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Sample records for airborne engineered nanoparticles

  1. Exposure to airborne engineered nanoparticles in the indoor environment

    NASA Astrophysics Data System (ADS)

    Vance, Marina E.; Marr, Linsey C.

    2015-04-01

    This literature review assesses the current state of knowledge about inhalation exposure to airborne, engineered nanoparticles in the indoor environment. We present principal exposure scenarios in indoor environments, complemented by analysis of the published literature and of an inventory of nanotechnology-enhanced consumer products. Of all products listed in the inventory, 10.8% (194 products) present the potential for aerosolization of nanomaterials and subsequent inhalation exposure during use or misuse. Among those, silver-containing products are the most prevalent (68 products). Roughly 50% of products would release wet aerosols and 50% would potentially release dry aerosols. Approximately 14% are cleaning products that can be broadly used in public indoor environments, where building occupants may be exposed. While a variety of nanomaterial compositions have been investigated in the limited number of published release and exposure studies, we identified a need for studies investigating nanofibers (beyond carbon nanotubes), nanofilms, nanoplatelets, and other emerging nanomaterials such as ceria and their nanocomposites. Finally, we provide recommendations for future research to advance the understanding of exposure to airborne nanomaterials indoors, such as studies into indoor chemistry of nanomaterials, better nanomaterial reporting and labeling in consumer products, and safer design of nanomaterial-containing consumer products.

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

    NASA Astrophysics Data System (ADS)

    Asimakopoulou, Akrivi; Daskalos, Emmanouil; Lewinski, Nastassja; Riediker, Michael; Papaioannou, Eleni; Konstandopoulos, Athanasios G.

    2013-04-01

    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.

  3. Functionality Based Detection of Airborne Engineered Nanoparticles in Quasi Real Time: A New Type of Detector and a New Metric

    PubMed Central

    Neubauer, Nicole

    2013-01-01

    A new type of detector which we call the Catalytic Activity Aerosol Monitor (CAAM) was investigated towards its capability to detect traces of commonly used industrial catalysts in ambient air in quasi real time. Its metric is defined as the catalytic activity concentration (CAC) expressed per volume of sampled workplace air. We thus propose a new metric which expresses the presence of nanoparticles in terms of their functionality - in this case a functionality of potential relevance for damaging effects - rather than their number, surface, or mass concentration in workplace air. The CAAM samples a few micrograms of known or anticipated airborne catalyst material onto a filter first and then initiates a chemical reaction which is specific to that catalyst. The concentration of specific gases is recorded using an IR sensor, thereby giving the desired catalytic activity. Due to a miniaturization effort, the laboratory prototype is compact and portable. Sensitivity and linearity of the CAAM response were investigated with catalytically active palladium and nickel nano-aerosols of known mass concentration and precisely adjustable primary particle size in the range of 3–30nm. With the miniature IR sensor, the smallest detectable particle mass was found to be in the range of a few micrograms, giving estimated sampling times on the order of minutes for workplace aerosol concentrations typically reported in the literature. Tests were also performed in the presence of inert background aerosols of SiO2, TiO2, and Al2O3. It was found that the active material is detectable via its catalytic activity even when the particles are attached to a non-active background aerosol. PMID:23504803

  4. Determination of airborne nanoparticles from welding operations.

    PubMed

    Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

    2012-01-01

    The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers. PMID:22788362

  5. Proteomic analysis of the differentially expressed proteins by airborne nanoparticles.

    PubMed

    Park, Seul Ki; Jeon, Yu Mi; Son, Bu Soon; Youn, Hyung Sun; Lee, Mi Young

    2011-07-01

    Airborne nanoparticles with thermodynamic diameters less than 56 nm (PM(0.056)) were collected using a Moudi cascade impactor, and the differentially expressed proteins upon exposure to the airborne nanoparticles were identified in human bronchial epithelial cells. More than 600 protein spots were detected on the two-dimensional gel, and the identified 13 of these proteins showed notable changes. Nine were up-regulated and four were down-regulated following treatment with the airborne nanoparticles. Notably, malignant transformation-associated multiple forms of keratins, epigenetic regulation-related MBD1-containing chromatin associated factor 2, epithelial malignancy-related vimentin and exocytosis-related annexin A2 were changed upon exposure to airborne nanoparticle PM(0.056). PMID:21491466

  6. NANODEVICE: Novel Concepts, Methods, and Technologies for the Production of Portable, Easy-to-use Devices for the Measurement and Analysis of Airborne Engineered Nanoparticles in Workplace Air

    NASA Astrophysics Data System (ADS)

    Sirviö, Sari; Savolainen, Kai

    2011-07-01

    NANODEVICE is a research project funded by the European Commission in the context of the 7th Framework Programme. The duration is 48 months starting 1st of April 2009. Due to their unique properties, engineered nanoparticles (ENP) are now used for a myriad of novel applications, and have a great economic and technological importance. However, some of these properties, especially their surface reactivity, have raised health concerns due to their potential health effects. There is currently a shortage of field-worthy, cost-effective ways - especially in real time - for reliable assessment of exposure levels to ENP in workplace air. NANODEVICE will provide new information on the physico-chemical properties of engineered nanoparticles (ENP) and information about their toxicology. The main emphasis of the project is in the development of novel measuring devices to assess the exposure to ENP's from workplace air. The purpose of the project is also to promote the safe use of ENP through guidance, standards and education, implementing of safety objectives in ENP production and handling, and promotion of safety related collaborations through an international nanosafety forum. The main project goal is to develop innovative concepts and reliable methods for characterizing ENP in workplace air with novel, portable and easy-to-use devices suitable for workplaces.

  7. Airborne monitoring to distinguish engineered nanomaterials from incidental particles for environmental health and safety.

    PubMed

    Peters, Thomas M; Elzey, Sherrie; Johnson, Ronald; Park, Heaweon; Grassian, Vicki H; Maher, Tabitha; O'Shaughnessy, Patrick

    2009-02-01

    Two methods were used to distinguish airborne engineered nanomaterials from other airborne particles in a facility that produces nano-structured lithium titanate metal oxide powder. The first method involved off-line analysis of filter samples collected with conventional respirable samplers at each of seven locations (six near production processes and one outdoors). Throughout most of the facility and outdoors, respirable mass concentrations were low (<0.050 mg/m(3)) and were attributed to particles other than the nanomaterial (<10% by mass titanium determined with inductively coupled plasma atomic emission spectrometry). In contrast, in a single area with extensive material handling, mass concentrations were greatest (0.118 mg m(-3)) and contained up to 39% +/- 11% lithium titanium, indicating the presence of airborne nanomaterial. Analysis of the filter samples collected in this area by transmission electron microscope and scanning electron microscope revealed that the airborne nanomaterial was associated only with spherical aggregates (clusters of fused 10-80 nm nanoparticles) that were larger than 200 nm. This analysis also showed that nanoparticles in this area were the smallest particles of a larger distribution of submicrometer chain agglomerates likely from welding in an adjacent area of the facility. The second method used two, hand-held, direct-reading, battery-operated instruments to obtain a time series of very fine particle number (<300 nm), respirable mass, and total mass concentration, which were then related to activities within the area of extensive material handling. This activity-based monitoring showed that very fine particle number concentrations (<300 nm) had no apparent correlation to worker activities, but that sharp peaks in the respirable and total mass concentration coincided with loading a hopper and replacing nanomaterial collection bags. These findings were consistent with those from the filter-based method in that they demonstrate

  8. Airborne monitoring to distinguish engineered nanomaterials from incidental particles for environmental health and safety

    PubMed Central

    Peters, TM; Elzey, S; Johnson, R; Park, H; Grassian, VH; Maher, T; O'Shaughnessy, P

    2016-01-01

    Two methods were used to distinguish airborne engineered nanomaterials from other airborne particles in a facility that produces nano-structured lithium titanate metal oxide powder. The first method involved off-line analysis of filter samples collected with conventional respirable samplers at each of seven locations (six near production processes and one outdoors). Throughout most of the facility and outdoors, respirable mass concentrations were low (<0.050 mg m−3) and were attributed to particles other than the nanomaterial (<10% by mass titanium determined with inductively coupled plasma atomic emission spectrometry). In contrast, in a single area with extensive material handling, mass concentrations were greatest (0.118 mg m−3) and contained up to 39% +/− 11% lithium titanium, indicating the presence of airborne nanomaterial. Analysis of the filter samples collected in this area by transmission electron microscope and scanning electron microscope revealed that the airborne nanomaterial was associated only with spherical aggregates (clusters of fused 10–80 nm nanoparticles) that were larger than 200 nm. This analysis also showed that nanoparticles in this area were the smallest particles of a larger distribution of submicrometer chain agglomerates likely from welding in an adjacent area of the facility. The second method used two, hand-held, direct-reading, battery-operated instruments to obtain a time series of very fine particle number (<300 nm), respirable mass, and total mass concentration, which were then related to activities within the area of extensive material handling. This activity-based monitoring showed that very fine particle number concentrations (<300 nm) had no apparent correlation to worker activities, but that sharp peaks in the respirable and total mass concentration coincided with loading a hopper and replacing nanomaterial collection bags. These findings were consistent with those from the filter-based method in that they

  9. Characterization of Airborne Nanoparticle Loss in Sampling Tubing.

    PubMed

    Tsai, Candace Su-Jung

    2015-01-01

    Airborne nanoparticle release has been studied extensively lately using a variety of instruments and nanoparticle loss data for the instrument sampling tubes were required. This study used real-time measurements to characterize particle losses. Particle concentrations were measured by Fast Mobility Particle Sizer (FMPS). Electrically conductive and Tygon sampling tubes 7.7 mm I.D. and 2.0, 4.9, 7.0, and 8.4 m long, were used to analyze particle losses. Two different sources of nearly steady-state particles-atmospheric nanoparticles (maximum concentration of 4,000-6,000 particle/cm(3)) and nebulizer-generated salt aerosols (maximum concentration of 14,000-16,000 particle/cm(3))-were utilized. For all test conditions, a reduction in particle number concentration was observed and found to be proportional to tube length for particle diameter (dp) less than 40 nm. A maximum loss up to 30% was found for the longest tube length (8.4 m) at particle size of approximately 8 nm. For particles from 40 to 400 nm, the losses were less than 3%. Measured particle losses were greater than predicted by theory for the smallest particles. The two types of tubing showed similar particle losses for both test aerosols. Particle losses were low for dp greater than 40 nm, and for all particle sizes when the tube length was less than 2 m. PMID:25746064

  10. Nanoparticle Superlattice Engineering with DNA

    NASA Astrophysics Data System (ADS)

    Macfarlane, Robert John

    developments in DNA-programmed nanoparticle assembly not covered in this thesis, as well as future challenges for this field. Supplementary information to support the conclusions of the thesis, as well as provide technical details on how these materials are synthesized, are provided in appendices at the end of the thesis. As a whole, this methodology presents a major advance towards nanoparticle superlattice engineering, as it effectively separates the identity of a particle core (and thereby its physical properties) from the variables that control its assembly, enabling the synthesis of designer nanoparticle-based materials.

  11. Airborne Nanoparticle Detection By Sampling On Filters And Laser-Induced Breakdown Spectroscopy Analysis

    NASA Astrophysics Data System (ADS)

    Dewalle, Pascale; Sirven, Jean-Baptiste; Roynette, Audrey; Gensdarmes, François; Golanski, Luana; Motellier, Sylvie

    2011-07-01

    Nowadays, due to their unique physical and chemical properties, engineered nanoparticles are increasingly used in a variety of industrial sectors. However, questions are raised about the safety of workers who produce and handle these particles. Therefore it is necessary to assess the potential exposure by inhalation of these workers. There is thereby a need to develop a suitable instrumentation which can detect selectively the presence of engineered nanoparticles in the ambient atmosphere. In this paper Laser-Induced Breakdown Spectroscopy (LIBS) is used to meet this target. LIBS can be implemented on site since it is a fast and direct technique which requires no sample preparation. The approach consisted in sampling Fe2O3 and TiO2 nanoparticles on a filter, respectively a mixed cellulose ester membrane and a polycarbonate membrane, and to measure the surface concentration of Fe and Ti by LIBS. Then taking into account the sampling parameters (flow, duration, filter surface) we could calculate a detection limit in volume concentration in the atmosphere. With a sampling at 10 L/min on a 10 cm2 filter during 1 min, we obtained detection limits of 56 μg/m3 for Fe and 22 μg/m3 for Ti. These figures, obtained in real time, are significantly below existing workplace exposure recommendations of the EU-OSHA and of the NIOSH. These results are very encouraging and will be completed in a future work on airborne carbon nanotube detection.

  12. Fe2O3 nanoparticles for airborne organophosphate detection

    NASA Astrophysics Data System (ADS)

    Phillips, Joshua; Soliz, Jennifer; Hauser, Adam

    Dire need for early detection of organophosphates (OP) exists in both civilian (pesticide/herbicide buildup) and military (G/V nerve agents) spheres. Nanoparticle materials are excellent candidates for the detection and/or decontamination of hazardous materials, owing to their large surface to volume ratios and tailored surface functionality. Within this category, metal oxides include structures that are stable with the range of normal environmental conditions (temperature, humidity), but have strong, specific reaction mechanisms (hydrolysis, oxidation, catalysis, stoichiometric reaction) with toxic compounds. In this talk, we will present on the suitability of Fe2O3 nanoparticles as airborne organophosphate detectors. 23 nm particles were exposed to a series of organophosphate compounds (dimethyl methylphosphonate, dimethyl chlorophosphonate, diisopropyl methylphosphonate), and studied by x-ray magnetic circular dichroism and x-ray absorption spectroscopy to confirm the stoichiometric Fe2O3 to FeO mechanism and determine magnetic sensor feasibility. AC Impedance Spectroscopy shows both high sensitivity and selectivity via frequency dependence in both impedance and resistivity, suggesting some feasibility for impedimetric devices. We acknowledge funding under Army Research Office STIR Award #W911F-15-1-0104. J.R.S. acknowledges funding from the Defense Threat Reduction Agency under Projects BA13PHM210 and BA07PRO104. J.R.S. also acknowledges funding under a NRC fellowship.

  13. Toxicity of Engineered Nanoparticles in the Environment

    PubMed Central

    Maurer-Jones, Melissa A.; Gunsolus, Ian L.; Murphy, Catherine J.; Haynes, Christy L.

    2014-01-01

    While nanoparticles occur naturally in the environment and have been intentionally used for centuries, the production and use of engineered nanoparticles has seen a recent spike, which makes environmental release almost certain. Therefore, recent efforts to characterize the toxicity of engineered nanoparticles have focused on the environmental implications, including exploration of toxicity to organisms from wide-ranging parts of the ecosystem food webs. Herein, we summarize the current understanding of toxicity of engineered nanoparticles to representatives of various trophic levels, including bacteria, plants, and multicellular aquatic/terrestrial organisms, to highlight important challenges within the field of econanotoxicity, challenges that analytical chemists are expertly poised to address. PMID:23427995

  14. Airborne nanoparticle concentrations in the manufacturing of polytetrafluoroethylene (PTFE) apparel.

    PubMed

    Vosburgh, Donna J H; Boysen, Dane A; Oleson, Jacob J; Peters, Thomas M

    2011-03-01

    One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600 °C). This study addressed the potential for exposure to particulate matter from this sealing process by characterizing airborne particles in a facility that produces more than 1000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm⁻³)) compared with that measured in the office area (12,100 particles cm⁻³). Respirable mass concentrations were negligible throughout the facility (GM = 0.002 mg m⁻³) in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p < 0.0001). The sealing workers' breathing zone concentrations ranged from 147,000 particles cm⁻³ to 798,000 particles cm⁻³, and their seam responsibility significantly influenced their breathing zone concentrations (p = 0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations. PMID:21347955

  15. Airborne Nanoparticle Concentrations in the Manufacturing of Polytetrafluoroethylene (PTFE) Apparel

    PubMed Central

    Vosburgh, Donna J.H.; Boysen, Dane A.; Oleson, Jacob J.; Peters, Thomas M.

    2016-01-01

    One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric, using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600°C). This study addressed the potential for exposure to particulate matter from this sealing process, by characterizing airborne particles in a facility that produces over 1,000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm−3) compared to that measured in the office area (12,100 particles cm−3). Respirable mass concentrations were negligible throughout the facility (GM=0.002 mg m−3 in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p<0.0001). The sealing workers’ breathing zone concentrations ranged from 147,000 particles cm−3 to 798,000 particles cm−3, and their seam responsibility significantly influenced their breathing zone concentrations (p=0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations. PMID:21347955

  16. Interfacial functionalization and engineering of nanoparticles

    NASA Astrophysics Data System (ADS)

    Song, Yang

    The intense research interest in nanoscience and nanotechnology is largely fueled by the unique properties of nanoscale materials. In this dissertation, the research efforts are focused on surface functionalization and interfacial engineering of functional nanoparticles in the preparation of patchy nanoparticles (e.g., Janus nanoparticles and Neapolitan nanoparticles) such that the nanoparticle structures and properties may be manipulated to an unprecedented level of sophistication. Experimentally, Janus nanoparticles were prepared by an interfacial engineering method where one hemisphere of the originally hydrophobic nanoparticles was replaced with hydrophilic ligands at the air|liquid or solid|liquid interface. The amphiphilic surface characters of the Janus nanoparticles were verified by contact angle measurements, as compared to those of the bulk-exchange counterparts where the two types of ligands were distributed rather homogeneously on the nanoparticle surface. In a further study, a mercapto derivative of diacetylene was used as the hydrophilic ligands to prepare Janus nanoparticles by using hydrophobic hexanethiolate-protected gold nanoparticles as the starting materials. Exposure to UV irradiation led to effective covalent cross-linking between the diacetylene moieties of neighboring ligands and hence marked enhancement of the structural integrity of the Janus nanoparticles, which was attributable to the impeded surface diffusion of the thiol ligands on the nanoparticle surface, as manifested in fluorescence measurements of aged nanoparticles. More complicated bimetallic AgAu Janus nanoparticles were prepared by interfacial galvanic exchange reactions of a Langmuir-Blodgett monolayer of 1-hexanethiolate-passivated silver nanoparticles on a glass slide with gold(I)-mercaptopropanediol complex in a water/ethanol solution. The resulting nanoparticles exhibited an asymmetrical distribution not only of the organic capping ligands on the nanoparticle surface but

  17. Engineered nanoparticles: thrombotic events in cancer

    NASA Astrophysics Data System (ADS)

    Abdalla, Ahmed M. E.; Xiao, Lin; Ouyang, Chenxi; Yang, Guang

    2014-11-01

    Engineered nanoparticles are being increasingly produced for specific applications in medicine. Broad selections of nano-sized constructs have been developed for applications in diagnosis, imaging, and drug delivery. Nanoparticles as contrast agents enable conjugation with molecular markers which are essential for designing effective diagnostic and therapeutic strategies. Such investigations can also lead to a better understanding of disease mechanisms such as cancer-associated thrombosis which remains unpredictable with serious bleeding complications and high risk of death. Here we review the recent and current applications of engineered nanoparticles in diagnosis and therapeutic strategies, noting their toxicity in relation to specific markers as a target.

  18. MICROBIAL IMPACTS OF ENGINEERED NANOPARTICLES

    EPA Science Inventory

    Reactivity at the nanometric scale is intimately linked to nanoparticle mobility and microbial sensitivity. Thus, first-order factors increasing nanoparticle reactivity should increase the rate of redox reactions with second-order effects on particle mobility and ecot...

  19. Neurotoxicity of engineered nanoparticles from metals.

    PubMed

    Sharma, Hari Shanker; Sharma, Aruna

    2012-02-01

    Human exposure to metal nanoparticles such as silver (Ag), copper (Cu) or aluminum (Al) is very common at work places involving automobile, aerospace industry, gun factories or defense related explosives making. Additional sources of exposure to engineered nanoparticles affecting human health are chemical, electronics and communication industries. The nanoparticles (ca. 20 to 120 nm) easily enter the body through inhalation and are deposited into various tissues and organs including brain, where they could stay there for long periods of time. However, the pathophysiological reactions of nanoparticles in vivo on brain function are still not well known. Previous observations from our laboratory showed that engineered nanoparticles from Ag, Cu or Al (50-60 nm) when administered through systemic or intracerebral routes in rats or mice induce neurotoxicity depending on their type, dose and duration of the exposure. These nanoparticles also altered sensory, motor and cognitive functions at the time of development of brain pathologies. Thus, neuronal, glial, axonal and endothelial cell damages are most pronounced following Ag and Cu intoxication as compared to Al in identical doses that are more pronounced in mice as compared to rats of similar age group. The functional significance of these findings and the probable mechanisms of metal nanoparticle-induced neurotoxicity are discussed in this review largely based on our own investigations. PMID:22229317

  20. Manufactured and Airborne Nanoparticle Cardiopulmonary Interactions: A Review of Mechanisms and the Possible Contribution of Mast Cells

    EPA Science Inventory

    Human inhalation exposures to manufactured nanoparticles (NP) and airborne ultrafine particles (UFP) continues to increase in both occupational and environmental settings. UFP exposures have been associated with increased cardiovascular mortality and morbidity, while ongoing res...

  1. Immunological Assays as an Opportunity of Assessment of Health Risks of Airborne Particle Mixture Including Nanoparticles

    NASA Astrophysics Data System (ADS)

    Brzicová, Táňa; Lochman, Ivo; Danihelka, Pavel; Lochmanová, Alexandra; Lach, Karel; Mička, Vladimír

    2013-04-01

    The aim of this pilot study was to evaluate perspectives of the assessment of nonspecific biological effects of airborne particulate matter including nanoparticles using appropriate immunological assays. We have selected various in vitro immunological assays to establish an array allowing us to monitor activation of the cell-mediated and humoral response of both the innate and adaptive immunity. To assess comprehensive interactions and effects, the assays were performed in whole blood cultures from healthy volunteers and we used an original airborne particle mixture from high pollution period in Ostrava region representing areas with one of the most polluted air in Europe. Even if certain effects were observed, the results of the immunological assays did not prove significant effects of airborne particles on immune cells' functions of healthy persons. However, obtained data do not exclude health risks of long-term exposure to airborne particles, especially in case of individuals with genetic predisposition to certain diseases or already existing disease. This study emphasizes the in vitro assessment of complex effects of airborne particles in conditions similar to actual ones in an organism exposed to particle mixture present in the polluted air.

  2. Removal of Airborne Nanoparticles by Membrane Coated Filters

    PubMed Central

    Liu, Jingxian; Pui, David Y. H.; Wang, Jing

    2011-01-01

    The increasing amount of nanoparticles with the development of nanotechnology gives rise to concerns about potential negative impact on the environment and health hazards posed to humans. Membrane filter is an effective media to control nanoparticles. Three filters coated with polytetrafluoroethylene (PTFE) membrane were investigated in this study. A series of experiments on the filter efficiency and relevant parameters such as the particle size and face velocity were carried out. The data show that the efficiency curves for the membrane filters demonstrate the typical shape of “v” for particle sizes from 10 to 300 nm at face velocities from 0.3 to 15 cm/s. Membrane filters with larger pore sizes have larger Most Penetrating Particles Sizes (MPPS), and the MPPS decreases with increasing face velocity. The efficiencies decrease with increasing face velocity for particle sizes from 10 to 300 nm. We present the filtration efficiency data as a novel three-dimensional graph to illustrate its dependence on the particle size and face velocity. The membrane coated filter can be considered as two combined layers, one fibrous layer and one membrane layer. We develop a new filtration efficiency model which is a combination of the models for the two layers. Results from the model calculation agree with experimental data well. The study can help to optimize the filter product and to determine the operational parameters of filters, thus contributing to reduction of air pollution by rapidly emerging nanoparticles. PMID:21889783

  3. Environmental Transformations of Engineered Nanoparticles: Implications for Nanoparticle Transport

    NASA Astrophysics Data System (ADS)

    Lowry, G. V.; Levard, C.; Reinsch, B.; Ma, R.; Kirschling, T.; Brown, G. E.; Tilton, R.

    2011-12-01

    Geochemical transformations that engineered nanomaterials (ENMs) may undergo in different environments very poorly characterized. Sulfidation of metallic nanoparticles (NPs), particularly class B soft metals such as Ag NPs, is expected in the environment. Transformation will alter the surface properties and fate of Ag NPs. ENMs are often coated with a polymeric coating to prevent aggregation or to provide specific functionality. These coatings dramatically impact their transport properties. The potential for biological processes to remove covalently bound polymeric coatings from nanoparticles, and the effect of coating loss on the particle's transport properties is not known. The objectives of this work were to 1) better understand the environmental conditions that would promote sufidation of class B soft metal nanoparticles (Ag NPs and ZnO NPs), and to determine the effect that this has on their surface properties and aggregation potential, and 2) to determine if microbes can access covalently bound polymeric coatings from an engineered NP, and the effect on their surface properties and aggregation potential. Ag and ZnO NPs were synthesized and characterized for size, shape, coating mass, charge, crystal structure, and chemical composition using a range of analytical methods (TEM, DLS, TGA, EPM, XAS). These particles were sulfidized in the laboratory, biosolids, and wetland soils and the transformed materials were characterized. Sulfidation was rapid in all cases and resulted in a mixed crystalline/amorphous Ag2S/Ag2O particle depending on the ratio of Ag to HS- in the system. Sulfidation decreased surface charge and displayed significant aggregation compared to the unsulfidized materials. Sulfidation also occurred in biosolids and in wetland soils. Polymer coatings covalently bound to ENMs are bioavailable. Model poly(ethylene oxide) (PEO) brush-coated nanoparticles (30 nm hydrodynamic radius) were synthesized to obtain a nanomaterial in which biodegradation was

  4. Real-time single airborne nanoparticle detection with nanomechanical resonant filter-fiber

    PubMed Central

    Schmid, Silvan; Kurek, Maksymilian; Adolphsen, Jens Q.; Boisen, Anja

    2013-01-01

    Nanomechanical resonators have an unprecedented mass sensitivity sufficient to detect single molecules, viruses or nanoparticles. The challenge with nanomechanical mass sensors is the direction of nano-sized samples onto the resonator. In this work we present an efficient inertial sampling technique and gravimetric detection of airborne nanoparticles with a nanomechanical resonant filter-fiber. By increasing the nanoparticle momentum the dominant collection mechanism changes from diffusion to more efficient inertial impaction. In doing so we reach a single filter-fiber collection efficiency of 65 ± 31% for 28 nm silica nanoparticles. Finally, we show the detection of single 100 nm silver nanoparticles. The presented method is suitable for environmental or security applications where low-cost and portable monitors are demanded. It also constitutes a unique technique for the fundamental study of single filter-fiber behavior. We present the direct measurement of diffusive nanoparticle collection on a single filter-fiber qualitatively confirming Langmuir's model from 1942. PMID:23411405

  5. Recent advances in benefits and hazards of engineered nanoparticles.

    PubMed

    Radad, Khaled; Al-Shraim, Mubarak; Moldzio, Rudolf; Rausch, Wolf-Dieter

    2012-11-01

    Over recent decades, engineered nanoparticles are increasingly produced as the result of the rapid development in nanotechnology. They are currently used in a wide range of industrial and public sectors including healthcare, agriculture, transport, energy, materials, and information and communication technologies. As the result, an increasing concern has been raised over the potential impacts of engineered nanoparticles to human health. In the light of this, it is the purpose of the present review to discuss: (1) novel properties of engineered nanoparticles particularly in biomedical sciences, (2) most recently reported adverse effects of manufactured nanoparticles on human health and (3) different aspects of toxicological risk assessment of these nanoparticles. PMID:22964156

  6. Optimization of nanoparticles for cardiovascular tissue engineering.

    PubMed

    Izadifar, Mohammad; Kelly, Michael E; Haddadi, Azita; Chen, Xiongbiao

    2015-06-12

    Nano-particulate delivery systems have increasingly been playing important roles in cardiovascular tissue engineering. Properties of nanoparticles (e.g. size, polydispersity, loading capacity, zeta potential, morphology) are essential to system functions. Notably, these characteristics are regulated by fabrication variables, but in a complicated manner. This raises a great need to optimize fabrication process variables to ensure the desired nanoparticle characteristics. This paper presents a comprehensive experimental study on this matter, along with a novel method, the so-called Geno-Neural approach, to analyze, predict and optimize fabrication variables for desired nanoparticle characteristics. Specifically, ovalbumin was used as a protein model of growth factors used in cardiovascular tissue regeneration, and six fabrication variables were examined with regard to their influence on the characteristics of nanoparticles made from high molecular weight poly(lactide-co-glycolide). The six-factor five-level central composite rotatable design was applied to the conduction of experiments, and based on the experimental results, a geno-neural model was developed to determine the optimum fabrication conditions. For desired particle sizes of 150, 200, 250 and 300 nm, respectively, the optimum conditions to achieve the low polydispersity index, higher negative zeta potential and higher loading capacity were identified based on the developed geno-neural model and then evaluated experimentally. The experimental results revealed that the polymer and the external aqueous phase concentrations and their interactions with other fabrication variables were the most significant variables to affect the size, polydispersity index, zeta potential, loading capacity and initial burst release of the nanoparticles, while the electron microscopy images of the nanoparticles showed their spherical geometries with no sign of large pores or cracks on their surfaces. The release study revealed

  7. Optimization of nanoparticles for cardiovascular tissue engineering

    NASA Astrophysics Data System (ADS)

    Izadifar, Mohammad; Kelly, Michael E.; Haddadi, Azita; Chen, Xiongbiao

    2015-06-01

    Nano-particulate delivery systems have increasingly been playing important roles in cardiovascular tissue engineering. Properties of nanoparticles (e.g. size, polydispersity, loading capacity, zeta potential, morphology) are essential to system functions. Notably, these characteristics are regulated by fabrication variables, but in a complicated manner. This raises a great need to optimize fabrication process variables to ensure the desired nanoparticle characteristics. This paper presents a comprehensive experimental study on this matter, along with a novel method, the so-called Geno-Neural approach, to analyze, predict and optimize fabrication variables for desired nanoparticle characteristics. Specifically, ovalbumin was used as a protein model of growth factors used in cardiovascular tissue regeneration, and six fabrication variables were examined with regard to their influence on the characteristics of nanoparticles made from high molecular weight poly(lactide-co-glycolide). The six-factor five-level central composite rotatable design was applied to the conduction of experiments, and based on the experimental results, a geno-neural model was developed to determine the optimum fabrication conditions. For desired particle sizes of 150, 200, 250 and 300 nm, respectively, the optimum conditions to achieve the low polydispersity index, higher negative zeta potential and higher loading capacity were identified based on the developed geno-neural model and then evaluated experimentally. The experimental results revealed that the polymer and the external aqueous phase concentrations and their interactions with other fabrication variables were the most significant variables to affect the size, polydispersity index, zeta potential, loading capacity and initial burst release of the nanoparticles, while the electron microscopy images of the nanoparticles showed their spherical geometries with no sign of large pores or cracks on their surfaces. The release study revealed

  8. Colorimetric Detection of an Airborne Remote Photocatalytic Reaction Using a Stratified Ag Nanoparticle Sheet.

    PubMed

    Degawa, Ryo; Wang, Pangpang; Tanaka, Daisuke; Park, Susie; Sakai, Nobuyuki; Tatsuma, Tetsu; Okamoto, Koichi; Tamada, Kaoru

    2016-08-16

    Photocatalysts are practically used for decomposition of harmful and fouling organic compounds. Among the photocatalytic reactions, remote oxidation via airborne species is a relatively slow process, so that a sensitive technique for its detection has been awaiting. Here, we investigated an airborne remote photocatalytic reaction of a TiO2 photocatalyst modified with Pt nanoparticles as co-catalysts via the color change caused by a decomposition of a multilayered silver nanoparticle sheet. The silver nanoparticle sheet fabricated by the Langmuir-Schaefer method on a gold substrate exhibits a unique multicolor depending upon the number of layers. The color originates from multiple light trapping in the stratified sheets that has a metamaterial characteristic along with an intra- and interlayer coupling of localized surface plasmon resonance (LSPR). The stepwise decomposition of the sheets was confirmed by the colorimetric data, which exhibited not only a monotonic decrease but also a maximized absorption of light when the film thickness reached the optimal thickness for light trapping or when the oxidation of the Ag core started. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and surface plasmon resonance (SPR) spectroscopy data provided a complete view of the decomposition process of this inorganic-organic nanocomposite film, and simulation by the transfer-matrix method explained a simultaneous plasmonic response rationally. The influence of the humidity and gas flow rate on the airborne remote photocatalytic reaction kinetics was examined by this colorimetric detection method, and it suggests that H2O in air plays an essential role in the reaction. PMID:27445001

  9. Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES).

    PubMed

    Tsai, Candace S-J; Echevarría-Vega, Manuel E; Sotiriou, Georgios A; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

    2012-05-01

    Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO(2) ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20-46 % points compared to non-coated fabric and could provide collection efficiency above 95 %. PMID:23412707

  10. Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES)

    PubMed Central

    Echevarría-Vega, Manuel E.; Sotiriou, Georgios A.; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

    2013-01-01

    Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO2 ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20–46 % points compared to non-coated fabric and could provide collection efficiency above 95 %. PMID:23412707

  11. The Art of Engineering Viral Nanoparticles

    PubMed Central

    Pokorski, Jonathan K.; Steinmetz, Nicole F.

    2011-01-01

    Viral nanotechnology is an emerging and highly interdisciplinary field in which viral nanoparticles (VNPs) are applied in diverse areas such as electronics, energy and next-generation medical devices. VNPs have been developed as candidates for novel materials, and are often described as “programmable” because they can be modified and functionalized using a number of techniques. In this review, we discuss the concepts and methods that allow VNPs to be engineered, including (i) bioconjugation chemistries, (ii) encapsulation techniques, (iii) mineralization strategies, and (iv) film and hydrogel development. With all these techniques in hand, the potential applications of VNPs are limited only by the imagination. PMID:21047140

  12. Review of AIDS development. [airborne computers for reliability engineering

    NASA Technical Reports Server (NTRS)

    Vermeulen, H. C.; Danielsson, S. G.

    1981-01-01

    The operation and implementation of the aircraft integrated data system AIDS are described. The system is described as an engineering tool with strong emphasis on analysis of recorded information. The AIDS is primarily directed to the monitoring of parameters related to: the safety of the flight; the performance of the aircraft; the performance of the flight guidance system; and the performance and condition of the engines. The system provide short term trend analysis on a trend chart that is updated by the flight engineer on every flight that lasts more than 4 flight hours. Engine data prints are automatically presented during take-off and in the case of limit excedance, e.g., the print shows an automatically reported impending hotstarts on engine nr. 1. Other significant features are reported.

  13. *Evaluating the toxicity of airborne particulate matter and nanoparticles by measuring oxidative strett potential - A workshop report and consensus statement

    EPA Science Inventory

    BACKGROUND: There is a strong need for laboratory in vitro test systems for the toxicity of airborne particulate matter and nanoparticles. The measurement of oxidative stress potential offers a promising way forward. OBJECTIVES: A workshop was convened involving leading workers f...

  14. Airborne nanoparticle exposures while using constant-flow, constant-velocity, and air-curtain-isolated fume hoods.

    PubMed

    Tsai, Su-Jung Candace; Huang, Rong Fung; Ellenbecker, Michael J

    2010-01-01

    Tsai et al. (Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods. J Nanopart Res 2009; 11: 147-61) found that the handling of dry nanoalumina and nanosilver inside laboratory fume hoods can cause a significant release of airborne nanoparticles from the hood. Hood design affects the magnitude of release. With traditionally designed fume hoods, the airflow moves horizontally toward the hood cupboard; the turbulent airflow formed in the worker wake region interacts with the vortex in the constant-flow fume hood and this can cause nanoparticles to be carried out with the circulating airflow. Airborne particle concentrations were measured for three hood designs (constant-flow, constant-velocity, and air-curtain hoods) using manual handling of nanoalumina particles. The hood operator's airborne nanoparticle breathing zone exposure was measured over the size range from 5 nm to 20 mum. Experiments showed that the exposure magnitude for a constant-flow hood had high variability. The results for the constant-velocity hood varied by operating conditions, but were usually very low. The performance of the air-curtain hood, a new design with significantly different airflow pattern from traditional hoods, was consistent under all operating conditions and release was barely detected. Fog tests showed more intense turbulent airflow in traditional hoods and that the downward airflow from the double-layered sash to the suction slot of the air-curtain hood did not cause turbulence seen in other hoods. PMID:19933309

  15. Measurement Techniques for Respiratory Tract Deposition of Airborne Nanoparticles: A Critical Review

    PubMed Central

    Möller, Winfried; Pagels, Joakim H.; Kreyling, Wolfgang G.; Swietlicki, Erik; Schmid, Otmar

    2014-01-01

    Abstract Determination of the respiratory tract deposition of airborne particles is critical for risk assessment of air pollution, inhaled drug delivery, and understanding of respiratory disease. With the advent of nanotechnology, there has been an increasing interest in the measurement of pulmonary deposition of nanoparticles because of their unique properties in inhalation toxicology and medicine. Over the last century, around 50 studies have presented experimental data on lung deposition of nanoparticles (typical diameter≤100 nm, but here≤300 nm). These data show a considerable variability, partly due to differences in the applied methodologies. In this study, we review the experimental techniques for measuring respiratory tract deposition of nano-sized particles, analyze critical experimental design aspects causing measurement uncertainties, and suggest methodologies for future studies. It is shown that, although particle detection techniques have developed with time, the overall methodology in respiratory tract deposition experiments has not seen similar progress. Available experience from previous research has often not been incorporated, and some methodological design aspects that were overlooked in 30–70% of all studies may have biased the experimental data. This has contributed to a significant uncertainty on the absolute value of the lung deposition fraction of nanoparticles. We estimate the impact of the design aspects on obtained data, discuss solutions to minimize errors, and highlight gaps in the available experimental set of data. PMID:24151837

  16. Measurement techniques for respiratory tract deposition of airborne nanoparticles: a critical review.

    PubMed

    Löndahl, Jakob; Möller, Winfried; Pagels, Joakim H; Kreyling, Wolfgang G; Swietlicki, Erik; Schmid, Otmar

    2014-08-01

    Determination of the respiratory tract deposition of airborne particles is critical for risk assessment of air pollution, inhaled drug delivery, and understanding of respiratory disease. With the advent of nanotechnology, there has been an increasing interest in the measurement of pulmonary deposition of nanoparticles because of their unique properties in inhalation toxicology and medicine. Over the last century, around 50 studies have presented experimental data on lung deposition of nanoparticles (typical diameter≤100 nm, but here≤300 nm). These data show a considerable variability, partly due to differences in the applied methodologies. In this study, we review the experimental techniques for measuring respiratory tract deposition of nano-sized particles, analyze critical experimental design aspects causing measurement uncertainties, and suggest methodologies for future studies. It is shown that, although particle detection techniques have developed with time, the overall methodology in respiratory tract deposition experiments has not seen similar progress. Available experience from previous research has often not been incorporated, and some methodological design aspects that were overlooked in 30-70% of all studies may have biased the experimental data. This has contributed to a significant uncertainty on the absolute value of the lung deposition fraction of nanoparticles. We estimate the impact of the design aspects on obtained data, discuss solutions to minimize errors, and highlight gaps in the available experimental set of data. PMID:24151837

  17. Airborne remote sensors applied to engineering geology and civil works design investigations

    NASA Technical Reports Server (NTRS)

    Gelnett, R. H.

    1975-01-01

    The usefulness of various airborne remote sensing systems in the detection and identification of regional and specific geologic structural features that may affect the design and location of engineering structures on major civil works projects is evaluated. The Butler Valley Dam and Blue Lake Project in northern California was selected as a demonstration site. Findings derived from the interpretation of various kinds of imagery used are given.

  18. Optimization of an air-liquid interface exposure system for assessing toxicity of airborne nanoparticles.

    PubMed

    Latvala, Siiri; Hedberg, Jonas; Möller, Lennart; Odnevall Wallinder, Inger; Karlsson, Hanna L; Elihn, Karine

    2016-10-01

    The use of refined toxicological methods is currently needed for characterizing the risks of airborne nanoparticles (NPs) to human health. To mimic pulmonary exposure, we have developed an air-liquid interface (ALI) exposure system for direct deposition of airborne NPs on to lung cell cultures. Compared to traditional submerged systems, this allows more realistic exposure conditions for characterizing toxicological effects induced by airborne NPs. The purpose of this study was to investigate how the deposition of silver NPs (AgNPs) is affected by different conditions of the ALI system. Additionally, the viability and metabolic activity of A549 cells was studied following AgNP exposure. Particle deposition increased markedly with increasing aerosol flow rate and electrostatic field strength. The highest amount of deposited particles (2.2 μg cm(-2) ) at cell-free conditions following 2 h exposure was observed for the highest flow rate (390 ml min(-1) ) and the strongest electrostatic field (±2 kV). This was estimated corresponding to deposition efficiency of 94%. Cell viability was not affected after 2 h exposure to clean air in the ALI system. Cells exposed to AgNPs (0.45 and 0.74 μg cm(-2) ) showed significantly (P < 0.05) reduced metabolic activities (64 and 46%, respectively). Our study shows that the ALI exposure system can be used for generating conditions that were more realistic for in vitro exposures, which enables improved mechanistic and toxicological studies of NPs in contact with human lung cells.Copyright © 2016 The Authors Journal of Applied Toxicology Published by John Wiley & Sons Ltd. PMID:26935862

  19. Characterizing exposures to airborne metals and nanoparticle emissions in a refinery.

    PubMed

    Miller, Arthur; Drake, Pamela L; Hintz, Patrick; Habjan, Matt

    2010-07-01

    An air quality survey was conducted at a precious metals refinery in order to evaluate worker exposures to airborne metals and to provide detailed characterization of the aerosols. Two areas within the refinery were characterized: a furnace room and an electro-refining area. In line with standard survey practices, both personal and area air filter samples were collected on 37-mm filters and analyzed for metals by inductively coupled plasma-atomic emission spectroscopy. In addition to the standard sampling, measurements were conducted using other tools, designed to provide enhanced characterization of the workplace aerosols. The number concentration and number-weighted particle size distribution of airborne particles were measured with a fast mobility particle sizer (FMPS). Custom-designed software was used to correlate particle concentration data with spatial location data to generate contour maps of particle number concentrations in the work areas. Short-term samples were collected in areas of localized high concentrations and analyzed using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) to determine particle morphology and elemental chemistry. Analysis of filter samples indicated that all of the workers were exposed to levels of silver above the Occupational Safety and Health Administration permissible exposure limit of 0.01 mg m(-3) even though the localized ventilation was functioning. Measurements with the FMPS indicated that particle number concentrations near the furnace increased up to 1000-fold above the baseline during the pouring of molten metal. Spatial mapping revealed localized elevated particle concentrations near the furnaces and plumes of particles rising into the stairwells and traveling to the upper work areas. Results of TEM/EDS analyses confirmed the high number of nanoparticles measured by the FMPS and indicated the aerosols were rich in metals including silver, lead, antimony, selenium, and zinc. Results of

  20. Connecting NASA Airborne Scientists, Engineers, and Pilots to K-12 Classrooms

    NASA Astrophysics Data System (ADS)

    Schaller, E. L.

    2015-12-01

    The NASA Airborne Science Program (ASP) conducts Earth system science research missions with NASA aircraft all over the world. During ASP missions, NASA scientists, engineers and pilots are deployed to remote parts of the world such as Greenland, Antarctica, Chile, and Guam. These ASP mission personnel often have a strong desire to share the excitement of their mission with local classrooms near their deployment locations as well as classrooms back home in the United States. Here we discuss ongoing efforts to connect NASA scientists, engineers and pilots in the field directly with K-12 classrooms through both in-person interactions and remotely via live web-based chats.

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

    NASA Astrophysics Data System (ADS)

    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. Direct Patterning of Engineered Ionic Gold Nanoparticles via Nanoimprint Lithography

    SciTech Connect

    Yu, Xi; Pham, Jonathan; Subramani, Chandramouleeswaran; Creran, Brian; Yeh, Yi-Cheun; Du, Kan; Patra, Debabrata; Miranda, Oscar; Crosby, Alfred J.; Rotello, Vincent M.

    2012-10-01

    Gold nanoparticles are engineered for direct imprinting of stable structures. This imprinting strategy provides access to new device architectures, as demonstrated through the fabrication of a prototype photoswitchable device.

  3. Fate of Zinc and Silver Engineered Nanoparticles in Sewerage Networks

    EPA Science Inventory

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage sy...

  4. Acellular assessments of engineered-manufactured nanoparticle biological surface reactivity

    EPA Science Inventory

    It is critical to assess the surface properties and reactivity of engineered-manufactured nanoparticles (NPs) as these will influence their interactions with biological systems, biokinetics and toxicity. We examined the physicochemical properties and surface reactivity of metal o...

  5. Release, transport and toxicity of engineered nanoparticles.

    PubMed

    Soni, Deepika; Naoghare, Pravin K; Saravanadevi, Sivanesan; Pandey, Ram Avatar

    2015-01-01

    Recent developments in nanotechnology have facilitated the synthesis of novel engineered nanoparticles (ENPs) that possess new and different physicochemical properties. These ENPs have been ex tensive ly used in various commercial sectors to achieve both social and economic benefits. However. the increasing production and consumption of ENPs by many different industries has raised concerns about their possible release and accumulation in the environment. Released EN Ps may either remain suspended in the atmosphere for several years or may accumulate and eventually be modified int o other substances. Settled nanoparticles can he easily washed away during ra in s. and therefore may easily enter the food chain via water and so il. Thus. EN Ps can contaminate air. water and soil and can subsequently pose adverse risks to the health of different organisms. Studies to date indicate that ENP transport to and within the ecosystem depend on their chemical and physical properties (viz .. size. shape and solubility) . Therefore. the EN Ps display variable behavior in the environment because of their individual properties th at affect their tendency for adsorption, absorption, diffusional and colloidal interaction. The transport of EN Ps also influences their fate and chemical transformation in ecosystems. The adsorption, absorption and colloidal interaction of ENPs affect their capacity to be degraded or transformed, whereas the tendency of ENPs to agglomerate fosters their sedimentation. How widely ENPs are transported and their environmental fate influence how tox ic they may become to environmental organisms. One barrier to fully understanding how EN Ps are transformed in the environment and how best to characterize their toxicity, is related to the nature of their ultrafine structure. Experiments with different animals, pl ants, and cell lines have revealed that ENPs induce toxicity via several cellular pathways that is linked to the size. shape. surface area

  6. Source apportionment of airborne nanoparticles in a Middle Eastern city using positive matrix factorization.

    PubMed

    Al-Dabbous, Abdullah N; Kumar, Prashant

    2015-04-01

    Airborne nanoparticles have been studied worldwide, but little is known about their sources in the Middle East region, where hot, arid and dusty climatic conditions generally prevail. For the first time in Kuwait, we carried out size-resolved measurements of particle number distributions (PNDs) and concentrations (PNCs) in the 5-1000 nm size range. Measurements were made continuously for 31 days during the summer months of May and June 2013 using a fast-response differential mobility spectrometer (Cambustion DMS500) at a sampling rate of 10 Hz. Sources and their contributions were identified using the positive matrix factorization (PMF) approach that was applied to the PND data. Simultaneous measurements of gaseous pollutants (i.e., O3, NO, NOx, SO2 and CO), PM10, wind speed and direction were also carried out to aid the interpretation of the PMF results through the conditional probability function plots and Pearson product-moment correlations. Six major sources of PNCs were identified, contributing ∼46% (fresh traffic emissions), 27% (aged traffic emissions), 9% (industrial emissions), 9% (regional background), 6% (miscellaneous sources) and 3% (Arabian dust transport) of the total PNCs. The sources of nanoparticles and their PND profiles identified could serve as reference data to design more detailed field studies in the future and treat these sources in dispersion modelling and health impact assessment studies. PMID:25749465

  7. Granulometric characterization of airborne particulate release during spray application of nanoparticle-doped coatings.

    PubMed

    Göhler, Daniel; Stintz, Michael

    2014-01-01

    Airborne particle release during the spray application of coatings was analyzed in the nanometre and micrometre size range. In order to represent realistic conditions of domestic and handcraft use, the spray application was performed using two types of commercial propellant spray cans and a manual gravity spray gun. Four different types of coatings doped with three kinds of metal-oxide tracer nanoparticle additives (TNPA) were analyzed. Depending on the used coating and the kind of spray unit, particulate release numbers between 5 × 10(8) and 3 × 10(10) particles per gram ejection mass were determined in the dried spray aerosols. The nanoparticulate fraction amounted values between 10 and 60 no%. The comparison between nanoparticle-doped coatings with non-doped ones showed no TNPA-attributed differences in both the macroscopic spray process characteristics and the particle release numbers. SEM, TEM and EDX-analyzes showed that the spray aerosols were composed of particles made up solely from matrix material and sheathed pigments, fillers and TNPAs. Isolated ZnO- or Fe2O3-TNPAs could not be observed. PMID:25152690

  8. Engineering biofunctional magnetic nanoparticles for biotechnological applications

    NASA Astrophysics Data System (ADS)

    Moros, Maria; Pelaz, Beatriz; López-Larrubia, Pilar; García-Martin, Maria L.; Grazú, Valeria; de La Fuente, Jesus M.

    2010-09-01

    Synthesis and characterization of magnetic nanoparticles with excellent size control are showed here. Their functionalization using an amphiphilic polymer is also described. This strategy allows the stabilization of magnetic nanoparticles in aqueous solvents and in addition, the polymer shell serves as a platform to incorporate relevant biomolecules, such as poly(ethylene glycol) and a number of carbohydrates. Nanoparticles functionalized with carbohydrates show the ability to avoid unspecific interactions between proteins present in the working medium and the nanoparticles, so can be used as an alternative to poly(ethylene glycol) molecules. Results confirm these nanoparticles as excellent contrast agents for magnetic resonance imaging. Changes in the spin-spin transversal relaxation times of the surrounding water protons due to nanoparticle aggregation demonstrates the bioactivity of these nanoparticles functionalized with carbohydrates. To finish with, nanoparticle toxicity is evaluated by means of MTT assay. The obtained results clearly indicate that these nanoparticles are excellent candidates for their further application in nanomedicine or nanobiotechnology.Synthesis and characterization of magnetic nanoparticles with excellent size control are showed here. Their functionalization using an amphiphilic polymer is also described. This strategy allows the stabilization of magnetic nanoparticles in aqueous solvents and in addition, the polymer shell serves as a platform to incorporate relevant biomolecules, such as poly(ethylene glycol) and a number of carbohydrates. Nanoparticles functionalized with carbohydrates show the ability to avoid unspecific interactions between proteins present in the working medium and the nanoparticles, so can be used as an alternative to poly(ethylene glycol) molecules. Results confirm these nanoparticles as excellent contrast agents for magnetic resonance imaging. Changes in the spin-spin transversal relaxation times of the

  9. Airborne laser topographic mapping results from initial joint NASA/US Army Corps of Engineers experiment

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Collins, J. G.; Swift, R. N.; Butler, M. L.

    1980-01-01

    Initial results from a series of joint NASA/US Army Corps of Engineers experiments are presented. The NASA Airborne Oceanographic Lidar (AOL) was exercised over various terrain conditions, collecting both profile and scan data from which river basin cross sections are extracted. Comparisons of the laser data with both photogrammetry and ground surveys are made, with 12 to 27 cm agreement observed over open ground. Foliage penetration tests, utilizing the unique time-waveform sampling capability of the AOL, indicate 50 cm agreement with photogrammetry (known to have difficulty in foliage covered terrain).

  10. Nanoparticle engineering of colloidal suspension behavior

    NASA Astrophysics Data System (ADS)

    Chan, Angel Thanda

    We investigate the effects of highly charged nanoparticles on the phase behavior, structure, and assembly of colloidal microsphere suspensions. Specifically, by selectively tuning the electrostatic interactions between silica microspheres and polystyrene nanoparticles, we study the behavior of four key systems: (i) strongly repulsive, (ii) haloing, (iii) weakly attractive, and (iv) strongly attractive systems. In each system, a combination of nanoparticle adsorption, zeta potential, and confocal microscopy measurements are carried out to systematically study the effects of nanoparticle volume fraction, microsphere/nanoparticle size ratios, and interparticle interactions on their behavior. Our observations indicate that minimal adsorption of highly charged nanoparticles occurs on like-charged and negligibly-charged microspheres, whereas their extent of association increases dramatically with increasing microsphere-nanoparticle attraction. A rich phase behavior emerges in these systems based on whether the nanoparticle species serve as depletants, haloing, or bridging species. The phase transitions in the haloing system occur at constant nanoparticle volume fractions, φnano, over a broad range of microsphere volume fractions, φmicro . By contrast, the observed transitions in the weakly and strongly attractive mixtures occur at a constant number ratio of nanoparticles per microsphere, Nnano/Nmicro. Important structural differences emerge, which can be exploited in the assembly of colloidal gels for direct ink writing and colloidal crystals on epitaxially patterned substrates. Finally, for the first time, we explore nanoparticle haloing as a new route for stabilizing hydrophobic colloidal drugs in aqueous suspensions media for preparation of injectable pharmaceuticals. These microsphere suspensions exhibit improved stability relative to their surfactant-stabilized counterparts after autoclaving, a critical processing step for this target applications. This research

  11. Verification of engineering assumptions in modeling of airborne release of Carbon-14

    SciTech Connect

    Simonson, S.A.; Yim, Man-Sung

    1996-10-01

    The effects of atmospheric pressure variation on the flow velocity, water vapor transport, and oxygen depletion within a hypothetical low-level engineered waste facility were recently modeled with a set of engineering assumptions. The model that resulted from these activates is termed {open_quotes}GETAR{close_quote} for gas evolution, transport and reaction. Results of transport calculations show that the pumping effect of barometric pressure changes is the dominant mechanism for inducing the release of carbon-14 in a facility with a monitoring well. Coupled with this calculation, are recent results that indicate that a greater fraction of the carbon-14 within a hypothetical waste facility would be available for biodegradation and release via an airborne pathway rather than into groundwater.

  12. Engineering tailored nanoparticles with microbes: quo vadis?

    PubMed

    Prasad, Ram; Pandey, Rishikesh; Barman, Ishan

    2016-01-01

    In the quest for less toxic and cleaner methods of nanomaterials production, recent developments in the biosynthesis of nanoparticles have underscored the important role of microorganisms. Their intrinsic ability to withstand variable extremes of temperature, pressure, and pH coupled with the minimal downstream processing requirements provide an attractive route for diverse applications. Yet, controlling the dispersity and facile tuning of the morphology of the nanoparticles of desired chemical compositions remains an ongoing challenge. In this Focus Review, we critically review the advances in nanoparticle synthesis using microbes, ranging from bacteria and fungi to viruses, and discuss new insights into the cellular mechanisms of such formation that may, in the near future, allow complete control over particle morphology and functionalization. In addition to serving as paradigms for cost-effective, biocompatible, and eco-friendly synthesis, microbes hold the promise for a unique template for synthesis of tailored nanoparticles targeted at therapeutic and diagnostic platform technologies. PMID:26271947

  13. Engineered Silybin Nanoparticles Educe Efficient Control in Experimental Diabetes

    PubMed Central

    Das, Suvadra; Roy, Partha; Pal, Rajat; Auddy, Runa Ghosh; Chakraborti, Abhay Sankar; Mukherjee, Arup

    2014-01-01

    Silybin, is one imminent therapeutic for drug induced hepatotoxicity, human prostrate adenocarcinoma and other degenerative organ diseases. Recent evidences suggest that silybin influences gluconeogenesis pathways favorably and is beneficial in the treatment of type 1 and type 2 diabetes. The compound however is constrained due to solubility (0.4 mg/mL) and bioavailabilty limitations. Appropriate nanoparticle design for silybin in biocompatible polymers was thus proposed as a probable solution for therapeutic inadequacy. New surface engineered biopolymeric nanoparticles with high silybin encapsulation efficiency of 92.11% and zeta potential of +21 mV were designed. Both the pure compound and the nanoparticles were evaluated in vivo for the first time in experimental diabetic conditions. Animal health recovered substantially and the blood glucose levels came down to near normal values after 28 days treatment schedule with the engineered nanoparticles. Restoration from hyperglycemic damage condition was traced to serum insulin regeneration. Serum insulin recovered from the streptozotocin induced pancreatic damage levels of 0.17±0.01 µg/lit to 0.57±0.11 µg/lit after nanoparticle treatment. Significant reduction in glycated hemoglobin level, and restoration of liver glycogen content were some of the other interesting observations. Engineered silybin nanoparticle assisted recovery in diabetic conditions was reasoned due to improved silybin dissolution, passive transport in nanoscale, and restoration of antioxidant status. PMID:24991800

  14. Engineering nanoparticle-protein associations for protein crystal nucleation and nanoparticle arrangement

    NASA Astrophysics Data System (ADS)

    Benoit, Denise N.

    Engineering the nanoparticle - protein association offers a new way to form protein crystals as well as new approaches for arrangement of nanoparticles. Central to this control is the nanoparticle surface. By conjugating polymers on the surface with controlled molecular weights many properties of the nanoparticle can be changed including its size, stability in buffers and the association of proteins with its surface. Large molecular weight poly(ethylene glycol) (PEG) coatings allow for weak associations between proteins and nanoparticles. These interactions can lead to changes in how proteins crystallize. In particular, they decrease the time to nucleation and expand the range of conditions over which protein crystals form. Interestingly, when PEG chain lengths are too short then protein association is minimized and these effects are not observed. One important feature of protein crystals nucleated with nanoparticles is that the nanoparticles are incorporated into the crystals. What results are nanoparticles placed at well-defined distances in composite protein-nanoparticle crystals. Crystals on the size scale of 10 - 100 micrometers exhibit optical absorbance, fluorescence and super paramagnetic behavior derivative from the incorporated nanomaterials. The arrangement of nanoparticles into three dimensional arrays also gives rise to new and interesting physical and chemical properties, such as fluorescence enhancement and varied magnetic response. In addition, anisotropic nanomaterials aligned throughout the composite crystal have polarization dependent optical properties.

  15. Immunogenicity and ecotoxicity of engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Maurer-Jones, Melissa Ann

    The growing use of nanoscale materials in commercially available products and therapeutics has created an urgent need to determine the toxicity of these materials so that they may be designed and employed safely. As nanoparticles have unique physical and chemical properties, the challenges in determining their physiological and environmental impact have been numerous. It is, therefore, the goal of my thesis work to employ sensitive analytical tools to fundamentally understand the how nanoparticles interact with immunologically and ecologically relevant models. My project approaches nanotoxicity studies starting with a relevant model system exposed to well-characterized nanoparticles to (1) determine if cells/organisms survive exposure using traditional toxicological assays and, if the majority survives exposure, (2) use sensitive analytical tools to determine if there are changes to critical cell/organism function. If perturbation of function is detected, (3) the mechanism or cause of changes in cell function should be determined, including assessment of nanoparticle uptake and localization. Once a mechanism of interaction is determined, this process could begin again with a modified particle that may address the toxic response. Chapter Two describes the impact of metal oxide (TiO2 and SiO2) nanoparticles on mast cells, critical immune system cells, and utilizes the sensitive technique of carbon-fiber microelectrode amperometry (CFMA) to monitor changes in the important mast cell function of exocytosis. Chapter Three expands upon Chapter Two and examines in more detail the mechanism by which TiO2 nanoparticles impact exocytotic cell function, completing the process nanotoxicity described above. From these studies, it was determined that, while nanoparticles do not decrease the viability of mast cells, there are significant changes to exocytosis upon nanoparticle exposure, and in the case of TiO2, these changes in exocytosis are correlated to nanoparticle

  16. Potential for exposure to engineered nanoparticles from nanotechnology-based consumer spray products

    PubMed Central

    NAZARENKO, YEVGEN; HAN, TAE WON; LIOY, PAUL J.; MAINELIS, GEDIMINAS

    2014-01-01

    The potential for human exposure to engineered nanoparticles due to the use of nanotechnology-based consumer sprays (categorized as such by the Nanotechnology Consumer Products Inventory) is examined along with analogous products, which are not specified as nanotechnology-based (regular products). Photon correlation spectroscopy was used to obtain particle size distributions in the initial liquid products. Transmission electron microscopy was used to determine particle size, shape, and agglomeration of the particles. Realistic application of the spray products near the human breathing zone characterized airborne particles that are released during use of the sprays. Aerosolization of sprays with standard nebulizers was used to determine their potential for inhalation exposure. Electron microscopy detected the presence of nanoparticles in some nanotechnology-based sprays as well as in several regular products, whereas the photon correlation spectroscopy indicated the presence of particles <100 nm in all investigated products. During the use of most nanotechnology-based and regular sprays, particles ranging from 13 nm to 20 μm were released, indicating that they could he inhaled and consequently deposited in all regions of the respiratory system. The results indicate that exposures to nanoparticles as well as micrometer-sized particles can be encountered owing to the use of nanotechnology-based sprays as well as regular spray products. PMID:21364702

  17. Remediation of lindane using engineered nanoparticles.

    PubMed

    Srivastava, Mugdha; Abhilash, P C; Singh, Nandita

    2011-02-01

    Organochlorine pesticides (OCPs; aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, toxaphene and hexachlorocyclohexane) are chemical pollutants found in all environmental media. There is an urgent need to stop the usage and develop innovative strategies for the remediation of contaminated soil and water. The present work was aimed to evaluate the (i) interaction of fullerene with lindane and its role in the remediation of lindane from contaminated systems and (ii) compare the interaction of fullerene with lindane and trichloroethylene. Strong molecule-surface bonding of fullerene-lindane complex than fullerene-TCE complex indicates that fullerene can be used as a potential nanoparticle for remediation of lindane. However, toxicity and fate of nanoparticles is under investigation and more studies are needed before utilization of fullerene and other nanoparticles for phytoremediation. PMID:21485857

  18. Rationally engineered polymeric cisplatin nanoparticles for improved antitumor efficacy

    NASA Astrophysics Data System (ADS)

    Paraskar, Abhimanyu; Soni, Shivani; Basu, Sudipta; Amarasiriwardena, Chitra J.; Lupoli, Nicola; Srivats, Shyam; Sinha Roy, Rituparna; Sengupta, Shiladitya

    2011-07-01

    The use of cisplatin, a first line chemotherapy for most cancers, is dose-limited due to nephrotoxicity. While this toxicity can be addressed through nanotechnology, previous attempts at engineering cisplatin nanoparticles have been limited by the impact on the potency of cisplatin. Here we report the rational engineering of a novel cisplatin nanoparticle by harnessing a novel polyethylene glycol-functionalized poly-isobutylene-maleic acid (PEG-PIMA) copolymer, which can complex with cis-platinum (II) through a monocarboxylato and a coordinate bond. We show that this complex self-assembles into a nanoparticle, and exhibits an IC50 = 0.77 ± 0.11 µM comparable to that of free cisplatin (IC50 = 0.44 ± 0.09 µM). The nanoparticles are internalized into the endolysosomal compartment of cancer cells, and release cisplatin in a pH-dependent manner. Furthermore, the nanoparticles exhibit significantly improved antitumor efficacy in a 4T1 breast cancer model in vivo, with limited nephrotoxicity, which can be explained by preferential biodistribution in the tumor with reduced kidney concentrations. Our results suggest that the PEG-PIMA-cisplatin nanoparticle can emerge as an attractive solution to the challenges in cisplatin chemotherapy.

  19. Airborne nanoparticles (PM0.1 ) induce autophagic cell death of human neuronal cells.

    PubMed

    Jeon, Yu-Mi; Lee, Mi-Young

    2016-10-01

    Airborne nanoparticles PM0.1 (<100 nm in diameter) were collected and their chemical composition was determined. Al was by far the most abundant metal in the PM0.1 followed by Zn, Cr, Mn, Cu, Pb and Ni. Exposure to PM0.1 resulted in a cell viability decrease in human neuronal cells SH-SY5Y in a concentration-dependent manner. Upon treatment with N-acetylcysteine, however, cell viability was significantly recovered, suggesting the involvement of reactive oxygen species (ROS). Cellular DNA damage by PM0.1 was also detected by the Comet assay. PM0.1 -induced autophagic cell death was explained by an increase in the expression of microtubule-associated protein light chain 3A-ІІ (LC3A-ІІ) and autophagy-related protein Atg 3 and Atg 7. Analysis of 2-DE gels revealed that six proteins were upregulated, whereas eight proteins were downregulated by PM0.1 exposure. Neuroinflammation-related lithostathine and cyclophilin A complexed with dipeptide Gly-Pro, autophagy-related heat shock protein gp96 and neurodegeneration-related triosephosphate isomerase were significantly changed upon exposure to PM0.1 . These results, taken together, suggest that PM0.1 -induced oxidative stress via ROS generation plays a key role in autophagic cell death and differential protein expressions in SH-SY5Y cells. This might provide a plausible explanation for the underlying mechanisms of PM0.1 toxicity in neuronal cells and even the pathogenesis of diseases associated with its exposure. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27080386

  20. Shape Engineered Nanoparticle Fabrication for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Nasrullah, Azeem

    Semiconductor fabrication research has developed technologies that allow for the deposition and patterning of thin films, and can be applied to many different industries, including the field of medicine. One such application is the fabrication of nanoparticles. There is a wide variety of nanoparticle-based medical diagnostics and therapies, including drug delivery and cancer imaging. Most of the nanoparticles being studied are chemically synthesized and spherical in shape, and studies have shown that other shapes can be more useful in certain applications, especially those that involve in vivo analysis and treatment. Fabrication of particles using a tool set developed from the semiconductor industry can allow for a detailed study of size and shape dependence on nanoparticle uptake in the bloodstream. Particle fabrication is achieved using thin film deposition, ion beam proximity lithography, wet etching, and lift-off, all similar to techniques commonly found in the semiconductor industry. The particles are formed using patterns developed with proximity lithography, and this represents the largest effort in this work. An ion beam, generated by a saddle-field ion source, is used to irradiate a polymeric resist with a thin membrane stencil mask placed in close proximity to the resist coated substrate in order to define the pattern. A saddle-field ion source was constructed and characterized for proximity lithography, with a beam diameter of 4.8 mm for a +/-5% tolerance in current density, a source size range of 0.3--0.9 mm, an average brightness value of 15 nAcm2˙sr , and average exposure times of ≈30 s. Stencil masks were fabricated from silicon nitride membranes in order to generate the pattern for the nanoparticles, and the particles were fabricated using a bi-layer resist and a sacrificial copper layer for release into solution.

  1. Engineered nanoparticles: Revisiting safety concerns in light of ethno medicine

    PubMed Central

    Palkhiwala, Suhani; Bakshi, Sonal R.

    2014-01-01

    The nanoparticles are a miracle invention of the century that has opened novel avenues of applications in various fields. The safety aspect of exposure to nanoparticles for humans, plants, animals, soil micro-flora, and ecosystem at large has been questioned. The safety concern can be addressed by laboratory studies to assess the actual risk and recommend exposure limits and related regulation. There is also a suggestion for considering the nanoparticle form of conventional compounds as a new chemical and subject it to safety assessment in line with the chemical regulatory agencies. In the light of the current scenario of popularity and safety concerns regarding nanoparticles, the use of ancient metal based forms like, Bhasma is revisited in the present article. The current approach of green synthesis of nanoparticles is compared with the Ayurveda Rasayana Shastra guidelines of Bhasma preparation and modern preparation of engineered nanoparticles. Since the benefits of nanotechnology are undeniable, and safety concerns are also not ungrounded, there is a pressing need to revisit the ways nanoparticles are manufactured, and to carry out safety assessment by the techniques specially adapted for this novel compound. PMID:26664232

  2. Fate of Engineered Nanoparticles: Implications in the Environment

    EPA Science Inventory

    The increased flux of the engineered nanoparticles (ENPs) in consumer and commercial products has become a viable threat, particularly if their release affects the environment. The aim of this paper is to review the recent literature results pertaining to the underlying mechanism...

  3. Occupational exposure to airborne nanomaterials: An assessment of worker exposure to aerosolized metal oxide nanoparticles in a semiconductor fab and subfab.

    PubMed

    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

  4. Engineering spatial gradients of signaling proteins using magnetic nanoparticles.

    PubMed

    Bonnemay, L; Hostachy, S; Hoffmann, C; Gautier, J; Gueroui, Z

    2013-11-13

    Intracellular biochemical reactions are often localized in space and time, inducing gradients of enzymatic activity that may play decisive roles in determining cell's fate and functions. However, the techniques available to examine such enzymatic gradients of activity remain limited. Here, we propose a new method to engineer a spatial gradient of signaling protein concentration within Xenopus egg extracts using superparamagnetic nanoparticles. We show that, upon the application of a magnetic field, a concentration gradient of nanoparticles with a tunable length extension is established within confined egg extracts. We then conjugate the nanoparticles to RanGTP, a small G-protein controlling microtubule assembly. We found that the generation of an artificial gradient of Ran-nanoparticles modifies the spatial positioning of microtubule assemblies. Furthermore, the spatial control of the level of Ran concentration allows us to correlate the local fold increase in Ran-nanoparticle concentration with the spatial positioning of the microtubule-asters. Our assay provides a bottom-up approach to examine the minimum ingredients generating polarization and symmetry breaking within cells. More generally, these results show how magnetic nanoparticles and magnetogenetic tools can be used to control the spatiotemporal dynamics of signaling pathways. PMID:24111679

  5. Engineered inorganic nanoparticles for drug delivery applications.

    PubMed

    Ojea-Jiménez, Isaac; Comenge, Joan; García-Fernández, Lorena; Megson, Zoë A; Casals, Eudald; Puntes, Victor F

    2013-06-01

    Inorganic nanoparticles (NPs) currently have immense potential as drug delivery vectors due to their unique physicochemical properties such as high surface area per unit volume, their optical and magnetic uniqueness and the ability to be functionalized with a large number of ligands to enhance their affinity towards target molecules. These features, together with the therapeutic activity of some drugs, render the combination of these two entities (NP-drug) as an attractive alternative in the area of drug delivery. One of the major advantages of these conjugates is the possibility to have a local delivery of the drug, thus reducing systemic side effects and enabling a higher efficiency of the therapeutic molecule. This review highlights the direct implications of nanoscale particles in the development of drug delivery systems. In more detail, it is also remarked the extensive use of inorganic NPs for targeted cancer therapies. As the range of nanoparticles and their applications continues to increase, human safety concerns are gaining importance, which makes it necessary to better understand the potential toxicity hazards of these materials. PMID:23116108

  6. Lattice engineering through nanoparticle-DNA frameworks.

    PubMed

    Tian, Ye; Zhang, Yugang; Wang, Tong; Xin, Huolin L; Li, Huilin; Gang, Oleg

    2016-06-01

    Advances in self-assembly over the past decade have demonstrated that nano- and microscale particles can be organized into a large diversity of ordered three-dimensional (3D) lattices. However, the ability to generate different desired lattice types from the same set of particles remains challenging. Here, we show that nanoparticles can be assembled into crystalline and open 3D frameworks by connecting them through designed DNA-based polyhedral frames. The geometrical shapes of the frames, combined with the DNA-assisted binding properties of their vertices, facilitate the well-defined topological connections between particles in accordance with frame geometry. With this strategy, different crystallographic lattices using the same particles can be assembled by introduction of the corresponding DNA polyhedral frames. This approach should facilitate the rational assembly of nanoscale lattices through the design of the unit cell. PMID:26901516

  7. Ligand engineering of nanoparticle solar cells

    NASA Astrophysics Data System (ADS)

    Voros, Marton

    Semiconductor nanoparticles (NP) are promising materials to build cheap and efficient solar cells. One of the key challenges in their utilization for solar energy conversion is the control of NP surfaces and ligand-NP interfaces. Recent experiments have shown that by carefully choosing the ligands terminating the NPs, one can tailor electronic and optical absorption properties of NP assemblies, along with their transport properties. By using density functional theory based methods, we investigated how the opto-electronic properties of lead chalcogenide NPs may be tuned by using diverse organic and inorganic ligands. We interpreted experiments, and we showed that an essential prerequisite to avoid detrimental trap states is to ensure charge balance at the ligand-NP interface, possibly with the help of hydrogen treatment Work supported by the Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

  8. Lattice engineering through nanoparticle-DNA frameworks

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Zhang, Yugang; Wang, Tong; Xin, Huolin L.; Li, Huilin; Gang, Oleg

    2016-06-01

    Advances in self-assembly over the past decade have demonstrated that nano- and microscale particles can be organized into a large diversity of ordered three-dimensional (3D) lattices. However, the ability to generate different desired lattice types from the same set of particles remains challenging. Here, we show that nanoparticles can be assembled into crystalline and open 3D frameworks by connecting them through designed DNA-based polyhedral frames. The geometrical shapes of the frames, combined with the DNA-assisted binding properties of their vertices, facilitate the well-defined topological connections between particles in accordance with frame geometry. With this strategy, different crystallographic lattices using the same particles can be assembled by introduction of the corresponding DNA polyhedral frames. This approach should facilitate the rational assembly of nanoscale lattices through the design of the unit cell.

