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Sample records for airborne engineered nanoparticles

  1. 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.

  2. 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

  3. Respiratory protection against airborne nanoparticles: a review

    NASA Astrophysics Data System (ADS)

    Shaffer, Ronald E.; Rengasamy, Samy

    2009-10-01

    As a precautionary measure, it is often recommended that workers take steps to reduce their exposure to airborne nanoparticles through the use of respiratory protective devices. The purpose of this study was to provide a review and analysis of the research literature and current recommendations on respirators used for protection against nanoparticles. Key research findings were that studies with particles as small as 4 nm have shown that conventional single-fiber filtration theory can be used to describe the filtration performance of respirators and that the most penetrating particle size for respirators equipped with commonly used electrostatic filter media is in the range of 30-100 nm. Future research needs include human laboratory and workplace protection factor studies to measure the respirator total inward leakage of nanoparticles. Industrial hygienists and safety professionals should continue to use traditional respirator selection guidance for workers exposed to nanoparticles.

  4. Towards airborne nanoparticle mass spectrometry with nanomechanical string resonators

    NASA Astrophysics Data System (ADS)

    Schmid, Silvan; Kurek, Maksymilian; Boisen, Anja

    2013-06-01

    Airborne nanoparticles can cause severe harm when inhaled. Therefore, small and cheap portable airborne nanoparticle monitors are highly demanded by authorities and the nanoparticle producing industry. We propose to use nanomechanical resonators to build the next generation cheap and portable airborne nanoparticle sensors. Recently, nanomechanical mass spectrometry was established. One of the biggest challenges of nanomechanical sensors is the low efficiency of diffusion-based sampling. We developed an inertial-based sampling method that enables the efficient sampling of airborne nanoparticles on a nanomechanical sensor operating directly in air. We measured a sampling rate of over 1000 particles per second, for 28 nm silica nanoparticles with a concentration of 380000 #/cm3, collected on a 500 nm wide nanomechanical string resonator. We show that it is possible to reach a saturated sampling regime in which 100% of all nanoparticles are captured that are owing in the projection of the nanostring. We further show that it is possible to detect single airborne nanoparticles by detecting 50 nm Au particles with a 250 nm wide string resonator. Our resonators are currently operating in the first bending mode. Mass spectrometry of airborne nanoparticles requires the simultaneous operation in the first and second mode, which can be implemented in the transduction scheme of the resonator. The presented results lay the cornerstone for the realization of a portable airborne nanoparticle mass spectrometer.

  5. 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.

  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. Monitor for detecting and assessing exposure to airborne nanoparticles

    NASA Astrophysics Data System (ADS)

    Marra, Johan; Voetz, Matthias; Kiesling, Heinz-Jürgen

    2010-01-01

    An important safety aspect of the workplace environment concerns the severity of its air pollution with nanoparticles (NP; <100 nm) and ultrafine particles (UFP; <300 nm). Depending on their size and chemical nature, exposure to these particles through inhalation can be hazardous because of their intrinsic ability to deposit in the deep lung regions and the possibility to subsequently pass into the blood stream. Recommended safety measures in the nanomaterials industry are pragmatic, aiming at exposure minimization in general, and advocating continuous control by monitoring both the workplace air pollution level and the personal exposure to airborne NPs. This article describes the design and operation of the Aerasense NP monitor that enables intelligence gathering in particular with respect to airborne particles in the 10-300 nm size range. The NP monitor provides real time information about their number concentration, average size, and surface areas per unit volume of inhaled air that deposit in the various compartments of the respiratory tract. The monitor's functionality relies on electrical charging of airborne particles and subsequent measurements of the total particle charge concentration under various conditions. Information obtained with the NP monitor in a typical workplace environment has been compared with simultaneously recorded data from a Scanning Mobility Particle Sizer (SMPS) capable of measuring the particle size distribution in the 11-1086 nm size range. When the toxicological properties of the engineered and/or released particles in the workplace are known, personal exposure monitoring allows a risk assessment to be made for a worker during each workday, when the workplace-produced particles can be distinguished from other (ambient) particles.

  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. 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.

  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. Nanoparticle Superlattice Engineering with DNA

    NASA Astrophysics Data System (ADS)

    Macfarlane, Robert J.; Lee, Byeongdu; Jones, Matthew R.; Harris, Nadine; Schatz, George C.; Mirkin, Chad A.

    2011-10-01

    A current limitation in nanoparticle superlattice engineering is that the identities of the particles being assembled often determine the structures that can be synthesized. Therefore, specific crystallographic symmetries or lattice parameters can only be achieved using specific nanoparticles as building blocks (and vice versa). We present six design rules that can be used to deliberately prepare nine distinct colloidal crystal structures, with control over lattice parameters on the 25- to 150-nanometer length scale. These design rules outline a strategy to independently adjust each of the relevant crystallographic parameters, including particle size (5 to 60 nanometers), periodicity, and interparticle distance. As such, this work represents an advance in synthesizing tailorable macroscale architectures comprising nanoscale materials in a predictable fashion.

  12. 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

  13. Non-Engineered Nanoparticles of C60

    PubMed Central

    Deguchi, Shigeru; Mukai, Sada-atsu; Sakaguchi, Hide; Nonomura, Yoshimune

    2013-01-01

    We discovered that rubbing bulk solids of C60 between fingertips generates nanoparticles including the ones smaller than 20 nm. Considering the difficulties usually associated with nanoparticle production by pulverisation, formation of nanoparticles by such a mundane method is unprecedented and noteworthy. We also found that nanoparticles of C60 could be generated from bulk solids incidentally without deliberate engineering of any sort. Our findings imply that there exist highly unusual human exposure routes to nanoparticles of C60, and elucidating formation mechanisms of nanoparticles is crucial in assessing their environmental impacts. PMID:23807024

  14. 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

  15. 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.

  16. Engineered nanoparticles for biomolecular imaging

    NASA Astrophysics Data System (ADS)

    Mahmoudi, Morteza; Serpooshan, Vahid; Laurent, Sophie

    2011-08-01

    In recent years, the production of nanoparticles (NPs) and exploration of their unusual properties have attracted the attention of physicists, chemists, biologists and engineers. Interest in NPs arises from the fact that the mechanical, chemical, electrical, optical, magnetic, electro-optical and magneto-optical properties of these particles are different from their bulk properties and depend on the particle size. There are numerous areas where nanoparticulate systems are of scientific and technological interest, particularly in biomedicine where the emergence of NPs with specific properties (e.g. magnetic and fluorescence) for contrast agents can lead to advancing the understanding of biological processes at the biomolecular level. This review will cover a full description of the physics of various imaging methods, including MRI, optical techniques, X-rays and CT. In addition, the effect of NPs on the improvement of the mentioned non-invasive imaging methods will be discussed together with their advantages and disadvantages. A detailed discussion will also be provided on the recent advances in imaging agents, such as fluorescent dye-doped silica NPs, quantum dots, gold- and engineered polymeric-NPs, superparamagnetic iron oxide NPs (SPIONs), and multimodal NPs (i.e. nanomaterials that are active in both MRI and optical methods), which are employed to overcome many of the limitations of conventional contrast agents (e.g. gadolinium).

  17. Comparison of the behaviour of manufactured and other airborne nanoparticles and the consequences for prioritising research and regulation activities

    NASA Astrophysics Data System (ADS)

    Kumar, Prashant; Fennell, Paul; Robins, Alan

    2010-06-01

    Currently, there are no air quality regulations in force in any part of the world to control number concentrations of airborne atmospheric nanoparticles (ANPs). This is partly due to a lack of reliable information on measurement methods, dispersion characteristics, modelling, health and other environmental impacts. Because of the special characteristics of manufactured (also termed engineered or synthesised) nanomaterials or nanoparticles (MNPs), a substantial increase is forecast for their manufacture and use, despite understanding of safe design and use, and health and environmental implications being in its early stage. This article discusses a number of underlining technical issues by comparing the properties and behaviour of MNPs with anthropogenically produced ANPs. Such a comparison is essential for the judicious treatment of the MNPs in any potential air quality regulatory framework for ANPs.

  18. Pulmonary applications and toxicity of engineered nanoparticles.

    PubMed

    Card, Jeffrey W; Zeldin, Darryl C; Bonner, James C; Nestmann, Earle R

    2008-09-01

    Because of their unique physicochemical properties, engineered nanoparticles have the potential to significantly impact respiratory research and medicine by means of improving imaging capability and drug delivery, among other applications. These same properties, however, present potential safety concerns, and there is accumulating evidence to suggest that nanoparticles may exert adverse effects on pulmonary structure and function. The respiratory system is susceptible to injury resulting from inhalation of gases, aerosols, and particles, and also from systemic delivery of drugs, chemicals, and other compounds to the lungs via direct cardiac output to the pulmonary arteries. As such, it is a prime target for the possible toxic effects of engineered nanoparticles. The purpose of this article is to provide an overview of the potential usefulness of nanoparticles and nanotechnology in respiratory research and medicine and to highlight important issues and recent data pertaining to nanoparticle-related pulmonary toxicity.

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

    NASA Astrophysics Data System (ADS)

    Tsai, Su-Jung (Candace); Ada, Earl; Isaacs, Jacqueline A.; Ellenbecker, Michael J.

    2009-01-01

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

  20. 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

  1. 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...

  2. Engineering of aerosol nanoparticle architectures

    NASA Astrophysics Data System (ADS)

    Jiang, Xingmao

    Aerosol-assisted evaporation-induced self-assembly has been applied to fabricate a wide range of nanoparticle architectures. Ordered core-shell Ce/silica particles are effective for corrosion inhibition of aluminum alloy AA2024-T3. Higher hydrophobicity derived by increasing methyltrimethoxysilane/tetramethoxysilane ratio in the precursor delays the release in water and improves the hydrothermal stability significantly. Long-term corrosion inhibition can be realized using microporous encapsulating materials. A mathematical model has been developed to evaluate the release behavior and obtain the effective diffusion coefficient. To realize a long-term controlled release, low diffusivity and low solubility of the encapsulated cerium compound in the release medium are desirable. To maintain an effective cerium concentration for corrosion protection, a proper formulation of quick-release particles and slow-release particles may be strategically necessary. NaCl is selected as a model salt to investigate the diffusion of ions in nanoporous silica and the formation mechanism for the core-shell structure. Ordered nonporous silica with single crystal NaCl core has also been prepared. Azobenzene ligands have been uniformly anchored to the pore surfaces of the nanoporous silica particles by reacting with 4-(3-triethoxysilylpropylureido) azobenzene (TSUA). The functionalization of pore surfaces by organic groups regulates the hydrophobicity and therefore the release behavior. The modified particles demonstrate a photo controlled release by trans/cis isomerization of azobenzene moieties. Long molecule solvents or polymers can be used as blockers to adjust the release behavior for a long-term controlled release. We have developed a valid simulation method and computer code for the evaporation of ethanol-water-NaCl droplets. Various parameters such as droplet size and surrounding gas temperature and pressure have been examined. The code clearly demonstrates the evolution of

  3. Engineered Gold Nanoparticles and Plant Adaptation Potential

    NASA Astrophysics Data System (ADS)

    Siddiqi, Khwaja Salahuddin; Husen, Azamal

    2016-09-01

    Use of metal nanoparticles in biological system has recently been recognised although little is known about their possible effects on plant growth and development. Nanoparticles accumulation, translocation, growth response and stress modulation in plant system is not well understood. Plants exposed to gold and gold nanoparticles have been demonstrated to exhibit both positive and negative effects. Their growth and yield vary from species to species. Cytoxicity of engineered gold nanoparticles depends on the concentration, particle size and shape. They exhibit increase in vegetative growth and yield of fruit/seed at lower concentration and decrease them at higher concentration. Studies have shown that the gold nanoparticles exposure has improved free radical scavenging potential and antioxidant enzymatic activities and alter micro RNAs expression that regulate different morphological, physiological and metabolic processes in plants. These modulations lead to improved plant growth and yields. Prior to the use of gold nanoparticles, it has been suggested that its cost may be calculated to see if it is economically feasible.

  4. Inorganic nanoparticles engineered to attack bacteria.

    PubMed

    Miller, Kristen P; Wang, Lei; Benicewicz, Brian C; Decho, Alan W

    2015-11-07

    Antibiotics were once the golden bullet to constrain infectious bacteria. However, the rapid and continuing emergence of antibiotic resistance (AR) among infectious microbial pathogens has questioned the future utility of antibiotics. This dilemma has recently fueled the marriage of the disparate fields of nanochemistry and antibiotics. Nanoparticles and other types of nanomaterials have been extensively developed for drug delivery to eukaryotic cells. However, bacteria have very different cellular architectures than eukaryotic cells. This review addresses the chemistry of nanoparticle-based antibiotic carriers, and how their technical capabilities are now being re-engineered to attack, kill, but also non-lethally manipulate the physiologies of bacteria. This review also discusses the surface functionalization of inorganic nanoparticles with small ligand molecules, polymers, and charged moieties to achieve drug loading and controllable release.

  5. 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

  6. 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

  7. Antimicrobial durability of air filters coated with airborne Sophora flavescens nanoparticles.

    PubMed

    Chong, Eui-Seok; Hwang, Gi Byoung; Nho, Chu Won; Kwon, Bo Mi; Lee, Jung Eun; Seo, Sungchul; Bae, Gwi-Nam; Jung, Jae Hee

    2013-02-01

    Airborne biological particles containing viruses, bacteria, and/or fungi can be toxic and cause infections and allergy symptoms. Recently, natural materials such as tea tree oil and Sophora flavescens have shown promising antimicrobial activity when applied as air filter media. Although many of these studies demonstrated excellent antimicrobial efficacy, only a few of them considered external environmental effects such as the surrounding humidity, temperature, and natural degradation of chemicals, all of which can affect the antimicrobial performance of these natural materials. In this study, we investigated the antimicrobial durability of air filters containing airborne nanoparticles from S. flavescens for 5 months. Antimicrobial tests and quantitative chemical analyses were performed every 30 days. Morphological changes in the nanoparticles were also evaluated by scanning electron microscopy. The major antimicrobial compounds remained stable and active for ~90 days at room temperature. After about 90 days, the quantities of major antimicrobial compounds decreased noticeably with a consequent decrease in antimicrobial activity. These results are promising for the implementation of new technologies using natural antimicrobial products and provide useful information regarding the average life expectancy of antimicrobial filters using nanoparticles of S. flavescens.

  8. 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

  9. Assessment of airborne nanoparticles present in industry of aluminum surface treatments.

    PubMed

    Santos, R J; Vieira, M T

    2017-03-01

    Conventional industrial processes are emission sources of unintended nanoparticles which are potentially harmful for the environment and human health. The aim of this study is to assess airborne nanoparticle release from aluminum surface treatment processes in various workplaces. Two direct reading instruments, a scanning mobility particle sizer to measure size distribution and a nanoparticle surface area monitoring to measure the surface area of particles deposited in the human lung, were employed to perform area monitoring. The lacquering paint was the process which released the highest concentration of particles from 10-487 nm (7.06 × 10(6) particles/cm(3)). The lacquering baths process emitted particles of the largest average size (76.9 nm) and the largest surface area deposited in the human lung (167.4 µm(2)/cm(3)). Conversely, the anodizing bath process generated particles of the smallest average size (44.3 nm) and the lowest human lung-deposited surface area (1.2 µm(2)/cm(3)). The total number of particles and the surface area can only be fairly correlated for environments in which the surface area presented higher values. The transmission electron microscopy analysis confirmed the presence of aluminum oxide particles of different dimensions near the LB and AB areas and polymeric-based particles near the LP areas. The findings of this study indicated that lacquering and anodizing surface treatments are indeed responsible for the emission of airborne nanoparticles. It also highlights the importance of control strategies as a means of protecting workers' health and environment.

  10. 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.

  11. *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...

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Optimization of an air–liquid interface exposure system for assessing toxicity of airborne nanoparticles

    PubMed Central

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

    2016-01-01

    Abstract 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

  17. 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.

  18. Characterization of surface hydrophobicity of engineered nanoparticles.

    PubMed

    Xiao, Yao; Wiesner, Mark R

    2012-05-15

    The surface chemistry of nanoparticles, including their hydrophobicity, is a key determinant of their fate, transport and toxicity. Engineered NPs often have surface coatings that control the surface chemistry of NPs and may dominate the effects of the nanoparticle core. Suitable characterization methods for surface hydrophobicity at the nano-scale are needed. Three types of methods, surface adsorption, affinity coefficient and contact angle, were investigated in this study with seven carbon and metal based NPs with and without coatings. The adsorption of hydrophobic molecules, Rose Bengal dye and naphthalene, on NPs was used as one measure of hydrophobicity and was compared with the relative affinity of NPs for octanol or water phases, analogous to the determination of octanol-water partition coefficients for organic molecules. The sessile drop method was adapted for measuring contact angle of a thin film of NPs. Results for these three methods were qualitatively in agreement. Aqueous-nC(60) and tetrahydrofuran-nC(60) were observed to be more hydrophobic than nano-Ag coated with polyvinylpyrrolidone or gum arabic, followed by nano-Ag or nano-Au with citrate-functionalized surfaces. Fullerol was shown to be the least hydrophobic of seven NPs tested. The advantages and limitations of each method were also discussed.

  19. 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

  20. Engineering nanoparticles to silence bacterial communication

    PubMed Central

    Miller, Kristen P.; Wang, Lei; Chen, Yung-Pin; Pellechia, Perry J.; Benicewicz, Brian C.; Decho, Alan W.

    2015-01-01

    The alarming spread of bacterial resistance to traditional antibiotics has warranted the study of alternative antimicrobial agents. Quorum sensing (QS) is a chemical cell-to-cell communication mechanism utilized by bacteria to coordinate group behaviors and establish infections. QS is integral to bacterial survival, and therefore provides a unique target for antimicrobial therapy. In this study, silicon dioxide nanoparticles (Si-NP) were engineered to target the signaling molecules [i.e., acylhomoserine lactones (HSLs)] used for QS in order to halt bacterial communication. Specifically, when Si-NP were surface functionalized with β-cyclodextrin (β-CD), then added to cultures of bacteria (Vibrio fischeri), whose luminous output depends upon HSL-mediated QS, the cell-to-cell communication was dramatically reduced. Reductions in luminescence were further verified by quantitative polymerase chain reaction (qPCR) analyses of luminescence genes. Binding of HSLs to Si-NPs was examined using nuclear magnetic resonance (NMR) spectroscopy. The results indicated that by delivering high concentrations of engineered NPs with associated quenching compounds, the chemical signals were removed from the immediate bacterial environment. In actively-metabolizing cultures, this treatment blocked the ability of bacteria to communicate and regulate QS, effectively silencing and isolating the cells. Si-NPs provide a scaffold and critical stepping-stone for more pointed developments in antimicrobial therapy, especially with regard to QS—a target that will reduce resistance pressures imposed by traditional antibiotics. PMID:25806030

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

    NASA Astrophysics Data System (ADS)

    Göhler, Daniel; Stintz, Michael

    2014-08-01

    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 × 108 and 3 × 1010 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.

  2. 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...

  3. 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.

  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. Engineered polymeric nanoparticles for soil remediation.

    PubMed

    Tungittiplakorn, Warapong; Lion, Leonard W; Cohen, Claude; Kim, Ju-Young

    2004-03-01

    Hydrophobic organic groundwater contaminants, such as polynuclear aromatic hydrocarbons (PAHs), sorb strongly to soils and are difficult to remove. We report here on the synthesis of amphiphilic polyurethane (APU) nanoparticles for use in remediation of soil contaminated with PAHs. The particles are made of polyurethane acrylate anionomer (UAA) or poly(ethylene glycol)-modified urethane acrylate (PMUA) precursor chains that can be emulsified and cross-linked in water. The resulting particles are of colloidal size (17-97 nm as measured by dynamic light scattering). APU particles have the ability to enhance PAH desorption and transport in a manner comparable to that of surfactant micelles, but unlike the surface-active components of micelles, the individual cross-linked precursor chains in APU particles are not free to sorb to the soil surface. Thus, the APU particles are stable independent of their concentration in the aqueous phase. In this paper we show that APU particles can be engineered to achieve desired properties. Our experimental results show that the APU particles can be designed to have hydrophobic interior regions that confer a high affinity for phenanthrene (PHEN) and hydrophilic surfaces that promote particle mobility in soil. The affinity of APU particles for contaminants such as PHEN can be controlled by changing the size of the hydrophobic segment used in the chain synthesis. The mobility of colloidal APU suspensions in soil is controlled by the charge density or the size of the pendent water-soluble chains that reside on the particle surface. Exemplary results are provided illustrating the influence of alternative APU particle formulations with respect to their efficacy for contaminant removal. The ability to control particle properties offers the potential to produce different nanoparticles optimized for varying contaminant types and soil conditions.

  6. 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

  7. Airborne Systems Software Acquisition Engineering Guidebook for Requirements Analysis and Specification.

    DTIC Science & Technology

    1978-09-01

    analysis should be included for each C PCI, e.g., the F-X RDPS. If CPCI’s have not been identified, the airborne software qystem can be treated as a...Fre y Destination mFunction Paragraph SR Symbol NA 0 1 (a5 5 Air-to-Air 3.2. 1Reject O Depresion deg 0 360 0.01 5 Air-to-Air 3.2. 1 Angle Table 4-5. F...making logic. The human engineering requirements should pro- vide enough information about the crew performance so that the crew members can be treated

  8. 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).

  9. Promising iron oxide-based magnetic nanoparticles in biomedical engineering.

    PubMed

    Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Vo, Toi Van; Lee, Beom-Jin

    2012-12-01

    For the past few decades biomedical engineering has imprinted its significant impact on the map of science through its wide applications on many other fields. An important example obviously proving this fact is the versatile application of magnetic nanoparticles in theranostics. Due to preferable properties such as biocompatibility, non-toxicity compared to other metal derivations, iron oxide-based magnetic nanoparticles was chosen to be addressed in this review. Aim of this review is to give the readers a whole working window of these magnetic nanoparticles in the current context of science. Thus, preparation of magnetic iron oxide nanoparticles with the so-far techniques, methods of characterizing the nanoparticles as well as their most recent biomedical applications will be stated.

  10. 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.

  11. Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles

    DTIC Science & Technology

    2007-06-01

    Therapy for Breast Cancer using Targeted Engineered Nanoparticles PRINCIPAL INVESTIGATOR: Naomi J. Halas, Ph.D. CONTRACTING...5a. CONTRACT NUMBER Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles 5b. GRANT NUMBER... nanoparticles and studying the efficiency of nanoparticle attachment to cancer cells. We have demonstrated in mouse tumor models a number of diagnostic

  12. 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.

  13. Engineering of magnetic DNA nanoparticles for tumor-targeted therapy

    NASA Astrophysics Data System (ADS)

    Hosseinkhani, Hossein; Chen, Yi-Ru; He, Wenjie; Hong, Po-Da; Yu, Dah-Shyong; Domb, Abraham J.

    2013-01-01

    This study aims to engineer novel targeted delivery system composed of magnetic DNA nanoparticles to be effective as an efficient targeted gene therapy vehicle for tumor therapy. A polysaccharide, dextran, was chosen as the vector of plasmid DNA-encoded NK4 that acts as an HGF-antagonist and anti-angiogenic regulator for inhibitions of tumor growth, invasion, and metastasis. Spermine (Sm) was chemically introduced to the hydroxyl groups of dextran to obtain dextran-Sm. When Fe2+ solution was added to the mixture of dextran-Sm and a plasmid DNA, homogenous DNA nanoparticles were formed via chemical metal coordination bonding with average size of 230 nm. Characterization of DNA nanoparticles was performed via dynamic light scattering measurement, electrophoretic light scattering measurement, as well as transmission electron microscope. DNA nanoparticles effectively condensed plasmid DNA into nanoparticles and enhanced the stability of DNA, while significantly improved transfection efficiency in vitro and tumor accumulation in vivo. In addition, magnetic DNA nanoparticles exhibited high efficiency in antitumor therapy with regards to tumor growth as well as survival of animals evaluated in the presence of external magnetic field. We conclude that the magnetic properties of these DNA nanoparticles would enhance the tracking of non-viral gene delivery systems when administrated in vivo in a test model. These findings suggest that DNA nanoparticles effectively deliver DNA to tumor and thereby inhibiting tumor growth.

  14. 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

  15. Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles

    DTIC Science & Technology

    2008-06-01

    and shell structures that can be further engineered to have highly controlled and ‘tunable’ properties. These include paramagnetic nanoparticles , which...Therapy for Breast Cancer using Targeted Engineered Nanoparticles PRINCIPAL INVESTIGATOR: Naomi J. Halas, Ph.D. CONTRACTING...5a. CONTRACT NUMBER Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles 5b. GRANT NUMBER

  16. Rationally engineered polymeric cisplatin nanoparticle for improved antitumor efficacy

    PubMed Central

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

    2011-01-01

    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) co-polymer, 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 exhibit an IC50 = 0.77 ± 0.11μM comparable to that of free cisplatin (IC50 = 0.44 ± 0.09 μM). The nanoparticles are internalized into the endolysosomal compartment of cancer cells, and releases cisplatin in a pH-dependent manner. Furthermore, the nanoparticles exhibited 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. PMID:21576779

  17. 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...

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

    PubMed

    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.

  19. 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.

  20. Therapeutic nanoparticles from novel multiblock engineered polyesterurethanes

    NASA Astrophysics Data System (ADS)

    Mattu, C.; Boffito, M.; Sartori, S.; Ranzato, E.; Bernardi, E.; Sassi, M. P.; Di Rienzo, A. M.; Ciardelli, G.

    2012-12-01

    A novel biodegradable material belonging to the class of polyester-urethanes (PURs), based on poly(ɛ-caprolactone) (PCL) blocks, was proposed as matrix-forming material for the preparation of nanoparticles by the solvent displacement method. This method has been widely applied to prepare nanoparticles with reproducible, small size with commercially available polyesters or polyester-polyether copolymers. These carriers often displayed fast and poorly controllable release rates. In response to these problems we proposed the insertion of polyesters into a more complex microstructure, such as that of polyurethanes, characterized by the alternation of hard and soft segments, in order to modulate and control the degradation rate and release profiles. PCL-based PUR (C-BC2000) was synthesized according to a two step synthesis procedure. Commercial PCL and poly( d, l lactide) (PLA) were used as controls; and paclitaxel, a potent anti-neoplastic drug, was encapsulated inside all carriers. Carriers prepared with the new material showed no intrinsic cytotoxicity (A-431 cells), with similar size in the range 211-226 nm and surface charge as the commercial controls. Moreover, C-BC2000 nanoparticles exhibited a slightly faster degradation rate, a much higher encapsulation efficiency (89 % against 24 % and 18 % for PLA and PCL, respectively) and a longer and more controlled release profile. This study highlighted the possibility to successfully employ biodegradable polyurethanes to prepare particles for controlled drug delivery, suggesting further and extensive investigation on the introduction of different PUR formulations in this field.

  1. 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.

  2. Mutagenicity spectra in bacterial strains of airborne and engine exhaust particulate extracts.

    PubMed

    Crebelli, R; Fuselli, S; Conti, G; Conti, L; Carere, A

    1991-12-01

    The mutagenicity spectra of the organic extracts of both airborne particulate matter and diesel and gasoline soot particles were determined using a battery of 9 bacterial strains of different genetic specificity. The assays with crude extracts and with fractionated acidic, neutral and basic components revealed striking differences in the patterns of mutagenic responses produced by each of the complex mixtures investigated. The mutagenicity of air particulate matter was shown to depend mainly on direct-acting acidic and neutral compounds, with a lesser contribution of basic promutagens which required exogenous metabolic activation by liver S9. The assays with a diesel soot extract indicated the prevailing contribution of direct-acting acidic and neutral compounds, and suggested an important role also for nitro derivatives other than nitropyrenes. The gasoline exhaust was characterized by powerful promutagenic compounds, belonging to either the acidic, neutral or basic fractions. The implications of these results are discussed with respect to the contribution of engine exhausts to air pollution, and the possible use of mutagenicity spectra in the analysis of environmental complex mixtures.

  3. 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

  4. 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.

  5. Lattice Engineering via Nanoparticle-DNA Frameworks

    PubMed Central

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

    2017-01-01

    Advances in self-assembly over the last 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 the desired lattice type 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 well-defined 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

  6. 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

  7. Characterizing the effective density and primary particle diameter of airborne nanoparticles produced by spark discharge using mobility and mass measurements (tandem DMA/APM)

    NASA Astrophysics Data System (ADS)

    Charvet, Augustin; Bau, Sébastien; Paez Coy, Natalia Estefania; Bémer, Denis; Thomas, Dominique

    2014-05-01

    Nanoparticles are increasingly used in a wide variety of industries. As yet, their health effects are incompletely characterized. Effective density is among the key characteristics of airborne nanoparticles due to its role in particle deposition in the human respiratory tract and in the conversion of number distributions to mass distributions. Because it cannot be measured directly, different methods have been developed to accede to this parameter. The approach chosen in this study is based on the tandem measurement of airborne nanoparticles electrical mobility and mass (tandem differential mobility analyzer/aerosol particle mass analyzer), which major advantage lies in the absence of hypothesis contrary to the tandem differential mobility analyzer/electrical low pressure impactor (DMA/ELPI). The methodology was first applied to spherical model particles to validate the associated data treatment and protocol. In particular, the influence of APM rotational velocity and airflow rate were investigated with regards to the separation of multiply charged particles and electrometer signal. It emerged from experimental data that a compromise between separation efficiency and detection limit shall be found, depending on the nanoparticles to characterize. Accounting for their wide use in different domains, airborne nanoparticles of constantan®, copper, graphite, iron, silver and titanium, produced by spark discharge appear to be representative of ultrafine particles stemming from different industrial processes. In addition to their effective density, the mass-mobility exponents and primary particle diameters were determined for these particles, and found to agree well with published data.

  8. Assembly, Engineering and Applications of Virus-Based Protein Nanoparticles.

    PubMed

    Mateu, Mauricio G

    Viruses and their protein capsids can be regarded as biologically evolved nanomachines able to perform multiple, complex biological functions through coordinated mechano-chemical actions during the infectious cycle. The advent of nanoscience and nanotechnology has opened up, in the last 10 years or so, a vast number of novel possibilities to exploit engineered viral capsids as protein-based nanoparticles for multiple biomedical, biotechnological or nanotechnological applications. This chapter attempts to provide a broad, updated overview on the self-assembly and engineering of virus capsids, and on applications of virus-based nanoparticles. Different sections provide outlines on: (i) the structure, functions and properties of virus capsids; (ii) general approaches for obtaining assembled virus particles; (iii) basic principles and events related to virus capsid self-assembly; (iv) genetic and chemical strategies for engineering virus particles; (v) some applications of engineered virus particles being developed; and (vi) some examples on the engineering of virus particles to modify their physical properties, in order to improve their suitability for different uses.

