

    Avramchuk, A. V.; Kasperovich, M. M.; Pevneva, N. A.; Gusinsky, A. V.; Korolik, O. V.; Tivanov, M. S.; Shulitski, B. G.; Labunov, V. A.; Danilyuk, A. L.; Komissarov, I. V.; Prischepa, S. L.

    2016-05-01

    The absorption properties of magnetic nanocomposites based on carbon nanotubes with a low concentration of ferromagnetic nanoparticles have been investigated in the 78-118 GHz frequency range. A correlation was established between the absorption properties of the nanocomposites and the character of the magnetostatic interaction between nanoparticles.

  3. Synthesis of few-walled carbon nanotube-Rh nanoparticles by arc discharge: Effect of selective oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yanfeng, E-mail: zyfshu@gmail.com

    2012-06-15

    Highly crystalline rhodium (Rh) nanoparticles supported on carbon nanotubes were prepared by selective oxidation method. Carbon nanotubes and FeRh nanoparticles were simultaneously generated in hydrogen arc plasma. The as-grown nanomaterials can be purified by heat treatment in open air and by soaking in HCl. X-ray diffraction and selected area electron diffraction results reveal that as-grown FeRh nanoparticles have a typical chemical CsCl-type structure which can be transformed into a face-centered cubic structure by thermal annealing in the purification process. The purification process is selective toward the removal of the amorphous carbon coating the nanoparticles, and transforms Fe to Fe{sub 2}O{sub 3}. Fe{sub 2}O{sub 3} can be easily dissolved in hydrochloric acid, leaving carbon nanotubes-Rh nanoparticles. Rh nanoparticles with diameters of 2-60 nm are deposited uniformly on the surface of the carbon nanotube bundles. This simple and selective chemistry offers a new process for synthesizing and controlling Fe content in carbon nanotube-FeRh nanoparticles. Highlights: Black-Right-Pointing-Pointer High-crystallinity CNTs and FeRh nanoparticles were simultaneously generated in arc plasma. Black-Right-Pointing-Pointer The diameter distribution of CNTs depends on different gases. Black-Right-Pointing-Pointer Heat treatment in open air and soaking in HCl can convert CNTs-FeRh to CNTs-Rh. Black-Right-Pointing-Pointer The selective oxidation mechanisms of metal nanoparticles and carbon materials differ.

  4. Adsorbent 2D and 3D carbon matrices with protected magnetic iron nanoparticles

    Science.gov (United States)

    Carreño, N. L. V.; Escote, M. T.; Valentini, A.; McCafferty, L.; Stolojan, V.; Beliatis, M.; Mills, C. A.; Rhodes, R.; Smith, C. T. G.; Silva, S. R. P.

    2015-10-01

    We report on the synthesis of two and three dimensional carbonaceous sponges produced directly from graphene oxide (GO) into which functionalized iron nanoparticles can be introduced to render it magnetic. This simple, low cost procedure, wherein an iron polymeric resin precursor is introduced into the carbon framework, results in carbon-based materials with specific surface areas of the order of 93 and 66 m2 g-1, compared to approx. 4 m2 g-1 for graphite, decorated with ferromagnetic iron nanoparticles giving coercivity fields postulated to be 216 and 98 Oe, values typical for ferrite magnets, for 3.2 and 13.5 wt% Fe respectively. The strongly magnetic iron nanoparticles are robustly anchored to the GO sheets by a layer of residual graphite, on the order of 5 nm, formed during the pyrolysis of the precursor material. The applicability of the carbon sponges is demonstrated in their ability to absorb, store and subsequently elute an organic dye, Rhodamine B, from water as required. It is possible to regenerate the carbon-iron hybrid material after adsorption by eluting the dye with a solvent to which it has a high affinity, such as ethanol. The use of a carbon framework opens the hybrid materials to further chemical functionalization, for enhanced chemical uptake of contaminants, or co-decoration with, for example, silver nanoparticles for bactericidal properties. Such analytical properties, combined with the material's magnetic character, offer solutions for environmental decontamination at land and sea, wastewater purification, solvent extraction, and for the concentration of dilute species.

  5. Adsorbent 2D and 3D carbon matrices with protected magnetic iron nanoparticles.

    Science.gov (United States)

    Carreño, N L V; Escote, M T; Valentini, A; McCafferty, L; Stolojan, V; Beliatis, M; Mills, C A; Rhodes, R; Smith, C T G; Silva, S R P

    2015-11-01

    We report on the synthesis of two and three dimensional carbonaceous sponges produced directly from graphene oxide (GO) into which functionalized iron nanoparticles can be introduced to render it magnetic. This simple, low cost procedure, wherein an iron polymeric resin precursor is introduced into the carbon framework, results in carbon-based materials with specific surface areas of the order of 93 and 66 m(2) g(-1), compared to approx. 4 m(2) g(-1) for graphite, decorated with ferromagnetic iron nanoparticles giving coercivity fields postulated to be 216 and 98 Oe, values typical for ferrite magnets, for 3.2 and 13.5 wt% Fe respectively. The strongly magnetic iron nanoparticles are robustly anchored to the GO sheets by a layer of residual graphite, on the order of 5 nm, formed during the pyrolysis of the precursor material. The applicability of the carbon sponges is demonstrated in their ability to absorb, store and subsequently elute an organic dye, Rhodamine B, from water as required. It is possible to regenerate the carbon-iron hybrid material after adsorption by eluting the dye with a solvent to which it has a high affinity, such as ethanol. The use of a carbon framework opens the hybrid materials to further chemical functionalization, for enhanced chemical uptake of contaminants, or co-decoration with, for example, silver nanoparticles for bactericidal properties. Such analytical properties, combined with the material's magnetic character, offer solutions for environmental decontamination at land and sea, wastewater purification, solvent extraction, and for the concentration of dilute species. PMID:26441224

  6. Electric Conductivity of Carbon Nanoparticles Stimulated by Electric Field

    International Nuclear Information System (INIS)

    Host-guest interactions can be the unique method of spin manipulation in nanoscale. Strong changes in spin localization are generated when potential barriers between nanographitic units of activated carbon fibers are modified by interaction with adsorbed molecules. Stronger modifications occur when dipolar guest molecules are stimulated with external electric field. We report experimental results which show the influence of electric field on the spin localization in activated carbon fibers. (authors)

  7. Room-temperature synthesis and electrocatalysis of carbon nanotubes supported palladium–iron alloy nanoparticles

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs) supported palladium–iron bimetallic nanoparticles (Pd–Fe/CNTs) catalyst is synthesized using palladium hexacyanoferrate (PdHCF) as reaction precursor. In this method, the negatively charged PdHCF nanoparticles self-assemble on the positively charged polydiallyldimethylammonium chloride (PDDA) functionalized CNTs through electrostatic interaction, and then are reduced to Pd–Fe alloy nanoparticles by sodium borohydride. The physicochemical properties of Pd–Fe/CNTs are investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). These structural analyses reveal that the Pd–Fe/CNTs catalyst possesses the high alloying degree and the small particle size. Electrochemical measurements show that the eletrocatalytic activity of the Pd–Fe/MWCNTs catalyst for the methanol oxidation is better than that of the Pd/CNTs catalyst, which originates from the synergistic effect between Pd atom and Fe atom

  8. Anodic stripping voltammetry of antimony using gold nanoparticle-modified carbon screen-printed electrodes

    International Nuclear Information System (INIS)

    Carbon screen-printed electrodes (CSPE) modified with gold nanoparticles present an interesting alternative in the determination of antimony using differential pulse anodic stripping voltammetry. Metallic gold nanoparticles deposits have been obtained by direct electrochemical deposition. Scanning electron microscopy measurements show that the electrochemically synthesized gold nanoparticles are deposited in aggregated form. Any undue effects caused by the presence of foreign ions in the solution were also analyzed to ensure that common interferents in the determination of antimony by ASV. The detection limit for Sb(III) obtained was 9.44 x 10-10 M. In terms of reproducibility, the precision of the above mentioned method in %R.S.D. values was calculated at 2.69% (n = 10). The method was applied to determine levels of antimony in seawater samples and pharmaceutical preparations

  9. Morphological Lesions in Mouse Liver and Lungs After Lung Exposure to Carbon Nanotubes

    DEFF Research Database (Denmark)

    Szarek, J.; Mortensen, Alicja; Jackson, P.;

    2013-01-01

    Introduction: Engineered nanoparticles are smaller than 100 nm in at least one direction and designed to improve or achieve new physicochemical properties. Consequently, toxicological properties may also change. Carbon nanotubes have attracted industrial interest due to their unique properties....... Materials and Methods: One day before mating, 30 mice (C57BL/6BomTac, Taconic Europe, Denmark) were given 67 μg multi-walled carbon nanotubes (NM-400, Nanocyl, Belgium) intratracheally (group A). A further 30 control mice (group B) received vehicle (Millipore water with 2% mouse serum). Lungs and liver were...

  10. The efficiency of magnetic carbon activated by iron oxide nanoparticles in removing of Cu (II) from aqueous solutions

    OpenAIRE

    Salehe Salehnia; Behnam Barikbin; Hadighe Dorri

    2016-01-01

    Background and Aim: Copper ions, due to forming complexes with organic and mineral compounds, can have worrying effects on health and environment. In the present study, the effect of powdered magnetic carbon activated by iron-oxide nanoparticles in removing of CU (V; II) from aqueous solutions was assessed. Materials and Methods: This experimental study aimed at determining the effect of powdered magnetic carbon activated  by iron-oxide nanoparticles  parameters including PH, co...

  11. Comparison of cellular toxicity between multi-walled carbon nanotubes and onion-like shell-shaped carbon nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seunghyon [Seoul National University, School of Mechanical and Aerospace Engineering (Korea, Republic of); Kim, Ji-Eun [Korea Research Institute of Standard and Science, Center for NanoSafety Metrology, Division of Convergence Technology (Korea, Republic of); Kim, Daegyu [LG Electronics (Korea, Republic of); Woo, Chang Gyu [Korea Institute of Machinery and Materials, Environmental and Energy Systems Research Division (Korea, Republic of); Pikhitsa, Peter V. [Seoul National University, School of Mechanical and Aerospace Engineering (Korea, Republic of); Cho, Myung-Haing, E-mail: mchotox@snu.ac.kr [Seoul National University, Laboratory of Toxicology, College of Veterinary Medicine (Korea, Republic of); Choi, Mansoo, E-mail: mchoi@snu.ac.kr [Seoul National University, School of Mechanical and Aerospace Engineering (Korea, Republic of)

    2015-09-15

    The cellular toxicity of multi-walled carbon nanotubes (MWCNTs) and onion-like shell-shaped carbon nanoparticles (SCNPs) was investigated by analyzing the comparative cell viability. For the reasonable comparison, physicochemical characteristics were controlled thoroughly such as crystallinity, carbon bonding characteristic, hydrodynamic diameter, and metal contents of the particles. To understand relation between cellular toxicity of the particles and generation of reactive oxygen species (ROS), we measured unpaired singlet electrons of the particles and intracellular ROS, and analyzed cellular toxicity with/without the antioxidant N-acetylcysteine (NAC). Regardless of the presence of NAC, the cellular toxicity of SCNPs was found to be lower than that of MWCNTs. Since both particles show similar crystallinity, hydrodynamic size, and Raman signal with negligible contribution of remnant metal particles, the difference in cell viability would be ascribed to the difference in morphology, i.e., spherical shape (aspect ratio of one) for SCNP and elongated shape (high aspect ratio) for MWCNT.

  12. Comparison of cellular toxicity between multi-walled carbon nanotubes and onion-like shell-shaped carbon nanoparticles

    International Nuclear Information System (INIS)

    The cellular toxicity of multi-walled carbon nanotubes (MWCNTs) and onion-like shell-shaped carbon nanoparticles (SCNPs) was investigated by analyzing the comparative cell viability. For the reasonable comparison, physicochemical characteristics were controlled thoroughly such as crystallinity, carbon bonding characteristic, hydrodynamic diameter, and metal contents of the particles. To understand relation between cellular toxicity of the particles and generation of reactive oxygen species (ROS), we measured unpaired singlet electrons of the particles and intracellular ROS, and analyzed cellular toxicity with/without the antioxidant N-acetylcysteine (NAC). Regardless of the presence of NAC, the cellular toxicity of SCNPs was found to be lower than that of MWCNTs. Since both particles show similar crystallinity, hydrodynamic size, and Raman signal with negligible contribution of remnant metal particles, the difference in cell viability would be ascribed to the difference in morphology, i.e., spherical shape (aspect ratio of one) for SCNP and elongated shape (high aspect ratio) for MWCNT

  13. Real-time monitoring of personal exposures to carbon dioxide

    OpenAIRE

    Gall, Elliott T.; Cheung, Toby; Luhung, Irvan; Schiavon, Stefano; Nazaroff, William W.

    2016-01-01

    Elevated indoor CO2 levels are indicative of insufficient ventilation in occupied spaces and correlate with elevated concentrations of pollutants of indoor origin. Adverse health and well-being outcomes associated with elevated indoor CO2 levels are based on CO2 as a proxy, although some emerging evidence suggests CO2 itself may impact human cognition. Using portable monitors, we conducted an exposure study with 16 subjects in Singapore to understand the levels, dynamics and influencing facto...

  14. Impact of time-activity patterns on personal exposure to black carbon

    Science.gov (United States)

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Willems, Hanny; Torfs, Rudi; Wets, Geert

    2011-07-01

    Time-activity patterns are an important determinant of personal exposure to air pollution. This is demonstrated by measuring personal exposure of 16 participants for 7 consecutive days: 8 couples of which one person was a full-time worker and the other was a homemaker; both had a very different time-activity pattern. We used portable aethalometers to measure black carbon levels with a high temporal resolution and a PDA with GPS-logger and electronic diary. The exposure to black carbon differs between partners by up to 30%, although they live at the same location. The activity contributing most to this difference is transport: Average exposure in transport is 6445 ng m -3, followed by exposure during shopping (2584 ng m -3). Average exposure is lowest while sleeping (1153 ng m -3) and when doing home-based activities (1223 ng m -3). Full-time workers spend almost twice as much time in transport as the homemakers. As a result of the study design we measured in several different homes, shops, cars, etc. enabling a better insight in true overall exposure in those microenvironments. Other factors influencing personal exposure are: background concentrations and location of residence in an urban, suburban or rural environment.

  15. Highly efficient antibacterial iron oxide@carbon nanochains from wüstite precursor nanoparticles.

    Science.gov (United States)

    Situ, Shu F; Samia, Anna Cristina S

    2014-11-26

    A new hydrothermal synthesis approach involving the carbonization of glucose in the presence of wüstite (FeO) nanoparticles is presented, which leads to the fabrication of rapidly acting and potent antibacterial agents based on iron oxide@carbon (IO@C) nanochains. By using nonmagnetic FeO precursor nanoparticles that slowly oxidize into the magnetic Fe3O4 crystal structure under hydrothermal conditions, we were able to prepare well-defined and short-length IO@C nanochains that are highly dispersed in aqueous media and readily interact with bacterial cells, leading to a complete loss in bacterial cell viability within short incubation times at minimal dosage. The smaller IO@C nanochains synthesized using the FeO precursor nanoparticles can reach above 2-fold enhancement in microbe-killing activity when compared to the larger nanochains fabricated directly from Fe3O4 nanoparticles. In addition, the synthesized IO@C nanochains can be easily isolated using an external magnet and be subsequently recycled to effectively eradicate Escherichia coli cells even after five separate treatment cycles. PMID:25347201

  16. New organometallic salts as precursors for the functionalization of carbon nanotubes with metallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Nunez, G., E-mail: galonso@cnyn.unam.mx; Garza, L. Morales de la; Rogel-Hernandez, E.; Reynoso, E. [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia (Mexico); Licea-Claverie, A.; Felix-Navarro, R. M. [Instituto Tecnologico de Tijuana, Centro de Graduados e Investigacion (Mexico); Berhault, G. [UMR 5256 CNRS-Universite de Lyon, Institut de Recherches sur la Catalyse et l' Environnement de Lyon (France); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados S. C. (Mexico)

    2011-09-15

    New organometallic salts were synthesized in aqueous solution and were used as precursors for the functionalization of carbon nanotubes (CNT) by metallic nanoparticles. The precursors were obtained by reaction between HAuCl{sub 4}, (NH{sub 4}){sub 2}PtCl{sub 6}, (NH{sub 4}){sub 2}PdCl{sub 6}, or (NH{sub 4}){sub 3}RhCl{sub 6} with cetyltrimethylammonium bromide (CTAB). The as-obtained (CTA){sub n}Me{sub x}Cl{sub y} salts (with Me = Au, Pt, Pd, Rh) were characterized by Fourier-transform infra-red (FTIR) spectroscopy, {sup 1}H nuclear magnetic resonance (NMR) spectroscopy, and thermogravimetric analysis. These precursors were then used to synthesize metallic nanoparticles of Au, Pt, Pd, and Rh over multiwalled carbon nanotubes (MWCNT). Characterization by scanning transmission electron microscopy (STEM) and thermogravimetric analysis under air reveals that the CNT-supported catalysts exhibit high loading and good dispersion of the metallic nanoparticles with small average particle sizes. The present preparation procedure therefore allows obtaining high densities of small metallic nanoparticles at the surface of MWCNT.

  17. Nanoparticles containing allotropes of carbon have genotoxic effects on glioblastoma multiforme cells

    DEFF Research Database (Denmark)

    Hinzmann, Mateusz; Jaworski, Sławomir; Kutwin, Marta;

    2014-01-01

    the U87 cancer cells. However, incubation with pristine graphene and reduced graphene oxide led to a significant decrease in cell viability, whereas incubation with graphene oxide, graphite, and ultradispersed detonation diamond led to a smaller decrease in cell viability. The results of a comet assay...... demonstrated that pristine graphene, reduced graphene oxide, graphite, and ultradispersed detonation diamond caused DNA damage and were therefore genotoxic in U87 cells, whereas graphene oxide was not. © 2014 Hinzmann et al.......The carbon-based nanomaterial family consists of nanoparticles containing allotropes of carbon, which may have a number of interactions with biological systems. The objective of this study was to evaluate the toxicity of nanoparticles comprised evaluation of cell morphology, and assessment of cell...

  18. Superparamagnetic properties of carbon nanotubes filled with NiFe2O4 nanoparticles

    International Nuclear Information System (INIS)

    Multi walled carbon nanotubes (MWCNTs) were successfully synthesized using custom-made 80 nm pore-size alumina templates, and were uniformly filled with nickel ferrite (NFO) nanoparticles of 7.4 ± 1.7 nm diameter using a novel magnetically assisted capillary action method. X-ray diffraction confirmed the inverse spinel phase for the synthesized NFO. Transmission electron microscopy confirms spherical NFO nanoparticles with an average diameter of 7.4 nm inside MWCNTs. Magnetometry indicates that both NFO and NFO-filled MWCNTs present a blocking temperature around 52 K, with similar superparamagnetic-like behavior, and weak dipolar interactions, giving rise to a super-spin-glass-like behavior at low temperatures. These properties along with the uniformity of sub-100 nm structures and the possibility of tunable magnetic response in variable diameter carbon nanotubes make them ideal for advanced biomedical and microwave applications

  19. A transparent hybrid of nanocrystalline cellulose and amorphous calcium carbonate nanoparticles

    Science.gov (United States)

    Gebauer, Denis; Oliynyk, Vitaliy; Salajkova, Michaela; Sort, Jordi; Zhou, Qi; Bergström, Lennart; Salazar-Alvarez, German

    2011-09-01

    Nanocellulose hybrids are promising candidates for biodegradable multifunctional materials. Hybrids of nanocrystalline cellulose (NCC) and amorphous calcium carbonate (ACC) nanoparticles were obtained through a facile chemical approach over a wide range of compositions. Controlling the interactions between NCC and ACC results in hard, transparent structures with tunable composition, homogeneity and anisotropy.Nanocellulose hybrids are promising candidates for biodegradable multifunctional materials. Hybrids of nanocrystalline cellulose (NCC) and amorphous calcium carbonate (ACC) nanoparticles were obtained through a facile chemical approach over a wide range of compositions. Controlling the interactions between NCC and ACC results in hard, transparent structures with tunable composition, homogeneity and anisotropy. Electronic supplementary information (ESI) available: Additional experimental procedures and results. See DOI: 10.1039/c1nr10681c

  20. Mechanical and microstructural characterization of aluminum reinforced with carbon-coated silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico)]. E-mail: roberto.martinez@cimav.edu.mx; Reyes-Gasga, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico, D.F. (Mexico); Caudillo, R. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States); Garcia-Gutierrez, D.I. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States); Marquez-Lucero, A. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Estrada-Guel, I. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Mendoza-Ruiz, D.C. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Jose Yacaman, M. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States)

    2007-07-12

    Composites of pure aluminum with carbon-coated silver nanoparticles (Ag-C NP) of 10 nm in size were prepared by the mechanical milling process. Transmission electron microscopy showed that the Ag-C NP are homogeneously dispersed into the Al matrix, silver nanoparticles do not coalesce, grow or dissolve in the aluminum matrix due the carbon shell. The values of yield strength ({sigma} {sub y}), maximum strength ({sigma} {sub max}) and micro-hardness Vickers (HVN) of the composites were evaluated and reported as a function of Ag-C NP content. It has been found that the introduction of this type of particles in aluminum strengthen it, increasing all the previous parameters.

  1. Easy synthesis and imaging applications of cross-linked green fluorescent hollow carbon nanoparticles.

    Science.gov (United States)

    Fang, Youxing; Guo, Shaojun; Li, Dan; Zhu, Chengzhou; Ren, Wen; Dong, Shaojun; Wang, Erkang

    2012-01-24

    We propose an ingenious method for synthesizing cross-linked hollow fluorescent carbon nanoparticles (HFCNs) with green emission by simply mixing acetic acid, water, and diphosphorus pentoxide. This is an automatic method without external heat treatment to rapidly produce large quantities of HFCNs, in contrast to other syntheses of fluorescent carbon nanoparticles that required high temperature, complicated operations, or long reaction times. Characterizations of HFCNs through high-resolution transmission electron microscopy, infrared/Raman spectroscopy, and X-ray diffraction indicate that abundant small oxygenous graphite domains existed and endowed the HFCNs with fluorescent properties. After simple post-treatments, the cross-linked HFCNs can be used for cell-imaging applications. Compared with traditional dyes and CdTe quantum dots, HFCNs are the superior fluorescent bioimaging agent according to their low toxicity, stability, and resistance to photobleaching. The HFCNs were also applied to watermark ink and fluorescent powder, showing their promising potentials for further wide usage. PMID:22188541

  2. Polyethyleneimine-modified calcium carbonate nanoparticles for p53 gene delivery.

    Science.gov (United States)

    Chen, Cen; Han, Huafeng; Yang, Wei; Ren, Xiaoyuan; Kong, Xiangdong

    2016-03-01

    In this study, calcium carbonate (CaCO3) nanoparticles with spherical structure were regulated by arginine and successfully synthesized via a facile co-precipitation method. The average particle size of as-prepared CaCO3 was about 900 nm. The properties of nanostructured CaCO3 particles were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction and size distribution. After modified with polyethyleneimine (PEI), the ability of PEI-CaCO3 nanoparticles to carry GFP-marked p53 gene (pEGFP-C1-p53) into cancer cells to express P53 protein were studied. Meanwhile, the cytotoxicity, transfection efficiency, cells growth inhibition and the ability to induce apoptosis by expressed P53 protein were conducted to evaluate the performances of PEI-CaCO3 nanoparticles. The results show that prepared PEI-CaCO3 nanoparticles had good biocompatibility and low cytotoxicity in a certain concentration range. PEI-CaCO3 effectively transfected pEGFP-C1 gene into epithelial-like cancer cells. And with the expression of GFP-P53 fusion protein, pEGFP-C1-p53-gene-loaded PEI-CaCO3 particles significantly reduced the proliferation of cancer cells. These findings indicate that our PEI-modified CaCO3 nanoparticles are potential to be successfully used as carriers for gene therapy. PMID:26816656

  3. Tribological Properties of WS2 Nanoparticles Lubricants on Aluminum-Silicon Alloy and Carbon Steels

    Directory of Open Access Journals (Sweden)

    Riyadh A. AL-SAMARAI

    2013-06-01

    Full Text Available The rheological properties of nanometric tungsten disulphide (WS2 nanoparticles oil lubricants and its tribological performance with two hypereutectic Al-Si alloy and carbon steel are examined. These two oils are used to reduce wear and friction and to explore the actions via tribological pin-on-disk tests. The pin was made from hypereutectic Al-Si alloy on steel disk, taking into consideration the effect of loads (10, 20, 30 N and different speed (200, 300, 400 rpm. Oils with and without WS2 nanoparticles reveal the loss rate due to friction. The results show that WS2 nanoparticles oil-dispersed lubricants are capable of reducing wear, improved by a mechanism which was characterized not only by the viscosity of the WS2 nanoparticles suspensions but also the promotion of contact’s surface as combined anti-corrosion, as well as effective reduction of friction on the surface film. Therefore, a lubricant added to nanoparticles can protect the piston surface.

  4. Single Nanoparticle Mass Spectrometry as a High Temperature Kinetics Tool: Sublimation, Oxidation, and Emission Spectra of Hot Carbon Nanoparticles.

    Science.gov (United States)

    Howder, Collin R; Long, Bryan A; Gerlich, Dieter; Alley, Rex N; Anderson, Scott L

    2015-12-17

    In single nanoparticle mass spectrometry, individual charged nanoparticles (NPs) are trapped in a quadrupole ion trap and detected optically, allowing their mass, charge, and optical properties to be monitored continuously. Previous experiments of this type probed NPs that were either fluorescent or large enough to detect by light scattering. Alternatively, small NPs can be heated to temperatures where thermally excited emission is strong enough to allow detection, and this approach should provide a new tool for measurements of sublimation and surface reaction kinetics of materials at high temperatures. As an initial test, we report a study of carbon NPs in the 20-50 nm range, heated by 10.6 μm, 532 nm, or 445 nm lasers. The kinetics for sublimation and oxidation of individual carbon NPs were studied, and a model is presented for the factors that control the NP temperature, including laser heating, and cooling by sublimation, buffer gas collisions, and radiation. The estimated NP temperatures were in the 1700-2000 K range, and the NP absorption cross sections ranged from ∼0.8 to 0.2% of the geometric cross sections for 532 nm and 10.6 μm excitation, respectively. Emission spectra of single NPs and small NP ensembles show a feature in the IR that appears to be the high energy tail of the thermal (blackbody-like) emission expected from hot particles but also a discrete feature peaking around 750 nm. Both the IR tail and 750 nm peak are observed for all particles and for both IR and visible laser excitation. No significant difference was observed between graphite and amorphous carbon NPs. PMID:26513667

  5. Personal carbon monoxide exposure in five European cities and its determinants

    International Nuclear Information System (INIS)

    Studies involving carbon monoxide (CO) exposure assessment are mainly based on measurements at outdoor fixed sites or in various indoor micro-environments. Few studies have been based on personal exposure measurements. In this paper, we report results on personal measurements of CO in five European cities and we investigate determinants which may influence this personal exposure. Within the multi-centre European EXPOLIS study, personal exposure to CO, measured every minute for 48h, of 401 randomly selected study participants (mainly non-smokers) was monitored in Athens, Basle, Helsinki, Milan and Prague. Each participant also completed a time-microenvironment-activity diary and an extended questionnaire. In addition, for the same time period, ambient levels of CO from fixed site stations were collected. There are significant differences in both personal exposure and ambient levels within the five cities, ranging from high values in Milan and Athens to low in Helsinki. Ambient levels are a significant correlate and determinant of CO 48-h personal exposure in all cities. From the other determinants studied (time spent in street traffic, time of exposure to ETS and time of exposure to gas burning devices) none was consistently significant for all cities. Change of the ambient CO levels from the 25th to the 75th percentile of its distribution resulted in a 1.5-2 fold increase of 48-h personal exposure. Short time personal exposure was also studied in order to assess the influence of specific sources. Exposure levels were significantly higher when participants were in street traffic and in indoor locations in the presence of smokers. Personal 48-h exposure of non-smokers to CO varies among urban populations depending primarily on the ambient levels. For a CO source to be a significant determinant of the personal 48-h CO exposure, it has to affect the levels of CO in the person's proximity for an adequate length of time. Activities of individuals affect shorter term

  6. Influence of Silver nanoparticles on nutrient removal and microbial communities in SBR process after long-term exposure.

