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Sample records for situ nanoparticle diagnostics

  1. In situ nanoparticle diagnostics by multi-wavelength Rayleigh-Mie scattering ellipsometry

    CERN Document Server

    Gebauer, G

    2003-01-01

    We present and discuss the method of multiple-wavelength Rayleigh-Mie scattering ellipsometry for the in situ analysis of nanoparticles. It is applied to the problem of nanoparticles suspended in low-pressure plasmas. We discuss experimental results demonstrating that the size distribution and the complex refractive index can be determined with high accuracy and present a study on the in situ analysis of etching of melamine-formaldehyde nanoparticles suspended in an oxygen plasma. It is also shown that particles with a shell structure (core plus mantle) can be analysed by Rayleigh-Mie scattering ellipsometry. Rayleigh-Mie scattering ellipsometry is also applicable to in situ analysis of nanoparticles under high gas pressures and in liquids.

  2. Laser-induced incandescence (LII) diagnostic for in situ monitoring of nanoparticle synthesis in a high-pressure arc discharge

    Science.gov (United States)

    Yatom, Shurik; Vekselman, Vladislav; Mitrani, James; Stratton, Brentley; Raitses, Yevgeny; LaboratoryPlasma Nanosynthesis Team

    2016-10-01

    A DC arc discharge is commonly used for synthesis of carbon nanoparticles, including buckyballs, carbon nanotubes, and graphene flakes. In this work we show the first results of nanoparticles monitored during the arc discharge. The graphite electrode is vaporized by high current (60 A) in a buffer Helium gas leading to nanoparticle synthesis in a low temperature plasma. The arc was shown to oscillate, which can possibly influence the nano-synthesis. To visualize the nanoparticles in-situ we employ the LII technique. The nanoparticles with radii >50 nm, emerging from the arc area are heated with a short laser pulse and incandesce. The resulting radiation is captured with an ICCD camera, showing the location of the generated nanoparticles. The images of incandescence are studied together with temporally synchronized fast-framing imaging of C2 emission, to connect the dynamics of arc instabilities, C2 molecules concentration and nanoparticles. The time-resolved incandescence signal is analyzed with combination of ex-situ measurements of the synthesized nanoparticles and LII modeling, to provide the size distribution of produced nanoparticles. This work was supported by US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

  3. LUMINESCENCE DIAGNOSTICS OF TUMORS WITH UPCONVERSION NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    V. V. Rocheva

    2016-01-01

    Full Text Available Background: To improve quality of surgery in oncology, it is necessary to completely remove the tumor, including its metastases, to minimize injury to normal tissues and to reduce duration of an intervention. Modern methods of detection based on radiological computerized tomography and magnetic resonance imaging can identify a tumor after its volume has become big enough, i.e. it contains more than 10 billion cells. Therefore, an improvement of sensitivity and resolution ability of diagnostic tools to identify early stages of malignant neoplasms seems of utmost importance. Aim: To demonstrate the potential of a new class of anti-Stokes luminescence nanoparticles for deep optical imaging with high contrast of malignant tumors. Materials and methods: Upconversion nanoparticles with narrow dispersion and a  size of 70 to 80  nm, with a  core/shell structure of NaYF4:Yb3+:Tm3+/NaYF4 were used in the study. The nanoparticles have an intensive band of anti-Stokes photoluminescence at a wavelength of 800  nm under irradiation with a  wavelength of 975  nm (both wavelengths are within the transparency window for biological tissues. The conversion coefficient of the excitation radiation into the anti-Stokes luminescence was 9%. To increase the time during which nanoparticles can circulate in blood flow of small animals, the nanoparticles were covered by a  biocompatible amphiphilic polymer shell. As a  tumor model we used Lewis epidermoid carcinoma transfected to mice. Results: We were able to obtain stable water colloids of nanoparticles covered with amphiphilic polymer that could preserve their initial size at least for one month. The use of upconversion nanoparticles with a  hydrophilic shell made of intermittent maleic anhydride and octadecene co-polymer with subsequent coating with diglycidyl polyethylene glycol ether allowed for reduction of non-specific reaction of nanoparticles with plasma proteins. In its turn, it resulted in an

  4. Nanoparticle functionalization for brain targeting drug delivery and diagnostic

    DEFF Research Database (Denmark)

    Gomes, Maria João; Mendes, Bárbara; Martins, Susana

    2016-01-01

    carriers to cross the BBB and achieve brain, and their functionalization strategies are described; and finally the delivery of nanoparticles to the target moiety, as diagnostics or therapeutics. Therefore, this chapter is focused on how the nanoparticle surface may be functionalized for drug delivery......-mediated drug transport across the BBB, where nanoparticles take advantage of physiological receptor-mediated transport processes....

  5. Nanoparticles laden in situ gel for sustained ocular drug delivery

    Directory of Open Access Journals (Sweden)

    Himanshu Gupta

    2013-01-01

    Full Text Available Proper availability of drug on to corneal surface is a challenging task. However, due to ocular physiological barriers, conventional eye drops display poor ocular bioavailability of drugs (< 1%. To improve precorneal residence time and ocular penetration, earlier our group developed and evaluated in situ gel and nanoparticles for ocular delivery. In interest to evaluate the combined effect of in situ gel and nanoparticles on ocular retention, we combined them. We are the first to term this combination as "nanoparticle laden in situ gel", that is, poly lactic co glycolic acid nanoparticle incorporated in chitosan in situ gel for sparfloxacin ophthalmic delivery. The formulation was tested for various physicochemical properties. It showed gelation pH near pH 7.2. The observation of acquired gamma camera images showed good retention over the entire precorneal area for sparfloxacin nanoparticle laden in situ gel (SNG as compared to marketed formulation. SNG formulation cleared at a very slow rate and remained at corneal surface for longer duration as no radioactivity was observed in systemic circulation. The developed formulation was found to be better in combination and can go up to the clinical evaluation and application.

  6. Supramolecular Nanoparticles for Molecular Diagnostics and Therapeutics

    Science.gov (United States)

    Chen, Kuan-Ju

    Over the past decades, significant efforts have been devoted to explore the use of various nanoparticle-based systems in the field of nanomedicine, including molecular imaging and therapy. Supramolecular synthetic approaches have attracted lots of attention due to their flexibility, convenience, and modularity for producing nanoparticles. In this dissertation, the developmental story of our size-controllable supramolecular nanoparticles (SNPs) will be discussed, as well as their use in specific biomedical applications. To achieve the self-assembly of SNPs, the well-characterized molecular recognition system (i.e., cyclodextrin/adamantane recognition) was employed. The resulting SNPs, which were assembled from three molecular building blocks, possess incredible stability in various physiological conditions, reversible size-controllability and dynamic disassembly that were exploited for various in vitro and in vivo applications. An advantage of using the supramolecular approach is that it enables the convenient incorporation of functional ligands onto SNP surface that confers functionality ( e.g., targeting, cell penetration) to SNPs. We utilized SNPs for molecular imaging such as magnetic resonance imaging (MRI) and positron emission tomography (PET) by introducing reporter systems (i.e., radio-isotopes, MR contrast agents, and fluorophores) into SNPs. On the other hand, the incorporation of various payloads, including drugs, genes and proteins, into SNPs showed improved delivery performance and enhanced therapeutic efficacy for these therapeutic agents. Leveraging the powers of (i) a combinatorial synthetic approach based on supramolecular assembly and (ii) a digital microreactor, a rapid developmental pathway was developed that is capable of screening SNP candidates for the ideal structural and functional properties that deliver optimal performance. Moreover, SNP-based theranostic delivery systems that combine reporter systems and therapeutic payloads into a

  7. Application of Nanoparticles in Diagnostic Imaging via ...

    African Journals Online (AJOL)

    ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These imaging modalities differ not only in resolution, but also in the instrumentation and the type of nanoparticle that can be employed as its assistant. Of these imaging techniques, ultrasound is one of ...

  8. Magnetic nanoparticles for therapy and diagnostics

    Czech Academy of Sciences Publication Activity Database

    Pollert, Emil; Kašpar, P.; Závěta, Karel; Herynek, V.; Burian, M.; Jendelová, Pavla

    2013-01-01

    Roč. 49, č. 1 (2013), s. 7-10 ISSN 0018-9464 R&D Projects: GA MPO FR-TI3/521 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : Curie temperature * magnetic fluid hyperthermia * magnetic nanoparticles * relaxivity * contrast agent * hypertermia * magnetic resonance imaging Subject RIV: BM - Solid Matter Physics ; Magnetism; FD - Oncology ; Hematology (UEM-P) Impact factor: 1.213, year: 2013

  9. Au nanoparticles in PMMA matrix: In situ synthesis and the effect of Au nanoparticles on PMMA conductivity

    International Nuclear Information System (INIS)

    Yilmaz, Eda; Suzer, Sefik

    2010-01-01

    Thin PMMA films with and without gold nanoparticles were subjected to ±10 V d.c. and a.c. (square wave) excitations in various frequencies while recording their XPS spectra, and the resulting differences due to charging were examined. Both pure PMMA films and films containing gold nanoparticles showed charging shifts, but those of pure PMMA were more extensive than of PMMA containing gold nanoparticles, suggesting enhanced conductivity, induced by the incorporated gold nanoparticles. Non-charging behavior for these films was also observed with the increase of gold nanoparticle concentration. Gold nanoparticles were in situ synthesized and photo-patterned within the polymer films by UV irradiation.

  10. Magnetic nanoparticles in magnetic resonance imaging and diagnostics.

    Science.gov (United States)

    Rümenapp, Christine; Gleich, Bernhard; Haase, Axel

    2012-05-01

    Magnetic nanoparticles are useful as contrast agents for magnetic resonance imaging (MRI). Paramagnetic contrast agents have been used for a long time, but more recently superparamagnetic iron oxide nanoparticles (SPIOs) have been discovered to influence MRI contrast as well. In contrast to paramagnetic contrast agents, SPIOs can be functionalized and size-tailored in order to adapt to various kinds of soft tissues. Although both types of contrast agents have a inducible magnetization, their mechanisms of influence on spin-spin and spin-lattice relaxation of protons are different. A special emphasis on the basic magnetism of nanoparticles and their structures as well as on the principle of nuclear magnetic resonance is made. Examples of different contrast-enhanced magnetic resonance images are given. The potential use of magnetic nanoparticles as diagnostic tracers is explored. Additionally, SPIOs can be used in diagnostic magnetic resonance, since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.

  11. Special Resins for Stereolithography: In Situ Generation of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gabriele Taormina

    2018-02-01

    Full Text Available The limited availability of materials with special properties represents one of the main limitations to a wider application of polymer-based additive manufacturing technologies. Filled resins are usually not suitable for vat photo-polymerization techniques such as stereolithography (SLA or digital light processing (DLP due to a strong increment of viscosity derived from the presence of rigid particles within the reactive suspension. In the present paper, the possibility to in situ generate silver nanoparticles (AgNPs starting from a homogeneous liquid system containing a well dispersed silver salt, which is subsequently reduced to metallic silver during stereolithographic process, is reported. The simultaneous photo-induced cross-linking of the acrylic resin produces a filled thermoset resin with thermal-mechanical properties significantly enhanced with respect to the unfilled resin, even at very low AgNPs concentrations. With this approach, the use of silver salts having carbon-carbon double bonds, such as silver acrylate and silver methacrylate, allows the formation of a nanocomposite structure in which the release of by-products is minimized due to the active role of all the reactive components in the three dimensional (3D-printing processes. The synergy, between this nano-technology and the geometrical freedom offered by SLA, could open up a wide spectrum of potential applications for such a material, for example in the field of food packaging and medical and healthcare sectors, considering the well-known antimicrobial effects of silver nanoparticles.

  12. In situ measurements of magnetic nanoparticles after placenta perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Robert, E-mail: robert.mueller@ipht-jena.de [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany); Gläser, Marcus [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany); University of Applied Sciences, Jena (Germany); Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard [Department of Obstetrics and Gynecology, Jena University Hospital (Germany); Hofmann, Andreas [HTS Systeme GmbH, Wallenfels (Germany); Fritzsche, Wolfgang [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany)

    2015-04-15

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10{sup −8} Am{sup 2}) was used for long term measurements of magnetic NP of 100–150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  13. In situ measurements of magnetic nanoparticles after placenta perfusion

    Science.gov (United States)

    Müller, Robert; Gläser, Marcus; Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard; Hofmann, Andreas; Fritzsche, Wolfgang

    2015-04-01

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10-8 Am2) was used for long term measurements of magnetic NP of 100-150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  14. Brain Tumor Diagnostics and Therapeutics with Superparamagnetic Ferrite Nanoparticles.

    Science.gov (United States)

    Hyder, Fahmeed; Manjura Hoque, S

    2017-01-01

    Ferrite nanoparticles (F-NPs) can transform both cancer diagnostics and therapeutics. Superparamagnetic F-NPs exhibit high magnetic moment and susceptibility such that in presence of a static magnetic field transverse relaxation rate of water protons for MRI contrast is augmented to locate F-NPs (i.e., diagnostics) and exposed to an alternating magnetic field local temperature is increased to induce tissue necrosis (i.e., thermotherapy). F-NPs are modified by chemical synthesis of mixed spinel ferrites as well as their size, shape, and coating. Purposely designed drug-containing nanoparticles (D-NPs) can slowly deliver drugs (i.e., chemotherapy). Convection-enhanced delivery (CED) of D-NPs with MRI guidance improves glioblastoma multiforme (GBM) treatment. MRI monitors the location of chemotherapy when D-NPs and F-NPs are coadministered with CED. However superparamagnetic field gradients produced by F-NPs complicate MRI readouts (spatial distortions) and MRS (extensive line broadening). Since extracellular pH (pH e ) is a cancer hallmark, pH e imaging is needed to screen cancer treatments. Biosensor imaging of redundant deviation in shifts (BIRDS) extrapolates pH e from paramagnetically shifted signals and the pH e accuracy remains unaffected by F-NPs. Hence effect of both chemotherapy and thermotherapy can be monitored (by BIRDS), whereas location of F-NPs is revealed (by MRI). Smarter tethering of nanoparticles and agents will impact GBM theranostics.

  15. Brain Tumor Diagnostics and Therapeutics with Superparamagnetic Ferrite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Fahmeed Hyder

    2017-01-01

    Full Text Available Ferrite nanoparticles (F-NPs can transform both cancer diagnostics and therapeutics. Superparamagnetic F-NPs exhibit high magnetic moment and susceptibility such that in presence of a static magnetic field transverse relaxation rate of water protons for MRI contrast is augmented to locate F-NPs (i.e., diagnostics and exposed to an alternating magnetic field local temperature is increased to induce tissue necrosis (i.e., thermotherapy. F-NPs are modified by chemical synthesis of mixed spinel ferrites as well as their size, shape, and coating. Purposely designed drug-containing nanoparticles (D-NPs can slowly deliver drugs (i.e., chemotherapy. Convection-enhanced delivery (CED of D-NPs with MRI guidance improves glioblastoma multiforme (GBM treatment. MRI monitors the location of chemotherapy when D-NPs and F-NPs are coadministered with CED. However superparamagnetic field gradients produced by F-NPs complicate MRI readouts (spatial distortions and MRS (extensive line broadening. Since extracellular pH (pHe is a cancer hallmark, pHe imaging is needed to screen cancer treatments. Biosensor imaging of redundant deviation in shifts (BIRDS extrapolates pHe from paramagnetically shifted signals and the pHe accuracy remains unaffected by F-NPs. Hence effect of both chemotherapy and thermotherapy can be monitored (by BIRDS, whereas location of F-NPs is revealed (by MRI. Smarter tethering of nanoparticles and agents will impact GBM theranostics.

  16. Coarsening of Pd nanoparticles in an oxidizing atmosphere studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chorkendorff, Ib; Dahl, Søren

    2016-01-01

    The coarsening of supported palladium nanoparticles in an oxidizing atmosphere was studied in situ by means of transmission electron microscopy (TEM). Specifically, the Pd nanoparticles were dispersed on a planar and amorphous Al2O3 support and were observed during the exposure to 10 mbar technical...... for the Ostwald ripening process indicates that the observed change in the particle size distribution can be accounted for by wetting of the Al2O3 support by the larger Pd nanoparticles....

  17. Gold Nanoparticles and Nanocomposites in Clinical Diagnostics Using Electrochemical Methods

    Directory of Open Access Journals (Sweden)

    Pranjal Chandra

    2013-01-01

    Full Text Available Progress and development in clinical diagnostics certainly focus upon the advances in the nanomaterials, particularly gold nanoparticles (AuNPs that offer promise to solve the biocompatible and sensitive detection systems. This paper focuses on the recent application of AuNPs in clinical diagnosis. Various important methods of AuNPs synthesis and their application in clinical detection of various biomolecules using electrochemical detection methods have been described. AuNPs alone and in various composites are also described based on the various biosensors design recently published for the detection of cancer biomarkers, proteins, bacteria, and cancer cells. The effect of AuNPs type and size in clinical detection has also been briefly illustrated.

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

    Energy Technology Data Exchange (ETDEWEB)

    Byeon, Jeong Hoon, E-mail: postjb@yu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Park, Jae Hong; Peters, Thomas M. [Department of Occupational and Environmental Health, University of Iowa, IA 52242 (United States); Roberts, Jeffrey T., E-mail: jtrob@purdue.edu [Department of Chemistry, Purdue University, IN 47907 (United States)

    2015-07-15

    Highlights: • The cytotoxicity of model welding particles was modulated through in situ passivation. • Model welding particles were incorporated with chitosan nanoparticles for passivation. • In vitro assay revealed that the passivated particles had a lower cytotoxicity. • Passivation with chitosan adhesive or graphite paste could also reduce cytotoxicity. • This method would be suitable for efficient reduction of inhalable toxic components. - Abstract: 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.

  19. In situ spectroscopy of ligand exchange reactions at the surface of colloidal gold and silver nanoparticles

    International Nuclear Information System (INIS)

    Dinkel, Rebecca; Peukert, Wolfgang; Braunschweig, Björn

    2017-01-01

    Gold and silver nanoparticles with their tunable optical and electronic properties are of great interest for a wide range of applications. Often the ligands at the surface of the nanoparticles have to be exchanged in a second step after particle formation in order to obtain a desired surface functionalization. For many techniques, this process is not accessible in situ . In this review, we present second-harmonic scattering (SHS) as an inherently surface sensitive and label-free optical technique to probe the ligand exchange at the surface of colloidal gold and silver nanoparticles in situ and in real time. First, a brief introduction to SHS and basic features of the SHS of nanoparticles are given. After that, we demonstrate how the SHS intensity decrease can be correlated to the thiol coverage which allows for the determination of the Gibbs free energy of adsorption and the surface coverage. (topical review)

  20. In situ synthesis of nanoparticles on substrates by inkjet printing

    KAUST Repository

    Abulikemu, Mutalifu

    2014-12-23

    Nanoparticles may be formed on a substrate by mixing precursor solutions deposited by an inkjet printer. A first solution is deposited on a substrate from a first inkjet print cartridge. Then, a second solution is deposited on the substrate from a second inkjet print cartridge. The solutions may be printed in an array of droplets on the substrate. Nanoparticles form when droplets of the first solution overlap with droplets of the second solution. In one example, the nanoparticles may be gold nanoparticles formed from mixing a first solution of 1,2-dichlorobenzene (DCB) and oleylamine and a second solution of gold chloride trihydrite and dimethyl sulfoxide (DMSO). The nanoparticles may be incorporated into optoelectronic devices.

  1. Characterization of Silver Nanoparticle In Situ Synthesis on Porous Sericin Gel for Antibacterial Application

    OpenAIRE

    Tao, Gang; Liu, Lina; Wang, Yejing; Chang, Huaipu; Zhao, Ping; Zuo, Hua; He, Huawei

    2016-01-01

    Sericin from Bombyx mori cocoon has good hydrophilicity, reaction activity, biocompatibility, and biodegradability, which has shown great potentials for biomedical materials. Here, an ultraviolet light-assisted in situ synthesis approach is developed to immobilize silver nanoparticles on the surface of sericin gel. The amount of silver nanoparticles immobilized on the surface of sericin gel could be regulated by the irradiation time. The porous structure and property of sericin gel were not a...

  2. Tribological behavior of in situ Ag nanoparticles/polyelectrolyte composite molecular deposition films

    International Nuclear Information System (INIS)

    Guo Yanbao; Wang Deguo; Liu Shuhai

    2010-01-01

    Multilayer polyelectrolyte films containing silver ions were obtained by molecular deposition method on a glass plate or a quartz substrate. The in situ Ag nanoparticles were synthesized in the multilayer polyelectrolyte films which were put into fresh NaBH 4 aqueous solution. The structure and surface morphology of composite molecular deposition films were observed by UV-vis spectrophotometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Tribological characteristic was investigated by AFM and micro-tribometer. It was found that the in situ Ag nanoparticles/polyelectrolyte composite molecular deposition films have lower coefficient of friction and higher anti-wear life than pure polyelectrolyte molecular deposition films.

  3. Simulated plasma facing component measurements for an in situ surface diagnostic on Alcator C-Moda)

    Science.gov (United States)

    Hartwig, Z. S.; Whyte, D. G.

    2010-10-01

    The ideal in situ plasma facing component (PFC) diagnostic for magnetic fusion devices would perform surface element and isotope composition measurements on a shot-to-shot (˜10 min) time scale with ˜1 μm depth and ˜1 cm spatial resolution over large areas of PFCs. To this end, the experimental adaptation of the customary laboratory surface diagnostic—nuclear scattering of MeV ions—to the Alcator C-Mod tokamak is being guided by ACRONYM, a Geant4 synthetic diagnostic. The diagnostic technique and ACRONYM are described, and synthetic measurements of film thickness for boron-coated PFCs are presented.

  4. Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    DEFF Research Database (Denmark)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian

    2012-01-01

    Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first-principles......-parametrized thermodynamic model. Our experimental observations show that the initially irregular morphologies of the as-sythesized porous nanoparticles undergo changes at high temperatures to morphologies having faceted external surfaces with voids present in the interior of the particles. The increasing size of stable...

  5. In-situ TEM imaging of the anisotropic etching of graphene by metal nanoparticles.

    Science.gov (United States)

    Wei, Jiake; Xu, Zhi; Wang, Hao; Tian, Xuezeng; Yang, Shize; Wang, Lifen; Wang, Wenlong; Bai, Xuedong

    2014-11-21

    Few-layer graphene was successfully tailored with smooth edges along crystallographic directions by Joule heating-driven tungsten nanoparticles inside a transmission electron microscope. The dynamic process was monitored in real time at the atomic resolution level. These high-resolution in-situ observations show that the neighboring graphene layers joined together to form closed edges, which is in contrast to the supposed open edges formed with hydrogen passivation. The tungsten nanoparticles transformed to W₂C in the intermediate stage of etching and to WC after etching, suggesting that carbon dissolution helped the continuous action of the metal nanoparticles in the catalytic anisotropic etching reaction.

  6. In situ gold nanoparticles formation: contrast agent for dental optical coherence tomography.

    Science.gov (United States)

    Braz, Ana K S; de Araujo, Renato E; Ohulchanskyy, Tymish Y; Shukla, Shoba; Bergey, Earl J; Gomes, Anderson S L; Prasad, Paras N

    2012-06-01

    In this work we demonstrate the potential use of gold nanoparticles as contrast agents for the optical coherence tomography (OCT) imaging technique in dentistry. Here, a new in situ photothermal reduction procedure was developed, producing spherical gold nanoparticles inside dentinal layers and tubules. Gold ions were dispersed in the primer of commercially available dental bonding systems. After the application and permeation in dentin by the modified adhesive systems, the dental bonding materials were photopolymerized concurrently with the formation of gold nanoparticles. The gold nanoparticles were visualized by scanning electron microscopy (SEM). The SEM images show the presence of gold nanospheres in the hybrid layer and dentinal tubules. The diameter of the gold nanoparticles was determined to be in the range of 40 to 120 nm. Optical coherence tomography images were obtained in two- and three-dimensions. The distribution of nanoparticles was analyzed and the extended depth of nanosphere production was determined. The results show that the OCT technique, using in situ formed gold nanoparticles as contrast enhancers, can be used to visualize dentin structures in a non-invasive and non-destructive way.

  7. Retention of in-situ surface modified silica nanoparticles for carbon dioxide foam stabilization in sandpack

    Science.gov (United States)

    Adil, Muhammad

    2014-10-01

    Nanoparticle-stabilized CO2 foams have been used for mobility control for CO2 flooding; however, raw nanosilica particles which are hydrophilic in nature tend to develop unstable CO2 foam under certain reservoir conditions. The unstable foam leads to particles aggregation resulting in complete retention while propagating in a long distance, deep into the reservoir. This can be avoided by the application of a particular coating of a specific surfactant, polymer or their combination to the surface of the nanoparticles. The in-situ surface activation of unmodified SiO2 nanoparticles by interaction with mixed surfactant (TX100:SDBS) in aqueous media has been studied with extensive experiments using variable volumetric ratios. The retention of in-situ surface-modified nanoparticles was evaluated by the injection of the dispersion of nanoparticles through a sandpack. The loading of nanoparticles in dispersion was ranging from concentrated (5 wt %) to dilute (0.1 wt %). Effluent nanoparticles concentration histories were measured to determine the retained particles in the sandpack. Little retention (injected over two pore volumes) was attained for 0.5% SiO2 and volumetric ratio of 2:1 (TX100:SDBS). These results were concluded in terms of surface charges, adsorption isotherm, surface adsorption, and DLVO theory between particles and rock.

  8. In situ synthesis of silver chloride nanoparticles into bacterial cellulose membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hu Weili; Chen Shiyan; Li Xin; Shi Shuaike; Shen Wei; Zhang Xiang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Key Laboratory of Textile Science and Technology (Ministry of Education), College of Materials Science and Engineering, Donghua University, Shanghai, 201620 (China); Wang Huaping, E-mail: wanghp@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Key Laboratory of Textile Science and Technology (Ministry of Education), College of Materials Science and Engineering, Donghua University, Shanghai, 201620 (China)

    2009-05-05

    In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative procedure is facile and versatile, and provides a simple route to manufacturing of useful antimicrobial membranes, which would be a good alternative for antimicrobial wound dressing.

  9. APPLICATION OF NANOPARTICLES IN DIAGNOSTIC IMAGING VIA ULTRASONOGRAPHY

    Directory of Open Access Journals (Sweden)

    Dr. Vicky V. Mody PhD

    2011-01-01

    Full Text Available The effectiveness of an imaging technique not only depends on its ability to image quantitatively both morphological and physiological functions of the tissue, but also on the contrast agent used to communicate with biomolecules. Several types of contrast media are used in medical imaging and they can roughly be cataloged based on the imaging modalities where they are used. More importantly, the use of contrast agent with their size ranging in nanometer scale has become general practice in medical diagnosis. As the matter of fact, nanoparticles have fascinated scientist for over a century and are now heavily utilized in biomedical sciences and engineering as they are long known to communicate effectively with the biomolecules. Today these materials can be synthesized and modified with various chemical functional groups which allow them to be conjugated with antibodies, ligands, and drugs of interest and thus opening a wide range of potential applications in biotechnology, and more importantly in diagnostic medical imaging via ultrasound, computed tomography (CT, magnetic resonance imaging (MRI, and positron emission tomography (PET. These imaging modalities differ not only in resolution, but also in the instrumentation and the type of nanoparticle that can be employed as its assistant. Of these imaging techniques, ultrasound is one of the oldest imaging modality which is still widely used to examine internal organs of the body and diagnose potential disease states such as cancer, plague, clots, and swelling. Various articles have been published over the period of years detailing the instrumentation and the applications of ultrasonography, but very few have emphasized the importance of particle size in developing a successful contrast agent for ultrasonography. Thus in the present review article we aim to present the basic principles involved in developing successful contrast agent for Ultrasound imaging. Furthermore, we have also discussed the

  10. In situ ETEM synthesis of NiGa alloy nanoparticles from nitrate salt solution

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Duchstein, Linus Daniel Leonhard; Sharafutdinov, Irek

    2014-01-01

    Metallic alloy nanoparticles (NPs) are synthesized in situ in an environmental transmission electron microscope. Atomic level characterization of the formed alloy NPs is carried out at synthesis conditions by use of high-resolution transmission electron microscopy, electron diffraction and electron...

  11. In-situ transmission electron microscopy growth of nanoparticles under extreme conditions

    International Nuclear Information System (INIS)

    Luce, F. P.; Azevedo, G. de M.; Baptista, D. L.; Zawislak, F. C.; Oliviero, E.; Fichtner, P. F. P.

    2016-01-01

    The formation and time resolved behavior of individual Pb nanoparticles embedded in silica have been studied by in-situ transmission electron microscopy observations at high temperatures (400–1100 °C) and under 200 keV electron irradiation. It is shown that under such extreme conditions, nanoparticles can migrate at long distances presenting a Brownian-like behavior and eventually coalesce. The particle migration phenomenon is discussed considering the influence of the thermal energy and the electron irradiation effects on the atomic diffusion process which is shown to control particle migration. These results and comparison with ex-situ experiments tackle the stability and the microstructure evolution of nanoparticles systems under extreme conditions. It elucidates on the effects of energetic particle irradiation-annealing treatments either as a tool or as a detrimental issue that could hamper their long-term applications in radiation-harsh environments such as in space or nuclear sectors

  12. In-situ transmission electron microscopy growth of nanoparticles under extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Luce, F. P.; Azevedo, G. de M.; Baptista, D. L.; Zawislak, F. C. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970 (Brazil); Oliviero, E. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), CNRS-IN2P3-Université Paris-Sud, 91405 Orsay-Campus (France); Fichtner, P. F. P. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970 (Brazil); Escola de Engenharia, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970 (Brazil)

    2016-01-21

    The formation and time resolved behavior of individual Pb nanoparticles embedded in silica have been studied by in-situ transmission electron microscopy observations at high temperatures (400–1100 °C) and under 200 keV electron irradiation. It is shown that under such extreme conditions, nanoparticles can migrate at long distances presenting a Brownian-like behavior and eventually coalesce. The particle migration phenomenon is discussed considering the influence of the thermal energy and the electron irradiation effects on the atomic diffusion process which is shown to control particle migration. These results and comparison with ex-situ experiments tackle the stability and the microstructure evolution of nanoparticles systems under extreme conditions. It elucidates on the effects of energetic particle irradiation-annealing treatments either as a tool or as a detrimental issue that could hamper their long-term applications in radiation-harsh environments such as in space or nuclear sectors.

  13. Mechanistic analysis of Zein nanoparticles/PLGA triblock in situ forming implants for glimepiride

    Science.gov (United States)

    Ahmed, Osama Abdelhakim Aly; Zidan, Ahmed Samir; Khayat, Maan

    2016-01-01

    Objectives The study aims at applying pharmaceutical nanotechnology and D-optimal fractional factorial design to screen and optimize the high-risk variables affecting the performance of a complex drug delivery system consisting of glimepiride–Zein nanoparticles and inclusion of the optimized formula with thermoresponsive triblock copolymers in in situ gel. Methods Sixteen nanoparticle formulations were prepared by liquid–liquid phase separation method according to the D-optimal fractional factorial design encompassing five variables at two levels. The responses investigated were glimepiride entrapment capacity (EC), particle size and size distribution, zeta potential, and in vitro drug release from the prepared nanoparticles. Furthermore, the feasibility of embedding the optimized Zein-based glimepiride nanoparticles within thermoresponsive triblock copolymers poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) in in situ gel was evaluated for controlling glimepiride release rate. Results Through the systematic optimization phase, improvement of glimepiride EC of 33.6%, nanoparticle size of 120.9 nm with a skewness value of 0.2, zeta potential of 11.1 mV, and sustained release features of 3.3% and 17.3% drug released after 2 and 24 hours, respectively, were obtained. These desirability functions were obtained at Zein and glimepiride loadings of 50 and 75 mg, respectively, utilizing didodecyldimethylammonium bromide as a stabilizer at 0.1% and 90% ethanol as a common solvent. Moreover, incorporating this optimized formulation in triblock copolymers-based in situ gel demonstrated pseudoplastic behavior with reduction of drug release rate as the concentration of polymer increased. Conclusion This approach to control the release of glimepiride using Zein nanoparticles/triblock copolymers-based in situ gel forming intramuscular implants could be useful for improving diabetes treatment effectiveness. PMID:26893561

  14. In situ TEM study of the coarsening of carbon black supported Pt nanoparticles in hydrogen

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wang, Yan; Jensen, Jens Oluf

    2017-01-01

    The control of sizes and shapes of nanostructures is of tremendous importance for the catalytic activity in electrochemistry and in catalysis more generally. However, due to relatively large surface free energies, nanostructures often sinter to form coarser and more stable structures that may...... not have the intended physicochemical properties. Pt is known to be a very active catalyst in several chemical reactions and for example as carbon supported nanoparticles in fuel cells. The presentation focusses on coarsening mechanisms of Pt nanoparticles supported on carbon black during exposure...... to hydrogen. By means of in situ transmission electron microscopy (TEM), Pt nanoparticle coarsening was monitored in 6 mbar 20 % H2/Ar while ramping up the temperature to ca. 900 °C. Time-resolved TEM images directly reveal that separated ca. 3 nm sized Pt nanoparticles in the pure hydrogen environment...

  15. A light-assisted in situ embedment of silver nanoparticles to prepare functionalized fabrics

    Science.gov (United States)

    Toh, Her Shuang; Faure, Roxanne Line; Mohd Amin, Liyana Bte; Hay, Crystal Yu Fang; George, Saji

    2017-01-01

    This article presents a simple, one-step, in situ generation of silver nanoparticle-functionalized fabrics with antibacterial properties, circumventing the conventional, multistep, time-consuming methods. Silver nanoparticle formation was studied with a library of capping agents (branched polyethylenimine [BPEI] of molecular weight [Mw] 10,000 and 25,000, polyvinylpyrrolidone, polyethylene glycol, polyvinylalcohol and citrate) mixed with silver nitrate. The mixture was then exposed to an assortment of light wavelengths (ultraviolet, infrared and simulated solar light) for studying the light-assisted synthesis of nanoparticles. The formation of nanoparticles corresponded with the reducing capabilities of the polymers wherein BPEI gave the best response. Notably, the irradiation wavelengths had little effect on the formation of the nanoparticle when the total irradiation energy was kept constant. The feasibility of utilizing this method for in situ nanoparticle synthesis on textile fabrics (towel [100% cotton], gauze [100% cotton], rayon, felt [100% polyester] and microfiber [15% nylon, 85% polyester]) was verified by exposing the fabrics soaked in an aqueous solution of 1% (w/v) AgNO3 and 1% (w/v) BPEI (Mw 25,000) to light. The formation of nanoparticles on fabrics and their retention after washing was verified using scanning electron microscopy and quantified by inductively coupled plasma optical emission spectrometry. The functional property of the fabric as an antibacterial surface was successfully demonstrated using model bacteria such as Staphylococcus aureus, Enterococcus faecalis and Escherichia coli. The successful generation of silver nanoparticle-functionalized textile fabrics without the use of caustic chemicals, solvents and excessive heating presents a major step towards realizing a scalable green chemistry for industrial generation of functionalized fabrics for a wide range of applications. PMID:29238173

  16. In situ synthesis and characterization of magnetic nanoparticles in shells of biodegradable polyelectrolyte microcapsules

    Energy Technology Data Exchange (ETDEWEB)

    Lyubutin, I.S. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky av. 59, Moscow 119333 (Russian Federation); Starchikov, S.S., E-mail: sergey.s.starchikov@gmail.com [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky av. 59, Moscow 119333 (Russian Federation); Bukreeva, T.V. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky av. 59, Moscow 119333 (Russian Federation); Lysenko, I.A. [National Research Center “Kurchatov Institute”, pl. Akademika Kurchatova 1, Moscow 123182 (Russian Federation); Sulyanov, S.N.; Korotkov, N.Yu.; Rumyantseva, S.S.; Marchenko, I.V.; Funtov, K.O. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky av. 59, Moscow 119333 (Russian Federation); Vasiliev, A.L. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky av. 59, Moscow 119333 (Russian Federation); National Research Center “Kurchatov Institute”, pl. Akademika Kurchatova 1, Moscow 123182 (Russian Federation)

    2014-12-01

    Hollow microcapsules with the shell composed of biodegradable polyelectrolytes modified with the maghemite nanoparticles were fabricated by in situ synthesis. The nanoparticles were synthesized from the iron salt and the base directly on the capsule shells prepared by “layer by layer” technique. An average diameter of the capsule was about 6.7 μm while the average thickness of the capsule shell was 0.9 μm. XRD, HRTEM, Raman and Mössbauer spectroscopy data revealed that the iron oxide nanoparticles have the crystal structure of maghemite γ-Fe{sub 2}O{sub 3}. The nanoparticles were highly monodisperse with medium size of 7.5 nm. The Mössbauer spectroscopy data revealed that the nanoparticles have marked superparamagnetic behavior which was retained up to room temperature due to slow spin relaxation. Because of that, the microcapsules can be handled by an external magnetic field. Both these properties are important for target drug delivery. Based on the Mössbauer spectroscopy data, the spin blocking temperatures T{sub B} of about 90 K was found for the particles with size D ≤ 5 nm and T{sub B} ≈ 250 K for particles with D ≥ 6 nm. The anisotropy constants K were determined using the superparamagnetic approximation and in the low temperature approximation of collective magnetic excitation. - Highlights: • Hollow biodegradable microcapsules for target drug delivery • Modification of microcapsules by the maghemite nanoparticles by in situ synthesis • The nanoparticles are highly monodisperse with medium size of 7.5 nm. • Superparamagnetic properties of nanoparticles remain up to room temperature. • The spin blocking temperatures T{sub B} and the anisotropy constants K are determined.

  17. Soft nanomaterials analysed by in situ liquid TEM: Towards high resolution characterisation of nanoparticles in motion

    Directory of Open Access Journals (Sweden)

    Joseph P. Patterson

    2015-12-01

    Full Text Available In this article we present in situ transmission electron microscopy (TEM of soft, synthetic nanoparticles with a comparative analysis using conventional TEM methods. This comparison is made with the simple aim of describing what is an unprecedented example of in situ imaging by TEM. However, we contend the technique will quickly become essential in the characterisation of analogous systems, especially where dynamics are of interest in the solvated state. In this case, particles were studied which were obtained from the direct polymerisation of an oxaliplatin analogue, designed for an ongoing programme in novel chemotherapeutic delivery systems. The resulting nanoparticles provided sufficient contrast for facile imaging in situ, and point towards key design parameters that enable this new characterisation approach for organic nanomaterials. We describe the preparation of the synthetic nanoparticles together with their characterisation in liquid water. Finally, we provide a future perspective of this technique for the analysis of soft and dynamic nanomaterials and discussion the progress which needs to be made in order to bring in situ liquid TEM to its full potential.

  18. In Situ Gold Nanoparticle Gradient Formation in a 3D Meso- and Macroporous Polymer Matrix.

    Science.gov (United States)

    Penders, Jelle; Rajasekharan, Anand K; Hulander, Mats; Andersson, Martin

    2017-08-01

    Herein, the development and characterization of a 3D gradient structure of gold nanoparticles is described. The gradient of gold nanoparticles is made in situ in a macroporous nonionic block copolymer hydrogel matrix, through gold ion diffusion control. The polymer provides a matrix for diffusion of gold ions, acts as a template for controlling nanoparticle growth, and facilitates the in situ reduction of gold ions to gold nanoparticles. A clear gradient in gold nanoparticles is observed across the 3D space of the polymer matrix using scanning electron microscopy, fluorescence microscopy, atomic force microscopy, and thermogravimetric analysis. The particle gradient is further functionalized with both hydrophobic and hydrophilic groups via thiol-gold linkage to demonstrate the ability to form gradients with different chemical functionalities. Using additive manufacturing, the polymer can also be printed as a porous network with possible applications for 3D cell culturing in, e.g., biomaterials research. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. In situ reduction of as-prepared γ-Iron Oxide Nanoparticles

    DEFF Research Database (Denmark)

    Garbus, Pelle Gorm; Ahlburg, Jakob; Christensen, Mogens

    -ray diffraction measurement. The as-prepared maghemite nanoparticles were synthesized by the continuous decomposition of solutes in supercritical hydrothermal flow synthesis [3, 4]. The reagent used was ferric ammonium citrate (C6H8O7•xFe(III)•yNH3) that under hydrothermal flow synthesis decomposes into the γ......-197.4.Bremholm, M., M. Felicissimo, and B.B. Iversen, Time‐Resolved In Situ Synchrotron X‐ray Study and Large‐Scale Production of Magnetite Nanoparticles in Supercritical Water. Angewandte Chemie, 2009. 121(26): p. 4882-4885....

  20. Shape-and size-controlled Ag nanoparticles stabilized by in situ generated secondary amines

    International Nuclear Information System (INIS)

    Ramírez-Meneses, E.; Montiel-Palma, V.; Domínguez-Crespo, M.A.; Izaguirre-López, M.G.; Palacios-Gonzalez, E.; Dorantes-Rosales, H.

    2015-01-01

    Highlights: • Ag nanoparticles were generated from Ag amido complexes AgN i Pr 2 and AgN(SiMe 3 ) 2 . • Ag nanoparticles were stabilized by in situ generated HN i Pr 2 or HN(SiMe 3 ) 2 . • 1 or 5 equiv. of ethylenediamine as additional capping agent decreases the average size of the particles. • Ethylenediamine favor the formation of spherical particles. - Abstract: Silver amides such as AgN i Pr 2 and AgN(SiMe 3 ) 2 have been employed successfully as precursors for the yield synthesis of silver nanoparticles under mild conditions of dihydrogen gas reduction (2 atm) in organic media. Transmission electron microscopy (TEM) showed the formation of silver nanoparticles with FCC structure, variously sized from 26 to 35 nm for AgN i Pr 2 and from 14 to 86 nm for AgN(SiMe 3 ) 2 , the synthesis could take place in absence of added stabilizers due to the in situ formation of secondary amines from the reaction of dihydrogen gas with the amide ligands of the silver precursor. Indeed, the presence of HNR 2 (R = iPr 2 , N(SiMe 3 ) 2 ) on the surface of the nanoparticle was confirmed by spectroscopic means. Finally, the addition of ethylenediamine as additional capping agent allowed not only the control of the structural characteristics of the resulting Ag nanoparticles (well-dispersed with spherical shape), but that regarding the nanoparticle size as it inhibited overgrowth, limiting it to ca. 25 nm

  1. Shape-and size-controlled Ag nanoparticles stabilized by in situ generated secondary amines

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Meneses, E., E-mail: esther.ramirez@ibero.mx [Departamento de Ingeniería y Ciencias Químicas, Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Distrito Federal C.P. 01219 (Mexico); Montiel-Palma, V. [Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001 Col. Chamilpa, Cuernavaca, Morelos C.P. 62209 (Mexico); Domínguez-Crespo, M.A.; Izaguirre-López, M.G. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada-IPN, Unidad Altamira. Km 14.5 Carretera Tampico-Puerto Industrial, 89600 Altamira, Tamaulipas (Mexico); Palacios-Gonzalez, E. [Laboratorio de Microscopia de Ultra alta Resolución, Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas No. 152, C.P. 07730 México D.F. (Mexico); Dorantes-Rosales, H. [Departamento de Metalurgia, E.S.I.Q.I.E.-I.P.N., Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación. Gustavo A. Madero, C.P. 07738 México D.F. (Mexico)

    2015-09-15

    Highlights: • Ag nanoparticles were generated from Ag amido complexes AgN{sup i}Pr{sub 2} and AgN(SiMe{sub 3}){sub 2}. • Ag nanoparticles were stabilized by in situ generated HN{sup i}Pr{sub 2} or HN(SiMe{sub 3}){sub 2}. • 1 or 5 equiv. of ethylenediamine as additional capping agent decreases the average size of the particles. • Ethylenediamine favor the formation of spherical particles. - Abstract: Silver amides such as AgN{sup i}Pr{sub 2} and AgN(SiMe{sub 3}){sub 2} have been employed successfully as precursors for the yield synthesis of silver nanoparticles under mild conditions of dihydrogen gas reduction (2 atm) in organic media. Transmission electron microscopy (TEM) showed the formation of silver nanoparticles with FCC structure, variously sized from 26 to 35 nm for AgN{sup i}Pr{sub 2} and from 14 to 86 nm for AgN(SiMe{sub 3}){sub 2}, the synthesis could take place in absence of added stabilizers due to the in situ formation of secondary amines from the reaction of dihydrogen gas with the amide ligands of the silver precursor. Indeed, the presence of HNR{sub 2} (R = iPr{sub 2}, N(SiMe{sub 3}){sub 2}) on the surface of the nanoparticle was confirmed by spectroscopic means. Finally, the addition of ethylenediamine as additional capping agent allowed not only the control of the structural characteristics of the resulting Ag nanoparticles (well-dispersed with spherical shape), but that regarding the nanoparticle size as it inhibited overgrowth, limiting it to ca. 25 nm.

  2. A light-assisted in situ embedment of silver nanoparticles to prepare functionalized fabrics

    Directory of Open Access Journals (Sweden)

    Toh HS

    2017-11-01

    Full Text Available Her Shuang Toh,1 Roxanne Line Faure,2 Liyana Bte Mohd Amin,1 Crystal Yu Fang Hay,1 Saji George1,3 1Centre of Sustainable Nanotechnology, School of Chemical and Life Sciences, Nanyang Polytechnic, Singapore, Singapore; 2DUT Analyses Biologiques et Biochimiques, IUT Génie Biologique, Dijon, France; 3Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, Sainte-Anne-de-Bellevue, QC, Canada Abstract: This article presents a simple, one-step, in situ generation of silver nanoparticle-functionalized fabrics with antibacterial properties, circumventing the conventional, multistep, time-consuming methods. Silver nanoparticle formation was studied with a library of capping agents (branched polyethylenimine [BPEI] of molecular weight [Mw] 10,000 and 25,000, polyvinylpyrrolidone, polyethylene glycol, polyvinylalcohol and citrate mixed with silver nitrate. The mixture was then exposed to an assortment of light wavelengths (ultraviolet, infrared and simulated solar light for studying the light-assisted synthesis of nanoparticles. The formation of nanoparticles corresponded with the reducing capabilities of the polymers wherein BPEI gave the best response. Notably, the irradiation wavelengths had little effect on the formation of the nanoparticle when the total irradiation energy was kept constant. The feasibility of utilizing this method for in situ nanoparticle synthesis on textile fabrics (towel [100% cotton], gauze [100% cotton], rayon, felt [100% polyester] and microfiber [15% nylon, 85% polyester] was verified by exposing the fabrics soaked in an aqueous solution of 1% (w/v AgNO3 and 1% (w/v BPEI (Mw 25,000 to light. The formation of nanoparticles on fabrics and their retention after washing was verified using scanning electron microscopy and quantified by inductively coupled plasma optical emission spectrometry. The functional property of the fabric as an antibacterial surface was successfully demonstrated using

  3. In Situ Thermal Generation of Silver Nanoparticles in 3D Printed Polymeric Structures

    Directory of Open Access Journals (Sweden)

    Erika Fantino

    2016-07-01

    Full Text Available Polymer nanocomposites have always attracted the interest of researchers and industry because of their potential combination of properties from both the nanofillers and the hosting matrix. Gathering nanomaterials and 3D printing could offer clear advantages and numerous new opportunities in several application fields. Embedding nanofillers in a polymeric matrix could improve the final material properties but usually the printing process gets more difficult. Considering this drawback, in this paper we propose a method to obtain polymer nanocomposites by in situ generation of nanoparticles after the printing process. 3D structures were fabricated through a Digital Light Processing (DLP system by disolving metal salts in the starting liquid formulation. The 3D fabrication is followed by a thermal treatment in order to induce in situ generation of metal nanoparticles (NPs in the polymer matrix. Comprehensive studies were systematically performed on the thermo-mechanical characteristics, morphology and electrical properties of the 3D printed nanocomposites.

  4. Orientation relationship in WC-Co composite nanoparticles synthesized by in situ reactions

    Science.gov (United States)

    Wang, Xilong; Song, Xiaoyan; Liu, Xuemei; Liu, Xingwei; Wang, Haibin; Zhou, Cheng

    2015-04-01

    Using the nanoscale violet tungsten oxide as the tungsten source, the WC-Co composite powder was synthesized by the in situ reactions. The particle size of the WC-Co composite powder has a narrow distribution with the mean particle size below 100 nm, and the single composite particle has a nanocrystalline structure with a mean grain size smaller than 10 nm. The detailed characterizations of the nanoparticle microstructure reveal that the orientation relationship and coherence at the interfaces can form during the in situ reactions and further inherit in the consolidated cemented carbide bulk material. The favorable crystallographic characteristics of the WC-Co composite nanoparticles play a significant role in the enhancement of the mechanical properties of the prepared cemented carbide bulk material.

  5. In situ investigation of ordering phase transformations in FePt magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, James E., E-mail: j.wittig@vanderbilt.edu [Interdisciplinary Materials Science, Vanderbilt University, PMB 351683, 2301 Vanderbilt Place, Nashville, TN 37232 (United States); Bentley, James, E-mail: bentleyj48@gmail.com [Materials Science and Technology Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6376 (United States); Allard, Lawrence F., E-mail: allardlfjr@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6376 (United States)

    2017-05-15

    In situ high-resolution electron microscopy was used to reveal information at the atomic level for the disordered-to-ordered phase transformation of equiatomic FePt nanoparticles that can exhibit outstanding magnetic properties after transforming from disordered face-centered-cubic into the tetragonal L1{sub 0} ordered structure. High-angle annular dark-field imaging in the scanning transmission electron microscope provided sufficient contrast between the Fe and Pt atoms to readily monitor the ordering of the atoms during in situ heating experiments. However, during continuous high-magnification imaging the electron beam influenced the kinetics of the transformation so annealing had to be performed with the electron beam blanked. At 500 °C where the reaction rate was relatively slow, observation of the transformation mechanisms using this sequential imaging protocol revealed that ordering proceeded from (002) surface facets but was incomplete and multiple-domain particles were formed that contained anti-phase domain boundaries and anti-site defects. At 600 and 700 °C, the limitations of sequential imaging were revealed as a consequence of increased transformation kinetics. Annealing for only 5 min at 700 °C produced complete single-domain L1{sub 0} order; such single-domain particles were more spherical in shape with (002) facets. The in situ experiments also provided information concerning nanoparticle sintering, coalescence, and consolidation. Although there was resistance to complete sintering due to the crystallography of L1{sub 0} order, the driving force from the large surface-area-to-volume ratio resulted in considerable nanoparticle coalescence, which would render such FePt nanoparticles unsuitable for use as magnetic recording media. Comparison of the in situ data acquired using the protocol described above with parallel ex situ annealing experiments showed that identical behavior resulted in all cases. - Highlights: • HAADF STEM imaging reveals the

  6. Studying the Kinetics of Crystalline Silicon Nanoparticle Lithiation with In Situ Transmission Electron Microscopy

    KAUST Repository

    McDowell, Matthew T.

    2012-09-04

    In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Solvent-assisted in situ synthesis of cysteamine-capped silver nanoparticles

    Science.gov (United States)

    Oliva, José M.; Ríos de la Rosa, Julio M.; Sayagués, María J.; Sánchez-Alcázar, José A.; Merkling, Patrick J.; Zaderenko, Ana P.

    2018-03-01

    Silver nanoparticles offer a huge potential for biomedical applications owing to their exceptional properties and small size. Specifically, cysteamine-capped silver nanoparticles could form the basis for new anticancer therapies combining the cytotoxic effect of the silver core with the inherent antitumor activity of cysteamine, which inhibit cancer cell proliferation and suppress invasion and metastasis. In addition, the capability of the cysteamine coating monolayer to couple a variety of active principles and targeting (bio)molecules of interest proves key to the tailoring of this platform in order to exploit the pathophysiology of specific tumor types. Nevertheless, the chain length and conformational flexibility of cysteamine, together with its ability to attach to the surface of silver nanoparticles via both the thiol and the amine group, have made the in situ synthesis of these particles an especially challenging task. Herein we report a solvent-assisted in situ synthesis method that solves this problem. The obtained nanoparticles have been fully characterized by UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, electron diffraction measurement, high resolution transmission electron microscopy, scanning transmission electron microscopy, energy dispersive x-ray spectroscopy nanoanalysis, and dynamic light scattering measurement. Our synthesis method achieves extremely high yield and surface coating ratio, and colloidal stability over a wide range of pH values including physiological pH. Additionally, we have demonstrated that cysteamine-capped nanoparticles obtained by this method can be conjugated to an antibody for active targeting of the epidermal growth factor receptor, which plays an important role in the pathogenesis and progression of a wide variety of tumors, and induce cell death in human squamous carcinoma cells. We believe this method can be readily extended to combinations of noble

  8. In situ ultrasonic diagnostic of zeolite X crystallization with novel (hierarchical) morphology from coal fly ash.

    Science.gov (United States)

    Musyoka, Nicholas M; Petrik, Leslie F; Hums, Eric; Baser, Hasan; Schwieger, Wilhelm

    2014-02-01

    In this paper the applicability of an in situ ultrasonic diagnostic technique in understanding the formation process of zeolite X with a novel morphology was demonstrated. The complexity of the starting fly ash feedstock demands independent studies of the formation process for each type of zeolite since it is not known whether the crystallization mechanism will always follow the expected reaction pathway. The hierarchical zeolite X was noted to follow a solution phase-mediated crystallization mechanism which differs from earlier studies of the zeolite A formation process from unaged, clear solution extracted from fused fly ash. The use of the in situ ultrasonic monitoring system provided sufficient data points which enabled closer estimation of the time of transition from the nucleation to the crystal growth step. In order to evaluate the effect of temperature on the resulting in situ attenuation signal, synthesis at three higher temperatures (80, 90 and 94 °C) was investigated. It was shown, by the shift of the US-attenuation signal, that faster crystallization occurred when higher temperatures were applied. The novel hierarchical zeolite X was comprised of intergrown disc-like platelets. It was further observed that there was preferential growth of the disc-shaped platelets of zeolite X crystals in one dimension as the synthesis temperature was increased, allowing tailoring of the hierarchical morphology. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Applications of nanoparticles in cancer detection and diagnostic tool for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Venkatasalam, C.; Nagappan, A.

    2012-01-01

    Cancer nanotechnology is multidisciplinary area of science and technology. In recent days nano particles are used in medical field as diagnostic tools. It is highly precious and accurate measurement tools for detecting many disease. One of the broad application of cancer biology, for detecting molecular imaging, molecular diagnosis of cancer cells. In the present study deals with the nanoparticles are widely used for finding tumor as biomarker imaging for cancer detection and the nanoparticles are have important notice. An ample choice of materials may be used for construct nanoparticles that can cover for increase the capability of delivery or to provide unique structural and electrical properties for imaging. This exclusive properties are worn to several functional nanoparticles have already been demonstrated, including some clinically approved liposome drugs and metallic imaging agents. In early detection of heptocellular carcinoma, the metallic nanoparticles are vital role in the imaging technology. Several functions of nanoparticles that may eventually additional the understanding of producing imaging especially the darkening and enlarging of the images. These nanoparticles may be able to identify malignant cells by means of molecular detection, visualization of their location in the body by providing enhanced contrast in medical imaging technology, Through selective particle targeting and monitoring of identification of multiplied cells in different organs of the body. In the future prospective of medical field, the nanoparticles are having vital role for detecting cancer cells. (author)

  10. Rubber composite fibers containing silver nanoparticles prepared by electrospinning and in-situ chemical crosslinking

    Directory of Open Access Journals (Sweden)

    M. Tian

    2012-04-01

    Full Text Available Rubber composite fibers containing silver nanoparticles with high morphological stability were prepared through combination of electrospinning and in-situ chemical crosslinking. The composite fibers included those of Ag/polybutadiene rubber (BR, Ag/polyisobutylene-isoprene rubber (IIR, and Ag/silicon rubber (SiR. During the study, Ag nanoparticles (Ag NPs were first generated through reducing the Ag+ ions in rubber/N,N-dimethyformamide/tetrahydrofuran solutions upon ultraviolet-irradiation; subsequently, rubber composite fibers with uniform diameters from hundreds of nanometers to several micrometers were made by electrospinning the above solutions. The electrospinning was carried out with in-situ chemical crosslinking. The results indicated that chemical crosslinking during (and shortly after electrospinning was able to improve substantially the morphological stability of rubber fibers. As indicated by the results acquired from UV absorption spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope, Ag nanoparticles with sizes of 10~20 nm were uniformly dispersed in rubber fibers. It was believed that, in addition to the protection of polyvinyl pyrrolidone, a rapid solvent evaporation and limited motion space for a very fine fiber during electrospinning could prevent/mitigate the aggregation of Ag NPs, resulting in a very uniform dispersion. The electrospun Ag NPs/BR composite fibers made of the solution containing very low loading amount (3 wt% of AgNO3 demonstrated strong antimicrobial activity.

  11. Nanoparticles for biomedical imaging, therapy, and quantitative diagnostics

    Science.gov (United States)

    Yust, Brian G.

    Nanoparticles and nanomaterials are known to exhibit extraordinary characteristics and have a wide range of application which utilizes their unique properties. In particular, nanoparticles have shown great promise towards advancing the state of biological and biomedical techniques such as in vivo and in vitro imaging modalities, biosensing, and disease detection and therapy. Nanocrystalline hosts: NaYF4, KYF4, KGdF4, NaMF3, and KMF3 (M=Mg, Ba, Mn, Fe, Co, Ni, Cr) doped with rare earth ions have been synthesized by thermolysis, solvothermal, and hydrothermal methods. The morphology and spectroscopic properties have been thoroughly characterized. These nanoparticles (NP) are particularly useful for biomedical purposes since both the exciting and emitting wavelengths are in the near-infrared, where most tissues do not strongly absorb or scatter light. In vivo and in vitro imaging was performed with a 980 nm excitation source. Finally, NPs were conjugated with zinc phthalocyanine, a photosensitizer with a large absorption coefficient in the red and NIR regions, to illustrate the efficacy of these NPs as a platform for dual-mode infrared-activated imaging and photodynamic platforms. In addition, nonlinear optical nanomaterials, such as BaTiO3 and Ag@BaTiO3, were also synthesized and characterized. The nonlinear optical properties were investigated, and it is demonstrated that these nanoparticles can produce phase conjugate waves when used in a counterpropagating four wave mixing setup. The third order susceptibility is quantified using the z-scan technique, and the toxicity of these nanoparticles is also explored.

  12. Two stage tumor diagnostics based on hydroxyapatite nanoparticles with polymer corona

    Czech Academy of Sciences Publication Activity Database

    Lobaz, Volodymyr; Nový, Z.; Gurska, S.; Sakmár, M.; Kukleva, E.; Vlk, M.; Kozempel, J.; Petrík, M.; Hrubý, Martin

    2017-01-01

    Roč. 13, č. 1 (2017), s. 89 ISSN 1336-7242. [Zjazd chemikov /69./. 11.09.2017-15.09.2017, Horný Smokovec] R&D Projects: GA MZd(CZ) NV16-30544A Institutional support: RVO:61389013 Keywords : hydroxyapatite nanoparticles * radioactive labeling * tumor diagnostics Subject RIV: FD - Oncology ; Hematology

  13. Gold-manganese nanoparticles for targeted diagnostic and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Murph, Simona Hunyadi [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-11-10

    Imagine the possibility of non-invasive, non-radiation based Magnetic resonance imaging (MRI) in combating cardiac disease. Researchers at the Savannah River National Laboratory (SRNL) are developing a process that would use nanotechnology in a novel, targeted approach that would allow MRIs to be more descriptive and brighter, and to target specific organs. Researchers at SRNL have discovered a way to use multifunctional metallic gold-manganese nanoparticles to create a unique, targeted positive contrast agent. SRNL Senior Scientist Dr. Simona Hunyadi Murph says she first thought of using the nanoparticles for cardiac disease applications after learning that people who survive an infarct exhibit up to 15 times higher rate of developing chronic heart failure, arrhythmias and/or sudden death compared to the general population. Without question, nanotechnology will revolutionize the future of technology. The development of functional nanomaterials with multi-detection modalities opens up new avenues for creating multi-purpose technologies for biomedical applications.

  14. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    International Nuclear Information System (INIS)

    Tsai, Tsung-Ting; Shen, Shu-Wei; Chen, Chien-Fu; Cheng, Chao-Min

    2013-01-01

    A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h. (paper)

  15. Ex situ integration of iron oxide nanoparticles onto the exfoliated expanded graphite flakes in water suspension

    Directory of Open Access Journals (Sweden)

    Jović Nataša

    2014-01-01

    Full Text Available Hybrid structures composed of exfoliated expanded graphite (EG and iron oxide nanocrystals have been produced by an ex situ process. The iron oxide nanoparticles coated with meso-2,3-dimercaptosuccinic acid (DMSA, or poly(acrylic acid (PAA were integrated onto the exfoliated EG flakes by mixing their aqueous suspensions at room temperature under support of 1-ethyl-3-(3-dimethylaminopropylcarbodiimide (EDC and N-hydroxysuccin-nimide (NHS. EG flakes have been used both, naked and functionalized with branched polyethylenimine (PEI. Complete integration of two constituents has been achieved and mainteined stable for more than 12 months. No preferential spatial distribution of anchoring sites for attachement of iron oxide nanoparticles has been observed, regardless EG flakes have been used naked or functionalized with PEI molecules. The structural and physico-chemical characteristics of the exfoliated expanded graphite and its hybrids nanostructures has been investigated by SEM, TEM, FTIR and Raman techniques. [Projekat Ministarstva nauke Republike Srbije, br. 45015

  16. Stability of silver nanoparticle monolayers determined by in situ streaming potential measurements

    International Nuclear Information System (INIS)

    Morga, Maria; Adamczyk, Zbigniew; Oćwieja, Magdalena

    2013-01-01

    A silver particle suspension obtained by a chemical reduction was used in this work. Monolayers of these particles (average size 28 nm) on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverages, quantitatively determined by atomic force microscopy (AFM) and SEM, was regulated by adjusting the nanoparticle deposition time and the suspension concentration. The zeta potential of the monolayers was determined by streaming potential measurements carried out under in situ (wet) conditions. These measurements performed for various ionic strengths and pH were interpreted in terms of the three-dimensional (3D) electrokinetic model. The stability of silver monolayers was also investigated using streaming potential and the AFM methods. The decrease in the surface coverage of particles as a function of time and ionic strength varied between 10 −1 and 10 −4  M was investigated. This allowed one to determine the equilibrium adsorption constant K a and the binding energy of silver particles (energy minima depth). Energy minima depth were calculated that varied between −18 kT for I = 10 −1  M and −19 kT for I = 10 −4 for pH 5.5 and T = 298 K. Our investigations suggest that the interactions between surface and nanoparticles are controlled by the electrostatic interactions among ion pairs. It was also shown that the in situ electrokinetic measurements are in accordance with those obtained by more tedious ex situ AFM measurements. This confirmed the utility of the streaming potential method for direct kinetic studies of nanoparticle deposition/release processes.Graphical Abstract

  17. Superparamagnetic Bifunctional Bisphosphonates Nanoparticles: A Potential MRI Contrast Agent for Osteoporosis Therapy and Diagnostic

    Directory of Open Access Journals (Sweden)

    Y. Lalatonne

    2010-01-01

    Full Text Available A bone targeting nanosystem is reported here which combined magnetic contrast agent for Magnetic Resonance Imaging (MRI and a therapeutic agent (bisphosphonates into one drug delivery system. This new targeting nanoplatform consists of superparamagnetic γFe2O3 nanoparticles conjugated to 1,5-dihydroxy-1,5,5-tris-phosphono-pentyl-phosphonic acid (di-HMBPs molecules with a bisphosphonate function at the outer of the nanoparticle surface for bone targeting. The as-synthesized nanoparticles were evaluated as a specific MRI contrast agent by adsorption study onto hydroxyapatite and MRI measurment. The strong adsorption of the bisphosphonates nanoparticles to hydroxyapatite and their use as MRI T2∗ contrast agent were demonstrated. Cellular tests performed on human osteosarcoma cells (MG63 show that γFe2O3@di-HMBP hybrid nanomaterial has no citoxity effect in cell viability and may act as a diagnostic and therapeutic system.

  18. In-situ follow up of gold nano-particles nucleation-growth

    International Nuclear Information System (INIS)

    Abecassis, Benjamin

    2006-01-01

    In this thesis, we assess the formation mechanism of gold nanoparticles in situ in liquid media (homogeneous or in microemulsion) by small angle scattering techniques. The first part details several important concepts which are useful for an appropriate understanding of the rest of the thesis along with an overview of the literature on the subject. We then present results of time resolved synchrotron small angle X ray scattering and UV-visible experiment performed in situ during the formation of gold nanoparticles in organic solvent. We show that it is possible to follow the nucleation and growth of the particles in real time with a time resolution of a few hundreds milliseconds. We show that depending on the chemical nature of the ligand the nucleation and growth can be either simultaneous or separated in time. In the latter case, the growth is limited by surface reaction of the monomer at the particles surface. We also show that when the produced nanoparticles have an average radius larger than 5 nm, they self-assemble into ordered super-lattice which exhibit a cubic face center crystallographic structure. In a third part, by using a combination of complementary techniques we study water/oil/octyl-ammonium-octanoate microemulsions in the reverse micelles part of the phase diagram. The structure of these 'catanionic' microemulsions are revealed as a function of the water content, the temperature and the surface charge. The different observed topologies (sphere, rod-like or connected worm-like) and the phase transitions are compared to a recent theory which takes into account the curvature energy of the surfactant film. Finally, we show that these microemulsions can be used efficiently to synthesise gold nanoparticles. We show that the template effect, often cited to explain the formation of nanoparticles in reverse micelles is in our case not relevant. It is also noteworthy possible to separate and purify the as-produced nanoparticles by slightly

  19. In situ electromagnetic field diagnostics with an electron plasma in a Penning-Malmberg trap

    CERN Document Server

    Amole, C; Baquero-Ruiz, M.; Bertsche, W.; Butler, E.; Capra, A.; Cesar, C.L.; Charlton, M.; Deller, A.; Evetts, N.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M.C.; Gill, D.R.; Gutierrez, A.; Hangst, J.S.; Hardy, W.N.; Hayden, M.E.; Isaac, C.A.; Jonsell, S.; Kurchaninov, L.; Little, A.; Madsen, N.; McKenna, J.T.K.; Menary, S.; Napoli, S.C.; Olchanski, K.; Olin, A.; Pusa, P.; Rasmussen, C.; Robicheaux, F.; Sarid, E.; Silveira, D.M.; So, C.; Stracka, S.; Tharp, T.; Thompson, R.I.; van der Werf, D.P.; Wurtele, J.S.

    2014-01-01

    We demonstrate a novel detection method for the cyclotron resonance frequency of an electron plasma in a Penning-Malmberg trap. With this technique, the electron plasma is used as an in situ diagnostic tool for measurement of the static magnetic field and the microwave electric field in the trap. The cyclotron motion of the electron plasma is excited by microwave radiation and the temperature change of the plasma is measured non-destructively by monitoring the plasma's quadrupole mode frequency. The spatially-resolved microwave electric field strength can be inferred from the plasma temperature change and the magnetic field is found through the cyclotron resonance frequency. These measurements were used extensively in the recently reported demonstration of resonant quantum interactions with antihydrogen.

  20. In situ distributed diagnostics of flowable electrode systems: resolving spatial and temporal limitations.

    Science.gov (United States)

    Dennison, C R; Gogotsi, Y; Kumbur, E C

    2014-09-14

    In this study, we have developed an in situ distributed diagnostics tool to investigate spatial and temporal effects in electrochemical systems based on flowable electrodes. Specifically, an experimental approach was developed that enables spatially-resolved voltage measurements to be obtained in situ, in real-time. To extract additional data from these distributed measurements, an experimentally-parameterized equivalent circuit model with a new 'flow capacitor' circuit element was developed to predict the distributions of various system parameters during operation. As a case study, this approach was applied to investigate the behavior of the suspension electrodes used in an electrochemical flow capacitor under flowing and static conditions. The volumetric capacitance is reduced from 15.6 F ml(-1) to 1.1 F ml(-1) under flowing conditions. Results indicate that the majority of the charging in suspension electrodes occurs within ∼750 μm of the current collectors during flow, which gives rise to significant state-of-charge gradients across the cell, as well as underutilization of the available active material. The underlying cause of this observation is attributed to the relatively high electrical resistance of the slurry coupled with a stratified charging regime and insufficient residence time. The observations highlight the need to develop more conductive slurries and to design cells with reduced charge transport lengths.

  1. AREVA's innovative solutions for valve diagnostics and in-situ valve repair

    International Nuclear Information System (INIS)

    Damies, H.; Breitenberger, U.; Munoz, L.; Kostroun, F.

    2012-01-01

    Optimized maintenance strategies are a key aspect for safe and undisturbed plant operation. Innovative valve service solutions can support that in an efficient way. The ADAM®/SIPLUG® valve monitoring system allows full online monitoring of valves and actuators with automatic evaluation and assessment. Especially for safety-related and operation-related valves this provides valuable information on components condition to ensure proper function and contribute to optimization of maintenance strategies as well as effective maintenance performance. More than 25 years of experience in various plants worldwide show that application of ADAM®/SIPLUG® valve diagnostics solution leads to increased plant safety and availability. With the innovative AVARIS technology an in-situ valve repair is possible. It has the unique ability to conduct several steps in-situ, to maintain the sealing seat of gate or check valves. By applying AVARIS, the valve is restored in its original state, the system remains unchanged. Thus, all original documents remain valid and applicable. In comparison to previous procedures like cutting valves out of the pipeline and repairing hard facings or damaged seal seats in a separate workshop or alternatively replacement by a new valve body the new AVARIS technology avoids costs, risk and effort. (author)

  2. Solvent hydrophobicity induced complex coacervation of dsDNA and in situ formed zein nanoparticles.

    Science.gov (United States)

    Pandey, Pankaj Kumar; Kaushik, Priyanka; Rawat, Kamla; Aswal, V K; Bohidar, H B

    2017-10-04

    Zein, a predominantly hydrophobic protein, was sustained as a stable dispersion in ethanol-water (80 : 20, % (v/v)) binary solvent at room temperature (25 °C). Addition of aqueous dsDNA solution (1% (w/v)) to the above dispersion prepared with the protein concentration of C zein = 0.01-0.5% (w/v) caused a concomitant change in ethanol content from 14-35% (v/v), which in turn generated zein nanoparticles in situ of size 80-120 nm increasing with water content. The subsequent associative interaction between DNA (polyanion; 2000 bps) and the positively charged zein nanoparticles, (at pH = 4) was driven by Coulombic forces, and by the solvent hydrophobicity due to the ethanol content of the binary solvent. Experimentally, two interesting regions of interaction were observed from turbidity, zeta potential, particle sizing, and viscosity data: (i) for C zein nanoparticles of size 80 nm bind to dsDNA (primary complex) causing its condensation (apparent hydrodynamic size decreased from ≈2100 to 560 nm), and (ii) for 0.2% nanoparticles (>80 nm) were selectively bound to primary complexes to form partially charge neutralized interpolymer soluble complexes (secondary complexes), followed by complex coacervation. During this process, there was depletion of water in the vicinity of the nucleic acid, which was replaced by hydration provided by the ethanol-water binary solvent. Equilibrium coacervate samples were probed for their microstructure by small angle neutron scattering, and for their viscoelastic properties by rheology. The interplay of solvent hydrophobicity, electrostatic interaction, and zein nanoparticle size dependent charge neutralization had a commensurate effect on this hitherto unexplored coacervation phenomenon.