  9. A quantitative recipe for engineering protein polymer nanoparticles

    PubMed Central

    Janib, S. Mohd; Pastuszka, M.; Aluri, S.; Folchman-Wagner, Z.; Hsueh, P-Y; Shi, P.; Yi-an; Cui, H.; MacKay, J.A.

    2013-01-01

    Protein polymers can assemble switchable nanostructures with emerging applications as biomaterials and nanomedicines. For example, above a critical micelle temperature (CMT) some elastin-like polypeptide (ELP) diblock copolymers assemble spherical nanoparticles, which may modulate cellular internalization and in vivo biodistribution. To achieve engineering-level control over their properties, this report explores a comprehensive library of ELP monoblock and diblock polymers. For the first time, we report that a surprisingly high core molecular weight is required for stable nanoparticle formation; furthermore, nanoparticle size depends on polymer molecular weight. A mathematical model was developed to characterize four ELP monoblock libraries and to predict the phase behavior of corresponding diblock copolymers. The CMT was almost entirely dependent on the hydrophobic core ELP, while the bulk phase transition temperature (Tt,bulk) depends predominantly on the hydrophilic block. Nanoparticle assembly was accompanied by a conversion in secondary structure of the hydrophobic block from random coil and beta-sheets to type-2 β turns. For the first time, this report enables the rational design of ELP protein polymer nanoparticles with physico-chemico properties that will be suitable for biological applications. PMID:24511327

  10. Aquatic ecotoxicity effect of engineered aminoclay nanoparticles.

    PubMed

    Choi, Moon-Hee; Hwang, Yuhoon; Lee, Hyun Uk; Kim, Bohwa; Lee, Go-Woon; Oh, You-Kwan; Andersen, Henrik R; Lee, Young-Chul; Huh, Yun Suk

    2014-04-01

    In the present study the short term aquatic ecotoxicity of water-solubilized aminoclay nanoparticles (ANPs) of ~51±31 nm average hydrodynamic diameter was characterized. An ecotoxicological evaluation was carried out utilizing standard test organisms of different phyla and trophic levels namely the eukaryotic microalga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the bioluminescent marine bacteria Vibrio fisheri. The effective inhibitory concentration (EC50) with 95% confidence limits for the microalga was 1.29 mg/L (0.72-1.82) for the average growth rate and 0.26 mg/L (0.23-0.31) for the cell yield. The entrapping of algal cells in aggregates of ANP may play a major role in the growth inhibition of algae P. subcapitata. No inhibition was observed for V. fisheri up to 25,000 mg/L (no observed effect concentration; NOEC). For D. magna no immobilization was observed in a limit test with 100 mg/L in 24 h while in 48 h a single animal was immobilized (5% inhibition). Correspondingly, the NOEC of ANP in 24 h was 100 mg/L and the lowest observed effect concentration (LOEC) for 48 h was 100 mg/L. Therefore it can be considered to use ANP as an algal-inhibition agent at concentrations <100 mg/L without affecting or only mildly affecting other organisms including zooplanktons, but further studies on the environmental fate and chronic toxicity of ANP is needed to confirm this.

  11. 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

  12. 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)

  13. 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

  14. Calibration and Data Efforts of the National Ecological Observatory Network (NEON) Airborne Observation Platform during its Engineering Development Phase

    NASA Astrophysics Data System (ADS)

    Adler, J.; Goulden, T.; Kampe, T. U.; Leisso, N.; Musinsky, J.

    2014-12-01

    The National Ecological Observatory Network (NEON) has collected airborne photographic, lidar, and imaging spectrometer data in 5 of 20 unique ecological climate regions (domains) within the United States. As part of its mission to detect and forecast ecological change at continental scales over multiple decades, NEON Airborne Observation Platform (AOP) will aerially survey the entire network of 60 core and re-locatable terrestrial sites annually, each of which are a minimum of 10km-by-10km in extent. The current effort encompasses three years of AOP engineering test flights; in 2017 NEON will transition to full operational status in all 20 domains. To date the total airborne data collected spans 34 Terabytes, and three of the five sampled domain's L1 data are publically available upon request. The large volume of current data, and the expected data collection over the remaining 15 domains, is challenging NEON's data distribution plans, backup capability, and data discovery processes. To provide the public with the highest quality data, calibration and validation efforts of the camera, lidar, and spectrometer L0 data are implemented to produce L1 datasets. Where available, the collected airborne measurements are validated against ground reference points and surfaces and adjusted for instrumentation and atmospheric effects. The imaging spectrometer data is spectrally and radiometrically corrected using NIST-traceable procedures. This presentation highlights three years of flight operation experiences including:1) Lessons learned on payload re-configuration, data extraction, data distribution, permitting requirements, flight planning, and operational procedures2) Lidar validation through control data comparisons collected at the Boulder Municipal Airport (KBDU), the site of NEON's new hangar facility3) Spectrometer calibration efforts, to include both the laboratory and ground observations

  15. Transport and retention of carbon-based engineered and natural nanoparticles through saturated porous media

    NASA Astrophysics Data System (ADS)

    Hedayati, Maryeh; Sharma, Prabhakar; Katyal, Deeksha; Fagerlund, Fritjof

    2016-03-01

    Carbon-based engineered nanoparticles have been widely used due to their small size and unique physical and chemical properties. At the same time, the toxic effects of these nanoparticles on human and fish cells have also been observed; therefore, their release and distribution into the surface and subsurface environment is a subject of concern. The aim of this research is to evaluate and compare the transports and retentions of two types of engineered nanoparticles (multiwalled carbon nanotubes and C60) and the natural carbon nanoparticles collected from a fire accident. Several laboratory experiments were conducted to observe the transport behavior of nanoparticles through a column packed with silica sand. The column experiments were intended to monitor the effect of ionic strength on transport of nanoparticles as a function of their shapes. It was observed that the mobilities of both types of engineered nanoparticles were reduced with the increasing ionic strength from 1.34 to 60 mM. However, at ionic strengths up to 10.89 mM, spherical nanoparticles were more mobile than cylindrical nanoparticles, but the mobility of the cylindrical nanoparticles became significantly higher than spherical nanoparticles at the ionic strength of 60 mM. In comparison with natural fire-born nanoparticles, both types of engineered nanoparticles were much less mobile under the selected experimental condition in this study. Furthermore, inverse modeling was used to calculate parameters such as attachment efficiency, the longitudinal dispersivity, and capacity of the solid phase for the attachment of nanoparticles. The results indicate that the combination of the shape and the solution chemistry of the NPs are responsible for the transport and the retention of nanoparticles in natural environment; however, fire-burned nanoparticles can be highly mobile at the natural groundwater chemistry.

  16. Inhibition effect of engineered silver nanoparticles to bloom forming cyanobacteria

    NASA Astrophysics Data System (ADS)

    Thuy Duong, Thi; Son Le, Thanh; Thu Huong Tran, Thi; Kien Nguyen, Trung; Ho, Cuong Tu; Hien Dao, Trong; Phuong Quynh Le, Thi; Chau Nguyen, Hoai; Dang, Dinh Kim; Thu Huong Le, Thi; Thu Ha, Phuong

    2016-09-01

    Silver nanoparticle (AgNP) has a wide range antibacterial effect and is extensively used in different aspects of medicine, food storage, household products, disinfectants, biomonitoring and environmental remediation etc. In the present study, we examined the growth inhibition effect of engineered silver nanoparticles against bloom forming cyanobacterial M. aeruginosa strain. AgNPs were synthesized by a chemical reduction method at room temperature and UV-Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM) showed that they presented a maximum absorption at 410 nm and size range between 10 and 18 nm. M. aeruginosa cells exposed during 10 d to AgNPs to a range of concentrations from 0 to 1 mg l-1. The changes in cell density and morphology were used to measure the responses of the M. aeruginosa to AgNPs. The control and treatment units had a significant difference in terms of cell density and growth inhibition (p < 0.05). Increasing the concentration of AgNPs, a reduction of the cell growths in all treatment was observed. The inhibition efficiency was reached 98.7% at higher concentration of AgNPs nanoparticles. The term half maximal effective concentration (EC50) based on the cell growth measured by absorbance at 680 nm (A680) was 0.0075 mg l-1. The inhibition efficiency was 98.7% at high concentration of AgNPs (1 mg l-1). Image of SEM and TEM reflected a shrunk and damaged cell wall indicating toxicity of silver nanoparticles toward M. aeruginosa.

  17. A new method for measuring lung deposition efficiency of airborne nanoparticles in a single breath

    PubMed Central

    Jakobsson, Jonas K. F.; Hedlund, Johan; Kumlin, John; Wollmer, Per; Löndahl, Jakob

    2016-01-01

    Assessment of respiratory tract deposition of nanoparticles is a key link to understanding their health impacts. An instrument was developed to measure respiratory tract deposition of nanoparticles in a single breath. Monodisperse nanoparticles are generated, inhaled and sampled from a determined volumetric lung depth after a controlled residence time in the lung. The instrument was characterized for sensitivity to inter-subject variability, particle size (22, 50, 75 and 100 nm) and breath-holding time (3–20 s) in a group of seven healthy subjects. The measured particle recovery had an inter-subject variability 26–50 times larger than the measurement uncertainty and the results for various particle sizes and breath-holding times were in accordance with the theory for Brownian diffusion and values calculated from the Multiple-Path Particle Dosimetry model. The recovery was found to be determined by residence time and particle size, while respiratory flow-rate had minor importance in the studied range 1–10 L/s. The instrument will be used to investigate deposition of nanoparticles in patients with respiratory disease. The fast and precise measurement allows for both diagnostic applications, where the disease may be identified based on particle recovery, and for studies with controlled delivery of aerosol-based nanomedicine to specific regions of the lungs. PMID:27819335

  18. A new method for measuring lung deposition efficiency of airborne nanoparticles in a single breath

    NASA Astrophysics Data System (ADS)

    Jakobsson, Jonas K. F.; Hedlund, Johan; Kumlin, John; Wollmer, Per; Löndahl, Jakob

    2016-11-01

    Assessment of respiratory tract deposition of nanoparticles is a key link to understanding their health impacts. An instrument was developed to measure respiratory tract deposition of nanoparticles in a single breath. Monodisperse nanoparticles are generated, inhaled and sampled from a determined volumetric lung depth after a controlled residence time in the lung. The instrument was characterized for sensitivity to inter-subject variability, particle size (22, 50, 75 and 100 nm) and breath-holding time (3–20 s) in a group of seven healthy subjects. The measured particle recovery had an inter-subject variability 26–50 times larger than the measurement uncertainty and the results for various particle sizes and breath-holding times were in accordance with the theory for Brownian diffusion and values calculated from the Multiple-Path Particle Dosimetry model. The recovery was found to be determined by residence time and particle size, while respiratory flow-rate had minor importance in the studied range 1–10 L/s. The instrument will be used to investigate deposition of nanoparticles in patients with respiratory disease. The fast and precise measurement allows for both diagnostic applications, where the disease may be identified based on particle recovery, and for studies with controlled delivery of aerosol-based nanomedicine to specific regions of the lungs.

  19. 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).

  20. Structural-Engineering Rationales of Gold Nanoparticles for Cancer Theranostics.

    PubMed

    Chen, Wenwen; Zhang, Shaohua; Yu, Yangyang; Zhang, Huisheng; He, Qianjun

    2016-10-01

    Personalized theranostics of cancer is increasingly desired, and can be realized by virtue of multifunctional nanomaterials with possible high performances. Gold nanoparticles (GNPs) are a type of especially promising candidate for cancer theranostics, because their synthesis and modification are facile, their structures and physicochemical properties are flexibly controlled, and they are also biocompatible. Especially, the localized surface plasmon resonance and multivalent coordination effects on the surface endow them with NIR light-triggered photothermal imaging and therapy, controlled drug release, and targeted drug delivery. Although the structure, properties, and theranostic application of GNPs are considerably plentiful, no expert review systematically explains the relationships among their structure, property. and application and induces the engineering rationales of GNPs for cancer theranostics. Hence, there are no clear rules to guide the facile construction of optimal GNP structures aiming at a specific theranostic application. A series of structural-engineering rationales of GNPs for cancer theranostics is proposed through digging out the deep relationships between the structure and properties of GNPs. These rationales will be inspiring for guiding the engineering of specific and advanced GNPs for personalized cancer theranostics.

  1. 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.

  2. 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.

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

    EPA Pesticide Factsheets

    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

  4. 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.

  5. 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.

  6. Engineered silica nanoparticles as additives in lubricant oils

    PubMed Central

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

    2015-01-01

    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. PMID:27877840

  7. Synthesis and optimization of chitosan nanoparticles: Potential applications in nanomedicine and biomedical engineering

    PubMed Central

    Ghadi, Arezou; Mahjoub, Soleiman; Tabandeh, Fatemeh; Talebnia, Farid

    2014-01-01

    Background: Chitosan nanoparticles have become of great interest for nanomedicine, biomedical engineering and development of new therapeutic drug release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity. The aim of the present study was to synthesis and optimize of the chitosan nanoparticles for industrial and biomedical applications. Methods: Fe3O4 was synthesized and optimized as magnetic core nanoparticles and then chitosan covered this magnetic core. The size and morphology of the nano-magnetic chitosan was analyzed by scanning electron microscope (SEM). Topography and size distribution of the nanoparticles were shown with two-dimensional and three-dimensional images of atomic force microscopy (AFM). The nanoparticles were analyzed using transmission electron microscopy (TEM). Results: The chitosan nanoparticles prepared in the experiment exhibited white powder shape. The SEM micrographs of the nano-magnetic chitosan showed that they were approximately uniform spheres. The unmodified chitosan nanoparticles composed of clusters of nanoparticles with sizes ranging from 10 nm to 80 nm. AFM provides a three-dimensional surface profile. The TEM image showed physical aggregation of the chitosan nanoparticles. Conclusion: The results show that a novel chitosan nanoparticle was successfully synthesized and characterized. It seems that this nanoparticle like the other chitosan nano particles has potential applications for nanomedicine, biomedical engineering, industrial and pharmaceutical fields. PMID:25202443

  8. 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.

  9. 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

  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. 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.

  12. Magnetic Nanoparticles: Material Engineering and Emerging Applications in Lithography and Biomedicine

    PubMed Central

    Bao, Yuping; Wen, Tianlong; Samia, Anna Cristina S.; Khandhar, Amit; Krishnan, Kannan M.

    2015-01-01

    We present an interdisciplinary overview of material engineering and emerging applications of iron oxide nanoparticles. We discuss material engineering of nanoparticles in the broadest sense, emphasizing size and shape control, large-area self-assembly, composite/hybrid structures, and surface engineering. This is followed by a discussion of several non-traditional, emerging applications of iron oxide nanoparticles, including nanoparticle lithography, magnetic particle imaging, magnetic guided drug delivery, and positive contrast agents for magnetic resonance imaging. We conclude with a succinct discussion of the pharmacokinetics pathways of iron oxide nanoparticles in the human body –– an important and required practical consideration for any in vivo biomedical application, followed by a brief outlook of the field. PMID:26586919

  13. 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

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

    PubMed

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

    2016-01-01

    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.

  15. 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

  16. Occupational Exposure to Airborne Nanomaterials: An Assessment of Worker Exposure to Aerosolized Metal Oxide Nanoparticles in Semiconductor Wastewater Treatment.

    PubMed

    Brenner, Sara A; Neu-Baker, Nicole M; Caglayan, Cihan; Zurbenko, Igor G

    2015-01-01

    This study characterized potential inhalation exposures of workers to nanometal oxides associated with industrial wastewater treatment processes in a semiconductor research and development facility. Exposure assessment methodology was designed to capture aerosolized engineered nanomaterials associated with the chemical mechanical planarization wafer polishing process that were accessible for worker contact via inhalation in the on-site wastewater treatment facility. The research team conducted air sampling using a combination of filter-based capture methods for particle identification and characterization and real-time direct-reading instruments for semi-quantitation of particle number concentration. Filter-based samples were analyzed using electron microscopy and energy-dispersive x-ray spectroscopy while real-time particle counting data underwent statistical analysis. Sampling conducted over 14 months included 5 discrete sampling series events for 7 job tasks in coordination with on-site employees. The number of filter-based samples captured for analysis by electron microscopy was: 5 from personal breathing zone, 4 from task areas, and 3 from the background. Direct-reading instruments collected data for 5 sample collection periods in the task area and the background, and 2 extended background collection periods. Engineered nanomaterials of interest (Si, Al, Ce) were identified by electron microscopy in filter-based samples from all areas of collection, existing as agglomerates (>500 nm) and nanoparticles (100 nm-500 nm). Particle counts showed an increase in number concentration during and after selected tasks above background. While additional data is needed to support further statistical analysis and determine trends, this initial investigation suggests that nanoparticles used or generated by chemical mechanical planarization become aerosolized and may be accessible for inhalation exposures by workers in wastewater treatment facilities. Additional research is

  17. 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

  18. Transport of engineered silver (Ag) nanoparticles through partially fractured sandstones

    NASA Astrophysics Data System (ADS)

    Neukum, Christoph; Braun, Anika; Azzam, Rafig

    2014-08-01

    Transport behavior and fate of engineered silver nanoparticles (AgNP) in the subsurface is of major interest concerning soil and groundwater protection in order to avoid groundwater contamination of vital resources. Sandstone aquifers are important groundwater resources which are frequently used for public water supply in many regions of the world. The objective of this study is to get a better understanding of AgNP transport behavior in partially fractured sandstones. We executed AgNP transport studies on partially fissured sandstone drilling cores in laboratory experiments. The AgNP concentration and AgNP size in the effluent were analyzed using flow field-flow fractionation mainly. We employed inverse mathematical models on the measured AgNP breakthrough curves to identify and quantify relevant transport processes. Physicochemical filtration, time-dependent blocking due to filling of favorable attachment sites and colloid-facilitated transport were identified as the major processes for AgNP mobility. Physicochemical filtration was found to depend on solute chemistry, mineralogy, pore size distribution and probably on physical and chemical heterogeneity. Compared to AgNP transport in undisturbed sandstone matrix reported in the literature, their mobility in partially fissured sandstone is enhanced probably due to larger void spaces and higher hydraulic conductivity.

  19. Engineering tenofovir loaded chitosan nanoparticles to maximize microbicide mucoadhesion.

    PubMed

    Meng, Jianing; Sturgis, Timothy F; Youan, Bi-Botti C

    2011-09-18

    The objective of this study was to engineer a model anti-HIV microbicide (tenofovir) loaded chitosan based nanoparticles (NPs). Box-Behnken design allowed to assess the influence of formulation variables on the size of NPs and drug encapsulation efficiency (EE%) that were analyzed by dynamic light scattering and UV spectroscopy, respectively. The effect of the NPs on vaginal epithelial cells and Lactobacillus crispatus viability and their mucoadhesion to porcine vaginal tissue were assessed by cytotoxicity assays and fluorimetry, respectively. In the optimal aqueous conditions, the EE% and NPs size were 5.83% and 207.97nm, respectively. With 50% (v/v) ethanol/water as alternative solvent, these two responses increased to 20% and 602 nm, respectively. Unlike small size (182nm) exhibiting burst release, drug release from medium (281 nm) and large (602 nm)-sized NPs fitted the Higuchi (r(2)=0.991) and first-order release (r(2)=0.999) models, respectively. These NPs were not cytotoxic to both the vaginal epithelial cell line and L. crispatus for 48h. When the diameter of the NPs decreased from 900 to 188 nm, the mucoadhesion increased from 6% to 12%. However, the combinatorial effect of EE% and percent mucoadhesion for larger size NPs was the highest. Overall, large-size, microbicide loaded chitosan NPs appeared to be promising nanomedicines for the prevention of HIV transmission.

  20. Engineered nanoparticles induce cell apoptosis: potential for cancer therapy

    PubMed Central

    Ma, Dan-Dan; Yang, Wan-Xi

    2016-01-01

    Engineered nanoparticles (ENPs) have been widely applied in industry, commodities, biology and medicine recently. The potential for many related threats to human health has been highlighted. ENPs with their sizes no larger than 100 nm are able to enter the human body and accumulate in organs such as brain, liver, lung, testes, etc, and cause toxic effects. Many references have studied ENP effects on the cells of different organs with related cell apoptosis noted. Understanding such pathways towards ENP induced apoptosis may aid in the design of effective cancer targeting ENP drugs. Such ENPs can either have a direct effect towards cancer cell apoptosis or can be used as drug delivery agents. Characteristics of ENPs, such as sizes, shape, forms, charges and surface modifications are all seen to play a role in determining their toxicity in target cells. Specific modifications of such characteristics can be applied to reduce ENP bioactivity and thus alleviate unwanted cytotoxicity, without affecting the intended function. This provides an opportunity to design ENPs with minimum toxicity to non-targeted cells. PMID:27056889

  1. 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

  2. Spot the difference: engineered and natural nanoparticles in the environment--release, behavior, and fate.

    PubMed

    Wagner, Stephan; Gondikas, Andreas; Neubauer, Elisabeth; Hofmann, Thilo; von der Kammer, Frank

    2014-11-10

    The production and use of nanoparticles leads to the emission of manufactured or engineered nanoparticles into the environment. Those particles undergo many possible reactions and interactions in the environment they are exposed to. These reactions and the resulting behavior and fate of nanoparticles in the environment have been studied for decades through naturally occurring nanoparticulate (1-100 nm) and colloidal (1-1000 nm) substances. The knowledge gained from these investigations is nowhere near sufficiently complete to create a detailed model of the behavior and fate of engineered nanoparticles in the environment, but is a valuable starting point for the risk assessment of these novel materials. It is the aim of this Review to critically compare naturally observed processes with those found for engineered systems to identify the "nanospecific" properties of manufactured particles and describe critical knowledge gaps relevant for the risk assessment of manufactured nanomaterials in the environment.

  3. Ecotoxicity of engineered nanoparticles to aquatic invertebrates: a brief review and recommendations for future toxicity testing.

    PubMed

    Baun, A; Hartmann, N B; Grieger, K; Kusk, K O

    2008-07-01

    Based on a literature review and an overview of toxic effects of engineered nanoparticles in aquatic invertebrates, this paper proposes a number of recommendations for the developing field of nanoecotoxicology by highlighting the importance of invertebrates as sensitive and relevant test organisms. Results show that there is a pronounced lack of data in this field (less than 20 peer-reviewed papers are published so far), and the most frequently tested engineered nanoparticles in invertebrate tests are C(60), carbon nanotubes, and titanium dioxide. In addition, the majority of the studies have used Daphnia magna as the test organism. To date, the limited number of studies has indicated acute toxicity in the low mg l(-1) range and higher of engineered nanoparticles to aquatic invertebrates, although some indications of chronic toxicity and behavioral changes have also been described at concentrations in the high microg l(-1) range. Nanoparticles have also been found to act as contaminant carriers of co-existing contaminants and this interaction has altered the toxicity of specific chemicals towards D. magna. We recommend that invertebrate testing is used to advance the level of knowledge in nanoecotoxicology through standardized short-term (lethality) tests with invertebrates as a basis for investigating behaviour and bioavailability of engineered nanoparticles in the aquatic environment. Based on this literature review, we further recommend that research is directed towards invertebrate tests employing long-term low exposure with chronic endpoints along with more research in bioaccumulation of engineered nanoparticles in aquatic invertebrates.

  4. 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.

  5. 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.

  6. Characterization of nanoparticles released during construction of photocatalytic pavements using engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Dylla, Heather; Hassan, Marwa M.

    2012-03-01

    With the increasing use of titanium dioxide (TiO2) nanoparticles in self-cleaning materials such as photocatalytic concrete pavements, the release of nanoparticles into the environment is inevitable. Nanoparticle concentration, particle size, surface area, elemental composition, and surface morphology are pertinent to determine the associated risks. In this study, the potential of exposure to synthetic nanoparticles released during construction activities for application of photocatalytic pavements was measured during laboratory-simulated construction activities of photocatalytic mortar overlays and in an actual field application of photocatalytic spray coat. A scanning mobility particle sizer system measured the size distribution of nanoparticles released during laboratory and field activities. Since incidental nanoparticles are released during construction activities, nanoparticle emissions were compared to those from similar activities without nano-TiO2. Nanoparticle counts and size distribution suggest that synthetic nanoparticles are released during application of photocatalytic pavements. In order to identify the nanoparticle source, nanoparticles were also collected for offline characterization using transmission electron microscopy. However, positive identification of synthetic nanoparticles was not possible due to difficulties in obtaining high-resolution images. As a result, further research is recommended to identify nanoparticle composition and sources.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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.

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

    PubMed

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

    2016-04-06

    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.

  16. 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).

  17. 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

  18. Using the Power of Organic Synthesis for Engineering the Interactions of Nanoparticles with Biological Systems.

    PubMed

    Mizuhara, Tsukasa; Moyano, Daniel F; Rotello, Vincent M

    2016-02-01

    The surface properties of nanoparticles (NPs) dictate their interaction with the outside world. The use of precisely designed molecular ligands to control NP surface properties provides an important toolkit for modulating their interaction with biological systems, facilitating their use in biomedicine. In this review we will discuss the application of the atom-by-atom control provided by organic synthesis to the generation of engineered nanoparticles, with emphasis on how the functionalization of NPs with these "small" organic molecules (Mw < 1,000) can be used to engineer NPs for a wide range of applications.

  19. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques.

    PubMed

    Heredia Rivera, Birmania; Gerardo Rodriguez, Martín

    2016-10-01

    Particulate matter accumulated on car engine air-filters (CAFs) was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74-10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt), metallic (mainly Fe), and biological particles (vegetal and animal debris). The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city.

  20. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

    PubMed Central

    Heredia Rivera, Birmania; Gerardo Rodriguez, Martín

    2016-01-01

    Particulate matter accumulated on car engine air-filters (CAFs) was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74–10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt), metallic (mainly Fe), and biological particles (vegetal and animal debris). The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city. PMID:27706087

  1. Modes of interaction between inorganic engineered nanoparticles and biological and abiotic surfaces

    NASA Astrophysics Data System (ADS)

    Schaumann, G. E.; Abraham, P. M.; Dabrunz, A.

    2012-04-01

    Engineered nanoparticles aging and transformation pathways in natural environmental systems are linked with their attachment to surfaces of organisms, plant leaves, biofilms, soil or sediment particles. In this study we investigated attachment of nAg0 and nTiO2 to plant leaves and organic and inorganic model surfaces and daphnia with the objective to understand the physicochemistry behind these interactions as well as potential ecological effects linked with this attachment. Surface-nanoparticle interactions were investigated in well-defined sorption studies and compared to conditions in in ecotoxicological test systems. Model surfaces were chosen to cover a wide range of intermolecular interactions considering van-der Waals interactions as well as proton donor and acceptor interactions. The nanoparticle-surface complexes were analysed with microscopic techniques including optical microscopy, environmental scanning electron microscopy and atomic force microscopy (AFM) as well as with respect to physicochemical interactions. While deposition of nanoparticles in ecotoxicological test systems is often determined by aggregation, and toxicity may be induced by physical effects, sorption of nanoparticle from stable suspensions is controlled by the chemical nature of the model surfaces as well as by the surfaces accessible for the nanoparticles. The current results show that attachment is determined by an intensive interplay between physicochemical nanoparticle-surface interactions, aggregation stability and physical characteristics. This interplay will mutually affect the ecological relevance, including further fate, transport and effects of the nanoparticles in the environment.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. Recent nanoparticle engineering advances in microalgal cultivation and harvesting processes of biodiesel production: a review.

    PubMed

    Lee, Young-Chul; Lee, Kyubock; Oh, You-Kwan

    2015-05-01

    Among the various steps entailed in the production of biodiesel from microalgae, the efficiency and cost-reduction of the cultivation and harvesting steps remain key obstacles to its practical commercialization. Recently, in order to overcome the technical bottlenecks and limitations with regard to both steps, nanoparticle engineering based on particles' unique physico-chemical and mechanical properties has been extensively applied as a powerful analytical and practical tool. These applications include the enhancement of cell growth and/or pigments by light back-scattering, the induction of intracellular lipid accumulation by nutritional competition and/or stress environment, the improvement of cell separation efficiency and processing time from culture broth, the multiple reuse of magnetic nanoparticle flocculant, and integrated one-pot harvesting/cell-disruption. This review presents and discusses the recent nanoparticle-engineering-based developments in the implementation of practical microalgal cultivation and harvesting processes.

  9. 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.

  10. 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...

  11. 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...

  12. Engineering nanofluid electrodes: controlling rheology and electrochemical activity of γ-Fe2O3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Sen, Sujat; Moazzen, Elahe; Aryal, Shankar; Segre, Carlo U.; Timofeeva, Elena V.

    2015-11-01

    Nanofluid electrodes or nanoelectrofuels have significant potential in the field of flow batteries, as at high loadings of solid battery active nanoparticles, their energy density can be orders of magnitude higher than in traditional redox flow battery electrolytes. Nanofluid electrodes must have a manageable viscosity at high particle concentrations (i.e., easily pumpable) and exhibit good electrochemical activity toward charge and discharge reactions. Engineering of such nanofluid electrodes involves development of new and unique approaches to stabilization of nanoparticle suspensions. In this work, we demonstrate a surface modification approach that allows controlling the viscosity of nanofluids at high solid loading, while simultaneously retaining electrochemical activity of the nanoparticles. A scalable single step procedure for the surface grafting of small organic molecules onto iron (III) oxide nanoparticles (γ-Fe2O3, maghemite, 40-150 nm) is demonstrated. Modified iron oxide nanoparticles reported here have 5 wt% of the grafting moiety on the surface, which helps forming stable dispersions with up to 40 wt% of solid loading in alkali aqueous electrolytes with a maximum viscosity of 12 cP at room temperature. The maximum particle concentration achievable in the same electrolyte with pristine nanoparticles is 15 wt%. Electrochemical testing of the pristine and modified nanomaterials in the form of solid-casted electrodes showed a maximum reversible discharge capacity of 280 and 155 mAh/g, respectively, indicating that electrochemical activity of modified nanoparticles is partially suppressed due to the surface grafted moiety.