  9. Cellular interactions with tissue-engineered microenvironments and nanoparticles

    NASA Astrophysics Data System (ADS)

    Pan, Zhi

    Tissue-engineered hydrogels composed of intermolecularlly crosslinked hyaluronan (HA-DTPH) and fibronectin functional domains (FNfds) were applied as a physiological relevant ECM mimic with controlled mechanical and biochemical properties. Cellular interactions with this tissue-engineered environment, especially physical interactions (cellular traction forces), were quantitatively measured by using the digital image speckle correlation (DISC) technique and finite element method (FEM). By correlating with other cell functions such as cell morphology and migration, a comprehensive structure-function relationship between cells and their environments was identified. Furthermore, spatiotemporal redistribution of cellular traction stresses was time-lapse measured during cell migration to better understand the dynamics of cell mobility. The results suggest that the reinforcement of the traction stresses around the nucleus, as well as the relaxation of nuclear deformation, are critical steps during cell migration, serving as a speed regulator, which must be considered in any dynamic molecular reconstruction model of tissue cell migration. Besides single cell migration, en masse cell migration was studied by using agarose droplet migration assay. Cell density was demonstrated to be another important parameter to influence cell behaviors besides substrate properties. Findings from these studies will provide fundamental design criteria to develop novel and effective tissue-engineered constructs. Cellular interactions with rutile and anatase TiO2 nanoparticles were also studied. These particles can penetrate easily through the cell membrane and impair cell function, with the latter being more damaging. The exposure to nanoparticles was found to decrease cell area, cell proliferation, motility, and contractility. To prevent this, a dense grafted polymer brush coating was applied onto the nanoparticle surface. These modified nanoparticles failed to adhere to and penetrate

  10. Engineered Hybrid Nanoparticles for On-Demand Diagnostics and Therapeutics.

    PubMed

    Nguyen, Kim Truc; Zhao, Yanli

    2015-12-15

    Together with the simultaneous development of nanomaterials and molecular biology, the bionano interface brings about various applications of hybrid nanoparticles in nanomedicine. The hybrid nanoparticles not only present properties of the individual components but also show synergistic effects for specialized applications. Thus, the development of advanced hybrid nanoparticles for targeted and on-demand diagnostics and therapeutics of diseases has rapidly become a hot research topic in nanomedicine. The research focus is to fabricate novel classes of programmable hybrid nanoparticles that are precisely engineered to maximize drug concentrations in diseased cells, leading to enhanced efficacy and reduced side effects of chemotherapy for the disease treatment. In particular, the hybrid nanoparticle platforms can simultaneously target diseased cells, enable the location to be imaged by optical methods, and release therapeutic drugs to the diseased cells by command. This Account specially discusses the rational fabrication of integrated hybrid nanoparticles and their applications in diagnostics and therapeutics. For diagnostics applications, hybrid nanoparticles can be utilized as imaging agents that enable detailed visualization at the molecular level. By the use of suitable targeting ligands incorporated on the nanoparticles, targeted optical imaging may be feasible with improved performance. Novel imaging techniques such as multiphoton excitation and photoacoustic imaging using near-infrared light have been developed using the intrinsic properties of particular nanoparticles. The use of longer-wavelength excitation sources allows deeper penetration into the human body for disease diagnostics and at the same time reduces the adverse effects on normal tissues. Furthermore, multimodal imaging techniques have been achieved by combining several types of components in nanoparticles, offering higher accuracy and better spatial views, with the aim of detecting life

  11. Exposure modeling of engineered nanoparticles in the environment.

    PubMed

    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 (< 1 microg/L). The risk quotients (PEC/PNEC) for CNT and 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

  12. Engineered nanoparticles interacting with cells: size matters

    PubMed Central

    2014-01-01

    With the rapid advancement of nanoscience and nanotechnology, detailed knowledge of interactions between engineered nanomaterials and cells, tissues and organisms has become increasingly important, especially in regard to possible hazards to human health. This review intends to give an overview of current research on nano-bio interactions, with a focus on the effects of NP size on their interactions with live cells. We summarize common techniques to characterize NP size, highlight recent work on the impact of NP size on active and passive cellular internalization and intracellular localization. Cytotoxic effects are also discussed. PMID:24491160

  13. Engineered metal based nanoparticles and innate immunity.

    PubMed

    Petrarca, Claudia; Clemente, Emanuela; Amato, Valentina; Pedata, Paola; Sabbioni, Enrico; Bernardini, Giovanni; Iavicoli, Ivo; Cortese, Sara; Niu, Qiao; Otsuki, Takemi; Paganelli, Roberto; Di Gioacchino, Mario

    2015-01-01

    Almost all people in developed countries are exposed to metal nanoparticles (MeNPs) that are used in a large number of applications including medical (for diagnostic and therapeutic purposes). Once inside the body, absorbed by inhalation, contact, ingestion and injection, MeNPs can translocate to tissues and, as any foreign substance, are likely to encounter the innate immunity system that represent a non-specific first line of defense against potential threats to the host. In this review, we will discuss the possible effects of MeNPs on various components of the innate immunity (both specific cells and barriers). Most important is that there are no reports of immune diseases induced by MeNPs exposure: we are operating in a safe area. However, in vitro assays show that MeNPs have some effects on innate immunity, the main being toxicity (both cyto- and genotoxicity) and interference with the activity of various cells through modification of membrane receptors, gene expression and cytokine production. Such effects can have both negative and positive relevant impacts on humans. On the one hand, people exposed to high levels of MeNPs, as workers of industries producing or applying MeNPs, should be monitored for possible health effects. On the other hand, understanding the modality of the effects on immune responses is essential to develop medical applications for MeNPs. Indeed, those MeNPs that are able to stimulate immune cells could be used to develop of new vaccines, promote immunity against tumors and suppress autoimmunity. PMID:26180517

  14. Engineered cerium oxide nanoparticles: Effects on bacterial growth and viability

    SciTech Connect

    Pelletier, Dale A; Suresh, Anil K; Holton, Gregory A; McKeown, Catherine K; Wang, Wei; Gu, Baohua; Mortensen, Ninell P; Allison, David P; Joy, David Charles; Allison, Martin R; Brown, Steven D; Phelps, Tommy Joe; Doktycz, Mitchel John

    2010-01-01

    Interest in engineered nanostructures has risen in recent years due to their use in energy conservation strategies and biomedicine. To ensure prudent development and use of nanomaterials, the fate and effects of such engineered structures on the environment should be understood. Interactions of nanomaterials with environmental microorganisms are inevitable, but the general consequences of such interactions remain unclear. Further, standardized methods for assessing such interactions are lacking. Therefore, we have initiated a multianalytical approach to understand the interactions of synthesized nanoparticles with bacterial systems. These efforts are focused initially on cerium oxide nanoparticles and model bacteria in order to evaluate characterization procedures and the possible fate of such materials in the environment. In this study the effects of cerium oxide nanoparticles on the growth and viability of Gram-negative Escherichia coli and Shewanella oneidensis, a metal-reducing bacteria, and Gram-positive Bacillus subtilis were examined relative to particle size, growth media, pH, and dosage. A hydrothermal based synthesis procedure was used to prepare cerium oxide nanoparticles of defined sizes in order to eliminate complications originating from the use of organic solvents and surfactants. Bactericidal effects were determined by minimum inhibitory concentration, colony forming units, disc diffusion tests and Live/Dead assays. In growth inhibition experiments involving E. coli and B. subtilis, a clear strain and size-dependent inhibition was observed. S. oneidensis appeared to be unaffected by the cerium oxide nanoparticles. Transmission electron microscopy along with microarray-based transcriptional profiling have been used to understand the response mechanism of the bacteria. The use of multiple analytical approaches adds confidence to toxicity assessments while the use of different bacterial systems highlights the potential wide-ranging effects of

  15. A chemical free, nanotechnology-based method for airborne bacterial inactivation using engineered water nanostructures†‡

    PubMed Central

    Pyrgiotakis, Georgios; McDevitt, James; Bordini, Andre; Diaz, Edgar; Molina, Ramon; Watson, Christa; Deloid, Glen; Lenard, Steve; Fix, Natalie; Mizuyama, Yosuke; Yamauchi, Toshiyuki; Brain, Joseph

    2015-01-01

    Airborne pathogens are associated with the spread of infectious diseases and increased morbidity and mortality. Herein we present an emerging chemical free, nanotechnology-based method for airborne pathogen inactivation. This technique is based on transforming atmospheric water vapor into Engineered Water Nano-Structures (EWNS) via electrospray. The generated EWNS possess a unique set of physical, chemical, morphological and biological properties. Their average size is 25 nm and they contain reactive oxygen species (ROS) such as hydroxyl and superoxide radicals. In addition, EWNS are highly electrically charged (10 electrons per particle on average). A link between their electric charge and the reduction of their evaporation rate was illustrated resulting in an extended lifetime (over an hour) at room conditions. Furthermore, it was clearly demonstrated that the EWNS have the ability to interact with and inactivate airborne bacteria. Finally, inhaled EWNS were found to have minimal toxicological effects, as illustrated in an acute in-vivo inhalation study using a mouse model. In conclusion, this novel, chemical free, nanotechnology-based method has the potential to be used in the battle against airborne infectious diseases. PMID:26180637

  16. Inkjet-printed silver nanoparticle paper detects airborne species from crystalline explosives and their ultratrace residues in open environment.

    PubMed

    Wang, Jianping; Yang, Liang; Liu, Bianhua; Jiang, Haihe; Liu, Renyong; Yang, Jingwei; Han, Guangmei; Mei, Qingsong; Zhang, Zhongping

    2014-04-01

    An electronic nose can detect highly volatile chemicals in foods, drugs, and environments, but it is still very much a challenge to detect the odors from crystalline compounds (e.g., solid explosives) with a low vapor pressure using the present chemosensing techniques in such way as a dog's olfactory system can do. Here, we inkjet printed silver nanoparticles (AgNPs) on cellulose paper and established a Raman spectroscopic approach to detect the odors of explosive trinitrotoluene (TNT) crystals and residues in the open environment. The layer-by-layer printed AgNP paper was modified with p-aminobenzenethiol (PABT) for efficiently collecting airborne TNT via a charge-transfer reaction and for greatly enhancing the Raman scattering of PABT by multiple spectral resonances. Thus, a Raman switch concept by the Raman readout of PABT for the detection of TNT was proposed. The AgNPs paper at different sites exhibited a highly uniform sensitivity to TNT due to the layer-by-layer printing, and the sensitive limit could reach 1.6 × 10(-17) g/cm(2) TNT. Experimentally, upon applying a beam of near-infrared low-energy laser to slightly heat (but not destruct) TNT crystals, the resulting airborne TNT in the open environment was probed at the height of 5 cm, in which the concentration of airborne species was lower than 10 ppt by a theoretical analysis. Similarly, the odors from 1.4 ppm TNT in soil and 7.2, 2.9, and 5.7 ng/cm(2) TNT on clothing, leather, and envelope, respectively, were also quickly sensed for 2 s without destoying these inspected objects. PMID:24605843

  17. Viscosity of alumina nanoparticles dispersed in car engine coolant

    SciTech Connect

    Kole, Madhusree; Dey, T.K.

    2010-09-15

    The present paper, describes our experimental results on the viscosity of the nanofluid prepared by dispersing alumina nanoparticles (<50 nm) in commercial car coolant. The nanofluid prepared with calculated amount of oleic acid (surfactant) was tested to be stable for more than 80 days. The viscosity of the nanofluids is measured both as a function of alumina volume fraction and temperature between 10 and 50 C. While the pure base fluid display Newtonian behavior over the measured temperature, it transforms to a non-Newtonian fluid with addition of a small amount of alumina nanoparticles. Our results show that viscosity of the nanofluid increases with increasing nanoparticle concentration and decreases with increase in temperature. Most of the frequently used classical models severely under predict the measured viscosity. Volume fraction dependence of the nanofluid viscosity, however, is predicted fairly well on the basis of a recently reported theoretical model for nanofluids that takes into account the effect of Brownian motion of nanoparticles in the nanofluid. The temperature dependence of the viscosity of engine coolant based alumina nanofluids obeys the empirical correlation of the type: log ({mu}{sub nf}) = A exp(BT), proposed earlier by Namburu et al. (author)

  18. Engineering Silver Nanoparticles: Towards a Tunable Antimicrobial

    NASA Astrophysics Data System (ADS)

    Puppala, Hema Lakshmi

    Overwhelming production of commercially available products containing silver nanoparticles (AgNPs) underscores the studies determining their fate in the environment. In order to regulate the use, assess the environmental impact and develop eco-responsible silver products, models that can predict AgNP toxicity based on physicochemical properties are vital. With that vision, this thesis developed well-characterized model libraries of uniform AgNPs stabilized with oleate in the range of 2-45 nm diameter with variable surface coating and investigated the dissolution properties that link AgNP structure to antimicrobial activity. High temperature organic synthesis allowed controlled growth of AgNPs (sigma<15%) by an Ostwald ripening mechanism in the first few hours, and followed by size dependent growth rates yielding uniform nanocrystals. Characterization of these materials revealed a crystalline nature, bidentate binding mode of oleate and non-oxidized pristine silver surface. Phase transfer of these AgNPs from organics to water was facilitated by encapsulation and ligand exchange methods using amphiphilic polymers and methoxy poly (ethylene glycol) (mPEGSH) respectively. Among these surface coatings, steric stabilization by mPEGSH not only helped retain their optical properties but also reduced the dissolution (<1(w/w)%) of AgNPs. This enhanced the stability in various environmentally relevant high ionic strength media (such as Hoaglands, EPA hard water and OECD medium), thereby increasing the shelf life. In addition, size, surface coating, pH of the medium and grafting density of the polymer mediated the dissolution of AgNPs. For instance, the rate of dissolution was decreased by 40% when the polymer coating possessed a mushroom conformation and increased with reducing core size. Analogous to dissolution, physicochemical properties also influenced the antimicrobial activity which were studied by minimum inhibitory concentration (MIC) and bactericidal efficacy assays

  19. Transport of stabilized engineered silver (Ag) nanoparticles through porous sandstones

    NASA Astrophysics Data System (ADS)

    Neukum, Christoph; Braun, Anika; Azzam, Rafig

    2014-03-01

    Engineered nanoparticles are increasingly applied in consumer products and concerns are rising regarding their risk as potential contaminants or carriers for colloid-facilitated contaminant transport. Engineered silver nanoparticles (AgNP) are among the most widely used nanomaterials in consumer products. However, their mobility in groundwater has been scarcely investigated. In this study, transport of stabilized AgNP through porous sandstones with variations in mineralogy, pore size distribution and permeability is investigated in laboratory experiments with well-defined boundary conditions. The AgNP samples were mainly characterized by asymmetric flow field-flow fractionation coupled to a multi-angle static laser light detector and ultraviolet-visible spectroscopy for determination of particle size and concentration. The rock samples are characterized by mercury porosimetry, flow experiments and solute tracer tests. Solute and AgNP breakthrough was quantified by applying numerical models considering one kinetic site model for particle transport. The transport of AgNP strongly depends on pore size distribution, mineralogy and the solution ionic strength. Blocking of attachment sites results in less reactive transport with increasing application of AgNP mass. AgNPs were retained due to physicochemical filtration and probably due to straining. The results demonstrate the restricted applicability of AgNP transport parameters determined from simplified experimental model systems to realistic environmental matrices.

  20. An occupational exposure assessment for engineered nanoparticles used in semiconductor fabrication.

    PubMed

    Shepard, Michele Noble; Brenner, Sara

    2014-03-01

    Engineered nanoparticles of alumina, amorphous silica, and ceria are used in semiconductor device fabrication during wafer polishing steps referred to as 'chemical mechanical planarization' (CMP). Some metal oxide nanoparticles can impact the biological response of cells and organ systems and may cause adverse health effects; additional research is necessary to better understand potential risks from nanomaterial applications and occupational exposure scenarios. This study was conducted to assess potential airborne exposures to nanoparticles and agglomerates using direct-reading instruments and filter-based samples to characterize workplace aerosols by particle number, mass, size, composition, and morphology. Sampling was repeated for tasks in three work areas (fab, subfab, wastewater treatment) at a facility using engineered nanoparticles for CMP. Real-time measurements were collected using a condensation particle counter (CPC), optical particle counter, and scanning mobility particle spectrometer (SMPS). Filter-based samples were analyzed for total mass or the respirable fraction, and for specific metals of interest. Additional air sample filters were analyzed by transmission electron microscopy with energy dispersive x-ray spectroscopy (TEM/EDX) for elemental identification and to provide data on particle size, morphology, and concentration. Peak concentrations measured on the CPC ranged from 1 to 16 particles per cubic centimeter (P cm(-3)) for background and from 4 to 74 P cm(-3) during tasks sampled in the fab; from 1 to 60 P cm(-3) for background and from 3 to 84 P cm(-3) for tasks sampled in the subfab; and from 1160 to 45 894 P cm(-3) for background and from 1710 to 45 519 P cm(-3) during wastewater treatment system filter change tasks. Significant variability was seen among the repeated task measurements and among background comparisons in each area. Several data analysis methods were used to compare each set of task and background measurements. Increased

  1. The fate of airborne nanoparticles released from a leak in a nanoparticle production process into a simulated workplace environment

    NASA Astrophysics Data System (ADS)

    Stanley, Nicholas James

    A leak in nanoparticle production equipment can cause large quantities of nanoparticles to be emitted into a workplace environment. Toxicity studies have shown hazards of inhaling nanoparticles; however these studies may not be using the proper particles. Physical and chemical changes may occur as these nanoparticles travel from the production site through ambient air, causing worker exposure. With the correct size and concentration known at distances from the leak, realistic worker exposure can be determined and appropriate worker protection and occupational monitoring schemes can be developed. Different nanoparticle materials were produced with a diffusion burner and injected through an experimentally simulated leak into a wind tunnel (simulated workplace environment). The wind tunnel background face velocity was 0.25 m/s. Soot distributions (dg = 59 and dg = 113 nm) and TiO2 (dg = 21 nm) were used as the test aerosols. A smaller distribution of particles (dg < 8 nm) was also noticed at the injection site for soot and TiO2. Lung deposited surface area concentration was measured using a NSAM and the number size distribution was measured with a SMPS at distances of 0.9 m, 1.8 m, and 3.4 m (times of 3.6 s, 7.2 s, and 13.6 s, respectively) from the injection point. TEM images were gathered at the injection point and 3.4 m downstream. The soot (dg = 113 nm) and TiO2 (dg = 21 nm) distributions produced loose, chain-type agglomerates at the injection point with primary particle sizes of dpp = 30 nm and dpp = 4.5 nm, respectively. These distributions experienced an increase in geometric mean particle size between the injection point and 0.9 m downstream. Surface area per particle (NSAM/SMPS ratio) also increased between the injection point and 0.9 m downstream. There was no additional particle change after 0.9 m. Primary particle size also increased after the injection point within the wind tunnel. Therefore the agglomerate size change may have been caused by the primary

  2. Fate of zinc and silver engineered nanoparticles in sewerage networks.

    PubMed

    Brunetti, Gianluca; Donner, Erica; Laera, Giuseppe; Sekine, Ryo; Scheckel, Kirk G; Khaksar, Maryam; Vasilev, Krasimir; De Mastro, Giuseppe; Lombi, Enzo

    2015-06-15

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage systems before reaching wastewater treatment plants. To address this knowledge gap, laboratory-scale systems fed with raw wastewater were used to evaluate the transformation of ZnO- and Ag-NPs within sewerage transfer networks. Two experimental systems were established and spiked with either Ag- and ZnO-NPs or with their dissolved salts, and the wastewater influent and effluent samples from both systems were thoroughly characterised. X-ray absorption spectroscopy (XAS) was used to assess the extent of the chemical transformation of both forms of Zn and Ag during transport through the model systems. The results indicated that both ZnO- and Ag-NPs underwent significant transformation during their transport through the sewerage network. Reduced sulphur species represented the most important endpoint for these NPs in the sewer with slight differences in terms of speciation; ZnO converted largely to Zn sulfide, while Ag was also sorbed to cysteine and histidine. Importantly, both ionic Ag and Ag-NPs formed secondary Ag sulfide nanoparticles in the sewerage network as revealed by TEM analysis. Ag-cysteine was also shown to be a major species in biofilms. These results were verified in the field using recently developed nanoparticle in situ deployment devices (nIDDs) which were exposed directly to sewerage network conditions by immersing them into a municipal wastewater network trunk sewer and then retrieving them for XAS analysis. PMID:25841090

  3. Automotive airborne brake wear debris nanoparticles and cytokinesis-block micronucleus assay in peripheral blood lymphocytes: A pilot study.

    PubMed

    Kazimirova, Alena; Peikertova, Pavlina; Barancokova, Magdalena; Staruchova, Marta; Tulinska, Jana; Vaculik, Miroslav; Vavra, Ivo; Kukutschova, Jana; Filip, Peter; Dusinska, Maria

    2016-07-01

    Motor vehicle exhaust and non-exhaust processes play a significant role in environmental pollution, as they are a source of the finest particulate matter. Emissions from non-exhaust processes include wear-products of brakes, tires, automotive hardware, road surface, and traffic signs, but still are paid little attention to. Automotive friction composites for brake pads are composite materials which may consist of potentially hazardous materials and there is a lack of information regarding the potential influence of the brake wear debris (BWD) on the environment, especially on human health. Thus, we focused our study on the genotoxicity of the airborne fraction of BWD using a brake pad model representing an average low-metallic formulation available in the EU market. BWD was generated in the laboratory by a full-scale brake dynamometer and characterized by Raman microspectroscopy, scanning electron microscopy, and transmission electron microscopy showing that it contains nano-sized crystalline metal-based particles. Genotoxicity tested in human lymphocytes in different testing conditions showed an increase in frequencies of micronucleated binucleated cells (MNBNCs) exposed for 48h to BWD nanoparticles (NPs) (with 10% of foetal calf serum in culture medium) compared with lymphocytes exposed to medium alone, statistically significant only at the concentration 3µg/cm(2) (p=0.032). PMID:27131798

  4. Engineered silica nanoparticles as additives in lubricant oils

    NASA Astrophysics Data System (ADS)

    Díaz-Faes López, Teresa; Fernández González, Alfonso; Del Reguero, Ángel; Matos, María; Díaz-García, Marta E.; Badía-Laíño, Rosana

    2015-10-01

    Silica nanoparticles (SiO2 NPs) synthesized by the sol-gel approach were engineered for size and surface properties by grafting hydrophobic chains to prevent their aggregation and facilitate their contact with the phase boundary, thus improving their dispersibility in lubricant base oils. The surface modification was performed by covalent binding of long chain alkyl functionalities using lauric acid and decanoyl chloride to the SiO2 NP surface. The hybrid SiO2 NPs were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, simultaneous differential thermal analysis, nuclear magnetic resonance and dynamic light scattering, while their dispersion in two base oils was studied by static multiple light scattering at low (0.01% w/v) and high (0.50%w/v) concentrations. The nature of the functional layer and the functionalization degree seemed to be directly involved in the stability of the suspensions. The potential use of the functional SiO2 NPs as lubricant additives in base oils, specially designed for being used in hydraulic circuits, has been outlined by analyzing the tribological properties of the dispersions. The dendritic structure of the external layer played a key role in the tribological characteristics of the material by reducing the friction coefficient and wear. These nanoparticles reduce drastically the waste of energy in friction processes and are more environmentally friendly than other additives.

  5. Interaction of engineered nanoparticles with toxic and essential elements

    NASA Astrophysics Data System (ADS)

    Shumakova, A. A.; Gmoshinski, I. V.; Khotimchenko, S. A.; Trushina, E. N.

    2015-11-01

    Interaction of engineered nanoparticles with toxic and essential trace elements must be taken into consideration when estimating risks of NPs presented in the natural environment. The purpose of this work was to study the possible influence of silica, titanium dioxide (rutile) and fullerenol NPs on the toxicity of cadmium and to research the status of some trace elements and related indices of immune function in experiments on laboratory animals. Young male Wistar rats received cadmium salt (1 mg/kg b.w. Cd) orally for 28 days separately or in conjunction with the said kinds of NPs in different doses. A number of effects was observed as a result of combined action of Cd together with NPs, increase in bioaccumulation of this toxic trace element in the liver was most evident. The observed effects didn't show simple dose- dependence in respect to nanomaterials that should be taken into consideration when assessing the possible risks of joint action of nanoparticles and toxic elements existing in the environment in extremely low doses. Violation of microelement homeostasis caused by the combined action of Cd and NPs can have various adverse effects, such as inhibition of T-cell immunity induced by co-administration of Cd with rutile NPs.

  6. Mesoporous silica nanoparticles in tissue engineering--a perspective.

    PubMed

    Rosenholm, Jessica Maria; Zhang, Jixi; Linden, Mika; Sahlgren, Cecilia

    2016-02-01

    In this review, we summarize the latest developments and give a perspective on future applications of mesoporous silica nanoparticles (MSNs) in regenerative medicine. MSNs constitute a flexible platform for controlled delivery of drugs and imaging agents in tissue engineering and stem cell therapy. We highlight the recent advances in applying MSNs for controlled drug delivery and stem cell tracking. We touch upon novel functions of MSNs in real time imaging of drug release and biological function, and as tools to control the chemical and mechanical environment of stem cells. We discuss the need for novel model systems for studying biofunctionality and biocompatibility of MSNs, and how the interdisciplinary activities within the field will advance biotechnology research. PMID:26784861

  7. Engineered Upconversion Nanoparticles for Resolving Protein Interactions inside Living Cells.

    PubMed

    Drees, Christoph; Raj, Athira Naduviledathu; Kurre, Rainer; Busch, Karin B; Haase, Markus; Piehler, Jacob

    2016-09-12

    Upconversion nanoparticles (UCNPs) convert near-infrared into visible light at much lower excitation densities than those used in classic two-photon absorption microscopy. Here, we engineered <50 nm UCNPs for application as efficient lanthanide resonance energy transfer (LRET) donors inside living cells. By optimizing the dopant concentrations and the core-shell structure for higher excitation densities, we observed enhanced UCNP emission as well as strongly increased sensitized acceptor fluorescence. For the application of these UCNPs in complex biological environments, we developed a biocompatible surface coating functionalized with a nanobody recognizing green fluorescent protein (GFP). Thus, rapid and specific targeting to GFP-tagged fusion proteins in the mitochondrial outer membrane and detection of protein interactions by LRET in living cells was achieved. PMID:27510808

  8. Engineering Metallic Nanoparticles for Enhancing and Probing Catalytic Reactions.

    PubMed

    Collins, Gillian; Holmes, Justin D

    2016-07-01

    Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs. PMID:26823380

  9. Ordered nanoparticle arrays formed on engineered chaperonin protein templates.

    SciTech Connect

    McMillan, R. A.; Paavola, C. D.; Howard, J.; Chan, S. L.; Zaluzec, N. J.; Trent, J. D.; Materials Science Division; NASA Ames Research Center; SETI Inst.

    2002-12-01

    Traditional methods for fabricating nanoscale arrays are usually based on lithographic techniques. Alternative new approaches rely on the use of nanoscale templates made of synthetic or biological materials. Some proteins, for example, have been used to form ordered two-dimensional arrays. Here, we fabricated nanoscale ordered arrays of metal and semiconductor quantum dots by binding preformed nanoparticles onto crystalline protein templates made from genetically engineered hollow double-ring structures called chaperonins. Using structural information as a guide, a thermostable recombinant chaperonin subunit was modified to assemble into chaperonins with either 3 nm or 9 nm apical pores surrounded by chemically reactive thiols. These engineered chaperonins were crystallized into two-dimensional templates up to 20 m in diameter. The periodic solvent-exposed thiols within these crystalline templates were used to size-selectively bind and organize either gold (1.4, 5 or 10nm) or CdSe-ZnS semiconductor (4.5 nm) quantum dots into arrays. The order within the arrays was defined by the lattice of the underlying protein crystal. By combining the self-assembling properties of chaperonins with mutations guided by structural modelling, we demonstrate that quantum dots can be manipulated using modified chaperonins and organized into arrays for use in next-generation electronic and photonic devices.

  10. Engineering structured light with Vogel spiral arrays of nanoparticles

    NASA Astrophysics Data System (ADS)

    Lawrence, Nate; Trevino, Jacob; Dal Negro, Luca

    2013-03-01

    We present a general analytical model for light scattering by arbitrary Vogel spiral arrays of circular apertures uniformly illuminated at normal incidence. This model suffices to unveil the fundamental mathematical structure of their complex Fraunhofer diffraction patterns and enables the engineering of optical beams carrying multiple values of orbital angular momentum (OAM). By performing analytical Fourier-Hankel decomposition of spiral arrays and far field patterns, we rigorously demonstrate the ability to encode specific numerical sequences onto the OAM values of diffracted optical beams. In particular, we show that these OAM values are determined by the rational approximations of the continued fraction expansions of the irrational angles utilized to generate Vogel spirals. Finally, we experimentally demonstrate structured light carrying multiple values of OAM in the far-field scattering region of Vogel spiral arrays of metallic nanoparticles. Using Fourier-Hankel mode decomposition analysis and interferometric reconstruction of the complex amplitude of scattered waves, we show the ability to encode well-defined numerical sequences, determined by the aperiodic spiral geometry, into azimuthal OAM values, in excellent agreement with analytical scattering theory. The generation of sequences of OAM values by light scattering from engineered aperiodic surfaces is relevant to a number of device applications for secure optical communication, classical and quantum cryptography.

  11. Systemic delivery to central nervous system by engineered PLGA nanoparticles.

    PubMed

    Cai, Qiang; Wang, Long; Deng, Gang; Liu, Junhui; Chen, Qianxue; Chen, Zhibiao

    2016-01-01

    Neurological disorders are an important global public health problem, but pharmaceutical treatments are limited due to drug access to the central nervous system being restricted by the blood-brain barrier (BBB). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are one of the most promising drug and gene delivery systems for crossing the BBB. While these systems offer great promise, PLGA NPs also have some intrinsic drawbacks and require further engineering for clinical and research applications. Multiple strategies have been developed for using PLGA NPs to deliver compounds across the BBB. We classify these strategies into three categories according to the adaptations made to the PLGA NPs (1) to facilitate travel from the injection site (pre-transcytosis strategies); (2) to enhance passage across the brain endothelial cells (BBB transcytosis strategies) and (3) to achieve targeting of the impaired nervous system cells (post-transcytosis strategies). PLGA NPs modified according to these three strategies are denoted first, second, and third generation NPs, respectively. We believe that fusing these three strategies to engineer multifunctional PLGA NPs is the only way to achieve translational applications. PMID:27158367

  12. Ordered nanoparticle arrays formed on engineered chaperonin protein templates

    NASA Technical Reports Server (NTRS)

    McMillan, R. Andrew; Paavola, Chad D.; Howard, Jeanie; Chan, Suzanne L.; Zaluzec, Nestor J.; Trent, Jonathan D.

    2002-01-01

    Traditional methods for fabricating nanoscale arrays are usually based on lithographic techniques. Alternative new approaches rely on the use of nanoscale templates made of synthetic or biological materials. Some proteins, for example, have been used to form ordered two-dimensional arrays. Here, we fabricated nanoscale ordered arrays of metal and semiconductor quantum dots by binding preformed nanoparticles onto crystalline protein templates made from genetically engineered hollow double-ring structures called chaperonins. Using structural information as a guide, a thermostable recombinant chaperonin subunit was modified to assemble into chaperonins with either 3 nm or 9 nm apical pores surrounded by chemically reactive thiols. These engineered chaperonins were crystallized into two-dimensional templates up to 20 microm in diameter. The periodic solvent-exposed thiols within these crystalline templates were used to size-selectively bind and organize either gold (1.4, 5 or 10nm) or CdSe-ZnS semiconductor (4.5 nm) quantum dots into arrays. The order within the arrays was defined by the lattice of the underlying protein crystal. By combining the self-assembling properties of chaperonins with mutations guided by structural modelling, we demonstrate that quantum dots can be manipulated using modified chaperonins and organized into arrays for use in next-generation electronic and photonic devices.

  13. Strategies in biomimetic surface engineering of nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Gong, Yong-Kuan; Winnik, Françoise M.

    2012-01-01

    Engineered nanoparticles (NPs) play an increasingly important role in biomedical sciences and in nanomedicine. Yet, in spite of significant advances, it remains difficult to construct drug-loaded NPs with precisely defined therapeutic effects, in terms of release time and spatial targeting. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Upon injection in the blood stream or following oral administation, NPs have to bypass numerous barriers prior to reaching their intended target. A particularly successful design strategy consists in masking the NP to the biological environment by covering it with an outer surface mimicking the composition and functionality of the cell's external membrane. This review describes this biomimetic approach. First, we outline key features of the composition and function of the cell membrane. Then, we present recent developments in the fabrication of molecules that mimic biomolecules present on the cell membrane, such as proteins, peptides, and carbohydrates. We present effective strategies to link such bioactive molecules to the NPs surface and we highlight the power of this approach by presenting some exciting examples of biomimetically engineered NPs useful for multimodal diagnostics and for target-specific drug/gene delivery applications. Finally, critical directions for future research and applications of biomimetic NPs are suggested to the readers.

  14. Systemic delivery to central nervous system by engineered PLGA nanoparticles

    PubMed Central

    Cai, Qiang; Wang, Long; Deng, Gang; Liu, Junhui; Chen, Qianxue; Chen, Zhibiao

    2016-01-01

    Neurological disorders are an important global public health problem, but pharmaceutical treatments are limited due to drug access to the central nervous system being restricted by the blood-brain barrier (BBB). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are one of the most promising drug and gene delivery systems for crossing the BBB. While these systems offer great promise, PLGA NPs also have some intrinsic drawbacks and require further engineering for clinical and research applications. Multiple strategies have been developed for using PLGA NPs to deliver compounds across the BBB. We classify these strategies into three categories according to the adaptations made to the PLGA NPs (1) to facilitate travel from the injection site (pre-transcytosis strategies); (2) to enhance passage across the brain endothelial cells (BBB transcytosis strategies) and (3) to achieve targeting of the impaired nervous system cells (post-transcytosis strategies). PLGA NPs modified according to these three strategies are denoted first, second, and third generation NPs, respectively. We believe that fusing these three strategies to engineer multifunctional PLGA NPs is the only way to achieve translational applications. PMID:27158367

  15. Nanoparticle emission assessment technique (NEAT) for the identification and measurement of potential inhalation exposure to engineered nanomaterials--part A.

    PubMed

    Methner, M; Hodson, L; Geraci, C

    2010-03-01

    There are currently no exposure limits specific to engineered nanomaterial nor any national or international consensus standards on measurement techniques for nanomaterials in the workplace. However, facilities engaged in the production and use of engineered nanomaterials have expressed an interest in learning whether the potential for worker exposure exists. To assist with answering this question, the National Institute for Occupational Safety and Health established a nanotechnology field research team whose primary goal was to visit facilities and evaluate the potential for release of nanomaterials and worker exposure. The team identified numerous techniques to measure airborne nanomaterials with respect to particle size, mass, surface area, number concentration, and composition. However, some of these techniques lack specificity and field portability and are difficult to use and expensive when applied to routine exposure assessment. This article describes the nanoparticle emission assessment technique (NEAT) that uses a combination of measurement techniques and instruments to assess potential inhalation exposures in facilities that handle or produce engineered nanomaterials. The NEAT utilizes portable direct-reading instrumentation supplemented by a pair of filter-based air samples (source-specific and personal breathing zone). The use of the filter-based samples are crucial for identification purposes because particle counters are generally insensitive to particle source or composition and make it difficult to differentiate between incidental and process-related nanomaterials using number concentration alone. Results from using the NEAT at 12 facilities are presented in the companion article (Part B) in this issue. PMID:20017054

  16. Colloidal microcapsules: Surface engineering of nanoparticles for interfacial assembly

    NASA Astrophysics Data System (ADS)

    Patra, Debabrata

    2011-12-01

    Colloidal Microcapsules (MCs), i.e. capsules stabilized by nano-/microparticle shells are highly modular inherently multi-scale constructs with applications in many areas of material and biological sciences e.g. drug delivery, encapsulation and microreactors. These MCs are fabricated by stabilizing emulsions via self-assembly of colloidal micro/nanoparticles at liquid-liquid interface. In these systems, colloidal particles serve as modular building blocks, allowing incorporation of the particle properties into the functional capabilities of the MCs. As an example, nanoparticles (NPs) can serve as appropriate antennae to induce response by external triggers (e.g. magnetic fields or laser) for controlled release of encapsulated materials. Additionally, the dynamic nature of the colloidal assembly at liquid-liquid interfaces result defects free organized nanostructures with unique electronic, magnetic and optical properties which can be tuned by their dimension and cooperative interactions. The physical properties of colloidal microcapsules such as permeability, mechanical strength, and biocompatibility can be precisely controlled through the proper choice of colloids and preparation conditions for their. This thesis illustrates the fabrication of stable and robust MCs through via chemical crosslinking of the surface engineered NPs at oil-water interface. The chemical crosslinking assists NPs to form a stable 2-D network structure at the emulsion interface, imparting robustness to the emulsions. In brief, we developed the strategies for altering the nature of chemical interaction between NPs at the emulsion interface and investigated their role during the self-assembly process. Recently, we have fabricated stable colloidal microcapsule (MCs) using covalent, dative as well as non-covalent interactions and demonstrated their potential applications including encapsulation, size selective release, functional devices and biocatalysts.

  17. Mobility of engineered inorganic nanoparticles in porous media

    NASA Astrophysics Data System (ADS)

    Metreveli, George; Heidmann, Ilona; Schaumann, Gabriele Ellen

    2013-04-01

    Besides the excellent properties and great potential for various industrial, medical, pharmaceutical, cosmetic, and life science applications, engineered inorganic nanoparticles (EINP) can show also disadvantages concerning increasing risk potential with increasing application, if they are released in the environmental systems. EINP can influence microbial activity and can show toxic effects (Fabrega et al., 2009). Similar to the inorganic natural colloids, EINP can be transported in soil and groundwater systems (Metreveli et al., 2005). Furthermore, due to the large surface area and high sorption and complex formation capacity, EINP can facilitate transport of different contaminants. In this study the mobility behaviour of EINP and their effect on the transport of different metal(loid) species in water saturated porous media was investigated. For these experiments laboratory column system was used. The column was filled with quartz sand. The interactions between EINP and metal(loid)s were characterised by coupling of asymmetrical flow field flow fractionation (AF4) with inductively coupled plasma mass spectrometer (ICP-MS). As EINP laponite (synthetic three layer clay mineral), and as metal(loid)s Cu, Pb, Zn, Pt and As were used. In AF4 experiments sorption of metal(loid)s on the surface of EINP could be observed. The extent of interactions was influenced by pH value and was different for different metal(loid)s. Laboratory column experiments showed high mobility of EINP, which facilitated transport of most of metal(loid)s in water saturated porous media. Furthermore the migration of synthetic silver nanoparticles in natural soil columns was determined in leaching experiments. Acknowledgement Financial support by German Research Council (DFG) and Max-Buchner-Research Foundation (MBFSt) is gratefully acknowledged. We thank Karlsruhe Institute of Technology (KIT) for the opportunity to perform the column and AF4 experiments. References: Fabrega, J., Fawcett, S. R

  18. Manufactured and Airborne Nanoparticle Cardiopulmonary Interactions: A Review of Mechanisms and the Possible Contribution of Mast Cells

    PubMed Central

    Shannahan, Jonathan H.; Kodavanti, Urmila P.; Brown, Jared M.

    2013-01-01

    Human inhalation exposures to manufactured nanoparticles (NP) and airborne ultrafine particles (UFP) continues to increase in both occupational and environmental settings. UFP exposures have been associated with increased cardiovascular mortality and morbidity, while ongoing research supports adverse systemic and cardiovascular health effects after NP exposures. Adverse cardiovascular health effects include alterations in heart rate variability, hypertension, thrombosis, arrhythmias, increased myocardial infarction, and atherosclerosis. Exactly how UFP and NP cause these negative cardiovascular effects is poorly understood, however a variety of mediators and mechanisms have been proposed. UFP and NP, as well as their soluble components, are known to systemically translocate from the lung. Translocated particles could mediate cardiovascular toxicity through direct interactions with the vasculature, blood, and heart. Recent study suggests that sensory nerve stimulation within the lung may also contribute to UFP- and NP-induced acute cardiovascular alterations. Activation of sensory nerves, such as C-fibers, within the lung may result in altered cardiac rhythm and function. Lastly, release of pulmonary-derived mediators into systemic circulation has been proposed to facilitate cardiovascular effects. In general, these proposed pulmonary-derived mediators include pro-inflammatory cytokines, oxidatively-modified macromolecules, vasoactive proteins, and prothrombotic factors. These pulmonary-derived mediators have been postulated to contribute to the subsequent prothrombotic, atherogenic, and inflammatory effects after exposure. This review will evaluate the potential contribution of individual mediators and mechanisms in facilitating cardiopulmonary toxicity following inhalation of UFP and NP. Lastly we will appraise the literature and propose a hypothesis regarding the possible role of mast cells in contributing to these systemic effects. PMID:22486349

  19. Comparative modeling of exposure to airborne nanoparticles released by consumer spray products.

    PubMed

    Riebeling, Christian; Luch, Andreas; Götz, Mario Enrico

    2016-04-01

    Consumer exposure to sprays containing nano-objects is a continuing concern as a potential health hazard. One potential hazard has been formulated in the overload hypothesis. It describes a volume fraction of the macrophages that is occupied by deposited nanoparticles that leads to reduced macrophage mobility. Subsequent chronic inflammation may then lead to severe health consequences including cancer. To calculate lung deposition of spherical particles, the Multiple-Path Particle Dosimetry (MPPD) model (ARA, Albuquerque, NM) provides different kinds of lung models and age settings. Using the MPPD v 2.11 software, we modeled several consumer-related exposure scenarios. Different body orientations and age groups were investigated. Moreover, a number of materials representing different densities were used, and the exposure calculated using MPPD is compared to the hazard derived from the overload hypothesis. Conditions leading to macrophage overload were found for exposures to high particle doses for prolonged times and repeated exposure. Such conditions are unlikely in the context of regular consumer exposure. The overload hypothesis assumes the particles to be inert and biopersistent, a condition that currently lacks a clear regulatory definition and is valid only for a few selected materials. Furthermore, because of material-specific effects and the possibility of surface adsorption of hazardous chemicals, nano-objects in propellant sprays remain of concern for consumer health. PMID:26418667

  20. Endocytosis of Nanomedicines: The Case of Glycopeptide Engineered PLGA Nanoparticles

    PubMed Central

    Vilella, Antonietta; Ruozi, Barbara; Belletti, Daniela; Pederzoli, Francesca; Galliani, Marianna; Semeghini, Valentina; Forni, Flavio; Zoli, Michele; Vandelli, Maria Angela; Tosi, Giovanni

    2015-01-01

    The success of nanomedicine as a new strategy for drug delivery and targeting prompted the interest in developing approaches toward basic and clinical neuroscience. Despite enormous advances on brain research, central nervous system (CNS) disorders remain the world’s leading cause of disability, in part due to the inability of the majority of drugs to reach the brain parenchyma. Many attempts to use nanomedicines as CNS drug delivery systems (DDS) were made; among the various non-invasive approaches, nanoparticulate carriers and, particularly, polymeric nanoparticles (NPs) seem to be the most interesting strategies. In particular, the ability of poly-lactide-co-glycolide NPs (PLGA-NPs) specifically engineered with a glycopeptide (g7), conferring to NPs’ ability to cross the blood brain barrier (BBB) in rodents at a concentration of up to 10% of the injected dose, was demonstrated in previous studies using different routes of administrations. Most of the evidence on NP uptake mechanisms reported in the literature about intracellular pathways and processes of cell entry is based on in vitro studies. Therefore, beside the particular attention devoted to increasing the knowledge of the rate of in vivo BBB crossing of nanocarriers, the subsequent exocytosis in the brain compartments, their fate and trafficking in the brain surely represent major topics in this field. PMID:26102358

  1. Galactose engineered solid lipid nanoparticles for targeted delivery of doxorubicin.

    PubMed

    Jain, Ashay; Kesharwani, Prashant; Garg, Neeraj K; Jain, Atul; Jain, Som Akshay; Jain, Amit Kumar; Nirbhavane, Pradip; Ghanghoria, Raksha; Tyagi, Rajeev Kumar; Katare, Om Prakash

    2015-10-01

    The present investigation reports the preparation, optimization, and characterization of surface engineered solid lipid nanoparticles (SLNs) encapsulated with doxorubicin (DOX). Salient features such as biocompatibility, controlled release, target competency, potential of penetration, improved physical stability, low cost and ease of scaling-up make SLNs viable alternative to liposomes for effective drug delivery. Galactosylation of SLNs instructs some gratifying characteristic, which leads to the evolution of promising delivery vehicles. The impendence of lectin receptors on different cell surfaces makes the galactosylated carriers admirable for targeted delivery of drugs to ameliorate their therapeutic index. Active participation of some lectin receptors in immune responses to antigen overlaid the application of galactosylated carriers in delivery of antigen and immunotherapy for treatment of maladies like cancer. These advantages revealed the promising potential of galactosylated carriers in each perspective of drug delivery. The developed DOX loaded galactosylated SLNs formulation was found to have particle size 239 ± 2.40 nm, PDI 0.307 ± 0.004, entrapment efficiency 72.3 ± 0.9%. Higher cellular uptake, cytotoxicity, and nuclear localization of galactosylated SLNs against A549 cells revealed higher efficiency of the formulation. In a nutshell, the galactosylation strategy with SLNs could be a promising approach in improving the delivery of DOX for cancer therapy. PMID:26142628

  2. Transport of engineered nanoparticles in partially saturated sand columns.

    PubMed

    Yecheskel, Yinon; Dror, Ishai; Berkowitz, Brian

    2016-07-01

    The vadose zone is a critical region controlling fate and transport of contaminants in soils and, ultimately, groundwater. It is therefore important to understand the behavior of engineered nanoparticles (ENPs) in this zone, as a potential group of emerging contaminants. Soil is a significant sink for ENPs; however, only a few studies have considered the fate and transport of ENPs in partially saturated systems, representative of the vadose zone. Here, transport behavior of three commonly used ENPs - gold (Au-NPs), silver (Ag-NPs) and zinc oxide (ZnO-NPs) - is investigated in partially saturated sand columns. High mobilities of Au-NPs and Ag-NPs under different water saturation levels and concentrations were observed. The presence of CaCl2 reduces Ag-NP mobility through chemical interactions, similar to behavior reported in saturated systems. Furthermore, transformation of Ag-NPs in the environment may influence their mobility; aging of Ag-NPs following sulfidation was investigated. The silver sulfide (Ag2S-NPs) remained stable in aqueous suspension, and mobile in the partially saturated sand column. In contrast, the positively-charged ZnO-NPs were completely immobilized in the sand column. Significantly, though, addition of humic acid (HA) to the ZnO-NP suspension reverses particle surface charge and thus increases their mobility. Moreover, remobilization of entrapped ZnO-NPs by HA was demonstrated. PMID:26995325

  3. Enzyme sensitive, surface engineered nanoparticles for enhanced delivery of camptothecin.

    PubMed

    Yu, Hongliang; Chen, Jiao; Liu, Sen; Lu, Qian; He, Jian; Zhou, Zhengyang; Hu, Yong

    2015-10-28

    To achieve a drug delivery system combining the programmable long circulation and targeting ability, surface engineering nanoparticles (NPs), having a sandwich structure consisting of a long circulating outmost layer, a targeting middle layer and a hydrophobic innermost core were constructed by mixing a matrix metalloproteinase MMP2 and MMP9-sensitive copolymers (mPEG-Pep-PCL) and folate receptor targeted copolymers (FA-PEG-PCL). Their physiochemical traits including morphology, particle size, drug loading content, and in vitro release profiles were studied. In vitro studies validated that the inhibition efficiency of tumor cells was effectively correlated with NP concentrations. Furthermore, The PEG layer would detach from the NPs due to the up-regulated extracellular MMP2 and MMP9 in tumors, resulting in the exposure of folate to enhance the cellular internalization via folate receptor mediated endocytosis, which accelerated the release rate of CPT in vivo. The antitumor efficacy, tumor targeting ability and bio-distribution of the NPs were examined in a B16 melanoma cells xenograft mouse model. These NPs showed improved tumor target ability and enhanced aggregation of camptothecin (CPT) in tumor site and prominent suppression of tumor growth. Thus this mPEG-Pep-PCL@FA-PEG-PCL core-shell structure NP could be a better candidate for the tumor specific delivery of hydrophobic drug. PMID:26282096

  4. Risks from accidental exposures to engineered nanoparticles and neurological health effects: A critical review

    PubMed Central

    2010-01-01

    There are certain concerns regarding the safety for the environment and human health from the use of engineered nanoparticles (ENPs) which leads to unintended exposures, as opposed to the use of ENPs for medical purposes. This review focuses on the unintended human exposure of ENPs. In particular, possible effects in the brain are discussed and an attempt to assess risks is performed. Animal experiments have shown that investigated ENPs (metallic nanoparticles, quantum dots, carbon nanotubes) can translocate to the brain from different entry points (skin, blood, respiratory pathways). After inhalation or instillation into parts of the respiratory tract a very small fraction of the inhaled or instilled ENPs reaches the blood and subsequently secondary organs, including the CNS, at a low translocation rate. Experimental in vivo and in vitro studies have shown that several types of ENPs can have various biological effects in the nervous system. Some of these effects could also imply that ENPs can cause hazards, both acutely and in the long term. The relevance of these data for risk assessment is far from clear. There are at present very few data on exposure of the general public to either acute high dose exposure or on chronic exposure to low levels of air-borne ENPs. It is furthermore unlikely that acute high dose exposures would occur. The risk from such exposures for damaging CNS effects is thus probably very low, irrespective of any biological hazard associated with ENPs. The situation is more complicated regarding chronic exposures, at low doses. The long term accumulation of ENPs can not be excluded. However, we do not have exposure data for the general public regarding ENPs. Although translocation to the brain via respiratory organs and the circulation appears to be very low, there remains a possibility that chronic exposures, and/or biopersistent ENPs, can influence processes within the brain that are triggering or aggravating pathological processes. In

  5. Environmental Feedbacks and Engineered Nanoparticles: Mitigation of Silver Nanoparticle Toxicity to Chlamydomonas reinhardtii by Algal-Produced Organic Compounds

    PubMed Central

    Stevenson, Louise M.; Dickson, Helen; Klanjscek, Tin; Keller, Arturo A.; McCauley, Edward; Nisbet, Roger M.

    2013-01-01

    The vast majority of nanotoxicity studies measures the effect of exposure to a toxicant on an organism and ignores the potentially important effects of the organism on the toxicant. We investigated the effect of citrate-coated silver nanoparticles (AgNPs) on populations of the freshwater alga Chlamydomonas reinhardtii at different phases of batch culture growth and show that the AgNPs are most toxic to cultures in the early phases of growth. We offer strong evidence that reduced toxicity occurs because extracellular dissolved organic carbon (DOC) compounds produced by the algal cells themselves mitigate the toxicity of AgNPs. We analyzed this feedback with a dynamic model incorporating algal growth, nanoparticle dissolution, bioaccumulation of silver, DOC production and DOC-mediated inactivation of nanoparticles and ionic silver. Our findings demonstrate how the feedback between aquatic organisms and their environment may impact the toxicity and ecological effects of engineered nanoparticles. PMID:24086348

  6. Metal nanoparticles in diesel exhaust derived by in-cylinder melting of detached engine fragments

    NASA Astrophysics Data System (ADS)

    Liati, Anthi; Pandurangi, Sushant Sunil; Boulouchos, Konstantinos; Schreiber, Daniel; Arroyo Rojas Dasilva, Yadira

    2015-01-01

    A wide range of environmental and health effects are linked to combustion-generated pollutants related to traffic. Nanoparticles, in particular, are a major concern for humans since they can be inhaled and have potentially toxic effects. The variability and sources of combustion-related nanoparticle pollutants remain inadequately investigated. Here we report the presence of ca. 5-100 nm large Fe3O4 nanoparticles, in form of agglomerates, in diesel exhaust. The mode of occurrence of these nanoparticles, in combination with their chemical composition matching that of steel indicate that they derive by melting of engine fragments in the combustion chamber and subsequent crystallization during cooling. To evaluate this hypothesis, we applied CFD simulations of material transport in the cylinder of a diesel engine, assuming detachment of steel fragments from various sites of the cylinder. The CFD results show that fragments ≤20 μm in size dislodged from the piston surface or from the fuel nozzle interior can be indeed transported to such hot areas of the combustion chamber where they can melt. The simulation results concur with the experimental observations and point out that metal nanoparticle formation by in-cylinder melting of engine fragments can occur in diesel engines. The present study proposes a hitherto neglected formation mechanism of metal nanoparticle emissions from internal combustion engines raising possible environmental and health concerns, especially in urban areas.

  7. Shape Control in Engineering of Polymeric Nanoparticles for Therapeutic Delivery

    PubMed Central

    Williford, John-Michael; Santos, Jose Luis; Shyam, Rishab; Mao, Hai-Quan

    2015-01-01

    Nanoparticle-mediated delivery of therapeutics holds great potential for the diagnosis and treatment of a wide range of diseases. Significant advances have been made in the design of new polymeric nanoparticle carriers through modulation of their physical and chemical structures and biophysical properties. Nanoparticle shape has been increasingly proposed as an important attribute dictating their transport properties in biological milieu. In this review, we highlight three major methods for preparing polymeric nanoparticles that allow for exquisite control of particle shape. Special attention is given to various approaches to controlling nanoparticle shape by tuning copolymer structural parameters and assembly conditions. This review also provides comparisons of these methods in terms of their unique capabilities, materials choices, and specific delivery cargos, and summarizes the biological effects of nanoparticle shape on transport properties at the tissue and cellular levels. PMID:26146550

  8. Impact of engineered zinc oxide nanoparticles on the energy budgets of Mytilus galloprovincialis

    NASA Astrophysics Data System (ADS)

    Muller, Erik B.; Hanna, Shannon K.; Lenihan, Hunter S.; Miller, Robert J.; Nisbet, Roger M.

    2014-11-01

    This paper characterizes the sublethal impact of engineered ZnO nanoparticles on the individual performance of the marine mussel Mytilus galloprovincialis within the context of Dynamic Energy Budget theory, thereby allowing an integrated evaluation of the impact of multiple stressors on various endpoints. Data include measurements of the impact of ZnO nanoparticles on body burden, feeding, respiration, shell length, biomass, and mortality of mussels kept in laboratory tanks for over 100 days. ZnO nanoparticles in the environment impair the mussels' feeding rate (EC50 for the maximum feeding rate is 1.5 mg ZnO nanoparticles L- 1). Zn accumulated in tissue increases respiration (EC50 for the respiration rate is 0.9 mg environmental ZnO nanoparticles L- 1 with the body burden having reached its ultimate level), indicating that maintenance processes are more affected by ZnO nanoparticles than feeding. The feeding regime constrained growth and biomass production to the extent that the impact of ZnO nanoparticles on these processes was undetectable, yet the remaining measurements allowed the estimation of the toxicity parameters. The toxicity representation, combined with the DEB model, allowed the calculation of the effect of the nanoparticles on the expected lifetime production of reproductive matter. EC50 for the expected lifetime production of reproductive matter is less than 0.25 mg ZnO nanoparticles L- 1, indicating that that the ecological impact of ZnO nanoparticle exposure is stronger than its impact on individual physiological rates.

  9. Transport of engineered zeolite and natural nanoparticles in porous media

    NASA Astrophysics Data System (ADS)

    Keller, A. A.; Wang, P.

    2007-12-01

    There are many natural nanoparticles (NPs) that are ubiquitous in the environment such as soil and sediment colloids. In addition, many new engineered NPs, such as tailored zeolites, are being developed for applications in which they may be released into the environment. The fate and transport of the NPs is very much related with contaminant fate and transport. This study focused on transport of engineered zeolite nanoparticles (NPs) and natural soil and sediment colloidal NPs within porous media under saturated conditions. Clean medium-sized sand grains were used as the porous media and NPs were injected into the column as a pulse. KCl or CaCl2 with varying concentrations was used as background electrolyte. The results showed that, interestingly, the zeta- potential of the natural colloids and Zeolite-Ca decreased (more negative) with increasing KCl concentration while increased (less negative) with increasing CaCl2 concentration. This unexpected results was attributed to the fact that the natural colloids and Zeolite-Ca are saturated with divalent cations (Ca2+ and/or Mg2+) originally and the replacement of these divalent cations with K+ on the colloid surfaces caused the zeta-potential to drop with increasing KCl concentrations. The zeta-potential measurement of Zeolite-K increased with either KCl or CaCl2 concentration. Consistently early breakthrough was observed for NP compared with conservative tracers (KCL or CaCl2) and the effect was more pronounced with higher water flowrate. Zeolite-K showed significantly higher degree of transport (defined as percent of NPs transported out of the column) than Zeolite-Ca under the otherwise same conditions. With KCl as the background electrolyte, the significantly higher NP transport was observed than with CaCl2. Overall, as the ionic strength of the flowing fluid increased, the transport of the NPs decreased, largely due to the compressed double layer under the higher ionic strength. Besides, as the flow rate of the

  10. Engineered nanoparticles. How brain friendly is this new guest?

    PubMed

    Cupaioli, Francesca A; Zucca, Fabio A; Boraschi, Diana; Zecca, Luigi

    2014-01-01

    In the last 30 years, the use of engineered nanoparticles (NPs) has progressively increased in many industrial and medical applications. In therapy, NPs may allow more effective cellular and subcellular targeting of drugs. In diagnostic applications, quantum dots are exploited for their optical characteristics, while superparamagnetic iron oxides NPs are used in magnetic resonance imaging. NPs are used in semiconductors, packaging, textiles, solar cells, batteries and plastic materials. Despite the great progress in nanotechnologies, comparatively little is known to date on the effects that exposure to NPs may have on the human body, in general and specifically on the brain. NPs can enter the human body through skin, digestive tract, airways and blood and they may cross the blood-brain barrier to reach the central nervous system. In addition to the paucity of studies describing NP effects on brain function, some of them also suffer of insufficient NPs characterization, inadequate standardization of conditions and lack of contaminant evaluation, so that results from different studies can hardly be compared. It has been shown in vitro and in vivo in rodents that NPs can impair dopaminergic and serotoninergic systems. Changes of neuronal morphology and neuronal death were reported in mice treated with NPs. NPs can also affect the respiratory chain of mitochondria and Bax protein levels, thereby causing apoptosis. Changes in expression of genes involved in redox pathways in mouse brain regions were described. NPs can induce autophagy, and accumulate in lysosomes impairing their degradation capacity. Cytoskeleton and vesicle trafficking may also be affected. NPs treated animals showed neuroinflammation with microglia activation, which could induce neurodegeneration. Considering the available data, it is important to design adequate models and experimental systems to evaluate in a reliable and controlled fashion the effects of NPs on the brain, and generate data

  11. Dysregulation of Macrophage Activation Profiles by Engineered Nanoparticles

    SciTech Connect

    Kodali, Vamsi; Littke, Matthew H.; Tilton, Susan C.; Teeguarden, Justin G.; Shi, Liang; Frevert, Charles W.; Wang, Wei; Pounds, Joel G.; Thrall, Brian D.

    2013-08-27

    Although the potential human health impacts from exposure to engineered nanoparticles (ENPs) are uncertain, past epidemiological studies have established correlations between exposure to ambient air pollution particulates and the incidence of pneumonia and lung infections. Using amorphous silica and superparamagnetic iron oxide (SPIO) as model high production volume ENPs, we examined how macrophage activation by bacterial lipopolysaccharide (LPS) or the lung pathogen Streptococcus pneumoniae is altered by ENP pretreatment. Neither silica nor SPIO treatment elicited direct cytotoxic or pro-inflammatory effects in bone marrow-derived macrophages. However, pretreatment of macrophages with SPIO caused extensive reprogramming of nearly 500 genes regulated in response to LPS challenge, hallmarked by exaggerated activation of oxidative stress response pathways and suppressed activation of both pro- and anti-inflammatory pathways. Silica pretreatment altered regulation of only 67 genes, but there was strong correlation with gene sets affected by SPIO. Macrophages exposed to SPIO displayed a phenotype suggesting an impaired ability to transition from an M1 to M2-like activation state, characterized by suppressed IL-10 induction, enhanced TNFα production, and diminished phagocytic activity toward S. pneumoniae. Studies in macrophages deficient in scavenger receptor A (SR-A) showed SR-A participates in cell uptake of both the ENPs and S. pneumonia and co-regulates the anti-inflammatory IL-10 pathway. Thus, mechanisms for dysregulation of innate immunity exist by virtue that common receptor recognition pathways are used by some ENPs and pathogenic bacteria, although the extent of transcriptional reprogramming of macrophage function depends on the physicochemical properties of the ENP after internalization. Our results also illustrate that biological effects of ENPs may be indirectly manifested only after challenging normal cell function. Finally, nanotoxicology screening

  12. Dysregulation of Macrophage Activation Profiles by Engineered Nanoparticles

    PubMed Central

    Kodali, Vamsi; Littke, Matthew H.; Tilton, Susan C.; Teeguarden, Justin G.; Shi, Liang; Frevert, Charles W.; Wang, Wei; Pounds, Joel G.; Thrall, Brian D.

    2013-01-01

    Although the potential human health impacts from exposure to engineered nanoparticles (ENPs) are uncertain, past epidemiological studies have established correlations between exposure to ambient air pollution particulates and the incidence of pneumonia and lung infections. Using amorphous silica and superparamagnetic iron oxide (SPIO) as model high production volume ENPs, we examined how macrophage activation by bacterial lipopolysaccharide (LPS) or the lung pathogen Streptococcus pneumoniae is altered by ENP pre-treatment. Neither silica nor SPIO treatment elicited direct cytotoxic or pro-inflammatory effects in bone marrow-derived macrophages. However, pre-treatment of macrophages with SPIO caused extensive reprogramming of nearly 500 genes regulated in response to LPS challenge, hallmarked by exaggerated activation of oxidative stress response pathways and suppressed activation of both pro- and anti-inflammatory pathways. Silica pre-treatment altered regulation of only 67 genes, but there was strong correlation with gene sets affected by SPIO. Macrophages exposed to SPIO displayed a phenotype suggesting an impaired ability to transition from a M1 to M2-like activation state, characterized by suppressed IL-10 induction, enhanced TNFα production, and diminished phagocytic activity toward S. pneumoniae. Studies in macrophages deficient in scavenger receptor A (SR-A) showed SR-A participates in cell uptake of both the ENPs and S. pneumonia, and co-regulates the anti-inflammatory IL-10 pathway. Thus, mechanisms for dysregulation of innate immunity exist by virtue that common receptor recognition pathways are used by some ENPs and pathogenic bacteria, although the extent of transcriptional reprogramming of macrophage function depends on the physicochemical properties of the ENP after internalization. Our results also illustrate that biological effects of ENPs may be indirectly manifested only after challenging normal cell function. Nanotoxicology screening strategies

  13. Assembly of surface engineered nanoparticles for functional materials

    NASA Astrophysics Data System (ADS)

    Yu, Xi

    Nanoparticles are regarded as exciting new building blocks for functional materials due to their fascinating physical properties because of the nano-confinement. Organizing nanoparticles into ordered hierarchical structures are highly desired for constructing novel optical and electrical artificial materials that are different from their isolated state or thermodynamics random ensembles. My research integrates the surface chemistry of nanoparticles, interfacial assembly and lithography techniques to construct nanoparticle based functional structures. We designed and synthesized tailor-made ligands for gold, semiconductor and magnetic nanoparticle, to modulate the assembly process and collective properties of the assembled structures, by controlling the key parameters such as particle-interface interaction, dielectric environments and inter-particle coupling etc. Top-down technologies such as micro contact printing, photolithography and nanoimprint lithography are used to guide the assembly into arbitrarily predesigned structures for potential device applications.

  14. Anticancer activity of Ficus religiosa engineered copper oxide nanoparticles.

    PubMed

    Sankar, Renu; Maheswari, Ramasamy; Karthik, Selvaraju; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

    2014-11-01

    The design, synthesis, characterization and application of biologically synthesized nanomaterials have become a vital branch of nanotechnology. There is a budding need to develop a method for environmentally benign metal nanoparticle synthesis, that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on an eco-friendly process for rapid synthesis of copper oxide nanoparticles using Ficus religiosa leaf extract as reducing and protecting agent. The synthesized copper oxide nanoparticles were confirmed by UV-vis spectrophotometer, absorbance peaks at 285 nm. The copper oxide nanoparticles were analyzed with field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD) spectrum. The FE-SEM and DLS analyses exposed that copper oxide nanoparticles are spherical in shape with an average particle size of 577 nm. FT-IR spectral analysis elucidates the occurrence of biomolecules required for the reduction of copper oxide ions. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The XRD pattern revealed that synthesized nanoparticles are crystalline in nature. Further, biological activities of the synthesized nanoparticles were confirmed based on its stable anti-cancer effects. The apoptotic effect of copper oxide nanoparticles is mediated by the generation of reactive oxygen species (ROS) involving the disruption of mitochondrial membrane potential (Δψm) in A549 cells. The observed characteristics and results obtained in our in vitro assays suggest that the copper nanoparticles might be a potential anticancer agent. PMID:25280701

  15. Potential for Inhalation Exposure to Engineered Nanoparticles from Nanotechnology-Based Cosmetic Powders

    PubMed Central

    Nazarenko, Yevgen; Zhen, Huajun; Han, Taewon; Lioy, Paul J.

    2012-01-01

    Background: The market of nanotechnology-based consumer products is rapidly expanding, and the lack of scientific evidence describing the accompanying exposure and health risks stalls the discussion regarding its guidance and regulation. Objectives: We investigated the potential for human contact and inhalation exposure to nanomaterials when using nanotechnology-based cosmetic powders and compare them with analogous products not marketed as nanotechnology based. Methods: We characterized the products using transmission electron microscopy (TEM) and laser diffraction spectroscopy and found nanoparticles in five of six tested products. TEM photomicrographs showed highly agglomerated states of nanoparticles in the products. We realistically simulated the use of cosmetic powders by applying them to the face of a human mannequin head while simultaneously sampling the released airborne particles through the ports installed in the mannequin’s nostrils. Results: We found that a user would be exposed to nanomaterial predominantly through nanoparticle-containing agglomerates larger than the 1–100-nm aerosol fraction. Conclusions: Predominant deposition of nanomaterial(s) will occur in the tracheobronchial and head airways—not in the alveolar region as would be expected based on the size of primary nanoparticles. This could potentially lead to different health effects than expected based on the current understanding of nanoparticle behavior and toxicology studies for the alveolar region. PMID:22394622

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

    PubMed Central

    Vodyanoy, Vitaly; Daniels, Yasmine; Pustovyy, Oleg; MacCrehan, William A; Muramoto, Shin; Stan, Gheorghe

    2016-01-01

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

  17. Engineering plasmon-enhanced Au light emission with planar arrays of nanoparticles.

    PubMed

    Walsh, Gary F; Dal Negro, Luca

    2013-02-13

    By systematically investigating the light emission and scattering properties of arrays of Au nanoparticles with varying size and separation, we demonstrate tunability and control of metal photoluminescence and unveil the critical role of near-field plasmonic coupling for the engineering of active metal nanostructures. We show that the decay of photoexcited electron-hole pairs into localized surface plasmons (LSPs) dramatically modifies the Au emission wavelength, line shape, and quantum efficiency depending both on particles size and separation. In particular, in arrays with near-field coupled nanoparticles we demonstrate broad light scattering and emission spectra that scale differently with respect to nanoparticle size due to the enhanced LSP nonradiative decay caused by near-field interparticle coupling. Our experimental results are fully supported by semianalytical extinction simulations based on rigorous coupled wave analysis, which demonstrate the importance of tuning plasmonic near-field coupling for the engineering of active devices based on light emitting arrays of metallic nanoparticles. PMID:23339774

  18. Compact, Engineered 2-Micron Coherent Doppler Wind Lidar Prototype for Field and Airborne Evaluation

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J.; Amzajerdian, Farzin; Koch, Grady J.

    2006-01-01

    The state-of-the-art 2-micron coherent Doppler wind lidar breadboard at NASA/LaRC will be engineered and compactly packaged consistent with future aircraft flights. The packaged transceiver will be integrated into a coherent Doppler wind lidar system test bed at LaRC. Atmospheric wind measurements will be made to validate the packaged technology. This will greatly advance the coherent part of the hybrid Doppler wind lidar solution to the need for global tropospheric wind measurements.

  19. Engineering the Structure and Properties of DNA-Nanoparticle Superstructures Using Polyvalent Counterions.

    PubMed

    Chou, Leo Y T; Song, Fayi; Chan, Warren C W

    2016-04-01

    DNA assembly of nanoparticles is a powerful approach to control their properties and prototype new materials. However, the structure and properties of DNA-assembled nanoparticles are labile and sensitive to interactions with counterions, which vary with processing and application environment. Here we show that substituting polyamines in place of elemental counterions significantly enhanced the structural rigidity and plasmonic properties of DNA-assembled metal nanoparticles. These effects arose from the ability of polyamines to condense DNA and cross-link DNA-coated nanoparticles. We further used polyamine wrapped DNA nanostructures as structural templates to seed the growth of polymer multilayers via layer-by-layer assembly, and controlled the degree of DNA condensation, plasmon coupling efficiency, and material responsiveness to environmental stimuli by varying polyelectrolyte composition. These results highlight counterion engineering as a versatile strategy to tailor the properties of DNA-nanoparticle assemblies for various applications, and should be applicable to other classes of DNA nanostructures. PMID:26942662

  20. Airborne multispectral and hyperspectral remote sensing: Examples of applications to the study of environmental and engineering problems

    SciTech Connect

    Bianchi, R.; Marino, C.M.

    1997-10-01

    The availability of a new aerial survey capability carried out by the CNR/LARA (National Research Council - Airborne Laboratory for the Environmental Research) by a new spectroradiometer AA5000 MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) on board a CASA 212/200 aircraft, enable the scientists to obtain innovative data sets, for different approach to the definitions and the understanding of a variety of environmental and engineering problems. The 102 MIVIS channels spectral bandwidths are chosen to meet the needs of scientific research for advanced applications of remote sensing data. In such configuration MIVIS can offer significant contributions to problem solving in wide sectors such as geologic exploration, agricultural crop studies, forestry, land use mapping, idrogeology, oceanography and others. LARA in 1994-96 has been active over different test-sites in joint-venture with JPL, Pasadena, different European Institutions and Italian University and Research Institutes. These aerial surveys allow the national and international scientific community to approach the use of Hyperspectral Remote Sensing in environmental problems of very large interest. The sites surveyed in Italy, France and Germany include a variety of targets such as quarries, landfills, karst cavities areas, landslides, coastlines, geothermal areas, etc. The deployments gathered up to now more than 300 GBytes of MIVIS data in more than 30 hours of VLDS data recording. The purpose of this work is to present and to comment the procedures and the results at research and at operational level of the past campaigns with special reference to the study of environmental and engineering problems.