    Science.gov (United States)

    Zhang, Zhaohan; Gao, Peng; Li, Moqing; Cheng, Jiaqi; Liu, Wei; Feng, Yujie

    2016-11-01

    The widespread utilization of silver nanoparticles (AgNPs) in industrial and commercial products inevitably raises the release into wastewater that might cause potential negative impacts on sewage treatment system. In this paper, long-term exposure experiments at four levels were conducted to determine whether AgNPs caused adverse impacts on nutrient removals in sequencing batch reactors (SBRs) and changes of microbial community structure. Compared with the control reactor (without AgNPs), carbon, nitrogen and phosphorus removal in presence of 0.1mg/L AgNPs was no difference. However, presence of 1.0 and 10mg/L AgNPs decreased the average removal efficiencies of COD from 95.4% to 85.2% and 68.3%, ammonia nitrogen from 98.8% to 71.2% and 49%, SOP from 97.6% to 75.5% and 54.1%, respectively. It was found that AgNPs could accumulate in sludge with the distribution coefficients of 39.2-114L/g, inhibit the protein and polysaccharide production in EPS, reduce the SOUR of sludge, and greatly increase LDH release from microbial cells. The illumina high-throughput sequencing results indicated that AgNPs concentration changed the structures of bacterial communities, associating with the effects of AgNPs on reactor performance. Sequence analyses showed that Proteobacteria, Bacteroidetes and Acidobacteria were the dominant phyla. It was notable that AgNPs addition reduced the contents of several nitrifying bacteria at genera level in sludge, leading to the lower removal of nitrogen. PMID:27343942

  7. Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide)/ Carbon Fiber Laminates: Thermomechanical Behaviour

    OpenAIRE

    Díez-Pascual, Ana M.; Mohammed Naffakh

    2013-01-01

    Carbon fiber (CF)-reinforced high-temperature thermoplastics such as poly(phenylene sulphide) (PPS) are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS2) lubricant nanoparticles were used to manufacture PPS/IF-WS2/CF lamin...

  8. A Novel Cholesterol Oxidase Biosensor Based on Pt-nanoparticle /Carbon Nanotube Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    Qiao Cui SHI; Tu Zhi PENG

    2005-01-01

    A Pt-nanoparticle/carbon nanotube modified graphite electrode immobilized with cholesterol oxidase/sol-gel layer was developed for monitoring cholesterol. Using this electrode,cholesterol concentration (4.0×10-6 to 1.0×10 mol/L) could be determined accurately in the presence of ascorbic or uric acid, and the response time was rapid (< 20 s). This biosensor has high sensitivity and selectivity.

  9. Determination of thiourea using a carbon paste electrode decorated with copper oxide nanoparticles

    International Nuclear Information System (INIS)

    We report on a novel sensor for the electrochemical determination of thiourea (TU). It is based on an active carbon paste electrode modified with copper oxide nanoparticles. The modified electrode and the electrochemical properties of thiourea on its surface were investigated using cyclic voltammetry and differential pulse voltammetry. Under optimized conditions, the detection limit is 20 μg L−1 of TU. The method was applied to the determination of thiourea in fruit juice, orange peel and industrial waste water. (author)

  10. Pt nanoparticles incorporated into phosphorus-doped ordered mesoporous carbons: enhanced catalytic activity for methanol electrooxidation

    International Nuclear Information System (INIS)

    Graphical abstract: Pt nanoparticles are supported on the phosphorus-doped ordered mesoporous carbons (Pt/POMCs), which show much improved electrocatalytic activity, CO-tolerance and long-term stability toward methanol oxidation. - Highlights: • P-doped ordered mesoporous carbons (POMCs) as support for Pt nanoparticles. • The addition of P promote the formation of oxygen-containing functional groups. • The P-doped OMCs demonstrate excellent CO-tolerance towards MOR. • Pt/P7OMCs shows much enhanced electrochemical activity and long-term stability. - Abstract: Phosphorus-doped ordered mesoporous carbons (POMCs) with different P content are successfully synthesized by hard template method using SBA-15 as hard template, sucrose as carbon precursor and triphenylphosphane as phosphorus precursor. Pt nanoparticles with size of 3.5 ± 0.4 nm are deposited on the framework of POMCs. The doping of P into OMCs facilitates the dispersion of Pt nanoparticles and accelerates the formation of oxygen-containing functional groups. Pt/POMCs nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption–desorption and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry and chronoamperometry studies exhibit that the Pt/POMCs, especially Pt/P7OMCs, have larger electrochemical active surface area (ECSA), higher electrocatalytic activity, more negative onset potential and long-time stability for the electrooxidation toward methanol than that of Pt/OMCs, PtRu/XC and commercial Pt/C catalysts. These enhanced performances indicate that Pt/P7OMCs catalyst may be an excellent anode catalyst for direct methanol fuel cell (DMFC)

  11. Methanol Electro-Oxidation on Pt-Ru Alloy Nanoparticles Supported on Carbon Nanotubes

    OpenAIRE

    Yangchuan Xing; Liang Li

    2009-01-01

    Carbon nanotubes (CNTs) have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved catalyst activities were observed and attributed to metal-support interactions. We report a study on the kinetics of methanol electro-oxidation on CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt 53 Ru 47 /CNT, Pt 69 Ru 31 /CNT and Pt 77 Ru 23 /CNT, were prepared and investigated in detail. Experiments were conducted at ...

  12. Toxicity assessment of TiO{sub 2} nanoparticles in zebrafish embryos under different exposure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Clemente, Z., E-mail: zairaclemente@yahoo.com.br [Laboratório de Ecotoxicologia e Biossegurança, Embrapa CNPMA, Jaguariúna, SP (Brazil); Programa de Pós-graduação em Biologia Funcional e Molecular, UNICAMP, Campinas, SP (Brazil); Castro, V.L.S.S. [Laboratório de Ecotoxicologia e Biossegurança, Embrapa CNPMA, Jaguariúna, SP (Brazil); Moura, M.A.M. [Laboratório da Ciência das Plantas Daninhas, Instituto Biológico, APTA/SAA, Campinas, SP (Brazil); Jonsson, C.M. [Laboratório de Ecotoxicologia e Biossegurança, Embrapa CNPMA, Jaguariúna, SP (Brazil); Fraceto, L.F. [Programa de Pós-graduação em Biologia Funcional e Molecular, UNICAMP, Campinas, SP (Brazil); Departamento de Engenharia Ambiental, UNESP, Sorocaba, SP (Brazil)

    2014-02-15

    Highlights: •Nano-TiO{sub 2} accelerated hatching of the larvae. •Exposure to anatase/rutile mixture under UV light altered the equilibrium and survival of the larvae. •Nano-TiO{sub 2} caused alterations in the activities of CAT and GST. -- Abstract: The popularity of TiO{sub 2} nanoparticles (nano-TiO{sub 2}) lies in their wide range of nanotechnological applications, together with low toxicity. Meanwhile, recent studies have shown that the photocatalytic properties of this material can result in alterations in their behavior in the environment, causing effects that have not yet been fully elucidated. The objective of this study was to evaluate the toxicity of two formulations of nano-TiO{sub 2} under different illumination conditions, using an experimental model coherent with the principle of the three Rs of alternative animal experimentation (reduction, refinement, and replacement). Embryos of the fish Danio rerio were exposed for 96 h to different concentrations of nano-TiO{sub 2} in the form of anatase (TA) or an anatase/rutile mixture (TM), under either visible light or a combination of visible and ultraviolet light (UV). The acute toxicity and sublethal parameters evaluated included survival rates, malformation, hatching, equilibrium, and overall length of the larvae, together with biochemical biomarkers (specific activities of catalase (CAT), glutathione S-transferase (GST), and acid phosphatase (AP)). Both TA and TM caused accelerated hatching of the larvae. Under UV irradiation, there was greater mortality of the larvae of the groups exposed to TM, compared to those exposed to TA. Exposure to TM under UV irradiation altered the equilibrium of the larvae. Alterations in the activities of CAT and GST were indicative of oxidative stress, although no clear dose-response relationship was observed. The effects of nano-TiO{sub 2} appeared to depend on both the type of formulation and the illumination condition. The findings contribute to elucidation of the

  13. The influence of roadside vegetation barriers on airborne nanoparticles and pedestrians exposure under varying wind conditions

    Science.gov (United States)

    Al-Dabbous, Abdullah N.; Kumar, Prashant

    2014-06-01

    Roadside vegetation barriers are used in many urban areas to restrict air and noise pollution from reaching roadside pedestrians, but their effectiveness in limiting the movement of nanoparticles is not yet known. This study investigates the influence of a roadside vegetation barrier on particle number distribution (PND) and concentration (PNC) and associated exposure under different wind directions. Size-resolved particles in the 5-560 nm size range were measured along a busy roadside in Guildford (Surrey, UK) using a fast response differential mobility spectrometer (DMS50). A custom-built solenoid switching system, together with the DMS50, was used to make sequential measurements at the front (L2), middle (L3) and back (L4) of the vegetation barrier; L1 was in parallel to L2 at a vegetation-free location. Measured data were divided into the three predominant wind directions: cross-road (NW-SW), cross-footpath (NE-SE) and along-road (NW-NE). The consistency in the shape of PNDs and the corresponding geometric mean diameters at the three sites (L2, L3, L4) indicate an identical removal effect of vegetation barrier for all sizes of particles. Comparison of the PNCs at two parallel locations (with and without the vegetation barrier) showed ˜11% higher PNCs (1.99 ± 1.77 × 105 cm-3) at L2 than those at L1 during cross-road winds, showing the impeding effect of the vegetation barrier. Such differences were insignificant during the remaining wind directions. Cross-road winds indicate the effect of vegetation barrier; the PNCs were decreased by 14 and 37% at L3 and L4, respectively, compared with L2. During cross-footpath winds, particles were carried away by the wind from the sampling location. Significant decrease in PNCs were consequently seen at L3 (1.80 ± 1.01 × 104 cm-3) and L4 (1.49 ± 0.91 × 104 cm-3) compared with L2 (6.26 ± 3.31 × 104 cm-3). The PNCs at these locations showed modest differences during the cross-footpath and along-road winds. Respiratory

  14. Toxicity assessment of TiO2 nanoparticles in zebrafish embryos under different exposure conditions

    International Nuclear Information System (INIS)

    Highlights: •Nano-TiO2 accelerated hatching of the larvae. •Exposure to anatase/rutile mixture under UV light altered the equilibrium and survival of the larvae. •Nano-TiO2 caused alterations in the activities of CAT and GST. -- Abstract: The popularity of TiO2 nanoparticles (nano-TiO2) lies in their wide range of nanotechnological applications, together with low toxicity. Meanwhile, recent studies have shown that the photocatalytic properties of this material can result in alterations in their behavior in the environment, causing effects that have not yet been fully elucidated. The objective of this study was to evaluate the toxicity of two formulations of nano-TiO2 under different illumination conditions, using an experimental model coherent with the principle of the three Rs of alternative animal experimentation (reduction, refinement, and replacement). Embryos of the fish Danio rerio were exposed for 96 h to different concentrations of nano-TiO2 in the form of anatase (TA) or an anatase/rutile mixture (TM), under either visible light or a combination of visible and ultraviolet light (UV). The acute toxicity and sublethal parameters evaluated included survival rates, malformation, hatching, equilibrium, and overall length of the larvae, together with biochemical biomarkers (specific activities of catalase (CAT), glutathione S-transferase (GST), and acid phosphatase (AP)). Both TA and TM caused accelerated hatching of the larvae. Under UV irradiation, there was greater mortality of the larvae of the groups exposed to TM, compared to those exposed to TA. Exposure to TM under UV irradiation altered the equilibrium of the larvae. Alterations in the activities of CAT and GST were indicative of oxidative stress, although no clear dose-response relationship was observed. The effects of nano-TiO2 appeared to depend on both the type of formulation and the illumination condition. The findings contribute to elucidation of the factors involved in the toxicity of these

  15. Surface decoration of amine-rich carbon nitride with iron nanoparticles for arsenite (As(III)) uptake: The evolution of the Fe-phases under ambient conditions.

    Science.gov (United States)

    Georgiou, Y; Mouzourakis, E; Bourlinos, A B; Zboril, R; Karakassides, M A; Douvalis, A P; Bakas, Th; Deligiannakis, Y

    2016-07-15

    A novel hybrid material (gC3N4-rFe) consisting of amine-rich graphitic carbon nitride (gC3N4), decorated with reduced iron nanoparticles (rFe) is presented. XRD and TEM show that gC3N4-rFe bears aggregation-free Fe-nanoparticles (10nm) uniformly dispersed over the gC3N4 surface. In contrast, non-supported iron nanoparticles are strongly aggregated, with non-uniform size distribution (20-100nm). (57)Fe-Mössbauer spectroscopy, dual-mode electron paramagnetic resonance (EPR) and magnetization measurements, allow a detailed mapping of the evolution of the Fe-phases after exposure to ambient O2. The as-prepared gC3N4-rFe bears Fe(2+) and Fe° phases, however only after long exposure to ambient O2, a Fe-oxide layer is formed around the Fe° core. In this [Fe°/Fe-oxide] core-shell configuration, the gC3N4-rFe hybrid shows enhanced As(III) uptake capacity of 76.5mgg(-1), i.e., ca 90% higher than the unmodified carbonaceous support, and 300% higher than the non-supported Fe-nanoparticles. gC3N4-rFe is a superior As(III) sorbent i.e., compared to its single counterparts or vs. graphite/graphite oxide or activated carbon analogues (11-36mgg(-1)). The present results demonstrate that the gC3N4 matrix is not simply a net that holds the particles, but rather an active component that determines particle formation dynamics and ultimately their redox profile, size and surface dispersion homogeneity. PMID:27037479

  16. NiCu Alloy Nanoparticle-Loaded Carbon Nanofibers for Phenolic Biosensor Applications

    OpenAIRE

    Dawei Li; Pengfei Lv; Jiadeng Zhu; Yao Lu; Chen Chen; Xiangwu Zhang; Qufu Wei

    2015-01-01

    NiCu alloy nanoparticle-loaded carbon nanofibers (NiCuCNFs) were fabricated by a combination of electrospinning and carbonization methods. A series of characterizations, including SEM, TEM and XRD, were employed to study the NiCuCNFs. The as-prepared NiCuCNFs were then mixed with laccase (Lac) and Nafion to form a novel biosensor. NiCuCNFs successfully achieved the direct electron transfer of Lac. Cyclic voltammetry and linear sweep voltammetry were used to study the electrochemical propertie...

  17. Safe recycling of materials containing persistent inorganic and carbon nanoparticles

    NARCIS (Netherlands)

    L. Reijnders

    2014-01-01

    For persistent inorganic and carbon nanomaterials, considerable scope exists for a form of recycling called ‘resource cascading’. Resource cascading is aimed at the maximum exploitation of quality and service time of natural resources. Options for resource cascading include engineered nanomaterials

  18. Single-step synthesis of nanocomposite of copper and carbon nanoparticles using arc discharge in liquid nitrogen

    International Nuclear Information System (INIS)

    A new strategy for single-step synthesis of copper and carbon nanoparticle composite by arc discharge in liquid nitrogen was proposed. The synthesized products consist of carbon nanoparticles (CNPs) which include multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanohorns (SWCNHs) and multi-shelled carbon nanocapsules (MSCNCs) containing Cu clusters inside. Evidence of transmission electron microscopic analyses reveal that under with arc current of 180 A arc discharge between copper and graphite electrodes in liquid nitrogen could provide MSCNCs with narrow size distribution in a range of 70-150 nm. Meanwhile, MWCNTs with diameter of 20-40 nm and length of 150-350 nm became selectively synthesized under the condition of discharge in liquid nitrogen with arc current of 100 A. Spectroscopic analyses confirm that copper nanoparticles are cuprite while BET analyses also reveal that the synthesized nanocomposite possess acceptably high specific surface area.

  19. Gold nanoparticles grown inside carbon nanotubes: synthesis and electrical transport measurements

    Science.gov (United States)

    2014-01-01

    The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a ‘non-metallic’ temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres. PMID:24910571

  20. Particle size and crystallographic orientation controlled electrodeposition of platinum nanoparticles on carbon nanotubes

    International Nuclear Information System (INIS)

    Highlights: • Particle size controlled electrodeposition of platinum on carbon nanotubes. • Control on crystallographic orientation of platinum surface is demonstrated. • Catalytic activity shows considerable dependence on crystallographic orientation. - Abstract: Platinum-coated carbon nanotubes (Pt/CNTs) with desired particle size and preferred surface crystallographic orientations have a variety of applications in diverse fields. Pt/CNTs having uniform dispersion of Pt nanoparticles are synthesized via electrodeposition route using CNT coated carbon fiber as the working electrode and H2PtCl6.6H2O as Pt precursor. Particle size and crystallographic orientation of Pt nanoparticles are controlled by using polyvinylpyrrolidone (PVP) as the protecting agent during electrodeposition in H2SO4 or HCl containing coating baths. Cyclic voltammetric study and X-ray diffraction analysis suggest Pt(100) surface enrichment of Pt nanoparticles in presence of PVP, which increases with increasing PVP concentration. Although the Pt deposition rate decreases significantly in presence of Cl− ions, the enrichment effect is observed both in the H2SO4 as well as the HCl containing baths. The Pt/CNT synthesized in presence of PVP exhibit higher oxygen reduction reaction activity (acidic media) and methanol oxidation activity compared to that synthesized without PVP. The process may be utilized to synthesize Pt based electrocatalysts with controlled particle size and preferred surface orientation

  1. Dechlorination of Environmental Contaminants Using a Hybrid Nanocatalyst: Palladium Nanoparticles Supported on Hierarchical Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Hema Vijwani

    2012-01-01

    Full Text Available This paper demonstrates the effectiveness of a new type of hybrid nanocatalyst material that combines the high surface area of nanoparticles and nanotubes with the structural robustness and ease of handling larger supports. The hybrid material is made by fabricating palladium nanoparticles on two types of carbon supports: as-received microcellular foam (Foam and foam with carbon nanotubes anchored on the pore walls (CNT/Foam. Catalytic reductive dechlorination of carbon tetrachloride with these materials has been investigated using gas chromatography. It is seen that while both palladium-functionalized carbon supports are highly effective in the degradation of carbon tetrachloride, the rate of degradation is significantly increased with palladium on CNT/Foam. However, there is scope to increase this rate further if the wettability of these structures can be enhanced in the future. Microstructural and spectroscopic analyses of the fresh and used catalysts have been compared which indicates that there is no change in density or surface chemical states of the catalyst after prolonged use in dechlorination test. This implies that these materials can be used repeatedly and hence provide a simple, powerful, and cost-effective approach for dechlorination of water.

  2. Carbon coating may expedite the fracture of carbon-coated silicon core-shell nanoparticles during lithiation

    Science.gov (United States)

    Li, Weiqun; Cao, Ke; Wang, Hongtao; Liu, Jiabin; Zhou, Limin; Yao, Haimin

    2016-02-01

    Previous studies on silicon (Si) indicate that lithiation-induced fracture of crystalline Si nanoparticles can be greatly inhibited if their diameter is reduced to below a critical scale of around 150 nm. In this paper, in situ lithiation of individual carbon-coated Si nanoparticles (Si@C NPs) is conducted which shows that Si@C NPs will fracture during lithiation even though their diameter is much smaller than 150 nm, implying a deleterious effect of the carbon coating on the integrity of the Si@C NPs during lithiation. To shed light on this effect, finite element analysis is carried out which reveals that the carbon coating, if fractured during lithiation, will induce cracks terminating at the C/Si interface. Such cracks, upon further lithiation, can immediately propagate into the Si core due to the elevated driving force caused by material inhomogeneity between the coating and core. To prevent the fracture of the carbon coating so as to protect the Si core, a design guideline is proposed by controlling the ratio between the diameter of Si core and the thickness of carbon coating. The results in this paper should be of practical value to the design and application of Si-based core-shell structured anode materials for lithium ion batteries.Previous studies on silicon (Si) indicate that lithiation-induced fracture of crystalline Si nanoparticles can be greatly inhibited if their diameter is reduced to below a critical scale of around 150 nm. In this paper, in situ lithiation of individual carbon-coated Si nanoparticles (Si@C NPs) is conducted which shows that Si@C NPs will fracture during lithiation even though their diameter is much smaller than 150 nm, implying a deleterious effect of the carbon coating on the integrity of the Si@C NPs during lithiation. To shed light on this effect, finite element analysis is carried out which reveals that the carbon coating, if fractured during lithiation, will induce cracks terminating at the C/Si interface. Such cracks, upon

  3. Preparation of carbon-coated copper nanoparticles by detonation decomposition of copper ion doped sol–gel explosive precursors

    International Nuclear Information System (INIS)

    Carbon-coated copper (Cu-C) nanoparticles with a core–shell structure were prepared by detonation decomposition of energetic Cu ion doped sol–gel explosive precursors. The composite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high resolution TEM, energy dispersive X-ray spectroscopy, and Raman spectroscopy, respectively. The results indicate that the as-obtained core–shell structure Cu-C nanoparticles are with diameter about 10–40 nm. The composite nanoparticles are composed of face-centered cubic-Cu and the amorphous/graphitic carbon coating shells. The thermal stability of the obtained samples was studied by a difference scanning calorimetry–thermogravimetric analyzer. By varying the composition of initial mixtures that contain Cu ion explosive precursors, the different size and chemical composition of composite nanoparticles are shown in this study. The growth mechanism of Cu-C was also briefly discussed.

  4. Carbon-coated SnSb nanoparticles dispersed in reticular structured nanofibers for lithium-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Xiao [College of Textiles and Clothing, Xin Jiang University, Xinjiang, Urumqi 830046 (China); Key Laboratory of Textile Science and Technology, Donghua University, Ministry of Education, Shanghai 201620 (China); Zhou, Huimin; Li, Zhiyong; Shan, Xiaohong [College of Textiles and Clothing, Xin Jiang University, Xinjiang, Urumqi 830046 (China); Xia, Xin, E-mail: xjxiaxin@163.com [College of Textiles and Clothing, Xin Jiang University, Xinjiang, Urumqi 830046 (China); Key Laboratory of Textile Science and Technology, Donghua University, Ministry of Education, Shanghai 201620 (China)

    2015-01-25

    Highlights: • Sn{sub 0.92}Sb{sub 0.08}O{sub 2.04} nanoparticles as SnSb alloy precursor. • Carbon-coated SnSb nanoparticles were prepared and then embedded in carbon nanofibers. • The synergic effect of carbon coating and special structure improved cycling stability. - Abstract: Carbon coating and carbon nanofiber processes were used to enhance the cycling performance of SnSb alloys. Carbon-coated SnSb alloys were firstly prepared by a simple hydrothermal method to build the first protection, and then carbon-coated SnSb nanoparticles were embedded in carbon nanofibers via single-spinneret electrospinning followed by carbonization. The crystal structure of carbon-coated SnSb/C hybrid nanofibers was characterized by X-ray diffraction (XRD). The morphologies of carbon-coated SnSb alloys and hybrid nanofibers were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. The thermal stability of hybrid nanofibers were determined by thermogravimetric analysis (TGA). The electrochemical properties were investigated as a potential high-capacity anode material for lithium-ion batteries. The results showed that the hybrid nanofibers exhibited excellent electrochemical performance due to the special structure. The carbon shell can effectively hinder the agglomeration of SnSb alloys, while maintaining electronic conduction as well as accommodating drastic volume changes during lithium insertion and extraction and carbon nanofibers formed a further protection. The resultant carbon-coated SnSb nanoparticles dispersed in carbon nanofibers deliver a high capacity of 674 mA h g{sup −1} and a good capacity retention of 68.7% after 50 cycles.

  5. Carbon-coated SnSb nanoparticles dispersed in reticular structured nanofibers for lithium-ion battery anodes

    International Nuclear Information System (INIS)

    Highlights: • Sn0.92Sb0.08O2.04 nanoparticles as SnSb alloy precursor. • Carbon-coated SnSb nanoparticles were prepared and then embedded in carbon nanofibers. • The synergic effect of carbon coating and special structure improved cycling stability. - Abstract: Carbon coating and carbon nanofiber processes were used to enhance the cycling performance of SnSb alloys. Carbon-coated SnSb alloys were firstly prepared by a simple hydrothermal method to build the first protection, and then carbon-coated SnSb nanoparticles were embedded in carbon nanofibers via single-spinneret electrospinning followed by carbonization. The crystal structure of carbon-coated SnSb/C hybrid nanofibers was characterized by X-ray diffraction (XRD). The morphologies of carbon-coated SnSb alloys and hybrid nanofibers were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. The thermal stability of hybrid nanofibers were determined by thermogravimetric analysis (TGA). The electrochemical properties were investigated as a potential high-capacity anode material for lithium-ion batteries. The results showed that the hybrid nanofibers exhibited excellent electrochemical performance due to the special structure. The carbon shell can effectively hinder the agglomeration of SnSb alloys, while maintaining electronic conduction as well as accommodating drastic volume changes during lithium insertion and extraction and carbon nanofibers formed a further protection. The resultant carbon-coated SnSb nanoparticles dispersed in carbon nanofibers deliver a high capacity of 674 mA h g−1 and a good capacity retention of 68.7% after 50 cycles

  6. Impacts of hematite nanoparticle exposure on biomechanical, adhesive, and surface electrical properties of Escherichia coli cells.

    Science.gov (United States)

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-06-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomaterials. Both scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that E. coli cells had noticeable deformation with hematite treatment for 45 min with a statistical significance. The hematite-treated cells became significantly harder or stiffer than untreated ones, as evidenced by indentation and spring constant measurements. The average indentation of the hematite-treated E. coli cells was 120 nm, which is significantly lower (P hematite-treated E. coli cells (0.28 ± 0.11 nN/nm) was about 20 times higher than that of untreated ones (0.01 ± 0.01 nN/nm). The zeta potential of E. coli cells, measured by dynamic light scattering (DLS), was shown to shift from -4 ± 2 mV to -27 ± 8 mV with progressive surface adsorption of hematite NPs, a finding which is consistent with the local surface potential measured by Kelvin probe force microscopy (KPFM). Overall, the reported findings quantitatively revealed the adverse impacts of nanomaterial exposure on physical properties of bacterial cells and should provide insight into the toxicity mechanisms of nanomaterials. PMID:22467500

  7. Controlled exposures of volunteers to respirable carbon and sulfuric acid aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, K.R.; Avol, E.L.; Edwards, S.A.; Shamoo, D.A.; Ruchuan Peng; Linn, W.S.; Hackney, J.D. (Univ. of Southern California, Downey (United States))

    1992-06-01

    Respirable carbon or fly ash particles are suspected to increase the respiratory toxicity of coexisting acidic air pollutants, by concentrating acid on their surfaces and so delivering it efficiently to the lower respiratory tract. To investigate this issue, the authors exposed 15 healthy and 15 asthmatic volunteers in a controlled-environment chamber to four test atmospheres: (1) clean air; (2) 0.5-{mu}m H{sub 2}SO{sub 4} aerosol at {approx}100 {mu}g/m{sup 3}, generated from water solution; (3) 0.5-{mu}m carbon aerosol at {approx}250 {mu}g/m{sup 3}, generated from highly pure carbon black with specific surface area comparable to ambient pollution particles; and (4) carbon as in (3) plus {approx}100 {mu}g/m{sup 3} of ultrafine H{sub 2}SO{sub 4} aerosol generated from fuming sulfuric acid. Electron microscopy showed that nearly all acid in (4) became attached to carbon particle surfaces, and that most particles remained in the sub-{mu}m size range. Exposures were performed double-blind, 1 week apart. They lasted 1 hr each, with alternate 10-min periods of heavy exercise (ventilation {approx}50 L/min) and rest. Subjects gargled citrus juice before exposure to suppress airway ammonia. Lung function and symptoms were measured pre-exposure, after initial exercise, and at end-exposure. Bronchial reactivity to methacholine was measured after exposure. Statistical analyses tested for effects of H{sub 2}SO{sub 4} or carbon, separate or interactive, on health measures.

  8. Assessment of specific oxidative stress biomarkers in tissues after the inhalation exposure of mice to CdO nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Bláhová, L.; Podborská, M.; Kohoutek, J.; Lebedová, J.; Bláha, L.; Večeřa, Zbyněk; Buchtová, Marcela; Míšek, Ivan; Hilscherová, K.

    Brno, 2015. s. 34-34. ISBN N. [TOXCON 2015. Mezioborová česko-slovenská toxikologická konference /20./. 27.05.2015-29.05.2015, Brno] R&D Projects: GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:68081715 ; RVO:67985904 Keywords : stress biomarkers * CdO nanoparticles * LC-ESI-MS/MS * inhalation exposure Subject RIV: CB - Analytical Chemistry, Separation; EB - Genetics ; Molecular Biology (UZFG-Y)

  9. Foliar exposure of the crop Lactuca sativa to silver nanoparticles: evidence for internalization and changes in Ag speciation

    OpenAIRE

    Larue, Camille; CASTILLO-MICHEL, H.; Sobanska, S.; CECILLON, Lauric; Bureau, Sarah; Barthes, V.; Ouerdane, L; Carriere, M.; Sarret, G.