  13. 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

  14. 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

  15. 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

  16. Plant Mediated Green Synthesis of CuO Nanoparticles: Comparison of Toxicity of Engineered and Plant Mediated CuO Nanoparticles towards Daphnia magna

    PubMed Central

    Saif, Sadia; Tahir, Arifa; Asim, Tayyaba; Chen, Yongsheng

    2016-01-01

    Research on green production methods for metal oxide nanoparticles (NPs) is growing, with the objective to overcome the potential hazards of these chemicals for a safer environment. In this study, facile, ecofriendly synthesis of copper oxide (CuO) nanoparticles was successfully achieved using aqueous extract of Pterospermum acerifolium leaves. P. acerifolium-fabricated CuO nanoparticles were further characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). Plant-mediated CuO nanoparticles were found to be oval shaped and well dispersed in suspension. XPS confirmed the elemental composition of P. acerifolium-mediated copper nanoparticles as comprised purely of copper and oxygen. DLS measurements and ion release profile showed that P. acerifolium-mediated copper nanoparticles were more stable than the engineered CuO NPs. Copper oxide nanoparticles are used in many applications; therefore, their potential toxicity cannot be ignored. A comparative study was performed to investigate the bio-toxic impacts of plant-synthesized and engineered CuO nanoparticles on water flea Daphnia. Experiments were conducted to investigate the 48-h acute toxicity of engineered CuO NPs and plant-synthesized nanoparticles. Lower EC50 value 0.102 ± 0.019 mg/L was observed for engineered CuO NPs, while 0.69 ± 0.226 mg/L was observed for plant-synthesized CuO NPs. Additionally, ion release from CuO nanoparticles and 48-h accumulation of these nano CuOs in daphnids were also calculated. Our findings thus suggest that the contribution of released ions from nanoparticles and particles/ions accumulation in Daphnia needs to be interpreted with care. PMID:28335333

  17. Modelling the Release, Transport and Fate of Engineered Nanoparticles in the Aquatic Environment - A Review.

    PubMed

    Markus, Adriaan A; Parsons, John R; Roex, Erwin W M; de Voogt, Pim; Laane, Remi W P M

    2016-12-28

    Engineered nanoparticles, that is, particles of up to 100 nm in at least one dimension, are used in many consumer products. Their release into the environment as a consequence of their production and use has raised concern about the possible consequences. While they are made of ordinary substances, their size gives them properties that are not manifest in larger particles. It is precisely these properties that make them useful. For instance titanium dioxide nanoparticles are used in transparent sunscreens, because they are large enough to scatter ultraviolet light but too small to scatter visible light.To investigate the occurrence of nanoparticles in the environment we require practical methods to detect their presence and to measure the concentrations as well as adequate modelling techniques. Modelling provides both a complement to the available detection and measurement methods and the means to understand and predict the release, transport and fate of nanoparticles. Many different modelling approaches have been developed, but it is not always clear for what questions regarding nanoparticles in the environment these approaches can be applied. No modelling technique can be used for every possible aspect of the release of nanoparticles into the environment. Hence it is important to understand which technique to apply in what situation. This article provides an overview of the techniques involved with their strengths and weaknesses. Two points need to be stressed here: the modelling of processes like dissolution and the surface activity of nanoparticles, possibly under influence of ultraviolet light, or chemical transformation has so far received relatively little attention. But also the uncertainties surrounding nanoparticles in general-the amount of nanoparticles used in consumer products, what constitutes the appropriate measure of concentration (mass or numbers) and what processes are relevant-should be explicitly considered as part of the modelling.

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

    PubMed

    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

    2015-09-07

    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 Gd(3+). 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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

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

    DOE PAGES

    Mihai, Cosmin; Chrisler, William B.; Xie, Yumei; ...

    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

  5. Engineered PRINT® nanoparticles for controlled delivery of antigens and immunostimulants

    PubMed Central

    Beletskii, Anton; Galloway, Ashley; Rele, Shyam; Stone, Michele; Malinoski, Frank

    2014-01-01

    Particle replication in non-wetting templates (PRINT) is a novel nanoparticle platform that provides compositional flexibility with the ability to specify size and shape in formulating vaccines. The PRINT platform also offers manufacturing and cost advantages over traditional particle technologies. Across multiple antigen and adjuvant formulations, robust antibody and cellular responses have been achieved using PRINT particles in mouse models. Preclinical studies applying PRINT technology in the disease areas of influenza, malaria, and pneumonia are described in this commentary. The proof of principle studies pave the way toward significant cost-effective solutions to global vaccine supply needs. PMID:25424798

  6. Optimization of nanoparticle focusing by coupling thermophoresis and engineered vortex in a microfluidic channel

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Cao, Zhibo; Fraser, John; Oztekin, Alparslan; Cheng, Xuanhong

    2017-01-01

    Enriching nanoparticles in an aqueous solution is commonly practiced for various applications. Despite recent advances in microfluidic technologies, a general method to concentrate nanoparticles in a microfluidic channel in a label free and continuous flow fashion is not yet available, due to strong Brownian motion on the nanoscale. Recent research of thermophoresis indicates that thermophoretic force can overcome the Brownian force to direct nanoparticle movement. Coupling thermophoresis with natural convection on the microscale has been shown to induce significant enrichment of biomolecules in a thermal diffusion column. However, the column operates in a batch process, and the concentrated samples are inconvenient to retrieve. We have recently designed a microfluidic device that combines a helical fluid motion and simple one-dimensional temperature gradient to achieve effective nanoparticle focusing in a continuous flow. The helical convection is introduced by microgrooves patterned on the channel floor, which directly controls the focusing speed and power. Here, COMSOL simulations are conducted to study how the device geometry and flow rate influence transport and subsequent nanoparticle focusing, with a constant temperature gradient. The results demonstrate a complex dependence of nanoparticle accumulation on the microgroove tilting angle, depth, and spacing, as well as channel width and flow rate. Further dimensional analyses reveal that the ratio between particle velocities induced by thermophoretic and fluid inertial forces governs the particle concentration factor, with a maximum concentration at a ratio of approximately one. This simple relationship provides fundamental insights about nanoparticle transport in coupled flow and thermal fields. The study also offers a useful guideline to the design and operation of nanoparticle concentrators based on combining engineered helical fluid motion subject to phoretic fields.

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

    PubMed Central

    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

  8. 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.

  9. Engineering Hydrophobic Organosilica Nanoparticle-Doped Nanofibers for Enhanced and Fouling Resistant Membrane Distillation.

    PubMed

    Hammami, Mohammed Amen; Croissant, Jonas G; Francis, Lijo; Alsaiari, Shahad K; Anjum, Dalaver H; Ghaffour, Noreddine; Khashab, Niveen M

    2017-01-18

    Engineering and scaling-up new materials for better water desalination are imperative to find alternative fresh water sources to meet future demands. Herein, the fabrication of hydrophobic poly(ether imide) composite nanofiber membranes doped with novel ethylene-pentafluorophenylene-based periodic mesoporous organosilica nanoparticles is reported for enhanced and fouling resistant membrane distillation. Novel organosilica nanoparticles were homogeneously incorporated into electrospun nanofiber membranes depicting a proportional increase of hydrophobicity to the particle contents. Direct contact membrane distillation experiments on the organosilica-doped membrane with only 5% doping showed an increase of flux of 140% compared to commercial membranes. The high porosity of organosilica nanoparticles was further utilized to load the eugenol antimicrobial agent which produced a dramatic enhancement of the antibiofouling properties of the membrane of 70% after 24 h.

  10. 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

  11. 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

  12. Ligand engineering of lead chalcogenide nanoparticle solar cells

    NASA Astrophysics Data System (ADS)

    Voros, Marton; Brawand, Nicholas; Galli, Giulia

    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 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.

  13. Harnessing structure-activity relationship to engineer a cisplatin nanoparticle for enhanced antitumor efficacy.

    PubMed

    Paraskar, Abhimanyu S; Soni, Shivani; Chin, Kenneth T; Chaudhuri, Padmaparna; Muto, Katherine W; Berkowitz, Julia; Handlogten, Michael W; Alves, Nathan J; Bilgicer, Basar; Dinulescu, Daniela M; Mashelkar, Raghunath A; Sengupta, Shiladitya

    2010-07-13

    Cisplatin is a first line chemotherapy for most types of cancer. However, its use is dose-limited due to severe nephrotoxicity. Here we report the rational engineering of a novel nanoplatinate inspired by the mechanisms underlying cisplatin bioactivation. We engineered a novel polymer, glucosamine-functionalized polyisobutylene-maleic acid, where platinum (Pt) can be complexed to the monomeric units using a monocarboxylato and an O --> Pt coordinate bond. We show that at a unique platinum to polymer ratio, this complex self-assembles into a nanoparticle, which releases cisplatin in a pH-dependent manner. The nanoparticles are rapidly internalized into the endolysosomal compartment of cancer cells, and exhibit an IC50 (4.25 +/- 0.16 microM) comparable to that of free cisplatin (3.87 +/- 0.37 microM), and superior to carboplatin (14.75 +/- 0.38 microM). The nanoparticles exhibited significantly improved antitumor efficacy in terms of tumor growth delay in breast and lung cancers and tumor regression in a K-ras(LSL/+)/Pten(fl/fl) ovarian cancer model. Furthermore, the nanoparticle treatment resulted in reduced systemic and nephrotoxicity, validated by decreased biodistribution of platinum to the kidney as quantified using inductively coupled plasma spectroscopy. Given the universal need for a better platinate, we anticipate this coupling of nanotechnology and structure-activity relationship to rationally reengineer cisplatin could have a major impact globally in the clinical treatment of cancer.

  14. Engineered magnetic hybrid nanoparticles with enhanced relaxivity for tumor imaging.

    PubMed

    Aryal, Santosh; Key, Jaehong; Stigliano, Cinzia; Ananta, Jeyarama S; Zhong, Meng; Decuzzi, Paolo

    2013-10-01

    Clinically used contrast agents for magnetic resonance imaging (MRI) suffer by the lack of specificity; short circulation time; and insufficient relaxivity. Here, a one-step combinatorial approach is described for the synthesis of magnetic lipid-polymer (hybrid) nanoparticles (MHNPs) encapsulating 5 nm ultra-small super-paramagnetic iron oxide particles (USPIOs) and decorated with Gd(3+) ions. The MHNPs comprise a hydrophobic poly(lactic acid-co-glycolic acid) (PLGA) core, containing up to ~5% USPIOs (w/w), stabilized by lipid and polyethylene glycol (PEG). Gd(3+) ions are directly chelated to the external lipid monolayer. Three different nanoparticle configurations are presented including Gd(3+) chelates only (Gd-MHNPs); USPIOs only (Fe-MHNPs); and the combination thereof (MHNPs). All three MHNPs exhibit a hydrodynamic diameter of about 150 nm. The Gd-MHNPs present a longitudinal relaxivity (r1 = 12.95 ± 0.53 (mM s)(-1)) about four times larger than conventional Gd-based contrast agents (r1 = 3.4 (mM s)(-1)); MHNPs have a transversal relaxivity of r2 = 164.07 ± 7.0 (mM s)(-1), which is three to four times larger than most conventional systems (r2 ~ 50 (mM s)(-1)). In melanoma bearing mice, elemental analysis for Gd shows about 3% of the injected MHNPs accumulating in the tumor and 2% still circulating in the blood, at 24 h post-injection. In a clinical 3T MRI scanner, MHNPs provide significant contrast confirming the observed tumor deposition. This approach can also accommodate the co-loading of hydrophobic therapeutic compounds in the MHNP core, paving the way for theranostic systems.

  15. Potent engineered PLGA nanoparticles by virtue of exceptionally high chemotherapeutic loadings.

    PubMed

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

    2011-02-09

    Herein we report the fabrication of engineered poly(lactic acid-co-glycolic acid) nanoparticles via the PRINT (particle replication in nonwetting 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.

  16. Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications.

    PubMed

    Wu, Wei; Jiang, Chang Zhong; Roy, Vellaisamy A L

    2016-12-01

    Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

  17. Knocking at the door of the unborn child: engineered nanoparticles at the human placental barrier.

    PubMed

    Buerki-Thurnherr, Tina; von Mandach, Ursula; Wick, Peter

    2012-04-05

    Exposure of pregnant women and their unborn children to engineered nanoparticles (NPs) is not yet of major public concern. However, this may soon change in light of the ever-increasing production of NPs and the continuous appearance of novel NP-containing consumer products. However, NPs may not only pose risks to exposed individuals; they offer major potential for the development of novel therapeutic strategies to treat specifically either the mother or the developing foetus. Hence there is every reason to explore the transplacental transfer of engineered NPs in more detail, and to find answers to the vast number of open questions in this fascinating field of research.

  18. 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.

  19. 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

  20. Genetic engineering of bio-nanoparticles for drug delivery: a review.

    PubMed

    Nishimura, Yuya; Ishii, Jun; Ogino, Chiaki; Kondo, Akihiko

    2014-09-01

    Techniques using nanotechnology in the detection and treatment of cancers have made great progress in multidisciplinary fields. The advances in drug delivery systems (DDSs) have been supported mainly by the development of varied nanoparticles (NPs). Although the NPs based on organic and inorganic materials are integral parts in DDSs, bio-nanoparticles containing biopolymer and virus-like particles (VLPs) are attractive biomaterials for DDSs because of their unique features originating in bio-based materials, such as biocompatibility, biodegradability and low immunogenicity. It is notable that these NPs additionally have a great advantage to enable the easy and flexible alteration of their features by genetic engineering approaches. Controlling the sequence and oligomeric process of polypeptide genes permits a variety of choices in type or size of biopolymeric NPs (e.g., elastin-like polypeptide NPs). In contrast, the functional genes are often inserted into the coding sequences for self-assembled proteins to give the VLPs (e.g., hemagglutinating virus of Japan, adeno-associated virus, human immunodeficiency virus-1, simian virus 40 and hepatitis B virus) additional functions. Thus, genetic engineering readily allow alterations of the properties of NPs (e.g., particle shape, size and stability) and grant of new abilities (e.g., cell-specificity and drug loading and release). In this review, we introduce recent advances in bio-nanoparticles from the standpoint of engineering.

  1. 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

  2. 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...

  3. The role of oxidative stress in ambient particulate matter-induced lung diseases and its implications in the toxicity of engineered nanoparticles.

    PubMed

    Li, Ning; Xia, Tian; Nel, Andre E

    2008-05-01

    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 proinflammatory 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 nanoparticles (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 effects 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.

  4. 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.

  5. 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.

  6. Internalisation of engineered nanoparticles into mammalian cells in vitro: influence of cell type and particle properties

    NASA Astrophysics Data System (ADS)

    Busch, Wibke; Bastian, Susanne; Trahorsch, Ulrike; Iwe, Maria; Kühnel, Dana; Meißner, Tobias; Springer, Armin; Gelinsky, Michael; Richter, Volkmar; Ikonomidou, Chrysanthy; Potthoff, Annegret; Lehmann, Irina; Schirmer, Kristin

    2011-01-01

    Cellular internalisation of industrial engineered nanoparticles is undesired and a reason for concern. Here we investigated and compared the ability of seven different mammalian cell cultures in vitro to incorporate six kinds of engineered nanoparticles, focussing on the role of cell type and particle properties in particle uptake. Uptake was examined using light and electron microscopy coupled with energy dispersive X-ray spectroscopy (EDX) for particle element identification. Flow cytometry was applied for semi-quantitative analyses of particle uptake and for exploring the influence on uptake by the phagocytosis inhibitor Cytochalasin D (CytoD). All particles studied were found to enter each kind of cultured cells. Yet, particles were never found within cell nuclei. The presence of the respective particles within the cells was confirmed by EDX. Live-cell imaging revealed the time-dependent process of internalisation of technical nanoparticles, which was exemplified by tungsten carbide particle uptake into the human skin cells, HaCaT. Particles were found to co-localise with lysosomal structures within the cells. The incorporated nanoparticles changed the cellular granularity, as measured by flow cytometry, already after 3 h of exposure in a particle specific manner. By correlating particle properties with flow cytometry data, only the primary particle size was found to be a weakly influential property for particle uptake. CytoD, an inhibitor of actin filaments and therewith of phagocytosis, significantly inhibited the internalisation of particle uptake in only two of the seven investigated cell cultures. Our study, therefore, supports the notion that nanoparticles can enter mammalian cells quickly and easily, irrespective of the phagocytic ability of the cells.

  7. A comparison of chemical structures of soot precursor nanoparticles from liquid fuel combustion in flames and engine

    NASA Astrophysics Data System (ADS)

    Paul, Bireswar; Datta, Amitava; Datta, Aparna; Saha, Abhijit

    2013-04-01

    A comparative study of the chemical structures of soot precursor nanoparticles from the liquid fuel flame and engine exhaust has been performed in this work to establish an association between the particles from both the sources. Different ex-situ measurement techniques have been used to characterize the nanoparticles in samples collected from the laboratory petrol/air and iso-octane/air flames, as well as from a gasoline engine. The TEM images of the sampled material along with the EDS spectra corroborate the existence of carbonaceous nanoparticles. The nature of the UV absorption and fluorescence spectra of the samples from the iso-octane flame environment further confirms the sampled materials to be soot precursor nanoparticles. The DLS size distribution of the particles shows them to be below 10 nm size. FTIR spectrum of the precursor nanoparticles collected form the non-sooting zone of the flame and that of fully grown soot particles show few similarities and dissimilarities among them. The soot particles are found to be much more aromatized as compared to its precursor nanoparticles. The presence of carbonyl functional group (C=O) at around 1,720 cm-1 has been observed in soot precursor nanoparticles, while such oxygenated functional groups are not prominent in soot structure. The absorption (UV and IR) and fluorescence spectra of the carbonaceous material collected from the gasoline engine exhaust show many resemblances with those of soot precursor nanoparticles from flames. These spectroscopic resemblances of the soot precursor nanoparticles from the flame environment and engine exhaust gives the evidence that the in-cylinder combustion is the source of these particles in the engine exhaust.

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

    PubMed

    Meng, Yuan; Su, Fenghua; Chen, Yangzhi

    2016-08-04

    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.

  9. 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.

  10. 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

  11. Design and cellular internalization of genetically engineered polypeptide nanoparticles displaying adenovirus knob domain

    PubMed Central

    Sun, Guoyong; Hsueh, Pang-Yu; Janib, Siti M.; Hamm-Alvarez, Sarah; MacKay, J. Andrew

    2011-01-01

    Hepatocytes and acinar cells exhibit high-efficiency, fiber-dependent internalization of adenovirus; however, viral capsids have unpredictable immunological effects and are challenging to develop into targeted drug carriers. To exploit this internalization pathway and minimize the use of viral proteins, we developed a simple gene product that self assembles nanoparticles decorated with the knob domain of adenovirus serotype 5 fiber protein. The most significant advantages of this platform include: (i) compatibility with genetic engineering; (ii) no bioconjugate chemistry is required to link fusion proteins to the nanoparticle surface; and (iii) it can direct the reversible assembly of large nanoparticles, which are monodisperse, multivalent, and biodegradable. These particles are predominantly composed from diblock copolymers of elastin-like polypeptide (ELP). ELPs have unique phase transition behavior, whereby they self-assemble above a transition temperature that is simple to control. The diblock ELP described contains two motifs with distinct transition temperatures, which assemble nanoparticles at physiological temperatures. Analysis by non-denaturing-PAGE demonstrated that the purified knob-ELP formed trimers or dimers, which is a property of the native knob/fiber protein. Dynamic light scattering indicated that the diblock copolymer, with or without knob, is able to self assemble into nanoparticles ~40 nm in diameter. To examine the functionality of knob-ELP, their uptake was assessed in a hepatocyte cell-line that expresses the receptor for adenovirus serotype 5 fiber and knob, the coxsackievirus and adenovirus receptor (CAR). Both plain ELP and knob-ELP were bound to the outside of hepatocytes; however, the knob-ELP fusion protein exhibits more internalization and localization to lysosomes of hepatocytes. These findings suggest that functional fusion proteins may only minimally influence the assembly temperature and diameter of ELP nanoparticles. These

  12. Size-fractionated characterization and quantification of nanoparticle release rates from a consumer spray product containing engineered nanoparticles

    NASA Astrophysics Data System (ADS)

    Hagendorfer, Harald; Lorenz, Christiane; Kaegi, Ralf; Sinnet, Brian; Gehrig, Robert; Goetz, Natalie V.; Scheringer, Martin; Ludwig, Christian; Ulrich, Andrea

    2010-09-01

    This study describes methods developed for reliable quantification of size- and element-specific release of engineered nanoparticles (ENP) from consumer spray products. A modified glove box setup was designed to allow controlled spray experiments in a particle-minimized environment. Time dependence of the particle size distribution in a size range of 10-500 nm and ENP release rates were studied using a scanning mobility particle sizer (SMPS). In parallel, the aerosol was transferred to a size-calibrated electrostatic TEM sampler. The deposited particles were investigated using electron microscopy techniques in combination with image processing software. This approach enables the chemical and morphological characterization as well as quantification of released nanoparticles from a spray product. The differentiation of solid ENP from the released nano-sized droplets was achieved by applying a thermo-desorbing unit. After optimization, the setup was applied to investigate different spray situations using both pump and gas propellant spray dispensers for a commercially available water-based nano-silver spray. The pump spray situation showed no measurable nanoparticle release, whereas in the case of the gas spray, a significant release was observed. From the results it can be assumed that the homogeneously distributed ENP from the original dispersion grow in size and change morphology during and after the spray process but still exist as nanometer particles of size <100 nm. Furthermore, it seems that the release of ENP correlates with the generated aerosol droplet size distribution produced by the spray vessel type used. This is the first study presenting results concerning the release of ENP from spray products.

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

    PubMed

    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.

  14. 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

  15. Influence of Cu, TiO2 Nanoparticles and Carbon Nano-Horns on Tribological Properties of Engine Oil.

    PubMed

    Zin, V; Agresti, F; Barison, S; Colla, L; Fabrizio, M

    2015-05-01

    The addition of nanoparticles in lubricating oils recently demonstrated to reduce the coefficient of friction and to increase the load-carrying capability of lubricant in coupled surfaces. In this work, different kinds of nanoparticles were tested as additives to engine oil to improve lubrication: copper and titanium oxide nanoparticles and single walled carbon nanohorns (SWCNHs). Two nanoparticle sizes were also tested in case of copper. The tribological properties of these nanofluids were evaluated by Stribeck tests, in order to compare the effect of nanoparticles on friction coefficient and electric contact resistance in different lubrication regimes. Stribeck curves showed that the coefficient of friction was reduced, compared to raw oil, by the action of Cu nanoparticles having 130 nm diameter, leading to a mean decrease of about 17%, and by SWCNHs, with a mean decrease of about 12%. Conversely, no significant changes were detected in presence of Cu nanoparticles having 50 nm diameter or of TiO2. The suspension viscosity and stability were also tested. Wear tests were also carried out, showing a reduction of wear rate up to nearly 50% for Cu nanoparticles (150 nm diameter) and around 30% for SWCNHs. The measurements showed that nanoparticles having size comparable to the mean roughness of coupled surfaces significantly improved the tribological properties of bare oil. An explanation of nanoparticle action is proposed.

  16. Enhanced and tunable optical quantum efficiencies from plasmon bandwidth engineering in bimetallic CoAg nanoparticles

    NASA Astrophysics Data System (ADS)

    Malasi, A.; Taz, H.; Ehrsam, M.; Goodwin, J.; Garcia, H.; Kalyanaraman, R.

    2016-10-01

    Plasmonic nanoparticles are amongst the most effective ways to resonantly couple optical energy into and out of nanometer sized volumes. However, controlling and/or tuning the transfer of this incident energy to the surrounding near and far field is one of the most interesting challenges in this area. Due to the dielectric properties of metallic silver (Ag), its nanoparticles have amongst the highest radiative quantum efficiencies (η), i.e., the ability to radiatively transfer the incident energy to the surrounding. Here we report the discovery that bimetallic nanoparticles of Ag made with immiscible and plasmonically weak Co metal can show comparable and/or even higher η values. The enhancement is a result of the narrowing of the plasmon bandwidth from these bimetal systems. The phenomenological explanation of this effect based on the dipolar approximation points to the reduction in radiative losses within the Ag nanoparticles when in contact with cobalt. This is also supported by a model of coupling between poor and good conductors based on the surface to volume ratio. This study presents a new type of bandwidth engineering, one based on using bimetal nanostructures, to tune and/or enhance the quality factor and quantum efficiency for near and far-field plasmonic applications.

  17. Engineered nanoparticles and organic matter: a review of the state-of-the-art.

    PubMed

    Grillo, Renato; Rosa, André H; Fraceto, Leonardo F

    2015-01-01

    Growth in the development and production of engineered nanoparticles (ENPs) in recent years has increased the potential for interactions of these nanomaterials with aquatic and terrestrial environments. Carefully designed studies are therefore required in order to understand the fate, transport, stability, and toxicity of nanoparticles. Natural organic matter (NOM), such as the humic substances found in water, sediment, and soil, is one of the substances capable of interacting with ENPs. This review presents the findings of studies of the interaction of ENPs and NOM, and the possible effects on nanoparticle stability and the toxicity of these materials in the environment. In addition, ENPs and NOM are utilized for many different purposes, including the removal of metals and organic compounds from effluents, and the development of new electronic sensors and other devices for the detection of active substances. Discussion is therefore provided of some of the ways in which NOM can be used in the production of nanoparticles. Although there has been an increase in the number of studies in this area, further progress is needed to improve understanding of the dynamic interactions between ENPs and NOM.

  18. Health effects of inhaled engineered and incidental nanoparticles.

    PubMed

    Madl, Amy K; Pinkerton, Kent E

    2009-01-01

    Engineered nanoscale materials provide tremendous promise for technological advancements; however, concerns have been raised about whether research of the possible health risks of these nanomaterials is keeping pace with products going to market. Research on nanomaterials, including carbon nanotubes, semiconductor crystals, and other ultrafine particles (i.e., titanium dioxide, quantum dots, iridium) will be examined to illustrate what is currently known or unknown about how particle characteristics (e.g., size, agglomeration, morphology, solubility, surface chemistry) and exposure/dose metrics (e.g., mass, size, surface area) influence the biological fate and toxicity of inhaled nanosized particles. The fact that nanosized particles (1) have a potentially high efficiency for deposition; (2) target both the upper and lower regions of the respiratory tract; (3) are retained in the lungs for a long period of time, and (4) induce more oxidative stress and cause greater inflammatory effects than their fine-sized equivalents suggest a need to study the impact of these particles on the body. Achieving a better understanding of the dynamics at play between particle physicochemistry, transport patterns, and cellular responses in the lungs and other organs will provide a future basis for establishing predictive measures of toxicity or biocompatibility and a framework for assessing potential human health risks.

  19. Potentials of engineered nanoparticles as fertilizers for increasing agronomic productions.

    PubMed

    Liu, Ruiqiang; Lal, Rattan

    2015-05-01

    Development and application of new types of fertilizers using innovative nanotechnology are one of the potentially effective options of significantly enhancing the global agricultural productions needed to meet the future demands of the growing population. Indeed, the review of available literature indicates that some engineered nanomaterials can enhance plant-growth in certain concentration ranges and could be used as nanofertilizers in agriculture to increase agronomic yields of crops and/or minimize environmental pollution. This article summarizes this type of nanomaterials under four categories: macronutrient nanofertilizers, micronutrient nanofertilizers, nutrient-loaded nanofertilizers, and plant-growth-enhancing nanomaterials. Each category is discussed respectively with reference to nanomaterials' chemical composition, particle size, concentrations applied, benefited plant species, plant incubation methods, and plant-growth enhancement aspects and the rates. The importance, research directions, and research requirements of each nanofertilizer category for achieving sustainable agriculture are also specifically examined. Finally, this review suggests that development of N and P macronutrient nanofertilizers is a high research and development priority both for food production and environmental protection.

  20. 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.

  1. Surface engineering of inorganic nanoparticles for imaging and therapy.

    PubMed

    Nam, Jutaek; Won, Nayoun; Bang, Jiwon; Jin, Ho; Park, Joonhyuck; Jung, Sungwook; Jung, Sanghwa; Park, Youngrong; Kim, Sungjee

    2013-05-01

    Many kinds of inorganic nanoparticles (NPs) including semiconductor, metal, metal oxide, and lanthanide-doped NPs have been developed for imaging and therapy applications. Their unique optical, magnetic, and electronic properties can be tailored by controlling the composition, size, shape, and structure. Interaction of such NPs with cells and/or in vivo compartments is critically determined by the surface properties, and sophisticated control over the NP surface is essential to control their fate in biological environments. We review NP surface coating strategies using the categories of small surface ligand, polymer, and lipid. Use of small ligand molecules has the advantage of maintaining the minimal hydrodynamic (HD) size. Polymers can be advantageous in NP anchoring by combining multiple affinity groups. Encapsulation of NPs in polymers, lipids or surfactants can preserve the as-synthesized NPs. NP surface properties and reaction conditions should be carefully considered to obtain a bioconjugate that maintains the physicochemical properties of NP and functionalities of the conjugated biomolecules. We highlight how the surface properties of NPs impact their interactions with cells and in vivo compartments, especially focused on the important surface design parameters such as HD size, surface charge, and targeting. Typically, maximal cellular uptake can take place in the intermediate NP size range of 40-60nm. Clearance of NPs from blood circulation is largely dependent on the degree of uptake by reticuloendothelial system when they are larger than 10nm. When the HD size is below 10nm, NPs show broad distribution over many organs. Reduction of HD size below the limit of renal barrier can achieve fast clearance of NPs. For maximal tumor accumulation, NPs should have long blood circulation time and should be large enough to prevent rapid penetration. NPs are also desired to rapidly clear out from the body after the mission before they cause toxic side effects

  2. 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.

  3. Direct surface engineering of silicon nanoparticles prepared by collinear double-pulse ns laser ablation

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Momeni, A.

    2017-01-01

    In this paper we study the photoluminescence properties of colloidal silicon nanoparticles (Si NPs) in distilled water, with the aim of clarifying the role of surface characteristics on the emission properties. We will show that double-pulse ns laser ablation (DPLA) of a silicon target in water with different inter-pulse delay times of i.e. 5 and 10 ns can result in production of colloidal Si NPs with different PL emission intensities at the visible spectral range of 550-650 nm. The results reveal that DPLA process at the different delay times can induce different oxide related surface characteristics on the Si NPs through the direct surface engineering of the nanoparticles. A detailed analysis of the PL emissions using the stochastic quantum confinement model explained that the different emission behaviors of the colloids are associated with the oxide-related surface states which are contributed as radiative centers in the PL process.

  4. 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.

  5. 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.