  1. Vulnerability of drinking water supplies to engineered nanoparticles.

    PubMed

    Troester, Martin; Brauch, Heinz-Juergen; Hofmann, Thilo

    2016-06-01

    The production and use of engineered nanoparticles (ENPs) inevitably leads to their release into aquatic environments, with the quantities involved expected to increase significantly in the future. Concerns therefore arise over the possibility that ENPs might pose a threat to drinking water supplies. Investigations into the vulnerability of drinking water supplies to ENPs are hampered by the absence of suitable analytical methods that are capable of detecting and quantifiying ENPs in complex aqueous matrices. Analytical data concerning the presence of ENPs in drinking water supplies is therefore scarce. The eventual fate of ENPs in the natural environment and in processes that are important for drinking water production are currently being investigated through laboratory based-experiments and modelling. Although the information obtained from these studies may not, as yet, be sufficient to allow comprehensive assessment of the complete life-cycle of ENPs, it does provide a valuable starting point for predicting the significance of ENPs to drinking water supplies. This review therefore addresses the vulnerability of drinking water supplies to ENPs. The risk of ENPs entering drinking water is discussed and predicted for drinking water produced from groundwater and from surface water. Our evaluation is based on reviewing published data concerning ENP production amounts and release patterns, the occurrence and behavior of ENPs in aquatic systems relevant for drinking water supply and ENP removability in drinking water purification processes. Quantitative predictions are made based on realistic high-input case scenarios. The results of our synthesis of current knowledge suggest that the risk probability of ENPs being present in surface water resources is generally limited, but that particular local conditions may increase the probability of raw water contamination by ENPs. Drinking water extracted from porous media aquifers are not generally considered to be prone to ENP

  2. Recent prospective of surface engineered Nanoparticles in the management of Neurodegenerative disorders.

    PubMed

    Singh, Devendra; Kapahi, Himani; Rashid, Muzamil; Prakash, Atish; Majeed, Abu Bakar Abdul; Mishra, Neeraj

    2016-05-01

    Clinically, the therapeutic outcomes in neurodegenerative disorders (NDs) by drug treatment are very limited, and the most insurmountable obstacle in the treatment of NDs is the blood-brain barrier (BBB), which provides the highest level of protection from xenobiotics. A great deal of attention still needs to be paid to overcome these barriers, and surface-engineered polymeric nanoparticles are emerging as innovative tools that are able to interact with the biological system at a molecular level for the desired response. The present review covers the potential importance of surface-structure-engineered nanoparticles to overcome the BBB for good bioavailability, and the evaluation of drug therapy in NDs. PMID:26107112

  3. Cream Formulation Impact on Topical Administration of Engineered Colloidal Nanoparticles

    PubMed Central

    Marzi, Roberta; Cigni, Clara; Bedoni, Marzia; Gramatica, Furio; Palugan, Luca; Corsi, Fabio; Granucci, Francesca; Colombo, Miriam

    2015-01-01

    In order to minimize the impact of systemic toxicity of drugs in the treatment of local acute and chronic inflammatory reactions, the achievement of reliable and efficient delivery of therapeutics in/through the skin is highly recommended. While the use of nanoparticles is now an established practice for drug intravenous targeted delivery, their transdermal penetration is still poorly understood and this important administration route remains almost unexplored. In the present study, we have synthesized magnetic (iron oxide) nanoparticles (MNP) coated with an amphiphilic polymer, developed a water-in-oil emulsion formulation for their topical administration and compared the skin penetration routes with the same nanoparticles deposited as a colloidal suspension. Transmission and scanning electron microscopies provided ultrastructural evidence that the amphiphilic nanoparticles (PMNP) cream formulation allowed the efficient penetration through all the skin layers with a controllable kinetics compared to suspension formulation. In addition to the preferential follicular pathway, also the intracellular and intercellular routes were involved. PMNP that crossed all skin layers were quantified by inductively coupled plasma mass spectrometry. The obtained data suggests that combining PMNP amphiphilic character with cream formulation improves the intradermal penetration of nanoparticles. While PMNP administration in living mice via aqueous suspension resulted in preferential nanoparticle capture by phagocytes and migration to draining lymph nodes, cream formulation favored uptake by all the analyzed dermis cell types, including hematopoietic and non-hematopoietic. Unlike aqueous suspension, cream formulation also favored the maintenance of nanoparticles in the dermal architecture avoiding their dispersion and migration to draining lymph nodes via afferent lymphatics. PMID:25962161

  4. Cream formulation impact on topical administration of engineered colloidal nanoparticles.

    PubMed

    Santini, Benedetta; Zanoni, Ivan; Marzi, Roberta; Cigni, Clara; Bedoni, Marzia; Gramatica, Furio; Palugan, Luca; Corsi, Fabio; Granucci, Francesca; Colombo, Miriam

    2015-01-01

    In order to minimize the impact of systemic toxicity of drugs in the treatment of local acute and chronic inflammatory reactions, the achievement of reliable and efficient delivery of therapeutics in/through the skin is highly recommended. While the use of nanoparticles is now an established practice for drug intravenous targeted delivery, their transdermal penetration is still poorly understood and this important administration route remains almost unexplored. In the present study, we have synthesized magnetic (iron oxide) nanoparticles (MNP) coated with an amphiphilic polymer, developed a water-in-oil emulsion formulation for their topical administration and compared the skin penetration routes with the same nanoparticles deposited as a colloidal suspension. Transmission and scanning electron microscopies provided ultrastructural evidence that the amphiphilic nanoparticles (PMNP) cream formulation allowed the efficient penetration through all the skin layers with a controllable kinetics compared to suspension formulation. In addition to the preferential follicular pathway, also the intracellular and intercellular routes were involved. PMNP that crossed all skin layers were quantified by inductively coupled plasma mass spectrometry. The obtained data suggests that combining PMNP amphiphilic character with cream formulation improves the intradermal penetration of nanoparticles. While PMNP administration in living mice via aqueous suspension resulted in preferential nanoparticle capture by phagocytes and migration to draining lymph nodes, cream formulation favored uptake by all the analyzed dermis cell types, including hematopoietic and non-hematopoietic. Unlike aqueous suspension, cream formulation also favored the maintenance of nanoparticles in the dermal architecture avoiding their dispersion and migration to draining lymph nodes via afferent lymphatics. PMID:25962161

  5. Polymer coated gold nanoparticles for tracing the mobility of engineered nanoparticles in the subsurface

    NASA Astrophysics Data System (ADS)

    Uthuppu, Basil; Sidelmann Fjordbøge, Annika; Caspersen, Eva; Broholm, Mette Martina; Havsteen Jakobsen, Mogens

    2014-05-01

    Nanoparticles (NPs) are manufactured for their specific properties providing possibilities for new and improved products and applications. The use of engineered nanoparticles (ENPs) has therefore brought significant innovation and advances to society, including benefits for human health and the environment. At the same time, little is known about the potential risk associated with the inevitable release of these new materials to the environment, and their new properties are poorly understood . Suspensions of ENPs are not very stable, as they tend to aggregate thereby losing their properties as single particles. Coatings, including a large variety of natural and synthetic polymers, are used to enhance the colloid stability in high concentrations . However, increasing the stability of these materials may lead to unintended effects, such as enhancing their mobility in surface water and groundwater leading to inadvertent impacts on aquatic ecosystems and human health. Detection of ENPs in natural water systems, however, has proved very challenging. Hence, there is a need for tracing of ENP behaviour in the environment. We suggest a possibility of introducing inert gold NPs with the same mobility as the reactive NPs, as tracer particles. Colloidal gold has been of great interest for centuries due to its vibrant colors produced by the interaction with visible light. The unusual optical-electronic properties, high chemical stability and relatively low toxicity have made them the model system of choice in this context. Also, the natural occurrence of these particles in the proposed environment is very rare. Laboratory based experiments conducted in sand columns show that stable aqueous suspensions of gold NPs coated with amphiphilic block co polymers (PVP-VA and PVA-COOH) are extremely mobile (retardation factors of 1.0-1.2) with high recovery values (50-95 %). The specific retardation and recovery depends on the coating type, concentration and grafting method. The NPs

  6. Size Matters: Developing Design Rules to Engineer Nanoparticles for Solid Tumour Targeting

    NASA Astrophysics Data System (ADS)

    Sykes, Edward Alexander

    Nanotechnology enables the design of highly customizable platforms for producing minimally invasive and programmable strategies for cancer diagnosis and treatment. Advances in this field have demonstrated that nanoparticles can enhance specificity of anti-cancer agents, respond to tumour-specific cues, and direct the visualization of biological targets in vivo. . Nanoparticles can be synthesized within the 1 to 100 nm range to achieve different electromagnetic properties and specifically interact with biological tissues by tuning their size, shape, and surface chemistry. However, it remains unclear which physicochemical parameters are critical for delivering nanomaterials to the tumour site. With less than 5% of administered nanoparticles reaching the tumour, engineering of nanoparticles for effective delivery to solid tumours remains a critical challenge to cancer nanomedicine. A more comprehensive understanding of the interplay between the nanomaterial physicochemical properties and biological systems is necessary to enhance the efficacy of nanoparticle tumour targeting. This thesis explores how nanoparticle size and functionalization with cancer cell specific agents impact nanoparticle delivery to tumours. Furthermore, this doctoral work (i) discusses how tumour structure evolves with growth, (ii) elucidates how such changes modulate nanoparticle accumulation, and (iii) identifies how the skin serves as a significant off-target site for nanoparticle uptake. This thesis also demonstrates the utility of empirically-derived parametric models, Monte Carlo simulations, and decision matrices for mechanistically understanding and predicting the impact of nanomaterial features and tumour biology on nanoparticle fate in vivo. These topics establish key design considerations to tailor nanoparticles for enhanced tumour targeting. Collectively, the concepts presented herein form a fundamental framework for the development of personalized nanomedicine and nano

  7. Biocompatible nanotemplate-engineered nanoparticles containing gadolinium: stability and relaxivity of a potential MRI contrast agent.

    PubMed

    Zhu, Donghua; White, R D; Hardy, Peter A; Weerapreeyakul, Natthida; Sutthanut, Khaetthareeya; Jay, Michael

    2006-04-01

    In this article, we use a nanotemplate engineering approach to prepare biodegradable nanoparticles composed of FDA-approved materials and possessing accessible gadolinium (Gd) atoms and demonstrate their potential as a Magnetic Resonance Imaging (MRI) contrast agent. Nanoparticles containing dimyristoyl phosphoethanolamine diethylene triamine penta acetate (PE-DTPA) were prepared using 3.5 mg of Brij 78, 2.0 mg of emulsifying wax and 0.5 mg of PE-DTPA/ml from a microemulsion precursor. After the addition of GdCl3, the presence of Gd on the surface of nanoparticles was characterized using inductively coupled plasma atomic emission spectroscopy and Scanning Transmission Electron Microscopy (STEM). The in vitro relaxivities of the PE-DTPA-Gd nanoparticles in different media were assessed at different field strengths. The conditional stability constant of Gd binding to the nanoparticles was determined using competitive spectrophotometric titration. Transmetallation kinetics of the gadolinium ion from PE-DTPA-Gd nanoparticles with zinc as the competing ionic was measured using the relaxivity evolution method. Nanoparticles with a diameter of approximately 130 nm possessing surface chelating functions were made from GRAS (Generally Regarded As Safe) materials. STEM demonstrated the uniform distribution of Gd3+ on the surface of the nanoparticles. The thermodynamic binding constant for Gd3+ to the nanoparticles was approximately 10(18) M(-1) and transmetallation studies with Zn2+ yielded kinetic constants K1 and K(-1) of 0.033 and 0.022 1/h, respectively, with an equilibrium constant of 1.5. A payload of approximately 10(5) Gd/nanoparticle was achieved; enhanced relaxivities were observed, including a pH dependence of the transverse relaxivity (r2). Nanoparticles composed of materials that have been demonstrated to be hemocompatible and enzymatically metabolized and possessing accessible Gd ions on their surface induce relaxivities in the bulk water signal that make them

  8. Systems Engineering Management Plan NASA Traffic Aware Planner Integration Into P-180 Airborne Test-Bed

    NASA Technical Reports Server (NTRS)

    Maris, John

    2015-01-01

    NASA's Traffic Aware Planner (TAP) is a cockpit decision support tool that provides aircrew with vertical and lateral flight-path optimizations with the intent of achieving significant fuel and time savings, while automatically avoiding traffic, weather, and restricted airspace conflicts. A key step towards the maturation and deployment of TAP concerned its operational evaluation in a representative flight environment. This Systems Engineering Management Plan (SEMP) addresses the test-vehicle design, systems integration, and flight-test planning for the first TAP operational flight evaluations, which were successfully completed in November 2013. The trial outcomes are documented in the Traffic Aware Planner (TAP) flight evaluation paper presented at the 14th AIAA Aviation Technology, Integration, and Operations Conference, Atlanta, GA. (AIAA-2014-2166, Maris, J. M., Haynes, M. A., Wing, D. J., Burke, K. A., Henderson, J., & Woods, S. E., 2014).

  9. Engineered nanoparticles in wastewater and wastewater sludge - Evidence and impacts

    SciTech Connect

    Brar, Satinder K.; Verma, Mausam; Tyagi, R.D.; Surampalli, R.Y.

    2010-03-15

    Nanotechnology has widespread application in agricultural, environmental and industrial sectors ranging from fabrication of molecular assemblies to microbial array chips. Despite the booming application of nanotechnology, there have been serious implications which are coming into light in the recent years within different environmental compartments, namely air, water and soil and its likely impact on the human health. Health and environmental effects of common metals and materials are well-known, however, when the metals and materials take the form of nanoparticles - consequential hazards based on shape and size are yet to be explored. The nanoparticles released from different nanomaterials used in our household and industrial commodities find their way through waste disposal routes into the wastewater treatment facilities and end up in wastewater sludge. Further escape of these nanoparticles into the effluent will contaminate the aquatic and soil environment. Hence, an understanding of the presence, behavior and impact of these nanoparticles in wastewater and wastewater sludge is necessary and timely. Despite the lack of sufficient literature, the present review attempts to link various compartmentalization aspects of the nanoparticles, their physical properties and toxicity in wastewater and wastewater sludge through simile drawn from other environmental streams.

  10. Immunotoxicology of titanium dioxide and hydroxylated fullerenes engineered nanoparticles in fish models

    NASA Astrophysics Data System (ADS)

    Jovanovic, Boris

    2011-12-01

    Nanoparticles have the potential to cause adverse effects on the fish health, but the understanding of the underlying mechanisms is limited. Major task of this dissertation was to connect gaps in current knowledge with a comprehensive sequence of molecular, cellular and organismal responses toward environmentally relevant concentrations of engineered nanoparticles (titanium dioxide -- TiO2 and hydroxylated fullerenes), outlining the interaction with the innate immune system of fish. The research was divided into following steps: 1) create cDNA libraries for the species of fathead minnow (Pimephales promelas); 2) evaluate whether, and how can nanoparticles modulate neutrophil function in P. promelas; 3) determine the changes in expression of standard biomarker genes as a result of nanoparticle treatment; 4) expose the P. promelas to nanoparticles and appraise their survival rate in a bacterial challenge study; 5) assess the impact of nanoparticles on neuro-immunological interface during the early embryogenesis of zebrafish (Danio rerio). It was hypothesized that engineered nanoparticles can cause measurable changes in fish transcriptome, immune response, and disease resistance. The results of this dissertation are: 1) application of environmentally relevant concentration of nanoparticles changed function of fish neutrophils; 2) fish exposed to nano-TiO2 had significantly increased expression of interleukin 11, macrophage stimulating factor 1, and neutrophil cytosolic factor 2, while expression of interleukin 11 and myeloperoxidase was significantly increased and expression of elastase 2 was significantly decreased in fish exposed to hydroxylated fullerenes; 3) exposure to environmental estimated concentration of nano-TiO2 significantly increased fish mortality during Aeromonas hydrophila challenge. Analysis of nano-TiO 2 distribution in fish organism outlined that the nano-TiO2 is concentrating in the fish kidney and spleen; 4) during the early embryogenesis of D

  11. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air-liquid interface

    SciTech Connect

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2015-02-01

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specific fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. Together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.

  12. Airborne gravity is here

    SciTech Connect

    Hammer, S.

    1982-01-11

    After 20 years of development efforts, the airborne gravity survey has finally become a practical exploration method. Besides gravity data, the airborne survey can also collect simultaneous, continuous records of high-precision magneticfield data as well as terrain clearance; these provide a topographic contour map useful in calculating terrain conditions and in subsequent planning and engineering. Compared with a seismic survey, the airborne gravity method can cover the same area much more quickly and cheaply; a seismograph could then detail the interesting spots.

  13. Surface engineered gold nanoparticles through highly stable metal-surfactant complexes.

    PubMed

    Kim, Sunghwan; Jang, Youngjin; Yoon, Ki Youl; Park, Jongnam

    2016-02-15

    Monodispersed Au nanoparticles were synthesized by the reduction of Au-decyltrimethylammonium bromide (Au-DTAB), which was easily prepared via the reaction of HAuCl4 and DTAB. This Au-DTAB complex is highly stable in air and moisture, and suitable for large-scale synthesis of uniform-sized Au nanoparticles. The nanoparticles were characterized by transmission electron microscopy, optical absorption spectrometry, X-ray diffraction, and Fourier Transform infrared spectroscopy. The size of Au nanoparticles was controlled in the range of 5-10nm by changing the concentrations of reducing agent and Au precursor. The resulting Au nanoparticles were transferred to the aqueous phase after surface engineering using multidentate polymeric ligands with multiple imidazole functional groups. Polymeric imidazole ligands (PILs) demonstrated enhanced binding stability with the Au surface, and overcame the disadvantage of multidentate thiol ligand systems which have oxidative cross-linking and the formation of disulfide bonding. The colloidal stability of surface engineered Au nanoparticles with PILs was investigated by dynamic light scattering (DLS) characterization. PMID:26609930

  14. Controlled release of drugs in electrosprayed nanoparticles for bone tissue engineering.

    PubMed

    Jayaraman, Praveena; Gandhimathi, Chinnasamy; Venugopal, Jayarama Reddy; Becker, David Laurence; Ramakrishna, Seeram; Srinivasan, Dinesh Kumar

    2015-11-01

    Generating porous topographic substrates, by mimicking the native extracellular matrix (ECM) to promote the regeneration of damaged bone tissues, is a challenging process. Generally, scaffolds developed for bone tissue regeneration support bone cell growth and induce bone-forming cells by natural proteins and growth factors. Limitations are often associated with these approaches such as improper scaffold stability, and insufficient cell adhesion, proliferation, differentiation, and mineralization with less growth factor expression. Therefore, the use of engineered nanoparticles has been rapidly increasing in bone tissue engineering (BTE) applications. The electrospray technique is advantageous over other conventional methods as it generates nanomaterials of particle sizes in the micro/nanoscale range. The size and charge of the particles are controlled by regulating the polymer solution flow rate and electric voltage. The unique properties of nanoparticles such as large surface area-to-volume ratio, small size, and higher reactivity make them promising candidates in the field of biomedical engineering. These nanomaterials are extensively used as therapeutic agents and for drug delivery, mimicking ECM, and restoring and improving the functions of damaged organs. The controlled and sustained release of encapsulated drugs, proteins, vaccines, growth factors, cells, and nucleotides from nanoparticles has been well developed in nanomedicine. This review provides an insight into the preparation of nanoparticles by electrospraying technique and illustrates the use of nanoparticles in drug delivery for promoting bone tissue regeneration. PMID:26415888

  15. Engineered polymer nanoparticles containing hydrophobic dipeptide for inhibition of amyloid-β fibrillation.

    PubMed

    Skaat, Hadas; Chen, Ravit; Grinberg, Igor; Margel, Shlomo

    2012-09-10

    Protein aggregation into amyloid fibrils is implicated in the pathogenesis of many neurodegenerative diseases. Engineered nanoparticles have emerged as a potential approach to alter the kinetics of protein fibrillation process. Yet, there are only a few reports describing the use of nanoparticles for inhibition of amyloid-β 40 (Aβ(40)) peptide aggregation, involved in Alzheimer's disease (AD). In the present study, we designed new uniform biocompatible amino-acid-based polymer nanoparticles containing hydrophobic dipeptides in the polymer side chains. The dipeptide residues were designed similarly to the hydrophobic core sequence of Aβ. Poly(N-acryloyl-L-phenylalanyl-L-phenylalanine methyl ester) (polyA-FF-ME) nanoparticles of 57 ± 6 nm were synthesized by dispersion polymerization of the monomer A-FF-ME in 2-methoxy ethanol, followed by precipitation of the obtained polymer in aqueous solution. Cell viability assay confirmed that no significant cytotoxic effect of the polyA-FF-ME nanoparticles on different human cell lines, e.g., PC-12 and SH-SY5Y, was observed. A significantly slow secondary structure transition from random coil to β-sheets during Aβ(40) fibril formation was observed in the presence of these nanoparticles, resulting in significant inhibition of Aβ(40) fibrillation kinetics. However, the polyA-FF-ME analogous nanoparticles containing the L-alanyl-L-alanine (AA) dipeptide in the polymer side groups, polyA-AA-ME nanoparticles, accelerate the Aβ(40) fibrillation kinetics. The polyA-FF-ME nanoparticles and the polyA-AA-ME nanoparticles may therefore contribute to a mechanistic understanding of the fibrillation process, leading to the development of therapeutic strategies against amyloid-related diseases. PMID:22897679

  16. Transport of CO2 foam stabilized with engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Prigiobbe, V.; Worthen, A. J.; Aroonsri, A.; Huh, C.; Bryant, S. L.

    2014-12-01

    Foam injection into the subsurface is performed to improve gas control mobility for residual oil extraction in, e.g., enhanced oil recovery and contaminated site remediation. Foam improves the gas mobility control as the gas viscosity is increased through its dispersion into a liquid phase. Finer the bubbles the lower the gas apparent viscosity (or foam viscosity) and the better is the sweep efficiency of the residual oil. A chemical surfactant adsorbed at the gas-liquid interface is generally used to maintain an optimal foam texture (number of bubbles for unit volume) however it can be desorbed making the foam coarser. Here, we present an experimental and modeling study on the effect of nanoparticles on foam stability. Nanoparticles are adsorbed onto the bubble interface irreversibly and therefore they are expected to keep the desired texture of the foam for the entire time of its application. In this study, we use silica nanoparticles in conjunction with a surfactant to study the transport behavior of a CO2 foam in a porous medium. Experiments were performed using a glass-bead pack and Boise sandstone with foam quality (fg) 0.1-0.9 until steady-state. Foam flow was described by a mechanistic population balance model coupled with the fractional flow equation and constitutive equations for foam generation and destruction based on lamella division and bubble coalescence mechanisms, respectively. In order to minimize the uncertainty, model parameters were estimated by combining experimental data of pressure gradient during steady-state and transient. Experiments and theory agree very well and the overall results show a significant increase in foam texture and stability when nanoparticles and surfactant are added to a foam flow in a low permeability porous medium. Data from tests with various nanoparticle concentrations (cn) show that gas apparent viscosity changes with fg and cn. But its optimal value does not vary with cn and it is already attained at fg equal to 0

  17. Chitosan scaffolds containing chicken feather keratin nanoparticles for bone tissue engineering.

    PubMed

    Saravanan, S; Sameera, D K; Moorthi, A; Selvamurugan, N

    2013-11-01

    Chicken feathers are considered as major waste from poultry industry. They are mostly constituted by a protein called keratin. In this study, keratin was prepared from chicken feathers and from where keratin nanoparticles (nKer) were synthesized. Since chitosan has excellent properties like controlled biodegradation and biocompatibility, we used keratin nanoparticles along with chitosan matrix as scaffolds (CS/nKer) and they were characterized by SEM, FT-IR and XRD analyses. There was a porous architecture in the scaffolds in the range to support cell infiltration and tissue ingrowth. The keratin nanoparticles had interaction with chitosan matrix and did not alter the semi crystalline nature of chitosan scaffolds. The biodegradation and protein adsorption of the scaffolds were significantly increased upon addition of keratin nanoparticles. The scaffolds were also found to be non-cytotoxic to human osteoblastic cells. Thus, CS/nKer scaffolds could serve as a potential biomimetic substrate for bone tissue engineering applications. PMID:24095711

  18. Surface Engineering of Core/Shell Iron/Iron Oxide Nanoparticles from Microemulsions for Hyperthermia

    PubMed Central

    Zhang, Guandong; Liao, Yifeng; Baker, Ian

    2011-01-01

    This paper describes the synthesis and surface engineering of core/shell-type iron/iron oxide nanoparticles for magnetic hyperthermia cancer therapy. Iron/iron oxide nanoparticles were synthesized from microemulsions of NaBH4 and FeCl3, followed by surface modification in which a thin hydrophobic hexamethyldisilazane layer - used to protect the iron core - replaced the CTAB coating on the particles. Phosphatidylcholine was then assembled on the nanoparticle surface. The resulting nanocomposite particles have a biocompatible surface and show good stability in both air and aqueous solution. Compared to iron oxide nanoparticles, the nanocomposites show much better heating in an alternating magnetic field. They are good candidates for both hyperthermia and magnetic resonance imaging applications. PMID:21833157

  19. Radiation-Engineered Functional Nanoparticles in Aqueous Systems.

    PubMed

    Dispenza, Clelia; Grimaldi, Natascia; Sabatino, Maria Antonietta; Soroka, Inna L; Jonsson, Mats

    2015-05-01

    Controlled synthesis of nanoscalar and nanostructured materials enables the development of novel functional materials with fine-tuned optical, mechanical, electronic, magnetic, conductive and catalytic properties that are of use in numerous applications. These materials have also found their potential use in medicine as vehicles for drug delivery, in diagnostics or in combinations thereof. In principle, nanoparticles can be divided into two broad categories, organic and inorganic nanoparticles. For both types of nanoparticles there are numerous possible synthetic routes. Considering the large difference in nature of these materials and the elementary reactions involved in the synthetic routes, most manufacturing techniques are complex and only suitable for one type of particle. Interestingly, radiation chemistry, i.e., the use of ionizing radiation from radioisotopes and accelerators to induce nanomaterials or chemical changes in materials, has proven to be a versatile tool for controlled manufacturing of both organic and inorganic nanoparticles. The advantages of using radiation chemistry for this purpose are many, such as low energy consumption, minimal use of potentially harmful chemicals and simple production schemes. For medical applications one more advantage is that the material can be sterile as manufactured. Radiation-induced synthesis can be carried out in aqueous systems, which minimizes the use of organic solvents and the need for separation and purification of the final product. The radiation chemistry of water is well known, as are the various ways of fine-tuning the reactivity of the system towards a desired target by adding different solutes. This, in combination with the controllable and adjustable irradiation process parameters, makes the technique superior to most other chemical methods. In this review, we discuss the fundamentals of radiation chemistry and radiation-induced synthesis of nanoparticles in aqueous solutions. The impact of dose and

  20. Rational engineering of single-chain polypeptides into protein-only, BBB-targeted nanoparticles.

    PubMed

    Serna, Naroa; Céspedes, María Virtudes; Saccardo, Paolo; Xu, Zhikun; Unzueta, Ugutz; Álamo, Patricia; Pesarrodona, Mireia; Sánchez-Chardi, Alejandro; Roldán, Mónica; Mangues, Ramón; Vázquez, Esther; Villaverde, Antonio; Ferrer-Miralles, Neus

    2016-07-01

    A single chain polypeptide containing the low density lipoprotein receptor (LDLR) ligand Seq-1 with blood-brain barrier (BBB) crossing activity has been successfully modified by conventional genetic engineering to self-assemble into stable protein-only nanoparticles of 30nm. The nanoparticulate presentation dramatically enhances in vitro, LDLR-dependent cell penetrability compared to the parental monomeric version, but the assembled protein does not show any enhanced brain targeting upon systemic administration. While the presentation of protein drugs in form of nanoparticles is in general advantageous regarding correct biodistribution, this principle might not apply to brain targeting that is hampered by particular bio-physical barriers. Irrespective of this fact, which is highly relevant to the nanomedicine of central nervous system, engineering the cationic character of defined protein stretches is revealed here as a promising and generic approach to promote the controlled oligomerization of biologically active protein species as still functional, regular nanoparticles. PMID:26949165

  1. Modelling the transport of engineered metallic nanoparticles in the river Rhine.

    PubMed

    Markus, A A; Parsons, J R; Roex, E W M; de Voogt, P; Laane, R W P M

    2016-03-15

    As engineered nanoparticles of zinc oxide, titanium dioxide and silver, are increasingly used in consumer products, they will most probably enter the natural environment via wastewater, atmospheric deposition and other routes. The aim of this study is to predict the concentrations of these nanoparticles via wastewater emissions in a typical river system by means of a numerical model. The calculations rely on estimates of the use of nanomaterials in consumer products and the removal efficiency in wastewater treatment plants as well as model calculations of the fate and transport of nanoparticles in a riverine system. The river Rhine was chosen for this work as it is one of the major and best studied rivers in Europe. The study gives insight in the concentrations that can be expected and, by comparing the model results with measurements of the total metal concentrations, of the relative contribution of these emerging contaminants. Six scenarios were examined. Two scenarios concerned the total emission: in the first it was assumed that nanoparticles are only released via wastewater (treated or untreated) and in the second it was assumed that in addition nanoparticles can enter the river system via runoff from the application of sludge as a fertilizer. In both cases the assumption was that the nanoparticles enter the river system as free, unattached particles. Four additional scenarios, based on the total emissions from the second scenario, were examined to highlight the consequences of the assumption of free nanoparticles and the uncertainties about the aggregation processes. If all nanoparticles enter as free particles, roughly a third would end up attached to suspended particulate matter due to the aggregation processes nanoparticles are subject to. For the other scenarios the contribution varies from 20 to 45%. Since the Rhine is a fast flowing river, sedimentation is unlikely to occur, except at the floodplains and the lakes in the downstream regions, as in fact

  2. Laboratory Assessment of the Mobility of Water-Dispersed Engineered Nanoparticles in a Red Soil (Ultisol)

    EPA Science Inventory

    Soils are major sinks of engineered nanoparticles (ENPs) as results of land applications of sewage sludge, accidental spills, or deliberate applications of ENPs (e.g., nano-pesticides). In this study, the transport behaviors of four widely used ENPs (titanium dioxide [TiO2], buck...

  3. Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

    EPA Science Inventory

    CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

  4. Cutaneous exposure scenarios for engineered nanoparticles used in semiconductor fabrication: a preliminary investigation of workplace surface contamination

    PubMed Central

    Shepard, Michele; Brenner, Sara

    2014-01-01

    Background: Numerous studies are ongoing in the fields of nanotoxicology and exposure science; however, gaps remain in identifying and evaluating potential exposures from skin contact with engineered nanoparticles in occupational settings. Objectives: The aim of this study was to identify potential cutaneous exposure scenarios at a workplace using engineered nanoparticles (alumina, ceria, amorphous silica) and evaluate the presence of these materials on workplace surfaces. Methods: Process review, workplace observations, and preliminary surface sampling were conducted using microvacuum and wipe sample collection methods and transmission electron microscopy with elemental analysis. Results: Exposure scenarios were identified with potential for incidental contact. Nanoparticles of silica or silica and/or alumina agglomerates (or aggregates) were identified in surface samples from work areas where engineered nanoparticles were used or handled. Conclusions: Additional data are needed to evaluate occupational exposures from skin contact with engineered nanoparticles; precautionary measures should be used to minimize potential cutaneous exposures in the workplace. PMID:25000112

  5. Multigeometry Nanoparticle Engineering via Kinetic Control through Multistep assembly

    NASA Astrophysics Data System (ADS)

    Chen, Yingchao; Wang, Xiaojun; Zhang, Ke; Zhang, Fuwu; Mays, Jimmy; Wooley, Karen; Pochan, Darrin

    2014-03-01

    Organization of block copolymers into complicated multicompartment (MCM) and multigeometry (MGM) nanostructures is of increasing interest. Multistep, co-assembly methods resulting in kinetic control processing was used to produce complex nanoparticles that are not obtained via other assembly methods. Vesicle-cylinder, separate vesicle and cylinder, disk-cylinder, and mixed vesicle nanoparticles were constructed by binary blends of distinct diblock copolymers. Initially, the vesicle former polyacrylic acid-polyisoprene and cylinder former polyacrylic acid-polystyrene which share the same hydrophilic domain but immiscible hydrophobic domain were blended in THF. Secondly, dimaine molecules are added to associate with the common hydrophilic PAA. Importantly, and lastly, by tuning the kinetic addition rate of selective, miscible solvent water, the unlike hydrophobic blocks are kinetically trapped into one particle and eventually nanophase separate to form multiple compartments and multigeometries. The effective bottom-up multistep assembly strategies can be applied in other binary/ternary blends, in which new vesicle-sphere, disk-disk and cylinder-cylinder MCM/MGM nanoparticles were programed. We are grateful for the financial support from the National Science Funding DMR-0906815 (D.J.P. and K.L.W.) and NIST METROLOGY POCHAN 2012.

  6. Biopolymer-Based Nanoparticles for Drug/Gene Delivery and Tissue Engineering

    PubMed Central

    Nitta, Sachiko Kaihara; Numata, Keiji

    2013-01-01

    There has been a great interest in application of nanoparticles as biomaterials for delivery of therapeutic molecules such as drugs and genes, and for tissue engineering. In particular, biopolymers are suitable materials as nanoparticles for clinical application due to their versatile traits, including biocompatibility, biodegradability and low immunogenicity. Biopolymers are polymers that are produced from living organisms, which are classified in three groups: polysaccharides, proteins and nucleic acids. It is important to control particle size, charge, morphology of surface and release rate of loaded molecules to use biopolymer-based nanoparticles as drug/gene delivery carriers. To obtain a nano-carrier for therapeutic purposes, a variety of materials and preparation process has been attempted. This review focuses on fabrication of biocompatible nanoparticles consisting of biopolymers such as protein (silk, collagen, gelatin, β-casein, zein and albumin), protein-mimicked polypeptides and polysaccharides (chitosan, alginate, pullulan, starch and heparin). The effects of the nature of the materials and the fabrication process on the characteristics of the nanoparticles are described. In addition, their application as delivery carriers of therapeutic drugs and genes and biomaterials for tissue engineering are also reviewed. PMID:23344060

  7. CD44-engineered mesoporous silica nanoparticles for overcoming multidrug resistance in breast cancer

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Liu, Ying; Wang, Shouju; Shi, Donghong; Zhou, Xianguang; Wang, Chunyan; Wu, Jiang; Zeng, Zhiyong; Li, Yanjun; Sun, Jing; Wang, Jiandong; Zhang, Longjiang; Teng, Zhaogang; Lu, Guangming

    2015-03-01

    Multidrug resistance is a major impediment for the successful chemotherapy in breast cancer. CD44 is over-expressed in multidrug resistant human breast cancer cells. CD44 monoclonal antibody exhibits anticancer potential by inhibiting proliferation and regulating P-glycoprotein-mediated drug efflux activity in multidrug resistant cells. Thereby, CD44 monoclonal antibody in combination with chemotherapeutic drug might be result in enhancing chemosensitivity and overcoming multidrug resistance. The purpose of this study is to investigate the effects of the CD44 monoclonal antibody functionalized mesoporous silica nanoparticles containing doxorubicin on human breast resistant cancer MCF-7 cells. The data showed that CD44-modified mesoporous silica nanoparticles increased cytotoxicity and enhanced the downregulation of P-glycoprotein in comparison to CD44 antibody. Moreover, CD44-engineered mesoporous silica nanoparticles provided active target, which promoted more cellular uptake of DOX in the resistant cells and more retention of DOX in tumor tissues than unengineered counterpart. Animal studies of the resistant breast cancer xenografts demonstrated that CD44-engineered drug delivery system remarkably induced apoptosis and inhibited the tumor growth. Our results indicated that the CD44-engineered mesoporous silica nanoparticle-based drug delivery system offers an effective approach to overcome multidrug resistance in human breast cancer.

  8. Persistence of engineered nanoparticles in a municipal solid-waste incineration plant

    NASA Astrophysics Data System (ADS)

    Walser, Tobias; Limbach, Ludwig K.; Brogioli, Robert; Erismann, Esther; Flamigni, Luca; Hattendorf, Bodo; Juchli, Markus; Krumeich, Frank; Ludwig, Christian; Prikopsky, Karol; Rossier, Michael; Saner, Dominik; Sigg, Alfred; Hellweg, Stefanie; Günther, Detlef; Stark, Wendelin J.

    2012-08-01

    More than 100 million tonnes of municipal solid waste are incinerated worldwide every year. However, little is known about the fate of nanomaterials during incineration, even though the presence of engineered nanoparticles in waste is expected to grow. Here, we show that cerium oxide nanoparticles introduced into a full-scale waste incineration plant bind loosely to solid residues from the combustion process and can be efficiently removed from flue gas using current filter technology. The nanoparticles were introduced either directly onto the waste before incineration or into the gas stream exiting the furnace of an incinerator that processes 200,000 tonnes of waste per year. Nanoparticles that attached to the surface of the solid residues did not become a fixed part of the residues and did not demonstrate any physical or chemical changes. Our observations show that although it is possible to incinerate waste without releasing nanoparticles into the atmosphere, the residues to which they bind eventually end up in landfills or recovered raw materials, confirming that there is a clear environmental need to develop degradable nanoparticles.

  9. Persistence of engineered nanoparticles in a municipal solid-waste incineration plant.

    PubMed

    Walser, Tobias; Limbach, Ludwig K; Brogioli, Robert; Erismann, Esther; Flamigni, Luca; Hattendorf, Bodo; Juchli, Markus; Krumeich, Frank; Ludwig, Christian; Prikopsky, Karol; Rossier, Michael; Saner, Dominik; Sigg, Alfred; Hellweg, Stefanie; Günther, Detlef; Stark, Wendelin J

    2012-08-01

    More than 100 million tonnes of municipal solid waste are incinerated worldwide every year. However, little is known about the fate of nanomaterials during incineration, even though the presence of engineered nanoparticles in waste is expected to grow. Here, we show that cerium oxide nanoparticles introduced into a full-scale waste incineration plant bind loosely to solid residues from the combustion process and can be efficiently removed from flue gas using current filter technology. The nanoparticles were introduced either directly onto the waste before incineration or into the gas stream exiting the furnace of an incinerator that processes 200,000 tonnes of waste per year. Nanoparticles that attached to the surface of the solid residues did not become a fixed part of the residues and did not demonstrate any physical or chemical changes. Our observations show that although it is possible to incinerate waste without releasing nanoparticles into the atmosphere, the residues to which they bind eventually end up in landfills or recovered raw materials, confirming that there is a clear environmental need to develop degradable nanoparticles. PMID:22609690

  10. Performance of a scanning mobility particle sizer in measuring diverse types of airborne nanoparticles: Multi-walled carbon nanotubes, welding fumes, and titanium dioxide spray.

    PubMed

    Chen, Bean T; Schwegler-Berry, Diane; Cumpston, Amy; Cumpston, Jared; Friend, Sherri; Stone, Samuel; Keane, Michael

    2016-07-01

    Direct-reading instruments have been widely used for characterizing airborne nanoparticles in inhalation toxicology and industrial hygiene studies for exposure/risk assessments. Instruments using electrical mobility sizing followed by optical counting, e.g., scanning or sequential mobility particle spectrometers (SMPS), have been considered as the "gold standard" for characterizing nanoparticles. An SMPS has the advantage of rapid response and has been widely used, but there is little information on its performance in assessing the full spectrum of nanoparticles encountered in the workplace. In this study, an SMPS was evaluated for its effectiveness in producing "monodisperse" aerosol and its adequacy in characterizing overall particle size distribution using three test aerosols, each mimicking a unique class of real-life nanoparticles: singlets of nearly spherical titanium dioxide (TiO2), agglomerates of fiber-like multi-walled carbon nanotube (MWCNT), and aggregates that constitutes welding fume (WF). These aerosols were analyzed by SMPS, cascade impactor, and by counting and sizing of discrete particles by scanning and transmission electron microscopy. The effectiveness of the SMPS to produce classified particles (fixed voltage mode) was assessed by examination of the resulting geometric standard deviation (GSD) from the impactor measurement. Results indicated that SMPS performed reasonably well for TiO2 (GSD = 1.3), but not for MWCNT and WF as evidenced by the large GSD values of 1.8 and 1.5, respectively. For overall characterization, results from SMPS (scanning voltage mode) exhibited particle-dependent discrepancies in the size distribution and total number concentration compared to those from microscopic analysis. Further investigation showed that use of a single-stage impactor at the SMPS inlet could distort the size distribution and underestimate the concentration as shown by the SMPS, whereas the presence of vapor molecules or atom clusters in some test

  11. Performance of a Scanning Mobility Particle Sizer in Measuring Diverse Types of Airborne Nanoparticles: Multi-Walled Carbon Nanotubes, Welding Fumes, and Titanium Dioxide Spray

    PubMed Central

    Chen, Bean T.; Schwegler-Berry, Diane; Cumpston, Amy; Cumpston, Jared; Friend, Sherri; Stone, Samuel; Keane, Michael

    2016-01-01

    Direct-reading instruments have been widely used for characterizing airborne nanoparticles in inhalation toxicology and industrial hygiene studies for exposure/risk assessments. Instruments using electrical mobility sizing followed by optical counting, e.g., scanning or sequential mobility particle spectrometers (SMPS), have been considered as the “gold standard” for characterizing nanoparticles. An SMPS has the advantage of rapid response and has been widely used, but there is little information on its performance in assessing the full spectrum of nanoparticles encountered in the workplace. In this study, an SMPS was evaluated for its effectiveness in producing “monodisperse” aerosol and its adequacy in characterizing overall particle size distribution using three test aerosols, each mimicking a unique class of real-life nanoparticles: singlets of nearly spherical titanium dioxide (TiO2), agglomerates of fiber-like multi-walled carbon nanotube (MWCNT), and aggregates that constitutes welding fume (WF). These aerosols were analyzed by SMPS, cascade impactor, and by counting and sizing of discrete particles by scanning and transmission electron microscopy. The effectiveness of the SMPS to produce classified particles (fixed voltage mode) was assessed by examination of the resulting geometric standard deviation (GSD) from the impactor measurement. Results indicated that SMPS performed reasonably well for TiO2 (GSD = 1.3), but not for MWCNT and WF as evidenced by the large GSD values of 1.8 and 1.5, respectively. For overall characterization, results from SMPS (scanning voltage mode) exhibited particle-dependent discrepancies in the size distribution and total number concentration compared to those from microscopic analysis. Further investigation showed that use of a single-stage impactor at the SMPS inlet could distort the size distribution and underestimate the concentration as shown by the SMPS, whereas the presence of vapor molecules or atom clusters in

  12. Perspectives of Engineered Marine Derived Polymers for Biomedical Nanoparticles.

    PubMed

    Tran, Khanh Thi My; Vo, Toi Van; Duan, Wei; Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh

    2016-01-01

    Marine environment exhibits an enormous diversity of organisms which contains an abundant source of polysaccharides. As polymer matrix carriers, marine-based polymers possess several valuable properties including high stability, non-toxicity, hydrophilicity, biodegradability, with low production cost. Despite notable biological activities of these natural polymers, there are certain limitations in exploring their functions in applications of nano-sized drug delivery systems. The review aims to demonstrate exceptional characteristics of marine-based polymers including fucoidan, alginate, carrageenan, hyaluronic acid, chondroitin sulfate, and chitosan as well as provide perspectives of current publications on their nanoparticle formulations for biomedical applications. PMID:26898745

  13. Specific Internalisation of Gold Nanoparticles into Engineered Porous Protein Cages via Affinity Binding.

    PubMed

    Paramelle, David; Peng, Tao; Free, Paul; Fernig, David G; Lim, Sierin; Tomczak, Nikodem

    2016-01-01

    Porous protein cages are supramolecular protein self-assemblies presenting pores that allow the access of surrounding molecules and ions into their core in order to store and transport them in biological environments. Protein cages' pores are attractive channels for the internalisation of inorganic nanoparticles and an alternative for the preparation of hybrid bioinspired nanoparticles. However, strategies based on nanoparticle transport through the pores are largely unexplored, due to the difficulty of tailoring nanoparticles that have diameters commensurate with the pores size and simultaneously displaying specific affinity to the cages' core and low non-specific binding to the cages' outer surface. We evaluated the specific internalisation of single small gold nanoparticles, 3.9 nm in diameter, into porous protein cages via affinity binding. The E2 protein cage derived from the Geobacillus stearothermophilus presents 12 pores, 6 nm in diameter, and an empty core of 13 nm in diameter. We engineered the E2 protein by site-directed mutagenesis with oligohistidine sequences exposing them into the cage's core. Dynamic light scattering and electron microscopy analysis show that the structures of E2 protein cages mutated with bis- or penta-histidine sequences are well conserved. The surface of the gold nanoparticles was passivated with a self-assembled monolayer made of a mixture of short peptidols and thiolated alkane ethylene glycol ligands. Such monolayers are found to provide thin coatings preventing non-specific binding to proteins. Further functionalisation of the peptide coated gold nanoparticles with Ni2+ nitrilotriacetic moieties enabled the specific binding to oligohistidine tagged cages. The internalisation via affinity binding was evaluated by electron microscopy analysis. From the various mutations tested, only the penta-histidine mutated E2 protein cage showed repeatable and stable internalisation. The present work overcomes the limitations of currently

  14. Heteroaggregation of engineered nanoparticles and kaolin clays in aqueous environments.

    PubMed

    Wang, Hongtao; Dong, Ya-nan; Zhu, Miao; Li, Xiang; Keller, Arturo A; Wang, Tao; Li, Fengting

    2015-09-01

    The increasing and wide use of nanoparticles (NPs), including TiO2 and Ag NPs, have raised concerns due to their potential toxicity and environmental impacts. Kaolin is a very common mineral in aquatic systems, and there is a very high probability that nanoparticles (NPs) will interact with these clay minerals. We studied the effect of kaolin particles on the aggregation of NPs under different conditions, including the role of pH, ionic strength (IS), and humic acid (HA). We show that kaolin reduces the energy barrier and the Critical Coagulation Concentration (CCC) at pH 4. At pH 8, even though the energy barrier of the system without kaolin increases, kaolin promotes NP aggregation via heteroaggregation. When IS is equal to or greater than the CCC, on the one hand HA promotes aggregation of TiO2 NPs, but on the other hand HA decreases the rate of Ag NP aggregation because the existence of a surface coating may limit the adsorption of HA on these Ag NPs. In addition, the presence of HA increases the energy barrier and the CCC of the binary system (kaolin + NPs). Thus, the complex interactions of clay, NPs, IS, pH, and HA concentration determine the colloidal stability of the NPs. We find that kaolin is a potential coagulant for removal of NPs that behave like Ag and TiO2. PMID:26001279

  15. Engineering photonic-plasmonic coupling in metal nanoparticle necklaces.

    PubMed

    Pasquale, Alyssa J; Reinhard, Björn M; Dal Negro, Luca

    2011-08-23

    In this paper, by combining three-dimensional finite-difference time-domain simulations, dark-field scattering analysis, and surface-enhanced Raman spectroscopy (SERS) we systematically investigate the light-scattering and field localization properties of circular loops of closely spaced gold nanoparticles, or "nanoplasmonic necklaces", fabricated by electron-beam lithography on quartz substrates. In particular, we show that nanoplasmonic necklaces support two hybridized dipolar scattering resonances with polarization-controlled subwavelength localized fields (i.e., electromagnetic hot-spots), whose intensities are optimized by varying the necklace particle diameter and the particle number. Moreover, we show that strong field intensity enhancement is obtained for the particular necklace diameters where loop-localized photonic resonances efficiently couple to the broadband plasmonic modes, enabling a simple design strategy for the optimization of electromagnetic near-fields. Following the proposed approach, we design nanoplasmonic necklaces supporting stronger field intensity enhancement than traditional nanoparticle monomer and dimer arrays. Finally, by performing SERS experiments on nanoplasmonic necklaces coated with a pMA molecular monolayer, we validate the optimization of their near-field properties and demonstrate their potential for plasmon-enhanced spectroscopy and sensing. PMID:21739951

  16. Engineering empty space between Si nanoparticles for lithium-ion battery anodes.

    PubMed

    Wu, Hui; Zheng, Guangyuan; Liu, Nian; Carney, Thomas J; Yang, Yuan; Cui, Yi

    2012-02-01

    Silicon is a promising high-capacity anode material for lithium-ion batteries yet attaining long cycle life remains a significant challenge due to pulverization of the silicon and unstable solid-electrolyte interphase (SEI) formation during the electrochemical cycles. Despite significant advances in nanostructured Si electrodes, challenges including short cycle life and scalability hinder its widespread implementation. To address these challenges, we engineered an empty space between Si nanoparticles by encapsulating them in hollow carbon tubes. The synthesis process used low-cost Si nanoparticles and electrospinning methods, both of which can be easily scaled. The empty space around the Si nanoparticles allowed the electrode to successfully overcome these problems Our anode demonstrated a high gravimetric capacity (~1000 mAh/g based on the total mass) and long cycle life (200 cycles with 90% capacity retention). PMID:22224827

  17. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air–liquid interface

    DOE PAGESBeta

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica A.; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2013-12-02

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specificmore » fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. In conclusion, together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.« less

  18. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air–liquid interface

    SciTech Connect

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; Hu, Dehong; Szymanski, Craig J.; Tolic, Ana; Klein, Jessica A.; Smith, Jordan N.; Tarasevich, Barbara J.; Orr, Galya

    2013-12-02

    Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn2+) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn2+, together with organelle-specific fluorescent proteins, we quantified Zn2+ in single cells and organelles over time. We found that at the ALI, intracellular Zn2+ values peaked 3 h post exposure and decayed to normal values by 12 h, while in submersed cultures, intracellular Zn2+ values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn2+ values that were nearly 3 folds lower than the peak values generated by the lowest toxic dose of NPs in submersed cultures, and 8 folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn2+. At the ALI, the majority of intracellular Zn2+ was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn2+ following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. In conclusion, together, our observations indicate that low but critical levels of intracellular Zn2+ have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes

  19. Engineered nanoparticles mimicking cell membranes for toxin neutralization.

    PubMed

    Fang, Ronnie H; Luk, Brian T; Hu, Che-Ming J; Zhang, Liangfang

    2015-08-01

    Protein toxins secreted from pathogenic bacteria and venomous animals rely on multiple mechanisms to overcome the cell membrane barrier to inflict their virulence effect. A promising therapeutic concept toward developing a broadly applicable anti-toxin platform is to administer cell membrane mimics as decoys to sequester these virulence factors. As such, lipid membrane-based nanoparticulates are an ideal candidate given their structural similarity to cellular membranes. This article reviews the virulence mechanisms employed by toxins at the cell membrane interface and highlights the application of cell-membrane mimicking nanoparticles as toxin decoys for systemic detoxification. In addition, the implication of particle/toxin nanocomplexes in the development of toxoid vaccines is discussed. PMID:25868452

  20. Therapeutic cell engineering with surface-conjugated synthetic nanoparticles.

    PubMed

    Stephan, Matthias T; Moon, James J; Um, Soong Ho; Bershteyn, Anna; Irvine, Darrell J

    2010-09-01

    A major limitation of cell therapies is the rapid decline in viability and function of the transplanted cells. Here we describe a strategy to enhance cell therapy via the conjugation of adjuvant drug-loaded nanoparticles to the surfaces of therapeutic cells. With this method of providing sustained pseudoautocrine stimulation to donor cells, we elicited marked enhancements in tumor elimination in a model of adoptive T cell therapy for cancer. We also increased the in vivo repopulation rate of hematopoietic stem cell grafts with very low doses of adjuvant drugs that were ineffective when given systemically. This approach is a simple and generalizable strategy to augment cytoreagents while minimizing the systemic side effects of adjuvant drugs. In addition, these results suggest therapeutic cells are promising vectors for actively targeted drug delivery. PMID:20711198

  1. Modulation of Immune Response Using Engineered Nanoparticle Surfaces.

    PubMed

    Moyano, Daniel F; Liu, Yuanchang; Peer, Dan; Rotello, Vincent M

    2016-01-01

    Nanoparticles (NPs) coated with a monolayer of ligands can be recognized by different components of the immune system, opening new doors for the modulation of immunological responses. By the use of different physical or chemical properties at the NP surface (such as charge, functional groups, and ligand density), NPs can be designed to have distinct cellular uptake, cytokine secretion, and immunogenicity, factors that influence the distribution and clearance of these particles. Understanding these immunological responses is critical for the development of new NP-based carriers for the delivery of therapeutic molecules, and as such several studies have been performed to understand the relationships between immune responses and NP surface functionality. In this review, we will discuss recent reports of these structure-activity relationships, and explore how these motifs can be controlled to elicit therapeutically useful immune responses. PMID:26618755

  2. Embedded silica nanoparticles in poly(caprolactone) nanofibrous scaffolds enhanced osteogenic potential for bone tissue engineering.

    PubMed

    Ganesh, Nitya; Jayakumar, Rangasamy; Koyakutty, Manzoor; Mony, Ullas; Nair, Shantikumar V

    2012-09-01

    Poly(caprolactone) (PCL) has been frequently considered for bone tissue engineering because of its excellent biocompatibility. A drawback, however, of PCL is its inadequate mechanical strength for bone tissue engineering and its inadequate bioactivity to promote bone tissue regeneration from mesenchymal stem cells. To correct this deficiency, this work investigates the addition of nanoparticles of silica (nSiO(2)) to the scaffold to take advantage of the known bioactivity of silica as an osteogenic material and also to improve the mechanical properties through nanoscale reinforcement of the PCL fibers. The nanocomposite scaffolds and the pristine PCL scaffolds were evaluated physicochemically, mechanically, and biologically in the presence of human mesenchymal stem cells (hMSCs). The results indicated that, when the nanoparticles of size approximately 10 nm (concentrations of 0.5% and 1% w/v) were embedded within, or attached to, the PCL nanofibers, there was a substantial increase in scaffold strength, protein adsorption, and osteogenic differentiation of hMSCs. These nSiO(2) nanoparticles, when directly added to the cells evidently pointed to ingestion of these particles by the cells followed by cell death. The polymer nanofibers appeared to protect the cells by preventing ingestion of the silica nanoparticles, while at the same time adequately exposing them on fiber surfaces for their desired bioactivity. PMID:22725098

  3. Coiled fiber scaffolds embedded with gold nanoparticles improve the performance of engineered cardiac tissues

    NASA Astrophysics Data System (ADS)

    Fleischer, Sharon; Shevach, Michal; Feiner, Ron; Dvir, Tal

    2014-07-01

    Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold.Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00300d

  4. Engineering Gd-loaded nanoparticles to enhance MRI sensitivity via T1 shortening

    PubMed Central

    Bruckman, Michael A.; Yu, Xin; Steinmetz, Nicole F.

    2013-01-01

    Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining high-resolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity (R1), leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging. PMID:24158750

  5. Vehicle engines produce exhaust nanoparticles even when not fueled.

    PubMed

    Rönkkö, Topi; Pirjola, Liisa; Ntziachristos, Leonidas; Heikkilä, Juha; Karjalainen, Panu; Hillamo, Risto; Keskinen, Jorma

    2014-01-01

    Vehicle engines produce submicrometer exhaust particles affecting air quality, especially in urban environments. In on-road exhaust studies with a heavy duty diesel vehicle and in laboratory studies with two gasoline-fueled passenger cars, we found that as much as 20-30% of the number of exhaust particles larger than 3 nm may be formed during engine braking conditions-that is, during decelerations and downhill driving while the engine is not fueled. Particles appeared at size ranges extending even below 7 nm and at high number concentrations. Their small size and nonvolatility, coupled with the observation that these particles contain lube-oil-derived metals zinc, phosphorus, and calcium, are suggestive of health risks at least similar to those of exhaust particles observed before. The particles' characteristics indicate that their emissions can be reduced using exhaust after-treatment devices, although these devices have not been mandated for all relevant vehicle types. Altogether, our findings enhance the understanding of the formation vehicle emissions and allow for improved protection of human health in proximity to traffic. PMID:24397401

  6. Coiled fiber scaffolds embedded with gold nanoparticles improve the performance of engineered cardiac tissues.

    PubMed

    Fleischer, Sharon; Shevach, Michal; Feiner, Ron; Dvir, Tal

    2014-08-21

    Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold. PMID:24744098

  7. Zirconia-Nanoparticle-Reinforced Morphology-Engineered Graphene-Based Foams.

    PubMed

    Chakravarty, Dibyendu; Tiwary, Chandra Sekhar; Machado, Leonardo Dantas; Brunetto, Gustavo; Vinod, Soumya; Yadav, Ram Manohar; Galvao, Douglas S; Joshi, Shrikant V; Sundararajan, Govindan; Ajayan, Pulickel M

    2015-08-19

    The morphology of graphene-based foams can be engineered by reinforcing them with nanocrystalline zirconia, thus improving their oil-adsorption capacity; This can be observed experimentally and explained theoretically. Low zirconia fractions yield flaky microstructures where zirconia nanoparticles arrest propagating cracks. Higher zirconia concentrations possess a mesh-like interconnected structure where the degree of coiling is dependant on the local zirconia content. PMID:26171602

  8. Engineered gold nanoparticles for identification of novel ovarian biomarkers

    NASA Astrophysics Data System (ADS)

    Giri, Karuna

    Ovarian cancer is a leading cause of cancer related death among women in the US and worldwide. The disease has a high mortality rate due to limited tools available that can diagnose ovarian cancer at an early stage and the lack of effective treatments for disease free survival at late stages. Identification of proteins specifically expressed/overexpressed in ovarian cancer could lead to identification of novel diagnostic biomarkers and therapeutic targets that improve patient outcomes. In this regard, mass spectrometry is a powerful tool to probe the proteome of a cancer cell. It can aid discovery of proteins important for the pathophysiology of ovarian cancer. These proteins in turn could serve as diagnostic and treatment biomarkers of the disease. However, a limitation of mass spectrometry based proteomic analyses is that the technique lacks sensitivity and is biased against detection of low abundance proteins. With current approaches to biomarker discovery, we may therefore be overlooking candidate proteins that are important for ovarian cancer. This study presents a new approach to enrich low abundance proteins and subsequently detect them with mass spectrometry. Gold nanoparticles (AuNPs) and functionalization of their surfaces provide an excellent opportunity to capture and enrich low abundance proteins. First, the study focused on conducting an extensive investigation of the time evolution of nanoparticle-protein interaction and understanding drivers of protein attachment on nanoparticle surface. The adsorption of proteins to AuNPs was found to be highly dynamic with multiple attachment and detachment events which decreased over time. Initially, electrostatic forces played an important role in protein binding and structurally flexible proteins such as those involved in RNA processing were more likely to bind to AuNPs. More importantly, the feasibility and success of protein enrichment by AuNPs was evaluated. The AuNPs based approach was able to detect

  9. Behavior of engineered nanoparticles in aqueous solutions and porous media: Connecting experimentation to probabilistic analysis

    NASA Astrophysics Data System (ADS)

    Contreras, Carolina

    2011-12-01

    Engineered nanoparticles have enhanced products and services in the fields of medicine, energy, engineering, communications, personal care, environmental treatment, and many others. The increased use of engineered nanoparticles in consumer products will lead to these materials in natural systems, inevitably becoming a potential source of pollution. The study of the stability and mobility of these materials is fundamental to understand their behavior in natural systems and predict possible health and environmental implications. In addition, the use of probabilistic methods such as sensitivity analysis applied to the parameters controlling their behavior is useful in providing support in performing a risk assessment. This research investigated the stability and mobility of two types of metal oxide nanoparticles (aluminum oxide and titanium dioxide). The stability studies tested the effect of sand, pH 4, 7, and 10, and the NaCl in concentrations of 10mM, 25mM, 50mM, and 75mM. The mobility was tested using saturated quartz sand columns and nanoparticles suspension at pH 4 and 7 and in the presence of NaCl and CaCl2 in concentrations of 0.1mM, 1mM, and 10mM. Additionally, this work performed a sensitivity analysis of physical parameters used in mobility experiment performed for titanium dioxide and in mobility experiments taken from the literature for zero valent iron nanoparticles and fluorescent colloids to determine their effect on the value C/Co of by applying qualitative and quantitative methods. The results from the stability studies showed that titanium dioxide nanoparticles (TiO2) could remain suspended in solution for up to seven days at pH 10 and pH 7 even after settling of the sand; while for pH 4 solutions titanium settled along with the sand and after seven days no particles were observed in suspension. Other stability studies showed that nanoparticle aluminum oxide (Al2O3) and titanium dioxide (TiO2) size increased with increasing ionic strength (10 to 75

  10. Physicochemical comparison of commercially available metal oxide nanoparticles: implications for engineered nanoparticle toxicology and risk assessment

    EPA Science Inventory

    Accurate and affordable physicochemical characterization of commercial engineered nanomaterials is required for toxicology studies to ultimately determine nanomaterial: hazard identification; dose to response metric(s); and mechanism(s) of injury. A minimal physical and chemica...

  11. Lymphatic drug delivery using engineered liposomes and solid lipid nanoparticles

    PubMed Central

    Cai, Shuang; Zhang, Qiuhong; Bagby, Taryn; Forrest, M. Laird

    2011-01-01

    The lymphatic system plays a crucial role in the immune system’s recognition and response to disease, and most solid cancers initially spread from the primary site via the tumor’s surrounding lymphatics before hematological dissemination. Hence, the lymphatic system is an important target for developing new vaccines, cancer treatments, and diagnostic agents. Targeting the lymphatic system by subcutaneous, intestinal, and pulmonary routes has been evaluated and subsequently utilized to improve lymphatic penetration and retention of drug molecules, reduce drug-related systemic toxicities, and enhance bioavailability of poorly soluble and unstable drugs. Lymphatic imaging is an essential tool for the detection and staging of cancer. New nano-based technologies offer improved detection and characterization of the nodal diseases, while new delivery devices can better target and confine treatments to tumors within the nodal space while sparing healthy tissues. This manuscript reviews recent advances in the field of lymphatic drug delivery and imaging and focuses specifically on the development ofliposomes and solid lipid nanoparticles for lymphatic introduction via the subcutaneous, intestinal, and pulmonary routes. PMID:21712055

  12. Shape Engineering of Oxide Nanoparticles for Heterogeneous Catalysis.

    PubMed

    Zhou, Yan; Li, Yong; Shen, Wenjie

    2016-05-20

    The fabrication of oxide particles with tunable sizes and shapes at the nanoscale is one of the most crucial issues for the design and development of highly efficient heterogeneous catalysts. The shape of oxide nanoparticles has been demonstrated to affect their catalytic properties remarkably. Tuning the shape of oxide particles allows preferential exposure of specific reactive facets; this can maximize the number of active sites available to the reactants, which can improve the activity and also mediate the reaction route to a specific channel to achieve higher selectivity for a particular chemical reaction. In addition, the shape of the oxide particles affects their interaction with metal particles or clusters, and this involves interfacial strain and charge transfer. Metal particles or clusters dispersed on the reactive or polar facets of the oxide support often provide superior catalytic performance, primarily because of strong metal-support interactions. However, the geometric and electronic features of the metal-oxide interface may change during the course of the reaction, induced by chemisorption of reactive molecules at elevated temperatures, which should be taken into account in proposing a structure-reactivity relationship. PMID:26956929

  13. New Bismuth-Substituted Hydroxyapatite Nanoparticles for Bone Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Ciobanu, Gabriela; Bargan, Ana Maria; Luca, Constantin

    2015-11-01

    New bismuth-substituted hydroxyapatite [Ca10- x Bi x (PO4)6(OH)2 where x = 0-2.5] nanoparticles were synthesized by the co-precipitation method from aqueous solutions. The structural properties of the samples were analyzed by scanning electron microscopy coupled with x-ray analysis, x-ray powder diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface area analysis. The results confirm that bismuth ions have been incorporated into the hydroxyapatite lattice. The prepared nanocrystalline powders consisted of hydroxyapatite as single phase with hexagonal structure, crystal sizes smaller than 60 nm and (Bi + Ca)/P atomic ratio of around 1.67. The hydroxyapatite samples doped with Bi have mesoporous textures with pores size of around 2 nm and specific surface area in the range of 12-25 m2/g. The Bi-substituted hydroxyapatite powders are more effective against Gram-negative Escherichia coli bacteria than Gram-positive Staphylococcus aureus bacteria.

  14. Media ionic strength impacts embryonic responses to engineered nanoparticle exposure

    PubMed Central

    Truong, Lisa; Zaikova, Tatiana; Richman, Erik K.; Hutchison, James E.; Tanguay, Robert L.

    2012-01-01

    Embryonic zebrafish were used to assess the impact of solution ion concentrations on agglomeration and resulting in vivo biological responses of gold nanoparticles (AuNPs). The minimum ion concentration necessary to support embryonic development was determined. Surprisingly, zebrafish exhibit no adverse outcomes when raised in nearly ion-free media. During a rapid throughput screening of AuNPs, 1.2-nm 3-mercaptopropionic acid-functionalized AuNPs (1.2-nm 3-MPA-AuNPs) rapidly agglomerate in exposure solutions. When embryos were exposed to 1.2-nm 3-MPA-AuNPs dispersed in low ionic media, both morbidity and mortality were induced, but when suspended in high ionic media, there was little to no biological response. We demonstrated that the media ionic strength greatly affects agglomeration rates and biological responses. Most importantly, the insensitivity of the zebrafish embryo to external ions indicates that it is possible, and necessary, to adjust the exposure media conditions to optimize NP dispersion prior to assessment. PMID:21809903

  15. Modeling the transport of engineered nanoparticles in saturated porous media - an experimental setup

    NASA Astrophysics Data System (ADS)

    Braun, A.; Neukum, C.; Azzam, R.

    2011-12-01

    The accelerating production and application of engineered nanoparticles is causing concerns regarding their release and fate in the environment. For assessing the risk that is posed to drinking water resources it is important to understand the transport and retention mechanisms of engineered nanoparticles in soil and groundwater. In this study an experimental setup for analyzing the mobility of silver and titanium dioxide nanoparticles in saturated porous media is presented. Batch and column experiments with glass beads and two different soils as matrices are carried out under varied conditions to study the impact of electrolyte concentration and pore water velocities. The analysis of nanoparticles implies several challenges, such as the detection and characterization and the preparation of a well dispersed sample with defined properties, as nanoparticles tend to form agglomerates when suspended in an aqueous medium. The analytical part of the experiments is mainly undertaken with Flow Field-Flow Fractionation (FlFFF). This chromatography like technique separates a particulate sample according to size. It is coupled to a UV/Vis and a light scattering detector for analyzing concentration and size distribution of the sample. The advantage of this technique is the ability to analyze also complex environmental samples, such as the effluent of column experiments including soil components, and the gentle sample treatment. For optimization of the sample preparation and for getting a first idea of the aggregation behavior in soil solutions, in sedimentation experiments the effect of ionic strength, sample concentration and addition of a surfactant on particle or aggregate size and temporal dispersion stability was investigated. In general the samples are more stable the lower the concentration of particles is. For TiO2 nanoparticles, the addition of a surfactant yielded the most stable samples with smallest aggregate sizes. Furthermore the suspension stability is

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

    NASA Astrophysics Data System (ADS)

    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

  17. Engineering plasmonic nanoparticles for surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Pinkhasova, Polina

    This dissertation focuses on the development of novel nanotags encapsulated in an intricate Au-Ag nanostructure that uniquely functions both as a reporter and ultra-sensitive substrate for surface-enhanced Raman scattering (SERS) measurements. Hollow Au-Ag alloy nanoshells with a porous wall were synthesized by galvanic replacement reaction, and were subsequently loaded with Raman-active label molecules. The open structure of the nanoshells was filled with Ag via citrate reduction, entrapping label molecules in the process. The resultant nanotags have been shown to be individually SERS-active for the entrapped label molecules and robust for SERS measurements of analytes. We have shown that the SERS intensity of the molecular beacon is insensitive to environmental variants such as an external analyte 1,2-Di-(4-pyridyl)ethylene (BPE) and can be reliably used as an internal reference for quantitative measurements. Theoretical quantum chemical calculations and experimental studies revealed that surface-adsorbed poly(vinyl pyrrolidone) (PVP) used during nanotag formation which provides steric hindrance to promote colloidal stability actually enables highly selective SERS detection of analytes of various types and surface charge with enhancement factors as high as 108, depending on pH. Fully characterized nanotags were immobilized in the cladding air channels of suspended core photonic crystal fiber (PCF) to assess critical parameters such as nanoparticle coverage density and fiber length, both of which play an important role in the competitive interplay between accumulative Raman signal gain and attenuation loss, in order for the development of optimal SERS-active PCF optofluidic platform. We show that in the region where accumulative Raman gain dominates, the length of PCF can be exploited for enhanced measurement sensitivity.

  18. Supercritical Fluid Synthesis and Tribological Applications of Silver Nanoparticle-decorated Graphene in Engine Oil Nanofluid

    NASA Astrophysics Data System (ADS)

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-08-01

    Silver nanoparticle-decorated graphene nanocomposites were synthesized by a facile chemical reduction approach with the assistance of supercritical CO2 (ScCO2). The silver nanoparticles with diameters of 2–16 nm are uniformly distributed and firmly anchored on graphene nanosheets. The tribological properties of the as-synthesized nanocomposites as lubricant additives in engine oil were investigated by a four-ball tribometer. The engine oil with 0.06~0.10 wt.% Sc-Ag/GN nanocomposites displays remarkable lubricating performance, superior than the pure engine oil, the engine oil containing zinc dialkyl dithiophosphate (ZDDP), as well as the oil dispersed with the single nanomaterial of graphene oxides (GOs) and nano-Ag particles alone. The remarkable lubricating behaviors of Sc-Ag/GN probably derive from the synergistic interactions of nano-Ag and graphene in the nanocomposite and the action of the formed protective film on the contact balls. The anchored nano-Ag particles on graphene expand the interlamination spaces of graphene nanosheets and can prevent them from restacking during the rubbing process, resulting in the full play of lubricating activity of graphene. The formed protective film on the friction pairs significantly reduces the surface roughness of the sliding balls and hence preventing them from direct interaction during the sliding process.

  19. Supercritical Fluid Synthesis and Tribological Applications of Silver Nanoparticle-decorated Graphene in Engine Oil Nanofluid

    PubMed Central

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-01-01

    Silver nanoparticle-decorated graphene nanocomposites were synthesized by a facile chemical reduction approach with the assistance of supercritical CO2 (ScCO2). The silver nanoparticles with diameters of 2–16 nm are uniformly distributed and firmly anchored on graphene nanosheets. The tribological properties of the as-synthesized nanocomposites as lubricant additives in engine oil were investigated by a four-ball tribometer. The engine oil with 0.06~0.10 wt.% Sc-Ag/GN nanocomposites displays remarkable lubricating performance, superior than the pure engine oil, the engine oil containing zinc dialkyl dithiophosphate (ZDDP), as well as the oil dispersed with the single nanomaterial of graphene oxides (GOs) and nano-Ag particles alone. The remarkable lubricating behaviors of Sc-Ag/GN probably derive from the synergistic interactions of nano-Ag and graphene in the nanocomposite and the action of the formed protective film on the contact balls. The anchored nano-Ag particles on graphene expand the interlamination spaces of graphene nanosheets and can prevent them from restacking during the rubbing process, resulting in the full play of lubricating activity of graphene. The formed protective film on the friction pairs significantly reduces the surface roughness of the sliding balls and hence preventing them from direct interaction during the sliding process. PMID:27488733

  20. Supercritical Fluid Synthesis and Tribological Applications of Silver Nanoparticle-decorated Graphene in Engine Oil Nanofluid.