  3. Synthesis in situ of gold nanoparticles by a dialkynyl Fischer carbene complex anchored to glass surfaces

    International Nuclear Information System (INIS)

    Bertolino, María Candelaria; Granados, Alejandro Manuel

    2016-01-01

    Highlights: • Fischer carbene 1-W reacts via cycloaddition without Cu(I) with azide terminal surface. • This reaction on the surface is regioselective to internal triple bond of 1-W. • 1-W bound to glass surface produce AuNps in situ fixed to the surface. • This ability is independent of how 1-W is bonded to the surface. • This hybrid surface can be valuable as SERS substrate or in heterogeneous catalysis. - Abstract: In this work we present a detailed study of classic reactions such as “click reaction” and nucleophilic substitution reaction but on glass solid surface (slides). We used different reactive center of a dialkynylalcoxy Fischer carbene complex of tungsten(0) to be anchored to modified glass surface with amine, to obtain aminocarbene, and azide terminal groups. These cycloaddition reaction showed regioselectivity to internal triple bond of dialkynyl Fischer carbene complex without Cu(I) as catalyst. Anyway the carbene anchored was able to act as a reducing agent to produce in situ very stable gold nanoparticles fixed on surface. We showed the characterization of modified glasses by contact angle measurements and XPS. Synthesized nanoparticles were characterized by SEM, XPS, EDS and UV–vis. The modified glasses showed an important enhancement Raman-SERS. This simple, fast and robust method to create a polifunctional and hybrid surfaces can be valuable in a wide range of applications such as Raman-SERS substrates and other optical fields.

  4. In situ TEM investigations of mineral growth through oriented attachment of nanoparticles

    Science.gov (United States)

    Li, D.; Nielsen, M.; Lee, J. R.; Frandsen, C.; Banfield, J. F.; Kisailus, D.; De Yoreo, J.

    2012-12-01

    The growth of crystals through aggregation and coalescence of nanoparticles is now recognized as a widespread phenomenon in biomineral, biomimetic and natural systems, and during synthetic production of nanoparticles and nanowires. The resulting crystals often exhibit complex forms ranging from quasi-one-dimensional chains to 3D hierarchical and self-similar superstructures. Yet the final structure typically diffracts as a single crystal, implying that the primary particles aligned during growth. When coalignment is accompanied by coalescence, this growth process is often referred to as oriented attachment (OA). OA is now recognized as an important mechanism of crystal growth in many materials in the environment. However, the pathway by which OA occurs has not been established. Although the preservation of primary particle morphology and formation of twins and stacking faults at particle-particle boundaries strongly suggest a sequence of whole particle alignment followed by interface elimination, atom-by-atom reorientation via dislocation and grain-boundary migration after attachment are another potential mechanism. If indeed the primary particles align before attachment, the dynamics of that process and the forces that drive it have yet to be revealed. To achieve this understanding we are investigating crystal nucleation and oriented attachment in a number of systems, such as iron oxides and oxyhydroxide as well as titanium dioxide, through in situ and ex situ TEM. We performed high-resolution TEM using a fluid cell to directly observe oriented attachment of iron oxyhydroxide nanoparticles. The particles undergo continuous rotation and interaction until they find a perfect lattice match. A sudden jump to contact then occurs over less than 1 nanometer, followed by lateral atom-by-atom addition initiated at the contact point. Interface elimination proceeds at a rate consistent with the curvature dependence of the Gibbs free energy. Measured translational and

  5. Value of comparative genomic hybridization and fluorescence in situ hybridization for molecular diagnostics in multiple myeloma.

    Science.gov (United States)

    Liebisch, Peter; Viardot, Andreas; Bassermann, Nicole; Wendl, Christiane; Roth, Katrin; Goldschmidt, Hartmut; Einsele, Hermann; Straka, Christian; Stilgenbauer, Stephan; Döhner, Hartmut; Bentz, Martin

    2003-07-01

    Chromosomal abnormalities, such as 13q deletions, are emerging as important prognostic factors in multiple myeloma. Fluorescence in situ hybridization (FISH) using specific DNA probes is the technique most widely used for the determination of genomic aberrations in this disease. The utility of comparative genomic hybridization (CGH) for molecular diagnostics in plasma cell malignancies has not been systematically analysed. We investigated tumour samples of patients with multiple myeloma (n = 43) or plasma cell leukaemia (n = 3) using CGH and FISH with five DNA probes localized to chromosome bands 1p22, 6q21, 11q22-q23, 13q14 and 17p13. By CGH, the most frequent genomic changes were gains on chromosomes 1q, 9q and 11q, as well as losses on chromosomes 13q, 6q, Xp and Xq. By FISH, trisomy 11q was identified at a similar frequency to the 13q deletion (42%). Compared with FISH data, the sensitivity of CGH was 80.7% and the specificity was 97.5%. Thirty-two aberrations found by FISH were not identified by CGH, mostly as a result of the proportion of cells carrying the respective aberrations, or because of the limited spatial resolution of CGH. Our data indicate that, for clinical molecular diagnostics in multiple myeloma, FISH with a disease-specific DNA probe set is superior to CGH analysis.

  6. Synthesis of gold and silver nanoparticle S-ovalbumin protein conjugates by in situ conjugation process

    Science.gov (United States)

    Joshi, Deepti; Soni, R. K.

    2015-05-01

    Pure gold and silver nanoparticle (NP) generation and their conjugation with protein S-ovalbumin using in situ conjugation process have been reported. The in situ conjugation involves nanosecond pulse laser ablation of pure metal target in the protein S-ovalbumin solution. Transmission electron microscopy (TEM) and UV-Visible absorption results show decrease in mean NP size along with narrow particle size distribution on ablation in S-ovalbumin solution as compared to ablation in water for both Au and Ag NPs. Also, the NP size reduction was found to be dependent on the concentration of S-ovalbumin. For AuNPs, spherical NPs of mean size 4 nm with particle size distribution 2-6 nm were obtained at 300 nM S-ovalbumin concentration. Further, it has been observed that the resultant in situ-conjugated colloid gold and silver NP solutions were quite stable even in the presence of NaCl at physiological salt concentration (0.15 M). On post-laser irradiation (532 nm, 15 mJ) for 20 min, 9 nm red shift in surface plasmon resonance peak (SPR), along with increased broadening towards longer wavelength, was observed in the AuNPs-S-ovalbumin sample. Further increase in the time of irradiation showed shift in AuNPs-S-ovalbumin SPR towards lower wavelength. On laser irradiation (532 nm, 15 mJ) for 20 min, no significant change was observed in the line shape of the plasmon absorption band of the AgNPs-S-ovalbumin conjugate. FTIR spectra revealed that S-ovalbumin peptide backbone and secondary structure remain unchanged on laser irradiation during in situ conjugation process. Thus, integrity of S-ovalbumin does not get affected, and no degradation of S-ovalbumin takes place on laser-induced in situ conjugation. Raman results confirm that both Au and Ag NPs interact with S-ovalbumin via thiol-bearing cysteine residues of the disulfide bond.

  7. In situ forming interpenetrating hydrogels of hyaluronic acid hybridized with iron oxide nanoparticles.

    Science.gov (United States)

    Kheirabadi, Malihe; Shi, Liyang; Bagheri, Reza; Kabiri, Kourosh; Hilborn, Jöns; Ossipov, Dmitri A

    2015-11-01

    Four derivatives of hyaluronic acid (HA) bearing thiol (HA-SH), hydrazide (HA-hy), 2-dithiopyridyl (HA-SSPy), and aldehyde groups (HA-al) respectively were synthesized. Thiol and 2-dithiopyridyl as well as hydrazide and aldehyde make up two chemically orthogonal pairs of chemo-selective functionalities that allow in situ formation of interpenetrating (IPN) disulfide and hydrazone networks simultaneously upon the mixing of the above derivatives at once. The formation of IPN was demonstrated by comparing it with the formulations of the same total HA concentration but lacking one of the reactive components. The hydrogel composed of all four components was characterized by a larger elastic modulus than those of the control single networks (either disulfide or hydrazone) and the three component formulations gave the softest hydrogels. Moreover, a hydrazone cross-linkage was designed to contain a 1,2-diol fragment. This allowed us to partially disassemble one type of network in the IPN leaving another one unaffected. In particular, treatment of the IPN with either sodium periodate or dithiothreitol resulted in disassembly of the hydrazone and disulfide networks respectively and thus softening of the hydrogel. Contrarily, the single network hydrogels completely dissolved under the corresponding conditions. In corroboration with this, enzymatic degradation of the IPN by hyaluronidase was also substantially slower than the degradation of the single networks. In order to further improve the mechanical properties of the elaborated injectable IPN, it has been in situ hybridized with iron oxide nanoparticles (IONPs). The mesh size of the IPN was smaller than the size of the IONPs resulting in the retention of nanoparticles in the matrix under equilibrium swelling conditions. However, these nanoparticles were released upon enzymatic degradation suggesting their use as MRI tags for non-invasive tracking of the hydrogel material in vivo. Additionally, this injectable hybridized

  8. In-Situ sonosynthesis of Hedgehog-like nickel nanoparticles on polyester fabric producing magnetic properties.

    Science.gov (United States)

    Afshari, Sepideh; Montazer, Majid

    2018-04-01

    Recently, nano finishing of textiles is increasingly attracted many researchers to create new features on the products. Here a new fabric is introduced through simultaneous aminolysis and hydrolysis of polyester along with in-situ sonosynthesis of hedgehog shaped nickel nanoparticles on the fabric with magnetic properties. To do this, nickel sulfate, hydrazine hydrate, sodium hydroxide and polyvinylpyrrolidone (PVP) were used as a precursor, reducing agent, alkali and stabilizer respectively. Nickel sulfate was reduced to nickel nanoparticles with hydrazine hydrate at the adjusted pH with NaOH in the presence of PVP at 75 °C for 2 h. The polyester fabric was aminolyzed and hydrolyzed produced various functional groups on the fabric surface assisted nucleation and stabilization of nickel nanoparticles. The morphology, crystal phase, magnetic properties and chemical structure of the treated fabrics were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and energy dispersive X-ray spectroscopy (EDX). The optimized sample treated with 3.19 (mL) hydrazine hydrate, 3.99 (mL) sodium hydroxide and 0.41 (g) nickel sulfate showed reasonable saturation magnetization value of 4.5 emu g -1 . The treated fabrics showed no antibacterial and antifungal behavior indicating the safety of the products. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. In situ vaccination with cowpea mosaic virus nanoparticles suppresses metastatic cancer

    Science.gov (United States)

    Lizotte, P. H.; Wen, A. M.; Sheen, M. R.; Fields, J.; Rojanasopondist, P.; Steinmetz, N. F.; Fiering, S.

    2016-03-01

    Nanotechnology has tremendous potential to contribute to cancer immunotherapy. The ‘in situ vaccination’ immunotherapy strategy directly manipulates identified tumours to overcome local tumour-mediated immunosuppression and subsequently stimulates systemic antitumour immunity to treat metastases. We show that inhalation of self-assembling virus-like nanoparticles from cowpea mosaic virus (CPMV) reduces established B16F10 lung melanoma and simultaneously generates potent systemic antitumour immunity against poorly immunogenic B16F10 in the skin. Full efficacy required Il-12, Ifn-γ, adaptive immunity and neutrophils. Inhaled CPMV nanoparticles were rapidly taken up by and activated neutrophils in the tumour microenvironment as an important part of the antitumour immune response. CPMV also exhibited clear treatment efficacy and systemic antitumour immunity in ovarian, colon, and breast tumour models in multiple anatomic locations. CPMV nanoparticles are stable, nontoxic, modifiable with drugs and antigens, and their nanomanufacture is highly scalable. These properties, combined with their inherent immunogenicity and demonstrated efficacy against a poorly immunogenic tumour, make CPMV an attractive and novel immunotherapy against metastatic cancer.

  10. Durable antibacterial and UV protections of in situ synthesized zinc oxide nanoparticles onto cotton fabrics.

    Science.gov (United States)

    Shaheen, Th I; El-Naggar, Mehrez E; Abdelgawad, Abdelrahman M; Hebeish, A

    2016-02-01

    Herein we represent a new discovery based on amine material called hexamethyltriethylene tetramine (HMTETA). We have observed that when an aqueous solution of Zn(NO3)·6H2O was added to aqueous solution of HMTETA followed by shaking for a time, the colorless solution was converted to milky color under the alkaline medium provided by HMTETA prior to formation of uniform zinc oxide nanoparticles (ZnO NPs). The latter are in situ formed within the cotton fabrics without the support of capping or other stabilizing agents. Obviously, then, the new made of formation of ZnO NPs speaks of a single-stage process where cotton fabric is immersed in a prepared solution of the new precursors through which binding of ZnO NPs into the textile fabrics takes place. Textile fabrics are, indeed, used as a template, which is capable of maintaining the size and surface distribution of the as-synthesized nanoparticles in a uniform domain. It is also likely that nanoparticles is confined inside the fibril and microfibrils of the cotton fibers. World-class facilities have been employed to follow up the synthesis of ZnO NPs, their characterization and their application to confer, in particular, high durable antibacterial and UV protective function on cotton fabrics. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Chemical and Biological Sensing Using Diatom Photonic Crystal Biosilica With In-Situ Growth Plasmonic Nanoparticles

    Science.gov (United States)

    Kong, Xianming; Squire, Kenny; Li, Erwen; LeDuff, Paul; Rorrer, Gregory L.; Tang, Suning; Chen, Bin; McKay, Christopher P; Navarro-Gonzalez, Rafael

    2017-01-01

    In this paper, we described a new type of bioenabled nano-plasmonic sensors based on diatom photonic crystal biosilica with in-situ growth silver nanoparticles and demonstrated label-free chemical and biological sensing based on surface-enhanced Raman scattering (SERs) from complex samples. Diatoms are photosynthetic marine micro-organisms that create their own skeletal shells of hydrated amorphous silica, called frustules, which possess photonic crystal-like hierarchical micro-& nanoscale periodic pores. Our research shows that such hybrid plasmonic-biosilica nanostructures formed by cost-effective and eco-friendly bottom-up processes can achieve ultra-high limit of detection for medical applications, food sensing, water/air quality monitoring and geological/space research. The enhanced sensitivity comes from the optical coupling of the guided-mode resonance of the diatom frustules and the localized surface plasmons of the silver nanoparticles. Additionally, the nanoporous, ultra-hydrophilic diatom biosilica with large surface-to-volume ratio can concentrate more analyte molecules to the surface of the SERS substrates, which can help to detect biomolecules that cannot be easily adsorbed by metallic nanoparticles. PMID:27959817

  12. Note: An advanced in situ diagnostic system for characterization of electric propulsion thrusters and ion beam sources.

    Science.gov (United States)

    Bundesmann, C; Tartz, M; Scholze, F; Leiter, H J; Scortecci, F; Gnizdor, R Y; Neumann, H

    2010-04-01

    We present an advanced diagnostic system for in situ characterization of electric propulsion thrusters and ion beam sources. The system uses a high-precision five-axis positioning system with a modular setup and the following diagnostic tools: a telemicroscopy head for optical imaging, a triangular laser head for surface profile scanning, a pyrometer for temperature scanning, a Faraday probe for current density mapping, and an energy-selective mass spectrometer for beam characterization (energy and mass distribution, composition). The capabilities of our diagnostic system are demonstrated with a Hall effect thruster SPT-100D EM1.

  13. Development of polymer-coated nanoparticle imaging agents for diagnostic applications

    Science.gov (United States)

    Kairdolf, Brad A.

    Cancer is the second most common cause of death in the United States, with over 500,000 deaths expected this year. While significant progress has been made in the treatment and management of cancer, challenges remain because of the complexity and the heterogeneous nature of the disease. The improvement that has been seen in survival rates reflects advancements not only in treatment, but also in early stage detection and diagnostics for certain cancers. In particular, early stage detection and treatment of cancer before it has metastasized to other organs has resulted in a dramatic improvement in patient survival rates. One area of research that has shown considerable promise in further advancing diagnostics and early cancer detection is nanotechnology. Specifically, semiconductor and metal nanoparticles have great potential to provide advanced technology platforms for ultrasensitive and multiplexed detection of disease markers and probe disease on the molecular level. Because they are in the same size regime as biological molecules, these nanoparticles exhibit unique interactions with proteins, nucleic acids and other biomarkers of interest for detecting and diagnosing disease. However, high-quality nanoparticles are often unsuited for use in complex biological environments because of their coatings and surface chemistry. In this dissertation, we describe the design and development of polymer-coated nanoparticle imaging agents for use in blood, cell and tissue diagnostic applications. First, low-molecular weight, amphiphilic polymers, with hydrocarbon chains capable of noncovalent interactions with nanoparticle surface ligands and a hydrophilic backbone to render the nanoparticle water soluble, were synthesized and characterized for use in nanoparticle coating applications. We demonstrate that the hydrophobic and hydrophilic interactions between the nanoparticle surface, the amphiphilic polymer and the aqueous solvent were able to drive the coating and water

  14. In-situ reduced silver nanoparticles on populus fiber and the catalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Li, Miaomiao; Gong, Yumei, E-mail: ymgong@dlpu.edu.cn; Wang, Wenheng; Xu, Guangpeng; Liu, Yuanfa; Guo, Jing, E-mail: guojing8161@163.com

    2017-02-01

    Highlights: • A composite involved in in-situ chelating AgNPs on natural cellulose was prepared. • Polyamidoxime grafted from the cellulose adsorbed Ag+ which was reduced to AgNPs. • The composite exhibits excellent catalytic activity in reducing 4-nitrophenol. - Abstract: One kind of composites involved in silver nanoparticles (AgNPs) loading in-situ on natural populus fiber (PF) matrix was prepared by polyamidoxime (PAO) functionalized the cellulose fiber. In which PAO worked as trapping and stabilizing agents chelating silver ions and made it reduced in-situ to obtain AgNPs by borohydride at room temperature. The synthesized composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Moreover, the composites showed significant catalytic activity 1.87 s{sup −1} g{sup −1} and repeated usability more than 7 cycles in reducing 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) detected by UV–vis spectrophotometer in aqueous solution due to the surface-enhanced immobility and large amount of AgNPs. The natural cellulose fiber provides a green platform to react and support other noble metals for wide catalytic reactions.

  15. Antibacterial activity of silver nanoparticles synthesized In-situ by solution spraying onto cellulose.

    Science.gov (United States)

    Yan, Jinhua; Abdelgawad, Abdelrahman M; El-Naggar, Mehrez E; Rojas, Orlando J

    2016-08-20

    Spray technique was used for the adsorption of in-situ silver nanoparticles (AgNPs) onto and inside the surface of nano- and micro- fibrillar cellulose (NFC and MFC) as well as filter paper. The abundance of hydroxyl and carboxyl groups located in NFC and MFC are used to stabilize Ag ions (Ag(+)) which were then in-situ reduced to (AgNPs) by chemical or UV reduction. The surface characteristic features, elemental analysis, particle size as well as size distribution of the obtained MFC, NFC and filter paper loaded with AgNPs were characterized via field emission scanning electron microscopy connected to energy dispersive X-ray spectroscopy (FESEM- EDX) and transmission electron microscopy (TEM). The associated chemical changes after growth of AgNPs onto the cellulose substrates were assessed by fourier transform infra-red (FT-IR) while the thermal stability of such systems were investigated by thermogravimetrical analyses (TGA). The antibacterial properties of AgNPs loaded NFC, MFC and filter paper as well was investigated against Escherichia Coli. The resulted data indicate that the particle size was found to be 11 and 26nm for AgNPs nucleated on NFC and MFC-based papers respectively. The antibacterial activity of AgNPs loaded MFC exhibited higher antibacterial activity than that of AgNPs loaded NFC. Overall, the present research demonstrates facile and fast method for in-situ antibacterial AgNPs loading on cellulose substrates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets

    Energy Technology Data Exchange (ETDEWEB)

    Lavisse, L.; Jouvard, J.-M.; Girault, M.; Potin, V.; Andrzejewski, H.; Marco de Lucas, M. C.; Bourgeois, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Universite de Bourgogne, 9 Avenue A. Savary, BP 47870-21078 Dijon Cedex (France); Le Garrec, J.-L.; Carles, S.; Mitchell, J. B. A. [Institut de Physique de Rennes, UMR 6251 CNRS-Universite de Rennes 1, 35042 Rennes Cedex (France); Hallo, L. [CEA CESTA, 15 Avenue des Sablieres CS 60001, 33116 Le Barp Cedex (France); Perez, J. [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex (France); Decloux, J. [Kaluti System, Optique et Laser, Centre Scientifique d' Orsay, 91400 Orsay (France)

    2012-04-16

    Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.

  17. In Situ Synthesis and Deposition of Gold Nanoparticles with Different Morphologies on Glass and ITO Substrate by Ultrasonic Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    María de la Garza

    2013-01-01

    Full Text Available Gold nanoparticles were synthesized and deposited in situ by ultrasonic spray pyrolysis on glass and indium tin oxide (ITO substrates. This technique led to the formation of gold nanoparticles with different morphologies without the use of any capping agent. The gold nanoparticles deposited on glass substrate were obtained as nanospheres with an average particle size of 30 nm with some agglomerates; however, the nanoparticles deposited on ITO substrate were obtained with different morphologies, such as triangular nanoprisms, nanorods, nanocubes, and nanorhombus, with particle sizes between 40 and 100 nm. The ITO substrate influenced the morphology of the gold nanoparticles obtained due to changes in the deposition temperature, which also change the crystalline structure of the ITO film on the substrate.

  18. In situ Raman scattering study on a controllable plasmon-driven surface catalysis reaction on Ag nanoparticle arrays

    International Nuclear Information System (INIS)

    Dai, Z G; Xiao, X H; Zhang, Y P; Ren, F; Wu, W; Zhang, S F; Zhou, J; Jiang, C Z; Mei, F

    2012-01-01

    Control of the plasmon-driven chemical reaction for the transformation of 4-nitrobenzenethiol to p,p′-dimercaptoazobenzene by Ag nanoparticle arrays was studied. The Ag nanoparticle arrays were fabricated by means of nanosphere lithography. By changing the PS particle size, the localized surface plasmon resonance (LSPR) peaks of the Ag nanoparticle arrays can be tailored from 460 to 560 nm. The controlled reaction process was monitored by in situ surface-enhanced Raman scattering. The reaction can be dramatically influenced by varying the duration of laser exposure, Ag nanoparticle size, laser power and laser excitation wavelength. The maximum reaction speed was achieved when the LSPR wavelength of the Ag nanoparticle arrays matched the laser excitation wavelength. The experimental results reveal that the strong LSPR can effectively drive the transfer of the ‘hot’ electrons that decay from the plasmon to the reactants. The experimental results were confirmed by theoretical calculations. (paper)

  19. Implications of SPION and NBT nanoparticles upon in-vitro and in-situ biodegradation of LDPE film.

    Science.gov (United States)

    Kapri, Anil; Zaidi, M G H; Goel, Reeta

    2010-06-01

    Comparative influence of two nanoparticles viz. superparamagnetic iron oxide nanoparticles (SPION) and nanobarium titanate (NBT) was studied upon the in-vitro and in-situ low-density polyethylene (LDPE) biodegradation efficiency of a potential polymer-degrading microbial consortium. Supplementation of 0.01% concentration (w/v) of the nanoparticles in minimal broth significantly increased the bacterial growth, along with early onset of the exponential phase. Under in-vitro conditions, lambda-max shifts were quicker with nanoparticles and Fourier transform infrared spectroscopy (FTIR) illustrated significant changes in CH/CH2 vibrations, along with introduction of hydroxyl residues in the polymer backbone. Further, simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) reported multiple-step decomposition of LDPE degraded in the presence of nanoparticles. These findings were supported by scanning electron micrographs (SEM) which revealed greater dissolution of film surface in the presence of nanoparticles. Furthermore, progressive degradation of the film was greatly enhanced when it was incubated under soil conditions for 3 months with the nanoparticles. The study highlights the significance of bacteria-nanoparticle interactions which can dramatically influence key metabolic processes like biodegradation. The authors also propose the exploration of nanoparticles to influence various other microbial processes for commercial viabilities.

  20. Laser-produced Au nanoparticles as X-ray contrast agents for diagnostic imaging

    Czech Academy of Sciences Publication Activity Database

    Torrisi, L.; Restuccia, N.; Cuzzocrea, S.; Paterniti, I.; Ielo, I.; Pergolizzi, S.; Cutroneo, Mariapompea; Kováčik, L.

    2017-01-01

    Roč. 50, č. 1 (2017), s. 51-60 ISSN 0017-1557 R&D Projects: GA MŠk LM2015056; GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : Au nanoparticles * Laser * X-ray diagnostics * medical imaging * contrast medium Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.638, year: 2016

  1. In situ green synthesis and characterization of sericin-silver nanoparticle composite with effective antibacterial activity and good biocompatibility.

    Science.gov (United States)

    He, Huawei; Tao, Gang; Wang, Yejing; Cai, Rui; Guo, Pengchao; Chen, Liqun; Zuo, Hua; Zhao, Ping; Xia, Qingyou

    2017-11-01

    Silver nanoparticle has been widely applied to a variety of fields for its outstanding antimicrobial activity. However, the stability of silver nanoparticle limits its application under certain conditions. Thus, improving the stability of silver nanoparticle via biosynthesis is a promising shortcut to expand its application. Sericin from silkworm cocoon has good hydrophilicity, reaction activity, biocompatibility and biodegradability. In this study, we developed a novel, simple, one-step biosynthesis method to prepare sericin-silver nanoparticle composite in situ in solution. Sericin served as the reductant of silver ion, the dispersant and stabilizer of the prepared sericin-silver nanoparticle composite. Natural light was the only power source used to catalyze the synthesis of silver nanoparticle in situ in solution. The novel sericin-silver nanoparticle composite was characterized by ultraviolet-visible and fluorescence spectroscopy, X-ray diffraction, transmission electron microscopy and fourier transform infrared spectroscopy. The results showed silver nanoparticle could be synthesized through the reduction of AgNO 3 by the phenolic hydroxyl group of tyrosine residues of sericin under the catalysis of natural light. The synthesized silver nanoparticle had good crystalline, size distribution and long-term stability at room temperature. Light irradiation was essential for the preparation of sericin-silver nanoparticle composite. The antibacterial activity assay showed 25mg/L and 100mg/L were the minimum concentrations of sericin-silver nanoparticle composite required to inhibit the growth of Staphylococcus aureus and kill this bacterium, respectively. The cytotoxicity assay showed cell viability and cell growth were almost not affected by sericin-silver nanoparticle composite under the concentration of 25mg/L. Our study suggested the preparation of sericin-silver nanoparticle composite was environmentally friendly and energy conservation, and the prepared sericin

  2. In situ growth of capping-free magnetic iron oxide nanoparticles on liquid-phase exfoliated graphene

    NARCIS (Netherlands)

    Tsoufis, T.; Syrgiannis, Z.; Akhtar, N.; Prato, M.; Katsaros, F.; Sideratou, Z.; Kouloumpis, A.; Gournis, D.; Rudolf, P.

    2015-01-01

    We report a facile approach for the in situ synthesis of very small iron oxide nanoparticles on the surface of high-quality graphene sheets. Our synthetic strategy involved the direct, liquid-phase exfoliation of highly crystalline graphite (avoiding any oxidation treatment) and the subsequent

  3. In situ reduction of antibacterial silver ions to metallic silver nanoparticles on bioactive glasses functionalized with polyphenols

    International Nuclear Information System (INIS)

    Ferraris, S.; Miola, M.; Cochis, A.; Azzimonti, B.; Rimondini, L.; Prenesti, E.; Vernè, E.

    2017-01-01

    Highlights: • Gallic acid and natural polyphenols were grafted onto bioactive glasses. • Grafting ability was dependent on glass reactivity. • In situ reduction of silver nanoparticles was performed onto functionalized glasses. • Bioactive glasses decorated with silver nanoparticles showed antibacterial activity. - Abstract: The realization of surfaces with antibacterial properties due to silver nanoparticles loaded through a green approach is a promising research challenge of the biomaterial field. In this research work, two bioactive glasses have been doubly surface functionalized with polyphenols (gallic acid or natural polyphenols extracted from red grape skins and green tea leaves) and silver nanoparticles deposited by in situ reduction from a silver nitrate aqueous solution. The presence of biomolecules – showing reducing ability to directly obtain in situ metallic silver – and silver nanoparticles was investigated by means of UV–vis spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM). The antibacterial activity of the modified surfaces was tested against a multidrug resistant Staphylococcus aureus bacterial strain.

  4. In situ reduction of antibacterial silver ions to metallic silver nanoparticles on bioactive glasses functionalized with polyphenols

    Energy Technology Data Exchange (ETDEWEB)

    Ferraris, S., E-mail: sara.ferraris@polito.it [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy); Miola, M. [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy); Department of Health Sciences, Università del Piemonte Orientale UPO, Via Solaroli 17, 28100, Novara (Italy); Cochis, A.; Azzimonti, B.; Rimondini, L. [Department of Health Sciences, Università del Piemonte Orientale UPO, Via Solaroli 17, 28100, Novara (Italy); Prenesti, E. [Department of Chemistry, Università degli Studi di Torino, Via Pietro Giuria 7, Torino, 10125 (Italy); Vernè, E. [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy)

    2017-02-28

    Highlights: • Gallic acid and natural polyphenols were grafted onto bioactive glasses. • Grafting ability was dependent on glass reactivity. • In situ reduction of silver nanoparticles was performed onto functionalized glasses. • Bioactive glasses decorated with silver nanoparticles showed antibacterial activity. - Abstract: The realization of surfaces with antibacterial properties due to silver nanoparticles loaded through a green approach is a promising research challenge of the biomaterial field. In this research work, two bioactive glasses have been doubly surface functionalized with polyphenols (gallic acid or natural polyphenols extracted from red grape skins and green tea leaves) and silver nanoparticles deposited by in situ reduction from a silver nitrate aqueous solution. The presence of biomolecules – showing reducing ability to directly obtain in situ metallic silver – and silver nanoparticles was investigated by means of UV–vis spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM). The antibacterial activity of the modified surfaces was tested against a multidrug resistant Staphylococcus aureus bacterial strain.

  5. Dynamics of electrochemical lithiation/delithiation of graphene-encapsulated silicon nanoparticles studied by in-situ TEM.

    Science.gov (United States)

    Luo, Langli; Wu, Jinsong; Luo, Jiayan; Huang, Jiaxing; Dravid, Vinayak P

    2014-01-24

    The incorporation of nanostructured carbon has been recently reported as an effective approach to improve the cycling stability when Si is used as high-capacity anodes for the next generation Li-ion battery. However, the mechanism of such notable improvement remains unclear. Herein, we report in-situ transmission electron microscopy (TEM) studies to directly observe the dynamic electrochemical lithiation/delithiation processes of crumpled graphene-encapsulated Si nanoparticles to understand their physical and chemical transformations. Unexpectedly, in the first lithiation process, crystalline Si nanoparticles undergo an isotropic to anisotropic transition, which is not observed in pure crystalline and amorphous Si nanoparticles. Such a surprising phenomenon arises from the uniformly distributed localized voltage around the Si nanoparticles due to the highly conductive graphene sheets. It is observed that the intimate contact between graphene and Si is maintained during volume expansion/contraction. Electrochemical sintering process where small Si nanoparticles react and merge together to form large agglomerates following spikes in localized electric current is another problem for batteries. In-situ TEM shows that graphene sheets help maintain the capacity even in the course of electrochemical sintering. Such in-situ TEM observations provide valuable phenomenological insights into electrochemical phenomena, which may help optimize the configuration for further improved performance.

  6. Electrical imaging of subsurface nanoparticle propagation for in-situ groundwater remediation

    Science.gov (United States)

    Flores Orozco, Adrián; Gallistl, Jakob; Schmid, Doris; Micic Batka, Vesna; Bücker, Matthias; Hofmann, Thilo

    2017-04-01

    Application of nanoparticles has emerged as a promising in situ remediation technology for the remediation of contaminated groundwater, particularly for areas difficult to access by other remediation techniques. The performance of nanoparticle injections, as a foremost step within this technology, is usually assessed through the geochemical analysis of soil and groundwater samples. This approach is not well suited for a real-time monitoring, and often suffers from a poor spatio-temporal resolution and only provides information from areas close to the sampling points. To overcome these limitations we propose the application of non-invasive Induced Polarization (IP) imaging, a geophysical method that provides information on the electrical properties of the subsurface. The analysis of temporal changes in the electrical images allows tracking the propagation of the injected nanoparticle suspension and detection of the induced bio-geochemical changes in the subsurface. Here, we present IP monitoring results for data collected during the injection of Nano-Goethite particles (NGP) used for simulation of biodegradation of a BTEX plume (i.e., benzene, toluene, ethylbenzene, and xylene) at the Spolchemie II site, CZ. Frequency-domain IP measurements were collected parallel to the groundwater flow direction and centred on the NGP injection point. Pre-injection imaging results revealed high electrical conductivities (> 10 S/m) and negligible polarization effects in the BTEX-contaminated part of the saturated zone (below 5 m depth). The apparently contradictory observation - BTEX compounds are poor electrical conductors - can be explained by the release of carbonic acids (a metabolic by-product of the biodegradation of hydrocarbons), which leads to an increase of the electrical conductivity. Post-injection images revealed a significant decrease (> 50%) of the electrical conductivity, with even larger changes in the proximity of the injection points, most likely due to the

  7. Dynamic Probing of Nanoparticle Stability In Vivo: A Liposomal Model Assessed Using In Situ Microdialysis and Optical Imaging

    Directory of Open Access Journals (Sweden)

    Chien-Chung Jeng

    2011-01-01

    Full Text Available Nanoparticle-mediated drug delivery and controlled release has been a vigorous research area in contemporary nanomedicine. The in vivo stability of nanoparticle delivered on site is a prerequisite for the design of drug-controlled release by any means. In this study, the first methodology comprised of microdialysis and optical imaging to assess the liposome stability in vivo is reported. Macroscopically, we demonstrated the DPPG liposomes with negative surface charge fast accumulated in the rat liver upon their i.v. administration using optical imaging. Microscopically, the concurrent analysis of fluorescent molecules leaching from the liposomes, in situ sampled using microdialysis probe, provides the dynamic information of stability of DPPG liposomes locus in quo. The current combination of in situ microdialysis and optical imaging possesses a great potential for use as a platform technology to evaluate the nanoparticle stability and the bioavailability of drug payload released on targeted site in vivo.

  8. In situ reduction of antibacterial silver ions to metallic silver nanoparticles on bioactive glasses functionalized with polyphenols

    Science.gov (United States)

    Ferraris, S.; Miola, M.; Cochis, A.; Azzimonti, B.; Rimondini, L.; Prenesti, E.; Vernè, E.

    2017-02-01

    The realization of surfaces with antibacterial properties due to silver nanoparticles loaded through a green approach is a promising research challenge of the biomaterial field. In this research work, two bioactive glasses have been doubly surface functionalized with polyphenols (gallic acid or natural polyphenols extracted from red grape skins and green tea leaves) and silver nanoparticles deposited by in situ reduction from a silver nitrate aqueous solution. The presence of biomolecules - showing reducing ability to directly obtain in situ metallic silver - and silver nanoparticles was investigated by means of UV-vis spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM). The antibacterial activity of the modified surfaces was tested against a multidrug resistant Staphylococcus aureus bacterial strain.

  9. In situ electron beam irradiated rapid growth of bismuth nanoparticles in bismuth-based glass dielectrics at room temperature

    International Nuclear Information System (INIS)

    Singh, Shiv Prakash; Karmakar, Basudeb

    2011-01-01

    In this study, in situ control growth of bismuth nanoparticles (Bi 0 NPs) was demonstrated in bismuth-based glass dielectrics under an electron beam (EB) irradiation at room temperature. The effects of EB irradiation were investigated in situ using transmission electron microscopy (TEM), selected-area electron diffraction and high-resolution transmission electron microscopy. The EB irradiation for 2–8 min enhanced the construction of bismuth nanoparticles with a rhombohedral structure and diameter of 4–9 nm. The average particle size was found to increase with the irradiation time. Bismuth metal has a melting point of 271 °C and this low melting temperature makes easy the progress of energy induced structural changes during in situ TEM observations. This is a very useful technique in nano-patterning for integrated optics and other applications.

  10. Synthesis of mesoporous zeolite catalysts by in situ formation of carbon template over nickel nanoparticles

    DEFF Research Database (Denmark)

    Abildstrøm, Jacob Oskar; Kegnæs, Marina; Hytoft, Glen

    2016-01-01

    A novel synthesis procedure for the preparation of the hierarchical zeolite materials with MFI structure based on the carbon templating method with in situ generated carbon template is presented in this study. Through chemical vapour deposition of coke on nickel nanoparticles supported on silica...... oxide, a carbon-silica composite is obtained and exploited as a combined carbon template/silica source for zeolite synthesis. This approach has several advantages in comparison with conventional carbon templating methods, where relatively complicated preparative strategies involving multistep...... impregnation procedures and rather expensive chemicals are used. Removal of the carbon template by combustion results in zeolite single crystals with intracrystalline pore volumes between 0.28 and 0.48 cm3/g. The prepared zeolites are characterized by XRD, SEM, TEM and physisorption analysis. The isomerization...

  11. Preparation of cellulose composites with in situ generated copper nanoparticles using leaf extract and their properties.

    Science.gov (United States)

    Sadanand, V; Rajini, N; Varada Rajulu, A; Satyanarayana, B

    2016-10-05

    In the present work, copper nanoparticles (CuNPs) were in situ generated in cellulose matrix using Ocimum sanctum leaf extract as a reducing agent and aq. CuSO4 solution by diffusion process. Some CuNPs were also formed outside the film in the solution which were separated and viewed by Transmission electron microscope and Scanning electron microscope (SEM). The composite films showed good antibacterial activity against Escherichia coli bacteria when the CuNPs were generated using higher concentrated aq. CuSO4 solutions. The cellulose, matrix and the composite films were characterized by Fourier transform infrared spectroscopic, X-ray diffraction, thermogravimetric analysis and SEM techniques. The tensile strength of the composite films was lower than that of the matrix but still higher than the conventional polymers like polyethylene and polypropylene used for packaging applications. These biodegradable composite films can be considered for packaging and medical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. In situ synthesis of Ag nanoparticles-graphene oxide nanocomposites with strong SERS activity

    Science.gov (United States)

    Shi, Zengliang; Hao, Xiaolong; Xu, Chunxiang

    2018-01-01

    Without any capping agents or multistep process, a simple and green method for in situ synthesis of the Ag nanoparticles-graphene oxide sheets (Ag NPs-GO) nanocomposites was proposed. The Ag NPs were well-distributed on the surface of the GO sheets with a uniform size. The formation mechanism of the resulting nanocomposites was discussed. The presence of Ag NPs enhanced the Raman signal of GO in the resulting nanocomposites with an enhancement factor (EF) of 43. The resulting nanocomposites exhibited strong surface-enhanced Raman scattering (SERS) activity toward rhodamine 6G (R6G) with an EF of 1.4 × 107. The synergistic effects of the R6G molecules adsorbed on GO sheets and the coupled EM field caused by the Ag NPs lead to the significant SERS enhancement. This result makes the resulting Ag NPs-GO nanocomposites a more promising SERS substrate.

  13. In-situ decorated gold nanoparticles on polyaniline with enhanced electrocatalysis toward dopamine

    International Nuclear Information System (INIS)

    Wang, A.-J.; Feng, J.-J.; Xi, J.-L.; Dong, W.-J.; Li, Y.-F.

    2010-01-01

    Gold nanoparticles were in-situ decorated on top of a polyaniline film (GNPs-PANI) via the direct electroreduction of the adsorbed AuCl 4 - ions on a glassy carbon electrode that previously was coated with PANI by electropolymerization. The GNPs-PANI composite and the performance of the resultant sensors were investigated in some detail. The sensor was applied to the oxidation of dopamine (DA) with improved catalytic activity. Its catalytic current showed wide linear response toward dopamine ranging from 3 to 115 μM, with a low detection limit of 0. 8 μM (S/N=3). In addition, the sensor exhibits easy-operation, fast response to dopamine, as well as excellent reproducibility and stability. (author)

  14. Environmentally friendly procedure for in-situ coating of regenerated cellulose fibres with silver nanoparticles.

    Science.gov (United States)

    Pivec, Tanja; Hribernik, Silvo; Kolar, Mitja; Kleinschek, Karin Stana

    2017-05-01

    This study introduces a novel green in-situ procedure for introduction of silver nanoparticles (Ag NPs) on and into cellulose fibres in a three-stage process. First-stage of the process includes the activation of cellulose fibres in alkaline solution, followed by reduction of silver nitrate to Ag NPs in the second stage, while the last stage of process involves washing and neutralization of fibres. Efficiency of the method towards incorporation of silver particles into the fibres' internal structure was characterized; the coatings' morphology and determination of spatial presence of Ag particles were imagining by the scanning electron microscopy and accompanying energy dispersive x-ray spectroscopy analysis; prepared fibres have superior durability of particles' coating against washing and excellent antimicrobial activity even after 20 washing cycles. Additionally, the water retention of silver treated fibres was improved, while the mechanical properties were not significantly impaired. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Fluorescent in situ hybridization (FISH as a diagnostic tool for Williams-Beuren syndrome

    Directory of Open Access Journals (Sweden)

    Deise Helena de Souza

    2007-01-01

    Full Text Available Fluorescent in situ hybridization (FISH with commercial probes covering the elastin gene (ELN was used to determine the frequency of the 7q11.23 deletion in 18 children clinically diagnosed with Williams-Beuren syndrome (WBS. A de novo deletion was detected in 15 of the children (83%. Diagnostic investigation for WBS started late in childhood (median = 5.8 years. All the children showed facial features typical of the syndrome, mental retardation and developmental delay. Over-friendliness was observed in the majority of cases. Clinodactyly of the 5th finger (n = 13, cardiovascular disease (n = 9, loquacity (n = 9, low birthweight (n = 8, and failure to thrive (n = 9 were observed only in those children with the deletion. Respiratory problems (n = 9, though not previously reported in the literature, was a common finding in the group studied. Our results confirmed that FISH is useful in identifying 7q11.23 deletions in cases of WBS. Clinical manifestations were more evident in the deletion-positive children.

  16. The CORA dataset: validation and diagnostics of in-situ ocean temperature and salinity measurements

    Directory of Open Access Journals (Sweden)

    C. Cabanes

    2013-01-01

    Full Text Available The French program Coriolis, as part of the French operational oceanographic system, produces the COriolis dataset for Re-Analysis (CORA on a yearly basis. This dataset contains in-situ temperature and salinity profiles from different data types. The latest release CORA3 covers the period 1990 to 2010. Several tests have been developed to ensure a homogeneous quality control of the dataset and to meet the requirements of the physical ocean reanalysis activities (assimilation and validation. Improved tests include some simple tests based on comparison with climatology and a model background check based on a global ocean reanalysis. Visual quality control is performed on all suspicious temperature and salinity profiles identified by the tests, and quality flags are modified in the dataset if necessary. In addition, improved diagnostic tools have been developed – including global ocean indicators – which give information on the quality of the CORA3 dataset and its potential applications. CORA3 is available on request through the MyOcean Service Desk (http://www.myocean.eu/.

  17. Diagnostics of the Tropical Tropopause Layer from in-situ observations and CCM data

    Directory of Open Access Journals (Sweden)

    C. M. Volk

    2009-12-01

    Full Text Available A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM data to characterize the vertical structure of the Tropical Tropopause Layer (TTL. The diagnostics are based on vertical tracer profiles and relative vertical tracer gradients, using tropopause-referenced coordinates, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS.

    Observations were obtained during four tropical campaigns performed from 1999 to 2006 with the research aircraft Geophysica and have been compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL (~500 m allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data.

    The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone and carbon monoxide gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified by their different chemical composition.

    The joint analysis and comparison of observed and modelled data allows to state that the model can represent the background TTL structure and its seasonal variability rather accurately. The model

  18. Toward an in-situ analytics and diagnostics framework for earth system models

    Science.gov (United States)

    Anantharaj, Valentine; Wolf, Matthew; Rasch, Philip; Klasky, Scott; Williams, Dean; Jacob, Rob; Ma, Po-Lun; Kuo, Kwo-Sen

    2017-04-01

    , atmospheric rivers, blizzards, etc. It is evident that ESMs need an in-situ framework to decouple the diagnostics and analytics from the prognostics and physics computations of the models so that the diagnostic computations could be performed concurrently without limiting model throughput. We are designing a science-driven online analytics framework for earth system models. Our approach is to adopt several data workflow technologies, such as the Adaptable IO System (ADIOS), being developed under the U.S. Exascale Computing Project (ECP) and integrate these to allow for extreme performance IO, in situ workflow integration, science-driven analytics and visualization all in a easy to use computational framework. This will allow science teams to write data 100-1000 times faster and seamlessly move from post processing the output for validation and verification purposes to performing these calculations in situ. We can easily and knowledgeably envision a near-term future where earth system models like ACME and CESM will have to address not only the challenges of the volume of data but also need to consider the velocity of the data. The earth system model of the future in the exascale era, as they incorporate more complex physics at higher resolutions, will be able to analyze more simulation content without having to compromise targeted model throughput.

  19. Synthesis of calcium peroxide nanoparticles as an innovative reagent for in situ chemical oxidation.

    Science.gov (United States)

    Khodaveisi, J; Banejad, H; Afkhami, A; Olyaie, E; Lashgari, S; Dashti, R

    2011-09-15

    Chemical oxidation is one of the many different methods of site remediation that has emerged lately as an alternative method to traditional techniques. According to this research calcium peroxide is suitable choice for contaminant biodegradation in soil and ground water but speed of oxidation reaction between calcium peroxide and contaminant is slow. Synthesis of calcium peroxide in nano size by increased ratio of surface to volume can increase the speed of reaction and solve the problem. We have developed a simple surface modification technique to avoid irreversible agglomeration of calcium peroxide nanoparticles. The technique is based on hydrolysis-precipitation procedure, using CaCl(2) as a precursor. Polyethylene glycol 200 (PEG200) is used as a surface modifier. CaO(2) was identified and studied by characterization techniques, including XRD and TEM. The results indicate the ability of this method for synthesis of new reagent in nano size and improve quality of in situ chemical oxidation. Size determination by TEM image indicates the size of calcium peroxide nanoparticles approximately 15-25 nm. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. In situ biodegradable crosslinking of cationic oligomer coating on mesoporous silica nanoparticles for drug delivery.

    Science.gov (United States)

    Wang, Yifeng; Wang, Jine; Yang, Yang; Sun, Yi; Yuan, Yuan; Li, Yulin; Liu, Changsheng

    2017-05-01

    Although layer-by-layer assembly using anionic and cationic polymer has been a popular way to develop core-shell nanoparticles, the strong electrostatic interactions may limit shell degradability, thus hampering their application as a platform for controlled therapeutic delivery. In this study, we demonstrate a simple approach to developing mesoporous nanohybrids via a process of pre-drug loading (using doxorubicin (DOX) as a model drug) into mesoporous silica nanoparticles (MSN), followed by surface functionalization with a kind of cationic oligomer (low molecular weight polyethylene imine, LPEI) and in situ crosslinking by degradable N,N'-bis(acryloyl)cystamine (BAC). The presence of LPEI shell affords the nanohybrids with charge-reversal ability, which means that the acidic tumor extracellular microenvironment can transform the negative surface charge at neutral conditions into positive-charged ones. The nanohybrids displayed a pH- and redox-dual sensitivity in DOX release under conditions that mimic intracellular reductive conditions and acidic tumor microenvironments. The nanohybrids can be effectively internalized into A549 cells (a carcinomic human alveolar basal epithelial cell line), resulting in a high DOX intracellular accumulation and an improved anticancer cytotoxicity when compared with free DOX, suggesting their high potential as a new platform for therapeutic delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Combined synthesis and in situ coating of nanoparticles in the gas phase

    International Nuclear Information System (INIS)

    Laehde, Anna; Raula, Janne; Kauppinen, Esko I.

    2008-01-01

    Combined gas phase synthesis and coating of sodium chloride (NaCl) and lactose nanoparticles has been developed using an aerosol flow reactor. Nano-sized core particles were produced by the droplet-to-particle method and coated in situ by the physical vapour deposition of L-leucine vapour. The saturation of L-leucine in the reactor determined the resulting particle size and size distribution. In general, particle size increased with the addition of L-leucine and notable narrowing of the core particle size distribution was observed. In addition, homogeneous nucleation of the vapour, i.e. formation of pure L-leucine particles, was observed depending on the saturation conditions of L-leucine as well as the core particle characteristics. The effects of core particle properties, i.e. size and solid-state characteristics, on the coating process were studied by comparing the results for coated NaCl and lactose particles. During deposition, L-leucine formed a uniform coating on the surface of the core particles. The coating stabilised the nanoparticles and prevented the sintering of particles during storage.

  2. Characterization of Silver Nanoparticle In Situ Synthesis on Porous Sericin Gel for Antibacterial Application

    Directory of Open Access Journals (Sweden)

    Gang Tao

    2016-01-01

    Full Text Available Sericin from Bombyx mori cocoon has good hydrophilicity, reaction activity, biocompatibility, and biodegradability, which has shown great potentials for biomedical materials. Here, an ultraviolet light-assisted in situ synthesis approach is developed to immobilize silver nanoparticles on the surface of sericin gel. The amount of silver nanoparticles immobilized on the surface of sericin gel could be regulated by the irradiation time. The porous structure and property of sericin gel were not affected by the modification of AgNPs, as evidenced by the observation of scanning electron microscopy, X-ray diffractometry, and Fourier transform infrared spectroscopy. Differential scanning calorimetry analysis showed that the modification of AgNPs increased the thermal stability of sericin gel. The growth curve of bacteria and inhibition zone assays suggested that the sericin gel modified with AgNPs had good antimicrobial activities against both Gram-negative and Gram-positive bacteria. This novel sericin has shown a great potential for biomedical purpose.

  3. A dispenser-reactor apparatus applied for in situ XAS monitoring of Pt nanoparticle formation.

    Science.gov (United States)

    Boita, Jocenir; Castegnaro, Marcus Vinicius; Alves, Maria do Carmo Martins; Morais, Jonder

    2015-05-01

    In situ time-resolved X-ray absorption spectroscopy (XAS) measurements collected at the Pt L3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser-reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst followed by a slow growth and stabilization of NPs. Subsequently, the synthesized Pt NPs were supported on activated carbon and characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The supported Pt NPs remained in the metallic chemical state and with a reduced size, presenting slight lattice parameter contraction in comparison with the bulk Pt values.

  4. In situ effects of titanium dioxide nanoparticles on community structure of freshwater benthic macroinvertebrates.

    Science.gov (United States)

    Jovanović, Boris; Milošević, Djuradj; Piperac, Milica Stojković; Savić, Ana

    2016-06-01

    For the first time in the current literature, the effect of titanium dioxide (TiO2) nanoparticles on the community structure of macroinvertebrates has been investigated in situ. Macroinvertebrates were exposed for 100 days to an environmentally relevant concentration of TiO2 nanoparticles, 25 mg kg(-1) in sediment. Czekanowski's index was 0.61, meaning 39% of the macroinvertebrate community structure was affected by the TiO2 treatment. Non-metric multidimensional scaling (NMDS) visualized the qualitative and quantitative variability of macroinvertebrates at the community level among all samples. A distance-based permutational multivariate analysis of variance (PERMANOVA) revealed the significant effect of TiO2 on the macroinvertebrate community structure. The indicator value analysis showed that the relative frequency and abundance of Planorbarius corneus and Radix labiata were significantly lower in the TiO2 treatment than in the control. Meanwhile, Ceratopogonidae, showed a significantly higher relative frequency and abundance in the TiO2 treatment than in the control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. In-situ fabrication of cobalt oxide / sulphide mixed phase nanoparticles in Polyphenylenesulphide matrix

    Directory of Open Access Journals (Sweden)

    Narendra Rumale

    2013-03-01

    Full Text Available A novel approach for the in-situ fabrication of combined cobalt oxide / sulphide nanoparticles in sulphur containing polymer polyphenylenesulphide (PPS by polymer inorganic solid-solid reaction technique is reported here. At present, there is considerable interest in polymer-metal chalcogenides / oxides based nano-composites on account of their optical, magnetic, electronic and catalytic properties. We have demonstrated the suitability of solid-solid reaction methodology by reacting commonly available cobalt precursors with engineering thermoplastic PPS. The cobalt precursor was reacted with PPS in 1:1, 1:5, 1:10, and 1:15 molar ratios, respectively, by heating the mixture at the melting temperature of the polymer (285 ºC for six hours. The resultant products were characterized by X-ray diffractometry (XRD, Field-emission scanning electron microscopy (FESEM, Thermogravimetric analysis (TGA, Differential scanning calorimetry (DSC, Diffuse reflectance spectroscopy (DRS techniques and High resolution transmission electron microscope (HRTEM. The shift in melting temperature of PPS was observed. Increase in absorption peak is observed in the range of 320 to 370 nm with the increase in PPS concentration. Resultant nanoparticles of cobalt sulphide and cobalt oxide embedded in the PPS matrix showed spherical and distorted rod like morphology.

  6. Synthesis in situ of gold nanoparticles by a dialkynyl Fischer carbene complex anchored to glass surfaces

    Science.gov (United States)

    Bertolino, María Candelaria; Granados, Alejandro Manuel

    2016-10-01

    In this work we present a detailed study of classic reactions such as ;click reaction; and nucleophilic substitution reaction but on glass solid surface (slides). We used different reactive center of a dialkynylalcoxy Fischer carbene complex of tungsten(0) to be anchored to modified glass surface with amine, to obtain aminocarbene, and azide terminal groups. These cycloaddition reaction showed regioselectivity to internal triple bond of dialkynyl Fischer carbene complex without Cu(I) as catalyst. Anyway the carbene anchored was able to act as a reducing agent to produce in situ very stable gold nanoparticles fixed on surface. We showed the characterization of modified glasses by contact angle measurements and XPS. Synthesized nanoparticles were characterized by SEM, XPS, EDS and UV-vis. The modified glasses showed an important enhancement Raman-SERS. This simple, fast and robust method to create a polifunctional and hybrid surfaces can be valuable in a wide range of applications such as Raman-SERS substrates and other optical fields.

  7. In situ environmental transmission electron microscope investigation of NiGa nanoparticle synthesis

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Duchstein, Linus Daniel Leonhard; Elkjær, Christian Fink

    2011-01-01

    detailed Environmental Transmission Electron Microscope (ETEM) investigations of synthesis of NiGa nanoparticles on a thin film support. Samples were prepared by dissolving Ni(NO3)2 and Ga(NO3)3 in a Ni:Ga ratio of 5:3 in millipore water. The solution was subsequently dispersed on transmission electron...... have predicted a nickel gallium alloy to be active for this reaction [1]. NiGa catalysts prepared by incipient wetness impregnation on a high surface area silica support (Saint-Gobain NorPro), using a solution of nickel and gallium nitrates have shown very promising results [2]. This work presents...... microscope (TEM) sample grids. The sample grid was then mounted in a TEM heating holder and inserted in a FEI Titan ETEM with imaging Cs corrector as well as facilities for in situ gas reactions [3]. The ETEM was operated at 300 kV. The synthesis was performed in situ in a H2 flow of 2 Nml/min at a pressure...

  8. Synthesis of gold and silver nanoparticle S-ovalbumin protein conjugates by in situ conjugation process

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Deepti, E-mail: deeptimishrajoshi@gmail.com; Soni, R. K. [Indian Institute of Technology Delhi, Physics Department (India)

    2015-05-15

    Pure gold and silver nanoparticle (NP) generation and their conjugation with protein S-ovalbumin using in situ conjugation process have been reported. The in situ conjugation involves nanosecond pulse laser ablation of pure metal target in the protein S-ovalbumin solution. Transmission electron microscopy (TEM) and UV–Visible absorption results show decrease in mean NP size along with narrow particle size distribution on ablation in S-ovalbumin solution as compared to ablation in water for both Au and Ag NPs. Also, the NP size reduction was found to be dependent on the concentration of S-ovalbumin. For AuNPs, spherical NPs of mean size 4 nm with particle size distribution 2–6 nm were obtained at 300 nM S-ovalbumin concentration. Further, it has been observed that the resultant in situ-conjugated colloid gold and silver NP solutions were quite stable even in the presence of NaCl at physiological salt concentration (0.15 M). On post-laser irradiation (532 nm, 15 mJ) for 20 min, 9 nm red shift in surface plasmon resonance peak (SPR), along with increased broadening towards longer wavelength, was observed in the AuNPs–S-ovalbumin sample. Further increase in the time of irradiation showed shift in AuNPs–S-ovalbumin SPR towards lower wavelength. On laser irradiation (532 nm, 15 mJ) for 20 min, no significant change was observed in the line shape of the plasmon absorption band of the AgNPs–S-ovalbumin conjugate. FTIR spectra revealed that S-ovalbumin peptide backbone and secondary structure remain unchanged on laser irradiation during in situ conjugation process. Thus, integrity of S-ovalbumin does not get affected, and no degradation of S-ovalbumin takes place on laser-induced in situ conjugation. Raman results confirm that both Au and Ag NPs interact with S-ovalbumin via thiol-bearing cysteine residues of the disulfide bond.

  9. In-situ observation of Cu-Pt core-shell nanoparticles in the atomic scale by XAFS

    International Nuclear Information System (INIS)

    Zheng, Xusheng; Liu, Shoujie; Chen, Xing; Cheng, Jie; Ye, Qing; Pan, Zhiyun; Chu, Wangsheng; Wu, Ziyu; Marcelli, Augosto

    2013-01-01

    Bimetallic nanoparticles play an important role in potential industrial applications, such as catalysis, optoelectronics, information storage and biological labeling. Herein, homogeneous Cu-Pt core-shell nanoparticles with the averaged size of 8 nm have been synthesized by chemical methods. Cu atoms diffusion process, which motivated by heating, was observed in-situ by using temperature-dependent x-ray absorption fine-structure (XAFS) spectroscopy. Results show that Cu diffuse gradually from Cu core to Pt shell in these nanoparticles with increasing temperature. We also found the surface ligand (O) bonded Pt at the room temperature and were removed gradually by heating the sample. The analysis of the diffusion process in bimetallic nanoparticles will provide important guideline for their designing and tuning.

  10. In situ Electrochemical Small-Angle Neutron Scattering (eSANS) for Quantitative Structure and Redox Properties of Nanoparticles.

    Science.gov (United States)

    Prabhu, Vivek M; Reipa, Vytas

    2012-03-01

    The rapid growth in nanomaterial applications have revealed limitations in available physicochemical characterization methods. An in situ electrochemical small-angle neutron scattering (eSANS) methodology was devised that enables direct measurements of nanomaterial dispersion structure while undergoing reduction-oxidation (redox) reactions at the vitreous carbon electrode. Furthermore, these porous electrodes are amenable to contrast-variant neutron scattering strategies to measure nanoparticle structure and polymer conformation in multicomponent systems. The eSANS method was tested for feasibility by characterizing ZnO nanoparticles in 50 mmol/L NaCl deuterium oxide solution undergoing bulk electrolysis at negative potentials. Irreversible nanoparticle structural changes are observed during the potential cycle. The complete reduction of Zn(2+) to Zn(0) nanoparticles is unlikely, but a peak in the characteristic correlation length occurs during the redox bias with reduced average characteristic size.

  11. In Situ Production of Copper Oxide Nanoparticles in a Binary Molten Salt for Concentrated Solar Power Plant Applications

    Directory of Open Access Journals (Sweden)

    Mathieu Lasfargues

    2017-05-01

    Full Text Available Seeding nanoparticles in molten salts has been shown recently as a promising way to improve their thermo-physical properties. The prospect of such technology is of interest to both academic and industrial sectors in order to enhance the specific heat capacity of molten salt. The latter is used in concentrated solar power plants as both heat transfer fluid and sensible storage. This work explores the feasibility of producing and dispersing nanoparticles with a novel one pot synthesis method. Using such a method, CuO nanoparticles were produced in situ via the decomposition of copper sulphate pentahydrate in a KNO3-NaNO3 binary salt. Analyses of the results suggested preferential disposition of atoms around produced nanoparticles in the molten salt. Thermal characterization of the produced nano-salt suspension indicated the dependence of the specific heat enhancement on particle morphology and distribution within the salts.

  12. In Situ Production of Copper Oxide Nanoparticles in a Binary Molten Salt for Concentrated Solar Power Plant Applications.

    Science.gov (United States)

    Lasfargues, Mathieu; Stead, Graham; Amjad, Muhammad; Ding, Yulong; Wen, Dongsheng

    2017-05-19

    Seeding nanoparticles in molten salts has been shown recently as a promising way to improve their thermo-physical properties. The prospect of such technology is of interest to both academic and industrial sectors in order to enhance the specific heat capacity of molten salt. The latter is used in concentrated solar power plants as both heat transfer fluid and sensible storage. This work explores the feasibility of producing and dispersing nanoparticles with a novel one pot synthesis method. Using such a method, CuO nanoparticles were produced in situ via the decomposition of copper sulphate pentahydrate in a KNO₃-NaNO₃ binary salt. Analyses of the results suggested preferential disposition of atoms around produced nanoparticles in the molten salt. Thermal characterization of the produced nano-salt suspension indicated the dependence of the specific heat enhancement on particle morphology and distribution within the salts.

  13. Growth of block copolymer stabilized metal nanoparticles probed simultaneously by in situ XAS and UV-Vis spectroscopy.

    Science.gov (United States)

    Nayak, C; Bhattacharyya, D; Jha, S N; Sahoo, N K

    2016-01-01

    The growth of Au and Pt nanoparticles from their respective chloride precursors using block copolymer-based reducers has been studied by simultaneous in situ measurement of XAS and UV-Vis spectroscopy at the energy-dispersive EXAFS beamline (BL-08) at INDUS-2 SRS at RRCAT, Indore, India. While the XANES spectra of the precursor give real-time information on the reduction process, the EXAFS spectra reveal the structure of the clusters formed at the intermediate stages of growth. The growth kinetics of both types of nanoparticles are found to be almost similar and are found to follow three stages, though the first stage of nucleation takes place earlier in the case of Au than in the case of Pt nanoparticles due to the difference in the reduction potential of the respective precursors. The first two stages of the growth of Au and Pt nanoparticles as obtained by in situ XAS measurements could be corroborated by simultaneous in situ measurement of UV-Vis spectroscopy also.

  14. In situ atomic-scale observation of oxygen-driven core-shell formation in Pt3Co nanoparticles.

    Science.gov (United States)

    Dai, Sheng; You, Yuan; Zhang, Shuyi; Cai, Wei; Xu, Mingjie; Xie, Lin; Wu, Ruqian; Graham, George W; Pan, Xiaoqing

    2017-08-07

    The catalytic performance of core-shell platinum alloy nanoparticles is typically superior to that of pure platinum nanoparticles for the oxygen reduction reaction in fuel cell cathodes. Thorough understanding of core-shell formation is critical for atomic-scale design and control of the platinum shell, which is known to be the structural feature responsible for the enhancement. Here we reveal details of a counter-intuitive core-shell formation process in platinum-cobalt nanoparticles at elevated temperature under oxygen at atmospheric pressure, by using advanced in situ electron microscopy. Initial segregation of a thin platinum, rather than cobalt oxide, surface layer occurs concurrently with ordering of the intermetallic core, followed by the layer-by-layer growth of a platinum shell via Ostwald ripening during the oxygen annealing treatment. Calculations based on density functional theory demonstrate that this process follows an energetically favourable path. These findings are expected to be useful for the future design of structured platinum alloy nanocatalysts.Core-shell platinum alloy nanoparticles are promising catalysts for oxygen reduction, however a deeper understanding of core-shell formation is still required. Here the authors report oxygen-driven formation of core-shell Pt 3 Co nanoparticles, seen at the atomic scale with in situ electron microscopy at ambient pressure.

  15. In Situ Spectroscopy and Mechanistic Insights into CO Oxidation on Transition-Metal-Substituted Ceria Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Joseph S.; Stoerzinger, Kelsey A.; Hong, Wesley T.; Risch, Marcel; Giordano, Livia [Dipartimento; Mansour, Azzam N. [Naval; Shao-Horn, Yang

    2017-09-12

    Herein we investigate the reaction intermediates formed during CO oxidation on copper-substituted ceria nanoparticles (Cu0.1Ce0.9O2–x) by means of in situ spectroscopic techniques and identify an activity descriptor that rationalizes a trend with other metal substitutes (M0.1Ce0.9O2–x, M = Mn, Fe, Co, Ni). In situ X-ray absorption spectroscopy (XAS) performed under catalytic conditions demonstrates that O2– transfer occurs at dispersed copper centers, which are redox active during catalysis. In situ XAS reveals a dramatic reduction at the copper centers that is fully reversible under catalytic conditions, which rationalizes the high catalytic activity of Cu0.1Ce0.9O2–x. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) show that CO can be oxidized to CO32– in the absence of O2. We find that CO32– desorbs as CO2 only under oxygen-rich conditions when the oxygen vacancy is filled by the dissociative adsorption of O2. These data, along with kinetic analyses, lend support to a mechanism in which the breaking of copper–oxygen bonds is rate-determining under oxygen-rich conditions, while refilling the resulting oxygen vacancy is rate-determining under oxygen-lean conditions. On the basis of these observations and density functional calculations, we introduce the computed oxygen vacancy formation energy (Evac) as an activity descriptor for substituted ceria materials and demonstrate that Evac successfully rationalizes the trend in the activities of M0.1Ce0.9O2–x catalysts that spans three orders of magnitude. The applicability of Evac as a useful design descriptor is demonstrated by the catalytic performance of the ternary oxide Cu0.1La0.1Ce0.8O2–x, which has an apparent activation energy rivaling those of state-of-the-art Au/TiO2 materials. Thus, we suggest that cost-effective catalysts for CO oxidation can be rationally designed by judicious choice of substituting

  16. High impact of in situ dextran coating on biocompatibility, stability and magnetic properties of iron oxide nanoparticles.

    Science.gov (United States)

    Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

    2017-06-01

    Biocompatible ferrofluids based on dextran coated iron oxide nanoparticles were fabricated by conventional co-precipitation method. The experimental results show that the presence of dextran in reaction medium not only causes to the appearance of superparamagnetic behavior but also results in significant suppression in saturation magnetization of dextran coated samples. These results can be attributed to size reduction originated from the role of dextran as a surfactant. Moreover, weight ratio of dextran to magnetic nanoparticles has a remarkable influence on size and magnetic properties of nanoparticles, so that the sample prepared with a higher weight ratio of dextran to nanoparticles has the smaller size and saturation magnetization compare with the other samples. In addition, the ferrofluids containing such nanoparticles have an excellent stability at physiological pH for several months. Furthermore, the biocompatibility studies reveal that surface modification of nanoparticles by dextran dramatically decreases the cytotoxicity of bare nanoparticles and consequently improves their potential application for diagnostic and therapeutic purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Nanoparticles of the superconductor MgB2: structural characterization and in situ study of synthesis kinetics

    International Nuclear Information System (INIS)

    Cui Chunxiang; Liu Debao; Shen Yutian; Sun Jinbin; Meng Fanbin; Wang Ru; Liu Shuangjin; Greer, A.L.; Chen, S.K.; Glowacki, B.A.

    2004-01-01

    Single-crystal MgB 2 nanoparticles, with diameters in the range 20-100 nm, have been synthesized in situ in the sample chamber of an X-ray diffractometer. The reaction kinetics are analyzed and related to the atomic-level structure of the particles as observed by high-resolution electron microscopy. Synthesis conditions may have a significant influence on microstructure and superconducting properties

  18. Influence of Structural Defects on Biomineralized ZnS Nanoparticle Dissolution: An in-Situ Electron Microscopy Study.

    Science.gov (United States)

    Eskelsen, Jeremy R; Xu, Jie; Chiu, Michelle; Moon, Ji-Won; Wilkins, Branford; Graham, David E; Gu, Baohua; Pierce, Eric M

    2018-02-06

    The dissolution of metal sulfides, such as ZnS, is an important biogeochemical process affecting fate and transport of trace metals in the environment. However, current studies of in situ dissolution of metal sulfides and the effects of structural defects on dissolution are lacking. Here we have examined the dissolution behavior of ZnS nanoparticles synthesized via several abiotic and biological pathways. Specifically, we have examined biogenic ZnS nanoparticles produced by an anaerobic, metal-reducing bacterium Thermoanaerobacter sp. X513 in a Zn-amended, thiosulfate-containing growth medium in the presence or absence of silver (Ag), and abiogenic ZnS nanoparticles were produced by mixing an aqueous Zn solution with either H 2 S-rich gas or Na 2 S solution. The size distribution, crystal structure, aggregation behavior, and internal defects of the synthesized ZnS nanoparticles were examined using high-resolution transmission electron microscopy (TEM) coupled with X-ray energy dispersive spectroscopy. The characterization results show that both the biogenic and abiogenic samples were dominantly composed of sphalerite. In the absence of Ag, the biogenic ZnS nanoparticles were significantly larger (i.e., ∼10 nm) than the abiogenic ones (i.e., ∼3-5 nm) and contained structural defects (e.g., twins and stacking faults). The presence of trace Ag showed a restraining effect on the particle size of the biogenic ZnS, resulting in quantum-dot-sized nanoparticles (i.e., ∼3 nm). In situ dissolution experiments for the synthesized ZnS were conducted with a liquid-cell TEM (LCTEM), and the primary factors (i.e., the presence or absence structural defects) were evaluated for their effects on the dissolution behavior using the biogenic and abiogenic ZnS nanoparticle samples with the largest average particle size. Analysis of the dissolution results (i.e., change in particle radius with time) using the Kelvin equation shows that the defect-bearing biogenic ZnS nanoparticles

  19. In situ TEM observation of the Boudouard reaction: Multi-layered graphene formation from CO on cobalt nanoparticles at atmospheric pressure

    NARCIS (Netherlands)

    Bremmer, G.M.; Zacharaki, E.; Sjåstad, A.O.; Navarro, V.; Frenken, J.W.M.; Kooyman, P.J.