  6. Effects of dispersed aggregates of carbon and titanium dioxide engineered nanoparticles on rainbow trout hepatocytes.

    PubMed

    Thomas, Kevin V; Farkas, Julia; Farmen, Eivind; Christian, Paul; Langford, Katherine; Wu, Quinglan; Tollefsen, Knut-Erik

    2011-01-01

    The purpose of this study was to investigate the cytotoxicity and oxidative stress responses of selected engineered carbon and titanium dioxide (TiO2) nanomaterials to rainbow trout (Oncorhynchus mykiss) primary hepatocytes. The engineered nanomaterials tested were C(60) fullerenes, multiwall nanotubes (MWNT), single-wall nanotubes (SWNT) (functionalized and nonfunctionalized), and TiO2 of 5 and 200 nm in size. Characterization of these materials showed that they were typically present in solution as agglomerates. The engineered nanoparticle agglomerates were cytotoxic at nominal concentrations of >3 mg/L, and certain MWNT and SWNT produced significant intracellular reactive oxygen species (ROS) production as well as cytotoxicity. Analyses of the MWNT responsible for ROS production and cytotoxicity for selected transition metals demonstrated the presence of residual cobalt (Co), which was not present in the nonreactive/non-bioactive MWNT. Cobalt alone was not able to induce the observed effects in hepatocyte cells; however, coexposure with MWNT resulted in an increase in cytotoxicity. Data suggest that trace metals often associated with commercial nanotubes are responsible for the observed biological effects. In addition, other mechanisms, such as the proposed facilitated transport (e.g., Trojan horse) type mechanism of uptake, may provoke an increased response compared to aqueous exposures of trace metals in the absence of carbon nanoparticles.

  7. Molecularly imprinted sol-gel nanoparticles for mass-sensitive engine oil degradation sensing.

    PubMed

    Lieberzeit, Peter A; Afzal, Adeel; Glanzing, Gerd; Dickert, Franz L

    2007-09-01

    Titanate sol-gel layers imprinted with midchain carbonic acids have proven highly useful for detecting engine oil degradation processes owing to selective incorporation of oxidised base oil components. Synthesising the material from TiCl(4) in CCl(4) and precipitating with water leads to imprinted TiO(2) nanoparticles with a diameter of 200-300 nm. Replacing the water by a 1 M ammonium hydroxide solution reduces the average particle size to 50-100 nm with retention of the interaction capabilities. Experiments with the latter solution revealed that the 100-nm particles take up substantially more analyte, indicating a size-dependent phenomenon. As the number of interaction sites within each material is the same, this cannot be a consequence of thermodynamics but must be one of accessibility. The sensor characteristic of water-precipitated particles towards engine oil degradation products shows substantially increased sensitivity and dynamic range compared with the corresponding thin films. Coating quartz crystal microbalances with such nanoparticle materials leads to engine oil degradation sensors owing to incorporation of acidic base oil oxidation products. Interaction studies over a large range of layer thicknesses revealed that both the absolute signal and the steepness of the correlation between the sensor signal and the layer height is 2 times higher for the particles.

  8. 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.

  9. 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

  10. 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.

  11. Manipulation metallic nanoparticle at resonant wavelength using engineered azimuthally polarized optical field.

    PubMed

    Rui, Guanghao; Wang, Xiaoyan; Gu, Bing; Zhan, Qiwen; Cui, Yiping

    2016-04-04

    In this work, we proposed a novel strategy to manipulate the behavior of the metallic nanoparticle under the resonant condition by using engineered azimuthally polarized optical field. Through optimizing the spatial phase distribution of the illumination, the optical force can be tailored to support stable optical trapping while avoiding trap destabilization caused by optical overheating effect simultaneously. Besides, the resonant particle can be stably trapped at predefined location in 3 dimensional space, or revolves around the beam axis with characteristics that can be holistically controlled in terms of both trajectory and rotation direction. The technique demonstrated in this work may open up new avenues for optical manipulation.

  12. Nanoparticle emissions from a heavy-duty engine running on alternative diesel fuels.

    PubMed

    Heikkilä, Juha; Virtanen, Annele; Rönkkö, Topi; Keskinen, Jorma; Aakko-Saksa, Päivi; Murtonen, Timo

    2009-12-15

    We have studied the effect of three different fuels (fossil diesel fuel (EN590); rapeseed methyl ester (RME); and synthetic gas-to-liquid (GTL)) on heavy-duty diesel engine emissions. Our main focus was on nanoparticle emissions of the engine. Our results show that the particle emissions from a modern diesel engine run with EN590, GTL, or RME consisted of two partly nonvolatile modes that were clearly separated in particle size. The concentration and geometric mean diameter of nonvolatile nucleation mode cores measured with RME were substantially greater than with the other fuels. The soot particle concentration and soot particle size were lowest with RME. With EN590 and GTL, a similar engine load dependence of the nonvolatile nucleation mode particle size and concentration imply a similar formation mechanism of the particles. For RME, the nonvolatile core particle size was larger and the concentration dependence on engine load was clearly different from that of EN590 and GTL. This indicates that the formation mechanism of the core particles is different for RME. This can be explained by differences in the fuel characteristics.

  13. Engineering of lipid-coated PLGA nanoparticles with a tunable payload of diagnostically active nanocrystals for medical imaging†

    PubMed Central

    Mieszawska, Aneta J.; Gianella, Anita; Cormode, David P.; Zhao, Yiming; Meijerink, Andries; Langer, Robert; Farokhzad, Omid C.; Fayad, Zahi A.; Mulder, Willem J. M.

    2013-01-01

    Polylactic-co-glycolic acid (PLGA) based nanoparticles are biocompatible and biodegradable and therefore have been extensively investigated as therapeutic carriers. Here, we engineered diagnostically active PLGA nanoparticles that incorporate high payloads of nanocrystals into their core for tunable bioimaging features. We accomplished this through esterification reactions of PLGA to generate polymers modified with nanocrystals. The PLGA nanoparticles formed from modified PLGA polymers that were functionalized with either gold nanocrystals or quantum dots exhibited favorable features for computed tomography and optical imaging, respectively. PMID:22555311

  14. 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.

  15. Aqueous Aggregation Behavior of Engineered Superparamagnetic Iron Oxide Nanoparticles: Effects of Oxidative Surface Aging.

    PubMed

    Li, Wenlu; Lee, Seung Soo; Mittelman, Anjuliee M; Liu, Di; Wu, Jiewei; Hinton, Carl H; Abriola, Linda M; Pennell, Kurt D; Fortner, John D

    2016-12-06

    For successful aqueous-based applications, it is necessary to fundamentally understand and control nanoparticle dispersivity and stability over a range of dynamic conditions, including variable ionic strengths/types, redox chemistries, and surface ligand reactivity/degradation states (i.e., surface aging). Here, we quantitatively describe the behavior of artificially aged, oleic acid (OA) bilayer coated iron oxide nanoparticles (IONPs) under different scenarios. Hydrogen peroxide (H2O2), used here as a model oxidant under both dark and light ultraviolet (UVA) conditions, was employed to "age" materials, to varying degrees, without increasing ionic strength. Short-term stability experiments indicate that OA-IONPs, while stable in the dark, are effectively destabilized when exposed to UVA/H2O2/•OH based oxidation processes. Compared to bicarbonate, phosphate (1.0 mM) has a net stabilizing effect on OA-IONPs under oxidative conditions, which can be attributed to (surface-based) functional adsorption. Corresponding aggregation kinetics in the presence of monovalent (Na(+)) and divalent cations (Ca(2+)) show that attachment efficiencies (α) are strongly dependent on the cation concentrations/types and degree of surface aging. Taken together, our findings directly highlight the need to understand the critical role of particle surface transformation(s), via oxidative aging, among other routes, with regard to the ultimate stability and environmental fate of surface functionalized engineered nanoparticles.

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

    PubMed

    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

    2012-12-10

    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 poly(ethylene 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.

  17. 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

  18. Influence of real-world engine load conditions on nanoparticle emissions from a DPF and SCR equipped heavy-duty diesel engine.

    PubMed

    Thiruvengadam, Arvind; Besch, Marc C; Carder, Daniel K; Oshinuga, Adewale; Gautam, Mridul

    2012-02-07

    The experiments aimed at investigating the effect of real-world engine load conditions on nanoparticle emissions from a Diesel Particulate Filter and Selective Catalytic Reduction after-treatment system (DPF-SCR) equipped heavy-duty diesel engine. The results showed the emission of nucleation mode particles in the size range of 6-15 nm at conditions with high exhaust temperatures. A direct result of higher exhaust temperatures (over 380 °C) contributing to higher concentration of nucleation mode nanoparticles is presented in this study. The action of an SCR catalyst with urea injection was found to increase the particle number count by over an order of magnitude in comparison to DPF out particle concentrations. Engine operations resulting in exhaust temperatures below 380 °C did not contribute to significant nucleation mode nanoparticle concentrations. The study further suggests the fact that SCR-equipped engines operating within the Not-To-Exceed (NTE) zone over a critical exhaust temperature and under favorable ambient dilution conditions could contribute to high nanoparticle concentrations to the environment. Also, some of the high temperature modes resulted in DPF out accumulation mode (between 50 and 200 nm) particle concentrations an order of magnitude greater than typical background PM concentrations. This leads to the conclusion that sustained NTE operation could trigger high temperature passive regeneration which in turn would result in lower filtration efficiencies of the DPF that further contributes to the increased solid fraction of the PM number count.

  19. 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

  20. 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.

  1. 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

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

    PubMed

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

    2015-12-10

    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.

  3. Effects of Engineered Cerium Oxide Nanoparticles on Bacterial Growth and Viability▿†

    PubMed Central

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

    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, due to a lack of standard methods for assessing such interactions. 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. The growth and viability of the Gram-negative species Escherichia coli and Shewanella oneidensis, a metal-reducing bacterium, and the Gram-positive species Bacillus subtilis were examined relative to cerium oxide particle size, growth media, pH, and dosage. A hydrothermal synthesis approach 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 from MIC and CFU measurements, disk diffusion tests, and live/dead assays. For E. coli and B. subtilis, clear strain- and size-dependent inhibition was observed, whereas S. oneidensis appeared to be unaffected by the particles. Transmission electron microscopy along with microarray-based transcriptional profiling was used to understand the response mechanism of the bacteria. Use of multiple analytical approaches adds confidence to toxicity assessments, while the use of different bacterial systems highlights the potential wide-ranging effects of nanomaterial interactions in the environment. PMID:20952651

  4. 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

  5. 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.

  6. Airborne Particles.

    ERIC Educational Resources Information Center

    Ojala, Carl F.; Ojala, Eric J.

    1987-01-01

    Describes an activity in which students collect airborne particles using a common vacuum cleaner. Suggests ways for the students to convert their data into information related to air pollution and human health. Urges consideration of weather patterns when analyzing the results of the investigation. (TW)

  7. Airborne Imagery

    NASA Technical Reports Server (NTRS)

    1983-01-01

    ATM (Airborne Thematic Mapper) was developed for NSTL (National Space Technology Companies) by Daedalus Company. It offers expanded capabilities for timely, accurate and cost effective identification of areas with prospecting potential. A related system is TIMS, Thermal Infrared Multispectral Scanner. Originating from Landsat 4, it is also used for agricultural studies, etc.

  8. 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

    2015-08-05

    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.

  9. Assessing the Immunosafety of Engineered Nanoparticles with a Novel in Vitro Model Based on Human Primary Monocytes.

    PubMed

    Li, Yang; Italiani, Paola; Casals, Eudald; Valkenborg, Dirk; Mertens, Inge; Baggerman, Geert; Nelissen, Inge; Puntes, Victor F; Boraschi, Diana

    2016-10-13

    The possibility that nanomaterials could perturb the normal course of an inflammatory response is a key issue when assessing nanoimmunosafety. The alteration of the normal progress of an inflammatory response may have pathological consequences, since inflammation is a major defensive mechanism and its efficiency maintains the body's health. The immunosafety of engineered nanoparticles at nontoxic concentrations was investigated with the use of a human primary monocyte-based in vitro system, which reproduces in a simplified fashion the full course of the physiological inflammatory response, from initiation and development to resolution. The kinetics of expression and production of inflammatory and anti-inflammatory cytokines and the proteomic profiles were used for describing the inflammatory defensive response. We assessed the ability of gold and silver nanoparticles to trigger inflammation and to interfere with the course of an ongoing defensive reaction. While neither nanoparticle type was able to directly activate monocytes, silver nanoparticles could exacerbate the inflammatory response of monocytes but did not interfere with the resolution of the inflammatory reaction. These findings support the use of human primary monocyte-based in vitro assays for realistically investigating the effects of engineered nanoparticles on human innate immune responses, in order to predict the immunological risk of nanomaterials and implement safe nanoparticle-based applications.

  10. 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

  11. 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…

  12. 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...

  13. 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

  14. 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.

  15. Airborne engineered nanomaterials in the workplace-a review of release and worker exposure during nanomaterial production and handling processes.

    PubMed

    Ding, Yaobo; Kuhlbusch, Thomas A J; Van Tongeren, Martie; Jiménez, Araceli Sánchez; Tuinman, Ilse; Chen, Rui; Alvarez, Iñigo Larraza; Mikolajczyk, Urszula; Nickel, Carmen; Meyer, Jessica; Kaminski, Heinz; Wohlleben, Wendel; Stahlmecke, Burkhard; Clavaguera, Simon; Riediker, Michael

    2017-01-15

    For exposure and risk assessment in occupational settings involving engineered nanomaterials (ENMs), it is important to understand the mechanisms of release and how they are influenced by the ENM, the matrix material, and process characteristics. This review summarizes studies providing ENM release information in occupational settings, during different industrial activities and using various nanomaterials. It also assesses the contextual information - such as the amounts of materials handled, protective measures, and measurement strategies - to understand which release scenarios can result in exposure. High-energy processes such as synthesis, spraying, and machining were associated with the release of large numbers of predominantly small-sized particles. Low-energy processes, including laboratory handling, cleaning, and industrial bagging activities, usually resulted in slight or moderate releases of relatively large agglomerates. The present analysis suggests that process-based release potential can be ranked, thus helping to prioritize release assessments, which is useful for tiered exposure assessment approaches and for guiding the implementation of workplace safety strategies. The contextual information provided in the literature was often insufficient to directly link release to exposure. The studies that did allow an analysis suggested that significant worker exposure might mainly occur when engineering safeguards and personal protection strategies were not carried out as recommended.

  16. Assessing the impact of engineered nanoparticles on wound healing using a novel in vitro bioassay

    PubMed Central

    Zhou, Enhua H; Watson, Christa; Pizzo, Richard; Cohen, Joel; Dang, Quynh; de Barros, Pedro Macul Ferreira; Park, Chan Young; Chen, Cheng; Brain, Joseph D; Butler, James P; Ruberti, Jeffrey W; Fredberg, Jeffrey J; Demokritout, Philip

    2015-01-01

    Aim As engineered nanoparticles (ENPs) increasingly enter consumer products, humans become increasingly exposed. The first line of defense against ENPs is the epithelium, the integrity of which can be compromised by wounds induced by trauma, infection, or surgery, but the implications of ENPs on wound healing are poorly understood. Materials & methods Herein, we developed an in vitro assay to assess the impact of ENPs on the wound healing of cells from human cornea. Results & discussion We show that industrially relevant ENPs impeded wound healing and cellular migration in a manner dependent on the composition, dose and size of the ENPs as well as cell type. CuO and ZnO ENPs impeded both viability and wound healing for both fibroblasts and epithelial cells. Carboxylated polystyrene ENPs retarded wound healing of corneal fibroblasts without affecting viability. Conclusion Our results highlight the impact of ENPs on cellular wound healing and provide useful tools for studying the physiological impact of ENPs. PMID:24823434

  17. Microplastic Exposure Assessment in Aquatic Environments: Learning from Similarities and Differences to Engineered Nanoparticles.

    PubMed

    Hüffer, Thorsten; Praetorius, Antonia; Wagner, Stephan; von der Kammer, Frank; Hofmann, Thilo

    2017-03-07

    Microplastics (MPs) have been identified as contaminants of emerging concern in aquatic environments and research into their behavior and fate has been sharply increasing in recent years. Nevertheless, significant gaps remain in our understanding of several crucial aspects of MP exposure and risk assessment, including the quantification of emissions, dominant fate processes, types of analytical tools required for characterization and monitoring, and adequate laboratory protocols for analysis and hazard testing. This Feature aims at identifying transferrable knowledge and experience from engineered nanoparticle (ENP) exposure assessment. This is achieved by comparing ENP and MPs based on their similarities as particulate contaminants, whereas critically discussing specific differences. We also highlight the most pressing research priorities to support an efficient development of tools and methods for MPs environmental risk assessment.

  18. Engineered Human Ferritin Nanoparticles for Direct Delivery of Tumor Antigens to Lymph Node and Cancer Immunotherapy

    PubMed Central

    Lee, Bo-Ram; Ko, Ho Kyung; Ryu, Ju Hee; Ahn, Keum Young; Lee, Young-Ho; Oh, Se Jin; Na, Jin Hee; Kim, Tae Woo; Byun, Youngro; Kwon, Ick Chan; Kim, Kwangmeyung; Lee, Jeewon

    2016-01-01

    Efficient delivery of tumor-specific antigens (TSAs) to lymph nodes (LNs) is essential to eliciting robust immune response for cancer immunotherapy but still remains unsolved. Herein, we evaluated the direct LN-targeting performance of four different protein nanoparticles with different size, shape, and origin [Escherichia coli DNA binding protein (DPS), Thermoplasma acidophilum proteasome (PTS), hepatitis B virus capsid (HBVC), and human ferritin heavy chain (hFTN)] in live mice, using an optical fluorescence imaging system. Based on the imaging results, hFTN that shows rapid LN targeting and prolonged retention in LNs was chosen as a carrier of the model TSA [red fluorescence protein (RFP)], and the flexible surface architecture of hFTN was engineered to densely present RFPs on the hFTN surface through genetic modification of subunit protein of hFTN. The RFP-modified hFTN rapidly targeted LNs, sufficiently exposed RFPs to LN immune cells during prolonged period of retention in LNs, induced strong RFP-specific cytotoxic CD8+ T cell response, and notably inhibited RFP-expressing melanoma tumor growth in live mice. This suggests that the strategy using protein nanoparticles as both TSA-carrying scaffold and anti-cancer vaccine holds promise for clinically effective immunotherapy of cancer. PMID:27725782

  19. Manufacturing Techniques and Surface Engineering of Polymer Based Nanoparticles for Targeted Drug Delivery to Cancer

    PubMed Central

    Wang, Yichao; Li, Puwang; Truong-Dinh Tran, Thao; Zhang, Juan; Kong, Lingxue

    2016-01-01

    The evolution of polymer based nanoparticles as a drug delivery carrier via pharmaceutical nano/microencapsulation has greatly promoted the development of nano- and micro-medicine in the past few decades. Poly(lactide-co-glycolide) (PLGA) and chitosan, which are biodegradable and biocompatible polymers, have been approved by both the Food & Drug Administration (FDA) and European Medicine Agency (EMA), making them ideal biomaterials that can be advanced from laboratory development to clinical oral and parental administrations. PLGA and chitosan encapsulated nanoparticles (NPs) have successfully been developed as new oral drug delivery systems with demonstrated high efficacy. This review aims to provide a comprehensive overview of the fabrication of PLGA and chitosan particulate systems using nano/microencapsulation methods, the current progress and the future outlooks of the nanoparticulate drug delivery systems. Especially, we focus on the formulations and nano/micro-encapsulation techniques using top-down techniques. It also addresses how the different phases including the organic and aqueous ones in the emulsion system interact with each other and subsequently influence the properties of the drug delivery system. Besides, surface modification strategies which can effectively engineer intrinsic physicochemical properties are summarised. Finally, future perspectives and potential directions of PLGA and chitosan nano/microencapsulated drug systems are outlined. PMID:28344283

  20. 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

  1. 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.

  2. Fate assessment of engineered nanoparticles in solids dominated media - Current insights and the way forward.

    PubMed

    Peijnenburg, W; Praetorius, A; Scott-Fordsmand, J; Cornelis, G

    2016-11-01

    Exposure assessment of engineered nanoparticles (ENPs) in soil and sediment is severely hampered by a lack of understanding of the underlying processes and of the impact of matrix constituents on the fate of ENPs in natural systems, including porewater properties like pH, ionic strength, and presence of naturally occurring (nano)particles. Additional issues such as lack of proper methods for in-situ assessment of ENP speciation, ENP ageing, and agglomeration state, hinder proper exposure assessment. Let alone that the lack does not allow for development of predictive methods for endpoints like transformation and agglomeration potential. This paper discusses current approaches for fate assessment of ENPs in solids dominated media and addresses the most prominent knowledge gaps and how these may be addressed. It is concluded that the key issue to be dealt with, are the attachment and deposition processes that are characteristic for ENPs as opposed to equilibrium-driven partitioning processes of non-particulate organic and inorganic contaminants.

  3. 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.

  4. Exploring the development of a decision support system (DSS) to prioritize engineered nanoparticles for risk assessment

    NASA Astrophysics Data System (ADS)

    Marvin, Hans J. P.; Bouwmeester, Hans; Bakker, Martine; Kroese, E. Dinant; van de Meent, Dik; Bourgeois, Francois; Lokers, Rob; van der Ham, Henk; Verhelst, Lieke

    2013-08-01

    Engineered nanoparticles (ENPs) have gained huge commercial interest because of their unique and size-related physicochemical properties. The diversity and complexity of ENPs is increasing with the introduction of next generation nanoparticles. The current approaches are not able to assess the safety of all types and applications of ENPs. Therefore, we are developing a decision support system (DSS) that helps to identify those ENPs and applications that should get priority in the risk assessment. This DSS smartly uses existing knowledge in publicly available databases. With the aid of vocabularies, knowledge rules and logic reasoning new knowledge will be derived. In this paper, the procedure for a DSS is described. Since this system is open by design, others can re-use and extend the DSS content, and newly developed DSS tools can be easily accommodated, which will make the DSS more effective over the years. Data of newly emerging studies will be used for the validation of the DSS. The results will benefit regulating authorities and scientists focussing on the development of inherently safe ENPs.

  5. Nano-composite scaffolds for bone tissue engineering containing silver nanoparticles: preparation, characterization and biological properties.

    PubMed

    Marsich, Eleonora; Bellomo, Francesca; Turco, Gianluca; Travan, Andrea; Donati, Ivan; Paoletti, Sergio

    2013-07-01

    In this study nano-composite scaffolds to be used as bone grafts have been endowed with antibacterial properties owing to the presence of silver nanoparticles. The alginate/hydroxyapatite composite scaffolds were prepared by internal gelation followed by a freeze-drying procedure to obtain a porous structure. The nanoparticles were prepared in presence of a lactose modified-chitosan and this colloidal solution was adsorbed on the scaffolds by exploiting electrostatic interactions. The adsorption and release of the silver from the composite scaffold was measured by ICP-AES and spectrofluorimetry measurements. Micro-computed tomography analysis of the scaffolds showed a homogeneous porous structure with average pore sizes of 341.5 μm and porosity of 80 %. In vitro biological tests (MTS and killing kinetics assays) demonstrated that silver does not affect the ability of the scaffolds to promote osteoblasts proliferation and that at the same time it exerts a strong bactericidal effect against both Gram+ and Gram- bacterial strains. Overall, the combined results indicate that these biocompatible antimicrobial scaffolds possess ideal characteristics for tissue engineering applications.

  6. 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

  7. 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

  8. Deutsches SOFIA Institut (DSI) at the SOFIA Science Center: engineering and scientific contributions to the airborne observatory

    NASA Astrophysics Data System (ADS)

    Wolf, Jürgen; Colditz, Sebastian; Lachenmann, Michael; Pfüller, Enrico; Schindler, Karsten; Wiedemann, Manuel; Zinnecker, Hans; Krabbe, Alfred

    2016-09-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5-meter infrared telescope built into a Boeing 747SP. In 2014 SOFIA reached its "Full Operational Capability" milestone and nowadays takes off about three times a week to observe the infrared sky from altitudes above most of the atmosphere's water vapor content. Despite reaching this major milestone, efforts to improve the observatory's performance are continuing in many areas. The team of the Deutsches SOFIA Institut, DSI (German SOFIA Institute) at the SOFIA Science Center in Moffett Field, CA works in several engineering areas to improve the observatory's performance and its efficiency. DSI supports the allocation process of SOFIA's observation time for guest observers, provides and supports two facility science instruments and conducts an observing program of stellar occultations by small objects of the solar system. This paper summarizes results and ongoing work on a spare secondary mirror made of aluminum, the new and improved Focal Plane Imager (FPI+) that has become a facility science instrument, the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS), new cameras and optics for the Fine Field and Wide Field Imagers (FFI+ and WFI+), real-time astrometric solution of star field images, ground support equipment and astronomical observations.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. Analytical characterization of engineered ZnO nanoparticles relevant for hazard assessment

    NASA Astrophysics Data System (ADS)

    Bragaru, Adina; Kusko, Mihaela; Vasile, Eugeniu; Simion, Monica; Danila, Mihai; Ignat, Teodora; Mihalache, Iuliana; Pascu, Razvan; Craciunoiu, Florea

    2013-01-01

    The optoelectronic properties of zinc oxide nanoparticles (ZnO-NPs) have determined development of novel applications in catalysis, paints, wave filters, UV detectors, transparent conductive films, solar cells, or sunscreens. While the immediate advantages of using nano-ZnO in glass panel coatings and filter screens for lamps, as protecting products against bleaching, have been demonstrated, the potential environmental effect of the engineered NPs and the associated products was not fully estimated; this issue being of utmost importance, as these materials will be supplied to the market in quantities of tons per year, equating to thousands of square meters. In this study, ZnO-NPs with commercial name Zincox™ have been subjected to a comprehensive characterization, relevant for hazard assessment, using complementary physico-chemical methods. Therefore, the morphological investigations have been corroborated with XRD pattern analyses and UV-Vis absorption related properties resulting an excellent correlation between the geometrical sizes revealed by microscopy (8.0-9.0 nm), and, respectively, the crystallite size (8.2-9.5 nm) and optical size (7.8 nm) calculated from the last two techniques' data. Furthermore, the hydrodynamic diameter of ZnO-NPs and stability of aqueous dispersions with different concentration of nanoparticles have been analyzed as function of significant solution parameters, like concentration, pH and solution ionic strength. The results suggest that solution chemistry exerts a strong influence on ZnO dissolution stability, the complete set of analyses providing useful information toward better control of dosage during biotoxicological tests.

  14. Thermogelling chitosan-collagen-bioactive glass nanoparticle hybrids as potential injectable systems for tissue engineering.

    PubMed

    Moreira, Cheisy D F; Carvalho, Sandhra M; Mansur, Herman S; Pereira, Marivalda M

    2016-01-01

    Recently, stimuli-responsive nanocomposite-derived hydrogels have gained prominence in tissue engineering because they can be applied as injectable scaffolds in bone and cartilage repair. Due to the great potential of these systems, this study aimed to synthesize and characterize novel thermosensitive chitosan-based composites, chemically modified with collagen and reinforced by bioactive glass nanoparticles (BG) on the development of injectable nanohybrids for regenerative medicine applications. Thus, the composite hydrogels were extensively characterized by structural, morphological, rheological, and biological testing. The composites showed thermosensitive response with the gelation temperature at approximately 37 °C, which is compatible with the human body temperature. In addition, scanning electron microscopy (SEM) analysis indicated that the chitosan hydrogels exhibited 3D-porous structures, and the incorporation of collagen in the system caused increase on the average pore size. Fourier transform infrared spectroscopy (FTIR) analysis indicated the main functional groups of each component of the composite system and their chemical interactions forming the scaffold. Moreover, rheological measurements were employed to assess the viscoelastic behavior of the hydrogels as a function of the temperature. The results demonstrated that the addition of collagen and bioactive glass increases the mechanical properties after the gelation process. The addition of 2 wt.% of BG nanoparticles caused an increase of approximately 39% on stiffness compared to pure chitosan and the addition of 30 wt.% collagen caused a further increase on the stiffness by 95%. The cytotoxicity and cell viability of the hydrogels were assessed by MTT and LIVE/DEAD® assays, where the results demonstrated no toxic effect of the composites on the human osteosarcoma cell culture (SAOS) and kidney cells line of human embryo (HEK 293 T). Hence, it can be stated that innovative composites were

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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

    2016-04-06

    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).

  2. Impact of Engineered Zinc Oxide Nanoparticles on the Individual Performance of Mytilus galloprovincialis

    PubMed Central

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

    2013-01-01

    The increased use of engineered nanoparticles (ENPs) in consumer products raises the concern of environmental release and subsequent impacts in natural communities. We tested for physiological and demographic impacts of ZnO, a prevalent metal oxide ENP, on the mussel Mytilus galloprovincialis. We exposed mussels of two size classes, <4.5 and ≥4.5 cm shell length, to 0.1–2 mg l−1 ZnO ENPs in seawater for 12 wk, and measured the effect on mussel respiration, accumulation of Zn, growth, and survival. After 12 wk of exposure to ZnO ENPs, respiration rates of mussels increased with ZnO concentration. Mussels had up to three fold more Zn in tissues than control groups after 12 wk of exposure, but patterns of Zn accumulation varied with mussel size and Zn concentrations. Small mussels accumulated Zn 10 times faster than large mussels at 0.5 mg l−1, while large mussels accumulated Zn four times faster than small mussels at 2 mg l−1. Mussels exposed to 2 mg l−1 ZnO grew 40% less than mussels in our control group for both size classes. Survival significantly decreased only in groups exposed to the highest ZnO concentration (2 mg l−1) and was lower for small mussels than large. Our results indicate that ZnO ENPs are toxic to mussels but at levels unlikely to be reached in natural marine waters. PMID:23613941

  3. Impact of engineered zinc oxide nanoparticles on the individual performance of Mytilus galloprovincialis.

    PubMed

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

    2013-01-01

    The increased use of engineered nanoparticles (ENPs) in consumer products raises the concern of environmental release and subsequent impacts in natural communities. We tested for physiological and demographic impacts of ZnO, a prevalent metal oxide ENP, on the mussel Mytilus galloprovincialis. We exposed mussels of two size classes, <4.5 and ≥ 4.5 cm shell length, to 0.1-2 mg l(-1) ZnO ENPs in seawater for 12 wk, and measured the effect on mussel respiration, accumulation of Zn, growth, and survival. After 12 wk of exposure to ZnO ENPs, respiration rates of mussels increased with ZnO concentration. Mussels had up to three fold more Zn in tissues than control groups after 12 wk of exposure, but patterns of Zn accumulation varied with mussel size and Zn concentrations. Small mussels accumulated Zn 10 times faster than large mussels at 0.5 mg l(-1), while large mussels accumulated Zn four times faster than small mussels at 2 mg l(-1). Mussels exposed to 2 mg l(-1) ZnO grew 40% less than mussels in our control group for both size classes. Survival significantly decreased only in groups exposed to the highest ZnO concentration (2 mg l(-1)) and was lower for small mussels than large. Our results indicate that ZnO ENPs are toxic to mussels but at levels unlikely to be reached in natural marine waters.

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

    PubMed

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

    2014-11-04

    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.