    2014-01-01

    The impact of engineered nanomaterials on plants, which act as a major point of entry of contaminants into trophic chains, is little documented. The foliar pathway is even less known than the soil-root pathway. However, significant inputs of nanoparticles (NPs) on plant foliage may be expected due to deposition of atmospheric particles or application of NP-containing pesticides. The uptake of Ag-NPs in the crop species Lactuca sativa after foliar exposure and their possible biotransformation ...

  10. Synthesis of carbon encapsulated SiO2 nanoparticles from rice husk and its application in solar to steam conversion

    Science.gov (United States)

    Mufti, Nandang; Lestari, Nurhayati A.; Suciani, Erlin; Fuad, Abdulloh; Diantoro, Markus

    2016-03-01

    Steam is important in many technological applications including sterilization of medical devices, cleaning, and power generating. In general, steam can be produced by boiling water at high temperature. In new technology, solar can convert water directly into steam even at low temperature by using nanoparticles. In this research we study solar to steam conversion of carbon encapsulated SiO2 nanoparticles (SiO2@C) synthesized from rice husk. SiO2 nanoparticles were synthesized using alkali extraction and sol-gel methods. While synthesis of carbon encapsulated SiO2 nanoparticles was done by sonochemical method with glucose as source of carbon. The samples have been characterized by XRF, SEM-EDX, and XRD. The effectivity of solar steam conversion performed by measuring time dependent of temperature and pressure. XRF and XRD results shown that SiO2 nanoparticles have purity of 97.2% inn amorphous phase. Carbon encapsulated SiO2 nanoparticles (SiO2@C) have successfully synthesized indicating by NaOH base test. The morphology of SiO2@C is agglomerated with average particle size around 20 nm. The measurement of solar to steam conversion showed that increasing carbon concentration of SiO2@C rises steam production with indicated by increasing temperature and pressure of steam.

  11. Carbon encapsulated ultrasmall SnO2 nanoparticles anchoring on graphene/TiO2 nanoscrolls for lithium storage

    International Nuclear Information System (INIS)

    Highlights: • Highly-dispersive ultrasmall SnO2 nanoparticles (4∼8 nm) are anchored on the substrate of graphene/TiO2 nanoscrolls. • The encapsulated glucose-derived carbon layer effectively immobilizes SnO2 nanoparticles. • The enhanced cycling performance is owing to the synergetic effects between the multicomposites. - Abstract: Amorphous carbon is coated on the surface of ultrasmall SnO2 nanoparticles which are anchored on graphene/TiO2 nanoscrolls via hydrothermal treatment, followed by annealing process. Transmission electron microscope images show that ultrasmall SnO2 nanoparticles are anchored on graphene/TiO2 nanoscrolls and further immobilized by the outermost amorphous carbon layer. The carbon encapsulated SnO2@graphene/TiO2 nanocomposites deliver high reversible capacities around 1131, 793, 621 and 476 mAh g−1 at the current densities of 100, 250, 500, and 1000 mA g−1, respectively. It is found that SnO2 nanoparticles play a dominant role in the contributions of reversible capacity according to the cyclic voltammetry curves, voltage-capacity curves and dQ/dV vs. potential curves. The substrate of graphene/TiO2 nanoscrolls provides sufficient transport channels for lithium ions and high electron conductivity. While the outermost amorphous carbon layer prevents the peeling of SnO2 nanoparticles from the substrate, therefore making them desirable alternative anode materials for lithium ion batteries

  12. Different in vitro exposure regimens of murine primary macrophages to silver nanoparticles induce different fates of nanoparticles and different toxicological and functional consequences.

    Science.gov (United States)

    Aude-Garcia, Catherine; Villiers, Florent; Collin-Faure, Véronique; Pernet-Gallay, Karin; Jouneau, Pierre-Henri; Sorieul, Stéphanie; Mure, Geoffrey; Gerdil, Adèle; Herlin-Boime, Nathalie; Carrière, Marie; Rabilloud, Thierry

    2016-06-01

    Silver nanoparticles (Ag-NPs) are used in a variety of consumers' goods. Their toxicological impact is currently intensely studied, mostly upon acute exposure, but their intracellular dissolution and fate is rather poorly documented. In this study, murine primary macrophages were exposed to a single high but non-lethal dose of Ag-NPs or to repeated, low doses of Ag-NPs. Cells were either collected immediately after acute exposure or after 72 h of recovery in the NP-free exposure medium. Ag intracellular content and distribution were analyzed by particle-induced X-ray emission, transmission electron microscopy coupled to energy-dispersive spectroscopy analysis and inductively coupled plasma mass spectrometry. In parallel, macrophage functionality as well as inflammatory and thiol-responses were assessed after Ag-NP exposure. We show that Ag accumulation in macrophages is similar upon acute and repeated exposure to Ag-NPs, and that Ag is partly expelled from cells during the 72 h recovery stage. However, acute exposure leads to a strong response of macrophages, characterized by reduced mitochondrial membrane potential, phagocytic capacity and nitric oxide (NO) production upon lipopolysaccharide (LPS) stimulation. Under this condition, we also show an increased release of proinflammatory cytokines as well as a decreased release of anti-inflammatory cytokines. This response is reversible since these biomarkers reach their basal level after the recovery phase; and is much less intense in repeatedly exposed cells. These results suggest that repeated exposure of macrophages to Ag-NPs, which is a more realistic exposure scenario than acute exposure, leads to significant Ag intracellular accumulation but a much less intense toxicological response. PMID:26554598

  13. Determinations of personal carbon monoxide exposure and blood carboxyhemoglobin levels in Korea.

    Science.gov (United States)

    Chung, Y; Park, S E; Lee, K; Yanagisawa, Y; Spengler, J D

    1994-12-01

    Determinant factors for personal carbon monoxide (CO) exposures were sought in Korea, where CO poisoning has been a major public health problem due to coal briquette (Yeontan) combustion for space heating and cooking. Personal 24-hr CO exposures of 15 housewives were measured by CO passive samplers on 2 days of the week (Wednesday and Sunday). Blood samples were taken to measure carboxyhemoglobin (COHb) just after the exposure sampling. Average CO exposure and COHb level were 5.6 ppm and 2.4%, respectively. Personal CO exposures as well as COHb levels were significantly increased by the use of Yeontan, especially on a weekday. Carboxyhemoglobin levels were closely related to the time between blood collection and replacement of Yeontan: the closer the blood collection was to replace Yeontan, the higher the COHb levels were. Assuming a background COHb of 1.34%, COHb increased on average by 1.8% with a 24-hr personal CO exposure of 10 ppm. The relationship between CO exposure and COHb level was provided by simultaneous direct measurements in real environment, although a measurement of COHb at the end of exposure could not represent previous 24-hr exposure thoroughly. PMID:7871846

  14. Synthesis of TiO2 nanoparticles containing Fe, Si, and V using multiple diffusion flames and catalytic oxidation capability of carbon-coated nanoparticles

    KAUST Repository

    Ismail, Mohamed

    2016-01-19

    Titanium dioxide (TiO2) nanoparticles containing iron, silicon, and vanadium are synthesized using multiple diffusion flames. The growth of carbon-coated (C–TiO2), carbon-coated with iron oxide (Fe/C–TiO2), silica-coated (Si–TiO2), and vanadium-doped (V–TiO2) TiO2 nanoparticles is demonstrated using a single-step process. Hydrogen, oxygen, and argon are utilized to establish the flame, with titanium tetraisopropoxide (TTIP) as the precursor for TiO2. For the growth of Fe/C–TiO2 nanoparticles, TTIP is mixed with xylene and ferrocene. While for the growth of Si–TiO2 and V–TiO2, TTIP is mixed with hexamethyldisiloxane (HMDSO) and vanadium (V) oxytriisopropoxide, respectively. The synthesized nanoparticles are characterized using high-resolution transmission electron microscopy (HRTEM) with energy-filtered TEM for elemental mapping (of Si, C, O, and Ti), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption BET surface area analysis, and thermogravimetric analysis. Anatase is the dominant phase for the C–TiO2, Fe/C–TiO2, and Si–TiO2 nanoparticles, whereas rutile is the dominant phase for the V–TiO2 nanoparticles. For C–TiO2 and Fe/C–TiO2, the nanoparticles are coated with about 3-5-nm thickness of carbon. The iron-based TiO2 nanoparticles significantly improve the catalytic oxidation of carbon, where complete oxidation of carbon occurs at a temperature of 470 °C (with iron) compared to 610 °C (without iron). Enhanced catalytic oxidation properties are also observed for model soot particles, Printex-U, when mixed with Fe/C-TiO2. With regards to Si–TiO2 nanoparticles, a uniform coating of 3 to 8 nm of silicon dioxide is observed around the TiO2 particles. This coating mainly occurs due to variance in the chemical reaction rates of the precursors. Finally, with regards to V–TiO2, vanadium is doped within the TiO2 nanoparticles as visualized by HRTEM and XPS further confirms the formation of

  15. Synthesis of TiO{sub 2} nanoparticles containing Fe, Si, and V using multiple diffusion flames and catalytic oxidation capability of carbon-coated nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Mohamed A. [King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (Saudi Arabia); Memon, Nasir K., E-mail: nmemon@qf.org.qa [HBKU, Qatar Foundation, Qatar Environment and Energy Research Institute (QEERI) (Qatar); Hedhili, Mohamed N.; Anjum, Dalaver H. [KAUST, Imaging and Characterization Lab (Saudi Arabia); Chung, Suk Ho [King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (Saudi Arabia)

    2016-01-15

    Titanium dioxide (TiO{sub 2}) nanoparticles containing iron, silicon, and vanadium are synthesized using multiple diffusion flames. The growth of carbon-coated (C–TiO{sub 2}), carbon-coated with iron oxide (Fe/C–TiO{sub 2}), silica-coated (Si–TiO{sub 2}), and vanadium-doped (V–TiO{sub 2}) TiO{sub 2} nanoparticles is demonstrated using a single-step process. Hydrogen, oxygen, and argon are utilized to establish the flame, with titanium tetraisopropoxide (TTIP) as the precursor for TiO{sub 2}. For the growth of Fe/C–TiO{sub 2} nanoparticles, TTIP is mixed with xylene and ferrocene. While for the growth of Si–TiO{sub 2} and V–TiO{sub 2}, TTIP is mixed with hexamethyldisiloxane (HMDSO) and vanadium (V) oxytriisopropoxide, respectively. The synthesized nanoparticles are characterized using high-resolution transmission electron microscopy (HRTEM) with energy-filtered TEM for elemental mapping (of Si, C, O, and Ti), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption BET surface area analysis, and thermogravimetric analysis. Anatase is the dominant phase for the C–TiO{sub 2}, Fe/C–TiO{sub 2}, and Si–TiO{sub 2} nanoparticles, whereas rutile is the dominant phase for the V–TiO{sub 2} nanoparticles. For C–TiO{sub 2} and Fe/C–TiO{sub 2}, the nanoparticles are coated with about 3-5-nm thickness of carbon. The iron-based TiO{sub 2} nanoparticles significantly improve the catalytic oxidation of carbon, where complete oxidation of carbon occurs at a temperature of 470 °C (with iron) compared to 610 °C (without iron). Enhanced catalytic oxidation properties are also observed for model soot particles, Printex-U, when mixed with Fe/C-TiO{sub 2}. With regards to Si–TiO{sub 2} nanoparticles, a uniform coating of 3 to 8 nm of silicon dioxide is observed around the TiO{sub 2} particles. This coating mainly occurs due to variance in the chemical reaction rates of the precursors. Finally, with regards

  16. Internalization and cytotoxicity effects of carbon-encapsulated iron nanoparticles in murine endothelial cells: Studies on internal dosages due to loaded mass agglomerates.

    Science.gov (United States)

    Cywinska, Monika A; Bystrzejewski, Michal; Poplawska, Magdalena; Kosmider, Anita; Zdanowski, Robert; Lewicki, Slawomir; Fijalek, Zbigniew; Ostrowska, Agnieszka; Bamburowicz, Magdalena; Cieszanowski, Andrzej; Grudzinski, Ireneusz P

    2016-08-01

    Carbon-encapsulated iron nanoparticles (CEINs) qualified as metal-inorganic hybrid nanomaterials offer a potential scope for an increasing number of biomedical applications. In this study, we have focused on the investigation of cellular fate and resulting cytotoxic effects of CEINs synthesized using a carbon arc route and studied in murine endothelial (HECa-10) cells. The CEIN samples were characterized as pristine (the mean diameter between 47 and 56nm) and hydrodynamic (the mean diameter between 270 and 460nm) forms and tested using a battery of methods to determine the cell internalization extent and cytotoxicity effects upon to the exposures (0.0001-100μg/ml) in HECa-10 cells. Our studies evidenced that the incubation with CEINs for 24h is accompanied with substantial changes of Zeta potential in cells which can be considered as a key factor for affecting the membrane transport, cellular distribution and cytotoxicity of these nanoparticles. The results demonstrate that CEINs have entered the endothelial cell through the endocytic pathway rather than by passive diffusion and they were mainly loaded as agglomerates on the cell membrane and throughout the cytoplasm, mitochondria and nucleus. The studies show that CEINs induce the mitochondrial and cell membrane cytotoxicities in a dose-dependent manner resulting from the internal dosages due to CEIN agglomerates. Our results highlight the importance of the physicochemical characterization of CEINs in studying the magnetic nanoparticle-endothelial cell interactions because the CEIN mass agglomerates can sediment more or less rapidly in culture models. PMID:27107485

  17. Ecotoxicological effect of sublethal exposure to zinc oxide nanoparticles on freshwater snail Biomphalaria alexandrina.

    Science.gov (United States)

    Fahmy, Sohair R; Abdel-Ghaffar, Fathy; Bakry, Fayez A; Sayed, Dawlat A

    2014-08-01

    Freshwater snails are used as sensitive biomarkers of aquatic ecosystem pollution. The potential impacts of zinc oxide nanoparticles (ZnONPs) on aquatic ecosystems have attracted special attention due to their unique properties. The present investigation was designed to evaluate the possible mechanisms of ecotoxicological effects of ZnONPs on freshwater snail Biomphalaria alexandrina. ZnONPs showed molluscicidal activity against B. alexandrina snails, and the LC50 was 145 μg/ml. Two tested concentrations of ZnONPs were selected: The first concentration was equivalent to LC10 (7 μg/ml), and the second was equivalent to LC25 (35 μg/ml). Exposure to ZnONPs (7 and 35 μg/ml) for three consecutive weeks significantly induced malondialdehyde and nitric oxide with concomitant decreases in glutathione and glutathione-S-transferase levels in hemolymph and soft tissues of treated snails. Moreover, ZnONPs elicited a significant decrease in total protein and albumin contents coinciding with enhancement of total lipids and cholesterol levels as well as activities of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase in hemolymph and soft tissues of treated snails. This study highlights the potential ecological implications of ZnONP release in aquatic environments and may serve to encourage regulatory agencies in Egypt to more carefully monitor and regulate the industrial use and disposal of ZnONPs. PMID:24736985

  18. Photothermal properties of gold nanoparticles under exposure to high optical energies

    International Nuclear Information System (INIS)

    Photothermal (PT) efficacy and damage thresholds of gold nanoparticles (NP)-spheres, rods and silica-gold shells-were experimentally studied during their excitation with nanosecond laser pulses at the fluence levels at and above the NP damage threshold. The maxima of PT efficacy of gold NPs with near-infrared (NIR) plasmon resonances (gold rods and shells) and the minima of their damage thresholds were found to be shifted from their plasmon resonance NIR wavelengths into non-resonant visible wavelengths. This suppression of PT efficacy of NIR plasmon resonances (bleaching) was found to be up to 18 times for the rods and up to 22 times for the shells. During laser-induced deterioration the NPs maintained their PT properties at least within 40-150 ns after exposure to laser pulses. PT properties of the gold NPs can be enhanced with the pulse train mode within the above time. The PT bubbles generated around superheated NPs were used as their optical markers and allowed us to quantify PT efficacy of plasmon resonance through the bubble parameters under the conditions when other methods of NP detection are not applicable

  19. Exposure to nickel oxide nanoparticles induces pulmonary inflammation through NLRP3 inflammasome activation in rats.

    Science.gov (United States)

    Cao, Zhengwang; Fang, Yiliang; Lu, Yonghui; Qian, Fenghua; Ma, Qinglong; He, Mingdi; Pi, Huifeng; Yu, Zhengping; Zhou, Zhou

    2016-01-01

    With recent advances in the manufacture and application of nickel oxide nanoparticles (NiONPs), concerns about their adverse effects on the respiratory system are increasing. However, the underlying cellular and molecular mechanisms of NiONP-induced pulmonary toxicity remain unclear. In this study, we focused on the impacts of NiONPs on pulmonary inflammation and investigated whether the NLRP3 inflammasome is involved in NiONP-induced pulmonary inflammation and injury. NiONP suspensions were administered by single intratracheal instillation to rats, and inflammatory responses were evaluated at 3 days, 7 days, or 28 days after treatment. NiONP exposure resulted in sustained pulmonary inflammation accompanied by inflammatory cell infiltration, alveolar proteinosis, and cytokine secretion. Expression of Nlrp3 was markedly upregulated by the NiONPs, which was accompanied by overexpression of the active form of caspase-1 (p20) and interleukin (IL)-1β secretion in vivo. NiONP-induced IL-1β secretion was partially prevented by co-treatment with a caspase-1 inhibitor in macrophages. Moreover, siRNA-mediated Nlrp3 knockdown completely attenuated NiONP-induced cytokine release and caspase-1 activity in macrophages in vitro. In addition, NiONP-induced NLRP3 inflammasome activation requires particle uptake and reactive oxygen species production. Collectively, our findings suggest that the NLRP3 inflammasome participates in NiONP-induced pulmonary inflammation and offer new strategies to combat the pulmonary toxicity induced by NiONPs. PMID:27524893

  20. Oral toxic exposure of titanium dioxide nanoparticles on serum biochemical changes in adult male Wistar rats

    Directory of Open Access Journals (Sweden)

    Dasal Vasantharaja

    2015-01-01

    Full Text Available Objective(s: Titanium dioxide (TiO2 nanoparticles (NPs are widely used in commercial food additives and cosmetics worldwide. Uptake of these nanoparticulate into humans by different routes and may exhibit potential side effects, lags behind the rapid development of nanotechnology. Thus, the present study designed to evaluate the toxic effect of mixed rutile and anatase TiO2 NPs on serum biochemical changes in rats. Materials and Methods: In this study, adult male Wistar rats were randomly allotted into the experimental and control groups (n=6, which were orally administered with 50 and 100 mg/kg body weight of TiO2 NPs. Toxic effects were assessed by the changes of serum biochemical parameters such as glucose, total protein, albumin, globulin, cholesterol, triglyceride, high density lipoprotein, alanine transaminase, aspartate transaminase, alkaline phosphatase, total bilirubin, blood urea nitrogen, uric acid and creatinine. All the serum biochemical markers were experimented in rats, after 14-days of post exposure. Results: Changes of the serum specific parameters indicated that liver and kidney were significantly affected in both experimental groups. The changes between the levels of total protein, glucose, aspartate transaminase, alanine transaminase and alkaline phosphatase indicate that TiO2 NPs induces liver damage. Significant increase in the blood urea nitrogen and uric acid indicates the renal damage in the TiO2 NPs treated rats. Conclusion: The data shows that the oral administration of TiO2 NPs (

  1. Translocation of particles and inflammatory responses after exposure to fine particles and nanoparticles in an epithelial airway model

    Directory of Open Access Journals (Sweden)

    Musso Claudia

    2007-09-01

    Full Text Available Abstract Background Experimental studies provide evidence that inhaled nanoparticles may translocate over the airspace epithelium and cause increased cellular inflammation. Little is known, however, about the dependence of particle size or material on translocation characteristics, inflammatory response and intracellular localization. Results Using a triple cell co-culture model of the human airway wall composed of epithelial cells, macrophages and dendritic cells we quantified the entering of fine (1 μm and nano-sized (0.078 μm polystyrene particles by laser scanning microscopy. The number distribution of particles within the cell types was significantly different between fine and nano-sized particles suggesting different translocation characteristics. Analysis of the intracellular localization of gold (0.025 μm and titanium dioxide (0.02–0.03 μm nanoparticles by energy filtering transmission electron microscopy showed differences in intracellular localization depending on particle composition. Titanium dioxide nanoparticles were detected as single particles without membranes as well as in membrane-bound agglomerations. Gold nanoparticles were found inside the cells as free particles only. The potential of the different particle types (different sizes and different materials to induce a cellular response was determined by measurements of the tumour necrosis factor-α in the supernatants. We measured a 2–3 fold increase of tumour necrosis factor-α in the supernatants after applying 1 μm polystyrene particles, gold nanoparticles, but not with polystyrene and titanium dioxide nanoparticles. Conclusion Quantitative laser scanning microscopy provided evidence that the translocation and entering characteristics of particles are size-dependent. Energy filtering transmission electron microscopy showed that the intracellular localization of nanoparticles depends on the particle material. Both particle size and material affect the cellular

  2. Exposure assessment and engineering control strategies for airborne nanoparticles: an application to emissions from nanocomposite compounding processes

    International Nuclear Information System (INIS)

    In this study, nanoalumina and nanoclay particles were compounded separately with ethylene vinyl acetate (EVA) polymer to produce nanocomposites using a twin-screw extruder to investigate exposure and effective controls. Nanoparticle exposures from compounding processes were elevated under some circumstances and were affected by many factors including inadequate ventilation, surrounding air flow, feeder type, feeding method, and nanoparticle type. Engineering controls such as improved ventilation and enclosure of releasing sources were applied to the process equipment to evaluate the effectiveness of control. The nanoparticle loading device was modified by installing a ventilated enclosure surrounding the loading chamber. Exposures were studied using designed controls for comparison which include three scenarios: (1) no isolation; (2) enclosed sources; and (3) enclosed sources and improved ventilation. Particle number concentrations for diameters from 5 to 20,000 nm measured by the Fast Mobility Particle Sizer and aerodynamic particle sizer were studied. Aerosol particles were sampled on transmission electron microscope grids to characterize particle composition and morphology. Measurements and samples were taken at the near- and far-field areas relative to releasing sources. Airborne particle concentrations were reduced significantly when using the feeder enclosure, and the concentrations were below the baseline when two sources were enclosed, and the ventilation was improved when using either nanoalumina or nanoclay as fillers.

  3. Acute Lung Injury Due To Carbon Monoxide Exposure

    Directory of Open Access Journals (Sweden)

    Uzkeser M et al.

    2012-10-01

    Full Text Available A 20-year-old woman, who was found unconscious in the bed by the morning, was brought to emergency department. Her carboxyhemoglobin level was 20.2%. The portable chest X-ray showed bilaterally alveolar and interstitial infiltration. Initial pO 2 /FIO 2 ratio was calculated as 119 mmHg. Acute lung injury due to carbon monoxide intoxication was considered. She was intubated and mechanical ventilation was applied. In the second day of hospitalization, a clear improvement was observed on the chest X-ray. She was discharged without any complication on the seventh day of hospitalization. Early diagnosis and treatment may prevent progression of ARDS and progression of permanent damage, and may lead to complete recovery.

  4. One-step facile synthesis of carbon-supported PdAu nanoparticles and their electrochemical property and stability

    International Nuclear Information System (INIS)

    Graphical abstract: Well-crystallized PdAu alloy nanoparticles with the average size of 2–5 nm supported on Ketjen Black (KB) were successfully fabricated from the metal wire electrodes via a one-step solution plasma process in water at atmospheric pressure. Multi-scan cyclic voltammetry showed they have better electrochemical stability in alkaline than in acidic solution. - Highlights: • Carbon-supported PdAu nanoparticles were fabricated by a solution plasma technique. • As-obtained PdAu nanoparticles were confirmed to be alloy. • PdAu nanoparticles have good electrochemical activities and stabilities. • PdAu nanoparticles in alkaline have better stability than that in acidic solution. - Abstract: Well-crystallized PdAu nanoparticles supported on Ketjen Black (KB) were successfully fabricated when both Pd and Au wires were served as the electrode pair by a solution plasma technique at atmospheric pressure. The synthesis of PdAu nanoparticles was almost simultaneous with their dispersion on KB. As-obtained PdAu nanoparticles were confirmed to be alloy by ultraviolet–visible spectrophotometer, transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX) of each particle. PdAu nanoparticles with the average diameter of 2–5 nm were equably distributed on KB. PdAu nanoparticles showed good electrocatalytic activity both in acidic and alkaline solution corresponding to their obvious oxidation and reduction features. PdAu nanoparticles have improved electrochemical stability compared with the electrochemical properties of Pd and Au nanoparticles mixture after long time multi-scan cyclic voltammetry. Multi-scan cyclic voltammetry also presented the PdAu nanoparticles in alkaline solution have better stability than that in acidic solution. Thus as-obtained PdAu alloy nanoparticles would become a promising electrocatalysts for fuel cells or Li-air batteries. This novel process showed its potential applications in designing optimization of

  5. One-step facile synthesis of carbon-supported PdAu nanoparticles and their electrochemical property and stability

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiulan, E-mail: whoxiulan@163.com [College of Materials Science and Engineering, Nanjing Tech University (China); Shi, Junjun; Zhang, Jianbo [College of Materials Science and Engineering, Nanjing Tech University (China); Tang, Weiping [Shanghai Institute of Space Power Sources, Shanghai (China); Zhu, Haikui; Shen, Xiaodong [College of Materials Science and Engineering, Nanjing Tech University (China); Saito, Nagahiro [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University (Japan)

    2015-01-15

    Graphical abstract: Well-crystallized PdAu alloy nanoparticles with the average size of 2–5 nm supported on Ketjen Black (KB) were successfully fabricated from the metal wire electrodes via a one-step solution plasma process in water at atmospheric pressure. Multi-scan cyclic voltammetry showed they have better electrochemical stability in alkaline than in acidic solution. - Highlights: • Carbon-supported PdAu nanoparticles were fabricated by a solution plasma technique. • As-obtained PdAu nanoparticles were confirmed to be alloy. • PdAu nanoparticles have good electrochemical activities and stabilities. • PdAu nanoparticles in alkaline have better stability than that in acidic solution. - Abstract: Well-crystallized PdAu nanoparticles supported on Ketjen Black (KB) were successfully fabricated when both Pd and Au wires were served as the electrode pair by a solution plasma technique at atmospheric pressure. The synthesis of PdAu nanoparticles was almost simultaneous with their dispersion on KB. As-obtained PdAu nanoparticles were confirmed to be alloy by ultraviolet–visible spectrophotometer, transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX) of each particle. PdAu nanoparticles with the average diameter of 2–5 nm were equably distributed on KB. PdAu nanoparticles showed good electrocatalytic activity both in acidic and alkaline solution corresponding to their obvious oxidation and reduction features. PdAu nanoparticles have improved electrochemical stability compared with the electrochemical properties of Pd and Au nanoparticles mixture after long time multi-scan cyclic voltammetry. Multi-scan cyclic voltammetry also presented the PdAu nanoparticles in alkaline solution have better stability than that in acidic solution. Thus as-obtained PdAu alloy nanoparticles would become a promising electrocatalysts for fuel cells or Li-air batteries. This novel process showed its potential applications in designing optimization of

  6. Aptamer biosensor for dopamine based on a gold electrode modified with carbon nanoparticles and thionine labeled gold nanoparticles as probe

    International Nuclear Information System (INIS)

    We describe a biosensor for dopamine that is based on the use of a gold electrode modified with carbon nanoparticles (CNPs) coupled to thionine labeled gold nanoparticles (AuNPs) acting as signal amplifiers. The biosensor was constructed by first modifying the CNPs on the gold electrode and adsorbing the thionine on the surface of the AuNPs, and then linking the complementary strand of the dopamine aptamer to the AuNPs via gold-thiol chemistry. Next, dopamine aptamer is added and the duplex is formed on the surface. On addition of a sample containing dopamine, it will interact with aptamer and cause the release of the electrochemical probe which then will be adsorbed on the surface of the CNP-modified gold electrode and detected by differential pulse voltammetry. The current is linearly related to the concentration of dopamine in the 30 nM to 6.0 μM ranges. The detection limit is as low as 10 nM, and the RSD is 3.1 % at a 0.3 μM level (for n = 11). The protocol was successfully applied to the determination of dopamine in spiked human urine samples. We perceive that this method holds promise as a widely applicable platform for aptamer-based electrochemical detection of small molecules. (author)

  7. CARBON MONOXIDE EXPOSURES INSIDE AN AUTOMOBILE TRAVELING ON AN URBAN ARTERIAL HIGHWAY

    Science.gov (United States)

    Carbon monoxide (CO) exposures were measured inside a motor vehicle during 88 standardized drives on a major urban arterial highway, El Camino Real (traffic volume of 30,500-45,000 vehicles per day), over a 13-1/2 month period. n each trip (lasting between 31 and 61 minutes), the...