    2017-01-01

    Using a MEMS nanoreactor in combination with a specially designed in situ Transmission Electron Microscope (TEM) holder and gas supply system, we imaged the formation of multiple layers of graphene encapsulating a cobalt nanoparticle, at 1 bar CO:N2 (1:1) and 500 °C. The cobalt nanoparticle was

  20. Carbide Nanoparticles Encapsulated in the Caves of Carbon Nanotubes by an In Situ Reduction-Carbonization Route

    Directory of Open Access Journals (Sweden)

    Chunli Guo

    2011-01-01

    Full Text Available Carbides (TiC, WC, and NbC nanoparticles fully encapsulated in the caves of carbon nanotubes (CNTs were synthesized via an in situ reduction-carbonization route at 600∘C in an autoclave. The structural features and morphologies of as-obtained products were investigated using by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy (HRTEM. HRTEM studies showed that the average diameter of CNTs encapsulated with carbide nanoparticles are in the range of 15–40 nm. The reaction temperature, the reaction time, and the metal catalyst are found to play crucial roles to the product morphology. The growth mechanism of carbide nanoparticles encapsulated in CNTs was discussed in detail.

  1. TOPICAL REVIEW: Synthesis and applications of magnetic nanoparticles for biorecognition and point of care medical diagnostics

    Science.gov (United States)

    Sandhu, Adarsh; Handa, Hiroshi; Abe, Masanori

    2010-11-01

    Functionalized magnetic nanoparticles are important components in biorecognition and medical diagnostics. Here, we present a review of our contribution to this interdisciplinary research field. We start by describing a simple one-step process for the synthesis of highly uniform ferrite nanoparticles (d = 20-200 nm) and their functionalization with amino acids via carboxyl groups. For real-world applications, we used admicellar polymerization to produce 200 nm diameter 'FG beads', consisting of several 40 nm diameter ferrite nanoparticles encapsulated in a co-polymer of styrene and glycidyl methacrylate for high throughput molecular screening. The highly dispersive FG beads were functionalized with an ethylene glycol diglycidyl ether spacer and used for affinity purification of methotrexate—an anti-cancer agent. We synthesized sub-100 nm diameter magnetic nanocapsules by exploiting the self-assembly of viral capsid protein pentamers, where single 8, 20, and 27 nm nanoparticles were encapsulated with VP1 pentamers for applications including MRI contrast agents. The FG beads are now commercially available for use in fully automated bio-screening systems. We also incorporated europium complexes inside a polymer matrix to produce 140 nm diameter fluorescent-ferrite beads (FF beads), which emit at 618 nm. These FF beads were used for immunofluorescent staining for diagnosis of cancer metastases to lymph nodes during cancer resection surgery by labeling tumor cell epidermal growth factor receptor (EGFRs), and for the detection of brain natriuretic peptide (BNP)—a hormone secreted in excess amounts by the heart when stressed—to a level of 2.0 pg ml - 1. We also describe our work on Hall biosensors made using InSb and GaAs/InGaAs/AlGaAs 2DEG heterostructures integrated with gold current strips to reduce measurement times. Our approach for the detection of sub-200 nm magnetic bead is also described: we exploit the magnetically induced capture of micrometer sized 'probe

  2. Persistent luminescent nanoparticles for super-long time in vivo and in situ imaging with repeatable excitation

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Meng; Li, Zhan-Jun; Liu, Chun-Lin; Fu, Hai-Xia; Shen, Jiang-Shan; Zhang, Hong-Wu, E-mail: hwzhang@iue.ac.cn

    2014-01-15

    In order to realize super-long time (more than 3 days) in vivo imaging, SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+} (SAO) nanoparticles were employed as probes with in situ repeatable excitation capability. In our experiments, strontium aluminate nanoparticles were prepared. After surface modified with pyrophosphoric acid (PPA), grafted by PEG-5000-OCH{sub 3} and irradiated with 365 nm UV light for 10 min, the afterglow signal can be observed in real time for more than 30 min in live mouse after intravenous injection. In order to monitor for a super-long time, the mouse was re-illuminated for 10 min by a white-light LED lamp and then the imaging signals were recovered and also persisted for 30 min again. The super-long time in vivo imaging was achieved by employing these repeatedly excited luminescent nanoprobes. -- Highlights: • The water-resistance and dispersity abilities of strontium aluminate nanoparticles were achieved by surface modification with pyrophosphoric acid and polyethylene glycol (PEG). • The synthesized nanoparticles were successfully employed in in vivo imaging. • A super-long time in vivo imaging was realized by the in situ re-excitation via a LED lamp.

  3. In-situ suspended aggregate microextraction of gold nanoparticles from water samples and determination by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Choleva, Tatiana G; Kappi, Foteini A; Tsogas, George Z; Vlessidis, Athanasios G; Giokas, Dimosthenis L

    2016-05-01

    This work describes a new method for the extraction and determination of gold nanoparticles in environmental samples by means of in-situ suspended aggregate microextraction and electrothermal atomic absorption spectrometry. The method relies on the in-situ formation of a supramolecular aggregate phase through ion-association between a cationic surfactant and a benzene sulfonic acid derivative. Gold nanoparticles are physically entrapped into the aggregate phase which is separated from the bulk aqueous solution by vacuum filtration on the surface of a cellulose filter in the form of a thin film. The film is removed from the filter surface and is dissociated into an acidified methanolic solution which is used for analysis. Under the optimized experimental conditions, gold nanoparticles can be efficiently extracted from water samples with recovery rates between 81.0-93.3%, precision 5.4-12.0% and detection limits as low as 75femtomolL(-1) using only 20mL of sample volume. The satisfactory analytical features of the method along with the simplicity indicate the efficiency of this new approach to adequately collect and extract gold nanoparticle species from water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Cellulose aerogels functionalized with polypyrrole and silver nanoparticles: In-situ synthesis, characterization and antibacterial activity.

    Science.gov (United States)

    Wan, Caichao; Li, Jian

    2016-08-01

    Green porous and lightweight cellulose aerogels have been considered as promising candidates to substitute some petrochemical host materials to support various nanomaterials. In this work, waste wheat straw was collected as feedstock to fabricate cellulose hydrogels, and a green inexpensive NaOH/polyethylene glycol solution was used as cellulose solvent. Prior to freeze-drying treatment, the cellulose hydrogels were integrated with polypyrrole and silver nanoparticles by easily-operated in-situ oxidative polymerization of pyrrole using silver ions as oxidizing agent. The tri-component hybrid aerogels were characterized by scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and X-ray diffraction. Moreover, the antibacterial activity of the hybrid aerogels against Escherichia coli (Gram-negative), Staphylococcus aureus (Gram-positive) and Listeria monocytogenes (intracellular bacteria) was qualitatively and quantitatively investigated by parallel streak method and determination of minimal inhibitory concentration, respectively. This work provides an example of combining cellulose aerogels with nanomaterials, and helps to develop novel forms of cellulose-based functional materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. In Situ Assembly of Nanoparticles into Hierarchical Beta Zeolite with Tailored Simple Organic Molecule.

    Science.gov (United States)

    Zhang, Kai; Liu, Zewei; Yan, Xin; Hao, Xuelong; Wang, Min; Li, Chao; Xi, Hongxia

    2017-12-19

    A hierarchically structured beta zeolite with intercrystalline mesopores was successfully synthesized via in situ assembly of nanoparticles by employing a simple organic molecule N 2 -p-N 2 , tailored from polyquaternium surfactant, with no hydrophobic long chain. The generated samples were studied by using powder X-ray diffraction (XRD) and nitrogen adsorption/desorption isotherms. Computer simulation, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) technologies were also used. The characterized results show that the tailored template molecule N 2 -p-N 2 without hydrophobic long-chain tail still can direct the zeolite crystallization, while the hydrophobic long-chain tail is not necessary during the mesoporous Beta zeolite formation. The catalytic performances of the sample were studied using alkylation of benzene with propene reaction to evaluate the relationship between the structure and property. The results apparently suggested an overall improved resistance against deactivation as compared to conventional beta zeolite in reactions. Furthermore, this tailored simple organic molecule strategy from dual-functional surfactant for making mesoporous zeolite would offer a new method of synthesizing other hierarchically structured zeolites.

  6. In situ optical monitoring of RDX nanoparticles formation during rapid expansion of supercritical CO2 solutions.

    Science.gov (United States)

    Matsunaga, Takuya; Chernyshev, Andrei V; Chesnokov, Evgeni N; Krasnoperov, Lev N

    2007-10-14

    Nanoparticles of RDX (cyclotrimethylenetrinitramine) generated by RESS (rapid expansion of supercritical solutions) using supercritical CO2 were characterized in situ by a pulsed laser light scattering imaging technique using a gated ICCD (intensified CCD) camera. The absolute sensitivity calibration was performed using Rayleigh light scattering from air as well as light scattering from standard polystyrene spheres. The size distribution functions of the particles formed in the RESS jet were determined using the calibrated sensitivity. The diameter of RDX particles formed at the pre-expansion pressure of 180 bar was 73 nm at the maximum of the size distribution function. Assuming that the particles near the nozzle consisted mainly of CO2 and the size distribution was log-normal, the diameter of the particles near the nozzle (7.5 mm from the nozzle) at the distribution maximum was 3.3 microm at the pre-expansion pressure of 180 bar. The number densities of the particles in the RESS jet were determined by counting individual particles in the light scattering images. Based on the measured particle size distributions and the number density of particles along the RESS jet, the mechanism of particle formation in RESS is discussed. The homogeneous nucleation mechanism is rejected as it fails to explain the large particle size experimentally observed. Instead, a modified "spray-drying" mechanism is suggested.

  7. A Software App for Radiotherapy with In-situ Dose-painting using high Z nanoparticles.

    Science.gov (United States)

    Jermoumi, M; Yucel, A; Hao, Y; Cifter, G; Sajo, E; Ngwa, W

    2015-06-01

    The purpose of this work is to develop an user friendly and free-to-download application software that can be employed for modeling Radiotherapy with In-situ Dose-painting (RAID) using high-Z nanoparticles (HZNPs). The RAID APP is software program written in Matlab (Mathworks, Natick, MA, USA) based on deterministic code developed to simulate the space-time intra-tumor HZNPs biodistribution within the tumor, and the corresponding dose enhancement in response to low dose rate (LDR) brachytherapy of I-125, Pd-102, Cs-131 and kilovoltage x-rays such as 50 keV and 100 keV. Through the GUI of RAID APP, the user will be directed to different features to compute various parameters related to the dose enhancement and the biodistribution of NPs within high risk tumor sub-volumes. The software was developed as tool for research purposes with potential for subsequent development to guide dose-painting treatment planning using radiosensitizers such as gold (Au) and platinum (Pt).

  8. Zero-valent iron nanoparticles in treatment of acid mine water from in situ uranium leaching.

    Science.gov (United States)

    Klimkova, Stepanka; Cernik, Miroslav; Lacinova, Lenka; Filip, Jan; Jancik, Dalibor; Zboril, Radek

    2011-02-01

    Acid mine water from in situ chemical leaching of uranium (Straz pod Ralskem, Czech Republic) was treated in laboratory scale experiments by zero-valent iron nanoparticles (nZVI). For the first time, nZVI were applied for the treatment of the real acid water system containing the miscellaneous mixture of pollutants, where the various removal mechanisms occur simultaneously. Toxicity of the treated saline acid water is caused by major contaminants represented by aluminum and sulphates in a high concentration, as well as by microcontaminants like As, Be, Cd, Cr, Cu, Ni, U, V, and Zn. Laboratory batch experiments proved a significant decrease in concentrations of all the monitored pollutants due to an increase in pH and a decrease in oxidation-reduction potential related to an application of nZVI. The assumed mechanisms of contaminants removal include precipitation of cations in a lower oxidation state, precipitation caused by a simple pH increase and co-precipitation with the formed iron oxyhydroxides. The possibility to control the reaction kinetics through the nature of the surface stabilizing shell (polymer vs. FeO nanolayer) is discussed as an important practical aspect. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. In Situ Synthesis of Catalytic Active Au Nanoparticles onto Gibbsite-Polydopamine Core-Shell Nanoplates.

    Science.gov (United States)

    Cao, Jie; Mei, Shilin; Jia, He; Ott, Andreas; Ballauff, Matthias; Lu, Yan

    2015-09-01

    We report a facile method to synthesize anisotropic platelike gibbsite-polymer core-shell particles. Dopamine is self-polymerized on the surface of gibbsite nanoplates and forms a homogeneous layer on it. Transmission electron microscopy characterization of the resulting latexes demonstrates the formation of well-defined platelike core-shell particles. Reaction time and ultrasonification are found to be important factors to control the thickness of the polymer shell and avoid aggregation. Good control over the platelike morphology and 100% encapsulation efficiency have been achieved via this novel route. The resulting well-defined gibbsite-polydamine (G-PDA) core-shell nanoplates show excellent colloidal stability and can form opal-like columnar crystal with iridescent Bragg reflection after modest centrifugation. In addition, G-PDA core-shell nanoplates can serve both as reductant and stabilizer for the generation of Au nanoparticles (NPs) in situ. Au NPs with tunable size have been formed on the G-PDA particle surface, which show efficient catalytic activity for the reduction of 4-nitrophenol and Rhodamine B (RhB) in the presence of borohydride. Such nanocatalysts can be easily deposited on silicon substrate by spin-coating due to the large contact area of platelike G-PDA particles and the strong adhesive behavior of the PDA layer. The substrate-deposited nanocatalyst can be easily recycled which show excellent reusability for the reduction of RhB.

  10. In situ immobilization of tin dioxide nanoparticles by nanoporous polymers scaffold toward monolithic humidity sensing devices.

    Science.gov (United States)

    Wei, Shu; Han, Dong-Dong; Guo, Li; He, Yinyan; Ding, Hong; Zhang, Yong-Lai; Xiao, Feng-Shou

    2014-10-01

    Reported here is in situ immobilization of tin dioxide (SnO2) nanoparticles (NPs) within nanoporous polymer scaffolds for the development of monolithic humidity sensing devices. Through solvothermal polymerization of divinylbenzene (DVB) monomers in the interspaces of SnO2 fine powders, SnO2 NPs could be homogeneously immobilized in polymer matrices, forming a novel composite material. Immobilization of SnO2 NPs in nanoporous polymer matrices not only simplifies the fabrication process of NPs-based sensing devices, but also improves their adsorptive properties. The resultant nanoporous polymer/SnO2 NPs composites with adjustable SnO2 contents possess high BET surface areas, large pore sizes and pore volumes, thus they exhibit high adsorptive capacities for H2O vapor. As a general approach to NPs/nanoporous polymer composites, this work may open up a new way to nanomaterial-based sensing devices that features enhanced adsorptive property. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. An in situ accelerator-based diagnostic for plasma-material interactions science on magnetic fusion devices.

    Science.gov (United States)

    Hartwig, Zachary S; Barnard, Harold S; Lanza, Richard C; Sorbom, Brandon N; Stahle, Peter W; Whyte, Dennis G

    2013-12-01

    This paper presents a novel particle accelerator-based diagnostic that nondestructively measures the evolution of material surface compositions inside magnetic fusion devices. The diagnostic's purpose is to contribute to an integrated understanding of plasma-material interactions in magnetic fusion, which is severely hindered by a dearth of in situ material surface diagnosis. The diagnostic aims to remotely generate isotopic concentration maps on a plasma shot-to-shot timescale that cover a large fraction of the plasma-facing surface inside of a magnetic fusion device without the need for vacuum breaks or physical access to the material surfaces. Our instrument uses a compact (~1 m), high-current (~1 milliamp) radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak at MIT. We control the tokamak magnetic fields--in between plasma shots--to steer the deuterons to material surfaces where the deuterons cause high-Q nuclear reactions with low-Z isotopes ~5 μm into the material. The induced neutrons and gamma rays are measured with scintillation detectors; energy spectra analysis provides quantitative reconstruction of surface compositions. An overview of the diagnostic technique, known as accelerator-based in situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod tokamak is given. Experimental validation is shown to demonstrate that an optimized deuteron beam is injected into the tokamak, that low-Z isotopes such as deuterium and boron can be quantified on the material surfaces, and that magnetic steering provides access to different measurement locations. The first AIMS analysis, which measures the relative change in deuterium at a single surface location at the end of the Alcator C-Mod FY2012 plasma campaign, is also presented.

  12. Upgraded PMI diagnostic capabilities using Accelerator-based In-situ Materials Surveillance (AIMS) on Alcator C-Mod

    Science.gov (United States)

    Kesler, Leigh; Barnard, Harold; Hartwig, Zachary; Sorbom, Brandon; Lanza, Richard; Terry, David; Vieira, Rui; Whyte, Dennis

    2014-10-01

    The AIMS diagnostic was developed to rapidly and non-invasively characterize in-situ plasma material interactions (PMI) in a tokamak. Recent improvements are described which significantly expand this measurement capability on Alcator C-Mod. The detection time at each wall location is reduced from about 10 min to 30 s, via improved hardware and detection geometry. Detectors are in an augmented re-entrant tube to maximize the solid angle between detectors and diagnostic locations. Spatial range is expanded by using beam dynamics simulation to design upgraded B-field power supplies to provide maximal poloidal access, including a ~20° toroidal range in the divertor. Measurement accuracy is improved with angular and energy resolved cross section measurements obtained using a separate 0.9 MeV deuteron ion accelerator. Future improvements include the installation of recessed scintillator tiles as beam targets for calibration of the diagnostic. Additionally, implanted depth marker tiles will enable AIMS to observe the in-situ erosion and deposition of high-Z plasma-facing materials. This work is supported by U.S. DOE Grant No. DE-FG02-94ER54235 and Cooperative Agreement No. DE-FC02-99ER54512.

  13. Synthesis and characterization of gold nanoparticles as diagnostic and therapeutic tool

    International Nuclear Information System (INIS)

    Costa, Pryscila Rodrigues da

    2012-01-01

    Nanomedicine covers the use of nanoparticles to the targeted site of action as platforms for building imaging and therapeutic agents against cancer and other human diseases. In particular, gold nanoparticles (AuNp's) have proven to be efficient for the diagnosis and therapy. Interest in the development of AuNp's is due to their extraordinary physical and chemical properties resulting from the effect of its size in the nanoscale, to have an area of easy modification and the radioactive γ and β emitter ( 198 Au; Eγ = 0,411 MeV, β max = 0,96 MeV; T 1/2 = 2,69 days), having the advantage of being able to be applied as a diagnostic tool for molecular photon emission tomography (SPECT) using only a small amount of radioactive gold . In this study were synthesized AuNp's, whose surface is functionalized with a biocompatible polymer (modified polyethylene glycol) and folic acid in order to render them stealth and specific tumors that over express the folate receptors. The techniques of Dynamic Light Scattering (DLS), zeta potential (ζ), transmission electron microscopy (TEM) and UV-Visible absorption spectroscopy were employed to characterization of the size and geometry of the nanoparticles, in addition to confirming its binding to thiol -PEG and PEG-thiol Folate. The results of UV-Visible and TEM showed the formation of dispersed AuNp's ranging in size from 8-12 nm with a strong absorption around 520 nm, relating to a maximum of surface plasmon resonance. DLS results showed a hydrodynamic diameter of 10 and 14 nm. The (pH ∼ 5.0 to 6.0) ranged ζ potential values of the dispersions prepared between -16.2 and -42.1 mV, indicating stable colloidal suspensions. To determine the real concentration of gold in the samples, it was used neutron activation in the nuclear reactor TRIGA MARK I IPR-R1 CDTN / CNEN of Belo Horizonte. Biocompatibility studies in vitro and in vivo of the samples were carried out showing that they have low toxicity in the models used. We evaluated

  14. Ultrasonic-assisted in situ synthesis and characterization of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jie [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Mao Jian, E-mail: maojianemail@163.com [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Wen Xiaogang; Tu Mingjing [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China)

    2011-09-15

    Highlights: > Fe{sup 3+} as the only Fe source for preparing Fe{sub 3}O{sub 4} nanoparticles through in situ cover and sonication method. > Surface modification enables the reduction of the grain size of Fe{sub 3}O{sub 4}. > Increasing temperature reduces grain size of Fe{sub 3}O{sub 4} until it exceeds 80 deg. C. > Increasing pH values reduces grain size of Fe{sub 3}O{sub 4} until it exceeds 11. > Saturation magnetizations depend on the grain size of Fe{sub 3}O{sub 4} nanoparticles. - Abstract: Superparamagnetic Fe{sub 3}O{sub 4} nanoparticles were synthesized via a modified coprecipitation method, and were characterized with X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Zeta potential and FT-IR, respectively. The influences of different kinds of surfactants (sodium dodecyl benzene sulfonate, polyethyleneglycol, oleic acid and dextran), temperatures and pH values on the grain size and properties were also investigated. In this method, Fe{sup 3+} was used as the only Fe source and partially reduced to Fe{sup 2+} by the reducing agent with precise content. The following reaction between Fe{sup 3+}, Fe{sup 2+} and hydroxide radical brought pure Fe{sub 3}O{sub 4} nanoparticles. The tiny fresh nanoparticles were coated in situ with surfactant under the action of sonication. Comparing with uncoated sample, the mean grain size and saturation magnetization of coated Fe{sub 3}O{sub 4} nanoparticles decrease from 18.4 nm to 5.9-9.0 nm, and from 63.89 emu g{sup -1} to 52-58 emu g{sup -1} respectively. When oleic was used as the surfactant, the mean grain size of Fe{sub 3}O{sub 4} nanoparticles firstly decreases with the increase of reaction temperature, but when the temperature is exceed to 80 deg. C, the continuous increase of temperature resulted in larger nanoparticles. the grain size decreases gradually with the increasing of pH values, and it remains unchanged when the PH value is up to 11. The saturation magnetization of as-prepared Fe{sub 3}O{sub 4

  15. Ultrasound irradiation based in-situ synthesis of star-like Tragacanth gum/zinc oxide nanoparticles on cotton fabric.

    Science.gov (United States)

    Ghayempour, Soraya; Montazer, Majid

    2017-01-01

    Application of natural biopolymers for green and safe synthesis of zinc oxide nanoparticles on the textiles is a novel and interesting approach. The present study offers the use of natural biopolymer, Tragacanth gum, as the reducing, stabilizing and binding agent for in-situ synthesis of zinc oxide nanoparticles on the cotton fabric. Ultrasonic irradiation leads to clean and easy synthesis of zinc oxide nanoparticles in short-time at low-temperature. FESEM/EDX, XRD, FT-IR spectroscopy, DSC, photocatalytic activities and antimicrobial assay are used to characterize Tragacanth gum/zinc oxide nanoparticles coated cotton fabric. The analysis confirmed synthesis of star-like zinc oxide nanoparticles with hexagonal wurtzite structure on the cotton fabric with the average particle size of 62nm. The finished cotton fabric showed a good photocatalytic activity on degradation of methylene blue and 100% antimicrobial properties with inhibition zone of 3.3±0.1, 3.1±0.1 and 3.0±0.1mm against Staphylococcus aureus, Escherichia coli and Candida albicans. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Investigating the use of in situ liquid cell scanning transmission electron microscopy to explore DNA-mediated gold nanoparticle growth

    Science.gov (United States)

    Nguy, Amanda

    Engineering nanoparticles with desired shape-dependent properties is the key to many applications in nanotechnology. Although many synthetic procedures exist to produce anisotropic gold nanoparticles, the dynamics of growth are typically unknown or hypothetical. In the case of seed-mediated growth in the presence of DNA into anisotropic nanoparticles, it is not known exactly how DNA directs growth into specific morphologies. A series of preliminary experiments were carried out to contribute to the investigation of the possible mechanism of DNA-mediated growth of gold nanoprisms into gold nanostars using liquid cell scanning transmission electron microscopy (STEM). Imaging in the liquid phase was achieved through the use of a liquid cell platform and liquid cell holder that allow the sample to be contained within a “chip sandwich” between two electron transparent windows. Ex situ growth experiments were performed using Au-T30 NPrisms (30-base thymine oligonucleotide-coated gold nanoprisms) that are expected to grow into gold nanostars. Growth to form these nanostars were imaged using TEM (transmission electron microscopy) and liquid cell STEM (scanning transmission electron microscopy). An attempt to perform in situ growth experiments with the same Au-T30 nanoprisms revealed challenges in obtaining desired morphology results due to the environmental differences within the liquid cell compared to the ex situ environment. Different parameters in the experimental method were explored including fluid line set up, simultaneous and alternating reagent addition, and the effect of different liquid cell volumes to ensure adequate flow of reagents into the liquid cell. Lastly, the binding affinities were compared for T30 and A30 DNA incubated with gold nanoparticles using zeta potential measurements, absorption spectroscopy, and isothermal titration calorimetry (ITC). It was previously reported thymine bases have a lower binding affinity to gold surfaces than

  17. Nanoscale sensor design via in situ labeling of gold nanoparticles onto protein scaffolds.

    Science.gov (United States)

    Afrasiabi, Zahra; Shukla, Ravi; Chanda, Nripen; Bhaskaran, Sharanya; Upendran, Anandhi; Zambre, Ajit; Katti, Kattesh V; Kannan, Raghuraman

    2010-02-01

    A one-step method for synthesis of bioconjugated gold nanoparticles is reported. A non-toxic and biocompatible phosphorus based reducing agent was used for reduction of gold (III) and formation of nanoparticles. Physicochemical properties of protein-A stabilized gold nanoparticls were investigated. Result of immunoassay experiments confirmed the potential of the synthesized anti-protein-A conjugated gold nanoparticles for use as a simple and inexpensive test for quantitative screening of protein-A samples.

  18. In situ anomalous small-angle X-ray scattering studies of platinum nanoparticle fuel cell electrocatalyst degradation.

    Science.gov (United States)

    Gilbert, James A; Kariuki, Nancy N; Subbaraman, Ram; Kropf, A Jeremy; Smith, Matt C; Holby, Edward F; Morgan, Dane; Myers, Deborah J

    2012-09-12

    Polymer electrolyte fuel cells (PEFCs) are a promising high-efficiency energy conversion technology, but their cost-effective implementation, especially for automotive power, has been hindered by degradation of the electrochemically active surface area (ECA) of the Pt nanoparticle electrocatalysts. While numerous studies using ex situ post-mortem techniques have provided insight into the effect of operating conditions on ECA loss, the governing mechanisms and underlying processes are not fully understood. Toward the goal of elucidating the electrocatalyst degradation mechanisms, we have followed Pt nanoparticle growth during potential cycling of the electrocatalyst in an aqueous acidic environment using in situ anomalous small-angle X-ray scattering (ASAXS). ASAXS patterns were analyzed to obtain particle size distributions (PSDs) of the Pt nanoparticle electrocatalysts at periodic intervals during the potential cycling. Oxide coverages reached under the applied potential cycling protocols were both calculated and determined experimentally. Changes in the PSD, mean diameter, and geometric surface area identify the mechanism behind Pt nanoparticle coarsening in an aqueous environment. Over the first 80 potential cycles, the dominant Pt surface area loss mechanism when cycling to 1.0-1.1 V was found to be preferential dissolution or loss of the smallest particles with varying extents of reprecipitation of the dissolved species onto existing particles, resulting in particle growth, depending on potential profile. Correlation of ASAXS-determined particle growth with both calculated and voltammetrically determined oxide coverages demonstrates that the oxide coverage is playing a key role in the dissolution process and in the corresponding growth of the mean Pt nanoparticle size and loss of ECA. This understanding potentially reduces the complex changes in PSD and ECA resulting from various voltage profiles to a response dependent on oxide coverage.

  19. In situ growth of capping-free magnetic iron oxide nanoparticles on liquid-phase exfoliated graphene

    Science.gov (United States)

    Tsoufis, T.; Syrgiannis, Z.; Akhtar, N.; Prato, M.; Katsaros, F.; Sideratou, Z.; Kouloumpis, A.; Gournis, D.; Rudolf, P.

    2015-05-01

    We report a facile approach for the in situ synthesis of very small iron oxide nanoparticles on the surface of high-quality graphene sheets. Our synthetic strategy involved the direct, liquid-phase exfoliation of highly crystalline graphite (avoiding any oxidation treatment) and the subsequent chemical functionalization of the graphene sheets via the well-established 1,3-dipolar cycloaddition reaction. The resulting graphene derivatives were employed for the immobilization of the nanoparticle precursor (Fe cations) at the introduced organic groups by a modified wet-impregnation method, followed by interaction with acetic acid vapours. The final graphene-iron oxide hybrid material was achieved by heating (calcination) in an inert atmosphere. Characterization by X-ray diffraction, transmission electron and atomic force microscopy, Raman and X-ray photoelectron spectroscopy gave evidence for the formation of rather small (magnetite-rich nanoparticles which were evenly distributed on the surface of few-layer (nanoparticles, the hybrid material showed a superparamagnetic behaviour at room temperature.We report a facile approach for the in situ synthesis of very small iron oxide nanoparticles on the surface of high-quality graphene sheets. Our synthetic strategy involved the direct, liquid-phase exfoliation of highly crystalline graphite (avoiding any oxidation treatment) and the subsequent chemical functionalization of the graphene sheets via the well-established 1,3-dipolar cycloaddition reaction. The resulting graphene derivatives were employed for the immobilization of the nanoparticle precursor (Fe cations) at the introduced organic groups by a modified wet-impregnation method, followed by interaction with acetic acid vapours. The final graphene-iron oxide hybrid material was achieved by heating (calcination) in an inert atmosphere. Characterization by X-ray diffraction, transmission electron and atomic force microscopy, Raman and X-ray photoelectron spectroscopy

  20. In-situ formation of nanoparticles within a silicon-based matrix

    Science.gov (United States)

    Thoma, Steven G [Albuquerque, NM; Wilcoxon, Jess P [Albuquerque, NM; Abrams, Billie L [Albuquerque, NM

    2008-06-10

    A method for encapsulating nanoparticles with an encapsulating matrix that minimizes aggregation and maintains favorable properties of the nanoparticles. The matrix comprises silicon-based network-forming compounds such as ormosils and polysiloxanes. The nanoparticles are synthesized from precursors directly within the silicon-based matrix.

  1. The Effects of in Situ-Formed Silver Nanoparticles on the Electrical Properties of Epoxy Resin Filled with Silver Nanowires

    Directory of Open Access Journals (Sweden)

    Gwang-Seok Song

    2016-04-01

    Full Text Available A novel method for preparing epoxy/silver nanocomposites was developed via the in situ formation of silver nanoparticles (AgNPs within the epoxy resin matrix while using silver nanowires (AgNWs as a conductive filler. The silver–imidazole complex was synthesized from silver acetate (AgAc and 1-(2-cyanoethyl-2-ethyl-4-methylimidazole (imidazole. AgNPs were generated in situ during the curing of the epoxy resin through the thermal decomposition of the AgAc–imidazole complex, which was capable of reducing Ag+ to Ag by itself. The released imidazole acted as a catalyst to cure the epoxy. Additionally, after the curing process, the in situ-generated AgNPs were stabilized by the formed epoxy network. Therefore, by using the thermal decomposition method, uniformly dispersed AgNPs of approximately 100 nm were formed in situ in the epoxy matrix filled with AgNWs. It was observed that the nanocomposites containing in situ-formed AgNPs exhibited isotropic electrical properties in the epoxy resins in the presence of AgNWs.

  2. In situ UV–vis investigation of growth of gold nanoparticles prepared by solution plasma sputtering in NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Mizutani, Tsuyoshi, E-mail: mizutani.tsuyoshi@g.mbox.nagoya-u.ac.jp [Division of Quantum Science and Energy Engineering, Department of Materials, Physics and Energy Engineering, School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Ogawa, Satoshi [Division of Quantum Science and Energy Engineering, Department of Materials, Physics and Energy Engineering, School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Murai, Takaaki; Nameki, Hirofumi [Aichi Center for Industry and Science Technology, Onda, Kariya, Aichi 448-0013 (Japan); Yoshida, Tomoko; Yagi, Shinya [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-11-01

    Highlights: • In situ UV–vis measurement reveals diameters of gold nanoparticles and concentrations of gold. • Ostwald ripening of gold nanoparticles occurs in NaCl solution. • We estimate equilibrium diameters of gold nanoparticles in various concentrations of NaCl solution. - Abstract: Gold nanoparticles are prepared in various concentrations of NaCl solutions by solution plasma sputtering. The absorption spectra of these solutions during and after the plasma process are measured by in situ ultraviolet–visible (UV–vis) spectroscopy to estimate the particle diameters and concentrations of gold. The distributions of particle diameters are obtained by transmission electron microscope (TEM) observations. These experiments indicate the gold nanoparticles with about 2.2 nm are directly formed by plasma phase and the diameters are increasing over time. These increases of particle diameters are caused by Ostwald ripening of gold nanoparticles in NaCl solution. We estimate the equilibrium diameter at which the gold nanoparticles are not solved in NaCl solution using in situ UV–vis spectroscopy. These diameters are about 5, 7 and 10 nm in 3, 5 and 10 mM NaCl solution, respectively. We make it possible to control the diameter of gold nanoparticles prepared by solution plasma sputtering in NaCl solution.

  3. Influence of Structural Defects on Biomineralized ZnS Nanoparticle Dissolution: An In-Situ Electron Microscopy Study

    Energy Technology Data Exchange (ETDEWEB)

    Eskelsen, Jeremy R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Xu, Jie [Univ. of Texas, El Paso, TX (United States). Geological Sciences; Chiu, Michelle Y. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Moon, Ji-Won [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Wilkins, Branford O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Graham, David E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Gu, Baohua [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Pierce, Eric M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division

    2017-12-19

    The dissolution of metal sulfides, such as ZnS, plays an important role in the fate of metal contaminants in the environment. Here we have examined the dissolution behavior of ZnS nanoparticles synthesized via several abiotic and biological pathways. Specifically, the biogenic ZnS nanoparticles were produced by an anaerobic, metal-reducing bacterium Thermoanaerobacter sp. X513 in a Zn-amended, thiosulfate-containing growth medium, whereas the abiogenic ZnS nanoparticles were produced by mixing an aqueous Zn solution with either H2S-rich gas or Na2S solution. For biogenic synthesis, we prepared two types of samples, in the presence or absence of trace silver (Ag). The size distribution, crystal structure, aggregation behavior, and internal defects of the synthesized ZnS nanoparticles were primarily examined using high-resolution transmission electron microscopy coupled with X-ray energy dispersive spectroscopy. The characterization results show that both the biogenic and abiogenic samples were dominantly composed of sphalerite. In the absence of Ag, the biogenic ZnS nanoparticles were significantly larger (i.e., ~10 nm) than the abiogenic ones (i.e., ~3–5 nm) and contained structural defects (e.g., twins and stacking faults). The presence of trace Ag showed a restraining effect on the particle size of the biogenic ZnS, resulting in quantum-dot-sized nanoparticles (i.e., ~3 nm). In situ dissolution experiments for the synthesized ZnS were conducted with a liquid-cell coupled to a transmission electron microscope (LCTEM), and the primary factors (i.e., the presence or absence structural defects) were evaluated for their effects on the dissolution behavior using the biogenic and abiogenic ZnS nanoparticle samples with the largest average particle size. Analysis of the dissolution results (i.e., change in particle radius with time) using the Kelvin equation shows that the defect-bearing biogenic ZnS nanoparticles (γ = 0.799 J/m2) have

  4. An advanced electric propulsion diagnostic (AEPD) platform for in-situ characterization of electric propulsion thrusters and ion beam sources

    Science.gov (United States)

    Bundesmann, Carsten; Eichhorn, Christoph; Scholze, Frank; Spemann, Daniel; Neumann, Horst; Pagano, Damiano; Scaranzin, Simone; Scortecci, Fabrizio; Leiter, Hans J.; Gauter, Sven; Wiese, Ruben; Kersten, Holger; Holste, Kristof; Köhler, Peter; Klar, Peter J.; Mazouffre, Stéphane; Blott, Richard; Bulit, Alexandra; Dannenmayer, Käthe

    2016-10-01

    Experimental characterization is an essential task in development, qualification and optimization process of electric propulsion thrusters or ion beam sources for material processing, because it can verify that the thruster or ion beam source fulfills the requested mission or application requirements, and it can provide parameters for thruster and plasma modeling. Moreover, there is a need for standardizing electric propulsion thruster diagnostics in order to make characterization results of different thrusters and also from measurements performed in different vacuum facilities reliable and comparable. Therefore, we have developed an advanced electric propulsion diagnostic (AEPD) platform, which allows a comprehensive in-situ characterization of electric propulsion thrusters (or ion beam sources) and could serve as a standard on-ground tool in the future. The AEPD platform uses a five-axis positioning system and provides the option to use diagnostic tools for beam characterization (Faraday probe, retarding potential analyzer, ExB probe, active thermal probe), for optical inspection (telemicroscope, triangular laser head), and for thermal characterization (pyrometer, thermocamera). Here we describe the capabilities of the diagnostic platform and provide first experimental results of the characterization of a gridded ion thruster RIT- μX.

  5. In situ growth of gold nanoparticles on Hg2+-binding M13 phages for mercury sensing.

    Science.gov (United States)

    Wang, Xiaoyan; Yang, Ting; Zhang, Xiaoxiao; Chen, Mingli; Wang, Jianhua

    2017-11-09

    Mercury poses a serious threat to human health and the ecosystem. Its pollution is still prevalent in developing areas, which calls for the development of a simple on-site method for Hg 2+ detection. Plasmonic nanosensors for mercury, especially those based on gold nanoparticles (AuNPs), have been increasingly developed due to the flourish of nanotechnology in the last decade. However, the limitation on either selectivity or stability hindered their practical applications. Herein, by taking advantage of the unique optical properties of AuNPs and the versatility of M13 phages, a novel Hg 2+ sensing strategy is proposed. AuNPs grew in situ on the surface of Hg 2+ -binding M13 phages at room temperature and the resulting AuNP-phage networks were directly used for mercury sensing. Hg 2+ was selectively captured by M13 phages indwelling in the networks and gathered around AuNPs, followed by the reduction into Hg(0) and deposition on the AuNP surfaces, wherein it resulted in a blue shift of the SPR band of AuNPs and an increase in the absorbance. An LOD of 8 × 10 -8 mol L -1 was achieved based on the quantification of the absorption ratio of AuNPs at 525 and 650 nm. As the Hg 2+ recognition was double guaranteed by the capture of Hg 2+ -binding phages as well as the unique affinity between mercury and gold, the sensing system showed a high selectivity and a superior interference tolerance capability, facilitating its practical applications in environmental water bodies without deterioration of the sensing performance.

  6. Nanoparticle Metamorphosis: An in Situ High-Temperature Transmission Electron Microscopy Study of the Structural Evolution of Heterogeneous Au:Fe 2 O 3 Nanoparticles

    KAUST Repository

    Baumgardner, William J.

    2014-05-27

    High-temperature in situ electron microscopy and X-ray diffraction have revealed that Au and Fe2O3 particles fuse in a fluid fashion at temperatures far below their size-reduced melting points. With increasing temperature, the fused particles undergo a sequence of complex structural transformations from surface alloy to phase segregated and ultimately core-shell structures. The combination of in situ electron microscopy and spectroscopy provides insights into fundamental thermodynamic and kinetic aspects governing the formation of heterogeneous nanostructures. The observed structural transformations present an interesting analogy to thin film growth on the curved surface of a nanoparticle. Using single-particle observations, we constructed a phase diagram illustrating the complex relationships among composition, morphology, temperature, and particle size. © 2014 American Chemical Society.

  7. In-situ synthesis of Ag nanoparticles by electron beam irradiation

    International Nuclear Information System (INIS)

    Gong, Jiangfeng; Liu, Hongwei; Jiang, Yuwen; Yang, Shaoguang; Liao, Xiaozhou; Liu, Zongwen; Ringer, Simon

    2015-01-01

    Ag nanoparticles were synthesized by electron beam irradiation in the transmission electron microscope chamber at room temperature and the growth mechanism was explored in detail. The sizes of the Ag nanoparticles are controlled by the electron beam current density. Two nanoparticle growth stages were identified. The first growth stage was dominated by the discharging effect, while the second stage was controlled by the heating effect. The nanoparticle synthesis method should be applicable to the synthesis of other metallic nanoparticles. - Highlights: • Ag nanoparticles were synthesized by electron beam irradiation in the transmission electron microscope chamber. • The sizes of the Ag nanoparticles are controlled by the electron beam current density. • The growth mechanism was studied, two growth stages were confirmed. • The first growth stage was dominated by the discharging effect, and the second stage was controlled by the heating effect.

  8. In-situ synthesis of Ag nanoparticles by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jiangfeng, E-mail: jfgong@hhu.edu.cn [Department of Physics, College of Science, Hohai University, Nanjing 210093 (China); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Liu, Hongwei [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia); Jiang, Yuwen; Yang, Shaoguang [National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China); Liao, Xiaozhou, E-mail: xiaozhou.liao@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Liu, Zongwen [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia); School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Ringer, Simon [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia)

    2015-12-15

    Ag nanoparticles were synthesized by electron beam irradiation in the transmission electron microscope chamber at room temperature and the growth mechanism was explored in detail. The sizes of the Ag nanoparticles are controlled by the electron beam current density. Two nanoparticle growth stages were identified. The first growth stage was dominated by the discharging effect, while the second stage was controlled by the heating effect. The nanoparticle synthesis method should be applicable to the synthesis of other metallic nanoparticles. - Highlights: • Ag nanoparticles were synthesized by electron beam irradiation in the transmission electron microscope chamber. • The sizes of the Ag nanoparticles are controlled by the electron beam current density. • The growth mechanism was studied, two growth stages were confirmed. • The first growth stage was dominated by the discharging effect, and the second stage was controlled by the heating effect.

  9. Cell penetrating peptides: efficient vectors for delivery of nanoparticles, nanocarriers, therapeutic and diagnostic molecules.

    Science.gov (United States)

    Farkhani, Samad Mussa; Valizadeh, Alireza; Karami, Hadi; Mohammadi, Samane; Sohrabi, Nasrin; Badrzadeh, Fariba

    2014-07-01

    Efficient delivery of therapeutic and diagnostic molecules to the cells and tissues is a difficult challenge. The cellular membrane is very effective in its role as a selectively permeable barrier. While it is essential for cell survival and function, also presents a major barrier for intracellular delivery of cargo such as therapeutic and diagnostic agents. In recent years, cell-penetrating peptides (CPPs), that are relatively short cationic and/or amphipathic peptides, received great attention as efficient cellular delivery vectors due to their intrinsic ability to enter cells and mediate uptake of a wide range of macromolecular cargo such as plasmid DNA (pDNA), small interfering RNA (siRNAs), drugs, and nanoparticulate pharmaceutical carriers. This review discusses the various uptake mechanisms of these peptides. Furthermore, we discuss recent advances in the use of CPP for the efficient delivery of nanoparticles, nanocarriers, DNA, siRNA, and anticancer drugs to the cells. In addition, we have been highlighting new results for improving endosomal escape of CPP-cargo molecules. Finally, pH-responsive and activable CPPs for tumor-targeting therapy have been described. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. FAR-TECH's Nanoparticle Plasma Jet System and its Application to Disruptions, Deep Fueling, and Diagnostics

    Science.gov (United States)

    Thompson, J. R.; Bogatu, I. N.; Galkin, S. A.; Kim, J. S.

    2012-10-01

    Hyper-velocity plasma jets have potential applications in tokamaks for disruption mitigation, deep fueling and diagnostics. Pulsed power based solid-state sources and plasma accelerators offer advantages of rapid response and mass delivery at high velocities. Fast response is critical for some disruption mitigation scenario needs, while high velocity is especially important for penetration into tokamak plasma and its confining magnetic field, as in the case of deep fueling. FAR-TECH is developing the capability of producing large-mass hyper-velocity plasma jets. The prototype solid-state source has produced: 1) >8.4 mg of H2 gas only, and 2) >25 mg of H2 and >180 mg of C60 in a H2/C60 gas mixture. Using a coaxial plasma gun coupled to the source, we have successfully demonstrated the acceleration of composite H/C60 plasma jets, with momentum as high as 0.6 g.km/s, and containing an estimated C60 mass of ˜75 mg. We present the status of FAR-TECH's nanoparticle plasma jet system and discuss its application to disruptions, deep fueling, and diagnostics. A new TiH2/C60 solid-state source capable of generating significantly higher quantities of H2 and C60 in <0.5 ms will be discussed.

  11. Mesoporous MEL, BEA, and FAU zeolite crystals obtained by in situ formation of carbon template over metal nanoparticles

    DEFF Research Database (Denmark)

    Abildstrøm, Jacob Oskar; Ali, Zahra Nasrudin; Mentzel, Uffe Vie

    2016-01-01

    Here, we report the synthesis and characterization of hierarchical zeolite materials with MEL, BEA and FAU structures. The synthesis is based on the carbon templating method with an in situ-generated carbon template. Through the decomposition of methane and deposition of coke over nickel...... nanoparticles supported on silica, a carbon–silica composite is obtained and exploited as a combined carbon template/silica source for the zeolite synthesis. The mesoporous zeolite materials were all prepared by hydrothermal crystallization in alkaline media followed by removal of the carbon template...

  12. Fingermark detection based on the in situ growth of luminescent nanoparticles--towards a new generation of multimetal deposition.

    Science.gov (United States)

    Becue, Andy; Scoundrianos, Aurèle; Champod, Christophe; Margot, Pierre

    2008-07-18

    The in situ deposition of zinc oxide on gold nanoparticles in aqueous solution has been here successfully applied in the field of fingermark detection on various non-porous surfaces. In this article, we present the improvement of the multimetal deposition, an existing technique limited up to now to non-luminescent results, by obtaining luminescent fingermarks with very good contrast and details. This is seen as a major improvement in the field in terms of selectivity and sensitivity of detection, especially on black surfaces.

  13. One pot in situ growth of gold nanoparticles on amine-modified graphene oxide and their high catalytic properties

    Science.gov (United States)

    Ju, Yuyun; Li, Xi; Feng, Jie; Ma, Yanhua; Hu, Jing; Chen, Xingguo

    2014-10-01

    In this work, one pot strategy was proposed for in situ growth of Au nanoparticles (Au NPs) on the surface of amine-modified graphene oxide (GO@NH2) nanosheets. Au NPs were generated via an in situ reduction of Au3+ by Cu+ which was linked to the surface of GO@NH2 nanosheets through inorganic grafting. The initial Au NPs then served as seed for subsequent particle growth. The as-obtained GO@NH2-Au nanocomposites (GO@NH2-Au NCs) exhibited high catalytic activity for the degradation of 4-nitrophenol, which was a refractory pollutant that occur in industrial waste water. The catalytic efficiency was examined by turnover frequency (TOF). It was calculated to be 595 h-1, which was higher than that of other Au catalysts. Furthermore, the as-prepared catalyst showed high cycle stabilization during the catalytic reduction.

  14. In situ titanium dioxide nanoparticles quantitative microscopy in cells and in C. elegans using nuclear microprobe analysis

    Energy Technology Data Exchange (ETDEWEB)

    Le Trequesser, Quentin [Université de Bordeaux, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, UMR 5797, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Saez, Gladys; Devès, Guillaume; Michelet, Claire; Barberet, Philippe [Université de Bordeaux, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, UMR 5797, CENBG, Chemin du solarium, 33175 Gradignan (France); Delville, Marie-Hélène [CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Seznec, Hervé, E-mail: herve.seznec@cenbg.in2p3.fr [Université de Bordeaux, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, UMR 5797, CENBG, Chemin du solarium, 33175 Gradignan (France)

    2014-12-15

    Detecting and tracking nanomaterials in biological systems is challenging and essential to understand the possible interactions with the living. In this context, in situ analyses were conducted on human skin cells and a multicellular organism (Caenorhabditiselegans) exposed to titanium dioxide nanoparticles (TiO{sub 2} NPs) using nuclear microprobe. Coupled to conventional methods, nuclear microprobe was found to be suitable for accurate description of chemical structure of biological systems and also for detection of native TiO{sub 2} NPs. The method presented herein opens the field to NPs exposure effects analyses and more generally to toxicological analyses assisted by nuclear microprobe. This method will show applications in key research areas where in situ imaging of chemical elements is essential.

  15. Potentiometric in Situ Monitoring of Anions in the Synthesis of Copper and Silver Nanoparticles Using the Polyol Process.

    Science.gov (United States)

    Carey, Jesse L; Whitcomb, David R; Chen, Suyue; Penn, R Lee; Bühlmann, Philippe

    2015-12-22

    Potentiometric sensors, such as polymeric membrane, ion-selective electrodes (ISEs), have been used in the past to monitor a variety of chemical processes. However, the use of these sensors has traditionally been limited to aqueous solutions and moderate temperatures. Here we present an ISE with a high-capacity ion-exchange sensing membrane for measurements of nitrate and nitrite in the organic solvent propylene glycol at 150 °C. It is capable of continuously measuring under these conditions for over 180 h. We demonstrate the usefulness of this sensor by in situ monitoring of anion concentrations during the synthesis of copper and silver nanoparticles in propylene glycol using the polyol method. Ion chromatography and a colorimetric method were used to independently confirm anion concentrations measured in situ. In doing so, it was shown that in this reaction the co-ion nitrate is reduced to nitrite.

  16. Hybrid Perovskite Thin-Film Photovoltaics: In Situ Diagnostics and Importance of the Precursor Solvate Phases

    KAUST Repository

    Munir, Rahim

    2016-11-07

    Solution-processed hybrid perovskite semiconductors attract a great deal of attention, but little is known about their formation process. The one-step spin-coating process of perovskites is investigated in situ, revealing that thin-film formation is mediated by solid-state precursor solvates and their nature. The stability of these intermediate phases directly impacts the quality and reproducibility of thermally converted perovskite films and their photovoltaic performance.

  17. Remarkable efficiency of phosphate removal: Ferrate(VI)-induced in situ sorption on core-shell nanoparticles.

    Science.gov (United States)

    Kralchevska, Radina P; Prucek, Robert; Kolařík, Jan; Tuček, Jiří; Machala, Libor; Filip, Jan; Sharma, Virender K; Zbořil, Radek

    2016-10-15

    Despite the importance of phosphorus as a nutrient for humans and its role in ecological sustainability, its high abundance, resulting in large part from human activities, causes eutrophication that negatively affects the environment and public health. Here, we present the use of ferrate(VI) as an alternative agent for removing phosphorus from aqueous media. We address the mechanism of phosphate removal as a function of the Fe/P mass ratio and the pH value of the solution. The isoelectric point of γ-Fe2O3 nanoparticles, formed as dominant Fe(VI) decomposition products, was identified to play a crucial role in predicting their efficiency in removing of phosphates. Importantly, it was found that the removal efficiency dramatically changes if Fe(VI) is added before (ex-situ conditions) or after (in-situ conditions) the introduction of phosphates into water. Removal under in-situ conditions showed remarkable sorption capacity of 143.4 mg P per gram of ferric precipitates due to better accessibility of active surface sites on in-situ formed ferric oxides/oxyhydroxides. At pH = 6.0-7.0, complete removal of phosphates was observed at a relatively low Fe/P mass ratio (5:1). The results show that phosphates are removed from water solely by sorption on the surface of γ-Fe2O3/γ-FeOOH core/shell nanoparticles. The advantages of Fe(VI) utilization include its environmentally friendly nature, the possibility of easy separation of the final product from water by a magnetic field or by natural settling, and the capacity for successful phosphate elimination at pH values near the neutral range and at low Fe/P mass ratios. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Highly stable noble-metal nanoparticles in tetraalkylphosphonium ionic liquids for in situ catalysis.

    Science.gov (United States)

    Banerjee, Abhinandan; Theron, Robin; Scott, Robert W J

    2012-01-09

    Gold and palladium nanoparticles were prepared by lithium borohydride reduction of the metal salt precursors in tetraalkylphosphonium halide ionic liquids in the absence of any organic solvents or external nanoparticle stabilizers. These colloidal suspensions remained stable and showed no nanoparticle agglomeration over many months. A combination of electrostatic interactions between the coordinatively unsaturated metal nanoparticle surface and the ionic-liquid anions, bolstered by steric protection offered by the bulky alkylated phosphonium cations, is likely to be the reason behind such stabilization. The halide anion strongly absorbs to the nanoparticle surface, leading to exceptional nanoparticle stability in halide ionic liquids; other tetraalkylphosphonium ionic liquids with non-coordinating anions, such as tosylate and hexafluorophosphate, show considerably lower affinities towards the stabilization of nanoparticles. Palladium nanoparticles stabilized in the tetraalkylphosphonium halide ionic liquid were stable, efficient, and recyclable catalysts for a variety of hydrogenation reactions at ambient pressures with sustained activity. Aerial oxidation of the metal nanoparticles occurred over time and was readily reversed by re-reduction of oxidized metal salts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Nanoparticle-triggered in situ catalytic chemical reactions for tumour-specific therapy.

    Science.gov (United States)

    Lin, Han; Chen, Yu; Shi, Jianlin

    2018-03-21

    Tumour chemotherapy employs highly cytotoxic chemodrugs, which kill both cancer and normal cells by cellular apoptosis or necrosis non-selectively. Catalysing/triggering the specific chemical reactions only inside tumour tissues can generate abundant and special chemicals and products locally to initiate a series of unique biological and pathologic effects, which may enable tumour-specific theranostic effects to combat cancer without bringing about significant side effects on normal tissues. Nevertheless, chemical reaction-initiated selective tumour therapy strongly depends on the advances in chemistry, materials science, nanotechnology and biomedicine. This emerging cross-disciplinary research area is substantially different from conventional cancer-theranostic modalities in clinics. In response to the fast developments in cancer theranostics based on intratumoural catalytic chemical reactions, this tutorial review summarizes the very-recent research progress in the design and synthesis of representative nanoplatforms with intriguing nanostructures, compositions, physiochemical properties and biological behaviours for versatile catalytic chemical reaction-enabled cancer treatments, mainly by either endogenous tumour microenvironment (TME) triggering or exogenous physical irradiation. These unique intratumoural chemical reactions can be used in tumour-starving therapy, chemodynamic therapy, gas therapy, alleviation of tumour hypoxia, TME-responsive diagnostic imaging and stimuli-responsive drug release, and even externally triggered versatile therapeutics. In particular, the challenges and future developments of such a novel type of cancer-theranostic modality are discussed in detail to understand the future developments and prospects in this research area as far as possible. It is highly expected that this kind of unique tumour-specific therapeutics by triggering specific in situ catalytic chemical reactions inside tumours would provide a novel but efficient

  20. Development of in situ cleaning techniques for diagnostic mirrors in ITER

    International Nuclear Information System (INIS)

    Litnovsky, A.; Laengner, M.; Matveeva, M.; Schulz, Ch.; Marot, L.; Voitsenya, V.S.; Philipps, V.; Biel, W.; Samm, U.

    2011-01-01

    Mirrors will be used in all optical and laser-based diagnostic systems of ITER. In the severe environment, the optical characteristics of mirrors will be degraded, hampering the entire performance of the respective diagnostics. A minute impurity deposition of 20 nm of carbon on the mirror is sufficient to decrease the mirror reflectivity by tens of percent outlining the necessity of the mirror cleaning in ITER. The results of R and D on plasma cleaning of molybdenum diagnostic mirrors are reported. The mirrors contaminated with amorphous carbon films in the laboratory conditions and in the tokamaks were cleaned in steady-state hydrogenic plasmas. The maximum cleaning efficiency of 4.2 nm/min was reached for the laboratory and soft tokamak hydrocarbon films, whereas for the hard tokamak films the carbidization of mirrors drastically decreased the cleaning efficiency down to 0.016 nm/min. This implies the necessity of sputtering cleaning of contaminated mirrors as the only reliable tool to remove the deposits by plasma cleaning. An overview of R and D program on mirror cleaning is provided along with plans for further studies and the recommendations for ITER mirror-based diagnostics.

  1. Antibacterial and hemolysis activity of polypyrrole nanotubes decorated with silver nanoparticles by an in-situ reduction process.

    Science.gov (United States)

    Upadhyay, J; Kumar, A; Gogoi, B; Buragohain, A K

    2015-09-01

    Polypyrrole nanotube-silver nanoparticle nanocomposites (PPy-NTs:Ag-NPs) have been synthesized by in-situ reduction of silver nitrate (AgNO3) to suppress the agglomeration of Ag-NPs. The morphology and chemical structure of the nanocomposites have been studied by HRTEM, SEM, XRD, FTIR and UV-vis spectroscopy. The average diameter of the polypyrrole nanotubes (PPy-NTs) is measured to be 130.59±5.5 nm with their length in the micrometer range, while the silver nanoparticles (Ag-NPs) exhibit spherical shape with an average diameter of 23.12±3.23 nm. In-vitro blood compatibility of the nanocomposites has been carried out via hemolysis assay. Antimicrobial activity of the nanocomposites has been investigated with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. The results depict that the hemolysis and antimicrobial activities of the nanocomposites increase with increasing Ag-NP concentration that can be controlled by the AgNO3 precursor concentration in the in-situ process. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Preparation and properties of cellulose nanocomposite films with in situ generated copper nanoparticles using Terminalia catappa leaf extract.

    Science.gov (United States)

    Muthulakshmi, L; Rajini, N; Nellaiah, H; Kathiresan, T; Jawaid, M; Rajulu, A Varada

    2017-02-01

    In the present work, copper nanoparticles (CuNPs) were in situ generated inside cellulose matrix using Terminalia catappa leaf extract as a reducing agent. During this process, some CuNPs were also formed outside the matrix. The CuNPs formed outside the matrix were observed with transmission electron microscope (TEM) and scanning electron microscope (SEM). Majority of the CuNPs formed outside the matrix were in the size range of 21-30nm. The cellulose/CuNP composite films were characterized by Fourier transform infrared spectroscopic, X-Ray diffraction and thermogravimetric techniques. The crystallinity of the cellulose/CuNP composite films was found to be lower than that of the matrix indicating rearrangement of cellulose molecules by in situ generated CuNPs. Further, the expanded diffractogram of the composite films indicated the presence of a mixture of Cu, CuO and Cu 2 O nanoparticles. The thermal stability of the composites was found to be lower than that of the composites upto 350°C beyond which a reverse trend was observed. This was attributed to the catalytic behaviour of CuNPs for early degradation of the composites. The composite films possessed sufficient tensile strength which can replace polymer packaging films like polyethylene. Further, the cellulose/CuNP composite films exhibited good antibacterial activity against E.coli bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Towards Theranostic Multicompartment Microcapsules: in-situ Diagnostics and Laser-induced Treatment

    Science.gov (United States)

    Xiong, Ranhua; Soenen, Stefaan J.; Braeckmans, Kevin; Skirtach, Andre G.

    2013-01-01

    Paving the way towards the application of polyelectrolyte multilayer capsules in theranostics, we describe diagnostic multi-functionality and drug delivery using multicompartment polymeric capsules which represent the next generation of drug delivery carriers. Their versatility is particularly important for potential applications in the area of theranostics wherein the carriers are endowed with the functionality for both diagnostics and therapy. Responsiveness towards external stimuli is attractive for providing controlled and on-demand release of encapsulated materials. An overview of external stimuli is presented with an emphasis on light as a physical stimulus which has been widely used for activation of microcapsules and release of their contents. In this article we also describe existing and new approaches to build multicompartment microcapsules as well as means available to achieve controlled and triggered release from their subcompartments, with a focus on applications in theranostics. Outlook for future directions in the area are highlighted. PMID:23471141

  4. Rapid colorimetric sensing of tetracycline antibiotics with in situ growth of gold nanoparticles

    International Nuclear Information System (INIS)

    Shen, Li; Chen, Jing; Li, Na; He, Pingli; Li, Zhen

    2014-01-01

    Highlights: • Tetracyclines directly reduce aurate into gold nanoparticles. • Gold nanoparticles showed characteristic plamson absorbance at 526 nm. • Quantitative detection of tetracyclines with the colorimetric assay. • Tetracyclines spiked urine samples can be detected with the assay. - Abstract: A colorimetric assay utilizing the formation of gold nanoparticles was developed to detect tetracycline antibiotics in fluidic samples. Tetracycline antibiotics showed the capability of directly reducing aurate salts into atomic gold which form gold nanoparticles spontaneously under proper conditions. The resulted gold nanoparticles showed characteristic plasmon absorbance at 526 nm, which can be visualized by naked eyes or with a spectrophotometer. UV–vis absorbance of the resulted gold nanoparticles is correlated directly with the concentrations of tetracycline antibiotics in the solution, allowing for quantitative colorimetric detection of tetracycline antibiotics. Reaction conditions, such as pH, temperature, reaction time, and ionic strength were optimized. Sensitivity of the colorimetric assay can be enhanced by the addition of gold nanoparticle seeds, a LOD as low as 20 ng mL −1 can be achieved with the help of seed particles. The colorimetric assay showed minimum interference from ethanol, methanol, urea, glucose, and other antibiotics such as sulfonamides, amino glycosides etc. Validity of the method was also evaluated on urine samples spiked with tetracycline antibiotics. The method provides a broad spectrum detection method for rapid and sensitive detection of reductive substances such as tetracycline antibiotics in liquid and biological samples

  5. Highly-sensitive detection of Salmonella typhi in clinical blood samples by magnetic nanoparticle-based enrichment and in-situ measurement of isothermal amplification of nucleic acids.

    Science.gov (United States)

    Kaur, Avinash; Kapil, Arti; Elangovan, Ravikrishnan; Jha, Sandeep; Kalyanasundaram, Dinesh

    2018-01-01

    Enteric fever continues to be a major cause of mortality and morbidity globally, particularly in poor resource settings. Lack of rapid diagnostic assays is a major driving factor for the empirical treatment of enteric fever. In this work, a rapid and sensitive method 'Miod' 'has been developed. Miod includes a magnetic nanoparticle-based enrichment of target bacterial cells, followed by cell lysis and loop-mediated isothermal amplification (LAMP) of nucleic acids for signal augmentation along with concurrent measurement of signal via an in-situ optical detection system. To identify positive/negative enteric fever infections in clinical blood samples, the samples were processed using Miod at time = 0 hours and time = 4 hours post-incubation in blood culture media. Primers specific for the STY2879 gene were used to amplify the nucleic acids isolated from S. typhi cells. A limit of detection of 5 CFU/mL was achieved. No cross-reactivity of the primers were observed against 106 CFU/mL of common pathogenic bacterial species found in blood such as E. coli, P. aeruginosa, S. aureus, A. baumanni, E. faecalis, S. Paratyphi A and K. pneumonia. Miod was tested on 28 human clinical blood samples. The detection of both pre-and post-four-hours incubation confirmed the presence of viable S. typhi cells and allowed clinical correlation of infection. The positive and negative samples were successfully detected in less than 6 hours with 100% sensitivity and specificity.

  6. In situ synthesis of Eu(Tp){sub 3} complex inside the pores of mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Malba, Chandrashekhar; Bellotto, Luca; Freris, Isidora [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, via Torino 155/b, 30170 Venezia-Mestre (Italy); Enrichi, Francesco [CIVEN, Coordinamento Interuniversitario Veneto per le Nanotecnologie, Via delle Industrie 5, 30175 Marghera (Venezia) (Italy); Cristofori, Davide [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, via Torino 155/b, 30170 Venezia-Mestre (Italy); Riello, Pietro, E-mail: riellop@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, via Torino 155/b, 30170 Venezia-Mestre (Italy); Benedetti, Alvise [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, via Torino 155/b, 30170 Venezia-Mestre (Italy)

    2013-10-15

    A route for europium (III) tris-pyrazolyl borate complex [Eu(Tp){sub 3}] formation inside the pores of mesoporous silica nanoparticles (MSNs) has been established to yield a highly luminescent nanostructured hybrid. Two different in situ chemical precipitation techniques have been explored for the nanoencapsulation of the Eu{sup 3+} complex [Eu(Tp){sub 3}] inside the pore channels of mesoporous silica nanoparticles, by varying the sequence order of precursor impregnation. In the first method, the Eu salt is introduced into the pores by wet impregnation and removal of the solvent, followed by wet impregnation of the ligand. In the second approach, the addition sequence is reversed. The importance of the addition sequence was demonstrated by the successful formation of the europium (III) tris-pyrazolyl borate complex in the pore network by following the first approach. The observed pyrazol-1-yl borate (Tp) to Eu{sup 3+} intramolecular energy transfer, i.e., the antenna effect, verified the formation of the complex. Photoluminescence spectroscopy, X-ray diffraction, N{sub 2} adsorption, FTIR spectroscopy, and TEM were used to characterize the material. -- Highlights: • In situ formation of Eu(Tp){sub 3} in mesoporous silica nanoparticles is studied. • Pivotal role of the addition sequence of the reagents is demonstrated. • Eu salt adsorption preceded the addition of the ligand proved effective (route A). • Luminescent material is well characterized by several techniques. • We give a possible mechanism for the formation of Eu(Tp){sub 3} complex via route A.

  7. Platinum Iron Intermetallic Nanoparticles Supported on Carbon Formed In Situ by High-Pressure Pyrolysis for Efficient Oxygen Reduction

    DEFF Research Database (Denmark)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei

    2016-01-01

    Carbon-supported PtFe alloy catalysts are synthesized by the one-step, high-temperature pyrolysis of Pt, Fe, and C precursors. As a result of the high temperature, the formed PtFe nanoparticles possess highly ordered, face-centered tetragonal, intermetallic structures with a mean size of ≈11.8 nm....... At 0.9 V versus the reversible hydrogen electrode, the PtFe nanoparticles show a 6.8 times higher specific activity than the reference Pt/C catalyst towards the oxygen reduction reaction (ORR) as well as excellent stability, most likely because of the durable intermetallic structure and the preleaching...... treatment of the catalyst. During these preliminary syntheses, we found that a portion of the PtFe nanoparticles is buried in the in situ formed carbon phase, which limits Pt utilization in the catalyst and results in a mass-specific activity equivalent to the commercial Pt/C catalyst. Moreover...

  8. Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Guo Xiaojun, E-mail: guoxj6906@163.com [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China); Zhao Leihua; Zhang Li; Li Jing [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China)

    2012-01-15

    Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108 Degree-Sign and a well dispersion.

  9. In situ environmental TEM studies of dynamic changes in cerium-based oxides nanoparticles during redox processes.

    Science.gov (United States)

    Crozier, Peter A; Wang, Ruigang; Sharma, Renu

    2008-10-01

    We apply in situ environmental transmission electron microscopy (ETEM) to study the dynamic changes taking place during redox reactions in ceria and ceria-zirconia nanoparticles in a hydrogen atmosphere. For pure ceria, we find that a reversible phase transformation takes place at 730 degrees C in which oxygen vacancies introduced during reduction order to give a cubic superstructure with a periodicity of roughly twice the basic fluorite lattice. We also observe the structural transformations taking place on the surface during reduction in hydrogen. The (110) ceria surface is initially constructed with a series of low-energy (111) nanofacets. Under strong reduction, the surface slowly transforms to a smooth (110) surface which was not observed to change upon re-oxidation. The surface transformation allows the reduced surface to accommodate a high concentration of oxygen vacancies without creating a strong perpendicular dipole moment. In the ceria-zirconia system, we are able to use ETEM to follow the redox activity of individual nanoparticles and correlate this property with structure and composition. We find considerable variation in the redox activity and interpret this in terms of structural differences between the nanoparticles.

  10. Functionalized TiO2 nanoparticles for use for in-situ anion immobilization

    International Nuclear Information System (INIS)

    Mattigod, Shas V.; Fryxell, Glen E.; Alford, Kentin L.; Gilmore, Tyler J.; Parker, Kent E.; Serne, R JEFFREY.; Engelhard, Mark H.

    2005-01-01

    40-60 nm anatase nanoparticles were coated with an organosilane monolayer terminated with an ethylenediamine (EDA) ligand. This functionalized nanoparticle (FNP) was then treated with an aqueous solution of Cu(II) to create a cationic Cu-EDA complex bound to the nanoparticle surface. The Cu-EDA FNP was then studied for its binding affinity for pertechnetate anion from a Hanford groundwater matrix. The Cu-EDA FNP was also evaluated for its injectability into a porous medium for possible application as a subsurface semi-permeable reactive barrier. Injection was readily accomplished, and resulted in a highly uniform distribution of the FNP sorbent in the test column

  11. Adhesion enhancement of biomimetic dry adhesives by nanoparticle in situ synthesis

    International Nuclear Information System (INIS)

    Díaz Téllez, J P; Harirchian-Saei, S; Li, Y; Menon, C

    2013-01-01

    A novel method to increase the adhesion strength of a gecko-inspired dry adhesive is presented. Gold nanoparticles are synthesized on the tips of the microfibrils of a polymeric dry adhesive to increase its Hamaker constant. Formation of the gold nanoparticles is qualitatively studied through a colour change in the originally transparent substance and quantitatively analysed using ultraviolet–visible spectrophotometry. A pull-off force test is employed to quantify the adhesion enhancement. Specifically, adhesion forces of samples with and without embedded gold nanoparticles are measured and compared. The experimental results indicate that an adhesion improvement of 135% can be achieved. (paper)

  12. Revealing correlation of valence state with nanoporous structure in cobalt catalyst nanoparticles by in situ environmental TEM.