  5. Evaluation of engineered nanoparticle toxic effect on wastewater microorganisms: current status and challenges.

    PubMed

    Eduok, S; Martin, B; Villa, R; Nocker, A; Jefferson, B; Coulon, F

    2013-09-01

    The use of engineered nanoparticles (ENPs) in a wide range of products is associated with an increased concern for environmental safety due to their potential toxicological and adverse effects. ENPs exert antimicrobial properties through different mechanisms such as the formation of reactive oxygen species, disruption of physiological and metabolic processes. Although there are little empirical evidences on environmental fate and transport of ENPs, biosolids in wastewater most likely would be a sink for ENPs. However, there are still many uncertainties in relation to ENPs impact on the biological processes during wastewater treatment. This review provides an overview of the available data on the plausible effects of ENPs on AS and AD processes, two key biologically relevant environments for understanding ENPs-microbial interactions. It indicates that the impact of ENPs is not fully understood and few evidences suggest that ENPs could augment microbial-mediated processes such as AS and AD. Further to this, wastewater components can enhance or attenuate ENPs effects. Meanwhile it is still difficult to determine effective doses and establish toxicological guidelines, which is in part due to variable wastewater composition and inadequacy of current analytical procedures. Challenges associated with toxicity evaluation and data interpretation highlight areas in need for further research studies.

  6. [Behaviors of engineered nanoparticles in aquatic environments and impacts on marine phytoplankton].

    PubMed

    Li, Man-lu; Jiang, Yue-lu

    2015-01-01

    Engineered nanoparticles (ENPs) have shown invaluable societal benefits and applications in drug targeting, biological imaging and industrial products. ENPs enter the water body through various paths during the processes of production, usage and emission, therefore the behavior and the biosafety of ENPs in water bodies have attracted increasing attention. As the primary producer of ecosystems, phytoplankton provide nutrients, energy and oxygen for both themselves and organisms at higher trophic levels in the aquatic ecosystems. These primary producers may be exposed to the biological and unpredictable effects of this emergent pollutant to the aquatic ecosystems. Numerous studies have proved the toxic effects of ENPs on phytoplankton, but the mechanisms of entry into the aquatic organisms as well as the stability, fate and biotransformation in phytoplankton still remain unclear. Here, we present a review of the pathways of ENPs entering the water, the subsequent behavior and biological effects of ENPs on phytoplankton with an emphasis on latest findings and current knowledge. Future research and endeavors shall focus further on the understanding of mechanisms, fate and transport of ENPs in the aquatic ecosystems.

  7. 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 14 days 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.

  8. 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

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

    PubMed

    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

    2015-11-28

    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.

  10. Applying accelerator mass spectrometry for low-level detection of complex engineered nanoparticles in biological media.

    PubMed

    Wang, Binghui; Jackson, George S; Yokel, Robert A; Grulke, Eric A

    2014-08-01

    Complex engineered nanoparticles (CENPs), which have different core and surface components, are being developed for medicinal, pharmaceutical and industrial applications. One of the key challenges for environmental health and safety assessments of CENPs is to identify and quantity their transformations in biological environments. This study reports the effects of in vivo exposure of citrate-coated nanoalumina with different rare isotope labels on each component. This CENP was dosed to the rat and accelerator mass spectrometry (AMS) was used to quantify (26)Al, (14)C, and their ratio in the dosing material and tissue samples. For CENPs detected in the liver, the rare isotope ratio, (14)C/(26)Al, was 87% of the dosing material's ratio. The citrate coating on the nanoalumina in the liver was stable or, if it degraded, its metabolites were incorporated with nearby tissues. However, in brain and bone where little alumina was detected, the rare isotope ratio greatly exceeded that of the dosing material. Therefore, in the animal, citrate dissociated from CENPs and redistributed to brain and bone. Tracking both the core and surface components by AMS presents a new approach for characterizing transformations of CENPs components in biological milieu or environments.

  11. 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.

  12. 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.

  13. Surface engineering of macrophages with nanoparticles to generate a cell-nanoparticle hybrid vehicle for hypoxia-targeted drug delivery.

    PubMed

    Holden, Christopher A; Yuan, Quan; Yeudall, W Andrew; Lebman, Deborah A; Yang, Hu

    2010-02-02

    Tumors frequently contain hypoxic regions that result from a shortage of oxygen due to poorly organized tumor vasculature. Cancer cells in these areas are resistant to radiation- and chemotherapy, limiting the treatment efficacy. Macrophages have inherent hypoxia-targeting ability and hold great advantages for targeted delivery of anticancer therapeutics to cancer cells in hypoxic areas. However, most anticancer drugs cannot be directly loaded into macrophages because of their toxicity. In this work, we designed a novel drug delivery vehicle by hybridizing macrophages with nanoparticles through cell surface modification. Nanoparticles immobilized on the cell surface provide numerous new sites for anticancer drug loading, hence potentially minimizing the toxic effect of anticancer drugs on the viability and hypoxia-targeting ability of the macrophage vehicles. In particular, quantum dots and 5-(aminoacetamido) fluorescein-labeled polyamidoamine dendrimer G4.5, both of which were coated with amine-derivatized polyethylene glycol, were immobilized to the sodium periodate-treated surface of RAW264.7 macrophages through a transient Schiff base linkage. Further, a reducing agent, sodium cyanoborohydride, was applied to reduce Schiff bases to stable secondary amine linkages. The distribution of nanoparticles on the cell surface was confirmed by fluorescence imaging, and it was found to be dependent on the stability of the linkages coupling nanoparticles to the cell surface.

  14. Synthesis of Ca P nanoparticles and fabrication of Ca P/PHBV nanocomposite microspheres for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Duan, B.; Wang, M.; Zhou, W. Y.; Cheung, W. L.

    2008-11-01

    As the first step in producing totally bioresorbable osteoconductive composite scaffolds for bone tissue engineering using the selective laser sintering technology, bioresorbable nanoparticles of calcium phosphate (Ca-P) similar in composition to β-tricalcium phosphate were synthesized and Ca-P nanoparticle filled poly(hydroxybutyrate- co-hydroxyvalerate) (PHBV) microspheres were fabricated. The pH of the chemical reaction for Ca-P particle synthesis was found to have significant effects on the morphology and chemical composition of Ca-P precipitated. Ca-P particles produced at the pH of 10.0-11.0 were amorphous, had a Ca:P molar ratio of about 1.5, were spherical in shape and had sizes in the range of 10-30 nm. The Ca-P particles were used to form Ca-P nanocomposite microspheres through a solid-in-oil-in-water (S/O/W) emulsion solvent evaporation process. Ca-P nanoparticles were mostly encapsulated inside the microspheres and some Ca-P nanoparticles were superficially embedded on the microspheres. The Ca-P/PHBV microspheres had an average diameter of about 48 μm which is suitable for selective laser sintering for constructing osteoconductive composite scaffolds.

  15. Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials.

    PubMed

    Byeon, Jeong Hoon; Park, Jae Hong; Peters, Thomas M; Roberts, Jeffrey T

    2015-07-15

    The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. Accumulation and Toxicity of Copper Oxide Engineered Nanoparticles in a Marine Mussel

    PubMed Central

    Hanna, Shannon K.; Miller, Robert J.; Lenihan, Hunter S.

    2014-01-01

    Cu is an essential trace element but can be highly toxic to aquatic organisms at elevated concentrations. Greater use of CuO engineered nanoparticles (ENPs) may lead to increased concentrations of CuO ENPs in aquatic environments causing potential ecological injury. We examined the toxicity of CuO ENPs to marine mussels and the influence of mussels on the fate and transport of CuO ENPs. We exposed marine mussels to 1, 2, or 3 mg L−1 CuO ENPs for four weeks, and measured clearance rate, rejection, excretion and accumulation of Cu, and mussel shell growth. Mussel clearance rate was 48% less, and growth was 68% less, in mussels exposed to 3 mg L−1 than in control animals. Previous studies show 100% mortality at 1 mg Cu L−1, suggesting that CuO ENPs are much less toxic than ionic Cu, probably due to the slow dissolution rate of the ENPs. Mussels rejected and excreted CuO ENPs in biodeposits containing as much as 110 mg Cu g−1, suggesting the potential for magnification in sediments. Mussels exposed to 3 mg L−1 CuO ENPs accumulated 79.14 ± 12.46 μg Cu g−1 dry weight, which was 60 times more Cu than in control animals. Our results suggest that mussels have the potential to influence the fate and transport of CuO ENPs and potentially cause magnification of CuO ENPs in mussel bed communities, creating a significant source of Cu to marine benthos. PMID:28344235

  1. Engineering an Effective Immune Adjuvant by Designed Control of Shape and Crystallinity of Aluminum Oxyhydroxide Nanoparticles

    PubMed Central

    Sun, Bingbing; Ji, Zhaoxia; Liao, Yu-Pei; Wang, Meiying; Wang, Xiang; Dong, Juyao; Chang, Chong Hyun; Li, Ruibin; Zhang, Haiyuan; Nel, André E.; Xia, Tian

    2014-01-01

    Adjuvants based on aluminum salts (Alum) are commonly used in vaccines to boost the immune response against infectious agents. However, the detailed mechanism of how Alum enhances adaptive immunity and exerts its adjuvant immune effect remains unclear. Other than being comprised of micron-sized aggregates that include nanoscale particulates, Alum lacks specific physicochemical properties to explain activation of the innate immune system, including the mechanism by which aluminum-based adjuvants engage the NLRP3 inflammasome and IL-1β production. This is putatively one of the major mechanisms required for an adjuvant effect. Because we know that long aspect ratio nanomaterials trigger the NLRP3 inflammasome, we synthesized a library of aluminum oxyhydroxide (AlOOH) nanorods to determine whether control of the material shape and crystalline properties could be used to quantitatively assess NLRP3 inflammasome activation and linkage of the cellular response to the material’s adjuvant activities in vivo. Using comparison to commercial Alum, we demonstrate that the crystallinity and surface hydroxyl group display of AlOOH nanoparticles quantitatively impact the activation of the NLRP3 inflammasome in human THP-1 myeloid cells or murine bone marrow-derived dendritic cells (BMDCs). Moreover, these in vitro effects were correlated with the immunopotentiation capabilities of the AlOOH nanorods in a murine OVA immunization model. These results demonstrate that shape, crystallinity and hydroxyl content play an important role in NLRP3 inflammasome activation and are therefore useful for quantitative boosting of antigen-specific immune responses. These results show that the engineered design of aluminum-based adjuvants in combination with dendritic cell property-activity analysis can be used to design more potent aluminum-based adjuvants. PMID:24261790

  2. The effects of metallic engineered nanoparticles upon plant systems: An analytic examination of scientific evidence.

    PubMed

    Tolaymat, Thabet; Genaidy, Ash; Abdelraheem, Wael; Dionysiou, Dionysios; Andersen, Christian

    2017-02-01

    Recent evidence for the effects of metallic engineered nanoparticles (ENPs) on plants and plant systems was examined together with its implications for other constituents of the Society-Environment-Economy (SEE) system. In this study, we were particularly interested to determine whether or not metallic ENPs have both stimulatory and inhibitory effects upon plant performance. An emphasis was made to analyze the scientific evidence on investigations examining both types of effects in the same studies. Analysis of evidence demonstrated that metallic ENPs have both stimulatory and inhibitory effects mostly in well-controlled environments and soilless media. Nano zero-valent iron (nZVI) and Cu ENPs have potential for use as micronutrients for plant systems, keeping in mind the proper formulation at the right dose for each type of ENP. The concentration levels for the stimulatory effects of Cu ENPs are lower than for those for nZVI. Newer findings showed that extremely smaller concentrations of Au ENPs (smaller than those for nZVI and Cu ENPs) induce positive effects for plant growth, which is attributed to effects on secondary metabolites. Ag ENPs have demonstrated their usage as antimicrobial/pesticidal agents for plant protection; however, precautions should be taken to avoid higher concentrations not only for plant systems, but also, other constituents in the SEE. Further research is warranted to investigate the stimulatory and inhibitory effects of metallic ENPs in soil media in order to broaden the horizon of sustainable agriculture production in terms of higher and safer yields so as to meet the food requirements of human population.

  3. 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.

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

    NASA Astrophysics Data System (ADS)

    Sankar, Renu; Rahman, Pattanathu K. S. M.; Varunkumar, Krishnamoorthy; Anusha, Chidambaram; Kalaiarasi, Arunachalam; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

    2017-02-01

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

  5. Minimizing of the boundary friction coefficient in automotive engines using Al2O3 and TiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ali, Mohamed Kamal Ahmed; Xianjun, Hou; Elagouz, Ahmed; Essa, F. A.; Abdelkareem, Mohamed A. A.

    2016-12-01

    Minimizing of the boundary friction coefficient is critical for engine efficiency improvement. It is known that the tribological behavior has a major role in controlling the performance of automotive engines in terms of the fuel consumption. The purpose of this research is an experimental study to minimize the boundary friction coefficient via nano-lubricant additives. The tribological characteristics of Al2O3 and TiO2 nano-lubricants were evaluated under reciprocating test conditions to simulate a piston ring/cylinder liner interface in automotive engines. The nanoparticles were suspended in a commercially available lubricant in a concentration of 0.25 wt.% to formulate the nano-lubricants. The Al2O3 and TiO2 nanoparticles had sizes of 8-12 and 10 nm, respectively. The experimental results have shown that the boundary friction coefficient reduced by 35-51% near the top and bottom dead center of the stroke (TDC and BDC) for the Al2O3 and TiO2 nano-lubricants, respectively. The anti-wear mechanism was generated via the formation of protective films on the worn surfaces of the ring and liner. These results will be a promising approach for improving fuel economy in automotive.

  6. Application of an asymmetric flow field flow fractionation multi-detector approach for metallic engineered nanoparticle characterization--prospects and limitations demonstrated on Au nanoparticles.

    PubMed

    Hagendorfer, Harald; Kaegi, Ralf; Traber, Jacqueline; Mertens, Stijn F L; Scherrers, Roger; Ludwig, Christian; Ulrich, Andrea

    2011-11-14

    In this work we discuss about the method development, applicability and limitations of an asymmetric flow field flow fractionation (A4F) system in combination with a multi-detector setup consisting of UV/vis, light scattering, and inductively coupled plasma mass spectrometry (ICPMS). The overall aim was to obtain a size dependent-, element specific-, and quantitative method appropriate for the characterization of metallic engineered nanoparticle (ENP) dispersions. Thus, systematic investigations of crucial method parameters were performed by employing well characterized Au nanoparticles (Au-NPs) as a defined model system. For good separation performance, the A4F flow-, membrane-, and carrier conditions were optimized. To obtain reliable size information, the use of laser light scattering based detectors was evaluated, where an online dynamic light scattering (DLS) detector showed good results for the investigated Au-NP up to a size of 80 nm in hydrodynamic diameter. To adapt large sensitivity differences of the various detectors, as well as to guarantee long term stability and minimum contamination of the mass spectrometer a split-flow concept for coupling ICPMS was evaluated. To test for reliable quantification, the ICPMS signal response of ionic Au standards was compared to that of Au-NP. Using proper stabilization with surfactants, no difference for concentrations of 1-50 μg Au L(-1) in the size range from 5 to 80 nm for citrate stabilized dispersions was observed. However, studies using different A4F channel membranes showed unspecific particle-membrane interaction resulting in retention time shifts and unspecific loss of nanoparticles, depending on the Au-NP system as well as membrane batch and type. Thus, reliable quantification and discrimination of ionic and particular species was performed using ICPMS in combination with ultracentrifugation instead of direct quantification with the A4F multi-detector setup. Figures of merit were obtained, by comparing the

  7. Effects of engineered iron nanoparticles on the bryophyte, Physcomitrella patens (Hedw.) Bruch & Schimp, after foliar exposure.

    PubMed

    Canivet, L; Dubot, P; Garçon, G; Denayer, F-O

    2015-03-01

    The effects of iron nanoparticles on bryophytes (Physcomitrella patens) were studied following foliar exposure. We used iron nanoparticles (Fe-NP) representative of industrial emissions from the metallurgical industries. After a characterization of iron nanoparticles and the validation of nanoparticle internalization in cells, the effects (cytotoxicity, oxidative stress, lipid peroxidation of membrane) of iron nanoparticles were determined through the axenic culturing of Physcomitrella patens exposed at five different concentrations (5 ng, 50 ng, 500 ng, 5 µg and 50 µg per plant). Following exposure, the plant health, measured as ATP concentrations, was not impacted. Moreover, we studied oxidative stress in three ways: through the measure of reactive oxygen species (ROS) production, through malondialdehyde (MDA) production and also through glutathione regulation. At concentrations tested over a short period, the level of ROS, MDA and glutathione were not significantly disturbed.

  8. 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

    2016-08-03

    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.

  9. Surface-independent antibacterial coating using silver nanoparticle-generating engineered mussel glue.

    PubMed

    Jo, Yun Kee; Seo, Jeong Hyun; Choi, Bong-Hyuk; Kim, Bum Jin; Shin, Hwa Hui; Hwang, Byeong Hee; Cha, Hyung Joon

    2014-11-26

    During implant surgeries, antibacterial agents are needed to prevent bacterial infections, which can cause the formation of biofilms between implanted materials and tissue. Mussel adhesive proteins (MAPs) derived from marine mussels are bioadhesives that show strong adhesion and coating ability on various surfaces even in wet environment. Here, we proposed a novel surface-independent antibacterial coating strategy based on the fusion of MAP to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity. This sticky recombinant fusion protein enabled the efficient coating on target surface and the easy generation of silver nanoparticles on the coated-surface under mild condition. The biosynthesized silver nanoparticles showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria and also revealed good cytocompatibility with mammalian cells. In this coating strategy, MAP-silver binding peptide fusion proteins provide hybrid environment incorporating inorganic silver nanoparticle and simultaneously mediate the interaction of silver nanoparticle with surroundings. Moreover, the silver nanoparticles were fully synthesized on various surfaces including metal, plastic, and glass by a simple, surface-independent coating manner, and they were also successfully synthesized on a nanofiber surface fabricated by electrospinning of the fusion protein. Thus, this facile surface-independent silver nanoparticle-generating antibacterial coating has great potential to be used for the prevention of bacterial infection in diverse biomedical fields.

  10. 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.

  11. Development of environmental fate models for engineered nanoparticles--a case study of TiO2 nanoparticles in the Rhine River.

    PubMed

    Praetorius, Antonia; Scheringer, Martin; Hungerbühler, Konrad

    2012-06-19

    For a proactive risk assessment of engineered nanoparticles (ENPs) it is imperative to derive predicted environmental concentration (PEC) values for ENPs in different environmental compartments; PECs can then be compared to effect thresholds. From the basis of established multimedia environmental fate models for organic pollutants, we develop a new concept of environmental fate modeling for ENPs with process descriptions based on the specific properties of ENPs. Our new fate modeling framework is highly flexible and can be adjusted to different ENPs and various environmental settings. As a first case study, the fate and transport of TiO(2) NPs in the Rhine River is investigated. Predicted TiO(2) NP concentrations lie in the ng/L range in the water compartment and mg/kg in the sediment, which represents the main reservoir for the nanoparticles. We also find that a significant downstream transport of ENPs is possible. A fundamental process, the heteroaggregation between TiO(2) NPs and suspended particulate matter (SPM), is analyzed in more detail. Our modeling results demonstrate the importance of both the SPM properties (concentration, size, density) as well as the affinity of TiO(2) NPs and SPM, characterized by the attachment efficiency, α(het-agg), on the transport potential of ENPs in a surface water system.

  12. 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

  13. 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.

  14. 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.

  15. Recent advances on surface engineering of magnetic iron oxide nanoparticles and their biomedical applications.

    PubMed

    Gupta, Ajay Kumar; Naregalkar, Rohan R; Vaidya, Vikas Deep; Gupta, Mona

    2007-02-01

    Magnetic nanoparticles with appropriate surface coatings are increasingly being used clinically for various biomedical applications, such as magnetic resonance imaging, hyperthermia, drug delivery, tissue repair, cell and tissue targeting and transfection. This is because of the nontoxicity and biocompatibility demand that mainly iron oxide-based materials are predominantly used, despite some attempts to develop 'more magnetic nanomaterials' based on cobalt, nickel, gadolinium and other compounds. For all these applications, the material used for surface coating of the magnetic particles must not only be nontoxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. Magnetic nanoparticles can bind to drugs and an external magnetic field can be applied to trap them in the target site. By attaching the targeting molecules, such as proteins or antibodies, at particles surfaces, the latter may be directed to any cell, tissue or tumor in the body. In this review, different polymers/molecules that can be used for nanoparticle coating to stabilize the suspensions of magnetic nanoparticles under in vitro and in vivo situations are discussed. Some selected proteins/targeting ligands that could be used for derivatizing magnetic nanoparticles are also explored. We have reviewed the various biomedical applications with some of the most recent uses of magnetic nanoparticles for early detection of cancer, diabetes and atherosclerosis.

  16. 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.

  17. 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

  18. 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

  19. Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications.

    PubMed

    Gupta, Ajay Kumar; Gupta, Mona

    2005-06-01

    Superparamagnetic iron oxide nanoparticles (SPION) with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and in cell separation, etc. All these biomedical and bioengineering applications require that these nanoparticles have high magnetization values and size smaller than 100 nm with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. In addition, these applications need special surface coating of the magnetic particles, which has to be not only non-toxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. To this end, most work in this field has been done in improving the biocompatibility of the materials, but only a few scientific investigations and developments have been carried out in improving the quality of magnetic particles, their size distribution, their shape and surface in addition to characterizing them to get a protocol for the quality control of these particles. Nature of surface coatings and their subsequent geometric arrangement on the nanoparticles determine not only the overall size of the colloid but also play a significant role in biokinetics and biodistribution of nanoparticles in the body. The types of specific coating, or derivatization, for these nanoparticles depend on the end application and should be chosen by keeping a particular application in mind, whether it be aimed at inflammation response or anti-cancer agents. Magnetic nanoparticles can bind to drugs, proteins, enzymes, antibodies, or nucleotides and can be directed to an organ, tissue, or tumour using an external magnetic field or can be heated in alternating magnetic fields for use in hyperthermia. This review discusses the synthetic chemistry, fluid stabilization and

  20. 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.

  1. SiO2 aerosol nanoparticle reactor for occupational health and safety studies.

    PubMed

    Ostraat, Michele L; Swain, Keith A; Krajewski, James J

    2008-06-01

    Important questions are emerging about potential occupational safety, toxicological, and ecotoxicological effects and occupational inhalation exposure risks to engineered aerosol nanoparticles. Although multiple avenues are available to synthesize nanoparticles, few tools are accessible to industrial hygienists and inhalation toxicologists to produce well-characterized aerosols of known aerosol size distribution and particle number concentration that are stable, simple, and robust to operate. This article describes a SiO(2) aerosol nanoparticle reactor that has been developed as a tool for the study of the safety, health, and environmental consequences of exposure to nanoparticle synthesis and processing. The SiO(2) aerosol nanoparticle reactor is capable of stable, long-term synthesis of amorphous SiO(2) aerosol nanoparticles from d(50) = 10-70 nm at particle concentrations approximately 10(4)-10(7)particles/cm(3) that does not produce halogen-containing byproducts and does not require daily monitoring of the particle size distribution. This reactor is designed to produce a well-characterized aerosol to enable subsequent testing with a continuous, stable supply of aerosol nanoparticles (i) to facilitate inhalation toxicology studies, (ii) to measure explosion characteristics of aerosol nanoparticles, (iii) to determine the barrier efficacy for respirator filtration, bag house exhaust, and personal protective garment media challenged with diverse aerosol nanoparticles, and (iv) to develop airborne monitoring technologies for verifying workplace safety protocols. This article details reactor design, synthesis parameters, and instruments available to characterize the resulting aerosol nanoparticle size distributions.

  2. 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

  3. Detecting and Number Counting of Single Engineered Nanoparticles by Digital Particle Polymerase Chain Reaction.

    PubMed

    Paunescu, Daniela; Mora, Carlos A; Querci, Lorenzo; Heckel, Reinhard; Puddu, Michela; Hattendorf, Bodo; Günther, Detlef; Grass, Robert N

    2015-10-27

    The concentrations of nanoparticles present in colloidal dispersions are usually measured and given in mass concentration (e.g. mg/mL), and number concentrations can only be obtained by making assumptions about nanoparticle size and morphology. Additionally traditional nanoparticle concentration measures are not very sensitive, and only the presence/absence of millions/billions of particles occurring together can be obtained. Here, we describe a method, which not only intrinsically results in number concentrations, but is also sensitive enough to count individual nanoparticles, one by one. To make this possible, the sensitivity of the polymerase chain reaction (PCR) was combined with a binary (=0/1, yes/no) measurement arrangement, binomial statistics and DNA comprising monodisperse silica nanoparticles. With this method, individual tagged particles in the range of 60-250 nm could be detected and counted in drinking water in absolute number, utilizing a standard qPCR device within 1.5 h of measurement time. For comparison, the method was validated with single particle inductively coupled plasma mass spectrometry (sp-ICPMS).

  4. Surface engineering of Co and FeCo nanoparticles for biomedical application

    NASA Astrophysics Data System (ADS)

    Behrens, Silke; Bönnemann, Helmut; Matoussevitch, Nina; Gorschinski, Angelika; Dinjus, Eckhard; Habicht, Wilhelm; Bolle, Jens; Zinoveva, Svetlana; Palina, Natalie; Hormes, Josef; Modrow, Hartwig; Bahr, Stephan; Kempter, Volker

    2006-09-01

    Monodisperse Co, Fe, and FeCo nanoparticles are prepared via thermal decomposition of metal carbonyls in the presence of aluminium alkyls, yielding air-stable magnetic metal nanoparticles after surface passivation. The particles are characterized by electron microscopy (SEM, TEM, ESI), electron spectroscopy (MIES, UPS, and XPS) and x-ray absorption spectroscopy (EXAFS). The particles are peptized by surfactants to form stable magnetic fluids in various organic media and water, exhibiting a high volume concentration and a high saturation magnetization. In view of potential biomedical applications of the particles, several procedures for surface modification are presented, including peptization by functional organic molecules, silanization, and in situ polymerization.

  5. 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

  6. Hotspots engineering by grafting Au@Ag core-shell nanoparticles on the Au film over slightly etched nanoparticles substrate for on-site paraquat sensing.

    PubMed

    Wang, Chaoguang; Wu, Xuezhong; Dong, Peitao; Chen, Jian; Xiao, Rui

    2016-12-15

    Paraquat (PQ) pollutions are ultra-toxic to human beings and hard to be decomposed in the environment, thus requiring an on-site detection strategy. Herein, we developed a robust and rapid PQ sensing strategy based on the surface-enhanced Raman scattering (SERS) technique. A hybrid SERS substrate was prepared by grafting the Au@Ag core-shell nanoparticles (NPs) on the Au film over slightly etched nanoparticles (Au FOSEN). Hotspots were engineered at the junctions as indicated by the finite difference time domain calculation. SERS performance of the hybrid substrate was explored using p-ATP as the Raman probe. The hybrid substrate gives higher enhancement factor comparing to either the Au FOSEN substrate or the Au@Ag core-shell NPs, and exhibits excellent reproducibility, homogeneity and stability. The proposed SERS substrates were prepared in batches for the practical PQ sensing. The total analysis time for a single sample, including the pre-treatment and measurement, was less than 5min with a PQ detection limit of 10nM. Peak intensities of the SERS signal were plotted as a function of the PQ concentrations to calibrate the sensitivity by fitting the Hill's equation. The plotted calibration curve showed a good log-log linearity with the coefficient of determination of 0.98. The selectivity of the sensing proposal was based on the "finger print" Raman spectra of the analyte. The proposed substrate exhibited good recovery when it applied to real water samples, including lab tap water, bottled water, and commercially obtained apple juice and grape juice. This SERS-based PQ detection method is simple, rapid, sensitive and selective, which shows great potential in pesticide residue and additives abuse monitoring.

  7. 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.

  8. 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...

  9. 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…

  10. 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.

  11. 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.

  12. Hepatoprotective effect of engineered silver nanoparticles coated bioactive compounds against diethylnitrosamine induced hepatocarcinogenesis in experimental mice.

    PubMed

    Prasannaraj, Govindaraj; Venkatachalam, Perumal

    2017-02-01

    Nanoparticle based drug delivery can rapidly improves the therapeutic potential of anti-cancer agents. The present study focused to evaluate the hepatoprotective activity of silver nanoparticles (AgNPs) synthesized using aqueous extracts of Andrographis paniculata leaves (ApAgNPs) and Semecarpus anacardium nuts (SaAgNPs) against diethylnitrosamine (DEN) induced liver cancer in mice model. The physico-chemical properties of synthesized AgNPs were characterized by Fourier transform infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX) spectrum, Zeta potential and Dynamic Light Scattering (DLS) analysis. The surface plasmon resonance (SPR) absorption spectrum revealed a strong peak at 420nm for both SaAgNPs and ApAgNPs. FTIR results exhibited the presence of possible functional groups in the synthesized AgNPs. TEM analysis determined the hexagonal, and spherical shape of the synthesized silver nanoparticles. The XRD and SAED pattern confirmed the crystalline nature and crystalline size of the AgNPs. EDX result clearly showed strong silver signals in the range between 2 and 4keV. Zeta potential measurements indicated a sharp peak at -3.93 and -13.8mV for ApAgNPs and SaAgNPs, respectively. DLS measurement expressed the particle size distribution was 70 and 60nm for ApAgNPs and SaAgNPs, respectively. DEN (20mg/kg b.wt.) was subjected to induce liver cancer in mice for 8weeks and treated with biosynthesized silver nanoparticles. Interestingly, ApAgNPs and SaAgNPs treated DEN induced animal groups show a decreased level of aspartate amino transferase (AST), alanine amino transferase (ALT), serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) activity and elevated level of catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) activity over untreated DEN control

  13. Engineering triiodothyronine (T3) nanoparticle for use in ischemic brain stroke.

    PubMed

    Mdzinarishvili, Alexander; Sutariya, Vijaykumar; Talasila, Phani K; Geldenhuys, Werner J; Sadana, Prabodh

    2013-08-01

    A potential means of pharmacological management of ischemic stroke is rapid intervention using potent neuroprotective agents. Thyroid hormone (T3) has been shown to protect against ischemic damage in middle cerebral artery occlusion (MCAO) model of ischemic brain stroke. While thyroid hormone is permeable across the blood-brain barrier, we hypothesized that efficacy of thyroid hormone in ischemic brain stroke can be enhanced by encapsulation in nanoparticulate delivery vehicles. We tested our hypothesis by generating poly-(lactide-co-glycolide)-polyethyleneglycol (PLGA-b-PEG) nanoparticles that are either coated with glutathione or are not coated. We have previously reported that glutathione coating of PLGA-PEG nanoparticles is an efficient means of brain targeted drug delivery. Encapsulation of T3 in PLGA-PEG delivery vehicle resulted in particles that were in the nano range and exhibited a zeta potential of -6.51 mV (uncoated) or -1.70 mV (coated). We observed that both glutathione-coated and uncoated nanoparticles are taken up in cells wherein they stimulated the expression of thyroid hormone response element driven reporter robustly. In MCAO model of ischemic stroke, significant benefit of administering T3 in nanoparticulate form was observed over injection of a T3 solution. A 34 % decrease in tissue infarction and a 59 % decrease in brain edema were seen upon administration of T3 solution in MCAO stroke model. Corresponding measurements for uncoated T3 nanoparticles were 51 % and 68 %, whereas for the glutathione coated were 58 % and 75 %. Our study demonstrates that using nanoparticle formulations can significantly improve the efficacy of neuroprotective drugs in ischemic brain stroke.