  8. Effects of lung exposure to carbon nanotubes on female fertility and pregnancy. A study in mice

    DEFF Research Database (Denmark)

    Hougaard, Karin S.; Jackson, Petra; Kyjovska, Zdenka O.;

    2013-01-01

    We studied the effects of preconceptional exposure to multiwalled carbon nanotubes (MWCNTs): mature, female C57BL/6J mice were intratracheally instilled with 67μg NM-400 MWCNT, and the following day co-housed with mature males, in breeding pairs. Time to delivery of the first litter, litter param...

  9. Adsorption of superparamagnetic iron oxide nanoparticles on silica and calcium carbonate sand.

    Science.gov (United States)

    Park, Yoonjee C; Paulsen, Jeffrey; Nap, Rikkert J; Whitaker, Ragnhild D; Mathiyazhagan, Vidhya; Song, Yi-Qiao; Hürlimann, Martin; Szleifer, Igal; Wong, Joyce Y

    2014-01-28

    Superparamagnetic iron oxide (SPIO) nanoparticles have the potential to be used in the characterization of porous rock formations in oil fields as a contrast agent for NMR logging because they are small enough to traverse through nanopores and enhance contrast by shortening NMR T2 relaxation time. However, successful development and application require detailed knowledge of particle stability and mobility in reservoir rocks. Because nanoparticle adsorption to sand (SiO2) and rock (often CaCO3) affects their mobility, we investigated the thermodynamic equilibrium adsorption behavior of citric acid-coated SPIO nanoparticles (CA SPIO NPs) and poly(ethylene glycol)-grafted SPIO nanoparticles (PEG SPIO NPs) on SiO2 (silica) and CaCO3 (calcium carbonate). Adsorption behavior was determined at various pH and salt conditions via chemical analysis and NMR, and the results were compared with molecular theory predictions. Most of the NPs were recovered from silica, whereas far fewer NPs were recovered from calcium carbonate because of differences in the mineral surface properties. NP adsorption increased with increasing salt concentration: this trend was qualitatively explained by molecular theory, as was the role of the PEG grafting in preventing NPs adsorption. Quantitative disagreement between the theoretical predictions and the data was due to NP aggregation, especially at high salt concentration and in the presence of calcium carbonate. Upon aggregation, NP concentrations as determined by NMR T2 were initially overestimated and subsequently corrected using the relaxation rate 1/T2, which is a function of aggregate size and fractal dimension of the aggregate. Our experimental validation of the theoretical predictions of NP adsorption to minerals in the absence of aggregation at various pH and salt conditions demonstrates that molecular theory can be used to determine interactions between NPs and relevant reservoir surfaces. Importantly, this integrated experimental and

  10. Synthesis of mesoporous zeolite catalysts by in situ formation of carbon template over nickel nanoparticles

    DEFF Research Database (Denmark)

    Abildstrøm, Jacob Oskar; Kegnæs, Marina; Hytoft, Glen;

    2016-01-01

    A novel synthesis procedure for the preparation of the hierarchical zeolite materials with MFI structure based on the carbon templating method with in situ generated carbon template is presented in this study. Through chemical vapour deposition of coke on nickel nanoparticles supported on silica...

  11. Regional cerebral blood flow after long-term exposure to carbon disulfide

    International Nuclear Information System (INIS)

    Sixteen former rayon viscose workers were investigated four years after the exposure to carbon disulfide was discontinued. Median age was 58 years (range 43-65 years), median exposure time was 17 years (range 10-35 years). Encephalopathy was diagnosed in altogether 14 workers. To further explore pathophysiological mechanisms, cerebrovascular investigations were employed. Doppler ultrasound examination of the precerebral vessels in 15 workers showed a slight stenosis of the left internal carotid artery in one. Regional cerebral blood flow investigation (rCBF) with single photon emission computerized tomography (SPECT) with Xenon-133 gas was performed in 14. There was no significant difference from a control group. Regional side-to-side asymmetries beyond reference limits were demonstrated in eight workers. The abnormalities were modest, but may indicate a tendency toward focal blood flow disturbances in workers with long-term exposure to carbon disulfide. (au)

  12. Facile synthesis of platinum nanoparticle-containing porous carbons, and their application to amperometric glucose biosensing

    International Nuclear Information System (INIS)

    This study describes the facile synthesis of platinum nanoparticle-containing porous carbons (Pt/C) by carbonization of freeze-dried agarose gels containing potassium tetrachloroplatinate under a nitrogen atmosphere at 800 °C. By adjusting the ratio between agarose and platinate in the freeze-dried gels, the Pt content in the final Pt/C products could be systematically varied from 0–10 wt.%. Transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray photoelectron spectroscopy, Raman spectroscopy, and nitrogen physisorption measurements revealed that the Pt/C materials obtained by this method possess high surface areas (350–500 m2 g−1), narrow Pt nanoparticle size distributions (6 ± 3 nm) and nanocrystalline graphite –like carbon character. By immobilization of glucose oxidase on the surface of a 4 wt.% Pt/C electrocatalyst prepared by this route, a very sensitive amperometric glucose biosensor was obtained (response time <2 min, sensitivity 1.9 mA M−1; and a linear response with glucose concentration up to 10 mM). The simplicity and versatility of the described synthetic method suggests its application to the preparation of carbon supported noble metal catalysts including palladium/C and gold/C. (author)

  13. Electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes

    International Nuclear Information System (INIS)

    In this study, a novel methodology for the electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes has been investigated. The morphology, the structure, and the electrochemical performance of the multi-walled carbon nanotubes-silver (MWCNT-Ag) nanocomposite film were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry (CV), respectively. Electrocatalytic oxidation of benzene in an aqueous solution was studied to evaluate potential applications of the MWCNT-Ag modified glassy carbon (GC) electrode in environmental science. The benzene removal efficiency in natural water containing 10 mg L−1 benzene yielded 77.9% at an applied potential of +2.0 V for 2 h using the MWCNT-Ag-GC electrode. In comparison, the removal efficiency reached only 8.0% with the bare GC electrode, showing the suitability of the MWCNT-Ag nanocomposite modified GC electrode for electro-oxidation of benzene in natural water. - Graphical abstract: Display Omitted - Highlights: • A novel methodology for the electrochemical degradation of benzene was developed. • Sensor based on silver nanoparticle-decorated carbon nanotubes was used. • The proposed method is suitable and efficient for the removal of benzene

  14. Photocatalytic removal of polychlorinated biphenyls (PCBs) using carbon-modified titanium oxide nanoparticles

    Science.gov (United States)

    Shaban, Yasser A.; El Sayed, Mohamed A.; El Maradny, Amr A.; Al Farawati, Radwan Kh.; Al Zobidi, Mosa I.; Khan, Shahed U. M.

    2016-03-01

    In this work, the sonicated sol-gel method was used for synthesizing carbon-modified titanium oxide nanoparticles. Carbon incorporation was achieved by using titanium (IV) isopropoxide as a titanium and carbon-containing precursor. The photocatalytic efficiency of the synthesized photocatalyst was assessed by examining the photocatalytic removal of polychlorinated biphenyls (PCBs) from aqueous solution. For comparison, unmodified (regular) titanium dioxide (n-TiO2) was used as a reference catalyst. To confirm the carbon incorporation in CM-n-TiO2 nanoparticles, energy dispersive spectroscopy (EDS) analysis was used. Significantly, the bandgap energy was found to be reduced from 2.99 eV for n-TiO2 to 1.8 eV for CM-n-TiO2, which in turn improved the performance of CM-n-TiO2 toward the photocatalytic removal of PCBs. The effects of CM-n-TiO2 loading, PCBs concentration, and pH of the solution on the photodegradation rate of PCBs were investigated. The highest removal rate was found to be at pH 5 and CM-n-TiO2 loading of 0.5 g L-1. According to Langmuir-Hinshelwood model, the photodegradation of PCBs using CM-n-TiO2 followed a pseudo-first order reaction kinetics.

  15. Electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cesarino, Ivana, E-mail: ivana@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil); Cesarino, Vivian; Moraes, Fernando C.; Ferreira, Tanare C.R.; Lanza, Marcos R.V. [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil); Mascaro, Lucia H. [Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13560-970, São Carlos, SP (Brazil); Machado, Sergio A.S. [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil)

    2013-08-15

    In this study, a novel methodology for the electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes has been investigated. The morphology, the structure, and the electrochemical performance of the multi-walled carbon nanotubes-silver (MWCNT-Ag) nanocomposite film were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry (CV), respectively. Electrocatalytic oxidation of benzene in an aqueous solution was studied to evaluate potential applications of the MWCNT-Ag modified glassy carbon (GC) electrode in environmental science. The benzene removal efficiency in natural water containing 10 mg L{sup −1} benzene yielded 77.9% at an applied potential of +2.0 V for 2 h using the MWCNT-Ag-GC electrode. In comparison, the removal efficiency reached only 8.0% with the bare GC electrode, showing the suitability of the MWCNT-Ag nanocomposite modified GC electrode for electro-oxidation of benzene in natural water. - Graphical abstract: Display Omitted - Highlights: • A novel methodology for the electrochemical degradation of benzene was developed. • Sensor based on silver nanoparticle-decorated carbon nanotubes was used. • The proposed method is suitable and efficient for the removal of benzene.

  16. Molecular dynamics study of the stability of a carbon nanotube atop a catalytic nanoparticle

    Science.gov (United States)

    Verkhovtsev, Alexey V.; Schramm, Stefan; Solov'yov, Andrey V.

    2014-09-01

    The stability of a single-walled carbon nanotube placed on top of a catalytic nickel nanoparticle is investigated by means of molecular dynamics simulations. As a case study, we consider the (12,0) nanotube consisting of 720 carbon atoms and the icosahedral Ni309 cluster. An explicit set of constant-temperature simulations is performed in order to cover a broad temperature range from 400 to 1200 K, at which a successful growth of carbon nanotubes has been achieved experimentally by means of chemical vapor deposition. The stability of the system depending on parameters of the involved interatomic interactions is analyzed. It is demonstrated that different scenarios of the nanotube dynamics atop the nanoparticle are possible depending on the parameters of the Ni-C potential. When the interaction is weak the nanotube is stable and resembles its highly symmetric structure, while an increase of the interaction energy leads to the abrupt collapse of the nanotube in the initial stage of simulation. In order to validate the parameters of the Ni-C interaction utilized in the simulations, DFT calculations of the potential energy surface for carbon-nickel compounds are performed. The calculated dissociation energy of the Ni-C bond is in good agreement with the values, which correspond to the case of a stable and not deformed nanotube simulated within the MD approach.

  17. A new carbon monoxide occupational dosimeter: results from a worker exposure assessment survey.

    Science.gov (United States)

    Apte, M G; Cox, D D; Hammond, S K; Gundel, L A

    1999-01-01

    The LBNL/QGI occupational carbon monoxide (CO) dosimeter (LOCD), a new, inexpensive CO passive sampler, was field-validated in an occupational exposure assessment study in the Moscone Convention Center (MCC) in San Francisco, CA in January, 1997. The LOCD measures time-weighed-average (TWA) CO exposures from 10 to 800 parts per million hours (ppm h; accuracy +/- 20%; precision 10 ppm h). This device represents a major improvement over currently available low-cost personal CO monitors. At the MCC, over 1000 workers set up and remove exhibitions. Forty propane-powered forklifts moved materials throughout the 42,000 m2 of exhibit halls. Diesel truck emissions enter the building via three internal underground loading docks. The LOCD was used to measure 154 worker exposures on 3 days. Sampler performance was compared to a standard method at 15 fixed sites. The geometric mean (GM) of all 154 exposures was 7 ppm (geometric standard deviation (GSD) = 1.6); 10% of the exposures was 10 ppm or more. Dock Walkers and Forklift Operators had the highest exposures (maximum = 34 ppm) with GM (GSD) of 9 (1.7) and 9 (1.6) ppm, respectively. Attendants and Installer/Decorators had the lowest exposures with GMs of 6 (1.6) and 7 (1.4), respectively. The Cal/OSHA personal exposure limit for CO is 25 ppm time-weighted average (TWA). PMID:10638840

  18. Gold Nanoparticle-based Layer-by-Layer Enhancement of DNA Hybridization Electrochemical Signal at Carbon Nanotube Modified Carbon Paste Electrode

    Institute of Scientific and Technical Information of China (English)

    Li Bo NIE; Jian Rong CHEN; Yu Qing MIAO; Nong Yue HE

    2006-01-01

    Colloid gold nanoparticle-based layer-by-layer amplification approach was applied to enhance the electrochemical detection sensitivity of DNA hybridization at carbon nanotube modified carbon paste electrodes (CNTPEs). Streptavidin was immobilized onto the surface of CNTPEs, and the conjugation of biotin labeled target oligonucleotides to the above immobilized streptavidin was performed, followed by the hybridization of target oligonucleotides with the gold nanoparticle-labeled DNA probe and then the layer-by-layer enhanced connection of gold nanoparticles, on which oligonucleotides complementary to the DNA probe were attached, to the hybridization system. The differential pulse voltammetry (DPV) signal of total gold nanoparticles was monitored. It was found that the layer-by-layer colloidal gold DPV detection enhanced the sensitivity by about one order of magnitude compared with that of one-layer detection. One-base mismatched DNA and complementary DNA could be distinguished clearly.

  19. Manipulation of combustion waves in carbon-nanotube/fuel composites by highly reactive Mg nanoparticles.

    Science.gov (United States)

    Lee, Kang Yeol; Hwang, Hayoung; Shin, Dongjoon; Choi, Wonjoon

    2015-10-28

    Manipulating the interface of micro/nanostructured materials and chemical fuels can change the fundamental characteristics of combustion waves that are generated during a reaction. In this study, we report that Mg/MgO nanoparticles actively amplify the propagation of combustion waves at the interface of multi-walled carbon nanotubes (MWCNTs) and chemical fuels. Fuel/MWCNT and fuel/MWCNT-Mg/MgO composite films were prepared by a facile synthetic method. We present complete physiochemical characterization of these composite films and evaluate the propagating velocities and real-time surface temperatures of combustion waves. Mg/MgO nanoparticles at the interface enhanced the reaction front velocity by 41%. The resulting explosive reactions supplied additional thermal energy to the chemical fuel, accelerating flame propagation. Furthermore, the surface temperatures of the composites with Mg/MgO nanoparticles were much lower, indicating how the transient heat from the reaction would ignite the unreacted fuels at lower surface temperatures despite not reaching the necessary activation energy for a chain reaction. This mechanism contributed to thermopower waves that amplified the output voltage. Furthermore, large temperature gradients due to the presence of nanoparticles increased charge transport inside the nanostructured material, due to the increased thermoelectric effects. This manipulation could contribute to the active control of interfacially driven combustion waves along nanostructured materials, yielding many potential applications. PMID:26419765

  20. Blood-bound carbon disulfide: an indicator of carbon disulfide exposure, and its accumulation in repeatedly exposed rats.

    Science.gov (United States)

    Lam, C W; DiStefano, V

    1983-09-30

    Carbon disulfide is present in exposed subjects in free and bound or acid-labile forms. Sensitivities of the blood acid-labile CS2 (AL CS2) concentration and the modified iodine-azide test (IAT) were compared as indicators of CS2 exposure. Rats were exposed to 15 (approximately 5 ppm), 30, 60, or 120 mg/m3 of CS2. Exposure to 15 or 30 mg/m3 of CS2 could not be detected by the modified IAT. However, a linear relationship between blood CS2 (free or AL CS2) concentrations and these exposure levels was observed. Free CS2 is eliminated rapidly, while AL CS2 is eliminated very slowly from the exposed subjects. Repetitive daily exposures (8 hr/day) to 120 mg/m3 of CS2 were carried out in rats. Blood AL CS2 concentrations in exposed rats increased with each successive exposure while the free CS2 level remained relatively constant. By the sixth or seventh daily exposure the blood AL CS2 concentration was about 2.5 times that of the first 8-hr exposure and about 3 times the level of free CS2. These results indicated an appreciable accumulation of CS2 in subjects repeatedly exposed to low concentrations of the solvent. Rats were also exposed to CS2 8 hr/day for 5 days. After a 2-day nonexposure period (Days 6 and 7), the animals were reexposed on Day 8. The blood AL CS2 concentration in animals exposed on Day 8 was substantially higher than in those that received a single 8-hr exposure (Day 1), despite the hiatus on Days 6 and 7. These results indicated that blood AL CS2 was not totally eliminated during the 2-day nonexposure period. In in vitro experiments, the binding profile of CS2 to human blood was remarkably similar to that of rats exposed to CS2 by inhalation. PMID:6636170

  1. Highly sensitive hydrogen peroxide sensor based on a glassy carbon electrode modified with platinum nanoparticles on carbon nanofiber heterostructures

    International Nuclear Information System (INIS)

    We are presenting a sensor for hydrogen peroxide (H2O2) that is based on the use of a heterostructure composed of Pt nanoparticles (NPs) and carbon nanofibers (CNFs). High-density Pt NPs were homogeneously loaded onto a three-dimensional nanostructured CNF matrix and then deposited in a glassy carbon electrode (GCE). The resulting sensor synergizes the advantages of the conducting CNFs and the nanoparticle catalyst. The porous structure of the CNFs also favor the high-density immobilization of the NPs and the diffusion of water-soluble molecules, and thus assists the rapid catalytic oxidation of H2O2. If operated at a working voltage of −0.2 V (vs. Ag/AgCl), the modified GCE exhibits a linear response to H2O2 in the 5 μM to 15 mM concentration range (total analytical range: 5 μM to 100 mM), with a detection limit of 1.7 μM (at a signal-to-noise ratio of 3). The modified GCE is not interfered by species such as uric acid and glucose. Its good stability, high selectivity and good reproducibility make this electrode a valuable tool for inexpensive amperometric sensing of H2O2. (author)

  2. Synthesis of β-SiC nanowires by ball milled nanoparticles of silicon and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Pengchao, E-mail: kangpc@hit.edu.cn [Materials Science and Engineering School, Harbin Institute of Technology, P.O.B. 433, Harbin 150001 (China); Zhang, Bin; Wu, Gaohui; Gou, Huasong; Chen, Guoqin; Jiang, Longtao [Materials Science and Engineering School, Harbin Institute of Technology, P.O.B. 433, Harbin 150001 (China); Mula, Suhrit [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2014-08-01

    Highlights: • The β-SiC nanowires were synthesized only use milled Si and C nanoparticles. • No catalyst was used in this process. • The grown mechanism of β-SiC nanowires is nanoparticles self-assembly and solid–solid reaction. • This notion, together with the nanowires synthesis are expected to apply opens up other semiconductor nanomaterials. - Abstract: In the present investigation, we report a simple and new technique to synthesize silicon carbide nanowires by high energy ball milling of silicon and carbon powders followed by annealing at elevated temperatures. The detailed structural analysis was carried out by X-ray diffraction, scanning and transmission electron microscopy, and FT-IR analysis. Nanocrystalline silicon particles were detected to be covered by amorphous carbon after milling. This typical structure was transformed to β-SiC nanowires during annealing by new growth mechanism. The β-SiC nanoparticles were found to be self-assembled one by one and formed a curly chain, and then rotated gradually in accordance to the same crystal orientation along the β-SiC [1 1 1] direction.

  3. Viability preserved capture of microorganism by plasma functionalized carbon-encapsulated iron nanoparticles

    Science.gov (United States)

    Viswan, Anchu; Sugiura, Kuniaki; Nagatsu, Masaaki

    2015-09-01

    Carbon-encapsulated iron nanoparticles (Fe@C NPs) were synthesized by DC arc discharge method. Carbon encapsulation makes the particles hydrophobic, however for most of the biomedical applications they need to be hydrophilic. To attain this, the particles were amino functionalized by RF plasma. Effect of gas mixture ratio (Ar/NH3), pretreatment, post-treatment times and RF power were optimized. By varying the RF plasma conditions, the amino group population on the surface of Fe@C NPs were increased. With conventional chemical method the amino group population on particles, synthesized in different conditions was found to be ranging from 3-7 × 104 per particle. Bioconjugation efficiency of the nanoparticles was examined by biotin-avidin system, which can be simulated for antigen-antibody reactions. Results from the UV absorption and fluorescence spectroscopy shows increment in bioconjugation efficiency, with the increase of amino group population on the nanoparticles. After confirming the bioconjugation efficiency, the amino functionalized Fe@C NPs were modified with antibodies for targeting specific microorganisms. Our aim is to capture the microbes in viable and concentrated form even from less populated samples, with lesser time compared to the presently available methods. This work has been supported in part by Grant-in-Aid for Scientific Research (Nos. 21110010 and 25246029) from the Japan Society for the Promotion of Science (JSPS).

  4. Advances in Pd Nanoparticle Size Decoration of Mesoporous Carbon Spheres for Energy Application

    Science.gov (United States)

    Zielinska, Beata; Michalkiewicz, Beata; Mijowska, Ewa; Kalenczuk, Ryszard Józef

    2015-10-01

    Pd nanoparticles with different sizes and diameter distributions were successfully deposited on the surface of disordered mesoporous carbon spheres (DMHCS). The size and diameter distribution of the Pd particles were controlled by the application of different experimental conditions. Two methods of synthesis (reflux and impregnation) and two Pd precursors (palladium (II) acetyloacetonate (Pd (acac ) 2) and palladium (II) acetate (Pd(OAc)2)) were investigated and compared for the preparation of Pd-decorated DMHCS. The hydrogen storage properties of the pristine DMHCS and Pd-modified DMHCS at 40 °C and a pressure range of 0-45 bar were studied. The results showed that Pd-supported carbon samples synthesized in the presence of Pd(OAc)2 exhibited enhanced hydrogen storage capacity in respect to the pristine DMHCS. The maximum hydrogen storage of 0.38 wt.% exhibited the sample with the Pd nanoparticle diameter distribution of 2-14 nm and the average Pd crystallite size of 7.6 nm. It was found that the Pd nanoparticle content, size, and diameter distribution have a noticeable influence on H2 storage capacity.

  5. Application of Box-Behnken design to prepare gentamicin-loaded calcium carbonate nanoparticles.

    Science.gov (United States)

    Maleki Dizaj, Solmaz; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad-Hossein; Adibkia, Khosro

    2016-09-01

    The aim of this research was to prepare and optimize calcium carbonate (CaCO3) nanoparticles as carriers for gentamicin sulfate. A chemical precipitation method was used to prepare the gentamicin sulfate-loaded CaCO3 nanoparticles. A 3-factor, 3-level Box-Behnken design was used for the optimization procedure, with the molar ratio of CaCl2: Na2CO3 (X1), the concentration of drug (X2), and the speed of homogenization (X3) as the independent variables. The particle size and entrapment efficiency were considered as response variables. Mathematical equations and response surface plots were used, along with the counter plots, to relate the dependent and independent variables. The results indicated that the speed of homogenization was the main variable contributing to particle size and entrapment efficiency. The combined effect of all three independent variables was also evaluated. Using the response optimization design, the optimized Xl-X3 levels were predicted. An optimized formulation was then prepared according to these levels, resulting in a particle size of 80.23 nm and an entrapment efficiency of 30.80%. It was concluded that the chemical precipitation technique, together with the Box-Behnken experimental design methodology, could be successfully used to optimize the formulation of drug-incorporated calcium carbonate nanoparticles. PMID:25950955

  6. Commuter exposure to black carbon, carbon monoxide, and noise in the mass transport khlong boats of Bangkok, Thailand

    Science.gov (United States)

    Ziegler, A. D.; Velasco, E.; Ho, K. J.

    2013-12-01

    Khlong (canal) boats are a unique mass transport alternative in the congested city of Bangkok. Canals and rivers provide exclusive transit-ways for reducing the commuting time of thousands of city residents daily. However, as a consequence of the service characteristics and boats design and state of repair, they can represent a potential public health risk and an important source of black carbon and greenhouse gases. This work quantifies commuter exposure to black carbon, CO and noise when waiting for and travelling in these diesel fueled boats. Exposure to toxic pollutants and acute noise is similar or worse than for other transportation modes. Mean black carbon concentrations observed at one busy pier and along the main canal were much higher than ambient concentrations at sites impacted by vehicular traffic. Concentrations of CO were similar to those reported for roadside areas of Bangkok. The equivalent continuous sound levels registered at the landing pier were similar to those reported for roadsides, but values recorded inside the boats were significantly higher. We believe that the boat service is a viable alternative mode of mass transport, but public safety could be improved to provide a high quality service, comparable to modern rail systems or emerging bus rapid transit systems. These investments would also contribute to reduce the emission of black carbon and other greenhouse and toxic pollutants.

  7. An amperometric hydrogen peroxide biosensor based on Co3O4 nanoparticles and multiwalled carbon nanotube modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Highlights: • Hydrogen peroxide biosensor was constructed by combining the advantageous properties of MWCNTs and Co3O4. • Incorporating Co3O4 nanoparticles into MWCNTs/gelatin film increased the electron transfer. • Co3O4/MWCNTs/gelatin/HRP/Nafion/GCE showed strong anti-interference ability. • Hydrogen peroxide was successfully determined in disinfector with an average recovery of 100.78 ± 0.89. - Abstract: In this work a new type of hydrogen peroxide biosensor was fabricated based on the immobilization of horseradish peroxidase (HRP) by cross-linking on a glassy carbon electrode (GCE) modified with Co3O4 nanoparticles, multiwall carbon nanotubes (MWCNTs) and gelatin. The introduction of MWCNTs and Co3O4 nanoparticles not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate, resulting in a high sensitivity of the biosensor. The fabrication process of the sensing surface was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric detection of hydrogen peroxide was investigated by holding the modified electrode at −0.30 V (vs. Ag/AgCl). The biosensor showed optimum response within 5 s at pH 7.0. The optimized biosensor showed linear response range of 7.4 × 10−7–1.9 × 10−5 M with a detection limit of 7.4 × 10−7. The applicability of the purposed biosensor was tested by detecting hydrogen peroxide in disinfector samples. The average recovery was calculated as 100.78 ± 0.89

  8. Green synthesis of carbon-supported nanoparticle catalysts by physical vapor deposition on soluble powder substrates

    Science.gov (United States)

    Park, Hee-Young; Jang, Injoon; Jung, Namgee; Chung, Young-Hoon; Ryu, Jae Yoon; Cha, In Young; Kim, Hyung Juhn; Jang, Jong Hyung; Yoo, Sung Jong

    2015-09-01

    Metal and metal oxide nanoparticles (NPs) supported on high surface area carbon (NP/Cs) were prepared by the physical vapor deposition of bulk materials on an α-D-glucose (Glu) substrate, followed by the deposition of the NPs on carbon supports. Using Glu as a carrier for the transport of NPs from the bulk materials to the carbon support surfaces, ultrafine NPs were obtained, exhibiting a stabilizing effect through OH moieties on the Glu surfaces. This stabilizing effect was strong enough to stabilize the NPs, but weak enough to not significantly block the metal surfaces. As only the target materials and Glu are required in our procedure, it can be considered environmentally friendly, with the NPs being devoid of hazardous chemicals. Furthermore, the resulting NP/Cs exhibited an improvement in activity for various electrochemical reactions, mainly attributed to their high surface area.

  9. Investigating the growth mechanism and optical properties of carbon-coated titanium dioxide nanoparticles

    KAUST Repository

    Anjum, Dalaver H.

    2013-10-01

    TiO2 nanoparticles (NPs) were prepared using flame synthesis and then characterized using transmission electron microscopy. We found that the flame method yields both crystalline TiO2 and amorphous TiO 2 NPs. TEM analysis revealed that only the crystalline TiO 2 NPs were coated with carbon. Based on this observation, we proposed a growth model for the diffusion and precipitation of carbon atoms in TiO 2 NPs. The optical properties of TiO2 NPs were investigated by performing valence electron energy loss spectrometry analysis. We observed that carbon-coated TiO2 NPs have higher absorption in the visible range due to their lower band-gap energy. © 2013 Elsevier B.V.

  10. Thermodynamics of a phase transition of silicon nanoparticles at the annealing and carbonization of porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Nagornov, Yu. S., E-mail: Nagornov.Yuri@gmail.com [Togliatti State University (Russian Federation)

    2015-12-15

    The formation of SiC nanocrystals of the cubic modification in the process of high-temperature carbonization of porous silicon has been analyzed. A thermodynamic model has been proposed to describe the experimental data obtained by atomic-force microscopy, Raman scattering, spectral analysis, Auger spectroscopy, and X-ray diffraction spectroscopy. It has been shown that the surface energy of silicon nanoparticles and quantum filaments is released in the process of annealing and carbonization. The Monte Carlo simulation has shown that the released energy makes it possible to overcome the nucleation barrier and to form SiC nanocrystals. The processes of laser annealing and electron irradiation of carbonized porous silicon have been analyzed.