    Science.gov (United States)

    Xin, Huolin L; Pach, Elzbieta A; Diaz, Rosa E; Stach, Eric A; Salmeron, Miquel; Zheng, Haimei

    2012-05-22

    Simultaneously probing the electronic structure and morphology of materials at the nanometer or atomic scale while a chemical reaction proceeds is significant for understanding the underlying reaction mechanisms and optimizing a materials design. This is especially important in the study of nanoparticle catalysts, yet such experiments have rarely been achieved. Utilizing an environmental transmission electron microscope equipped with a differentially pumped gas cell, we are able to conduct nanoscopic imaging and electron energy loss spectroscopy in situ for cobalt catalysts under reaction conditions. Studies reveal quantitative correlation of the cobalt valence states with the particles' nanoporous structures. The in situ experiments were performed on nanoporous cobalt particles coated with silica, while a 15 mTorr hydrogen environment was maintained at various temperatures (300-600 °C). When the nanoporous particles were reduced, the valence state changed from cobalt oxide to metallic cobalt and concurrent structural coarsening was observed. In situ mapping of the valence state and the corresponding nanoporous structures allows quantitative analysis necessary for understanding and improving the mass activity and lifetime of cobalt-based catalysts, for example, for Fischer-Tropsch synthesis that converts carbon monoxide and hydrogen into fuels, and uncovering the catalyst optimization mechanisms.

  13. In situ decoration of graphene sheets with gold nanoparticles synthetized by pulsed laser ablation in liquids

    OpenAIRE

    Torres-Mendieta, Rafael; Ventura-Espinosa, David; Sabater, Sara; Lancis, Jesus; M?nguez-Vega, Gladys; Mata, Jose A.

    2016-01-01

    The demand for nanocomposites of graphene and carbonaceous materials decorated with metallic nanoparticles is increasing on account of their applications in science and technology. Traditionally, the production of graphene-metal assemblies is achieved by the non-environmentally friendly reduction of metallic salts in carbonaceous suspensions. However, precursor residues during nanoparticle growth may reduce their surface activity and promote cross-chemical undesired effects. In this work we p...

  14. In situ generation of highly dispersed metal nanoparticles on two-dimensional layered SiO2 by topotactic structure conversion and their superior catalytic activity

    Science.gov (United States)

    Chen, Zhe; Jia, Da-Shuang; Zhou, Yue; Hao, Jiang; Liang, Yu; Cui, Zhi-Min; Song, Wei-Guo

    2018-03-01

    Metal nanoparticles such as Ag, Cu and Fe are effective catalysts for many reactions, whereas a facile method to prepare metal nanoparticles with high uniformed dispersion is still desirable. Herein, the topotactic structure conversion of layered silicate, RUB-15, was utilized to support metal nanoparticles. Through simple ion-exchange and following calcination step, metal nanoparticles were generated in situ inside the interlayer space of layered silica, and the topotactic structure conversion process assured nano-sized and highly uniformed dispersion of metal nanoparticles. The obtained Ag/SiO2 composite showed superior catalytic activity for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB), with a rate constant as high as 0.0607 s-1 and 0.0778 s-1. The simple and universal synthesis method as well as high activity of the product composite endow the strategy good application prospect.

  15. Priming nanoparticle-guided diagnostics and therapeutics towards human organs-on-chips microphysiological system

    Science.gov (United States)

    Choi, Jin-Ha; Lee, Jaewon; Shin, Woojung; Choi, Jeong-Woo; Kim, Hyun Jung

    2016-10-01

    Nanotechnology and bioengineering have converged over the past decades, by which the application of multi-functional nanoparticles (NPs) has been emerged in clinical and biomedical fields. The NPs primed to detect disease-specific biomarkers or to deliver biopharmaceutical compounds have beena validated in conventional in vitro culture models including two dimensional (2D) cell cultures or 3D organoid models. However, a lack of experimental models that have strong human physiological relevance has hampered accurate validation of the safety and functionality of NPs. Alternatively, biomimetic human "Organs-on-Chips" microphysiological systems have recapitulated the mechanically dynamic 3D tissue interface of human organ microenvironment, in which the transport, cytotoxicity, biocompatibility, and therapeutic efficacy of NPs and their conjugates may be more accurately validated. Finally, integration of NP-guided diagnostic detection and targeted nanotherapeutics in conjunction with human organs-on-chips can provide a novel avenue to accelerate the NP-based drug development process as well as the rapid detection of cellular secretomes associated with pathophysiological processes.

  16. Quantum Mechanics of In Situ Synthesis of Metal Nanoparticles within Anionic Microgels

    Directory of Open Access Journals (Sweden)

    Mirza Wasif Baig

    2013-01-01

    Full Text Available We discuss the quantum mechanics of many-body systems, that is, hybrid microgel consisting of negatively charged anionic microgels possessing thick sheath of water molecules solvating protruding anionic moieties and nanoparticle captivated within the microgel. Thermodynamic feasibility of synthesis of particular nanoparticle within the microgel is dependent upon the magnitude of interaction between nanoparticle, water molecules, and microgel relative to sum of magnitude of self-interaction between counterions and interaction between counterions and microgel. Nanoparticles synthesized with in the microgels have thick electronic cloud that oscillates under the influence of net interaction potential of charged anionic moieties and solvent water molecules which constitutes the chemical environment of hybrid microgel. Hamiltonian describing energy of oscillating electronic cloud of wrapped around nanoparticle is mathematically derived to be equal to product of integral electron density and product of its position vector overall space and net force acting on the oscillating electronic cloud of nanoparticle is mathematically defined as; ℱ∫ρn{n}n^ dn.

  17. Nanoparticle penetration and transport in living pumpkin plants: in situ subcellular identification

    Directory of Open Access Journals (Sweden)

    Ibarra M Ricardo

    2009-04-01

    Full Text Available Abstract Background In recent years, the application of nanotechnology in several fields of bioscience and biomedicine has been studied. The use of nanoparticles for the targeted delivery of substances has been given special attention and is of particular interest in the treatment of plant diseases. In this work both the penetration and the movement of iron-carbon nanoparticles in plant cells have been analyzed in living plants of Cucurbita pepo. Results The nanoparticles were applied in planta using two different application methods, injection and spraying, and magnets were used to retain the particles in movement in specific areas of the plant. The main experimental approach, using correlative light and electron microscopy provided evidence of intracellular localization of nanoparticles and their displacement from the application point. Long range movement of the particles through the plant body was also detected, particles having been found near the magnets used to immobilize and concentrate them. Furthermore, cell response to the nanoparticle presence was detected. Conclusion Nanoparticles were capable of penetrating living plant tissues and migrating to different regions of the plant, although movements over short distances seemed to be favoured. These findings show that the use of carbon coated magnetic particles for directed delivery of substances into plant cells is a feasible application.

  18. In situ plasma cleaning of ITER diagnostic mirrors in noble-gas RF discharge

    Science.gov (United States)

    Dmitriev, A. M.; Babinov, N. A.; Bazhenov, A. N.; Bukreev, I. M.; Kochergin, M. M.; Koval, A. N.; Kurskiev, G. S.; Litvinov, A. E.; Masyukevich, S. V.; Mukhin, E. E.; Razdobarin, A. G.; Samsonov, D. S.; Solokha, V. V.; Tolstyakov, S. Yu; Andrew, P.; Leipold, F.; Shigin, P. A.; Reichle, R.; Bukhovets, V. L.; Gorodetsky, A. E.; Markin, A. V.; Zakharov, A. P.; Zalavutdinov, R. Kh; Chernakov, An P.; Chernakov, Al P.; Chernakov, P. V.; Chernoizumskaya, T. V.; Kobelev, A. A.; Smirnov, A. S.; Marzinovsky, I. A.

    2017-12-01

    The development of the first mirror cleaning and recovery system is one of the challenges for all optical diagnostics in ITER. This study is focused on capacitively coupled radio frequency (CCRF) discharge as a promising method for removal of metal deposits. The physical aspects of the RF discharge application are discussed with a focus on implementation under ITER conditions. The effective sputtering rates of Be, W and Mo were calculated as a function of applied frequency and absorbed power for noble gases—He, Ne, Ar, Kr, Xe, taking into account complex shape of the ion energy distribution function in the electrode sheaths. Helium is shown to be a good candidate for cleaning Mo mirrors from Be deposits in the frequency range ∼80–100 MHz and pressure of a few Pa.

  19. Diagnostics

    DEFF Research Database (Denmark)

    Donné, A.J.H.; Costley, A.E.; Barnsley, R.

    2007-01-01

    In order to support the operation of ITER and the planned experimental programme an extensive set of plasma and first wall measurements will be required. The number and type of required measurements will be similar to those made on the present-day large tokamaks while the specification...... of the measurements—time and spatial resolutions, etc—will in some cases be more stringent. Many of the measurements will be used in the real time control of the plasma driving a requirement for very high reliability in the systems (diagnostics) that provide the measurements. The implementation of diagnostic systems......&D is needed to prepare the systems. In some cases the environmental difficulties are so severe that new diagnostic techniques are required. The starting point in the development of diagnostics for ITER is to define the measurement requirements and develop their justification. It is necessary to include all...

  20. In situ synthesis of zero-valent silver nanoparticles in polymethylmethacrylate under high temperature

    International Nuclear Information System (INIS)

    Xiong Yuanlu; Luo Guoqiang; Chen Cheng; Yuan Huan; Shen Qiang; Li Meijuan

    2012-01-01

    In this work, the silver nanoparticles were synthesized in polymethylmethacrylate (PMMA) matrix under high temperature with polyvinylpyrrolidone (PVP) as additional stabilizer and N,N-dimethylformamide (DMF) as reaction medium. The UV-vis spectroscopy and transmission electron microscopy (TEM) were adopted to investigate the growth and shape conversion of Ag nanoparticles with the lacking of additional Ag source. The results showed that the stable zero-valent Ag in PMMA was obtained successfully. Two types of Ag nanoparticles, single-crystal and twinned ones, could form in the initial period. While the twinned ones will gradually disappear along with the reaction processed, the single-crystal ones could survive and slowly grow by consuming the Ag atoms which were etched form twinned ones. The single-crystal ones will take shape conversion from sphere to nanocube with nearly the same particle size after the total disappearance of twinned ones. The size and shape of Ag nanoparticles can be well controlled by reaction time. The high viscosity PMMA matrix plays the important role of controlling the growth of the Ag nanoparticles, and the PVP takes the responsibility of the shape conversion.

  1. Pyrite nanoparticles as a Fenton-like reagent for in situ remediation of organic pollutants

    Directory of Open Access Journals (Sweden)

    Carolina Gil-Lozano

    2014-06-01

    Full Text Available The Fenton reaction is the most widely used advanced oxidation process (AOP for wastewater treatment. This study reports on the use of pyrite nanoparticles and microparticles as Fenton reagents for the oxidative degradation of copper phthalocyanine (CuPc as a representative contaminant. Upon oxidative dissolution in water, pyrite (FeS2 particles can generate H2O2 at their surface while simultaneously promoting recycling of Fe3+ into Fe2+ and vice versa. Pyrite nanoparticles were synthesized by the hot injection method. The use of a high concentration of precursors gave individual nanoparticles (diameter: 20 nm with broader crystallinity at the outer interfaces, providing a greater number of surface defects, which is advantageous for generating H2O2. Batch reactions were run to monitor the kinetics of CuPc degradation in real time and the amount of H2O2. A markedly greater degradation of CuPc was achieved with nanoparticles as compared to microparticles: at low loadings (0.08 mg/L and 20 h reaction time, the former enabled 60% CuPc removal, whereas the latter enabled only 7% removal. These results confirm that the use of low concentrations of synthetic nanoparticles can be a cost effective alternative to conventional Fenton procedures for use in wastewater treatment, avoiding the potential risks caused by the release of heavy metals upon dissolution of natural pyrites.

  2. Electrical sintering of silver nanoparticle ink studied by in-situ TEM probing.

    Directory of Open Access Journals (Sweden)

    Magnus Hummelgård

    Full Text Available Metallic nanoparticle inks are used for printed electronics, but to reach acceptable conductivity the structures need to be sintered, usually using a furnace. Recently, sintering by direct resistive heating has been demonstrated. For a microscopic understanding of this Joule heating sintering method, we studied the entire process in real time inside a transmission electron microscope equipped with a movable electrical probe. We found an onset of Joule heating induced sintering and coalescence of nanoparticles at power levels of 0.1-10 mW/μm³. In addition, a carbonization of the organic shells that stabilize the nanoparticles were found, with a conductivity of 4 10⁵ Sm⁻¹.

  3. Mechanical characterization of diesel soot nanoparticles: in situ compression in a transmission electron microscope and simulations

    Science.gov (United States)

    Jenei, Istvan Zoltan; Dassenoy, Fabrice; Epicier, Thierry; Khajeh, Arash; Martini, Ashlie; Uy, Dairene; Ghaednia, Hamed; Gangopadhyay, Arup

    2018-02-01

    Incomplete fuel burning inside an internal combustion engine results in the creation of soot in the form of nanoparticles. Some of these soot nanoparticles (SNP) become adsorbed into the lubricating oil film present on the cylinder walls, which adversely affects the tribological performance of the lubricant. In order to better understand the mechanisms underlying the wear caused by SNPs, it is important to understand the behavior of SNPs and to characterize potential changes in their mechanical properties (e.g. hardness) caused by (or during) mechanical stress. In this study, the behavior of individual SNPs originating from diesel engines was studied under compression. The experiments were performed in a transmission electron microscope using a nanoindentation device. The nanoparticles exhibited elasto-plastic behavior in response to consecutive compression cycles. From the experimental data, the Young’s modulus and hardness of the SNPs were calculated. The Young’s modulus and hardness of the nanoparticles increased with the number of compression cycles. Using an electron energy loss spectroscopy technique, it was shown that the sp2/sp3 ratio within the compressed nanoparticle decreases, which is suggested to be the cause of the increase in elasticity and hardness. In order to corroborate the experimental findings, molecular dynamics simulations of a model SNP were performed. The SNP model was constructed using carbon and hydrogen atoms with morphology and composition comparable to those observed in the experiment. The model SNP was subjected to repeated compressions between two virtual rigid walls. During the simulation, the nanoparticle exhibited elasto-plastic behavior like that in the experiments. The results of the simulations confirm that the increase in the elastic modulus and hardness is associated with a decrease in the sp2/sp3 ratio.

  4. Titanate nanotubes sensitized with silver nanoparticles: Synthesis, characterization and in-situ pollutants photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Barrocas, B.; Nunes, C.D. [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Carvalho, M.L. [LIBPhys-UNL, Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação and Departamento de Física da Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Monteiro, O.C., E-mail: ocmonteiro@ciencias.ulisboa.pt [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2016-11-01

    Highlights: • Combination of titanate nanotubes with crystalline silver nanoparticles is described. • AgHTNT demonstrated high photocatalytic activity for hydroxyl radical production. • AgHTNT exhibits the best photocatalytic activity for phenol removal. • Recycling does not affect AgHTNT photocatalytic performance. • Silver nanoparticles growth continues during several irradiation cycles. - Abstract: In this work, titanate nanotubes were modified with silver nanoparticles to produce new nanocomposite materials with enhanced photocatalytic activity for phenol removal. The TNTs were produced using a hydrothermal approach and, after being submitted to an Ag{sup +} exchange process, metallic Ag nanoparticles were obtained over the nanotubes surface. The prepared materials were structural, morphological and optical characterized by X-ray powder diffraction, micro X-ray fluorescence, transmission electron microscopy, diffused reflectance spectroscopy and X-ray photoelectron spectroscopy. The characterization results indicate that Ag{sup +} was immobilized not only in the nanotubes external surface but mainly in the TiO{sub 6} interlayers space. The application of this new nanocomposite material on photocatalytic degradation of pollutants was investigated. First, the evaluation of hydroxyl radical formation, using the terephthalic acid as a probe was studied. The photocatalytic activity of the sensitized materials for phenol degradation was afterwards evaluated. The results show that the nanocomposite sample is the best catalyst, achieving 98.0% photodegradation efficiency of a 0.2 mM phenol solution within 20 min under UV–vis radiation. The reusability of the prepared samples as photocatalysts was evaluated in four successive degradation assays, using fresh phenol solutions. The sensitized sample demonstrated excellent catalytic reusability ability, without loss of photochemical stability. The structural and morphological characterization during these

  5. Sintering of oxide-supported Pt and Pd nanoparticles in air studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose

    of the sintering mechanisms of nanoparticles is important for making improvements to their long term catalytic activity. Diesel oxidation catalysts are usually composed of noble metal nanoparticles on a complex three-dimensional high surface area oxide. The complex support structure makes it difficult to directly...... observe dynamical processes such as particle sintering with the present state of the art microscope techniques, and consequently it is difficult to relate experimental observations and theoretical sintering models. To reduce the complexity, the present study uses planar model catalysts. These are composed...

  6. Direct Observations of Oxygen-induced Platinum Nanoparticle Ripening Studied by In Situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chorkendorff, Ib; Dahl, Søren

    2010-01-01

    mbar air at 650 degrees C. Time-resolved image series unequivocally reveal that the sintering of Pt nanoparticles was mediated by an Ostwald ripening process. A statistical analysis of an ensemble of Pt nanoparticles shows that the particle size distributions change shape from an initial Gaussian...... distribution via a log-normal distribution to a Lifshitz-Slyozov-Wagner (LSW) distribution. Furthermore, the time-dependency of the ensemble-averaged particle size and particle density is determined. A mean field kinetic description captures the main trends in the observed behavior. However, at the individual...

  7. In-situ TEM visualization of vacancy injection and chemical partition during oxidation of Ni-Cr nanoparticles.

    Science.gov (United States)

    Wang, Chong-Min; Genc, Arda; Cheng, Huikai; Pullan, Lee; Baer, Donald R; Bruemmer, Stephen M

    2014-01-14

    Oxidation of alloy often involves chemical partition and injection of vacancies. Chemical partition is the consequence of selective oxidation, while injection of vacancies is associated with the differences of diffusivity of cations and anions. It is far from clear as how the injected vacancies behave during oxidation of metal. Using in-situ transmission electron microscopy, we captured unprecedented details on the collective behavior of injected vacancies during oxidation of metal, featuring an initial multi-site oxide nucleation, vacancy supersaturation, nucleation of a single cavity, sinking of vacancies into the cavity and accelerated oxidation of the particle. High sensitive energy dispersive x-ray spectroscopy mapping reveals that Cr is preferentially oxidized even at the initial oxidation, leading to a structure that Cr oxide is sandwiched near the inner wall of the hollow particle. The work provides a general guidance on tailoring of nanostructured materials involving multi-ion exchange such as core-shell structured composite nanoparticles.

  8. MO-AB-BRA-02: Modeling Nanoparticle-Eluting Spacer Degradation During Brachytherapy Application with in Situ Dose-Painting

    Energy Technology Data Exchange (ETDEWEB)

    Boateng, F [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Ngwa, W [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Brachytherapy application with in situ dose-painting using gold nanoparticles (GNP) released from GNP-loaded brachytherapy spacers has been proposed as an innovative approach to increase therapeutic efficacy during brachytherapy. This work investigates the dosimetric impact of slow versus burst release of GNP from next generation biodegradable spacers. Methods: Mathematical models were developed based on experimental data to study the release of GNP from a spacer designed with FDA approved poly(lactic-co-glycolic acid) (PLGA) polymer. The diffusion controlled released process and PLGA polymer degradation kinetics was incorporated in the calculations for the first time. An in vivo determined diffusion coefficient was used for determining the concentration profiles and corresponding dose enhancement based on initial GNP-loading concentrations of 7 mg/g. Results: The results showed that there is significant delay before the concentration profile of GNP diffusion in the tumor is similar to that when burst release is assumed as in previous studies. For example, in the case of burst release after spacer administration, it took up to 25 days for all the GNP to be released from the spacer using diffusion controlled release process only. However, it took up to 45 days when a combined model for both diffusion and polymer degradation processes was used. Based on the tumor concentration profiles, a significant dose enhancement factor (DEF >20%), could be attained at a tumor distances of 5 mm from a spacer loaded with 10 nm GNP sizes. Conclusion: The results highlight the need to take the slow release of GNP from spacers and factors such as biodegradation of polymers into account in research development of GNP-eluting spacers for brachytherapy applications with in-situ dose-painting using gold nanoparticles. The findings suggest that I-125 may be the more appropriate for such applications given the relatively longer half-live compared to other radioisotopes like Pd-103

  9. Development of an automated method for in situ measurement of the geometrical properties of the ITER bolometer diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Meister, H., E-mail: meister@ipp.mpg.de; Penzel, F.; Giannone, L.; Kannamueller, M.; Kling, A.; Koll, J.; Trautmann, T.

    2011-10-15

    In order to derive the local emission profile of the plasma radiation in a fusion device using the line-integrated measurements of the bolometer diagnostic, tomographic reconstruction methods have to be applied to the measurements from many lines-of-sight. A successful reconstruction needs to take the finite sizes of detectors and apertures and the resulting non-ideal measurements into account. In ITER a method for in situ measurement of the geometrical properties of the various components of the bolometer diagnostic after installation is required as the viewing cones have to pass through narrow gaps between components. The method proposed to be used for ITER uses the beam of a laser with high intensity to illuminate the bolometer assembly from many different angles {xi} and {theta}. A light-weight robot from Kuka Robotics is used to efficiently position the laser on many points covering the complete viewing cone of each line-of-sight and to direct the beam precisely into the entrance aperture of the bolometer. Measuring the response of the bolometer allows for the calculation of the transmission function t({xi}, {theta}), the angular etendue and finally the geometric function in reconstruction space, which is required for the tomography algorithms. Measuring the transmission function for a laboratory assembly demonstrates the viability of the proposed method. Results for a collimator-type camera from a prototype envisaged for ITER are presented. The implemented procedure is discussed in detail, in particular with respect to the automatisation applied which takes the achievable positioning and alignment accuracies of the robot into account. This discussion is extended towards the definition of requirements for a remote-handling tool for ITER.

  10. Controlled in situ growth of tunable plasmonic self-assembled nanoparticle arrays.

    NARCIS (Netherlands)

    Verre, R.; Fleischer, K.; McGilp, J.F.; Fox, D.; Behan, G.; Zhang, H.; Shvets, I.V.

    2012-01-01

    Self-assembled silver nanoparticle (NP) arrays were produced by deposition at glancing angles on transparent stepped Al2O3 templates. The evolution of the plasmonic resonances has been monitored using reflection anisotropy spectroscopy (RAS) during growth. It is demonstrated that the morphology of

  11. Temperature-induced formation of polymeric nanoparticles: in situ SAXS and QENS experiments

    Czech Academy of Sciences Publication Activity Database

    Sedlák, M.; Falus, P.; Steinhart, Miloš; Gummel, J.; Štěpánek, Petr; Filippov, Sergey K.

    2013-01-01

    Roč. 214, č. 24 (2013), s. 2841-2847 ISSN 1022-1352 R&D Projects: GA ČR GAP108/12/0640 Institutional support: RVO:61389013 Keywords : cryo-transmission electron microscopy (cryo- TEM ) * nanoparticles * neutron-spin-echo (NSE) spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.451, year: 2013

  12. Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes

    NARCIS (Netherlands)

    Matsuhisa, N.; Inoue, D.; Zalar, P.; Jin, H.; Matsuba, Y.; Itoh, A.; Yokota, T.; Hashizume, D.; Someya, T.

    2017-01-01

    Printable elastic conductors promise large-area stretchable sensor/actuator networks for healthcare, wearables and robotics. Elastomers with metal nanoparticles are one of the best approaches to achieve high performance, but large-area utilization is limited by difficulties in their processability.

  13. Polypropylene Nano composites Obtained by In Situ Polymerization Using Metallocenes Catalyst: Influence of the Nanoparticles on the Final Polymer Morphology

    International Nuclear Information System (INIS)

    Zapata, P.; Quijada, R.

    2012-01-01

    Polypropylene nano composites containing silica nanospheres based on the sol-gel methods were produced via in situ polymerization using a rac-Et(Ind) 2 ZrCl 2 /methylaluminoxane (MAO) system. Two different routes were used depending on the interaction between the silica nanoparticles with the catalytic system. In route 1 the nanoparticles were added together with the catalytic system (rac-Et(Ind) 2 ZrCl 2 )/(MAO) directly into the reactor, and in route 2 the metallocenes rac-Et(Ind) 2 ZrCl 2 was supported on silica nanospheres pretreated with (MAO). SEM images show that when the nanospheres were added by both routes, they were replicated in the final polymer particle morphology; this phenomenon was more pronounced for PP obtained by route 2. The polypropylene (PP) nano composites obtained by both routes had a slightly higher percent crystallinity and crystallinity temperatures than pure PP. Transmission electron microscopy (TEM) images show that the nanospheres were well dispersed into the polypropylene matrix, particularly in the nano composites obtained by the support system (route 2).

  14. In situ probing of temperature in radio frequency thermal plasma using Yttrium ion emission lines during synthesis of yttria nanoparticles

    Science.gov (United States)

    Dhamale, G. D.; Tiwari, N.; Mathe, V. L.; Bhoraskar, S. V.; Ghorui, S.

    2017-07-01

    Particle feeding is used in the most important applications of radio frequency (r.f.) thermal plasmas like synthesis of nanoparticles and particle spheroidization. The study reports an in-situ investigation of radial distribution of temperature in such devices using yttrium ion emission lines under different rates of particle loading during synthesis of yttria nanoparticles. A number of interesting facts about the response of r.f. plasma to the rate of particle loading, hitherto unknown, are revealed. Observed phenomena are supported with experimental data from fast photographic experiments and actual synthesis results. The use of the Abel inversion technique together with simultaneous multi-track acquisition of emission spectra from different spatial locations using a CCD based spectrometer allowed us to extract accurate distribution of temperature inside the plasma in the presence of inherent instabilities. The temperature profiles of this type of plasma have been measured possibly for the first time while particles are being fed into the plasma. Observed changes in the temperature profiles as the particle feed rate increases are very significant. Reaction forces resulting from particle evaporation, and increased skin depth owing to the decrease in electrical conductivity in the edge region are proposed as the two different mechanisms to account for the observed changes in the temperature profile as the powder feed rate is increased. Quantitative analyses supporting the proposed mechanisms are presented.

  15. Atomic-Scale Mechanism on Nucleation and Growth of Mo2C Nanoparticles Revealed by in Situ Transmission Electron Microscopy.

    Science.gov (United States)

    Fei, Linfeng; Ng, Sheung Mei; Lu, Wei; Xu, Ming; Shu, Longlong; Zhang, Wei-Bing; Yong, Zehui; Sun, Tieyu; Lam, Chi Hang; Leung, Chi Wah; Mak, Chee Leung; Wang, Yu

    2016-12-14

    With a similar electronic structure as that of platinum, molybdenum carbide (Mo 2 C) holds significant potential as a high performance catalyst across many chemical reactions. Empirically, the precise control of particle size, shape, and surface nature during synthesis largely determines the catalytic performance of nanoparticles, giving rise to the need of clarifying the underlying growth characteristics in the nucleation and growth of Mo 2 C. However, the high-temperature annealing involved during the growth of carbides makes it difficult to directly observe and understand the nucleation and growth processes. Here, we report on the use of advanced in situ transmission electron microscopy with atomic resolution to reveal a three-stage mechanism during the growth of Mo 2 C nanoparticles over a wide temperature range: initial nucleation via a mechanism consistent with spinodal decomposition, subsequent particle coalescence and monomer attachment, and final surface faceting to well-defined particles with minimum surface energy. These microscopic observations made under a heating atmosphere offer new perspectives toward the design of carbide-based catalysts, as well as the tuning of their catalytic performances.

  16. Bipyridine based metallogels: an unprecedented difference in photochemical and chemical reduction in the in situ nanoparticle formation.

    Science.gov (United States)

    Tatikonda, Rajendhraprasad; Bertula, Kia; Nonappa; Hietala, Sami; Rissanen, Kari; Haukka, Matti

    2017-02-28

    Metal co-ordination induced supramolecular gelation of low molecular weight organic ligands is a rapidly expanding area of research due to the potential in creating hierarchically self-assembled multi-stimuli responsive materials. In this context, structurally simple O-methylpyridine derivatives of 4,4'-dihydroxy-2,2'-bipyridine ligands are reported. Upon complexation with Ag(i) ions in aqueous dimethyl sulfoxide (DMSO) solutions the ligands spontaneously form metallosupramolecular gels at concentrations as low as 0.6 w/v%. The metal ions induce the self-assembly of three dimensional (3D) fibrillar networks followed by the spontaneous in situ reduction of the Ag-centers to silver nanoparticles (AgNPs) when exposed to daylight. Significant size and morphological differences of the AgNP's was observed between the standard chemical and photochemical reduction of the metallogels. The gelation ability, the nanoparticle formation and rheological properties were found to be depend on the ligand structure, while the strength of the gels is affected by the water content of the gels.

  17. Polypropylene Nanocomposites Obtained by In Situ Polymerization Using Metallocene Catalyst: Influence of the Nanoparticles on the Final Polymer Morphology

    Directory of Open Access Journals (Sweden)

    Paula Zapata

    2012-01-01

    Full Text Available Polypropylene nanocomposites containing silica nanospheres based on the sol-gel methods were produced via in situ polymerization using a rac-Et(Ind2ZrCl2/methylaluminoxane (MAO system. Two different routes were used depending on the interaction between the silica nanoparticles with the catalytic system. In route 1 the nanoparticles were added together with the catalytic system (rac-Et(Ind2ZrCl2/(MAO directly into the reactor, and in route 2 the metallocene rac-Et(Ind2ZrCl2 was supported on silica nanospheres pretreated with (MAO. SEM images show that when the nanospheres were added by both routes, they were replicated in the final polymer particle morphology; this phenomenon was more pronounced for PP obtained by route 2. The polypropylene (PP nanocomposites obtained by both routes had a slightly higher percent crystallinities and crystallinity temperatures than pure PP. Transmission electron microscopy (TEM images show that the nanospheres were well dispersed into the polypropylene matrix, particularly in the nanocomposites obtained by the support system (route 2.

  18. In Situ Analysis of a Silver Nanoparticle-Precipitating Shewanella Biofilm by Surface Enhanced Confocal Raman Microscopy.

    Directory of Open Access Journals (Sweden)

    Gal Schkolnik

    Full Text Available Shewanella oneidensis MR-1 is an electroactive bacterium, capable of reducing extracellular insoluble electron acceptors, making it important for both nutrient cycling in nature and microbial electrochemical technologies, such as microbial fuel cells and microbial electrosynthesis. When allowed to anaerobically colonize an Ag/AgCl solid interface, S. oneidensis has precipitated silver nanoparticles (AgNp, thus providing the means for a surface enhanced confocal Raman microscopy (SECRaM investigation of its biofilm. The result is the in-situ chemical mapping of the biofilm as it developed over time, where the distribution of cytochromes, reduced and oxidized flavins, polysaccharides and phosphate in the undisturbed biofilm is monitored. Utilizing AgNp bio-produced by the bacteria colonizing the Ag/AgCl interface, we could perform SECRaM while avoiding the use of a patterned or roughened support or the introduction of noble metal salts and reducing agents. This new method will allow a spatially and temporally resolved chemical investigation not only of Shewanella biofilms at an insoluble electron acceptor, but also of other noble metal nanoparticle-precipitating bacteria in laboratory cultures or in complex microbial communities in their natural habitats.

  19. In situ electrochemical small-angle neutron scattering (eSANS) for quantitative structure and redox properties of polymer-coated nanoparticles

    Science.gov (United States)

    Prabhu, Vivek; Reipa, Vytas; Bonnesen, Peter; Rondinone, Adam; Formo, Eric

    2012-02-01

    Rapid growth in nanomaterial applications (energy, cosmetics and healthcare products) highlights limitations of available physicochemical characterization methods. An in situ electrochemical small-angle neutron scattering (eSANS) methodology was devised that enables direct measurements of nano and colloid material dispersion structure while undergoing reduction-oxidation (redox) reactions. By combining the electrochemical signal with contrast variant SANS, the structure of the polymer-nanoparticle complexes can be examined under electrochemical conditions. Specially-synthesized poly(ethyleneglycol)-stabilized zinc oxide nanoparticles were examined by eSANS showing an irreversible change in nanoparticle-complex structure during the potential cycle. We will report on the kinetics of the nanoparticle transformation as measured at BL-6 EQSANS, Spallation Neutron Source, Oak Ridge National Laboratory.

  20. Graphene oxide directed in-situ deposition of electroactive silver nanoparticles and its electrochemical sensing application for DNA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Ningning [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China); Gao, Feng, E-mail: fgao1981@mnnu.edu.cn [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China); Department of Chemistry, Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504 (Japan); He, Suyu; Zhu, Qionghua; Huang, Jiafu [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China); Tanaka, Hidekazu [Department of Chemistry, Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504 (Japan); Wang, Qingxiang, E-mail: axiang236@126.com [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China)

    2017-01-25

    The development of high-performance biosensing platform is heavily dependent on the recognition property of the sensing layer and the output intensity of the signal probe. Herein, we present a simple and highly sensitive biosensing interface for DNA detection on the basis of graphene oxide nanosheets (GONs) directed in-situ deposition of silver nanoparticles (AgNPs). The fabrication process and electrochemical properties of the biosensing interface were probed by electrochemical techniques and scanning electron microscopy. The results indicate that GONs can specifically adsorb at the single-stranded DNA probe surface, and induces the deposition of highly electroactive AgNPs. Upon hybridization with complementary oligonucleotides to generate the duplex DNA on the electrode surface, the GONs with the deposited AgNPs will be liberated from the sensing interface due to the inferior affinity of GONs and duplex DNA, resulting in the reduction of the electrochemical signal. Such a strategy combines the superior recognition of GONs toward single-stranded DNA and double-stranded DNA, and the strong electrochemical response of in-situ deposited AgNPs. Under optimal conditions, the biosensor can detect target DNA over a wide range from 10 fM to 10 nM with a detection limit of 7.6 fM. Also, the developed biosensor shows outstanding discriminating ability toward oligonucleotides with different mismatching degrees. - Highlights: • An novel DNA biosensor was constructed based on GONs with deposited AgNPs. • GONs catalyze the in-situ deposition of AgNPs on the sensing interface. • Unique π-stacking of GONs with probe DNA contributes high selectivity of the biosensor. • High electroactivity of AgNPs leads to low detection limit (7.6 fM) for target DNA.

  1. Polyelectrolyte-coated gold magnetic nanoparticles for immunoassay development: toward point of care diagnostics for syphilis screening.

    Science.gov (United States)

    Yang, Dong; Ma, Jianzhong; Zhang, Qinlu; Li, Ningning; Yang, Jiangcun; Raju, Paul Ananda; Peng, Mingli; Luo, Yanling; Hui, Wenli; Chen, Chao; Cui, Yali

    2013-07-16

    Immediate response for disease control relies on simple, inexpensive, and sensitive diagnostic tests, highly sought after for timely and accurate test of various diseases, including infectious diseases. Composite Fe3O4/Au nanoparticles have attracted considerable interest in diagnostic applications due to their unique physical and chemical properties. Here, we developed a simple coating procedure for gold magnetic nanoparticles (GMNs) with poly(acrylic acid) (PAA). PAA-coated GMNs (PGMNs) were stable and monodispersed and characterized by Fourier transform-infrared spectroscopy (FT-IR), transmission electron microscopy, UV-visible scanning spectrophotometry, thermogravimetric analysis, and Zetasizer methodologies. For diagnostic application, we established a novel lateral flow immunoassay (LFIA) strip test system where recombinant Treponema pallidum antigens (r-Tp) were conjugated with PGMNs to construct a particle probe for detection of anti-Tp antibodies. Intriguingly, the particle probes specifically identified Tp antibodies with a detection limitation as low as 1 national clinical unit/mL (NCU/mL). An ample pool of 1020 sera samples from three independent hospitals were obtained to assess our PGMNs-based LFIA strips, which exhibited substantially high values of sensitivity and specificity for all clinical tests (higher than 97%) and, therefore, proved to be a suitable approach for syphilis screening at a point-of-care test manner.

  2. In Situ 3D Imaging of Catalysis Induced Strain in Gold Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ulvestad, Andrew; Sasikumar, Kiran; Kim, Jong Woo; Harder, Ross; Maxey, Evan; Clark, Jesse N.; Narayanan, Badri; Deshmukh, Sanket A.; Ferrier, Nicola; Mulvaney, Paul; Sankaranarayanan, Subramanian K. R. S.; Shpyrko, Oleg G.

    2016-08-04

    Multielectron transfer processes are crucially important in energy and biological science but require favorable catalysts to achieve fast kinetics. Nanostructuring catalysts can dramatically improve their properties, which can be difficult to understand due to strain- and size-dependent thermodynamics, the influence of defects, and substrate-dependent activities. Here, we report three-dimensional (3D) imaging of single gold nanoparticles during catalysis of ascorbic acid decomposition using Bragg coherent diffractive imaging (BCDI). Local strains were measured in single nanoparticles and modeled using reactive molecular dynamics (RMD) simulations and finite element analysis (FEA) simulations. RMD reveals the pathway for local strain generation in the gold lattice: chemisorption of hydroxyl ions. FEA reveals that the RMD results are transferable to the nanocrystal sizes studied in the experiment. Our study probes the strain-activity connection and opens a powerful avenue for theoretical and experimental studies of nanocrystal catalysis.

  3. Transport and Development of Microemulsionand Surfactant Stabilized Iron Nanoparticles for In Situ Remediation

    Science.gov (United States)

    Hsu, Dennis

    This work describes the mobility assessments of microemulsion-stabilized iron oxide nanoparticles and anionic surfactant sodium diethyl hexyl phosphate (SDEHP)-stabilized nanoscale zero valent iron (NZVI) particles in laboratory porous media. The two formulations tested in this work achieved stable iron nanoparticle suspensions for months and prepared via a simple "one-pot" synthesis method developed by Wang et al. Both formulations were tested under field scale velocity of 5 m/day with no mechanical aid during the injection. A three-compartment model, involving colloid diffusion theory, diffusion theory and tailing was applied to describe the breakthrough curves of the studies. The obtained breakthrough curves of both formulations implied excellent transport in porous media with steady plateau C/Co at 0.8-0.9 and recovery of up to 0.95 for SDEHP stabilized NZVI. Post analysis on the retention of iron on the porous media implied ideal transport with consistent data to the breakthrough curves.

  4. In situ AFM analysis investigating disassembly of DNA nanoparticles and nano-films.

    Science.gov (United States)

    Zou, Yi; Wan, Lei; Blacklock, Jenifer; Oupicky, David; Mao, Guangzhao

    2013-01-01

    Synthetic vector-based gene delivery systems continue to gain strength as viable alternatives to viral vectors due to safety and other concerns. DNA release dynamics is key to the understanding and control of gene delivery from nano-systems. Here we describe atomic force microscope application to the understanding of DNA release dynamics from bioreducible polycation-based nano-systems. The two nano-systems are polyplex nanoparticles and layer-by-layer films.

  5. In situ x-ray imaging of nanoparticle agglomeration in fluidized beds

    International Nuclear Information System (INIS)

    Jenneson, Paul Michael; Gundogdu, Ozcan

    2006-01-01

    A high spatial (down to 400 nm) and temporal resolution (down to 1 ms) x-ray imaging apparatus has been designed to study the agglomeration of arc plasma synthesized zinc oxide nanoparticles (average diameter of 50 nm) in fluidized beds under different gas flow velocities. The mean volume distribution of the nanoparticle agglomerates was determined with x-ray microtomography and found to correspond to a lognormal distribution with a mean value of 0.70x10 9 μm 3 and a variance of 3.6x10 21 (μm 3 ) 2 . The average density of the agglomerates was found to be 2.9 g cm -3 compared to 5.6 g cm -3 for the individual nanoparticles. The powder assembly was then dynamically imaged using an x-ray image intensifier coupled to a digital camera using a field of view of 24.20 mm by 32.25 mm and a temporal resolution of 40 ms. Sequential frames were captured into computer memory for a range of gas flow velocities from 0.026 ms -1 to 0.313 ms -1 . The breakup energy of the agglomerates was calculated to be approximately 2x10 -8 J using a combination of dynamic observations and physical properties of the agglomerate system extracted from the x-ray microtomographic data

  6. Barrierless growth of precursor-free, ultrafast laser-fragmented noble metal nanoparticles by colloidal atom clusters - A kinetic in situ study.

    Science.gov (United States)

    Jendrzej, Sandra; Gökce, Bilal; Amendola, Vincenzo; Barcikowski, Stephan

    2016-02-01

    Unintended post-synthesis growth of noble metal colloids caused by excess amounts of reactants or highly reactive atom clusters represents a fundamental problem in colloidal chemistry, affecting product stability or purity. Hence, quantified kinetics could allow defining nanoparticle size determination in dependence of the time. Here, we investigate in situ the growth kinetics of ps pulsed laser-fragmented platinum nanoparticles in presence of naked atom clusters in water without any influence of reducing agents or surfactants. The nanoparticle growth is investigated for platinum covering a time scale of minutes to 50days after nanoparticle generation, it is also supplemented by results obtained from gold and palladium. Since a minimum atom cluster concentration is exceeded, a significant growth is determined by time resolved UV/Vis spectroscopy, analytical disc centrifugation, zeta potential measurement and transmission electron microscopy. We suggest a decrease of atom cluster concentration over time, since nanoparticles grow at the expense of atom clusters. The growth mechanism during early phase (<1day) of laser-synthesized colloid is kinetically modeled by rapid barrierless coalescence. The prolonged slow nanoparticle growth is kinetically modeled by a combination of coalescence and Lifshitz-Slyozov-Wagner kinetic for Ostwald ripening, validated experimentally by the temperature dependence of Pt nanoparticle size and growth quenching by Iodide anions. Copyright © 2015. Published by Elsevier Inc.

  7. Double-staining chromogenic in situ hybridization as a useful alternative to split-signal fluorescence in situ hybridization in lymphoma diagnostics

    DEFF Research Database (Denmark)

    van Rijk, A.; Svenstroup-Poulsen, T.; Jones, M.

    2010-01-01

    , their detection is an important adjunct for increasing the reliability of the diagnosis. Recently, split-signal fluorescence hi situ hybridization has become available as a robust method to detect chromosomal breaks in paraffin-embedded formalin-fixed tissues. A bright field approach would bring this technology...... within the reach of every pathology laboratory. Design and Methods Our study was initiated to determine the consistency between chromogenic in situ hybridization and fluorescence in situ hybridization, both using split-signal probes developed for the detection of chromosomal breaks. Five hundred...... and forty cases of I I lymphoma entities and reactive, benign lymphoid tissues, collected from eight different pathology laboratories, placed on 1.5 fluorescence in situ hybridization pre-stained tissue microarray slides, were double stained for the chromogenic hybridization. For each core morphology...

  8. In situ UV-vis investigation of growth of gold nanoparticles prepared by solution plasma sputtering in NaCl solution

    Science.gov (United States)

    Mizutani, Tsuyoshi; Ogawa, Satoshi; Murai, Takaaki; Nameki, Hirofumi; Yoshida, Tomoko; Yagi, Shinya

    2015-11-01

    Gold nanoparticles are prepared in various concentrations of NaCl solutions by solution plasma sputtering. The absorption spectra of these solutions during and after the plasma process are measured by in situ ultraviolet-visible (UV-vis) spectroscopy to estimate the particle diameters and concentrations of gold. The distributions of particle diameters are obtained by transmission electron microscope (TEM) observations. These experiments indicate the gold nanoparticles with about 2.2 nm are directly formed by plasma phase and the diameters are increasing over time. These increases of particle diameters are caused by Ostwald ripening of gold nanoparticles in NaCl solution. We estimate the equilibrium diameter at which the gold nanoparticles are not solved in NaCl solution using in situ UV-vis spectroscopy. These diameters are about 5, 7 and 10 nm in 3, 5 and 10 mM NaCl solution, respectively. We make it possible to control the diameter of gold nanoparticles prepared by solution plasma sputtering in NaCl solution.

  9. Rapid detection of chromosome rearrangement in medical diagnostic X-ray workers by using fluorescence in situ hybridization and study on dose estimation

    International Nuclear Information System (INIS)

    Wang Zhiquan; Sun Yuanming; Li Jin

    1998-01-01

    Objective: Biological doses were estimated for medical diagnostic X-ray workers. Methods: Chromosome rearrangements in X-ray workers were analysed by fluorescence in situ hybridization (FISH) with composite whole chromosome paintings number 4 and number 7. Results: The frequency of translocation in medical diagnostic X-ray workers was much higher than that in control group (P<0.01). The biological doses to individual X-ray workers were calculated by their translocation frequency. The translocation frequencies of both FISH and G-banding were in good agreement. Conclusion: The biological doses to X-ray workers are estimated by FISH first when their dosimetry records are not documented

  10. Fluorescence in situ hybridization and immunohistochemistry as diagnostic methods for ALK positive non-small cell lung cancer patients.

    Directory of Open Access Journals (Sweden)

    Pablo Martinez

    Full Text Available BACKGROUND: Anaplastic Lymphoma Kinase (ALK positivity represents a novel molecular target in a subset of Non-Small Cell Lung Cancers (NSCLC. We explore Fluorescence in situ Hybridization (FISH and Immunohistochemistry (IHC as diagnostic methods for ALK positive patients and to describe its prevalence and outcomes in a population of NSCLC patients. METHODS: NSCLC patients previously screened for Epidermal Growth Factor Receptor (EGFR at our institution were selected. ALK positive patients were identified by FISH and the value of IHC (D5F3 was explored. RESULTS: ninety-nine patients were identified. Median age was 61.5 years (range 35-83, all were caucasians, eighty percent were adenocarcinomas, fifty-one percent were male and thirty-eight percent were current smokers. Seven (7.1% patients were ALK positive by FISH, thirteen (13.1% were EGFR mutant, and 65 (65.6% were negative/Wild Type (WT for both ALK and EGFR. ALK positivity and EGFR mutations were mutually exclusive. ALK positive patients tend to be younger than EGFR mutated or wt patients. ALK positive patients were predominantly never smokers (71.4% and adenocarcinoma (71.4%. ALK positive and EGFR mutant patients have a better outcome than negative/WT. All patients with ALK FISH negative tumours were negative for ALK IHC. Out of 6 patients positive for ALK FISH with more tissue available, 5 were positive for ALK IHC and 1 negative. CONCLUSIONS: ALK positive patients represent 7.1% of a population of selected NSCLC. ALK positive patients have different clinical features and a better outcome than EGFR WT and ALK negative patients. IHC is a promising method for detecting ALK positive NSCLC patients.

  11. Fluorescence In Situ Hybridization and Immunohistochemistry as Diagnostic Methods for ALK Positive Non-Small Cell Lung Cancer Patients

    Science.gov (United States)

    Martinez, Pablo; Hernández-Losa, Javier; Cedrés, Susana; Castellví, Josep; Martinez-Marti, Alex; Tallada, Natalia; Murtra-Garrell, Nuria; Navarro-Mendivill, Alejandro; Rodriguez-Freixinos, Victor; Canela, Mercedes; Ramon y Cajal, Santiago; Felip, Enriqueta

    2013-01-01

    Background Anaplastic Lymphoma Kinase (ALK) positivity represents a novel molecular target in a subset of Non-Small Cell Lung Cancers (NSCLC). We explore Fluorescence in situ Hybridization (FISH) and Immunohistochemistry (IHC) as diagnostic methods for ALK positive patients and to describe its prevalence and outcomes in a population of NSCLC patients. Methods NSCLC patients previously screened for Epidermal Growth Factor Receptor (EGFR) at our institution were selected. ALK positive patients were identified by FISH and the value of IHC (D5F3) was explored. Results ninety-nine patients were identified. Median age was 61.5 years (range 35–83), all were caucasians, eighty percent were adenocarcinomas, fifty-one percent were male and thirty-eight percent were current smokers. Seven (7.1%) patients were ALK positive by FISH, thirteen (13.1%) were EGFR mutant, and 65 (65.6%) were negative/Wild Type (WT) for both ALK and EGFR. ALK positivity and EGFR mutations were mutually exclusive. ALK positive patients tend to be younger than EGFR mutated or wt patients. ALK positive patients were predominantly never smokers (71.4%) and adenocarcinoma (71.4%). ALK positive and EGFR mutant patients have a better outcome than negative/WT. All patients with ALK FISH negative tumours were negative for ALK IHC. Out of 6 patients positive for ALK FISH with more tissue available, 5 were positive for ALK IHC and 1 negative. Conclusions ALK positive patients represent 7.1% of a population of selected NSCLC. ALK positive patients have different clinical features and a better outcome than EGFR WT and ALK negative patients. IHC is a promising method for detecting ALK positive NSCLC patients. PMID:23359795

  12. Construction of Au@Pt core—satellite nanoparticles based on in-situ reduction of polymeric ionic liquid protected gold nanoparticles

    Science.gov (United States)

    Wu, Wenlan; Li, Junbo; Zou, Sheng; Guo, Jinwu; Zhou, Huiyun

    2017-03-01

    A method of in-situ reduction to prepare Au@Pt core-satellite nanoparticles (NPs) is described by using Au NPs coating poly[1-methyl 3-(2-methacryloyloxy propylimidazolium bromine)] (PMMPImB-@-Au NPs) as the template. After electrostatic complex chloroplatinic acid with PMMPImB shell, the composite NP was directly reduced with N2H4 to produce Au@Pt core-satellite NPs. The characterization of composite and core-satellite NPs under different amounts of chloroplatinic acid were studied by DLS, UV-vis absorption spectrum and TEM. The satellite Pt NPs with a small size ( 2 nm) dotted around Au core, and the resulting Au@Pt core-satellite NPs showed a red-shift surface plasmon resonance (SPR) and a good dispersion due to effectively electrostatic repulsion providing by the polymeric ionic liquid (PIL) shell. Finally, Au@Pt core-satellite NPs exhibit an enhanced catalytic activity and cycled catalytic capability for the reduction of p-nitrophenol with NaBH4.

  13. Antibacterial continuous nanofibrous hybrid yarn through in situ synthesis of silver nanoparticles: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Barani, Hossein, E-mail: barani@birjand.ac.ir

    2014-10-01

    Nanofibrous hybrid yarns of polyvinyl alcohol (PVA) and poly-L-lactide acid (PLLA) with the antibacterial activity were prepared that contains 0, 5, 10, 20, and 30 wt.% of silver nanoparticles according to the PVA polymer content. This was performed by electrospinning using distilled water and 2, 2, 2-trifluoroethanol as a solvent for PVA and PLLA respectively, and sodium borohydride was used as a reducing agent. The scanning electron microscope observation confirmed the formation of AgNPs into the PVA nanofiber structure, and they were uniform, bead free, cylindrical and smooth. The diameter of hybrid yarns and their nanofiber component was decreased as the silver nitrate concentration in electrospinning solutions was increased. The differential scanning calorimetry results indicated that the silver nanoparticles can form interactions with polymer chains and decrease the melting enthalpy. The mechanical analysis showed a lower stress and strain at break of the AgNP-loaded nanofibrous hybrid yarns than the unloaded hybrid yarn. However, there wasn't a statistically significant difference between the strain at break of electrospun nanofibrous hybrid yarns. Moreover, the bactericidal efficiency of all loaded samples was over 99.99%. - Highlights: • Nanofibrous hybrid yarns of PVA/PLLA with antibacterial activity were prepared. • The diameter of nanofibers was decreased as the AgNP concentration was increased. • AgNPs make interactions with amorphous phase of polymer and increase the Tg. • All loaded samples presented a good bactericidal and bacteriostatic efficiency.

  14. In situ imaging of ultra-fast loss of nanostructure in nanoparticle aggregates

    International Nuclear Information System (INIS)

    Egan, Garth C.; Sullivan, Kyle T.; LaGrange, Thomas; Reed, Bryan W.; Zachariah, Michael R.

    2014-01-01

    The word “nanoparticle” nominally elicits a vision of an isolated sphere; however, the vast bulk of nanoparticulate material exists in an aggregated state. This can have significant implications for applications such as combustion, catalysis, and optical excitation, where particles are exposed to high temperature and rapid heating conditions. In such environments, particles become susceptible to morphological changes which can reduce surface area, often to the detriment of functionality. Here, we report on thermally-induced coalescence which can occur in aluminum nanoparticle aggregates subjected to rapid heating (10 6 –10 11  K/s). Using dynamic transmission electron microscopy, we observed morphological changes in nanoparticle aggregates occurring in as little as a few nanoseconds after the onset of heating. The time-resolved probes reveal that the morphological changes initiate within 15 ns and are completed in less than 50 ns. The morphological changes were found to have a threshold temperature of about 1300 ± 50 K, as determined by millisecond-scale experiments with a calibrated heating stage. The temperature distribution of aggregates during laser heating was modeled with various simulation approaches. The results indicate that, under rapid heating conditions, coalescence occurs at an intermediate temperature between the melting points of aluminum and the aluminum oxide shell, and proceeds rapidly once this threshold temperature is reached

  15. In situ imaging of ultra-fast loss of nanostructure in nanoparticle aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Egan, Garth C. [Department of Materials Science, University of Maryland, College Park, Maryland 20742 (United States); Sullivan, Kyle T.; LaGrange, Thomas; Reed, Bryan W. [Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Zachariah, Michael R., E-mail: mrz@umd.edu [Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States); Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 (United States)

    2014-02-28

    The word “nanoparticle” nominally elicits a vision of an isolated sphere; however, the vast bulk of nanoparticulate material exists in an aggregated state. This can have significant implications for applications such as combustion, catalysis, and optical excitation, where particles are exposed to high temperature and rapid heating conditions. In such environments, particles become susceptible to morphological changes which can reduce surface area, often to the detriment of functionality. Here, we report on thermally-induced coalescence which can occur in aluminum nanoparticle aggregates subjected to rapid heating (10{sup 6}–10{sup 11} K/s). Using dynamic transmission electron microscopy, we observed morphological changes in nanoparticle aggregates occurring in as little as a few nanoseconds after the onset of heating. The time-resolved probes reveal that the morphological changes initiate within 15 ns and are completed in less than 50 ns. The morphological changes were found to have a threshold temperature of about 1300 ± 50 K, as determined by millisecond-scale experiments with a calibrated heating stage. The temperature distribution of aggregates during laser heating was modeled with various simulation approaches. The results indicate that, under rapid heating conditions, coalescence occurs at an intermediate temperature between the melting points of aluminum and the aluminum oxide shell, and proceeds rapidly once this threshold temperature is reached.

  16. In-Situ Synchrotron Radiation Study of Formation and Growth of Crystalline CexZr1-xO2 Nanoparticles Synthesized in Supercritical Water

    DEFF Research Database (Denmark)

    Tyrsted, Christoffer; Becker-Christensen, Jacob; Hald, Peter

    2010-01-01

    -zirconia system, the growth of ceria and zirconia nanoparticles is fundamentally different under supercritical water conditions. For comparison, ex situ synthesis has also been performed using an in-house supercritical flow reactor. The resulting samples were analyzed using PXRD, small-angle X-ray scattering......In situ synchrotron powder X-ray diffraction (PXRD) measurements have been conducted to follow the nucleation and growth of crystalline CexZr1-xO2 nanoparticles synthesized in supercritical water with a full substitution variation (x = 0, 0.2, 0.5, 0.8, and 1.0). Direction-dependent growth curves...... are determined and described using reaction kinetic models. A distinct change in growth kinetics is observed with increasing cerium content. For x = 0.8 and 1.0 (high cerium content), the growth is initially limited by the surface reaction kinetics; however, at a size of ∼6 nm, the growth changes and becomes...

  17. Direct in situ activation of Ag0 nanoparticles in synthesis of Ag/TiO2 and its photoactivity

    International Nuclear Information System (INIS)

    Jaafar, N.F.; Jalil, A.A.; Triwahyono, S.; Efendi, J.; Mukti, R.R.; Jusoh, R.; Jusoh, N.W.C.; Karim, A.H.; Salleh, N.F.M.; Suendo, V.

    2015-01-01

    Graphical abstract: - Highlights: • Ag 0 loaded on TiO 2 was prepared by a direct in situ electrochemical method. • 5 wt% Ag–TiO 2 demonstrated the best photocatalytic degradation of 2-CP. • Isomorphous substitution of Ag with Ti occurred to form Ti−O−Ag bonds. • Ag 0 and oxygen vacancies trapped electrons to enhance e–H + separation. • Substitution of Ag in the TiO 2 structure decreased the number of oxygen vacancies. - Abstract: Metallic Ag nanoparticles (Ag 0 ) were successfully activated using a direct in situ electrochemical method before being supported on TiO 2 . Catalytic testing showed that 5 wt% Ag–TiO 2 gave the highest photodegradation (94%) of 50 mg L −1 2-chlorophenol (2-CP) at pH 5 using 0.375 g L −1 catalyst within 6 h, while under similar conditions, 1 wt% and 10 wt% Ag–TiO 2 only gave 75% and 78% degradation, respectively. Characterization results illustrated that the photoactivity was affected by the amount of Ag 0 and oxygen vacancies which act as an electrons trap to enhance the electron–hole separation. While, the Ag−O−Ti bonds formation reduced the photoactivity. The degradation followed a pseudo-first order Langmuir–Hinshelwood model where adsorption was the controlling step. Study on the effect of scavengers showed that the hole (H + ) and hydroxyl radical (OH·) play important roles in the photodegradation. The regenerated photocatalyst was still stable after five cycling runs

  18. Cellulose nanocomposite films with in situ generated silver nanoparticles using Cassia alata leaf extract as a reducing agent.

    Science.gov (United States)

    Sivaranjana, P; Nagarajan, E R; Rajini, N; Jawaid, M; Rajulu, A Varada

    2017-06-01

    Cotton linters were dissolved in aq. (8% LiOH+15% urea) that was pre-cooled to -12.5°C. Using this solution cellulose gel films were prepared by regeneration method with ethyl alcohol as a coagulant. These wet films were diffused with 10wt% Cassia alata leaf extract that acted as a reducing agent. The leaf extract diffused cellulose wet films were used as the matrix. The wet matrix films were dipped individually in lower concentrated 1-5mM aq.AgNO 3 source solutions in the presence of sunlight and allowed the solutions to react with the diffused leaf extract reducing agent which in situ generated the silver nanoparticles (AgNPs) inside the films as well as in the source solution. The AgNPs formed in the source solution were observed by transmission electron microscope (TEM) and scanning electron microscope (SEM) while those formed in situ the films were observed by SEM and the particle size distribution was determined. The cellulose/AgNP composite films showed good antibacterial activity against Escherichia coli bacteria. These nanocomposite films were also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and tensile tests. At temperatures below 300°C, the thermal stability of the nanocomposite films was lower than that of the matrix due to the catalytic effect of AgNPs. The nanocomposite films also possessed good tensile properties. The ecofriendly cellulose/AgNP composite films with good antibacterial activity and tensile properties can be considered for medical applications like dressing materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. In-situ one-step synthesis of carbon-encapsulated naked magnetic metal nanoparticles conducted without additional reductants and agents

    OpenAIRE

    Kang, Jun; Kim, Yeonwon; Kim, Hye-min; Hu, Xiulan; Saito, Nagahiro; Choi, Jae-Hyuk; Lee, Myeong-Hoon

    2016-01-01

    C-encapsulated highly pure Ni, Co, and Fe magnetic nanoparticles (MNPs/C) were synthesized by an innovative one-step in-situ plasma in liquid method (solution plasma processing, SPP) without any additional reductants, agents, or treatment. Successful encapsulation of MNPs was demonstrated by using inductively coupled plasma-atomic emission spectrometry and cyclic voltammetry techniques. The obtained X-ray diffraction patterns and transmission electron microscopy images corresponded to MNPs wi...

  20. In situ prepared PET nanocomposites: Effect of organically modified montmorillonite and fumed silica nanoparticles on PET physical properties and thermal degradation kinetics

    International Nuclear Information System (INIS)

    Vassiliou, A.A.; Chrissafis, K.; Bikiaris, D.N.

    2010-01-01

    In the present study a series of PET nanocomposites were prepared by in situ polymerization using different amounts of organically modified montmorillonite (OMMT) with a triphenylphosphine compound and fumed silica nanoparticles (SiO 2 ). As verified by TEM micrographs, the dispersion of both nanoparticles into the PET matrix was homogeneous while montmorillonite was dispersed in the exfoliated form. The intrinsic viscosities of the prepared nanocomposites were affected by the addition of the nanoparticles and in both cases a slight increase was observed. Tensile strength was also increased by increasing nanoparticles content while both types of nanoparticles act as nucleating agents, enhancing the crystallization rates of PET. From the thermogravimetric curves it was concluded that PET and the samples with different nanoparticles presented good thermostability, since no remarkable mass loss occurred up to 320 o C ( 2 2 wt.% nanocomposites was almost identical (222.1 kJ/mol). However, PET/OMMT 2 wt.% nanocomposites exhibited a higher activation energy (228.3 kJ/mol), indicating that OMMT incurred a stabilizing effect upon the decomposition of the matrix. The form of the conversion function for all the studied samples obtained by fitting was the mechanism of n th -order auto-catalysis.

  1. A novel metal-to-metal bonding process through in-situ formation of Ag nanoparticles using Ag2O microparticles

    International Nuclear Information System (INIS)

    Hirose, Akio; Tatsumi, Hiroaki; Takeda, Naoya; Akada, Yusuke; Ogura, Tomo; Ide, Eiichi; Morita, Toshiaki

    2009-01-01

    The metal-to-metal bonding has been successfully achieved via the bonding process using Ag metallo-organic nanoparticles at a bonding temperature of around 300-, which can be alternative to the current microsoldering in electronics assembly using high-temperature solders. However, further reduction of bonding temperature and/or bonding pressure is needed. In the present research, a novel bonding process through in-situ formation of Ag nanoparticles instead of the filler material of the Ag metallo-organic nanoparticles has been developed. The Ag nanoparticles can form by the reduction of Ag 2 O particles. In this study, the Ag 2 O particles were mixed with triethylene glycol as a reducing agent to form a paste for bonding. The Au coated cylindrical specimens were bonded using the paste. The Ag nanoparticles formed at around 130 to 160 through the reduction process of Ag2O particles with triethylene glycol. The Ag nanoparticles were immediately sintered each other due to a great surface energy per volume. A transmission electron microscope observation revealed that the sintered Ag metallurgically bonded to the Au substrate at around 160 and a dense Ag layer formed after further heating. The tensile strength of the joint bonded at 250 under a bonding pressure of 5MPa was around 60MPa

  2. Poly-thiosemicarbazide Membrane for Gold Adsorption and In-situ Growth of Gold Nanoparticles

    KAUST Repository

    Parra, Luis F.

    2012-12-01

    In this work the synergy between a polymer containing chelate sites and gold ions was explored by the fabrication of a polymeric membrane with embedded gold nanoparticles inside its matrix and by developing a process to recover gold from acidic solutions. After realizing that the thiosemicarbazide groups present in the monomeric unit of poly-thiosemicarbazide (PTSC) formed strong complexes with Au ions, membrane technology was used to exploit this property to its maximum. The incorporation of metal nanoparticles into polymeric matrices with current technologies involves either expensive and complicated procedures or leads to poor results in terms of agglomeration, loading, dispersion, stability or efficient use of raw materials. The fabrication procedure described in this thesis solves these problems by fabricating a PTSC membrane containing 33.5 wt% in the form of 2.9 nm gold nanoparticles (AuNPs) by a three step simple and scalable procedure. It showed outstanding results in all of the areas mentioned above and demonstrated catalytic activity for the reduction of 4-Nitrophenol (4−NP) to 4-Aminophenol (4−AP). The current exponential demand of gold for electronics has encouraged the development of efficient processes to recycle it. Several adsorbents used to recover gold from acidic solutions can be found in the literature with outstanding maximum uptakes,yet, poor kinetics leading to an overall inefficient process. The method developed in this dissertation consisted in permeating the gold-containing solution through a PTSC membrane that will capture all the Au ions by forming a metal complex with them. Forcing the ions through the pores of the membrane eliminates the diffusion limitations and the adsorption will only depended on the fast complexation kinetics, resulting in a very efficient process. A flux as high as 1868 L/h m2 was enough to capture >90% of the precious metal present in a solution of 100 ppm Au. The maximum uptake achieved without sacrificing

  3. High pressure in-situ X-ray diffraction study on Zn-doped magnetite nanoparticles

    Science.gov (United States)

    Ferrari, S.; Bilovol, V.; Pampillo, L. G.; Grinblat, F.; Errandonea, D.

    2018-03-01

    We have performed high pressure synchrotron X-ray powder diffraction experiments on two different samples of Zn-doped magnetite nanoparticles (formula Fe(3-x)ZnxO4; x = 0.2, 0.5). The structural behavior of then a noparticles was studied up to 13.5 GPa for x = 0.2, and up to 17.4 GPa for x = 0.5. We have found that both systems remain in the cubic spinel structure as expected for this range of applied pressures. The analysis of the unit cell volume vs. pressure results in bulk modulus values lower than in both end-members, magnetite (Fe3O4) and zinc ferrite (ZnFe2O4), suggesting that chemical disorder may favor compressibility, which is expected to improve the increase of the Neel temperature under compression.

  4. In Situ Chemical Synthesis of Fe3O4 Nanoparticles on Reduced Graphene Oxide Sheets in Polyol Medium and Magnetic Properties.

    Science.gov (United States)

    Lee, Jeong Woo; Kim, Jong-Duk

    2015-01-01

    This letter reports the one-pot synthesis of reduced graphene oxide/Fe3O4 composites. By the electrostatic interaction of exfoliated graphene oxide and Fe3+ ions, graphene oxide/Fe3+ ions were prepared in a diethylene glycol. In situ formation of Fe3O4 nanoparticles on graphene oxide sheets and reduction of graphene oxide were then achieved simultaneously by the thermal decomposition reaction of Fe(acac)3 at high temperature. This synthetic method enables control over the phase of Fe3O4 nanoparticles on graphene sheets, further preventing restacking of the graphene sheets and aggregation of Fe3O4 nanoparticles. By controlling the mass ratio of Fe(acac)3 and graphene oxide, a series of reduced graphene oxide/Fe3O4 composites were prepared. Magnetic properties of the reduced graphene oxide/Fe3O4 composites are investigated.

  5. Synthesis of 1 nm Pd Nanoparticles in a Microfluidic Reactor: Insights from in Situ X ray Absorption Fine Structure Spectroscopy and Small-Angle X ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Ayman M.; Al Hasan, Naila M.; Ivanov, Sergei A.; Siefert, Soenke; Kelly, Ryan T.; Hallfors, Nicholas G.; Benavidez, Angelica D.; Kovarik, Libor; Jenkins, Aaron; Winans, R. E.; Datye, Abhaya K.

    2015-06-11

    In this paper we show that the temporal separation of nucleation and growth is not a necessary condition for the colloidal synthesis of monodisperse nanoparticles. The synthesis mechanism of Pd nanoparticles was determined by in situ XAFS and SAXS in a microfluidic reactor capable of millisecond up to an hour time resolution. The SAXS results showed two autocatalytic growth phases, a fast growth phase followed by a very slow growth phase. The steady increase in the number of particles throughout the two growth phases indicates the synthesis is limited by slow continuous nucleation. The transition from fast to slow growth was caused by rapid increase in bonding with the capping agent as shown by XAFS. Based on this fundamental understanding of the synthesis mechanism, we show that 1 nm monodisperse Pd nanoparticles can be synthesized at low temperature using a strong binding capping agent such as trioctylphosphine (TOP).

  6. Polymer Nanocomposite Film with Metal Rich Surface Prepared by In Situ Single-Step Formation of Palladium Nanoparticles: An Interesting Way to Combine Specific Functional Properties

    Directory of Open Access Journals (Sweden)

    David Thompson

    2016-10-01

    Full Text Available This paper presents a continuous single-step route that permits preparation of a thermostable polymer/metal nanocomposite film and to combine different functional properties in a unique material. More precisely, palladium nanoparticles are in situ generated in a polyimide matrix thanks to a designed curing cycle which is applied to a polyamic acid/metal precursor solution cast on a glass plate. A metal-rich surface layer which is strongly bonded to the bulk film is formed in addition to homogeneously dispersed metal nanoparticles. This specific morphology leads to obtaining an optically reflective film. The metal nanoparticles act as gas diffusion barriers for helium, oxygen, and carbon dioxide; they induce a tortuosity effect which allows dividing the gas permeation coefficients by a factor near to 2 with respect to the neat polyimide matrix. Moreover, the ability of the in situ synthesized palladium nanoparticles to entrap hydrogen is evidenced. The nanocomposite film properties can be modulated as a function of the location of the film metal-rich surface with respect to the hydrogen feed. The synthesized nanocomposite could represent a major interest for a wide variety of applications, from specific coatings for aerospace or automotive industry, to catalysis applications or sensors.

  7. A surface plasmon resonance sensing method for determining captopril based on in situ formation of silver nanoparticles using ascorbic acid

    Science.gov (United States)

    Rastegarzadeh, Saadat; Hashemi, Fatemeh

    2014-03-01

    A new method has been proposed to sensitive detection of captopril based on surface plasmon resonance band of silver nanoparticles (AgNPs). The stable and well-dispersed AgNPs with strong plasmon resonance signal were synthesized in situ using a simple and rapid procedure by applying ascorbic acid as reducer and sodium dodecyl sulfate as stabilizer, at room temperature. It was found that, the decreasing of AgNPs plasmon absorbance is proportional to the concentration of captopril which allows the spectrophotometric sensing of this compound. The presented method is capable of determining captopril over a range of 0.20-2.75 μmol L-1 with a limit of detection 0.07 μmol L-1. The relative standard deviation for eight replicate measurements of 1.00 and 2.50 μmol L-1 of captopril was 2.37% and 1.02%, respectively. The method was applied to the determination of captopril in pharmaceutical formulations with satisfactory results, which were in agreement with those of the official method.

  8. A surface plasmon resonance sensing method for determining captopril based on in situ formation of silver nanoparticles using ascorbic acid.

    Science.gov (United States)

    Rastegarzadeh, Saadat; Hashemi, Fatemeh

    2014-03-25

    A new method has been proposed to sensitive detection of captopril based on surface plasmon resonance band of silver nanoparticles (AgNPs). The stable and well-dispersed AgNPs with strong plasmon resonance signal were synthesized in situ using a simple and rapid procedure by applying ascorbic acid as reducer and sodium dodecyl sulfate as stabilizer, at room temperature. It was found that, the decreasing of AgNPs plasmon absorbance is proportional to the concentration of captopril which allows the spectrophotometric sensing of this compound. The presented method is capable of determining captopril over a range of 0.20-2.75 μmol L(-1) with a limit of detection 0.07 μmol L(-1). The relative standard deviation for eight replicate measurements of 1.00 and 2.50 μmol L(-1) of captopril was 2.37% and 1.02%, respectively. The method was applied to the determination of captopril in pharmaceutical formulations with satisfactory results, which were in agreement with those of the official method. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. In situ self-assembly of gold nanoparticles on hydrophilic and hydrophobic substrates for influenza virus-sensing platform

    Science.gov (United States)

    Ahmed, Syed Rahin; Kim, Jeonghyo; Tran, Van Tan; Suzuki, Tetsuro; Neethirajan, Suresh; Lee, Jaebeom; Park, Enoch Y.