  14. A review of selected engineered nanoparticles in the atmosphere: sources, transformations, and techniques for sampling and analysis.

    PubMed

    Majestic, Brian J; Erdakos, Garnet B; Lewandowski, Michael; Oliver, Karen D; Willis, Robert D; Kleindienst, Tadeusz E; Bhave, Prakash V

    2010-01-01

    A state-of-the-science review was undertaken to identify and assess sampling and analysis methods to detect and quantify selected nanomaterials (NMs) in the ambient atmosphere. The review is restricted to five types of NMs of interest to the Office of Research and Development Nanomaterial Research Strategy (U.S. Environmental Protection Agency): cerium oxide, titanium dioxide, carbon nanostructures (carbon nanotubes and fullerenes), zero-valent iron, and silver nanoparticles. One purpose was determining the extent to which present-day ultrafine sampling and analysis methods may be sufficient for identifying and possibly quantifying engineered NMs (ENMs) in ambient air. Conventional sampling methods for ultrafines appear to require modifications. For cerium and titanium, background levels from natural sources make measurement of ENMs difficult to quantify. In cases where field studies have been performed, identification from bulk analysis samples have been made. Further development of methods is needed to identify these NMs, especially in specific size fractions of ambient aerosols.

  15. Plasmonic effect of Ag nanoparticles in a SiON antireflective coating: engineering rules and physical barrier

    NASA Astrophysics Data System (ADS)

    Lecler, S.; Bastide, S.; Tan, J.; Qu, M.; Slaoui, A.; Fix, T.

    2016-10-01

    Surface plasmon polaritons have been proposed in the architectures of several solar cells as a way to enhance light collection and thus to increase their efficiency. Here, Ag nanoparticles (NPs) are embedded in a SiON antireflective layer using an electroless technique. The plasmonic effects are modeled and observed experimentally for NPs 5 to 200 nm in size. The systematic comparison of scattering and extinction efficiencies computed as a function of the NPs and surrounding medium properties allows establishing engineering rules, validated by the experimental measurements. The fact that Ag NPs larger than 30 nm mainly contribute to light scattering and therefore to optical path enlargement (green-red light), whereas those smaller than 15 nm absorb light by light trapping (blue-green), is demonstrated and physically explained. A physical barrier making it impossible to shift the dominant resonance beyond 650 nm is pointed out.

  16. Long-term effects of engineered nanoparticles on enzyme activity and functional bacteria in wastewater treatment plants.

    PubMed

    Zheng, Xiong; Huang, Haining; Su, Yinglong; Wei, Yuanyuan; Chen, Yinguang

    2015-01-01

    The pervasive use of engineered nanoparticles (NPs) in a wide range of fields raises concerns about their potential environmental impacts. Previous studies confirmed that some NPs had already entered wastewater treatment plants (WWTPs). Wastewater nutrient removal depends on the metabolisms of activated sludge bacteria and their related key enzymes. Therefore, this study compared the possible influences of Al2O3, SiO2, TiO2, and ZnO NPs on the key enzymes activities and microbial community structures involved in wastewater treatment facilities. It was found that long-term exposure to these NPs significantly affected the microbial communities and changed the relative abundances of key functional bacteria, such as ammonia-oxidizing bacteria. Also, the gene expressions and catalytic activities of essential enzymes, such as ammonia monooxygenase, nitrite oxidoreductase, nitrate reductase, and nitrite reductase, were decreased, which finally resulted in a lower efficiency of biological nitrogen removal.

  17. PEGylated nanoparticles bind to and alter amyloid-beta peptide conformation: toward engineering of functional nanomedicines for Alzheimer's disease.

    PubMed

    Brambilla, Davide; Verpillot, Romain; Le Droumaguet, Benjamin; Nicolas, Julien; Taverna, Myriam; Kóňa, Juraj; Lettiero, Barbara; Hashemi, S Hossein; De Kimpe, Line; Canovi, Mara; Gobbi, Marco; Nicolas, Valérie; Scheper, Wiep; Moghimi, S Moein; Tvaroška, Igor; Couvreur, Patrick; Andrieux, Karine

    2012-07-24

    We have demonstrated that the polyethylene glycol (PEG) corona of long-circulating polymeric nanoparticles (NPs) favors interaction with the amyloid-beta (Aβ(1-42)) peptide both in solution and in serum. The influence of PEGylation of poly(alkyl cyanoacrylate) and poly(lactic acid) NPs on the interaction with monomeric and soluble oligomeric forms of Aβ(1-42) peptide was demonstrated by capillary electrophoresis, surface plasmon resonance, thioflavin T assay, and confocal microscopy, where the binding affected peptide aggregation kinetics. The capture of peptide by NPs in serum was also evidenced by fluorescence spectroscopy and ELISA. Moreover, in silico and modeling experiments highlighted the mode of PEG interaction with the Aβ(1-42) peptide and its conformational changes at the nanoparticle surface. Finally, Aβ(1-42) peptide binding to NPs affected neither complement activation in serum nor apolipoprotein-E (Apo-E) adsorption from the serum. These observations have crucial implications in NP safety and clearance kinetics from the blood. Apo-E deposition is of prime importance since it can also interact with the Aβ(1-42) peptide and increase the affinity of NPs for the peptide in the blood. Collectively, our results suggest that these engineered long-circulating NPs may have the ability to capture the toxic forms of the Aβ(1-42) peptide from the systemic circulation and potentially improve Alzheimer's disease condition through the proposed "sink effect".

  18. 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.

  19. Vault Nanoparticles Engineered with the Protein Transduction Domain, TAT48, Enhances Cellular Uptake

    PubMed Central

    Yang, Jian; Srinivasan, Aswin; Sun, Yang; Mrazek, Jan; Shu, Zhanyong; Kickhoefer, Valerie A.

    2013-01-01

    Vaults are naturally-occurring ribonucleoprotein particles found in nearly all eukaryotic cells. They were named for their morphological resemblance to the vaulted ceilings of gothic cathedrals. These ubiquitous nanoparticles are quite abundant with 104-106 copies found in the cytoplasm depending on cell type. The structural shell of the particle can self-assemble from 78 copies of a single protein, the major vault protein. This finding has allowed vaults to be bioengineered, resulting in a variety of new functions and capabilities directed toward overcoming many limitations posed by current gene and drug delivery systems. In this study, we demonstrate that recombinant vaults, with the addition of a cell penetration peptide, TAT, can be rapidly delivered to cells in vitro with significantly elevated binding and uptake efficiency. This TAT-vault nanoparticle could be a valuable tool for improving the retention and penetration of therapeutic drugs at tumor sites. PMID:22785558

  20. 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.

  1. Fe3O4 nanoparticles engineered for plasmid DNA delivery to Escherichia coli

    NASA Astrophysics Data System (ADS)

    Saei, Amir Ata; Barzegari, Abolfazl; Majd, Mostafa Heidari; Asgari, Davoud; Omidi, Yadollah

    2014-08-01

    Heat shock treatment is the most popular method for transformation of Escherichia coli. We have used 19-nm Fe3O4 nanoparticles for improving heat shock protocol. PGEM- T (3,000 bp) and pCAMBIA (8,428 bp) were used as test plasmids for transformation of competent E. coli cells (strains DH5α and Jm107) obtained from heat shock- and CaCl2-treated bacteria. A combination of heat shock and Fe3O4 nanoparticles led to a significant increase (6-10 fold) in number of transformed colonies in comparison with heat shock alone. The percent increase in transformation efficiency was higher for larger pCAMBIA plasmids compared to PGEM- T. The transformation efficiency decreased in the absence of CaCl2 and increased by addition of glycerol to the bacterial culture.

  2. Sampling for Airborne Radioactivity

    DTIC Science & Technology

    2007-10-01

    compared to betas, gammas and neutrons. For an airborne radioactivity detection system, it is most important to be able to detect alpha particles and... Airborne radioactive particles may emit alpha, beta, gamma or neutron radiation, depending on which radioisotope is present. From a health perspective...

  3. Seamless Integration of Detection and Therapy for Breast Cancer using Targeted Engineered Nanoparticles

    DTIC Science & Technology

    2007-06-01

    have spread to regional lymph nodes (stage III). Overall, 50% of surgically treated patients sufferCorresponding author: Fortina, P. (paolo.fortina...Detection of lymph node involvement in hematologic malignancies using micromagnetic resonance lymphan- giography with a gadolinum-labeled dendrimer...nanoparticle. Neoplasia 7, 984–991 42 Kobayashi, H. et al. (2004) Lymphatic drainage imaging of breast cancer in mice by micro-magnetic resonance

  4. 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(ɛ-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).

  5. Engineered nanoparticles against MDR in cancer: The state of the art and its prospective

    PubMed Central

    Greig, Nigel H.; Kamal, Mohammad Amjad; Midoux, Patrick; Pichon, Chantal

    2016-01-01

    Cancer is a highly heterogeneous disease, both within a single patient as well as between patients, and is the leading cause of death worldwide. A variety of mono and combinational therapies, including chemotherapy, have been developed and refined over recent years for its effective treatment. However, the evolution of chemotherapeutic resistance or multidrug resistance (MDR) in cancer has become a major challenge to successful chemotherapy. MDR is a complex process that combines multifaceted non-cellular and cellular-based mechanisms. Research in the area of cancer nanotechnology over the past two decades has reached the point where smartly designed nanoparticles with targeting ligands can aid successful chemotherapy by preferentially accumulating within the tumor region through means of active and passive targeting to overcome MDR, and simultaneously reduce the off-target accumulation of their payload. Such nanoparticle formulations – sometimes termed nanomedicines - are at different stages of cancer clinical trials and show promise in resistant cases. Nanoparticles as chemotherapeutics carriers provide the opportunity to have multiple payloads of drug and/or imaging agents for combinational and theranostic therapy. Moreover, nanotechnology has the potential to combine new treatment strategies, such as near-infrared (NIR), magnetic resonance imaging (MRI), and high intensity focused ultrasound (HIFU) into cancer chemotherapy and imaging. Here we discuss the cellular/non-cellular factors that underpin MDR in cancer, and the potential of nanomedicines to combat MDR, along with recent advances in combining nanotechnology with other approaches in cancer therapy. PMID:27319945

  6. Engineering a well-ordered, functional protein-gold nanoparticle assembly.

    PubMed

    Cheung-Lau, Jasmina C; Liu, Dage; Pulsipher, Katherine W; Liu, Weiren; Dmochowski, Ivan J

    2014-01-01

    The study of interactions between proteins and nanoparticles is important to advancing applications of nanoparticles in biology, medicine, and materials science. Here, we report the encapsulation of a 5-nm diameter gold nanoparticle (AuNP) by thermophilic ferritin (tF), achieved in nearly quantitative yield under mild conditions that preserved the secondary structure, ferroxidase activity, and thermal stability of the native, 4-helix bundle protein subunits. Chromatography-based assays determined that stable protein assembly around AuNPs occurred on long time scales (~48h) and was reversible. Apparent association constants were determined at 25°C for equilibrated tF-BSPP-capped AuNP samples (KA=(2.1±0.4)×10(78)M(-11)) and compared favorably to salt-assembled tF samples (KA=(2.2±0.5)×10(68)M(-11)) at the same protein concentration (0.3mg/mL). Finally, addition of gold ions and mild reducing agent to the tF-AuNP assembly produced 8-nm diameter AuNPs with surface plasmon resonance band unchanged at 520nm, indicative of templating by the protein shell.

  7. New insight into artifactual phenomena during in vitro toxicity assessment of engineered nanoparticles: study of TNF-α adsorption on alumina oxide nanoparticle.

    PubMed

    Pailleux, Mélanie; Boudard, Delphine; Pourchez, Jérémie; Forest, Valérie; Grosseau, Philippe; Cottier, Michèle

    2013-04-01

    Biomolecules can be adsorbed on nanoparticles (NPs) and degraded during in vitro toxicity assays. These artifactual phenomena could lead to misinterpretation of biological activity, such as false-negative results. To avoid possible underestimation of cytokine release after contact between NP and cells, we propose a methodology to account for these artifactual phenomena and lead to accurate measurements. We focused on the pro-inflammatory cytokine tumor necrosis factor TNF-α. We studied well-characterized boehmite engineered NP [aluminum oxide hydroxide, AlO(OH)]. The rate of TNF-α degradation and its adsorption (on boehmite and on the walls of wells) were determined in cell-free conditions by adding a known TNF-α concentration (1500 pg/ml) under various experimental conditions. After a 24-h incubation, we quantified that 7 wt.% of the initial TNF-α was degraded over time, 6 wt.% adsorbed on the walls of 96-well plates, and 13 wt.% adsorbed on the boehmite surface. Finally, boehmite NP were incubated with murine macrophages (RAW 264.7 cell line). The release of TNF-α was assessed for boehmite NP and the experimental data were corrected considering the artifactual phenomena, which accounted for about 20-30% of the total.

  8. 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

  9. 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

  10. 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

    2014-06-03

    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.

  11. 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

  12. 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

  13. The impact of engineered cobalt, iron, nickel and silver nanoparticles on soil bacterial diversity under field conditions

    NASA Astrophysics Data System (ADS)

    Shah, Vishal; Collins, Daniel; Walker, Virginia K.; Shah, Shreya

    2014-01-01

    Our understanding of how engineered nanoparticles (NPs) migrate through soil and affect microbial communities is scarce. In the current study we examined how metal NPs, including those from the iron triad (iron, cobalt and nickel), moved through pots of soil maintained under winter field conditions for 50 days, when mesophilic bacteria may not be dividing. Based on total metal analysis, cobalt and nickel were localized in the top layer of soil, even after exposure to high precipitation and freeze-thaw cycles. In contrast, a bimodal distribution of silver was observed. Due to high endogenous levels of iron, the migration pattern of these NPs could not be determined. Pyrosequence analysis of the bacterial communities revealed that there was no significant engineered NP-mediated decline in microbial richness. However, analysis of individual genera showed that Sphingomonas and Lysobacter were represented by fewer sequences in horizons containing elevated metal levels whereas there was an increase in the numbers of Flavobacterium and Niastella. Collectively, the results indicate that along with the differential migration behavior of NPs in the soil matrix, their impact on soil bacterial diversity appears to be dependent on environmental parameters.

  14. 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

  15. 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.

  16. Study on analysis from sources of error for Airborne LIDAR

    NASA Astrophysics Data System (ADS)

    Ren, H. C.; Yan, Q.; Liu, Z. J.; Zuo, Z. Q.; Xu, Q. Q.; Li, F. F.; Song, C.

    2016-11-01

    With the advancement of Aerial Photogrammetry, it appears that to obtain geo-spatial information of high spatial and temporal resolution provides a new technical means for Airborne LIDAR measurement techniques, with unique advantages and broad application prospects. Airborne LIDAR is increasingly becoming a new kind of space for earth observation technology, which is mounted by launching platform for aviation, accepting laser pulses to get high-precision, high-density three-dimensional coordinate point cloud data and intensity information. In this paper, we briefly demonstrates Airborne laser radar systems, and that some errors about Airborne LIDAR data sources are analyzed in detail, so the corresponding methods is put forwarded to avoid or eliminate it. Taking into account the practical application of engineering, some recommendations were developed for these designs, which has crucial theoretical and practical significance in Airborne LIDAR data processing fields.

  17. 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

  18. Provenance information as a tool for addressing engineered nanoparticle reproducibility challenges

    PubMed Central

    Baer, Donald R.; Munusamy, Prabhakaran; Thrall, Brian D.

    2016-01-01

    Nanoparticles of various types are of increasing research and technological importance in biological and other applications. Difficulties in the production and delivery of nanoparticles with consistent and well defined properties appear in many forms and have a variety of causes. Among several issues are those associated with incomplete information about the history of particles involved in research studies, including the synthesis method, sample history after synthesis, including time and nature of storage, and the detailed nature of any sample processing or modification. In addition, the tendency of particles to change with time or environmental condition suggests that the time between analysis and application is important and some type of consistency or verification process can be important. The essential history of a set of particles can be identified as provenance information and tells the origin or source of a batch of nano-objects along with information related to handling and any changes that may have taken place since it was originated. A record of sample provenance information for a set of particles can play a useful role in identifying some of the sources and decreasing the extent of particle variability and the lack of reproducibility observed by many researchers. PMID:27936809

  19. 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.

  20. Sensitive detection of copper ions via ion-responsive fluorescence quenching of engineered porous silicon nanoparticles

    NASA Astrophysics Data System (ADS)

    Hwang, Jangsun; Hwang, Mintai P.; Choi, Moonhyun; Seo, Youngmin; Jo, Yeonho; Son, Jaewoo; Hong, Jinkee; Choi, Jonghoon

    2016-10-01

    Heavy metal pollution has been a problem since the advent of modern transportation, which despite efforts to curb emissions, continues to play a critical role in environmental pollution. Copper ions (Cu2+), in particular, are one of the more prevalent metals that have widespread detrimental ramifications. From this perspective, a simple and inexpensive method of detecting Cu2+ at the micromolar level would be highly desirable. In this study, we use porous silicon nanoparticles (NPs), obtained via anodic etching of Si wafers, as a basis for undecylenic acid (UDA)- or acrylic acid (AA)-mediated hydrosilylation. The resulting alkyl-terminated porous silicon nanoparticles (APS NPs) have enhanced fluorescence stability and intensity, and importantly, exhibit [Cu2+]-dependent quenching of fluorescence. After determining various aqueous sensing conditions for Cu2+, we demonstrate the use of APS NPs in two separate applications – a standard well-based paper kit and a portable layer-by-layer stick kit. Collectively, we demonstrate the potential of APS NPs in sensors for the effective detection of Cu2+.

  1. Sensitive detection of copper ions via ion-responsive fluorescence quenching of engineered porous silicon nanoparticles

    PubMed Central

    Hwang, Jangsun; Hwang, Mintai P.; Choi, Moonhyun; Seo, Youngmin; Jo, Yeonho; Son, Jaewoo; Hong, Jinkee; Choi, Jonghoon

    2016-01-01

    Heavy metal pollution has been a problem since the advent of modern transportation, which despite efforts to curb emissions, continues to play a critical role in environmental pollution. Copper ions (Cu2+), in particular, are one of the more prevalent metals that have widespread detrimental ramifications. From this perspective, a simple and inexpensive method of detecting Cu2+ at the micromolar level would be highly desirable. In this study, we use porous silicon nanoparticles (NPs), obtained via anodic etching of Si wafers, as a basis for undecylenic acid (UDA)- or acrylic acid (AA)-mediated hydrosilylation. The resulting alkyl-terminated porous silicon nanoparticles (APS NPs) have enhanced fluorescence stability and intensity, and importantly, exhibit [Cu2+]-dependent quenching of fluorescence. After determining various aqueous sensing conditions for Cu2+, we demonstrate the use of APS NPs in two separate applications – a standard well-based paper kit and a portable layer-by-layer stick kit. Collectively, we demonstrate the potential of APS NPs in sensors for the effective detection of Cu2+. PMID:27752120

  2. 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.

  3. Provenance information as a tool for addressing engineered nanoparticle reproducibility challenges

    SciTech Connect

    Baer, Donald R.; Munusamy, Prabhakaran; Thrall, Brian D.

    2016-12-01

    Nanoparticles of various types are of increasing research and technological importance in biological and other applications. Difficulties in the production and delivery of nanoparticles with consistent and well defined properties appear in many forms and have a variety of causes. Among several issues are those associated with incomplete information about the history of particles involved in research studies including the synthesis method, sample history after synthesis including time and nature of storage and the detailed nature of any sample processing or modification. In addition, the tendency of particles to change with time or environmental condition suggests that the time between analysis and application is important and some type of consistency or verification process can be important. The essential history of a set of particles can be identified as provenance information tells the origin or source of a batch of nano-objects along with information related to handling and any changes that may have taken place since it was originated. A record of sample provenance information for a set of particles can play a useful role in identifying some of the sources and decreasing the extent of particle variability and the observed lack of reproducibility observed by many researchers.

  4. 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...

  5. 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...

  6. Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis.

    PubMed

    Johnson, Monique E; Hanna, Shannon K; Montoro Bustos, Antonio R; Sims, Christopher M; Elliott, Lindsay C C; Lingayat, Akshay; Johnston, Adrian C; Nikoobakht, Babak; Elliott, John T; Holbrook, R David; Scott, Keana C K; Murphy, Karen E; Petersen, Elijah J; Yu, Lee L; Nelson, Bryant C

    2017-01-24

    For environmental studies assessing uptake of orally ingested engineered nanoparticles (ENPs), a key step in ensuring accurate quantification of ingested ENPs is efficient separation of the organism from ENPs that are either nonspecifically adsorbed to the organism and/or suspended in the dispersion following exposure. Here, we measure the uptake of 30 and 60 nm gold nanoparticles (AuNPs) by the nematode, Caenorhabditis elegans, using a sucrose density gradient centrifugation protocol to remove noningested AuNPs. Both conventional inductively coupled plasma mass spectrometry (ICP-MS) and single particle (sp)ICP-MS are utilized to measure the total mass and size distribution, respectively, of ingested AuNPs. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) imaging confirmed that traditional nematode washing procedures were ineffective at removing excess suspended and/or adsorbed AuNPs after exposure. Water rinsing procedures had AuNP removal efficiencies ranging from 57 to 97% and 22 to 83%, while the sucrose density gradient procedure had removal efficiencies of 100 and 93 to 98%, respectively, for the 30 and 60 nm AuNP exposure conditions. Quantification of total Au uptake was performed following acidic digestion of nonexposed and Au-exposed nematodes, whereas an alkaline digestion procedure was optimized for the liberation of ingested AuNPs for spICP-MS characterization. Size distributions and particle number concentrations were determined for AuNPs ingested by nematodes with corresponding confirmation of nematode uptake via high-pressure freezing/freeze substitution resin preparation and large-area SEM imaging. Methods for the separation and in vivo quantification of ENPs in multicellular organisms will facilitate robust studies of ENP uptake, biotransformation, and hazard assessment in the environment.

  7. 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

  8. Surface engineering of nanoparticles in suspension for particle based bio-sensing.

    PubMed

    Sen, Tapas; Bruce, Ian J

    2012-01-01

    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.

  9. Engineering of self-assembled nanoparticle platform for precisely controlled combination drug therapy

    PubMed Central

    Kolishetti, Nagesh; Dhar, Shanta; Valencia, Pedro M.; Lin, Lucy Q.; Karnik, Rohit; Lippard, Stephen J.; Langer, Robert; Farokhzad, Omid C.

    2010-01-01

    The genomic revolution has identified therapeutic targets for a plethora of diseases, creating a need to develop robust technologies for combination drug therapy. In the present work, we describe a self-assembled polymeric nanoparticle (NP) platform to target and control precisely the codelivery of drugs with varying physicochemical properties to cancer cells. As proof of concept, we codelivered cisplatin and docetaxel (Dtxl) to prostate cancer cells with synergistic cytotoxicity. A polylactide (PLA) derivative with pendant hydroxyl groups was prepared and conjugated to a platinum(IV) [Pt(IV)] prodrug, c,t,c-[Pt(NH3)2(O2CCH2CH2COOH)(OH)Cl2] [PLA-Pt(IV)]. A blend of PLA-Pt(IV) functionalized polymer and carboxyl-terminated poly(d,l-lactic-co-glycolic acid)-block-poly(ethylene glycol) copolymer in the presence or absence of Dtxl, was converted, in microfluidic channels, to NPs with a diameter of ∼100 nm. This process resulted in excellent encapsulation efficiency (EE) and high loading of both hydrophilic platinum prodrug and hydrophobic Dtxl with reproducible EEs and loadings. The surface of the NPs was derivatized with the A10 aptamer, which binds to the prostate-specific membrane antigen (PSMA) on prostate cancer cells. These NPs undergo controlled release of both drugs over a period of 48–72 h. Targeted NPs were internalized by the PSMA-expressing LNCaP cells via endocytosis, and formation of cisplatin 1,2-d(GpG) intrastrand cross-links on nuclear DNA was verified. In vitro toxicities demonstrated superiority of the targeted dual-drug combination NPs over NPs with single drug or nontargeted NPs. This work reveals the potential of a single, programmable nanoparticle to blend and deliver a combination of drugs for cancer treatment. PMID:20921363

  10. Effects on Fuel Consumption and Diesel Engine Deposits from Nano-Particle Oil Additive

    DTIC Science & Technology

    2010-07-01

    Products HTBCT High Temperature Benchtop Corrosion Test HwFET Highway Fuel Economy Test IF Inorganic Fullerene JP-8 A kerosene based jet fuel lbs...engine crankcase lubricants at the request of TARDEC. This additive contains inorganic fullerene -like (IF) nano- particles of WS2 which were claimed...volume and hardness change are shown in Table 4 with MIL-PRF-46167D specified limits. Table 4: Seal Compatibility Test Results Material Property

  11. Airborne Nanostructured Particles and Occupational Health

    NASA Astrophysics Data System (ADS)

    Maynard, Andrew D.; Kuempel, Eileen D.

    2005-12-01

    Nanotechnology is leading to the development in many field, of new materials and devices in many fields that demonstrate nanostructure-dependent properties. However, concern has been expressed that these same properties may present unique challenges to addressing potential health impact. Airborne particles associated with engineered nanomaterials are of particular concern, as they can readily enter the body through inhalation. Research into the potential occupational health risks associated with inhaling engineered nanostructured particles is just beginning. However, there is a large body of data on occupational and environmental aerosols, which is applicable to developing an initial assessment of potential risk and risk reduction strategies. Epidemiological and pathological studies of occupational and environmental exposures to airborne particles and fibers provide information on the aerosol-related lung diseases and conditions that have been observed in humans. Toxicological studies provide information on the specific disease mechanisms, dose-response relationships, and the particle characteristics that influence toxicity, including the size, surface area, chemistry or reactivity, solubility, and shape. Potential health risk will depend on the magnitude and nature of exposures to airborne nanostructured particles, and on the release, dispersion, transformation and control of materials in the workplace. Aerosol control methods have not been well-characterized for nanometer diameter particles, although theory and limited experimental data indicate that conventional ventilation, engineering control and filtration approaches should be applicable in many situations. Current information supports the development of preliminary guiding principles on working with engineered nanomaterials. However critical research questions remain to be answered before the potential health risk of airborne nanostructured particles in the workplace can be fully addressed.

  12. 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

  13. Interface of physics and biology: engineering virus-based nanoparticles for biophotonics.

    PubMed

    Wen, Amy M; Infusino, Melissa; De Luca, Antonio; Kernan, Daniel L; Czapar, Anna E; Strangi, Giuseppe; Steinmetz, Nicole F

    2015-01-21

    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 due

  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. Soil-pore water distribution of silver and gold engineered nanoparticles in undisturbed soils under unsaturated conditions.

    PubMed

    Tavares, D S; Rodrigues, S M; Cruz, N; Carvalho, C; Teixeira, T; Carvalho, L; Duarte, A C; Trindade, T; Pereira, E; Römkens, P F A M

    2015-10-01

    Release of engineered nanoparticles (ENPs) to soil is well documented but little is known on the subsequent soil-pore water distribution of ENPs once present in soil. In this study, the availability and mobility of silver (Ag) and gold (Au) ENPs added to agricultural soils were assessed in two separate pot experiments. Pore water samples collected from pots from day 1 to 45 using porous (<0.17 μm) membrane samplers suggest that both Ag and Au are retained almost completely within 24 h with less than 13% of the total added amount present in pore water on day 1. UV-Vis and TEM results showed that AuENPs in pore water were present as both homoaggregates and heteroaggregates until day 3 after which the concentration in pore water was too low to detect the presence of aggregates. A close relation between the concentration of Au and Fe in pore water suggests that the short term solubility of Au is partly controlled by natural soil colloids. Results suggest that under normal aerated soil conditions the actual availability of Ag and AuENPs is low which is relevant in view of risk assessment even though the impact of environmental conditions and soil properties on the reactivity of ENPs (and/or large ENPs aggregates) retained in the solid matrix need to be addressed further.

  16. 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.

  17. 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.

  18. 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.

  19. Isotope Tracers To Study the Environmental Fate and Bioaccumulation of Metal-Containing Engineered Nanoparticles: Techniques and Applications.

    PubMed

    Yin, Yongguang; Tan, Zhiqiang; Hu, Ligang; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2017-03-08

    The rapidly growing applicability of metal-containing engineered nanoparticles (MENPs) has made their environmental fate, biouptake, and transformation important research topics. However, considering the relatively low concentration of MENPs and the high concentration of background metals in the environment and in organisms, tracking the fate of MENPs in environment-related scenarios remains a challenge. Intrinsic labeling of MENPs with radioactive or stable isotopes is a useful tool for the highly sensitive and selective detection of MENPs in the environment and organisms, thus enabling tracing of their transformation, uptake, distribution, and clearance. In this review, we focus on radioactive/stable isotope labeling of MENPs for their environmental and biological tracing. We summarize the advantages of intrinsic radioactive/stable isotopes for MENP labeling and discuss the considerations in labeling isotope selection and preparation of labeled MENPs, as well as exposure routes and detection of labeled MENPs. In addition, current practice in the use of radioactive/stable isotope labeling of MENPs to study their environmental fate and bioaccumulation is reviewed. Future perspectives and potential applications are also discussed, including imaging techniques for radioactive- and stable-isotope-labeled MENPs, hyphenated multistable isotope tracers with speciation analysis, and isotope fractionation as a MENP tracer. It is expected that this critical review could provide the necessary background information to further advance the applications of isotope tracers to study the environmental fate and bioaccumulation of MENPs.

  20. 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

  1. 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.

  2. 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.

  3. Review: Morphofunctional and biochemical markers of stress in sea urchin life stages exposed to engineered nanoparticles.