  11. Electrochemical activity and durability of platinum nanoparticles supported on ordered mesoporous carbons for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shou-Heng [Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617 (China); Chiang, Chien-Chang; Wu, Min-Tsung; Liu, Shang-Bin [Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617 (China); Department of Chemistry, National Taiwan Normal University, Taipei 11677 (China)

    2010-08-15

    A facile procedure for synthesizing platinum nanoparticles (NPs) studded in ordered mesoporous carbons (Pt-OMCs) based on the organic-organic self-assembly (one-pot) approach is reported. These Pt-OMCs, which can be easily fabricated with controllable Pt loading, were found to possess high surface areas, highly accessible and stable active sites and superior electrocatalytic properties pertinent as cathode catalysts for hydrogen-oxygen fuel cells. The enhanced catalytic activity and durability observed for the Pt-OMC electrocatalysts are attributed to the strengthened interactions between the Pt catalyst and the mesoporous carbon that effectively precludes migration and/or agglomeration of Pt NPs on the carbon support. (author)

  12. Thermodynamics of a phase transition of silicon nanoparticles at the annealing and carbonization of porous silicon

    International Nuclear Information System (INIS)

    The formation of SiC nanocrystals of the cubic modification in the process of high-temperature carbonization of porous silicon has been analyzed. A thermodynamic model has been proposed to describe the experimental data obtained by atomic-force microscopy, Raman scattering, spectral analysis, Auger spectroscopy, and X-ray diffraction spectroscopy. It has been shown that the surface energy of silicon nanoparticles and quantum filaments is released in the process of annealing and carbonization. The Monte Carlo simulation has shown that the released energy makes it possible to overcome the nucleation barrier and to form SiC nanocrystals. The processes of laser annealing and electron irradiation of carbonized porous silicon have been analyzed

  13. Pd nanoparticles supported on phenanthroline modified carbon as high active electrocatalyst for ethylene glycol oxidation

    International Nuclear Information System (INIS)

    Highlights: • Phenanthroline as nitrogen source to modify traditional carbon support. • Synthesized a novel catalyst of Pd supported on PMC. • Pd/PMC catalyst shows excellent activity and stability. - Abstract: Modified carbon is fabricated by applying phenanthroline as nitrogen source and used as support (PMC) to immobilize Pd nanoparticles. Because the nitrogen-doping not only changes physicochemical and electronic properties of carbon but also serves as basic or coordination sites to stabilize and produce additional electronic activation for Pd, the Pd/PMC exhibits excellent electrochemcial performance for ethylene glycol oxidation. Compared to conventional Pd/C catalyst, the Pd/PMC catalyst has a larger electrochemically active surface area, 50 mV more negative onset potential, 1.77 times oxidation current and superior stability

  14. Bioaccumulation and toxicity of CuO nanoparticles by a freshwater invertebrate after waterborne and dietborne exposures

    Science.gov (United States)

    Croteau, Marie-Noele; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2014-01-01

    The incidental ingestion of engineered nanoparticles (NPs) can be an important route of uptake for aquatic organisms. Yet, knowledge of dietary bioavailability and toxicity of NPs is scarce. Here we used isotopically modified copper oxide (65CuO) NPs to characterize the processes governing their bioaccumulation in a freshwater snail after waterborne and dietborne exposures. Lymnaea stagnalis efficiently accumulated 65Cu after aqueous and dietary exposures to 65CuO NPs. Cu assimilation efficiency and feeding rates averaged 83% and 0.61 g g–1 d–1 at low exposure concentrations (–1), and declined by nearly 50% above this concentration. We estimated that 80–90% of the bioaccumulated 65Cu concentration in L. stagnalis originated from the 65CuO NPs, suggesting that dissolution had a negligible influence on Cu uptake from the NPs under our experimental conditions. The physiological loss of 65Cu incorporated into tissues after exposures to 65CuO NPs was rapid over the first days of depuration and not detectable thereafter. As a result, large Cu body concentrations are expected in L. stagnalis after exposure to CuO NPs. To the degree that there is a link between bioaccumulation and toxicity, dietborne exposures to CuO NPs are likely to elicit adverse effects more readily than waterborne exposures.

  15. Differential regulation of intracellular factors mediating cell cycle, DNA repair and inflammation following exposure to silver nanoparticles in human cells

    Directory of Open Access Journals (Sweden)

    AshaRani PV

    2012-02-01

    Full Text Available Abstract Background Investigating the cellular and molecular signatures in eukaryotic cells following exposure to nanoparticles will further our understanding on the mechanisms mediating nanoparticle induced effects. This study illustrates the molecular effects of silver nanoparticles (Ag-np in normal human lung cells, IMR-90 and human brain cancer cells, U251 with emphasis on gene expression, induction of inflammatory mediators and the interaction of Ag-np with cytosolic proteins. Results We report that silver nanoparticles are capable of adsorbing cytosolic proteins on their surface that may influence the function of intracellular factors. Gene and protein expression profiles of Ag-np exposed cells revealed up regulation of many DNA damage response genes such as Gadd 45 in both the cell types and ATR in cancer cells. Moreover, down regulation of genes necessary for cell cycle progression (cyclin B and cyclin E and DNA damage response/repair (XRCC1 and 3, FEN1, RAD51C, RPA1 was observed in both the cell lines. Double strand DNA damage was observed in a dose dependant manner as evidenced in γH2AX foci assay. There was a down regulation of p53 and PCNA in treated cells. Cancer cells in particular showed a concentration dependant increase in phosphorylated p53 accompanied by the cleavage of caspase 3 and PARP. Our results demonstrate the involvement of NFκB and MAP kinase pathway in response to Ag-np exposure. Up regulation of pro-inflammatory cytokines such as interleukins (IL-8, IL-6, macrophage colony stimulating factor, macrophage inflammatory protein in fibroblasts following Ag-np exposure were also observed. Conclusion In summary, Ag-np can modulate gene expression and protein functions in IMR-90 cells and U251 cells, leading to defective DNA repair, proliferation arrest and inflammatory response. The observed changes could also be due to its capability to adsorb cytosolic proteins on its surface.

  16. Visualization of Carbon Nanoparticles Within Cells and Implications for Toxicity

    Science.gov (United States)

    Porter, Alexandra; Gass, Mhairi

    Carbon nanostructures (CNS), such as C60, single-walled nanotubes (SWNTs) exhibit extraordinary properties and are one of the most commercially relevant class of NS. CNS have already found uses in high-performance sports equipment (nanotubes) and face cream (C60), whilst potential applications include optical and electronic materials and superconductors. Following the huge growth in these nanotechnology-related industries, significant concerns have arisen about their potential toxicity and impact on the environment. A lack in understanding of the interaction of such small structures with cellular material has resulted in concerns over their impact on human health. The potential toxicity of CNS and safety to human health requires an understanding of their interaction with cells and this in turn relies on the measurement of the pathways by which they enter the cell, their spatial distribution within and whether the CNS are transformed by the action of the cell; visualization of intracellular CNS is therefore imperative. However visualizing unlabelled CNS within cells is demanding because it is difficult to distinguish CNS from carbon-rich organelles given their similarity in composition and dimensions. In particular, the challenge lies in translating analytical imaging tools developed for inorganic systems to organic systems. This chapter describes how the state-of-the-art transmission electron microscopy (TEM) techniques, such as low-loss energy-filtered TEM (EFTEM) can be employed to differentiate between unlabelled C60, SWNTs and the cell. Further, we demonstrate how these techniques can be used to trace the uptake of CNS into the cell and to assess their localized effects on cell structure.

  17. Synergy between Printex nano-carbons and silver nanoparticles for sensitive estimation of antioxidant activity.

    Science.gov (United States)

    Raymundo-Pereira, Paulo A; Campos, Anderson M; Prado, Thiago M; Furini, Leonardo N; Boas, Naiza V; Calegaro, Marcelo L; Machado, Sergio A S

    2016-07-01

    We report on the synthesis, characterization and applications of a Printex L6 carbon-silver hybrid nanomaterial (PC-Ag), which was obtained using a polyol method. In addition, we also highlight the use of Printex L6 nano-carbon as a much cheaper alternative to the use of carbon nanotubes and graphene. The silver nanoparticles (AgNP) were prepared directly on the surface of the Printex 6L carbon "nanocarbon" material using ethylene glycol as the reducing agent. The hybrid nanomaterial was characterized by High-angle annular dark-field transmission electron microscopy (HAADF-TEM), energy-dispersive X-ray spectroscopy (EDX), selected area electron diffraction (SAED), Raman spectroscopy and cyclic voltammetry. Optimized electrocatalytic activity on glassy carbon electrode was reached for the architecture GC/PC-Ag, the silver nanoparticles with size ranging between 1 and 2 nm were well-distributed throughout the hybrid material. The synergy between PC nano-carbons and AgNPs was verified by detection of gallic acid (GA) at a low applied potential (0.091 V vs. Ag/AgCl). GA detection was performed in a concentration range between 5.0 × 10(-7) and 8.5 × 10(-6) mol L(-1), with a detection limit of 6.63 × 10(-8) mol L(-1) (66.3 nmol L(-1)), which is considerably lower than similar devices. The approach for fabricating the reproducible GC/PC-Ag electrodes is entirely generic and may be explored for other types of (bio)sensors and devices. PMID:27216397

  18. Mechanical performance of styrene-butadiene-rubber filled with carbon nanoparticles prepared by mechanical mixing

    International Nuclear Information System (INIS)

    Highlights: → We compare influence of carbon blacks and carbon nanotube on properties of SBR. → We model mechanical behavior of SBR nanocomposites by the micromechanical model. → Mechanical properties of carbon black/SBR is greatly dominated by bound rubber. → Mechanical properties of SBR/nanotube is governed by big aspect ratio of nanotube. - Abstract: Reinforcement of styrene-butadiene-rubber (SBR) was investigated using two different carbon blacks (CBs) with similar particle sizes, including highly structured CB and conventional CB, as well as multi-walled carbon nanotube (MWCNT) prepared by mechanical mixing. The attempts were made to examine reinforcing mechanism of these two different classes of carbon nanoparticles. Scanning electron microscopy and electrical conductivity measurement were used to investigate morphology. Tensile, cyclic tensile and stress relaxation analyses were performed. A modified Halpin-Tsai model based on the concept of an equivalent composite particle, consisting of rubber bound, occluded rubber and nanoparticle, was proposed. It was found that properties of CB filled SBR are significantly dominated by rubber shell and occluded rubber in which molecular mobility is strictly restricted. At low strains, these rubber constituents can contribute in hydrodynamic effects, leading to higher elastic modulus. However, at higher strains, they contribute in stress hardening resulting in higher elongation at break and higher tensile strength. These elastomeric regions can also influence stress relaxation behaviors of CB filled rubber. For SBR/MWCNT, the extremely great inherent mechanical properties of nanotube along with its big aspect ratio were postulated to be responsible for the reinforcement while their interfacial interaction was not so efficient.

  19. Occupational exposure to airborne nanomaterials: An assessment of worker exposure to aerosolized metal oxide nanoparticles in a semiconductor fab and subfab.

    Science.gov (United States)

    Brenner, Sara A; Neu-Baker, Nicole M; Caglayan, Cihan; Zurbenko, Igor G

    2016-09-01

    This occupational exposure assessment study characterized potential inhalation exposures of workers to engineered nanomaterials associated with chemical mechanical planarization wafer polishing processes in a semiconductor research and development facility. Air sampling methodology was designed to capture airborne metal oxide nanoparticles for characterization. The research team obtained air samples in the fab and subfab areas using a combination of filter-based capture methods to determine particle morphology and elemental composition and real-time direct-reading instruments to determine airborne particle counts. Filter-based samples were analyzed by electron microscopy and energy-dispersive x-ray spectroscopy while real-time particle counting data underwent statistical analysis. Sampling was conducted during worker tasks associated with preventive maintenance and quality control that were identified as having medium to high potential for inhalation exposure based on qualitative assessments. For each sampling event, data was collected for comparison between the background, task area, and personal breathing zone. Sampling conducted over nine months included five discrete sampling series events in coordination with on-site employees under real working conditions. The number of filter-based samples captured was: eight from worker personal breathing zones; seven from task areas; and five from backgrounds. A complementary suite of direct-reading instruments collected data for seven sample collection periods in the task area and six in the background. Engineered nanomaterials of interest (Si, Al, Ce) were identified in filter-based samples from all areas of collection, existing as agglomerates (>500 nm) and nanoparticles (100-500 nm). Particle counts showed an increase in number concentration above background during a subset of the job tasks, but particle counts in the task areas were otherwise not significantly higher than background. Additional data is needed to

  20. Hemocyte responses of Dreissena polymorpha following a short-term in vivo exposure to titanium dioxide nanoparticles: Preliminary investigations

    Energy Technology Data Exchange (ETDEWEB)

    Couleau, Nicolas; Techer, Didier [Universite de Lorraine, Laboratoire des Interactions Ecotoxicologie, Biodiversite, Ecosystemes (LIEBE), CNRS UMR 7146, IUT Thionville-Yutz, Espace Cormontaigne, Yutz, F-57970 (France); Pagnout, Christophe [Universite de Lorraine, Laboratoire des Interactions Ecotoxicologie, Biodiversite, Ecosystemes (LIEBE), UMR 7146, Campus Bridoux, rue du General Delestraint, Metz, F-57070 (France); International Consortium for the Environmental Implications of Nanotechnology, iCEINT, http://www.i-ceint.org (France); Jomini, Stephane [Universite de Lorraine, Laboratoire des Interactions Ecotoxicologie, Biodiversite, Ecosystemes (LIEBE), UMR 7146, Campus Bridoux, rue du General Delestraint, Metz, F-57070 (France); Foucaud, Laurent; Laval-Gilly, Philippe; Falla, Jairo [Universite de Lorraine, Laboratoire des Interactions Ecotoxicologie, Biodiversite, Ecosystemes (LIEBE), CNRS UMR 7146, IUT Thionville-Yutz, Espace Cormontaigne, Yutz, F-57970 (France); Bennasroune, Amar, E-mail: amar.bennasroune@univ-metz.fr [Universite de Lorraine, Laboratoire des Interactions Ecotoxicologie, Biodiversite, Ecosystemes (LIEBE), CNRS UMR 7146, IUT Thionville-Yutz, Espace Cormontaigne, Yutz, F-57970 (France)

    2012-11-01

    The widespread use of titanium-based nanoparticles and their environmental release may pose a significant risk to aquatic organisms within freshwater ecosystems. Suspension-feeder invertebrates like bivalve molluscs represent a unique target group for nanoparticle toxicology. The aim of this work was to investigate the short-term responses of Dreissena polymorpha hemocytes after in vivo exposure to titanium dioxide nanoparticles (TiO{sub 2} NP). For this purpose, freshwater mussels were exposed to P25 TiO{sub 2} NP at the concentrations of 0.1, 1, 5 and 25 mg/L during 24 h. Viability, phagocytosis activity and mitogen activated protein kinase (MAPK) phosphorylation level of ERK 1/2 and p38 in hemocytes extracted from exposed mussels were compared to those from control specimens. Results demonstrated an inhibition of the phagocytosis activity after exposure to TiO{sub 2} NP at 0.1 and 1 mg/L. Similar trends, albeit less pronounced, were reported for higher concentrations of NP. Transmission electron microscopy showed for the first time the internalization of TiO{sub 2} NP into Dreissena polymorpha hemocytes. Besides, exposure to NP increased the ERK 1/2 phosphorylation levels in all treatments. Concerning the phosphorylation level of p38, only exposures to 5 and 25 mg/L of NP induced significant p38 activation in comparison to that of the control. Finally, these short-term effects observed at environmentally relevant concentrations highlighted the need for further studies concerning ecotoxicological evaluation of nanoparticle release into an aquatic environment. -- Highlights: Black-Right-Pointing-Pointer Phagocytosis inhibition at TiO{sub 2} NP exposure concentrations of 0.1 and 1 mg/L. Black-Right-Pointing-Pointer Internalization of TiO{sub 2} NP in freshwater mussel hemocytes. Black-Right-Pointing-Pointer Increased phosphorylation level of p38 and ERK 1/2 after in vivo exposure to TiO{sub 2} NP.

  1. Morphokinetics of mesenterial lymphatic node cell populations in exposure of gold nanoparticles within experimental work

    Directory of Open Access Journals (Sweden)

    Dykman L.A.

    2011-06-01

    Full Text Available The research goal is to investigate the influence of gold nanoparticles with different size (1-3 nm, 15 nm and 50 nm on the morphokinetics of mesenterial lymphatic node cell populations of healthy laboratory animals. Experiment included 24 white rats. The investigation was conducted in 4 groups of animals. The animals were administered the gold nanoparticles orally for 15 days. It was established that the oral administration of gold nanoparticles caused the changes of morphokinetics of mesenterial lymphatic node cell populations. The morphological alterations in the mesenterial lymphatic nodes assisted in activation of migration processes, the proliferation and differentiation. The immu-nomodulatory action of gold nanoparticles was proved

  2. Macroporous carbon decorated with dendritic platinum nanoparticles: one-step synthesis and electrocatalytic properties

    Science.gov (United States)

    Yu, Xueqing; Zhang, Yufan; Guo, Liping; Wang, Liang

    2014-04-01

    Macroporous carbon (MPC) with high pore accessibility and electrical conductivity is of great interest to the electrochemical platform. The development of a simple and efficient route for the direct synthesis of dendritic platinum nanoparticle (DPN) decorated MPC (DPN/MPC) is an interesting challenge, which is highly valuable for electrocatalytic applications. In this study, we propose a very simple route for the one-step synthesis of DPN/MPC in aqueous solution at room temperature without the need for any kind of seed and surfactant to direct the dendritic growth of Pt nanoparticles, which is performed by simply mixing an aqueous solution of K2PtCl4 with MPC and formic acid. The as-prepared DPN/MPC shows high electrocatalytic activities toward the oxidation of methanol and glucose.

  3. Electrodeposited gold nanoparticles on carbon nanotube-textile: Anode material for glucose alkaline fuel cells

    KAUST Repository

    Pasta, Mauro

    2012-06-01

    In the present paper we propose a new anode material for glucose-gluconate direct oxidation fuel cells prepared by electrodepositing gold nanoparticles onto a conductive textile made by conformally coating single walled carbon nanotubes (SWNT) on a polyester textile substrate. The electrodeposition conditions were optimized in order to achieve a uniform distribution of gold nanoparticles in the 3D porous structure of the textile. On the basis of previously reported studies, the reaction conditions (pH, electrolyte composition and glucose concentration) were tuned in order to achieve the highest oxidation rate, selectively oxidizing glucose to gluconate. The electrochemical characterization was carried out by means of cyclic voltammetry. © 2012 Elsevier B.V. All rights reserved.

  4. Carbon nanofiber supported bimetallic PdAu nanoparticles for formic acid electrooxidation

    Science.gov (United States)

    Qin, Yuan-Hang; Jiang, Yue; Niu, Dong-Fang; Zhang, Xin-Sheng; Zhou, Xing-Gui; Niu, Li; Yuan, Wei-Kang

    2012-10-01

    Carbon nanofiber (CNF) supported PdAu nanoparticles are synthesized with sodium citrate as the stabilizing agent and sodium borohydride as the reducing agent. High resolution transmission electron microscopy (HRTEM) characterization indicates that the synthesized PdAu particles are well dispersed on the CNF surface and X-ray diffraction (XRD) characterization indicates that the alloying degree of the synthesized PdAu nanoparticles can be improved by adding tetrahydrofuran to the synthesis solution. The results of electrochemical characterization indicate that the addition of Au can promote the electrocatalytic activity of Pd/C catalyst for formic acid oxidation and the CNF supported high-alloying PdAu catalyst possesses better electrocatalytic activity and stability for formic acid oxidation than either the CNF supported low-alloying PdAu catalyst or the CNF supported Pd catalyst.

  5. Physiological hepatic response to zinc oxide nanoparticle exposure in the white sucker, Catostomus commersonii.

    Science.gov (United States)

    Dieni, Christopher Anthony; Callaghan, Neal Ingraham; Gormley, Patrick Thomas; Butler, Kathryn Marie Alison; Maccormack, Tyson James

    2014-05-01

    Liver toxicity of commercially relevant zinc oxide nanoparticles (nZnO) was assessed in a benthic freshwater cypriniform, the white sucker (Catostomus commersonii). Exposure to nZnO caused several changes in levels of liver enzyme activity, antioxidants, and lipid peroxidation end products consistent with an oxidative stress response. Aconitase activity decreased by ~65% but tended to be restored to original levels upon supplementation with Fe(2+), indicating oxidative inactivation of the 4Fe-4S cluster. Furthermore, glucose-6-phosphate dehydrogenase activity decreased by ~29%, and glutathione levels increased by ~56%. Taken together, these suggest that nZnO induces hepatic physiological stress. Each assay was then validated by using a single liver homogenate or plasma sample that was partitioned and treated with nZnO or Zn(2+), the breakdown product of nZnO. It was found that Zn(2+), but not nZnO, increased detected glutathione reductase activity by ~14% and decreased detected malondialdehyde by ~39%. This indicates that if appreciable nZnO dissolution occurs in liver samples during processing and assay, it may skew results, with implications not only for this study, but also for a wide range of nanotoxicology studies focusing on nZnO. Finally, in vitro incubations of cell-free rat blood plasma with nZnO failed to generate any significant increase in malondialdehyde or protein carbonyl levels, or any significant decrease in ferric reducing ability of plasma. This suggests that at the level tested, any oxidative stress caused by nZnO is the result of a coordinated physiological response by the liver. PMID:24704545

  6. Bioavailability and biodistribution of differently charged polystyrene nanoparticles upon oral exposure in rats

    International Nuclear Information System (INIS)

    The likelihood of oral exposure to nanoparticles (NPs) is increasing, and it is necessary to evaluate the oral bioavailability of NPs. In vitro approaches could help reducing animal studies, but validation against in vivo studies is essential. Previously, we assessed the translocation of 50 nm polystyrene NPs of different charges (neutral, positive and negative) using a Caco-2/HT29-MTX in vitro intestinal translocation model. The NPs translocated in a surface charge-dependent manner. The present study aimed to validate this in vitro intestinal model by an in vivo study. For this, rats were orally exposed to a single dose of these polystyrene NPs and the uptake in organs was determined. A negatively charged NP was taken up more than other NPs, with the highest amounts in kidney (37.4 µg/g tissue), heart (52.8 µg/g tissue), stomach wall (98.3 µg/g tissue) and small intestinal wall (94.4 µg/g tissue). This partly confirms our in vitro findings, where the same NPs translocated to the highest extent. The estimated bioavailability of different types of NPs ranged from 0.2 to 1.7 % in vivo, which was much lower than in vitro (1.6–12.3 %). Therefore, the integrated in vitro model cannot be used for a direct prediction of the bioavailability of orally administered NPs. However, the model can be used for prioritizing NPs before further in vivo testing for risk assessment

  7. Bioavailability and biodistribution of differently charged polystyrene nanoparticles upon oral exposure in rats

    Energy Technology Data Exchange (ETDEWEB)

    Walczak, Agata P. [Wageningen University, Division of Toxicology (Netherlands); Hendriksen, Peter J. M. [RIKILT Wageningen UR (Netherlands); Woutersen, Ruud A. [TNO Earth, Life and Social Sciences (Netherlands); Zande, Meike van der; Undas, Anna K.; Helsdingen, Richard [RIKILT Wageningen UR (Netherlands); Berg, Hans H. J. van den; Rietjens, Ivonne M. C. M. [Wageningen University, Division of Toxicology (Netherlands); Bouwmeester, Hans, E-mail: hans.bouwmeester@wur.nl [RIKILT Wageningen UR (Netherlands)

    2015-05-15

    The likelihood of oral exposure to nanoparticles (NPs) is increasing, and it is necessary to evaluate the oral bioavailability of NPs. In vitro approaches could help reducing animal studies, but validation against in vivo studies is essential. Previously, we assessed the translocation of 50 nm polystyrene NPs of different charges (neutral, positive and negative) using a Caco-2/HT29-MTX in vitro intestinal translocation model. The NPs translocated in a surface charge-dependent manner. The present study aimed to validate this in vitro intestinal model by an in vivo study. For this, rats were orally exposed to a single dose of these polystyrene NPs and the uptake in organs was determined. A negatively charged NP was taken up more than other NPs, with the highest amounts in kidney (37.4 µg/g tissue), heart (52.8 µg/g tissue), stomach wall (98.3 µg/g tissue) and small intestinal wall (94.4 µg/g tissue). This partly confirms our in vitro findings, where the same NPs translocated to the highest extent. The estimated bioavailability of different types of NPs ranged from 0.2 to 1.7 % in vivo, which was much lower than in vitro (1.6–12.3 %). Therefore, the integrated in vitro model cannot be used for a direct prediction of the bioavailability of orally administered NPs. However, the model can be used for prioritizing NPs before further in vivo testing for risk assessment.

  8. Synergistic bactericidal effect by combined exposure to Ag nanoparticles and UVA

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaoxu; Toyooka, Tatsushi; Ibuki, Yuko, E-mail: ibuki@u-shizuoka-ken.ac.jp

    2013-08-01

    Broad and strong antimicrobial properties of silver (Ag) have been used for biomedical applications, water treatment, etc. In this study, a synergistic antibacterial effect between Ag nanoparticles (AgNPs) and ultraviolet (UV) light was examined. AgNPs (< 0.1 μm) with subsequent exposure to UVA (320–400 nm) showed pronounced toxicity in Escherichia coli, but micro-sized Ag particles (> 1 μm) with UVA and AgNPs with UVB (280–325 nm) did not. As significant bactericidal activity was also exhibited by hydrogen peroxide-treated AgNPs, the surface oxidation of AgNPs caused by UVA irradiation was considered to contribute to the enhanced antibacterial effect. Although no difference in NP-incorporation rates was observed with or without the surface oxidation of AgNPs, a particle size of less than 0.1 μm was a factor for AgNPs uptake and an essential requirement for the antimicrobial function of Ag particles. Incorporated AgNPs oxidized by UVA irradiation released larger amounts of Ag ion inside cells than reduced AgNPs, which reacted with intercellular molecules having –SH groups such as glutathione. The synergistic use of AgNPs and UVA could become a powerful tool with broad antimicrobial applications. Highlights: • Combined treatment with AgNPs and UV achieved a remarkable antibacterial effect in E. coli. • For the antibacterial effect, it is necessary to satisfy the following requirements: • 1) Translocation of nano-sized Ag particles inside E. coli. • 2) Oxidation of AgNPs by UVA, and extensive and persistent release of Ag{sup +} inside E. coli. • Ag{sup +} released inside cells reacted with intercellular molecules having –SH groups such as GSH.

  9. Synthesis of carbon-supported titanium oxynitride nanoparticles as cathode catalyst for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Highlights: • A sol–gel route for the synthesis of rutile TiO2 was modified to synthesize TiOxNy-C. • N atoms were doped into TiOx nanoparticles solely by the heat-treatment under N2 gas. • The N2-treatment produced sites more active toward ORR compared with NH3-treatment. • TiOx doped with a small amount of N atoms are suggested to be responsible for ORR. -- Abstract: For use as the oxygen reduction reaction (ORR) catalyst in polymer electrolyte fuel cell cathodes, carbon-supported titanium oxynitride (TiOxNy-C) nanoparticles with a size of approximately 5 nm or less were synthesized without using NH3 gas. A sol–gel route developed for the synthesis of pure rutile TiO2 nanopowders was modified to prepare the carbon-supported titanium oxide nanoparticles (TiOx-C). For the first time, N atoms were doped into TiOx solely by heating TiOx-C under an inexpensive N2 atmosphere at 873 K for 3 h, which could be due to carbothermal reduction. The TiOx-C powder was also heated under NH3 gas at various temperatures (873–1273 K) and durations (3–30 h). This step resulted in the formation of a TiN phase irrespective of the heating conditions. Both N2- and NH3-treated TiOxNy-C did not crystallize well; however, the former showed a mass activity more than three times larger than that of the latter at 0.74 V versus the standard hydrogen electrode. Thus, titanium oxide nanoparticles doped with a small amount of N atoms are suggested to be responsible for catalyzing ORR in the case of N2-treated TiOxNy-C

  10. Occupational dermal exposure to nanoparticles and nano-enabled products: Part I-Factors affecting skin absorption.

    Science.gov (United States)

    Larese Filon, Francesca; Bello, Dhimiter; Cherrie, John W; Sleeuwenhoek, Anne; Spaan, Suzanne; Brouwer, Derk H

    2016-08-01

    The paper reviews and critically assesses the evidence on the relevance of various skin uptake pathways for engineered nanoparticles, nano-objects, their agglomerates and aggregates (NOAA). It focuses especially in occupational settings, in the context of nanotoxicology, risk assessment, occupational medicine, medical/epidemiological surveillance efforts, and the development of relevant exposure assessment strategies. Skin uptake of nanoparticles is presented in the context of local and systemic health effects, especially contact dermatitis, skin barrier integrity, physico-chemical properties of NOAA, and predisposing risk factors, such as stratum corneum disruption due to occupational co-exposure to chemicals, and the presence of occupational skin diseases. Attention should be given to: (1) Metal NOAA, since the potential release of ions may induce local skin effects (e.g. irritation and contact dermatitis) and absorption of toxic or sensitizing metals; (2) NOAA with metal catalytic residue, since potential release of ions may also induce local skin effects and absorption of toxic metals; (3) rigid NOAA smaller than 45nm that can penetrate and permeate the skin; (4) non rigid or flexible NOAA, where due to their flexibility liposomes and micelles can penetrate and permeate the intact skin; (5) impaired skin condition of exposed workers. Furthermore, we outline possible situations where health surveillance could be appropriate where there is NOAA occupational skin exposures, e.g. when working with nanoparticles made of sensitizer metals, NOAA containing sensitizer impurities, and/or in occupations with a high prevalence of disrupted skin barrier integrity. The paper furthermore recommends a stepwise approach to evaluate risk related to NOAA to be applied in occupational exposure and risk assessment, and discusses implications related to health surveillance, labelling, and risk communication. PMID:27289581

  11. A population-based exposure assessment methodology for carbon monoxide: Development of a carbon monoxide passive sampler and occupational dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Apte, M.G.