    2017-03-01

    Nanomaterials without chemical linkers or physical interactions that reside on a two-dimensional surface are attractive because of their electronic, optical and catalytic properties. An in situ method has been developed to fabricate gold nanoparticle (Au NP) films on different substrates, regardless of whether they are hydrophilic or hydrophobic surfaces, including glass, 96-well polystyrene plates, and polydimethylsiloxane (PDMS). A mixture of sodium formate (HCOONa) and chloroauric acid (HAuCl4) solution was used to prepare Au NP films at room temperature. An experimental study of the mechanism revealed that film formation is dependent on surface wettability and inter particle attraction. The as-fabricated Au NP films were further applied to the colorimetric detection of influenza virus. The response to the commercial target, New Caledonia/H1N1/1999 influenza virus, was linear in the range from 10 pg/ml to 10 μg/ml and limit of detection was 50.5 pg/ml. In the presence of clinically isolated influenza A virus (H3N2), the optical density of developed color was dependent on the virus concentration (10-50,000 PFU/ml). The limit of detection of this study was 24.3 PFU/ml, a limit 116 times lower than that of conventional ELISA (2824.3 PFU/ml). The sensitivity was also 500 times greater than that of commercial immunochromatography kits.

  10. Colorimetric method for the detection of melamine using in-situ formed silver nanoparticles via tannic acid

    Science.gov (United States)

    Alam, Md. Fazle; Laskar, Amaj Ahmed; Ahmed, Shahbaz; Shaida, Mohd. Azfar; Younus, Hina

    2017-08-01

    Melamine toxicity has recently attracted worldwide attention as it causes renal failure and the death of humans and animals. Therefore, developing a simple, fast and sensitive method for the routine detection of melamine is the need of the hour. Herein, we have developed a selective colorimetric method for the detection of melamine in milk samples based upon in-situ formation of silver nanoparticles (AgNPs) via tannic acid. The AgNPs thus formed were characterized by UV-Visible spectrophotometer, transmission electron microscope (TEM), zetasizer and dynamic light scattering (DLS). The AgNPs were used to detect melamine under in vitro condition and in raw milk spiked with melamine. Under optimal conditions, melamine could be selectively detected in vitro within the concentration range of 0.05-1.4 μM with a limit of detection (LOD) of 0.01 μM, which is lower than the strictest melamine safety requirement of 1 ppm. In spiked raw milk, the recovery percentage range was 99.5-106.5% for liquid milk and 98.5-105.5% for powdered milk. The present method shows extreme selectivity with no significant interference with other substances like urea, glucose, glycine, ascorbic acid etc. This assay method does not utilize organic cosolvents, enzymatic reactions, light sensitive dye molecules and sophisticated instrumentation, thereby overcoming some of the limitations of the other conventional methods.

  11. In situ Immobilization of Copper Nanoparticles on Polydopamine Coated Graphene Oxide for H2O2 Determination.

    Directory of Open Access Journals (Sweden)

    Yingzhu Liu

    Full Text Available Nanostructured electrochemical sensors often suffer from irreversible aggregation and poor adhesion to the supporting materials, resulting in reduced sensitivity and selectivity over time. We describe a versatile method for fabrication of a H2O2 sensor by immobilizing copper nanoparticles (Cu NPs; 20 nm on graphene oxide (GO sheets via in-situ reduction of copper(II on a polydopamine (PDA coating on a glassy carbon electrode. The PDA film with its amino groups and catechol groups acts as both a reductant and an adhesive that warrants tight bonding between the Cu NPs and the support. The modified electrode, best operated at a working voltage of -0.4 V (vs. Ag/AgCl, has a linear response to H2O2 in the 5 μM to 12 mM concentration range, a sensitivity of 141.54 μA∙mM‾1∙cm‾2, a response time of 4 s, and a 1.4 μM detection limit (at an S/N ratio of 3. The sensor is highly reproducible and selective (with minimal interference to ascorbic acid and uric acid. The method was applied to the determination of H2O2 in sterilant by the standard addition method and gave recoveries between 97% and 99%.

  12. Towards multifunctional cellulosic fabric: UV photo-reduction and in-situ synthesis of silver nanoparticles into cellulose fabrics.

    Science.gov (United States)

    Rehan, Mohamed; Barhoum, Ahmed; Van Assche, Guy; Dufresne, Alain; Gätjen, Linda; Wilken, Ralph

    2017-05-01

    Herein, the highly multifunctional cotton fabric surfaces were designed with excellent coloration, UV-protection function, and antimicrobial activity. These multifunctional functions were developed by in-situ synthesis of silver nanoparticles (Ag NPs) into the cotton fabric surface using a simple green one-pot "UV-reduction" method. Cotton fabrics were pretreated with non-anionic detergent, immersed into alcoholic silver nitrate solution (concentration ranging from 100 to 500ppm), squeezed to remove excess solution and then exposed to UV-irradiation (range 320-400nm) for 1h. The influence UV-irradiation on the thermal, chemical, optical and biological properties of the cotton fabric surface was discussed in details. The UV-irradiation promotes reducing of Ag + ions and the cotton fabrics act as seed medium for Ag NPs formation by "heterogeneous nucleation". Increasing Ag + concentration (from 100 to 500ppm) results in Ag NPs of particle size (distribution) of 50-100nm. Interestingly, the Ag NPs exhibited different localized surface Plasmon resonance properties causing a coloration of the cotton fabrics with different color shades ranging from bright to dark brown with excellent color fastness properties. The treated cotton fabrics also show high protecting functions against UV-transmission (reduction of 65%) and Escherichia coli growth (99%). The side-effects of the UV-reduction process are further investigated. Published by Elsevier B.V.

  13. In Situ Synthesis of Silver Nanoparticles on the Polyelectrolyte-Coated Sericin/PVA Film for Enhanced Antibacterial Application.

    Science.gov (United States)

    Cai, Rui; Tao, Gang; He, Huawei; Guo, Pengchao; Yang, Meirong; Ding, Chaoxiang; Zuo, Hua; Wang, Lingyan; Zhao, Ping; Wang, Yejing

    2017-08-18

    To develop silk sericin (SS) as a potential antibacterial biomaterial, a novel composite of polyelectrolyte multilayers (PEMs) coated sericin/poly(vinyl alcohol) (SS/PVA) film modified with silver nanoparticles (AgNPs) has been developed using a layer-by-layer assembly technique and ultraviolet-assisted AgNPs synthesis method. Ag ions were enriched by PEMs via the electrostatic attraction between Ag ions and PEMs, and then reduced to AgNPs in situ with the assistance of ultraviolet irradiation. PEMs facilitated the high-density growth of AgNPs and protected the synthesized AgNPs due to the formation of a 3D matrix, and thus endowed SS/PVA film with highly effective and durable antibacterial activity. Scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, Fourier transfer infrared spectroscopy, water contact angle, mechanical property and thermogravimetric analysis were applied to characterize SS/PVA, PEMs-SS/PVA and AgNPs-PEMs-SS/PVA films, respectively. AgNPs-PEMs-SS/PVA film has exhibited good mechanical performance, hydrophilicity, water absorption capability as well as excellent and durable antibacterial activity against Escherichia coli , Staphylococcus aureus and Pseudomonas aeruginosa and good stability and degradability. This study has developed a simple method to design and prepare AgNPs-PEMs-SS/PVA film for potential antibacterial application.

  14. Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

    Directory of Open Access Journals (Sweden)

    Qing Yin

    2017-06-01

    Full Text Available Porous hypercross-linked polymers based on perbenzylated monosugars (SugPOP-1–3 have been synthesized by Friedel–Crafts reaction using formaldehyde dimethyl acetal as an external cross-linker. Three perbenzylated monosugars with similar chemical structure were used as monomers in order to tune the porosity. These obtained polymers exhibit microporous and mesoporous features. The highest Brunauer–Emmett–Teller specific surface area for the resulting polymers was found to be 1220 m2 g−1, and the related carbon dioxide storage capacity was found to be 14.4 wt % at 1.0 bar and 273 K. As the prepared porous polymer SugPOP-1 is based on hemiacetal glucose, Ag nanoparticles (AgNPs can be successfully incorporated into the polymer by an in situ chemical reduction of freshly prepared Tollens’ reagent. The obtained AgNPs/SugPOP-1 composite demonstrates good catalytic activity in the reduction of 4-nitrophenol (4-NP with an activity factor ka = 51.4 s−1 g−1, which is higher than some reported AgNP-containing composite materials.

  15. Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction.

    Science.gov (United States)

    Yin, Qing; Chen, Qi; Lu, Li-Can; Han, Bao-Hang

    2017-01-01

    Porous hypercross-linked polymers based on perbenzylated monosugars ( SugPOP-1-3 ) have been synthesized by Friedel-Crafts reaction using formaldehyde dimethyl acetal as an external cross-linker. Three perbenzylated monosugars with similar chemical structure were used as monomers in order to tune the porosity. These obtained polymers exhibit microporous and mesoporous features. The highest Brunauer-Emmett-Teller specific surface area for the resulting polymers was found to be 1220 m 2 g -1 , and the related carbon dioxide storage capacity was found to be 14.4 wt % at 1.0 bar and 273 K. As the prepared porous polymer SugPOP-1 is based on hemiacetal glucose, Ag nanoparticles (AgNPs) can be successfully incorporated into the polymer by an in situ chemical reduction of freshly prepared Tollens' reagent. The obtained AgNPs/ SugPOP-1 composite demonstrates good catalytic activity in the reduction of 4-nitrophenol (4-NP) with an activity factor k a = 51.4 s -1 g -1 , which is higher than some reported AgNP-containing composite materials.

  16. Preparation and Characterization of Chitosan-coated Fe3O4 Nanoparticles using Ex-Situ Co-Precipitation Method and Tripolyphosphate/Sulphate as Dual Crosslinkers

    Science.gov (United States)

    Wulandari, Ika O.; Mardila, Vita T.; Santjojo, D. J. Djoko H.; Sabarudin, Akhmad

    2018-01-01

    The unique properties of nanomaterial provide great opportunities to develop in several fields. Several types of nanoparticles have been proven beneficial for biomedical and therapeutic agent development. Particularly for clinical use, nanoparticles must be biocompatible and non-toxic. Iron oxide nanoparticles consist of either magnetite (Fe3O4) or maghemite (γ-Fe2O3) was eligible to use for in vivo application including targeting drug delivery. Due to their distinct properties, these nanoparticles could be directed to the specific target under external magnetic field. However, nanoparticles have a tendency to form agglomeration. Therefore, surface modification was required to reduce the agglomeration. In this study, nanoparticles of Fe3O4 were produced and coated by biomaterial (chitosan) using ex-situ co-precipitation method. Nanoparticles of Fe3O4 were synthesized by adding ammonia water into iron ferric and ferrous solution. Synthesis process of Fe3O4 was conducted prior to adding chitosan. Chitosan was then cross-linked by a combination of tripolyphosphate/sulphate. The different composition ratio and crosslinking time provide the different physical and magnetic characteristics of nanoparticles. Particle and crystallite size was determined by using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) respectively, whereas magnetic characteristic was determined by Electron Spin Resonance (ESR). The results showed that the ratio enhancement between chitosan: Fe3O4 increase the particle size, while decreased the crystallite size. Morphology and particle size were influenced by the ratio of crosslinkers. It was found that the higher tripolyphosphate content was contributed to the small size and more spherical morphology. In addition, the influence of crosslinking time toward crystallite size was determined by altering stirring time. The longer duration of crosslinking time, provide the larger crystallite size of chitosan-Fe3O4. There was an interesting

  17. In situ probing of intracellular pH by fluorescence from inorganic nanoparticles.

    Science.gov (United States)

    Guo, Junhong; Xiong, Shijie; Wu, Xinglong; Shen, Jiancang; Chu, Paul K

    2013-12-01

    Intracellular pH (pHi) plays a critical role in the physiological processes of cells. Nanoscale sensors based on pH-sensitive fluorescent proteins attached on nanoparticles (NPs) have been designed but inorganic NP-dependent fluorescent nanosensors have not yet been explored. Herein we describe a pH sensitive inorganic semiconductor fluorescent probe based on ultrathin 3C-SiC NPs which can effectively monitor pH in the range of 5.6-7.4 by taking advantage of the linear dependence between the fluorescent intensity ratio of the surface OH(-) and H(+) bonding states to band-to-band recombination and pH. Detection of pHi is demonstrated in living HeLa cells. In particular, pHi measurements during apoptosis confirm the validity and sensitivity of this technique in monitoring real-time changes in the intracellular environment. Toxicity assessment and confocal laser scanning microscopy indicate that the 3C-SiC NPs have low cytotoxicity and are compatible with living cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Observing reduction of 4-nitrobenzenthiol on gold nanoparticles in situ using surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Ren, Xiaoqian; Tan, Enzhong; Lang, Xiufeng; You, Tingting; Jiang, Li; Zhang, Hongyan; Yin, Penggang; Guo, Lin

    2013-09-14

    In this article, reduction of 4-nitrobenzenthiol (4-NBT) on Au nanoparticles (NPs) was characterized using surface-enhanced Raman scattering (SERS). Plasmon-driven chemical transformation from 4-NBT dimering into p,p'-dimercaptoazobenzene (DMAB) has been investigated on the surface of Au NPs. The laser power-dependent SERS spectra of 4-NBT on the surface of Au substrates were studied, and show that the laser power has an influence on the SERS signals of 4-NBT on Au NPs and production of DMAB by a plasmon-driven surface-catalyzed chemical reaction tends to be much easier under relative high laser power. Furthermore, we have used simple and efficient Au substrates (gold NPs with a size around 45 nm) exhibiting both catalytic properties and SERS activities to monitor the catalytic reaction of surface catalytic reaction process with borohydride solution. The experiments prove that the nitro-to-amino group conversion could be completed by borohydride at ambient conditions on Au substrates. Illuminated with high laser power, 4-NBT molecules and already formed DMAB molecules are further reduced into 4-aminobenzenthiol (4-ABT) by the addition of borohydride, While with low laser power 4-NBT molecules are transformed into 4-ABT with DMAB as the intermediate, which proves Au NPs are a mild and promising catalyst. Our studies might be helpful in extending the understanding of chemical reactions of 4-NBT and related research as well as providing a new strategy synthesis of azo dyes and anilines.

  19. Silicon nanoparticles as contrast agents in the methods of optical biomedical diagnostics

    Science.gov (United States)

    Zabotnov, S. V.; Kashaev, F. V.; Shuleiko, D. V.; Gongalsky, M. B.; Golovan, L. A.; Kashkarov, P. K.; Loginova, D. A.; Agrba, P. D.; Sergeeva, E. A.; Kirillin, M. Yu

    2017-07-01

    The efficiency of light scattering by nanoparticles formed using the method of picosecond laser ablation of silicon in water and by nanoparticles of mechanically grinded mesoporous silicon is compared. The ensembles of particles of both types possess the scattering coefficients sufficient to use them as contrast agents in optical coherence tomography (OCT), particularly in the range of wavelengths 700-1000 nm, where the absorption of both silicon and most biological and mimicking tissues is small. According to the Mie theory the main contribution to the scattering in this case is made by the particles having a relatively large size (150-300 nm). In the experiments on visualising the agar phantom surface by means of OCT, the contrast of the medium boundary, provided by nanoparticles amounted to 14 dB and 30 dB for the ablated particles and the porous silicon powder, respectively. The numerical simulation of OCT images of skin in the presence of nanoparticles, confirmed the efficiency of using them as a contrast agent.

  20. An Electrochemical, Point-of-Care Detector for Reagent-free, In-situ Diagnostics of Pathogens, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — For long-term exploratory space travel, there will be a critical need for in-situ diagnosis and assessment of biological specimens from symptomatic astronauts,...

  1. Structure Sensitivity in Pt Nanoparticle Catalysts for Hydrogenation of 1,3-Butadiene: In Situ Study of Reaction Intermediates Using SFG Vibrational Spectroscopy

    KAUST Repository

    Michalak, William D.

    2013-01-31

    The product selectivity during 1,3-butadiene hydrogenation on monodisperse, colloidally synthesized, Pt nanoparticles was studied under reaction conditions with kinetic measurements and in situ sum frequency generation (SFG) vibrational spectroscopy. SFG was performed with the capping ligands intact in order to maintain nanoparticle size by reduced sintering. Four products are formed at 75 C: 1-butene, cis-2-butene, trans-2-butene, and n-butane. Ensembles of Pt nanoparticles with average diameters of 0.9 and 1.8 nm exhibit a ∼30% and ∼20% increase in the full hydrogenation products, respectively, as compared to Pt nanoparticles with average diameters of 4.6 and 6.7 nm. Methyl and methylene vibrational stretches of reaction intermediates observed under working conditions using SFG were used to correlate the stable reaction intermediates with the product distribution. Kinetic and SFG results correlate with previous DFT predictions for two parallel reaction pathways of 1,3-butadiene hydrogenation. Hydrogenation of 1,3-butadiene can initiate with H-addition at internal or terminal carbons leading to the formation of 1-buten-4-yl radical (metallocycle) and 2-buten-1-yl radical intermediates, respectively. Small (0.9 and 1.8 nm) nanoparticles exhibited vibrational resonances originating from both intermediates, while the large (4.6 and 6.7 nm) particles exhibited vibrational resonances originating predominately from the 2-buten-1-yl radical. This suggests each reaction pathway competes for partial and full hydrogenation and the nanoparticle size affects the kinetic preference for the two pathways. The reaction pathway through the metallocycle intermediate on the small nanoparticles is likely due to the presence of low-coordinated sites. © 2012 American Chemical Society.

  2. Highly efficient removal of trace thallium from contaminated source waters with ferrate: Role of in situ formed ferric nanoparticle.

    Science.gov (United States)

    Liu, Yulei; Wang, Lu; Wang, Xianshi; Huang, Zhuangsong; Xu, Chengbiao; Yang, Tao; Zhao, Xiaodan; Qi, Jingyao; Ma, Jun

    2017-11-01

    Thallium (Tl) is highly toxic to mammals and relevant pollution cases are increasing world-widely. Convenient and efficient method for the removal of trace Tl from contaminated source water is imperative. Here, the removal of trace Tl by K 2 FeO 4 [Fe(VI)] was investigated for the first time, with the exploration of reaction mechanisms. Six different types of water treatment agents (powdered activated carbon, Al 2 (SO 4 ) 3 , FeCl 3 , δ-MnO 2 , MnO 2 nano-particles, and K 2 FeO 4 ) were used for the removal of Tl in spiked river water, and K 2 FeO 4 showed excellent removal performance. Over 92% of Tl (1 μg/L) was removed within 5 min by applying 2.5 mg/L of K 2 FeO 4 (pH 7.0, 20 °C). XPS analysis revealed that in the reaction of Tl(I) with K 2 FeO 4 , Tl(I) was oxidized to Tl(III), and removed by the K 2 FeO 4 reduced ferric particles. The removal of Tl by in situ formed and ex situ formed ferric particle was examined respectively, and the results revealed that the removal of trace Tl could be attributed to the combination of adsorption and coprecipitation processes. The hydrodynamic size of the reduced particle from K 2 FeO 4 ranged from 10 nm to 100 nm, and its surface was negatively charged under neutral pH condition. These factors were conducive for the efficient removal of Tl by K 2 FeO 4 . The effects of solution pH, coexisting ions (Na + , Ca 2+ , and HCO 3 - ), humic acid, solution temperature, and reductive environment on the removal and desorption of Tl were investigated, and the elimination of Tl in polluted river water and reservoir water was performed. These results suggest that K 2 FeO 4 could be an efficient and convenient agent on trace Tl removal. Copyright © 2017. Published by Elsevier Ltd.

  3. Methacrylate bonding to zirconia by in situ silica nanoparticle surface deposition.

    Science.gov (United States)

    Oliveira-Ogliari, Aline; Collares, Fabrício M; Feitosa, Victor P; Sauro, Salvatore; Ogliari, Fabrício A; Moraes, Rafael R

    2015-01-01

    This study introduces an innovative method to enhance adhesion of methacrylate-based cements to yttria-stabilized zirconia (Y-TZP) by means of a silica-nanoparticle deposition process. Two alkoxide organic precursors, tetraethyl-orthosilicate (TEOS) and zirconium tert-butoxide (ZTB) were diluted in hexane at different concentrations in order to obtain several experimental materials to enhance deposition of a SiO(x) reactive layer to Y-TZP. This deposition was attained via sintering alkoxide precursors directly on pre-sintered zirconia (infiltration method—INF) or application on the surface of fully sintered zirconia (coating method—COA). Untreated specimens and a commercial tribochemical silica coating were also tested as controls and all the treated Y-TZP specimens were analyzed using SEM-EDX. Specimens were bonded using silane, adhesive and dual-cure luting cement and submitted to shear bond strength test after different water storage periods (24 h, 3-, 6- and 12-months). SEM-EDX revealed Y-TZP surface covered by silica nanoclusters. The morphology of silica-covered Y-TZP surfaces was influenced by sintering method, employed to deposit nanoclusters. High bond strength (MPa) was observed when using COA method; highest TEOS percentage achieved the greatest bond strengths to Y-TZP surface (36.7±6.3 at 24 h). However, bonds stability was dependent on ZTB presence (32.9±9.7 at 3 months; 32.3±7.1 at 6 months). Regarding INF method, the highest and more stable resin-zirconia bond strength was attained when using experimental solutions containing TEOS and no ZTB. Both sintering methods tested in this study were able to achieve a bonding performance similar to that of classic tribochemical strategies. This study demonstrates that it is possible to achieve a reliable and long-lasting bonding between yttria-stabilized zirconia ceramic and methacrylate-based cements when using this novel, simple, and cost-effective bonding approach. Copyright © 2014 Academy of Dental

  4. In situ diagnostic of water distribution in thickness direction of MEA by neutron imaging. Focused on characteristics of water distribution in gas diffusion layer

    International Nuclear Information System (INIS)

    Tasaki, Yutaka; Ichikawa, Yasushi; Kobo, Norio; Shinohara, Kazuhiko; Boillat, Pierre; Kramer, Denis; Scherer, Gunther G.; Lehmann, Eberhard H.

    2008-01-01

    The mass transfer characteristics of gas diffusion layer (GDL) are closely related to cell performance in PEFC. In this study, In situ diagnostic of water distribution in thickness direction of MEA by Neutron Imaging has been carried out for three MEAs with different GDLs on cathode side as well as I-V characteristics. It was confirmed that this method is useful for analyzing water distribution in thickness direction of MEA. The relationship between I-V characteristics and liquid water distribution has been studied. (author)

  5. Exfoliation of Graphene Oxide Nanosheets from Pencil Lead and IN SITU Preparation of Gold Nanoparticles on Graphene Oxide Nanosheets

    Science.gov (United States)

    Boruah, Sontara Konwar; Boruah, Prabin Kumar; Sarma, Pradyut; Bezbaruah, Bipul; Medhi, Chitrani; Medhi, Okhil Kumar

    2013-01-01

    This work reports the low-cost exfoliation of graphene oxide (GO) from pencil lead using modified Hummer's method. The gold nanoparticles (AuNPs) supported on GO is prepared via an in situ bio reduction of HAuCl4 by polyphenolic biomolecules present in young leaves of tea (Camellia sinensis) extracted in the presence of GO. The UV-Visible absorption spectrum of GO dispersion in water exhibits two bands at 228 nm and a shoulder at 300 nm corresponding to π-π* transitions of aromatic C-C bonds and n-π* transitions of C=O bonds. In photoluminescence (PL) study, GO dispersion in water shows an emission band at 555 nm, when excited at 325 nm. When AuNPs are supported on GO nanosheets the bands at 228 nm and 300 nm of GO disappears and two new UV-Visible bands at 229 nm for π-π* (for C=C) and 550 nm for transverse surface plasmon resonance (TSPR) of AuNPs appears. When AuNPs are supported on GO nanosheets, PL emission band at 555 nm disappears and two new PL emission bands appear at 431 nm and 658 nm. The physical and morphological characterizations are performed by Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), High-resolution-transmission electron microscopy (HR-TEM) and BET surface area measurement. Morphological studies revealed that the GO nanosheets are well dispersed in water and AuNPs are supported on the GO nanosheets.

  6. Hybrid polymer-CdS solar cell active layers formed by in situ growth of CdS nanoparticles

    International Nuclear Information System (INIS)

    Masala, S.; Del Gobbo, S.; Borriello, C.; Bizzarro, V.; La Ferrara, V.; Re, M.; Pesce, E.; Minarini, C.; De Crescenzi, M.; Di Luccio, T.

    2011-01-01

    The integration of semiconductor nanoparticles (NPs) into a polymeric matrix has the potential to enhance the performance of polymer-based solar cells taking advantage of the physical properties of NPs and polymers. We synthesize a new class of CdS-NPs-based active layer employing a low-cost and low temperature route compatible with large-scale device manufacturing. Our approach is based on the controlled in situ thermal decomposition of a cadmium thiolate precursor in poly(3-hexylthiophene) (P3HT). The casted P3HT:precursor solid foils were heated up from 200 to 300 °C to allow the precursor decomposition and the CdS-NP formation within the polymer matrix. The CdS-NP growth was controlled by varying the annealing temperature. The polymer:precursor weight ratio was also varied to investigate the effects of increasing the NP volume fraction on the solar cell performances. The optical properties were studied by using UV–Vis absorption and photoluminescence (PL) spectroscopy at room temperature. To investigate the photocurrent response of P3HT:CdS nanocomposites, ITO/P3HT:CdS/Al solar cell devices were realized. We measured the external quantum efficiency (EQE) as a function of the wavelength. The photovoltaic response of the devices containing CdS-NPs showed a variation compared with the devices with P3HT only. By changing the annealing temperature the EQE is enhanced in the 400–600 nm spectral region. By increasing the NPs volume fraction remarkable changes in the EQE spectra were observed. The data are discussed also in relation to morphological features of the interfaces studied by Focused Ion Beam technique.

  7. Assessment of Laser Induced Ablation Spectroscopy (LIAS) as a method for quantitative in situ surface diagnostic in plasma environments

    International Nuclear Information System (INIS)

    Gierse, Niels Hannes Gustav

    2014-01-01

    In this work Laser Induced Ablation Spectroscopy (LIAS) is investigated as an in situ plasma surface interaction diagnostic for fusion reactors and fusion experiments. In LIAS an intensive laser pulse is used to ablate the material under investigation during plasma operation. Ablation products penetrate into the edge region of the plasma and are excited and ionized. In case of molecules and clusters additionally dissociation occurs. The emitted line radiation is observed by radiometric calibrated spectroscopy. Results from LIAS of W/C/Al/D-mixed layers and amorphous hydrocarbon layers are presented. Using a fast camera system time resolved measurements of the LIAS.process could be performed, allowing investigation of the temporal behavior of excitation, dissociation and ionization processes. For Tungsten, 90% of the LIAS light is observed within 10±3 μs after the laser pulse. In case of carbon within 20±3 μs. Additionally separation in time of LIAS emission and the LIBS emission caused by the laser pulse at the surface within single measurements was demonstrated. This allows the separate analysis of both processes in a coaxial setup which is foreseen for future experiments. The inverse photon efficiency of the Balmer D α -emission from LIAS of a-C:D-layers was found to be [(D)/(XB)] a-C:D LIAS → D D α =71±7. The plasma perturbation due to LIAS was investigated by laser energy density variation when ablating W/C/Al/D.mixed layers. Local plasma perturbation is found to increase with laser energy density. Balmer H γ /H δ - line intensity ratio measurements only show for ohmic discharges and the case of the lowest central density signs of local plasma perturbation in LIAS of graphite samples. A simple analytical model for local plasma perturbation during LIAS is introduced and evaluated. Qualitative agreement between the model and the above reported experimental observations is found; a stronger influence on local conditions is found by tungsten than by

  8. Mild in situ growth of platinum nanoparticles on multiwalled carbon nanotube-poly (vinyl alcohol) hydrogel electrode for glucose electrochemical oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shumin; Zheng, Yudong, E-mail: zhengyudong@mater.ustb.edu.cn; Qiao, Kun [University of Science and Technology Beijing, School of Material Science and Engineering (China); Su, Lei [University of Science and Technology Beijing, School of Chemistry and Biological Engineering (China); Sanghera, Amendeep; Song, Wenhui [University College London, UCL Centre for Nanotechnology & Regenerative Medicine, Division of Surgery and Interventional Science (United Kingdom); Yue, Lina; Sun, Yi [University of Science and Technology Beijing, School of Material Science and Engineering (China)

    2015-12-15

    This investigation describes an effective strategy to fabricate an electrochemically active hybrid hydrogel made from platinum nanoparticles that are highly dense, uniformly dispersed, and tightly embedded throughout the conducting hydrogel network for the electrochemical oxidation of glucose. A suspension of multiwalled carbon nanotubes and polyvinyl alcohol aqueous was coated on glassy carbon electrode by electrophoretic deposition and then physically crosslinked to form a three-dimensional porous conductive hydrogel network by a process of freezing and thawing. The network offered 3D interconnected mass-transport channels (around 200 nm) and confined nanotemplates for in situ growth of uniform platinum nanoparticles via the moderate reduction agent, ascorbic acid. The resulting hybrid hydrogel electrode membrane demonstrates an effective method for loading platinum nanoparticles on multiwalled carbon nanotubes by the electrostatic adsorption between multiwalled carbon nanotubes and platinum ions within porous hydrogel network. The average diameter of platinum nanoparticles is 37 ± 14 nm, which is less than the particle size by only using the moderate reduction agent. The hybrid hydrogel electrode membrane-coated glassy carbon electrode showed excellent electrocatalytic activity and good long-term stability toward glucose electrochemical oxidation. The glucose oxidation current exhibited a linear relationship with the concentration of glucose in the presence of chloride ions, promising for potential applications of implantable biofuel cells, biosensors, and electronic devices.

  9. Diagnostic Tools for Performance Evaluation of Innovative In-Situ Remediation Technologies at Chlorinated Solvent-Contaminated Sites

    Science.gov (United States)

    2011-07-01

    Bioremediation is non-hazardous to workers and the environment, destroys contaminants in situ, is relatively low maintenance, and minimizes disturbance of the...full-scale upflow anaerobic sludge blanket reactor treating poultry slaughterhouse wastewater.” Bioresource Tech. April 2008:2018-2024. DiStefano

  10. Diagnostic accuracy: theoretical models for preimplantation genetic testing of a single nucleus using the fluorescence in situ hybridization technique

    NARCIS (Netherlands)

    Scriven, P. N.; Bossuyt, P. M. M.

    2010-01-01

    The aim of this study was to develop and use theoretical models to investigate the accuracy of the fluorescence in situ hybridization (FISH) technique in testing a single nucleus from a preimplantation embryo without the complicating effect of mosaicism. Mathematical models were constructed for

  11. Immobilized organoruthenium(II) complexes onto polyethyleneimine-wrapped carbon nanotubes/in situ formed gold nanoparticles as a novel electrochemical sensing platform

    Energy Technology Data Exchange (ETDEWEB)

    Azadbakht, Azadeh, E-mail: Azadbakht.a@gmail.com; Abbasi, Amir Reza; Derikvand, Zohreh; Amraei, Shiba

    2015-03-01

    The polyethyleneimine (PEI) wrapped multi-walled carbon nanotubes functionalized with a carboxylic acid group (CNTs–COOH) gold nanoparticle (AuNP)-modified gold (Au) electrode has been utilized as a platform to immobilize organoruthenium(II) complexes (ORC). The surface structure and composition of the sensor were characterized by scanning electron microscopy (SEM). Electrocatalytic reduction of iodate and nitrite on the surface of modified electrode was investigated with cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and hydrodynamic voltammetry methods. The cyclic voltammetric results indicated the ability of AuNPs/PEI/CNT–COOH/ORC modified Au electrode to catalyze the reduction of this compound. AuNPs/PEI/CNTs–COOH nanocomposite combined the advantages of PEI-well dispersed CNTs–COOH and in situ formed AuNPs. - Highlights: • We prepared composite containing polyethyleneimine (PEI), CNTs and AuNPs. • AuNPs were in situ formed on the surface of CNTs–PEI. • When the AuNPs were in situ formed the stability would be improved. • Nanocomposite combined the advantages of PEI–CNTs and in situ formed AuNPs. • Modified nanocomposite Au electrode catalyzes the reduction of iodate and nitrite.

  12. Volmer-Weber growth stages of polycrystalline metal films probed by in situ and real-time optical diagnostics

    Science.gov (United States)

    Abadias, G.; Simonot, L.; Colin, J. J.; Michel, A.; Camelio, S.; Babonneau, D.

    2015-11-01

    The Volmer-Weber growth of high-mobility metal films is associated with the development of a complex compressive-tensile-compressive stress behavior as the film deposition proceeds through nucleation of islands, coalescence, and formation of a continuous layer. The tensile force maximum has been attributed to the end of the islands coalescence stage, based on ex situ morphological observations. However, microstructural rearrangements are likely to occur in such films during post-deposition, somewhat biasing interpretations solely based on ex situ analysis. Here, by combining two simultaneous in situ and real-time optical sensing techniques, based on surface differential reflectance spectroscopy (SDRS) and change in wafer curvature probed by multibeam optical stress sensor (MOSS), we provide direct evidence that film continuity does coincide with tensile stress maximum during sputter deposition of a series of metal (Ag, Au, and Pd) films on amorphous SiOx. Stress relaxation after growth interruption was testified from MOSS, whose magnitude scaled with adatom mobility, while no change in SDRS signal could be revealed, ruling out possible changes of the surface roughness at the micron scale.

  13. Synthesis, Characterization and Transport Properties of Novel Ion-exchange Nanocomposite Membrane Containing In-situ Formed ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    F. Heidary

    2015-10-01

    Full Text Available A  new  type  of  cation-exchange  nanocomposite  membranes  was prepared  by  in-situ  formation  of  ZnO  nanoparticles  in  a  blend containing  sulfonated  poly  (2,6-dimethyl-1,4-phenylene  oxide  and sulfonated polyvinylchloride  via  a  simple  one-step  chemical method.  As-synthesized  nanocomposite  membranes were characterized  using  Fourier  transform  infrared  spectroscopy, scanning  electron  microscopy  and X-ray  diffraction.  The  SEM images  showed  that  ZnO  nanoparticles  were  uniformly  dispersed throughout the polymeric matrices. The effect of additive loading on physicochemical and electrochemical properties of prepared cation-exchange  nanocomposite  membranes  was  studied.  Various characterizations revealed that  the  incorporation  of  different amounts  of  ZnO  nanoparticles  into  the  basic  membrane  structure had a significant influence on the membrane performance and could improve the electrochemical properties.

  14. Photo and biocatalytic activities along with UV protection properties on polyester fabric through green in-situ synthesis of cauliflower-like CuO nanoparticles.

    Science.gov (United States)

    Rezaie, Ali Bashiri; Montazer, Majid; Rad, Mahnaz Mahmoudi

    2017-11-01

    In this paper, a facile environmentally friendly method is introduced for in-situ synthesis and fabrication of cauliflower-like CuO nanoparticles on the polyester fabric to produce photo and biocatalytic activities with UV protection properties on polyester fabric. The ash of burnt leaves and stems of Seidlitzia rosmarinus plant called Keliab was used as a natural and nontoxic alkaline source for simultaneous synthesis of CuO nanoparticles and surface modification of polyester without using any other compounds. The images of field-emission scanning electron microscopy, patterns of energy-dispersive spectroscopy, UV-visible spectrum and X-ray diffraction confirmed successful synthesis and loading of CuO nanoparticles on the polyester fabric. The treated fabrics showed very good antibacterial activities toward two pathogen bacteria including Staphylococcus aureus as a Gram-positive and Escherichia coli as a Gram-negative bacteria with no adverse effects on human dermal fibroblasts based on MTT test. The treated fabrics confirmed significant photocatalytic activity for degradation of methylene blue under sunlight, self-cleaning properties under UV light and also UV protection properties. Further a colorant effect along with an improvement in the wettability and mechanical properties of the treated fabrics were indicated. Overall, this method can be applied as a clean route for producing photo and bio active textiles protecting against UV irradiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Photocatalytic property of a Bi2O3 nanoparticle modified BiOCl composite with a nanolayered hierarchical structure synthesized by in situ reactions.

    Science.gov (United States)

    Hu, Jiajia; Xu, Guangqing; Wang, Jinwen; Lv, Jun; Zhang, Xinyi; Xie, Ting; Zheng, Zhixiang; Wu, Yucheng

    2015-03-28

    A Bi2O3 nanoparticle modified BiOCl composite was synthesized by a solvothermal method combined with in situ reduction and oxidation in KBH4 and H2O2 solutions respectively. The thickness of a BiOCl nanosheet and the amount of Bi2O3 nanoparticle can be adjusted by changing the KBH4 concentration. The structure, morphology, elemental composition and optical absorption performance were characterized by using an X-ray diffraction diffractometer, a scanning electron microscope, a high resolution transmission electron microscope, an X-ray photoelectron spectroscope and a UV-Vis diffuse reflection spectroscope respectively. A nanolayered hierarchical structure of BiOCl was observed, and Bi2O3 nanoparticles were found to be evenly distributed on the surface/interface of the nanosheets. The photocatalytic activity of the composite was tested by the degradation of 40 mg L(-1) methyl orange solution under UV light illumination. The Bi2O3/BiOCl composite prepared in a KBH4 concentration of 0.02 M achieved the highest photocatalytic rate of 95.7% in 8 min under UV light illumination with a kinetic constant of 0.3125 l min(-1). The photocatalytic mechanism of the composite has been discussed.

  16. Dynamic Probing of Nanoparticle Stability In Vivo: A Liposomal Model Assessed Using In Situ Microdialysis and Optical Imaging

    OpenAIRE

    Jeng, Chien-Chung; Cheng, Shih-Hsun; Ho, Ja-an Annie; Huang, Sam Hong-Yi; Chang, Jerry C.; Tsai, Pi-Ju; Yang, Chung-Shi; Lo, Leu-Wei

    2011-01-01

    Nanoparticle-mediated drug delivery and controlled release has been a vigorous research area in contemporary nanomedicine. The in vivo stability of nanoparticle delivered on site is a prerequisite for the design of drug-controlled release by any means. In this study, the first methodology comprised of microdialysis and optical imaging to assess the liposome stability in vivo is reported. Macroscopically, we demonstrated the DPPG liposomes with negative surface charge fast accumulated in the ...

  17. Synthesis of in-situ luminescent ZnS nanoparticles facile with CTAB micelles and their properties study

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Vaishali [Centre for Nanoscience, Central University of Gujarat, Gandhinagar (India); Singh, Man [School of Chemical Sciences, Central University of Gujarat, Gandhinagar, India Telephone: 079-23260210, fax: 079-23260076 (India)

    2016-04-13

    Currently, the development of micelles route is thrust area of research in nanoscience for the control particle size and remarkable properties through chemical co-precipitation method. A 0.9 mM aqueous CTAB micellar solution plays a role as capping agent in the homogeneous solution of 0.5 M ZnSO{sub 4} and 0.5 M Na{sub 2}S for synthesis, further precipitates purified with centrifugation in cold ethanol and millipore water to remove unreacted reagents and ionic salt particles. A resultant, white colored luminescent ZnS nanoparticle out with ∼95% yield is reported. The ZnS nanoparticles have been examined by their luminescence properties, optical properties and crystal structure. The mean particle size of ZnS nanoparticles is found to be ∼10 nm in various technical results and UV-absorption was 80 nm blue shifts moved from 345 nm (bulk material) to 265 nm, showing a quantum size impact. The X-ray diffraction (XRD) pattern shows the immaculate cubic phase. Photoluminescence (PL) investigates the recombination mechanism with blue emission from shallow electron traps at 490 nm in ZnS nanoparticles. An FTIR spectrum and Thermal gravimetric analysis (TGA) gives confirmation of CTAB – cationic surfactant on surface of ZnS nanoparticle as capping agent as well thermal stability of CTAB capped ZnS nanoparticles with respect to temperature.

  18. Probing suitable therapeutic nanoparticles for controlled drug delivery and diagnostic reproductive health biomarker development

    Energy Technology Data Exchange (ETDEWEB)

    Jha, Rakhi [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); National Institute of Animal Welfare, Ministry of Environment, Forest and Climate Change, Faridabad, Haryana 121 004 (India); Jha, Pradeep K., E-mail: jha.rk.pk@gmail.com [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); Gupta, Santosh; Bhuvaneshwaran, S.P. [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); Hossain, Maidul [Department of Chemistry & Chemical Technology, Vidyasagar University, Midnapore 721102 (India); Guha, Sujoy K. [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India)

    2016-04-01

    Nanomaterial mediated drug delivery represents a highly promising technique while its selectivity for reproductive healthcare application still remains a challenge. Since the delicate structure and functional role of reproductive tissue and gametes require the use of biocompatible nanomedicine/devices that do not affect fertility or the development of resulting offspring, this paper reports an intercomparative study of human spermatozoa interaction with three different nanoparticles (NPs) namely; iron oxide (Fe{sub 3}O{sub 4)}, multiwalled carbon nanotubes (MWCNT) and graphene platelet nanopowder (GPN) to probe their suitability for drug delivery carrier and biomarker development purposes. ATR–FTIR results revealed that the sperm cell interaction with GPN had maximum amide I absorption for cell proteins and C=O stretching of the peptide backbone at the band around 1657 cm{sup −1} followed by iron oxide NPs whereas MWCNT had no absorption. These results showed that GPN followed by iron oxide NPs got maximally entrapped by cell membrane protein with maximum disruption but MWCNT exhibited less entrapment but significantly higher internalization which was further validated by morphological analysis of these cell NP interaction by SEM, HRTEM and fluorescence microscopy. The uptake kinetics and penetration mechanism of NPs were examined with isothermal titration calorimetry (ITC). Interestingly, ITC results confirmed ATR–FTIR and morphological observations that the binding of GPN and Fe{sub 3}O{sub 4} NPs with cell was exothermic and their bindings were favored by both negative enthalpy and positive entropy whereas in the case of MWCNT it was endothermic supported by unfavorable positive enthalpy and a favorable entropy change. Hence, it was evident that MWCNT had better internalization efficiency without disrupting the sperm lipid membrane compared to Fe{sub 3}O{sub 4} and GPN NPs. Therefore, this work proposes CNT as promising means. - Highlights: • Biophysical

  19. In situ preparation of magnetic Fe3O4 nanoparticles inside nanoporous poly(L-glutamic acid)/chitosan microcapsules for drug delivery.

    Science.gov (United States)

    Yan, Shifeng; Zhang, Xin; Sun, Yuanyuan; Wang, Taotao; Chen, Xuesi; Yin, Jingbo

    2014-01-01

    The magnetic polymer microcapsules, as a promising environmental stimuli-responsive delivery vehicle, have been increasingly exploited to tackle the problem of remotely navigated delivery. This study presented a novel design and fabrication of magnetic poly(L-glutamic acid)/chitosan (PGA/CS) microcapsules. Magnetic Fe3O4 nanoparticles were in situ synthesized inside nanoporous PGA/CS microcapsules and resultant magnetic PGA/CS microcapsules were characterized. Mitoxantrone (MTX), an antineoplastic drug, was chosen as a water-soluble model drug to research the loading and release properties of the microcapsules. The results showed the carboxylate groups of PGA within polyelectrolyte walls could be used as binding sites for the absorption of iron ions and reaction sites for the synthesis of magnetic nanoparticles. Magnetic PGA/CS microcapsules were dissected using a dual-beam scanning electron microscope/focused ion beam (SEM/FIB) for morphological and microstructural examination. It was found that Fe3O4 nanoparticles with size of about 10nm were homogeneously dispersed in the polymer matrix and adhered to the pore walls of the microcapsules. Increasing the concentration of iron ions led to an increasing loading content of Fe3O4 nanoparticles and an increase in the resultant magnetization. The magnetic PGA/CS microcapsules could be easily manipulated by an external magnetic field. The MTX loading capacity depended on loading time and MTX concentration. The high loading could be ascribed to spontaneous deposition of MTX induced by electrostatic interaction. The microcapsules exhibited sustained release behavior. The MTX release from microcapsules could be best described using Korsmeyer-Peppas and Baker-Lonsdale models, indicating the diffusion mechanism of drug release from both PGA/CS microcapsules and magnetic PGA/CS microcapsules. Therefore, the novel magnetic PGA/CS microcapsules are expected to find application in drug delivery systems because of the properties

  20. In situ diagnostic of two-phase flow phenomena in polymer electrolyte fuel cells by neutron imaging

    International Nuclear Information System (INIS)

    Zhang Jianbo; Kramer, Denis; Shimoi, Ryoichi; Ono, Yoshitaka; Lehmann, Eberhard; Wokaun, Alexander; Shinohara, Kazuhiko; Scherer, Guenther G.

    2006-01-01

    The formation of liquid water in operating polymer electrolyte fuel cells (PEFC) of industrial and laboratory size has been investigated by in situ neutron imaging. The influence of the materials chosen for the structural components of the cell on droplet formation and transport in flow fields and on liquid formation in gas diffusion layers has been studied. The changing of the cathodic gas diffusion layer material allowed the relationship between materials, liquid accumulation, and electrochemical performance to be examined. It has been shown that material choice has considerable bearing on the presence of liquid inside the porous structures and the electrochemical characteristics. A simplified quasi one-dimensional cell with an active area of 25 cm 2 was used for materials comparison, and the results were related to technically relevant operating conditions - where inhomogeneities have to be considered - by subsequent examination of cells with an active area of 100 cm 2

  1. Diagnostics of common microdeletion syndromes using fluorescence in situ hybridization: single center experience in a developing country

    Directory of Open Access Journals (Sweden)

    Amina Kurtovic-Kozaric

    2016-03-01

    Full Text Available Microdeletion syndromes are caused by chromosomal deletions of less than 5 megabases which can be detected by fluorescence in situ hybridization (FISH. We evaluated the most commonly detected microdeletions for the period from June 01, 2008 to June 01, 2015 in the Federation of Bosnia and Herzegovina, including DiGeorge, Prader-Willi/Angelman, Wolf-Hirschhorn, and Williams syndromes. We report 4 patients with DiGeorge syndromes, 4 patients with Prader-Willi/Angelman, 4 patients with Wolf-Hirschhorn syndrome, and 3 patients with Williams syndrome in the analyzed 7 year period. Based on the positive FISH results for each syndrome, the incidence was calculated for the Federation of Bosnia and Herzegovina. These are the first reported frequencies of the microdeletion syndromes in the Federation of Bosnia and Herzegovina.

  2. Diagnostic plasma of diode discharge containing carbon particles and ex situ analysis of resulting powders; Diagnostic plasma d'une decharge diode contenant des poussieres carbonees et analyses ex situ des poudres formees

    Energy Technology Data Exchange (ETDEWEB)

    Hugon, R.; Peng, Y.; Vasseur, J.L.; Bougdira, J. [Nancy-1 Univ. Henri Poincare, Laboratoire de Physique des Milieux Ionises et Applications, UMR 7040 CNRS, 54 - Vandoeuvre-les-Nancy (France)

    2006-07-01

    The problem of wall-plasma interaction are very important for the tokamaks development and in particular the new reactor ITER. The carbon fiber walls erosion in contact with the plasma leads to the formation of carbon particles as dust or hydrocarbon deposits, responsible of the fuel retention (deuterium, tritium). In this study, carbon dust is produced in a laboratory reactor type diode. The time dependence of the gaseous phase reactivity and its influence on the electric characteristics of the discharge and the dust formation dynamic, in function of the power and the gaseous mixture are realized with different types of diagnostic. The dust formation dynamic is studied by laser diffusion. (A.L.B.)

  3. A Combined SAXS/SANS Study for the in Situ Characterization of Ligand Shells on Small Nanoparticles: The Case of ZnO.

    Science.gov (United States)

    Schindler, T; Schmiele, M; Schmutzler, T; Kassar, T; Segets, D; Peukert, W; Radulescu, A; Kriele, A; Gilles, R; Unruh, T

    2015-09-22

    ZnO nanoparticles (NPs) have great potential for their use in, e.g., thin film solar cells due to their electro-optical properties adjustable on the nanoscale. Therefore, the production of well-defined NPs is of major interest. For a targeted production process, the knowledge of the stabilization layer of the NPs during and after their formation is of particular importance. For the study of the stabilizer layer of ZnO NPs prepared in a wet chemical synthesis from zinc acetate, only ex situ studies have been performed so far. An acetate layer bound to the surface of the dried NPs was found; however, an in situ study which addresses the stabilizing layer surrounding the NPs in a native dispersion was missing. By the combination of small angle scattering with neutrons and X-rays (SANS and SAXS) for the same sample, we are now able to observe the acetate shell in situ for the first time. In addition, the changes of this shell could be followed during the ripening process for different temperatures. With increasing size of the ZnO core (d(core)) the surrounding shell (d(shell)) becomes larger, and the acetate concentration within the shell is reduced. For all samples, the shell thickness was found to be larger than the maximum extension of an acetate molecule with acetate concentrations within the shell below 50 vol %. Thus, there is not a monolayer of acetate molecules that covers the NPs but rather a swollen shell of acetate ions. This shell is assumed to hinder the growth of the NPs to larger macrostructures. In addition, we found that the partition coefficient μ between acetate in the shell surrounding the NPs and the total amount of acetate in the solution is about 10% which is in good agreement with ex situ data determined by thermogravimetric analysis.

  4. In situ synthesis of silver-nanoparticles/bacterial cellulose composites for slow-released antimicrobial wound dressing.

    Science.gov (United States)

    Wu, Jian; Zheng, Yudong; Song, Wenhui; Luan, Jiabin; Wen, Xiaoxiao; Wu, Zhigu; Chen, Xiaohua; Wang, Qi; Guo, Shaolin

    2014-02-15

    Bacterial cellulose has attracted increasing attention as a novel wound dressing material, but it has no antimicrobial activity, which is one of critical skin-barrier functions in wound healing. To overcome such deficiency, we developed a novel method to synthesize and impregnate silver nanoparticles on to bacterial cellulose nanofibres (AgNP-BC). Uniform spherical silver nano-particles (10-30 nm) were generated and self-assembled on the surface of BC nano-fibers, forming a stable and evenly distributed Ag nanoparticles coated BC nanofiber. Such hybrid nanostructure prevented Ag nanoparticles from dropping off BC network and thus minimized the toxicity of nanoparticles. Regardless the slow Ag(+) release, AgNP-BC still exhibited significant antibacterial activities with more than 99% reductions in Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, AgNP-BC allowed attachment and growth of epidermal cells with no cytotoxicity emerged. The results demonstrated that AgNP-BC could reduce inflammation and promote wound healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Evaluation of In-Situ Magnetic Signals from Iron Oxide Nanoparticle-Labeled PC12 Cells by Atomic Force Microscopy.

    Science.gov (United States)

    Wang, Lijun; Min, Yue; Wang, Zhigang; Riggio, Cristina; Calatayud, M Pilar; Pinkernelle, Josephine; Raffa, Vittoria; Goya, Gerardo F; Keilhoff, Gerburg; Cuschieri, Alfred

    2015-03-01

    The magnetic signals from magnetite nanoparticle-labeled PC12 cells were assessed by magnetic force microscopy by deploying a localized external magnetic field to magnetize the nanoparticles and the magnetic tip simultaneously so that the interaction between the tip and PC12 cell-associated Fe3O4 nanoparticles could be detected at lift heights (the distance between the tip and the sample) larger than 100 nm. The use of large lift heights during the raster scanning of the probe eliminates the non-magnetic interference from the complex and rugged cell surface and yet maintains the sufficient sensitivity for magnetic detection. The magnetic signals of the cell-bound nanoparticles were semi-quantified by analyzing cell surface roughness upon three-dimensional reconstruction generated by the phase shift of the cantilever oscillation. The obtained data can be used for the evaluation of the overall cellular magnetization as well as the maximum magnetic forces from magnetic nanoparticle-labeled cells which is crucial for the biomedical application of these nanomaterials.

  6. Ex-Situ Synthesis of Polyvinyl alcohol(PVA)-coated Fe3O4 Nanoparticles by Coprecipitation-Ultrasonication Method

    Science.gov (United States)

    Riva’i, Imam; Oktavia Wulandari, Ika; Sulistyarti, Hermin; Sabarudin, Akhmad

    2018-01-01

    In this study, the synthesis of Fe3O4 nanoparticles was done with surface modification using PVA with coprecipitation-ultrasonication method. Time variations and PVA concentrations were added to determine the effect on crystallite size and lattice parameters on the synthesis of Fe3O4-PVA nanoparticles. Fe3O4 characterization was done using X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) instruments. FTIR was employed to determine PVA coating on the surface of Fe3O4 nanoparticles. The crystallite size and lattice parameters were analyzed using XRD. From the FTIR data, it is known that the interaction between PVA and Fe3O4 nanoparticles is characterized by Fe-O-C group at 1100 cm-1 region which is characteristic of Fe3O4-PVA nanoparticles, C-H groups of PVA in the range of 2950 cm-1 wave number, C-C of PVA regions of wave number 1405 cm-1, Fe3O4 and Fe3O4-PVA samples are in the range of 565 cm-1. In addition, the variation of ultrasonication time and the addition of PVA concentration have an effect on the crystallite size change and the lattice parameter observed from the XRD data. The use of ultrasonication time will affect the size of the crystallite become smaller and the grating lattice parameters obtained are wider. The effect of addition of PVA showed that higher concentration of PVA resulted in smaller crystallite size and larger lattice parameters. These results indicated that ultrasonication time and addition of PVA concentration greatly affect the characteristics of nanoparticles.

  7. A Reactive Oxide Overlayer on Rh Nanoparticles during CO Oxidation and Its Size Dependence Studied by in Situ Ambient Pressure XPS

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael E.; Zhang, Yawen; Butcher, Derek R.; Park, Jeong Y.; Li, Yimin; Bluhm, Hendrik; Bratlie, Kaitlin M.; Zhang, Tianfu; Somorjai, Gabor A.

    2008-09-15

    CO oxidation is one of the most studied heterogeneous reactions, being scientifically and industrially important, particularly for removal of CO from exhaust streams and preferential oxidation for hydrogen purification in fuel cell applications. The precious metals Ru, Rh, Pd, Pt, and Au are most commonly used for this reaction because of their high activity and stability. Despite the wealth of experimental and theoretical data, it remains unclear what is the active surface for CO oxidation under catalytic conditions for these metals. In this communication, we utilize in situ synchrotron ambient pressure X-ray photoelectron spectroscopy (APXPS) to monitor the oxidation state at the surface of Rh nanoparticles during CO oxidation and demonstrate that the active catalyst is a surface oxide, the formation of which is dependent on particle size. The amount of oxide formed and the reaction rate both increase with decreasing particle size.

  8. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  9. In situ fabrication of silver nanoparticle-filled hydrogen titanate nanotube layer on metallic titanium surface for bacteriostatic and biocompatible implantation

    Directory of Open Access Journals (Sweden)

    Wang Z

    2013-08-01

    Full Text Available Zheng Wang,1 Yan Sun,1 Dongzhou Wang,2 Hong Liu,2 Robert I Boughton31Department of Cardiology, Heilongjiang Provincial Hospital, Haerbin, Heilongjiang, People’s Republic of China; 2State Key Laboratory of Crystal Materials, Shandong University, Jinan, People’s Republic of China; 3Department of Physics and Astronomy, Bowling Green State University, Bowling Green, OH, USAAbstract: A silver nanoparticle (AgNP-filled hydrogen titanate nanotube layer was synthesized in situ on a metallic titanium substrate. In the synthesis approach, a layer of sodium titanate nanotubes is first prepared on the titanium surface by using a hydrothermal method. Silver nitrate solution is absorbed into the nanotube channels by immersing a dried nanotube layer in silver nitrate solution. Finally, silver ions are reduced by glucose, leading to the in situ growth of AgNPs in the hydrogen titanate nanotube channels. Long-term silver release and bactericidal experiments demonstrated that the effective silver release and effective antibacterial period of the titanium foil with a AgNP-filled hydrogen titanate nanotube layer on the surface can extend to more than 15 days. This steady and prolonged release characteristic is helpful to promote a long-lasting antibacterial capability for the prevention of severe infection after surgery. A series of antimicrobial and biocompatible tests have shown that the sandwich nanostructure with a low level of silver loading exhibits a bacteriostatic rate as high as 99.99%, while retaining low toxicity for cells and possessing high osteogenic potential. Titanium foil with a AgNP-filled hydrogen titanate nanotube layer on the surface that is fabricated with low-cost surface modification methods is a promising implantable material that will find applications in artificial bones, joints, and dental implants.Keywords: titanium implant, silver nanoparticle filling, ion substitution, bacteriostasis, cytocompatibility

  10. Loose nanofiltration membrane for dye/salt separation through interfacial polymerization with in-situ generated TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qi; Fan, Lin; Yang, Zhen; Zhang, Runnan; Liu, Ya-nan; He, Mingrui [Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072 (China); Su, Yanlei, E-mail: suyanlei@tju.edu.cn [Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072 (China); Jiang, Zhongyi [Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072 (China)

    2017-07-15

    Highlights: • A in-situ generated TiO{sub 2} approach was used to fabricate loose nanofiltration membrane. • The membrane contained small channels owing to the interaction between TiO{sub 2} and the polyamide. • The membranes exhibited high water fluxes and separation performance for dye/salt solutions. - Abstract: In this study, a high flux nanofiltration (NF) membrane with hybrid polymer-nanoparticle active layer was fabricated by chemical crosslinking of piperazine (PIP) and 1, 3, 5-benzene tricarbonyl trichloride (TMC). An in-situ generated method was applied to deposit titanium dioxide (TiO{sub 2}) nanoparticles uniformly on the membrane surface, leading to the enhancement of the surface hydrophilicity, roughness and relative surface area of the polyamide (PA) layer. The morphology of the modified membrane was investigated by scanning electron microscopy (SEM) and Atomic force microscopy (AFM), also energy dispersive X-ray microanalysis (EDX) was used to analyze the distribution of Ti element. Chemical structure was observed by Fourier transmission infrared attenuated total reflectance (FTIR-ATR) spectroscopy. Remarkably, the optimal water flux of the loose NF membrane was 65.0 Lm{sup −2} h{sup −1} bar{sup −1} nearly 5 times as much as the pure PA membrane flux. The rejections of the loose NF membranes for dyes were almost all greater than 95.0%, while the rejection for sodium sulfate (Na{sub 2}SO{sub 4}) was only about 17.0%, which indicated that the modified membrane had an impressive potential application for dye desalination and purification.

  11. nanoparticles

    Science.gov (United States)

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

    2014-10-01

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

  12. Proximity hybridization-regulated catalytic DNA hairpin assembly for electrochemical immunoassay based on in situ DNA template-synthesized Pd nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Fuyi [School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116 (China); Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical College, 221004, Xuzhou (China); Yao, Yao; Luo, Jianjun; Zhang, Xing; Zhang, Yu; Yin, Dengyang [Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical College, 221004, Xuzhou (China); Gao, Fenglei, E-mail: jsxzgfl@sina.com [Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical College, 221004, Xuzhou (China); Wang, Po, E-mail: wangpo@jsnu.edu.cn [School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116 (China)

    2017-05-29

    Novel hybridization proximity-regulated catalytic DNA hairpin assembly strategy has been proposed for electrochemical immunoassay based on in situ DNA template-synthesized Pd nanoparticles as signal label. The DNA template-synthesized Pd nanoparticles were characterized with atomic force microscopic and X-ray photoelectron spectroscopy. The highly efficient electrocatalysis by DNA template synthesized Pd nanoparticles for NaBH{sub 4} oxidation produced an intense detection signal. The label-free electrochemical method achieved the detection of carcinoembryonic antigen (CEA) with a linear range from 10{sup −15} to 10{sup −11} g mL{sup −1} and a detection limit of 0.43 × 10{sup −15} g mL{sup −1}. Through introducing a supersandwich reaction to increase the DNA length, the electrochemical signal was further amplified, leading to a detection limit of 0.52 × 10{sup −16} g mL{sup −1}. And it rendered satisfactory analytical performance for the determination of CEA in serum samples. Furthermore, it exhibited good reproducibility and stability; meanwhile, it also showed excellent specificity due to the specific recognition of antigen by antibody. Therefore, the DNA template synthesized Pd nanoparticles based signal amplification approach has great potential in clinical applications and is also suitable for quantification of biomarkers at ultralow level. - Graphical abstract: A novel label-free and enzyme-free electrochemical immunoassay based on proximity hybridization-regulated catalytic DNA hairpin assemblies for recycling of the CEA. - Highlights: • A novel enzyme-free electrochemical immunosensor was developed for detection of CEA. • The signal amplification was based on catalytic DNA hairpin assembly and DNA-template-synthesized Pd nanoparticles. • The biosensor could detect CEA down to 0.52 × 10{sup −16} g mL{sup −1} level with a dynamic range spanning 5 orders of magnitude.

  13. Catalyst-Free Conjugation and In Situ Quantification of Nanoparticle Ligand Surface Density Using Fluorogenic Cu-Free Click Chemistry

    DEFF Research Database (Denmark)

    Jølck, Rasmus Irming; Sun, Honghao; Berg, Rolf Henrik

    2011-01-01

    A highly efficient method for functionalizing nanoparticles and directly quantifying conjugation efficiency and ligand surface density has been developed. Attachment of 3-azido-modifed RGD-peptides to PEGylated liposomes was achieved by using Cu-free click conditions. Upon coupling a fluorophore ...

  14. Preparation and application of conducting polymer/Ag/clay composite nanoparticles formed by in situ UV-induced dispersion polymerization

    Science.gov (United States)

    Zang, Limin; Qiu, Jianhui; Yang, Chao; Sakai, Eiichi

    2016-02-01

    In this work, composite nanoparticles containing polypyrrole, silver and attapulgite (PPy/Ag/ATP) were prepared via UV-induced dispersion polymerization of pyrrole using ATP clay as a templet and silver nitrate as photoinitiator. The effects of ATP concentration on morphology, structure and electrical conductivity were studied. The obtained composite nanoparticles with an interesting beads-on-a-string morphology can be obtained in a short time (10 min), which indicates the preparation method is facile and feasible. To explore the potential applications of the prepared PPy/Ag/ATP composite nanoparticles, they were served as multifunctional filler and blended with poly(butylene succinate) (PBS) matrix to prepare biodegradable composite material. The distribution of fillers in polymer matrix and the interfacial interaction between fillers and PBS were confirmed by scanning electron microscope, elemental mapping and dynamic mechanical analysis. The well dispersed fillers in PBS matrix impart outstanding antibacterial property to the biodegradable composite material as well as enhanced storage modulus due to Ag nanoparticles and ATP clay. The biodegradable composite material also possesses modest surface resistivity (106 ~ 109 Ω/◻).

  15. Nucleation and growth of gold nanoparticles studied via in situ small angle X-ray scattering at millisecond time resolution.

    Science.gov (United States)

    Polte, Jörg; Erler, Robert; Thünemann, Andreas F; Sokolov, Sergey; Ahner, T Torsten; Rademann, Klaus; Emmerling, Franziska; Kraehnert, Ralph

    2010-02-23

    Gold nanoparticles (AuNP) were prepared by the homogeneous mixing of continuous flows of an aqueous tetrachloroauric acid solution and a sodium borohydride solution applying a microstructured static mixer. The online characterization and screening of this fast process ( approximately 2 s) was enabled by coupling a micromixer operating in continuous-flow mode with a conventional in-house small angle X-ray scattering (SAXS) setup. This online characterization technique enables the time-resolved investigation of the growth process of the nanoparticles from an average radius of ca. 0.8 nm to about 2 nm. To the best of our knowledge, this is the first demonstration of a continuous-flow SAXS setup for time-resolved studies of nanoparticle formation mechanisms that does not require the use of synchrotron facilities. In combination with X-ray absorption near edge structure microscopy, scanning electron microscopy, and UV-vis spectroscopy the obtained data allow the deduction of a two-step mechanism of gold nanoparticle formation. The first step is a rapid conversion of the ionic gold precursor into metallic gold nuclei, followed by particle growth via coalescence of smaller entities. Consequently it could be shown that the studied synthesis serves as a model system for growth driven only by coalescence processes.

  16. Preparation and application of conducting polymer/Ag/clay composite nanoparticles formed by in situ UV-induced dispersion polymerization.

    Science.gov (United States)

    Zang, Limin; Qiu, Jianhui; Yang, Chao; Sakai, Eiichi

    2016-02-03

    In this work, composite nanoparticles containing polypyrrole, silver and attapulgite (PPy/Ag/ATP) were prepared via UV-induced dispersion polymerization of pyrrole using ATP clay as a templet and silver nitrate as photoinitiator. The effects of ATP concentration on morphology, structure and electrical conductivity were studied. The obtained composite nanoparticles with an interesting beads-on-a-string morphology can be obtained in a short time (10 min), which indicates the preparation method is facile and feasible. To explore the potential applications of the prepared PPy/Ag/ATP composite nanoparticles, they were served as multifunctional filler and blended with poly(butylene succinate) (PBS) matrix to prepare biodegradable composite material. The distribution of fillers in polymer matrix and the interfacial interaction between fillers and PBS were confirmed by scanning electron microscope, elemental mapping and dynamic mechanical analysis. The well dispersed fillers in PBS matrix impart outstanding antibacterial property to the biodegradable composite material as well as enhanced storage modulus due to Ag nanoparticles and ATP clay. The biodegradable composite material also possesses modest surface resistivity (10(6)~ 10(9) Ω/◻).

  17. In situ growth of CdS nanoparticles on UiO-66 metal-organic framework octahedrons for enhanced photocatalytic hydrogen production under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jian-Jian; Wang, Rong; Liu, Xin-Ling; Peng, Fu-Min [School of Chemistry and Chemical Engineering and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230601 (China); Li, Chuan-Hao, E-mail: chuanhao.li@yale.edu [School of Chemistry and Chemical Engineering and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230601 (China); Department of Chemical & Environmental Engineering, Yale University, New Haven 06511 (United States); Teng, Fei [Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Yuan, Yu-Peng, E-mail: yupengyuan@ahu.edu.cn [School of Chemistry and Chemical Engineering and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230601 (China); Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China)

    2015-08-15

    Graphical abstract: Enhanced photocatalytic hydrogen generation was achieved though constructing the CdS/UiO-66 MOF hybrids. In addition, the resultant hybrids show excellent photostability for hydrogen generation. - Highlights: • CdS nanoparticles were hydrothermally grown on UiO-66 octahedrons. • The resultant CdS/UiO-66 hybrids show enhanced photocatalytic H{sub 2} generation under visible light irradiation. • CdS/UiO-66 hybrids possess excellent photostability for long-term hydrogen generation. - Abstract: CdS nanoparticles acting as photosensitizer was grown in situ upon UiO-66 metal-organic framework octahedrons through a hydrothermal process. The resultant CdS/UiO-66 hybrid photocatalysts show remarkably active hydrogen evolution under visible light irradiation as compared to CdS and UiO-66 alone. The optimum hybrid with 16 wt% CdS loading shows a hydrogen production rate of 235 μmol h{sup −1}, corresponding to 1.2% quantum efficiency at 420 nm. The improved photocatalytic hydrogen production over hybrid CdS/UiO-66 is ascribed to the efficient interfacial charge transfer from CdS to UiO-66, which effectively suppresses the recombination of photogenerated electron-hole pairs and thereby enhancing the photocatalytic efficiency.

  18. Loose nanofiltration membrane for dye/salt separation through interfacial polymerization with in-situ generated TiO2 nanoparticles

    Science.gov (United States)

    Zhang, Qi; Fan, Lin; Yang, Zhen; Zhang, Runnan; Liu, Ya-nan; He, Mingrui; Su, Yanlei; Jiang, Zhongyi

    2017-07-01

    In this study, a high flux nanofiltration (NF) membrane with hybrid polymer-nanoparticle active layer was fabricated by chemical crosslinking of piperazine (PIP) and 1, 3, 5-benzene tricarbonyl trichloride (TMC). An in-situ generated method was applied to deposit titanium dioxide (TiO2) nanoparticles uniformly on the membrane surface, leading to the enhancement of the surface hydrophilicity, roughness and relative surface area of the polyamide (PA) layer. The morphology of the modified membrane was investigated by scanning electron microscopy (SEM) and Atomic force microscopy (AFM), also energy dispersive X-ray microanalysis (EDX) was used to analyze the distribution of Ti element. Chemical structure was observed by Fourier transmission infrared attenuated total reflectance (FTIR-ATR) spectroscopy. Remarkably, the optimal water flux of the loose NF membrane was 65.0 Lm-2 h-1 bar-1 nearly 5 times as much as the pure PA membrane flux. The rejections of the loose NF membranes for dyes were almost all greater than 95.0%, while the rejection for sodium sulfate (Na2SO4) was only about 17.0%, which indicated that the modified membrane had an impressive potential application for dye desalination and purification.

  19. Mechanism of in situ surface polymerization of gallic acid in an environmental-inspired preparation of carboxylated core-shell magnetite nanoparticles.

    Science.gov (United States)

    Tóth, Ildikó Y; Szekeres, Márta; Turcu, Rodica; Sáringer, Szilárd; Illés, Erzsébet; Nesztor, Dániel; Tombácz, Etelka

    2014-12-30

    Magnetite nanoparticles (MNPs) with biocompatible coatings are good candidates for MRI (magnetic resonance imaging) contrasting, magnetic hyperthermia treatments, and drug delivery systems. The spontaneous surface induced polymerization of dissolved organic matter on environmental mineral particles inspired us to prepare carboxylated core-shell MNPs by using a ubiquitous polyphenolic precursor. Through the adsorption and in situ surface polymerization of gallic acid (GA), a polygallate (PGA) coating is formed on the nanoparticles (PGA@MNP) with possible antioxidant capacity. The present work explores the mechanism of polymerization with the help of potentiometric acid-base titration, dynamic light scattering (for particle size and zeta potential determination), UV-vis (UV-visible light spectroscopy), FTIR-ATR (Fourier-transformed infrared spectroscopy by attenuated total reflection), and XPS (X-ray photoelectron spectroscopy) techniques. We observed the formation of ester and ether linkages between gallate monomers both in solution and in the adsorbed state. Higher polymers were formed in the course of several weeks both on the surface of nanoparticles and in the dispersion medium. The ratio of the absorbances of PGA supernatants at 400 and 600 nm (i.e., the E4/E6 ratio commonly used to characterize the degree of polymerization of humic materials) was determined to be 4.3, similar to that of humic acids. Combined XPS, dynamic light scattering, and FTIR-ATR results revealed that, prior to polymerization, the GA monomers became oxidized to poly(carboxylic acid)s due to ring opening while Fe(3+) ions reduced to Fe(2+). Our published results on the colloidal and chemical stability of PGA@MNPs are referenced thoroughly in the present work. Detailed studies on biocompatibility, antioxidant property, and biomedical applicability of the particles will be published.