    PubMed

    Gambardella, Chiara; Ferrando, Sara; Gatti, Antonietta M; Cataldi, Edoardo; Ramoino, Paola; Aluigi, Maria Grazia; Faimali, Marco; Diaspro, Alberto; Falugi, Carla

    2016-11-01

    We describe the use of different life stages of the Mediterranean sea urchin Paracentrotus lividus for the assessment of the possible risk posed by nanoparticles (NPs) in the coastal water. A first screening for the presence of NPs in sea water may be obtained by checking their presence inside tissues of organisms taken from the wild. The ability of NPs to pass from gut to the coelomic fluid is demonstrated by accumulation in sea urchin coelomocytes; the toxicity on sperms can be measured by embryotoxicity markers after sperm exposure, whereas the transfer through the food chain can be observed by developmental anomalies in larvae fed with microalgae exposed to NPs. The most used spermiotoxicity and embryotoxicity tests are described, as well as the biochemical and histochemical analyses of cholinesterase (ChE) activities, which are used to verify toxicity parameters such as inflammation, neurotoxicity, and interference in cell-to-cell communication. Morphological markers of toxicity, in particular skeletal anomalies, are described and classified. In addition, NPs may impair viability of the immune cells of adult specimens. Molecular similarity between echinoderm and human immune cells is shown and discussed. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1552-1562, 2016.

  4. Engineering of Targeted Nanoparticles for Cancer Therapy Using Internalizing Aptamers Isolated by Cell-Uptake Selection

    PubMed Central

    Xiao, Zeyu; Levy-Nissenbaum, Etgar; Alexis, Frank; Lupták, Andrej; Teply, Benjamin A.; Chan, Juliana M.; Shi, Jinjun; Digga, Elise; Cheng, Judy; Langer, Robert; Farokhzad, Omid C.

    2012-01-01

    One of the major challenges in the development of targeted nanoparticles (NPs) for cancer therapy is to discover targeting ligands that allow for differential binding and uptake by the target cancer cells. Using prostate cancer (PCa) as a model disease, we developed a cell-uptake selection strategy to isolate PCa-specific internalizing 2'-Omethyl RNA aptamers (Apts) for NP incorporation. Twelve cycles of selection and counter-selection were done to obtain a panel of internalizing Apts, which can distinguish PCa cells from non-prostate and normal prostate cells. After Apt characterization, size minimization, and conjugation of the Apts with fluorescently-labeled polymeric NPs, the NP-Apt bioconjugates exhibit PCa specificity and enhancement in cellular uptake when compared to non-targeted NPs lacking the internalizing Apts. Furthermore, when docetaxel, a chemotherapeutic agent used for the treatment of PCa, was encapsulated within the NP-Apt, a significant improvement in cytotoxicity was achieved in targeted PCa cells. Rather than isolating high-affinity Apts as reported in previous selection processes, our selection strategy was designed to enrich cancer-cell specific internalizing Apts. A similar cell-uptake selection strategy may be used to develop specific internalizing ligands for a myriad of other diseases and can potentially facilitate delivering various molecules, including drugs and siRNAs, into cells. PMID:22214176

  5. 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

  6. Behavior and Potential Impacts of Metal-Based Engineered Nanoparticles in Aquatic Environments

    PubMed Central

    Peng, Cheng; Zhang, Wen; Gao, Haiping; Li, Yang; Tong, Xin; Li, Kungang; Zhu, Xiaoshan; Wang, Yixiang; Chen, Yongsheng

    2017-01-01

    The specific properties of metal-based nanoparticles (NPs) have not only led to rapidly increasing applications in various industrial and commercial products, but also caused environmental concerns due to the inevitable release of NPs and their unpredictable biological/ecological impacts. This review discusses the environmental behavior of metal-based NPs with an in-depth analysis of the mechanisms and kinetics. The focus is on knowledge gaps in the interaction of NPs with aquatic organisms, which can influence the fate, transport and toxicity of NPs in the aquatic environment. Aggregation transforms NPs into micrometer-sized clusters in the aqueous environment, whereas dissolution also alters the size distribution and surface reactivity of metal-based NPs. A unique toxicity mechanism of metal-based NPs is related to the generation of reactive oxygen species (ROS) and the subsequent ROS-induced oxidative stress. Furthermore, aggregation, dissolution and ROS generation could influence each other and also be influenced by many factors, including the sizes, shapes and surface charge of NPs, as well as the pH, ionic strength, natural organic matter and experimental conditions. Bioaccumulation of NPs in single organism species, such as aquatic plants, zooplankton, fish and benthos, is summarized and compared. Moreover, the trophic transfer and/or biomagnification of metal-based NPs in an aquatic ecosystem are discussed. In addition, genetic effects could result from direct or indirect interactions between DNA and NPs. Finally, several challenges facing us are put forward in the review. PMID:28336855

  7. 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

    2016-02-07

    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.

  8. 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.

  9. Tunable Conformation-Dependent Engineered Protein·Gold Nanoparticle Nanocomposites.

    PubMed

    Hume, Jasmin; Chen, Raymond; Jacquet, Rudy; Yang, Michael; Montclare, Jin Kim

    2015-06-08

    We demonstrate the fabrication of protein·gold nanoparticle (AuNP) nanocomposites in situ, leading to distinct assemblies dependent upon protein secondary structure. In the presence of pentameric coiled-coil proteins C and Q, which contain histidine tags and have helicities of 54 and 65%, respectively, templation of AuNP results in precipitation of the protein·AuNP composites with AuNPs 6.5 nm in diameter, creating macromolecular assemblies on the micrometer scale. In the absence of the histidine tags, the resulting Cx and Qx proteins, which exhibit lower helicities of 37 and 45%, respectively, stabilize soluble protein·AuNP composites with AuNPs 4.5 nm in diameter for several days without aggregating. By manipulating protein structure via external triggers, such as TFE, we obtain control over the macromolecular conformation and overall physicochemical properties. These hybrid protein·AuNP assemblies can be readily deposited on electrodes, where they can serve as a tunable bionanocomposite kinetic barrier.

  10. Cellular targets and mechanisms in the cytotoxic action of non-biodegradable engineered nanoparticles.

    PubMed

    Fröhlich, Eleonore

    2013-11-01

    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.

  11. Terahertz conductivity engineering in surface decorated carbon nanotube films by gold nanoparticles.

    PubMed

    Polley, Debanjan; Patra, Animesh; Barman, Anjan; Mitra, Rajib Kumar

    2017-02-01

    We report the controllable conductivity of single-walled carbon nanotubes (SWNTs) and multiwalled carbon nanotubes with their surface walls decorated by gold nanoparticles (Au NPs) with varying concentration in terahertz (THz) frequency range. Colloidal Au NPs of nominal diameter ∼15  nm are synthesized by the reduction of gold chloride solution using tri-sodium citrate. A simple chemical route is followed to attach Au NPs on the surfaces of both types of carbon nanotubes (CNTs). The attachment of Au NPs on the sidewalls of CNTs is confirmed by UV-visible spectroscopy and scanning electron microscope images. THz spectroscopic measurements are carried out at room temperature in transmission geometry in the frequency range of 0.3-2.0 THz. It is found that the THz conductivity of the surface decorated SWNT composites can either be increased or decreased by ±15% than that of the as-prepared SWNT composites by carefully choosing the Au NP concentration. The conductivity variation is qualitatively explained in terms of carrier trapping potential for low Au NP density, and alternative carrier conduction pathways at higher Au NP density and analyzed with the help of a modified universal dielectric relaxation model.

  12. Transport and retention of selected engineered nanoparticles by porous media in the presence of a biofilm.

    PubMed

    Xiao, Yao; Wiesner, Mark R

    2013-03-05

    Column experiments were conducted to investigate the transport of aqueous C60 (aqu-nC60), fullerol, silver nanoparticles (NPs) coated with polyvinylpyrrolidone (Ag-PVP) and stabilized by citrate (Ag-CIT) in biofilm-laden porous media. Gram-negative Pseudomonas aeruginosa (PA) and Gram-positive Bacillus cereus (BC) biofilm-laden glass beads were selected to represent the bacterial interfaces NPs might encounter in the natural aquatic environment. The biomass distribution, extracellular polymeric substances (EPS) components, electrokinetic property, and hydrophobicity of these interfaces were characterized, and the hydrophobicity was found to correlate with the quantity of proteins in EPS. The retention of NPs on glass beads coated with bovine serum albumin (BSA) and alginate were also studied. Except for Ag-PVP, the affinity of NPs for porous medium, indicated by attachment efficiency α, increased in the presence of biofilms, BSA and alginate. For hydrophobic aqu-nC60, the larger the proteins/polysaccharides ratio, the larger the α, suggesting the hydrophobic interaction determines the attachment of aqu-nC60 to the collector surface. Uncharged PVP stabilized Ag-PVP by steric repulsion, and the attachment to glass beads was not enhanced by biofilm. The presence of divalent ion Ca(2+) significantly hydrophobized biofilm, BSA, and alginate-coated glass beads and further retarded the mobility of aqu-nC60, fullerol, and Ag-CIT; while Ag-PVP was again sterically stabilized.

  13. 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.

  14. Comparison of Airborne Electromagnetic Induction and Subsurface Radar Sounding of Freshwater Bathymetry

    DTIC Science & Technology

    1993-05-01

    AD-A268 703 Comparison of Airborne * Electromagnetic Induction and Subsurface Radar Sounding of Freshwater Bathymetry Austin Kovacs and J , Scott Holladay...Laboratory Comparison of Airborne Electromagnefic Induction and Subsurface Radar Sounding of Freshwater Bcdhymetry Austin Kovacs and J . Scott Holladay May 1993...Engineer, of the Applied Research Branch, Experimental Engineering Division, U.S. Army Cold Regions Research and Engineering Laboratory, and J . Scott Holladay

  15. Airborne Next: Rethinking Airborne Organization and Applying New Concepts

    DTIC Science & Technology

    2015-06-01

    structures since its employment on a large scale during World War II. It is puzzling to consider how little airborne organizational structures and employment...future potential of airborne concepts by rethinking traditional airborne organizational structures and employment concepts. Using a holistic approach in... structures of airborne forces to model a “small and many” approach over a “large and few” approach, while incorporating a “swarming” concept. Utilizing

  16. Engineering of blended nanoparticle platform for delivery of mitochondria-acting therapeutics.

    PubMed

    Marrache, Sean; Dhar, Shanta

    2012-10-02

    Mitochondrial dysfunctions cause numerous human disorders. A platform technology based on biodegradable polymers for carrying bioactive molecules to the mitochondrial matrix could be of enormous potential benefit in treating mitochondrial diseases. Here we report a rationally designed mitochondria-targeted polymeric nanoparticle (NP) system and its optimization for efficient delivery of various mitochondria-acting therapeutics by blending a targeted poly(d,l-lactic-co-glycolic acid)-block (PLGA-b)-poly(ethylene glycol) (PEG)-triphenylphosphonium (TPP) polymer (PLGA-b-PEG-TPP) with either nontargeted PLGA-b-PEG-OH or PLGA-COOH. An optimized formulation was identified through in vitro screening of a library of charge- and size-varied NPs, and mitochondrial uptake was studied by qualitative and quantitative investigations of cytosolic and mitochondrial fractions of cells treated with blended NPs composed of PLGA-b-PEG-TPP and a triblock copolymer containing a fluorescent quantum dot, PLGA-b-PEG-QD. The versatility of this platform was demonstrated by studying various mitochondria-acting therapeutics for different applications, including the mitochondria-targeting chemotherapeutics lonidamine and α-tocopheryl succinate for cancer, the mitochondrial antioxidant curcumin for Alzheimer's disease, and the mitochondrial uncoupler 2,4-dinitrophenol for obesity. These biomolecules were loaded into blended NPs with high loading efficiencies. Considering efficacy, the targeted PLGA-b-PEG-TPP NP provides a remarkable improvement in the drug therapeutic index for cancer, Alzheimer's disease, and obesity compared with the nontargeted construct or the therapeutics in their free form. This work represents the potential of a single, programmable NP platform for the diagnosis and targeted delivery of therapeutics for mitochondrial dysfunction-related diseases.

  17. 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.

  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. 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

  20. Quantitatively probing propensity for structural transitions in engineered virus nanoparticles by single-molecule mechanical analysis.

    PubMed

    Castellanos, Milagros; Carrillo, Pablo J P; Mateu, Mauricio G

    2015-03-19

    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.

  1. Size engineering of metal nanoparticles to diameter-specified growth of single-walled carbon nanotubes with horizontal alignment on quartz

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Ju; Lee, Byeong-Joo; Lee, Seung-Hwan; Jeong, Goo-Hwan

    2012-03-01

    The electronic, physical and optical properties of single-walled carbon nanotubes (SWNTs) are governed by their diameter and chirality, and thus much research has been focused on controlling the diameter and chirality of SWNTs. To date, control of the catalyst particle size has been thought to be one of the most promising approaches to control the diameter or chirality of SWNTs owing to the correlation between catalyst particle size and tube diameter. In this study, we demonstrate the size engineering of catalytic nanoparticles for the controlled growth of diameter-specified and horizontally aligned SWNTs on quartz substrates. Uniformly sized iron nanoparticles derived from ferritin molecules were used as a catalyst, and their size was intentionally decreased via thermal heat treatment at 900 °C under atmospheric Ar ambient. ST-cut quartz wafers were used as growth substrates in order to elucidate the effect of the size of the nanoparticles on the tube diameter and the effect of catalyst size on the degree of parallel alignment on the quartz substrates. SWNTs grown by chemical vapor deposition using methane as feedstock exhibited a high degree of horizontal alignment when the particle density was low enough to produce individual SWNTs without bundling. Annealing for 60 min at 900 °C produced a reduction of nanoparticle diameter from 2.6 to 1.8 nm and a decrease in the mean tube diameter from 1.2 to 0.8 nm, respectively. Raman spectroscopy results corroborated the observation that prolonged heat treatment of nanoparticles yields thinner tubes with narrower size distributions. The results of this work suggest that straightforward thermal annealing can be a facile way to obtain uniform-sized SWNTs as well as catalytic nanoparticles.

  2. Adipose tissue engineering in three-dimensional levitation tissue culture system based on magnetic nanoparticles.

    PubMed

    Daquinag, Alexes C; Souza, Glauco R; Kolonin, Mikhail G

    2013-05-01

    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

  3. Modeling In Vivo Interactions of Engineered Nanoparticles in the Pulmonary Alveolar Lining Fluid.

    PubMed

    Mukherjee, Dwaipayan; Porter, Alexandra; Ryan, Mary; Schwander, Stephan; Chung, Kian Fan; Tetley, Teresa; Zhang, Junfeng; Georgopoulos, Panos

    2015-09-01

    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.

  4. 30 CFR 57.5005 - Control of exposure to airborne contaminants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Control of exposure to airborne contaminants... Underground § 57.5005 Control of exposure to airborne contaminants. Control of employee exposure to harmful... ventilation, or by dilution with uncontaminated air. However, where accepted engineering control measures...

  5. 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.

  6. Developmental abnormalities and changes in cholinesterase activity in sea urchin embryos and larvae from sperm exposed to engineered nanoparticles.

    PubMed

    Gambardella, Chiara; Aluigi, Maria G; Ferrando, Sara; Gallus, Lorenzo; Ramoino, Paola; Gatti, Antonietta M; Rottigni, Marino; Falugi, Carla

    2013-04-15

    The objective of this study is to examine the toxicity of engineered nanoparticles (NPs) that are dispersed in sea water by using an in vivo model. Because many products of nanotechnology contain NPs and are commonly used and well-established in the market, the accidental release of NPs into the air and water is quite possible. Indeed, at the end of their life cycle, some NPs are inevitably released into waste water and can reach marine ecosystem and affect the organisms there. Although there are few data on the presence of NPs in the marine environment, our awareness of their potential impact on environmental and organismal health is growing. Shallow-water benthonic organisms such as sea urchins provide planktonic larvae as a trophic base for finfish juveniles and are exposed to water from estuaries and precipitation. Such organisms can therefore be directly affected by NPs that are dispersed into those media. We evaluated the effects of exposure to different concentrations of nanosilver, titanium oxide and cobalt NPs on the sperm of the sea urchin Paracentrotus lividus by analyzing the functionality and the morphology and biochemistry of the first developmental stages of the sea urchin. Sperm were exposed to sea water containing suspensions of NPs ranging from 0.0001 mg/L to 1 mg/L. Fertilization ability was not affected, but developmental anomalies were identified in embryos from the gastrula to pluteus stages, including morphological alterations of the skeletal rods. In addition, the enzymatic activity (cholinesterase, ChE) of the larvae was measured. Acetylcholinesterase (AChE) and propionylcholinesterase activity (PrChE) was affected in all of the exposed samples. The results did not vary consistently with the concentration of NP, but controls were significantly different from exposed samples. Exposure of sea urchin to these NPs may cause neurotoxic damage, and the altered ChE activity may be involved in skeletogenic aberrations. In conclusion, the sea urchin

  7. Transformation of Cerium Oxide Nanoparticles from a Diesel Fuel Additive during Combustion in a Diesel Engine.

    PubMed

    Dale, James G; Cox, Steven S; Vance, Marina E; Marr, Linsey C; Hochella, Michael F

    2017-02-21

    Nanoscale cerium oxide is used as a diesel fuel additive to reduce particulate matter emissions and increase fuel economy, but its fate in the environment has not been established. Cerium oxide released as a result of the combustion of diesel fuel containing the additive Envirox, which utilizes suspended nanoscale cerium oxide to reduce particulate matter emissions and increase fuel economy, was captured from the exhaust stream of a diesel engine and was characterized using a combination of bulk analytical techniques and high resolution transmission electron microscopy. The combustion process induced significant changes in the size and morphology of the particles; ∼15 nm aggregates consisting of 5-7 nm faceted crystals in the fuel additive became 50-300 nm, near-spherical, single crystals in the exhaust. Electron diffraction identified the original cerium oxide particles as cerium(IV) oxide (CeO2, standard FCC structure) with no detectable quantities of Ce(III), whereas in the exhaust the ceria particles had additional electron diffraction reflections indicative of a CeO2 superstructure containing ordered oxygen vacancies. The surfactant coating present on the cerium oxide particles in the additive was lost during combustion, but in roughly 30% of the observed particles in the exhaust, a new surface coating formed, approximately 2-5 nm thick. The results of this study suggest that pristine, laboratory-produced, nanoscale cerium oxide is not a good substitute for the cerium oxide released from fuel-borne catalyst applications and that future toxicity experiments and modeling will require the use/consideration of more realistic materials.

  8. 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.

  9. 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.

  10. 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)

  11. Airborne asbestos in buildings.

    PubMed

    Lee, R J; Van Orden, D R

    2008-03-01

    The concentration of airborne asbestos in buildings nationwide is reported in this study. A total of 3978 indoor samples from 752 buildings, representing nearly 32 man-years of sampling, have been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result the presence of asbestos-containing materials (ACM). The average concentration of all airborne asbestos structures was 0.01structures/ml (s/ml) and the average concentration of airborne asbestos > or = 5microm long was 0.00012fibers/ml (f/ml). For all samples, 99.9% of the samples were <0.01 f/ml for fibers longer than 5microm; no building averaged above 0.004f/ml for fibers longer than 5microm. No asbestos was detected in 27% of the buildings and in 90% of the buildings no asbestos was detected that would have been seen optically (> or = 5microm long and > or = 0.25microm wide). Background outdoor concentrations have been reported at 0.0003f/ml > or = 5microm. These results indicate that in-place ACM does not result in elevated airborne asbestos in building atmospheres approaching regulatory levels and that it does not result in a significantly increased risk to building occupants.

  12. Magnetically labeled cells with surface-modified fe3 o4 spherical and rod-shaped magnetic nanoparticles for tissue engineering applications.

    PubMed

    Gil, Sara; Correia, Clara R; Mano, João F

    2015-04-22

    Magnetically targeted cells with internalized magnetic nanoparticles (MNPs) could allow the success of cell transplantation and cell-based therapies, overcoming low cell retention that occurs when delivering cells by intravenous or local injection. Upon magnetization, these cells could then accumulate and stimulate the regeneration of the tissue in situ. Magnetic targeting of cells requires a detailed knowledge between interactions of engineered nanomaterials and cells, in particular the influence of shape and surface functionalization of MNPs. For the first time, cellular internalization of amino surface-modified iron oxide nanoparticles of two different shapes (nanospheres or nanorods) is studied. MNPs show high cellular uptake and labeled cells could exhibit a strong reaction with external magnetic fields. Compared to nanorods, nanospheres show better internalization efficiency, and labeled cells exhibit strong transportation reaction with external magnetic fields. Contiguous viable cell-sheets are developed by magnetic-force-based tissue engineering. The results confirm that the developed magnetic-responsive nano-biomaterials have potential applicability in tissue engineering or cellular therapies.

  13. Photoreactivation in Airborne Mycobacterium parafortuitum

    PubMed Central

    Peccia, Jordan; Hernandez, Mark

    2001-01-01

    Photoreactivation was observed in airborne Mycobacterium parafortuitum exposed concurrently to UV radiation (254 nm) and visible light. Photoreactivation rates of airborne cells increased with increasing relative humidity (RH) and decreased with increasing UV dose. Under a constant UV dose with visible light absent, the UV inactivation rate of airborne M. parafortuitum cells decreased by a factor of 4 as RH increased from 40 to 95%; however, under identical conditions with visible light present, the UV inactivation rate of airborne cells decreased only by a factor of 2. When irradiated in the absence of visible light, cellular cyclobutane thymine dimer content of UV-irradiated airborne M. parafortuitum and Serratia marcescens increased in response to RH increases. Results suggest that, unlike in waterborne bacteria, cyclobutane thymine dimers are not the most significant form of UV-induced DNA damage incurred by airborne bacteria and that the distribution of DNA photoproducts incorporated into UV-irradiated airborne cells is a function of RH. PMID:11526027

  14. Airborne Laser/GPS Mapping of Beaches

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Swift, R. N.; Fredrick, E. B.; Manizade, S. S.; Martin, C. F.; Sonntag, J. G.; Duffy, Mark

    1999-01-01

    Results are presented from topographic surveys of the Assateague National Seashore Park using recently developed airborne laser and Global Positioning System (GPS) technology. During November, 1995, and again in May, 1996, the NASA Arctic Ice Mapping (AIM) group from the NASA Goddard Space Flight Center's Wallops Flight Facility conducted surveys as a part of technology enhancement activities or warm-up missions prior to conducting elevation measurements of the Greenland Ice Sheet as part of NASA's Global Climate Change program. The resulting data are compared to surface surveys using standard techniques. The goal of these projects is to make these measurements to an accuracy of 10 cm. The measurements were made from NASA's 4-engine P-3 Orion aircraft using the Airborne Topographic Mapper (ATM), a scanning laser system. The necessary high accuracy vertical as well as horizontal positioning are provided by Global Positioning System (GPS) receivers located both on board the aircraft and at a fixed site at Wallops Island.

  15. 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 ...

  16. 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

  17. 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.

  18. Absolute airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Baumann, Henri

    This work consists of a feasibility study of a first stage prototype airborne absolute gravimeter system. In contrast to relative systems, which are using spring gravimeters, the measurements acquired by absolute systems are uncorrelated and the instrument is not suffering from problems like instrumental drift, frequency response of the spring and possible variation of the calibration factor. The major problem we had to resolve were to reduce the influence of the non-gravitational accelerations included in the measurements. We studied two different approaches to resolve it: direct mechanical filtering, and post-processing digital compensation. The first part of the work describes in detail the different mechanical passive filters of vibrations, which were studied and tested in the laboratory and later in a small truck in movement. For these tests as well as for the airborne measurements an absolute gravimeter FG5-L from Micro-G Ltd was used together with an Inertial navigation system Litton-200, a vertical accelerometer EpiSensor, and GPS receivers for positioning. These tests showed that only the use of an optical table gives acceptable results. However, it is unable to compensate for the effects of the accelerations of the drag free chamber. The second part describes the strategy of the data processing. It is based on modeling the perturbing accelerations by means of GPS, EpiSensor and INS data. In the third part the airborne experiment is described in detail, from the mounting in the aircraft and data processing to the different problems encountered during the evaluation of the quality and accuracy of the results. In the part of data processing the different steps conducted from the raw apparent gravity data and the trajectories to the estimation of the true gravity are explained. A comparison between the estimated airborne data and those obtained by ground upward continuation at flight altitude allows to state that airborne absolute gravimetry is feasible and

  19. 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

  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. The ultimate step towards a tailored engineering of core@shell and core@shell@shell nanoparticles.

    PubMed

    Llamosa, D; Ruano, M; Martínez, L; Mayoral, A; Roman, E; García-Hernández, M; Huttel, Y

    2014-11-21

    Complex core@shell and core@shell@shell nanoparticles are systems that combine the functionalities of the inner core and outer shell materials together with new physico-chemical properties originated by their low (nano) dimensionality. Such nanoparticles are of prime importance in the fast growing field of nanotechnology as building blocks for more sophisticated systems and a plethora of applications. Here, it is shown that although conceptually simple a modified gas aggregation approach allows the one-step generation of well-controlled complex nanoparticles. In particular, it is demonstrated that the atoms of the core and the shell of the nanoparticles can be easily inverted, avoiding intrinsic constraints of chemical methods.

  2. 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.

  3. 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.

  4. Airborne Intercept Monitoring

    DTIC Science & Technology

    2006-04-01

    Primary mirror of Zerodur with Pilkington 747 coating • FOV = 0.104 degrees Airborne Intercept Monitoring RTO-MP-SET-105 16 - 3 UNCLASSIFIED...Pointing System (SPS). The STS is a 0.75 meter aperture Mersenne Cassegrain telescope and the SAT is a 0.34 meter aperture 3- mirror anastigmat telescope...UNLIMITED UNCLASSIFIED/UNLIMITED • Air Flow to Mitigate Thermal “Seeing” Effects • Light weighted primary mirror to reduce mass The SAT

  5. 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.

  6. Airborne Infrared Astronomical Telescopes

    NASA Astrophysics Data System (ADS)

    Erickson, Edwin F.

    2017-01-01

    A unique program of infrared astronomical observations from aircraft evolved at NASA’s Ames Research Center, beginning in the 1960s. Telescopes were flown on a Convair 990, a Lear Jet, and a Lockheed C-141 - the Kuiper Airborne Observatory (KAO) - leading to the planning and development of SOFIA: a 2.7 m telescope now flying on a Boeing 747SP. The poster describes these telescopes and highlights of some of the scientific results obtained from them.

  7. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D [Menan, ID; Schmitt, Michael J [Idaho Falls, ID; Jones, Warren F [Idaho Falls, ID

    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.

  8. 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.

  9. 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

  10. 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 ...

  11. Changing the dose metric for inhalation toxicity studies: short-term study in rats with engineered aerosolized amorphous silica nanoparticles.

    PubMed

    Sayes, Christie M; Reed, Kenneth L; Glover, Kyle P; Swain, Keith A; Ostraat, Michele L; Donner, E Maria; Warheit, David B

    2010-03-01

    Inhalation toxicity and exposure assessment studies for nonfibrous particulates have traditionally been conducted using particle mass measurements as the preferred dose metric (i.e., mg or microg/m(3)). However, currently there is a debate regarding the appropriate dose metric for nanoparticle exposure assessment studies in the workplace. The objectives of this study were to characterize aerosol exposures and toxicity in rats of freshly generated amorphous silica (AS) nanoparticles using particle number dose metrics (3.7 x 10(7) or 1.8 x 10(8) particles/cm(3)) for 1- or 3-day exposures. In addition, the role of particle size (d(50) = 37 or 83 nm) on pulmonary toxicity and genotoxicity endpoints was assessed at several postexposure time points. A nanoparticle reactor capable of producing, de novo synthesized, aerosolized amorphous silica nanoparticles for inhalation toxicity studies was developed for this study. SiO(2) aerosol nanoparticle synthesis occurred via thermal decomposition of tetraethylorthosilicate (TEOS). The reactor was designed to produce aerosolized nanoparticles at two different particle size ranges, namely d(50) = approximately 30 nm and d(50) = approximately 80 nm; at particle concentrations ranging from 10(7) to 10(8) particles/cm(3). AS particle aerosol concentrations were consistently generated by the reactor. One- or 3-day aerosol exposures produced no significant pulmonary inflammatory, genotoxic, or adverse lung histopathological effects in rats exposed to very high particle numbers corresponding to a range of mass concentrations (1.8 or 86 mg/m(3)). Although the present study was a short-term effort, the methodology described herein can be utilized for longer-term inhalation toxicity studies in rats such as 28-day or 90-day studies. The expansion of the concept to subchronic studies is practical, due, in part, to the consistency of the nanoparticle generation method.

  12. 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.

  13. 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.

  14. DC-8 Airborne Laboratory in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This 17-second clip shows air-to-air shots of the NASA DC-8 airborne laboratory as it passes over the NASA Dryden Flight Research Center at Edwards, California, and the foothills of the Sierra Nevada mountains. On December 29, 1997, NASA Dryden Flight Research Center, Edwards, California, received a DC-8 airborne laboratory from NASA Ames Research Center, Moffett Field, California, where it had flown missions related to airborne science and earth science for many years. This airplane has continued to be used from Dryden for basic research about the Earth's surface and atmosphere as well as sensor development and satellite sensor verification. In mid-February 1998, the DC-8 resumed flying its medium-altitude, science-gathering missions following maintenance and upgrades of its satellite communications system. It flew a variety of missions over widely scattered geographic regions during the rest of the calendar year and beyond to gather data about earth science, including weather and climate. Built by Douglas Aircraft Company, Long Beach, California, in 1966, the DC-8 flew for 20 years with two major airlines before being acquired by NASA and converted to its present role as an airborne laboratory. The four-engine former jetliner was capable of flying extended-duration missions as long as 12 hours over a range of 5,400 nautical miles at cruise altitudes up to 41,000 feet. It was also capable of carrying a payload of multiple experiments weighing up to 30,000 pounds. On some of its missions, up to 30 scientists have worked on as many as 14 different experiments.

  15. DC-8 airborne laboratory in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this 26-second clip the NASA DC-8 airborne laboratory is shown making turns over the Sierra Nevada foothills, NASA Dryden Flight Research Center, and Rogers Dry Lakebed at Edwards Air Force Base, California. On December 29, 1997, NASA Dryden Flight Research Center, Edwards, California, received a DC-8 airborne laboratory from NASA Ames Research Center, Moffett Field, California, where it had flown missions related to airborne science and earth science for many years. This airplane has continued to be used from Dryden for basic research about the Earth's surface and atmosphere as well as sensor development and satellite sensor verification. In mid-February 1998, the DC-8 resumed flying its medium-altitude, science-gathering missions following maintenance and upgrades of its satellite communications system. It flew a variety of missions over widely scattered geographic regions during the rest of the calendar year and beyond to gather data about earth science, including weather and climate. Built by Douglas Aircraft Company, Long Beach, California, in 1966, the DC-8 flew for 20 years with two major Airlines before being acquired by NASA and converted to its present role as an airborne laboratory. The four-engine former jetliner was capable of flying extended-duration missions for as long as 12 hours over a range of 5,400 nautical miles at cruise altitudes of up to 41,000 feet. It was also capable of carrying a payload of multiple experiments weighing up to 30,000 pounds. On some of its missions, up to 30 scientists have worked on as many as 14 different experiments.