    PubMed

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-01-01

    Silver nanoparticle-decorated graphene nanocomposites were synthesized by a facile chemical reduction approach with the assistance of supercritical CO2 (ScCO2). The silver nanoparticles with diameters of 2-16 nm are uniformly distributed and firmly anchored on graphene nanosheets. The tribological properties of the as-synthesized nanocomposites as lubricant additives in engine oil were investigated by a four-ball tribometer. The engine oil with 0.06~0.10 wt.% Sc-Ag/GN nanocomposites displays remarkable lubricating performance, superior than the pure engine oil, the engine oil containing zinc dialkyl dithiophosphate (ZDDP), as well as the oil dispersed with the single nanomaterial of graphene oxides (GOs) and nano-Ag particles alone. The remarkable lubricating behaviors of Sc-Ag/GN probably derive from the synergistic interactions of nano-Ag and graphene in the nanocomposite and the action of the formed protective film on the contact balls. The anchored nano-Ag particles on graphene expand the interlamination spaces of graphene nanosheets and can prevent them from restacking during the rubbing process, resulting in the full play of lubricating activity of graphene. The formed protective film on the friction pairs significantly reduces the surface roughness of the sliding balls and hence preventing them from direct interaction during the sliding process. PMID:27488733

  1. Intracellular Uptake: A Possible Mechanism for Silver Engineered Nanoparticle Toxicity to a Freshwater Alga Ochromonas danica

    PubMed Central

    Miao, Ai-Jun; Luo, Zhiping; Chen, Chi-Shuo; Chin, Wei-Chun; Santschi, Peter H.; Quigg, Antonietta

    2010-01-01

    The behavior and toxicity of silver engineered nanoparticles (Ag-ENs) to the mixotrophic freshwater alga Ochromonas danica were examined in the present study to determine whether any other mechanisms are involved in their algal toxicity besides Ag+ liberation outside the cells. Despite their good dispersability, the Ag-ENs were found to continuously aggregate and dissolve rapidly. When the initial nanoparticle concentration was lower than 10 µM, the total dissolved Ag+ concentration ([Ag+]T) in the suspending media reached its maximum after 1 d and then decreased suggesting that Ag+ release might be limited by the nanoparticle surface area under these conditions. Furthermore, Ag-EN dissolution extent remarkably increased in the presence of glutathione. In the Ag-EN toxicity experiment, glutathione was also used to eliminate the indirect effects of Ag+ that was released. However, remarkable toxicity was still observed although the free Ag+ concentration in the media was orders of magnitude lower than the non-observed effect concentration of Ag+ itself. Such inhibitive effects were mitigated when more glutathione was added, but could never be completely eliminated. Most importantly, we demonstrate, for the first time, that Ag-ENs can be taken in and accumulated inside the algal cells, where they exerted their toxic effects. Therefore, nanoparticle internalization may be an alternative pathway through which algal growth can be influenced. PMID:21203552

  2. Shape-Engineered multifunctional porous silicon nanoparticles by direct imprinting

    NASA Astrophysics Data System (ADS)

    Mares, Jeremy W.; Fain, Joshua S.; Beavers, Kelsey R.; Duvall, Craig L.; Weiss, Sharon M.

    2015-07-01

    A versatile and scalable method for fabricating shape-engineered nano- and micrometer scale particles from mesoporous silicon (PSi) thin films is presented. This approach, based on the direct imprinting of porous substrates (DIPS) technique, facilitates the generation of particles with arbitrary shape, ranging in minimum dimension from approximately 100 nm to several micrometers, by carrying out high-pressure (>200 MPa) direct imprintation, followed by electrochemical etching of a sub-surface perforation layer and ultrasonication. PSi particles (PSPs) with a variety of geometries have been produced in quantities sufficient for biomedical applications (≫10 μg). Because the stamps can be reused over 150 times, this process is substantially more economical and efficient than the use of electron beam lithography and reactive ion etching for the fabrication of nanometer-scale PSPs directly. The versatility of this fabrication method is demonstrated by loading the DIPS-imprinted PSPs with a therapeutic peptide nucleic acid drug molecule, and by vapor deposition of an Au coating to facilitate the use of PSPs as a photothermal contrast agent.

  3. Shape-engineered multifunctional porous silicon nanoparticles by direct imprinting.

    PubMed

    Mares, Jeremy W; Fain, Joshua S; Beavers, Kelsey R; Duvall, Craig L; Weiss, Sharon M

    2015-07-10

    A versatile and scalable method for fabricating shape-engineered nano- and micrometer scale particles from mesoporous silicon (PSi) thin films is presented. This approach, based on the direct imprinting of porous substrates (DIPS) technique, facilitates the generation of particles with arbitrary shape, ranging in minimum dimension from approximately 100 nm to several micrometers, by carrying out high-pressure (>200 MPa) direct imprintation, followed by electrochemical etching of a sub-surface perforation layer and ultrasonication. PSi particles (PSPs) with a variety of geometries have been produced in quantities sufficient for biomedical applications (≫10 μg). Because the stamps can be reused over 150 times, this process is substantially more economical and efficient than the use of electron beam lithography and reactive ion etching for the fabrication of nanometer-scale PSPs directly. The versatility of this fabrication method is demonstrated by loading the DIPS-imprinted PSPs with a therapeutic peptide nucleic acid drug molecule, and by vapor deposition of an Au coating to facilitate the use of PSPs as a photothermal contrast agent. PMID:26081802

  4. Functional enhancement of chitosan and nanoparticles in cell culture, tissue engineering, and pharmaceutical applications

    PubMed Central

    Gao, Wenjuan; Lai, James C. K.; Leung, Solomon W.

    2012-01-01

    As a biomaterial, chitosan has been widely used in tissue engineering, wound healing, drug delivery, and other biomedical applications. It can be formulated in a variety of forms, such as powder, film, sphere, gel, and fiber. These features make chitosan an almost ideal biomaterial in cell culture applications, and cell cultures arguably constitute the most practical way to evaluate biocompatibility and biotoxicity. The advantages of cell cultures are that they can be performed under totally controlled environments, allow high throughput functional screening, and are less costly, as compared to other assessment methods. Chitosan can also be modified into multilayer composite by combining with other polymers and moieties to alter the properties of chitosan for particular biomedical applications. This review briefly depicts and discusses applications of chitosan and nanoparticles in cell culture, in particular, the effects of chitosan and nanoparticles on cell adhesion, cell survival, and the underlying molecular mechanisms: both stimulatory and inhibitory influences are discussed. Our aim is to update the current status of how nanoparticles can be utilized to modify the properties of chitosan to advance the art of tissue engineering by using cell cultures. PMID:22934070

  5. Chitosan-based nanoparticles as a sustained protein release carrier for tissue engineering applications.

    PubMed

    Hou, Yaping; Hu, Junli; Park, Hyejin; Lee, Min

    2012-04-01

    Chitosan/tripolyphosphate/chondroitin sulfate (Chi/TPP/CS) nanoparticles were prepared by an ionic gelation method to obtain a controlled release of proteins. Using Nel-like molecule-1 (Nell-1), a novel osteogenic protein, as a model protein, it was demonstrated that adjusting the composition of the particles modulated the protein association and release kinetics of incorporated proteins. Increasing the amounts of Chi crosslinking agents, TPP and CS, in the particles achieved sustained protein release. An increase in crosslinking density decreased degradation rates of the particles. Furthermore, the bioactivity of the protein was preserved during the encapsulating procedure into the particles. To demonstrate the feasibility of Chi/TPP/CS nanoparticles as sustained release carriers for tissue engineering scaffold applications, protein-loaded nanoparticles were successfully incorporated into collagen hydrogels or prefabricated porous poly(lactide-co-glycolide) (PLGA) scaffolds without obstructing the integrity of the hydrogels or porous structure of the scaffolds. Thus, we expect that these particles have a potential for efficient protein carriers in tissue engineering applications, and will be further evaluated in vivo. PMID:22275184

  6. Chemical analysis of diesel engine nanoparticles using a nano-DMA/thermal desorption particle beam mass spectrometer.

    PubMed

    Tobias, H J; Beving, D E; Ziemann, P J; Sakurai, H; Zuk, M; McMurry, P H; Zarling, D; Waytulonis, R; Kittelson, D B

    2001-06-01

    Diesel engines are known to emit high number concentrations of nanoparticles (diameter < 50 nm), but the physical and chemical mechanisms by which they form are not understood. Information on chemical composition is lacking because the small size, low mass concentration, and potential for contamination of samples obtained by standard techniques make nanoparticles difficult to analyze. A nano-differential mobility analyzer was used to size-select nanoparticles (mass median diameter approximately 25-60 nm) from diesel engine exhaust for subsequent chemical analysis by thermal desorption particle beam mass spectrometry. Mass spectra were used to identify and quantify nanoparticle components, and compound molecular weights and vapor pressures were estimated from calibrated desorption temperatures. Branched alkanes and alkyl-substituted cycloalkanes from unburned fuel and/or lubricating oil appear to contribute most of the diesel nanoparticle mass. The volatility of the organic fraction of the aerosol increases as the engine load decreases and as particle size increases. Sulfuric acid was also detected at estimated concentrations of a few percent of the total nanoparticle mass. The results are consistent with a mechanism of nanoparticle formation involving nucleation of sulfuric acid and water, followed by particle growth by condensation of organic species. PMID:11414024

  7. Engineering the defect state and reducibility of ceria based nanoparticles for improved anti-oxidation performance

    NASA Astrophysics Data System (ADS)

    Wang, Yan-Jie; Dong, Hao; Lyu, Guang-Ming; Zhang, Huai-Yuan; Ke, Jun; Kang, Li-Qun; Teng, Jia-Li; Sun, Ling-Dong; Si, Rui; Zhang, Jing; Liu, Yan-Jun; Zhang, Ya-Wen; Huang, Yun-Hui; Yan, Chun-Hua

    2015-08-01

    Due to their excellent anti-oxidation performance, CeO2 nanoparticles receive wide attention in pharmacological application. Deep understanding of the anti-oxidation mechanism of CeO2 nanoparticles is extremely important to develop potent CeO2 nanomaterials for anti-oxidation application. Here, we report a detailed study on the anti-oxidation process of CeO2 nanoparticles. The valence state and coordination structure of Ce are characterized before and after the addition of H2O2 to understand the anti-oxidation mechanism of CeO2 nanoparticles. Adsorbed peroxide species are detected during the anti-oxidation process, which are responsible for the red-shifted UV-vis absorption spectra of CeO2 nanoparticles. Furthermore, the coordination number of Ce in the first coordination shell slightly increased after the addition of H2O2. On the basis of these experimental results, the reactivity of coordination sites for peroxide species is considered to play a key role in the anti-oxidation performance of CeO2 nanoparticles. Furthermore, we present a robust method to engineer the anti-oxidation performance of CeO2 nanoparticles through the modification of the defect state and reducibility by doping with Gd3+. Improved anti-oxidation performance is also observed in cell culture, where the biocompatible CeO2-based nanoparticles can protect INS-1 cells from oxidative stress induced by H2O2, suggesting the potential application of CeO2 nanoparticles in the treatment of diabetes.Due to their excellent anti-oxidation performance, CeO2 nanoparticles receive wide attention in pharmacological application. Deep understanding of the anti-oxidation mechanism of CeO2 nanoparticles is extremely important to develop potent CeO2 nanomaterials for anti-oxidation application. Here, we report a detailed study on the anti-oxidation process of CeO2 nanoparticles. The valence state and coordination structure of Ce are characterized before and after the addition of H2O2 to understand the anti

  8. Engineering an artificial amoeba propelled by nanoparticle-triggered actin polymerization.

    PubMed

    Yi, Jinsoo; Schmidt, Jacob; Chien, Aichi; Montemagno, Carlo D

    2009-02-25

    We have engineered an amoeba system combining nanofabricated inorganic materials with biological components, capable of propelling itself via actin polymerization. The nanofabricated materials have a mechanism similar to the locomotion of the Listeria monocytogenes, food poisoning bacteria. The propulsive force generation utilizes nanoparticles made from nickel and gold functionalized with the Listeria monocytogenes transmembrane protein, ActA. These Listeria-mimic nanoparticles were in concert with actin, actin binding proteins, ATP (adenosine triphosphate) and encapsulated within a lipid vesicle. This system is an artificial cell, such as a vesicle, where artificial nanobacteria and actin polymerization machinery are used in driving force generators inside the cell. The assembled structure was observed to crawl on a glass surface analogously to an amoeba, with the speed of the movement dependent on the amount of actin monomers and ATP present. PMID:19417437

  9. Engineering an artificial amoeba propelled by nanoparticle-triggered actin polymerization

    NASA Astrophysics Data System (ADS)

    Yi, Jinsoo; Schmidt, Jacob; Chien, Aichi; Montemagno, Carlo D.

    2009-02-01

    We have engineered an amoeba system combining nanofabricated inorganic materials with biological components, capable of propelling itself via actin polymerization. The nanofabricated materials have a mechanism similar to the locomotion of the Listeria monocytogenes, food poisoning bacteria. The propulsive force generation utilizes nanoparticles made from nickel and gold functionalized with the Listeria monocytogenes transmembrane protein, ActA. These Listeria-mimic nanoparticles were in concert with actin, actin binding proteins, ATP (adenosine triphosphate) and encapsulated within a lipid vesicle. This system is an artificial cell, such as a vesicle, where artificial nanobacteria and actin polymerization machinery are used in driving force generators inside the cell. The assembled structure was observed to crawl on a glass surface analogously to an amoeba, with the speed of the movement dependent on the amount of actin monomers and ATP present.

  10. Fabrication of hydrogel based nanocomposite scaffold containing bioactive glass nanoparticles for myocardial tissue engineering.

    PubMed

    Barabadi, Zahra; Azami, Mahmoud; Sharifi, Esmaeel; Karimi, Roya; Lotfibakhshaiesh, Nasrin; Roozafzoon, Reza; Joghataei, Mohammad Taghi; Ai, Jafar

    2016-12-01

    Selecting suitable cell sources and angiogenesis induction are two important issues in myocardial tissue engineering. Human endometrial stromal cells (EnSCs) have been introduced as an abundant and easily available resource in regenerative medicine. Bioactive glass is an agent that induces angiogenesis and has been studied in some experiments. The aim of this study was to investigate in vitro differentiation capacity of endometrial stem cells into cardiomyocyte lineage and to evaluate capability of bioactive glass nanoparticles toward EnSCs differentiation into endothelial lineage and angiogenesis on hydrogel scaffold. Our findings suggests that endometrial stem cells could be programmed into cardiomyocyte linage and considered a suitable cell source for myocardial regeneration. This experiment also revealed that inclusion of bioactive glass nanoparticles in hydrogel scaffold could improve angiogenesis through differentiating EnSCs toward endothelial lineage and increasing level of vascular endothelial growth factor secretion. PMID:27612811

  11. The many faces of soot: characterization of soot nanoparticles produced by engines.

    PubMed

    Niessner, Reinhard

    2014-11-10

    Soot nanoparticles produced by engines constitute a threat to human health. For the analytical chemist, soot is a hard nut to crack as the released particles undergo rapid changes in their size, shape, and number concentration. The complete characterization of soot will be essential to meet future low-emission standards. Besides measuring the light extinction, modern analytical chemistry can determine a variety of less-known effects, such as condensation properties, immune response in vertebrates, and impact on the cardiovascular function of a beating heart. Photon emission and in particular Raman spectroscopy provides information on the nanocrystallinity, while thermoelectron emission allows the number of electrical particles to be counted. Even the "simple" combustion of soot nanoparticles offers potential for the characterization of the particles. PMID:25196472

  12. Aggregation behavior of engineered nanoparticles and their impact on activated sludge in wastewater treatment.

    PubMed

    Zhou, Xiao-hong; Huang, Bao-cheng; Zhou, Tao; Liu, Yan-chen; Shi, Han-chang

    2015-01-01

    The ever-increasing daily use of engineered nanoparticles will lead to heightened levels of these materials in the environment. These nanomaterials will eventually go into the wastewater treatment plant (WWTP), therefore, resulting into a pressing need for information on their aggregation behavior and kinetics in the wastewater aqueous matrix. In this work, we dispersed two different metal oxide nanoparticles (ZnO and TiO2) into the influent of two different WWTPs. Through the time-resolved dynamic light scattering analysis and transmission electron microscopy, the metal oxide nanoparticles (NPs) were quite stably existed in the wastewater matrix with aggregates of diameter 300-400 nm after 4.5h or more suspension. We confirmed that the dissolved organic matters (DOMs) attributed to the stability of nanoparticles. No propensity of NPs to aggregate were observed in the presence of both monovalent and divalent electrolytes even at high concentrations up to 0.15 M in NaCl or 0.025 M in CaCl2, indicating that the destabilization of nanoparticles in the complicated wastewater matrix was not achieved by the compression of electrical double layer, therefore, their aggregation kinetics cannot be simply predicted by the classic Derjaguin-Landau-Verwey-Overbeek theory of colloidal stability. However, obvious aggregation of nanoparticles in the Al2(SO4)3 solution system was observed with the likely mechanism of bridging of the metal oxide nanoparticles and aggregates due to the formation of hydrous alumina (Al(OH)3·H2O) in the Al2(SO4)3 solution. In the wastewater matrix, we used the noninvasive measurement technology to detect the O2 flux of activated sludge before and after treatment with 1, 10 and 100 mg L(-1) NPs. The results confirmed that both ZnO and TiO2 NPs showed an adverse impact on the O2 uptake of activated sludge when the exposure time extended to 4.5 h. PMID:25127355

  13. Potent Engineered PLGA Nanoparticles by Virtue of Exceptionally High Chemotherapeutic Loadings

    PubMed Central

    Enlow, Elizabeth M.; Luft, J. Christopher; Napier, Mary E.; DeSimone, Joseph M.

    2011-01-01

    Herein we report the fabrication of engineered poly(lactic acid-co-glycolic acid) nanoparticles via the PRINT® (Particle Replication In Non-wetting Templates) process with high and efficient loadings of docetaxel, up to 40% (w/w) with encapsulation efficiencies >90%. The PRINT process enables independent control of particle properties leading to a higher degree of tailorability than traditional methods. Particles with 40% loading display better in vitro efficacy than particles with lower loadings and the clinical formulation of docetaxel, Taxotere®. PMID:21265552

  14. Nanoscale engineering of a cellular interface with semiconductor nanoparticle films for photoelectric stimulation of neurons.

    PubMed

    Pappas, Todd C; Wickramanyake, W M Shan; Jan, Edward; Motamedi, Massoud; Brodwick, Malcolm; Kotov, Nicholas A

    2007-02-01

    The remarkable optical and electrical properties of nanostructured materials are considered now as a source for a variety of biomaterials, biosensing, and cell interface applications. In this study, we report the first example of hybrid bionanodevice where absorption of light by thin films of quantum confined semiconductor nanoparticles of HgTe produced by the layer-by-layer assembly stimulate adherent neural cells via a sequence of photochemical and charge-transfer reactions. We also demonstrate an example of nanoscale engineering of the material driven by biological functionalities. PMID:17298018

  15. Engineering Lysosome-Targeting BODIPY Nanoparticles for Photoacoustic Imaging and Photodynamic Therapy under Near-Infrared Light.

    PubMed

    Hu, Wenbo; Ma, Hengheng; Hou, Bing; Zhao, Hui; Ji, Yu; Jiang, Rongcui; Hu, Xiaoming; Lu, Xiaomei; Zhang, Lei; Tang, Yufu; Fan, Quli; Huang, Wei

    2016-05-18

    Developing lysosome-targeting organic nanoparticles combined with photoacoustic imaging (PAI) and photodynamic therapy (PDT) functions toward personalized medicine are highly desired yet challenging. Here, for the first time, lysosome-targeting BODIPY nanoparticles were engineered by encapsulating near-infrared (NIR) absorbed BODIPY dye within amphiphilic DSPE-mPEG5000 for high-performing lysosomal PAI and acid-activatable PDT against cancer cells under NIR light. PMID:27123534

  16. Interior engineering of a viral nanoparticle and its tumor homing properties

    PubMed Central

    Wen, Amy M.; Shukla, Sourabh; Saxena, Pooja; Aljabali, Alaa A.A.; Yildiz, Ibrahim; Dey, Sourav; Mealy, Joshua E.; Yang, Alice C.; Evans, David J.; Lomonossoff, George P.; Steinmetz, Nicole F.

    2012-01-01

    The development of multifunctional nanoparticles for medical applications is of growing technological interest. A single formulation containing imaging and/or drug moieties that is also capable of preferential uptake in specific cells would greatly enhance diagnostics and treatments. There is growing interest in plant-derived viral nanoparticles (VNPs) and establishing new platform technologies based on these nanoparticles inspired by nature. Cowpea mosaic virus (CPMV) serves as the standard model for VNPs. Although exterior surface modification is well known and has been comprehensively studied, little is known of interior modification. Additional functionality conferred by the capability for interior engineering would be of great benefit toward the ultimate goal of targeted drug delivery. Here, we examined the capacity of empty CPMV (eCPMV) particles devoid of RNA to encapsulate a wide variety of molecules. We systematically investigated the conjugation of fluorophores, biotin affinity tags, large molecular weight polymers such as polyethylene glycol (PEG), and various peptides through targeting reactive cysteines displayed selectively on the interior surface. Several methods are described that mutually confirm specific functionalization of the interior. Finally, CPMV and eCPMV were labeled with near-infrared fluorophores and studied side-by-side in vitro and in vivo. Passive tumor targeting via the enhanced permeability and retention effect and optical imaging were confirmed using a preclinical mouse model of colon cancer. The results of our studies lay the foundation for the development of the eCPMV platform in a range of biomedical applications. PMID:23121655

  17. Properties of Disorder-Engineered Black Titanium Dioxide Nanoparticles through Hydrogenation

    PubMed Central

    Chen, Xiaobo; Liu, Lei; Liu, Zhi; Marcus, Matthew A.; Wang, Wei-Cheng; Oyler, Nathan A.; Grass, Michael E.; Mao, Baohua; Glans, Per-Anders; Yu, Peter Y.; Guo, Jinghua; Mao, Samuel S.

    2013-01-01

    The recent discovery of “black” TiO2 nanoparticles with visible and infrared absorption has triggered an explosion of interest in the application of TiO2 in a diverse set of solar energy systems; however, what a black TiO2 nanoparticle really is remains a mystery. Here we elucidate more properties and try to understand the inner workings of black TiO2 nanoparticles with hydrogenated disorders in a surface layer surrounding a crystalline core. Contrary to traditional findings, Ti3+ here is not responsible for the visible and infrared absorption of black TiO2, while there is evidence of mid-gap states above the valence band maximum due to the hydrogenated, engineered disorders. The hydrogen atoms, on the other hand, can undergo fast diffusion and exchange. The enhanced hydrogen mobility may be explained by the presence of the hydrogenated, disordered surface layer. This unique structure thus may give TiO2, one of the most-studied oxide materials, a renewed potential. PMID:23528851

  18. Engineered nanoparticle respiratory exposure and potential risks for cardiovascular toxicity: predictive tests and biomarkers.

    PubMed

    Simeonova, Petia P; Erdely, Aaron

    2009-07-01

    The most attractive properties of engineered nanomaterials for technological applications, including their small size, large surface area, and high reactivity, are also the main factors for their potential toxicity. Based on ambient ultrafine particle research, it is predicted that nanosized particles may have deeper pulmonary deposition, higher biological activity, and a tendency for extrapulmonary translocation compared to larger particles. In this regard, nanoparticle exposure, by direct or indirect mechanisms, may lead to unexpected distant responses, involving the immune system, cardiovascular system, liver, kidney, and brain. The systemic effects may induce or modify the progression of existing diseases such as cardiovascular disease. Current experimental toxicity evaluation of engineered nanomaterials, specifically carbon nanotubes, demonstrated that deposition of these materials in the lung leads to inflammation and fibrosis. The local toxicity is associated with cardiovascular effects related to atherosclerosis. Although translocation of carbon nanotubes into the systemic circulation is hypothetically possible, there is no current evidence to support this hypothesis. However, studies pointed out that carbon nanotube-induced lung inflammation results in a release of inflammatory mediators and activation of blood cells which can contribute to cardiovascular adverse effects. Furthermore, complex protein and gene expression blood analysis can help in development of biomarkers for application in human screening of nanoparticle exposure. Future studies to evaluate the systemic effects of carbon nanotube exposure under workplace or environmental exposure paradigms should be conducted. PMID:19558236

  19. Transport and deposition of stabilized engineered silver nanoparticles in water saturated loamy sand and silty loam.

    PubMed

    Braun, Anika; Klumpp, Erwin; Azzam, Rafig; Neukum, Christoph

    2015-12-01

    It is considered inevitable that the increasing production and application of engineered nanoparticles will lead to their release into the environment. However, the behavior of these materials under environmentally relevant conditions is still only poorly understood. In this study the transport and deposition behavior of engineered surfactant stabilized silver nanoparticles (AgNPs) in water saturated porous media was investigated in transport experiments with glass beads as reference porous medium and in two natural soils under various hydrodynamic and hydrochemical conditions. The transport and retention processes of AgNPs in the porous media were elucidated by inverse modeling and possible particle size changes occurring during the transport through the soil matrix were analyzed with flow field-flow fractionation (FlFFF). A high mobility of AgNPs was observed in loamy sand under low ionic strength (IS) conditions and at high flow rates. The transport was inhibited at low flow rates, at higher IS, in the presence of divalent cations and in a more complex, fine-grained silty loam. The slight decrease of the mean particle size of the AgNPs in almost all experiments indicates size selective filtration processes and enables the exclusion of homoaggregation processes. PMID:25527873

  20. Detection of Engineered Copper Nanoparticles in Soil Using Single Particle ICP-MS

    PubMed Central

    Navratilova, Jana; Praetorius, Antonia; Gondikas, Andreas; Fabienke, Willi; von der Kammer, Frank; Hofmann, Thilo

    2015-01-01

    Regulatory efforts rely on nanometrology for the development and implementation of laws regarding the incorporation of engineered nanomaterials (ENMs) into industrial and consumer products. Copper is currently one of the most common metals used in the constantly developing and expanding sector of nanotechnology. The use of copper nanoparticles in products, such as agricultural biocides, cosmetics and paints, is increasing. Copper based ENMs will eventually be released to the environment through the use and disposal of nano-enabled products, however, the detection of copper ENMs in environmental samples is a challenging task. Single particle inductively coupled plasma mass spectroscopy (spICP-MS) has been suggested as a powerful tool for routine nanometrology efforts. In this work, we apply a spICP-MS method for the detection of engineered copper nanomaterials in colloidal extracts from natural soil samples. Overall, copper nanoparticles were successfully detected in the soil colloidal extracts and the importance of dwell time, background removal, and sample dilution for method optimization and recovery maximization is highlighted. PMID:26690460

  1. Microfluidic Buffer Exchange for Interference-free Micro/Nanoparticle Cell Engineering.

    PubMed

    Tay, Hui Min; Yeo, David C; Wiraja, Christian; Xu, Chenjie; Hou, Han Wei

    2016-01-01

    Engineering cells with active-ingredient-loaded micro/nanoparticles (NPs) is becoming an increasingly popular method to enhance native therapeutic properties, enable bio imaging and control cell phenotype. A critical yet inadequately addressed issue is the significant number of particles that remain unbound after cell labeling which cannot be readily removed by conventional centrifugation. This leads to an increase in bio imaging background noise and can impart transformative effects onto neighboring non-target cells. In this protocol, we present an inertial microfluidics-based buffer exchange strategy termed as Dean Flow Fractionation (DFF) to efficiently separate labeled cells from free NPs in a high throughput manner. The developed spiral microdevice facilitates continuous collection (>90% cell recovery) of purified cells (THP-1 and MSCs) suspended in new buffer solution, while achieving >95% depletion of unbound fluorescent dye or dye-loaded NPs (silica or PLGA). This single-step, size-based cell purification strategy enables high cell processing throughput (10(6) cells/min) and is highly useful for large-volume cell purification of micro/nanoparticle engineered cells to achieve interference-free clinical application. PMID:27500904

  2. Comparative in vitro cytotoxicity assessment of airborne particulate matter emitted from stationary engine fuelled with diesel and waste cooking oil-derived biodiesel

    NASA Astrophysics Data System (ADS)

    Betha, Raghu; Pavagadhi, Shruti; Sethu, Swaminathan; Hande, M. Prakash; Balasubramanian, Rajasekhar

    2012-12-01

    Biodiesel derived from waste cooking oil (WCO) is gaining increased attention as an alternative fuel due to lower particulate emissions and other beneficial factors such as low cost and utilization of waste oil. However, very little information is available on toxicity of airborne particulate matter (PM) emitted from biodiesel combustion. In this study, PM emitted from WCO-derived biodiesel (B100) was analyzed for its toxic potential together with ultra low sulphur diesel (ULSD) as a reference fuel and their blend (B50). Human lung epithelial carcinoma cells (A549) were used for this comparative toxicity study. Results indicate that cytotoxicity and oxidative stress were higher for B100 relative to ULSD. Furthermore, caspase 3/7 activity indicates that cell death induced by B100 was due to either caspase independent apoptotic process or other programmed cell death pathways. The toxicity was also evaluated for different engine load conditions. It was observed that at lower loads there was no significant difference in the toxicological response of B100 and ULSD. However, with increase in the engine load, B100 and B50 showed significantly higher toxicity and oxidative stress compared to ULSD.

  3. Seismic characterization of select engineered nanoparticles in essentially saturated glass beads

    NASA Astrophysics Data System (ADS)

    Rajabdeen, Mohamed Nihad

    2011-12-01

    A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline signatures. Then the seismic responses in the presence of engineered nanoparticles of various concentrations dispersed in the pore fluid of the specimen chamber were studied to observe variances from baseline. The testing apparatus incorporates piezoceramic bender elements to actuate and receive seismic body waves through a cylindrical column filled with glass beads and back-saturated at ambient pressure with liquid. The system was calibrated in air, water, and water-saturated glass beads. System repeatability was checked after the system was saturated and flushed once to soak and seat the beads. The water-saturated glass bead specimens were tested for compression, shear, and spectral response, from which baseline signatures were established. Criteria were proposed to evaluate the detectability of nanoparticle dispersions. Nanoparticle dispersions of zinc oxide (nZnO), titanium dioxide (nTiO 2), and silver (nAg) were tested. The testing system showed itself to be capable of registering subtle changes in the response caused by varying consolidation states of the glass beads and pore fluid content. The presence of nZnO was detectable for all the test methods except compression wave arrivals, nAg was detectable only by compression wave amplitude and spectral response and nTiO2 showed only subtle detectability for spectral response.

  4. Low biosorption of PVA coated engineered magnetic nanoparticles in granular sludge assessed by magnetic susceptibility.

    PubMed

    Herrling, Maria P; Fetsch, Katharina L; Delay, Markus; Blauert, Florian; Wagner, Michael; Franzreb, Matthias; Horn, Harald; Lackner, Susanne

    2015-12-15

    When engineered nanoparticles (ENP) enter into wastewater treatment plants (WWTP) their removal from the water phase is driven by the interactions with the biomass in the biological treatment step. While studies focus on the interactions with activated flocculent sludge, investigations on the detailed distribution of ENP in other types of biomass, such as granulated sludge, are needed to assess their potential environmental pollution. This study employed engineered magnetic nanoparticles (EMNP) coated with polyvinyl alcohol (PVA) as model nanoparticles to trace their fate in granular sludge from WWT. For the first time, magnetic susceptibility was used as a simple approach for the in-situ quantification of EMNP with a high precision (error <2%). Compared to other analytical methods, the magnetic susceptibility requires no sample preparation and enabled direct quantification of EMNP in both the aqueous phase and the granular sludge. In batch experiments granular sludge was exposed to EMNP suspensions for 18 h. The results revealed that the removal of EMNP from the water phase (5-35%) and biosorption in the granular sludge were rather low. Less than 2.4% of the initially added EMNP were associated with the biomass. Loosely bounded to the granular sludge, desorption of EMNP occurred. Consequently, the removal of EMNP was mainly driven by physical co-sedimentation with the biomass instead of sorption processes. A mass balance elucidated that the majority of EMNP were stabilized by particulate organic matter in the water phase and can therefore likely be transported further. The magnetic susceptibility enabled tracing EMNP in complex matrices and thus improves the understanding of the general distribution of ENP in technical as well as environmental systems. PMID:26282738

  5. Engineering of hollow mesoporous silica nanoparticles for remarkably enhanced tumor active targeting efficacy.

    PubMed

    Chen, Feng; Hong, Hao; Shi, Sixiang; Goel, Shreya; Valdovinos, Hector F; Hernandez, Reinier; Theuer, Charles P; Barnhart, Todd E; Cai, Weibo

    2014-01-01

    Hollow mesoporous silica nanoparticle (HMSN) has recently gained increasing interests due to their tremendous potential as an attractive nano-platform for cancer imaging and therapy. However, possibly due to the lack of efficient in vivo targeting strategy and well-developed surface engineering techniques, engineering of HMSN for in vivo active tumor targeting, quantitative tumor uptake assessment, multimodality imaging, biodistribution and enhanced drug delivery have not been achieved to date. Here, we report the in vivo tumor targeted positron emission tomography (PET)/near-infrared fluorescence (NIRF) dual-modality imaging and enhanced drug delivery of HMSN using a generally applicable surface engineering technique. Systematic in vitro and in vivo studies have been performed to investigate the stability, tumor targeting efficacy and specificity, biodistribution and drug delivery capability of well-functionalized HMSN nano-conjugates. The highest uptake of TRC105 (which binds to CD105 on tumor neovasculature) conjugated HMSN in the 4T1 murine breast cancer model was ~10%ID/g, 3 times higher than that of the non-targeted group, making surface engineered HMSN a highly attractive drug delivery nano-platform for future cancer theranostics. PMID:24875656

  6. Engineering of Hollow Mesoporous Silica Nanoparticles for Remarkably Enhanced Tumor Active Targeting Efficacy

    PubMed Central

    Chen, Feng; Hong, Hao; Shi, Sixiang; Goel, Shreya; Valdovinos, Hector F.; Hernandez, Reinier; Theuer, Charles P.; Barnhart, Todd E.; Cai, Weibo

    2014-01-01

    Hollow mesoporous silica nanoparticle (HMSN) has recently gained increasing interests due to their tremendous potential as an attractive nano-platform for cancer imaging and therapy. However, possibly due to the lack of efficient in vivo targeting strategy and well-developed surface engineering techniques, engineering of HMSN for in vivo active tumor targeting, quantitative tumor uptake assessment, multimodality imaging, biodistribution and enhanced drug delivery have not been achieved to date. Here, we report the in vivo tumor targeted positron emission tomography (PET)/near-infrared fluorescence (NIRF) dual-modality imaging and enhanced drug delivery of HMSN using a generally applicable surface engineering technique. Systematic in vitro and in vivo studies have been performed to investigate the stability, tumor targeting efficacy and specificity, biodistribution and drug delivery capability of well-functionalized HMSN nano-conjugates. The highest uptake of TRC105 (which binds to CD105 on tumor neovasculature) conjugated HMSN in the 4T1 murine breast cancer model was ~10%ID/g, 3 times higher than that of the non-targeted group, making surface engineered HMSN a highly attractive drug delivery nano-platform for future cancer theranostics. PMID:24875656

  7. Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products

    PubMed Central

    Pirela, Sandra V.; Sotiriou, Georgios A.; Bello, Dhimiter; Shafer, Martin; Bunker, Kristin Lee; Castranova, Vincent; Thomas, Treye; Demokritou, Philip

    2015-01-01

    It is well established that printers emit nanoparticles during their operation. To-date, however, the physicochemical and toxicological characterization of “real world” printer-emitted nanoparticles (PEPs) remains incomplete, hampering proper risk assessment efforts. Here, we investigate our earlier hypothesis that engineered nanomaterials (ENMs) are used in toners and ENMs are released during printing (consumer use). Furthermore, we conduct a detailed physicochemical and morphological characterization of PEPs in support of ongoing toxicological assessment. A comprehensive suite of state of the art analytical methods and tools was employed for the physicochemical and morphological characterization of 11 toners widely utilized in printers from major printer manufacturers and their PEPs. We confirmed that a number of ENMs incorporated into toner formulations (e.g., silica, alumina, titania, iron oxide, zinc oxide, copper oxide, cerium oxide, carbon black among others) and released into the air during printing. All evaluated toners contained large amounts of organic carbon (OC, 42–89%), metals/metal oxides (1–33%), and some elemental carbon (EC, 0.33–12%). The PEPs possess a composition similar to that of toner and contained 50–90% OC, 0.001–0.5% EC and 1–3% metals. While the chemistry of the PEPs generally reflected that of their toners, considerable differences are documented indicative of potential transformations taking place during consumer use (printing). We conclude that: (i) Routine incorporation of ENMs in toners classifies them as nano-enabled products (NEPs); (ii) These ENMs become airborne during printing; (iii) The chemistry of PEPs is complex and it reflects that of the toner and paper. This work highlights the importance of understanding life-cycle (LC) nano-EHS implications of NEPs and assessing real world exposures and associated toxicological properties rather than focusing on “raw” materials used in the synthesis of an NEP. PMID

  8. Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products.

    PubMed

    Pirela, Sandra V; Sotiriou, Georgios A; Bello, Dhimiter; Shafer, Martin; Bunker, Kristin Lee; Castranova, Vincent; Thomas, Treye; Demokritou, Philip

    2015-01-01

    It is well established that printers emit nanoparticles during their operation. To-date, however, the physicochemical and toxicological characterization of "real world" printer-emitted nanoparticles (PEPs) remains incomplete, hampering proper risk assessment efforts. Here, we investigate our earlier hypothesis that engineered nanomaterials (ENMs) are used in toners and ENMs are released during printing (consumer use). Furthermore, we conduct a detailed physicochemical and morphological characterization of PEPs in support of ongoing toxicological assessment. A comprehensive suite of state of the art analytical methods and tools was employed for the physicochemical and morphological characterization of 11 toners widely utilized in printers from major printer manufacturers and their PEPs. We confirmed that a number of ENMs incorporated into toner formulations (e.g. silica, alumina, titania, iron oxide, zinc oxide, copper oxide, cerium oxide, carbon black among others) and released into the air during printing. All evaluated toners contained large amounts of organic carbon (OC, 42-89%), metals/metal oxides (1-33%), and some elemental carbon (EC, 0.33-12%). The PEPs possess a composition similar to that of toner and contained 50-90% OC, 0.001-0.5% EC and 1-3% metals. While the chemistry of the PEPs generally reflected that of their toners, considerable differences are documented indicative of potential transformations taking place during consumer use (printing). We conclude that: (i) Routine incorporation of ENMs in toners classifies them as nano-enabled products (NEPs); (ii) These ENMs become airborne during printing; (iii) The chemistry of PEPs is complex and it reflects that of the toner and paper. This work highlights the importance of understanding life-cycle (LC) nano-EHS implications of NEPs and assessing real world exposures and associated toxicological properties rather than focusing on "raw" materials used in the synthesis of an NEP. PMID:25387251

  9. Engineering Nanostructures by Decorating Magnetic Nanoparticles onto Graphene Oxide Sheets to Shield Electromagnetic Radiations.

    PubMed

    Mural, Prasanna Kumar S; Pawar, Shital Patangrao; Jayanthi, Swetha; Madras, Giridhar; Sood, Ajay K; Bose, Suryasarathi

    2015-08-01

    In this study, a minimum reflection loss of -70 dB was achieved for a 6 mm thick shield (at 17.1 GHz frequency) employing a unique approach. This was accomplished by engineering nanostructures through decoration of magnetic nanoparticles (nickel, Ni) onto graphene oxide (GO) sheets. Enhanced electromagnetic (EM) shielding was derived by selectively localizing the nanoscopic particles in a specific phase of polyethylene (PE)/poly(ethylene oxide) (PEO) blends. By introduction of a conducting inclusion (like multiwall carbon nanotubes, MWNTs) together with the engineered nanostructures (nickel-decorated GO, GO-Ni), the shielding efficiency can be enhanced significantly in contrast to physically mixing the particles in the blends. For instance, the composites showed a shielding efficiency >25 dB for a combination of MWNTs (3 wt %) and Ni nanoparticles (52 wt %) in PE/PEO blends. However, similar shielding effectiveness could be achieved for a combination of MWNTs (3 wt %) and 10 vol % of GO-Ni where in the effective concentration of Ni was only 19 wt %. The GO-Ni sheets facilitated in an efficient charge transfer as manifested from high electrical conductivity in the blends besides enhancing the permeability in the blends. It is envisioned that GO is simultaneously reduced in the process of synthesizing GO-Ni, and this facilitated in efficient charge transfer between the neighboring CNTs. More interestingly, the blends with MWNTs/GO-Ni attenuated the incoming EM radiation mostly by absorption. This study opens new avenues in designing polyolefin-based lightweight shielding materials by engineering nanostructures for numerous applications. PMID:26176935

  10. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  11. Inflammatory and Oxidative Stress Responses of an Alveolar Epithelial Cell Line to Airborne Zinc Oxide Nanoparticles at the Air-Liquid Interface: A Comparison with Conventional, Submerged Cell-Culture Conditions

    PubMed Central

    Lenz, Anke-Gabriele; Karg, Erwin; Brendel, Ellen; Hinze-Heyn, Helga; Maier, Konrad L.; Eickelberg, Oliver; Stoeger, Tobias; Schmid, Otmar

    2013-01-01

    The biological effects of inhalable nanoparticles have been widely studied in vitro with pulmonary cells cultured under submerged and air-liquid interface (ALI) conditions. Submerged exposures are experimentally simpler, but ALI exposures are physiologically more realistic and hence potentially biologically more meaningful. In this study, we investigated the cellular response of human alveolar epithelial-like cells (A549) to airborne agglomerates of zinc oxide (ZnO) nanoparticles at the ALI, compared it to the response under submerged culture conditions, and provided a quantitative comparison with the literature data on different types of particles and cells. For ZnO nanoparticle doses of 0.7 and 2.5 μg ZnO/cm2 (or 0.09 and 0.33 cm2 ZnO/cm2), cell viability was not mitigated and no significant effects on the transcript levels of oxidative stress markers (HMOX1, SOD-2 and GCS) were observed. However, the transcript levels of proinflammatory markers (IL-8, IL-6, and GM-CSF) were induced to higher levels under ALI conditions. This is consistent with the literature data and it suggests that in vitro toxicity screening of nanoparticles with ALI cell culture systems may produce less false negative results than screening with submerged cell cultures. However, the database is currently too scarce to draw a definite conclusion on this issue. PMID:23484138

  12. Airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-06-01

    The US Air Force Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the risk reduction approach being utilized to ensure program success.

  13. The effects of surface aging on nanoparticle fate and transport in natural and engineered porous media

    NASA Astrophysics Data System (ADS)

    Mittelman, Anjuliee M.

    Nanomaterials will be subjected to various surface transformations in the environment and within water and wastewater treatment systems. A comprehensive understanding of the fate and transport behavior of "aged" nanomaterials in both natural and engineered porous media is required in order to accurately quantify ecological and human health risks. This research sought to (1) evaluate the impact of ultraviolet (UV) light aging on nanoparticle transport in water-saturated porous media; and (2) assess the effects of influent water quality on silver nanoparticle retention and dissolution in ceramic water filters. Additionally, the value of quartz crystal microbalance (QCM-D) data in nanoparticle fate and transport studies was evaluated by comparing deposition behavior in complementary QCM-D and sand columns experiments. Silver (nAg) and iron oxide nanoparticles exposed to UV light were up to 50% more strongly retained in porous media compared with freshly prepared suspensions due to less negative surface charge and larger aggregate sizes. UV-aged nAg were more prone to dissolution in sand columns, resulting in effluent Ag+ concentrations as high as 1.2 mg/L. In ceramic water filters, dissolution and cation exchange processes controlled silver release into treated water. The use of acidic, high salinity, or high hardness water accelerated oxidative dissolution of the silver coating and resulted in effluent silver concentrations 5-10 times above international drinking water guidelines. Results support the recommendation for a regular filter replacement or silver re-application schedule to ensure ongoing efficacy. Taken in concert, these research findings suggest that oxidative aging of nanomaterial surfaces (either through exposure to UV light or aggressive water chemistries) will alter the fate of nanomaterials in the environment and may decrease the effective lifetime of devices which utilize nanotechnology. Corresponding QCM-D and column experiments revealed that

  14. Small Angle X-ray Scattering Study of Palladium Nanoparticle Growth on Genetically Engineered Tobacco Mosaic Virus Nanotemplates

    NASA Astrophysics Data System (ADS)

    Manocchi, Amy K.

    Transition metal nanoparticles possess valuable specific size dependent properties that arise at the nanoscale, and differ significantly from their bulk properties. However, the fabrication of these nanoparticles is often difficult to predict and control due to harsh reaction conditions and effects of capping agents or surfactants. Therefore, there is a critical need for facile routes toward controllable nanoparticle fabrication. Biological supramolecules, such as viruses, offer attractive templates for nanoparticle synthesis, due to their precise size and shape. In addition, simple genetic modifications can be employed to confer additional functionality with a high number of precisely spaced functional groups. In this work we exploit the specificity of genetically modified Tobacco Mosaic Virus (TMV1cys) for readily controllable palladium (Pd) nanoparticle synthesis via simple electroless deposition. TMV1cys, engineered to display one cysteine residue on the surface of each of over 2000 identical coat proteins, provides high density precisely spaced thiol groups for the preferential nucleation and growth of Pd nanoparticles. Small-Angle X-ray Scattering (SAXS) was employed to provide a statistically meaningful route to the investigation of Pd nanoparticle size ranges formed on the viral-nanotemplates. Specifically, we examine the size range and thermal stability of Pd nanoparticles formed on surface assembled TMV1cys. Further, we investigate the growth of Pd nanoparticles on TMV1cys in solution using in situ SAXS to better understand and predict nanoparticle growth on these nanotemplates. Lastly, we compare TMV1cys templated particle growth to Pd nanoparticle growth in the absence of TMV1cys to elucidate the role of TMV in particle formation. We show that Pd nanoparticles form preferentially on surface assembled TMV1cys in high density in a broad particle size range (4-18nm). Further, we show that Pd nanoparticles are significantly smaller and more uniform when

  15. Sensing the Presence and Transport of Engineered Nanoparticles in Saturated PorousMedia using Spectral Induced Polarization (SIP) Method

    EPA Science Inventory

    Nano-materials are emerging into the global marketplace. Engineered Nano-particles, and other throwaway nanodevices may constitute a whole new class of non-biodegradable pollutants of which scientists have very little understanding. Therefore, the production of significant quanti...

  16. Synthesis of Hollow Gold-Silver Alloyed Nanoparticles: A "Galvanic Replacement" Experiment for Chemistry and Engineering Students

    ERIC Educational Resources Information Center

    Jenkins, Samir V.; Gohman, Taylor D.; Miller, Emily K.; Chen, Jingyi

    2015-01-01

    The rapid academic and industrial development of nanotechnology has led to its implementation in laboratory teaching for undergraduate-level chemistry and engineering students. This laboratory experiment introduces the galvanic replacement reaction for synthesis of hollow metal nanoparticles and investigates the optical properties of these…

  17. Effect of engineered nanoparticles on vasomotor responses in rat intrapulmonary artery

    SciTech Connect

    Courtois, Arnaud; Andujar, Pascal; Ladeiro, Yannick; Ducret, Thomas; Rogerieux, Francoise; Lacroix, Ghislaine; Baudrimont, Isabelle; Guibert, Christelle; Roux, Etienne; Canal-Raffin, Mireille; Brochard, Patrick; Marano, Francelyne; Marthan, Roger; Muller, Bernard

    2010-06-01

    Pulmonary circulation could be one of the primary vascular targets of finest particles that can deeply penetrate into the lungs after inhalation. We investigated the effects of engineered nanoparticles on vasomotor responses of small intrapulmonary arteries using isometric tension measurements. Acute in vitro exposure to carbon nanoparticles (CNP) decreased, and in some case abolished, the vasomotor responses induced by several vasoactive agents, whereas acute exposure to titanium dioxide nanoparticles (TiO{sub 2}NP) did not. This could be attributed to a decrease in the activity of those vasoactive agents (including PGF{sub 2{alpha}}, serotonin, endothelin-1 and acetylcholine), as suggested when they were exposed to CNP before being applied to arteries. Also, CNP decreased the contraction induced by 30 mM KCl, without decreasing its activity. After endoplasmic reticulum calcium stores depletion (by caffeine and thapsigargin), CaCl{sub 2} addition induced a contraction, dependent on Store-Operated Calcium Channels that was not modified by acute CNP exposure. Further addition of 30 mM KCl elicited a contraction, originating from activation of Voltage-Operated Calcium Channels that was diminished by CNP. Contractile responses to PGF{sub 2{alpha}} or KCl, and relaxation to acetylcholine were modified neither in pulmonary arteries exposed in vitro for prolonged time to CNP or TiO{sub 2}NP, nor in those removed from rats intratracheally instilled with CNP or TiO{sub 2}NP. In conclusion, prolonged in vitro or in vivo exposure to CNP or TiO{sub 2}NP does not affect vasomotor responses of pulmonary arteries. However, acute exposure to CNP decreases contraction mediated by activation of Voltage-Operated, but not Store-Operated, Calcium Channels. Moreover, interaction of some vasoactive agents with CNP decreases their biological activity that might lead to misinterpretation of experimental data.

  18. Electrospun aligned PLGA and PLGA/gelatin nanofibers embedded with silica nanoparticles for tissue engineering.

    PubMed

    Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Ghaedi, Kamran; Salehi, Hossein; Arpanaei, Ayyoob

    2015-08-01

    Aligned poly lactic-co-glycolic acid (PLGA) and PLGA/gelatin nanofibrous scaffolds embedded with mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. The mean diameters of nanofibers were 641±24 nm for the pure PLGA scaffolds vs 418±85 nm and 267±58 nm for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The contact angle measurement results (102°±6.7 for the pure PLGA scaffold vs 81°±6.8 and 18°±8.7 for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively) revealed enhanced hydrophilicity of scaffolds upon incorporation of gelatin and MSNPs. Besides, embedding the scaffolds with MSNPs resulted in improved tensile mechanical properties. Cultivation of PC12 cells on the scaffolds demonstrated that introduction of MSNPs into PLGA and PLGA/gelatin matrices leads to the improved cell attachment and proliferation as well as long cellular processes. DAPI staining results indicated that cell proliferations on the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds were strikingly (nearly 2.5 and 3 folds, respectively) higher than that on the aligned pure PLGA scaffolds. These results suggest superior properties of silica nanoparticles-incorporated PLGA/gelatin eletrospun nanofibrous scaffolds for the stem cell culture and tissue engineering applications. PMID:26045092

  19. Effects of Engineered Nanoparticles on the Assembly of Exopolymeric Substances from Phytoplankton

    PubMed Central

    Zhang, Saijin; Spurgin, Jessica; Chuang, Chia-Ying; Xu, Chen; Miao, Ai-Jun; Chen, Eric Y-T.; Schwehr, Kathleen A.; Jiang, Yuelu; Quigg, Antonietta; Santschi, Peter H.; Chin, Wei-Chun

    2011-01-01

    The unique properties of engineered nanoparticles (ENs) that make their industrial applications so attractive simultaneously raise questions regarding their environmental safety. ENs exhibit behaviors different from bulk materials with identical chemical compositions. Though the nanotoxicity of ENs has been studied intensively, their unintended environmental impacts remain largely unknown. Herein we report experimental results of EN interactions with exopolymeric substances (EPS) from three marine phytoplankton species: Amphora sp., Ankistrodesmus angustus and Phaeodactylum tricornutum. EPS are polysaccharide-rich anionic colloid polymers released by various microorganisms that can assemble into microgels, possibly by means of hydrophobic and ionic mechanisms. Polystyrene nanoparticles (23 nm) were used in our study as model ENs. The effects of ENs on EPS assembly were monitored with dynamic laser scattering (DLS). We found that ENs can induce significant acceleration in Amphora sp. EPS assembly; after 72 hours EN-EPS aggregation reached equilibrium, forming microscopic gels of ∼4–6 µm in size. In contrast, ENs only cause moderate assembly kinetic acceleration for A. angustus and P. tricornutum EPS samples. Our results indicate that the effects of ENs on EPS assembly kinetics mainly depend on the hydrophobic interactions of ENs with EPS polymers. The cycling mechanism of EPS is complex. Nonetheless, the change of EPS assembly kinetics induced by ENs can be considered as one potential disturbance to the marine carbon cycle. PMID:21811550

  20. Engineered Nanoparticles as Potential Food Contaminants and Their Toxicity to Caco-2 Cells.

    PubMed

    Mao, Xiaomo; Nguyen, Trang H D; Lin, Mengshi; Mustapha, Azlin

    2016-08-01

    Engineered nanoparticles (ENPs), such as metallic or metallic oxide nanoparticles (NPs), have gained much attention in recent years. Increasing use of ENPs in various areas may lead to the release of ENPs into the environment and cause the contamination of agricultural and food products by ENPs. In this study, we selected two important ENPs (zinc oxide [ZnO] and silver [Ag] NPs) as potential food contaminants and investigated their toxicity via an in vitro model using Caco-2 cells. The physical properties of ENPs and their effects on Caco-2 cells were characterized by electron microscopy and energy dispersive X-ray spectroscopic (EDS) techniques. Results demonstrate that a significant inhibition of cell viability was observed after a 24-h of exposure of Caco-2 cells to 3-, 6-, and 12-mM ZnO NPs or 0.5-, 1.5-, and 3-mM Ag NPs. The noticeable changes of cells include the alteration in cell shape, abnormal nuclear structure, membrane blebbing, and cytoplasmic deterioration. The toxicity of ZnO NPs, but not that of Ag NPs after exposure to simulated gastric fluid, significantly decreased. Scanning transmission electron microscopy shows that ZnO and Ag NPs penetrated the membrane of Caco-2 cells. EDS results also confirm the presence of NPs in the cytoplasm of the cells. This study demonstrates that ZnO and Ag NPs have cytotoxic effects and can inhibit the growth of Caco-2 cells. PMID:27505352

  1. Natural organic matter concentration and hydrochemistry influence aggregation kinetics of functionalized engineered nanoparticles.

    PubMed

    Liu, Junfeng; Legros, Samuel; von der Kammer, Frank; Hofmann, Thilo

    2013-05-01

    Understanding the colloidal stability of functionalized engineered nanoparticles (FENPs) in aquatic environments is of paramount importance in order to assess the risk related to FENPs. In this study, gold nanoparticles (GNPs) of 68 and 43 nm diameter, coated with citrate and 11-mercaptoundecanoic acid (MUA) respectively, were used as models of FENPs. Time-resolved dynamic light scattering was employed to investigate the aggregation kinetics of two types of GNPs. The results show that without Suwannee river natural organic matter (SRNOM), MUA coating resulted in greater stability than citrate coating for GNPs. Cations have a destabilizing effect on both GNPs following the order Ca(2+) ≈ Mg(2+) > Na(+); different anions (Cl(-) and SO4(2-)) showed no difference in effects. In the fast aggregation regime, adding SRNOM enhanced the stability of MUA-coated GNPs in both Ca(2+) and Mg(2+) solutions. However citrate-coated GNPs were only stabilized in Mg(2+) solution but enhanced aggregation occurred in high Ca(2+) concentration due to interparticle bridging. For the investigated GNPs and in the presence of SRNOM, Ca(2+) does not always act as a strong coagulant. This indicates that for the new materials emerging from the application of nanotechnology the well-described aggregation mechanisms of colloids in the environment require a detailed re-examination. PMID:23560437

  2. Bisphosphonate-adsorbed ceramic nanoparticles increase bone formation in an injectable carrier for bone tissue engineering.

    PubMed

    Cheng, Tegan L; Murphy, Ciara M; Ravarian, Roya; Dehghani, Fariba; Little, David G; Schindeler, Aaron

    2015-01-01

    Sucrose acetate isobutyrate (SAIB) is a sugar-based carrier. We have previously applied SAIB as a minimally invasive system for the co-delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) and found synergy when co-delivering zoledronic acid (ZA) and hydroxyapatite (HA) nanoparticles. Alternative bioceramics were investigated in a murine SAIB/rhBMP-2 injection model. Neither beta-tricalcium phosphate (TCP) nor Bioglass (BG) 45S5 had a significant effect on bone volume (BV) alone or in combination with the ZA. (14)C-labelled ZA binding assays showed particle size and ceramic composition affected binding with nano-HA > micro-HA > TCP > BG. Micro-HA and nano-HA increased BV in a rat model of rhBMP-2/SAIB injection (+278% and +337%), and BV was further increased with ZA-adsorbed micro-HA and nano-HA (+530% and +889%). These data support the use of ZA-adsorbed nanoparticle-sized HA as an optimal additive for the SAIB/rhBMP-2 injectable system for bone tissue engineering. PMID:26668709

  3. Bisphosphonate-adsorbed ceramic nanoparticles increase bone formation in an injectable carrier for bone tissue engineering

    PubMed Central

    Cheng, Tegan L; Murphy, Ciara M; Ravarian, Roya; Dehghani, Fariba; Little, David G; Schindeler, Aaron

    2015-01-01

    Sucrose acetate isobutyrate (SAIB) is a sugar-based carrier. We have previously applied SAIB as a minimally invasive system for the co-delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) and found synergy when co-delivering zoledronic acid (ZA) and hydroxyapatite (HA) nanoparticles. Alternative bioceramics were investigated in a murine SAIB/rhBMP-2 injection model. Neither beta-tricalcium phosphate (TCP) nor Bioglass (BG) 45S5 had a significant effect on bone volume (BV) alone or in combination with the ZA. 14C-labelled ZA binding assays showed particle size and ceramic composition affected binding with nano-HA > micro-HA > TCP > BG. Micro-HA and nano-HA increased BV in a rat model of rhBMP-2/SAIB injection (+278% and +337%), and BV was further increased with ZA–adsorbed micro-HA and nano-HA (+530% and +889%). These data support the use of ZA–adsorbed nanoparticle-sized HA as an optimal additive for the SAIB/rhBMP-2 injectable system for bone tissue engineering. PMID:26668709

  4. Engineering nanoparticles surface for biosensing: "Chemical noses" to detect and identify proteins, bacteria and cancerous cells

    NASA Astrophysics Data System (ADS)

    Miranda-Sanchez, Oscar Ramon

    Rapid and sensitive detection of biomolecules is an important issue in nanomedicine. Many disorders are manifested by changes in protein levels of serum and other biofluids. Rapid and effective differentiation between normal and cancerous cells is an important challenge for the diagnosis and treatment of tumor. Likewise, rapid and effective identification of pathogens is a key target in both biomedical and environmental monitoring. Most biological recognition processes occur via specific interactions. Gold nanoparticles (AuNP s) feature sizes commensurate with biomacromolecules, coupled with useful physical and optical properties. A key issue in the use of nanomaterials is controlling the interfacial interactions of these complex systems. Modulation of these physicochemical properties can be readily achieved by engineering nanoparticles surface. Inspired by the idea of mimicking nature, a convenient, precise and rapid method for sensing proteins, cancerous cells and bacteria has been developed by overtaking the superb performance of biological olfactory systems in odor detection, identification, tracking, and location. On the fundamental side, an array-based/'chemical nose' sensor composed of cationic functionalized AuNPs as receptors and anionic fluorescent conjugated polymers or green fluorescent proteins or enzyme/substrates as transducers that can properly detect and identify proteins, bacteria, and cancerous cells has been successfully fabricated.

  5. Floodplain mesocosm system for studying environmental fate and effects of engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Schaumann, Gabriele E.; Steinmetz, Zacharias; Metreveli, George; Vogel, Hans-Jörg; Bundschuh, Mirco; Baumann, Thomas; Schulz, Ralf; Lang, Friederike; Seitz, Frank; Rosenfeldt, Ricki R.; Manz, Werner

    2015-04-01

    Once released into the environment, engineered inorganic nanoparticles (EINPs) will undergo chemical and physical transformation processes. The fate, ecotoxicological potential, and mobility of EINPs in environmental compartments will be influenced predominantly by their aging and current speciation status. In order to understand the aging mechanisms and impact of ENP transformations on their distribution and bioavailability in real environmental systems, mesocosm studies can be helpful. The INTERNANO floodplain mesocosm links aquatic and terrestrial aging phases in one system and has been conceived as near-natural test system to evaluate and further develop process understanding on aging and functioning of EINP in the aquatic-terrestrial transition zone. The mesocosm system is run with a pulse input function of EINP in order to investigate the response of the chemical, physico-chemical and biological systems over time. Immission into the soil system is performed via flooding events. The system is run with natural river water, natural repacked soil but with quartz sand as sediment phase. Convective water exchange between soil and aquatic compartments occurs at high water level. On this poster, we will present the design of the mesocosm system together with first findings on fate and biological effects of silver nanoparticles.

  6. Potential exposure of German consumers to engineered nanoparticles in cosmetics and personal care products.

    PubMed

    Lorenz, Christiane; Von Goetz, Natalie; Scheringer, Martin; Wormuth, Matthias; Hungerbühler, Konrad

    2011-03-01

    The rapid increase in the number of consumer products containing engineered nanoparticles (ENP) raises concerns about an appropriate risk assessment of these products. Along with toxicological data, exposure estimates are essential for assessing risk. Currently, cosmetics and personal care products (C&PCP) represent the largest ENP-containing consumer product class on the market. We analyzed factors influencing the likelihood that ENP-containing products are available to consumers. We modelled potential external exposure of German consumers, assuming a maximum possible case where only ENP-containing products are used. The distribution of exposure levels within the population due to different behavior patterns was included by using data from an extensive database on consumer behavior. Exposure levels were found to vary significantly between products and between consumers showing different behavior patterns. The assessment scheme developed here represents a basis for refined exposure modelling as soon as more specific information about ENPs in C&PCP becomes available. PMID:21417685

  7. Development of biodegradable polyurethane and bioactive glass nanoparticles scaffolds for bone tissue engineering applications.

    PubMed

    de Oliveira, Agda Aline Rocha; de Carvalho, Sandhra Maria; Leite, Maria de Fátima; Oréfice, Rodrigo Lambert; Pereira, Marivalda de Magalhães

    2012-07-01

    The development of polymer/bioactive glass has been recognized as a strategy to improve the mechanical behavior of bioactive glass-based materials. Several studies have reported systems based on bioactive glass/biopolymer composites. In this study, we developed a composite system based on bioactive glass nanoparticles (BGNP), obtained by a modified Stöber method. We also developed a new chemical route to obtain aqueous dispersive biodegradable polyurethane. The production of polyurethane/BGNP scaffolds intending to combine biocompatibility, mechanical, and physical properties in a material designed for tissue engineering applications. The composites obtained were characterized by structural, biological, and mechanical tests. The films presented 350% of deformation and the foams presented pore structure and mechanical properties adequate to support cell growth and proliferation. The materials presented good cell viability and hydroxyapatite layer formation upon immersion in simulated body fluid. PMID:22566477

  8. Engineered Protein Polymer-Gold Nanoparticle Hybrid Materials for Small Molecule Delivery

    PubMed Central

    Dai, Min; Frezzo, JA; Sharma, E; Chen, R; Singh, N; Yuvienco, C; Caglar, E; Xiao, S; Saxena, A; Montclare, JK

    2016-01-01

    We have fabricated protein polymer-gold nanoparticle (P-GNP) nanocomposites that exhibit enhanced binding and delivery properties of the small hydrophobic molecule drug, curcumin, to the model breast cancer cell line, MCF-7. These hybrid biomaterials are constructed via in situ GNP templated-synthesis with genetically engineered histidine tags. The P-GNP nanocomposites exhibit enhanced small molecule loading, sustained release and increased uptake by MCF-7 cells. When compared to the proteins polymers alone, the P-GNPs demonstrate a greater than 7-fold increase in curcumin binding, a nearly 50% slower release profile and more than 2-fold increase in cellular uptake of curcumin. These results suggest that P-GNP nanocomposites serve as promising candidates for drug delivery vehicles. PMID:27081576

  9. Modulation of Hydrogel Nanoparticle Intracellular Trafficking by Multivalent Surface Engineering with Tumor Targeting Peptide†

    PubMed Central

    Karamchand, Leshern; Kim, Gwangseong; Wang, Shouyan; Hah, Hoe Jin; Ray, Aniruddha; Jiddou, Ruba; Lee, Yong-Eun Koo; Philbert, Martin A.

    2013-01-01

    Surface engineering of a hydrogel nanoparticle (NP) with the tumor-targeting ligand, F3 peptide, enhances both the NP’s binding affinity for, and internalization by, nucleolin overexpressing tumor cells. Remarkably, the F3-functionalized NPs consistently exhibited significantly lower trafficking to the degradative lysosomes than the non-functionalized NPs, in the tumor cells, after internalization. This is attributed to the non-functionalized NPs, but not the F3-functionalized NPs, being co-internalized with Lysosome-associated Membrane Protein-1 (LAMP1) from the surface of the tumor cells. Furthermore, it is shown that the intracellular trafficking of the F3-functionalized NPs differs significantly from that of the single F3 peptides. This has important implications for designing effective, chemically-responsive, controlled-release and multifunctional nanodrugs for multi-drug-resistant cancers. PMID:24056573

  10. Modulation of hydrogel nanoparticle intracellular trafficking by multivalent surface engineering with tumor targeting peptide.

    PubMed

    Karamchand, Leshern; Kim, Gwangseong; Wang, Shouyan; Hah, Hoe Jin; Ray, Aniruddha; Jiddou, Ruba; Koo Lee, Yong-Eun; Philbert, Martin A; Kopelman, Raoul

    2013-11-01

    Surface engineering of a hydrogel nanoparticle (NP) with the tumor-targeting ligand, F3 peptide, enhances both the NP's binding affinity for, and internalization by, nucleolin overexpressing tumor cells. Remarkably, the F3-functionalized NPs consistently exhibited significantly lower trafficking to the degradative lysosomes than the non-functionalized NPs, in the tumor cells, after internalization. This is attributed to the non-functionalized NPs, but not the F3-functionalized NPs, being co-internalized with Lysosome-associated Membrane Protein-1 (LAMP1) from the surface of the tumor cells. Furthermore, it is shown that the intracellular trafficking of the F3-functionalized NPs differs significantly from that of the molecular F3 peptides (untethered to NPs). This has important implications for designing effective, chemically-responsive, controlled-release and multifunctional nanodrugs for multi-drug-resistant cancers. PMID:24056573

  11. Airborne Oceanographic Lidar (AOL) (Global Carbon Cycle)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This bimonthly contractor progress report covers the operation, maintenance and data management of the Airborne Oceanographic Lidar and the Airborne Topographic Mapper. Monthly activities included: mission planning, sensor operation and calibration, data processing, data analysis, network development and maintenance and instrument maintenance engineering and fabrication.

  12. Novel magnetic fibrin hydrogel scaffolds containing thrombin and growth factors conjugated iron oxide nanoparticles for tissue engineering

    PubMed Central

    Ziv-Polat, Ofra; Skaat, Hadas; Shahar, Abraham; Margel, Shlomo

    2012-01-01

    Novel tissue-engineered magnetic fibrin hydrogel scaffolds were prepared by the interaction of thrombin-conjugated iron oxide magnetic nanoparticles with fibrinogen. In addition, stabilization of basal fibroblast growth factor (bFGF) was achieved by the covalent and physical conjugation of the growth factor to the magnetic nanoparticles. Adult nasal olfactory mucosa (NOM) cells were seeded in the transparent fibrin scaffolds in the absence or presence of the free or conjugated bFGF-iron oxide nanoparticles. The conjugated bFGF enhanced significantly the growth and differentiation of the NOM cells in the fibrin scaffolds, compared to the same or even five times higher concentration of the free bFGF. In the presence of the bFGF-conjugated magnetic nanoparticles, the cultured NOM cells proliferated and formed a three-dimensional interconnected network composed mainly of tapered bipolar cells. The magnetic properties of these matrices are due to the integration of the thrombin- and bFGF-conjugated magnetic nanoparticles within the scaffolds. The magnetic properties of these scaffolds may be used in future work for various applications, such as magnetic resonance visualization of the scaffolds after implantation and reloading the scaffolds via magnetic forces with bioactive agents, eg, growth factors bound to the iron oxide magnetic nanoparticles. PMID:22419873

  13. Nanoreinforcement of poly(propylene fumarate)-based networks with surface modified alumoxane nanoparticles for bone tissue engineering.

    PubMed

    Horch, R Adam; Shahid, Naureen; Mistry, Amit S; Timmer, Mark D; Mikos, Antonios G; Barron, Andrew R

    2004-01-01

    A novel composite material has been fabricated for bone tissue engineering scaffolds utilizing the biodegradable polymer poly(propylene fumarate)/poly(propylene fumarate)-diacrylate (PPF/PPF-DA) and surface-modified carboxylate alumoxane nanoparticles. Various surface-modified nanoparticles were added to the polymer including a surfactant alumoxane, an activated alumoxane, a mixed alumoxane containing both activated and surfactant groups, and a hybrid alumoxane containing both groups within the same substituent. These nanocomposites, as well as polymer resin and unmodified boehmite composites, underwent flexural and compressive mechanical testing and were examined using electron microscopy. Hybrid alumoxane nanoparticles dispersed in PPF/PPF-DA exhibited over a 3-fold increase in flexural modulus at 1 wt % loading compared to polymer resin alone. No significant loss of flexural or compressive strength was observed with increased loading of hybrid alumoxane nanoparticles. These dramatic improvements in flexural properties may be attributed to the fine dispersion of nanoparticles into the polymer and increased covalent interaction between polymer chains and surface modifications of nanoparticles. PMID:15360315

  14. Methodological considerations for using umu assay to assess photo-genotoxicity of engineered nanoparticles.

    PubMed

    Cupi, Denisa; Baun, Anders

    2016-01-15

    In this study we investigated the feasibility of high-throughput (96-well plate) umu assay to test the genotoxic effect of TiO2 engineered nanoparticles (ENPs) under UV light (full spectrum) and visible light (455 nm). Exposure of TiO2 ENPs to up to 60 min of UV light induced a photocatalytic production of ROS. However, UV light itself caused cytotoxic damage to Salmonella typhimurium at exposures >15 min and a genotoxic effect at exposures >0.5 min; and use of UV filters did not lower this effect. No genotoxicity of TiO2 ENPs was observed under visible light conditions at concentrations up to 100 μg mL(-1); or under dark conditions at concentrations up to 667 μg mL(-1), though cytotoxicity was seen at the higher concentrations. Additionally, the growth factor calculation was influenced by a shading effect due to ENPs, and was corrected by considering the pre-incubation OD readings of Plate B. Recommendations provided in this paper, as well as investigation of the effect of the light sources should be considered when using the umu assay to quantify the photo-genotoxicity of engineered nanomaterials. PMID:26778507

  15. Review of key factors controlling engineered nanoparticle transport in porous media.

    PubMed

    Wang, Mei; Gao, Bin; Tang, Deshan

    2016-11-15

    Nanotechnology, an emerging technology, has witnessed rapid development in production and application. Engineered nanomaterials revolutionize the industry due to their unique structure and superior performance. The release of engineered nanoparticles (ENPs) into the environment, however, may pose risks to the environment and public health. To advance current understanding of environmental behaviors of ENPs, this work provides an introductory overview of ENP fate and transport in porous media. It systematically reviews the key factors controlling their fate and transport in porous media. It first provides a brief overview of common ENPs in the environment and their sources. The key factors that govern ENP transport in porous media are then categorized into three groups: (1) nature of ENPs affecting their transport in porous media, (2) nature of porous media affecting ENP transport, and (3) nature of flow affecting ENP transport in porous media. In each group, findings in recent literature on the specific governing factors of ENP transport in porous media are discussed in details. Finally, this work concludes with remarks on the importance of ENP transport in porous media and directions for future research. PMID:27427890

  16. Gastrointestinal biodurability of engineered nanoparticles: Development of an in vitro assay

    PubMed Central

    WIECINSKI, PAIGE N.; METZ, KEVIN M.; MANGHAM, ANDREW N.; JACOBSON, KURT H.; HAMERS, ROBERT J.; PEDERSEN, JOEL A.