    1997-09-01

    Two devices, an occupational carbon monoxide (CO) dosimeter (LOCD), and an indoor air quality (IAQ) passive sampler were developed for use in population-based CO exposure assessment studies. CO exposure is a serious public health problem in the U.S., causing both morbidity and mortality (lifetime mortality risk approximately 10{sup -4}). Sparse data from population-based CO exposure assessments indicate that approximately 10% of the U.S. population is exposed to CO above the national ambient air quality standard. No CO exposure measurement technology is presently available for affordable population-based CO exposure assessment studies. The LOCD and IAQ Passive Sampler were tested in the laboratory and field. The palladium-molybdenum based CO sensor was designed into a compact diffusion tube sampler that can be worn. Time-weighted-average (TWA) CO exposure of the device is quantified by a simple spectrophotometric measurement. The LOCD and IAQ Passive Sampler were tested over an exposure range of 40 to 700 ppm-hours and 200 to 4200 ppm-hours, respectively. Both devices were capable of measuring precisely (relative standard deviation <20%), with low bias (<10%). The LOCD was screened for interferences by temperature, humidity, and organic and inorganic gases. Temperature effects were small in the range of 10{degrees}C to 30{degrees}C. Humidity effects were low between 20% and 90% RH. Ethylene (200 ppm) caused a positive interference and nitric oxide (50 ppm) caused a negative response without the presence of CO but not with CO.

  12. Decorating multiwalled carbon nanotubes with zinc oxide nanoparticles by thermally decomposing Zn-oleate in an organic medium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Carbon nanotubes decorated with zinc oxide nanoparticles were produced by thermally decomposing a Zn-oleate complex in an octadecene medium.The structure of the ZnO decorating nanotube surfaces was characterized by transmission electron microscopy,scanning electron microscopy and X-ray dif-fraction.The surfaces were shown to be densely and homogeneously covered by ZnO nanoparticles with a size below 10 nm.The nanoparticles had the wurtzite hexagonal crystal structure and showed good adhesion to the nanotubes.The carbon nanotubes decorated by metal oxide nanoparticles were synthesized at relatively low temperature and non-oxidation environment.Moreover,the large-scale production with low cost can be realized.

  13. Simultaneous deposition of carbon nanotubes and decoration with gold-palladium nanoparticles by laser-induced forward transfer

    Science.gov (United States)

    Lasserre, Federico; Rosenkranz, Andreas; Souza Carmona, Nicolás; Roble, Martín; Ramos-Moore, Esteban; Diaz-Droguett, Donovan E.; Mücklich, Frank

    2016-03-01

    Decorating carbon nanotubes (CNTs) with nanoparticles has proved to be an intelligent approach to improve the gas adsorption properties of CNTs for the development of new sensors, including hydrogen sensors. However, in order to take advantage of this hybrid structure, methods are needed that ensure a proper decoration and the fabrication of small features without compromising the sensing surface. Within this paper, we report a novel technique to simultaneously decorate multiwall carbon nanotubes (MWCNTs) with gold-palladium nanoparticles and transfer them to a substrate by laser-induced forward transfer using femtosecond laser pulses. The nanoparticles decorating the MWCNTs present a spherical shape with a Feret diameter bellow 200 nm. The nanoparticle size can be tuned by varying the amount of pulses within the transfer. Finally, hydrogen adsorption showed up to a 20-fold increase compared to a sample composed of non-transferred, non-decorated MWCNTs.

  14. Decorating multiwalled carbon nanotubes with zinc oxide nanoparticles by thermally decomposing Zn-oleate in an organic medium

    Institute of Scientific and Technical Information of China (English)

    LI ChenSha; QIAO YingJie; LI YuNing; WU YiLiang

    2009-01-01

    Carbon nanotubes decorated with zinc oxide nanoparticles were produced by thermally decomposing a Zn-oleate complex in an octadecene medium. The structure of the ZnO decorating nanotube surfaces was characterized by transmission electron microscopy, scanning electron microscopy and X-ray dif-fraction. The surfaces were shown to be densely and homogeneously covered by ZnO nanoparticles with a size below 10 nm. The nanoparticles had the wurtzite hexagonal crystal structure and showed good adhesion to the nanotubes. The carbon nanotubes decorated by metal oxide nanoparticles were synthesized at relatively low temperature and non-oxidation environment. Moreover, the large-scale production with low cost can be realized.

  15. Thermal effects on Rhodium nanoparticles supported on carbon

    International Nuclear Information System (INIS)

    EXAFS measurements have been made in the temperature range 5 – 300 K on rhodium nano-clusters of average diameters 15.9 and 11.5 Å (rms dispersion 7.2 and 4.7 Å, respectively) supported on carbon, as well as on a Rh reference foil. The preliminary results of the first shell analysis are presented. The Debye temperature is slightly smaller in n-Rh with respect to bulk and decreases when the cluster size decreases. The results of amplitude analysis (coordination number and static DW) are sensitive to the inclusion of the 4th cumulant. In going from bulk Rh to n-Rh and decreasing the nanocluster size the average coordination number decreases and the static disorder increases. A contraction of the average nearest-neighbour distance is observed at 5 K, −0.004 Å and −0.009 Å for the larger and smaller clusters, respectively, accompanied by a very slight thermal expansion.

  16. Retention of silica nanoparticles on calcium carbonate sands immersed in electrolyte solutions

    KAUST Repository

    Li, Yan Vivian

    2014-12-01

    © 2014 Elsevier Inc. Understanding nanoparticle-surface adhesion is necessary to develop inert tracers for subsurface applications. Here we show that nanoparticles with neutral surface charge may make the best subsurface tracers, and that it may be possible to used SiO2 nanoparticle retention to measure the fraction of solid surface that has positive charge. We show that silica nanoparticles dispersed in NaCl electrolyte solutions are increasingly retained in calcium carbonate (calcite) sand-packed columns as the solution ionic strength increases, but are not retained if they are injected in pure water or Na2SO4 electrolyte solutions. The particles retained in the NaCl experiments are released when the column is flushed with pure water or Na2SO4 solution. AFM measurements on calcite immersed in NaCl solutions show the initial repulsion of a silica colloidal probe as the surface is approached is reduced as the solution ionic strength increases, and that at high ionic strengths it disappears entirely and only attraction remains. These AFM measurements and their interpretation with Derjaguin-Landau-Verwey-Overbeek (DLVO) theory shows the calcite surface charge is always negative for Na2SO4 solutions, but changes from negative to positive in a patchy fashion as the ionic strength of the NaCl solution increases. Since mixed-charge (patchy) surfaces may be common in the subsurface, nanoparticles with near-zero charge may make the best tracers.

  17. Molecular dynamics study of the stability of a carbon nanotube atop a catalytic nanoparticle

    CERN Document Server

    Verkhovtsev, Alexey V; Solov'yov, Andrey V

    2014-01-01

    The stability of a single-walled carbon nanotube placed on top of a catalytic nickel nanoparticle is investigated by means of molecular dynamics simulations. As a case study, we consider the $(12,0)$ nanotube consisting of 720 carbon atoms and the icosahedral Ni$_{309}$ cluster. An explicit set of constant-temperature simulations is performed in order to cover a broad temperature range from 400 to 1200 K, at which a successful growth of carbon nanotubes has been achieved experimentally by means of chemical vapor deposition. The stability of the system depending on parameters of the involved interatomic interactions is analyzed. It is demonstrated that different scenarios of the nanotube dynamics atop the nanoparticle are possible depending on the parameters of the Ni-C potential. When the interaction is weak the nanotube is stable and resembles its highly symmetric structure, while an increase of the interaction energy leads to the abrupt collapse of the nanotube in the initial stage of simulation. In order t...

  18. Antimony nanoparticles anchored in three-dimensional carbon network as promising sodium-ion battery anode

    Science.gov (United States)

    Luo, Wen; Zhang, Pengfei; Wang, Xuanpeng; Li, Qidong; Dong, Yifan; Hua, Jingchen; Zhou, Liang; Mai, Liqiang

    2016-02-01

    A novel composite with antimony (Sb) nanoparticles anchored in three-dimensional carbon network (denoted as SbNPs@3D-C) is successfully synthesized via a NaCl template-assisted self-assembly strategy, followed by freeze-drying and one-step in-situ carbonization. The three-dimensional interconnected macroporous carbon framework can not only stabilize the architecture and buffer the volume expansion for Sb nanoparticles, but also provide high electrical conductivity for the whole electrode. Consequently, as a sodium-ion battery anode, the SbNPs@3D-C delivers a high reversible capacity (456 mAh g-1 at 100 mA g-1), stable cycling performance (94.3% capacity retention after 500 cycles at 100 mA g-1) as well as superior rate capability (270 mAh g-1 at 2000 mA g-1). When compared with commercial Sb particles, the SbNPs@3D-C exhibits dramatically enhanced electrochemical performance. Free from expensive template sources and complex manipulation, this work might shed some light on the synthesis of low-cost and high-performance materials for the next "beyond lithium" battery generation.

  19. Unique Sandwiched Carbon Sheets@Ni-Mn Nanoparticles for Enhanced Oxygen Evolution Reaction.

    Science.gov (United States)

    Zhang, Yan; Zhang, Huijuan; Yang, Jiao; Bai, Yuanjuan; Qiu, Huajun; Wang, Yu

    2016-05-11

    A unique sandwich-like architecture, where Ni-Mn nanoparticles are enveloped in coupled carbon sheets (CS@Ni-Mn), has been successfully fabricated. In the synthesis process, a great quantity of uniform NiMnO3 nanosheets generated by a universal hydrothermal method acts as precursors and templates and the cheap, environmentally friendly and recyclable glucose functions as a green carbon source. Via subsequent hydrothermal reaction and thermal annealing, sandwiched nanocomposites with Ni-Mn nanoparticles embedded inside and carbon sheets encapsulating outside can be massively prepared. The novel sandwich-like CS@Ni-Mn possesses numerous advantages, such as an intrinsic porous feature, large specific surface area, and enhanced electronic conductivity. Moreover, as a promising NiMn-based oxygen evolution reaction (OER) catalyst, the special sandwiched nanostructure demonstrates improved electrochemical properties in 1 M KOH, including a low overpotential of about 250 mV, a modest Tafel slope of 40 mV dec(-1), excellent stability over 2000 cycles, and durability for 40 h. PMID:27101350

  20. X-ray photoelectron spectroscopic study of nitrogen incorporated amorphous carbon films embedded with nanoparticles

    International Nuclear Information System (INIS)

    The effect of substrate bias on X-ray photoelectron spectroscopy (XPS) study of nitrogen incorporated amorphous carbon (a-C:N) films embedded with nanoparticles deposited by filtered cathodic jet carbon arc technique is discussed. High resolution transmission electron microscope exhibited initially the amorphous structure but on closer examination the film was constituted of amorphous phase with the nanoparticle embedded in the amorphous matrix. X-ray diffraction study reveals dominantly an amorphous nature of the film. A straight forward method of deconvolution of XPS spectra has been used to evaluate the sp3 and sp2 contents present in these a-C:N films. The carbon (C 1s) peaks have been deconvoluted into four different peaks and nitrogen (N 1s) peaks have been deconvoluted into three different peaks which attribute to different bonding state between C, N and O. The full width at half maxima (FWHM) of C 1s peak, sp3 content and sp3/sp2 ratio of a-C:N films increase up to -150 V substrate bias and beyond -150 V substrate bias these parameters are found to decrease. Thus, the parameters evaluated are found to be dependent on the substrate bias which peaks at -150 V substrate bias.

  1. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    International Nuclear Information System (INIS)

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoSx (x≈4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoSx under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS2 materials with very high pore volume and specific surface area, up to 0.45 cm3/g and 190 m2/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoSx particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS2 with very high porosity and surface area

  2. Decoration of Silver Nanoparticles on Multiwalled Carbon Nanotubes: Antibacterial Mechanism and Ultrastructural Analysis

    Directory of Open Access Journals (Sweden)

    Ngo Xuan Dinh

    2015-01-01

    Full Text Available Recently, development of carbon nanocomposites composed of carbon nanostructures and metal nanoparticles has attracted much interests because of their large potential for technological applications such as catalyst, sensor, biomedicine, and disinfection. In this work, we established a simple chemistry method to synthesize multiwalled carbon nanotubes (MWCNTs decorated with silver nanoparticles (Ag-NPs using a modified photochemical reaction (Tollens process. The formation and interaction of Ag-NPs with functionalized groups on the surface of MWCNTs were analyzed by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The average size of Ag-NPs on the MWCNTs was approximately ~7 nm with nearly uniform size distribution. Antibacterial effect of Ag-MWCNTs nanocomposites was evaluated against two pathogenic bacteria including Gram-negative Escherichia Coli and Gram-positive Staphylococcus aureus bacteria. Interaction and bactericidal mechanism of Ag-MWCNTs with tested bacteria was studied by adapting the electron microscopy. Analysis on ultrastructural changes of bacterial cells indicates that antibacterial action mechanism of Ag-MWCNTs is physical interaction with cell membrane, the large formation of cell-Ag-MWCNTs aggregates, and faster destructibility of cell membrane and disruption of membrane function, hence resulting in cells death.

  3. Expeditious low-temperature sintering of copper nanoparticles with thin defective carbon shells

    Science.gov (United States)

    Kim, Changkyu; Lee, Gyoungja; Rhee, Changkyu; Lee, Minku

    2015-04-01

    The realization of air-stable nanoparticles, well-formulated nanoinks, and conductive patterns based on copper is a great challenge in low-cost and large-area flexible printed electronics. This work reports the synthesis of a conductively interconnected copper structure via thermal sintering of copper inks at a low temperature for a short period of time, with the help of thin defective carbon shells coated onto the copper nanoparticles. Air-stable copper/carbon core/shell nanoparticles (typical size ~23 nm, shell thickness ~1.0 nm) are prepared by means of an electric explosion of wires. Gaseous oxidation of the carbon shells with a defective structure occurs at 180 °C, impacting the choice of organic solvents as well as the sintering conditions to create a crucial neck formation. Isothermal oxidation and reduction treatment at 200 °C for only about 10 min yields an oxide-free copper network structure with an electrical resistivity of 25.1 μΩ cm (14.0 μΩ cm at 250 °C). Finally, conductive copper line patterns are achieved down to a 50 μm width with an excellent printing resolution (standard deviation ~4.0%) onto a polyimide substrate using screen printing of the optimized inks.The realization of air-stable nanoparticles, well-formulated nanoinks, and conductive patterns based on copper is a great challenge in low-cost and large-area flexible printed electronics. This work reports the synthesis of a conductively interconnected copper structure via thermal sintering of copper inks at a low temperature for a short period of time, with the help of thin defective carbon shells coated onto the copper nanoparticles. Air-stable copper/carbon core/shell nanoparticles (typical size ~23 nm, shell thickness ~1.0 nm) are prepared by means of an electric explosion of wires. Gaseous oxidation of the carbon shells with a defective structure occurs at 180 °C, impacting the choice of organic solvents as well as the sintering conditions to create a crucial neck formation

  4. Origin and evolution of paramagnetic states in mixtures of ZnO and carbon nanoparticles during intensive mechanical treatment

    International Nuclear Information System (INIS)

    In this study, the microstructural evolution and reaction processes in the mixture of ZnO + xC nanoparticles during prolonged high-energy mechanical activation were explored. The formation of paramagnetic centers has been identified. It was observed that the evolution of various paramagnetic defects reveals several macroscopic flow processes that take place in the system. Some of these processes are the destruction of primary durable nanoparticle ZnO aggregates, the crushing of individual nanoparticles (250–14 nm), the development of accumulative thermal processes in the sample, the interaction of carbon atoms with oxygen from the treatment chamber and from the surface of the ZnO nanoparticles, the formation of reducing atmosphere in the grinding chamber, and the occurrence of the forming conditions of the phase transition ZnOW → ZnOS on the surface layers of ZnOW nanoparticles

  5. Refinement of the Nanoparticle Emission Assessment Technique into the Nanomaterial Exposure Assessment Technique (NEAT 2.0).

    Science.gov (United States)

    Eastlake, Adrienne C; Beaucham, Catherine; Martinez, Kenneth F; Dahm, Matthew M; Sparks, Christopher; Hodson, Laura L; Geraci, Charles L

    2016-09-01

    Engineered nanomaterial emission and exposure characterization studies have been completed at more than 60 different facilities by the National Institute for Occupational Safety and Health (NIOSH). These experiences have provided NIOSH the opportunity to refine an earlier published technique, the Nanoparticle Emission Assessment Technique (NEAT 1.0), into a more comprehensive technique for assessing worker and workplace exposures to engineered nanomaterials. This change is reflected in the new name Nanomaterial Exposure Assessment Technique (NEAT 2.0) which distinguishes it from NEAT 1.0. NEAT 2.0 places a stronger emphasis on time-integrated, filter-based sampling (i.e., elemental mass analysis and particle morphology) in the worker's breathing zone (full shift and task specific) and area samples to develop job exposure matrices. NEAT 2.0 includes a comprehensive assessment of emissions at processes and job tasks, using direct-reading instruments (i.e., particle counters) in data-logging mode to better understand peak emission periods. Evaluation of worker practices, ventilation efficacy, and other engineering exposure control systems and risk management strategies serve to allow for a comprehensive exposure assessment. PMID:27027845

  6. Refinement of the Nanoparticle Emission Assessment Technique into the Nanomaterial Exposure Assessment Technique (NEAT 2.0)

    Science.gov (United States)

    Eastlake, Adrienne C; Beaucham, Catherine; Martinez, Kenneth F; Dahm, Matthew M; Sparks, Christopher; Hodson, Laura L; Geraci, Charles L

    2016-01-01

    Engineered nanomaterial emission and exposure characterization studies have been completed at more than 60 different facilities by the National Institute for Occupational Safety and Health (NIOSH). These experiences have provided NIOSH the opportunity to refine an earlier published technique, the Nanoparticle Emission Assessment Technique (NEAT 1.0), into a more comprehensive technique for assessing worker and workplace exposures to engineered nanomaterials. This change is reflected in the new name Nanomaterial Exposure Assessment Technique (NEAT 2.0) which distinguishes it from NEAT 1.0. NEAT 2.0 places a stronger emphasis on time-integrated, filter-based sampling (i.e., elemental mass analysis and particle morphology) in the worker's breathing zone (full shift and task specific) and area samples to develop job exposure matrices. NEAT 2.0 includes a comprehensive assessment of emissions at processes and job tasks, using direct-reading instruments (i.e., particle counters) in data-logging mode to better understand peak emission periods. Evaluation of worker practices, ventilation efficacy, and other engineering exposure control systems and risk management strategies serve to allow for a comprehensive exposure assessment. PMID:27027845

  7. Understanding the mechanism of toxicity of carbon nanoparticles in humans in the new millennium: A systemic review

    OpenAIRE

    Sharma Mukesh

    2010-01-01

    Manmade nanoparticles range from the well-established multi-ton production of carbon black and fumed silica for applications in plastic fillers and car tyres to microgram quantities of fluorescent quantum dots used as markers in biological imaging. While benefits of nanotechnology are widely publicized, the discussion of the potential effects of their widespread use in the consumer and industrial products are just beginning to emerge. Acceptance of nanoparticle toxicity led to wide acceptance...

  8. The Role of COX-2 in the Inflammatory and Fibrotic Response in the Lung Following Exposure to Multi-Walled Carbon Nanotubes

    Science.gov (United States)

    Sayers, Brian C.

    Exposure to multiwalled carbon nanotubes (MWCNT) has been demonstrated to exacerbate airway inflammation and fibrosis in allergen-challenged mouse model. These data have led to concern that individuals with asthma could represent a susceptible population to adverse health effects following exposure to MWCNT, and possibly other engineered nanoparticles. Asthma pathogenesis is caused by the interaction of a complex genetic predisposition and environmental exposures. Because chronic airway inflammation is common to all asthma phenotypes, it is logical to investigate genes that are involved in inflammatory pathways in order to understand the genetic basis of asthma. The metabolism of arachidonic acid by cyclooxygenase (COX) enzymes is the rate-determining step in the synthesis of prostanoids, which are biologically active lipids that are important modulators of inflammation. Based on the role of COX enzymes in inflammatory pathways, we sought to investigate how COX enzymes are involved in the inflammatory response following MWCNT exposure in asthmatic airways. We report that MWCNT significantly exacerbated allergen-induced airway inflammation and mucus cell metaplasia in COX-2 deficient mice compared to wild type mice. In addition, MWCNTs significantly enhanced allergen-induced cytokines involved in Th2 (IL-13, IL-5), Th1 (CXCL10), and Th17 (IL-17A) inflammatory responses in COX-2 deficient mice but not in WT mice. We conclude that exacerbation of allergen-induced airway inflammation and mucus cell metaplasia by MWCNTs is enhanced by deficiency in COX-2 and associated with activation of a mixed Th1/Th2/Th17 immune response. Based on our observation that COX-2 deficient mice developed a mixed Th immune response following MWCNT exposure, we sought to evaluate how cytokines associated with different Th immune responses alter COX expression following MWCNT exposure. For this study, a mouse macrophage cell line (RAW264.7) was used because MWCNT were largely sequestered

  9. Facile and Green Synthesis of Palladium Nanoparticles-Graphene-Carbon Nanotube Material with High Catalytic Activity

    OpenAIRE

    Tai Sun; Zheye Zhang; Junwu Xiao; Chen Chen; Fei Xiao; Shuai Wang; Yunqi Liu

    2013-01-01

    We report a facile and green method to synthesize a new type of catalyst by coating Pd nanoparticles (NPs) on reduced graphene oxide (rGO)-carbon nanotube (CNT) nanocomposite. An rGO–CNT nanocomposite with three-dimensional microstructures was obtained by hydrothermal treatment of an aqueous dispersion of graphene oxide (GO) and CNTs. After the rGO–CNT composites have been dipped in K2PdCl4 solution, the spontaneous redox reaction between the GO–CNT and PdCl4 2− led to the formation of nanohy...

  10. Strings of interconnected hollow carbon nanoparticles with porous shells prepared using simple solid-phase synthesis

    International Nuclear Information System (INIS)

    Strings of interconnected hollow carbon nanoparticles with porous shells were prepared by simple heat-treatments of a mixture of resorcinol-formaldehyde gel and transition-metal salts. The sample was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and nitrogen adsorption. Results show that the sample consisted of relatively uniform hollow particles with sizes ranging from 70 to 80 nm forming a strings-of-pearls-like nanostructure. The material with porous shells possessed well-developed graphitic structure with an interlayer (d002) spacing of 0.3369 nm and the stack height of the graphite crystallites of 9 nm

  11. Tribological Properties of WS2 Nanoparticles Lubricants on Aluminum-Silicon Alloy and Carbon Steels

    OpenAIRE

    Riyadh A. AL-SAMARAI; Yarub AL-DOURI; Haftirman HAFTIRMAN; Khiarel Rafzi AHMAD

    2013-01-01

    The rheological properties of nanometric tungsten disulphide (WS2) nanoparticles oil lubricants and its tribological performance with two hypereutectic Al-Si alloy and carbon steel are examined. These two oils are used to reduce wear and friction and to explore the actions via tribological pin-on-disk tests. The pin was made from hypereutectic Al-Si alloy on steel disk, taking into consideration the effect of loads (10, 20, 30 N) and different speed (200, 300, 400 rpm). Oils with and without ...

  12. Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure

    International Nuclear Information System (INIS)

    To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol−1, during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons. -- Highlights: • Upper canopy leaf of Siebold's beech is sensitive to ozone. • The net carbon gain of canopy was reduced by ozone. • Enhanced respiration by ozone highly contributes to net carbon gain in late summer. -- Contributions of ozone-induced reduction in photosynthesis and increase in respiration to canopy net carbon gain of beech sapling were different between seasons

  13. Analysis of the cytotoxicity of carbon-based nanoparticles, diamond and graphite, in human glioblastoma and hepatoma cell lines

    DEFF Research Database (Denmark)

    Zakrzewska, Karolina Ewa; Samluk, Anna; Wierzbicki, Mateusz; Jaworski, Sławomir; Kutwin, Marta; Sawosz, Ewa; Chwalibog, André; Pijanowska, Dorota Genowefa; Pluta, Krzysztof Dariusz

    2015-01-01

    carbon nanoparticles could be a potentially useful tool for therapeutics delivery to the brain tissue with minimal side effects on the hepatocytes. Furthermore, we showed the influence of the nanoparticles on the stable, fluorescently labeled tumor cell lines and concluded that the labeled cells are......Nanoparticles have attracted a great deal of attention as carriers for drug delivery to cancer cells. However, reports on their potential cytotoxicity raise questions of their safety and this matter needs attentive consideration. In this paper, for the first time, the cytotoxic effects of two...

  14. Influence of nanoparticle size to the electrical properties of naphthalenediimide on single-walled carbon nanotube wiring

    Science.gov (United States)

    Tanaka, Hirofumi; Hong, Liu; Fukumori, Minoru; Negishi, Ryota; Kobayashi, Yoshihiro; Tanaka, Daisuke; Ogawa, Takuji

    2012-06-01

    Nanoparticles of N,N‧-bis(n-alkyl)tetracarbonatenaphthalenediimide (NDI) were adsorbed on single-walled carbon nanotube (SWNT) wires dispersed on a SiO2 substrate. The electrical properties were measured along the long axis of the SWNTs, and in all cases through the nanoparticles showed rectification in semiconducting I-V curve. The plateau width of the I-V curve through the NDI nanoparticles on metallic SWNTs decreased as the particle size increased, while the rectification ratio increased. The conduction mechanism was changed from tunneling conduction to Schottky-like conduction and their boundary is at about 3 nm diameter.

  15. Fabrication of carbon microcapsules containing silicon nanoparticles-carbon nanotubes nanocomposite by sol-gel method for anode in lithium ion battery

    International Nuclear Information System (INIS)

    Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT-C) have been fabricated by a surfactant mediated sol-gel method followed by a carbonization process. Silicon nanoparticles-carbon nanotubes (Si-CNT) nanohybrids were produced by a wet-type beadsmill method. To obtain Si-CNT nanocomposites with spherical morphologies, a silica precursor (tetraethylorthosilicate, TEOS) and polymer (PMMA) mixture was employed as a structure-directing medium. Thus the Si-CNT/Silica-Polymer microspheres were prepared by an acid catalyzed sol-gel method. Then a carbon precursor such as polypyrrole (PPy) was incorporated onto the surfaces of pre-existing Si-CNT/silica-polymer to generate Si-CNT/Silica-Polymer-PPy microspheres. Subsequent thermal treatment of the precursor followed by wet etching of silica produced Si-CNT-C microcapsules. The intermediate silica/polymer must disappear during the carbonization and etching process resulting in the formation of an internal free space. The carbon precursor polymer should transform to carbon shell to encapsulate remaining Si-CNT nanocomposites. Therefore, hollow carbon microcapsules containing Si-CNT nanocomposites could be obtained (Si-CNT-C). The successful fabrication was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). These final materials were employed for anode performance improvement in lithium ion battery. The cyclic performances of these Si-CNT-C microcapsules were measured with a lithium battery half cell tests. - Graphical Abstract: Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT-C) have been fabricated by a surfactant mediated sol-gel method. Highlights: → Polymeric microcapsules containing Si-CNT transformed to carbon microcapsules. → Accommodate volume changes of Si NPs during Li ion charge/discharge. → Sizes of microcapsules were controlled by experimental parameters.