  16. 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.

  17. 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.

  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. The New Airborne Disease

    PubMed Central

    Goldsmith, John R.

    1970-01-01

    Community air pollution is the new airborne disease of our generation's communities. It is caused by the increasing use of fuel, associated with both affluence and careless waste. Photochemical air pollution of the California type involves newly defined atmospheric reactions, is due mostly to motor vehicle exhaust, is oxidizing, and produces ozone, plant damage, impairment of visibility and eye and respiratory symptoms. Aggravation of asthma, impairment of lung function among persons with chronic respiratory disease and a possible causal role, along with cigarette smoking in emphysema and chronic bronchitis, are some of the effects of photochemical pollution. More subtle effects of pollution include impairment of oxygen transport by the blood due to carbon monoxide and interference with porphyrin metabolism due to lead. Carbon monoxide exposures may affect survival of patients who are in hospitals because of myocardial infarction. While many uncertainties in pollution-health reactions need to be resolved, a large number of people in California have health impairment due to airborne disease of this new type. PMID:5485227

  20. Airborne transmission of disease in hospitals

    PubMed Central

    Eames, I.; Tang, J. W.; Li, Y.; Wilson, P.

    2009-01-01

    Hospital-acquired infection (HAI) is an important public health issue with unacceptable levels of morbidity and mortality, over the last 5 years. Disease can be transmitted by air (over large distances), by direct/indirect contact or a combination of both routes. While contact transmission of disease forms the majority of HAI cases, transmission through the air is harder to control, but one where the engineering sciences can play an important role in limiting the spread. This forms the focus of this themed volume. In this paper, we describe the current hospital environment and review the contributions from microbiologists, mechanical and civil engineers, and mathematicians to this themed volume on the airborne transmission of infection in hospitals. The review also points out some of the outstanding scientific questions and possible approaches to mitigating transmission. PMID:19828499

  1. Effects of Cerium Oxide and Ferrocene Nanoparticles Addition As Fuel-Borne Catalysts on Diesel Engine Particulate Emissions: Environmental and Health Implications.

    PubMed

    Zhang, Zhi-Hui; Balasubramanian, Rajasekhar

    2017-04-06

    This study systematically examined the potential impacts of doping CeO2 and Fe(C5H5)2 nanoparticles as fuel-borne catalysts (FBCs) to ultralow sulfur diesel (ULSD) fuel on the physical, chemical and toxicological characteristics of diesel particulate matter (DPM). The FBCs-doped fuels are effective in promoting soot oxidation and reducing the DPM mass emissions, but lead to a significant increase in the total particle counts due to the formation of self-nucleated metallic nanoparticles. Compared to undoped ULSD, the FBCs-doped fuels result in higher concentrations of particle-phase polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, higher fractions of organic carbon (OC) and water-soluble organic carbon (WSOC) in particles, show slight alterations in soot nanostructure, reduce soot ignition temperature and activation energy. Exposure of the human-type II cell alveolar epithelial cells (A549) to DPM derived from FBCs-doped fuels shows a decrease in cell viability and alterations in the global gene expression with a broad range of biochemical pathways. The overall variations in DPM characteristics are mainly caused by the catalytic combustion process, and are related to the type, properties and contents of FBCs used in diesel fuel as well as the engine operating conditions. Environmental and health implications of the study are highlighted.

  2. 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...

  3. Airborne Emissions from Si/FeSi Production

    NASA Astrophysics Data System (ADS)

    Kero, Ida; Grådahl, Svend; Tranell, Gabriella

    2017-02-01

    The management of airborne emissions from silicon and ferrosilicon production is, in many ways, similar to the management of airborne emissions from other metallurgical industries, but certain challenges are highly branch-specific, for example the dust types generated and the management of NO X emissions by furnace design and operation. A major difficulty in the mission to reduce emissions is that information about emission types and sources as well as abatement and measurement methods is often scarce, incomplete and scattered. The sheer diversity and complexity of the subject presents a hurdle, especially for new professionals in the field. This article focuses on the airborne emissions from Si and FeSi production, including greenhouse gases, nitrogen oxides, airborne particulate matter also known as dust, polyaromatic hydrocarbons and heavy metals. The aim is to summarize current knowledge in a state-of-the-art overview intended to introduce fresh industry engineers and academic researchers to the technological aspects relevant to the reduction of airborne emissions.

  4. The role of atmospheric transformations in determining environmental impacts of carbonaceous nanoparticles.

    PubMed

    Tiwari, Andrea J; Marr, Linsey C

    2010-01-01

    In studies that have explored the potential environmental impacts of manufactured nanomaterials, the atmosphere has largely been viewed as an inert setting that acts merely as a route for inhalation exposure. Manufactured nanomaterials will enter the atmosphere during production, use, and disposal, and rather than simply being transported, airborne nanoparticles are in fact subject to physical and chemical transformations that could modify their fate, transport, bioavailability, and toxicity once they deposit to aqueous and terrestrial ecosystems. The objective of this paper is to review the factors affecting carbonaceous nanomaterials' behavior in the environment and to show that atmospheric transformations, often overlooked, have the potential to alter nanoparticles' physical and chemical properties and thus influence their environmental fate and impact. Atmospheric processing of naturally occurring and incidental nanoparticles takes place through coagulation, condensation, and oxidation; these phenomena are expected to affect manufactured nanoparticles as well. It is likely that carbonaceous nanomaterials in the atmosphere will be oxidized, effectively functionalizing them. By influencing size, shape, and surface chemistry, atmospheric transformations have the potential to affect a variety of nanoparticle-environment interactions, including solubility, interaction with natural surfactants, deposition to porous media, and ecotoxicity. Potential directions for future research are suggested to address the current lack of information surrounding atmospheric transformations of engineered nanomaterials.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Size distributions of aerosols in an indoor environment with engineered nanoparticle synthesis reactors operating under different scenarios

    NASA Astrophysics Data System (ADS)

    Sahu, Manoranjan; Biswas, Pratim

    2010-03-01

    Size distributions of nanoparticles in the vicinity of synthesis reactors will provide guidelines for safe operation and protection of workers. Nanoparticle concentrations and size distributions were measured in a research academic laboratory environment with two different types of gas-phase synthesis reactors under a variety of operating conditions. The variation of total particle number concentration and size distribution at different distances from the reactor, off-design state of the fume hood, powder handling during recovery, and maintenance of reactors are established. Significant increases in number concentration were observed at all the locations during off-design conditions (i.e., failure of the exhaust system). Clearance of nanoparticles from the work environment was longer under off-design conditions (20 min) compared to that under normal hood operating conditions (4-6 min). While lower particle number concentrations are observed during operation of furnace aerosol reactors in comparison to flame aerosol reactors, the handling, processing, and maintenance operations result in elevated concentrations in the work area.

  10. Electrospun Poly(L-Lactic Acid)-co-Poly(ϵ-Caprolactone) Nanofibres Containing Silver Nanoparticles for Skin-Tissue Engineering.

    PubMed

    Jin, Guorui; Prabhakaran, Molamma P; Nadappuram, Binoy P; Singh, Gurdev; Kai, Dan; Ramakrishna, Seeram

    2012-01-01

    Silver nanoparticles (AgNPs) and silver ions (Ag(+)) show growth-inhibitory activity against microorganisms and have been used for decades as antibacterial agents in various fields. To fabricate a nanofibrous scaffold which is antibacterial against bacteria and non-toxic to cells, we electrospun composite poly(L-lactic acid)-co-poly(ϵ-caprolactone) nanofibres containing silver nanoparticles (PLLCL-AgNPs) with different concentrations (0.25, 0.50 and 0.75 wt%) of silver nitrate (AgNO3) in PLLCL. The diameters of the electrospun PLLCL-AgNPs nanofibres decreased with the increase of AgNO3 concentration in PLLCL solutions. Human skin fibroblasts cultured on the scaffolds showed that the PLLCL nanofibres containing lesser amounts of AgNPs (0.25 wt%) had better cell proliferation and retained the cell morphology similar to the phenotype observed on tissue culture plates (control). The antibacterial activity of AgNPs in PLLCL nanofibres was investigated against Staphylococcus aureus and Salmonella enterica and the antimicrobial activity was found to increase with the increasing concentration of nanoparticles present in the scaffold. Based on our studies, we propose that PLLCL nanofibres containing 0.25 wt% AgNO3 or PLLCL-Ag(25), favors cell proliferation and inhibits bacteria and could be a suitable substrate for wound healing.

  11. 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.

  12. 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.

  13. 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.

  14. 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

    2015-09-16

    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.

  15. 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.

  16. Facial Layer-by-Layer Engineering of Upconversion Nanoparticles for Gene Delivery: Near-Infrared-Initiated Fluorescence Resonance Energy Transfer Tracking and Overcoming Drug Resistance in Ovarian Cancer.

    PubMed

    Lin, Min; Gao, Yan; Diefenbach, Thomas J; Shen, Jacson K; Hornicek, Francis J; Park, Yong Il; Xu, Feng; Lu, Tian Jian; Amiji, Mansoor; Duan, Zhenfeng

    2017-03-08

    Development of multidrug resistance (MDR) contributes to the majority of treatment failures in clinical chemotherapy. We report facial layer-by-layer engineered upconversion nanoparticles (UCNPs) for near-infrared (NIR)-initiated tracking and delivery of small interfering RNA (siRNA) to enhance chemotherapy efficacy by silencing the MDR1 gene and resensitizing resistant ovarian cancer cells to drug. Layer-by-layer engineered UCNPs were loaded with MDR1 gene-silencing siRNA (MDR1-siRNA) by electrostatic interaction. The delivery vehicle enhances MDR1-siRNA cellular uptake, protects MDR1-siRNA from nuclease degradation, and promotes endosomal escape for silencing the MDR gene. The intrinsic photon upconversion of UCNPs provides an unprecedented opportunity for monitoring intracellular attachment and release of MDR1-siRNA by NIR-initiated fluorescence resonance energy transfer occurs between donor UCNPs and acceptor fluorescence dye-labeled MDR1-siRNA. Enhanced chemotherapeutic efficacy in vitro was demonstrated by cell viability assay. The developed delivery vehicle holds great potential in delivery and imaging-guided tracking of therapeutic gene targets for effective treatment of drug-resistant cancers.

  17. 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

  18. Technical basis for removal of 221-T tunnel from airborne radiological area status

    SciTech Connect

    Geuther, W.J., Westinghouse Hanford

    1996-08-30

    This document provides the technical basis for removal of the 221-T Tunnel from airborne radiological control. T Plant Radiological Control has evaluated air sampling data and engineering controls, and determined the necessary administrative controls to make this transition. With these administrative controls (specified within document) in place, the tunnel can be removed from Airborne Radioactive Area status. The removal of the tunnel from airborne status will allow work to be performed within the tunnel under controlled conditions, as outlined in this technical basis, without the use of respiratory protection equipment.

  19. An Introduction to Coastal Zone Mapping With Airborne Lidar: The Shoals System

    DTIC Science & Technology

    2000-01-01

    AN INTRODUCTION TO COASTAL ZONE MAPPING WITH AIRBORNE LIDAR : THE SHOALS SYSTEM Jennifer L. Irish US Army Engineer Research and Development...Center Coastal and Hydraulics Laboratory Joint Airborne Lidar Bathymetry Technical Center of Expertise 109 St. Joseph Street, Mobile, AL 36602-3630...USA http://shoals.sam.usace.army.mil ABSTRACT Recent advancements in lidar sensors now allow for near-synoptic, regional-scale mapping of the

  20. The use of airborne geophysics for levee classification and assessment

    NASA Astrophysics Data System (ADS)

    Dunbar, Joseph B.

    2011-12-01

    This research is the first known application into using airborne geophysical methods to evaluate and classify levees. This research is an important step toward developing new technologies and methods to rapidly screen and evaluate earthen flood control levees for safety against flooding. An investigation of airborne geophysical methods was conducted on levees in the lower Rio Grande Valley and involved electromagnetic induction, magnetometer, and LiDAR surveys of the levee system. Airborne EM signatures were analyzed by geologic mapping of floodplain depositional environments, examination of published soils data, and drilling of borings. A geographic information system was developed to manage the various data sets and evaluate historic land use changes and development of the flood control systems to better understand the signatures using airborne methods. This research presents information about the historic basis for evaluating and classifying levees, which is based primarily on the federal perspective and flood control experiences in the lower Mississippi River Valley, where national floodplain engineering methods and standards were developed. This research examines the evolution of today's flood control policy, and the development of engineering assessment procedures, and the application of geophysical methods to provide critical information about levee failure mechanisms and assessment of flood control systems. This research demonstrates that topographic base maps and Sengpiel sections showing the results of electrical conductivity or resistivity surveys at different frequencies along the levee corridor provide accurate and valuable information to determine the composition of floodplain soils and the foundation stratigraphy to assess modes of levee failure, to aid in the placement of borings to obtain material properties of the levee and foundation, and to determine the extent of levee reaches with similar properties for the engineering analysis. The main

  1. 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

  2. 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.

  3. 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.

  4. Nanoparticles and direct immunosuppression

    PubMed Central

    Ngobili, Terrika A

    2016-01-01

    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

  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. Curved PVDF airborne transducer.

    PubMed

    Wang, H; Toda, M

    1999-01-01

    In the application of airborne ultrasonic ranging measurement, a partially cylindrical (curved) PVDF transducer can effectively couple ultrasound into the air and generate strong sound pressure. Because of its geometrical features, the ultrasound beam angles of a curved PVDF transducer can be unsymmetrical (i.e., broad horizontally and narrow vertically). This feature is desired in some applications. In this work, a curved PVDF air transducer is investigated both theoretically and experimentally. Two resonances were observed in this transducer. They are length extensional mode and flexural bending mode. Surface vibration profiles of these two modes were measured by a laser vibrometer. It was found from the experiment that the surface vibration was not uniform along the curvature direction for both vibration modes. Theoretical calculations based on a model developed in this work confirmed the experimental results. Two displacement peaks were found in the piezoelectric active direction of PVDF film for the length extensional mode; three peaks were found for the flexural bending mode. The observed peak positions were in good agreement with the calculation results. Transient surface displacement measurements revealed that vibration peaks were in phase for the length extensional mode and out of phase for the flexural bending mode. Therefore, the length extensional mode can generate a stronger ultrasound wave than the flexural bending mode. The resonance frequencies and vibration amplitudes of the two modes strongly depend on the structure parameters as well as the material properties. For the transducer design, the theoretical model developed in this work can be used to optimize the ultrasound performance.

  7. Airborne Crowd Density Estimation

    NASA Astrophysics Data System (ADS)

    Meynberg, O.; Kuschk, G.

    2013-10-01

    This paper proposes a new method for estimating human crowd densities from aerial imagery. Applications benefiting from an accurate crowd monitoring system are mainly found in the security sector. Normally crowd density estimation is done through in-situ camera systems mounted on high locations although this is not appropriate in case of very large crowds with thousands of people. Using airborne camera systems in these scenarios is a new research topic. Our method uses a preliminary filtering of the whole image space by suitable and fast interest point detection resulting in a number of image regions, possibly containing human crowds. Validation of these candidates is done by transforming the corresponding image patches into a low-dimensional and discriminative feature space and classifying the results using a support vector machine (SVM). The feature space is spanned by texture features computed by applying a Gabor filter bank with varying scale and orientation to the image patches. For evaluation, we use 5 different image datasets acquired by the 3K+ aerial camera system of the German Aerospace Center during real mass events like concerts or football games. To evaluate the robustness and generality of our method, these datasets are taken from different flight heights between 800 m and 1500 m above ground (keeping a fixed focal length) and varying daylight and shadow conditions. The results of our crowd density estimation are evaluated against a reference data set obtained by manually labeling tens of thousands individual persons in the corresponding datasets and show that our method is able to estimate human crowd densities in challenging realistic scenarios.

  8. First online measurements of sulfuric acid gas in modern heavy-duty diesel engine exhaust: implications for nanoparticle formation.

    PubMed

    Arnold, F; Pirjola, L; Rönkkö, T; Reichl, U; Schlager, H; Lähde, T; Heikkilä, J; Keskinen, J

    2012-10-16

    To mitigate the diesel particle pollution problem, diesel vehicles are fitted with modern exhaust after-treatment systems (ATS), which efficiently remove engine-generated primary particles (soot and ash) and gaseous hydrocarbons. Unfortunately, ATS can promote formation of low-vapor-pressure gases, which may undergo nucleation and condensation leading to formation of nucleation particles (NUP). The chemical nature and formation mechanism of these particles are only poorly explored. Using a novel mass spectrometric method, online measurements of low-vapor-pressure gases were performed for exhaust of a modern heavy-duty diesel engine operated with modern ATS and combusting low and ultralow sulfur fuels and also biofuel. It was observed that the gaseous sulfuric acid (GSA) concentration varied strongly, although engine operation was stable. However, the exhaust GSA was observed to be affected by fuel sulfur level, exhaust after-treatment, and driving conditions. Significant GSA concentrations were measured also when biofuel was used, indicating that GSA can be originated also from lubricant oil sulfur. Furthermore, accompanying NUP measurements and NUP model simulations were performed. We found that the exhaust GSA promotes NUP formation, but also organic (acidic) precursor gases can have a role. The model results indicate that that the measured GSA concentration alone is not high enough to grow the particles to the detected sizes.

  9. 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.

  10. 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...

  11. Synthesis of dispersive iron or iron-silver nanoparticles on engineered capsid pVIII of M13 virus with electronegative terminal peptides

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Nakano, Kazuhiko; Zhang, Shu-liang; Yu, Hui-min

    2015-10-01

    M13 is a filamentous Escherichia coli virus covered with five types of capsid proteins, in which pVIII with 2700 copies was around the cylindered surface and pIII with five copies located at one end of the phage particle. The pIII-engineered M13 phages with enhanced binding specificity toward Fe were screened after five rounds of biopanning, and the one containing ATPTVAMSLSPL peptide at pIII-terminus was selected for mediated synthesis of zero valent (ZV) Fe nanoparticles (NPs) with the wild M13 as control. Under a reducing environment, uniformly dispersed ZVFeNPs with diameter of 5-10 nm were both synthesized and the morphologies after annealing were confirmed to be face-centered cubic type. The synthesized FeNPs mediated by the two phages showed no significant difference, revealing that the pVIII capsid did dominant contribution to metal binding in comparison with the pIII. A novel pVIII-engineered M13 containing AAEEEDPAK at terminus, named as 4ED-pVIII-M13, was constructed and it carried one more negatively charged residue than the wild one (AEGDDPAK). Metal adsorption quantification showed that the binding affinity of the 4ED-pVIII-M13 toward Ag and Ni ions improved to 62 and 18 % from original 21 and 6 %, respectively. The binding affinity toward Fe remained constant ( 85 %). ZVFe-Ag bi-NPs were successfully synthesized through mediation of 4ED-pVIII-M13. Particularly, the Fe:Ag ratio in the bi-NPs was conveniently controlled through changing the molar concentration of FeCl2 and AgNO3 solution before reduction.

  12. 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.

  13. Direct fluorescence detection of microRNA based on enzymatically engineered primer extension poly-thymine (EPEPT) reaction using copper nanoparticles as nano-dye.

    PubMed

    Chi, Bao-Zhu; Liang, Ru-Ping; Qiu, Wei-Bin; Yuan, Yan-Hong; Qiu, Jian-Ding

    2017-01-15

    A new strategy based on enzymatically engineered primer extension poly-thymine (EPEPT) and nanomaterials in situ generation technology is reported for direct detection of microRNA (miRNA) in a fluorescence turn-on format using the sequential and complementary reactions catalyzed by Klenow Fragment exo(-) (KFexo(-)) and terminal deoxynucleotidyl transferase (TdTase). The short miRNA can be efficiently converted into long poly-thymine (polyT) sequences, which function as template for in situ formation of fluorescence copper nanoparticles (CuNPs) as nano-dye for detecting miRNA. The polyT-CuNPs can effectively form and emit intense red fluorescence under the 340nm excitation. For the proof of concept, microRNA-21 (miR-21) was selected as the model target to testify this strategy as a versatile assay platform. By directly using miR-21 as the primer, the simple, rapid and sensitive miRNA detection was successfully achieved with a good linearity between 1pM and 1nM and a detection limit of 100fM. Thus, the EPEPT strategy holds great potential in biochemical sensing research as an efficient and universal platform.

  14. 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.

  15. Airborne transmission of Bordetella pertussis.

    PubMed

    Warfel, Jason M; Beren, Joel; Merkel, Tod J

    2012-09-15

    Pertussis is a contagious, acute respiratory illness caused by the bacterial pathogen Bordetella pertussis. Although it is widely believed that transmission of B. pertussis occurs via aerosolized respiratory droplets, no controlled study has ever documented airborne transmission of pertussis. We set out to determine if airborne transmission occurs between infected and naive animals, utilizing the baboon model of pertussis. Our results showed that 100% of exposed naive animals became infected even when physical contact was prevented, demonstrating that pertussis transmission occurs via aerosolized respiratory droplets.

  16. Influences of water properties on the aggregation and deposition of engineered titanium dioxide nanoparticles in natural waters.

    PubMed

    Li, Ling; Sillanpää, Markus; Risto, Maarit

    2016-12-01

    With the increasing usage of titanium dioxide nanoparticles (NPs), their release into the environment makes it important to understand their transport, fate and behaviour in natural waters. In this study, aggregation and deposition of TiO2 NPs were studied during a 3-h period by using a dynamic light scattering instrument and a UV-vis spectrophotometer, respectively. TiO2 NPs were spiked in 34 lake and 5 brackish water samples at an initial concentration of 10 mg L(-1). Depending on the physicochemical properties of the natural waters, TiO2 NPs exhibited different colloidal stability. In brackish waters with high salinity, TiO2 NPs were prone to aggregate and settled rapidly. Whereas under conditions of humic and humus-poor lake waters, TiO2 NPs were suspended in water column for a longer time without remarkable change in particle size and concentration. Deposition likely occurred in nutrient-rich lakes which had high amount of nitrogen and phosphorus accompanied by high values of conductivity, alkalinity, pH and turbidity. Linear regression analysis revealed the statistically significant relationships (p ≤ 0.008) between the TiO2 NPs stability and these water properties. Our study makes a better understanding of the water properties that control the aggregation and deposition of TiO2 NPs in complex natural waters.

  17. Facile and scalable fabrication engineering of fullerenol nanoparticles by improved alkaline-oxidation approach and its antioxidant potential in maize

    NASA Astrophysics Data System (ADS)

    Liu, Fu-yang; Xiong, Feng-xia; Fan, Yi-kang; Li, Juan; Wang, He-zhong; Xing, Geng-mei; Yan, Feng-ming; Tai, Fu-ju; He, Rui

    2016-11-01

    A feasible in operation, labor-saving and low-cost one-step technology to fabricate fullerenol nanoparticles (FNPs) up to 10 g in laboratory was developed by improved alkaline-oxidation approach using moderately concentrated sodium hydroxide solution as the hydroxylation agent and o-dichlorobenzene as the solvent. This strategy paves the avenue for industrial-scale bulk production of FNPs. The resulted product, [C60(OH)22·8H2O]n, were characterized by various measurements including matrix-assisted laser desorption ionization time-of-flight mass spectrometry, high-resolution 1H nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, UV-Visible spectrophotometer, thermogravimetric analysis, differential scanning calorimetry, dynamic light scattering analysis, scanning electron microscopy, and electron spin resonance spectrometer. Radical scavenging assay in vitro confirmed the high efficiency of water-soluble [C60(OH)22·8H2O]n as a novel radical scavenger. Furthermore, [C60(OH)22·8H2O]n as an excellent candidate has the potential to serve as the plant defense stimulation agent in maize.

  18. Surface engineered Poly(lactide-co-glycolide) nanoparticles for intracellular delivery: uptake and cytotoxicity--a confocal raman microscopic study.

    PubMed

    Romero, Gabriela; Estrela-Lopis, Irina; Zhou, Jie; Rojas, Elena; Franco, Ana; Espinel, Christian Sanchez; Fernández, Africa González; Gao, Changyou; Donath, Edwin; Moya, Sergio E

    2010-11-08

    Confocal Raman Microscopy (CRM) is used to study the cell internalization of poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) fabricated by emulsion techniques with either poly(ethylene imine) (PEI) or bovine serum albumin (BSA) as surface stabilizers. HepG2 cells were exposed to PEI and BSA stabilized PLGA NPs. Spontaneous Confocal Raman Spectra taken in one and the same spot of exposed cells showed bands arising from the cellular environment as well as bands characteristic for PLGA, proving that the PLGA NPs have been internalized. It was found that PLGA NPs preferentially colocalize with lipid bodies. The results from Raman spectroscopy are compared with flow cytometry and confocal scanning laser microscopy (CLSM) data. The advantages of CRM as a label-free technique over flow cytometry and CLSM are discussed. Additionally, cell viability studies by means of quick cell counting solution and MTT tests in several cell lines show a generally low toxicity for both PEI and BSA stabilized PLGA NPs, with BSA stabilized PLGA NPs having an even lower toxicity than PEI stabilized.

  19. Controlled Self-Assembly of Proteins into Discrete Nanoarchitectures Templated by Gold Nanoparticles via Monovalent Interfacial Engineering.

    PubMed

    Ma, Lingzhi; Li, Feng; Fang, Ti; Zhang, Jianting; Wang, Qiangbin

    2015-05-27

    Designed rational assembly of proteins promises novel properties and functionalities as well as new insights into the nature of life. De novo design of artificial protein nanostructures has been achieved using protein subunits or peptides as building blocks. However, controlled assembly of protein nanostructures into higher-order discrete nanoarchitectures, rather than infinite arrays or aggregates, remains a challenge due to the complex or symmetric surface chemistry of protein nanostructures. Here we develop a facile strategy to control the hierarchical assembly of protein nanocages into discrete nanoarchitectures with gold nanoparticles (AuNPs) as scaffolds via rationally designing their interfacial interaction. The protein nanocage is monofunctionalized with a polyhistidine tag (Histag) on the external surface through a mixed assembly strategy, while AuNPs are modified with Ni(2+)-NTA chelates, so that the protein nanocage can controllably assemble onto the AuNPs via the Histag-Ni(2+) affinity. Discrete protein nanoarchitectures with tunable composition can be generated by stoichiometric control over the ratio of protein nanocage to AuNP or change of AuNP size. The methodology described here is extendable to other protein nanostructures and chemically synthesized nanomaterials, and can be borrowed by synthetic biology for biomacromolecule manipulation.

  20. The Smart Targeting of Nanoparticles

    PubMed Central

    Friedman, Adam D.; Claypool, Sarah E.; Liu, Rihe

    2014-01-01

    One major challenge in nanomedicine is how to selectively deliver nanoparticles to diseased tissues. Nanoparticle delivery system requires targeting for specific delivery to pathogenic sites when enhanced permeability and retention (EPR) is not suitable or inefficient. Functionalizing nanoparticles is a widely-used technique that allows for conjugation with targeting ligands, which possess inherent ability to direct selective binding to cell types or states and, therefore, confer “smartness” to nanoparticles. This review illustrates methods of ligand-nanoparticle functionalization, provides a cross-section of various ligand classes, including small molecules, peptides, antibodies, engineered proteins, or nucleic acid aptamers, and discusses some unconventional approaches currently under investigation. PMID:23470005

  1. Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

    SciTech Connect

    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-alkanes 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.

  2. Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

    DOE PAGES

    Lucachick, Glenn; Curran, Scott; Storey, John Morse; ...

    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

  3. 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.

  4. 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.

  5. Engineered nanoparticles of titanium dioxide (TIO2): Uptake and biological effects in a sea bass cell line.

    PubMed

    Picchietti, S; Bernini, C; Stocchi, V; Taddei, A R; Meschini, R; Fausto, A M; Rocco, L; Buonocore, F; Cervia, D; Scapigliati, G

    2017-02-01

    With the rapid development of nanotechnology there has been a corresponding increase in the application of titanium dioxide nanoparticles (TiO2-NPs) in various consumer and industrial products, consequently their potential health hazards and environmental effects are considered an aspect of great concern. In the present study, in order to assess the impact of TiO2-NPs in the marine environment, the biological effects of TiO2-NPs on a sea bass cell line (DLEC) were investigated. Cells were exposed for 24 h to different concentrations of TiO2-NPs (1, 8, 40, 200 and 1000 μg/ml) or co-exposed with CdCl2 (Cd). The effects of UV light irradiation were also investigated in cells treated with TiO2-NPs and/or Cd. The internalization of TiO2-NPs and the morphological cell modifications induced by the treatments were examined by transmission and scanning electron microscopy, this latter coupled with energy dispersive X-ray spectroscopy (EDS) for particle element detection. In addition, the effects of controlled exposures were studied evaluating the cytotoxicity, the DNA damage and the expression of inflammatory genes. Our study indicates that TiO2-NPs were localized on the cell surface mainly as agglomerates revealed by EDS analysis and that they were uptaken by the cells inducing morphological changes. Photoactivation of TiO2-NPs and/or co-exposure with Cd affects ATP levels and it contributes to induce acute cellular toxicity in DLEC cells dependent on Ti concentration. The inflammatory potential and the DNA damage, this latter displayed through a caspase-3 independent apoptotic process, were also demonstrated. Overall our data suggest that the interaction of TiO2-NPs with marine water contaminants, such as cadmium, and the UV irradiation, may be an additional threat to marine organisms.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Routing architecture and security for airborne networks

    NASA Astrophysics Data System (ADS)

    Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

    2009-05-01

    Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

  11. Nanoparticles: potential biomarker harvesters.

    PubMed

    Geho, David H; Jones, Clinton D; Petricoin, Emanuel F; Liotta, Lance A

    2006-02-01

    A previously untapped bank of information resides within the low molecular weight proteomic fraction of blood. Intensive efforts are underway to harness this information so that it can be used for early diagnosis of diseases such as cancer. The physicochemical malleability and high surface areas of nanoparticle surfaces make them ideal candidates for developing biomarker harvesting platforms. Given the variety of engineering strategies afforded through nanoparticle technologies, a significant goal is to tailor nanoparticle surfaces to selectively bind a subset of biomarkers, sequestering them for later study using high sensitivity proteomic tests. To date, applications of nanoparticles have largely focused on imaging systems and drug delivery vectors. As such, biomarker harvesting is an underutilized application of nanoparticle technology and is an area of nanotechnology research that will likely undergo substantial growth.

  12. 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''.

  13. 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.

  14. 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

  15. 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

  16. 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

    2015-07-24

    Consumer products containing engineered nanoparticles (ENP) are already entering the marketplace. This leads, inter al