  20. In situ fabrication of silver nanoparticle-filled hydrogen titanate nanotube layer on metallic titanium surface for bacteriostatic and biocompatible implantation

    Science.gov (United States)

    Wang, Zheng; Sun, Yan; Wang, Dongzhou; Liu, Hong; Boughton, Robert I

    2013-01-01

    A silver nanoparticle (AgNP)-filled hydrogen titanate nanotube layer was synthesized in situ on a metallic titanium substrate. In the synthesis approach, a layer of sodium titanate nanotubes is first prepared on the titanium surface by using a hydrothermal method. Silver nitrate solution is absorbed into the nanotube channels by immersing a dried nanotube layer in silver nitrate solution. Finally, silver ions are reduced by glucose, leading to the in situ growth of AgNPs in the hydrogen titanate nanotube channels. Long-term silver release and bactericidal experiments demonstrated that the effective silver release and effective antibacterial period of the titanium foil with a AgNP-filled hydrogen titanate nanotube layer on the surface can extend to more than 15 days. This steady and prolonged release characteristic is helpful to promote a long-lasting antibacterial capability for the prevention of severe infection after surgery. A series of antimicrobial and biocompatible tests have shown that the sandwich nanostructure with a low level of silver loading exhibits a bacteriostatic rate as high as 99.99%, while retaining low toxicity for cells and possessing high osteogenic potential. Titanium foil with a AgNP-filled hydrogen titanate nanotube layer on the surface that is fabricated with low-cost surface modification methods is a promising implantable material that will find applications in artificial bones, joints, and dental implants. PMID:23966780

  1. In situ remediation-released zero-valent iron nanoparticles impair soil ecosystems health: A C. elegans biomarker-based risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying-Fei; Cheng, Yi-Hsien; Liao, Chung-Min, E-mail: cmliao@ntu.edu.tw

    2016-11-05

    Highlights: • Fe{sup 0} NPs induced infertility risk in C. elegans. • A C.elegans-based probabilistic risk assessment model is developed. • In situ remediation-released Fe{sup 0} NPs impair soil ecosystems health. - Abstract: There is considerable concern over the potential ecotoxicity to soil ecosystems posed by zero-valent iron nanoparticles (Fe{sup 0} NPs) released from in situ environmental remediation. However, a lack of quantitative risk assessment has hampered the development of appropriate testing methods used in environmental applications. Here we present a novel, empirical approach to assess Fe{sup 0} NPs-associated soil ecosystems health risk using the nematode Caenorhabditis elegans as a model organism. A Hill-based dose-response model describing the concentration–fertility inhibition relationships was constructed. A Weibull model was used to estimate thresholds as a guideline to protect C. elegans from infertility when exposed to waterborne or foodborne Fe{sup 0} NPs. Finally, the risk metrics, exceedance risk (ER) and risk quotient (RQ) of Fe{sup 0} NPs in various depths and distances from remediation sites can then be predicted. We showed that under 50% risk probability (ER = 0.5), upper soil layer had the highest infertility risk (95% confidence interval: 13.18–57.40%). The margins of safety and acceptable criteria for soil ecosystems health for using Fe{sup 0} NPs in field scale applications were also recommended. Results showed that RQs are larger than 1 in all soil layers when setting a stricter threshold of ∼1.02 mg L{sup −1} of Fe{sup 0} NPs. This C. elegans biomarker-based risk model affords new insights into the links between widespread use of Fe{sup 0} NPs and environmental risk assessment and offers potential environmental implications of metal-based NPs for in situ remediation.

  2. In situ synthesis of silver nanoparticles on the cotton fabrics modified by plasma induced vapor phase graft polymerization of acrylic acid for durable multifunction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.X., E-mail: cxwang@mail.dhu.edu.cn [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu, 224003 (China); Collaborative Innovation Center for Ecological Building, Materials and Environmental Protection Equipments, Jiangsu, 224051 (China); Laboratory for Advanced Technology in Environmental Protection, Jiangsu, 224051 (China); School of Textile and Clothing, Nantong University, Jiangsu, 226019 (China); Ren, Y. [School of Textile and Clothing, Nantong University, Jiangsu, 226019 (China); Lv, J.C.; Zhou, Q.Q.; Ma, Z.P.; Qi, Z.M.; Chen, J.Y.; Liu, G.L.; Gao, D.W. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu, 224003 (China); Lu, Z.Q. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu, 224003 (China); Collaborative Innovation Center for Ecological Building, Materials and Environmental Protection Equipments, Jiangsu, 224051 (China); Laboratory for Advanced Technology in Environmental Protection, Jiangsu, 224051 (China); Zhang, W. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu, 224003 (China); Jin, L.M. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204 (China)

    2017-02-28

    Highlights: • A new means for multifunctional cotton fabrics by PIVPGP of AA and AgNPs synthesis. • Surface modification by PIVPGP of AA had a positive effect on AgNPs loading. • Antibacterial, self-cleaning and thermal stability were greatly improved. • AgNP loaded cotton fabric exhibited excellent laundering durability. • Mechanism of AgNPs in situ synthesis on cotton fabrics by PIVPGP of AA was proposed. - Abstract: A practical and ecological method for preparing the multifunctional cotton fabrics with excellent laundering durability was explored. Cotton fabrics were modified by plasma induced vapor phase graft polymerization (PIVPGP) of acrylic acid (AA) and subsequently silver nanoparticles (AgNPs) were in situ synthesized on the treated cotton fabrics. The AgNP loaded cotton fabrics were characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), antibacterial activity, self-cleaning activity, thermal stability and laundering durability, respectively. SEM observation and EDX, XPS and XRD analysis demonstrated the much more AgNPs deposition on the cotton fabrics modified by PIVPGP of AA. The AgNP loaded cotton fabrics also exhibited better antibacterial activity, self-cleaning activity, thermal stability and laundering durability. It was concluded that the surface modification of the cotton fabrics by PIVPGP of AA could increase the loading efficiency and binding fastness of AgNPs on the treated cotton fabrics, which could fabricate the cotton fabrics with durable multifunction. In addition, the mechanism of in situ synthesis of AgNPs on the cotton fabrics modified by PIVPGP of AA was proposed.

  3. Fluorescence In Situ Hybridization for MDM2 Amplification as a Routine Ancillary Diagnostic Tool for Suspected Well-Differentiated and Dedifferentiated Liposarcomas: Experience at a Tertiary Center

    Directory of Open Access Journals (Sweden)

    Khin Thway

    2015-01-01

    Full Text Available Background. The assessment of MDM2 gene amplification by fluorescence in situ hybridization (FISH has become a routine ancillary tool for diagnosing atypical lipomatous tumor (ALT/well-differentiated liposarcoma and dedifferentiated liposarcoma (WDL/DDL in specialist sarcoma units. We describe our experience of its utility at our tertiary institute. Methods. All routine histology samples in which MDM2 amplification was assessed with FISH over a 2-year period were included, and FISH results were correlated with clinical and histologic findings. Results. 365 samples from 347 patients had FISH for MDM2 gene amplification. 170 were positive (i.e., showed MDM2 gene amplification, 192 were negative, and 3 were technically unsatisfactory. There were 122 histologically benign cases showing a histology:FISH concordance rate of 92.6%, 142 WDL/DDL (concordance 96.5%, and 34 cases histologically equivocal for WDL (concordance 50%. Of 64 spindle cell/pleomorphic neoplasms (in which DDL was a differential diagnosis, 21.9% showed MDM2 amplification. Of the cases with discrepant histology and FISH, all but 3 had diagnoses amended following FISH results. For discrepancies of benign histology but positive FISH, lesions were on average larger, more frequently in “classical” (intra-abdominal or inguinal sites for WDL/DDL and more frequently core biopsies. Discrepancies of malignant histology but negative FISH were smaller, less frequently in “classical” sites but again more frequently core biopsies. Conclusions. FISH has a high correlation rate with histology for cases with firm histologic diagnoses of lipoma or WDL/DDL. It is a useful ancillary diagnostic tool in histologically equivocal cases, particularly in WDL lacking significant histologic atypia or DDL without corresponding WDL component, especially in larger tumors, those from intra-abdominal or inguinal sites or core biopsies. There is a significant group of well-differentiated adipocytic neoplasms

  4. Development of methodology for alternative testing strategies for the assessment of the toxicological profile of nanoparticles used in medical diagnostics. NanoTEST - EC FP7 project

    International Nuclear Information System (INIS)

    Dusinska, Maria; Fjellsbo, Lise Maria; Heimstad, Eldbjorg; Harju, Mikael; Bartonova, Alena; Tran, Lang; Juillerat-Jeanneret, Lucienne; Halamoda, Blanka; Marano, Francelyne; Boland, Sonja; Saunders, Margaret; Cartwright, Laura; Carreira, Sara; Thawley, Susan; Whelan, Maurice; Klein, Christoph; Housiadas, Christos; Volkovova, Katarina; Tulinska, Jana; Beno, Milan

    2009-01-01

    Nanoparticles (NPs) have unique, potentially beneficial properties, but their possible impact on human health is still not known. The area of nanomedicine brings humans into direct contact with NPs and it is essential for both public confidence and the nanotech companies that appropriate risk assessments are undertaken in relation to health and safety. There is a pressing need to understand how engineered NPs can interact with the human body following exposure. The FP7 project NanoTEST (www.nanotest-fp7.eu) addresses these requirements in relation to the toxicological profile of NPs used in medical diagnostics.

  5. In-situ synthesis of interconnected SWCNT/OMC framework on silicon nanoparticles for high performance lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Weiwei Li

    2016-04-01

    Full Text Available In spite of silicon has a superior theoretical capacity, the large volume expansion of Si anodes during Li+ insertion/extraction is the bottle neck that results in fast capacity fading and poor cycling performance. In this paper, we report a silicon, single-walled carbon nanotube, and ordered mesoporous carbon nanocomposite synthesized by an evaporation-induced self-assembly process, in which silicon nanoparticles and single-walled carbon nanotubes were added into the phenolic resol with F-127 for co-condensation. The ordered mesoporous carbon matrix and single-walled carbon nanotubes network could effectively accommodate the volume change of silicon nanoparticles, and the ordered mesoporous structure could also provide efficient channels for the fast transport of Li-ions. As a consequence, this hybrid material exhibits a reversible capacity of 861 mAh g−1 after 150 cycles at a current density of 400 mA g−1. It achieves significant improvement in the electrochemical performance when compared with the raw materials and Si nanoparticle anodes. Keywords: Silicon, Single-walled carbon nanotube, Ordered mesoporous carbon, Lithium ion battery

  6. Finite element analysis of in-situ alignment of nanoparticles in polymeric nanofibers using magnetic field assisted electrospinning

    International Nuclear Information System (INIS)

    Jayaseelan, D; Biji, P

    2015-01-01

    In this study, a three-dimensional magnetic field assisted electrospinning (MFAES) system has been modeled to understand the correlation between the applied magnetic field and electric field distributions during nanoparticle alignment. The results reveal that the electric field distribution has been altered by positioning the magnets at the needle end. The analysis explored the possibility to create a stable liquid jet under a magnetic field, which allows the formation of organized nanostructures in nanofibers. The polarity of the magnet has been used to manipulate the electric field distribution in the electrospinning system. Based on the configuration of magnetic flux lines, the distribution of the electric field has been found to be altered. An axial magnetic field has been provided by the repulsive mode configuration, which could be the reason for alignment of nanoparticles during electrospinning. Simulation proved that the bending instability of the charged liquid jet can be efficiently controlled by placing the magnets on both sides of the fiber formation path in the electrospinning system. The impact of an axial magnetic field on nanofiber formation and nanoparticle alignment during the MFAES process was further experimentally validated. (paper)

  7. Improved accuracy in diagnostic immunohistochemistry, lectin histochemistry and in situ hybridization using a gold-labeled horseradish peroxidase antibody and silver intensification.

    Science.gov (United States)

    Roth, J; Saremaslani, P; Warhol, M J; Heitz, P U

    1992-08-01

    Improvements in the use of the avidin-biotin peroxidase complex technique and direct as well as indirect labeled avidin-biotin methods for application in diagnostic immunohistochemistry, lectin histochemistry and in situ hybridization are reported. The new technology combines the advantages of immunoenzyme and immunogold silver staining techniques and can be performed on routinely fixed and paraffin-embedded tissues. The basic modification of the labeling procedures was introduced at the final revealing step. The histochemical visualization of catalytic activity of horseradish peroxidase by the diaminobenzidine reaction was replaced by the detection of horseradish peroxidase immunoreactivity using anti-horseradish peroxidase-gold complexes and their intensification with silver acetate which is relatively light insensitive. The use of gold-labeled anti-horseradish peroxidase antibodies eliminates the need for quenching of endogenous peroxidase activity. Furthermore, the immunogold silver staining provides improved lateral resolution, higher contrast, and lower background staining as compared with the diaminobenzidine reaction. The new technology has been applied for the localization of different polypeptides in endocrine cells, cytoskeletal elements, cell surface receptors, basal lamina type IV collagen, endothelial cell marker, lectin binding sites, and DNA of various viruses. We concluded that the anti-horseradish peroxidase-gold complex is of general use in a variety of techniques applying horseradish peroxidase as a marker and should be a valuable alternative to existing enzyme substrate techniques.

  8. Watching Nanoparticles Form: An In Situ (Small-/Wide-Angle X-ray Scattering/Total Scattering) Study of the Growth of Yttria-Stabilised Zirconia in Supercritical Fluids

    DEFF Research Database (Denmark)

    Tyrsted, Christoffer; Pauw, Brian; Jensen, Kirsten Marie Ørnsbjerg

    2012-01-01

    Understanding nanoparticle formation reactions requires multitechnique in situ characterisation, since no single characterisation technique provides adequate information. Here, the first combined small-angle X-ray scattering (SAXS)/wide-angle X-ray scattering (WAXS)/total-scattering study of nano...... of nanoparticle formation is presented. We report on the formation and growth of yttria-stabilised zirconia (YSZ) under the extreme conditions of supercritical methanol for particles with Y2O3 equivalent molar fractions of 0, 4, 8, 12 and 25%....

  9. Indocyanine green-encapsulating calcium phosphosilicate nanoparticles: Bifunctional theranostic vectors for near infrared diagnostic imaging and photodynamic therapy

    Science.gov (United States)

    Altinoglu, Erhan I.

    The synthesis, laundering, and properties of calcium phosphosilicate nanoparticles (CPSNPs) that encapsulate the NIR fluorophore indocyanine green (ICG) related to multifunctional fluorescent photosensitization is presented. Imaging with transmission electron microscopy (TEM) revealed the well dispersed state of the nanoparticles, the spherical morphology, and the log normal mean particle diameter of 16 nm. Electron energy loss spectroscopy (EELS) mapping identified a Ca:P:Si ratio of 1:1.72:0.41 and a homogeneous composition without evidence of an element rich or deficient architecture. Zeta potential of the as-synthesized, citrate-functionalized CPSNPs was -29 +/-3 mV. A theoretical solids loading of 1.9 x 1013 CPSNP/mL was calculated for a standard suspension. The mean ICG content per suspension is 2 x 10 -6 M, which equates to approximately 63 fluorophore molecules encapsulated per CPSNP. For imaging and diagnostic considerations, the doped CPSNPs exhibited significantly greater intensity at the maximum emission wavelength relative to the free constituent fluorophore. The quantum efficiency of the fluorescent agent is 200% greater at 0.053+/-0.003 over the free fluorophore in PBS. Also, photostability based on fluorescence half-life of encapsulated ICG in PBS is 500% longer under typical clinical imaging conditions relative to the free dye. These performance enhancements are attributed to the matrix shielding effect of the NP around the internalized fluorophore molecules. The in vivo emission signal stability from ICG-CPSNPs was compared to the free fluorophore by whole animal NIR imaging. The duration of fluorescent signal from the ICG-CPSPNPs was extended to up to four days post-injection, highlighting the potential for long-term imaging and sensitive tracking applications using ICG when encapsulated within the protective matrix of CPSNPs. The surfaces of the ICG-CPSNPs were covalently bound with polyethylene glycol (PEG). The pharmacokinetic behavior of the

  10. Poly-thiosemicarbazide/gold nanoparticles catalytic membrane: In-situ growth of well-dispersed, uniform and stable gold nanoparticles in a polymeric membrane

    KAUST Repository

    Villalobos, Luis Francisco

    2014-11-01

    This work presents a method that achieves the highest loading, published so far, of non-agglomerated and well-distributed gold nanoparticles (AuNPs) inside a polymeric membrane. The method uses poly-thiosemicarbazide (PTSC) as the starting material for fabricating the membranes. This polymer contains one chelate site per monomeric unit, resulting in a high content of adsorption sites. This helps to achieve such high loading without agglomeration, along with the strong interaction of the chelate sites with the metal ions and the fact that they are distributed homogeneously along the membrane structure. The simple and scalable three-step procedure developed in this work resulted in a PTSC membrane containing 33.5 wt.% Au/PTSC in the form of 2.9 nm AuNPs. The membrane demonstrated catalytic activity for the reduction of 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP). © 2013 Elsevier B.V.

  11. In Situ AFM Imaging of Microstructural Changes Associated with The Spin Transition in [Fe(Htrz)₂(Trz)](Bf₄) Nanoparticles.

    Science.gov (United States)

    Manrique-Juárez, María D; Suleimanov, Iurii; Hernández, Edna M; Salmon, Lionel; Molnár, Gábor; Bousseksou, Azzedine

    2016-06-30

    Topographic images of [Fe(Htrz)₂(trz)](BF₄) nanoparticles were acquired across the first-order spin transition using variable-temperature atomic force microscopy (AFM) in amplitude modulation mode. These studies revealed a complex morphology of the particles consisting of aggregates of small nanocrystals, which expand, separate and re-aggregate due to the mechanical stress during the spin-state switching events. Both reversible (prompt or slow recovery) and irreversible effects (fatigue) on the particle morphology were evidenced and correlated with the spin crossover properties.

  12. In situ remediation-released zero-valent iron nanoparticles impair soil ecosystems health: A C. elegans biomarker-based risk assessment.

    Science.gov (United States)

    Yang, Ying-Fei; Cheng, Yi-Hsien; Liao, Chung-Min

    2016-11-05

    There is considerable concern over the potential ecotoxicity to soil ecosystems posed by zero-valent iron nanoparticles (Fe(0) NPs) released from in situ environmental remediation. However, a lack of quantitative risk assessment has hampered the development of appropriate testing methods used in environmental applications. Here we present a novel, empirical approach to assess Fe(0) NPs-associated soil ecosystems health risk using the nematode Caenorhabditis elegans as a model organism. A Hill-based dose-response model describing the concentration-fertility inhibition relationships was constructed. A Weibull model was used to estimate thresholds as a guideline to protect C. elegans from infertility when exposed to waterborne or foodborne Fe(0) NPs. Finally, the risk metrics, exceedance risk (ER) and risk quotient (RQ) of Fe(0) NPs in various depths and distances from remediation sites can then be predicted. We showed that under 50% risk probability (ER=0.5), upper soil layer had the highest infertility risk (95% confidence interval: 13.18-57.40%). The margins of safety and acceptable criteria for soil ecosystems health for using Fe(0) NPs in field scale applications were also recommended. Results showed that RQs are larger than 1 in all soil layers when setting a stricter threshold of ∼1.02mgL(-1) of Fe(0) NPs. This C. elegans biomarker-based risk model affords new insights into the links between widespread use of Fe(0) NPs and environmental risk assessment and offers potential environmental implications of metal-based NPs for in situ remediation. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Direct in situ activation of Ag{sup 0} nanoparticles in synthesis of Ag/TiO{sub 2} and its photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Jaafar, N.F. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Jalil, A.A., E-mail: aishah@cheme.utm.my [Institute of Hydrogen Economy, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Efendi, J. [Department of Chemistry, Universitas Negeri Padang, Jl. Prof. Hamka, Air Tawar, Padang, West Sumatera (Indonesia); Mukti, R.R. [Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl Ganesha No. 10, Bandung 40132 (Indonesia); Jusoh, R.; Jusoh, N.W.C. [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Karim, A.H. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Salleh, N.F.M. [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Suendo, V. [Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl Ganesha No. 10, Bandung 40132 (Indonesia)

    2015-05-30

    Graphical abstract: - Highlights: • Ag{sup 0} loaded on TiO{sub 2} was prepared by a direct in situ electrochemical method. • 5 wt% Ag–TiO{sub 2} demonstrated the best photocatalytic degradation of 2-CP. • Isomorphous substitution of Ag with Ti occurred to form Ti−O−Ag bonds. • Ag{sup 0} and oxygen vacancies trapped electrons to enhance e–H{sup +} separation. • Substitution of Ag in the TiO{sub 2} structure decreased the number of oxygen vacancies. - Abstract: Metallic Ag nanoparticles (Ag{sup 0}) were successfully activated using a direct in situ electrochemical method before being supported on TiO{sub 2}. Catalytic testing showed that 5 wt% Ag–TiO{sub 2} gave the highest photodegradation (94%) of 50 mg L{sup −1} 2-chlorophenol (2-CP) at pH 5 using 0.375 g L{sup −1} catalyst within 6 h, while under similar conditions, 1 wt% and 10 wt% Ag–TiO{sub 2} only gave 75% and 78% degradation, respectively. Characterization results illustrated that the photoactivity was affected by the amount of Ag{sup 0} and oxygen vacancies which act as an electrons trap to enhance the electron–hole separation. While, the Ag−O−Ti bonds formation reduced the photoactivity. The degradation followed a pseudo-first order Langmuir–Hinshelwood model where adsorption was the controlling step. Study on the effect of scavengers showed that the hole (H{sup +}) and hydroxyl radical (OH·) play important roles in the photodegradation. The regenerated photocatalyst was still stable after five cycling runs.

  14. The evaluation of a rapid in situ HIV confirmation test in a programme with a high failure rate of the WHO HIV two-test diagnostic algorithm.

    Directory of Open Access Journals (Sweden)

    Derryck B Klarkowski

    Full Text Available BACKGROUND: Concerns about false-positive HIV results led to a review of testing procedures used in a Médecins Sans Frontières (MSF HIV programme in Bukavu, eastern Democratic Republic of Congo. In addition to the WHO HIV rapid diagnostic test algorithm (RDT (two positive RDTs alone for HIV diagnosis used in voluntary counselling and testing (VCT sites we evaluated in situ a practical field-based confirmation test against western blot WB. In addition, we aimed to determine the false-positive rate of the WHO two-test algorithm compared with our adapted protocol including confirmation testing, and whether weakly reactive compared with strongly reactive rapid test results were more likely to be false positives. METHODOLOGY/PRINCIPAL FINDINGS: 2864 clients presenting to MSF VCT centres in Bukavu during January to May 2006 were tested using Determine HIV-1/2 and UniGold HIV rapid tests in parallel by nurse counsellors. Plasma samples on 229 clients confirmed as double RDT positive by laboratory retesting were further tested using both WB and the Orgenics Immunocomb Combfirm HIV confirmation test (OIC-HIV. Of these, 24 samples were negative or indeterminate by WB representing a false-positive rate of the WHO two-test algorithm of 10.5% (95%CI 6.6-15.2. 17 of the 229 samples were weakly positive on rapid testing and all were negative or indeterminate by WB. The false-positive rate fell to 3.3% (95%CI 1.3-6.7 when only strong-positive rapid test results were considered. Agreement between OIC-HIV and WB was 99.1% (95%CI 96.9-99.9% with no false OIC-HIV positives if stringent criteria for positive OIC-HIV diagnoses were used. CONCLUSIONS: The WHO HIV two-test diagnostic algorithm produced an unacceptably high level of false-positive diagnoses in our setting, especially if results were weakly positive. The most probable causes of the false-positive results were serological cross-reactivity or non-specific immune reactivity. Our findings show that the OIC

  15. Temperature, pressure, and size dependence of Pd-H interaction in size selected Pd-Ag and Pd-Cu alloy nanoparticles: In-situ X-ray diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Sengar, Saurabh K.; Mehta, B. R., E-mail: brmehta@physics.iitd.ac.in [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India); Kulriya, P. K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2014-03-21

    In this study, in-situ X-ray diffraction has been carried out to investigate the effect of temperature and pressure on hydrogen induced lattice parameter variation in size selected Pd-Ag and Pd-Cu alloy nanoparticles. The nanoparticles of three different mobility equivalent diameters (20, 40, and 60 nm) having a narrow size distribution were prepared by gas phase synthesis method. In the present range of temperature (350 K to 250 K) and pressure (10{sup −4} to 100 millibars), no α (H/Pd ≤ 0.03) ↔ β (H/Pd ≥ 0.54) phase transition is observed. At temperature higher than 300 °C or pressure lower than 25 millibars, there is a large difference in the rate at which lattice constant varies as a function of pressure and temperature. Further, the lattice variation with temperature and pressure is also observed to depend upon the nanoparticle size. At lower temperature or higher pressure, size of the nanoparticle seems to be relatively less important. These results are explained on the basis of the relative dominance of physical absorption and diffusion of H in Pd alloy nanoparticles at different temperature and pressure. In the present study, absence of α ↔ β phase transition points towards the advantage of using Pd-alloy nanoparticles in applications requiring long term and repeated hydrogen cycling.

  16. Asphaltene adsorption onto acidic/basic metal oxide nanoparticles toward in situ upgrading of reservoir oils by nanotechnology.

    Science.gov (United States)

    Hosseinpour, Negahdar; Khodadadi, Abbas Ali; Bahramian, Alireza; Mortazavi, Yadollah

    2013-11-19

    The effects of surface acidity and basicity of metal oxide nanoparticles on the thermodynamics of asphaltene adsorption were studied. Three different categories of metal oxides/salts with acidic (WO3 and NiO), amphoteric (Fe2O3 and ZrO2), and basic (MgO and CaCO3) surfaces were synthesized, and their textural, structural, and acid-base properties were characterized. Asphaltenes were extracted from a dead oil sample and characterized by X-ray powder diffraction and Fourier transform infrared spectroscopy. The acid and base numbers of the asphaltenes were measured. The nanoparticles were added to the asphaltene-toluene solutions, and the amount of adsorbed asphaltene was obtained through centrifugation followed by UV-vis spectroscopy of the supernatant liquid and temperature-programmed oxidation analysis of the precipitated solid. The concentrations of organic acid and base groups in the asphaltenes are 2.75 and 12.34 mg of KOH/g, respectively, indicating that the asphaltenes are more basic in nature. Isotherms of the asphaltene adsorption onto the six metal oxides/salts fit the Langmuir model closely. The asphaltene adsorption capacity of the nanoparticles is 1.23-3.67 mg/m(2) and decreases in the order of NiO > Fe2O3 > WO3 > MgO > CaCO3 > ZrO2, concomitant with the synergetic effects of acidity and the net charge of the surfaces. High-resolution transmission electron microscopy illustrates that the asphaltenes are spread out over the surfaces with no short-range/long-range order. The adsorption of the asphaltenes onto the six samples is exothermic and spontaneous with the Gibbs energy change of -27.80 to -28.79 kJ/mol at 25 °C. The absolute value of the enthalpy change of the adsorption is calculated to be within the range of 5-20 kJ/mol. Acid-base interaction and electrostatic attraction seem to be the dominant forces contributing to the adsorption of the asphaltenes onto the metal oxide/salt surfaces.

  17. Nanocomposite hydrogels stabilized by self-assembled multivalent bisphosphonate-magnesium nanoparticles mediate sustained release of magnesium ion and promote in-situ bone regeneration.

    Science.gov (United States)

    Zhang, Kunyu; Lin, Sien; Feng, Qian; Dong, Chaoqun; Yang, Yanhua; Li, Gang; Bian, Liming

    2017-12-01

    Hydrogels are appealing biomaterials for applications in regenerative medicine due to their tunable physical and bioactive properties. Meanwhile, therapeutic metal ions, such as magnesium ion (Mg 2+ ), not only regulate the cellular behaviors but also stimulate local bone formation and healing. However, the effective delivery and tailored release of Mg 2+ remains a challenge, with few reports on hydrogels being used for Mg 2+ delivery. Bisphosphonate exhibits a variety of specific bioactivities and excellent binding affinity to multivalent cations such as Mg 2+ . Herein, we describe a nanocomposite hydrogel based on hyaluronic acid and self-assembled bisphosphonate-magnesium (BP-Mg) nanoparticles. These nanoparticles bearing acrylate groups on the surface not only function as effective multivalent crosslinkers to strengthen the hydrogel network structure, but also promote the mineralization of hydrogels and mediate sustained release of Mg 2+ . The released Mg 2+ ions facilitate stem cell adhesion and spreading on the hydrogel substrates in the absence of cell adhesion ligands, and promote osteogenesis of the seeded hMSCs in vitro. Furthermore, the acellular porous hydrogels alone can support in situ bone regeneration without using exogenous cells and inductive agents, thereby greatly simplifying the approaches of bone regeneration therapy. In this study, we developed a novel bioactive nanocomposite hydrogel based on hyaluronic acid and self-assembled bisphosphonate-magnesium (BP-Mg) nanoparticles. Such hydrogels are stabilized by the multivalent crosslinking domains formed by the aggregation of Ac-BP-Mg NPs, and therefore show enhanced mechanical properties, improved capacity for mineralization, and controlled release kinetics of Mg 2+ . Moreover, the released Mg 2+ can enhance cell adhesion and spreading, and further promote the osteogenic differentiation of hMSCs. Owing to these unique properties, these acellular hydrogels alone can well facilitate the in vivo

  18. Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles

    Science.gov (United States)

    Kumar, Nirmal; Biswas, Krishanu

    2015-08-01

    The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

  19. Demonstration of multi-generational growth of tungsten nanoparticles in hydrogen plasma using in situ laser extinction method

    Science.gov (United States)

    Ouaras, K.; Lombardi, G.; Hassouni, K.

    2018-03-01

    For the first time, we demonstrate that tungsten (W) nanoparticles (NPs) are created when a tungsten target is exposed to low-pressure, high density hydrogen plasma. The plasma was generated using a novel dual plasma system combining a microwave discharge and a pulsed direct-current (DC) discharge. The tungsten surface originates in the multi-generational formation of a significant population of 30-70 nm diameter particles when the W cathode is biased at ~  -1 kV and submitted to ~1020 m2 s-1 H+/H2+ /H3+ ions flux. The evidenced NPs formation should be taking into account as one of the consequence of the plasma surface interaction outcomes, especially for fusion applications.

  20. In-situ electrochemical coating of Ag nanoparticles onto graphite electrode with enhanced performance for Li-ion batteries

    International Nuclear Information System (INIS)

    Yun, Jiaojiao; Wang, Yan; Gao, Tian; Zheng, Huiyuan; Shen, Ming; Qu, Qunting; Zheng, Honghe

    2015-01-01

    The effects of silver hexafluorophosphate (AgPF 6 ) as an electrolyte additive on the electrochemical behaviors of graphite anode are systematically studied by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The surface structure and composition of graphite electrode after electrochemical cycles are investigated through scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. It is found that Ag nanoparticles derived from electrochemical reduction of Ag + are homogenously distributed on the graphite surface. Significant improvements on the discharge capacity, rate behavior, and low-temperature performance of graphite electrode are obtained. The reasons are associated with the decreased resistances of solid-electrolyte interface and charge-transfer process, which improve the electrode kinetics for Li + intercalation/deintercalation

  1. A bench-top K X-ray fluorescence system for quantitative measurement of gold nanoparticles for biological sample diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, K., E-mail: k.ricketts@ucl.ac.uk [Division of Surgery and Interventional Sciences, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF (United Kingdom); Guazzoni, C.; Castoldi, A. [Dipartimento di Elettronica, Informazione e Bioingegneria Politecnico di Milano and INFN, Sezione di Milano P.za Leonardo da Vinci, 32-20133 Milano (Italy); Royle, G. [Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London WC1E 6BT (United Kingdom)

    2016-04-21

    Gold nanoparticles can be targeted to biomarkers to give functional information on a range of tumour characteristics. X-ray fluorescence (XRF) techniques offer potential quantitative measurement of the distribution of such heavy metal nanoparticles. Biologists are developing 3D tissue engineered cellular models on the centimetre scale to optimise targeting techniques of nanoparticles to a range of tumour characteristics. Here we present a high energy bench-top K-X-ray fluorescence system designed for sensitivity to bulk measurement of gold nanoparticle concentration for intended use in such thick biological samples. Previous work has demonstrated use of a L-XRF system in measuring gold concentrations but being a low energy technique it is restricted to thin samples or superficial tumours. The presented system comprised a high purity germanium detector and filtered tungsten X-ray source, capable of quantitative measurement of gold nanoparticle concentration of thicker samples. The developed system achieved a measured detection limit of between 0.2 and 0.6 mgAu/ml, meeting specifications of biologists and being approximately one order of magnitude better than the detection limit of alternative K-XRF nanoparticle detection techniques. The scatter-corrected K-XRF signal of gold was linear with GNP concentrations down to the detection limit, thus demonstrating potential in GNP concentration quantification. The K-XRF system demonstrated between 5 and 9 times less sensitivity than a previous L-XRF bench-top system, due to a fundamental limitation of lower photoelectric interaction probabilities at higher K-edge energies. Importantly, the K-XRF technique is however less affected by overlying thickness, and so offers future potential in interrogating thick biological samples.

  2. In Situ Wrapping Si Nanoparticles with 2D Carbon Nanosheets as High-Areal-Capacity Anode for Lithium-Ion Batteries.

    Science.gov (United States)

    Yan, Lijing; Liu, Jie; Wang, Qianqian; Sun, Minghao; Jiang, Zhanguo; Liang, Chengdu; Pan, Feng; Lin, Zhan

    2017-11-08

    Silicon (Si) has aroused great interest as the most attractive anode candidate for energy-dense lithium-ion batteries (LIBs) in the past decade because of its significantly high capacity and low discharge potential. However, the large volume change during cycling impedes its practical application, which is more serious in the case of high mass loading. Designing Si anode with high mass loading and high areal capacity by a simple, scalable, and environmentally friendly method is still a big challenge. Herein, we report in situ one-pot synthesis of Si/C composite, where Si nanoparticles are wrapped by graphene-like 2D carbon nanosheets. After 500 cycles at 420 mA g -1 , the Si/C anode displays a gravimetric capacity of 881 mAh g -1 with 86.4% capacity being retained. More specially, a high areal capacity of 3.13 mAh cm -2 at 5.00 mg cm -2 after 100 cycles is achieved. This study demonstrates a novel route for the preparation of the Si/C composite with high material utilization and may expand the possibility of future design Si-based anode with high areal capacity for high energy LIBs.

  3. Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

    Science.gov (United States)

    Schilz, Jodi R.; Reddy, K. J.; Nair, Sreejayan; Johnson, Thomas E.; Tjalkens, Ronald B.; Krueger, Kem P.; Clark, Suzanne

    2015-01-01

    In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted through ion exchange. The resultant production bleed water (PBW) contains contaminants such as arsenic and other heavy metals. Samples of PBW from an active ISR uranium facility were treated with cupric oxide nanoparticles (CuO-NPs). CuO-NP treatment of PBW reduced priority contaminants, including arsenic, selenium, uranium, and vanadium. Untreated and CuO-NP treated PBW was used as the liquid component of the cell growth media and changes in viability were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human embryonic kidney (HEK 293) and human hepatocellular carcinoma (Hep G2) cells. CuO-NP treatment was associated with improved HEK and HEP cell viability. Limitations of this method include dilution of the PBW by growth media components and during osmolality adjustment as well as necessary pH adjustment. This method is limited in its wider context due to dilution effects and changes in the pH of the PBW which is traditionally slightly acidic however; this method could have a broader use assessing CuO-NP treatment in more neutral waters. PMID:26132311

  4. In-situ one-step synthesis of carbon-encapsulated naked magnetic metal nanoparticles conducted without additional reductants and agents

    Science.gov (United States)

    Kang, Jun; Kim, Yeonwon; Kim, Hye-Min; Hu, Xiulan; Saito, Nagahiro; Choi, Jae-Hyuk; Lee, Myeong-Hoon

    2016-12-01

    C-encapsulated highly pure Ni, Co, and Fe magnetic nanoparticles (MNPs/C) were synthesized by an innovative one-step in-situ plasma in liquid method (solution plasma processing, SPP) without any additional reductants, agents, or treatment. Successful encapsulation of MNPs was demonstrated by using inductively coupled plasma-atomic emission spectrometry and cyclic voltammetry techniques. The obtained X-ray diffraction patterns and transmission electron microscopy images corresponded to MNPs with average diameters of 5 nm and good crystalline structure. The C capsules with spherical shapes (containing onion-like layers) were characterized by uniform sizes (ranging from 20 nm to 30 nm) and chain-like morphologies. The synthesized MNPs/C exhibited superparamagnetic properties at room temperature and might be utilized in data storage, biomedical, and energy applications since various NPs (including bimetallic ones) could be easily prepared by changing working electrodes. This study shows the potential of SPP to be a candidate for the next-generation synthesis method of NPs/C.

  5. Facile in Situ Synthesis of Silver Nanoparticles on the Surface of Metal-Organic Framework for Ultrasensitive Surface-Enhanced Raman Scattering Detection of Dopamine.

    Science.gov (United States)

    Jiang, Zhongwei; Gao, Pengfei; Yang, Lin; Huang, Chengzhi; Li, Yuanfang

    2015-12-15

    Surface-enhanced Raman scattering (SERS) signals are intensively dominated by the Raman hot spots and distance between analyte molecules and metallic nanostructures. Herein, an efficient SERS substrate was developed by in situ synthesis of silver nanoparticles (AgNPs) on the surface of MIL-101 (Fe), a typical metal-organic framework (MOF). The as-prepared SERS substrate combines the numerous Raman hot spots between the high-density Ag NPs and the excellent adsorption performance of MOFs, making it an excellent SERS substrate for highly sensitive SERS detection by effectively concentrating analytes in close proximity to the Raman hot spots domains between the adjacent AgNPs. The resulting hybrid material was used for ultrasensitive SERS detection of dopamine based on the peroxidase-like activity of MIL-101 (Fe) by utilizing the enzyme-linked immunosorbent assay (ELISA) colorimetric substrate, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) as a SERS marker. This new developed method showed good linearity in the range from 1.054 pM to 210.8 nM for dopamine with the correlation coefficient of 0.992, detection limit of approximately 0.32 pM [signal-to-noise ratio (S/N) = 3], and acceptable recoveries ranging from 99.8% to 108.0% in human urine. These results predict that the proposed SERS system may open up a new opportunity for chemical and biological assay applications.

  6. Simultaneous AuIII Extraction and In Situ Formation of Polymeric Membrane-Supported Au Nanoparticles: A Sustainable Process with Application in Catalysis.

    Science.gov (United States)

    Mora-Tamez, Lucía; Esquivel-Peña, Vicente; Ocampo, Ana L; Rodríguez de San Miguel, Eduardo; Grande, Daniel; de Gyves, Josefina

    2017-04-10

    A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of Au III salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for Au III extraction. The simultaneous extraction and reduction processes were proven to be the result of a synergic phenomenon in which all the membrane components were involved. Scanning electron microscopy characterization of cross-sectional samples suggested a distribution of AuNPs throughout the membrane. Transmission electron microscopy characterization of the AuNPs indicated average particle sizes of 36.7 and 2.9 nm for the PIMs and PNMs, respectively. AuNPs supported on PIMs allowed for >95.4 % reduction of a 0.05 mmol L -1 4-nitrophenol aqueous solution with 10 mmol L -1 NaBH 4 solution within 25 min. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. One-step, room temperature, colorimetric melamine sensing using an in-situ formation of silver nanoparticles through modified Tollens process

    Science.gov (United States)

    Wang, Huiying; Chen, Dinglong; Yu, Longquan; Chang, Ming; Ci, Lijie

    2015-02-01

    We have developed a rapid, sensitive, one-step, and selective colorimetric detection method for melamine (MEL) in milk powder based upon an in-situ formation of silver nanoparticles (AgNPs) through modified Tollens process at room temperature. The triazine ring N atoms of MEL molecule were strategically designed to complex the Ag+ through electron donor-acceptor interaction. During the AgNPs formation procedure, the MEL molecule, which has been covalently bonded with the Ag+ ions, was adsorbed to the surface of as-prepared AgNPs, resulting in the aggregation of the adjacent AgNPs with detectable decreases of absorption signal. The concentration of MEL can be determined with the naked eye or a UV-vis spectrometer at which the yellow-to-brown color change associated with aggregate enhancement takes place. This method enables rapid (less than 30 min) and sensitive (limit of detection, LOD, 10 nM) detection, and it was also able to discriminate MEL from sixteen other milk relevant coexisting compounds. This assay does not utilize organic cosolvents, enzymatic reactions, light-sensitive dye molecules, lengthy protocols, or sophisticated instrumentation thereby overcoming some of the limitations of conventional methods.

  8. In Situ Synthesis and Electrophoretic Deposition of NiO/Ni Core-Shell Nanoparticles and Its Application as Pseudocapacitor

    Directory of Open Access Journals (Sweden)

    Joaquin Yus

    2017-11-01

    Full Text Available A simple, low cost and transferable colloidal processing method and the subsequent heat treatment has been optimized to prepare binder-free electrodes for their application in supercapacitors. NiO/Ni core–shell hybrid nanostructures have been synthetized by heterogeneous precipitation of metallic Ni nanospheres onto NiO nanoplatelets as seed surfaces. The electrophoretic deposition (EPD has been used to shape the electroactive material onto 3D substrates such as Ni foams. The method has allowed us to control the growth and the homogeneity of the NiO/Ni coatings. The presence of metallic Nickel in the microstructure and the optimization of the thermal treatment have brought several improvements in the electrochemical response due to the connectivity of the final microstructure. The highest specific capacitance value has been obtained using a thermal treatment of 325 °C during 1 h in Argon. At this temperature, necks formed among ceramic-metallic nanoparticles preserve the structural integrity of the microstructure avoiding the employment of binders to enhance their connectivity. Thus, a compromise between porosity and connectivity should be established to improve electrochemical performance.

  9. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation

    KAUST Repository

    Ben-Sasson, Moshe

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. © 2014 Elsevier Ltd.

  10. In situ biosynthesis of ultrafine metal nanoparticles within a metal-organic framework for efficient heterogeneous catalysis

    Science.gov (United States)

    Tang, Lei; Shi, Jiafu; Wu, Hong; Zhang, Shaohua; Liu, Hua; Zou, Hongjian; Wu, Yizhou; Zhao, Jingjing; Jiang, Zhongyi

    2017-09-01

    The synthesis of ultrafine, uniform, well-dispersed functional nanoparticles (NPs) under mild conditions in a controlled manner remains a great challenge. In biological systems, a well-defined biomineralization process is exploited, in which the control over NPs’ size, shape and distribution is temporally and spatially regulated by a variety of biomolecules in a confined space. Inspired by this, we embedded proteins into metal-organic frameworks (MOFs) and explored a novel approach to synthesize metallic NPs by taking the synergy of protein-induced biomineralization process and space-confined effect of MOFs. The generation and growth of ultrafine metal NPs (Ag or Au) was induced by the entrapped lysozyme molecules and confined by the ZIF-8 pores. Due to the narrow size distribution and homogeneous spatial distribution of metal NPs, the as-synthesized NPs exhibit remarkably elevated catalytic activity. These findings demonstrate that MOFs can be loaded with specific proteins to selectively deposit inorganic NPs via biomimetic mineralization and these novel kinds of nanohybrid materials may find applications in catalysis, sensing and optics.

  11. In situ monitoring of flash-light sintering of copper nanoparticle ink for printed electronics.

    Science.gov (United States)

    Hwang, Hyun-Jun; Chung, Wan-Ho; Kim, Hak-Sung

    2012-12-07

    In this work, a flash-light sintering process for Cu nanoinks was studied. In order to precisely monitor the milliseconds flash-light sintering process, a real-time Wheatstone bridge electrical circuit and a high-rate data acquisition system were used. The effects of several flash-light irradiation conditions (irradiation energy, pulse number, on-time, and off-time) and the effects of the amount of poly(N-vinylpyrrolidone) in the Cu nanoink on the flash-light sintering process were investigated. The microstructures of the sintered Cu films were analyzed by scanning electron microscopy. To investigate the oxidation or reduction of the oxide-covered copper nanoparticles, a crystal phase analysis using x-ray diffraction was performed. In addition, the sheet resistance of Cu film was measured using a four-point probe method. From this study, it was found that the flash-light sintered Cu nanoink films have a conductivity of 72 Ωm/sq without any damage to the polyimide substrate. Similar nanoinks are expected to be widely used in printed and flexible electronics products in the near future.

  12. In Situ IR Characterization of CO Interacting with Rh Nanoparticles Obtained by Calcination and Reduction of Hydrotalcite-Type Precursors

    Directory of Open Access Journals (Sweden)

    F. Basile

    2011-01-01

    Full Text Available Supported Rh nanoparticles obtained by reduction in hydrogen of severely calcined Rh/Mg/Al hydrotalcite-type (HT phases have been characterized by FT-IR spectroscopy of adsorbed CO [both at room temperature (r.t. and nominal liquid nitrogen temperature] and Transmission Electron Microscopy (TEM. The effect of reducing temperature has been investigated, showing that Rh crystal size increases from 1.4 nm to 1.8 nm when the reduction temperature increases from 750°C to 950°C. The crystal growth favours the formation of bridged CO species and linear monocarbonyl species with respect to gem-dicarbonyl species; when CO adsorbs at r.t., CO disproportionation occurs on Rh and it accompanies the formation of RhI(CO2. The role of interlayer anions in the HT precursors to affect the properties of the final materials has been also investigated considering samples prepared from silicate-instead of carbonate-containing precursors. In this case, formation of RhI(CO2 and CO disproportionation do not occur, and this evidence is discussed in terms of support effect.

  13. Durable antimicrobial cotton textiles coated sonochemically with ZnO nanoparticles embedded in an in-situ enzymatically generated bioadhesive.

    Science.gov (United States)

    Salat, Marc; Petkova, Petya; Hoyo, Javier; Perelshtein, Ilana; Gedanken, Aharon; Tzanov, Tzanko

    2018-06-01

    An important preventive measure for providing a bacteria-free environment for the patients is the introduction of highly efficient and durable antibacterial textiles in hospitals. This work describes a single step sono-enzymatic process for coating of cotton medical textiles with antibacterial ZnO nanoparticles (NPs) and gallic acid (GA) to produce biocompatible fabrics with durable antibacterial properties. Cellulose substrates, however, need pre-activation to achieve sufficient stability of the NPs on their surface. Herein, this drawback is overcome by the simultaneous sonochemical deposition of ZnO NPs and the synthesis of a bio-based adhesive generated by the enzymatic cross-linking of GA in which the NPs were embedded. GA possesses the multiple functions of an antibacterial agent, a building block of the cross-linked phenolic network, and as a compound providing the safe contact of the coated materials with human skin. The ZnO NPs-GA coated fabrics maintained above 60% antibacterial efficacy even after 60 washing cycles at 75 °C hospital laundry regime. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Spontaneous Ag-Nanoparticle Growth at Single-Walled Carbon Nanotube Defect Sites: A Tool for In Situ Generation of SERS Substrate

    Directory of Open Access Journals (Sweden)

    Jason Maley

    2011-01-01

    Full Text Available Silver nanoparticles were spontaneously formed on pristine and oxidized single-wall nanotubes. Nanoparticles were observed on carbon nanotubes with AFM, and the presence of Ag nanoparticles were confirmed by ESR experiments. Raman spectroscopy of the Ag-treated carbon nanotubes had a 4–10X enhancement of intensity compared to untreated carbon nanotubes. Ag nanoparticles formed at defect sites on the CNT surface, where free electrons located at the defect sites reduced Ag+ to Ag. A mechanism for the propagation of the nanoparticles is through a continual negative charge generation on the nanoparticle by electron transfer from doublet oxygen (O2−.

  15. Magnetic Marking and Intraoperative Detection of Primary Draining Lymph Nodes in High-Risk Prostate Cancer Using Superparamagnetic Iron Oxide Nanoparticles: Additional Diagnostic Value

    Directory of Open Access Journals (Sweden)

    Alexander Winter

    2017-12-01

    Full Text Available Sentinel lymph node dissection (sLND using a magnetometer and superparamagnetic iron oxide nanoparticles (SPIONs as a tracer was successfully applied in prostate cancer (PCa. Radioisotope-guided sLND combined with extended pelvic LND (ePLND achieved better node removal, increasing the number of affected nodes or the detection of sentinel lymph nodes outside the established ePLND template. We determined the diagnostic value of additional magnetometer-guided sLND after intraprostatic SPION-injection in high-risk PCa. This retrospective study included 104 high-risk PCa patients (PSA >20 ng/mL and/or Gleason score ≥ 8 and/or cT2c from a prospective cohort who underwent radical prostatectomy with magnetometer-guided sLND and ePLND. The diagnostic accuracy of sLND was assessed using ePLND as a reference standard. Lymph node metastases were found in 61 of 104 patients (58.7%. sLND had a 100% diagnostic rate, 96.6% sensitivity, 95.6% specificity, 96.6% positive predictive value, 95.6% negative predictive value, 3.4% false negative rate, and 4.4% false positive rate (detecting lymph node metastases outside the ePLND template. These findings demonstrate the high sensitivity and additional diagnostic value of magnetometer-guided sLND, exceeding that of ePLND through the individualized extension of PLND or the detection of sentinel lymph nodes/lymph node metastases outside the established node template in high-risk PCa.

  16. In-situ deposition of silver-iron oxide nanoparticles on the surface of fly ash for water purification.

    Science.gov (United States)

    Joshi, Mahesh Kumar; Pant, Hem Raj; Liao, Nina; Kim, Jun Hee; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2015-09-01

    In this study, a fly ash based composite, Ag-iron oxide/fly ash, was synthesized via a facile one-pot hydrothermal process using fly ash, ferrous chloride, and silver nitrate as precursors. Field emission scanning electron microscopy (FE-SEM), EDX, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Photoluminescence (PL) and Brunauer-Emmett-Teller (BET) surface area measurement confirmed the formation of composite particle. FA provided a suitable surface for the in-situ deposition of Fe3O4 and Ag NPs during hydrothermal treatment. As a result, the particle size of Fe3O4 and Ag NPs was sufficiently decreased, and the surface area of the NPs as well as, a whole matrix was increased. The antimicrobial activity of the composite was accessed by Escherichia coli inhibition assay. Lead(II) ion adsorption efficiency of the composite was analyzed from a series of batch adsorption experiments (the effects of concentration, contact time, pH and adsorbent dose on the adsorption of Pb(II) ion from aqueous solution). Results indicated that as-synthesized composite has high antibacterial capacity, and the metal ions uptake efficiency compared to fly ash particle. Furthermore, incorporation Fe3O4 NPs onto the fly ash make it easily separable from a reaction system using an external magnet. The composite synthesis protocol is a simple method that utilizes a readily available industrial byproduct to produce a unique composite for environmental remediation. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Development of an in-situ diagnostic for the measurement of the hydrogen content of amorphous hydrocarbon layers in fusion devices; Entwicklung einer In-situ-Messmethode zur Bestimmung des Wasserstoffgehalts amorpher Kohlenwasserstoffschichten in Fusionsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Irrek, F.

    2008-07-15

    A diagnostic method, the laser-induced thermal desorption spectroscopy (LDS), is developed to measure in situ the hydrogen inventory in the surface of plasma-facing components in fusion experiments. Its capabilities will be demonstrated in TEXTOR. In LDS, during the plasma discharge a laser beam is used to heat a spot on a surface close to the plasma to a temperature of 1400 to 2100 K to a depth of 100 {mu}m. Trapped hydrogen will be released into the plasma where it emits line radiation. The emitted H{sub a}-light is quantitatively measured. The amount of released hydrogen is calculated from the intensity of this emission using conversion factors (S/XB){sub eff}. The laser light (Nd:YAG, 1064 nm) is conducted via light fibres. At TEXTOR, a 5 mm{sup 2} sized homogeneous laser spot is created with a pulse duration of 1.5 ms, and an Energy of 5 J, typically. Below the laser spot a volume of at most 1 mm{sup 3} is desorbed. The generated temperature is calculated numerically and indirectly deduced from surface changings. Depending on the conditions during the layer formation the hydrogen content of the hydrocarbon layer will vary and different fractions of the released molecules (H{sub 2}, CH{sub 4}, C{sub 2}H{sub 4}) are created during the laser heating. The release of atomic hydrogen by laser desorption was not found. The emitted light is measured by means of narrow-band interference filters and a CCD-camera. The fraction of the light emission which lies outside the observation volume is estimated using simulations of the emission by the neutral gas transport Monte Carlo code EIRENE for each molecular fraction. Conversion factors (S/XB){sub eff} were measured in various reference plasmas (T{sub e}=22-30 eV, n{sub e}=1-11 x 10{sup 18} m{sup -3} and T{sub e}=50-74 eV, n{sub e}=1-5 x 10{sup 18} m{sup -3}) by desorbing prepared graphite samples which release a known amount of hydrogen with a known molecular distribution. LDS measurements were carried out in TEXTOR at

  18. Green and Facile Synthesis of Highly Stable Gold Nanoparticles via Hyperbranched Polymer In-Situ Reduction and Their Application in Ag+ Detection and Separation

    Directory of Open Access Journals (Sweden)

    Xunyong Liu

    2018-01-01

    Full Text Available The development of a green and facile strategy for synthesizing high stable gold nanoparticles (AuNPs is still highly challenging. Additionally, the main problems regarding AuNPs based colorimetric sensors are their poor selectivity and low sensitivity, as well their tendency to aggregate during their synthesis and sensing process. Herein, we present an in-situ reduction strategy to synthesize thermoresponsive hyperbranched polymer (i.e., Hyperbranched polyethylenimine-terminal isobutyramide (HPEI-IBAm functionalized AuNPs. The HPEI-IBAm-AuNPs show excellent thermal stability up to 200 °C, high tolerance of a wide range of pH value (3–13, and high salt resistance. HPEI-IBAm acted as the template, the reducing agent, and the stabilizing agent for the preparation of AuNPs. The HPEI-IBAm-AuNPs can be used as colorimetric sensors for the detection of Ag+. In the detecting process, HPEI-IBAm serves as a trigger agent to cause an unusual color change from red to brown. This new non-aggregation-based colorimetric sensor showed high stability (maintaining the color lasting without fading, high selectivity, and high sensitivity with an extremely low detection limit of 7.22 nM and a good linear relationship in a wide concentration range of 0–2.0 mM (R2 = 0.9921. Significantly, based on the thermoresponsive property of the HPEI-IBAm, the AuNPs/Ag composites can be separated after sensing detection, which can avoid secondary pollutions. Therefore, the green preparation and the applications of the unusual colorimetric sensor truly embody the concepts of energy saving, environmental protection, and sustainable development.

  19. In situ electrochemical synthesis of highly loaded zirconium nanoparticles decorated reduced graphene oxide for the selective determination of dopamine and paracetamol in presence of ascorbic acid.

    Science.gov (United States)

    Ezhil Vilian, A T; Rajkumar, Muniyandi; Chen, Shen-Ming

    2014-03-01

    Highly loaded zirconium oxide (ZrO2) nanoparticles were supported on graphene oxide (ERGO/ZrO2) via an in situ, simple and clean strategy on the basis of the electrochemical redox reaction between zirconyl chloride and graphene oxide (ZrOCl2 and GO). The electrochemical measurements and surface morphology of the as prepared nanocomposite were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FESEM). This ZrO2 decorated reduced graphene oxide nanocomposite modified GCE (ERGO/ZrO2) exhibits a prominent electrocatalytic activity toward the selective detection and determination of dopamine (DA) and paracetamol (PA) in presence of ascorbic acid (AA). The peaks of linear sweep voltammetry (LSV) for DA and PA oxidation at ERGO/ZrO2 modified electrode surface were clearly separated from each other when they co-existed in the physiological pH (pH 7.0) with a potential value of 140 mV (between AA and DA) and 330 mV (between AA and PA). It was, therefore, possible to simultaneously determine DA and PA in the samples at ERGO/ZrO2 nanocomposite modified GCE. Linear calibration curves were obtained for 9-237 μM of PA and DA. The ERGO/ZrO2 nanocomposite electrode has been satisfactorily used for the determination of DA and PA in the presence of AA at pharmaceutical formulations in human urine samples with a linear range of 3-174 μM. The proposed biosensor shows a wide linear range, low detection limit, good reproducibility and acceptable stability, providing a biocompatible platform for bio sensing and bio catalysis. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Development and in vivo evaluation of child-friendly lopinavir/ritonavir pediatric granules utilizing novel in situ self-assembly nanoparticles.

    Science.gov (United States)

    Pham, Kevin; Li, Diana; Guo, Shujie; Penzak, Scott; Dong, Xiaowei

    2016-03-28

    The aim of this study was to develop a nanotechnology to formulate a fixed-dose combination of poorly water-soluble drugs in a children-friendly, flexible solid dosage form. For diseases like HIV, pediatric patients are taking multiple drugs for effective treatments. Fixed-dose combinations could reduce pill burdens and costs as well as improving patient adherence. However, development of fixed-dose combinations of poorly water-soluble drugs for pediatric formulations is very challenging. We discovered a novel nanotechnology that produced in situ self-assembly nanoparticles (ISNPs) when the ISNP granules were introduced to water. In this study, antiretroviral drug granules, including lopinavir (LPV) ISNP granules and a fixed-dose combination of LPV/ritonavir (RTV) ISNP granules, were prepared using the ISNP nanotechnology, which spontaneously produced drug-loaded ISNPs in contact with water. Drug-loaded ISNPs had particle size less than 158nm with mono-dispersed distribution, over 95% entrapment efficiency for both LPV and RTV and stability over 8h in simulated physiological conditions. Drug-loaded ISNP granules with about 16% of LPV and 4% of RTV were palatable and stable at room temperature over 6months. Furthermore, LPV/RTV ISNP granules displayed a 2.56-fold increase in bioavailability and significantly increased LPV concentrations in tested tissues, especially in HIV sanctuary sites, as compared to the commercial LPV/RTV tablet (Kaletra®) in rats. Overall, the results demonstrated that the novel ISNP nanotechnology is a promising platform to manufacture palatable, "heat" stable, and flexible pediatric granules for fixed-dose combinations that can be used as sachets and sprinkles. To the best of our knowledge, this is the first report on this kind of novel nanotechnology for pediatric fixed-dose combinations of poorly water-soluble drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Synthesis of ZnO nanorods-Au nanoparticles hybrids via in-situ plasma sputtering-assisted method for simultaneous electrochemical sensing of ascorbic acid and uric acid

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Chao [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Liu, Hongying, E-mail: liuhongying@hdu.edu.cn [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Dan; Yang, Chi [Department of Pharmacy, Nantong University, Nantong 226001 (China); Zhang, Mingzhen [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China)

    2016-05-05

    In this study, ZnO nanorods-Au nanoparticles (ZnO NRs-Au NPs) hybrids were prepared using an in-situ plasma sputtering-assisted method without any template. Characterization results from scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy showed that Au NPs are highly dispersed and tightly anchored on the surface of ZnO NRs. The size and surface coverage of Au NPs were well controlled by plasma sputtering time. Moreover, the hybrids exhibited excellent electrocatalytic properties towards oxidation of ascorbic acid (AA) and uric acid (UA) due to large surface area of Au NPs and ZnO NRs, and thus can be used as electrochemical sensors. Differential pulse voltammetry results showed that AA and UA could be detected simultaneously by ZnO NRs-Au NPs hybrids modified glassy carbon electrode. The linear ranges for AA and UA are 0.1 to 4 mM and 0.01 to 0.4 mM, respectively. The results suggest promising future applications in clinical diagnosis. - Highlights: • ZnO nanorods-Au nanoparticles were synthesized by in-situ plasma sputtering method. • Influence of sputtering time on the formation of Au nanoparticles was studied. • It exhibited a strong electrocatalytic activity toward the oxidation of ascorbic acid and uric acid. • A portable and cheap approach for simultaneous detection of ascorbic acid and uric acid was developed.

  2. Synthesis of ZnO nanorods-Au nanoparticles hybrids via in-situ plasma sputtering-assisted method for simultaneous electrochemical sensing of ascorbic acid and uric acid

    International Nuclear Information System (INIS)

    Hou, Chao; Liu, Hongying; Zhang, Dan; Yang, Chi; Zhang, Mingzhen

    2016-01-01

    In this study, ZnO nanorods-Au nanoparticles (ZnO NRs-Au NPs) hybrids were prepared using an in-situ plasma sputtering-assisted method without any template. Characterization results from scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy showed that Au NPs are highly dispersed and tightly anchored on the surface of ZnO NRs. The size and surface coverage of Au NPs were well controlled by plasma sputtering time. Moreover, the hybrids exhibited excellent electrocatalytic properties towards oxidation of ascorbic acid (AA) and uric acid (UA) due to large surface area of Au NPs and ZnO NRs, and thus can be used as electrochemical sensors. Differential pulse voltammetry results showed that AA and UA could be detected simultaneously by ZnO NRs-Au NPs hybrids modified glassy carbon electrode. The linear ranges for AA and UA are 0.1 to 4 mM and 0.01 to 0.4 mM, respectively. The results suggest promising future applications in clinical diagnosis. - Highlights: • ZnO nanorods-Au nanoparticles were synthesized by in-situ plasma sputtering method. • Influence of sputtering time on the formation of Au nanoparticles was studied. • It exhibited a strong electrocatalytic activity toward the oxidation of ascorbic acid and uric acid. • A portable and cheap approach for simultaneous detection of ascorbic acid and uric acid was developed.

  3. Development of an in-situ diagnostic for the measurement of the hydrogen content of amorphous hydrocarbon layers in fusion devices

    International Nuclear Information System (INIS)

    Irrek, F.

    2008-07-01

    a diagnostic method, the laser-induced thermal desorption spectroscopy (LDS), is developed to measure in situ the hydrogen inventory in the surface of plasma-facing components in fusion experiments. Its capabilities will be demonstrated in TEXTOR. In LDS, during the plasma discharge a laser beam is used to heat a spot on a surface close to the plasma to a temperature of 1400 to 2100 K to a depth of 100 μm. Trapped hydrogen will be released into the plasma where it emits line radiation. The emitted H a -light is quantitatively measured. The amount of released hydrogen is calculated from the intensity of this emission using conversion factors (S/XB) eff . The laser light (Nd:YAG, 1064 nm) is conducted via light fibres. At TEXTOR, a 5 mm 2 sized homogeneous laser spot is created with a pulse duration of 1.5 ms, and an Energy of 5 J, typically. Below the laser spot a volume of at most 1 mm 3 is desorbed. The generated temperature is calculated numerically and indirectly deduced from surface changings. Depending on the conditions during the layer formation the hydrogen content of the hydrocarbon layer will vary and different fractions of the released molecules (H 2 , CH 4 , C 2 H 4 ) are created during the laser heating. The release of atomic hydrogen by laser desorption was not found. The emitted light is measured by means of narrow-band interference filters and a CCD-camera. The fraction of the light emission which lies outside the observation volume is estimated using simulations of the emission by the neutral gas transport Monte Carlo code EIRENE for each molecular fraction. Conversion factors (S/XB) eff were measured in various reference plasmas (T e =22-30 eV, n e =1-11 x 10 18 m -3 and T e =50-74 eV, n e =1-5 x 10 18 m -3 ) by desorbing prepared graphite samples which release a known amount of hydrogen with a known molecular distribution. LDS measurements were carried out in TEXTOR at hydrocarbon layers deposited on a graphite test limiter. The desorbed layers

  4. Study of water adsorption and capillary bridge formation for SiO(2) nanoparticle layers by means of a combined in situ FT-IR reflection spectroscopy and QCM-D set-up.

    Science.gov (United States)

    Torun, B; Kunze, C; Zhang, C; Kühne, T D; Grundmeier, G

    2014-04-28

    Water adsorption and capillary bridge formation within a layer of SiO2-nanoparticles were studied in situ by means of a combination of quartz crystal microbalance (QCM-D) with dissipation analysis and Fourier transformation infrared reflection absorption spectroscopy (FT-IRRAS). FT-IR data were employed to distinguish the "ice-like" and "liquid-like" contributions and to support the analysis of the QCM-D data concerning mass change and dissipation. Combined measurements show that for SiO2-nanoparticles with a diameter of about 250 nm, the formation of two adsorbed monolayers of water as well as bulk water leads to a rather linear increase in the dissipation for relative humidity values of up to 60% which is followed by a strong increase in dissipation during the actual liquid bridge formation. Subsequently, the dissipation drops again when the relative humidity is further increased to values >90%.

  5. In situ generation of silver nanoparticles in poly(vinyl alcohol)/poly(acrylic acid) polymer membranes in the absence of reducing agent and their effect on pervaporation of a water/acetic acid mixture

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhard, Shvshankar; Kwon, Yong Sung; Moon, MyungJun; Shon, Min Young [Dept. of Industrial Chemistry, Pukyong National University, Busan (Korea, Republic of); Park, You In; Nam, Seung Eun [Center for membranes, Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of)

    2016-12-15

    The in situ generation of silver nanoparticles in a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) polymer matrix in the absence of any additional reducing agent is reported and tends to the membrane fabrication using solution-casting. Its effect on the separation of a water/acetic acid mixture by pervaporation is described. The results of UV spectroscopy, scanning electron microscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses showed that the silver nanoparticles were successfully prepared and well dispersed in the polymer matrix. The increased hydrophilicity of the PVA/PAA membrane due to the presence of silver nanoparticles was confirmed by Fourier transform infrared spectroscopy, contact angle measurements, and membrane absorption studies. Pervaporation data for composite membranes showed a three-fold increase in the flux value, while the initially decreased separation factor subsequently showed a constant value. Overall, the pervaporation data suggested that the presence of silver nanoparticles benefited the dehydration process.

  6. In situ generation of silver nanoparticles in poly(vinyl alcohol)/poly(acrylic acid) polymer membranes in the absence of reducing agent and their effect on pervaporation of a water/acetic acid mixture

    International Nuclear Information System (INIS)

    Chaudhard, Shvshankar; Kwon, Yong Sung; Moon, MyungJun; Shon, Min Young; Park, You In; Nam, Seung Eun

    2016-01-01

    The in situ generation of silver nanoparticles in a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) polymer matrix in the absence of any additional reducing agent is reported and tends to the membrane fabrication using solution-casting. Its effect on the separation of a water/acetic acid mixture by pervaporation is described. The results of UV spectroscopy, scanning electron microscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses showed that the silver nanoparticles were successfully prepared and well dispersed in the polymer matrix. The increased hydrophilicity of the PVA/PAA membrane due to the presence of silver nanoparticles was confirmed by Fourier transform infrared spectroscopy, contact angle measurements, and membrane absorption studies. Pervaporation data for composite membranes showed a three-fold increase in the flux value, while the initially decreased separation factor subsequently showed a constant value. Overall, the pervaporation data suggested that the presence of silver nanoparticles benefited the dehydration process

  7. A novel flexible clinical multiphoton tomograph for early melanoma detection, skin analysis, testing of anti-age products, and in situ nanoparticle tracking

    Science.gov (United States)

    Weinigel, Martin; Breunig, Hans Georg; Gregory, Axel; Fischer, Peter; Kellner-Höfer, Marcel; Bückle, Rainer; König, Karsten

    2010-02-01

    High-resolution 3D microscopy based on multiphoton induced autofluorescence and second harmonic generation have been introduced in 1990. 13 years later, CE-marked clinical multiphoton systems for 3D imaging of human skin with subcellular resolution have first been launched by JenLab company with the tomography DermaInspect®. This year, the second generation of clinical multiphoton tomographs was introduced. The novel multiphoton tomograph MPTflex, equipped with a flexible articulated optical arm, provides an increased flexibility and accessibility especially for clinical and cosmetical examinations. Improved image quality and signal to noise ratio (SNR) are achieved by a very short source-drain spacing, by larger active areas of the detectors and by single photon counting (SPC) technology. Shorter image acquisition time due to improved image quality reduces artifacts and simplifies the operation of the system. The compact folded optical design and the light-weight structure of the optical head eases the handling. Dual channel detectors enable to distinguish between intratissue elastic fibers and collagenous structures simultaneously. Through the use of piezo-driven optics a stack of optical cross-sections (optical sectioning) can be acquired and 3D imaging can be performed. The multiphoton excitation of biomolecules like NAD(P)H, flavins, porphyrins, elastin, and melanin is done by picojoule femtosecond laser pulses from an tunable turn-key femtosescond near infrared laser system. The ability for rapid high-quality image acquisition, the user-friendly operation of the system and the compact and flexible design qualifies this system to be used for melanoma detection, diagnostics of dermatological disorders, cosmetic research and skin aging measurements as well as in situ drug monitoring and animal research.

  8. Progress in Development of C60 Nanoparticle Plasma Jet for Diagnostic of Runaway Electron Beam-Plasma Interaction and Disruption Mitigation Study for ITER

    Science.gov (United States)

    Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.

    2013-10-01

    We produced a C60 nanoparticle plasma jet (NPPJ) with uniquely fast response-to-delivery time (~ 1 - 2 ms) and unprecedentedly high momentum (~ 0 . 6 g .km/s). The C60 NPPJ was obtained by using a solid state TiH2/C60 pulsed power cartridge producing ~180 mg of C60 molecular gas by sublimation and by electromagnetic acceleration of the C60 plasma in a coaxial gun (~35 cm length, 96 kJ energy) with the output of a high-density (>1023 m-3) hyper-velocity (>4 km/s) plasma jet. The ~ 75 mg C60/C plasma jet has the potential to rapidly and deeply deliver enough mass to significantly increase electron density (to ne ~ 2 . 4 ×1021 m-3, i.e. ~ 60 times larger than typical DIII-D pre-disruption value, ne 0 ~ 4 ×1019 m-3), and to modify the 'critical electric field' and the runaway electrons (REs) collisional drag during different phases of REs dynamics. The C60 NPPJ, as a novel injection technique, allows RE beam-plasma interaction diagnostic by quantitative spectroscopy of C ions visible/UV line intensity. The system is scalable to ~ 1 - 2 g C60/C plasma jet output and technology is adaptable to ITER acceptable materials (BN and Be) for disruption mitigation. Work supported by US DOE DE-FG02-08ER85196 grant.