    2013-01-01

    The toxicity of engineered nanoparticles is expected to depend in part on their stability in biological systems. To assess the biodurability of engineered nanomaterials in the human digestive system, we adapted an in vitro assay previously used to evaluate the bioaccessibility of metals in contaminated soils. The compositions of the simulated gastric and intestinal fluids, temperature and residence times were designed to closely mimic conditions in the stomach and duodenum of the small intestine. We demonstrated the utility of the assay using CdSecore/ZnSshell quantum dots functionalized with polyethylene glycol (PEG) thiol of two different molecular masses (PEG350 and PEG5000). Under gastric conditions, removal of the PEG ligand diminished the stability of PEG350-quantum dot suspensions, while PEG5000-quantum dots were severely degraded. Inclusion of the glycoprotein mucin, but not the digestive protein pepsin, in simulated gastric fluids provided both PEG350- and PEG5000-coated quantum dots partial protection from transformations induced by gastric conditions. PMID:25197315

  17. Gelatin nanoparticles loaded poly(ε-caprolactone) nanofibrous semi-synthetic scaffolds for bone tissue engineering.

    PubMed

    Binulal, N S; Natarajan, Amrita; Menon, Deepthy; Bhaskaran, V K; Mony, Ullas; Nair, S V

    2012-12-01

    Nanofibrous semi-synthetic polymeric nanocomposite scaffolds were engineered by incorporating a maximum of 15 wt% biopolymeric gelatin nanoparticles (nGs) into the synthetic polymer poly(ε-caprolactone) (PCL) prior to electrospinning. The effect of nGs in altering the physico-chemical properties, cell material interaction and biodegradability of the scaffolds was evaluated. Experimental results showed that the inherent hydrophobicity of PCL scaffolds remained unaltered even after the incorporation of hydrophilic nGs. However, breakdown of the continuous nanofibers into lengths less than 7 µm occurred within four to eight weeks in the presence of nGs in contrast with the greater than two year time frame for the degradation of PCL fibers alone that is known from the literature. In terms of cell-material interaction, human mesenchymal stem cells (hMSCs) were found to attach and spread better and faster on PCL_nG scaffolds compared to PCL scaffolds. However, there was no difference in hMSC proliferation and differentiation into osteogenic lineage between the scaffolds. These results indicate that PCL_nG nanofibrous nanocomposite scaffolds are an improvement over PCL scaffolds for bone tissue engineering applications in that the PCL_nG scaffolds provide improved cell interaction and are able to degrade and resorb more efficiently. PMID:23047255

  18. Alteration of the Nonsystemic Behavior of the Pesticide Ferbam on Tea Leaves by Engineered Gold Nanoparticles.

    PubMed

    Hou, Ruyan; Zhang, Zhiyun; Pang, Shintaro; Yang, Tianxi; Clark, John M; He, Lili

    2016-06-21

    A model system consisting of a nonsystemic pesticide (ferbam), engineered gold nanoparticles (AuNPs) and a plant tissue (tea leaves) was investigated using surface enhanced Raman spectroscopy (SERS). Ferbam has no ability by itself to penetrate into tea leaves. When AuNPs were placed with ferbam onto the surface of tea leaves, however, the SERS signal of the ferbam-AuNPs complex was observed inside of the tea leaves. Within 1 h, the ferbam-AuNPs complex rapidly penetrated into the leaf to a depth of approximately 190 μm, about (1)/3 to (1)/2 of the leaf's thickness. The rate of penetration was dependent on the size of AuNPs, with 30 nm AuNPs-ferbam penetrating more rapidly when compared with complexes made with the 50 and 69 nm AuNPs. These results clearly demonstrated an alteration of the nonsystemic behavior of ferbam in the combined presence with AuNPs. This finding might lead to the development of some new pesticide formulations. Conversely, new toxicity issues may arise as the behaviors and fate of pesticides are altered significantly upon interaction with engineered NPs in the pesticide formulation or environment. PMID:27254832

  19. Tunable T1 and T2 contrast abilities of manganese-engineered iron oxide nanoparticles through size control

    NASA Astrophysics Data System (ADS)

    Huang, Guoming; Li, Hui; Chen, Jiahe; Zhao, Zhenghuan; Yang, Lijiao; Chi, Xiaoqin; Chen, Zhong; Wang, Xiaomin; Gao, Jinhao

    2014-08-01

    In this paper, we demonstrate the tunable T1 and T2 contrast abilities of engineered iron oxide nanoparticles with high performance for liver contrast-enhanced magnetic resonance imaging (MRI) in mice. To enhance the diagnostic accuracy of MRI, large numbers of contrast agents with T1 or T2 contrast ability have been widely explored. The comprehensive investigation of high-performance MRI contrast agents with controllable T1 and T2 contrast abilities is of high importance in the field of molecular imaging. In this study, we synthesized uniform manganese-doped iron oxide (MnIO) nanoparticles with controllable size from 5 to 12 nm and comprehensively investigated their MRI contrast abilities. We revealed that the MRI contrast effects of MnIO nanoparticles are highly size-dependent. By controlling the size of MnIO nanoparticles, we can achieve T1-dominated, T2-dominated, and T1-T2 dual-mode MRI contrast agents with much higher contrast enhancement than the corresponding conventional iron oxide nanoparticles.In this paper, we demonstrate the tunable T1 and T2 contrast abilities of engineered iron oxide nanoparticles with high performance for liver contrast-enhanced magnetic resonance imaging (MRI) in mice. To enhance the diagnostic accuracy of MRI, large numbers of contrast agents with T1 or T2 contrast ability have been widely explored. The comprehensive investigation of high-performance MRI contrast agents with controllable T1 and T2 contrast abilities is of high importance in the field of molecular imaging. In this study, we synthesized uniform manganese-doped iron oxide (MnIO) nanoparticles with controllable size from 5 to 12 nm and comprehensively investigated their MRI contrast abilities. We revealed that the MRI contrast effects of MnIO nanoparticles are highly size-dependent. By controlling the size of MnIO nanoparticles, we can achieve T1-dominated, T2-dominated, and T1-T2 dual-mode MRI contrast agents with much higher contrast enhancement than the

  20. Smart Cancer Cell Targeting Imaging and Drug Delivery System by Systematically Engineering Periodic Mesoporous Organosilica Nanoparticles.

    PubMed

    Lu, Nan; Tian, Ying; Tian, Wei; Huang, Peng; Liu, Ying; Tang, Yuxia; Wang, Chunyan; Wang, Shouju; Su, Yunyan; Zhang, Yunlei; Pan, Jing; Teng, Zhaogang; Lu, Guangming

    2016-02-10

    The integration of diagnosis and therapy into one nanoplatform, known as theranostics, has attracted increasing attention in the biomedical areas. Herein, we first present a cancer cell targeting imaging and drug delivery system based on engineered thioether-bridged periodic mesoporous organosilica nanoparticles (PMOs). The PMOs are stably and selectively conjugated with near-infrared fluorescence (NIRF) dye Cyanine 5.5 (Cy5.5) and anti-Her2 affibody on the outer surfaces to endow them with excellent NIRF imaging and cancer targeting properties. Also, taking the advantage of the thioether-group-incorporated mesopores, the release of chemotherapy drug doxorubicin (DOX) loaded in the PMOs is responsive to the tumor-related molecule glutathione (GSH). The drug release percentage reaches 84.8% in 10 mM of GSH solution within 24 h, which is more than 2-fold higher than that without GSH. In addition, the drug release also exhibits pH-responsive, which reaches 53.6% at pH 5 and 31.7% at pH 7.4 within 24 h. Confocal laser scanning microscopy and flow cytometry analysis demonstrate that the PMOs-based theranostic platforms can efficiently target to and enter Her2 positive tumor cells. Thus, the smart imaging and drug delivery nanoplatforms induce high tumor cell growth inhibition. Meanwhile, the Cy5.5 conjugated PMOs perform great NIRF imaging ability, which could monitor the intracellular distribution, delivery and release of the chemotherapy drug. In addition, cell viability and histological assessments show the engineered PMOs have good biocompatibility, further encouraging the following biomedical applications. Over all, the systemically engineered PMOs can serve as a novel cancer cell targeting imaging and drug delivery platform with NIRF imaging, GSH and pH dual-responsive drug release, and high tumor cell targeting ability. PMID:26767305

  1. Onboard measurements of nanoparticles from a SCR-equipped marine diesel engine.

    PubMed

    Hallquist, Åsa M; Fridell, Erik; Westerlund, Jonathan; Hallquist, Mattias

    2013-01-15

    In this study nanoparticle emissions have been characterized onboard a ship with focus on number, size, and volatility. Measurements were conducted on one of the ship's four main 12,600 kW medium-speed diesel engines which use low sulfur marine residual fuel and have a Selective Catalytic Reduction (SCR) system for NO(X) abatement. The particles were measured after the SCR with an engine exhaust particle sizer spectrometer (EEPS), giving particle number and mass distributions in the size range of 5.6-560 nm. The thermal characteristics of the particles were analyzed using a volatility tandem DMA system (VTDMA). A dilution ratio of 450-520 was used which is similar to the initial real-world dilution. At a stable engine load of 75% of the maximum rated power, and after dilution and cooling of the exhaust gas, there was a bimodal number size distribution, with a major peak at ∼10 nm and a smaller peak at around 30-40 nm. The mass distribution peaked around 20 nm and at 50-60 nm. The emission factor for particle number, EF(PN), for an engine load of 75% in the open-sea was found to be 10.4 ± 1.6 × 10(16) (kg fuel)(-1) and about 50% of the particles by number were found to have a nonvolatile core at 250 °C. Additionally, 20 nm particles consist of ∼40% of nonvolatile material by volume (evaporative temperature 250 °C), while the particles with a particle diameter <10 nm evaporate completely at a temperature of 130-150 °C. Emission factors for NO(X), CO, and CO(2) for an engine load of 75% in the open-sea were determined to 4.06 ± 0.3 g (kg fuel)(-1), 2.15 ± 0.06 g (kg fuel)(-1), and 3.23 ± 0.08 kg (kg fuel)(-1), respectively. This work contributes to an improved understanding of particle emissions from shipping using modern pollution reduction measures such as SCR and fuel with low sulfur content. PMID:23163334

  2. Safety and efficacy of composite collagen-silver nanoparticle hydrogels as tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Alarcon, Emilio I.; Udekwu, Klas I.; Noel, Christopher W.; Gagnon, Luke B.-P.; Taylor, Patrick K.; Vulesevic, Branka; Simpson, Madeline J.; Gkotzis, Spyridon; Islam, M. Mirazul; Lee, Chyan-Jang; Richter-Dahlfors, Agneta; Mah, Thien-Fah; Suuronen, Erik J.; Scaiano, Juan C.; Griffith, May

    2015-11-01

    The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and other inflammation markers (CCL24, sTNFR-2, and TIMP1). Finally, an analysis of silver contents in implanted mice showed that silver accumulation primarily occurred within the tissue surrounding the implant.The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and

  3. Characterizing the Transport of a Novel, Engineered Nanoparticle for Use in Remediation of Hydrophobic Contaminants

    NASA Astrophysics Data System (ADS)

    Sanders, J. E.; Miller, G. R.

    2015-12-01

    Magnetic shell crosslinked knedel-like nanoparticles (MSCKs) were originally engineered to aid in the cleanup of oil spills. These polymeric particles are spherical and approximately 70 nm in diameter. MSCKs have a hydrophobic shell and hydrophilic core which encapsulates suspended iron oxide nanoparticles, rendering them magnetic. MSCKs operate like discrete surfactant packets: increasing the mobility and apparent solubility of hydrophobic species, but do so within the confines of discrete particles which can then be recovered by filtration or magnetic removal. MSCKs accomplish this via sequestration of hydrophobic species from through the hydrophilic shell and into the hydrophobic core where hydrocarbon contaminants are entropically stabilized. In batch reactor testing, MSCKs have been shown to sequester crude oil up to ten times their mass (1000 mg of oil per 100 mg of MSCKs). This study examines the transport characteristics and contaminant sequestration capabilities of MSCKs in saturated porous media, in order to establish their potential for use in groundwater remediation. Baseline MSCK transport parameters were determined via one dimensional impulse column experiments. MSCKs were readily transported in saturated sand, with an average recovery rate of 99%. In the presence of 10% clay particles, recovery was reduced to 68%. MSCKs were able to completely sequester an aqueous phase pollutant (8.7 mg/L m-xylene), although it further reduced their recovery rate to 61% in sand and 53% in clay. The presence of a free phase contaminant (5% of pore space occupied by mineral oil) reduced MSCKs recovery in sand to 53%. The MSCKs recovered in the effluent had sequestered the mineral at ratios far below their capability (3-10 mg of oil per 100 mg of MSCKs). Overall, this study indicated that MSCKs show a number of promising attributes for use in remediation. However, further manipulation of their chemical and morphological properties is needed, with the objective of

  4. High-Throughput Screening Platform for Engineered Nanoparticle-Mediated Genotoxicity Using CometChip Technology

    PubMed Central

    2015-01-01

    The likelihood of intentional and unintentional engineered nanoparticle (ENP) exposure has dramatically increased due to the use of nanoenabled products. Indeed, ENPs have been incorporated in many useful products and have enhanced our way of life. However, there are many unanswered questions about the consequences of nanoparticle exposures, in particular, with regard to their potential to damage the genome and thus potentially promote cancer. In this study, we present a high-throughput screening assay based upon the recently developed CometChip technology, which enables evaluation of single-stranded DNA breaks, abasic sites, and alkali-sensitive sites in cells exposed to ENPs. The strategic microfabricated, 96-well design and automated processing improves efficiency, reduces processing time, and suppresses user bias in comparison to the standard comet assay. We evaluated the versatility of this assay by screening five industrially relevant ENP exposures (SiO2, ZnO, Fe2O3, Ag, and CeO2) on both suspension human lymphoblastoid (TK6) and adherent Chinese hamster ovary (H9T3) cell lines. MTT and CyQuant NF assays were employed to assess cellular viability and proliferation after ENP exposure. Exposure to ENPs at a dose range of 5, 10, and 20 μg/mL induced dose-dependent increases in DNA damage and cytotoxicity. Genotoxicity profiles of ZnO > Ag > Fe2O3 > CeO2 > SiO2 in TK6 cells at 4 h and Ag > Fe2O3 > ZnO > CeO2 > SiO2 in H9T3 cells at 24 h were observed. The presented CometChip platform enabled efficient and reliable measurement of ENP-mediated DNA damage, therefore demonstrating the efficacy of this powerful tool in nanogenotoxicity studies. PMID:24617523

  5. Poly-adenine-based programmable engineering of gold nanoparticles for highly regulated spherical DNAzymes

    NASA Astrophysics Data System (ADS)

    Zhu, Dan; Pei, Hao; Chao, Jie; Su, Shao; Aldalbahi, Ali; Rahaman, Mostafizur; Wang, Lihua; Wang, Lianhui; Huang, Wei; Fan, Chunhai; Zuo, Xiaolei

    2015-11-01

    Enzyme complexes are assembled at the two-dimensional lipid membrane or prearranged on three-dimensional scaffolding proteins to regulate their catalytic activity in cells. Inspired by nature, we have developed gold nanoparticle-based spherical DNAzymes (SNAzymes) with programmably engineered activities by exploiting poly-adenine (polyA)-Au interactions. In a SNAzyme, AuNPs serve as the metal core, which is decorated with a functional shell of DNAzymes. Conventional thiolated DNAzyme-based assembly leads to disordered structures with suppressed activity. In contrast, by using an anchoring block of polyA tails, we find that the activity of SNAzymes can be programmably regulated. By using a polyA30 tail, SNAzymes demonstrated remarkably enhanced binding affinity compared to the thiolated DNAzyme-based assembly (~75-fold) or individual DNAzymes in the solution phase (~10-fold). More significantly, this increased affinity is directly translated to the sensitivity improvement in the SNAzyme-based lead sensor. Hence, this design of SNAzymes may provide new opportunities for developing biosensors and bioimaging probes for theranostic applications.Enzyme complexes are assembled at the two-dimensional lipid membrane or prearranged on three-dimensional scaffolding proteins to regulate their catalytic activity in cells. Inspired by nature, we have developed gold nanoparticle-based spherical DNAzymes (SNAzymes) with programmably engineered activities by exploiting poly-adenine (polyA)-Au interactions. In a SNAzyme, AuNPs serve as the metal core, which is decorated with a functional shell of DNAzymes. Conventional thiolated DNAzyme-based assembly leads to disordered structures with suppressed activity. In contrast, by using an anchoring block of polyA tails, we find that the activity of SNAzymes can be programmably regulated. By using a polyA30 tail, SNAzymes demonstrated remarkably enhanced binding affinity compared to the thiolated DNAzyme-based assembly (~75-fold) or

  6. Modulation of hydrogel nanoparticle intracellular trafficking by multivalent surface engineering with tumor targeting peptide

    NASA Astrophysics Data System (ADS)

    Karamchand, Leshern; Kim, Gwangseong; Wang, Shouyan; Hah, Hoe Jin; Ray, Aniruddha; Jiddou, Ruba; Koo Lee, Yong-Eun; Philbert, Martin A.; Kopelman, Raoul

    2013-10-01

    Surface engineering of a hydrogel nanoparticle (NP) with the tumor-targeting ligand, F3 peptide, enhances both the NP's binding affinity for, and internalization by, nucleolin overexpressing tumor cells. Remarkably, the F3-functionalized NPs consistently exhibited significantly lower trafficking to the degradative lysosomes than the non-functionalized NPs, in the tumor cells, after internalization. This is attributed to the non-functionalized NPs, but not the F3-functionalized NPs, being co-internalized with Lysosome-associated Membrane Protein-1 (LAMP1) from the surface of the tumor cells. Furthermore, it is shown that the intracellular trafficking of the F3-functionalized NPs differs significantly from that of the molecular F3 peptides (untethered to NPs). This has important implications for designing effective, chemically-responsive, controlled-release and multifunctional nanodrugs for multi-drug-resistant cancers.Surface engineering of a hydrogel nanoparticle (NP) with the tumor-targeting ligand, F3 peptide, enhances both the NP's binding affinity for, and internalization by, nucleolin overexpressing tumor cells. Remarkably, the F3-functionalized NPs consistently exhibited significantly lower trafficking to the degradative lysosomes than the non-functionalized NPs, in the tumor cells, after internalization. This is attributed to the non-functionalized NPs, but not the F3-functionalized NPs, being co-internalized with Lysosome-associated Membrane Protein-1 (LAMP1) from the surface of the tumor cells. Furthermore, it is shown that the intracellular trafficking of the F3-functionalized NPs differs significantly from that of the molecular F3 peptides (untethered to NPs). This has important implications for designing effective, chemically-responsive, controlled-release and multifunctional nanodrugs for multi-drug-resistant cancers. Electronic supplementary information (ESI) available: Effect of Potassium depletion on F3 peptide subcellular localization, MTT

  7. Effects of Laser Printer–Emitted Engineered Nanoparticles on Cytotoxicity, Chemokine Expression, Reactive Oxygen Species, DNA Methylation, and DNA Damage: A Comprehensive in Vitro Analysis in Human Small Airway Epithelial Cells, Macrophages, and Lymphoblasts

    PubMed Central

    Pirela, Sandra V.; Miousse, Isabelle R.; Lu, Xiaoyan; Castranova, Vincent; Thomas, Treye; Qian, Yong; Bello, Dhimiter; Kobzik, Lester; Koturbash, Igor; Demokritou, Philip

    2015-01-01

    Background Engineered nanomaterials (ENMs) incorporated into toner formulations of printing equipment become airborne during consumer use. Although information on the complex physicochemical and toxicological properties of both toner powders and printer-emitted particles (PEPs) continues to grow, most toxicological studies have not used the actual PEPs but rather have primarily used raw toner powders, which are not representative of current exposures experienced at the consumer level during printing. Objectives We assessed the biological responses of a panel of human cell lines to PEPs. Methods Three physiologically relevant cell lines—small airway epithelial cells (SAECs), macrophages (THP-1 cells), and lymphoblasts (TK6 cells)—were exposed to PEPs at a wide range of doses (0.5–100 μg/mL) corresponding to human inhalation exposure durations at the consumer level of 8 hr or more. Following treatment, toxicological parameters reflecting distinct mechanisms were evaluated. Results PEPs caused significant membrane integrity damage, an increase in reactive oxygen species (ROS) production, and an increase in pro-inflammatory cytokine release in different cell lines at doses equivalent to exposure durations from 7.8 to 1,500 hr. Furthermore, there were differences in methylation patterns that, although not statistically significant, demonstrate the potential effects of PEPs on the overall epigenome following exposure. Conclusions The in vitro findings obtained in this study suggest that laser printer–emitted engineered nanoparticles may be deleterious to lung cells and provide preliminary evidence of epigenetic modifications that might translate to pulmonary disorders. Citation Pirela SV, Miousse IR, Lu X, Castranova V, Thomas T, Qian Y, Bello D, Kobzik L, Koturbash I, Demokritou P. 2016. Effects of laser printer–emitted engineered nanoparticles on cytotoxicity, chemokine expression, reactive oxygen species, DNA methylation, and DNA damage: a comprehensive in

  8. Energy Migration Engineering of Bright Rare-Earth Upconversion Nanoparticles for Excitation by Light-Emitting Diodes.

    PubMed

    Zhong, Yeteng; Rostami, Iman; Wang, Zihua; Dai, Hongjie; Hu, Zhiyuan

    2015-11-01

    A novel Nd(3+) -sensitized upconversion nanoparticle (UCNP) that can be excited by near-infrared 740 nm light-emitting diode (LED) lamps with bright upconversion luminescence is designed. Yb(3+) ion distribution is engineered to increase the energy migration efficiency. The benefit of the novel LED-excited UCNPs is demonstrated by imaging of breast cancer cells and enabling an economic handheld semiquantitative visual measurement device. PMID:26393770

  9. Layer-by-layer assembled multilayers and polymeric nanoparticles for drug delivery in tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Mehrotra, Sumit

    Tissues and organs in vivo are structured in three dimensional (3-D) ordered assemblies to maintain their metabolic functions. In the case of an injury, certain tissues lack the regenerative abilities without an external supportive environment. In order to regenerate the natural in vivo environment post-injury, there is a need to design three-dimensional (3-D) tissue engineered constructs of appropriate dimensions along with strategies that can deliver growth factors or drugs at a controlled rate from such constructs. This thesis focuses on the applications of hydrogen bonded (H-bonded) nanoscale layer-by-layer (LbL) assembled multilayers for time controlled drug delivery, fabrication of polymeric nanoparticles as drug delivery carriers, and engineering 3-D cellular constructs. Axonal regeneration in the central nervous system after spinal cord injury is often disorganized and random. To support linear axonal growth into spinal cord lesion sites, certain growth factors, such as brain-derived neurotrophic factor (BDNF), needs to be delivered at a controlled rate from an array of uniaxial channels patterned in a scaffold. In this study, we demonstrate for the first time that H-bonded LbL assembled degradable thin films prepared over agarose hydrogel, whereby the protein was loaded separately from the agarose fabrication, provided sustained release of protein under physiological conditions for more than four weeks. Further, patterned agarose scaffolds implanted at the site of a spinal cord injury forms a reactive cell layer of leptomeningeal fibroblasts in and around the scaffold. This limits the ability of axons to reinnervate the spinal cord. To address this challenge, we demonstrate the time controlled release of an anti-mitotic agent from agarose hydrdgel to control the growth of the reactive cell layer of fibroblasts. Challenges in tissue engineering can also be addressed using gene therapy approaches. Certain growth factors in the body are known to inhibit

  10. Composite hydrogel of chitosan-poly(hydroxybutyrate-co-valerate) with chondroitin sulfate nanoparticles for nucleus pulposus tissue engineering.

    PubMed

    Nair, Manitha B; Baranwal, Gaurav; Vijayan, Prajuna; Keyan, Kripa S; Jayakumar, R

    2015-12-01

    Intervertebral disc degeneration, occurring mainly in nucleus pulposus (NP), is a leading cause of low back pain. In seeking to mitigate this condition, investigators in the field of NP tissue engineering have increasingly studied the use of hydrogels. However, these hydrogels should possess appropriate mechanical strength and swelling pressure, and concurrently support the proliferation of chondrocyte-like cells. The objective of this study was to develop and validate a composite hydrogel for NP tissue engineering, made of chitosan-poly(hydroxybutyrate-co-valerate) (CP) with chondroitin sulfate (CS) nanoparticles, without using a cross linker. The water uptake ability, as well as the viscoelastic properties of this composite hydrogel, was similar to native tissue, as reflected in the complex shear modulus and stress relaxation values. The hydrogel could withstand varying stress corresponding to daily activities like lying down (0.01 MPa), sitting (0.5 MPa) and standing (1.0 MPa) under dynamic conditions. The hydrogels were stable in PBS for 2 weeks and its stiffness, elastic and viscous modulus did not alter significantly during this period. Both CP and CP-CS hydrogels could assist the viability and adhesion of adipose derived rat mesenchymal stem cells (ADMSCs). The viability and chondrogenic differentiation of MSCs was significantly enhanced in presence of CS nanoparticles. Thus, CS nanoparticles-incorporated chitosan-PHBV hydrogels offer great potential for NP tissue engineering. PMID:26363270

  11. A Novel Nanoparticle-Enhanced Photoacoustic Stimulus for Bone Tissue Engineering

    PubMed Central

    Avti, Pramod K.; Schaefer, Kenneth; Talukdar, Yahfi; Longtin, Jon P.

    2011-01-01

    In this study, we introduce a novel nanoparticle-enhanced biophysical stimulus based on the photoacoustic (PA) effect. We demonstrate that the PA effect differentiates bone marrow-derived marrow stromal cells (MSCs) grown on poly(lactic-co-glycolic acid) (PLGA) polymer films toward osteoblasts. We further show that the osteodifferentiation of the MSCs due to PA stimulation is significantly enhanced by the presence of single-walled carbon nanotubes (SWCNTs) in the polymer. MSCs, without the osteogenic culture supplements (0.01 M β-glycerophosphate, 50 mg/L ascorbic acid, 10−8 M dexamethasone), were seeded onto plain glass slides, glass slides coated with PLGA, or glass slides coated with SWCNT-PLGA films and photoacoustically stimulated by a 527 nm Nd:YLF pulse laser, with a 200 ns pulse duration, and 10 Hz pulse frequency for 10 min a day for 15 consecutive days. The study had four control groups; three baseline controls similar to the three experimental groups but without PA stimulation, and one positive control where MSCs were grown on glass slides without PA stimulation but with osteogenic culture supplements. The osteogenic differentiation of all the groups was evaluated using quantitative assays (alkaline phosphatase, calcium, osteopontin) and qualitative staining (alizarin red). After 15 days, the PA stimulated groups showed up to a 350% increase in calcium content when compared with the non-PA stimulated positive control. Further, within the PA stimulated group, the PLGA-SWCNT group had 130% higher calcium values than the PLGA film without SWCNTs. These results were further corroborated by the analysis of osteopontin secretion, alkaline phosphatase expression, and qualitative alizarin red staining of extracellular matrix calcification. The results indicate that PA stimulation holds promise for bone tissue engineering and that the nanomaterials which enhance the PA effect should allow the development of biophysical rather than biochemical

  12. Green rust nanoparticle formation, stability and oxidation, and its role in natural and engineered systems

    NASA Astrophysics Data System (ADS)

    Shaw, S.; Benning, L.; Ahmed, I.; Kakonyi, G.; Sumoondur, A.; Terrill, N.

    2009-12-01

    Highly reactive green rust (GR) nanoparticles are believed to play an important role in the geochemistry of water saturated sediments (e.g. hydromorphic soils) and engineered systems where zero-valent iron is used for decontaminating polluted sites (e.g. permeable reactive barriers). The presence of structural Fe2+ within GR and its high specific surface area make it an effective reductant for many inorganic (e.g. Cr, U, Se) and organic substances (e.g. tetrachloroethene (TCE)). These reduction processes can lead to breakdown of organic molecules or the formation of insoluble reduced inorganic phases (e.g., UO2(s)), thus reducing the bioavailability of these toxic compounds. Understanding the formation and geochemical stability of GR is key to assessing its potential role in natural sediments and engineered environments. However, characterizing GR is difficult due to the rapid oxidation (seconds - minutes) of structural Fe2+ in the presence of air. Thus, to obtain detailed information about the mechanism and kinetics of GR formation, stabilisation and oxidative breakdown, novel synchrotron-based methods have been developed which combine in situ and time-resolved X-ray diffraction/scattering (XRD/SAXS) analysis with controlled anaerobic chemical synthesis. This system allowed the simultaneous quantification of several chemical parameters in the aqueous solution (i.e., pH, Eh) with detailed analysis of the changes in the solid phase crystal structure. In conjunction with this X-ray Absorption Spectroscopy (XAS) was used to characterise the speciation of trace elements (i.e. U, Zn and Se) associated with GR as it crystallised and/or transformed. The formation of green rust (Fe2+/Fe3+ > 1.2) from solution occurs via a 3 stage process. The first stage is the nucleation and growth of ferric hydroxysulfate (schwertmannite) nanoparticles (~5 nm). With increasing pH the schwertmannite transforms into nanogoethite particles (< 50 nm). This process is catalyzed by adsorbed Fe

  13. Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi.

    PubMed

    Navarro, Enrique; Baun, Anders; Behra, Renata; Hartmann, Nanna B; Filser, Juliane; Miao, Ai-Jun; Quigg, Antonietta; Santschi, Peter H; Sigg, Laura

    2008-07-01

    Developments in nanotechnology are leading to a rapid proliferation of new materials that are likely to become a source of engineered nanoparticles (ENPs) to the environment, where their possible ecotoxicological impacts remain unknown. The surface properties of ENPs are of essential importance for their aggregation behavior, and thus for their mobility in aquatic and terrestrial systems and for their interactions with algae, plants and, fungi. Interactions of ENPs with natural organic matter have to be considered as well, as those will alter the ENPs aggregation behavior in surface waters or in soils. Cells of plants, algae, and fungi possess cell walls that constitute a primary site for interaction and a barrier for the entrance of ENPs. Mechanisms allowing ENPs to pass through cell walls and membranes are as yet poorly understood. Inside cells, ENPs might directly provoke alterations of membranes and other cell structures and molecules, as well as protective mechanisms. Indirect effects of ENPs depend on their chemical and physical properties and may include physical restraints (clogging effects), solubilization of toxic ENP compounds, or production of reactive oxygen species. Many questions regarding the bioavailability of ENPs, their uptake by algae, plants, and fungi and the toxicity mechanisms remain to be elucidated. PMID:18461442

  14. Thyrotropin-Releasing Hormone Loaded and Chitosan Engineered Polymeric Nanoparticles: Towards Effective Delivery of Neuropeptides.

    PubMed

    Kaur, Sarabjit; Bhararia, Avani; Sharma, Krishna; Mittal, Sherry; Jain, Rahul; Wangoo, Nishima; Sharma, Rohit K

    2016-05-01

    Thyrotropin-Releasing Hormone (TRH), a tripeptide amide with molecular formula L-pGlu-L-His-L- Pro-NH2, is used in the treatment of brain/spinal injury and certain central nervous system (CNS) disorders, including schizophrenia, Alzheimer's disease, epilepsy, depression, shock and ischemia due to its profound effects on the CNS. However, TRH's therapeutic activity is severely hampered because of instability and hydrophilicity owing to its peptidic nature which results into ineffective penetration into the blood brain barrier. In the present study, we report the synthesis and stability studies of novel chitosan engineered TRH encapsulated poly(lactide-co-glycolide) (PLGA) based nanoformulation. The aim of such an encapsulation is to allow effective delivery of TRH in biological systems as the peptidase degrade naked TRH. The synthesis of TRH was carried out manually in solution phase followed by its encapsulation using PLGA to form polymeric nanoparticles (NPs) via nanoprecipitation technique. Different parameters such as type of organic phase, concentration of stabilizer, ratio of organic phase and aqueous phase, rate of addition of organic phase were optimized, tested and evaluated for particle size, encapsulation efficiency, and stability of NPs. The TRH-PLGA NPs were then surface modified with chitosan to achieve positive surface charge rendering them potential membrane penetrating agents. PLGA, PLGA-TRH, Chitosan-PLGA and Chitosan-PLGA-TRH NPs were characterized and analyzed using Dynamic Light Scattering (DLS), Transmissiom Electron Microscopy (TEM) and Infra-red spectroscopic techniques. PMID:27483926

  15. Stability studies of commercial ZnO engineered nanoparticles in domestic wastewater

    NASA Astrophysics Data System (ADS)

    Chaúque, E. F. C.; Zvimba, J. N.; Ngila, J. C.; Musee, N.

    Most wastewater treatment plants (WWTPs) employ activated sludge processes to treat wastewater. The bacteria found in these systems degrade organic matter but are very sensitive to toxic compounds such as heavy metals, among others. The impact of emerging contaminants, such as engineered nanoparticles (ENPs) on the treatment efficiency of WWTPs is yet to be fully elucidated. The effects of physicochemical parameters; the pH and ionic strength on ZnO ENPs in domestic wastewater were investigated to establish their fate and behavior in wastewater treatment systems, as well as potential release into the environment if they pass untreated. Our findings showed a decrease in zinc concentration in the filtrate as pH and ionic strength increased which indicated its possible removal through the abiotic, biosorption, and biosolid settling mechanisms. This phenomenon was further confirmed by transmission electron microscopy (TEM) images which showed agglomerates of ZnO ENPs in wastewater compared with de-ionized water. The dynamic light scattering (DLS) analysis of ZnO ENPs suspension in the wastewater showed their stability over a period of 2 h, with energy dispersive X-ray (EDS) analysis showing the presence of zinc on the sludge surface, while X-ray diffraction (XRD) analysis confirmed the presence of ZnO ENPs in the sludge over typical wastewater pH ranges. The results of this study will inform the integrated water management on the impact of nanotechnology based industries and the best approach in handling wastewater treatment products.

  16. Toxicity Assessment of Silica Coated Iron Oxide Nanoparticles and Biocompatibility Improvement by Surface Engineering

    PubMed Central

    Malvindi, Maria Ada; De Matteis, Valeria; Galeone, Antonio; Brunetti, Virgilio; Anyfantis, George C.; Athanassiou, Athanassia; Cingolani, Roberto; Pompa, Pier Paolo

    2014-01-01

    We have studied in vitro toxicity of iron oxide nanoparticles (NPs) coated with a thin silica shell (Fe3O4/SiO2 NPs) on A549 and HeLa cells. We compared bare and surface passivated Fe3O4/SiO2 NPs to evaluate the effects of the coating on the particle stability and toxicity. NPs cytotoxicity was investigated by cell viability, membrane integrity, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) assays, and their genotoxicity by comet assay. Our results show that NPs surface passivation reduces the oxidative stress and alteration of iron homeostasis and, consequently, the overall toxicity, despite bare and passivated NPs show similar cell internalization efficiency. We found that the higher toxicity of bare NPs is due to their stronger in-situ degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. Our results indicate that surface engineering of Fe3O4/SiO2 NPs plays a key role in improving particles stability in biological environments reducing both cytotoxic and genotoxic effects. PMID:24465736

  17. Critical assessment of models for transport of engineered nanoparticles in saturated porous media.

    PubMed

    Goldberg, Eli; Scheringer, Martin; Bucheli, Thomas D; Hungerbühler, Konrad

    2014-11-01

    To reliably assess the fate of engineered nanoparticles (ENP) in soil, it is important to understand the performance of models employed to predict vertical ENP transport. We assess the ability of seven routinely employed particle transport models (PTMs) to simulate hyperexponential (HE), nonmonotonic (NM), linearly decreasing (LD), and monotonically increasing (MI) retention profiles (RPs) and the corresponding breakthrough curves (BTCs) from soil column experiments with ENPs. Several important observations are noted. First, more complex PTMs do not necessarily perform better than simpler PTMs. To avoid applying overparameterized PTMs, multiple PTMs should be applied and the best model selected. Second, application of the selected models to simulate NM and MI profiles results in poor model performance. Third, the selected models can well-approximate LD profiles. However, because the models cannot explicitly generate LD retention, these models have low predictive power to simulate the behavior of ENPs that present LD profiles. Fourth, a term for blocking can often be accounted for by parameter variation in models that do not explicitly include a term for blocking. We recommend that model performance be analyzed for RPs and BTCs separately; simultaneous fitting to the RP and BTC should be performed only under conditions where sufficient parameter validation is possible to justify the selection of a particular model. PMID:25256358

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

    PubMed

    Tiede, Karen; Hanssen, Steffen Foss; Westerhoff, Paul; Fern, Gordon J; Hankin, Steven M; Aitken, Robert J; Chaudhry, Qasim; Boxall, Alistair B A

    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 product types on the UK market as well as release scenarios, their possible fate and behaviour in raw water and during drinking water treatment was performed. Based on the available data, all the ENPs which are likely to reach water sources were identified and categorized. Worst case concentrations of ENPs in raw water and treated drinking water, using a simple exposure model, were estimated and then qualitatively compared to available estimates for human exposure through other routes. A range of metal, metal oxide and organic-based ENPs were identified that have the potential to contaminate drinking waters. Worst case predicted concentrations in drinking waters were in the low- to sub-µg/l range and more realistic estimates were tens of ng/l or less. For the majority of product types, human exposure via drinking water was predicted to be less important than exposure via other routes. The exceptions were some clothing materials, paints and coatings and cleaning products containing Ag, Al, TiO2, Fe2O3 ENPs and carbon-based materials. PMID:25962682

  19. Development of Multifunctional Magnetic Nanoparticles for Genetic Engineering and Tracking of Neural Stem Cells.

    PubMed

    Adams, Christopher; Israel, Liron Limor; Ostrovsky, Stella; Taylor, Arthur; Poptani, Harish; Lellouche, Jean-Paul; Chari, Divya

    2016-04-01

    Genetic modification of cell transplant populations and cell tracking ability are key underpinnings for effective cell therapies. Current strategies to achieve these goals utilize methods which are unsuitable for clinical translation because of related safety issues, and multiple protocol steps adding to cost and complexity. Multifunctional magnetic nanoparticles (MNPs) offering dual mode gene delivery and imaging contrast capacity offer a valuable tool in this context. Despite their key benefits, there is a critical lack of neurocompatible and multifunctional particles described for use with transplant populations for neurological applications. Here, a systematic screen of MNPs (using a core shown to cause contrast in magnetic resonance imaging (MRI)) bearing various surface chemistries (polyethylenimine (PEI) and oxidized PEI and hybrids of oxidized PEI/alginic acid, PEI/chitosan and PEI/polyamidoamine) is performed to test their ability to genetically engineer neural stem cells (NSCs; a cell population of high clinical relevance for central nervous system disorders). It is demonstrated that gene delivery to NSCs can be safely achieved using two of the developed formulations (PEI and oxPEI/alginic acid) when used in conjunction with oscillating magnetofection technology. After transfection, intracellular particles can be detected by histological procedures with labeled cells displaying contrast in MRI (for real time cell tracking). PMID:26867130

  20. Poly-adenine-based programmable engineering of gold nanoparticles for highly regulated spherical DNAzymes.

    PubMed

    Zhu, Dan; Pei, Hao; Chao, Jie; Su, Shao; Aldalbahi, Ali; Rahaman, Mostafizur; Wang, Lihua; Wang, Lianhui; Huang, Wei; Fan, Chunhai; Zuo, Xiaolei

    2015-11-28

    Enzyme complexes are assembled at the two-dimensional lipid membrane or prearranged on three-dimensional scaffolding proteins to regulate their catalytic activity in cells. Inspired by nature, we have developed gold nanoparticle-based spherical DNAzymes (SNAzymes) with programmably engineered activities by exploiting poly-adenine (polyA)-Au interactions. In a SNAzyme, AuNPs serve as the metal core, which is decorated with a functional shell of DNAzymes. Conventional thiolated DNAzyme-based assembly leads to disordered structures with suppressed activity. In contrast, by using an anchoring block of polyA tails, we find that the activity of SNAzymes can be programmably regulated. By using a polyA30 tail, SNAzymes demonstrated remarkably enhanced binding affinity compared to the thiolated DNAzyme-based assembly (∼75-fold) or individual DNAzymes in the solution phase (∼10-fold). More significantly, this increased affinity is directly translated to the sensitivity improvement in the SNAzyme-based lead sensor. Hence, this design of SNAzymes may provide new opportunities for developing biosensors and bioimaging probes for theranostic applications. PMID:26498866

  1. Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering.

    PubMed

    Baei, Payam; Jalili-Firoozinezhad, Sasan; Rajabi-Zeleti, Sareh; Tafazzoli-Shadpour, Mohammad; Baharvand, Hossein; Aghdami, Nasser

    2016-06-01

    Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues. PMID:27040204

  2. A Chemically Polymerized Electrically Conducting Composite of Polypyrrole Nanoparticles and Polyurethane for Tissue Engineering

    PubMed Central

    Broda, Christopher R.; Lee, Jae Y.; Sirivisoot, Sirinrath; Schmidt, Christine E.; Harrison, Benjamin S.

    2011-01-01

    A variety of cell types respond to electrical stimuli, accordingly many conducting polymers (CPs) have been used as tissue engineering (TE) scaffolds, one such CP is polypyrrole (PPy). PPy is a well studied biomaterial with potential TE applications due to its electrical conductivity and many other beneficial properties. Combining its characteristics with an elastomeric material, such as polyurethane (PU), may yield a hybrid scaffold with electrical activity and significant mechanical resilience. Pyrrole was in situ polymerized within a PU emulsion mixture in weight ratios of 1:100, 1:20, 1:10 and 1:5, respectively. Morphology, electrical conductivity, mechanical properties and cytocompatibility with C2C12 myoblast cells were characterized. The polymerization resulted in a composite with a principle base of PU interspersed with an electrically percolating network of PPy nanoparticles. As the mass ratio of PPy to PU increased so did electrical conductivity of the composites. In addition, as the mass ratio of PPy to PU increased, stiffness of the composite increased while maximum elongation length decreased. Ultimate tensile strength was reduced by approximately 47% across all samples with the addition of PPy to the PU base. Cytocompatibility assay data indicated no significant cytotoxic effect from the composites. Static cellular seeding of C2C12 cells and subsequent differentiation showed myotube formation on the composite materials. PMID:21681943

  3. Airborne laser topographic mapping results

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Collins, J. G.; Link, L. E.; Swift, R. N.; Butler, M. L.

    1984-01-01

    The results of terrain mapping experiments utilizing the National Aeronautics and Space Administration (NASA) Airborne Oceanographic Lidar (AOL) over forested areas are presented. The flight tests were conducted as part of a joint NASA/U.S. Army Corps of Engineers (CE) investigation aimed at evaluating the potential of an airborne laser ranging system to provide cross-sectional topographic data on flood plains that are difficult and expensive to survey using conventional techniques. The data described in this paper were obtained in the Wolf River Basin located near Memphis, TN. Results from surveys conducted under winter 'leaves off' and summer 'leaves on' conditions, aspects of day and night operation, and data obtained from decidous and coniferous tree types are compared. Data processing techniques are reviewed. Conclusions relative to accuracy and present limitations of the AOL, and airborne lidar systems in general, to terrain mapping over forested areas are discussed.

  4. Quantitative photothermal heating and cooling measurements of engineered nanoparticles in an optical trap

    NASA Astrophysics Data System (ADS)

    Roder, Paden Bernard

    hot Brownian motion theory, we attempt to measure realistic temperatures at the surface of an optically-trapped particle while properly accounting for inhomogeneous temperature fields generated by the optical trap. In Chapter 5, this technique is then applied to measure the temperature of engineered gold- and silicon-implanted silicon nanowires to rigorously study the effect ion implantation has on silicon nanowire photothermal efficiencies. Silicon nanowire photothermal efficiencies are shown to drastically increase by implanting with gold ions and cause superheating of water of over 200 C at the trap site, suggesting potential application as agents for photothermal cancer therapies. Chapter 6 describes the hydrothermal synthesis and optical trapping of engineered YLF nanoparticles doped with Yb(III) ions. Laser tweezer experiments using the developed temperature extraction techniques and hot Brownian motion analysis show the first observation of particles undergoing recently hypothesized cold Brownian motion and local laser refrigeration in a condensed phase via anti-Stokes photoluminescence. Furthermore, YLF nanoparticles codoped with Er(III) and Yb(III) ions are also developed and their intense visible upconversion of the NIR trapping laser is used to monitor its internal lattice temperature using ratiometric thermography. The results suggest the potential of these materials to investigate kinetics and temperature sensitivity of basic cellular processes, or to act as simultaneous theranostic-hypothermia agents to identify and treat cancerous tissues. Finally, Chapter 7 presents a summary of the salient conclusions of the reported studies. The chapter concludes with a short discussion of my personal experience with being a member of a new research group and setting up the Pauzauskie laboratory.

  5. Ultra-rapid photocatalytic activity of Azadirachta indica engineered colloidal titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Sankar, Renu; Rizwana, Kadarmohideen; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

    2015-08-01

    Titanium dioxide nanoparticles were effectively synthesized from aqueous leaf extract of Azadirachta indica under pH and temperature-dependent condition. 5 mM titanium isopropoxide solution worked as a primary source for the synthesis of titanium dioxide nanoparticles. The green synthesized titanium dioxide nanoparticles were confirmed by UV-Vis spectroscopy. Fourier transform infrared spectrum of synthesized titanium dioxide nanoparticles authorized the presence of bioactive compounds in the leaf extract, which may play a role as capping and reducing agent. The high-resolution scanning electron microscopy and dynamic light scattering analyses results showed the interconnected spherical in shape titanium dioxide nanoparticles having a mean particle size of 124 nm and a zeta potential of -24 mV. Besides, the colloidal titanium dioxide nanoparticles energetically degrade the industrially harmful methyl red dye under bright sunlight.

  6. Cerebrolysin, a mixture of neurotrophic factors induces marked neuroprotection in spinal cord injury following intoxication of engineered nanoparticles from metals.

    PubMed

    Menon, Preeti Kumaran; Muresanu, Dafin Fior; Sharma, Aruna; Mössler, Herbert; Sharma, Hari Shanker

    2012-02-01

    Spinal cord injury (SCI) is the world's most disastrous disease for which there is no effective treatment till today. Several studies suggest that nanoparticles could adversely influence the pathology of SCI and thereby alter the efficacy of many neuroprotective agents. Thus, there is an urgent need to find suitable therapeutic agents that could minimize cord pathology following trauma upon nanoparticle intoxication. Our laboratory has been engaged for the last 7 years in finding suitable therapeutic strategies that could equally reduce cord pathology in normal and in nanoparticle-treated animal models of SCI. We observed that engineered nanoparticles from metals e.g., aluminum (Al), silver (Ag) and copper (Cu) (50-60 nm) when administered in rats daily for 7 days (50 mg/kg, i.p.) resulted in exacerbation of cord pathology after trauma that correlated well with breakdown of the blood-spinal cord barrier (BSCB) to serum proteins. The entry of plasma proteins into the cord leads to edema formation and neuronal damage. Thus, future drugs should be designed in such a way to be effective even when the SCI is influenced by nanoparticles. Previous research suggests that a suitable combination of neurotrophic factors could induce marked neuroprotection in SCI in normal animals. Thus, we examined the effects of a new drug; cerebrolysin that is a mixture of different neurotrophic factors e.g., brain-derived neurotrophic factor (BDNF), glial cell line derived neurotrophic factor (GDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF) and other peptide fragments to treat normal or nanoparticle-treated rats after SCI. Our observations showed that cerebrolysin (2.5 ml/kg, i.v.) before SCI resulted in good neuroprotection in normal animals, whereas nanoparticle-treated rats required a higher dose of the drug (5.0 ml/kg, i.v.) to induce comparable neuroprotection in the cord after SCI. Cerebrolysin also reduced spinal cord water content, leakage of plasma proteins

  7. Addressing the complexity of water chemistry in environmental fate modeling for engineered nanoparticles.

    PubMed

    Sani-Kast, Nicole; Scheringer, Martin; Slomberg, Danielle; Labille, Jérôme; Praetorius, Antonia; Ollivier, Patrick; Hungerbühler, Konrad

    2015-12-01

    Engineered nanoparticle (ENP) fate models developed to date - aimed at predicting ENP concentration in the aqueous environment - have limited applicability because they employ constant environmental conditions along the modeled system or a highly specific environmental representation; both approaches do not show the effects of spatial and/or temporal variability. To address this conceptual gap, we developed a novel modeling strategy that: 1) incorporates spatial variability in environmental conditions in an existing ENP fate model; and 2) analyzes the effect of a wide range of randomly sampled environmental conditions (representing variations in water chemistry). This approach was employed to investigate the transport of nano-TiO2 in the Lower Rhône River (France) under numerous sets of environmental conditions. The predicted spatial concentration profiles of nano-TiO2 were then grouped according to their similarity by using cluster analysis. The analysis resulted in a small number of clusters representing groups of spatial concentration profiles. All clusters show nano-TiO2 accumulation in the sediment layer, supporting results from previous studies. Analysis of the characteristic features of each cluster demonstrated a strong association between the water conditions in regions close to the ENP emission source and the cluster membership of the corresponding spatial concentration profiles. In particular, water compositions favoring heteroaggregation between the ENPs and suspended particulate matter resulted in clusters of low variability. These conditions are, therefore, reliable predictors of the eventual fate of the modeled ENPs. The conclusions from this study are also valid for ENP fate in other large river systems. Our results, therefore, shift the focus of future modeling and experimental research of ENP environmental fate to the water characteristic in regions near the expected ENP emission sources. Under conditions favoring heteroaggregation in these

  8. Transport and Reactivity of Engineered Nanoparticles in Partially Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Dror, I.; Yecheskel, Y.; Berkowitz, B.

    2015-12-01

    Engineered nanoparticles (ENPs) are being produced in increasing amounts and have numerous applications in a variety of products and industrial processes. The same properties that make these substances so appealing may also cause them to act as persistent and toxic pollutants. The post-use release of ENPs to the environment is inevitable and soil appears to be one of the largest sinks of these potential contaminants. To date, despite the significant attention that ENP behavior in the environment has received, only a few studies have considered the fate and transport of ENPs in partially saturated systems. Here, we report measurements on the transport and fate of three commonly used ENPs - silver (Ag), gold (Au) and zinc oxide (ZnO) - in partially saturated porous media. The results show that ENP interactions with the solid matrix and solution components affect the fate of the ENPs and their transport. The negatively charged ENPs (AgNPs and AuNPs) are shown to be mobile in sand (which is also negatively charged) under various conditions, including water saturation levels and inlet concentration, with transport behavior resembling conservative tracer movement. Various aging scenarios were considered and the interaction of AgNPs with sulfides, chlorides, and calcium ions, all of which are known to interact and change AgNP properties, are shown to affect AgNP fate; however, in some cases, the changed particles remained suspended in solution and mobile. The positively charged ZnO showed very low mobility, but when humic acid was present in the inlet solution, interactions leading to enhanced mobility were observed. The presence of humic acid also changes ENP size and surface charge, transforming them to negatively charged larger aggregates that can be transported through the sand. Finally, remobilization of particles that were retained in the porous media was also demonstrated for ZnO ENPs, indicating possible release of entrapped ENPs upon changes in solution chemistry.

  9. Physicochemical transformation and algal toxicity of engineered nanoparticles in surface water samples.

    PubMed

    Zhang, Luqing; Li, Jingyi; Yang, Kun; Liu, Jingfu; Lin, Daohui

    2016-04-01

    Most studies on the behavior and toxicity of engineered nanoparticles (NPs) have been conducted in artificial water with well-controlled conditions, which are dramatically different from natural waters with complex compositions. To better understand the fate and toxicity of NPs in the natural water environment, physicochemical transformations of four NPs (TiO2, ZnO, Ag, and carbon nanotubes (CNTs)) and their toxicities towards a unicellular green alga (Chlorella pyrenoidosa) in four fresh water and one seawater sample were investigated. Results indicated that water chemistry had profound effects on aggregation, dissolution, and algal toxicity of the NPs. The strongest homoaggregation of the NPs was associated with the highest ionic strength, but no obvious correlation was observed between the homoaggregation of NPs and pH or dissolved organic matter content of the water samples. The greatest dissolution of ZnO NPs also occurred in seawater with the highest ionic strength, while the dissolution of Ag NPs varied differently from ZnO NPs. The released Zn(2+) and especially Ag(+) mainly accounted for the algal toxicity of ZnO and Ag NPs, respectively. The NP-cell heteroagglomeration occurred generally for CNTs and Ag NPs, which contributed to the observed nanotoxicity. However, there was no significant correlation between the observed nanotoxicity and the type of NP or the water chemistry. It was thus concluded that the physicochemical transformations and algal toxicities of NPs in the natural water samples were caused by the combined effects of complex water quality parameters rather than any single influencing factor alone. These results will increase our knowledge on the fate and effects of NPs in the aquatic environment. PMID:26745398

  10. Laboratory assessment of the mobility of water-dispersed engineered nanoparticles in a red soil (Ultisol)

    NASA Astrophysics Data System (ADS)

    Wang, Dengjun; Su, Chunming; Zhang, Wei; Hao, Xiuzhen; Cang, Long; Wang, Yujun; Zhou, Dongmei

    2014-11-01

    Soils are major sinks of engineered nanoparticles (ENPs) as results of land applications of sewage sludge, accidental spills, or deliberate applications of ENPs (e.g., nano-pesticides). In this study, the transport behaviors of four widely used ENPs (i.e., titanium dioxide [TiO2], buckminsterfullerene [C60], single-walled carbon nanotube [SWNT], and elemental silver [Ag0]) were investigated in water-saturated columns packed with either a quartz sand, a red soil (Ultisol), or sand/soil mixtures with soil mass fraction (λ) from 0% to 100% at slightly acidic solution pH (4.0-5.0). The mobility of tested ENPs decreased significantly with increasing λ, which was attributed to increased surface area and/or retention sites imparted by iron oxides, clay minerals, and organic matter in the red soil. Breakthrough curves of all ENPs exhibited blocking effects (decreasing deposition rate over time) and were well-described using an unfavorable and favorable, two-site kinetic attachment model accounting for random sequential adsorption on the favorable site. Modeled maximum retention capacity and first-order attachment rate coefficient on the favorable site both increased linearly with increasing λ, suggesting that transport parameters of ENPs in natural soils may be accurately extrapolated from transport parameters in the sand/soil mixtures. In addition, the mobility of three negatively charged ENPs (C60, SWNT, and Ag0 NPs) was reversely correlated with their average hydrodynamic diameters, highlighting that the average hydrodynamic diameter of negatively charged ENPs is the dominant physicochemical characteristics controlling their mobility in the Ultisol.

  11. The effect of engineered iron nanoparticles on growth and metabolic status of marine microalgae cultures.

    PubMed

    Kadar, Eniko; Rooks, Paul; Lakey, Cara; White, Daniel A

    2012-11-15

    Synthetic zero-valent nano-iron (nZVI) compounds are finding numerous applications in environmental remediation owing to their high chemical reactivity and versatile catalytic properties. Studies were carried out to assess the effects of three types of industrially relevant engineered nZVI on phytoplankton growth, cellular micromorphology and metabolic status. Three marine microalgae (Pavlova lutheri, Isochrysis galbana and Tetraselmis suecica) were grown on culture medium fortified with the nano-Fe compounds for 23 days and subsequent alterations in their growth rate, size distribution, lipid profiles and cellular ultrastructure were assessed. The added nano Fe concentrations were either equimolar with the EDTA-Fe conventionally added to the generic f/2 medium (i.e. 1.17 × 10(-5)M), or factor 10 lower and higher, respectively. We provide evidence for the: (1) broad size distribution of nZVI particles when added to the nutrient rich f/2 media with the higher relative percentage of the smallest particles with the coated forms; (2) normal algal growth in the presence of all three types of nZVIs with standard growth rates, cellular morphology and lipid content comparable or improved when compared to algae grown on f/2 with EDTA-Fe; (3) sustained algal growth and normal physiology at nZVI levels 10 fold below that in f/2, indicating preference to nanoparticles over EDTA-Fe; (4) increased total cellular lipid content in T. suecica grown on media enriched with uncoated nZVI25, and in P. lutheri with inorganically coated nZVI(powder), when compared at equimolar exposures; (5) significant change in fatty acid composition complementing the nZVI(powder)-mediated increase in lipid content of P. lutheri; (6) a putative NP uptake mechanism is proposed for I. galbana via secretion of an extracellular matrix that binds nZVIs which then become bioavailable via phagocytotic membrane processes. PMID:23059967

  12. Engineered silica nanoparticles act as adjuvants to enhance allergic airway disease in mice

    PubMed Central

    2013-01-01

    Background With the increase in production and use of engineered nanoparticles (NP; ≤ 100 nm), safety concerns have risen about the potential health effects of occupational or environmental NP exposure. Results of animal toxicology studies suggest that inhalation of NP may cause pulmonary injury with subsequent acute or chronic inflammation. People with chronic respiratory diseases like asthma or allergic rhinitis may be even more susceptible to toxic effects of inhaled NP. Few studies, however, have investigated adverse effects of inhaled NP that may enhance the development of allergic airway disease. Methods We investigated the potential of polyethylene glycol coated amorphous silica NP (SNP; 90 nm diameter) to promote allergic airway disease when co-exposed during sensitization with an allergen. BALB/c mice were sensitized by intranasal instillation with 0.02% ovalbumin (OVA; allergen) or saline (control), and co-exposed to 0, 10, 100, or 400 μg of SNP. OVA-sensitized mice were then challenged intranasally with 0.5% OVA 14 and 15 days after sensitization, and all animals were sacrificed a day after the last OVA challenge. Blood and bronchoalveolar lavage fluid (BALF) were collected, and pulmonary tissue was processed for histopathology and biochemical and molecular analyses. Results Co-exposure to SNP during OVA sensitization caused a dose-dependent enhancement of allergic airway disease upon challenge with OVA alone. This adjuvant-like effect was manifested by significantly greater OVA-specific serum IgE, airway eosinophil infiltration, mucous cell metaplasia, and Th2 and Th17 cytokine gene and protein expression, as compared to mice that were sensitized to OVA without SNP. In saline controls, SNP exposure did cause a moderate increase in airway neutrophils at the highest doses. Conclusions These results suggest that airway exposure to engineered SNP could enhance allergen sensitization and foster greater manifestation of allergic airway disease upon

  13. Surface engineering of silica nanoparticles for oral insulin delivery: characterization and cell toxicity studies.

    PubMed

    Andreani, Tatiana; Kiill, Charlene P; de Souza, Ana Luiza R; Fangueiro, Joana F; Fernandes, Lisete; Doktorovová, Slavomira; Santos, Dario L; Garcia, Maria L; Gremião, Maria Palmira D; Souto, Eliana B; Silva, Amélia M

    2014-11-01

    The present work aimed at studying the interaction between insulin and SiNP surfaced with mucoadhesive polymers (chitosan, sodium alginate or polyethylene glycol) and the evaluation of their biocompatibility with HepG2 and Caco-2 cell lines, which mimic in vivo the target of insulin-loaded nanoparticles upon oral administration. Thus, a systematic physicochemical study of the surface-modified insulin-silica nanoparticles (Ins-SiNP) using mucoadhesive polymers has been described. The surfacing of nanoparticle involved the coating of silica nanoparticles (SiNP) with different mucoadhesive polymers, to achieve high contact between the systems and the gut mucosa to enhance the oral insulin bioavailability. SiNP were prepared by a modified Stöber method at room temperature via hydrolysis and condensation of tetraethyl orthosilicate (TEOS). Interaction between insulin and nanoparticles was assessed by differential scanning calorimetry (DSC), X-ray and Fourier-transform infrared (FTIR) studies. The high efficiency of nanoparticles' coating resulted in more stable system. FTIR spectra of insulin-loaded nanoparticles showed amide absorption bands which are characteristic of α-helix content. In general, all developed nanoparticles demonstrated high biocompatible, at the tested concentrations (50-500 μg/mL), revealing no or low toxicity in the two human cancer cell lines (HepG2 and Caco-2). In conclusion, the developed insulin-loaded SiNP surfaced with mucoadhesive polymers demonstrated its added value for oral administration of proteins. PMID:25466464

  14. Gold-plated silver nanoparticles engineered for sensitive plasmonic detection amplified by morphological changes.

    PubMed

    Hobbs, Krysten; Cathcart, Nicole; Kitaev, Vladimir

    2016-07-28

    Gold-plated silver nanoparticles have been developed to undergo morphological changes that enhance the surface plasmon resonance (SPR) sensing response. These morphological changes were realized through thin-frame gold plating that both reinforces the nanoparticle edges and enables partial silver etching upon exposure to several biological molecules, including thiols and amines. PMID:27418122

  15. p-Aminophenyl-α-D-mannopyranoside engineered lipidic nanoparticles for effective delivery of docetaxel to brain.

    PubMed

    Singh, Indu; Swami, Rajan; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

    2015-05-01

    Lipidic systems are considered to be the most promising carrier for drug delivery to brain. Metabolic substrates like carbohydrates and amino acids are able to traverse the blood-brain barrier (BBB) by specific carrier-mediated transport systems like glucose transporters present on the both luminal and abluminal side of the BBB. With this objective, the docetaxel (DTX) loaded solid lipidic nanoparticles were formulated and surface modified with a mannose derived ligand p-aminophenyl-α-D-mannopyranoside (MAN) to develop MAN conjugated lipidic nanoparticles for targeting DTX to brain. Lipidic nanoparticles were prepared using emulsification and solvent evaporation method using stearic acid as charge modifying lipid and conjugated with MAN using carbodimide coupling. These lipidic nanoparticles were successfully characterized using various techniques like DLS, TEM, DSC and FTIR spectroscopy. Cytotoxicity and cell uptake unveiled enhanced efficacy of conjugated lipidic nanoparticles. Pharmacokinetic and brain distribution studies demonstrated increased DTX concentrations using lipidic nanoparticles in brain and conjugating MAN on surface of lipidic nanoparticles further augmented the inflow of the drug to brain. Present study revealed the prospective of mannose analog, MAN-conjugated lipidic nanoparticles as efficient vehicle for anticancer drug delivery to brain. PMID:25819559

  16. Engineering the emission of light from a scanning tunneling microscope using the plasmonic modes of a nanoparticle

    NASA Astrophysics Data System (ADS)

    Le Moal, Eric; Marguet, Sylvie; Canneson, Damien; Rogez, Benoît; Boer-Duchemin, Elizabeth; Dujardin, Gérald; Teperik, Tatiana V.; Marinica, Dana-Codruta; Borisov, Andrey G.

    2016-01-01

    The inelastic tunnel current in the junction formed between the tip of a scanning tunneling microscope (STM) and the sample can electrically generate optical signals. This phenomenon is potentially of great importance for nano-optoelectronic devices. In practice, however, the properties of the emitted light are difficult to control because of the strong influence of the STM tip. In this work, we show both theoretically and experimentally that the sought-after, well-controlled emission of light from an STM tunnel junction may be achieved using a nonplasmonic STM tip and a plasmonic nanoparticle on a transparent substrate. We demonstrate that the native plasmon modes of the nanoparticle may be used to engineer the light emitted in the substrate. Both the angular distribution and intensity of the emitted light may be varied in a predictable way by choosing the excitation position of the STM tip on the particle.

  17. Experimental study of the response functions of direct-reading instruments measuring surface-area concentration of airborne nanostructured particles

    NASA Astrophysics Data System (ADS)

    Bau, Sébastien; Witschger, Olivier; Gensdarmes, François; Thomas, Dominique

    2009-05-01

    An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment to move forward our understanding of the hazards, the actual exposures in the workplace, and the limits of engineering controls and personal protective equipment with regard to NP. As a consequence, generating airborne NP with controlled properties constitutes an important challenge. In parallel, toxicological studies have been carried out, and most of them support the concept that surface-area could be a relevant metric for characterizing exposure to airborne NP [1]. To provide NP surface-area concentration measurements, some direct-reading instruments have been designed, based on attachment rate of unipolar ions to NP by diffusion. However, very few information is available concerning the performances of these instruments and the parameters that could affect their responses. In this context, our work aims at characterizing the actual available instruments providing airborne NP surface-area concentration. The instruments (a- LQ1-DC, Matter Engineering; b-AeroTrak™ 9000, TSI; c- NSAM, TSI model 3550;) are thought to be relevant for further workplace exposure characterization and monitoring. To achieve our work, an experimental facility (named CAIMAN) was specially designed, built and characterized.

  18. nanoparticles

    NASA Astrophysics Data System (ADS)

    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.

  19. Modular Fabrication of Polymer Brush Coated Magnetic Nanoparticles: Engineering the Interface for Targeted Cellular Imaging.

    PubMed

    Oz, Yavuz; Arslan, Mehmet; Gevrek, Tugce N; Sanyal, Rana; Sanyal, Amitav

    2016-08-01

    Development of efficient and rapid protocols for diversification of functional magnetic nanoparticles (MNPs) would enable identification of promising candidates using high-throughput protocols for applications such as diagnostics and cure through early detection and localized delivery. Polymer brush coated magnetic nanoparticles find use in many such applications. A protocol that allows modular diversification of a pool of parent polymer coated nanoparticles will lead to a library of functional materials with improved uniformity. In the present study, polymer brush coated parent magnetic nanoparticles obtained using reversible addition-fragmentation chain transfer (RAFT) polymerization are modified to obtain nanoparticles with different "clickable" groups. In this design, trithiocarbonate group terminated polymer brushes are "grafted from" MNPs using a catechol group bearing initiator. A postpolymerization radical exchange reaction allows installation of "clickable" functional groups like azides and maleimides on the chain ends of the polymers. Thus, modified MNPs can be functionalized using alkyne-containing and thiol-containing moieties like peptides and dyes using the alkyne-azide cycloaddition and the thiol-ene conjugation, respectively. Using the approach outlined here, a cell surface receptor targeting cyclic peptide and a fluorescent dye are attached onto nanoparticle surface. This multifunctional construct allows selective recognition of cancer cells that overexpress integrin receptors. Furthermore, the approach outlined here is not limited to the installation of azide and maleimide functional groups but can be expanded to a variety of "clickable" groups to allow nanoparticle modification using a broad range of chemical conjugations. PMID:27406320

  20. Engineering biomaterial surfaces using nanoparticle assemblies: A new paradigm for modulating cell function

    NASA Astrophysics Data System (ADS)

    Lipski, Anna Marie

    Silica nanoparticles (NP) were investigated as a surface modification medium and their impact on cell function was studied. This work has demonstrated that NP assemblies are suitable for the surface modification of both metal and polymer substrates. Additionally, important surface parameters, such as nano-roughness, charge, and chemistry, can be imparted in a predictable manner. More importantly, by varying the NP size, nano-roughness of a surface can be varied independent of chemistry. Two terminally differentiated mammalian cell types, bovine aortic endothelial cells (BAEC) and murine calvarial osteoblast-like cells (MC3T3-E1), were used to probe the effects of nano-topography on cell proliferation, metabolic activity, spreading, cytoskeletal F-actin alignment, and focal adhesion recruitment. Furthermore, the influence of nano-topography on cell migration was studied using BAEC and human fetal osteoblasts (hFOB). The results suggested that surface nano-rugosity affects cell behavior at various levels and that these effects are cell type specific; however, some clear trends were discerned with respect to F-actin alignment and cell migration. In particular, presentation of nano-features resulted in enhancement of cytoskeletal F-actin alignment along the long axis of the cells in comparison to unmodified glass. With respect to cell migration, increased nano-roughness resulted in decreased migration rates for both BAEC and hFOB. Finally, the potential of nano-rugosity as a mediator of cell differentiation was investigated by following the lineage specific differentiation of human marrow-derived mesenchymal progenitor cells (MPC) on NP-modified 316L stainless steel and titanium substrates. It was observed that NP modification enhanced the differentiation of MPC into an osteogenic lineage and that rugosity appeared to be the dominant factor in directing this differentiation. Thus, coatings composed of silica NPs presented a new paradigm that may lend themselves to

  1. Combustion synthesis and engineering nanoparticles for electronic, structural and superconductor applications. Final report, May 31, 1992--May 30, 1996

    SciTech Connect

    Stangle, G.C.; Schulze, W.A.; Amarakoon, V.R.W.

    1996-05-30

    Dense, nanocrystalline ceramic articles of doped ZrO{sub 2} (for use in solid electrolytes, oxygen sensors, electrode materials, thermal barrier coatings, etc.), BaTiO{sub 3} (for capacitor applications), and YBa{sub 2}Cu{sub 3}O{sub 7-x} (a high-temperature superconductor with uses, e.g., in magnetic flux trapping and high-speed capacitor applications) were prepared by the new nanofabrication process that has been developed in this research program. The process consists of two steps: synthesis of ceramic nanoparticles, and fabrication of dense ceramic articles that possess nanocrystalline features. The synthesis step is capable of producing 10-nanometer-diameter crystallites of doped ZrO{sub 2}, and of being scaled up to kilogram/hour production rates. The fabrication step produced dense, ultrafine-grained articles at significantly reduced sintering temperatures and times--representing a factor of 10-100 reduction in process energy requirements. The process has thus been shown to be technically feasible, while a preliminary engineering cost analysis of a pilot plant-scale version of the process indicates that it is both a cost- and an energy-efficient method of producing nanoparticles and nanocrystalline ceramics from those nanoparticles. One U.S. patent for this process has been allowed, and an additional five (continuation-in-part) applications have been filed. Technology transfer efforts have begun, through ongoing discussions with representatives from three manufacturing concerns.

  2. Application of Engineered Si Nanoparticles in Light-Induced Advanced Oxidation Remediation of a Water-Borne Model Contaminant.

    PubMed

    Iqbal, Muhammad; Purkait, Tapas K; Goss, Greg G; Bolton, James R; Gamal El-Din, Mohamed; Veinot, Jonathan G C

    2016-05-24

    Surface-engineered amphiphilic polymer-coated silicon nanoparticles (SiNPs) were employed as photocatalysts to capture and degrade a model organic contaminant (methanol) in water. This study represents the first time SiNPs have been employed in the initiation of advanced oxidation processes that are commonly used to degrade organic constituents in industrial wastewaters. The quantum yield of photocatalytic methanol oxidation and the corresponding yield factor for the generation of active OH radicals are reported. The size and surface defect dependent photocatalytic activity of SiNPs was investigated. The yield factors (η) decreased with increasing particle size and reached impressive values that exceeded that of equivalent TiO2 nanoparticle systems by 3-4 times and are comparable to the robust UV/Cl2 and UV/H2O2 systems. The higher photocatalytic efficiency of SiNPs is attributed to the combined effects of quantum confinement, effective band gap, and surface states, among which surface states play a dominant role. SiNPs provide a potentially tunable, biologically inert, and robust nanoparticle system for photocatalytic oxidation of wastewater contaminants. PMID:27078819

  3. Hybrid composites made of multiwalled carbon nanotubes functionalized with Fe3O4 nanoparticles for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Cunha, C.; Panseri, S.; Iannazzo, D.; Piperno, A.; Pistone, A.; Fazio, M.; Russo, A.; Marcacci, M.; Galvagno, S.

    2012-11-01

    A straightforward technique for functionalization of multiwalled carbon nanotubes (MWCNTs) with magnetite (Fe3O4) nanoparticles was developed. Iron oxide nanoparticles were deposited on MWCNT surfaces by a deposition-precipitation method using Fe3+/Fe2+ salts precursors in basic solution. The characterizations by HRTEM, XRD, SEM/EDX, AAS and TPR analyses confirmed the successful formation of magnetic iron oxide nanoparticles on the MWCNT surface. Fe3O4/MWCNT hybrid composites were analysed in vitro by incubation with mesenchymal stem cells for 1, 3 and 7 days, either in the presence or absence of a static magnetic field. Analysis of cell proliferation was performed by the MTT assay, quantification of cellular stress was performed by the Lactate Dehydrogenase assay and analysis of cell morphology was performed by actin immunofluorescence and scanning electron microscopy. Results demonstrate that the introduction of magnetite into the MWCNT structure increases biocompatibility of oxidized MWCNTs. In addition, the presence of a static magnetic field further increases Fe3O4/MWCNT influence on cell behaviour. These results demonstrate this novel Fe3O4/MWCNT hybrid composite has good potential for tissue engineering applications.