  16. Electrochemical Glucose Oxidation Using Glassy Carbon Electrodes Modified with Au-Ag Nanoparticles: Influence of Ag Content

    Directory of Open Access Journals (Sweden)

    Nancy Gabriela García-Morales

    2015-01-01

    Full Text Available This paper describes the application of glassy carbon modified electrodes bearing Aux-Agy nanoparticles to catalyze the electrochemical oxidation of glucose. In particular, the paper shows the influence of the Ag content on this oxidation process. A simple method was applied to prepare the nanoparticles, which were characterized by transmission electron microscopy, Ultraviolet-Visible spectroscopy, X-ray diffraction spectroscopy, and cyclic voltammetry. These nanoparticles were used to modify glassy carbon electrodes. The effectiveness of these electrodes for electrochemical glucose oxidation was evaluated. The modified glassy carbon electrodes are highly sensitive to glucose oxidation in alkaline media, which could be attributed to the presence of Aux-Agy nanoparticles on the electrode surface. The voltammetric results suggest that the glucose oxidation speed is controlled by the glucose diffusion to the electrode surface. These results also show that the catalytic activity of the electrodes depends on the Ag content of the nanoparticles. Best results were obtained for the Au80-Ag20 nanoparticles modified electrode. This electrode could be used for Gluconic acid (GA production.

  17. Investigation of the effects of short-term inhalation of carbon nanoparticles on brains and lungs of c57bl/6j and p47(phox-/-) mice.

    Science.gov (United States)

    van Berlo, D; Hullmann, M; Wessels, A; Scherbart, A M; Cassee, F R; Gerlofs-Nijland, M E; Albrecht, C; Schins, R P F

    2014-07-01

    Recent studies indicate that the brain is a target for toxic carbonaceous nanoparticles present in ambient air. It has been proposed that the neurotoxic effects of such particles are driven by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase mediated generation of reactive oxygen species (ROS) in activated microglia. In the present study, we have evaluated the effects of short term (4h) nose-only inhalation exposure to carbon NP (CNP) in the brains and lungs of C57BL/6J mice and in p47(phox-/-) mice that lack a functional NADPH oxidase. It was shown that the lungs of the p47(phox-/-) mice are less responsive to CNP inhalation than lungs of the corresponding C57BL/6J control animals. Lung tissue mRNA expression of the oxidative stress/DNA damage response genes 8-oxoguanine glycosylase (OGG1) and apurinic/apyrimidinic endonuclease 1 (APE1) were induced by CNP exposure in C57BL/6J but not in the p47(phox-/-) mice. In contrast, the expression of these genes, as well as Tumor Necrosis Factor-α (TNFα), Cyclooxygenase-2 (COX-2) and Heme Oxygenase-1 (HO-1) was not altered in the olfactory bulb, cerebellum or remaining brain tissue part of either mouse background. This indicates that neuroinflammation was not induced by this exposure. CNP inhalation for 4h or for 4h on three consecutive days also did not affect brain tissue protein expression of interleukin (IL)-1β, while a clear significant difference in constitutive expression level of this pro-inflammatory cytokine was found between C57BL/6J and p47(phox-/-) mice. In conclusion, short-term inhalation exposure to pure carbon nanoparticles can trigger mild p47(phox) dependent oxidative stress responses in the lungs of mice whereas in their brains at the same exposure levels signs of oxidative stress and inflammation remain absent. The possible role of p47(phox) in the neuro-inflammatory effects of nanoparticles in vivo remains to be clarified. PMID:24792328

  18. Manipulation of combustion waves in carbon-nanotube/fuel composites by highly reactive Mg nanoparticles

    Science.gov (United States)

    Lee, Kang Yeol; Hwang, Hayoung; Shin, Dongjoon; Choi, Wonjoon

    2015-10-01

    Manipulating the interface of micro/nanostructured materials and chemical fuels can change the fundamental characteristics of combustion waves that are generated during a reaction. In this study, we report that Mg/MgO nanoparticles actively amplify the propagation of combustion waves at the interface of multi-walled carbon nanotubes (MWCNTs) and chemical fuels. Fuel/MWCNT and fuel/MWCNT-Mg/MgO composite films were prepared by a facile synthetic method. We present complete physiochemical characterization of these composite films and evaluate the propagating velocities and real-time surface temperatures of combustion waves. Mg/MgO nanoparticles at the interface enhanced the reaction front velocity by 41%. The resulting explosive reactions supplied additional thermal energy to the chemical fuel, accelerating flame propagation. Furthermore, the surface temperatures of the composites with Mg/MgO nanoparticles were much lower, indicating how the transient heat from the reaction would ignite the unreacted fuels at lower surface temperatures despite not reaching the necessary activation energy for a chain reaction. This mechanism contributed to thermopower waves that amplified the output voltage. Furthermore, large temperature gradients due to the presence of nanoparticles increased charge transport inside the nanostructured material, due to the increased thermoelectric effects. This manipulation could contribute to the active control of interfacially driven combustion waves along nanostructured materials, yielding many potential applications.Manipulating the interface of micro/nanostructured materials and chemical fuels can change the fundamental characteristics of combustion waves that are generated during a reaction. In this study, we report that Mg/MgO nanoparticles actively amplify the propagation of combustion waves at the interface of multi-walled carbon nanotubes (MWCNTs) and chemical fuels. Fuel/MWCNT and fuel/MWCNT-Mg/MgO composite films were prepared by a facile

  19. Peapod-like composite with nickel phosphide nanoparticles encapsulated in carbon fibers as enhanced anode for li-ion batteries.

    Science.gov (United States)

    Zhang, Huijuan; Feng, Yangyang; Zhang, Yan; Fang, Ling; Li, Wenxiang; Liu, Qing; Wu, Kai; Wang, Yu

    2014-07-01

    Herein, we introduce a peapod-like composite with Ni12 P5 nanoparticles encapsulated in carbon fibers as the enhanced anode in Li-ion batteries for the first time. In the synthesis, NiNH4 PO4 ⋅H2 O nanorods act as precursors and sacrificial templates, and glucose molecules serve as the green carbon source. With the aid of hydrogen bonding between the precursor and carbon source, a polymer layer is hydrothermally formed and then rationally converted into carbon fibers upon inert calcination at elevated temperatures. Meanwhile, NiNH4 PO4 ⋅H2 O nanorods simultaneously turn into Ni12 P5 nanoparticles encapsulated in carbon fibers by undergoing a decomposition and reduction process induced by high temperature and the carbon fibers. The obtained composite performs excellently as a Li-ion batteries anode relative to pure-phase materials. Specific capacity can reach 600 m Ah g(-1) over 200 cycles, which is much higher than that of isolated graphitized carbon or phosphides, and reasonably believed to originate from the synergistic effect based on the combination of Ni12 P5 nanoparticles and carbon fibers. Due to the benignity, sustainability, low cost, and abundance of raw materials of the peapod-like composite, numerous potential applications, in fields such as optoelectronics, electronics, specific catalysis, gas sensing, and biotechnology can be envisaged. PMID:24648293

  20. Hydrogen peroxide sensor based on modified vitreous carbon with multiwall carbon nanotubes and composites of Pt nanoparticles-dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, C.; Orozco, G. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S.C., P.O. Box 064, C.P. 76700, Pedro Escobedo, Queretaro (Mexico); Verde, Y. [Instituto Tecnologico de Cancun, Av. Kabah Km. 3, C.P. 77500, Cancun, Quintana Roo (Mexico); Jimenez, S. [Unidad Queretaro Centro de Investigacion y de Estudios Avanzados del I.P.N., Juriquilla, Santiago de Queretaro (Mexico); Godinez, Luis A. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S.C., P.O. Box 064, C.P. 76700, Pedro Escobedo, Queretaro (Mexico); Juaristi, E. [Chemistry Department, Centro de Investigacion y de Estudios Avanzados del I.P.N., P.O. Box 14-740, C.P. 07360 Mexico, D.F. (Mexico); Bustos, E. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S.C., P.O. Box 064, C.P. 76700, Pedro Escobedo, Queretaro (Mexico); Chemistry Department, Centro de Investigacion y de Estudios Avanzados del I.P.N., P.O. Box 14-740, C.P. 07360 Mexico, D.F. (Mexico)], E-mail: ebustos@cideteq.mx

    2009-02-15

    Sensors using nanostructured materials have been under development in the last decade due to their selectivity for the detection and quantification of different compounds. The physical and chemical characteristics of carbon nanotubes provide significant advantages when used as electrodes for electronic devices, fuel cells and electrochemical sensors. This paper presents preliminary results on the modification of vitreous carbon electrodes with Multiwall Carbon Nanotubes (MWCNTs) and composites of Pt nanoparticles-dopamine (DA) as electro-catalytic materials for the hydrogen peroxide (H{sub 2}O{sub 2}) reaction. Chemical pre-treatment and consequent functionalization of MWCNTs with carboxylic groups was necessary to increase the distribution of the composites. In addition, the presence of DA was important to protect the active sites and eliminate the pasivation of the surface after the electro-oxidation of H{sub 2}O{sub 2} takes place. The proposed H{sub 2}O{sub 2} sensor exhibited a linear response in the 0-5 mM range, with detection and quantification limits of 0.3441 mM and 1.1472 mM, respectively.

  1. Porous carbon protected magnetite and silver hybrid nanoparticles: morphological control, recyclable catalysts, and multicolor cell imaging.

    Science.gov (United States)

    Wang, Hui; Shen, Jing; Li, Yingyu; Wei, Zengyan; Cao, Guixin; Gai, Zheng; Hong, Kunlun; Banerjee, Probal; Zhou, Shuiqin

    2013-10-01

    A simple and facile synthetic strategy is developed to prepare a new class of multifunctional hybrid nanoparticles (NPs) that can integrate a magnetic core with silver nanocrystals embedded in porous carbon shell. The method involves a one-step solvothermal synthesis of Fe3O4@C template NPs with Fe3O4nanocrystals in the core protected by a porous carbon shell, followed by loading and in situ reduction of silver ions in the carbon shell in water at room temperature. The core-satellite and dumbbell-like nanostructures of the resulted Fe3O4@C-Ag hybrid NPs can be readily controlled by loading amount of silver ions. The hybrid NPs can efficiently catalyze the reduction reaction of organic dyes in water. The easy magnetic separation and high stability of the catalytically active silver nanocrystals embedded in the carbon shell enable the hybrid NPs to be recycled for reuse as catalysts. The hybrid NPs can also overcome cellular barriers to enter the intracellular region and light up the mouse melanoma B16F10 cells in multicolor modal, with no cytotoxicity. Such porous carbon protected Fe3O4@C-Ag hybrid NPs with controllable nanostructures and a combination of magnetic and noble metallic components have great potential for a broad range of applications in the catalytic industry and biomedical field. PMID:24001139

  2. Morphological Lesions in Mouse Liver and Lungs After Lung Exposure to Carbon Nanotubes

    DEFF Research Database (Denmark)

    Szarek, J.; Mortensen, Alicja; Jackson, P.; Saber, A.T.; Kyjovska, Z.O.; Wallin, H.; Vogel, U.; Hougaard, K.S.

    2013-01-01

    . Materials and Methods: One day before mating, 30 mice (C57BL/6BomTac, Taconic Europe, Denmark) were given 67 μg multi-walled carbon nanotubes (NM-400, Nanocyl, Belgium) intratracheally (group A). A further 30 control mice (group B) received vehicle (Millipore water with 2% mouse serum). Lungs and liver were...... macrophages. Oedema was slight in A2 mice, but infiltration of macrophages was more intense. In the liver, microfoci of necrosis, infiltration of inflammatory cells and lesions of Kupffer cells were more intense in A1 than A2 mice. Conclusions: Intratracheal exposure to multi-walled carbon nanotubes caused...... taken from six animals from each group for histopathological examination (haematoxylin and eosin staining) 6 weeks (A1, B1 group) and 4 months (A2, B2) after exposure. Results: Lungs in A1 mice showed bronchiolar subepithelial oedema and perivascular oedema and sporadic hyperaemia and the presence of...

  3. Interaction of soot derived multi-carbon nanoparticles with lung surfactants and their possible internalization inside alveolar cavity.

    Science.gov (United States)

    Kumar, Pradip; Bohidar, H B

    2010-10-01

    A systematic investigation of interaction of multi-carbon nanoparticles, obtained from soot, with dipalmitoyl phosphatidylcholine (DPPC), a clinical pulmonary phospholipid surfactant, sold under trade name "Survanta", was undertaken to establish a model for internalization of these nanoparticles inside alveolar cavity. In vitro experiments were carried out to establish the phospholipid assisted dispersion mechanism of carbon nanoclusters (size approximately 150 nm, zeta potential approximately -15 mV) in water. Results obtained from an array of experimental methods, like dynamic laser light scattering, electrophoresis, UV-absorption spectroscopy, surface tension studies and transmission electron microscopy, revealed that the carbon nanoparticles interacted with DPPC predominantly via hydrophobic interactions. Selective surface adsorption of DPPC molecules on nanoparticle surface was found to be strongly dependent on the concentration of the phospholipid. DPPC, a gemini surfactant, formed a rigid monolayer around the carbon nanocluster even at nanomolar concentration and provided excellent stability to the dispersion. Based on the experimental data it is proposed that the free-energy gain involved in the hydrophobic interactions will facilitate the internalization of these nanoparticles on the inner wall of the alveolar cavity. PMID:21299046

  4. Using city-wide mobile noise assessments to estimate bicycle trip annual exposure to Black Carbon.

    Science.gov (United States)

    Dekoninck, Luc; Botteldooren, Dick; Int Panis, Luc

    2015-10-01

    Several studies have shown that a significant amount of daily air pollution exposure, in particular Black Carbon (BC), is inhaled during bicycle trips. Previously, the instantaneous BC exposure of cyclists was modeled as the sum of a background concentration and a local traffic related component based on a local assessment of traffic noise. We present a fast and low cost methodology to achieve a city-wide assessment of yearly average BC exposure of cyclists along their trips, based on a city-wide mobile noise sensing campaign. The methodology requires participatory sensing measurements of noise, partially combined with BC and/or other air pollutants sensitive to local traffic variations. The combined measurements cover the spatial and meteorological variability and provide the data for an instantaneous exposure model. The mobile noise-only measurements map the full city; and yearly meteorology statistics are used to extrapolate the instantaneous exposure model to a yearly average map of in-traffic air pollution exposure. Less than four passages at each segment along the network with mobile noise equipment are necessary to reach a standard error of 500 ng/m(3) for the yearly average BC exposure. A strong seasonal effect due to the BC background concentration is detected. The background contributes only 25% to the total trip exposure during spring and summer. During winter the background component increases to 50-60%. Engine related traffic noise along the bicyclist's route is a valid indicator of the BC exposure along the route, independent of the seasonal background. Low exposure route selection results in an exposure reduction of 35% in winter and 60% in summer, sensitive to the weather conditions, specific trip attributes and the available alternatives. The methodology is relevant for further research into the local effects of air pollution on health. Mobile noise mapping adds local traffic data including traffic dynamics into the air pollution exposure

  5. Trend of exposure to carbon monoxide in Tehran taxi drivers during one year

    OpenAIRE

    Mohammad Javad Golhosseini; Hossein Kakooei; Jamaleddin Shahtaheri; Kamal Azam

    2015-01-01

    Background and Aim: Motor vehicles are an absolute necessity used extensively in all countries of the world. They are a major cause of air pollution with highly undesirable consequences. Thus, exposure to traffic pollution is a growing public health concern. Several studies indicate that people in the cabin of a vehicle inhale air with high concentrations of pollutants such as nitrogen oxides(NOx), particulate matter (PM), volatile compounds (VOCs) and carbon monoxide (CO).   Materials and Me...

  6. EXPOSURE TO CARBONIC GAS ENRICHED ATMOSPHERE OR ELECTRICAL WATER BATH TO STUN OR KILL CHICKENS

    OpenAIRE

    JP Nicolau; MF Pinto; EHG Ponsano; SHV Perri; M Garcia Neto

    2015-01-01

    ABSTRACTThe objective of this study was to compare the effects of two methods (electrical water bath or carbonic gas atmosphere) for stunning or killing broiler chickens prior to bleeding on weight loss due to bleeding and meat traits. A completely randomized design with 2 x 2 factorial arrangement (electrical or gas system x stunning or killing) was applied. The time required for stunning and killing and the birds' behavior were evaluated for the gas exposure method. The birds killed by the ...

  7. Neurodevelopmental consequences of sub-clinical carbon monoxide exposure in newborn mice.

    Directory of Open Access Journals (Sweden)

    Ying Cheng

    Full Text Available Carbon monoxide (CO exposure at high concentrations results in overt neurotoxicity. Exposure to low CO concentrations occurs commonly yet is usually sub-clinical. Infants are uniquely vulnerable to a variety of toxins, however, the effects of postnatal sub-clinical CO exposure on the developing brain are unknown. Apoptosis occurs normally within the brain during development and is critical for synaptogenesis. Here we demonstrate that brief, postnatal sub-clinical CO exposure inhibits developmental neuroapoptosis resulting in impaired learning, memory, and social behavior. Three hour exposure to 5 ppm or 100 ppm CO impaired cytochrome c release, caspase-3 activation, and apoptosis in neocortex and hippocampus of 10 day old CD-1 mice. CO increased NeuN protein, neuronal numbers, and resulted in megalencephaly. CO-exposed mice demonstrated impaired memory and learning and reduced socialization following exposure. Thus, CO-mediated inhibition of neuroapoptosis might represent an important etiology of acquired neurocognitive impairment and behavioral disorders in children.

  8. High cyclability of carbon-coated TiO2 nanoparticles as anode for sodium-ion batteries

    International Nuclear Information System (INIS)

    Highlights: • Titanium oxide nanopaticles were modified by carbon coating from pyrolyzing of PVP. • Carbon coating gave rise to excellent cycling ability of TiO2 for sodium-ion batteries. • The reversible capacity of carbon-coated TiO2 reached 242.3 mAh g−1 at 30 mA g−1. • Good rate performance of carbon-coated TiO2 was presented up to 800 mA g−1. - Abstract: Owing to the merits of good chemical stability, elemental abundance and nontoxicity, titanium dioxide (TiO2) has drawn increasing attraction for use as anode material in sodium-ion batteries. Nanostructured TiO2 was able to achieve high energy density. However, nanosized TiO2 is typically electrochemical instable, which leads to poor cycling performance. In order to improve the cycling stability, carbon from thermolysis of poly(vinyl pyrrolidone) was coated onto TiO2 nanoparticles. Electronic conductivity and electrochemical stability were enhanced by coating carbon onto TiO2 nanoparticles. The resultant carbon-coated TiO2 nanoparticles exhibited high reversible capacity (242.3 mAh g−1), high coulombic efficiency (97.8%), and good capacity retention (87.0%) at 30 mA g−1 over 100 cycles. By comparison, untreated TiO2 nanoparticles showed comparable reversible capacity (237.3 mAh g−1) and coulombic efficiency (96.2%), but poor capacity retention (53.2%) under the same condition. The rate performance of carbon-coated TiO2 nanoparticles was also displayed as high as 127.6 mAh g−1 at a current density of 800 mA g−1. The improved cycling performance and rate capability were mostly attributed to protective carbon layer helping stablize solid electrolyte interface formation of TiO2 nanoparticles and improving the electronic conductivity. Therefore, it is demonstrated that carbon-coated TiO2 nanoparticles are promising anode candidate for sodium-ion batteries

  9. Morphokinetics of mesenterial lymphatic node cell populations at exposure of gold nanoparticles in experiment

    Directory of Open Access Journals (Sweden)

    O.V. Zlobina

    2012-12-01

    Full Text Available The influence of gold nanoparticles with different size (1-3 nm, 15 nm and 50 nm on the morphokinetics of mesenterial lymphatic node cell populations of healthy laboratory animals was investigated. It was established that the oral administration of gold nanoparticles caused the changes of morphokinetics of mesenterial lymphatic node cell populations. The morphological reorganizations in the mesenterial lymphatic nodes testified about activation of migration processes, the proliferation and differentiation processes of immunocompetent cells, which assumes the presence of immunomodulating action of gold nanoparticles.

  10. Toxicological risk assessment of elemental gold following oral exposure to sheets and nanoparticles – A review

    DEFF Research Database (Denmark)

    Hadrup, Niels; Sharma, Anoop Kumar; Poulsen, Morten;

    2015-01-01

    Elemental gold is used as a food coloring agent and in dental fillings. In addition, gold nanoparticles are gaining increasing attention due to their potential use as inert carriers for medical purposes. Although elemental gold is considered to be inert, there is evidence to suggest the release of....... In addition, gold released from dental restorations has been reported to increase the risk of developing gold hypersensitivity. Regarding genotoxicity, in vitro studies indicate that gold nanoparticles induce DNA damage in mammalian cells. In vivo, gold nanoparticles induce genotoxic effects in...

  11. Agglomeration of tungsten carbide nanoparticles in exposure medium does not prevent uptake and toxicity toward a rainbow trout gill cell line.

    Science.gov (United States)

    Kühnel, Dana; Busch, Wibke; Meissner, Tobias; Springer, Armin; Potthoff, Annegret; Richter, Volkmar; Gelinsky, Michael; Scholz, Stefan; Schirmer, Kristin

    2009-06-28

    Due to their increased production and use, engineered nanoparticles are expected to be released into the aquatic environment where particles may agglomerate. The aim of this study was to explore the role of agglomeration of nanoparticles in the uptake and expression of toxicity in the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1. This cell line was chosen as model because it is known to be amenable to culture in complete as well as greatly simplified exposure media. Nano-sized tungsten carbide (WC) with or without cobalt doping (WC-Co), two materials relevant in the heavy metal industry, were applied as model particles. These particles were suspended in culture media with decreasing complexity from L15 with 10% fetal bovine serum (FBS) to L15 to L15/ex, containing only salts, galactose and pyruvate of the complete medium L15. Whereas the serum supplement in L15 retained primary nanoparticle suspensions, agglomerates were formed quickly in L15 and L15/ex. Nevertheless, scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) elemental analysis revealed an uptake of both WC and WC-Co nanoparticles into RTgill-W1 cells irrespective of the state of agglomeration of nanoparticles. The localisation seemed to be restricted to the cytoplasm, as no particles were observed in the nucleus of cells. Moreover, reduction in cell viability between 10 and 50% compared to controls were observed upon particle exposure in all media although the pattern of impact varied depending on the medium and exposure time. Short-term exposure of cells led to significant cytotoxicity at the highest nominal particle concentrations, irrespective of the particle type or exposure medium. In contrast, long-term exposures led to preferential toxicity in the simplest medium, L15/ex, and an enhanced toxicity by the cobalt-containing WC nanoparticles in all exposure media. The composition of the exposure media also influenced the toxicity of the cobalt ions, which may

  12. Agglomeration of tungsten carbide nanoparticles in exposure medium does not prevent uptake and toxicity toward a rainbow trout gill cell line

    International Nuclear Information System (INIS)

    Due to their increased production and use, engineered nanoparticles are expected to be released into the aquatic environment where particles may agglomerate. The aim of this study was to explore the role of agglomeration of nanoparticles in the uptake and expression of toxicity in the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1. This cell line was chosen as model because it is known to be amenable to culture in complete as well as greatly simplified exposure media. Nano-sized tungsten carbide (WC) with or without cobalt doping (WC-Co), two materials relevant in the heavy metal industry, were applied as model particles. These particles were suspended in culture media with decreasing complexity from L15 with 10% fetal bovine serum (FBS) to L15 to L15/ex, containing only salts, galactose and pyruvate of the complete medium L15. Whereas the serum supplement in L15 retained primary nanoparticle suspensions, agglomerates were formed quickly in L15 and L15/ex. Nevertheless, scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) elemental analysis revealed an uptake of both WC and WC-Co nanoparticles into RTgill-W1 cells irrespective of the state of agglomeration of nanoparticles. The localisation seemed to be restricted to the cytoplasm, as no particles were observed in the nucleus of cells. Moreover, reduction in cell viability between 10 and 50% compared to controls were observed upon particle exposure in all media although the pattern of impact varied depending on the medium and exposure time. Short-term exposure of cells led to significant cytotoxicity at the highest nominal particle concentrations, irrespective of the particle type or exposure medium. In contrast, long-term exposures led to preferential toxicity in the simplest medium, L15/ex, and an enhanced toxicity by the cobalt-containing WC nanoparticles in all exposure media. The composition of the exposure media also influenced the toxicity of the cobalt ions, which may

  13. Preparation of carbon nanotubes decorated with manganese dioxide nanoparticles for electrochemical determination of ferulic acid

    International Nuclear Information System (INIS)

    We report on an electrochemical sensor for the detection of ferulic acid (FA) that is based on a glassy carbon electrode modified with functional multiwalled carbon nanotubes that are decorated with MnO2 nanoparticles. The new electrode shows excellent electrochemical catalytic activity towards the oxidation of ferulic acid at pH 7. Cyclic voltammetry reveals a 23 mV decrease in the peak-to-peak separation of the oxidation and reduction waves. Under optimized conditions, the anodic peak current at a voltage of 150 mV (vs. Ag/AgCl) is linearly related to the peak current in the 0.082–220 μM concentration range, and the limit of detection (at an SNR of 3) is 10 nM. The sensor was applied to the determination of FA in spiked human serum samples and gave satisfactory results, with recoveries ranging from 97 to 99.2 %. (author)

  14. Interaction between Palladium Nanoparticles and Surface-Modified Carbon Nanotubes: Role of Surface Functionalities

    DEFF Research Database (Denmark)

    Zhang, Bingsen; Shao, Lidong; Zhang, Wei;

    2014-01-01

    feature, instability, and subtle response of the components upon application of an external field. Herein, we use insitu TEM, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy techniques to record the interaction in palladium on carbon nanotubes (CNTs) from room temperature to 600...... degrees C. We focus on probing the effects of oxygen and nitrogen-containing functional groups on supported palladium nanoparticles (NPs) in the model catalytic system. The stability of palladium NPs supported on CNTs depends strongly on the surface properties of CNTs. Moreover, the oxygen......-containing functional groups on the CNT surfaces, such as carboxylic acids and anhydrides, have an even stronger interaction with palladium NPs than the nitrogen-containing counterparts. Our work contributes to elucidation of the complex metal-carbon interaction and unlocks potential in activity and selectivity control...

  15. Percolation of Carbon Nanoparticles in Poly(3-Hexylthiophene Enhancing Carrier Mobility in Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Chang-Hung Lee

    2014-01-01

    Full Text Available To improve the field-effect mobility of all-inkjet-printed organic thin film transistors (OTFTs, a composite material consisted of carbon nanoparticles (CNPs and poly(3-hexylthiophene (P3HT was reported by using homemade inkjet-printing system. These all-inkjet-printed composite OTFTs represented superior characteristics compared to the all-inkjet-printed pristine P3HT OTFTs. To investigate the enhancement mechanism of the blended materials, the percolation model was established and experimentally verified to illustrate the enhancement of the electrical properties with different blending concentrations. In addition, experimental results of OTFT contact resistances showed that both contact resistance and channel resistance were halved. At the same time, X-ray diffraction measurements, Fourier transform infrared spectra, ultraviolet-visible light, and photoluminescence spectra were also accomplished to clarify the material blending effects. Therefore, this study demonstrates the potential and guideline of carbon-based nanocomposite materials in all-inkjet-printed organic electronics.

  16. Hyperbranched polymer mediated fabrication of water soluble carbon nanotube-metal nanoparticle hybrids

    Science.gov (United States)

    Li, Haiqing; Cooper-White, Justin J.

    2013-03-01

    1-Pyrenemethanol initiated hyperbranched polyglycerol (PiHP) has been synthesized and utilized to non-covalently functionalize pristine multi-walled carbon nanotubes (CNTs) through π-π stacking interactions. Mediated with the PiHP coating, a variety of metal nanoparticles (Au, Ag, Pd and Pt) were in situ generated and randomly tethered on the CNT sidewalls, producing various water-soluble CNT/PiHP/metal hybrids. Particularly, the resulting CNT/PiHP/Pt hybrids possess improved metal coverage in comparison to the reported CNT/Pt nanohybrids obtained by the use of conventional non-covalent CNT surface-modifiers. Depending on the using concentration of Pt2+ precursor, Pt coverage in CNT/PiHP/Pt hybrids can be effectively controlled. In the meanwhile, Pt component on the CNT sidewalls can be either well isolated nanoparticles or loose ``nanoclusters''. To test the promising catalytic application of these obtained CNT/PiHP/Pt hybrids, a systematic investigation on their catalytic performance towards the reduction of 4-nitrophenol to produce 4-aminophenol was performed. Surprisingly, these hybrids exhibited significantly enhanced catalytic activity compared with the conventionally utilized Au and Ag nanoparticles. Moreover, they can be easily recovered and reused without significant loss in catalytic activity after running 6 circles.