  9. Diagnostic Criteria in Intraepithelial Pagetoid Neoplasms: A Histopathologic Study and Evaluation of Select Features in Paget Disease, Bowen Disease, and Melanoma In Situ.

    Science.gov (United States)

    Elbendary, Amira; Xue, Ruzeng; Valdebran, Manuel; Torres, Kara Melissa T; Parikh, Kruti; Elattar, Inas; Kwon, Eun Ji; Elston, Dirk M

    2017-06-01

    Paget disease, Bowen disease, and malignant melanoma in situ are intraepidermal neoplasms, characterized by the presence of pagetoid scatter of atypical cells in the epidermis. This study reviewed the frequency of select histologic criteria to validate their usefulness in the histologic distinction between these entities. One hundred forty-four specimens with the diagnosis of Bowen disease, 144 specimens with Paget disease (mammary and extramammary), and 144 specimens with malignant melanoma in situ were examined microscopically to define frequencies of select histologic criteria present in each disease. Comparison between mammary Paget and extramammary Paget disease showed no significant differences in the features studied. Crushing of basal keratinocytes, presence of atypical cells in the corneum, and presence of large cells with amphophilic cytoplasm were significantly noted in Paget disease. Transition between the atypical clear cells and surrounding keratinocytes was absent in all cases of melanoma in situ and in 87 (60.4%) cases of Paget disease, but it was significantly associated with Bowen disease (98.6%). Dyskeratotic cells were significantly associated with Bowen disease cases. Our study demonstrated a practical histologic approach to differentiate between intraepidermal pagetoid neoplasms. Careful histologic study of the proposed criteria may reduce reliance on immunohistochemical stains.

  10. In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

    Science.gov (United States)

    Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

    2017-07-04

    In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. In situ

    Science.gov (United States)

    Tremsin, Anton S; Makowska, Małgorzata G; Perrodin, Didier; Shalapska, Tetiana; Khodyuk, Ivan V; Trtik, Pavel; Boillat, Pierre; Vogel, Sven C; Losko, Adrian S; Strobl, Markus; Kuhn, L Theil; Bizarri, Gregory A; Bourret-Courchesne, Edith D

    2016-06-01

    Neutrons are known to be unique probes in situations where other types of radiation fail to penetrate samples and their surrounding structures. In this paper it is demonstrated how thermal and cold neutron radiography can provide time-resolved imaging of materials while they are being processed ( e.g. while growing single crystals). The processing equipment, in this case furnaces, and the scintillator materials are opaque to conventional X-ray interrogation techniques. The distribution of the europium activator within a BaBrCl:Eu scintillator (0.1 and 0.5% nominal doping concentrations per mole) is studied in situ during the melting and solidification processes with a temporal resolution of 5-7 s. The strong tendency of the Eu dopant to segregate during the solidification process is observed in repeated cycles, with Eu forming clusters on multiple length scales (only for clusters larger than ∼50 µm, as limited by the resolution of the present experiments). It is also demonstrated that the dopant concentration can be quantified even for very low concentration levels (∼0.1%) in 10 mm thick samples. The interface between the solid and liquid phases can also be imaged, provided there is a sufficient change in concentration of one of the elements with a sufficient neutron attenuation cross section. Tomographic imaging of the BaBrCl:0.1%Eu sample reveals a strong correlation between crystal fractures and Eu-deficient clusters. The results of these experiments demonstrate the unique capabilities of neutron imaging for in situ diagnostics and the optimization of crystal-growth procedures.

  12. In-situ fluorimetry: A powerful non-invasive diagnostic technique for natural dyes used in artefacts. Part II. Identification of orcein and indigo in Renaissance tapestries

    Science.gov (United States)

    Clementi, C.; Miliani, C.; Romani, A.; Santamaria, U.; Morresi, F.; Mlynarska, K.; Favaro, G.

    2009-01-01

    In this paper, three Renaissance tapestries depicting scenes painted by Raffaello Sanzio, conserved at the Vatican Museum, were investigated using in-situ UV-Visible fluorimetric measurements. The results show that this technique is suitable for the detection of natural organic colorants used for dyeing the threads woven in these tapestries. The emission signals detected on red-purple colours were assigned to the colorant orcein and those on different nuances of blue and green colours to indigo by comparison with data from reference laboratory samples. The assignments were supported by chromatographic experiments carried out on threads taken from the back side of the tapestry in the same points analysed by spectrofluorimentry.

  13. The three-dimensional positioning system at the VINETA.II experiment—a multipurpose tool for in situ plasma diagnostics

    Science.gov (United States)

    Shesterikov, I.; Milojevic, D.; von Stechow, A.; Rahbarnia, K.; Grulke, O.; Klinger, T.

    2017-08-01

    The manipulator systems installed at the VINETA.II magnetic reconnection experiment are essential elements for experimental investigation of local plasma parameters. A novel three-dimensional (3D) probe manipulator has been designed, implemented and successfully operated at VINETA.II. This work presents its design and performance for three-dimensional measurements of VINETA.II plasmas. Its design consists of three vertically stacked independent and mutually perpendicular linear motion stages which allow flexible positioning of diagnostic tools such as electrical and magnetic probes or optical diagnostics within the vacuum vessel. Its design features include a wide spatial coverage, sub-millimeter positioning accuracy and the capability to operate in a harsh environment under the influence of microwaves, radio-frequency waves and direct contact with plasma. Manipulator performance is assessed by measuring a volumetric distribution of plasma parameters by a B-dot probe. A typical discharge of the magnetic reconnection setup in VINETA.II with a pulse time of τ=600 μs is chosen for this purpose. The azimuthal magnetic field distribution measured with the 3D manipulator agrees favorably with measurements obtained by the two-dimensional (2D) manipulator, used at VINETA.II as a standard reference diagnostic tool, thereby demonstrating its reliability and performance. A programmable stepper motor controller (TMCM-1110) that is operated remotely by a PC drives all possible features of the manipulator system.

  14. Investigations on in situ diagnostics by an infrared camera to distinguish between the plasma facing tiles with carbonaceous surface layer and defect in the underneath junction

    International Nuclear Information System (INIS)

    Cai, Laizhong; Gauthier, Eric; Corre, Yann; Liu, Jian

    2013-01-01

    Both a deposition surface layer and a delamination underneath junction existing on plasma facing components (PFCs) can result in abnormal high surface temperature under normal heating conditions. The tile with delamination has to be replaced to prevent from a critical failure (complete delamination) during plasma operation while the carbon deposit can be removed without any repairing. Therefore, distinguishing in situ deposited tiles and junction defect tiles is crucial to avoid the critical failure without unwanted shutdown. In this paper, the thermal behaviors of junction defect tiles and carbon deposit tiles are simulated numerically. A modified time constant method is then introduced to analyze the thermal behaviors of deposited tiles and junction defect tiles. The feasibility of discrimination by analyzing the thermal behaviors of tiles is discussed and the requirements of this method for discrimination are described. Finally, the time resolution requirement of IR cameras to do the discrimination is mentioned

  15. An In-situ materials analysis particle probe (MAPP) diagnostic to study particle density control and hydrogenic fuel retention in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Allain, Jean-Paul [Purdue Univ., West Lafayette, IN (United States)

    2014-09-05

    A new materials analysis particle probe (MAPP) was designed, constructed and tested to develop understanding of particle control and hydrogenic fuel retention in lithium-based plasma-facing surfaces in NSTX. The novel feature of MAPP is an in-situ tool to probe the divertor NSTX floor during LLD and lithium-coating shots with subsequent transport to a post-exposure in-vacuo surface analysis chamber to measure D retention. In addition, the implications of a lithiated graphite-dominated plasma-surface environment in NSTX on LLD performance, operation and ultimately hydrogenic pumping and particle control capability are investigated in this proposal. MAPP will be an invaluable tool for erosion/redeposition simulation code validation.

  16. In-situ formation of silver nanoparticles on poly (lactic acid) film by γ-radiation induced grafting of N-vinyl pyrrolidone

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingxia; Chen, Hao; Chen, Zhuping; Chen, Yuheng; Guo, Dan; Ni, Maojun; Liu, Siyang; Peng, Chaorong, E-mail: pengchaorong_siae@163.com

    2016-06-01

    A fast, easy and novel method for preparing biodegradable polymer films with silver nanoparticles was investigated to endow the material with excellent biocompatibility and antibacterial property. Silver nanoparticles (Ag NPs) were immobilized on the surface of polylactic acid (PLA) film by gamma radiation induced grafting of N-vinyl pyrrolidone (NVP). In this method, poly (N-vinyl pyrrolidone) (PVP) was produced and grafted onto the surface of PLA film by gamma radiation polymerization of NVP. PVP acted as both a bridge to connect the Ag NPs with the PLA film, and a stabilizer to protect the Ag NPs from agglomeration. The effect of various reaction parameters, including NVP/Ag mole ratio and radiation dose, on the fabrication of PLA-g-NVP/Ag film was demonstrated. Moreover, the interaction between PVP and Ag NPs was studied by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, that revealed the Ag NPs coordinated through the oxygen atom on the carbonyl group of PVP at 15 kGy radiation dose, but through the nitrogen atom and the oxygen atom of the amide group of PVP at 1 kGy dose. - Highlights: • PLA-graft-NVP/Ag film was produced by a simple one-step method. • Ag nanoparticles were immobilized on PLA film by gamma radiation grafting technology. • PVP acted as a bridge to connect Ag nanoparticles and PLA film. • Different content and size of Ag NPs can be reached by varying radiation dose.

  17. Melanoma-Targeted Chemo thermo therapy and In Situ Peptide Immunotherapy through HSP Production by Using Melanogenesis Substrate, NPrCAP, and Magnetite Nanoparticles

    International Nuclear Information System (INIS)

    Jimbow, K.; Osai, Y. I.; Jimbow, K.; Kamiya, T.; Yamashita, T.; Yoneta, A.; Ito, S.; Wakamatsu, K.; Tamura, Y.; Ito, A.; Honda, H.; Murase, K.; Nohara, S.; Nakayama, E.; Hasegawa, T.; Yamamoto, I.; Kobayashi, T.

    2013-01-01

    Exploitation of biological properties unique to cancer cells may provide a novel approach to overcome difficult challenges to the treatment of advanced melanoma. In order to develop melanoma-targeted chemo thermo immuno therapy, a melanogenesis substrate, N-propionyl-4-S-cysteaminylphenol (NPrCAP), sulfur-amine analogue of tyrosine, was conjugated with magnetite nanoparticles. NPrCAP was exploited from melanogenesis substrates, which are expected to be selectively incorporated into melanoma cells and produce highly reactive free radicals through reacting with tyrosinase, resulting in chemotherapeutic and immunotherapeutic effects by oxidative stress and apoptotic cell death. Magnetite nanoparticles were conjugated with NPrCAP to introduce thermo therapeutic and immunotherapeutic effects through non apoptotic cell death and generation of heat shock protein (HSP) upon exposure to alternating magnetic field (AMF). During these therapeutic processes, NPrCAP was also expected to provide melanoma-targeted drug delivery system.

  18. Protein-directed in situ synthesis of platinum nanoparticles with superior peroxidase-like activity, and their use for photometric determination of hydrogen peroxide

    International Nuclear Information System (INIS)

    Chen, Lijian; Wang, Nan; Wang, Xindong; Ai, Shiyun

    2013-01-01

    Platinum nanoparticles (Pt-NPs) with sizes in the range from 10 to 30 nm were synthesized using protein-directed one-pot reduction. The model globular protein bovine serum albumin (BSA) was exploited as the template, and the resulting BSA/Pt-NPs were studied by transmission electron microscopy, energy dispersive X-ray spectroscopy, and resonance Rayleigh scattering spectroscopy. The modified nanoparticles display a peroxidase-like activity that was exploited in a rapid method for the colorimetric determination of hydrogen peroxide which can be detected in the 50 μM to 3 mM concentration range. The limit of detection is 7.9 μM, and the lowest concentration that can be visually detected is 200 μM. (author)

  19. Melanoma-Targeted Chemothermotherapy and In Situ Peptide Immunotherapy through HSP Production by Using Melanogenesis Substrate, NPrCAP, and Magnetite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Kowichi Jimbow

    2013-01-01

    Full Text Available Exploitation of biological properties unique to cancer cells may provide a novel approach to overcome difficult challenges to the treatment of advanced melanoma. In order to develop melanoma-targeted chemothermoimmunotherapy, a melanogenesis substrate, N-propionyl-4-S-cysteaminylphenol (NPrCAP, sulfur-amine analogue of tyrosine, was conjugated with magnetite nanoparticles. NPrCAP was exploited from melanogenesis substrates, which are expected to be selectively incorporated into melanoma cells and produce highly reactive free radicals through reacting with tyrosinase, resulting in chemotherapeutic and immunotherapeutic effects by oxidative stress and apoptotic cell death. Magnetite nanoparticles were conjugated with NPrCAP to introduce thermotherapeutic and immunotherapeutic effects through nonapoptotic cell death and generation of heat shock protein (HSP upon exposure to alternating magnetic field (AMF. During these therapeutic processes, NPrCAP was also expected to provide melanoma-targeted drug delivery system.

  20. On-chip bioorthogonal chemistry enables immobilization of in situ modified nanoparticles and small molecules for label-free monitoring of protein binding and reaction kinetics.

    Science.gov (United States)

    Tassa, C; Liong, M; Hilderbrand, S; Sandler, J E; Reiner, T; Keliher, E J; Weissleder, R; Shaw, S Y

    2012-09-07

    Efficient methods to immobilize small molecules under continuous-flow microfluidic conditions would greatly improve label-free molecular interaction studies using biosensor technology. At present, small-molecule immobilization chemistries require special conditions and in many cases must be performed outside the detector and microfluidic system where real-time monitoring is not possible. Here, we have developed and optimized a method for on-chip bioorthogonal chemistry that enables rapid, reversible immobilization of small molecules with control over orientation and immobilization density, and apply this technique to surface plasmon resonance (SPR) studies. Immobilized small molecules reverse the orientation of canonical SPR interaction studies, and also enable a variety of new SPR applications including on-chip assembly and interaction studies of multicomponent structures, such as functionalized nanoparticles, and measurement of bioorthogonal reaction rates. We use this approach to demonstrate that on-chip assembled functionalized nanoparticles show a preserved ability to interact with their target protein, and to measure rapid bioorthogonal reaction rates with k(2) > 10(3) M(-1) s(-1). This method offers multiple benefits for microfluidic biological applications, including rapid screening of targeted nanoparticles with vastly decreased nanoparticle synthetic requirements, robust immobilization chemistry in the presence of serum, and a continuous flow technique that mimics biologic contexts better than current methods used to measure bioorthogonal reaction kinetics such as NMR or UV-vis spectroscopy (e.g., stopped flow kinetics). Taken together, this approach constitutes a flexible and powerful technique for evaluating a wide variety of reactions and intermolecular interactions for in vitro or in vivo applications.

  1. In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kliewer, Christopher J. [Univ. of California, Berkeley, CA (United States)

    2009-06-30

    Sum frequency generation surface vibrational spectroscopy (SFG-VS) in combination with gas chromatography (GC) was used in-situ to monitor surface bound reaction intermediates and reaction selectivities for the hydrogenation reactions of pyrrole, furan, pyridine, acrolein, crotonaldehyde, and prenal over Pt(111), Pt(100), Rh(111), and platinum nanoparticles under Torr reactant pressures and temperatures of 300K to 450K. The focus of this work is the correlation between the SFG-VS observed surface bound reaction intermediates and adsorption modes with the reaction selectivity, and how this is affected by catalyst structure and temperature. Pyrrole hydrogenation was investigated over Pt(111) and Rh(111) single crystals at Torr pressures. It was found that pyrrole adsorbs to Pt(111) perpendicularly by cleaving the N-H bond and binding through the nitrogen. However, over Rh(111) pyrrole adsorbs in a tilted geometry binding through the {pi}-aromatic orbitals. A surface-bound pyrroline reaction intermediate was detected over both surfaces with SFG-VS. It was found that the ring-cracking product butylamine is a reaction poison over both surfaces studied. Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity. Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran. Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The α-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt(100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation. The hydrogenation of the

  2. In-situ PXRD studies of ZnO nanoparticle growth: How do various salts influence the hydrothermal growth of ZnO?

    DEFF Research Database (Denmark)

    Bøjesen, Espen Drath

    the broadest range of nanostructures. Previously many different in-situ characterization methods have been used to investigate the ZnO formation under various synthesis conditions; these include UV-VIS and SAXS. These methods were primarily used to give information on particle size of ZnO formed using soft...... chemical methods and non-aqueous solvents. In our work we have studied the formation of ZnO during hydrothermal syntheses using in-situ powder X-ray diffraction, thus enabling us to extract crystallographic as well as microstructural information. The data was analyzed using Rietveld refinement and whole...... powder pattern modeling. Among the parameters studied were the influence of temperature, type of base used and how different ionic salts influence the growth. Results include findings that suggest that sodium nitrate influences the aspect ratio of synthesized particles and that lithium nitrate generally...

  3. APPLICATION OF LASERS AND LASER-OPTICAL METHODS IN LIFE SCIENCES Spectroscopy of nanoparticles based on Gd14B6Ge2O34 polycrystals and La2O3 — B2O3 glasses, activated by Nd3+ ions, for cancer diagnostics

    Science.gov (United States)

    Popov, A. V.; Ryabova, A. V.; Komova, M. G.; Krut'ko, V. A.; Petrova, O. B.; Loshchenov, V. B.; Voronko, Yu K.

    2011-01-01

    Nanoparticles of gadolinium borate polycrystals and borate glasses, activated by Nd3+ ions, are obtained from macroscopic samples of the corresponding compositions by mechanical grinding and ultrasonic dispersion in water. A spectroscopic study of these nanoparticles in the near-IR region is performed to determine their potential as luminescence biosensors and radiopharmaceutical preparations for cancer diagnostics by radiosensitive methods. A twofold increase in the lifetime of the metastable 4F3/2 state of Nd3+ ions at the transition from submicron polycrystalline particles to nanoparticles is experimentally found. A study of the nanoparticle distribution over organs and tissues of laboratory animals, performed with a 810-nm laser for exciting luminescence and a multichannel fibre spectrometer for measuring fluorescence in the range of 0.8 — 1.2 mm, showed this technique to be sufficiently sensitive to reliably determine the nanoparticle concentration in biological tissues and the dynamics of its change.

  4. Development of a facile and effective electrochemical strategy for preparation of iron oxides (Fe{sub 3}O{sub 4} and γ-Fe{sub 2}O{sub 3}) nanoparticles from aqueous and ethanol mediums and in situ PVC coating of Fe{sub 3}O{sub 4} superparamagnetic nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Karimzadeh, Isa [Faculty of Physics, Semnan University, Semnan (Iran, Islamic Republic of); Dizaji, Hamid Rezagholipour, E-mail: hrgholipour@semnan.ac.ir [Faculty of Physics, Semnan University, Semnan (Iran, Islamic Republic of); Aghazadeh, Mustafa [NFCRS, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2016-10-15

    To attain reliable and high performance in biomedical applications, magnetic particles with regular spherical shape, narrow size distributions, high-saturation magnetization, and good dispersion in liquid media is very important. Therefore, the synthesis of monodispersed, water-dispersible, and regular spherical superparamagnetic iron oxides nanoparticles (SPIONs) with high saturation magnetization will be of great importance. Here we report a facile, fact and simple electrochemical tactic for preparation of SPIONs and their one step in situ surface engineering in both aqueous and ethanol mediums. In this platform, optimum and simple electrochemical conditions were first constructed for preparation of Fe{sub 3}O{sub 4} and γ-Fe{sub 2}O{sub 3} nanoparticles in both ethanol and aqueous mediums, and monodispersed nanoparticles with superparamagnetic properties were prepared. The field emission scanning and transmission electron microscopy (FE-SEM and TEM) observations revealed that the electrodeposited nanoparticles have roughly spherical and homogeneous shape with narrow size distribution. Then, Fe{sub 3}O{sub 4} nanoparticles were coated by polyvinyl chloride (PVC) during deposition process. The PVC coating on SPIONs surface was confirmed by Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), differential scanning calorimetry (DSC), and thermogravimetric (TG) analyses. Results of vibrating sample magnetometer (VSM) indicated that the prepared SPIONs exhibit superparamagnetic behavior including negligible remnant magnetization and negligible coercivity, and high saturation magnetization at room temperature. PVC coated SPIONs exhibited saturation magnetization value of 43.72 emu/g, and negligible remnant magnetization and coercivity (Mr~0.15 emu/g and Ce~0.5 Oe, respectively). Based on the obtained results, it was concluded this electrochemical strategy can be introduced as a novel and clean platform for preparation of variety polymer and

  5. Effect of silver nanoparticle on the properties of poly (methyl ...

    Indian Academy of Sciences (India)

    silver nanoparticles (PMMA/AgNPs) nanocomposite networks prepared via in situ photoiniferter-mediated photopolymerization (in situ PMP) using tetraethylthiuram disulphide (TED) as photoiniferter and 2,2-dimethoxy-2-phenylacetophenone ...

  6. Nanoparticle formation and thin film deposition in aniline containing plasmas

    Science.gov (United States)

    Pattyn, Cedric; Dias, Ana; Hussain, Shahzad; Strunskus, Thomas; Stefanovic, Ilija; Boulmer-Leborgne, Chantal; Lecas, Thomas; Kovacevic, Eva; Berndt, Johannes

    2016-09-01

    This contribution deals with plasma based polymerization processes in mixtures of argon and aniline. The investigations are performed in a capacitively coupled RF discharge (in pulsed and continuous mode) and concern both the observed formation of nanoparticles in the plasma volume and the deposition of films. The latter process was used for the deposition of ultra-thin layers on different kind of nanocarbon materials (nanotubes and free standing graphene). The analysis of the plasma and the plasma chemistry (by means of mass spectroscopy and in-situ FTIR spectroscopy) is accompanied by several ex-situ diagnostics of the obtained materials which include NEXAFS and XPS measurements as well as Raman spectroscopy and electron microscopy. The decisive point of the investigations concern the preservation of the original monomer structure during the plasma polymerization processes and the stability of the thin films on the different substrates.

  7. Cadmium oxide nanoparticles grown in situ on reduced graphene oxide for enhanced photocatalytic degradation of methylene blue dye under ultraviolet irradiation.

    Science.gov (United States)

    Kumar, Sumeet; Ojha, Animesh K; Walkenfort, Bernd

    2016-06-01

    Cadmium oxide (CdO) nanoparticles (NPs), reduced graphene oxide (rGO) and rGO-CdO nanocomposites have been synthesized using one step hydrothermal method. The structural and optical properties of CdO NPs, rGO, and rGO-CdO nanocomposites were investigated by X-ray diffraction (XRD), energy dispersive X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), Raman spectroscopy (RS), ultraviolet-visible spectroscopy (UV-Vis.) and photoluminescence (PL) spectroscopy techniques. The rGO has a sharp 2D peak compared to GO. The sharp nature of 2D band may be due to the larger contribution from single layer sheet. The photocatalytic activity of the synthesized samples has been investigated under UV irradiation. The results of photocatalytic measurements revealed that ~80% of MB dye is degraded by adding the rGO-CdO nanocomposites as photocatalysts into the dye solution. The decrease in the intensity of emission peaks indicates that the photogenerated charge carriers have been transferred from CdO NPs to rGO sheets, which causes to increase the density of O2(-) and OH radicals in the dye solution. The CdO nanoparticles gown on the rGO sheets showed enhanced ferromagnetism (FM) at room temperature, which may be attributed to the short range magnetic interaction of magnetic moments of CdO NPs and spin units present on the rGO sheets. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Biosynthesis of silver nanoparticles using Stevia extracts

    International Nuclear Information System (INIS)

    Laguta, I.V.; Fesenko, T.V.; Stavinskaya, O.N.; Shpak, L.M.; Dzyuba, O.I.

    2015-01-01

    Silver nanoparticles are synthesized using Stevia rebaudiana extracts. It is shown that the rate of nanoparticles formation is affected by plant cultivation conditions. It is found that, in the presence of the extract from callus, the formation of nanoparticles occurs faster than in the presence of extracts from plants grown under conditions of ex situ and in vitro. The synthesized silver nanoparticles were studied by UV and IR spectroscopies

  9. Combined in situ small and wide angle X-ray scattering studies of TiO2 nano-particle annealing to 1023 K

    DEFF Research Database (Denmark)

    Kehres, Jan; Andreasen, Jens Wenzel; Krebs, Frederik C

    2010-01-01

    Combined in situ small- and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a recently developed laboratory setup to investigate the dynamical properties of dry oleic acid-capped titanium dioxide nanorods during annealing in an inert gas stream in a temperature interval of 298......-1023 K. Aggregates formed by the titanium dioxide particles exhibit a continuous growth as a function of temperature. The particle size determined with SAXS and the crystallite size refined from WAXS show a correlated growth at temperatures above 673 K, where the decomposition of the surfactant...... microscopy studies of the sample. Transmission electron microscopy shows a transformation from a rod to a spherical particle shape; the WAXS data indicate that the shape change occurs in a temperature interval of 773-923 K. The highly crystalline titanium dioxide particles remain in the metastable anatase...

  10. In-situ construction of Au nanoparticles confined in double-shelled TiO2/mSiO2 hollow architecture for excellent catalytic activity and enhanced thermal stability

    Science.gov (United States)

    Fang, Jiasheng; Zhang, Yiwei; Zhou, Yuming; Zhang, Chao; Zhao, Shuo; Zhang, Hongxing; Sheng, Xiaoli

    2017-01-01

    A facile strategy has been developed for the synthesis of H-TS-Au microspheres (MCs) with double-shelled hollow architecture and sub-5 nm Au nanoparticles (Au NPs). The synthetic procedure involves the successive sol-gel template-assisted method for the preparation of uniform hierarchical hollow-in-hollow H-TS MCs with TiO2/mSiO2 as yolks/shells, and the unique deposition-precipitation method mediated with Au(en)2Cl3 precursors for the in-situ construction of extremely stable Au NPs under a low-temperature hydrogen reduction. The synthesized H-TS-Au MCs were characterized by TEM, SEM, FTIR, XRD, BET and UV-vis absorption spectra. Catalytic activity of H-TS-Au was evaluated using the reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) by NaBH4. Results established that H-TS-Au MCs possessed a large-size double-shelled architecture with high structural integrity and robustness,which can effectively confine numerous tiny Au NPs and restrict them from sintering aggregation even up to further calcination at 800 °C. Owing to the advantageous structural configuration and the synergistic effect of TiO2/mSiO2 double shells, the H-TS-Au MCs were demonstrated to exhibit a remarkable catalytic activity and stability, and preserve the intact morphology after 6 repeating reduction of 4-NP.

  11. Modification of PLGA nanoparticles for improved properties as a 99mTc-labeled agent in sentinel lymph node detection.

    Science.gov (United States)

    Subramanian, Suresh; Pandey, Usha; Gugulothu, Dalapathi; Patravale, Vandana; Samuel, Grace

    2013-10-01

    We have earlier reported on the possible application of poly [lactide (co-glycolide)] (PLGA) nanoparticles of suitable size to serve as a (99m)Tc-labeled diagnostic tracer in sentinel lymph node detection (SLND). Additional efforts have now been made to improve both the radiolabeling yield and the biological efficacy by modifying the PLGA particles. Two approaches were taken, one based on in situ loading of mebrofenin inside PLGA nanoparticles and the second one based on functionalization of existing terminal carboxylic acid groups on the nanoparticle surface with p-aminobenzyl diethylenetriamine pentaacetic acid (p-NH2-Bz-DTPA) for enhanced availability of functional groups suitable for (99m)Tc complexation. The modified PLGA derivatives were purified and characterized. Radiolabeling of the modified PLGA nanoparticles was carried out with (99m)Tc using stannous chloride as the reducing agent. Mebrofenin encapsulated PLGA nanoparticles (mebrofenin-PLGA) did not show any significant improvement in the radiolabeling yield in comparison to the earlier reported "plain" PLGA nanoparticles, probably due to inaccessibility of the mebrofenin moiety to (99m)Tc upon encapsulation. DTPA-conjugated PLGA nanoparticles (DTPA-PLGA) showed appreciable improvement in radiolabeling yield under more moderate reaction conditions and better stability. In the biological evaluation performed in Wistar rat model, (99m)Tc-DTPA-PLGA nanoparticles showed a considerable increase in uptake in the sentinel node and the percentage popliteal extraction of the preparation was also higher. (99m)Tc-mebrofenin-PLGA did not show any improvement in SLN uptake over plain PLGA nanoparticles. The above results suggest that surface modification of PLGA by covalently coupling DTPA to PLGA nanoparticles prior to (99m)Tc labeling appears to be a superior approach to achieve a suitable (99m)Tc-labeled PLGA nanoparticle preparation for SLND.

  12. In situ decoration of plasmonic Au nanoparticles on graphene quantum dots-graphitic carbon nitride hybrid and evaluation of its visible light photocatalytic performance

    Science.gov (United States)

    Rajender, Gone; Choudhury, Biswajit; Giri, P. K.

    2017-09-01

    This work spotlights the development of a plasmonic photocatalyst showing surface plasmon induced enhanced visible light photocatalytic (PC) performance. Plasmonic Au nanoparticles (NPs) are decorated over the hybrid nanosystem of graphitic carbon nitride (GCN) and graphene quantum dots (GQD) by citrate reduction method. Surface plasmon resonance (SPR) induced enhancement of Raman G and 2D band intensity is encountered on excitation of the Plasmonic hybrid at 514.5 nm, which is near to the 532 nm absorption band of Au NPs. Time-resolved photoluminescence and XPS studies show charge transfer interaction between GQD-GCN and Au NPs. Plasmonic hybrid exhibits an enhanced PC activity over the other catalysts in the photodegradation of methylene blue (MB) under visible light illumination. Plasmonic photocatalyst displays more than 6 fold enhancement in the photodecomposition rate of MB over GQD and nearly 2 fold improvement over GCN and GQD-GCN. GQD-GCN absorbs mostly in the near visible region and can be photoexcited by visible light of wavelength (λ ) carbon based hybrid photocatalyst for solar energy conversion.

  13. Biomimetic magnetic nanoparticles

    OpenAIRE

    Klem, Michael T.; Young, Mark; Douglas, Trevor

    2005-01-01

    Magnetic nanoparticles are of considerable interest because of their potential use in high-density memory devices, spintronics, and applications in diagnostic medicine. The conditions for synthesis of these materials are often complicated by their high reaction temperatures, costly reagents, and post-processing requirements. Practical applications of magnetic nanoparticles will require the development of alternate synthetic strategies that can overcome these impediments. Biomimetic approaches...

  14. Preparation and application of various nanoparticles in biology and medicine

    OpenAIRE

    Vardan Gasparyan

    2013-01-01

    The present paper considers prospects for application of various nanoparticles in biology and medicine. Here are presented data on preparation of gold and silver nanoparticles, and effects of shape of these nanoparticles on their optical properties. Application of these nanoparticles in diagnostics, for drug delivery and therapy, and preparation of magnetic nanoparticles from iron and cobalt salts are also discussed. Application of these nanoparticles as magnetic resonance imaging (MRI) contr...

  15. Gold nanoparticles for tumour detection and treatment

    NARCIS (Netherlands)

    Hartsuiker, Liesbeth; Petersen, W.; Petersen, Wilhelmina; Jose, J.; Jose, J.; van Es, P.; van Es, Peter; Lenferink, Aufrid T.M.; Poot, Andreas A.; Terstappen, Leonardus Wendelinus Mathias Marie; van Leeuwen, Ton; Manohar, Srirang; Otto, Cornelis

    2011-01-01

    The use of nanoparticles in biomedical applications is emerging rapidly. Recent developments have led to numerous studies of noble metal nanoparticles, down to the level of single molecule detection in living cells. The application of noble metal nanoparticles in diagnostics and treatment of early

  16. A New Insight into Growth Mechanism and Kinetics of Mesoporous Silica Nanoparticles by in Situ Small Angle X-ray Scattering.

    Science.gov (United States)

    Yi, Zhifeng; Dumée, Ludovic F; Garvey, Christopher J; Feng, Chunfang; She, Fenghua; Rookes, James E; Mudie, Stephen; Cahill, David M; Kong, Lingxue

    2015-08-04

    The growth mechanism and kinetics of mesoporous silica nanoparticles (MSNs) were investigated for the first time by using a synchrotron time-resolved small-angle X-ray scattering (SAXS) analysis. The synchrotron SAXS offers unsurpassed time resolution and the ability to detect structural changes of nanometer sized objects, which are beneficial for the understanding of the growth mechanism of small MSNs (∼20 nm). The Porod invariant was used to quantify the conversion of tetraethyl orthosilicate (TEOS) in silica during MSN formation, and the growth kinetics were investigated at different solution pH and temperature through calculating the scattering invariant as a function of reaction time. The growth of MSNs was found to be accelerated at high temperature and high pH, resulting in a higher rate of silica formation. Modeling SAXS data of micelles, where a well-defined electrostatic interaction is assumed, determines the size and shape of hexadecyltrimethylammonium bromide (CTAB) micelles before and after the addition of TEOS. The results suggested that the micelle size increases and the micelle shape changes from ellipsoid to spherical, which might be attributed to the solubilization of TEOS in the hydrophobic core of CTAB micelles. A new "swelling-shrinking" mechanism is proposed. The mechanism provides new insights into understanding MSN growth for the formation of functional mesoporous materials exhibiting controlled morphologies. The SAXS analyses were correlated to the structure of CTAB micelles and chemical reaction of TEOS. This study has provided critical information to an understanding of the growth kinetics and mechanism of MSNs.

  17. In situ synchrotron X-ray fluorescence mapping and speciation of CeO₂ and ZnO nanoparticles in soil cultivated soybean (Glycine max).

    Science.gov (United States)

    Hernandez-Viezcas, Jose A; Castillo-Michel, Hiram; Andrews, Joy Cooke; Cotte, Marine; Rico, Cyren; Peralta-Videa, Jose R; Ge, Yuan; Priester, John H; Holden, Patricia Ann; Gardea-Torresdey, Jorge L

    2013-02-26

    With the increased use of engineered nanomaterials such as ZnO and CeO₂ nanoparticles (NPs), these materials will inevitably be released into the environment, with unknown consequences. In addition, the potential storage of these NPs or their biotransformed products in edible/reproductive organs of crop plants can cause them to enter into the food chain and the next plant generation. Few reports thus far have addressed the entire life cycle of plants grown in NP-contaminated soil. Soybean ( Glycine max ) seeds were germinated and grown to full maturity in organic farm soil amended with either ZnO NPs at 500 mg/kg or CeO₂ NPs at 1000 mg/kg. At harvest, synchrotron μ-XRF and μ-XANES analyses were performed on soybean tissues, including pods, to determine the forms of Ce and Zn in NP-treated plants. The X-ray absorption spectroscopy studies showed no presence of ZnO NPs within tissues. However, μ-XANES data showed O-bound Zn, in a form resembling Zn-citrate, which could be an important Zn complex in the soybean grains. On the other hand, the synchrotron μ-XANES results showed that Ce remained mostly as CeO₂ NPs within the plant. The data also showed that a small percentage of Ce(IV), the oxidation state of Ce in CeO₂ NPs, was biotransformed to Ce(III). To our knowledge, this is the first report on the presence of CeO₂ and Zn compounds in the reproductive/edible portion of the soybean plant grown in farm soil with CeO₂ and ZnO NPs.

  18. Nanobiotechnology today: focus on nanoparticles

    Directory of Open Access Journals (Sweden)

    Soloviev Mikhail

    2007-12-01

    Full Text Available Abstract In the recent years the nanobiotechnology field and the Journal of Nanobiotechnology readership have witnessed an increase in interest towards the nanoparticles and their biological effects and applications. These include bottom-up and molecular self-assembly, biological effects of naked nanoparticles and nano-safety, drug encapsulation and nanotherapeutics, and novel nanoparticles for use in microscopy, imaging and diagnostics. This review highlights recent Journal of Nanobiotechnology publications in some of these areas http://www.jnanobiotechnology.com.

  19. SU-F-T-660: Evaluating the Benefit of Using Dual-Function Fiducial Markers for In-Situ Delivery of Radiosenistizing Gold Nanoparticles During Image-Guided Radiotherapy

    International Nuclear Information System (INIS)

    AlMansour, S; Chin, J; Sajo, E; Ngwa, W

    2016-01-01

    Purpose: Dual-function fiducials loaded with radiosensitizers, like gold nanoparticles (GNP), offer an innovative approach for ensuring geometric accuracy during image-guided radiotherapy (IGRT) and significantly increasing therapeutic efficacy due to controlled in-situ release of the radiosensitizers. This study retrospectively investigates the dosimetric benefit of using up to two such dual-function fiducial markers instead of traditional single function fiducials during IGRT. Methods: A computational code was developed to investigate the dosimetric benefit for 10 real patient tumor volumes of up to 6.5 cm diameter. The intra-tumoral space-time biodistribution of the GNP was modeled as in previous studies based on Fick’s second law. The corresponding dose-enhancement for each tumor voxel due to the GNP was also calculated for clinical 6MV beam configurations. Various loading concentrations (25–50 mg/g) were studied, as a function of GNP size, to determine potential for clinically significant dose enhancement. The time between initial implantation of dual-function fiducials to the beginning of radiotherapy was assumed to be 14 days as typical for many clinics. Results: A single dual-function fiducial could achieve at least a DEF of 1.2 for patients with tumors less than 1.4 cm diameter after 14 days. Replacing two single function fiducials with dual-function ones at the same locations achieved at least the required minimal DEF for tumors that are 2 cm diameter in 3 patients. The results also revealed dosimetrically better fiducial locations which could enable significant DEF when using one or two dual function fiducials. 2 nm sizes showed the most feasibility. Conclusion: The results highlight the potential of tumor sub-volume radiation boosting using GNP released from fiducials, and the ability to customize the DEF throughout the tumor by using two dual-function fiducials, varying the initial concentration and nanoparticle size. The results demonstrate

  20. SU-F-T-660: Evaluating the Benefit of Using Dual-Function Fiducial Markers for In-Situ Delivery of Radiosenistizing Gold Nanoparticles During Image-Guided Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    AlMansour, S; Chin, J; Sajo, E; Ngwa, W [University Massachusetts Lowell, Lowell, MA (United States)

    2016-06-15

    Purpose: Dual-function fiducials loaded with radiosensitizers, like gold nanoparticles (GNP), offer an innovative approach for ensuring geometric accuracy during image-guided radiotherapy (IGRT) and significantly increasing therapeutic efficacy due to controlled in-situ release of the radiosensitizers. This study retrospectively investigates the dosimetric benefit of using up to two such dual-function fiducial markers instead of traditional single function fiducials during IGRT. Methods: A computational code was developed to investigate the dosimetric benefit for 10 real patient tumor volumes of up to 6.5 cm diameter. The intra-tumoral space-time biodistribution of the GNP was modeled as in previous studies based on Fick’s second law. The corresponding dose-enhancement for each tumor voxel due to the GNP was also calculated for clinical 6MV beam configurations. Various loading concentrations (25–50 mg/g) were studied, as a function of GNP size, to determine potential for clinically significant dose enhancement. The time between initial implantation of dual-function fiducials to the beginning of radiotherapy was assumed to be 14 days as typical for many clinics. Results: A single dual-function fiducial could achieve at least a DEF of 1.2 for patients with tumors less than 1.4 cm diameter after 14 days. Replacing two single function fiducials with dual-function ones at the same locations achieved at least the required minimal DEF for tumors that are 2 cm diameter in 3 patients. The results also revealed dosimetrically better fiducial locations which could enable significant DEF when using one or two dual function fiducials. 2 nm sizes showed the most feasibility. Conclusion: The results highlight the potential of tumor sub-volume radiation boosting using GNP released from fiducials, and the ability to customize the DEF throughout the tumor by using two dual-function fiducials, varying the initial concentration and nanoparticle size. The results demonstrate

  1. In situ growth and phenyl functionalization of titania nanoparticles coating for solid-phase microextraction of ultraviolet filters in environmental water samples followed by high performance liquid chromatography-UV detection.

    Science.gov (United States)

    Li, Li; Guo, Ruibin; Li, Yi; Guo, Mei; Wang, Xuemei; Du, Xinzhen

    2015-03-31

    Based on TiO2-nanoparticles coating fabricated by a one-step anodization method on titanium wire substrate, a novel phenyl functionalized solid-phase microextraction (SPME) fiber coating was prepared by simple and rapid in situ chemical assembling technique between the fiber surface titanol groups and trichlorophenylsilane reaction. The as-fabricated fiber exhibited good extraction capability for some UV filters and was employed to determine the ultraviolet (UV) filters in combination with high performance liquid chromatography-UV detection (HPLC-UV). The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the developed method was applied to detect several UV filters at trace concentration levels with only 8 mL of sample volume. They were determined in the range from 0.005 to 25 μg L(-1) with detection limits (S/N=3) from 0.1 to 50 ng L(-1). The relative standard deviations (RSDs) for single fiber repeatability varied from 4.6 to 6.5% (n=5) and fiber-to-fiber reproducibility (n=5) ranged from 5.5 to 9.1%. The linear ranges spanned two-four magnitudes with correlation coefficients above 0.9990. Five real water samples including four Yellow River water samples and one rain water sample were determined sensitively with good recoveries ranging from 86.2 to 105.5%. The functionalized fiber coating performed good reproducible manner, high mechanical strength, good stability and long service life. Moreover, this study proposed an efficient sample pretreatment method for the determination of UV filters from environmental water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. In situ ultrasound-assisted preparation of Fe3O4@MnO2 core-shell nanoparticles integrated with ion co-precipitation for multielemental analysis by total reflection X-ray fluorescence

    Science.gov (United States)

    Nourbala-Tafti, Elaheh; Romero, Vanesa; Lavilla, Isela; Dadfarnia, Shayesteh; Bendicho, Carlos

    2017-05-01

    In this work, a new analytical approach based on in situ ultrasound-assisted preparation of manganese dioxide coated magnetite nanoparticles (Fe3O4@MnO2 NPs) was applied for extraction and preconcentration of Ni, Cu, Zn, Tl, Pb, Bi and Se. The Fe3O4@MnO2 core-shell nanocomposite was synthesized by application of high-intensity sonication to an aqueous reaction medium in the presence of the target analytes, which are trapped during NPs formation. In this way, synthesis of the nanosorbent and extraction can be simultaneously accomplished within only 30 s. After the extraction step, the resulting Fe3O4@MnO2 NPs enriched with the target analytes were separated by an external magnetic field, so that filtration or centrifugation steps were unnecessary. A 10 μL aliquot of the solid phase was deposited onto a sample carrier (quartz reflector) and directly analyzed by total-reflection X-ray fluorescence (TXRF) without the need for an elution step. A comprehensive characterization of the Fe3O4@MnO2 NPs was carried out by transmission electron microscopy and TXRF. Detection limits ranged from 0.19 to 0.98 μg L- 1 depending on the analyte. Enrichment factors in the range of 402-540 were obtained. The repeatability expressed as relative standard deviation was around 1.7% (N = 5). The accuracy of the proposed method was assessed by analyzing the certified reference material BCR®-610 (groundwater). An effective, simple, rapid and sensitive procedure for multielemental analysis of water samples was accomplished.

  3. Facile in situ synthesis of plasmonic nanoparticles-decorated g-C3N4/TiO2 heterojunction nanofibers and comparison study of their photosynergistic effects for efficient photocatalytic H2 evolution.

    Science.gov (United States)

    Wei, Xinbo; Shao, Changlu; Li, Xinghua; Lu, Na; Wang, Kexin; Zhang, Zhenyi; Liu, Yichun

    2016-06-07

    Ternary heterostructured nanofibers (NFs) consisting of plasmonic noble metal nanoparticles (Au, Ag, or Pt NPs), graphitic carbon nitride nanosheets (g-C3N4 NSs), and TiO2 NPs were synthesized in situ via a facile electrospinning technique combined with a subsequent thermal oxidation/reduction process. The thermal-reduced plasmonic NPs with sizes from 5 to 10 nm are dispersed uniformly into the heterojunctions of the NFs that are formed by thermal oxidation etching of exfoliated g-C3N4 NSs in the electrospun TiO2 nanofibrous matrix, as evidenced by microscopic and electronic structure analyses. In comparison to single-component photocatalysts, such as g-C3N4 NSs or TiO2 NFs, these ternary heterostructures exhibit significantly high photocatalytic activity for H2 evolution under simulated sunlight irradiation. The enhanced photoactivities are attributed to the strong photosynergistic effect between the surface plasmon resonance (SPR) and the heterojunction interface sensitization, which results in the improvement of charge-carrier generation and separation in the ternary heterostructured NFs. Further investigations indicate that coupling heterojunction sensitization on the g-C3N4/TiO2 interface with Ag SPR effects by plasmonic resonant energy transfer is the optimal strategy for synergistically improving the charge-carrier kinetics to achieve highly efficient photocatalytic H2 evolution. It is believed that our present study offers a promising method for the rational integration of multi-component photocatalytic systems that can realize high photocatalytic performances for use in solar-to-fuel conversion.

  4. Magnetic Iron Oxide Nanoparticles and a Polydiacetylene Coating to Create a Biocompatible and Stable Molecule for Use in Cancer Diagnostics and Early Detection in Molecular Medicine

    Science.gov (United States)

    Bhatnagar, Shweta

    Earlier cancer detection and diagnosis is essential to prevent cancer mortality in nanomedicine and nanotechnology. Fluorescence and magnetic signals provide a way for earlier detection through imaging systems. Magnetic iron oxide nanoparticles have a superparamagnetism feature that allows them to act as contrast agents that can be detected through a magnetic resonance imaging system. These iron oxide cores have a polymer coating around them to provide stability, prevent aggregation, and allow for biocompatibility within the body. In addition, these functional coatings can have ligands and peptides for detection and therapy purposes. One functional coating is a polydiacetylene coating due to its chromatic and optical properties. When polymerized, it has the ability to change color in the visible spectrum to blue (not a fluorescent signal) and when heated, it changes to a red color (fluorescent signal). This way a strong and stable layer is formed around the iron oxide cores. These coatings are placed on the iron cores using a modified dual solvent exchange method, in which DMSO is slowly replaced by water without the use of organic solvents previous used. In addition, these nanoparticles can then be PEGylated, which provides a more stable and water soluble compound in aqueous solutions. Measurements can be taken through dynamic light scattering for size distributions and zeta potential and the Nanodrop for absorbance. Ideal sizes are about 30 nm for MNPs. Moreover, for future directions, there can be more molecules attached to the coated layers to use for molecular detection and analysis.

  5. Gold Nanoparticle Mediated Phototherapy for Cancer

    International Nuclear Information System (INIS)

    Yao, C.; Zhang, L.; Wang, J.; He, Y.; Xin, J.; Wang, S.; Xu, H.; Zhang, Z.

    2016-01-01

    Gold nanoparticles exhibit very unique physiochemical and optical properties, which now are extensively studied in range of medical diagnostic and therapeutic applications. In particular, gold nanoparticles show promise in the advancement of cancer treatments. This review will provide insights into the four different cancer treatments such as photothermal therapy, gold nanoparticle-aided photodynamic therapy, gold nanoparticle-aided radiation therapy, and their use as drug carrier. We also discuss the mechanism of every method and the adverse effects and its limitations

  6. Functional modification of Nylon fabrics based on noble metal nanoparticles

    Science.gov (United States)

    Lin, Xia; Zou, Fan; Chen, Xinzhu; Tang, Bin

    2017-09-01

    In situ synthesis of gold nanoparticles was realized on Nylon fabrics through heat treatment with assistance of citrate. The synthesized gold nanoparticles imparted bright colors to Nylon fabrics due to its localized surface plasmon resonance (LSPR) features. Optical properties of the treated fabrics were analyzed by recording color strength (K/S) curves of fabrics. Scanning electron microscopy (SEM) was employed to observe the surface morphologies of Nylon fabrics with gold nanoparticles. The influence of pH value on the in situ synthesis of gold nanoparticles was discussed. Moreover, the coloration with gold nanoparticles improved the UV protection of Nylon fabrics.

  7. Synthesis of silver nanoparticles by sophorolipids: Effect of ...

    Indian Academy of Sciences (India)

    We report in situ synthesis of silver nanoparticles using biosurfactants called sophorolipids as reducing and capping agents. We further study the effect of temperature and the structure of sophorolipid on the size of silver nanoparticles obtained. The silver nanoparticles were characterized by UVvisible, transmission electron ...

  8. Synthesis of silver nanoparticles by sophorolipids: Effect of ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. We report in situ synthesis of silver nanoparticles using biosurfactants called sophorolipids as reducing and capping agents. We further study the effect of temperature and the structure of sophoro- lipid on the size of silver nanoparticles obtained. The silver nanoparticles were characterized by UV- visible ...

  9. [Cytology in uropathological diagnostics].

    Science.gov (United States)

    Gaisa, N T; Lindemann-Docter, K

    2015-11-01

    Cytology in uropathological diagnostics is mainly performed for oncological purposes. The assessment of malignancy by urothelial cell morphology is therefore decisive; however, cytology is only sensitive enough to detect high-grade tumor cells and the different low-grade tumors cannot be reliably diagnosed. Thus, the four-tier classification system of cytological findings (i.e. negative, atypical cells but significance uncertain, suspicious and positive) refers to high-grade tumor cells only. Furthermore, for valid cytological diagnostics not only the cytological specimen but also clinical information on cystoscopy findings and, if applicable, a biopsy should be evaluated together. In difficult differential diagnostic settings, e.g. differentiation between reactive versus neoplastic atypia or difficult to access lesions in the upper urinary tract, additional fluorescence in situ hybridization of cytological preparations might be helpful. At the moment there are no indications for further immunocytology or additional biomarker tests.

  10. In situ SU-8 silver nanocomposites

    Directory of Open Access Journals (Sweden)

    Søren V. Fischer

    2015-07-01

    Full Text Available Nanocomposite materials containing metal nanoparticles are of considerable interest in photonics and optoelectronics applications. However, device fabrication of such materials always encounters the challenge of incorporation of preformed nanoparticles into photoresist materials. As a solution to this problem, an easy new method of fabricating silver nanocomposites by an in situ reduction of precursors within the epoxy-based photoresist SU-8 has been developed. AgNO3 dissolved in acetonitrile and mixed with the epoxy-based photoresist SU-8 forms silver nanoparticles primarily during the pre- and post-exposure soft bake steps at 95 °C. A further high-temperature treatment at 300 °C resulted in the formation of densely homogeneously distributed silver nanoparticles in the photoresist matrix. No particle growth or agglomeration of nanoparticles is observed at this point. The reported new in situ silver nanocomposite materials can be spin coated as homogeneous thin films and structured by using UV lithography. A resolution of 5 µm is achieved in the lithographic process. The UV exposure time is found to be independent of the nanoparticle concentration. The fabricated silver nanocomposites exhibit high plasmonic responses suitable for the development of new optoelectronic and optical sensing devices.

  11. Diagnostic Magnetic Resonance Imaging of Atherosclerosis in Apolipoprotein E Knockout Mouse Model Using Macrophage-Targeted Gadolinium-Containing Synthetic Lipopeptide Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Zu T Shen

    Full Text Available Cardiovascular disease is the leading cause of death in Western cultures. The vast majority of cardiovascular events, including stroke and myocardial infarction, result from the rupture of vulnerable atherosclerotic plaques, which are characterized by high and active macrophage content. Current imaging modalities including magnetic resonance imaging (MRI aim to characterize anatomic and structural features of plaques rather than their content. Previously, we reported that macrophage-targeted delivery of gadolinium (Gd-based contrast agent (GBCA-HDL using high density lipoproteins (HDL-like particles significantly enhances the detection of plaques in an apolipoprotein (apo E knockout (KO mouse model, with an atherosclerotic wall/muscle normalized enhancement ratio (NER of 120% achieved. These particles are comprised of lipids and synthetic peptide fragments of the major protein of HDL, apo A-I, that contain a naturally occurring modification which targets the particles to macrophages. Targeted delivery minimizes the Gd dose and thus reduces the adverse effects of Gd. The aims of the current study were to test whether varying the GBCA-HDL particle shape and composition can further enhance atherosclerotic plaque MRI and control organ clearance of these agents. We show that the optimized GBCA-HDL particles are efficiently delivered intracellularly to and uptaken by both J774 macrophages in vitro and more importantly, by intraplaque macrophages in vivo, as evidenced by NER up to 160% and higher. This suggests high diagnostic power of our GBCA-HDL particles in the detection of vulnerable atherosclerotic plaques. Further, in contrast to discoidal, spherical GBCA-HDL exhibit hepatic clearance, which could further diminish adverse renal effects of Gd. Finally, activated macrophages are reliable indicators of any inflamed tissues and are implicated in other areas of unmet clinical need such as rheumatoid arthritis, sepsis and cancer, suggesting the

  12. In situ SU-8 silver nanocomposites

    DEFF Research Database (Denmark)

    Fischer, Søren Vang; Uthuppu, Basil; Jakobsen, Mogens Havsteen

    2015-01-01

    Nanocomposite materials containing metal nanoparticles are of considerable interest in photonics and optoelectronics applications. However, device fabrication of such materials always encounters the challenge of incorporation of preformed nanoparticles into photoresist materials. As a solution...... to this problem, an easy new method of fabricating silver nanocomposites by an in situ reduction of precursors within the epoxy-based photoresist SU-8 has been developed. AgNO3 dissolved in acetonitrile and mixed with the epoxy-based photoresist SU-8 forms silver nanoparticles primarily during the pre- and post...... silver nanocomposite materials can be spin coated as homogeneous thin films and structured by using UV lithography. A resolution of 5 mu m is achieved in the lithographic process. The UV exposure time is found to be independent of the nanoparticle concentration. The fabricated silver nanocomposites...

  13. Use of Complementary Approaches to Imaging Biomolecules and Endogenous and Exogenous Trace Elements and Nanoparticles in Biological Samples

    Science.gov (United States)

    Brown, Koshonna Dinettia

    X-ray Fluorescence Microscopy (XFM) is a useful technique for study of biological samples. XFM was used to map and quantify endogenous biological elements as well as exogenous materials in biological samples, such as the distribution of titanium dioxide (TiO2) nanoparticles. TiO 2 nanoparticles are produced for many different purposes, including development of therapeutic and diagnostic particles for cancer detection and treatment, drug delivery, and induction of DNA breaks. Delivery of such nanoparticles can be targeted to specific cells and subcellular structures. In this work, we develop two novel approaches to stain TiO2 nanoparticles for optical microscopy and to confirm that staining by XFM. The first approach utilizes fluorescent biotin and fluorescent streptavidin to label the nanoparticles before and after cellular uptake; the second approach is based on the copper-catalyzed azide-alkyne cycloaddition, the so-called CLICK chemistry, for labeling of azide conjugated TiO2 nanoparticles with "clickable" dyes such as alkyne Alexa Fluor dyes with a high fluorescent yield. To confirm that the optical fluorescence signals of nanoparticles stained in situ match the distribution of the Ti element, we used high resolution synchrotron X-Ray Fluorescence Microscopy (XFM) using the Bionanoprobe instrument at the Advanced Photon Source at Argonne National Laboratory. Titanium-specific X-ray fluorescence showed excellent overlap with the location of Alexa Fluor optical fluorescence detected by confocal microscopy. In this work XFM was also used to investigate native elemental differences between two different types of head and neck cancer, one associated with human papilloma virus infection, the other virus free. Future work may see a cross between these themes, for example, exploration of TiO2 nanoparticles as anticancer treatment for these two different types of head and neck cancer.

  14. Immunological properties of gold nanoparticles

    OpenAIRE

    Dykman, Lev A.; Khlebtsov, Nikolai G.

    2016-01-01

    In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be...

  15. In situ

    Science.gov (United States)

    Chamlagain, Bhawani; Sugito, Tessa A; Deptula, Paulina; Edelmann, Minnamari; Kariluoto, Susanna; Varmanen, Pekka; Piironen, Vieno

    2018-01-01

    The in situ production of active vitamin B12 was investigated in aqueous cereal-based matrices with three strains of food-grade Propionibacterium freudenreichii . Matrices prepared from malted barley flour (33% w/v; BM), barley flour (6%; BF), and wheat aleurone (15%; AM) were fermented. The effect of cobalt and the lower ligand 5,6-dimethylbenzimidazole (DMBI) or its natural precursors (riboflavin and nicotinamide) on active B12 production was evaluated. Active B12 production was confirmed by UHPLC-UV-MS analysis. A B12 content of 12-37 μg·kg -1 was produced in BM; this content increased 10-fold with cobalt and reached 940-1,480 μg·kg -1 with both cobalt and DMBI. With riboflavin and nicotinamide, B12 production in cobalt-supplemented BM increased to 712 μg·kg -1 . Approximately, 10 μg·kg -1 was achieved in BF and AM and was increased to 80 μg·kg -1 in BF and 260 μg·kg -1 in AM with cobalt and DMBI. The UHPLC and microbiological assay (MBA) results agreed when both cobalt and DMBI or riboflavin and nicotinamide were supplemented. However, MBA gave ca. 20%-40% higher results in BM and AM supplemented with cobalt, indicating the presence of human inactive analogues, such as pseudovitamin B12. This study demonstrates that cereal products can be naturally fortified with active B12 to a nutritionally relevant level by fermenting with P. freudenreichii .

  16. Immunological properties of gold nanoparticles.

    Science.gov (United States)

    Dykman, Lev A; Khlebtsov, Nikolai G

    2017-03-01

    In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be properly fabricated to deliver the cargo into the targeted cells through effective endocytosis. In this review, we discuss recent progress in understanding the selective penetration of gold nanoparticles into immune cells. The interaction of gold nanoparticles with immune cell receptors is discussed. As distinct from other published reviews, we present a summary of the immunological properties of gold nanoparticles. This review also summarizes what is known about the application of gold nanoparticles as an antigen carrier and adjuvant in immunization for the preparation of antibodies in vivo . For each of the above topics, the basic principles, recent advances, and current challenges are discussed. Thus, this review presents a detailed analysis of data on interaction of gold nanoparticles with immune cells. Emphasis is placed on the systematization of data over production of antibodies by using gold nanoparticles and adjuvant properties of gold nanoparticles. Specifically, we start our discussion with current data on interaction of various gold nanoparticles with immune cells. The next section describes existing technologies to improve production of antibodies in vivo by using gold nanoparticles conjugated with specific ligands. Finally, we describe what is known about adjuvant properties of bare gold or functionalized nanoparticles. In the Conclusion section, we present a short summary of reported data and some challenges and perspectives.

  17. Evaluation of nanoparticle immunotoxicity

    Science.gov (United States)

    Dobrovolskaia, Marina A.; Germolec, Dori R.; Weaver, James L.

    2009-07-01

    The pharmaceutical industry is developing increasing numbers of drugs and diagnostics based on nanoparticles, and evaluating the immune response to these diverse formulations has become a challenge for scientists and regulatory agencies alike. An international panel of scientists and representatives from various agencies and companies reviewed the imitations of current tests at a workshop held at the National Cancer Institute in Frederick, Maryland. This article outlines practical strategies for identifying and controlling interferences in common evaluation methods and the implications for regulation.

  18. Hybrid organic/inorganic silicon-based sol-gel materials: A modification for scale-up conversion in anti-corrosion applications, and, A modification for in-situ synthesis of cadmium sulfide nanoparticles in optical applications

    Science.gov (United States)

    Tran, Tuan Thanh

    Sol-gel chemistry has been used for many years in many applications. In this thesis, an application for anti-corrosion product and a method of using sol-gel chemistry in synthesis of CdS nanoparticles are introduced. Strategies for industrial synthesis of this anti-corrosion material are also discussed. In addition, fillers and corrosion inhibitors are successfully introduced into these anti-corrosion materials to decrease producing costs while still maintaining its anti-corrosion properties. For the CdS nanopartic1es, we were able to synthesize nanoparticles with a narrow size distribution. These CdS nanopartic1es are bound tightly to the host network and have an average diameter of 1.79 nanometers. Keywords: Sol-gel, Anti-corrosion, Fillers, Inhibitors, Paint, Nanoparticles.

  19. Diagnostic laparoscopy

    Science.gov (United States)

    ... cavity. These complications could lead to immediate open surgery ( laparotomy ). Diagnostic laparoscopy may not be possible if you have a swollen bowel, fluid in the abdomen (ascites), or you have had a past surgery.

  20. Companion diagnostics

    DEFF Research Database (Denmark)

    Jørgensen, Jan Trøst; Hersom, Maria

    2016-01-01

    . Despite having discussed personalized medicine for more than a decade, we still see that most drug prescriptions for severe chronic diseases are largely based on 'trial and error' and not on solid biomarker data. However, with the advance of molecular diagnostics and a subsequent increased understanding...... of disease mechanisms, things are slowly changing. Within the last few years, we have seen an increasing number of predictive biomarker assays being developed to guide the use of targeted cancer drugs. This type of assay is called companion diagnostics and is developed in parallel to the drug using the drug-diagnostic...... co-development model. The development of companion diagnostics is a relatively new discipline and in this review, different aspects will be discussed including clinical and regulatory issues. Furthermore, examples of drugs, such as the ALK and PD-1/PD-L1 inhibitors, that have been approved recently...

  1. Multifunctional Nanoparticles for Drug Delivery Applications Imaging, Targeting, and Delivery

    CERN Document Server

    Prud'homme, Robert

    2012-01-01

    This book clearly demonstrates the progression of nanoparticle therapeutics from basic research to applications. Unlike other books covering nanoparticles used in medical applications, Multifunctional Nanoparticles for Drug Delivery Applications presents the medical challenges that can be reduced or even overcome by recent advances in nanoscale drug delivery. Each chapter highlights recent progress in the design and engineering of select multifunctional nanoparticles with topics covering targeting, imaging, delivery, diagnostics, and therapy.

  2. Fluorescent and chromogenic in situ hybridization of CEN17q as a potent useful diagnostic marker for Birt-Hogg-Dubé syndrome-associated chromophobe renal cell carcinomas.

    Science.gov (United States)

    Kato, Ikuma; Iribe, Yasuhiro; Nagashima, Yoji; Kuroda, Naoto; Tanaka, Reiko; Nakatani, Yukio; Hasumi, Hisashi; Yao, Masahiro; Furuya, Mitsuko

    2016-06-01

    Birt-Hogg-Dubé syndrome (BHD) is a familial disorder associated with a germline mutation of FLCN that is a tumor suppressor gene. Patients with BHD have high risks for developing multiple renal cell carcinomas (RCCs). The frequent histological types are hybrid oncocytic/chromophobe tumors (HOCTs) and chromophobe RCCs. The morphology of HOCTs could alert pathologists to the possibility of BHD. On the other hand, chromophobe RCCs occurring in BHD patients demonstrate positive immunostaining for cytokeratin-7, CD82, and Ksp-cadherin similar to their sporadic counterparts. Highly reliable markers for BHD-associated chromophobe RCCs have not been identified. In the present study, we analyzed the state of chromosome 17 in 18 renal tumors composed of 8 chromophobe RCCs, 7 HOCTs, and 3 papillary RCCs obtained from BHD patients using fluorescent and chromogenic in situ hybridization probes for the centromeric region of chromosome 17 long arm. All chromophobe RCCs and HOCTs were disomic except for 1 chromophobe RCC that showed monosomy. On the other hand, 12 of 14 sporadic chromophobe RCCs were monosomic (P = .0008). The state of chromosomes 2 and 6 were also statistically different (P = .0074 and P = .0007, respectively). Three BHD-associated papillary RCCs demonstrated either trisomy (n = 2) or disomy (n = 1). Three of 5 sporadic papillary RCCs showed trisomy. The results indicate that fluorescent and chromogenic in situ hybridization of the centromeric region of chromosome 17 long arm should be a potent useful marker for chromophobe RCCs in patients who have not been diagnosed with BHD and thereby help to determine whether the cases should be considered for genetic testing. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. In situ TEM studies of carbon and gold nanostructures

    Science.gov (United States)

    Casillas Garcia, Gilberto

    Properties of matter change as structures go down in size to the nanoscale, creating new possibilities for creating new functional materials with better properties than the bulk. In situ TEM techniques were used to probe the properties of two different materials: atomic carbon chains and gold nanoparticles. Carbon chains were synthesized by in situ TEM electron beam irradiation from few-layers-graphene (FLG) flakes. Several chains up to 5 nm long were observed. Aberration corrected TEM confirmed the dimerization of the linear chain as predicted by Peierls. Moreover, it was observed that two linear carbon chains can cross-bond every 9 atoms, and it was confirmed by DFT calculations. Five-fold nanoparticles are not supposed to be stable beyond 5 nm size. Here, decahedra with high index facets in the order of 300 nm were studied by TEM. It was found that the high index facets were only stable by adding a capping agent, otherwise, smooth edges were observed. In this case, a (5x1) hexagonal surface reconstruction was observed on the {001} surfaces, with the hexagonal strings along a [110] and a [410] direction. Additionally, mechanical properties of gold nanoparticles, with and without twin boundaries, under 100 nm were measured by in situ TEM compression experiments. All of the nanoparticles presented yield strengths in the order of GPa. Multi twinned nanoparticles were found to be more malleable, reaching real compressing strains of 100 %, while the single crystal nanoparticle presented less plastic flow. Molecular dynamics simulations revealed that the twin boundaries contribute to the malleability of the nanoparticles, at the same time it provides a mechanism to stop dislocations, hence, strain hardening the nanoparticle at later stages of compression. Finally, the behavior of a single grain boundary was studied by in situ TEM manipulation of nanoparticles. A liquid-like behavior of a grain boundary is observed after two 40 nm gold nanoparticles are brought to

  4. Ostwald ripening in a Pt/SiO2 model catalyst studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chorkendorff, Ib; Dahl, Søren

    2011-01-01

    by the Ostwald ripening mechanism. The in situ TEM images also provide information about the temporal evolution of the Pt particle size distribution and of the growth or decay of the individual nanoparticles. The observed Pt nanoparticle changes compare well with predictions made by mean-field kinetic models...... for ripening, but deviations are revealed for the time-evolution for the individual nanoparticles. A better description of the individual nanoparticle ripening is obtained by kinetic models that include local correlations between neighboring nanoparticles in the atom-exchange process....

  5. Diagnostic development

    International Nuclear Information System (INIS)

    Barnett, C.F.; Brisson, D.A.; Greco, S.E.

    1978-01-01

    During the past year the far-infrared or submillimeter diagnostic research program resulted in three major developments: (1) an optically pumped 0.385-μm D 2 O-laser oscillator-amplifier system was operated at a power level of 1 MW with a line width of less than 50 MHz; (2) a conical Pyrex submillimeter laser beam dump with a retention efficiency greater than 10 4 was developed for the ion temperature Thompson scattering experiment; and (3) a new diagnostic technique was developed that makes use of the Faraday rotation of a modulated submillimeter laser beam to determine plasma current profile. Measurements of the asymmetric distortion of the H/sub α/ (6563 A) spectral line profile show that the effective toroidal drift velocity, dv/sub two vertical bars i/dT/sub i/, may be used as an indicator of plasma quality and as a complement to other ion temperature diagnostics

  6. Fungal diagnostics.

    Science.gov (United States)

    Kozel, Thomas R; Wickes, Brian

    2014-04-01

    Early diagnosis of fungal infection is critical to effective treatment. There are many impediments to diagnosis such as a diminishing number of clinical mycologists, cost, time to result, and requirements for sensitivity and specificity. In addition, fungal diagnostics must meet the contrasting needs presented by the increasing diversity of fungi found in association with the use of immunosuppressive agents in countries with high levels of medical care and the need for diagnostics in resource-limited countries where large numbers of opportunistic infections occur in patients with AIDS. Traditional approaches to diagnosis include direct microscopic examination of clinical samples, histopathology, culture, and serology. Emerging technologies include molecular diagnostics and antigen detection in clinical samples. Innovative new technologies that use molecular and immunoassay platforms have the potential to meet the needs of both resource-rich and resource-limited clinical environments.

  7. In situ Remediation Technologies

    NARCIS (Netherlands)

    Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2011-01-01

    A summary of two decades of developments of In Situ remediation is presented in this chapter. The basic principles of In Situ technology application are addressed, such as equilibrium relations between contaminant phases, factors controlling biological and geochemical processes, contaminant

  8. Stimuli-responsive liposome-nanoparticle assemblies.

    Science.gov (United States)

    Preiss, Matthew R; Bothun, Geoffrey D

    2011-08-01

    Nanoscale assemblies are needed that achieve multiple therapeutic objectives, including cellular targeting, imaging, diagnostics and drug delivery. These must exhibit high stability, bioavailability and biocompatibility, while maintaining or enhancing the inherent activity of the therapeutic cargo. Liposome-nanoparticle assemblies (LNAs) combine the demonstrated potential of liposome-based therapies, with functional nanoparticles. Specifically, LNAs can be used to concentrate and shield the nanoparticles and, in turn, stimuli-responsive nanoparticles that respond to external fields can be used to control liposomal release. The ability to design LNAs via nanoparticle encapsulation, decoration or bilayer-embedment offers a range of configurations with different structures and functions. This paper reviews the current state of research and understanding of the design, characterization and performance of LNAs. A brief overview is provided on liposomes and nanoparticles for therapeutic applications, followed by a discussion of the opportunities and challenges associated with combining the two in a single assembly to achieve controlled release via light or radiofrequency stimuli. LNAs offer a unique opportunity to combine the therapeutic properties of liposomes and nanoparticles. Liposomes act to concentrate small nanoparticles and shield nanoparticles from the immune system, while the nanoparticle can be used to initiate and control drug release when exposed to external stimuli. These properties provide a platform to achieve nanoparticle-controlled liposomal release. LNA design and application are still in infancy. Research concentrating on the relationships among LNA structure, function and performance is essential for the future clinical use of LNAs.

  9. Cathodoluminescence and phase-change functionality of metallic nanoparticles

    OpenAIRE

    Denisyuk, A.I.