  4. Nanoparticles at the interface between atmosphere and hydrosphere

    NASA Astrophysics Data System (ADS)

    Baumann, T.; Huckele, S.; Niessner, R.

    2012-04-01

    In the light of increasing use of engineered nanoparticles and reports of reports of adverse effects of nanoparticles on aquatic ecosystems and possible health issues, assessment of the transport of nanoparticles is of high importance. In this study we address the transport of airborne nanoparticles through the unsaturated zone in an urban environment. Aquifers and soils are the primary filter systems to remove engineered nanoparticles. These effects are used e.g., for bank filtration. Recent flooding events, on the other hand, show the limited capacity of this filter. While engineered nanoparticles are tailored to specific applications, one has to assume that they nonetheless interact with dissolved organic matter (DOM) present in surface water and top soil in larger quantities. A coating with DOM has a stabilizing effect on most nanoparticles. Thus, a transport of engineered nanoparticles through the soil seems likely. A monitoring program was performed at the Munich vadose zone field laboratory, a shaft reaching from the top soil to the groundwater table at 10 m below the ground surface. Wet and dry deposition were collected and analyzed to assess the input function. Seepage water was collected and analyzed in nine depths to assess the transport of nanoparticles. For all samples the size distribution and the elemental composition of the particles was measured using ultrafiltration, AF4, and ICP/MS. Nanoparticles deposited during dry periods may accumulate on the plant leaves and on the top soil. Here a first interaction with organic matter occurs. Heavy rainfall after a dry period will mobilize the nanoparticles. Through cracks in the top soil, preferential flow can transport the surface modified particles to the groundwater. During winter, particles are deposited on the snow cover. Sublimation of snow may lead to relatively high concentrations in the remaining snow. Cracks in the top soil caused by freezing ease the transport of nanoparticles together with the

  5. Adsorption of doxorubicin on citrate-capped gold nanoparticles: insights into engineering potent chemotherapeutic delivery systems

    NASA Astrophysics Data System (ADS)

    Curry, Dennis; Cameron, Amanda; MacDonald, Bruce; Nganou, Collins; Scheller, Hope; Marsh, James; Beale, Stefanie; Lu, Mingsheng; Shan, Zhi; Kaliaperumal, Rajendran; Xu, Heping; Servos, Mark; Bennett, Craig; Macquarrie, Stephanie; Oakes, Ken D.; Mkandawire, Martin; Zhang, Xu

    2015-11-01

    Gold nanomaterials have received great interest for their use in cancer theranostic applications over the past two decades. Many gold nanoparticle-based drug delivery system designs rely on adsorbed ligands such as DNA or cleavable linkers to load therapeutic cargo. The heightened research interest was recently demonstrated in the simple design of nanoparticle-drug conjugates wherein drug molecules are directly adsorbed onto the as-synthesized nanoparticle surface. The potent chemotherapeutic, doxorubicin often serves as a model drug for gold nanoparticle-based delivery platforms; however, the specific interaction facilitating adsorption in this system remains understudied. Here, for the first time, we propose empirical and theoretical evidence suggestive of the main adsorption process where (1) hydrophobic forces drive doxorubicin towards the gold nanoparticle surface before (2) cation-π interactions and gold-carbonyl coordination between the drug molecule and the cations on AuNP surface facilitate DOX adsorption. In addition, biologically relevant compounds, such as serum albumin and glutathione, were shown to enhance desorption of loaded drug molecules from AuNP at physiologically relevant concentrations, providing insight into the drug release and in vivo stability of such drug conjugates.Gold nanomaterials have received great interest for their use in cancer theranostic applications over the past two decades. Many gold nanoparticle-based drug delivery system designs rely on adsorbed ligands such as DNA or cleavable linkers to load therapeutic cargo. The heightened research interest was recently demonstrated in the simple design of nanoparticle-drug conjugates wherein drug molecules are directly adsorbed onto the as-synthesized nanoparticle surface. The potent chemotherapeutic, doxorubicin often serves as a model drug for gold nanoparticle-based delivery platforms; however, the specific interaction facilitating adsorption in this system remains understudied

  6. Using flow to switch the valency of bacterial capture on engineered surfaces containing immobilized nanoparticles.

    PubMed

    Fang, Bing; Gon, Saugata; Park, Myoung-Hwan; Kumar, Kushi-Nidhi; Rotello, Vincent M; Nüsslein, Klaus; Santore, Maria M

    2012-05-22

    Toward an understanding of nanoparticle-bacterial interactions and the development of sensors and other substrates for controlled bacterial adhesion, this article describes the influence of flow on the initial stages of bacterial capture (Staphylococcus aureus) on surfaces containing cationic nanoparticles. A PEG (poly(ethylene glycol)) brush on the surface around the nanoparticles sterically repels the bacteria. Variations in ionic strength tune the Debye length from 1 to 4 nm, increasing the strength and range of the nanoparticle attractions toward the bacteria. At relatively high ionic strengths (physiological conditions), bacterial capture requires several nanoparticle-bacterial contacts, termed "multivalent capture". At low ionic strength and gentle wall shear rates (on the order of 10 s(-1)), individual bacteria can be captured and held by single surface-immobilized nanoparticles. Increasing the flow rate to 50 s(-1) causes a shift from monovalent to divalent capture. A comparison of experimental capture efficiencies with statistically determined capture probabilities reveals the initial area of bacteria-surface interaction, here about 50 nm in diameter for a Debye length κ(-1) of 4 nm. Additionally, for κ(-1) = 4 nm, the net per nanoparticle binding energies are strong but highly shear-sensitive, as is the case for biological ligand-receptor interactions. Although these results have been obtained for a specific system, they represent a regime of behavior that could be achieved with different bacteria and different materials, presenting an opportunity for further tuning of selective interactions. These finding suggest the use of surface elements to manipulate individual bacteria and nonfouling designs with precise but finite bacterial interactions. PMID:22563906

  7. Stability of engineered nanomaterials in complex aqueous matrices: Settling behaviour of CeO2 nanoparticles in natural surface waters.

    PubMed

    Van Koetsem, Frederik; Verstraete, Simon; Van der Meeren, Paul; Du Laing, Gijs

    2015-10-01

    The stability of engineered nanoparticles (ENPs) in complex aqueous matrices is a key determinant of their fate and potential toxicity towards the aquatic environment and human health. Metal oxide nanoparticles, such as CeO2 ENPs, are increasingly being incorporated into a wide range of industrial and commercial applications, which will undoubtedly result in their (unintentional) release into the environment. Hereby, the behaviour and fate of CeO2 ENPs could potentially serve as model for other nanoparticles that possess similar characteristics. The present study examined the stability and settling of CeO2 ENPs (7.3±1.4 nm) as well as Ce(3+) ions in 10 distinct natural surface waters during 7d, under stagnant and isothermal experimental conditions. Natural water samples were collected throughout Flanders (Belgium) and were thoroughly characterized. For the majority of the surface waters, a substantial depletion (>95%) of the initially added CeO2 ENPs was observed just below the liquid surface of the water samples after 7d. In all cases, the reduction was considerably higher for CeO2 ENPs than for Ce(3+) ions (<68%). A first-order kinetics model was able to describe the observed time-dependant removal of both CeO2 ENPs (R(2)≥0.998) and Ce(3+) ions (R(2)≥0.812) from the water column, at least in case notable sedimentation occurred over time. Solution-pH appeared to be a prime parameter governing nanoparticle colloidal stability. Moreover, the suspended solids (TSS) content also seemed to be an important factor affecting the settling rate and residual fraction of CeO2 ENPs as well as Ce(3+) ions in natural surface waters. Correlation results also suggest potential association and co-precipitation of CeO2 ENPs with aluminium- and iron-containing natural colloidal material. The CeO2 ENPs remained stable in dispersion in surface water characterized by a low pH, ionic strength (IS), and TSS content, indicating the eventual stability and settling behaviour of the

  8. Effect of electrolyte valency, alginate concentration and pH on engineered TiO₂ nanoparticle stability in aqueous solution.

    PubMed

    Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

    2015-12-01

    Agglomeration and disagglomeration processes are expected to play a key role on the fate of engineered nanoparticles in natural aquatic systems. These processes are investigated here in detail by studying first the stability of TiO2 nanoparticles in the presence of monovalent and divalent electrolytes at different pHs (below and above the point of zero charge of TiO2) and discussing the importance of specific divalent cation adsorption with the help of the DLVO theory as well as the importance of the nature of the counterions. Then the impact of one polysaccharide (alginate) on the stability of agglomerates formed under pH and water hardness representative of Lake Geneva environmental conditions is investigated. In these conditions the large TiO2 agglomerates (diameter>1μm) are positively charged due to Ca(2+) and Mg(2+) specific adsorption and alginate, which is negatively charged, adsorbs onto the agglomerate surface. Our results indicate that the presence of alginate at typical natural organic matter concentration (1-10 mg L(-1)) strongly modifies the TiO2 agglomerate (50 mg L(-1)) stability by inducing their partial and rapid disagglomeration. The importance of disagglomeration is found dependent on the alginate concentration with maximum of disagglomeration obtained for alginate concentration ≥8 mg L(-1) and leading to 400 nm fragments. From an environmental point of view partial restabilization of TiO2 agglomerates in the presence of alginate constitutes an important outcome. Disagglomeration will enhance their transport and residence time in aquatic systems which is an important step in the current knowledge on risk assessment associated to engineered nanoparticles. PMID:25726181

  9. Engineering novel targeted nanoparticle formulations to increase the therapeutic efficacy of conventional chemotherapeutics against multiple myeloma

    NASA Astrophysics Data System (ADS)

    Ashley, Jonathan D.

    Multiple myeloma (MM) is a hematological malignancy which results from the uncontrolled clonal expansion of plasma cells within the body. Despite recent medical advances, this disease remains largely incurable, with a median survival of ˜7 years, owing to the development of drug resistance. This dissertation will explore new advances in nanotechnology that will combine the cytotoxic effects of small molecule chemotherapeutics with the tumor targeting capabilities of nanoparticles to create novel nanoparticle formulations that exhibit enhanced therapeutic indices in the treatment of MM. First, doxorubicin was surfaced conjugated onto micellar nanoparticles via an acid labile hydrazone bond to increase the drug accumulation at the tumor. The cell surface receptor Very Late Antigen-4 (VLA-4; alpha4beta1) is expressed on cancers of hematopoietic origin and plays a vital role in the cell adhesion mediated drug resistance (CAM-DR) in MM. Therefore, VLA-4 antagonist peptides were conjugated onto the nanoparticles via a multifaceted procedure to actively target MM cells and simultaneously inhibit CAM-DR. The micellar doxorubicin nanoparticles were able to overcome CAM-DR and demonstrated improved therapeutic index relative to free doxorubicin. In addition to doxorubicin, other classes of therapeutic agents, such as proteasome inhibitors, can be incorporated in nanoparticles for improved therapeutic outcomes. Utilizing boronic acid chemistry, bortezomib prodrugs were synthesized using a reversible boronic ester bond and then incorporated into liposomes. The different boronic ester bonds that could be potentially used in the synthesis of bortezomib prodrugs were screened based on stability using isobutylboronic acid. The liposomal bortezomib nanoparticles demonstrated significant proteasome inhibition and cytotoxicity in MM cells in vitro, and dramatically reduced the non-specific toxicities associated with free bortezomib while maintaining significant tumor growth

  10. Engineering phosphopeptide-decorated magnetic nanoparticles as efficient photothermal agents for solid tumor therapy.

    PubMed

    Wu, Man; Guo, Qiaoyan; Xu, Feng; Liu, Shujun; Lu, Xuehong; Wang, Jing; Gao, Hongwen; Luo, Ping

    2016-08-15

    Due to the high therapeutic efficiency and minimum damage towards normal tissues, phototherapy has drawn a great deal of attention in recent decades. Herein, we reported the synthesis of novel phosphopeptide-decorated magnetic nanoparticles (peptide-Fe3O4 nanoparticles), and their usages in photothermal therapy against solid tumor. By using a classical coprecipitation method and a facile ligand exchange route, these peptide-Fe3O4 nanoparticles were prepared with inexpensive inhesion. Upon the irradiation of a near-infrared (NIR) light, these nanoagents exhibited great photothermal effect with high photo-stability. In vitro biocompatibility studies of these peptide-Fe3O4 nanoparticles indicated their low cytotoxicity, negligible hemolysis, and no effect on blood coagulation. As expected, 4T1 murine breast cancer cells could be effectively damaged by these light-mediated nanoagents. Significantly, animal experiments demonstrated that these nanoagents held great solid tumor ablation effect with the assistance of a NIR laser irradiation. Additional studies focused on the long-term toxicity of these nanoagents indicated their high bio-compatibility. Thus, these peptide-Fe3O4 nanoparticles could bring more opportunities to a new generation of photothermal agents in the field of biomedicine. PMID:27214146

  11. Synthesis and surface engineering of magnetic nanoparticles for environmental cleanup and pesticide residue analysis: a review.

    PubMed

    Kaur, Ranjeet; Hasan, Abshar; Iqbal, Nusrat; Alam, Samsul; Saini, Mahesh Kr; Raza, Syed Kalbe

    2014-07-01

    In recent years, water pollution and pesticide accumulation in the food chain have become a serious environmental and health hazard problem. Direct determination of these contaminants is a difficult task due to their low concentration level and the matrix interferences. Therefore, an efficient separation and preconcentration procedure is often required prior to the analysis. With the advancement in nanotechnology, various types of magnetic core-shell nanoparticles have successfully been synthesized and received considerable attention as sorbents for decontamination of diverse matrices. Magnetic core-shell nanoparticles with surface modifications have the advantages of large surface-area-to-volume ratio, high number of surface active sites, no secondary pollutant, and high magnetic properties. Due to their physicochemical properties, surface-modified magnetic core-shell nanoparticles exhibit high adsorption efficiency, high rate of removal of contaminants, and easy as well as rapid separation of adsorbent from solution via external magnetic field. Such facile separation is essential to improve the operation efficiency. In addition, reuse of nanoparticles would substantially reduce the treatment cost. In this review article, we have attempted to summarize recent studies that address the preconcentration methods of pesticide residue analysis and removal of toxic contaminants from aquatic systems using magnetic core-shell nanoparticles as adsorbents. PMID:24777942

  12. Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

    NASA Astrophysics Data System (ADS)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  13. Engineering nanoparticle and nanoring patterns for the study of molecular crystallization under nanoconfinement

    NASA Astrophysics Data System (ADS)

    Wang, Sunxi

    This dissertation focuses on generating the inorganic nanoparticle/organic nanorod hybrid nanostructures by the strategy of nanoparticle induced molecular crystallization developed by us and the new electrochemical method. We synthesize the gold nanoparticles with different sizes and functional groups and then fabricate the nanohybrids with fatty acid nanorods by spin coating method. Atomic force microscope monitors the topography of the hybrid nanostructures to help understand the underlying mechanism of the crystallization process. This successful self-assembled method could be used to fabricate nanohybrids based on seed-mediated nucleation. Also the novel "nano-flasks" have been generated by particle lithography method, which could be served for nanoconfining drug crystals and be used in high throughput screening applications.

  14. Creation of Novel Solid-Solution Alloy Nanoparticles on the Basis of Density-of-States Engineering by Interelement Fusion.

    PubMed

    Kobayashi, Hirokazu; Kusada, Kohei; Kitagawa, Hiroshi

    2015-06-16

    Currently 118 known elements are represented in the periodic table. Of these 118 elements, only about 80 elements are stable, nonradioactive, and widely available for our society. From the viewpoint of the "elements strategy", we need to make full use of the 80 elements to bring out their latent ability and create innovative materials. Furthermore, there is a strong demand that the use of rare or toxic elements be reduced or replaced while their important properties are retained. Advanced science and technology could create higher-performance materials even while replacing or reducing minor or harmful elements through the combination of more abundant elements. The properties of elements are correlated directly with their electronic states. In a solid, the magnitude of the density of states (DOS) at the Fermi level affects the physical and chemical properties. In the present age, more attention has been paid to improving the properties of materials by means of alloying elements. In particular, the solid-solution-type alloy is advantageous because the properties can be continuously controlled by tuning the compositions and/or combinations of the constituent elements. However, the majority of bulk alloys are of the phase-separated type under ambient conditions, where constituent elements are immiscible with each other. To overcome the challenge of the bulk-phase metallurgical aspects, we have focused on the nanosize effect and developed methods involving "nonequilibrium synthesis" or "a process of hydrogen absorption/desorption". We propose a new concept of "density-of-states engineering" for the design of materials having the most desirable and suitable properties by means of "interelement fusion". In this Account, we describe novel solid-solution alloys of Pd-Pt, Ag-Rh, and Pd-Ru systems in which the constituent elements are immiscible in the bulk state. The homogeneous solid-solution alloys of Pd and Pt were created from Pd core/Pt shell nanoparticles using a

  15. Low temperature thermal engineering of nanoparticle ink for flexible electronics applications

    NASA Astrophysics Data System (ADS)

    Ko, Seung Hwan

    2016-07-01

    Flexible electronics are getting a lot of attention for future electronics due to their flexibility and light weight. Flexible electronics are usually fabricated on heat sensitive flexible substrates such as plastic, fabric or even paper. Therefore, the successful fabrication of flexible electronics needs a novel low temperature process development for metal circuit patterning on flexible substrates because the traditional photolithography process usually uses multiple stages of very high temperature steps for metal deposition and patterning and corrosive chemicals. In this paper, the recent novel development based on nanoparticle ink for effective deposition and patterning of high resolution metal patterns on heat sensitive, low cost and light weight plastic substrates at low temperature and in ambient pressure without using any expensive, toxic and time consuming lithographic processes will be reviewed. Nanoparticles exhibit many remarkable characteristics that are significantly different from the bulk counter parts. Nanoparticles shows size dependent melting temperature drop due to the thermodynamics size effect. These novel thermal characteristics of nanoparticles are very important for flexible electronics fabrication process development.

  16. Exploiting Fast Exciton Diffusion in Dye-Doped Polymer Nanoparticles to Engineer Efficient Photoswitching.

    PubMed

    Trofymchuk, Kateryna; Prodi, Luca; Reisch, Andreas; Mély, Yves; Altenhöner, Kai; Mattay, Jochen; Klymchenko, Andrey S

    2015-06-18

    Photoswitching of bright fluorescent nanoparticles opens new possibilities for bioimaging with superior temporal and spatial resolution. However, efficient photoswitching of nanoparticles is hard to achieve using Förster resonance energy transfer (FRET) to a photochromic dye, because the particle size is usually larger than the Förster radius. Here, we propose to exploit the exciton diffusion within the FRET donor dyes to boost photoswitching efficiency in dye-doped polymer nanoparticles. To this end, we utilized bulky hydrophobic counterions that prevent self-quenching and favor communication of octadecyl rhodamine B dyes inside a polymer matrix of poly(D,L-lactide-co-glycolide). Among tested counterions, only perfluorinated tetraphenylborate that favors the exciton diffusion enables high photoswitching efficiency (on/off ratio ∼20). The switching improves with donor dye loading and requires only 0.1-0.3 wt % of a diphenylethene photochromic dye. Our nanoparticles were validated both in solution and at the single-particle level. The proposed concept paves the way to new efficient photoswitchable nanomaterials. PMID:26266601

  17. H2O2-responsive molecularly engineered polymer nanoparticles as ischemia/reperfusion-targeted nanotherapeutic agents

    NASA Astrophysics Data System (ADS)

    Lee, Dongwon; Bae, Soochan; Hong, Donghyun; Lim, Hyungsuk; Yoon, Joo Heung; Hwang, On; Park, Seunggyu; Ke, Qingen; Khang, Gilson; Kang, Peter M.

    2013-07-01

    The main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury is the overproduction of reactive oxygen species (ROS). Hydrogen peroxide (H2O2), the most abundant form of ROS produced during I/R, causes inflammation, apoptosis and subsequent tissue damages. Here, we report H2O2-responsive antioxidant nanoparticles formulated from copolyoxalate containing vanillyl alcohol (VA) (PVAX) as a novel I/R-targeted nanotherapeutic agent. PVAX was designed to incorporate VA and H2O2-responsive peroxalate ester linkages covalently in its backbone. PVAX nanoparticles therefore degrade and release VA, which is able to reduce the generation of ROS, and exert anti-inflammatory and anti-apoptotic activity. In hind-limb I/R and liver I/R models in mice, PVAX nanoparticles specifically reacted with overproduced H2O2 and exerted highly potent anti-inflammatory and anti-apoptotic activities that reduced cellular damages. Therefore, PVAX nanoparticles have tremendous potential as nanotherapeutic agents for I/R injury and H2O2-associated diseases.

  18. Tangential Flow Filtration of Colloidal Silver Nanoparticles: A "Green" Laboratory Experiment for Chemistry and Engineering Students

    ERIC Educational Resources Information Center

    Dorney, Kevin M.; Baker, Joshua D.; Edwards, Michelle L.; Kanel, Sushil R.; O'Malley, Matthew; Pavel Sizemore, Ioana E.

    2014-01-01

    Numerous nanoparticle (NP) fabrication methodologies employ "bottom-up" syntheses, which may result in heterogeneous mixtures of NPs or may require toxic capping agents to reduce NP polydispersity. Tangential flow filtration (TFF) is an alternative "green" technique for the purification, concentration, and size-selection of…

  19. Engineered Iron-Oxide-Based Nanoparticles as Enhanced T1 Contrast Agents for Efficient Tumor Imaging

    PubMed Central

    Zhou, Zijian; Wang, Lirong; Chi, Xiaoqin; Bao, Jianfeng; Yang, Lijiao; Zhao, Wenxiu; Chen, Zhong; Wang, Xiaomin; Chen, Xiaoyuan; Gao, Jinhao

    2013-01-01

    We report the design and synthesis of small-sized zwitterion-coated gadolinium-embedded iron oxide (GdIO) nanoparticles, which exhibit a strong T1 contrast effect for tumor imaging through enhanced permeation and retention effect and the ability to clear out of the body in living subjects. The combination of spin-canting effects and the collection of gadolinium species within small-sized GdIO nanoparticles led to a significantly enhanced T1 contrast effect. For example, GdIO nanoparticles with a diameter of ~4.8 nm exhibited a high r1 relaxivity of 7.85 mM−1 · S−1 and a low r2/r1 ratio of 5.24. After being coated with zwitterionic dopamine sulfonate molecules, the 4.8 nm GdIO nanoparticles showed a steady hydrodynamic diameter (~5.2 nm) in both PBS buffer and fetal bovine serum solution, indicating a low nonspecific protein absorption. This study provides a valuable strategy for the design of highly sensitive iron-oxide-based T1 contrast agents with relatively long circulation half-lives (~50 min), efficient tumor passive targeting (SKOV3, human ovarian cancer xenograft tumor as a model), and the possibility of rapid renal clearance after tumor imaging. PMID:23473444

  20. Evaluation of the Seismic Characterision of Select Engineered Nanoparticles in Saturated Glass Beads

    EPA Science Inventory

    A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline si...

  1. Lipid Exchange Envelope Penetration (LEEP) of Nanoparticles for Plant Engineering: A Universal Localization Mechanism.

    PubMed

    Wong, Min Hao; Misra, Rahul P; Giraldo, Juan P; Kwak, Seon-Yeong; Son, Youngwoo; Landry, Markita P; Swan, James W; Blankschtein, Daniel; Strano, Michael S

    2016-02-10

    Nanoparticles offer clear advantages for both passive and active penetration into biologically important membranes. However, the uptake and localization mechanism of nanoparticles within living plants, plant cells, and organelles has yet to be elucidated.1 Here, we examine the subcellular uptake and kinetic trapping of a wide range of nanoparticles for the first time, using the plant chloroplast as a model system, but validated in vivo in living plants. Confocal visible and near-infrared fluorescent microscopy and single particle tracking of gold-cysteine-AF405 (GNP-Cys-AF405), streptavidin-quantum dot (SA-QD), dextran and poly(acrylic acid) nanoceria, and various polymer-wrapped single-walled carbon nanotubes (SWCNTs), including lipid-PEG-SWCNT, chitosan-SWCNT and 30-base (dAdT) sequence of ssDNA (AT)15 wrapped SWCNTs (hereafter referred to as ss(AT)15-SWCNT), are used to demonstrate that particle size and the magnitude, but not the sign, of the zeta potential are key in determining whether a particle is spontaneously and kinetically trapped within the organelle, despite the negative zeta potential of the envelope. We develop a mathematical model of this lipid exchange envelope and penetration (LEEP) mechanism, which agrees well with observations of this size and zeta potential dependence. The theory predicts a critical particle size below which the mechanism fails at all zeta potentials, explaining why nanoparticles are critical for this process. LEEP constitutes a powerful particulate transport and localization mechanism for nanoparticles within the plant system. PMID:26760228

  2. γ-Fe2O3 nanoparticles filled polyvinyl alcohol as potential biomaterial for tissue engineering scaffold.

    PubMed

    Ngadiman, Nor Hasrul Akhmal; Idris, Ani; Irfan, Muhammad; Kurniawan, Denni; Yusof, Noordin Mohd; Nasiri, Rozita

    2015-09-01

    Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Young's modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Young's modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds. PMID:26002419

  3. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering.

    PubMed

    Le, Thi Duy Hanh; Bonani, Walter; Speranza, Giorgio; Sglavo, Vincenzo; Ceccato, Riccardo; Maniglio, Devid; Motta, Antonella; Migliaresi, Claudio

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions. PMID:26652398

  4. Effect of negatively charged cellulose nanofibers on the dispersion of hydroxyapatite nanoparticles for scaffolds in bone tissue engineering.

    PubMed

    Park, Minsung; Lee, Dajung; Shin, Sungchul; Hyun, Jinho

    2015-06-01

    Nanofibrous 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)-oxidized bacterial cellulose (TOBC) was used as a dispersant of hydroxyapatite (HA) nanoparticles in aqueous solution. The surfaces of TOBC nanofibers were negatively charged after the reaction with the TEMPO/NaBr/NaClO system at pH 10 and room temperature. HA nanoparticles were simply adsorbed on the TOBC nanofibers (HA-TOBC) and dispersed well in DI water. The well-dispersed HA-TOBC colloidal solution formed a hydrogel after the addition of gelatin, followed by crosslinking with glutaraldehyde (HA-TOBC-Gel). The chemical modification of the fiber surfaces and the colloidal stability of the dispersion solution confirmed TOBC as a promising HA dispersant. Both the Young's modulus and maximum tensile stress increased as the amount of gelatin increased due to the increased crosslinking of gelatin. In addition, the well-dispersed HA produced a denser scaffold structure resulting in the increase of the Young's modulus and maximum tensile stress. The well-developed porous structures of the HA-TOBC-Gel composites were incubated with Calvarial osteoblasts. The HA-TOBC-Gel significantly improved cell proliferation as well as cell differentiation confirming the material as a potential candidate for use in bone tissue engineering scaffolds. PMID:25910635

  5. Peptide-laden mesoporous silica nanoparticles with promoted bioactivity and osteo-differentiation ability for bone tissue engineering.

    PubMed

    Luo, Zuyuan; Deng, Yi; Zhang, Ranran; Wang, Mengke; Bai, Yanjie; Zhao, Qiang; Lyu, Yalin; Wei, Jie; Wei, Shicheng

    2015-07-01

    Combination of mesoporous silica materials and bioactive factors is a promising niche-mimetic solution as a hybrid bone substitution for bone tissue engineering. In this work, we have synthesized biocompatible silica-based nanoparticles with abundant mesoporous structure, and incorporated bone-forming peptide (BFP) derived from bone morphogenetic protein-7 (BMP-7) into the mesoporous silica nanoparticles (MSNs) to obtain a slow-release system for osteogenic factor delivery. The chemical characterization demonstrates that the small osteogenic peptide is encapsulated in the mesoporous successfully, and the nitrogen adsorption-desorption isotherms suggest that the peptide encapsulation has no influence on mesoporous structure of MSNs. In the cell experiment, the peptide-laden MSNs (p-MSNs) show higher MG-63 cell proliferation, spreading and alkaline phosphatase (ALP) activity than the bare MSNs, indicating good in vitro cytocompatibility. Simultaneously, the osteogenesis-related proteins expression and calcium mineral deposition disclose enhanced osteo-differentiation of human mesenchymal stem cells (hMSCs) under the stimulation of the p-MSNs, confirming that BFP released from MSNs could significantly promote the osteogenic differentiation of hMSCs, especially at 500μg/mL of p-MSNs concentration. The peptide-modified MSNs with better bioactivity and osteogenic differentiation make it a potential candidate as bioactive material for bone repairing, bone regeneration, and bio-implant coating applications. PMID:25969416

  6. Surface engineered nanoparticles for improved surface enhanced Raman scattering applications and method for preparing same

    DOEpatents

    Simmons, Blake A.; Talin, Albert Alec

    2009-11-27

    A method for producing metal nanoparticles that when associated with an analyte material will generate an amplified SERS spectrum when the analyte material is illuminated by a light source and a spectrum is recorded. The method for preparing the metal nanoparticles comprises the steps of (i) forming a water-in-oil microemulsion comprising a bulk oil phase, a dilute water phase, and one or more surfactants, wherein the water phase comprises a transition metal ion; (ii) adding an aqueous solution comprising a mild reducing agent to the water-in-oil microemulsion; (iii) stirring the water-in-oil microemulsion and aqueous solution to initiate a reduction reaction resulting in the formation of a fine precipitate dispersed in the water-in-oil microemulsion; and (iv) separating the precipitate from the water-in-oil microemulsion.

  7. Preparation and characterization of surface-engineered coarse microcrystalline cellulose through dry coating with silica nanoparticles.

    PubMed

    Zhou, Qun; Shi, Limin; Chattoraj, Sayantan; Sun, Changquan Calvin

    2012-11-01

    A popular grade of microcrystalline cellulose (MCC) exhibits excellent tabletability, but marginal flowability for high-speed tableting operations. Accordingly, an enhancement in flowability, while preserving its tabletability, will make it a more useful excipient in pharmaceutical tablet formulations, especially for the direct compression process. In this work, we show that surface coating by silica nanoparticles, using either a dry comilling process or simple mechanical blending, is a valid strategy for achieving the goal. The effects of milling intensity, either the number of comilling cycles or blending time, and silica loading level have been evaluated. Results show that surface deposition of 0.1% silica nanoparticles substantially improves the flowability of this grade of MCC while preserving a significant portion of its tabletability. Higher silica loading leads to better flowability, but at the cost of reduced tabletability. However, even up to 2.0% silica deposition, its tabletability remains superior. PMID:22927169

  8. Engineering of radiolabeled iron oxide nanoparticles for dual-modality imaging.

    PubMed

    Ai, Fanrong; Ferreira, Carolina A; Chen, Feng; Cai, Weibo

    2016-07-01

    Over the last decade, radiolabeled iron oxide nanoparticles have been developed as promising contrast agents for dual-modality positron emission tomography/magnetic resonance imaging (PET/MRI) or single-photon emission computed tomography/magnetic resonance imaging (SPECT/MRI). The combination of PET (or SPECT) with MRI can offer synergistic advantages for noninvasive, sensitive, high-resolution, and quantitative imaging, which is suitable for early detection of various diseases such as cancer. Here, we summarize the recent advances on radiolabeled iron oxide nanoparticles for dual-modality imaging, through the use of a variety of PET (and SPECT) isotopes by using both chelator-based and chelator-free radiolabeling techniques. WIREs Nanomed Nanobiotechnol 2016, 8:619-630. doi: 10.1002/wnan.1386. PMID:26692551

  9. Ligand Layer Engineering To Control Stability and Interfacial Properties of Nanoparticles.

    PubMed

    Schulz, Florian; Dahl, Gregor T; Besztejan, Stephanie; Schroer, Martin A; Lehmkühler, Felix; Grübel, Gerhard; Vossmeyer, Tobias; Lange, Holger

    2016-08-01

    The use of mixed ligand layers including poly(ethylene glycol)-based ligands for the functionalization of nanoparticles is a very popular strategy in the context of nanomedicine. However, it is challenging to control the composition of the ligand layer and maintain high colloidal and chemical stability of the conjugates. A high level of control and stability are crucial for reproducibility, upscaling, and safe application. In this study, gold nanoparticles with well-defined mixed ligand layers of α-methoxypoly(ethylene glycol)-ω-(11-mercaptoundecanoate) (PEGMUA) and 11-mercaptoundecanoic acid (MUA) were synthesized and characterized by ATR-FTIR spectroscopy and gel electrophoresis. The colloidal and chemical stability of the conjugates was tested by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and UV/vis spectroscopy based experiments, and their interactions with cells were analyzed by elemental analysis. We demonstrate that the alkylene spacer in PEGMUA is the key feature for the controlled synthesis of mixed layer conjugates with very high colloidal and chemical stability and that a controlled synthesis is not possible using regular PEG ligands without the alkylene spacer. With the results of our stability tests, the molecular structure of the ligands can be clearly linked to the colloidal and chemical stabilization. We expect that the underlying design principle can be generalized to improve the level of control in nanoparticle surface chemistry. PMID:27458652

  10. Control of the interparticle spacing in superparamagnetic iron oxide nanoparticle clusters by surface ligand engineering

    NASA Astrophysics Data System (ADS)

    Dan, Wang; Bingbing, Lin; Taipeng, Shen; Jun, Wu; Fuhua, Hao; Chunchao, Xia; Qiyong, Gong; Huiru, Tang; Bin, Song; Hua, Ai

    2016-07-01

    Polymer-mediated self-assembly of superparamagnetic iron oxide (SPIO) nanoparticles allows modulation of the structure of SPIO nanocrystal cluster and their magnetic properties. In this study, dopamine-functionalized polyesters (DA-polyester) were used to directly control the magnetic nanoparticle spacing and its effect on magnetic resonance relaxation properties of these clusters was investigated. Monodisperse SPIO nanocrystals with different surface coating materials (poly(ε-caprolactone), poly(lactic acid)) of different molecular weights containing dopamine (DA) structure (DA-PCL2k, DA-PCL1k, DA-PLA1k)) were prepared via ligand exchange reaction, and these nanocrystals were encapsulated inside amphiphilic polymer micelles to modulate the SPIO nanocrystal interparticle spacing. Small-angle x-ray scattering (SAXS) was applied to quantify the interparticle spacing of SPIO clusters. The results demonstrated that the tailored magnetic nanoparticle clusters featured controllable interparticle spacing providing directly by the different surface coating of SPIO nanocrystals. Systematic modulation of SPIO nanocrystal interparticle spacing can regulate the saturation magnetization (M s) and T 2 relaxation of the aggregation, and lead to increased magnetic resonance (MR) relaxation properties with decreased interparticle spacing. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB933903), the National Key Technology R&D Program of China (Grant No. 2012BAI23B08), and the National Natural Science Foundation of China (Grant Nos. 20974065, 51173117, and 50830107).

  11. Cellular uptake and intracellular fate of engineered nanoparticles: a review on the application of imaging techniques.

    PubMed

    Tantra, Ratna; Knight, Alex

    2011-09-01

    The use of imaging tools to probe nanoparticle-cell interactions will be crucial to elucidating the mechanisms of nanoparticle-induced toxicity. Of particular interest are mechanisms associated with cell penetration, translocation and subsequent accumulation inside the cell, or in cellular compartments. The objective of the present paper is to review imaging techniques that have been previously used in order to assess such interactions, and new techniques with the potential to be useful in this area. In order to identify the most suitable techniques, they were evaluated and matched against a list of evaluation criteria. We conclude that limitations exist with all of the techniques and the ultimate choice will thus depend on the needs of end users, and their particular application. The state-of-the-art techniques appear to have the least limitations, despite the fact that they are not so well established and still far from being routine. For example, super-resolution microscopy techniques appear to have many advantages for understanding the details of the interactions between nanoparticles and cells. Future research should concentrate on further developing or improving such novel techniques, to include the development of standardized methods and appropriate reference materials. PMID:20846020

  12. Engineering the Intracellular Micro- and Nano-environment via Magnetic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Tseng, Peter

    Single cells, despite being the base unit of living organisms, possess a high degree of hierarchical structure and functional compartmentalization. This complexity exists for good reason: cells must respond efficiently and effectively to its surrounding environment by differentiating, moving, interacting, and more in order to survive or inhabit its role in the larger biological system. At the core of these responses is cellular decision-making. Cells process cues internally and externally from the environment and effect intracellular asymmetry in biochemistry and structure in order to carry out the proper biological responses. Functionalized magnetic particles have shown to be a powerful tool in interacting with biological matter, through either cell or biomolecule sorting, and the activation of biological processes. This dissertation reports on techniques utilizing manipulated magnetic nanoparticles (internalized by cells) to spatially and temporally localize intracellular cues, and examines the resulting asymmetry in biological processes generated by our methods. We first examine patterned micromagnetic elements as a simple strategy of rapidly manipulating magnetic nanoparticles throughout the intracellular space. Silicon or silicon dioxide substrates form the base for electroplated NiFe rods, which are repeated at varying size and pitch. A planarizing resin, initially SU-8, is used as the substrate layer for cellular adhesion. We demonstrate that through the manipulations of a simple external magnet, these micro-fabricated substrates can mediate rapid (under 2 s) and precise (submicron), reversible translation of magnetic nanoparticles through cellular space. Seeding cells on substrates composed of these elements allows simultaneous control of ensembles of nanoparticles over thousands of cells at a time. We believe such substrates could form the basis of magnetically based tools for the activation of biological matter. We further utilize these strategies to

  13. Study of carbonaceous nanoparticles in premixed C{sub 2}H{sub 4}-air flames and behind a spark ignition engine

    SciTech Connect

    Grotheer, Horst-Henning; Hoffmann, Kai; Wolf, Katrin; Kanjarkar, Santosh; Wahl, Claus; Aigner, Manfred

    2009-04-15

    Nanoparticle size distributions and their concentrations were studied in atmospheric premixed ethylene/air flames using photo ionization mass spectrometry (PIMS) and total organic carbon (TOC) calibration supplemented by differential mobility analysis (DMA). Focus of this study is the evolution of nanoparticles as a function of height above burner (HAB) and of the C/O ratio of the unburned gases. It was found that especially particles of the cluster type exhibit a sharp concentration drop by more than two orders of magnitude within a narrow C/O window which is close to the sooting threshold. Using DMA a decline by two orders of magnitude was found. These results suggest that at best only small concentrations of nanoparticles should be formed significantly below the sooting threshold. As these conditions prevail in a homogeneously charged IC engine no or only very small nanoparticle emissions are expected in the exhaust gas. This was indeed found for a small Otto engine driving a power generator unit. Using flame nanoparticle profiles as standard, absolute concentrations for their emissions could be deduced. These data were supported by additional DMA measurements. The calibration using TOC did not completely match the one based on the condensation particle counter of the DMA apparatus. (author)

  14. Nanofibrous poly(lactide-co-glycolide) membranes loaded with diamond nanoparticles as promising substrates for bone tissue engineering

    PubMed Central

    Parizek, Martin; Douglas, Timothy EL; Novotna, Katarina; Kromka, Alexander; Brady, Mariea A; Renzing, Andrea; Voss, Eske; Jarosova, Marketa; Palatinus, Lukas; Tesarek, Pavel; Ryparova, Pavla; Lisa, Věra; dos Santos, Ana M; Bacakova, Lucie

    2012-01-01

    Background Nanofibrous scaffolds loaded with bioactive nanoparticles are promising materials for bone tissue engineering. Methods In this study, composite nanofibrous membranes containing a copolymer of L-lactide and glycolide (PLGA) and diamond nanoparticles were fabricated by an electrospinning technique. PLGA was dissolved in a mixture of methylene chloride and dimethyl formamide (2:3) at a concentration of 2.3 wt%, and nanodiamond (ND) powder was added at a concentration of 0.7 wt% (about 23 wt% in dry PLGA). Results In the composite scaffolds, the ND particles were either arranged like beads in the central part of the fibers or formed clusters protruding from the fibers. In the PLGA-ND membranes, the fibers were thicker (diameter 270 ± 9 nm) than in pure PLGA meshes (diameter 218 ± 4 nm), but the areas of pores among these fibers were smaller than in pure PLGA samples (0.46 ± 0.02 μm2 versus 1.28 ± 0.09 μm2 in pure PLGA samples). The PLGA-ND membranes showed higher mechanical resistance, as demonstrated by rupture tests of load and deflection of rupture probe at failure. Both types of membranes enabled the attachment, spreading, and subsequent proliferation of human osteoblast-like MG-63 cells to a similar extent, although these values were usually lower than on polystyrene dishes. Nevertheless, the cells on both types of membranes were polygonal or spindle-like in shape, and were distributed homogeneously on the samples. From days 1–7 after seeding, their number rose continuously, and at the end of the experiment, these cells were able to create a confluent layer. At the same time, the cell viability, evaluated by a LIVE/DEAD viability/cytotoxicity kit, ranged from 92% to 97% on both types of membranes. In addition, on PLGA-ND membranes, the cells formed well developed talin-containing focal adhesion plaques. As estimated by the determination of tumor necrosis factor-alpha levels in the culture medium and concentration of intercellular adhesion

  15. Engineering of a novel adjuvant based on lipid-polymer hybrid nanoparticles: A quality-by-design approach.

    PubMed

    Rose, Fabrice; Wern, Jeanette Erbo; Ingvarsson, Pall Thor; van de Weert, Marco; Andersen, Peter; Follmann, Frank; Foged, Camilla

    2015-07-28

    The purpose of this study was to design a novel and versatile adjuvant intended for mucosal vaccination based on biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) modified with the cationic surfactant dimethyldioctadecylammonium (DDA) bromide and the immunopotentiator trehalose-6,6'-dibehenate (TDB) (CAF01) to tailor humoral and cellular immunity characterized by antibodies and Th1/Th17 responses. Such responses are important for the protection against diseases caused by intracellular bacteria such as Chlamydia trachomatis and Mycobacterium tuberculosis. The hybrid NPs were engineered using an oil-in-water single emulsion method and a quality-by-design approach was adopted to define the optimal operating space (OOS). Four critical process parameters (CPPs) were identified, including the acetone concentration in the water phase, the stabilizer [polyvinylalcohol (PVA)] concentration, the lipid-to-total solid ratio, and the total concentration. The CPPs were linked to critical quality attributes consisting of the particle size, polydispersity index (PDI), zeta-potential, thermotropic phase behavior, yield and stability. A central composite face-centered design was performed followed by multiple linear regression analysis. The size, PDI, enthalpy of the phase transition and yield were successfully modeled, whereas the models for the zeta-potential and the stability were poor. Cryo-transmission electron microscopy revealed that the main structural effect on the nanoparticle architecture is caused by the use of PVA, and two different morphologies were identified: i) A PLGA core coated with one or several concentric lipid bilayers, and ii) a PLGA nanoshell encapsulating lipid membrane structures. The optimal formulation, identified from the OOS, was evaluated in vivo. The hybrid NPs induced antibody and Th1/Th17 immune responses that were similar in quality and magnitude to the response induced by DDA/TDB liposomes, showing that the adjuvant

  16. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The characteristics of an Airborne Oceanographic Lidar (AOL) are given. The AOL system is described and its potential for various measurement applications including bathymetry and fluorosensing is discussed.

  17. Surface strain engineering through Tb doping to study the pressure dependence of exciton-phonon coupling in ZnO nanoparticles

    SciTech Connect

    Sharma, A.; Dhar, S. Singh, B. P.; Nayak, C.; Bhattacharyya, D.; Jha, S. N.

    2013-12-07

    A compressive hydrostatic strain has been found to develop in the ZnO lattice as a result of accumulation of Tb ions on the surface of the nanoparticles for Tb mole-fraction less than 0.04. This hydrostatic strain can be controlled up to ≈14 GPa by varying the Tb mole-fraction. Here, we have utilized this novel technique of surface strain engineering through Tb doping for introducing hydrostatic compressive strain in the lattice to study the pressure dependent electronic and vibrational properties of ZnO nanoparticles. Our study reveals that when subjected to pressure, nanoparticles of ZnO behave quite differently than bulk in many aspects. Unlike bulk ZnO, which is reported to go through a wurtzite to rock-salt structural phase transition at ≈8 GPa, ZnO nanoparticles do not show such transition and remain in wurtzite phase even at 14 GPa of pressure. Furthermore, the Grüneisen parameters for the optical phonon modes are found to be order of magnitude smaller in ZnO nanoparticles as compared to bulk. Our study also suggests an increase of the dielectric constant with pressure, which is opposite to what has been reported for bulk ZnO. Interestingly, it has also been found that the exciton-phonon interaction depends strongly upon pressure in this system. The exciton-phonon coupling has been found to decrease as pressure increases. A variational technique has been adopted to theoretically calculate the exciton-LO phonon coupling coefficient in ZnO nanoparticles as a function of pressure, which shows a good agreement with the experimental results. These findings imply that surface engineering of ZnO nanoparticles with Tb could indeed be an efficient tool to enhance and control the optical performance of this material.

  18. Color-switchable, emission-enhanced fluorescence realized by engineering C-dot@C-dot nanoparticles.

    PubMed

    Guo, Zhen; Zhang, Zhiqiang; Zhang, Wei; Zhou, Lianqun; Li, Haiwen; Wang, Hongmei; Andreazza-Vignolle, Caroline; Andreazza, Pascal; Zhao, Dongxu; Wu, Yihui; Wang, Quanlong; Zhang, Tao; Jiang, Keming

    2014-12-10

    This paper reports the preparation and properties of color-switchable fluorescent carbon nanodots (C-dots). C-dots that emit dark turquoise and green-yellow fluorescence under 365 nm UV illumination were obtained from the hydrothermal decomposition of citric acid. Dark green fluorescent C-dots were obtained by conjugating prepared C-dots to form C-dot@C-dot nanoparticles. After successful conjugation of the C-dots, the fluorescence emission undergoes a blue-shift of nearly 20 nm (∼0.15 eV) under UV excitation at 370 nm. The C-dots emit goldenrod, green-yellow, and gold light under excitation at 455 nm, which shows that the prepared C-dots are color-switchable. Furthermore, conjugation of the C-dots results in enhanced, red-shifted absorption of the π-π* transition of the aromatic sp(2) domains due to the conjugated π-electron system. N incorporation in the carbon structure leads to a degree of dipoles for all the aromatic sp(2) bonds. The enhanced absorption in a wide range from 226 to 601 nm indicates extended conjugation in the C-dot@C-dot structure. The time-resolved average lifetimes for the three different types of C-dots prepared in this study are 7.10, 7.65, and 4.07 ns. The radiative rate (reduced decay lifetime) increases when the C-dots are conjugated in the C-dot@C-dot nanoparticles, leading to the enhanced fluorescence emission. The fluorescence emission of the C-dot@C-dot nanoparticles can be used in applications such as flow cytometry and cell imaging. PMID:25408428

  19. Engineering nanostructured polymer blends with controlled nanoparticle location for excellent microwave absorption: a compartmentalized approach.

    PubMed

    Biswas, Sourav; Kar, Goutam Prasanna; Bose, Suryasarathi

    2015-07-14

    In order to obtain better materials, control over the precise location of nanoparticles is indispensable. It is shown here that ordered arrangements of nanoparticles, possessing different characteristics (electrical/magnetic dipoles), in the blend structure can result in excellent microwave absorption. This is manifested from a high reflection loss of ca. -67 dB for the best blend structure designed here. To attenuate electromagnetic radiation, the key parameters of high electrical conductivity and large dielectric/magnetic loss are targeted here by including a conductive material [multiwall carbon nanotubes, MWNTs], ferroelectric nanostructured material with associated relaxations in the GHz frequency [barium titanate, BT] and lossy ferromagnetic nanoparticles [nickel ferrite, NF]. In this study, bi-continuous structures were designed using 50/50 (by wt) blends of polycarbonate (PC) and polyvinylidene fluoride (PVDF). The MWNTs were modified using an electron acceptor molecule, a derivative of perylenediimide, which facilitates π-π stacking with the nanotubes and stimulates efficient charge transport in the blends. The nanoscopic materials have specific affinity towards the PVDF phase. Hence, by introducing surface-active groups, an ordered arrangement can be tailored. To accomplish this, both BT and NF were first hydroxylated followed by the introduction of amine-terminal groups on the surface. The latter facilitated nucleophilic substitution reactions with PC and resulted in their precise location. In this study, we have shown for the first time that by a compartmentalized approach, superior EM attenuation can be achieved. For instance, when the nanoparticles were localized exclusively in the PVDF phase or in both the phases, the minimum reflection losses were ca. -18 dB (for the MWNT/BT mixture) and -29 dB (for the MWNT/NF mixture), and the shielding occurred primarily through reflection. Interestingly, by adopting the compartmentalized approach wherein the

  20. Effects of Surface-Engineered Nanoparticle-Based Dispersants for Marine Oil Spills on the Model Organism Artemia franciscana

    PubMed Central

    2015-01-01

    Fine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50–1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25–50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25–75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms. PMID:24823274

  1. Controllable degradation kinetics of POSS nanoparticle-integrated poly(ε-caprolactone urea)urethane elastomers for tissue engineering applications.

    PubMed

    Yildirimer, Lara; Buanz, Asma; Gaisford, Simon; Malins, Edward L; Remzi Becer, C; Moiemen, Naiem; Reynolds, Gary M; Seifalian, Alexander M

    2015-01-01

    Biodegradable elastomers are a popular choice for tissue engineering scaffolds, particularly in mechanically challenging settings (e.g. the skin). As the optimal rate of scaffold degradation depends on the tissue type to be regenerated, next-generation scaffolds must demonstrate tuneable degradation patterns. Previous investigations mainly focussed on the integration of more or less hydrolysable components to modulate degradation rates. In this study, however, the objective was to develop and synthesize a family of novel biodegradable polyurethanes (PUs) based on a poly(ε-caprolactone urea)urethane backbone integrating polyhedral oligomeric silsesquioxane (POSS-PCLU) with varying amounts of hard segments (24%, 28% and 33% (w/v)) in order to investigate the influence of hard segment chemistry on the degradation rate and profile. PUs lacking POSS nanoparticles served to prove the important function of POSS in maintaining the mechanical structures of the PU scaffolds before, during and after degradation. Mechanical testing of degraded samples revealed hard segment-dependent modulation of the materials' viscoelastic properties, which was attributable to (i) degradation-induced changes in the PU crystallinity and (ii) either the presence or absence of POSS. In conclusion, this study presents a facile method of controlling degradation profiles of PU scaffolds used in tissue engineering applications. PMID:26463421

  2. Effects of surface-engineered nanoparticle-based dispersants for marine oil spills on the model organism Artemia franciscana.

    PubMed

    Rodd, April L; Creighton, Megan A; Vaslet, Charles A; Rangel-Mendez, J Rene; Hurt, Robert H; Kane, Agnes B

    2014-06-01

    Fine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50-1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25-50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25-75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms. PMID:24823274

  3. Controllable degradation kinetics of POSS nanoparticle-integrated poly(ε-caprolactone urea)urethane elastomers for tissue engineering applications

    PubMed Central

    Yildirimer, Lara; Buanz, Asma; Gaisford, Simon; Malins, Edward L.; Remzi Becer, C.; Moiemen, Naiem; Reynolds, Gary M.; Seifalian, Alexander M.

    2015-01-01

    Biodegradable elastomers are a popular choice for tissue engineering scaffolds, particularly in mechanically challenging settings (e.g. the skin). As the optimal rate of scaffold degradation depends on the tissue type to be regenerated, next-generation scaffolds must demonstrate tuneable degradation patterns. Previous investigations mainly focussed on the integration of more or less hydrolysable components to modulate degradation rates. In this study, however, the objective was to develop and synthesize a family of novel biodegradable polyurethanes (PUs) based on a poly(ε-caprolactone urea)urethane backbone integrating polyhedral oligomeric silsesquioxane (POSS-PCLU) with varying amounts of hard segments (24%, 28% and 33% (w/v)) in order to investigate the influence of hard segment chemistry on the degradation rate and profile. PUs lacking POSS nanoparticles served to prove the important function of POSS in maintaining the mechanical structures of the PU scaffolds before, during and after degradation. Mechanical testing of degraded samples revealed hard segment-dependent modulation of the materials’ viscoelastic properties, which was attributable to (i) degradation-induced changes in the PU crystallinity and (ii) either the presence or absence of POSS. In conclusion, this study presents a facile method of controlling degradation profiles of PU scaffolds used in tissue engineering applications. PMID:26463421

  4. In vivo epigenetic effects induced by engineered nanomaterials: A case study of copper oxide and laser printer-emitted engineered nanoparticles.

    PubMed

    Lu, Xiaoyan; Miousse, Isabelle R; Pirela, Sandra V; Moore, Jodene K; Melnyk, Stepan; Koturbash, Igor; Demokritou, Philip

    2016-01-01

    Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs. PMID:26559097

  5. Ecotoxicity of engineered TiO2 nanoparticles to saltwater organisms: an overview.

    PubMed

    Minetto, D; Libralato, G; Volpi Ghirardini, A

    2014-05-01

    The innovative properties of nanomaterials make them suitable for various applications in many fields. In particular, TiO2 nanoparticles (nTiO2) are widely used in paints, in cosmetics and in sunscreens that are products accessible to the mass market. Despite the great increase in the use of such nanomaterials, there is a paucity of general information about their potential effects to the aquatic species, especially to saltwater ones. Moreover, the difficulties of determining the effective exposure scenario make the acquired information low comparable. In this work, questions about the complexity of the real exposure scenario determination are discussed. The state of the art, concerning the experimental activities with nTiO2 toward the saltwater organisms is firstly illustrated, providing statistical information about the different matrices, organisms and nanoparticles employed. A comparison of the nTiO2 ecotoxicity effects, grouped by taxonomic classes, is provided illustrating their relative experimental conditions. Findings show the need to develop specific protocols for toxicity tests with ENPs to control the variability of experimental conditions. Some advices are finally proposed for the future experimental activities. PMID:24509165

  6. Nanoimaging: photophysical and pharmaceutical characterization of poly-lactide-co-glycolide nanoparticles engineered with quantum dots

    NASA Astrophysics Data System (ADS)

    Pederzoli, F.; Ruozi, B.; Pracucci, E.; Signore, G.; Zapparoli, Mauro; Forni, F.; Vandelli, M. A.; Ratto, G.; Tosi, G.

    2016-01-01

    Quantum dots (QDs) and polymeric nanoparticles (NPs) are considered good binomials for the development of multifunctional nanomedicines for multimodal imaging. Fluorescent imaging of QDs can monitor the behavior of QD-labeled NPs in both cells and animals with high temporal and spatial resolutions. The comprehension of polymer interaction with the metallic QD surface must be considered to achieve a complete chemicophysical characterization of these systems and to describe the QD optical properties to be used for their unequivocal identification in the tissue. In this study, by comparing two different synthetic procedures to obtain polymeric nanoparticles labeled with QDs, we investigated whether their optical properties may change according to the formulation methods, as a consequence of the different polymeric environments. Atomic force microscopy, transmission electron microscopy, confocal and fluorescence lifetime imaging microscopy characterization demonstrated that NPs modified with QDs after the formulation process (post-NPs-QDs) conserved the photophysical features of the QD probe. In contrast, by using a polymer modified with QDs to formulate NPs (pre-NPs-QDs), a significant quenching of QD fluorescence and a blueshift in its emission spectra were observed. Our results suggest that the packaging of QDs into the polymeric matrix causes a modification of the QD optical properties: these effects must be characterized in depth and carefully considered when developing nanosystems for imaging and biological applications.

  7. COMPARATIVE IN VITRO PULMONARY TOXICITY OF ENGINEERED, MANUFACTURED, AND ENVIRONMENTAL NANOPARTICLES

    EPA Science Inventory

    Engineered nanomaterials display many unique physicochemical properties for a variety of applications and due to their novel propertiesapplications may have unique routes of exposure and toxicity. This study examines the: 1) ability of the MTT assay to generate false positives or...

  8. Comparative DNA damage and transcriptomic effects of engineered nanoparticles in human lung cells in vitro

    EPA Science Inventory

    A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), various types of DNA damage, and transcriptional changes in human respiratory BEAS-2B cells exposed in vitro at se...

  9. Hybrid Hydroxyapatite Nanoparticle Colloidal Gels are Injectable Fillers for Bone Tissue Engineering

    PubMed Central

    Gu, Zhen; Jamal, Syed; Detamore, Michael S.

    2013-01-01

    Injectable bone fillers have emerged as an alternative to the invasive surgery often required to treat bone defects. Current bone fillers may benefit from improvements in dynamic properties such as shear thinning during injection and recovery of material stiffness after placement. Negatively charged inorganic hydroxyapatite (HAp) nanoparticles (NPs) were assembled with positively charged organic poly(d,l-lactic-co-glycolic acid) (PLGA) NPs to create a cohesive colloidal gel. This material is held together by electrostatic forces that may be disrupted by shear to facilitate extrusion, molding, or injection. Scanning electron micrographs of the dried colloidal gels showed a well-organized, three-dimensional porous structure. Rheology tests revealed that certain colloidal gels could recover after being sheared. Human umbilical cord mesenchymal stem cells were also highly viable when seeded on the colloidal gels. HAp/PLGA NP colloidal gels offer an attractive scheme for injectable filling and regeneration of bone tissue. PMID:23815275

  10. Bioavailability and biological effect of engineered silver nanoparticles in a forest soil.

    PubMed

    Carbone, S; Vittori Antisari, L; Gaggia, F; Baffoni, L; Di Gioia, D; Vianello, G; Nannipieri, P

    2014-09-15

    The extensive use of silver nanoparticles (SNPs) as antimicrobial in food, clothing and medicine, leads inevitably to a loss of such nanomaterial in soil and water. Little is known about the effects of soil contamination, in particular, on microbial cells, which play a fundamental ecological role. In this work, the impact of SNPs on forest soil has been studied, investigating eco-physiological indicators of microbial biomass and microbial diversity with culture-dependent and independent techniques. Moreover, SNPs bioavailability and uptake were assessed. Soil samples were spiked with SNPs at two different concentrations (10 and 100 μg g(-1)dw) and incubated with the relative controls for 30, 60 and 90 days. The overall parameters showed a significant influence of the SNPs on the soil microbial community, revealing a marked shift after 60 days of incubation. PMID:25133850

  11. Engineered Organometallic Polymer and Hybrid Systems Containing Nanoparticles and/or Poly(ferrocenylsilanes)

    NASA Astrophysics Data System (ADS)

    Roskov, Kristen Ekiert

    Formation of polymer nanocomposites is becoming an increasingly attractive and facile means by which to combine the desirable properties of metals and metal oxides (e.g., electrical, magnetic, optical, and thermal) with those of polymers (e.g., flexible, lightweight and tough). Incorporation of nanoscale objects such as spheroidal nanoparticles or elongated nanorods into electrospun polymer nano/microfibers measuring from 50 nm to 1 mum in diameter yields functional nanomaterials that can be used in various applications ranging from data storage and conductive nanowires to nonwoven sensors, magnetic filters and drug delivery patches. By aligning nanoscale objects in one-dimensional constructs, we expect that desirable attributes arising from highly anisotropic electronic, optical, thermal, magnetic, and catalytic properties can be realized. The objective of this study is to gain a better fundamental understanding of how to controllably align and position nanoparticles and nanorods within polymer nano/microfibers to generate unique properties. To achieve this objective, we focus on four specific process strategies. In the first, superparamagnetic iron oxide nanoparticles (SPIONs) are aligned into one-dimensional nanoarrays through the use of magnetic field-assisted electrospinning. In this case, an electromagnet is positioned near the Taylor cone of the suspension to be electrospun so that the magnetic field is oriented perpendicular to the electric field. Transmission electron microscopy (TEM) is utilized to ascertain the morphology of the resultant nanocomposite fibers and reveals that the SPION nanoarrays persist intact beyond 1 mum. Since the magnetic field can be pulsed, the length of the nanoarrays can be judiciously controlled. Magnetization hysteresis curves measured on a superconducting quantum interference device yield saturation magnetization and mean magnetic moment values. Secondly, gold nanorods (GNRs) varying in aspect ratio have been flow-aligned in

  12. Surface engineering of nanoparticles in suspension for particle based bio-sensing

    NASA Astrophysics Data System (ADS)

    Sen, Tapas; Bruce, Ian J.

    2012-08-01

    Surface activation of nanoparticles in suspension using amino organosilane has been carried out via strict control of a particle surface ad-layer of water using a simple but efficient protocol `Tri-phasic Reverse Emulsion' (TPRE). This approach produced thin and ordered layers of particle surface functional groups which allowed the efficient conjugation of biomolecules. When used in bio-sensing applications, the resultant conjugates were highly efficient in the hybrid capture of complementary oligonucleotides and the detection of food borne microorganism. TPRE overcomes a number of fundamental problems associated with the surface modification of particles in aqueous suspension viz. particle aggregation, density and organization of resultant surface functional groups by controlling surface condensation of the aminosilane. The approach has potential for application in areas as diverse as nanomedicine, to food technology and industrial catalysis.

  13. Combustion synthesis and engineering of nanoparticles for electronic, structural and superconductor applications

    SciTech Connect

    Stangle, G.C.; Amarakoon, V.R.W.; Schulze, W.A.

    1993-05-28

    Fully dense, nanocrystalline ceramic articles were prepared by the new nanofabrication process. The process consists of two steps: synthesis of ceramic nanoparticles and fabrication of dense, nanocrystalline ceramic parts. The synthesis step produced 10-nanometer-diameter crystallites, and is capable of being scaled up to kilogram/hour production rates. The fabrication step produced dense parts at significantly reduced sintering temperatures and times -- representing a factor of 10--100 reduction in process energy requirements. The process was demonstrated by producing ultrafine-grained yttria-stabilized ZrO[sub 2], an important material with a variety of energy-related applications (solid electrolytes, oxygen sensors, electrode materials, thermal barrier coatings, etc.). Results from this period clearly illustrate the capabilities of this energy-efficient and directly commercializable process for producing dense, nanocrystalline, multicomponent oxide ceramics.

  14. Engineering interface and surface of noble metal nanoparticle nanotubes toward enhanced catalytic activity for fuel cell applications.

    PubMed

    Cui, Chun-Hua; Yu, Shu-Hong

    2013-07-16

    In order for fuel cells to have commercial viability as alternative fuel sources, researchers need to develop highly active and robust fuel cell electrocatalysts. In recent years, the focus has been on the design and synthesis of novel catalytic materials with controlled interface and surface structures. Another goal is to uncover potential catalytic activity and selectivity, as well as understand their fundamental catalytic mechanisms. Scientists have achieved great progress in the experimental and theoretical investigation due to the urgent demand for broad commercialization of fuel cells in automotive applications. However, there are still three main problems: cost, performance, and stability. To meet these targets, the catalyst needs to have multisynergic functions. In addition, the composition and structure changes of the catalysts during the reactions still need to be explored. Activity in catalytic nanomaterials is generally controlled by the size, shape, composition, and interface and surface engineering. As such, one-dimensional nanostructures such as nanowires and nanotubes are of special interest. However, these structures tend to lose the nanoparticle morphology and inhibit the use of catalysts in both fuel cell anodes and cathodes. In 2003, Rubinstein and co-workers proposed the idea of nanoparticle nanotubes (NNs), which combine the geometry of nanotubes and the morphology of nanoparticles. This concept gives both the high surface-to-volume ratio and the size effect, which are both appealing in electrocatalyst design. In this Account, we describe our developments in the construction of highly active NNs with unique surface and heterogeneous interface structures. We try to clarify enhanced activity and stability in catalytic systems by taking into account the activity impact factors. We briefly introduce material structural effects on the electrocatalytic reactivity including metal oxide/metal and metal/metal interfaces, dealloyed pure Pt, and mixed Pt

  15. Characterization of manufactured TiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Motzkus, C.; Macé, T.; Vaslin-Reimann, S.; Ausset, P.; Maillé, M.

    2013-04-01

    Technological advances in nanomaterials have allowed the development of new applications in industry, increasing the probability of finding airborne manufactured and engineered nano-objects in the workplace, as well as in ambient air. Scientific studies on health and environmental risks have indicated that airborne nano-objects in ambient air have potential adverse effects on the health of exposed workers and the general population. For regulatory purposes, ambient measurements of particulate matter are based on the determination of mass concentrations for PM10 and PM2.5, as regulated in the European Directive 2008/50/EC. However, this legislation is not suitable for airborne manufactured and engineered nano-objects. Parameters characterising ultrafine particles, such as particle number concentration and size distribution, are under consideration for future health-based legislation, to monitor workplaces and to control industrial processes. Currently, there are no existing regulations covering manufactured airborne nano-objects. There is therefore a clear, unaddressed need to focus on the toxicology and exposure assessment of nano-objects such as titanium dioxide (TiO2), which are manufactured and engineered in large quantities in industry. To perform reliable toxicology studies it is necessary to determine the relevant characteristics of nano-objects, such as morphology, surface area, agglomeration, chemical composition, particle size and concentration, by applying traceable methods. Manufacturing of nanomaterials, and their use in industrial applications, also require traceable characterisation of the nanomaterials, particularly for quality control of the process. The present study arises from the OECD WPMN sponsorship programme, supported by the French Agency for Environmental and Occupational Health Safety (ANSES), in order to develop analytical methods for the characterization of TiO2 nanoparticles in size and count size distribution, based on different

  16. NASA's Coastal and Ocean Airborne Science Testbed

    NASA Astrophysics Data System (ADS)

    Guild, L. S.; Dungan, J. L.; Edwards, M.; Russell, P. B.; Morrow, J. H.; Hooker, S.; Myers, J.; Kudela, R. M.; Dunagan, S.; Soulage, M.; Ellis, T.; Clinton, N. E.; Lobitz, B.; Martin, K.; Zell, P.; Berthold, R. W.; Smith, C.; Andrew, D.; Gore, W.; Torres, J.

    2011-12-01

    The Coastal and Ocean Airborne Science Testbed (COAST) Project is a NASA Earth-science flight mission that will advance coastal ecosystems research by providing a unique airborne payload optimized for remote sensing in the optically complex coastal zone. Teaming NASA Ames scientists and engineers with Biospherical Instruments, Inc. (San Diego) and UC Santa Cruz, the airborne COAST instrument suite combines a customized imaging spectrometer, sunphotometer system, and a new bio-optical radiometer package to obtain ocean/coastal/atmosphere data simultaneously in flight for the first time. The imaging spectrometer (Headwall) is optimized in the blue region of the spectrum to emphasize remote sensing of marine and freshwater ecosystems. Simultaneous measurements supporting empirical atmospheric correction of image data will be accomplished using the Ames Airborne Tracking Sunphotometer (AATS-14). Based on optical detectors called microradiometers, the NASA Ocean Biology and Biogeochemistry Calibration and Validation (cal/val) Office team has deployed advanced commercial off-the-shelf instrumentation that provides in situ measurements of the apparent optical properties at the land/ocean boundary including optically shallow aquatic ecosystems (e.g., lakes, estuaries, coral reefs). A complimentary microradiometer instrument package (Biospherical Instruments, Inc.), optimized for use above water, will be flown for the first time with the airborne instrument suite. Details of the October 2011 COAST airborne mission over Monterey Bay demonstrating this new airborne instrument suite capability will be presented, with associated preliminary data on coastal ocean color products, coincident spatial and temporal data on aerosol optical depth and water vapor column content, as well as derived exact water-leaving radiances.

  17. Genetically Engineered Plant Viral Nanoparticles Direct Neural Cells Differentiation and Orientation.

    PubMed

    Feng, Sheng; Lu, Lin; Zan, Xingjie; Wu, Yehong; Lin, Yuan; Wang, Qian

    2015-09-01

    An important aim of tissue engineering is to design biomimetic materials with specific cell binding motifs and precisely controlled structural organization, thereby providing biochemical and physical cues for desired cellular behaviors. Previously, our group generated genetically modified tobacco mosaic virus (TMV) displaying integrin binding motifs, RGD1, RGD7, PSHRN3, P15, and DGEA. The resulting rod-like virus particles displaying integrin binding motifs were biocompatible with Neuro 2A (N2a), a mouse neural crest-derived cell line, and could promote the neurite outgrowth of N2a. The genetically modified viruses could be assembled with aligned orientation in the capillary by applying a shear force. The resulting aligned substrates were able to dictate directional neurite outgrowth of N2a cells. Therefore, this method could be potentially applied for neural tissue engineering, as a neural conduit for repairing peripheral nerve injuries. PMID:26247572

  18. Thermosensitive Ion Channel Activation in Single Neuronal Cells by Using Surface-Engineered Plasmonic Nanoparticles.

    PubMed

    Nakatsuji, Hirotaka; Numata, Tomohiro; Morone, Nobuhiro; Kaneko, Shuji; Mori, Yasuo; Imahori, Hiroshi; Murakami, Tatsuya

    2015-09-28

    Controlling cell functions using external photoresponsive nanomaterials has enormous potential for the development of cell-engineering technologies and intractable disease therapies, but the former currently requires genetic modification of the target cells. We present a method using plasma-membrane-targeted gold nanorods (pm-AuNRs) prepared with a cationic protein/lipid complex to activate a thermosensitive cation channel, TRPV1, in intact neuronal cells. Highly localized photothermal heat generation mediated by the pm-AuNRs induced Ca(2+) influx solely by TRPV1 activation. In contrast, the use of previously reported cationic AuNRs that are coated with a conventional synthetic polymer also led to photoinduced Ca(2+) influx, but this influx resulted from membrane damage. Our method provides an optogenetic platform without the need for prior genetic engineering of the target cells and might be useful for novel TRPV1-targeted phototherapeutic approaches. PMID:26249533

  19. Interface of Physics and Biology: Engineering Virus-Based Nanoparticles for Biophotonics

    PubMed Central

    2015-01-01

    Virus-based nanoparticles (VNPs) have been used for a wide range of applications, spanning basic materials science and translational medicine. Their propensity to self-assemble into precise structures that offer a three-dimensional scaffold for functionalization has led to their use as optical contrast agents and related biophotonics applications. A number of fluorescently labeled platforms have been developed and their utility in optical imaging demonstrated, yet their optical properties have not been investigated in detail. In this study, two VNPs of varying architectures were compared side-by-side to determine the impact of dye density, dye localization, conjugation chemistry, and microenvironment on the optical properties of the probes. Dyes were attached to icosahedral cowpea mosaic virus (CPMV) and rod-shaped tobacco mosaic virus (TMV) through a range of chemistries to target particular side chains displayed at specific locations around the virus. The fluorescence intensity and lifetime of the particles were determined, first using photochemical experiments on the benchtop, and second in imaging experiments using tissue culture experiments. The virus-based optical probes were found to be extraordinarily robust under ultrashort, pulsed laser light conditions with a significant amount of excitation energy, maintaining structural and chemical stability. The most effective fluorescence output was achieved through dye placement at optimized densities coupled to the exterior surface avoiding conjugated ring systems. Lifetime measurements indicate that fluorescence output depends not only on spacing the fluorophores, but also on dimer stacking and configurational changes leading to radiationless relaxation—and these processes are related to the conjugation chemistry and nanoparticle shape. For biological applications, the particles were also examined in tissue culture, from which it was found that the optical properties differed from those found on the benchtop

  20. Overcoming barriers in Pseudomonas aeruginosa lung infections: Engineered nanoparticles for local delivery of a cationic antimicrobial peptide.