  17. Electrospinning, characterization and in vitro biological evaluation of nanocomposite fibers containing carbonated hydroxyapatite nanoparticles

    International Nuclear Information System (INIS)

    Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) fibers containing carbonated hydroxyapatite (CHA) nanoparticles with different CHA amounts (5, 10 and 15 wt%) were electrospun with the aid of ultrasonic power for dispersing the nanoparticles. Scanning electron microscopy and energy-dispersive x-ray spectroscopy results showed that the distribution of CHA within the CHA/PHBV nanocomposite fibers was homogeneous when the CHA content was 10 wt%. Slight particle agglomeration occurred when the CHA content was 15 wt%. The diameters of the electrospun CHA/PHBV nanocomposite fibers and PHBV polymer fibers were around 3 μm. Fourier transform infrared spectroscopic analysis further confirmed the presence of CHA in CHA/PHBV nanocomposite fibers. Both PHBV and CHA/PHBV fibrous membranes exhibited similar tensile properties. Compared with PHBV solvent-cast film, the PHBV fibrous membrane was hydrophobic but the incorporation of CHA nanoparticles dramatically enhanced its wettability. In vitro studies revealed that both types of electrospun fibrous membranes (PHBV and CHA/PHBV) supported the proliferation of human osteoblastic cells (SaOS-2). The alkaline phosphatase activity of SaOS-2 cells seeded on the CHA/PHBV fibrous membranes was higher than that of the cells seeded on the PHBV fibrous membranes after 14 days of cell culture. The electrospun CHA/PHBV nanocomposite fibrous membranes show promises for bone tissue engineering applications.

  18. Recent Updates of DNA Incorporated in Carbon Nanotubes and Nanoparticles for Electrochemical Sensors and Biosensors

    Directory of Open Access Journals (Sweden)

    Umasankar Yogeswaran

    2008-11-01

    Full Text Available Innovations in the field of electrochemical sensors and biosensors are of much importance nowadays. These devices are designed with probes and micro electrodes. The miniaturized designs of these sensors allow analyses of materials without damaging the samples. Some of these sensors are also useful for real time analysis within the host system, so these sensors are considered to be more advantageous than other types of sensors. The active sensing materials used in these types of sensors can be any material that acts as a catalyst for the oxidation or reduction of particular analyte or set of analytes. Among various kinds of sensing materials, deoxyribonucleic acid (DNA, carbon nanotubes (CNTs and nanoparticles have received considerable attraction in recent years. DNA is one of the classes of natural polymers, which can interact with CNTs and nanoparticles to form new types of composite materials. These composite materials have also been used as sensing materials for sensor applications. They have advantages in characteristics such as extraordinary low weight and multifunctional properties. In this article, advantages of DNA incorporated in CNT and nanoparticle hybrids for electrochemical sensors and biosensors are presented in detail, along with some key results noted from the literature.

  19. Electrospinning, characterization and in vitro biological evaluation of nanocomposite fibers containing carbonated hydroxyapatite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Tong Howang; Wang Min [Department of Mechanical Engineering, Faculty of Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Li Zhaoyang; Lu, William W, E-mail: memwang@hku.h [Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Sassoon Road (Hong Kong)

    2010-10-01

    Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) fibers containing carbonated hydroxyapatite (CHA) nanoparticles with different CHA amounts (5, 10 and 15 wt%) were electrospun with the aid of ultrasonic power for dispersing the nanoparticles. Scanning electron microscopy and energy-dispersive x-ray spectroscopy results showed that the distribution of CHA within the CHA/PHBV nanocomposite fibers was homogeneous when the CHA content was 10 wt%. Slight particle agglomeration occurred when the CHA content was 15 wt%. The diameters of the electrospun CHA/PHBV nanocomposite fibers and PHBV polymer fibers were around 3 {mu}m. Fourier transform infrared spectroscopic analysis further confirmed the presence of CHA in CHA/PHBV nanocomposite fibers. Both PHBV and CHA/PHBV fibrous membranes exhibited similar tensile properties. Compared with PHBV solvent-cast film, the PHBV fibrous membrane was hydrophobic but the incorporation of CHA nanoparticles dramatically enhanced its wettability. In vitro studies revealed that both types of electrospun fibrous membranes (PHBV and CHA/PHBV) supported the proliferation of human osteoblastic cells (SaOS-2). The alkaline phosphatase activity of SaOS-2 cells seeded on the CHA/PHBV fibrous membranes was higher than that of the cells seeded on the PHBV fibrous membranes after 14 days of cell culture. The electrospun CHA/PHBV nanocomposite fibrous membranes show promises for bone tissue engineering applications.

  20. In situ synthesis and modification of calcium carbonate nanoparticles via a bobbling method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Modified calcium carbonate (CaCO3) nanoparticles with cubic- and spindle-like configuration were synthesized in situ by the typical bobbling (gas-liquid-solid) method. The modifiers, such as sodium stearate, octadecyl dihydrogen phosphate (ODP) and oleic acid (OA), were used to obtain hydrophobic nanoparticles. The different modification effects of the modifiers were investigated by measuring the active ratio, whiteness and the contact angle. Moreover, transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetry analysis (TGA analysis) were employed to characterize the obtained products. A preliminary reaction mechanism was discussed. According to the results, the active ratio of CaCO3 modified by ODP was ca. 99.9% and the value of whiteness was 97.3% when the dosage of modifiers reached 2%. The contact angle was 122.25° for the CaCO3 modified in the presence of sodium stearate, ODP and OA. When modified CaCO3 was filled into PVC, the mechanical properties of products were improved greatly such as rupture intensity, pull intensity and fuse temperature. The compatibility and affinity between the modified CaCO3 nanoparticles and the organic matrixes were greatly improved.

  1. Radiosensitizing effect of gold nanoparticles in carbon ion irradiation of human cervical cancer cells

    International Nuclear Information System (INIS)

    Noble metal nanoparticles have received considerable attention in biotechnology for their role in bio sensing due to surface plasmon resonance, medical diagnostics due to better imaging contrast and therapy. The radiosensitization effect of gold nanoparticles (AuNP) has been gaining popularity in radiation therapy of cancer cells. The better depth dose profile of energetic ion beam proves its superiority over gamma radiation for fighting against cancer. In the present work, the glucose capped gold nanoparticles (Glu-AuNP) were synthesised and internalized in the HeLa cells. Transmission electron microscopic analysis of ultrathin sections of Glu-AuNP treated HeLa cells confirmed the internalization of Glu-AuNPs. Control HeLa cells and Glu-AuNp treated HeLa cells were irradiated at different doses of 62 MeV 12C ion beam (LET – 290keV/μm) at BIO beam line of using 15UD Pelletron accelerator at Inter University Accelerator Centre, New Delhi, India. The survival fraction was assessed by colony forming assay which revealed that the dose of carbon ion for 90% cell killing in Glu-AuNP treated HeLa cells and control HeLa cells are 2.3 and 3.2 Gy respectively. This observation shows ∼ 28% reduction of 12C6+ ion dose for Glu-AuNP treated HeLa cells as compared to control HeLa cells

  2. Activated carbons impregnated with iron oxide nanoparticles for enhanced removal of bisphenol A and natural organic matter.

    Science.gov (United States)

    Park, Hak-Soon; Koduru, Janardhan Reddy; Choo, Kwang-Ho; Lee, Byungwhan

    2015-04-01

    The removal of bisphenol A (BPA) is important for the provision of safe drinking water, but its removal in the presence of natural organic matter (NOM) is challenging. Thus, the present study involved the fabrication and characterization of powdered activated carbons impregnated with iron oxide nanoparticles (IONPACs) with respect to the simultaneous removal of BPA and NOM. The number of Fe ions loaded into the PAC pores was optimized in terms of exposure time. Impregnation with iron oxide reduced the surface area and pore volume, but the pore size was maintained. IONPAC adsorbents had considerably greater sorption capabilities for BPA and NOM compared to native, bare PAC particles. The adsorption capacities of BPA and NOM were in the following sequence: bare PAC

  3. Synthesis of carbon nanoparticles using one step green approach and their application as mercuric ion sensor

    Energy Technology Data Exchange (ETDEWEB)

    Roshni, V.; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Carbon nanoparticles (CNPs) have been evolved as a promising candidate for the metal sensing applications due to their synthesis from naturally occurring and easily available non-toxic molecular precursors by green chemistry. A simple and one step procedure is reported here for the synthesis of CNPs from coconut milk by thermal pyrolysis at a temperature of 120–150 °C for 2–5 min without using any carbonizing or passivating agent. On pyrolysis the coconut oil is separated from the carbon rich residue and the residue when dissolved in water showed blue fluorescence under UV light. The CNPs produced are found to show an emission maximum at 440 nm when excited at 360 nm. Synthesis by green approach makes CNPs a promising substitute for the metal sensing applications. Series of metal ions which have a hazardous impact on the ecological system have been taken for the analysis and it is observed that the fluorescence of CNPs gets remarkably quenched by mercuric ions. Fluorescence quenching was studied using standard Stern–Volmer quenching model. Limit of detection was found to be 16.5 nM Hg{sup 2+} concentration. - Highlights: • Green and economical synthesis of carbon nanoparticles (CNPs) from naturally abundant material. • Coconut milk is used as molecular precursor, which on thermal pyrolysis at 120 °C yielded CNPs. • Highly fluorescent CNPs show an emission maxima of 440 nm when excited at 360 nm. • Application of CNPs for metal ion sensing using fluorescence quenching phenomena. • Hg{sup 2+} is most effectively sensed with a detection limit of 16.5 nM.

  4. Synthesis of carbon nanoparticles using one step green approach and their application as mercuric ion sensor

    International Nuclear Information System (INIS)

    Carbon nanoparticles (CNPs) have been evolved as a promising candidate for the metal sensing applications due to their synthesis from naturally occurring and easily available non-toxic molecular precursors by green chemistry. A simple and one step procedure is reported here for the synthesis of CNPs from coconut milk by thermal pyrolysis at a temperature of 120–150 °C for 2–5 min without using any carbonizing or passivating agent. On pyrolysis the coconut oil is separated from the carbon rich residue and the residue when dissolved in water showed blue fluorescence under UV light. The CNPs produced are found to show an emission maximum at 440 nm when excited at 360 nm. Synthesis by green approach makes CNPs a promising substitute for the metal sensing applications. Series of metal ions which have a hazardous impact on the ecological system have been taken for the analysis and it is observed that the fluorescence of CNPs gets remarkably quenched by mercuric ions. Fluorescence quenching was studied using standard Stern–Volmer quenching model. Limit of detection was found to be 16.5 nM Hg2+ concentration. - Highlights: • Green and economical synthesis of carbon nanoparticles (CNPs) from naturally abundant material. • Coconut milk is used as molecular precursor, which on thermal pyrolysis at 120 °C yielded CNPs. • Highly fluorescent CNPs show an emission maxima of 440 nm when excited at 360 nm. • Application of CNPs for metal ion sensing using fluorescence quenching phenomena. • Hg2+ is most effectively sensed with a detection limit of 16.5 nM

  5. A novel enzymatic glucose sensor based on Pt nanoparticles-decorated hollow carbon spheres-modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Luhana, Charles; Bo Xiangjie; Ju Jian; Guo Liping, E-mail: guolp078@nenu.edu.cn [Northeast Normal University, Faculty of Chemistry (China)

    2012-10-15

    A new glucose biosensor was developed based on hollow carbon spheres decorated with platinum nanoparticles (Pt/HCSs)-modified glassy carbon electrode immobilized with glucose oxidase (GOx) with the help of Nafion. The Pt nanoparticles were well dispersed on the HCSs with an average size of 2.29 nm. The detection of glucose was achieved via electrochemical detection of the enzymatically liberated H{sub 2}O{sub 2} at +0.5 V versus Ag/AgCl at physiologic pH of 7.4. The Pt/HCSs-modified electrode exhibited excellent electrocatalytic activities toward both the oxidation and reduction of H{sub 2}O{sub 2}. The glucose biosensor showed good electrocatalytic performance in terms of high sensitivity (4.1 {mu}A mM{sup -1}), low detection limit (1.8 {mu}M), fast response time <3 s, and wide linear range (0.04-8.62 mM). The apparent Michaelis-Menten constant (K{sub m}) and the maximum current density (i{sub max}) values for the biosensor were 10.94 mM and 887 {mu}A cm{sup -2} respectively. Furthermore, this biosensor showed an acceptable reproducibility and high stability. The interfering signals from ascorbic acid and uric acid at concentration levels normally found in human blood were not much compared with the response to glucose. Blood serum samples were also tested with this biosensor and a good recovery was achieved for the two spiked serum samples.

  6. Cobalt nanoparticle-embedded carbon nanotube/porous carbon hybrid derived from MOF-encapsulated Co3O4 for oxygen electrocatalysis.

    Science.gov (United States)

    Dou, Shuo; Li, Xingyue; Tao, Li; Huo, Jia; Wang, Shuangyin

    2016-08-11

    We successfully obtained a novel bi-functional electrocatalyst towards the ORR and OER: Co nanoparticle-embedded N-doped carbon nanotube (CNT)/porous carbon (PC) by pyrolyzing metal organic framework (MOF) encapsulated Co3O4. The as-obtained hybrid exhibited highly efficient electrocatalytic activity for the ORR and OER. Furthermore, the assembled Zn-air batteries also revealed promising performance and long-term stability. PMID:27411845

  7. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rong

    2015-06-01

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  8. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    International Nuclear Information System (INIS)

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  9. A qualitative approach to risk assessment and control in engineered nanoparticles occupational exposure

    OpenAIRE

    Silva, Francisco António Coelho e

    2016-01-01

    Doctoral Dissertation for PhD degree in Industrial and Systems Engineering The existing research effort and common use of nanomaterials, that are an opportunity for economic growth, pose health and safety problems. The research on the nanoparticles health effects performed during the last decade shows the possible harmfulness of several nanoparticles, including those already present in everyday use products, thus worker’s health and safety are critical to the development of nan...

  10. Synthesis and energy transfer within carbon-based fluorescent rare earth nanoparticles and nanocomposites (Conference Presentation)

    Science.gov (United States)

    Yust, Brian G.; Chipara, Mircea; Saenz, Aaron

    2016-03-01

    Recently, there has been a great deal of interest in fluorescent and upconverting rare earth-based nanoparticles for biomedical imaging and photodynamic therapy applications. While many of the widely explored upconverting contrast agents are comprised of fluoride or oxide crystal structures, very little work has been done to investigate the up- and downconversion emission in rare earth-doped carbon nanocomposites. Of particular interest, graphene-UCNP nanocomposites and sesquicarbide nanoparticles may offer a wide range of new applications when coupled with the extraordinary optical properties of rare earth-doped systems, such as potential use as nano-transducers. Carbon-based nanocomposites and sesquicarbides doped with rare earth elements were synthesized using the microwave and solvothermal methods with additional brief high temperature heat treatments. They were then characterized by XRD, visible and NIR excitation and emission spectroscopy, as well as Raman spectrsocopy. Tuning of the emission manifold ratios was explored through different compositions and size. Also, energy transfer between the emitting ions and the electronic states of the host structure was explored. Finally, cytotoxicity was tested, and cellular uptake of these nanomaterials was performed with confocal microscopy.

  11. Gas sensing properties of multiwall carbon nanotubes decorated with Rh nanoparticles

    CERN Document Server

    Leghrib, Radouane; Demoisson, Frédéric; Claessens, Nicolas; Reniers, François; Llobet, Eduard

    2016-01-01

    In the present work, multiwalled carbon nanotubes were decorated with rhodium nanoparticles using a colloidal solution in the post-discharge of an RF atmospheric plasma of argon (Ar) or argon/oxygen (Ar:O$_2$). The properties of these hybrid materials towards the room temperature detection of NO$_2$, C$_2$H$_4$, CO, C$_6$H$_6$ and moisture were investigated and discussed in view of compositional and morphological studies. It was found that the presence of oxygen in the plasma treatment is essential to significantly enhance the gas response of Rh-decorated multiwalled carbon nanotubes and to avoid response saturation even at low gas/vapor concentrations. These desirable effects are attributed to the presence of oxygen during the CNT plasma treatment since oxygenated vacancies act both as active adsorption sites for gases and as anchoring sites for Rh nanoparticles (the presence of Rh nanoclusters is nearly doubled in Ar-O$_2$ treated samples as compared to Ar treated samples). The oxygen treatment also makes e...

  12. Fluorescent carbon nanoparticles: A low-temperature trypsin-assisted preparation and Fe(3+) sensing.

    Science.gov (United States)

    Feng, Jie; Chen, Yonglei; Han, Yangxia; Liu, Juanjuan; Ren, Cuiling; Chen, Xingguo

    2016-07-01

    In recent years, extensive researches are focused on the fluorescent carbon nanoparticles (CNPs) due to their excellent photochemical, biocompatible and water-soluble properties. However, these synthesis methods are generally suffered from tedious processes. In this paper, fluorescent carbon nanoparticles are synthesized by a facile, one-pot, low-temperature method with trypsin and dopamine as precursors. The synthesis process avoids any heating operation and organic solvent, which provides a "green" and effective preparation route. The obtained CNPs exhibit excellent water-solubility, salt-tolerance and photostability. Based on the synergistic action of the inner filter effect and static quenching mechanism, the CNPs are exploited as a "turn-off" fluorescence sensor for sensitive and selective detection of Fe(3+) ions. The probe shows a wide linear range from 0.1 to 500 μM, with a limit of detection of 30 nM. Furthermore, the as-fabricated fluorescent sensing system is successfully applied to the analysis of Fe(3+) in biological samples such as human urine and serum samples with satisfactory recoveries (92.8-113.3%). PMID:27216399

  13. Embedding tin nanoparticles in micron-sized disordered carbon for lithium- and sodium-ion anodes

    International Nuclear Information System (INIS)

    Herein, a new and facile synthesis of a tin-carbon nanocomposite and its electrochemical characterization is presented. Tin nanoparticles were embedded in micron-sized carbonaceous particles, thus successfully preventing the aggregation of tin nanoparticles and buffering the occurring volume strain, which accompanies the reversible (de-)alloying process. Such active material presents specific capacities of around 440 and 390 mAh g−1 for applied specific currents of 0.1 and 0.2 A g−1, respectively, as lithium-ion anode using environmentally friendly and cost-efficient carboxymethyl cellulose as binder. Even more remarkably, at very high specific currents of 2, 5, and 10 A g−1, electrodes based on this composite still offer specific capacities of about 280, 240, and 187 mAh g−1, respectively. In addition, this tin-carbon nanocomposite appears highly promising as anode material for sodium-ion batteries, showing very stable cycling performance in a suitable potential range, and specific capacities of more than 180, 150, 130, and 90 mAh g−1 for an applied specific current of 12.2, 122, 244, and 610 mA g−1, respectively, thus highlighting the high versatility of this composite active material for both Li-ion and Na-ion battery technologies

  14. Preparation and electrochemical properties of gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yu Aimin, E-mail: aiminyu@swin.edu.au [College of Chemical and Environmental Engineering, Hubei Normal University, 435002 (China); Faculty of Life and Social Sciences, Swinburne University of Technology, Melbourne, VIC 3122 (Australia); Zhang Xing [College of Chemical and Environmental Engineering, Hubei Normal University, 435002 (China); School of Chemical and Mathematic Sciences, Murdoch University, Perth, WA 6150 (Australia); Zhang Haili; Han, Deyan [College of Chemical and Environmental Engineering, Hubei Normal University, 435002 (China); Knight, Allan R. [School of Chemical and Mathematic Sciences, Murdoch University, Perth, WA 6150 (Australia)

    2011-10-30

    Highlights: > Gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films were prepared via layer-by-layer self-assembly technique. > The electron transfer behaviour of the hybrid thin films were investigated using an electrochemical probe. > The resulting thin films exhibited an electrocatalytic activity towards the oxidation of nitric oxide. - Abstract: Multi-walled carbon nanotubes (MWCNT)/polyelectrolyte (PE) hybrid thin films were fabricated by alternatively depositing negatively charged MWCNT and positively charged (diallyldimethylammonium chloride) (PDDA) via layer-by-layer (LbL) assembly technique. The stepwise growth of the multilayer films of MWCNT and PDDA was characterized by UV-vis spectroscopy. Scanning electron microscopy (SEM) images indicated that the MWCNT were uniformly embedded in the film to form a network and the coverage density of MWCNT increased with layer number. Au nanoparticles (NPs) could be further adsorbed onto the film to form PE/MWCNT/Au NPs composite films. The electron transfer behaviour of multilayer films with different compositions were studied by cyclic voltammetry using [Fe(CN){sub 6}]{sup 3-/4-} as an electrochemical probe. The results indicated that the incorporation of MWCNT and Au NPs not only greatly improved the electronic conductivity of pure polyelectrolyte films, but also provided excellent electrocatalytic activity towards the oxidation of nitric oxide (NO).

  15. Electrodeposition of Platinum and Ruthenium Nanoparticles in Multiwalled Carbon Nanotube-Nafion Nanocomposite for Methanol Electrooxidation

    Directory of Open Access Journals (Sweden)

    Yu-Chen Tsai

    2009-01-01

    Full Text Available PtRu nanoparticles with a diameter of 10–15 nm were electrodeposited within multiwalled carbon nanotube-Nafion (MWCNT-Nafion nanocomposite. The formation of PtRu nanoparticles in MWCNT-Nafion nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The electrocatalytic activity towards the methanol electrooxidation at PtRu-MWCNT-Nafion and Pt-MWCNT-Nafion nanocomposite-modified glassy carbon electrodes was investigated by cyclic voltammetry. The results indicated that the PtRu-MWCNT-Nafion nanocomposite was electrocatalytically more active than Pt-MWCNT-Nafion nanocomposite. The effect of atomic ratio of Pt : Ru on the electrocatalytic ability towards the methanol electrooxidation was investigated in order to achieve a high catalyst use. The PtRu bimetallic catalyst with 1 : 1 atomic ratio showed better electrocatalytic activity towards the methanol electrooxidation. The stability for the methanol electrooxidation at PtRu-MWCNT-Nafion nanocomposite modified was also investigated.

  16. Three-dimensional heterostructure of metallic nanoparticles and carbon nanotubes as potential nanofiller

    Science.gov (United States)

    Kim, Whi Dong; Huh, Jun Young; Ahn, Ji Young; Lee, Jae Beom; Lee, Dongyun; Hong, Suck Won; Kim, Soo Hyung

    2012-03-01

    The effect of the dimensionality of metallic nanoparticle-and carbon nanotube-based fillers on the mechanical properties of an acrylonitrile butadiene styrene (ABS) polymer matrix was examined. ABS composite films, reinforced with low dimensional metallic nanoparticles (MNPs, 0-D) and carbon nanotubes (CNTs, 1-D) as nanofillers, were fabricated by a combination of wet phase inversion and hot pressing. The tensile strength and elongation of the ABS composite were increased by 39% and 6%, respectively, by adding a mixture of MNPs and CNTs with a total concentration of 2 wt%. However, the tensile strength and elongation of the ABS composite were found to be significantly increased by 62% and 55%, respectively, upon addition of 3-D heterostructures with a total concentration of 2 wt%. The 3-D heterostructures were composed of multiple CNTs grown radially on the surface of MNP cores, resembling a sea urchin. The mechanical properties of the ABS/3-D heterostructured nanofiller composite films were much improved compared to those of an ABS/mixture of 0-D and 1-D nanofillers composite films at various filler concentrations. This suggests that the 3-D heterostructure of the MNPs and CNTs plays a key role as a strong reinforcing agent in supporting the polymer matrix and simultaneously serves as a discrete force-transfer medium to transfer the loaded tension throughout the polymer matrix.

  17. Synthesis and Capacitive Properties of Manganese Oxide Nanoparticles Dispersed on Hierarchical Porous Carbons

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted - Highlights: • By contrast with template methods, HPCs are obtained by activation of humic acid, which is simple and cost-effective. • HPCs are rich in oxygen-containing functional groups, which allow the formation and uniform anchoring of fine MnO2 via strong chemical interactions between the functional groups of HPCs and the nanomaterials. - Abstract: A growing manganese dioxide (MnO2) nanoparticles on hierarchical porous carbons (HPCs) is conducted via a simple route starting with KMnO4 and ethanol aimed to enhance the electrochemically active surface area of MnO2. It is found that these MnO2 nanoparticles are uniformly grown on the external surface of the HPCs and still maintain hierarchical porous structure, yielding a composite electrode showing good electron transport, rapid ion penetration, fast and reversible Faradic reaction when used as supercapacitor electrode materials. HPCs–MnO2 composite displays the specific capacitance as high as 167 F g−1 and 192 F cm−3 in 3 M KOH aqueous electrolyte and 94 F g−1 and 113 F cm−3 in 1 M tetraethylammonium tetrafluoroborate/propylene carbonate (Et4NBF4/PC) organic electrolyte. Furthermore, it also exhibits a superior cycling stability with 96% retention of the initial specific capacitance after 1000 cycles and stable Coulombic efficiency of 99% in 3 M KOH measured using the galvanostatic charge–discharge technique

  18. Nanocomposite of Au Nanoparticles/Helical Carbon Nanofibers and Application in Hydrogen Peroxide Biosensor.

    Science.gov (United States)

    Zhai, Mumu; Cui, Rongjing; Gu, Ning; Zhang, Genhua; Lin, Wang; Yu, Lingjun

    2015-06-01

    A combined sol-gel/hydrogen reduction method has been developed for the mass production of helical carbon nanofibers (HCNFs) by the pyrolysis of acetylene at 425 degrees C in the presence of NiO nanoparticles. The synthesized HCNFs were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The helical-structured carbon nanofibers have a large specific surface area and excellent biocompatibility. A novel enzymatic hydrogen peroxide sensor was then successfully fabricated based on the nanocomposites containing HCNFs and gold nanoparticles (AuNPs). The results indicated that the Au/HCNFs nanocomposites exhibited excellent electrocatalytic activity to the reduction of H2O2, offering a wide linear range from 1.0 μM to 3157 μM with a detection limit as low as 0.46 μM. The apparent Michaelis-Menten constant of the biosensor was 0.61 mM. The as-fabricated biosensor showed a rapid and sensitive amperometric response to hydrogen peroxide with acceptable preparation reproducibility and excellent stability. Because of their low cost and high stability, these novel HCNFs represent seem to be a kind of promising biomaterial and may find wide new applications in scopes such as biocatalysis, immunoassay, environmental monitoring and so on. PMID:26369097

  19. Oxygen Reduction Electrocatalysts Based on Coupled Iron Nitride Nanoparticles with Nitrogen-Doped Carbon

    Directory of Open Access Journals (Sweden)

    Min Jung Park

    2016-06-01

    Full Text Available Aimed at developing a highly active and stable non-precious metal electrocatalyst for oxygen reduction reaction (ORR, a novel FexNy/NC nanocomposite—that is composed of highly dispersed iron nitride nanoparticles supported on nitrogen-doped carbon (NC—was prepared by pyrolyzing carbon black with an iron-containing precursor in an NH3 atmosphere. The influence of the various synthetic parameters such as the Fe precursor, Fe content, pyrolysis temperature and pyrolysis time on ORR performance of the prepared iron nitride nanoparticles was investigated. The formed phases were determined by experimental and simulated X-ray diffraction (XRD of numerous iron nitride species. We found that Fe3N phase creates superactive non-metallic catalytic sites for ORR that are more active than those of the constituents. The optimized Fe3N/NC nanocomposite exhibited excellent ORR activity and a direct four-electron pathway in alkaline solution. Furthermore, the hybrid material showed outstanding catalytic durability in alkaline electrolyte, even after 4,000 potential cycles.

  20. Effect of BaTiO3 nano-particles on breakdown performance of propylene carbonate

    Science.gov (United States)

    Hou, Yanpan; Zhang, Zicheng; Zhang, Jiande; Liu, Zhuofeng; Song, Zuyin

    2015-05-01

    As an alternative to water, propylene carbonate (PC) has a good application prospect in the compact pulsed power sources for its breakdown strength higher than that of water, resistivity bigger than 109 Ω m, and low freezing temperature (-49 °C). In this paper, the investigation into dielectric breakdown of PC and PC-based nano-fluids (NFs) subjected to high amplitude electric field is presented with microsecond pulses applied to a 1 mm gap full of PC or NFs between spherical electrodes. One kind of NF is composed of PC mixed with 0.5-1.4 vol. % BaTiO3 (BT) nano-particles of mean diameter ≈100 nm and another is mixed with 0.3-0.8 vol. % BT nano-particles of mean diameter ≈30 nm. The experimental results demonstrate the rise of permittivity and improvement of the breakdown strength of NFs compared with PC. Moreover, it is found that there exists an optimum fraction for these NFs corresponding to tremendous surface area in nano-composites with finite mesoscopic thickness. In concrete, the dielectric breakdown voltage of NFs is 33% higher than that of PC as the volume concentration of nano-particles with a 100 nm diameter is 0.9% and the breakdown voltage of NFs is 40% higher as the volume concentration of nano-particles with a 30 nm diameter is 0.6%. These phenomena are considered as the dielectric breakdown voltage of PC-based NFs is increased because the interfaces between nano-fillers and PC matrices provide myriad trap sites for charge carriers, which play a dominant role in the breakdown performance of NFs.