    PubMed

    d'Angelo, Ivana; Casciaro, Bruno; Miro, Agnese; Quaglia, Fabiana; Mangoni, Maria Luisa; Ungaro, Francesca

    2015-11-01

    Cationic antimicrobial peptides (CAMPs) are very promising in the treatment of multi-drug resistant Pseudomonas aeruginosa lung infections experienced by cystic fibrosis (CF) patients. Nevertheless, there is an urgent need of inhalable formulations able to deliver the intact CAMP in conductive airways and to shield its interactions with airway mucus/bacterial biofilm, thus enhancing CAMP/bacteria interactions. Along these lines, the aim of this work was the design and development of nano-embedded microparticles (NEM) for sustained delivery of CAMPs in the lung. To this purpose, nanoparticles (NPs) made of poly(lactide-co-glycolide) (PLGA) containing a model CAMP, colistin (Col), were produced by emulsion/solvent diffusion technique. Engineering NPs with chitosan (CS) and poly(vinyl alcohol) (PVA) allowed to modulate surface properties and, in so doing, to improve NP transport through artificial CF mucus. In order to achieve a long-term stable dosage form useful for NP inhalation, NPs were spray-dried in different carriers (lactose or mannitol), thus producing NEM. The most promising NEM formulations were selected on the basis of bulk and flow properties, distribution of NPs in the carrier and aerosolization performance upon delivery through a breath-actuated dry powder inhaler. Of note, selected Col-loaded NEM were found to kill P. aeruginosa biofilm and to display a prolonged efficacy in biofilm eradication compared to the free Col. This effect was likely ascribable to the ability of NPs to penetrate into bacterial biofilm, as demonstrated by confocal analysis, and to sustain Col release inside it. Taken all together, our results indicate that adequate engineering of PLGA NPs represents an enticing technological approach to harness novel antimicrobials for P. aeruginosa lung infection, such as CAMPs, especially in CF. PMID:26340361

  1. Engineering of Superparamagnetic Core-Shell Iron Oxide/N-Chloramine Nanoparticles for Water Purification.

    PubMed

    Haham, Hai; Natan, Michal; Gutman, Ori; Kolitz-Domb, Michal; Banin, Ehud; Margel, Shlomo

    2016-07-20

    In this study, we describe the synthesis and characterization of superparamagnetic core-shell iron oxide (IO)/N-halamine antibacterial nanoparticles (NPs). For this purpose, superparamagnetic IO core NPs were coated with cross-linked polymethacrylamide (PMAA) by surfactant-free dispersion copolymerization of methacrylamide and N,N-methylenebis(acrylamide) in an aqueous continuous phase. The effect of the polymerization process on the chemical composition, size, shape, crystallinity, and magnetic properties of the IO/PMAA NPs was elucidated. Conversion of the core-shell IO/PMAA NPs into their N-halamine form, IO/PMAA-Cl, was accomplished using a chlorination reaction with sodium hypochlorite. The influence of chlorination on the shape, crystallinity, and magnetic properties of the IO/PMAA NPs was studied. The IO/PMAA-Cl NPs demonstrated excellent antibacterial activity against Gram-negative and Gram-positive bacteria. Finally, the chlorination recharging capabilities of the NPs and their potential for use in the purification of water containing bacteria were demonstrated with magnetic columns packed with the IO/PMAA-Cl NPs. PMID:27348740

  2. Self-monitored photothermal nanoparticles based on core-shell engineering.

    PubMed

    Ximendes, Erving C; Rocha, Uéslen; Jacinto, Carlos; Kumar, Kagola Upendra; Bravo, David; López, Fernando J; Martín Rodríguez, Emma; García-Solé, José; Jaque, Daniel

    2016-02-01

    The continuous development of nanotechnology has resulted in the actual possibility of the design and synthesis of nanostructured materials with pre-tailored functionabilities. Nanostructures capable of simultaneous heating and local thermal sensing are in strong demand as they would constitute a revolutionary solution to several challenging problems in bio-medicine, including the achievement of real time control during photothermal therapies. Several approaches have been demonstrated to achieve simultaneous heating and thermal sensing at the nanoscale. Some of them lack of sufficient thermal sensitivity and others require complicated synthesis procedures for heterostructure fabrication. In this study, we demonstrate how single core/shell dielectric nanoparticles with a highly Nd(3+) ion doped shell and an Yb(3+),Er(3+) codoped core are capable of simultaneous thermal sensing and heating under an 808 nm single beam excitation. The spatial separation between the heating shell and sensing core provides remarkable values of the heating efficiency and thermal sensitivity, enabling their application in single beam-controlled heating experiments in both aqueous and tissue environments. PMID:26786666

  3. Polymer Surface Engineering for Efficient Printing of Highly Conductive Metal Nanoparticle Inks.

    PubMed

    Agina, Elena V; Sizov, Alexey S; Yablokov, Mikhail Yu; Borshchev, Oleg V; Bessonov, Alexander A; Kirikova, Marina N; Bailey, Marc J A; Ponomarenko, Sergei A

    2015-06-10

    An approach to polymer surface modification using self-assembled layers (SALs) of functional alkoxysilanes has been developed in order to improve the printability of silver nanoparticle inks and enhance adhesion between the metal conducting layer and the flexible polymer substrate. The SALs have been fully characterized by AFM, XPS, and WCA, and the resulting printability, adhesion, and electrical conductivity of the screen-printed metal contacts have been estimated by cross-cut tape test and 4-point probe measurements. It was shown that (3-mercaptopropyl)trimethoxysilane SALs enable significant adhesion improvements for both aqueous- and organic-based silver inks, approaching nearly 100% for PEN and PDMS substrates while exhibiting relatively low sheet resistance up to 0.1 Ω/sq. It was demonstrated that SALs containing functional -SH or -NH2 end groups offer the opportunity to increase the affinity of the polymer substrates to silver inks and thus to achieve efficient patterning of highly conductive structures on flexible and stretchable substrates. PMID:25984650

  4. Engineering of air-stable Fe/C/Pd composite nanoparticles for environmental remediation applications

    NASA Astrophysics Data System (ADS)

    Haham, Hai; Grinblat, Judith; Sougrati, Moulay-Tahar; Stievano, Lorenzo; Margel, Shlomo

    2015-09-01

    The present manuscript presents a convenient method for the synthesis of iron/carbon (Fe/C) nanoparticles (NPs) coated with much smaller Pd NPs for the removal of halogenated organic pollutants. For this purpose, iron oxide/polyvinylpyrrolidone (IO/PVP) NPs were first prepared by the thermal decomposition of ferrocene mixed with PVP at 350 °C under an inert atmosphere. IO,Fe/C and Fe/C NPs coated with graphitic and amorphous carbon layers were then produced by annealing the IO/PVP NPs at 500 and 600 °C, respectively, under an inert atmosphere. The effect of the annealing temperature on the chemical composition, shape, crystallinity, surface area and magnetic properties of the IO/PVP, IO,Fe/C and Fe/C NPs has been elucidated. Air-stable Fe/C/Pd NPs were produced by mixing the precursor palladium acetate with the air-stable Fe/C NPs in ethanol. The obtained Fe/C/Pd NPs demonstrated significantly higher environmental activity than the Fe/C NPs on eosin Y, a model halogenated organic pollutant. The environmental activity of the Fe/C/Pd NPs also increased with their increasing Pd content.

  5. Physico-chemical characterization of engineered metal oxide nanoparticles: the critical role of microscopy

    NASA Astrophysics Data System (ADS)

    La Fontaine, A.; Coleman, V. A.; Jämting, A. K.; Lawn, M.; Herrmann, J.; Miles, J. R.

    2010-06-01

    Three different methods for extracting zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles from commercially available sunscreen were investigated to determine the most appropriate route for producing a sample suitable for measuring the primary particle size. Direct dilution of the formulation, centrifugal methods and chemical washing were trialed in combination with ultrasonic processing and surfactant addition to generate samples that are suitable for particle size analysis. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to monitor the extraction and re-dispersion process. Washing with hexane, methanol and water to remove the formulation, in combination with pulsed high-powered ultrasonication and the addition of a charge-stabilizing surfactant was found to be the most efficient way of producing de-agglomerated samples. DLS measurements gave average hydrodynamic particle diameters of 87 nm for ZnO and 76 nm for TiO2, compared to equivalent spherical particle diameters of 21 +/- 12 nm for ZnO (81 particles) and 19 +/- 14 nm for TiO2 (81 particles) obtained from TEM analysis.

  6. Self-monitored photothermal nanoparticles based on core-shell engineering

    NASA Astrophysics Data System (ADS)

    Ximendes, Erving C.; Rocha, Uéslen; Jacinto, Carlos; Kumar, Kagola Upendra; Bravo, David; López, Fernando J.; Rodríguez, Emma Martín; García-Solé, José; Jaque, Daniel

    2016-01-01

    The continuous development of nanotechnology has resulted in the actual possibility of the design and synthesis of nanostructured materials with pre-tailored functionabilities. Nanostructures capable of simultaneous heating and local thermal sensing are in strong demand as they would constitute a revolutionary solution to several challenging problems in bio-medicine, including the achievement of real time control during photothermal therapies. Several approaches have been demonstrated to achieve simultaneous heating and thermal sensing at the nanoscale. Some of them lack of sufficient thermal sensitivity and others require complicated synthesis procedures for heterostructure fabrication. In this study, we demonstrate how single core/shell dielectric nanoparticles with a highly Nd3+ ion doped shell and an Yb3+,Er3+ codoped core are capable of simultaneous thermal sensing and heating under an 808 nm single beam excitation. The spatial separation between the heating shell and sensing core provides remarkable values of the heating efficiency and thermal sensitivity, enabling their application in single beam-controlled heating experiments in both aqueous and tissue environments.

  7. Engineering the hot spots in squared arrays of gold nanoparticles on a silver film.

    PubMed

    Li, Anran; Srivastava, Sachin K; Abdulhalim, Ibrahim; Li, Shuzhou

    2016-08-25

    Density of nanoparticle (NP) arrays affects the hot spots distribution and strength in NP-metal film (NP-MF) geometry. In-depth understanding of the variation of electromagnetic (EM) field enhancement with NPs density is essential for wide applications of the NP-MF geometry such as surface-enhanced spectroscopies and enhanced efficiency of optoelectronic devices. Here, we show that the field distribution in the NP array on the metal film is greatly enhanced and confined at the NP-NP junctions for very small horizontal gap (g) between neighboring NPs, whereas the fields at the NP-MF junction are extremely small. When gradually increasing g, the field enhancement at the NP-NP junction decreases, along with the gradually enhanced fields at the NP-MF junction. We show that there is an optimal value of horizontal gap (∼75 nm for 80 nm Au NP array on Ag film with 532 nm normal incidence), indicating that the average field enhancement in NP-MF geometry can be optimized by adjusting the horizontal gap. More importantly, it is found that the EM field enhancement is greatly decreased when g fulfills the requirement to couple the 532 nm incident light into SPPs, because of the interference between the LSPR and the SPPs, which leads to a Fano dip at the incident wavelength of 532 nm. PMID:27515538

  8. Cellular Targets and Mechanisms in the Cytotoxic Action of Non-biodegradable Engineered Nanoparticles

    PubMed Central

    Fröhlich, Eleonore

    2013-01-01

    The use of nanoparticles (NPs) has improved the quality of many industrial, pharmaceutical, and medical products. Increased surface reactivity, a major reason for the positive effects of NPs, may, on the other hand, also cause adverse biological effects. Almost all non-biodegradable NPs cause cytotoxic effects but employ quite different modes of action. The relation of biodegradable or loaded NPs to cytotoxic mechanism is more difficult to identify because effects may by caused by the particles or degradation products thereof. This review introduces problems of NPs in conventional cytotoxicity testing (changes of particle parameters in biological fluids, cellular dose, cell line and assay selection). Generation of reactive oxygen and nitrogen species by NPs and of metal ions due to dissolution of the NPs is discussed as a cause for cytotoxicity. The effects of NPs on plasma membrane, mitochondria, lysosomes, nucleus, and intracellular proteins as cellular targets for cytotoxicity are summarized. The comparison of the numerous studies on the mechanism of cellular effects shows that, although some common targets have been identified, other effects are unique for particular NPs or groups of NPs. While titanium dioxide NPs appear to act mainly by generation of reactive oxygen and nitrogen species, biological effects of silver and iron oxide are caused by both reactive species and free metal ions. NPs lacking heavy metals, such as carbon nanotubes and polystyrene particles, interfere with cell metabolism mainly by binding to macromolecules. PMID:24160294

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

    PubMed Central

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

    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 programming (NLP) and chance-constrained programming (CCP), and handles uncertainties associated with both the nanomaterial production and workplace exposure control. The CCNLP method was examined through a single-walled carbon nanotube (SWNT) manufacturing process. The study results provide optimal production strategies and alternatives. It reveal that a high control measure guarantees that environmental health and safety (EHS) standards regulations are met, while a lower control level leads to increased risk of violating EHS regulations. The CCNLP optimization approach is a decision support tool for the optimization of the increasing MNMS manufacturing with workplace safety constraints under uncertainties. PMID:23531490

  10. Surface engineered magnetic nanoparticles for specific immunotargeting of cadherin expressing cells

    NASA Astrophysics Data System (ADS)

    Moros, Maria; Delhaes, Flavien; Puertas, Sara; Saez, Berta; de la Fuente, Jesús M.; Grazú, Valeria; Feracci, Helene

    2016-02-01

    In spite of historic advances in cancer biology and recent development of sophisticated chemotherapeutics, the outlook for patients with advanced cancer is still grim. In this sense nanoparticles (NPs), through their unique physical properties, enable the development of new approaches for cancer diagnosis and treatment. Thus far the most used active targeting scheme involves NPs functionalization with antibodies specific to molecules overexpressed on cancer cell’s surface. Therefore, such active targeting relies on differences in NPs uptake kinetics rates between tumor and healthy cells. Many cancers of epithelial origin are associated with the inappropriate expression of non-epithelial cadherins (e.g. N-, P-, -11) with concomitant loss of E-cadherin. Such phenomenon named cadherin switching favors tumor development and metastasis via interactions of tumor cells with stromal components. That is why we optimized the oriented functionalization of fluorescently labelled magnetic NPs with a novel antibody specific for the extracellular domain of cadherin-11. The obtained Ab-NPs exhibited high specificity when incubated with two cell lines used as models of tumor and healthy cells. Thus, cadherin switching offers a great opportunity for the development of active targeting strategies aimed to improve the early detection and treatment of cancer.

  11. Intraparticle Molecular Orbital Engineering of Semiconducting Polymer Nanoparticles as Amplified Theranostics for in Vivo Photoacoustic Imaging and Photothermal Therapy.

    PubMed

    Lyu, Yan; Fang, Yuan; Miao, Qingqing; Zhen, Xu; Ding, Dan; Pu, Kanyi

    2016-04-26

    Optical theranostic nanoagents that seamlessly and synergistically integrate light-generated signals with photothermal or photodynamic therapy can provide opportunities for cost-effective precision medicine, while the potential for clinical translation requires them to have good biocompatibility and high imaging/therapy performance. We herein report an intraparticle molecular orbital engineering approach to simultaneously enhance photoacoustic brightness and photothermal therapy efficacy of semiconducting polymer nanoparticles (SPNs) for in vivo imaging and treatment of cancer. The theranostic SPNs have a binary optical component nanostructure, wherein a near-infrared absorbing semiconducting polymer and an ultrasmall carbon dot (fullerene) interact with each other to induce photoinduced electron transfer upon light irradiation. Such an intraparticle optoelectronic interaction augments heat generation and consequently enhances the photoacoustic signal and maximum photothermal temperature of SPNs by 2.6- and 1.3-fold, respectively. With the use of the amplified SPN as the theranostic nanoagent, it permits enhanced photoacoustic imaging and photothermal ablation of tumor in living mice. Our study thus not only introduces a category of purely organic optical theranostics but also highlights a molecular guideline to amplify the effectiveness of light-intensive imaging and therapeutic nanosystems. PMID:26959505

  12. Interactions of metal-based engineered nanoparticles with aquatic higher plants: A review of the state of current knowledge.

    PubMed

    Thwala, Melusi; Klaine, Stephen J; Musee, Ndeke

    2016-07-01

    The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data. Environ Toxicol Chem 2016;35:1677-1694. © 2016 SETAC. PMID:26757140

  13. Engineering Chimeric Receptors To Investigate the Size- and Rigidity-Dependent Interaction of PEGylated Nanoparticles with Cells.

    PubMed

    Huang, Wei-Chiao; Burnouf, Pierre-Alain; Su, Yu-Cheng; Chen, Bing-Mae; Chuang, Kuo-Hsiang; Lee, Chia-Wei; Wei, Pei-Kuen; Cheng, Tian-Lu; Roffler, Steve R

    2016-01-26

    Attachment of ligands to the surface of nanoparticles (NPs) is an attractive approach to target specific cells and increase intracellular delivery of nanocargos. To expedite investigation of targeted NPs, we engineered human cancer cells to express chimeric receptors that bind polyethylene glycol (PEG) and internalize stealth NPs in a fashion similar to ligand-targeted liposomes against epidermal growth factor receptor 1 or 2 (HER1 or HER2), which are validated targets for cancer therapy. Measurement of the rate of endocytosis and lysosomal accumulation of small (80-94 nm) or large (180-220 nm) flexible liposomes or more rigid lipid-coated mesoporous silica particles in human HT29 colon cancer and SKBR3 breast cancer cells that express chimeric receptors revealed that larger and more rigid NPs were internalized more slowly than smaller and more flexible NPs. An exception is when both the small and large liposomes underwent endocytosis via HER2. HER1 mediated faster and greater uptake of NPs into cells but retained NPs less well as compared to HER2. Lysosomal accumulation of NPs internalized via HER1 was unaffected by NP rigidity but was inversely related to NP size, whereas large rigid NPs internalized by HER2 displayed increased lysosomal accumulation. Our results provide insight into the effects of NP properties on receptor-mediated endocytosis and suggest that anti-PEG chimeric receptors may help accelerate investigation of targeted stealth NPs. PMID:26741147

  14. Research unit INTERNANO: Mobility, aging and functioning of engineered inorganic nanoparticles at the aquatic-terrestrial interface

    NASA Astrophysics Data System (ADS)

    Schaumann, Gabriele Ellen; Metreveli, George; Baumann, Thomas; Klitzke, Sondra; Lang, Friederike; Manz, Werner; Nießner, Reinhard; Schulz, Ralf; Vogel, Hans-Jörg

    2013-04-01

    Engineered inorganic nanoparticles (EINP) are expected to pass the wastewater-river-topsoil-groundwater pathway. Despite their increasing release, the processes governing the EINP aging and the changes in functionality in the environment are up to now largely unknown. The objective of the interdisciplinary research unit INTERNANO funded by the DFG is to identify the processes relevant for the fate of EINP and EINP-associated pollutants in the interfacial zone between aquatic and terrestrial ecosystems. The research unit consists of six subprojects and combines knowledge from aquatic and terrestrial sciences as well as from microbiology, ecotoxicology, physicochemistry, soil chemistry and soil physics. For the identification of key processes we will consider compartment specific flow conditions, physicochemistry and biological activity. Situations representative for a floodplain system are simulated using micromodels (μm scale) as well as incubation, soil column and joint laboratory stream microcosm experiments. These results will be transferred to a joint aquatic-terrestrial model system on EINP aging, transport and functioning across the aquatic-terrestrial transition zone. EINP isolation and characterization will be carried out via a combination of chromatographic, light scattering and microscopic methods including dynamic light scattering, elemental analysis, hydrodynamic radius chromatography, field flow fractionation as well as atomic force microscopy, Raman microscopy and electron microscopy. INTERNANO generates fundamental aquatic-terrestrial process knowledge, which will help to evaluate the environmental significance of the EINP at aquatic-terrestrial interfaces. Thus, INTERNANO provides a scientific basis to assess and predict the environmental impact of EINP release into the environment.

  15. Fate of engineered cerium oxide nanoparticles in an aquatic environment and their toxicity toward 14 ciliated protist species.

    PubMed

    Zhang, Wei; Pu, Zhichao; Du, Songyan; Chen, Yongsheng; Jiang, Lin

    2016-05-01

    The potential environmental impacts of engineered cerium oxide nanoparticles (CeO2 NPs) on aquatic organisms have remained largely unknown. Therefore, the laboratory study featured herein was performed to determine the fate of CeO2 NPs in an aquatic environment and their toxicity towards 14 different ciliated protist species at a specified population level. An investigation of 48 h aggregation kinetics in the Dryl's solution showed the CeO2 NPs to be relatively stable. The pH values in three test medium were too far away from PZC, which explained the stability of CeO2 NPs. CeO2 NPs generally elicited more toxicity with increasing NP concentration, following certain dose-response relationships. Nano-CeO2 resulted in greater toxicity in a particle state than when added as bulk material. LC50 values showed a negative correlation with the surface-to-volume ratio for these protists, suggesting that surface adsorption of CeO2 NPs might contribute to the observed toxicity. Additionally, acute toxic responses of 14 ciliated protist species to CeO2 NPs were not significantly phylogenetically conserved. The results of these observations provide a better insight into the potential risks of CeO2 NPs in an aquatic environment. PMID:26986089

  16. Airborne sensor integration for quick reaction programs

    NASA Astrophysics Data System (ADS)

    Gosian, Gregory; Mason, Kenneth; Servoss, Thomas; Brower, Bernard; Pellechia, Matthew

    2010-04-01

    In this paper we present an approach to integrate sensors to meet the demanding requirements of Quick Reaction Capability (QRC) airborne programs. Traditional airborne sensors are generally highly integrated and incorporate custom sensor technologies and interfaces. Custom solutions and new technologies often require significant engineering to achieve a high technology readiness level (TRL) and to meet the overall mission objective. Our approach differs from traditional approaches in that we strive to achieve an integrated solution through regular review, assessment, and identification of relevant industry "best athlete" technologies. Attention is focused on solution providers that adhere to standard interfaces and formats, incorporate non-proprietary techniques, are deemed highly-reliable/repeatable, and enable assembly production. Processes and engineering tools/methods have traditionally been applied to dozens of longer-acquisition space-based ISR programs over 50 years. We have recently leveraged these techniques to solve airborne Intelligence, Surveillance and Reconnaissance (ISR) mission challenges. This presentation describes and illustrates key aspects and examples of these techniques, solving real-world airborne mission needs.

  17. Toolsets for Airborne Data

    Atmospheric Science Data Center

    2015-04-02

    article title:  Toolsets for Airborne Data     View larger image The ... limit of detection values. Prior to accessing the TAD Web Application ( https://tad.larc.nasa.gov ) for the first time, users must ...

  18. Surface engineering of gold nanoparticles for in vitro siRNA delivery

    NASA Astrophysics Data System (ADS)

    Zhao, Enyu; Zhao, Zhixia; Wang, Jiancheng; Yang, Chunhui; Chen, Chengjun; Gao, Lingyan; Feng, Qiang; Hou, Wenjie; Gao, Mingyuan; Zhang, Qiang

    2012-07-01

    Cellular uptake, endosomal/lysosomal escape, and the effective dissociation from the carrier are a series of hurdles for specific genes to be delivered both in vitro and in vivo. To construct siRNA delivery systems, poly(allylamine hydrochloride) (PAH) and siRNA were alternately assembled on the surface of 11.8 +/- 0.9 nm Au nanoparticles (GNP), stabilized by denatured bovine serum albumin, by the ionic layer-by-layer (LbL) self-assembly method. By manipulating the outmost PAH layer, GNP-PAH vectors with different surface electric potentials were prepared. Then, the surface potential-dependent cytotoxicity of the resultant GNP-PAH particles was evaluated via sulforhodamine B (SRB) assay, while the surface potential-dependent cellular uptake efficiency was quantitatively analyzed by using the flow cytometry method based on carboxyfluorescein (FAM)-labeled siRNA. It was revealed that the GNP-PAH particles with surface potential of +25 mV exhibited the optimal cellular uptake efficiency and cytotoxicity for human breast cancer MCF-7 cells. Following these results, two more positively charged polyelectrolytes with different protonating abilities in comparison with PAH, i.e., polyethylenimine (PEI), and poly(diallyl dimethyl ammonium chloride) (PDDA), were chosen to fabricate similarly structured vectors. Confocal fluorescence microscopy studies indicated that siRNA delivered by GNP-PAH and GNP-PEI systems was better released than that delivered by the GNP-PDDA system. Further flow cytometric assays based on immunofluorescence staining of the epidermal growth factor receptor (EGFR) revealed that EGFR siRNA delivered by GNP-PAH and GNP-PEI exhibited similar down-regulation effects on EGFR expression in MCF-7 cells. The following dual fluorescence flow cytometry assays by co-staining phosphatidylserine and DNA suggested the EGFR siRNA delivered by GNP-PAH exhibited an improved silencing effect in comparison with that delivered by the commercial transfection reagent

  19. Precise engineering of dapivirine-loaded nanoparticles for the development of anti-HIV vaginal microbicides.

    PubMed

    das Neves, José; Sarmento, Bruno

    2015-05-01

    Polymeric nanoparticles (NPs) have the potential to provide effective and safe delivery of antiretroviral drugs in the context of prophylactic anti-HIV vaginal microbicides. Dapivirine-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) NPs were produced by an emulsion-solvent evaporation method, optimized for colloidal properties using a 3-factor, 3-level Box-Behnken experimental design, and characterized for drug loading, production yield, morphology, thermal behavior, drug release, in vitro cellular uptake, cytotoxicity and pro-inflammatory potential. Also, drug permeability/membrane retention in well-established HEC-1-A and CaSki cell monolayer models as mediated by NPs was assessed in the absence or presence of mucin. Box-Behnken design allowed optimizing monodisperse 170nm drug-loaded NPs. Drug release experiments showed an initial burst effect up to 4h, followed by sustained 24h release at pH 4.2 and 7.4. NPs were readily taken up by different genital and macrophage cell lines as assessed by fluorescence microscopy. Drug-loaded NPs presented lower or at least similar cytotoxicity as compared to the free drug, with up to around one-log increase in half-maximal cytotoxic concentration values. In all cases, no relevant changes in cell pro-inflammatory cytokine/chemokine production were observed. Dapivirine transport across cell monolayers was significantly decreased when mucin was present at the donor side with either NPs or the free drug, thus evidencing the influence of this natural glycoprotein in membrane permeability. Moreover, drug retention in cell monolayers was significantly higher for NPs in comparison with the free drug. Overall, obtained dapivirine-loaded PLGA NPs possess interesting technological and biological features that may contribute to their use as novel safe and effective vaginal microbicides. PMID:25700657

  20. The airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven; Schall, Harold; Shattuck, Paul

    2007-05-01

    The Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the current program status.

  1. Quantitatively probing propensity for structural transitions in engineered virus nanoparticles by single-molecule mechanical analysis

    NASA Astrophysics Data System (ADS)

    Castellanos, Milagros; Carrillo, Pablo J. P.; Mateu, Mauricio G.

    2015-03-01

    Viruses are increasingly being studied from the perspective of fundamental physics at the nanoscale as biologically evolved nanodevices with many technological applications. In viral particles of the minute virus of mice (MVM), folded segments of the single-stranded DNA genome are bound to the capsid inner wall and act as molecular buttresses that increase locally the mechanical stiffness of the particle. We have explored whether a quantitative linkage exists in MVM particles between their DNA-mediated stiffening and impairment of a heat-induced, virus-inactivating structural change. A series of structurally modified virus particles with disrupted capsid-DNA interactions and/or distorted capsid cavities close to the DNA-binding sites were engineered and characterized, both in classic kinetics assays and by single-molecule mechanical analysis using atomic force microscopy. The rate constant of the virus inactivation reaction was found to decrease exponentially with the increase in elastic constant (stiffness) of the regions closer to DNA-binding sites. The application of transition state theory suggests that the height of the free energy barrier of the virus-inactivating structural transition increases linearly with local mechanical stiffness. From a virological perspective, the results indicate that infectious MVM particles may have acquired the biological advantage of increased survival under thermal stress by evolving architectural elements that rigidify the particle and impair non-productive structural changes. From a nanotechnological perspective, this study provides proof of principle that determination of mechanical stiffness and its manipulation by protein engineering may be applied for quantitatively probing and tuning the conformational dynamics of virus-based and other protein-based nanoassemblies.Viruses are increasingly being studied from the perspective of fundamental physics at the nanoscale as biologically evolved nanodevices with many technological

  2. Precise engineering of siRNA delivery vehicles to tumors using polyion complexes and gold nanoparticles.

    PubMed

    Kim, Hyun Jin; Takemoto, Hiroyasu; Yi, Yu; Zheng, Meng; Maeda, Yoshinori; Chaya, Hiroyuki; Hayashi, Kotaro; Mi, Peng; Pittella, Frederico; Christie, R James; Toh, Kazuko; Matsumoto, Yu; Nishiyama, Nobuhiro; Miyata, Kanjiro; Kataoka, Kazunori

    2014-09-23

    For systemic delivery of siRNA to solid tumors, a size-regulated and reversibly stabilized nanoarchitecture was constructed by using a 20 kDa siRNA-loaded unimer polyion complex (uPIC) and 20 nm gold nanoparticle (AuNP). The uPIC was selectively prepared by charge-matched polyionic complexation of a poly(ethylene glycol)-b-poly(L-lysine) (PEG-PLL) copolymer bearing ∼40 positive charges (and thiol group at the ω-end) with a single siRNA bearing 40 negative charges. The thiol group at the ω-end of PEG-PLL further enabled successful conjugation of the uPICs onto the single AuNP through coordinate bonding, generating a nanoarchitecture (uPIC-AuNP) with a size of 38 nm and a narrow size distribution. In contrast, mixing thiolated PEG-PLLs and AuNPs produced a large aggregate in the absence of siRNA, suggesting the essential role of the preformed uPIC in the formation of nanoarchitecture. The smart uPIC-AuNPs were stable in serum-containing media and more resistant against heparin-induced counter polyanion exchange, compared to uPICs alone. On the other hand, the treatment of uPIC-AuNPs with an intracellular concentration of glutathione substantially compromised their stability and triggered the release of siRNA, demonstrating the reversible stability of these nanoarchitectures relative to thiol exchange and negatively charged AuNP surface. The uPIC-AuNPs efficiently delivered siRNA into cultured cancer cells, facilitating significant sequence-specific gene silencing without cytotoxicity. Systemically administered uPIC-AuNPs showed appreciably longer blood circulation time compared to controls, i.e., bare AuNPs and uPICs, indicating that the conjugation of uPICs onto AuNP was crucial for enhancing blood circulation time. Finally, the uPIC-AuNPs efficiently accumulated in a subcutaneously inoculated luciferase-expressing cervical cancer (HeLa-Luc) model and achieved significant luciferase gene silencing in the tumor tissue. These results demonstrate the strong

  3. Adipose Tissue Engineering in Three-Dimensional Levitation Tissue Culture System Based on Magnetic Nanoparticles

    PubMed Central

    Daquinag, Alexes C.; Souza, Glauco R.

    2013-01-01

    White adipose tissue (WAT) is becoming widely used in regenerative medicine/cell therapy applications, and its physiological and pathological importance is increasingly appreciated. WAT is a complex organ composed of differentiated adipocytes, stromal mesenchymal progenitors known as adipose stromal cells (ASC), as well as endothelial vascular cells and infiltrating leukocytes. Two-dimensional (2D) culture that has been typically used for studying adipose cells does not adequately recapitulate WAT complexity. Improved methods for reconstruction of functional WAT ex vivo are instrumental for understanding of physiological interactions between the composing cell populations. Here, we used a three-dimensional (3D) levitation tissue culture system based on magnetic nanoparticle assembly to model WAT development and growth in organoids termed adipospheres. We show that 3T3-L1 preadipocytes remain viable in spheroids for a long period of time, while in 2D culture, they lose adherence and die after reaching confluence. Upon adipogenesis induction in 3T3-L1 adipospheres, cells efficiently formed large lipid droplets typical of white adipocytes in vivo, while only smaller lipid droplet formation is achievable in 2D. Adiposphere-based coculture of 3T3-L1 preadipocytes with murine endothelial bEND.3 cells led to a vascular-like network assembly concomitantly with lipogenesis in perivascular cells. Adipocyte-depleted stromal vascular fraction (SVF) of mouse WAT cultured in 3D underwent assembly into organoids with vascular-like structures containing luminal endothelial and perivascular stromal cell layers. Adipospheres made from primary WAT cells displayed robust proliferation and complex hierarchical organization reflected by a matricellular gradient incorporating ASC, endothelial cells, and leukocytes, while ASC quickly outgrew other cell types in adherent culture. Upon adipogenesis induction, adipospheres derived from the SVF displayed more efficient lipid droplet

  4. Compact, Engineered, 2-Micron Coherent Doppler Wind Lidar Prototype for Field and Airborne Validation: Doppler Aerosol WiNd Lidar (DAWN). Interim Review #1 (6 months)

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J.; Singh, Upendra N.; Koch, Grady J.; Yu, Jirong; Amzajerdian, Farzin; Trieu, Bo C.; Petros, Mulugeta

    2006-01-01

    A new project, selected in 2005 by NASA's Science Mission Directorate (SMD), under the Instrument Incubator Program (IIP), will be described. The 3-year effort is intended to design, fabricate, and demonstrate a packaged, rugged, compact, space-qualifiable coherent Doppler wind lidar (DWL) transceiver capable of future validation in an aircraft and/or Unmanned Aerial Vehicle (UAV). The state-of-the-art 2-micron coherent DWL breadboard at NASA/LaRC will be engineered and compactly packaged consistent with future aircraft flights. The packaged transceiver will be integrated into a coherent DWL system test bed at LaRC. Atmospheric wind measurements will be made to validate the packaged technology. This will greatly advance the coherent part of the hybrid DWL solution to the need for global tropospheric wind measurements.

  5. Modeling In Vivo Interactions of Engineered Nanoparticles in the Pulmonary Alveolar Lining Fluid

    PubMed Central

    Mukherjee, Dwaipayan; Porter, Alexandra; Ryan, Mary; Schwander, Stephan; Chung, Kian Fan; Tetley, Teresa; Zhang, Junfeng; Georgopoulos, Panos

    2015-01-01

    Increasing use of engineered nanomaterials (ENMs) in consumer products may result in widespread human inhalation exposures. Due to their high surface area per unit mass, inhaled ENMs interact with multiple components of the pulmonary system, and these interactions affect their ultimate fate in the body. Modeling of ENM transport and clearance in vivo has traditionally treated tissues as well-mixed compartments, without consideration of nanoscale interaction and transformation mechanisms. ENM agglomeration, dissolution and transport, along with adsorption of biomolecules, such as surfactant lipids and proteins, cause irreversible changes to ENM morphology and surface properties. The model presented in this article quantifies ENM transformation and transport in the alveolar air to liquid interface and estimates eventual alveolar cell dosimetry. This formulation brings together established concepts from colloidal and surface science, physics, and biochemistry to provide a stochastic framework capable of capturing essential in vivo processes in the pulmonary alveolar lining layer. The model has been implemented for in vitro solutions with parameters estimated from relevant published in vitro measurements and has been extended here to in vivo systems simulating human inhalation exposures. Applications are presented for four different ENMs, and relevant kinetic rates are estimated, demonstrating an approach for improving human in vivo pulmonary dosimetry. PMID:26240755

  6. Airborne Research Experience for Educators

    NASA Astrophysics Data System (ADS)

    Costa, V. B.; Albertson, R.; Smith, S.; Stockman, S. A.

    2009-12-01

    The Airborne Research Experience for Educators (AREE) Program, conducted by the NASA Dryden Flight Research Center Office of Education in partnership with the AERO Institute, NASA Teaching From Space Program, and California State University Fullerton, is a complete end-to-end residential research experience in airborne remote sensing and atmospheric science. The 2009 program engaged ten secondary educators who specialize in science, technology, engineering or mathematics in a 6-week Student Airborne Research Program (SARP) offered through NSERC. Educators participated in collection of in-flight remote sensor data during flights aboard the NASA DC-8 as well as in-situ research on atmospheric chemistry (bovine emissions of methane); algal blooms (remote sensing to determine location and degree of blooms for further in-situ analysis); and crop classification (exploration of how drought conditions in Central California have impacted almond and cotton crops). AREE represents a unique model of the STEM teacher-as-researcher professional development experience because it asks educators to participate in a research experience and then translate their experiences into classroom practice through the design, implementation, and evaluation of instructional materials that emphasize the scientific research process, inquiry-based investigations, and manipulation of real data. Each AREE Master Educator drafted a Curriculum Brief, Teachers Guide, and accompanying resources for a topic in their teaching assignment Currently, most professional development programs offer either a research experience OR a curriculum development experience. The dual nature of the AREE model engaged educators in both experiences. Educators’ content and pedagogical knowledge of STEM was increased through the review of pertinent research articles during the first week, attendance at lectures and workshops during the second week, and participation in the airborne and in-situ research studies, data

  7. Research unit INTERNANO: Mobility, aging and functioning of engineered inorganic nanoparticles at the aquatic-terrestrial interface

    NASA Astrophysics Data System (ADS)

    Schaumann, G. E.; Baumann, T.; Duester, L.; Klitzke, S.; Lang, F.; Manz, W.; Nießner, R.; Schulz, R.; Vogel, H.-J.

    2012-04-01

    Engineered inorganic nanoparticles (EINP) are expected to pass the wastewater-river-topsoil-groundwater pathway. Despite their increasing release, the processes governing the EINP aging and the changes in functionality in the environment are up to now largely unknown. The objective of the interdisciplinary research unit INTERNANO funded by the German Research Foundation (DFG) is to identify the processes relevant for the fate of EINP and EINP-associated pollutants in the interfacial zone between aquatic and terrestrial ecosystems. The research unit consists of six subprojects and combines knowledge from aquatic and terrestrial sciences as well as from microbiology, ecotoxicology, physicochemistry, soil chemistry and soil physics. For the identification of key processes we will consider compartment specific flow conditions, physicochemistry and biological activity. Situations representative for a floodplain system are simulated using micromodels (μm scale) as well as incubation, soil column and joint laboratory stream microcosm experiments. These results will be transferred to a joint aquatic-terrestrial model system on EINP aging, transport and functioning across the aquatic-terrestrial transition zone. EINP isolation and characterization will be carried out via a combination of chromatographic, light scattering and microscopic methods including dynamic light scattering, elemental analysis, hydrodynamic radius chromatography, field flow fractionation as well as atomic force microscopy, Raman microscopy, dynamic light scattering methods and electron microscopy. INTERNANO generates fundamental aquatic-terrestrial process knowledge, which will help to evaluate the environmental significance of the EINP at aquatic-terrestrial interfaces. Therefore, INTERNANO serves as a qualitative basis to predict the environmental impact of EINP contamination.

  8. Response to shock load of engineered nanoparticles in an activated sludge treatment system: Insight into microbial community succession.

    PubMed

    Zhang, Jing; Dong, Qian; Liu, Yanchen; Zhou, Xiaohong; Shi, Hanchang

    2016-02-01

    The environmental impacts of the use of engineered nanoparticles (NPs) remain unclear and have attracted increasing concern worldwide. Considering that NPs eventually end up in wastewater treatment systems, the potential impact of ZnO and TiO2 NPs on the activated sludge was investigated using laboratory-scale sequencing batch reactors (SBRs). Short-term (24 h) exposure to 1, 10 and 100 mg/L shock loads of NPs reduced the oxygen uptake rate of the activated sludge by 3.55%-12.51% compared with the controls. In our experiment, the toxicities of TiO2 NPs were higher than those of ZnO NPs as reflected in the inhibition of oxygen utilization in the activated sludge. However, both the short-term (24 h) and long-term (21 days) exposure to ZnO and TiO2 NPs did not adversely affect the pollutant removal of the SBRs. Furthermore, the polymerase chain reaction-denaturing gel gradient electrophoresis revealed that the microbial community did not significantly vary after the short-term exposure (24 h) to 1, 10 and 100 mg/L shock loads of NPs; however, the cluster analysis in our experiment revealed that the slight difference caused by the NPs largely depended on exposure time rather than on NP type and NP concentration. The long-term exposure (13 days) to 10 mg/L shock load of ZnO or TiO2 NPs caused no substantial microbial community shifts in the activated sludge. The microbial diversity also showed no significant change when exposed to NPs as revealed by the Shannon-Wiener index. PMID:26539708

  9. Gene Expression Profiling of Immune-Competent Human Cells Exposed to Engineered Zinc Oxide or Titanium Dioxide Nanoparticles

    PubMed Central

    Tuomela, Soile; Autio, Reija; Buerki-Thurnherr, Tina; Arslan, Osman; Kunzmann, Andrea; Andersson-Willman, Britta; Wick, Peter; Mathur, Sanjay; Scheynius, Annika; Krug, Harald F.; Fadeel, Bengt; Lahesmaa, Riitta

    2013-01-01

    A comprehensive in vitro assessment of two commercial metal oxide nanoparticles, TiO2 and ZnO, was performed using human monocyte-derived macrophages (HMDM), monocyte-derived dendritic cells (MDDC), and Jurkat T cell leukemia-derived cell line. TiO2 nanoparticles were found to be non-toxic whereas ZnO nanoparticles caused dose-dependent cell death. Subsequently, global gene expression profiling was performed to identify transcriptional response underlying the cytotoxicity caused by ZnO nanoparticles. Analysis was done with doses 1 µg/ml and 10 µg/ml after 6 and 24 h of exposure. Interestingly, 2703 genes were significantly differentially expressed in HMDM upon exposure to 10 µg/ml ZnO nanoparticles, while in MDDCs only 12 genes were affected. In Jurkat cells, 980 genes were differentially expressed. It is noteworthy that only the gene expression of metallothioneins was upregulated in all the three cell types and a notable proportion of the genes were regulated in a cell type-specific manner. Gene ontology analysis revealed that the top biological processes disturbed in HMDM and Jurkat cells were regulating cell death and growth. In addition, genes controlling immune system development were affected. Using a panel of modified ZnO nanoparticles, we obtained an additional support that the cellular response to ZnO nanoparticles is largely dependent on particle dissolution and show that the ligand used to modify ZnO nanoparticles modulates Zn2+ leaching. Overall, the study provides an extensive resource of transcriptional markers for mediating ZnO nanoparticle-induced toxicity for further mechanistic studies, and demonstrates the value of assessing nanoparticle responses through a combined transcriptomics and bioinformatics approach. PMID:23894303

  10. Area 2. Use Of Engineered Nanoparticle-Stabilized CO2 Foams To Improve Volumetric Sweep Of CO2 EOR Processes

    SciTech Connect

    DiCarlo, David; Huh, Chun; Johnston, Keith P.

    2015-01-31

    The goal of this project was to develop a new CO2 injection enhanced oil recovery (CO2-EOR) process using engineered nanoparticles with optimized surface coatings that has better volumetric sweep efficiency and a wider application range than conventional CO2-EOR processes. The main objectives of this project were to (1) identify the characteristics of the optimal nanoparticles that generate extremely stable CO2 foams in situ in reservoir regions without oil; (2) develop a novel method of mobility control using “self-guiding” foams with smart nanoparticles; and (3) extend the applicability of the new method to reservoirs having a wide range of salinity, temperatures, and heterogeneity. Concurrent with our experimental effort to understand the foam generation and transport processes and foam-induced mobility reduction, we also developed mathematical models to explain the underlying processes and mechanisms that govern the fate of nanoparticle-stabilized CO2 foams in porous media and applied these models to (1) simulate the results of foam generation and transport experiments conducted in beadpack and sandstone core systems, (2) analyze CO2 injection data received from a field operator, and (3) aid with the design of a foam injection pilot test. Our simulator is applicable to near-injection well field-scale foam injection problems and accounts for the effects due to layered heterogeneity in permeability field, foam stabilizing agents effects, oil presence, and shear-thinning on the generation and transport of nanoparticle-stabilized C/W foams. This report presents the details of our experimental and numerical modeling work and outlines the highlights of our findings.

  11. The Airborne Laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-09-01

    The US Air Force Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the risk reduction approach being utilized to ensure program success.

  12. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  13. Heteroaggregation of cerium oxide nanoparticles and nanoparticles of pyrolyzed biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heteroaggregation with indigenous particles is an important process controlling the mobility of engineered nanomaterials in the environment. We studied heteroaggregation of cerium oxide nanoparticles (n-CeO2), which are widely used commercially, with nanoparticles of pyrogenic carbonaceous material ...

  14. NASA Airborne Lidar July 1991

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar July 1991 Data from the 1991 NASA Langley Airborne Lidar flights following the eruption of Pinatubo in July ... and Osborn [1992a, 1992b]. Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  15. NASA Airborne Lidar May 1992

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar May 1992 An airborne Nd:YAG (532 nm) lidar was operated by the NASA Langley Research Center about a year following the June 1991 eruption of ... Osborn [1992a, 1992b].  Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  16. Airborne antenna pattern calculations

    NASA Technical Reports Server (NTRS)

    Knerr, T. J.; Schaffner, P. R.; Mielke, R. R.; Gilreath, M. C.

    1980-01-01

    A procedure for numerically calculating radiation patterns of fuselage-mounted airborne antennas using the Volumetric Pattern Analysis Program is presented. Special attention is given to aircraft modeling. An actual case study involving a large commercial aircraft is included to illustrate the analysis procedure.

  17. Recognizing Airborne Hazards.

    ERIC Educational Resources Information Center

    Schneider, Christian M.

    1990-01-01

    The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)

  18. Airborne Fraunhofer Line Discriminator

    NASA Technical Reports Server (NTRS)

    Gabriel, F. C.; Markle, D. A.

    1969-01-01

    Airborne Fraunhofer Line Discriminator enables prospecting for fluorescent materials, hydrography with fluorescent dyes, and plant studies based on fluorescence of chlorophyll. Optical unit design is the coincidence of Fraunhofer lines in the solar spectrum occurring at the characteristic wavelengths of some fluorescent materials.

  19. Airborne Remote Sensing

    NASA Technical Reports Server (NTRS)

    1992-01-01

    NASA imaging technology has provided the basis for a commercial agricultural reconnaissance service. AG-RECON furnishes information from airborne sensors, aerial photographs and satellite and ground databases to farmers, foresters, geologists, etc. This service produces color "maps" of Earth conditions, which enable clients to detect crop color changes or temperature changes that may indicate fire damage or pest stress problems.

  20. Effects of Natural Organic Matter on Stability, Transport and Deposition of Engineered Nano-particles in Porous Media

    EPA Science Inventory

    The interaction of nano-particles and organic substances, like natural organic matter, could have significant influence on the fate, transport and bioavailability of toxic substances. Natural organic matter (NOM) is a mixture of chemically complex polyelectrolytes with varying m...

  1. Strain distribution of confined Ge/GeO2 core/shell nanoparticles engineered by growth environments

    NASA Astrophysics Data System (ADS)

    Wei, Wenyan; Yuan, Cailei; Luo, Xingfang; Yu, Ting; Wang, Gongping

    2016-02-01

    The strain distributions of Ge/GeO2 core/shell nanoparticles confined in different host matrix grown by surface oxidation are investigated. The simulated results by finite element method demonstrated that the strains of the Ge core and the GeO2 shell strongly depend on the growth environments of the nanoparticles. Moreover, it can be found that there is a transformation of the strain on Ge core from tensile to compressive strain during the growth of Ge/GeO2 core/shell nanoparticles. And, the transformation of the strain is closely related with the Young's modulus of surrounding materials of Ge/GeO2 core/shell nanoparticles.

  2. International Symposium on Airborne Geophysics

    NASA Astrophysics Data System (ADS)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  3. Interfacial engineering of nanoparticle systems: Assesment of electron transfer in inter and intrananoparticle photosystems as well as sensing applications

    NASA Astrophysics Data System (ADS)

    Phebus, Bruce Drury

    Electron transfer within nanochemical systems plays a key role in their uses. This body of work looks to better understand the conditions required for electron transport within these nanochemical systems and under what circumstances does it play a role in their use. Assessing electron transfer from aqueous graphene nanoparticles to aqueous ions through observation by quenching photoluminescence pointed to interesting requirements for transfer. Sensitivity was observed down to 1.6x10 -6 M for the most strongly quenching ions. More interesting though was a marked dependence on chemical hardness of the ions, with specific chemical hardness required to quench each graphene quantum dot species. Graphene quantum dots sourced from carbon fiber were observed to quench best with ions near that of 8.50 eV chemical hardness, like that of nickelous ions. Nitrogen doped graphene quantum dots were observed to quench best with ions near 7.70 eV in chemical hardness, like that of mercuric ions. The shift to a lower hardness is also noted in a shift toward lower excitation energy of the nanoparticles. For some ions concentration dependence was observed, with ions increasing PL emission initially then subsequently acting as quenchers. This behavior points to multiple quenching sites on the nanoparticles with different complexation values, some leading to stabilization of the PL emission when complexed. EDTA, ethylenediaminetetraacetic acid, was used as a complexing agent to assess possible recovery of emissions. EDTA was observed to complex ions and recovers some PL emission from some ions, with recovery dependent not only on quenching efficiency of the ion but the complexation constant. The most intriguing behavior was observed for aluminum ions which were observed to further quench with additions of EDTA after a critical point emission started to recover. We ascribe this behavior to multiple complexation sites on the nanoparticles with varied concentration and distinct roles in

  4. The Role of Oxidative Stress in Ambient Particulate Matter-induced Lung Diseases and Its Implications in the Toxicity of Engineered Nanoparticles

    PubMed Central

    Li, Ning; Xia, Tian; Nel, Andre E.

    2008-01-01

    Ambient particulate matter (PM) is an environmental factor that has been associated with increased respiratory morbidity and mortality. The major effect of ambient PM on the pulmonary system is the exacerbation of inflammation, especially in susceptible people. One of the mechanisms by which ambient PM exerts its proinflammatory effects is the generation of oxidative stress by its chemical compounds and metals. Cellular responses to PM-induced oxidative stress include activation of antioxidant defense, inflammation, and toxicity. The pro-inflammatory effect of PM in the lung is characterized by increased cytokine/chemokine production and adhesion molecule expression. Moreover, there is evidence that ambient PM can act as an adjuvant for allergic sensitization, which raises the possibility that long-term PM exposure may lead to increased prevalence of asthma. In addition to ambient PM, rapid expansion of nanotechnology has introduced the potential that engineered NP may also become airborne and may contribute to pulmonary diseases by novel mechanisms that could include oxidant injury. Currently, little is known about the potential adverse health effect of these particles. In this communication, the mechanisms by which particulate pollutants, including ambient PM and engineered NP, exert their adverse effects through the generation of oxidative stress and the impacts of oxidant injury in the respiratory tract will be reviewed. The importance of cellular antioxidant and detoxification pathways in protecting against particle-induced lung damage will also be discussed. PMID:18313407

  5. Engine

    SciTech Connect

    Shin, H.B.

    1984-02-28

    An internal combustion engine has a piston rack depending from each piston. This rack is connected to a power output shaft through a mechanical rectifier so that the power output shaft rotates in only one direction. A connecting rod is pivotally connected at one end to the rack and at the other end to the crank of a reduced function crankshaft so that the crankshaft rotates at the same angular velocity as the power output shaft and at the same frequency as the pistons. The crankshaft has a size, weight and shape sufficient to return the pistons back into the cylinders in position for the next power stroke.

  6. Proteome Profiling Reveals Potential Toxicity and Detoxification Pathways Following Exposure of BEAS-2B Cells to Engineered Titanium Dioxide Nanoparticles

    EPA Science Inventory

    Oxidative stress is known to play important roles in engineered nanomaterial induced cellular toxicity. However, the proteins and signaling pathways associated with the engineered nanomaterial mediated oxidative stress and toxicity are largely unknown. To identify these toxicity ...

  7. Engineering a Highly Hydrophilic PVDF Membrane via Binding TiO₂Nanoparticles and a PVA Layer onto a Membrane Surface.

    PubMed

    Qin, Aiwen; Li, Xiang; Zhao, Xinzhen; Liu, Dapeng; He, Chunju

    2015-04-29

    A highly hydrophilic PVDF membrane was fabricated through chemically binding TiO2 nanoparticles and a poly(vinyl alcohol) (PVA) layer onto a membrane surface simultaneously. The chemical composition of the modified membrane surface was determined by X-ray photoelectron spectroscopy, and the binding performance of TiO2 nanoparticles and the PVA layer was investigated by a rinsing test. The results indicated that the TiO2 nanoparticles were uniformly and strongly tailored onto the membrane surface, while the PVA layer was firmly attached onto the surface of TiO2 nanoparticles and the membrane by adsorption-cross-linking. The possible mechanisms during the modification process and filtration performance, i.e., water permeability and bovine serum albumin (BSA) rejection, were investigated as well. Furthermore, antifouling property was discussed through multicycles of BSA solution filtration tests, where the flux recovery ratio was significantly increased from 20.0% for pristine PVDF membrane to 80.5% for PVDF/TiO2/PVA-modified membrane. This remarkable promotion is mainly ascribed to the improvement of surface hydrophilicity, where the water contact angle of the membrane surface was decreased from 84° for pristine membrane to 24° for PVDF/TiO2/PVA membrane. This study presents a novel and varied strategy for immobilization of nanoparticles and PVA layer on substrate surface, which could be easily adapted for a variety of materials for surface modification. PMID:25806418

  8. Engineered nanoparticles of Efavirenz using methacrylate co-polymer (Eudragit-E100) and its biological effects in-vivo.

    PubMed

    Hari, B N Vedha; Narayanan, N; Dhevendaran, K; Ramyadevi, D

    2016-10-01

    Nanotechnology in drug delivery is explored widely to improve therapeutic efficacy and minimize undesirable effects of several anti-HIV drugs. Efavirenz is a non-nucleoside reverse transcriptase inhibitor, prescribed as first-line drug of choice for treatment of AIDS. It is poorly soluble and exhibits variable bioavailability hence, a high oral dose is recommended for therapy. The present work focuses on improving the dissolution and bioavailability of Efavirenz through nano drug delivery approach. Polymeric nanoparticles were developed using Eudragit E100 and characterized for size, stability, morphology, cytotoxicity (MTT assay in T-lymphatic (C8166) cell lines) and in-vivo biodistribution in mice models. The optimized nanoparticles exhibited average particle size of 110nm, zeta potential of -33mV and entrapment efficiency 99%. The SEM images displayed the formation of nano-size particles. The cell viability was significantly improved in the nanoparticles (99%) compared to pure drug (15%) at the concentration of 8μg/mL. The in-vivo biodistribution profile of the nanoparticles showed considerably higher drug concentration in serum and major organs, especially in the brain compared to the free drug. The optimized Efavirenz loaded nanoparticles clearly demonstrated an increase in dissolution, drug distribution, and bioavailability, which implies better control over the therapeutic dosing. PMID:27287151

  9. Adaptive neuro-fuzzy inference system (ANFIS) to predict CI engine parameters fueled with nano-particles additive to diesel fuel

    NASA Astrophysics Data System (ADS)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive neuro-fuzzy inference system (ANFIS) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For ANFIS modelling, Gaussian curve membership function (gaussmf) and 200 training epochs (iteration) were found to be optimum choices for training process. The results demonstrate that ANFIS is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve combustion of the fuel and reduce the exhaust emissions significantly.

  10. [Air-borne disease].

    PubMed

    Lameiro Vilariño, Carmen; del Campo Pérez, Victor M; Alonso Bürger, Susana; Felpeto Nodar, Irene; Guimarey Pérez, Rosa; Pérez Alvarellos, Alberto

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use. PMID:14705591

  11. Airborne forest fire research

    NASA Technical Reports Server (NTRS)

    Mattingly, G. S.

    1974-01-01

    The research relating to airborne fire fighting systems is reviewed to provide NASA/Langley Research Center with current information on the use of aircraft in forest fire operations, and to identify research requirements for future operations. A literature survey, interview of forest fire service personnel, analysis and synthesis of data from research reports and independent conclusions, and recommendations for future NASA-LRC programs are included.

  12. MLS airborne antenna research

    NASA Technical Reports Server (NTRS)

    Yu, C. L.; Burnside, W. D.

    1975-01-01

    The geometrical theory of diffraction was used to analyze the elevation plane pattern of on-aircraft antennas. The radiation patterns for basic elements (infinitesimal dipole, circumferential and axial slot) mounted on fuselage of various aircrafts with or without radome included were calculated and compared well with experimental results. Error phase plots were also presented. The effects of radiation patterns and error phase plots on the polarization selection for the MLS airborne antenna are discussed.

  13. Biophysical influence of airborne carbon nanomaterials on natural pulmonary surfactant.

    PubMed

    Valle, Russell P; Wu, Tony; Zuo, Yi Y

    2015-05-26

    Inhalation of nanoparticles (NP), including lightweight airborne carbonaceous nanomaterials (CNM), poses a direct and systemic health threat to those who handle them. Inhaled NP penetrate deep pulmonary structures in which they first interact with the pulmonary surfactant (PS) lining at the alveolar air-water interface. In spite of many research efforts, there is a gap of knowledge between in vitro biophysical study and in vivo inhalation toxicology since all existing biophysical models handle NP-PS interactions in the liquid phase. This technical limitation, inherent in current in vitro methodologies, makes it impossible to simulate how airborne NP deposit at the PS film and interact with it. Existing in vitro NP-PS studies using liquid-suspended particles have been shown to artificially inflate the no-observed adverse effect level of NP exposure when compared to in vivo inhalation studies and international occupational exposure limits (OELs). Here, we developed an in vitro methodology called the constrained drop surfactometer (CDS) to quantitatively study PS inhibition by airborne CNM. We show that airborne multiwalled carbon nanotubes and graphene nanoplatelets induce a concentration-dependent PS inhibition under physiologically relevant conditions. The CNM aerosol concentrations controlled in the CDS are comparable to those defined in international OELs. Development of the CDS has the potential to advance our understanding of how submicron airborne nanomaterials affect the PS lining of the lung. PMID:25929264

  14. Airborne field strength monitoring

    NASA Astrophysics Data System (ADS)

    Bredemeyer, J.; Kleine-Ostmann, T.; Schrader, T.; Münter, K.; Ritter, J.

    2007-06-01

    In civil and military aviation, ground based navigation aids (NAVAIDS) are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS) increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR) is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000) by the International Civil Aviation Organization (ICAO). One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz), the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA) accelerated method of moments (MoM) using a complex geometric model of the aircraft. First results will be presented in this paper.

  15. Mutagenicity of airborne particles.

    PubMed

    Chrisp, C E; Fisher, G L

    1980-09-01

    The physical and chemical properties of airborne particles are important for the interpretation of their potential biologic significance as genotoxic hazards. For polydisperse particle size distributions, the smallest, most respirable particles are generally the most mutagenic. Particulate collection for testing purposes should be designed to reduce artifact formation and allow condensation of mutagenic compounds. Other critical factors such as UV irradiation, wind direction, chemical reactivity, humidity, sample storage, and temperature of combustion are important. Application of chemical extraction methods and subsequent class fractionation techniques influence the observed mutagenic activity. Particles from urban air, coal fly ash, automobile and diesel exhaust, agricultural burning and welding fumes contain primarily direct-acting mutagens. Cigarette smoke condensate, smoke from charred meat and protein pyrolysates, kerosene soot and cigarette smoke condensates contain primarily mutagens which require metabolic activation. Fractionation coupled with mutagenicity testing indicates that the most potent mutagens are found in the acidic fractions of urban air, coal fly ash, and automobile diesel exhaust, whereas mutagens in rice straw smoke and cigarette smoke condensate are found primarily in the basic fractions. The interaction of the many chemical compounds in complex mixtures from airborne particles is likely to be important in determining mutagenic or comutagenic potentials. Because the mode of exposure is generally frequent and prolonged, the presence of tumor-promoting agents in complex mixtures may be a major factor in evaluation of the carcinogenic potential of airborne particles. PMID:7005667

  16. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  17. Recent advances in airborne terrestrial remote sensing with the NASA airborne visible/infrared imaging spectrometer (AVIRIS), airborne synthetic aperture radar (SAR), and thermal infrared multispectral scanner (TIMS)

    NASA Technical Reports Server (NTRS)

    Vane, Gregg; Evans, Diane L.; Kahle, Anne B.

    1989-01-01

    Significant progress in terrestrial remote sensing from the air has been made with three NASA-developed sensors that collectively cover the solar-reflected, thermal infrared, and microwave regions of the electromagnetic spectrum. These sensors are the airborne visible/infrared imaging spectrometer (AVIRIS), the thermal infrared mapping spectrometer (TIMS) and the airborne synthetic aperture radar (SAR), respectively. AVIRIS and SAR underwent extensive in-flight engineering testing in 1987 and 1988 and are scheduled to become operational in 1989. TIMS has been in operation for several years. These sensors are described.

  18. Interfacial engineering of nanoparticle systems: Assesment of electron transfer in inter and intrananoparticle photosystems as well as sensing applications

    NASA Astrophysics Data System (ADS)

    Phebus, Bruce Drury

    Electron transfer within nanochemical systems plays a key role in their uses. This body of work looks to better understand the conditions required for electron transport within these nanochemical systems and under what circumstances does it play a role in their use. Assessing electron transfer from aqueous graphene nanoparticles to aqueous ions through observation by quenching photoluminescence pointed to interesting requirements for transfer. Sensitivity was observed down to 1.6x10 -6 M for the most strongly quenching ions. More interesting though was a marked dependence on chemical hardness of the ions, with specific chemical hardness required to quench each graphene quantum dot species. Graphene quantum dots sourced from carbon fiber were observed to quench best with ions near that of 8.50 eV chemical hardness, like that of nickelous ions. Nitrogen doped graphene quantum dots were observed to quench best with ions near 7.70 eV in chemical hardness, like that of mercuric ions. The shift to a lower hardness is also noted in a shift toward lower excitation energy of the nanoparticles. For some ions concentration dependence was observed, with ions increasing PL emission initially then subsequently acting as quenchers. This behavior points to multiple quenching sites on the nanoparticles with different complexation values, some leading to stabilization of the PL emission when complexed. EDTA, ethylenediaminetetraacetic acid, was used as a complexing agent to assess possible recovery of emissions. EDTA was observed to complex ions and recovers some PL emission from some ions, with recovery dependent not only on quenching efficiency of the ion but the complexation constant. The most intriguing behavior was observed for aluminum ions which were observed to further quench with additions of EDTA after a critical point emission started to recover. We ascribe this behavior to multiple complexation sites on the nanoparticles with varied concentration and distinct roles in

  19. Airborne Submillimeter Spectroscopy

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1998-01-01

    This is the final technical report for NASA-Ames grant NAG2-1068 to Caltech, entitled "Airborne Submillimeter Spectroscopy", which extended over the period May 1, 1996 through January 31, 1998. The grant was funded by the NASA airborne astronomy program, during a period of time after the Kuiper Airborne Observatory was no longer operational. Instead. this funding program was intended to help develop instrument concepts and technology for the upcoming SOFIA (Stratospheric Observatory for Infrared Astronomy) project. SOFIA, which is funded by NASA and is now being carried out by a consortium lead by USRA (Universities Space Research Association), will be a 747 aircraft carrying a 2.5 meter diameter telescope. The purpose of our grant was to fund the ongoing development of sensitive heterodyne receivers for the submillimeter band (500-1200 GHz), using sensitive superconducting (SIS) detectors. In 1997 July we submitted a proposal to USRA to construct a heterodyne instrument for SOFIA. Our proposal was successful [1], and we are now continuing our airborne astronomy effort with funding from USRA. A secondary purpose of the NAG2-1068 grant was to continue the anaIN'sis of astronomical data collected with an earlier instrument which was flown on the NASA Kuiper Airborne Observatory (KAO). The KAO instrument and the astronomical studies which were carried out with it were supported primarily under another grant, NAG2-744, which extended over October 1, 1991 through Januarv 31, 1997. For a complete description of the astronomical data and its anailysis, we refer the reader to the final technical report for NAG2-744, which was submitted to NASA on December 1. 1997. Here we report on the SIS detector development effort for SOFIA carried out under NAG2-1068. The main result of this effort has been the demonstration of SIS mixers using a new superconducting material niobium titanium nitride (NbTiN), which promises to deliver dramatic improvements in sensitivity in the 700

  20. Airborne laser program revolutionizing airpower for the 21st century

    NASA Astrophysics Data System (ADS)

    Kanazawa, Tyle T.; Simon, Albert J.

    1998-09-01

    The Airborne Laser is an Air Force Major Defense Acquisition Program to develop and field an airborne high energy laser weapon system to provide speed-of-light lethal defense against hostile theater ballistic missiles in the boost phase. The Air Force believes the Airborne Laser has the potential to revolutionize air warfare. The advanced technologies being introduced by the Airborne Laser presents new and unique challenges for acquisition, operations, and supportability. This paper provides a program overview, and will cover the threat, system description, technology maturity, and acquisition strategy. The Airborne Laser program successfully passed through its Milestone 1 Defense Acquisition Board decision to proceed from Concept Design into Program Definition and Risk Reduction phase, to design, build, integrate, and conduct a lethal airborne demonstration against a boosting missile in 2002. Upon a successful lethal demonstration, the program will then proceed into Engineering and Manufacturing Development and Production. Initial Operation Capability will be in 2006 with three aircraft, and Full Operational Capability will be in 2008 with seven aircraft.

  1. Small airway epithelial cells exposure to printer-emitted engineered nanoparticles induces cellular effects on human microvascular endothelial cells in an alveolar-capillary co-culture model.

    PubMed

    Sisler, Jennifer D; Pirela, Sandra V; Friend, Sherri; Farcas, Mariana; Schwegler-Berry, Diane; Shvedova, Anna; Castranova, Vincent; Demokritou, Philip; Qian, Yong

    2015-01-01

    The printer is one of the most common office equipment. Recently, it was reported that toner formulations for printing equipment constitute nano-enabled products (NEPs) and contain engineered nanomaterials (ENMs) that become airborne during printing. To date, insufficient research has been performed to understand the potential toxicological properties of printer-emitted particles (PEPs) with several studies using bulk toner particles as test particles. These studies demonstrated the ability of toner particles to cause chronic inflammation and fibrosis in animal models. However, the toxicological implications of inhalation exposures to ENMs emitted from laser printing equipment remain largely unknown. The present study investigates the toxicological effects of PEPs using an in vitro alveolar-capillary co-culture model with Human Small Airway Epithelial Cells (SAEC) and Human Microvascular Endothelial Cells (HMVEC). Our data demonstrate that direct exposure of SAEC to low concentrations of PEPs (0.5 and 1.0 µg/mL) caused morphological changes of actin remodeling and gap formations within the endothelial monolayer. Furthermore, increased production of reactive oxygen species (ROS) and angiogenesis were observed in the HMVEC. Analysis of cytokine and chemokine levels demonstrates that interleukin (IL)-6 and MCP-1 may play a major role in the cellular communication observed between SAEC and HMVEC and the resultant responses in HMVEC. These data indicate that PEPs at low, non-cytotoxic exposure levels are bioactive and affect cellular responses in an alveolar-capillary co-culture model, which raises concerns for potential adverse health effects. PMID:25387250

  2. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  3. Airborne radioactive contamination monitoring

    SciTech Connect

    Whitley, C.R.; Adams, J.R.; Bounds, J.A.; MacArthur, D.W.

    1996-03-01

    Current technologies for the detection of airborne radioactive contamination do not provide real-time capability. Most of these techniques are based on the capture of particulate matter in air onto filters which are then processed in the laboratory; thus, the turnaround time for detection of contamination can be many days. To address this shortcoming, an effort is underway to adapt LRAD (Long-Range-Alpha-Detection) technology for real-time monitoring of airborne releases of alpa-emitting radionuclides. Alpha decays in air create ionization that can be subsequently collected on electrodes, producing a current that is proportional to the amount of radioactive material present. Using external fans on a pipe containing LRAD detectors, controlled samples of ambient air can be continuously tested for the presence of radioactive contamination. Current prototypes include a two-chamber model. Sampled air is drawn through a particulate filter and then through the first chamber, which uses an electrostatic filter at its entrance to remove ambient ionization. At its exit, ionization that occurred due to the presence of radon is collected and recorded. The air then passes through a length of pipe to allow some decay of short-lived radon species. A second chamber identical to the first monitors the remaining activity. Further development is necessary on air samples without the use of particulate filtering, both to distinguish ionization that can pass through the initial electrostatic filter on otherwise inert particulate matter from that produced through the decay of radioactive material and to separate both of these from the radon contribution. The end product could provide a sensitive, cost-effective, real-time method of determining the presence of airborne radioactive contamination.

  4. Airborne Raman lidar

    NASA Astrophysics Data System (ADS)

    Heaps, Wm. S.; Burris, J.

    1996-12-01

    We designed and tested an airborne lidar system using Raman scattering to make simultaneous measurements of methane, water vapor, and temperature in a series of flights on a NASA-operated C-130 aircraft. We present the results for methane detection, which show that the instrument has the requisite sensitivity to atmospheric trace gases. Ultimately these measurements can be used to examine the transport of chemically processed air from within the polar vortex to mid-latitudinal regions and the exchange of stratospheric air between tropical and mid-latitudinal regions.

  5. Airborne Oceanographic Lidar System

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The Airborne Oceanographic Lidar (AOL), a spatially scanning range-gated device installed on board a NASA C-54 aircraft, is described. The AOL system is capable of measuring topographical relief or water depth (bathymetry) with a range resolution of plus or minus 0.3 m in the vertical dimension. The system may also be used to measure fluorescent spectral signatures from 3500 to 8000 A with a resolution of 100 A. Potential applications of the AOL, including sea state measurements, water transparency assessments, oil spill identification, effluent identification and crop cover assessment are also mentioned.

  6. Layer-by-layer engineering fluorescent polyelectrolyte coated mesoporous silica nanoparticles as pH-sensitive nanocarriers for controlled release

    NASA Astrophysics Data System (ADS)

    Du, Pengcheng; Zhao, Xubo; Zeng, Jin; Guo, Jinshan; Liu, Peng

    2015-08-01

    Fluorescent core/shell composite has been fabricated by the layer-by-layer (LbL) assembly of the fluorescein isothiocyanate modified chitosan (CS-FITC) and sodium alginate (AL) onto the carboxyl modified mesoporous silica nanoparticles (MSN-COOH), followed by PEGylation. It exhibits stability in high salt-concentration media and the pH responsive fluorescent feature can be used for cell imaging. Furthermore, the modified MSN cores can enhance the DOX loading capacity and the multifunctional polyelectrolyte shell can adjust the drug release upon the media pH, showing a low leakage quantity at the neutral environment but significantly enhanced release at lower pH media mimicking the tumor environments. Therefore, the biocompatible fluorescent polyelectrolyte coated mesoporous silica nanoparticles (MSN-LBL-PEG) offer promise for tumor therapy.

  7. Use of a Rapid Cytotoxicity Screening Approach to Engineer a Safer Zinc Oxide Nanoparticle through Iron Doping

    PubMed Central

    George, Saji; Pokhrel, Suman; Xia, Tian; Gilbert, Benjamin; Ji, Zhaoxia; Schowalter, Marco; Rosenauer, Andreas; Damoiseaux, Robert; Bradley, Kenneth A; Mädler, Lutz; Nel, André E

    2014-01-01

    The establishment of verifiably safe nanotechnology requires the development of assessment tools to identify hazardous nanomaterial properties that could be modified to improve nanomaterial safety. While there is a lot of debate of what constitutes appropriate safety screening methods, one approach is to use the assessment of cellular injury pathways to collect knowledge about hazardous material properties that could lead to harm to humans and the environment. We demonstrate the use of a multi-parameter cytotoxicity assay that evaluates toxic oxidative stress to compare the effects of titanium dioxide (TiO2), cerium oxide (CeO2) and zinc oxide (ZnO) nanoparticles in bronchial epithelial and macrophage cell lines. The nanoparticles were chosen based on their volume of production and likelihood of spread to the environment. Among the materials, dissolution of ZnO nanoparticles and Zn2+ release were capable of ROS generation and activation of an integrated cytotoxic pathway that includes intracellular calcium flux, mitochondrial depolarization, and plasma membrane leakage. These responses were chosen based on the compatibility of the fluorescent dyes that contemporaneously assess their response characteristics by a semi-automated epifluorescence procedure. Purposeful reduction of ZnO cytotoxicity was achieved by iron doping, which changed the material matrix to slow Zn2+ release. In summary, we demonstrate the utility of a rapid throughput, integrated biological oxidative stress response pathway to perform hazard ranking of a small batch of metal oxide nanoparticles, in addition to showing how this assay can be used to improve nanosafety by decreasing ZnO dissolution through Fe doping. PMID:20043640

  8. Bio-mimetic surface engineering of plasmid-loaded nanoparticles for active intracellular trafficking by actin comet-tail motility.

    PubMed

    Ng, Chee Ping; Goodman, Thomas T; Park, In-Kyu; Pun, Suzie H

    2009-02-01

    Intracellular transport after endosomal escape presents one of the major barriers for efficient non-viral gene delivery because plasmid DNA and synthetic nanoparticulate carriers suffer from significantly restricted diffusion in the cytoplasm. We postulate that forces generated by actin polymerization, a mechanism used by several bacterial pathogens such as Listeria monocytogenes, can be harnessed to propel nanoparticles within the cytoplasm and thereby overcome diffusional limitations associated with gene transport in the cell cytoplasm. In this work, we synthesized and characterized plasmid DNA-containing nanoparticles modified with ActA protein, the single protein in L. monocytogenes responsible for activating actin polymerization and initiating actin comet-tail propulsion. The motility of the ActA-modified nanoparticles was assessed in Xenopus laevis cytoplasmic extract supplemented with fluorescently labeled actin. Nanoparticle motility was monitored using multi-color, time-lapse fluorescence microscopy for the formation of actin comet tails attached to the fluorescently labeled vehicle. We observed particle motility with velocities approximately 0.06 microm/s with anionic-charged plasmid carriers formed from either poly(lactic-co-glycolic acid) (PLGA) or 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes, but interestingly not with cationic particles assembled by encapsulation of plasmid with either polyethylenimine (PEI) or 1,2-dioleoyl-3-trimethylammonium-propane/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOTAP/DOPE) lipids. Control particles coated with albumin instead of ActA also showed no motility. Taken together, we have demonstrated the feasibility of translating the comet-tail propulsion mechanism to synthetic drug carriers as a potential approach to overcome intracellular transport barriers, and also have identified appropriate gene delivery systems that can be employed for this mechanism. PMID:19046764

  9. Dipole-excited surface plasmons in metallic nanoparticles: Engineering decay dynamics within the discrete-dipole approximation

    NASA Astrophysics Data System (ADS)

    D'Agostino, Stefania; Della Sala, Fabio; Andreani, Lucio Claudio

    2013-05-01

    A theoretical control of the electromagnetic coupling between localized surface plasmons and pointlike sources of radiation is a relevant topic in nanoscience and nanophotonics. In this paper a numerical approach based on the discrete dipole approximation is presented as a practical and reliable computational tool to study the decay dynamics of a dipole when it is located in the near proximities of metallic nanoparticles whose shapes do not allow a fully analytical treatment. The method is first applied to Ag nanospheres and nanoshells, which represent two analytically solvable cases, and it is shown to lead to a very good agreement with exact results. The approach is then used to consider the response, in terms of perturbations induced on the radiative and nonradiative decay rates, of elongated nanoparticles, like Ag prolate spheroids and nanocones. Results demonstrate how the optical response of conically shaped nanoparticles can be affected by the distance and the orientation of the emitter of radiation, as well as by other geometrical parameters. The particular symmetry of these plasmonic objects results in peculiar features: the absorption efficiencies of the modes depend on the distance of the source of radiation in a counterintuitive way, and this is explained in terms of the excited charge density distributions. The possibility to simulate arbitrary-shaped nanostructures and several dipole-metal configurations presented here, could thus open new avenues for an aware use of surface plasmons in fluorescence spectroscopy applications or single photon emission studies.

  10. Titanium dioxide nanoparticles cause genotoxicity in human lung epithelial cells

    EPA Science Inventory

    The use of engineered nanoparticles in consumer products is steadily increasing. However, the health effects of exposure to these nanoparticles are not thoroughly understood. This study investigated the genotoxicity of six titanium dioxide and two cerium oxide nanoparticles of va...

  11. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown. PMID:23406937

  12. Airborne ballistic camera tracking systems

    NASA Technical Reports Server (NTRS)

    Redish, W. L.

    1976-01-01

    An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

  13. Airborne transmission of lyssaviruses.

    PubMed

    Johnson, N; Phillpotts, R; Fooks, A R

    2006-06-01

    In 2002, a Scottish bat conservationist developed a rabies-like disease and subsequently died. This was caused by infection with European bat lyssavirus 2 (EBLV-2), a virus closely related to Rabies virus (RABV). The source of this infection and the means of transmission have not yet been confirmed. In this study, the hypothesis that lyssaviruses, particularly RABV and the bat variant EBLV-2, might be transmitted via the airborne route was tested. Mice were challenged via direct introduction of lyssavirus into the nasal passages. Two hours after intranasal challenge with a mouse-adapted strain of RABV (Challenge Virus Standard), viral RNA was detectable in the tongue, lungs and stomach. All of the mice challenged by direct intranasal inoculation developed disease signs by 7 days post-infection. Two out of five mice challenged by direct intranasal inoculation of EBLV-2 developed disease between 16 and 19 days post-infection. In addition, a simple apparatus was evaluated in which mice could be exposed experimentally to infectious doses of lyssavirus from an aerosol. Using this approach, mice challenged with RABV, but not those challenged with EBLV-2, were highly susceptible to infection by inhalation. These data support the hypothesis that lyssaviruses, and RABV in particular, can be spread by airborne transmission in a dose-dependent manner. This could present a particular hazard to personnel exposed to aerosols of infectious RABV following accidental release in a laboratory environment. PMID:16687600

  14. Transport and retention of engineered Al2O3, TiO2, and SiO2 nanoparticles through various sedimentary rocks

    PubMed Central

    Esfandyari Bayat, Ali; Junin, Radzuan; Shamshirband, Shahaboddin; Tong Chong, Wen

    2015-01-01

    Engineered aluminum oxide (Al2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2) nanoparticles (NPs) are utilized in a broad range of applications; causing noticeable quantities of these materials to be released into the environment. Issues of how and where these particles are distributed into the subsurface aquatic environment remain as major challenges for those in environmental engineering. In this study, transport and retention of Al2O3, TiO2, and SiO2 NPs through various saturated porous media were investigated. Vertical columns were packed with quartz-sand, limestone, and dolomite grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolet-visible spectrophotometer. It was found that Al2O3 and TiO2 NPs are easily transported through limestone and dolomite porous media whereas NPs recoveries were achieved two times higher than those found in the quartz-sand. The highest and lowest SiO2-NPs recoveries were also achieved from the quartz-sand and limestone columns, respectively. The experimental results closely replicated the general trends predicted by the filtration and DLVO calculations. Overall, NPs mobility through a porous medium was found to be strongly dependent on NP surface charge, NP suspension stability against deposition, and porous medium surface charge and roughness. PMID:26373598

  15. Transport and retention of engineered Al2O3, TiO2, and SiO2 nanoparticles through various sedimentary rocks.

    PubMed

    Bayat, Ali Esfandyari; Junin, Radzuan; Shamshirband, Shahaboddin; Chong, Wen Tong

    2015-01-01

    Engineered aluminum oxide (Al2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2) nanoparticles (NPs) are utilized in a broad range of applications; causing noticeable quantities of these materials to be released into the environment. Issues of how and where these particles are distributed into the subsurface aquatic environment remain as major challenges for those in environmental engineering. In this study, transport and retention of Al2O3, TiO2, and SiO2 NPs through various saturated porous media were investigated. Vertical columns were packed with quartz-sand, limestone, and dolomite grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolet-visible spectrophotometer. It was found that Al2O3 and TiO2 NPs are easily transported through limestone and dolomite porous media whereas NPs recoveries were achieved two times higher than those found in the quartz-sand. The highest and lowest SiO2-NPs recoveries were also achieved from the quartz-sand and limestone columns, respectively. The experimental results closely replicated the general trends predicted by the filtration and DLVO calculations. Overall, NPs mobility through a porous medium was found to be strongly dependent on NP surface charge, NP suspension stability against deposition, and porous medium surface charge and roughness. PMID:26373598

  16. Transport and retention of engineered Al2O3, TiO2, and SiO2 nanoparticles through various sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Esfandyari Bayat, Ali; Junin, Radzuan; Shamshirband, Shahaboddin; Tong Chong, Wen

    2015-09-01

    Engineered aluminum oxide (Al2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2) nanoparticles (NPs) are utilized in a broad range of applications; causing noticeable quantities of these materials to be released into the environment. Issues of how and where these particles are distributed into the subsurface aquatic environment remain as major challenges for those in environmental engineering. In this study, transport and retention of Al2O3, TiO2, and SiO2 NPs through various saturated porous media were investigated. Vertical columns were packed with quartz-sand, limestone, and dolomite grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolet-visible spectrophotometer. It was found that Al2O3 and TiO2 NPs are easily transported through limestone and dolomite porous media whereas NPs recoveries were achieved two times higher than those found in the quartz-sand. The highest and lowest SiO2-NPs recoveries were also achieved from the quartz-sand and limestone columns, respectively. The experimental results closely replicated the general trends predicted by the filtration and DLVO calculations. Overall, NPs mobility through a porous medium was found to be strongly dependent on NP surface charge, NP suspension stability against deposition, and porous medium surface charge and roughness.

  17. Processor architecture for airborne SAR systems

    NASA Technical Reports Server (NTRS)

    Glass, C. M.

    1983-01-01

    Digital processors for spaceborne imaging radars and application of the technology developed for airborne SAR systems are considered. Transferring algorithms and implementation techniques from airborne to spaceborne SAR processors offers obvious advantages. The following topics are discussed: (1) a quantification of the differences in processing algorithms for airborne and spaceborne SARs; and (2) an overview of three processors for airborne SAR systems.

  18. Evaluation of meteorological airborne Doppler radar

    NASA Technical Reports Server (NTRS)

    Hildebrand, P. H.; Mueller, C. K.

    1984-01-01

    This paper will discuss the capabilities of airborne Doppler radar for atmospheric sciences research. The evaluation is based on airborne and ground based Doppler radar observations of convective storms. The capability of airborne Doppler radar to measure horizontal and vertical air motions is evaluated. Airborne Doppler radar is shown to be a viable tool for atmospheric sciences research.

  19. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  20. Airborne Wind Turbine

    SciTech Connect

    2010-09-01

    Broad Funding Opportunity Announcement Project: Makani Power is developing an Airborne Wind Turbine (AWT) that eliminates 90% of the mass of a conventional wind turbine and accesses a stronger, more consistent wind at altitudes of near 1,000 feet. At these altitudes, 85% of the country can offer viable wind resources compared to only 15% accessible with current technology. Additionally, the Makani Power wing can be economically deployed in deep offshore waters, opening up a resource which is 4 times greater than the entire U.S. electrical generation capacity. Makani Power has demonstrated the core technology, including autonomous launch, land, and power generation with an 8 meter wingspan, 20 kW prototype. At commercial scale, Makani Power aims to develop a 600 kW, 28 meter wingspan product capable of delivering energy at an unsubsidized cost competitive with coal, the current benchmark for low-cost power.

  1. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  2. Electrophoretic Deposition of Dexamethasone-Loaded Mesoporous Silica Nanoparticles onto Poly(L-Lactic Acid)/Poly(ε-Caprolactone) Composite Scaffold for Bone Tissue Engineering.

    PubMed

    Qiu, Kexin; Chen, Bo; Nie, Wei; Zhou, Xiaojun; Feng, Wei; Wang, Weizhong; Chen, Liang; Mo, Xiumei; Wei, Youzhen; He, Chuanglong

    2016-02-17

    The incorporation of microcarriers as drug delivery vehicles into polymeric scaffold for bone regeneration has aroused increasing interest. In this study, the aminated mesoporous silica nanoparticles (MSNs-NH2) were prepared and used as microcarriers for dexamethasone (DEX) loading. Poly(l-lactic acid)/poly(ε-caprolactone) (PLLA/PCL) nanofibrous scaffold was fabricated via thermally induced phase separation (TIPS) and served as template, onto which the drug-loaded MSNs-NH2 nanoparticles were deposited by electrophoretic deposition (EPD). The physicochemical and release properties of the prepared scaffolds (DEX@MSNs-NH2/PLLA/PCL) were examined, and their osteogenic activities were also evaluated through in vitro and in vivo studies. The release of DEX from the scaffolds revealed an initial rapid release followed by a slower and sustained one. The in vitro results indicated that the DEX@MSNs-NH2/PLLA/PCL scaffold exhibited good biocompatibility to rat bone marrow-derived mesenchymal stem cells (BMSCs). Also, BMSCs cultured on the DEX@MSNs-NH2/PLLA/PCL scaffold exhibited a higher degree of osteogenic differentiation than those cultured on PLLA/PCL and MSNs-NH2/PLLA/PCL scaffolds, in terms of alkaline phosphatase (ALP) activity, mineralized matrix formation, and osteocalcin (OCN) expression. Furthermore, the in vivo results in a calvarial defect model of Sprague-Dawley (SD) rats demonstrated that the DEX@MSNs-NH2/PLLA/PCL scaffold could significantly promote calvarial defect healing compared with the PLLA/PCL scaffold. Thus, the EPD technique provides a convenient way to incorporate osteogenic agents-containing microcarriers to polymer scaffold, and thus, prepared composite scaffold could be a potential candidate for bone tissue engineering application due to its capacity for delivery of osteogenic agents. PMID:26736029

  3. Nanoparticles and direct immunosuppression.

    PubMed

    Ngobili, Terrika A; Daniele, Michael A

    2016-05-01

    Targeting the immune system with nanomaterials is an intensely active area of research. Specifically, the capability to induce immunosuppression is a promising complement for drug delivery and regenerative medicine therapies. Many novel strategies for immunosuppression rely on nanoparticles as delivery vehicles for small-molecule immunosuppressive compounds. As a consequence, efforts in understanding the mechanisms in which nanoparticles directly interact with the immune system have been overshadowed. The immunological activity of nanoparticles is dependent on the physiochemical properties of the nanoparticles and its subsequent cellular internalization. As the underlying factors for these reactions are elucidated, more nanoparticles may be engineered and evaluated for inducing immunosuppression and complementing immunosuppressive drugs. This review will briefly summarize the state-of-the-art and developments in understanding how nanoparticles induce immunosuppressive responses, compare the inherent properties of nanomaterials which induce these immunological reactions, and comment on the potential for using nanomaterials to modulate and control the immune system. PMID:27229901

  4. Optical engineering of uniformly decorated graphene oxide nanoflakes via in situ growth of silver nanoparticles with enhanced plasmonic resonance.

    PubMed

    Yuan, Kai; Chen, Lie; Chen, Yiwang

    2014-12-10

    A nanocomposite of silver-nanoparticle-decorated graphene oxide (GO-Ag NPs), enhanced by the surface plasmon resonance (SPR) effect, improved the performance of polymer solar cells (PSCs). The GO-Ag NPs were fabricated in situ via ultraviolet (UV) irradiation (254 nm) of GO and an aqueous solution of AgNO3. The photoexcited GO accelerated reduction of Ag(+) ions into silver nanoparticles (Ag NPs) upon UV irradiation, and the Ag NPs spontaneously deposited on the GO nanoflakes because the numerous functional groups on GO enable efficient adsorption of Ag(+) ions and Ag NPs via electrostatic interactions. The strong coupling between the SPR effect of GO-Ag NPs and incident light offers the probability of improved light absorption and corresponding exciton generation rate with enhanced charge collection, resulting in significant enhancement in short-circuit current density and power conversion efficiency (PCE). Therefore, the PCE of PSCs based on poly[4,8-bis(2-ethylhexylthiophene-5-yl)-benzo[1,2-b:4,5-b]dithiophene-2,6-diyl]-alt-[2-(2-ethylhexanoyl)thieno[3,4-b]thiophen-4,6-diyl] and [6,6]-phenyl C71-butyric acid methyl ester has been substantially elevated to 7.54% from 6.58% by introducing GO-Ag NPs at the indium tin oxide/poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid interface. In addition, the excellent properties of GO-Ag NPs, including its simple preparation, processability in aqueous solution, cost-effectiveness, and sustainability, make it suitable for the roll-to-roll manufacturing of PSCs. PMID:25389764

  5. Limitations and relative utility of screening assays to assess engineered nanoparticle toxicity in a human cell line

    SciTech Connect

    Monteiro-Riviere, N.A.; Inman, A.O.; Zhang, L.W.

    2009-01-15

    Single-walled carbon nanotubes (SWCNT), fullerenes (C{sub 60}), carbon black (CB), nC{sub 60}, and quantum dots (QD) have been studied in vitro to determine their toxicity in a number of cell types. Here, we report that classical dye-based assays such as MTT and neutral red (NR) that determine cell viability produce invalid results with some NM (nanomaterials) due to NM/dye interactions and/or NM adsorption of the dye/dye products. In this study, human epidermal keratinocytes (HEK) were exposed in vitro to CB, SWCNT, C{sub 60}, nC{sub 60}, and QD to assess viability with calcein AM (CAM), Live/Dead (LD), NR, MTT, Celltiter 96 AQueous One (96 AQ), alamar Blue (aB), Celltiter-Blue (CTB), CytoTox One{sup TM} (CTO), and flow cytometry. In addition, trypan blue (TB) was quantitated by light microscopy. Assay linearity (R{sup 2} value) was determined with HEK plated at concentrations from 0 to 25,000 cells per well in 96-well plates. HEK were treated with serial dilutions of each NM for 24 h and assessed with each of the viability assays. TB, CAM and LD assays, which depend on direct staining of living and/or dead cells, were difficult to interpret due to physical interference of the NM with cells. Results of the dye-based assays varied a great deal, depending on the interactions of the dye/dye product with the carbon nanomaterials (CNM). Results show the optimal high throughput assay for use with carbon and noncarbon NM was 96 AQ. This study shows that, unlike small molecules, CNM interact with assay markers to cause variable results with classical toxicology assays and may not be suitable for assessing nanoparticle cytotoxicity. Therefore, more than one assay may be required when determining nanoparticle toxicity for risk assessment.

  6. Airborne Particulate Threat Assessment

    SciTech Connect

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  7. Airborne GLM Simulator (FEGS)

    NASA Astrophysics Data System (ADS)

    Quick, M.; Blakeslee, R. J.; Christian, H. J., Jr.; Stewart, M. F.; Podgorny, S.; Corredor, D.

    2015-12-01

    Real time lightning observations have proven to be useful for advanced warning and now-casting of severe weather events. In anticipation of the launch of the Geostationary Lightning Mapper (GLM) onboard GOES-R that will provide continuous real time observations of total (both cloud and ground) lightning, the Fly's Eye GLM Simulator (FEGS) is in production. FEGS is an airborne instrument designed to provide cal/val measurements for GLM from high altitude aircraft. It consists of a 5 x 5 array of telescopes each with a narrow passband filter to isolate the 777.4 nm neutral oxygen emission triplet radiated by lightning. The telescopes will measure the optical radiance emitted by lightning that is transmitted through the cloud top with a temporal resolution of 10 μs. When integrated on the NASA ER-2 aircraft, the FEGS array with its 90° field-of-view will observe a cloud top area nearly equal to a single GLM pixel. This design will allow FEGS to determine the temporal and spatial variation of light that contributes to a GLM event detection. In addition to the primary telescope array, the instrument includes 5 supplementary optical channels that observe alternate spectral emission features and will enable the use of FEGS for interesting lightning physics applications. Here we present an up-to-date summary of the project and a description of its scientific applications.

  8. Airborne rescue system

    NASA Technical Reports Server (NTRS)

    Haslim, Leonard A. (Inventor)

    1991-01-01

    The airborne rescue system includes a boom with telescoping members for extending a line and collar to a rescue victim. The boom extends beyond the tip of the helicopter rotor so that the victim may avoid the rotor downwash. The rescue line is played out and reeled in by winch. The line is temporarily retained under the boom. When the boom is extended, the rescue line passes through clips. When the victim dons the collar and the tension in the line reaches a predetermined level, the clips open and release the line from the boom. Then the rescue line can form a straight line between the victim and the winch, and the victim can be lifted to the helicopter. A translator is utilized to push out or pull in the telescoping members. The translator comprises a tape and a rope. Inside the telescoping members the tape is curled around the rope and the tape has a tube-like configuration. The tape and rope are provided from supply spools.

  9. Enhanced In Vivo Tumor Detection by Active Tumor Cell Targeting Using Multiple Tumor Receptor-Binding Peptides Presented on Genetically Engineered Human Ferritin Nanoparticles.

    PubMed

    Kwon, Koo Chul; Ko, Ho Kyung; Lee, Jiyun; Lee, Eun Jung; Kim, Kwangmeyung; Lee, Jeewon

    2016-08-01

    Human ferritin heavy-chain nanoparticle (hFTH) is genetically engineered to present tumor receptor-binding peptides (affibody and/or RGD-derived cyclic peptides, named 4CRGD here) on its surface. The affibody and 4CRGD specifically and strongly binds to human epidermal growth factor receptor I (EGFR) and human integrin αvβ3, respectively, which are overexpressed on various tumor cells. Through in vitro culture of EGFR-overexpressing adenocarcinoma (MDA-MB-468) and integrin-overexpressing glioblastoma cells (U87MG), it is clarified that specific interactions between receptors on tumor cells and receptor-binding peptides on engineered hFTH is critical in active tumor cell targeting. After labeling with the near-infrared fluorescence dye (Cy5.5) and intravenouse injection into MDA-MB-468 or U87MG tumor-bearing mice, the recombinant hFTHs presenting either peptide or both of affibody and 4CRGD are successfully delivered to and retained in the tumor for a prolonged period of time. In particular, the recombinant hFTH presenting both affibody and 4CRGD notably enhances in vivo detection of U87MG tumors that express heterogeneous receptors, integrin and EGFR, compared to the other recombinant hFTHs presenting either affibody or 4CRGD only. Like affibody and 4CRGD used in this study, other multiple tumor receptor-binding peptides can be also genetically introduced to the hFTH surface for actively targeting of in vivo tumors with heterogenous receptors. PMID:27356892

  10. Engineered silver nanoparticles are sensed at the plasma membrane and dramatically modify the physiology of Arabidopsis thaliana plants.

    PubMed

    Sosan, Arifa; Svistunenko, Dimitri; Straltsova, Darya; Tsiurkina, Katsiaryna; Smolich, Igor; Lawson, Tracy; Subramaniam, Sunitha; Golovko, Vladimir; Anderson, David; Sokolik, Anatoliy; Colbeck, Ian; Demidchik, Vadim

    2016-01-01

    Silver nanoparticles (Ag NPs) are the world's most important nanomaterial and nanotoxicant. The aim of this study was to determine the early stages of interactions between Ag NPs and plant cells, and to investigate their physiological roles. We have shown that the addition of Ag NPs to cultivation medium, at levels above 300 mg L(-1) , inhibited Arabidopsis thaliana root elongation and leaf expansion. This also resulted in decreased photosynthetic efficiency and the extreme accumulation of Ag in tissues. Acute application of Ag NPs induced a transient elevation of [Ca(2+) ]cyt and the accumulation of reactive oxygen species (ROS; partially generated by NADPH oxidase). Whole-cell patch-clamp measurements on root cell protoplasts demonstrated that Ag NPs slightly inhibited plasma membrane K(+) efflux and Ca(2+) influx currents, or caused membrane breakdown; however, in excised outside-out patches, Ag NPs activated Gd(3+) -sensitive Ca(2+) influx channels with unitary conductance of approximately 56 pS. Bulk particles did not modify the plasma membrane currents. Tests with electron paramagnetic resonance spectroscopy showed that Ag NPs were not able to catalyse hydroxyl radical generation, but that they directly oxidized the major plant antioxidant, l-ascorbic acid. Overall, the data presented shed light on mechanisms of the impact of nanosilver on plant cells, and show that these include the induction of classical stress signalling reactions (mediated by [Ca(2+) ]cyt and ROS) and a specific effect on the plasma membrane conductance and the reduced ascorbate. PMID:26676841

  11. Interfacial Engineering of Bimetallic Ag/Pt Nanoparticles on Reduced Graphene Oxide Matrix for Enhanced Antimicrobial Activity.

    PubMed

    Zhang, Mei; Zhao, Yanhua; Yan, Li; Peltier, Raoul; Hui, Wenli; Yao, Xi; Cui, Yali; Chen, Xianfeng; Sun, Hongyan; Wang, Zuankai

    2016-04-01

    Environmental biofouling caused by the formation of biofilm has been one of the most urgent global concerns. Silver nanoparticles (NPs), owing to their wide-spectrum antimicrobial property, have been widely explored to combat biofilm, but their extensive use has raised growing concern because they persist in the environment. Here we report a novel hybrid nanocomposite that imparts enhanced antimicrobial activity and low cytotoxicity yet with the advantage of reduced silver loading. The nanocomposite consists of Pt/Ag bimetallic NPs (BNPs) decorated on the porous reduced graphene oxide (rGO) nanosheets. We demonstrate that the enhanced antimicrobial property against Escherichia coli is ascribed to the intricate control of the interfaces between metal compositions, rGO matrix, and bacteria, where the BNPs lead to a rapid release of silver ions, and the trapping of bacteria by the porous rGO matrix further provides high concentration silver ion sites for efficient bacteria-bactericide interaction. We envision that our facile approach significantly expands the design space for the creation of silver-based antimicrobial materials to achieve a wide spectrum of functionalities. PMID:27007980

  12. Development of a gene-activated scaffold platform for tissue engineering applications using chitosan-pDNA nanoparticles on collagen-based scaffolds.

    PubMed

    Raftery, Rosanne M; Tierney, Erica G; Curtin, Caroline M; Cryan, Sally-Ann; O'Brien, Fergal J

    2015-07-28

    Biomaterial scaffolds that support cell infiltration and tissue formation can also function as platforms for the delivery of therapeutics such as drugs, proteins, and genes. As burst release of supraphysiological quantities of recombinant proteins can result in adverse side effects, the objective of this study was to explore the potential of a series of collagen-based scaffolds, developed in our laboratory, as gene-activated scaffold platforms with potential in a range of tissue engineering applications. The potential of chitosan, a biocompatible material derived from the shells of crustaceans, as a gene delivery vector was assessed using mesenchymal stem cells (MSCs). A transfection efficiency of >45% is reported which is similar to what is achieved with polyethyleneimine (PEI), a non-viral gold standard vector, without causing cytotoxic side effects. When the optimised chitosan nanoparticles were incorporated into a series of collagen-based scaffolds, sustained transgene expression from MSCs seeded on the scaffolds was maintained for up to 28days and interestingly the composition of the scaffold had an effect on transfection efficiency. These results demonstrate that by simply varying the scaffold composition and the gene (or combinations thereof) chosen; the system has potential for a myriad of therapeutic applications. PMID:25982680

  13. Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

    DOE PAGESBeta

    Lucachick, Glenn; Curran, Scott; Storey, John Morse; Prikhodko, Vitaly Y.; Northrop, William F.

    2016-03-10

    Our work explores the volatility of particles produced from two diesel low temperature combustion (LTC) modes proposed for high-efficiency compression ignition engines. It also explores mechanisms of particulate formation and growth upon dilution in the near-tailpipe environment. Moreover, the number distribution of exhaust particles from low- and mid-load dual-fuel reactivity controlled compression ignition (RCCI) and single-fuel premixed charge compression ignition (PPCI) modes were experimentally studied over a gradient of dilution temperature. Particle volatility of select particle diameters was investigated using volatility tandem differential mobility analysis (V-TDMA). Evaporation rates for exhaust particles were compared with V-TDMA results for candidate pure n-alkanesmore » to identify species with similar volatility characteristics. The results show that LTC particles are mostly comprised of material with volatility similar to engine oil alkanes. V-TDMA results were used as inputs to an aerosol condensation and evaporation model to support the finding that smaller particles in the distribution are comprised of lower volatility material than large particles under primary dilution conditions. Although the results show that saturation levels are high enough to drive condensation of alkanes onto existing particles under the dilution conditions investigated, they are not high We conclude that observed particles from LTC operation must grow from low concentrations of highly non-volatile compounds present in the exhaust.« less

  14. Enhancing nerve regeneration in the peripheral nervous system using polymeric scaffolds, stem cell engineering and nanoparticle delivery system

    NASA Astrophysics Data System (ADS)

    Sharma, Anup Dutt

    Peripheral nerve regeneration is a complex biological process responsible for regrowth of neural tissue following a nerve injury. The main objective of this project was to enhance peripheral nerve regeneration using interdisciplinary approaches involving polymeric scaffolds, stem cell therapy, drug delivery and high content screening. Biocompatible and biodegradable polymeric materials such as poly (lactic acid) were used for engineering conduits with micropatterns capable of providing mechanical support and orientation to the regenerating axons and polyanhydrides for fabricating nano/microparticles for localized delivery of neurotrophic growth factors and cytokines at the site of injury. Transdifferentiated bone marrow stromal cells or mesenchymal stem cells (MSCs) were used as cellular replacements for lost native Schwann cells (SCs) at the injured nerve tissue. MSCs that have been transdifferentiated into an SC-like phenotype were tested as a substitute for the myelinating SCs. Also, genetically modified MSCs were engineered to hypersecrete brain- derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) to secrete therapeutic factors which Schwann cell secrete. To further enhance the regeneration, nerve growth factor (NGF) and interleukin-4 (IL4) releasing polyanhydrides nano/microparticles were fabricated and characterized in vitro for their efficacy. Synergistic use of these proposed techniques was used for fabricating a multifunctional nerve regeneration conduit which can be used as an efficient tool for enhancing peripheral nerve regeneration.

  15. Airborne Laser Polar Nephelometer

    NASA Technical Reports Server (NTRS)

    Grams, Gerald W.

    1973-01-01

    A polar nephelometer has been developed at NCAR to measure the angular variation of the intensity of light scattered by air molecules and particles. The system has been designed for airborne measurements using outside air ducted through a 5-cm diameter airflow tube; the sample volume is that which is common to the intersection of a collimated source beam and the detector field of view within the airflow tube. The source is a linearly polarized helium-neon laser beam. The optical system defines a collimated field-of-view (0.5deg half-angle) through a series of diaphragms located behind a I72-mm focal length objective lens. A photomultiplier tube is located immediately behind an aperture in the focal plane of the objective lens. The laser beam is mechanically chopped (on-off) at a rate of 5 Hz; a two-channel pulse counter, synchronized to the laser output, measures the photomultiplier pulse rate with the light beam both on and off. The difference in these measured pulse rates is directly proportional to the intensity of the scattered light from the volume common to the intersection of the laser beam and the detector field-of-view. Measurements can be made at scattering angles from 15deg to 165deg with reference to the direction of propagation of the light beam. Intermediate angles are obtained by selecting the angular increments desired between these extreme angles (any multiple of 0.1deg can be selected for the angular increment; 5deg is used in normal operation). Pulses provided by digital circuits control a stepping motor which sequentially rotates the detector by pre-selected angular increments. The synchronous photon-counting system automatically begins measurement of the scattered-light intensity immediately after the rotation to a new angle has been completed. The instrument has been flown on the NASA Convair 990 airborne laboratory to obtain data on the complex index of refraction of atmospheric aerosols. A particle impaction device is operated simultaneously

  16. Surface Engineering of Polypropylene Membranes with Carbonic Anhydrase-Loaded Mesoporous Silica Nanoparticles for Improved Carbon Dioxide Hydration.

    PubMed

    Yong, Joel K J; Cui, Jiwei; Cho, Kwun Lun; Stevens, Geoff W; Caruso, Frank; Kentish, Sandra E

    2015-06-01

    Carbonic anhydrase (CA) is a native enzyme that facilitates the hydration of carbon dioxide into bicarbonate ions. This study reports the fabrication of thin films of active CA enzyme onto a porous membrane substrate using layer-by-layer (LbL) assembly. Deposition of multilayer films consisting of polyelectrolytes and CA was monitored by quartz crystal microgravimetry, while the enzymatic activity was assayed according to the rates of p-nitrophenylacetate (p-NPA) hydrolysis and CO2 hydration. The fabrication of the films onto a nonporous glass substrate showed CO2 hydration rates of 0.52 ± 0.09 μmol cm(-2) min(-1) per layer of bovine CA and 2.6 ± 0.7 μmol cm(-2) min(-1) per layer of a thermostable microbial CA. The fabrication of a multilayer film containing the microbial CA on a porous polypropylene membrane increased the hydration rate to 5.3 ± 0.8 μmol cm(-2) min(-1) per layer of microbial CA. The addition of mesoporous silica nanoparticles as a film layer prior to enzyme adsorption was found to increase the activity on the polypropylene membranes even further to a rate of 19 ± 4 μmol cm(-2) min(-1) per layer of microbial CA. The LbL treatment of these membranes increased the mass transfer resistance of the membrane but decreased the likelihood of membrane pore wetting. These results have potential application in the absorption of carbon dioxide from combustion flue gases into aqueous solvents using gas-liquid membrane contactors. PMID:25984966

  17. Exposure of Paracentrotus lividus male gametes to engineered nanoparticles affects skeletal bio-mineralization processes and larval plasticity.

    PubMed

    Gambardella, Chiara; Ferrando, Sara; Morgana, Silvia; Gallus, Lorenzo; Ramoino, Paola; Ravera, Silvia; Bramini, Mattia; Diaspro, Alberto; Faimali, Marco; Falugi, Carla

    2015-01-01

    The aim of this study is to contribute to the understanding of the mechanisms underlying nanoparticle (NP)-induced embryotoxicity in aquatic organisms. We previously demonstrated that exposure of male gametes to NPs causes non-dose-dependent skeletal damage in sea urchin (Paracentrotus lividus) larvae. In the present study, the molecular mechanisms responsible for these anomalies in sea urchin development from male gametes exposed to cobalt (Co), titanium dioxide (TiO2) and silver (Ag) NPs were investigated by histochemical, immunohistochemical and Western blot analyses. P. lividus sperm were exposed to different NP concentrations (from 0.0001 to 1 mg/L). The distribution of molecules related to skeletogenic cell identification, including ID5 immunoreactivity (IR), wheat germ agglutinin (WGA) affinity and fibronectin (FN) IR, were investigated by confocal laser scanning microscopy at the gastrula (24 h) and pluteus (72 h) stages. Our results identified a spatial correspondence among PMCs, ID5 IR and WGA affinity sites. The altered FN pattern suggests that it is responsible for the altered skeletogenic cell migration, while the Golgi apparatus of the skeletogenic cells, denoted by their WGA affinity, shows different aspects according to the degree of anomalies caused by NP concentrations. The ID5 IR, a specific marker of skeletogenic cells in sea urchin embryos (in particular of the msp130 protein responsible for Ca(2+) and Mg(2+) mineralization), localized in the cellular strands prefiguring the skeletal rods in the gastrula stage and, in the pluteus stage, was visible according to the degree of mineralization of the skeleton. In conclusion, the present study suggests that the investigated NPs suspended in seawater interfere with the bio-mineralization processes in marine organisms, and the results of this study offer a new series of specific endpoints for the mechanistic understanding of NP toxicity. PMID:25481784

  18. Nanoparticles for biomedical imaging

    PubMed Central

    Nune, Satish K; Gunda, Padmaja; Thallapally, Praveen K; Lin, Ying-Ying; Forrest, M Laird; Berkland, Cory J

    2011-01-01

    Background Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 – 100 nm in diameter have dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has expanded further the potential of nanoparticles as probes for molecular imaging. Objective To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced nonspecific uptake with increased spatial resolution containing stabilizers conjugated with targeting ligands. Methods This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their application in biomedical imaging. Conclusion Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed. PMID:19743894

  19. Improved non-invasive Optical Coherence Tomography detection of different engineered nanoparticles in food-mimicking matrices.

    PubMed

    Grombe, Ringo; Kirsten, Lars; Mehner, Mirko; Linsinger, Thomas P J; Koch, Edmund

    2016-12-01

    Food industry and regulators require fast and reliable analytical methods for quality control. This especially counts for the detection of engineered nanomaterials (ENMs) in food products. Respective EU regulation is in force, but the development of appropriate methods is still underway. This paper updates the scope of Optical Coherence Tomography (OCT) for ENM/food matrix analysis. A range of nanomaterials and composites - Au@SiO2, Ag, Ag@SiO2 and SiO2 - in a simplified food matrix was investigated. The earlier finding of linear dependencies between concentration in the dispersion and light responses could be reproduced. Being able to analyse non-invasively for a relevant industrial compound such as SiO2, makes OCT an excellent candidate for screening purposes. PMID:27374569

  20. An airborne isothermal haze chamber

    NASA Technical Reports Server (NTRS)

    Hindman, E. E.

    1981-01-01

    Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

  1. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  2. Airborne Remote Sensing of River Flow and Morphology

    NASA Astrophysics Data System (ADS)

    Zuckerman, S.; Anderson, S. P.; McLean, J.; Redford, R.

    2014-12-01

    River morphology, surface slope and flow are some of the fundamental measurements required for surface water monitoring and hydrodynamic research. This paper describes a method of combining bathymetric lidar with space-time processing of mid-wave infrared (MWIR) imagery to simultaneously measure bathymetry, currents and surface slope from an airborne platform. In May 2014, Areté installed a Pushbroom Imaging Lidar for Littoral Surveillance (PILLS) and a FLIR SC8000 MWIR imaging system sampling at 2 Hz in a small twin-engine aircraft. Data was collected over the lower Colorado River between Picacho Park and Parker. PILLS is a compact bathymetric lidar based on streak-tube sensor technology. It provides channel and bank topography and water surface elevation at 1 meter horizontal scales and 25 cm vertical accuracy. Surface currents are derived from the MWIR imagery by tracking surface features using a cross correlation algorithm. This approach enables the retrieval of currents along extended reaches at the forward speed of the aircraft with spatial resolutions down to 5 m with accuracy better than 10 cm/s. The fused airborne data captures current and depth variability on scales of meters over 10's of kilometers collected in just a few minutes. The airborne MWIR current retrievals are combined with the bathymetric lidar data to calculate river discharge which is then compared with real-time streamflow stations. The results highlight the potential for improving our understanding of complex river environments with simultaneous collections from multiple airborne sensors.

  3. NASA Airborne Lidar 1982-1984 Flights

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar 1982-1984 Flights Data from the 1982 NASA Langley Airborne Lidar flights following the eruption of El Chichon ... continuing to January 1984. Transcribed from the following NASA Tech Reports: McCormick, M. P., and M. T. Osborn, Airborne lidar ...

  4. Gas Phase Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Granqvist, Claes; Kish, Laszlo; Marlow, William

    This book deals with gas-phase nanoparticle synthesis and is intended for researchers and research students in nanomaterials science and engineering, condensed matter physics and chemistry, and aerosol science. Gas-phase nanoparticle synthesis is instrumental to nanotechnology - a field in current focus that raises hopes for environmentally benign, resource-lean manufacturing. Nanoparticles can be produced by many physical, chemical, and even biological routes. Gas-phase synthesis is particularly interesting since one can achieve accurate manufacturing control and hence industrial viability.

  5. In vitro response of human osteoblasts to multi-step sol-gel derived bioactive glass nanoparticles for bone tissue engineering.

    PubMed

    Fan, Jian Ping; Kalia, Priya; Di Silvio, Lucy; Huang, Jie

    2014-03-01

    A multi-step sol-gel process was employed to synthesize bioactive glass (BG) nanoparticles. Transmission electron microscopy (TEM) revealed that the BG nanoparticles were spherical and ranged from 30 to 60 nm in diameter. In vitro reactivity of the BG nanoparticles was tested in phosphate buffer saline (PBS), Tris-buffer (TRIS), simulated body fluid (SBF), and Dulbecco's modified Eagle's medium (DMEM), in comparison with similar sized hydroxyapatite (HA) and silicon substituted HA (SiHA) nanoparticles. Bioactivity of the BG nanoparticles was confirmed through Fourier transform infrared spectroscopy (FTIR) analysis. It was found that bone-like apatite was formed after immersion in SBF at 7 days. Solutions containing BG nanoparticles were slightly more alkaline than HA and SiHA, suggesting that a more rapid apatite formation on BG was related to solution-mediated dissolution. Primary human osteoblast (HOB) cell model was used to evaluate biological responses to BG nanoparticles. Lactate dehydrogenase (LDH) cytotoxicity assay showed that HOB cells were not adversely affected by the BG nanoparticles throughout the 7day test period. Interestingly, MTS assay results showed an enhancement in cell proliferation in the presence of BG when compared to HA and SiHA nanoparticles. Particularly, statistically significant (p<0.05) alkaline phosphatase (ALP) activity of HOB cells was found on the culture containing BG nanoparticles, suggesting that the cell differentiation might be promoted by BG. Real-time quantitative PCR analysis (qPCR) further confirmed this finding, as a significantly higher level of RUNX2 gene expression was recorded on the cells cultured in the presence of BG nanoparticles when compared to those with HA and SiHA. PMID:24433905

  6. Saltwater ecotoxicology of Ag, Au, CuO, TiO2, ZnO and C60 engineered nanoparticles: An overview.

    PubMed

    Minetto, D; Volpi Ghirardini, A; Libralato, G

    2016-01-01

    This review paper examined 529 papers reporting experimental nanoecotoxicological original data. Only 126 papers referred to saltwater environments (water column and sediment) including a huge variety of species (n=51), their relative endpoints and engineered nanoparticles (ENPs) (n=38). We tried to provide a synthetic overview of the ecotoxicological effects of ENPs from existing data, refining papers on the basis of cross-cutting selection criteria and supporting a "mind the gap" approach stressing on missing data for hazard and risk assessment. After a codified selection procedure, attention was paid to Ag, Au, CuO, TiO2, ZnO and C60 ENPs, evidencing and comparing the observed nanoecotoxicity range of effect. Several criticisms were evidenced: i) some model organisms are overexploited like microalgae and molluscs compared to annelids, echinoderms and fish; ii) underexploited model organisms: mainly bacteria and fish; iii) exposure scenario variability: high species-specific and ENP scenarios including organism life stage and way of administration/spiking of toxicants; iv) scarce comparability between results due to exposure scenario variability; v) micro- and mesocosms substantially unexplored; vi) mixture effects: few examples are available only for ENPs and traditional pollutants; mixtures of ENPs have not been investigated yet; vii) effects of ions and ENPs: nAg, nCuO and nZnO toxicity aetiology is still a matter of discussion; viii) size and morphology effects of ENPs: scarcely investigated, justified and understood. Toxicity results evidenced that: nAu>nZnO>nAg>nCuO>nTiO2>C60. PMID:27107224

  7. Inventory of Engineered Nanoparticle-Containing Consumer Products Available in the Singapore Retail Market and Likelihood of Release into the Aquatic Environment.

    PubMed

    Zhang, Yuanyuan; Leu, Yu-Rui; Aitken, Robert J; Riediker, Michael

    2015-08-01

    Consumer products containing engineered nanoparticles (ENP) are already entering the marketplace. This leads, inter alia, to questions about the potential for release of ENP into the environment from commercial products. We have inventoried the prevalence of ENP-containing consumer products in the Singapore market by carrying out onsite assessments of products sold in all major chains of retail and cosmetic stores. We have assessed their usage patterns and estimated release factors and emission quantities to obtain a better understanding of the quantities of ENP that are released into which compartments of the aquatic environment in Singapore. Products investigated were assessed for their likelihood to contain ENP based on the declaration of ENP by producers, feature descriptions, and the information on particle size from the literature. Among the 1,432 products investigated, 138 were "confirmed" and 293 were "likely" to contain ENP. Product categories included sunscreens, cosmetics, health and fitness, automotive, food, home and garden, clothing and footwear, and eyeglass/lens coatings. Among the 27 different types of nanomaterials identified, SiO2 was predominant, followed by TiO2 and ZnO, Carbon Black, Ag, and Au. The amounts of ENP released into the aquatic system, which was estimated on the basis of typical product use, ENP concentration in the product, daily use quantity, release factor, and market share, were in the range of several hundred tons per year. As these quantities are likely to increase, it will be important to further study the fate of ENP that reach the aquatic environment in Singapore. PMID:26213957

  8. Cd2+ Toxicity to a Green Alga Chlamydomonas reinhardtii as Influenced by Its Adsorption on TiO2 Engineered Nanoparticles

    PubMed Central

    Yang, Wei-Wan; Miao, Ai-Jun; Yang, Liu-Yan

    2012-01-01

    In the present study, Cd2+ adsorption on polyacrylate-coated TiO2 engineered nanoparticles (TiO2-ENs) and its effect on the bioavailability as well as toxicity of Cd2+ to a green alga Chlamydomonas reinhardtii were investigated. TiO2-ENs could be well dispersed in the experimental medium and their pHpzc is approximately 2. There was a quick adsorption of Cd2+ on TiO2-ENs and a steady state was reached within 30 min. A pseudo-first order kinetics was found for the time-related changes in the amount of Cd2+ complexed with TiO2-ENs. At equilibrium, Cd2+ adsorption followed the Langmuir isotherm with the maximum binding capacity 31.9, 177.1, and 242.2 mg/g when the TiO2-EN concentration was 1, 10, and 100 mg/l, respectively. On the other hand, Cd2+ toxicity was alleviated in the presence of TiO2-ENs. Algal growth was less suppressed in treatments with comparable total Cd2+ concentration but more TiO2-ENs. However, such toxicity difference disappeared and all the data points could be fitted to a single Logistic dose-response curve when cell growth inhibition was plotted against the free Cd2+ concentration. No detectable amount of TiO2-ENs was found to be associated with the algal cells. Therefore, TiO2-ENs could reduce the free Cd2+ concentration in the toxicity media, which further lowered its bioavailability and toxicity to C. reinhardtii. PMID:22403644

  9. Combination wt-p53 and MicroRNA-125b Transfection in a Genetically Engineered Lung Cancer Model Using Dual CD44/EGFR-targeting Nanoparticles.

    PubMed

    Talekar, Meghna; Trivedi, Malav; Shah, Parin; Ouyang, Qijun; Oka, Adwait; Gandham, Srujan; Amiji, Mansoor M

    2016-04-01

    Mutations in KRAS and p53 signaling pathways contribute to loss of responsiveness to current therapies and a decreased survival in lung cancer. In this study, we have investigated the delivery and transfection of wild-type (wt-) p53 and microRNA-125b (miR-125b) expressing plasmid DNA, in SK-LU-1 human lung adenocarcinoma cells as well as in Kras(G12D)/p53(fl/fl) (KP) genetically engineered mouse model of lung cancer. Systemic plasmid DNA delivery with dual CD44/EGFR-targeted hyaluronic acid (HA)-based nanoparticles (NPs) resulted in a 2- to 20-fold increase in wt-p53 and miR-125b gene expression in SK-LU-1 cells. This resulted in enhanced apoptotic activity as seen with increased APAF-1 and caspase-3 gene expression. Similarly, in vivo evaluations in KP mouse model indicated successful CD44/EGFR-targeted delivery. Tumor growth inhibition and apoptotic induction were also observed with (wt-p53+miR125b) combination therapy in KP tumor model. Lastly, J774.A1 murine macrophages co-cultured with transfected SK-LU-1 cells showed a 14- to 35-fold increase in the iNOS-Arg-1 ratio, supportive of previous results demonstrating a role of miR-125b in macrophage repolarization. Overall, these results show tremendous promise of wt-p53 and miR-125b gene therapy using dual CD44/EGFR-targeting HA NP vector for effective treatment of lung cancer. PMID:26686386

  10. Inventory of Engineered Nanoparticle-Containing Consumer Products Available in the Singapore Retail Market and Likelihood of Release into the Aquatic Environment

    PubMed Central

    Zhang, Yuanyuan; Leu, Yu-Rui; Aitken, Robert J.; Riediker, Michael

    2015-01-01

    Consumer products containing engineered nanoparticles (ENP) are already entering the marketplace. This leads, inter alia, to questions about the potential for release of ENP into the environment from commercial products. We have inventoried the prevalence of ENP-containing consumer products in the Singapore market by carrying out onsite assessments of products sold in all major chains of retail and cosmetic stores. We have assessed their usage patterns and estimated release factors and emission quantities to obtain a better understanding of the quantities of ENP that are released into which compartments of the aquatic environment in Singapore. Products investigated were assessed for their likelihood to contain ENP based on the declaration of ENP by producers, feature descriptions, and the information on particle size from the literature. Among the 1,432 products investigated, 138 were “confirmed” and 293 were “likely” to contain ENP. Product categories included sunscreens, cosmetics, health and fitness, automotive, food, home and garden, clothing and footwear, and eyeglass/lens coatings. Among the 27 different types of nanomaterials identified, SiO2 was predominant, followed by TiO2 and ZnO, Carbon Black, Ag, and Au. The amounts of ENP released into the aquatic system, which was estimated on the basis of typical product use, ENP concentration in the product, daily use quantity, release factor, and market share, were in the range of several hundred tons per year. As these quantities are likely to increase, it will be important to further study the fate of ENP that reach the aquatic environment in Singapore. PMID:26213957

  11. Chemical Aspects of Nanoparticle Ecotoxicology.

    PubMed

    Sigg, Laura; Behra, Renata; Groh, Ksenia; Isaacson, Carl; Odzak, Niksa; Piccapietra, Flavio; Röhder, Lena; Schug, Hannah; Yue, Yang; Schirmer, Kristin

    2014-11-01

    Nanoecotoxicology strives to understand the processes and mechanisms by which engineered nanoparticles (ENP) may exert toxic effects on aquatic organisms. Detailed knowledge of the chemical reactions of nanoparticles in the media and of their interactions with organisms is required to understand these effects. The processes of agglomeration of nanoparticles, of dissolution and release of toxic metal ions, and of production of reactive oxygen species (ROS) are considered in this article. Important questions concern the role of uptake of nanoparticles in various organisms, in contrast to uptake of ions released from nanoparticles and to nanoparticle attachment to organism surfaces. These interactions are illustrated for effects of silver nanoparticles (AgNP), cerium oxide (CeO2 NP) and titanium dioxide (TiO2 NP), on aquatic organisms, including algae, biofilms, fish cells and fish embryos. PMID:26508489

  12. Airborne Imagery Collections Barrow 2013

    DOE Data Explorer

    Cherry, Jessica; Crowder, Kerri

    2015-07-20

    The data here are orthomosaics, digital surface models (DSMs), and individual frames captured during low altitude airborne flights in 2013 at the Barrow Environmental Observatory. The orthomosaics, thermal IR mosaics, and DSMs were generated from the individual frames using Structure from Motion techniques.

  13. Airborne fungi--a resurvey

    SciTech Connect

    Meyer, G.H.; Prince, H.E.; Raymer, W.J.

    1983-07-01

    A 15-month survey of airborne fungi at 14 geographical stations was conducted to determine the incidence of different fungal genera. Five of these stations were surveyed 25 years earlier. A comparison between previous studies and present surveys revealed similar organisms at each station with slight shifts in frequency of dominant genera.

  14. Tropospheric and Airborne Emission Spectrometers

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas; Beer, Reinhard

    1996-01-01

    X This paper describes the development of two related instruments, the Tropospheric Emission Spectrometer (TES) and the Airborne Emission Spectrometer (AES). Both instruments are infrared imaging Fourier Transform Spectrometers, used for measuring the state of the lower atmosphere, and in particular the measurement of ozone and ozone sources and sinks.

  15. AARD - Autonomous Airborne Refueling Demonstration

    NASA Technical Reports Server (NTRS)

    Ewers, Dick

    2007-01-01

    This viewgraph document reviews the Autonomous Airborne Refueling Demonstration program, and NASA Dryden's work in the program. The primary goal of the program is to make one fully automatic probe-to-drogue engagement using the AARD system. There are pictures of the aircraft approaching to the docking.

  16. Airborne asbestos in public buildings

    SciTech Connect

    Chesson, J.; Hatfield, J.; Schultz, B.; Dutrow, E.; Blake, J. )

    1990-02-01

    The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.

  17. Time-of-flight measurement techniques for airborne ultrasonic ranging.

    PubMed

    Jackson, Joseph C; Summan, Rahul; Dobie, Gordon I; Whiteley, Simon M; Pierce, S G; Hayward, Gordon

    2013-02-01

    Airborne ultrasonic ranging is used in a variety of different engineering applications for which other positional metrology techniques cannot be used, for example in closed-cell locations, when optical line of sight is limited, and when multipath effects preclude electromagnetic-based wireless systems. Although subject to fundamental physical limitations, e.g., because of the temperature dependence of acoustic velocity in air, these acoustic techniques often provide a cost-effective solution for applications in mobile robotics, structural inspection, and biomedical imaging. In this article, the different techniques and limitations of a range of airborne ultrasonic ranging approaches are reviewed, with an emphasis on the accuracy and repeatability of the measurements. Simple time-domain approaches are compared with their frequency-domain equivalents, and the use of hybrid models and biologically inspired approaches are discussed. PMID:23357908

  18. Identifying Airborne Pathogens in Time to Respond

    SciTech Connect

    Hazi, A

    2006-01-25

    Among the possible terrorist activities that might threaten national security is the release of an airborne pathogen such as anthrax. Because the potential damage to human health could be severe, experts consider 1 minute to be an operationally useful time limit for identifying the pathogen and taking action. Many commercial systems can identify airborne pathogenic microbes, but they take days or, at best, hours to produce results. The Department of Homeland Security (DHS) and other U.S. government agencies are interested in finding a faster approach. To answer this national need, a Livermore team, led by scientist Eric Gard, has developed the bioaerosol mass spectrometry (BAMS) system--the only instrument that can detect and identify spores at low concentrations in less than 1 minute. BAMS can successfully distinguish between two related but different spore species. It can also sort out a single spore from thousands of other particles--biological and nonbiological--with no false positives. The BAMS team won a 2005 R&D 100 Award for developing the system. Livermore's Laboratory Directed Research and Development (LDRD) Program funded the biomedical aspects of the BAMS project, and the Department of Defense's Technical Support Working Group and Defense Advanced Research Project Agency funded the biodefense efforts. Developing a detection system that can analyze small samples so quickly has been challenging. Livermore engineer Vincent Riot, who worked on the BAMS project, explains, ''A typical spore weighs approximately one-trillionth of a gram and is dispersed in the atmosphere, which contains naturally occurring particles that could be present at concentrations thousands of times higher. Previous systems also had difficulty separating benign organisms from those that are pathogenic but very similar, which has resulted in false alarms''.

  19. Engineering of papaya mosaic virus (PapMV) nanoparticles through fusion of the HA11 peptide to several putative surface-exposed sites.

    PubMed

    Rioux, Gervais; Babin, Cindy; Majeau, Nathalie; Leclerc, Denis

    2012-01-01

    Papaya mosaic virus has been shown to be an efficient adjuvant and vaccine platform in the design and improvement of innovative flu vaccines. So far, all fusions based on the PapMV platform have been located at the C-terminus of the PapMV coat protein. Considering that some epitopes might interfere with the self-assembly of PapMV CP when fused at the C-terminus, we evaluated other possible sites of fusion using the influenza HA11 peptide antigen. Two out of the six new fusion sites tested led to the production of recombinant proteins capable of self assembly into PapMV nanoparticles; the two functional sites are located after amino acids 12 and 187. Immunoprecipitation of each of the successful fusions demonstrated that the HA11 epitope was located at the surface of the nanoparticles. The stability and immunogenicity of the PapMV-HA11 nanoparticles were evaluated, and we could show that there is a direct correlation between the stability of the nanoparticles at 37°C (mammalian body temperature) and the ability of the nanoparticles to trigger an efficient immune response directed towards the HA11 epitope. This strong correlation between nanoparticle stability and immunogenicity in animals suggests that the stability of any nanoparticle harbouring the fusion of a new peptide should be an important criterion in the design of a new vaccine. PMID:22363771

  20. Satellite and airborne IR sensor validation by an airborne interferometer

    SciTech Connect

    Gumley, L.E.; Delst, P.F. van; Moeller, C.C.

    1996-11-01

    The validation of in-orbit longwave IR radiances from the GOES-8 Sounder and inflight longwave IR radiances from the MODIS Airborne Simulator (MAS) is described. The reference used is the airborne University of Wisconsin High Resolution Interferometer Sounder (HIS). The calibration of each sensor is described. Data collected during the Ocean Temperature Interferometric Survey (OTIS) experiment in January 1995 is used in the comparison between sensors. Detailed forward calculations of at-sensor radiance are used to account for the difference in GOES-8 and HIS altitude and viewing geometry. MAS radiances and spectrally averaged HIS radiances are compared directly. Differences between GOES-8 and HIS brightness temperatures, and GOES-8 and MAS brightness temperatures, are found to be with 1.0 K for the majority of longwave channels examined. The same validation approach will be used for future sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS). 11 refs., 2 figs., 4 tabs.

  1. Synthesis and Characterization of Protein-Conjugated Silver Nanoparticles/Silver Salt Loaded Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Film for Prevention of Bacterial Infections and Potential Use in Bone Tissue Engineering Applications

    NASA Astrophysics Data System (ADS)

    Bakare, Rotimi Ayotunde

    Failure of orthopedic implants due to bacterial infection has been a major concern in bone tissue engineering. To this end, we have formulated a potential orthopedic implant made of naturally occurring biodegradable polymer, i.e. poly (3-hydroxylbutyrate-co-3-hydroxylvalerate) (PHBV), modified with BSA conjugated silver nanoparticles and or silver chloride. Upon release of Ag NPs and or Ag+ in the implant region, can promote aseptic environment by inhibition of bacteria growth and also support/maintain bone cell adhesion, growth, and proliferation. For formulating nanoparticles loaded PHBV scaffold, we exploit specific interaction between bovine serum albumin (BSA) of BSA capped silver nanoparticles and collagen of collagen immobilized PHBV scaffold. Therefore, the first part of this study dealt with synthesis and characterization of collagen immobilized PHBV film for loading of BSA stabilized silver (Ag/BSA) nanoparticles. Two different approaches were used to immobilize collagen on macroporous PHBV film. First approach uses thermal radical copolymerization with 2-hydroxyethylmethacrylate (HEMA), while the second approach uses aminolysis to functionalize macroporous PHBV film. Using collagen crosslinker, type I collagen was covalently grafted to formulate collagen immobilized PHEMA-g-PHBV and collagen immobilized NH2-PHBV films, respectively. Spectroscopic (FTIR, XPS), physical (SEM), and thermal (TGA) techniques were used to characterize the functionalized PHBV films. The Ag/BSA nanoparticles were then loaded on collagen immobilized PHBV films and untreated PHBV films. The concentration of nanoparticles loaded on PHBV film was determined by atomic absorption spectrometry and fluorescence spectroscopy. The amount of nanoparticles loaded on collagen immobilized PHBV film was found to be significantly greater than that on untreated PHBV film. The amount of Ag/BSA nanoparticles loaded on collagen immobilized PHBV film was found to depend on the concentration of Ag

  2. Large aperture scanning airborne lidar

    NASA Technical Reports Server (NTRS)

    Smith, J.; Bindschadler, R.; Boers, R.; Bufton, J. L.; Clem, D.; Garvin, J.; Melfi, S. H.

    1988-01-01

    A large aperture scanning airborne lidar facility is being developed to provide important new capabilities for airborne lidar sensor systems. The proposed scanning mechanism allows for a large aperture telescope (25 in. diameter) in front of an elliptical flat (25 x 36 in.) turning mirror positioned at a 45 degree angle with respect to the telescope optical axis. The lidar scanning capability will provide opportunities for acquiring new data sets for atmospheric, earth resources, and oceans communities. This completed facility will also make available the opportunity to acquire simulated EOS lidar data on a near global basis. The design and construction of this unique scanning mechanism presents exciting technological challenges of maintaining the turning mirror optical flatness during scanning while exposed to extreme temperatures, ambient pressures, aircraft vibrations, etc.

  3. Magnetic airborne survey - geophysical flight

    NASA Astrophysics Data System (ADS)

    de Barros Camara, Erick; Nei Pereira Guimarães, Suze

    2016-06-01

    This paper provides a technical review process in the area of airborne acquisition of geophysical data, with emphasis for magnetometry. In summary, it addresses the calibration processes of geophysical equipment as well as the aircraft to minimize possible errors in measurements. The corrections used in data processing and filtering are demonstrated with the same results as well as the evolution of these techniques in Brazil and worldwide.

  4. Airborne microorganisms from waste containers.

    PubMed

    Jedlicka, Sabrina S; Stravitz, David M; Lyman, Charles E

    2012-01-01

    In physician's offices and biomedical labs, biological waste is handled every day. This waste is disposed of in waste containers designed for holding red autoclave bags. The containers used in these environments are closed hands-free containers, often with a step pedal. While these containers protect the user from surface-borne microorganisms, the containers may allow airborne microorganisms to escape via the open/close mechanism because of the air current produced upon open/close cycles. In this study, the air current was shown to be sufficient to allow airborne escape of microorganisms held in the container, including Aspergillus niger. However, bacterial cultures, such as Escherichia coli and Lactococcus lactis did not escape. This may be due to the choice of bacterial cultures and the absence of solid waste, such as dust or other particulate matter in the waste containers, that such strains of bacteria could travel on during aerosolization. We compared these results to those obtained using a re-designed receptacle, which mimimizes air currents, and detected no escaping microorganisms. This study highlights one potential source of airborne contamination in labs, hospitals, and other environments that dispose of biological waste. PMID:23047084

  5. Airborne lidar global positioning investigations

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.

    1988-01-01

    The Global Positioning System (GPS) network of satellites shows high promise of revolutionizing methods for conducting surveying, navigation, and positioning. This is especially true in the case of airborne or satellite positioning. A single GPS receiver (suitably adapted for aircraft deployment) can yield positioning accuracies (world-wide) in the order of 30 to 50 m vertically, as well as horizontally. This accuracy is dramatically improved when a second GPS receiver is positioned at a known horizontal and vertical reference. Absolute horizontal and vertical positioning of 1 to 2 m are easily achieved over areas of separation of tens of km. If four common satellites remain in lock in both receivers, then differential phase pseudo-ranges on the GPS L-band carrier can be utilized to achieve accuracies of + or - 10 cm and perhaps as good as + or - 2 cm. The initial proof of concept investigation for airborne positioning using the phase difference between the airborne and stationary GPS receivers was conducted and is examined.

  6. NASA Student Airborne Research Program

    NASA Astrophysics Data System (ADS)

    Schaller, E. L.; Shetter, R. E.

    2012-12-01

    The NASA Student Airborne Research Program (SARP) is a unique summer internship program for advanced undergraduates and early graduate students majoring in the STEM disciplines. SARP participants acquire hands-on research experience in all aspects of an airborne research campaign, including flying onboard an major NASA resource used for studying Earth system processes. In summer 2012, thirty-two participants worked in four interdisciplinary teams to study surface, atmospheric, and oceanographic processes. Participants assisted in the operation of instruments onboard the NASA P-3B aircraft where they sampled and measured atmospheric gases and imaged land and water surfaces in multiple spectral bands. Along with airborne data collection, students participated in taking measurements at field sites. Mission faculty and research mentors helped to guide participants through instrument operation, sample analysis, and data reduction. Over the eight-week program, each student developed an individual research project from the data collected and delivered a conference-style final presentation on his/her results. We will discuss the results and effectiveness of the program from the first four summers and discuss plans for the future.

  7. Airborne particulate matter in spacecraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  8. Survival rate of airborne Mycobacterium bovis.

    PubMed

    Gannon, B W; Hayes, C M; Roe, J M

    2007-04-01

    Despite years of study the principle transmission route of bovine tuberculosis to cattle remains unresolved. The distribution of pathological lesions, which are concentrated in the respiratory system, and the very low dose of Mycobacterium bovis needed to initiate infection from a respiratory tract challenge suggest that the disease is spread by airborne transmission. Critical to the airborne transmission of a pathogenic microorganism is its ability to survive the stresses incurred whilst airborne. This study demonstrates that M. bovis is resistant to the stresses imposed immediately after becoming airborne, 94% surviving the first 10 min after aerosolisation. Once airborne the organism is robust, its viability decreasing with a half-life of approximately 1.5 hours. These findings support the hypothesis that airborne transmission is the principle route of infection for bovine tuberculosis. PMID:17045316

  9. Harnessing nanoparticles for immune modulation

    PubMed Central

    Getts, Daniel R.; Shea, Lonnie D; Miller, Stephen D.; King, Nicholas J.C.

    2015-01-01

    Recent approaches using nanoparticles engineered for immune regulation have yielded promising results in preclinical models of disease. The number of nanoparticle therapies is growing, fueled by innovations in nanotechnology and advances in understanding of the underlying pathogenesis of immune-mediated diseases. In particular, recent mechanistic insight into the ways in which nanoparticles interact with the mononuclear phagocyte system and impact its function during homeostasis and inflammation have highlighted the potential of nanoparticle-based therapies for controlling severe inflammation while concurrently restoring peripheral immune tolerance in autoimmune disease. Here we review recent advances in nanoparticle-based approaches aimed at immune-modulation, and discuss these in the context of concepts in polymeric nanoparticle development, including particle modification, delivery and the factors associated with successful clinical deployment. PMID:26088391

  10. 77 FR 3323 - Airborne Radar Altimeter Equipment (For Air Carrier Aircraft)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-23

    ... [Federal Register Volume 77, Number 14 (Monday, January 23, 2012)] [Notices] [Pages 3323-3324] [FR... Engineering Division, Aircraft Certification Service. [FR Doc. 2012-1243 Filed 1-20-12; 8:45 am] BILLING CODE... cancelling TSO-C67. Please note that TSO-C87, Airborne Low Range Radio Altimeter, is currently used for...

  11. SnxTi1-xO2 solid-solution-nanoparticle embedded mesoporous silica (SBA-15) hybrid as an engineered photocatalyst with enhanced activity.

    PubMed

    Srinivasan, N R; Bandyopadhyaya, Rajdip

    2016-04-12

    Synthesis of hybrids of a porous host-material (with well-dispersed embedded nanoparticles inside the pore), wherein each nanoparticle has precisely controlled properties (size and composition) poses a generic challenge. To this end, a new strategy is proposed to form SnxTi1-xO2 solid-solution-nanoparticles inside the pores of sphere-like mesoporous silica (SBA-15), with different percentages of Sn in the nanoparticle (varying from 5 to 50 at%), for enhanced photocatalysis. X-ray diffraction confirms the formation of solid-solution nanoparticles in the porous silica hybrid, while the location of nanoparticles and elemental composition are identified using electron microscopy. The hybrid with 5 at% of Sn (Sn0.05Ti0.95O2-sphere-like SBA-15) shows the maximum photocatalytic activity for degradation of rhodamine-B dye (first order rate constant for degradation, k = 1.86 h(-1)), compared to both pure TiO2-sphere-like SBA-15 (k = 1.38 h(-1)) or pure SnO2-sphere-like SBA-15 (k = 0.14 h(-1)) or other hybrids in this series. XPS and PL spectra suggest the formation of more oxygen vacancies during the replacement of Ti(4+) with Sn(4+). Electrochemical studies reveal that there is a reduction of charge transfer resistance from 910 kΩ cm(-2) for TiO2-sphere-like SBA-15, to 332 kΩ cm(-2) for Sn0.05Ti0.95O2-sphere-like SBA-15. These results imply that the enhancement in photocatalytic performance is as a result of delay in recombination of charge carriers. Therefore, the approach followed in the present work to form solid-solution nanoparticles inside a porous host without causing pore blockage, would be a promising route towards increasing reaction rates in catalytic applications of hybrid materials. PMID:26765200

  12. NCALM: NSF Supported Center for Airborne Laser Mapping

    NASA Astrophysics Data System (ADS)

    Shrestha, R. L.; Carter, W. E.; Dietrich, W. E.

    2003-12-01

    The National Science Foundation (NSF) recently awarded a grant to create a research center to support the use of airborne laser mapping technology in the scientific community. The NSF supported Center for Airborne Laser Mapping (NCALM) will be operated jointly by the Department of Civil & Coastal Engineering, College of Engineering, University of Florida (UF) and the Department of Earth and Planetary Science, University of California-Berkeley (UCB). NCALM will use the Airborne Laser Swath Mapping (ALSM) system jointly owned by UF and Florida International University (FIU), based at the UF Geosensing Engineering and Mapping (GEM) Research Center. The state-of-the-art laser surveying instrumentation, GPS systems, which are installed in a Cessna 337 Skymaster aircraft, will collect research grade data in areas selected through the competitive NSF grant review process. The ALSM observations will be analyzed both at UF and UCB, and made available to the PI through an archiving and distribution center at UCB-building upon the Berkeley Seismological Laboratory (BSL) Northern California Earthquake Data Center system. The purpose of NCALM is to provide research grade data from ALSM technology to NSF supported research studies in geosciences. The Center will also contribute to software development that will increase the processing speed and data accuracy. This presentation will discuss NCALM operation and the process of submitting proposals to NSF. In addition, it will outline the process to request available NCALM seed project funds to help jump-start small scientific research studies. Funds are also available for travel by academic researchers and students for hands-on knowledge and experience in ALSM technology at UF and UCB.

  13. Data processing of remotely sensed airborne hyperspectral data using the Airborne Processing Library (APL): Geocorrection algorithm descriptions and spatial accuracy assessment

    NASA Astrophysics Data System (ADS)

    Warren, Mark A.; Taylor, Benjamin H.; Grant, Michael G.; Shutler, Jamie D.

    2014-03-01

    Remote sensing airborne hyperspectral data are routinely used for applications including algorithm development for satellite sensors, environmental monitoring and atmospheric studies. Single flight lines of airborne hyperspectral data are often in the region of tens of gigabytes in size. This means that a single aircraft can collect terabytes of remotely sensed hyperspectral data during a single year. Before these data can be used for scientific analyses, they need to be radiometrically calibrated, synchronised with the aircraft's position and attitude and then geocorrected. To enable efficient processing of these large datasets the UK Airborne Research and Survey Facility has recently developed a software suite, the Airborne Processing Library (APL), for processing airborne hyperspectral data acquired from the Specim AISA Eagle and Hawk instruments. The APL toolbox allows users to radiometrically calibrate, geocorrect, reproject and resample airborne data. Each stage of the toolbox outputs data in the common Band Interleaved Lines (BILs) format, which allows its integration with other standard remote sensing software packages. APL was developed to be user-friendly and suitable for use on a workstation PC as well as for the automated processing of the facility; to this end APL can be used under both Windows and Linux environments on a single desktop machine or through a Grid engine. A graphical user interface also exists. In this paper we describe the Airborne Processing Library software, its algorithms and approach. We present example results from using APL with an AISA Eagle sensor and we assess its spatial accuracy using data from multiple flight lines collected during a campaign in 2008 together with in situ surveyed ground control points.

  14. Monitoring of viable airborne SARS virus in ambient air

    NASA Astrophysics Data System (ADS)

    Agranovski, Igor E.; Safatov, Alexander S.; Pyankov, Oleg V.; Sergeev, Alexander N.; Agafonov, Alexander P.; Ignatiev, Georgy M.; Ryabchikova, Elena I.; Borodulin, Alexander I.; Sergeev, Artemii A.; Doerr, Hans W.; Rabenau, Holger F.; Agranovski, Victoria

    Due to recent SARS related issues (Science 300 (5624) 1394; Nature 423 (2003) 240; Science 300 (5627) 1966), the development of reliable airborne virus monitoring procedures has become galvanized by an exceptional sense of urgency and is presently in a high demand (In: Cox, C.S., Wathers, C.M. (Eds.), Bioaerosols Handbook, Lewis Publishers, Boca Raton, FL, 1995, pp. 247-267). Based on engineering control method (Aerosol Science and Technology 31 (1999) 249; 35 (2001) 852), which was previously applied to the removal of particles from gas carriers, a new personal bioaerosol sampler has been developed. Contaminated air is bubbled through porous medium submerged into liquid and subsequently split into multitude of very small bubbles. The particulates are scavenged by these bubbles, and, thus, effectively removed. The current study explores its feasibility for monitoring of viable airborne SARS virus. It was found that the natural decay of such virus in the collection fluid was around 0.75 and 1.76 lg during 2 and 4 h of continuous operation, respectively. Theoretical microbial recovery rates of higher than 55 and 19% were calculated for 1 and 2 h of operation, respectively. Thus, the new sampling method of direct non-violent collection of viable airborne SARS virus into the appropriate liquid environment was found suitable for monitoring of such stress sensitive virus.