    2009-01-01

    Nanoscale resolution cathodoluminescence (CL) has been used to demonstrate and investigate the functionality of nanoparticle-based components for future nanophotonic phase-change memory and optical antenna applications. An integrated experimental system based on a scanning electron microscope was developed for the fabrication and in situ characterization of nanoparticles. It was equipped with an atomic beam source for gallium nanoparticle growth, a liquid-nitrogen-cooled cryostat to control s...

  10. In Situ Confined Growth Based on a Self-Templating Reduction Strategy of Highly Dispersed Ni Nanoparticles in Hierarchical Yolk-Shell Fe@SiO2Structures as Efficient Catalysts.

    Science.gov (United States)

    Jiao, Jiao; Wang, Haiyan; Guo, Wanchun; Li, Ruifei; Tian, Kesong; Xu, Zhaopeng; Jia, Yin; Wu, Yuehao; Cao, Ling

    2016-12-19

    Ni-based magnetic catalysts exhibit moderate activity, low cost, and magnetic reusability in hydrogenation reactions. However, Ni nanoparticles anchored on magnetic supports commonly suffer from undesirable agglomeration during catalytic reactions due to the relatively weak affinity of the magnetic support for the Ni nanoparticles. A hierarchical yolk-shell Fe@SiO 2 /Ni catalyst, with an inner movable Fe core and an ultrathin SiO 2 /Ni shell composed of nanosheets, was synthesized in a self-templating reduction strategy with a hierarchical yolk-shell Fe 3 O 4 @nickel silicate nanocomposite as the precursor. The spatial confinement of highly dispersed Ni nanoparticles with a mean size of 4 nm within ultrathin SiO 2 nanosheets with a thickness of 2.6 nm not only prevented their agglomeration during catalytic transformations but also exposed the abundant active Ni sites to reactants. Moreover, the large inner cavities and interlayer spaces between the assembled ultrathin SiO 2 /Ni nanosheets provided suitable mesoporous channels for diffusion of the reactants towards the active sites. As expected, the Fe@SiO 2 /Ni catalyst displayed high activity, high stability, and magnetic recoverability for the reduction of nitroaromatic compounds. In particular, the Ni-based catalyst in the conversion of 4-nitroamine maintained a rate of over 98 % and preserved the initial yolk-shell structure without any obvious aggregation of Ni nanoparticles after ten catalytic cycles, which confirmed the high structural stability of the Ni-based catalyst. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Direct monitoring of lipid transfer on exposure of citrem nanoparticles to an ethanol solution containing soybean phospholipids by combining synchrotron SAXS with microfluidics

    DEFF Research Database (Denmark)

    Khaliqi, K.; Ghazal, A.; Mat Azmi, Intan Diana

    2017-01-01

    Lipid exchange among citrem nanoparticles and an ethanol micellar solution containing soy phosphatidylcholine was investigated in situ by coupling small angle X-ray scattering with a microfluidic device. The produced soy phosphatidylcholine/citrem nanoparticles have great potential...

  12. Diagnostic formulation

    OpenAIRE

    Kuruvilla, K.; Kuruvilla, Anju

    2010-01-01

    Writing a ?Diagnostic Formulation? is a skill expected of candidates in the post-graduate examinations in psychiatry in most universities in India. However there is ambiguity regarding what the term means and how it should be written. This article is an attempt to provide some guidelines on this topic.

  13. Quantitative analysis of gold and carbon nanoparticles in mammalian cells by flow cytometry light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Gang [Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences (China); Liu, Naicheng; Wang, Zhenheng [Nanjing University, Department of Orthopedics, Jinling Hospital, School of Medicine (China); Shi, Tongguo; Gan, Jingjing; Wang, Zhenzhen; Zhang, Junfeng, E-mail: jfzhang@nju.edu.cn [Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences (China)

    2017-02-15

    Nanoparticle-based applications for diagnostics and therapeutics have been extensively studied. These applications require a profound understanding of the fate of nanoparticles (NPs) in cellular environments. However, until now, few analytical methods are available and most of them rely on fluorescent properties or special elements of NPs; therefore, for NPs without observable optical properties or special elements, the existing methods are hardly applicable. In this study, we introduce a flow cytometry light scattering (FCLS)-based approach that quantifies in situ NPs accurately in mammalian cells. Continuous cells of heterogeneous human epithelial colorectal adenocarcinoma (Caco-2 cells), mouse peritoneal macrophages (MPM), and human adenocarcinomic alveolar basal epithelia (A549 cells) were cultured with NPs with certain concentrations and size. The intensity of the flow cytometric side scattered light, which indicates the quantity of NPs in the cells, was analyzed. The result shows an accurate size- and dose-dependent uptake of Au NPs (5, 30, 250 nm) in Caco-2 cells. The size- and dose- dependence of Au NPs (5, 30, 250 nm) and carbon NPs (50, 500 nm) in cells was validated by transmission electron microscope (TEM). This paper demonstrates the great potential of flow cytometry light scattering in the quantitative study of the size and dose effect on in situ metallic or non-metallic NPs in mammalian cells.

  14. Gold Nanoparticles Cytotoxicity

    Science.gov (United States)

    Mironava, Tatsiana

    Over the last two decades gold nanoparticles (AuNPs) have been used for many scientific applications and have attracted attention due to the specific chemical, electronic and optical size dependent properties that make them very promising agents in many fields such as medicine, imagine techniques and electronics. More specifically, biocompatible gold nanoparticles have a huge potential for use as the contrast augmentation agent in X-ray Computed Tomography and Photo Acoustic Tomography for early tumor diagnostic as well these nanoparticles are extensively researched for enhancing the targeted cancer treatment effectiveness such as photo-thermal and radiotherapy. In most biomedical applications biocompatible gold nanoparticles are labeled with specific tumor or other pathology targeting antibodies and used for site specific drug delivery. However, even though gold nanoparticles poses very high level of anti cancer properties, the question of their cytotoxicity ones they are released in normal tissue has to be researched. Moreover, the huge amount of industrially produced gold nanoparticles raises the question of these particles being a health hazard, since the penetration is fairly easy for the "nano" size substances. This study focuses on the effect of AuNPs on a human skin tissue, since it is fall in both categories -- the side effects for biomedical applications and industrial workers and users' exposure during production and handling. Therefore, in the present project, gold nanoparticles stabilized with the biocompatible agent citric acid were generated and characterized by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The cytotoxic effect of AuNPs release to healthy skin tissue was modeled on 3 different cell types: human keratinocytes, human dermal fibroblasts, and human adipose derived stromal (ADS) cells. The AuNPs localization inside the cell was found to be cell type dependent. Overall cytotoxicity was found to be dependent

  15. Polymer Stabilized Nanosuspensions Formed via Flash Nanoprecipitation: Nanoparticle Formation, Formulation, and Stability

    Science.gov (United States)

    Zhu, ZhengXi

    Nanoparticles loaded with hydrophobic components (e.g., active pharmaceutical ingredients, medical diagnostic agents, nutritional or personal care chemicals, catalysts, dyes/pigments, and substances with exceptional magnetic/optical/electronic/thermal properties) have tremendous industrial applications. The common desire is to efficiently generate nanoparticles with a desired size, size distribution, and size stability. Recently, Flash NanoPrecipition (FNP) technique with a fast, continuous, and easily scalable process has been developed to efficiently generate hydrophobe-loaded nanoparticles. This dissertation extended this technique, optimized process conditions and material formulations, and gave new insights into the mechanism and kinetics of nanoparticle formation. This dissertation demonstrated successful generation of spherical beta-carotene nanoparticles with an average diameter of 50--100 nm (90 wt% nanoparticles below 200 nm), good size stability (maintained an average diameter below 200 nm for at least one week in saline), and much higher loading (80--90 wt%) than traditional carriers, such as micelles and polymersomes (typically FNP were proposed. To optimize the material formulations, either polyelectrolytes (i.e., epsilon-polylysine, branched and linear poly(ethylene imine), and chitosan) or amphiphilic diblock copolymers (i.e., polystyrene-b-poly(ethylene glycol) (PS-b-PEG), polycarprolactone-b-poly(ethylene glycol) (PCL-b-PEG), poly(lactic acid)-b-poly(ethylene glycol) (PLA-b-PEG), and poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-b-PEG)) were selectively screened to study the nanoparticle size, distribution, and stability. The effect of the molecular weight of the polymers and pH were also studied. Chitosan and PLGA-b-PEG best stabilized the beta-carotene nanoparticles. Solubility of the hydrophobic drug solute in the aqueous mixture was considered to dominate the nanoparticle stability (i.e., size and morphology) in terms of Ostwald

  16. Mechanical and dynamic characteristics of encapsulated microbubbles coupled by magnetic nanoparticles as multifunctional imaging and drug delivery agents

    Science.gov (United States)

    Guo, Gepu; Lu, Lu; Yin, Leilei; Tu, Juan; Guo, Xiasheng; Wu, Junru; Xu, Di; Zhang, Dong

    2014-11-01

    Development of magnetic encapsulated microbubble agents that can integrate multiple diagnostic and therapeutic functions is a key focus in both biomedical engineering and nanotechnology and one which will have far-reaching impact on medical diagnosis and therapies. However, properly designing multifunctional agents that can satisfy particular diagnostic/therapeutic requirements has been recognized as rather challenging, because there is a lack of comprehensive understanding of how the integration of magnetic nanoparticles to microbubble encapsulating shells affects their mechanical properties and dynamic performance in ultrasound imaging and drug delivery. Here, a multifunctional imaging contrast and in-situ gene/drug delivery agent was synthesized by coupling super paramagnetic iron oxide nanoparticles (SPIOs) into albumin-shelled microbubbles. Systematical studies were performed to investigate the SPIO-concentration-dependence of microbubble mechanical properties, acoustic scattering response, inertial cavitation activity and ultrasound-facilitated gene transfection effect. These demonstrated that, with the increasing SPIO concentration, the microbubble mean diameter and shell stiffness increased and ultrasound scattering response and inertial cavitation activity could be significantly enhanced. However, an optimized ultrasound-facilitated vascular endothelial growth factor transfection outcome would be achieved by adopting magnetic albumin-shelled microbubbles with an appropriate SPIO concentration of 114.7 µg ml-1. The current results would provide helpful guidance for future development of multifunctional agents and further optimization of their diagnostic/therapeutic performance in clinic.

  17. Highly biocompatible and water-dispersible, amine functionalized magnetite nanoparticles, prepared by a low temperature, air-assisted polyol process: a new platform for bio-separation and diagnostics

    Science.gov (United States)

    Das, Manasmita; Dhak, Prasanta; Gupta, Satyajit; Mishra, Debasish; Maiti, Tapas K.; Basak, Amit; Pramanik, Panchanan

    2010-03-01

    A low temperature polyol process, based on glycolaldehyde mediated partial reduction of FeCl3·6H2O at 120 °C in the presence of sodium acetate as an alkali source and 2, 2'-(ethylenedioxy)-bis-(ethylamine) as an electrostatic stabilizer has been used for the gram-scale preparation of biocompatible, water-dispersible, amine functionalized magnetite nanoparticles (MNPs) with an average diameter of 6 ± 0.75 nm. With a reasonably high magnetization (37.8 e.m.u.) and amine groups on the outer surface of the nanoparticles, we demonstrated the magnetic separation and concentration implications of these ultrasmall particles in immunoassay. MRI studies indicated that these nanoparticles had the desired relaxivity for T2 contrast enhancement in vivo. In vitro biocompatibility, cell uptake and MR imaging studies established that these nanoparticles were safe in clinical dosages and by virtue of their ultrasmall sizes and positively charged surfaces could be easily internalized by cancer cells. All these positive attributes make these functional nanoparticles a promising platform for further in vitro and in vivo evaluations.

  18. Highly biocompatible and water-dispersible, amine functionalized magnetite nanoparticles, prepared by a low temperature, air-assisted polyol process: a new platform for bio-separation and diagnostics.

    Science.gov (United States)

    Das, Manasmita; Dhak, Prasanta; Gupta, Satyajit; Mishra, Debasish; Maiti, Tapas K; Basak, Amit; Pramanik, Panchanan

    2010-03-26

    A low temperature polyol process, based on glycolaldehyde mediated partial reduction of FeCl(3).6H(2)O at 120 degrees C in the presence of sodium acetate as an alkali source and 2, 2(')-(ethylenedioxy)-bis-(ethylamine) as an electrostatic stabilizer has been used for the gram-scale preparation of biocompatible, water-dispersible, amine functionalized magnetite nanoparticles (MNPs) with an average diameter of 6 +/- 0.75 nm. With a reasonably high magnetization (37.8 e.m.u.) and amine groups on the outer surface of the nanoparticles, we demonstrated the magnetic separation and concentration implications of these ultrasmall particles in immunoassay. MRI studies indicated that these nanoparticles had the desired relaxivity for T(2) contrast enhancement in vivo. In vitro biocompatibility, cell uptake and MR imaging studies established that these nanoparticles were safe in clinical dosages and by virtue of their ultrasmall sizes and positively charged surfaces could be easily internalized by cancer cells. All these positive attributes make these functional nanoparticles a promising platform for further in vitro and in vivo evaluations.

  19. Highly biocompatible and water-dispersible, amine functionalized magnetite nanoparticles, prepared by a low temperature, air-assisted polyol process: a new platform for bio-separation and diagnostics

    International Nuclear Information System (INIS)

    Das, Manasmita; Dhak, Prasanta; Gupta, Satyajit; Basak, Amit; Pramanik, Panchanan; Mishra, Debasish; Maiti, Tapas K

    2010-01-01

    A low temperature polyol process, based on glycolaldehyde mediated partial reduction of FeCl 3 ·6H 2 O at 120 deg. C in the presence of sodium acetate as an alkali source and 2, 2 ' -(ethylenedioxy)-bis-(ethylamine) as an electrostatic stabilizer has been used for the gram-scale preparation of biocompatible, water-dispersible, amine functionalized magnetite nanoparticles (MNPs) with an average diameter of 6 ± 0.75 nm. With a reasonably high magnetization (37.8 e.m.u.) and amine groups on the outer surface of the nanoparticles, we demonstrated the magnetic separation and concentration implications of these ultrasmall particles in immunoassay. MRI studies indicated that these nanoparticles had the desired relaxivity for T 2 contrast enhancement in vivo. In vitro biocompatibility, cell uptake and MR imaging studies established that these nanoparticles were safe in clinical dosages and by virtue of their ultrasmall sizes and positively charged surfaces could be easily internalized by cancer cells. All these positive attributes make these functional nanoparticles a promising platform for further in vitro and in vivo evaluations.

  20. Nanoparticle growth in ethanol based plasmas

    Science.gov (United States)

    Labidi, S.; Lecas, T.; Kovacevic, E.; Berndt, J.; Gibert, T.; Mikikian, M.

    2018-01-01

    Nanoparticles are grown in a capacitively-coupled radio-frequency discharge (ccrf) in argon from the sputtering of a carbonaceous film deposited on the electrodes. This brown film was previously formed from the ethanol decomposition obtained in argon/ethanol plasmas. During the nanoparticle growth, optical emission spectroscopy reveals the evolution of some typical carbonaceous molecules. The nanoparticle formation also disturbs the plasma equilibrium and induces several plasma instabilities consisting in some cases in regular plasma rotation at very low frequencies. Once nanoparticles are large enough to be observed, they constitute a dense cloud trapped in between the electrode with one central or two symmetrical voids. Ex-situ analysis by scanning electron microscopy evidences that grown nanoparticles can have original surface stuctures.

  1. QCM-D study of nanoparticle interactions.

    Science.gov (United States)

    Chen, Qian; Xu, Shengming; Liu, Qingxia; Masliyah, Jacob; Xu, Zhenghe

    2016-07-01

    Quartz crystal microbalance with dissipation monitoring (QCM-D) has been proven to be a powerful research tool to investigate in situ interactions between nanoparticles and different functionalized surfaces in liquids. QCM-D can also be used to quantitatively determine adsorption kinetics of polymers, DNA and proteins from solutions on various substrate surfaces while providing insights into conformations of adsorbed molecules. This review aims to provide a comprehensive overview on various important applications of QCM-D, focusing on deposition of nanoparticles and attachment-detachment of nanoparticles on model membranes in complex fluid systems. We will first describe the working principle of QCM-D and DLVO theory pertinent to understanding nanoparticle deposition phenomena. The interactions between different nanoparticles and functionalized surfaces for different application areas are then critically reviewed. Finally, the potential applications of QCM-D in other important fields are proposed and knowledge gaps are identified. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. A bio-inspired approach for in situ synthesis of tunable adhesive

    International Nuclear Information System (INIS)

    Sun, Leming; Yi, Sijia; Wang, Yongzhong; Pan, Kang; Zhong, Qixin; Zhang, Mingjun

    2014-01-01

    Inspired by the strong adhesive produced by English ivy, this paper proposes an in situ synthesis approach for fabricating tunable nanoparticle enhanced adhesives. Special attention was given to tunable features of the adhesive produced by the biological process. Parameters that may be used to tune properties of the adhesive will be proposed. To illustrate and validate the proposed approach, an experimental platform was presented for fabricating tunable chitosan adhesive enhanced by Au nanoparticles synthesized in situ. This study contributes to a bio-inspired approach for in situ synthesis of tunable nanocomposite adhesives by mimicking the natural biological processes of ivy adhesive synthesis. (paper)

  3. Hydrogel nanoparticle based immunoassay

    Science.gov (United States)

    Liotta, Lance A; Luchini, Alessandra; Petricoin, Emanuel F; Espina, Virginia

    2015-04-21

    An immunoassay device incorporating porous polymeric capture nanoparticles within either the sample collection vessel or pre-impregnated into a porous substratum within fluid flow path of the analytical device is presented. This incorporation of capture particles within the immunoassay device improves sensitivity while removing the requirement for pre-processing of samples prior to loading the immunoassay device. A preferred embodiment is coreshell bait containing capture nanoparticles which perform three functions in one step, in solution: a) molecular size sieving, b) target analyte sequestration and concentration, and c) protection from degradation. The polymeric matrix of the capture particles may be made of co-polymeric materials having a structural monomer and an affinity monomer, the affinity monomer having properties that attract the analyte to the capture particle. This device is useful for point of care diagnostic assays for biomedical applications and as field deployable assays for environmental, pathogen and chemical or biological threat identification.

  4. In situ synthesis of silver benzene-dithiolate hybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Brenier, Roger, E-mail: roger.brenier@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Piednoir, Agnès, E-mail: agnes.piednoir@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Bertorelle, Franck, E-mail: franck.bertorelle@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Penuelas, José, E-mail: jose.penuelas@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France); Grenet, Geneviève, E-mail: genevieve.grenet@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France)

    2016-02-01

    In this article, a method for in situ synthesis of silver benzene-dithiolate hybrid films is presented. Silver nanoparticles, generated on ZrO{sub 2} films, are transformed into silver benzene 1,4-dithiolate or, partially, into silver benzene 1,2-dithiolate after sample immersion in the corresponding thiol solutions. These transformations occur at room temperature owing to the catalytic action of ZrO{sub 2}. It is also shown that TiO{sub 2} in place of ZrO{sub 2} is very efficient, both for the catalytic generation of silver nanoparticles and for their further transformation in benzene 1,4-dithiolate compound. This latter semiconductor has an optical bandgap of about 3 eV and the film is made of touching nanoparticles in an amorphous state. Our work has potential applications in the electronic and photovoltaic fields. - Highlights: • A method for in situ synthesis of silver benzene-dithiolate hybrid semiconductor films is presented. • Silver nanoparticles are, first, generated on ZrO{sub 2} or on TiO{sub 2} coated silica substrates. • The samples are immersed in benzene dithiol solution for two days at room temperature. • During the immersion, the silver nanoparticles are transformed into silver benzene dithiolate. • The silver benzene dithiolate film is made of amorphous nanoparticles with a banbgap of 3 eV.

  5. Periodontal diagnostics.

    Science.gov (United States)

    Kinane, D F

    2000-10-01

    Periodontitis affects a subset of the population and our current thinking is that progression of periodontal disease may be either continuous or cyclical (burst hypothesis). These features make screening and diagnostic tools desirable in the management of this disease. Although many potential markers exist, several difficulties hamper our ability to declare them diagnostic tests with proven utility. The 'gold standard' for active periodontal disease is not available and inflammation due to gingivally confined lesions (gingivitis) and periodontal inflammation which results in attachment loss is a potential confounder of any test based on assessing the host response elements of the disease. The current absence of proof for the progression of periodontal disease i.e., whether or not the burst hypothesis is correct, is a further problem. Although much is written about the need for markers of current or future disease which will prevent us from overtreating pockets, the time, effort and cost involved in testing these sites has to be balanced against the relative ease and speed of routine therapy such as root planing. In addition, we are still some way from the development and validation of reliable host or microbial testing methods. In terms of screening tests for diseases such as the early-onset forms of periodontitis, the research and development on diagnostic tools involving genetic polymorphisms, specific genes, systemic antibodies or leucocyte cell surface markers of the patients, may become a clinical reality in time. One could envisage chairside tests using blood from thumb pricks being capable of determining a young individual's risk of developing disease at a later age, and thus the need for a timely prevention programme. Before applying any test we should reconsider what treatment planning effects a positive or negative result will have, and any test which does not influence the treatment plan is redundant. Whether periodontal diagnostic tests will be

  6. Incorporation of copper nanoparticles into paper for point-of-use water purification

    OpenAIRE

    Dankovich, Theresa A.; Smith, James A.

    2014-01-01

    As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10 minutes and were well distributed on the paper fiber surfaces. Paper sheets were characterized by ...

  7. Silver Nanoparticles

    Science.gov (United States)

    Khaydarov, R. R.; Khaydarov, R. A.; Estrin, Y.; Evgrafova, S.; Scheper, T.; Endres, C.; Cho, S. Y.

    The bactericidal effect of silver nanoparticles obtained by a novel electrochemical method on Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium phoeniceum cultures has been studied. The tests conducted have demonstrated that synthesized silver nanoparticles — when added to water paints or cotton fabrics — show a pronounced antibacterial/antifungal effect. It was shown that smaller silver nanoparticles have a greater antibacterial/antifungal efficacy. The paper also provides a review of scientific literature with regard to recent developments in the field of toxicity of silver nanoparticles and its effect on environment and human health.

  8. Instrumentation and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Nakaishi, C.V.; Bedick, R.C.

    1990-12-01

    This Technology Status Report describes research and accomplishments for the Instrumentation and Diagnostics (I D) Projects within the Advanced Research and Technology Development (AR TD) Program of the United States Department of Energy (DOE) Office of Fossil Energy (FE). Process understanding and control can be improved through the development of advanced instrumentation and diagnostics. The thrust of the I D Projects is to further develop existing measurement and control techniques for application to advanced coal-based technologies. Project highlights are: an inductively coupled plasma (ICP) instrument has been developed to analyze trace elements in gasification and combustion process streams. An in situ two-color Mie scattering technique with LSS can simultaneously measure the size, velocity, and elemental composition of coal particles during combustion. A high-temperature, fluorescence thermometry technique has accurately measured gas temperatures during field testing in combustion and gasification environments. Expert systems have been developed to improve the control of advanced coal-based processes. Capacitance flowmeters were developed to determine the mass flowrate, solid volume fraction, and particle velocities of coal slurries. 32 refs., 9 figs.

  9. In situ observation of Cu-Ni alloy nanoparticle formation by X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy: Influence of Cu/Ni ratio

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Duchstein, Linus Daniel Leonhard; Chiarello, Gian Luca

    2014-01-01

    the same reduction conditions, the particle sizes of reduced Cu-Ni alloys decrease with increasing Ni content. Estimates of the metal surface area from sulfur chemisorption and from the XRD particle size generally agree well on the trend across the composition range, but show some disparity in terms...... of the absolute magnitude of the metal area. This work provides practical synthesis guidelines towards preparation of Cu-Ni alloy nanomaterials with different Cu/Ni ratios, and insight into the application of different in situ techniques for characterization of the alloy formation. Copyright © 2014 WILEY...

  10. Electrochemical synthesis and optical properties of organically capped silver nanoparticles

    International Nuclear Information System (INIS)

    Rabinal, M.K.; Kalasad, M.N.; Praveenkumar, K.; Bharadi, V.R.; Bhikshavartimath, A.M.

    2013-01-01

    Graphical abstract: A simple electrochemical method for the synthesis of organically capped silver nanoparticles by anodic dissolution of silver. Highlights: ► Electrochemical method has been developed to synthesize silver nanoparticles. ► The bulk silver is converted to monodispersed silver nanoparticles by anodic dissolution of metal. ► It permits in-situ capping of nanoparticles with suitable organic molecules. ► The method is simple, economical and greener in approach to prepare bulk quantity of stable sols of silver nanoparticles. -- Abstract: A top to bottom approach has been adopted to prepare silver nanoparticles by electrochemical dissolution of metal in suitable organic solvents. The method is being simple and economical, also permits in situ capping of nanoparticles with organic molecules. Thioglycolic acid is used as capping/stabilizing agent. Optical absorption, transmission electron microscopy, fourier transform infrared spectroscopy and X-ray diffraction measurements were carried out to study the effect of capping molecules on the size and shape of nanoparticles. It is found that thioglycolic acid is an effective capping agent and hence the resultant sol, even with high density of nanoparticles, is kinetically more stable. The present method can also be extended to synthesize other metal nanoparticles capped with various organic molecules

  11. Thermometry of Silicon Nanoparticles

    Science.gov (United States)

    Mecklenburg, Matthew; Zutter, Brian; Regan, B. C.

    2018-01-01

    Current thermometry techniques lack the spatial resolution required to see the temperature gradients in typical, highly scaled modern transistors. As a step toward addressing this problem, we measure the temperature dependence of the volume plasmon energy in silicon nanoparticles from room temperature to 1250 °C , using a chip-style heating sample holder in a scanning transmission electron microscope (STEM) equipped with electron energy loss spectroscopy (EELS). The plasmon energy changes as expected for an electron gas subject to the thermal expansion of silicon. Reversing this reasoning, we find that measurements of the plasmon energy provide an independent measure of the nanoparticle temperature consistent with that of the heater chip's macroscopic, dual-function heater-and-thermometer to within the 5% accuracy of the thermometer's calibration. Thus, silicon has the potential to provide its own high-spatial-resolution thermometric readout signal via measurements of its volume plasmon energy. Furthermore, nanoparticles can, in general, serve as convenient nanothermometers for in situ electron-microscopy experiments.

  12. Enhanced photothermal effect of plasmonic nanoparticles coated with reduced graphene oxide.

    Science.gov (United States)

    Lim, Dong-Kwon; Barhoumi, Aoune; Wylie, Ryan G; Reznor, Gally; Langer, Robert S; Kohane, Daniel S

    2013-09-11

    We report plasmonic gold nanoshells and nanorods coated with reduced graphene oxide that produce an enhanced photothermal effect when stimulated by near-infrared (NIR) light. Electrostatic interactions between nanosized graphene oxide and gold nanoparticles followed by in situ chemical reduction generated reduced graphene oxide-coated nanoparticles; the coating was demonstrated using Raman and HR-TEM. Reduced graphene oxide-coated gold nanoparticles showed enhanced photothermal effect compared to noncoated or nonreduced graphene oxide-coated gold nanoparticles. Reduced graphene oxide-coated gold nanoparticles killed cells more rapidly than did noncoated or nonreduced graphene oxide-coated gold nanoparticles.

  13. Biocomposites of nanofibrillated cellulose, polypyrrole, and silver nanoparticles with electroconductive and antimicrobial properties.

    Science.gov (United States)

    Bober, Patrycja; Liu, Jun; Mikkonen, Kirsi S; Ihalainen, Petri; Pesonen, Markus; Plumed-Ferrer, Carme; von Wright, Atte; Lindfors, Tom; Xu, Chunlin; Latonen, Rose-Marie

    2014-10-13

    In this work, flexible and free-standing composite films of nanofibrillated cellulose/polypyrrole (NFC/PPy) and NFC/PPy-silver nanoparticles (NFC/PPy-Ag) have been synthesized for the first time via in situ one-step chemical polymerization and applied in potential biomedical applications. Incorporation of NFC into PPy significantly improved its film formation ability resulting in composite materials with good mechanical and electrical properties. It is shown that the NFC/PPy-Ag composite films have strong inhibition effect against the growth of Gram-positive bacteria, e.g., Staphylococcus aureus. The electrical conductivity and strong antimicrobial activity makes it possible to use the silver composites in various applications aimed at biomedical treatments and diagnostics. Additionally, we report here the structural and morphological characterization of the composite materials with Fourier-transform infrared spectroscopy, atomic force microscopy, and scanning and transmission electron microscopy techniques.

  14. (BDMCA) Nanoparticles

    African Journals Online (AJOL)

    Methods: Nanoparticle formulations were fabricated by a double emulsion solvent evaporation technique using polycaprolactone as the polymer. The nanoparticles were characterised for drug content, particles size, in vitro drug release and the drug-polymer interaction. The in vivo properties of the formulations in male ...

  15. Ambient diagnostics

    CERN Document Server

    Cai, Yang

    2014-01-01

    Part I. FundamentalsIntroductionWhat is Ambient Diagnostics?Diagnostic ModelsMultimedia IntelligenceCrowd SourcingSoft SensorsScience of SimplicityPersonal DiagnosesBasic AlgorithmsBasic ToolsSummaryProblemsTransformationEarly Discoveries of Heartbeat PatternsTransforms, Features, and AttributesSequential FeaturesSpatiotemporal FeaturesShape FeaturesImagery FeaturesFrequency Domain FeaturesMulti-Resolution FeaturesSummaryProblemsPattern RecognitionSimilarities and DistancesClustering MethodsClassification MethodsClassifier Accuracy MeasuresSummaryProblemsPart II. Multimedia IntelligenceSound RecognitionMicrophone AppsModern Acoustic Transducers (Microphones)Frequency Response CharacteristicsDigital Audio File FormatsHeart Sound SensingLung Sound SensingSnore MeterSpectrogram (STFT)Ambient Sound AnalysisSound RecognitionRecognizing Asthma SoundPeak ShiftFeature CompressionRegroupingNoise IssuesFuture ApplicationsSummaryProblemsColor SensorsColor SensingHuman Color VisionColor SensorsColor Matching ExperimentsC...

  16. Intermetallic nanoparticles

    Science.gov (United States)

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  17. In-Situ Wire Damage Detection System

    Science.gov (United States)

    Williams, Martha K. (Inventor); Roberson, Luke B. (Inventor); Tate, Lanetra C. (Inventor); Smith, Trent M. (Inventor); Gibson, Tracy L. (Inventor); Jolley, Scott T. (Inventor); Medelius, Pedro J. (Inventor)

    2014-01-01

    An in-situ system for detecting damage in an electrically conductive wire. The system includes a substrate at least partially covered by a layer of electrically conductive material forming a continuous or non-continuous electrically conductive layer connected to an electrical signal generator adapted to delivering electrical signals to the electrically conductive layer. Data is received and processed to identify damage to the substrate or electrically conductive layer. The electrically conductive material may include metalized carbon fibers, a thin metal coating, a conductive polymer, carbon nanotubes, metal nanoparticles or a combination thereof.

  18. Aluminum matrix composites reinforced with alumina nanoparticles

    CERN Document Server

    Casati, Riccardo

    2016-01-01

    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  19. In situ identification of the adsorption of 4,4'-thiobisbenzenethiol on silver nanoparticles surface: a combined investigation of surface-enhanced Raman scattering and density functional theory study.

    Science.gov (United States)

    You, Ting-ting; Yin, Peng-gang; Jiang, Li; Lang, Xiu-feng; Guo, Lin; Yang, Shi-he

    2012-05-21

    We investigated the configuration characteristic and adsorption behavior of 4,4'-thiobisbenzenethiol (TBBT) on the surface of silver nanoparticles (NPs). Under different conditions and preparation processes, several possible surface species were produced including single-end adsorption on a silicon wafer, double-end adsorption and bridge-like adsorption. Although consisting of the same molecule and nano material, different adsorption systems exhibited different spectral characteristics in the surface-enhanced Raman spectroscopy (SERS). A density functional theory (DFT) study further verified the corresponding adsorption states. The combined SERS-DFT study provided a framework towards investigating and designing adsorption systems at a molecular level, indicating the potential use in applications such as nano-sensors.

  20. Zwitterionic supramolecular nanoparticles: self-assembly and responsive properties

    NARCIS (Netherlands)

    Stoffelen, C.; Huskens, Jurriaan

    2015-01-01

    Supramolecular nanoparticles (SNPs) are of high interest in both nanoscience and molecular diagnostics and therapeutics, because of their reversible and designable properties. To ensure colloidal stabilization and biocompatibility, most reported strategies require the use of hydrophilic long-chain

  1. Diagnostic accuracy of organ electrodermal diagnostics | Szopinski ...

    African Journals Online (AJOL)

    Objective. To estimate the diagnostic accuracy as well as the scope of utilisation of a new bio-electronic method of organ diagnostics. Design. Double-blind comparative study of the diagnostic results obtained by means of organ electrodermal diagnostics (OED) and clinical diagnoses, as a criterion standard. Setting.

  2. Enrichment of colloidal solutions by nanoparticles in underwater spark discharge

    International Nuclear Information System (INIS)

    Lopat'ko, K.; Aftandiliants, Y.; Veklich, A.; Boretskij, V.; Taran, N.; Batsmanova, L.; Trach, V.; Tugai, T.

    2015-01-01

    The underwater spark discharge between manganese granules was studied. Optical emission spectroscopy methods were used for diagnostics of such discharge plasma. The colloidal solution with manganese nanoparticles was produced by this discharge. The biological applications of this colloid were analyzed. The mechanism of metallic nanoparticle action and their transformation at interacting with biological objects were studied in Alternaria alternata culture

  3. Inorganic Nanoparticles for Multimodal Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Magdalena Swierczewska

    2011-01-01

    Full Text Available Multimodal molecular imaging can offer a synergistic improvement of diagnostic ability over a single imaging modality. Recent development of hybrid imaging systems has profoundly impacted the pool of available multimodal imaging probes. In particular, much interest has been focused on biocompatible, inorganic nanoparticle-based multimodal probes. Inorganic nanoparticles offer exceptional advantages to the field of multimodal imaging owing to their unique characteristics, such as nanometer dimensions, tunable imaging properties, and multifunctionality. Nanoparticles mainly based on iron oxide, quantum dots, gold, and silica have been applied to various imaging modalities to characterize and image specific biologic processes on a molecular level. A combination of nanoparticles and other materials such as biomolecules, polymers, and radiometals continue to increase functionality for in vivo multimodal imaging and therapeutic agents. In this review, we discuss the unique concepts, characteristics, and applications of the various multimodal imaging probes based on inorganic nanoparticles.

  4. Metal Nanoparticles in Ionic Liquids.

    Science.gov (United States)

    Wegner, Susann; Janiak, Christoph

    2017-08-01

    During the last years ionic liquids (ILs) were increasingly used and investigated as reaction media, hydrogen sources, catalysts, templating agents and stabilizers for the synthesis of (monometallic and bimetallic) metal nanoparticles (M-NPs). Especially ILs with 1,3-dialkyl-imidazolium cations featured prominently in the formation and stabilization of M-NPs. This chapter summarizes studies which focused on the interdependencies of the IL with the metal nanoparticle and tried to elucidate, for example, influences of the IL-cation, -anion and alkyl chain length. Qualitatively, the size of M-NPs was found to increase with the size of the IL-anion. The influence of the size of imidazolium-cation is less clear. The M-NP size was both found to increase and to decrease with increasing chain lengths of the 1,3-dialkyl-imidazolium cation. It is evident from such reports on cation and anion effects of ILs that the interaction between an IL and a (growing) metal nanoparticle is far from understood. Factors like IL-viscosity, hydrogen-bonding capability and the relative ratio of polar and non-polar domains of ILs may also influence the stability of nanoparticles in ionic liquids and an improved understanding of the IL-nanoparticle interaction would be needed for a more rational design of nanomaterials in ILs. Furthermore, thiol-, ether-, carboxylic acid-, amino- and hydroxyl-functionalized ILs add to the complexity by acting also as coordinating capping ligands. In addition imidazolium cations are precursors to N-heterocyclic carbenes, NHCs which form from imidazolium-based ionic liquids by in situ deprotonation at the acidic C2-H ring position as intermediate species during the nanoparticle seeding and growth process or as surface coordinating ligand for the stabilization of the metal nanoparticle.

  5. In situ measurement of conductivity during nanocomposite film deposition

    International Nuclear Information System (INIS)

    Blattmann, Christoph O.; Pratsinis, Sotiris E.

    2016-01-01

    Highlights: • Flame-made nanosilver dynamics are elucidated in the gas-phase & on substrates. • The resistance of freshly depositing nanosilver layers is monitored. • Low T g polymers facilitate rapid synthesis of conductive films. • Conductive nanosilver films form on top of or within the polymer depending on MW. - Abstract: Flexible and electrically conductive nanocomposite films are essential for small, portable and even implantable electronic devices. Typically, such film synthesis and conductivity measurement are carried out sequentially. As a result, optimization of filler loading and size/morphology characteristics with respect to film conductivity is rather tedious and costly. Here, freshly-made Ag nanoparticles (nanosilver) are made by scalable flame aerosol technology and directly deposited onto polymeric (polystyrene and poly(methyl methacrylate)) films during which the resistance of the resulting nanocomposite is measured in situ. The formation and gas-phase growth of such flame-made nanosilver, just before incorporation onto the polymer film, is measured by thermophoretic sampling and microscopy. Monitoring the nanocomposite resistance in situ reveals the onset of conductive network formation by the deposited nanosilver growth and sinternecking. The in situ measurement is much faster and more accurate than conventional ex situ four-point resistance measurements since an electrically percolating network is detected upon its formation by the in situ technique. Nevertheless, general resistance trends with respect to filler loading and host polymer composition are consistent for both in situ and ex situ measurements. The time lag for the onset of a conductive network (i.e., percolation) depends linearly on the glass transition temperature (T g ) of the host polymer. This is attributed to the increased nanoparticle-polymer interaction with decreasing T g . Proper selection of the host polymer in combination with in situ resistance monitoring

  6. In situ measurement of conductivity during nanocomposite film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Blattmann, Christoph O.; Pratsinis, Sotiris E., E-mail: sotiris.pratsinis@ptl.mavt.ethz.ch

    2016-05-15

    Highlights: • Flame-made nanosilver dynamics are elucidated in the gas-phase & on substrates. • The resistance of freshly depositing nanosilver layers is monitored. • Low T{sub g} polymers facilitate rapid synthesis of conductive films. • Conductive nanosilver films form on top of or within the polymer depending on MW. - Abstract: Flexible and electrically conductive nanocomposite films are essential for small, portable and even implantable electronic devices. Typically, such film synthesis and conductivity measurement are carried out sequentially. As a result, optimization of filler loading and size/morphology characteristics with respect to film conductivity is rather tedious and costly. Here, freshly-made Ag nanoparticles (nanosilver) are made by scalable flame aerosol technology and directly deposited onto polymeric (polystyrene and poly(methyl methacrylate)) films during which the resistance of the resulting nanocomposite is measured in situ. The formation and gas-phase growth of such flame-made nanosilver, just before incorporation onto the polymer film, is measured by thermophoretic sampling and microscopy. Monitoring the nanocomposite resistance in situ reveals the onset of conductive network formation by the deposited nanosilver growth and sinternecking. The in situ measurement is much faster and more accurate than conventional ex situ four-point resistance measurements since an electrically percolating network is detected upon its formation by the in situ technique. Nevertheless, general resistance trends with respect to filler loading and host polymer composition are consistent for both in situ and ex situ measurements. The time lag for the onset of a conductive network (i.e., percolation) depends linearly on the glass transition temperature (T{sub g}) of the host polymer. This is attributed to the increased nanoparticle-polymer interaction with decreasing T{sub g}. Proper selection of the host polymer in combination with in situ resistance

  7. Dietary iron-loaded rat liver haemosiderin and ferritin: in situ measurement of iron core nanoparticle size and cluster structure using anomalous small-angle x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bovell, Eliza; Buckley, Craig E.; Chua-anusorn, Wanida; Cookson, David; Kirby, Nigel; Saunders, Martin; St. Pierre, Timothy G. ((UWA)); ((Curtin U.)); ((ASRP))

    2009-03-16

    The morphology, particle size distribution and cluster structure of the hydrated iron(III) oxyhydroxide particles associated with haemosiderin and ferritin in dietary iron-loaded rat liver tissue have been investigated using transmission electron microscopy (TEM) and anomalous small-angle x-ray scattering (ASAXS). Rat liver tissue was removed from a series of female Porton rats which had been fed an iron-rich diet until sacrifice at various ages from 2-24 months. Hepatic iron concentrations ranged from 1 to 65 mg Fe g{sup -1} dry tissue. TEM studies showed both dispersed and clustered iron-containing nanoparticles. The dispersed particles were found to have mean sizes ({+-}standard deviation) of 54 {+-} 8 {angstrom} for the iron-loaded animals and 55 {+-} 7 {angstrom} for the controls. Superposition of particles in TEM images prevented direct measurement of nanoparticulate size in the clusters. The ASAXS data were modelled to provide a quantitative estimate of both the size and spacing of iron oxyhydroxide particles in the bulk samples. The modelling yielded close-packed particles with sizes of 60 to 78 {angstrom} which when corrected for anomalous scattering suggests sizes from 54 to 70 {angstrom}. Particle size distributions are of particular importance since they determine the surface iron to core iron ratios, which in turn are expected to be related to the molar toxicity of iron deposits in cells.

  8. Monitoring the environmental effects of CeO2 and ZnO nanoparticles through the life cycle of corn (Zea mays) plants and in situ μ-XRF mapping of nutrients in kernels.

    Science.gov (United States)

    Zhao, Lijuan; Sun, Youping; Hernandez-Viezcas, Jose A; Hong, Jie; Majumdar, Sanghamitra; Niu, Genhua; Duarte-Gardea, Maria; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2015-03-03

    Information about changes in physiological and agronomic parameters through the life cycle of plants exposed to engineered nanoparticles (NPs) is scarce. In this study, corn (Zea mays) plants were cultivated to full maturity in soil amended with either nCeO2 or nZnO at 0, 400, and 800 mg/kg. Gas exchange was monitored every 10 days, and at harvest, bioaccumulation of Ce and Zn in tissues was determined by ICP-OES/MS. The effects of NPs exposure on nutrient concentration and distribution in ears were also evaluated by ICP-OES and μ-XRF. Results showed that nCeO2 at both concentrations did not impact gas exchange in leaves at any growth stage, while nZnO at 800 mg/kg reduced net photosynthesis by 12%, stomatal conductance by 15%, and relative chlorophyll content by 10% at day 20. Yield was reduced by 38% with nCeO2 and by 49% with nZnO. Importantly, μ-XRF mapping showed that nCeO2 changed the allocation of calcium in kernels, compared to controls. In nCeO2 treated plants, Cu, K, Mn, and Zn were mainly localized at the insertion of kernels into cobs, but Ca and Fe were distributed in other parts of the kernels. Results showed that nCeO2 and nZnO reduced corn yield and altered quality of corn.

  9. Mitigation diagnostics

    International Nuclear Information System (INIS)

    Hall, S.T.

    1990-01-01

    This paper reports that experience in the remediation of schools and other large buildings has shown the importance of the effects of both the location of geologic sources and HVAC-induced distribution of indoor radon. In general, elevated radon in areas of schools with evenly distributed HVAC pressures are correlated with maximum soil radon emanations. However, strong or unequal HVAC effects can redistribute indoor radon to areas away from the direct source. Effective remediation required a complete understanding of both contributions. In some schools, highest indoor radon levels were located near large return ducts and were attributed to proximity to negative HVAC pressure. Successful sub-slab depressurization systems were installed, however, in rooms with lower indoor but greatest sub-slab radon levels, closest to the source. This shows the inadequacy of using indoor radon levels alone as a basis for remediation. Wings of two other schools with radon problems have equivalent window fan coil units in rooms of equal size and no central HVAC system. Highest indoor radon levels correlated well with highest sub-slab radon levels due to the equivalent effects of the window units. Diagnostic tests in other schools have revealed: blockwall radon transport to upper floors; high blockwall radon adjacent to sub-slab sources; and elevated indoor radon over crawlspace being drawn upward by HVAC-induced negative pressure, determined from indoor to outdoor micromanometer measurements

  10. Calibration issues for neutron diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Sadler, G.J. [JET Joint Undertaking, Abingdon (United Kingdom); Adams, J.M. [AEA Technology, Harwell (United Kingdom); Barnes, C.W. [Los Alamos National Lab., NM (United States)] [and others

    1997-12-01

    The performance of diagnostic systems are limited by their weakest constituents, including their calibration issues. Neutron diagnostics are notorious for problems encountered while determining their absolute calibrations, due mainly to the nature of the neutron transport problem. In order to facilitate the determination of an accurate and precise calibration, the diagnostic design should be such as to minimize the scattered neutron flux. ITER will use a comprehensive set of neutron diagnostics--comprising radial and vertical neutron cameras, neutron spectrometers, a neutron activation system and internal and external fission chambers--to provide accurate measurements of fusion power and power densities as a function of time. The calibration of such an important diagnostic system merits careful consideration. Some thoughts have already been given to this subject during the conceptual design phase in relation to the time-integrated neutron activation and time-dependent neutron yield monitors. However, no overall calibration strategy has been worked out so far. This paper represents a first attempt to address this vital issue. Experience gained from present large tokamaks (JET, TFTR and JT60U) and proposals for ITER are reviewed. The need to use a 14-MeV neutron generator as opposed to radioactive sources for in-situ calibration of D-T diagnostics will be stressed. It is clear that the overall absolute determination of fusion power will have to rely on a combination of nuclear measuring techniques, for which the provision of accurate and independent calibrations will constitute an ongoing process as ITER moves from one phase of operation to the next.

  11. An amplified electrochemical immunosensor based on in situ-produced 1-naphthol as electroactive substance and graphene oxide and Pt nanoparticles functionalized CeO2 nanocomposites as signal enhancer.

    Science.gov (United States)

    Yang, Zhe-Han; Zhuo, Ying; Yuan, Ruo; Chai, Ya-Qin

    2015-07-15

    In this work, an amplified electrochemical immunosensor based on 1-naphthol as electroactive substance and Pt/CeO2/GO composites as catalytic amplifier was constructed for sensitive detection influenza. Through "sandwich" reaction, the Pt/CeO2/GO functionalized bioconjugates were captured on electrode surface and the electrochemical signal directly originated from 1-naphthol, which was in situ produced with high local concentration though the hydrolysis of 1-naphthyl phosphate catalyzed by ALP. Then, 1-naphthol as new reactant was oxidized by Pt/CeO2/GO composites with outstanding catalytic performance, resulting in detection signal amplification. In addition, as compared to label electroactive substance to antibodies, a simplified preparative step of immunosensor could be achieved because the signal probe get rid of introducation other electroactive substances. The proposed immunosensor achieved a linear range of 1.0×10(-3)-1.0ngmL(-1) and 5.0 to 1.0×10(2)ngmL(-1) with a detection limit of 0.43pgmL(-1) (defined as S/N=3). Copyright © 2015. Published by Elsevier B.V.

  12. Loading technique for preparing radionuclide containing nanoparticles

    DEFF Research Database (Denmark)

    2011-01-01

    Source: US2012213698A The present invention relates to a novel composition and method for loading delivery systems such as liposome compositions with radionuclides useful in targeted diagnostic and/or therapy of target site, such as cancerous tissue and, in general, pathological conditions associ...... of positron emission tomography (PET) imaging technique. One specific aspect of the invention is directed to a method of producing nanoparticles with desired targeting properties for diagnostic and/or radio-therapeutic applications....

  13. Controllable In-Situ Synthesis of Magnetite Coated Silica-Core Water-Dispersible Hybrid Nanomaterials

    Science.gov (United States)

    Qu, Haiou; Tong, Sheng; Song, Kejing; Ma, Hui; Bao, Gang; Pincus, Seth; Zhou, Weilie; O'Connor, Charles

    2013-01-01

    Magnetite nanoparticle coated silica (Fe3O4@SiO2) hybrid nanomaterials hold an important position in the fields of cell imaging and drug delivery. Here we report a large scale synthetic procedure that allows attachment of magnetite nanoparticles onto a silica surface in-situ. Many different silica nanomaterials such as Stöber silica nanospheres, mesoporous silica nanoparticles, and hollow silica nanotube have been coated with a high density layer of water-dispersible magnetite nanoparticles. The size and attachment efficiency of the magnetite nanoparticle can be well tuned by adjusting the precursor concentration and reflux time. The functionalization of Fe3O4@SiO2 nanoparticles with dye molecules and biocompatible polymers impart optical imaging modality and good colloidal stability in either buffer solution or serum. The functionalized materials also exhibited strong potential as negative contrast agents in T2 weighted magnetic resonance imaging. PMID:23889037

  14. Controllable in situ synthesis of magnetite coated silica-core water-dispersible hybrid nanomaterials.

    Science.gov (United States)

    Qu, Haiou; Tong, Sheng; Song, Kejing; Ma, Hui; Bao, Gang; Pincus, Seth; Zhou, Weilie; O'Connor, Charles

    2013-08-20

    Magnetite nanoparticle coated silica (Fe3O4@SiO2) hybrid nanomaterials hold an important position in the fields of cell imaging and drug delivery. Here we report a large scale synthetic procedure that allows attachment of magnetite nanoparticles onto a silica surface in situ. Many different silica nanomaterials such as Stöber silica nanospheres, mesoporous silica nanoparticles, and hollow silica nanotubes have been coated with a high density layer of water-dispersible magnetite nanoparticles. The size and attachment efficiency of the magnetite nanoparticle can be well tuned by adjusting the precursor concentration and reflux time. The functionalization of Fe3O4@SiO2 nanoparticles with dye molecules and biocompatible polymers impart optical imaging modality and good colloidal stability in either buffer solution or serum. The functionalized materials also exhibited strong potential as negative contrast agents in T2 weighted magnetic resonance imaging.

  15. High Density Data Storage Systems by DNA Complexes and Nano-Particles from DNA Hybrid Materials

    National Research Council Canada - National Science Library

    Ogata, Naoya

    2006-01-01

    ...) In-situ Intercalation of Phtharocyanine dye (PC) into DNA and Polyamine Complex, (3) syntheses and characterization of Nano-particles derived from DNA-polymer Hybrid Materials Containing Optical Dyes, and (4...

  16. Transport of Fluorescently Labeled Hydroxyapatite Nanoparticles in Saturated Granular Media at Environmentally Relevant Concentrations of Surfactants

    Science.gov (United States)

    Little is known about the mobility of engineered nanoparticles (ENPs) in granular media at environmentally relevant concentration of surfactant, which represents a critical knowledge gap in employing ENPs for in-situ remediation of contaminated groundwater. In this study, transpo...

  17. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    Science.gov (United States)

    Venkatasubbarao, Srivatsa

    2008-01-01

    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  18. Reactor for nano-focused x-ray diffraction and imaging under catalytic in situ conditions

    Science.gov (United States)

    Richard, M.-I.; Fernández, S.; Hofmann, J. P.; Gao, L.; Chahine, G. A.; Leake, S. J.; Djazouli, H.; De Bortoli, Y.; Petit, L.; Boesecke, P.; Labat, S.; Hensen, E. J. M.; Thomas, O.; Schülli, T.

    2017-09-01

    A reactor cell for in situ studies of individual catalyst nanoparticles or surfaces by nano-focused (coherent) x-ray diffraction has been developed. Catalytic reactions can be studied in flow mode in a pressure range of 10-2-103 mbar and temperatures up to 900 °C. This instrument bridges the pressure and materials gap at the same time within one experimental setup. It allows us to probe in situ the structure (e.g., shape, size, strain, faceting, composition, and defects) of individual nanoparticles using a nano-focused x-ray beam. Here, the setup was used to observe strain and facet evolution of individual model Pt catalysts during in situ experiments. It can be used for heating other (non-catalytically active) nanoparticles (e.g., nanowires) in inert or reactive gas atmospheres or vacuum as well.

  19. Lipid nanoparticle interactions and assemblies

    Science.gov (United States)

    Preiss, Matthew Ryan

    Novel liposome-nanoparticle assemblies (LNAs) provide a biologically inspired route for designing multifunctional bionanotheranostics. LNAs combine the benefits of lipids and liposomes to encapsulate, transport, and protect hydrophilic and hydrophobic therapeutics with functional nanoparticles. Functional nanoparticles endow LNAs with additional capabilities, including the ability to target diseases, triggered drug release, controlled therapeutic output, and diagnostic capabilities to produce a drug delivery system that can effectively and efficiently deliver therapeutics while reducing side effects. Not only could LNAs make existing drugs better, they could also provide an avenue to allow once promising non-approved drugs (rejected due to harmful side effects, inadequate pharmacokinetics, and poor efficacy) to be safely used through targeted and controlled delivery directly to the diseased site. LNAs have the potential to be stimuli responsive, delivering drugs on command by external (ultrasound, RF heating, etc.) or internal (pH, blood sugar, heart rate, etc.) stimuli. Individually, lipids and nanoparticles have been clinically approved for therapy, such as Doxil (a liposomal doxorubicin for cancer treatment), and diagnosis, such as Feridex (an iron oxide nanoparticle an MRI contrast enhancement agent for liver tumors). In order to engineer these multifunctional LNAs for theranostic applications, the interactions between nanoparticles and lipids must be better understood. This research sought to explore the formation, design, structures, characteristics, and functions of LNAs. To achieve this goal, different types of LNAs were formed, specifically magnetoliposomes, bilayer decorated LNAs (DLNAs), and lipid-coated magnetic nanoparticles (LMNPs). A fluorescent probe was embedded in the lipid bilayer of magnetoliposomes allowing the local temperature and membrane fluidity to be observed. When subjected to an electromagnetic field that heated the encapsulated iron

  20. Tunable nanoparticle arrays at charged interfaces.

    Science.gov (United States)

    Srivastava, Sunita; Nykypanchuk, Dmytro; Fukuto, Masafumi; Gang, Oleg

    2014-10-28

    Structurally tunable two-dimensional (2D) arrays of nanoscale objects are important for modulating functional responses of thin films. We demonstrate that such tunable and ordered nanoparticles (NP) arrays can be assembled at charged air-water interfaces from nanoparticles coated with polyelectrolyte chains, DNA. The electrostatic attraction between the negatively charged nonhybridizing DNA-coated gold NPs and a positively charged lipid layer at the interface facilitates the formation of a 2D hexagonally closed packed (HCP) nanoparticle lattice. We observed about 4-fold change of the monolayer nanoparticle density by varying the ionic strength of the subphase. The tunable NP arrays retain their structure reasonably well when transferred to a solid support. The influence of particle's DNA corona and lipid layer composition on the salt-induced in-plane and normal structural evolution of NP arrays was studied in detail using a combination of synchrotron-based in situ surface scattering methods, grazing incidence X-ray scattering (GISAXS), and X-ray reflectivity (XRR). Comparative analysis of the interparticle distances as a function of ionic strength reveals the difference between the studied 2D nanoparticle arrays and analogous bulk polyelectrolyte star polymers systems, typically described by Daoud-Cotton model and power law scaling. The observed behavior of the 2D nanoparticle array manifests a nonuniform deformation of the nanoparticle DNA corona due to its electrostatically induced confinement at the lipid interface. The present study provides insight on the interfacial properties of the NPs coated with charged soft shells.

  1. Quality and diagnostic perspectives in laboratory diagnostics

    OpenAIRE

    Müller, Mathias M.

    2010-01-01

    Laboratory diagnostics is a medical discipline playing an important part in patient management. In laboratory medicine meaningful, accurate and precise routine measurements are essential for diagnosis, risk assessment, treatment and follow-up of patients. The contribution of the diagnostic laboratory in the overall diagnostic process is app. 40-60%, depending on the kind of disease status investigated. The diagnostic laboratory uses nowadays more than 1.000 different tests mostly provided by ...

  2. What Is Diagnostic Testing?

    Science.gov (United States)

    ... you want to learn. Search form Search Diagnostic testing You are here Home Testing & Services Testing for ... help you make the decision. What Is Diagnostic Testing? Diagnostic genetic testing can usually work out if ...

  3. Ultrasound mediated nanoparticle drug delivery

    Science.gov (United States)

    Mullin, Lee B.

    Ultrasound is not only a powerful diagnostic tool, but also a promising therapeutic technology that can be used to improve localized drug delivery. Microbubble contrast agents are micron sized encapsulated gas filled bubbles that are administered intravenously. Originally developed to enhance ultrasound images, microbubbles are highly echogenic due to the gas core that provides a detectable impedance difference from the surrounding medium. The core also allows for controlled response of the microbubbles to ultrasound pulses. Microbubbles can be pushed using acoustic radiation force and ruptured using high pressures. Destruction of microbubbles can increase permeability at the cellular and vascular level, which can be advantageous for drug delivery. Advances in drug delivery methods have been seen with the introduction of nanoparticles, nanometer sized objects often carrying a drug payload. In chemotherapy, nanoparticles can deliver drugs to tumors while limiting systemic exposure due to abnormalities in tumor vasculature such large gaps between endothelial cells that allow nanoparticles to enter into the interstitial space; this is referred to as the enhanced permeability and retention (EPR) effect. However, this effect may be overestimated in many tumors. Additionally, only a small percentage of the injected dose accumulates in the tumor, which most the nanoparticles accumulating in the liver and spleen. It is hypothesized that combining the acoustic activity of an ultrasound contrast agent with the high payload and extravasation ability of a nanoparticle, localized delivery to the tumor with reduced systemic toxicity can be achieved. This method can be accomplished by either loading nanoparticles onto the shell of the microbubble or through a coadministration method of both nanoparticles and microbubbles. The work presented in this dissertation utilizes novel and commercial nanoparticle formulations, combined with microbubbles and a variety of ultrasound systems

  4. Sonochemical Synthesis of Cobalt Ferrite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Partha P. Goswami

    2013-01-01

    Full Text Available Cobalt ferrite being a hard magnetic material with high coercivity and moderate magnetization has found wide-spread applications. In this paper, we have reported the sonochemical synthesis of cobalt ferrite nanoparticles using metal acetate precursors. The ferrite synthesis occurs in three steps (hydrolysis of acetates, oxidation of hydroxides, and in situ microcalcination of metal oxides that are facilitated by physical and chemical effects of cavitation bubbles. The physical and magnetic properties of the ferrite nano-particles thus synthesized have been found to be comparable with those reported in the literature using other synthesis techniques.

  5. Quantitative Image Simulation and Analysis of Nanoparticles

    DEFF Research Database (Denmark)

    Madsen, Jacob; Hansen, Thomas Willum

    Microscopy (HRTEM) has become a routine analysis tool for structural characterization at atomic resolution, and with the recent development of in-situ TEMs, it is now possible to study catalytic nanoparticles under reaction conditions. However, the connection between an experimental image, and the underlying...... of strain measurements from TEM images, and investigate the stability of these measurements to microscope parameters. This is followed by our efforts toward simulating metal nanoparticles on a metal-oxide support using the Charge Optimized Many Body (COMB) interatomic potential. The simulated interface...

  6. Noble Metal Nanoparticles Applications in Cancer

    Directory of Open Access Journals (Sweden)

    João Conde

    2012-01-01

    Full Text Available Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings.

  7. Noble Metal Nanoparticles for Biosensing Applications

    Science.gov (United States)

    Doria, Gonçalo; Conde, João; Veigas, Bruno; Giestas, Leticia; Almeida, Carina; Assunção, Maria; Rosa, João; Baptista, Pedro V.

    2012-01-01

    In the last decade the use of nanomaterials has been having a great impact in biosensing. In particular, the unique properties of noble metal nanoparticles have allowed for the development of new biosensing platforms with enhanced capabilities in the specific detection of bioanalytes. Noble metal nanoparticles show unique physicochemical properties (such as ease of functionalization via simple chemistry and high surface-to-volume ratios) that allied with their unique spectral and optical properties have prompted the development of a plethora of biosensing platforms. Additionally, they also provide an additional or enhanced layer of application for commonly used techniques, such as fluorescence, infrared and Raman spectroscopy. Herein we review the use of noble metal nanoparticles for biosensing strategies—from synthesis and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics laboratory. PMID:22438731

  8. Nanomedicine: Drug Delivery Systems and Nanoparticle Targeting

    International Nuclear Information System (INIS)

    Youn, Hye Won; Kang, Keon Wook; Chung, Jun Key; Lee, Dong Soo

    2008-01-01

    Applications of nanotechnology in the medical field have provided the fundamentals of tremendous improvement in precise diagnosis and customized therapy. Recent advances in nanomedicine have led to establish a new concept of theragnosis, which utilizes nanomedicines as a therapeutic and diagnostic tool at the same time. The development of high affinity nanoparticles with large surface area and functional groups multiplies diagnostic and therapeutic capacities. Considering the specific conditions related to the disease of individual patient, customized therapy requires the identification of disease target at the cellular and molecular level for reducing side effects and enhancing therapeutic efficiency. Well-designed nanoparticles can minimize unnecessary exposure of cytotoxic drugs and maximize targeted localization of administrated drugs. This review will focus on major pharmaceutical nanomaterials and nanoparticles as key components of designing and surface engineering for targeted theragnostic drug development

  9. In situ synthesis of nanocomposite membranes: comprehensive improvement strategy for direct methanol fuel cells.

    Science.gov (United States)

    Rao, Siyuan; Xiu, Ruijie; Si, Jiangju; Lu, Shanfu; Yang, Meng; Xiang, Yan

    2014-03-01

    In situ synthesis is a powerful approach to control nanoparticle formation and consequently confers extraordinary properties upon composite membranes relative to conventional doping methods. Herein, uniform nanoparticles of cesium hydrogen salts of phosphotungstic acid (CsPW) are controllably synthesized in situ in Nafion to form CsPW–Nafion nanocomposite membranes with both improved proton conductivity and methanol-crossover suppression. A 101.3% increase of maximum power density has been achieved relative to pristine Nafion in a direct methanol fuel cell (DMFC), indicating a potential pathway for large-scale fabrication of DMFC alternative membranes.

  10. Nanoparticle standards

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-08

    We will purchase a COTS materials printer and adapt it for solution printing of known elemental concentration solutions. A methodology will be developed to create deposits of known mass in known locations on selected substrates. The deposits will be characterized for deposited mass, physical morphology, thickness and uniformity. Once an acceptable methodology has been developed and validated, we will create round robin samples to be characterized by LGSIMS instruments at LANL, PNNL and NIST. We will demonstrate the feasibility of depositing nanoparticles in known masses with the goal of creating separated nanoparticles in known locations.

  11. In vitro and in vivo toxicity assessment of nanoparticles

    Science.gov (United States)

    Kumar, Vinay; Sharma, Neha; Maitra, S. S.

    2017-11-01

    Nanotechnology has revolutionized gene therapy, diagnostics and environmental remediation. Their bulk production, uses and disposal have posed threat to the environment. With the appearance of these nanoparticles in the environment, their toxicity assessment is an immediate concern. This review is an attempt to summarize the major techniques used in cytotoxity determination. The review also presents a detailed and elaborative discussion on the toxicity imposed by different types of nanoparticles including carbon nanotubes, gold nanoparticles, silver nanoparticles, quantum dots, fullerenes, aluminium nanoparticles, zinc nanoparticles, iron nanoparticles, titanium nanoparticles and silica nanoparticles. It discusses the in vitro and in vivo toxological effects of nanoparticles on bacteria, microalgae, zebrafish, crustacean, fish, rat, mouse, pig, guinea pig, human cell lines and human. It also discusses toxological effects on organs such as liver, kidney, spleen, sperm, neural tissues, liver lysosomes, spleen macrophages, glioblastoma cells, hematoma cells and various mammalian cell lines. It provides information about the effects of nanoparticles on the gene-expression, growth and reproduction of the organisms.

  12. Engineering tailored nanoparticles with microbes: quo vadis?

    Science.gov (United States)

    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. © 2015 Wiley Periodicals, Inc.

  13. In situ groundwater bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, Terry C.

    2009-02-01

    In situ groundwater bioremediation of hydrocarbons has been used for more than 40 years. Most strategies involve biostimulation; however, recently bioaugmentation have been used for dehalorespiration. Aquifer and contaminant profiles are critical to determining the feasibility and strategy for in situ groundwater bioremediation. Hydraulic conductivity and redox conditions, including concentrations of terminal electron acceptors are critical to determine the feasibility and strategy for potential bioremediation applications. Conceptual models followed by characterization and subsequent numerical models are critical for efficient and cost effective bioremediation. Critical research needs in this area include better modeling and integration of remediation strategies with natural attenuation.

  14. (shell) nanoparticles

    Indian Academy of Sciences (India)

    nanoparticles the quasistatic approximation is not appropriate and Mie theory illustrates SPR due to dipole and quadrupole in extinction ... The time-dependent local density approximation (TDLDA) [19] .... satile technique for determining the optical properties of nanoshells or any other spherical particles of any dimension.

  15. From silver nanoparticles to nanostructures through matrix chemistry

    International Nuclear Information System (INIS)

    Ayyad, Omar; Munoz-Rojas, David; Oro-Sole, Judith; Gomez-Romero, Pedro

    2010-01-01

    Direct in situ reduction of silver ions by a biopolymer such as agar, without any other reducing nor capping agent is shown in this article to lead either to nanoparticles (typically 12(2) nm in an optimized case) or to more complex nanostructures depending on the reaction conditions used. This approach takes advantage of the porous polymer lattice acting as a template and leads to hybrid Ag-Agar materials with long-term synergic stability. Silver acts as an antibacterial agent for agar whereas the biopolymer prevents agglomeration of the inorganic nanoparticles leading to a stable nanocomposite formed by a thermoreversible biopolymer from which silver nanoparticles can eventually be recovered.

  16. Multifunctional Silica Nanoparticles Modified via Silylated-Decaborate Precursors

    Directory of Open Access Journals (Sweden)

    Fatima Abi-Ghaida

    2015-01-01

    Full Text Available A new class of multifunctional silica nanoparticles carrying boron clusters (10-vertex closo-decaborate and incorporating luminescent centers (fluorescein has been developed as potential probes/carriers for potential application in boron neutron capture therapy (BNCT. These silica nanoparticles were charged in situ with silylated-fluorescein fluorophores via the Stöber method and their surface was further functionalized with decaborate-triethoxysilane precursors. The resulting decaborate dye-doped silica nanoparticles were characterized by TEM, solid state NMR, DLS, nitrogen sorption, elemental analysis, and fluorescence spectroscopy.

  17. A facile route to synthesize nanogels doped with silver nanoparticles

    Science.gov (United States)

    Coll Ferrer, M. Carme; Ferrier, Robert C.; Eckmann, David M.; Composto, Russell J.

    2013-01-01

    In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core-shell polymer host containing silver nanoparticles. First, the nanogels (NG, 160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, 5 nm) are synthesized "in situ" in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

  18. Nanotechnology based diagnostics for neurological disorders

    International Nuclear Information System (INIS)

    Kurek, Nicholas S.; Chandra, Sathees B.

    2012-01-01

    Nanotechnology involves probing and manipulating matter at the molecular level. Nanotechnology based molecular diagnostics have the potential to alleviate the suffering caused by many diseases, including neurological disorders, due to the unique properties of nanomaterials. Most neurological illnesses are multifactorial conditions and many of these are also classified as neurobehavioral disorders. Alzheimer's disease, Parkinson's disease, Huntington disease, cerebral ischemia, epilepsy, schizophrenia and autism spectrum disorders like Rett syndrome are some examples of neurological disorders that could be better treated, diagnosed, prevented and possibly cured using nanotechnology. In order to improve the quality of life for disease afflicted people, a wide range of nanomaterials that include gold and silica nanoparticles, quantum dots and DNA along with countless other forms of nanotechnology have been investigated regarding their usefulness in advancing molecular diagnostics. Other small scaled materials like viruses and proteins also have potential for use as molecular diagnostic tools. Information obtained from nanotechnology based diagnostics can be stored and manipulated using bioinformatics software. More advanced nanotechnology based diagnostic procedures for the acquisition of even greater proteomic and genomic knowledge can then be developed along with better ways to fight various diseases. Nanotechnology also has numerous applications besides those related to biotechnology and medicine. In this article, we will discuss and analyze many novel nanotechnology based diagnostic techniques at our disposal today. (author)

  19. Nanotechnology based diagnostics for neurological disorders

    Energy Technology Data Exchange (ETDEWEB)

    Kurek, Nicholas S.; Chandra, Sathees B., E-mail: schandra@roosevelt.edu [Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, IL (United States)

    2012-07-01

    Nanotechnology involves probing and manipulating matter at the molecular level. Nanotechnology based molecular diagnostics have the potential to alleviate the suffering caused by many diseases, including neurological disorders, due to the unique properties of nanomaterials. Most neurological illnesses are multifactorial conditions and many of these are also classified as neurobehavioral disorders. Alzheimer's disease, Parkinson's disease, Huntington disease, cerebral ischemia, epilepsy, schizophrenia and autism spectrum disorders like Rett syndrome are some examples of neurological disorders that could be better treated, diagnosed, prevented and possibly cured using nanotechnology. In order to improve the quality of life for disease afflicted people, a wide range of nanomaterials that include gold and silica nanoparticles, quantum dots and DNA along with countless other forms of nanotechnology have been investigated regarding their usefulness in advancing molecular diagnostics. Other small scaled materials like viruses and proteins also have potential for use as molecular diagnostic tools. Information obtained from nanotechnology based diagnostics can be stored and manipulated using bioinformatics software. More advanced nanotechnology based diagnostic procedures for the acquisition of even greater proteomic and genomic knowledge can then be developed along with better ways to fight various diseases. Nanotechnology also has numerous applications besides those related to biotechnology and medicine. In this article, we will discuss and analyze many novel nanotechnology based diagnostic techniques at our disposal today. (author)

  20. Magnetic nanoparticles for theragnostics

    Science.gov (United States)

    Shubayev, Veronica I.; Pisanic, Thomas R.; Jin, Sungho

    2009-01-01

    Engineered magnetic nanoparticles (MNPs) represent a cutting-edge tool in medicine because they can be simultaneously functionalized and guided by a magnetic field. Use of MNPs has advanced magnetic resonance imaging (MRI), guided drug and gene delivery, magnetic hyperthermia cancer therapy, tissue engineering, cell tracking and bioseparation. Integrative therapeutic and diagnostic (i.e., theragnostic) applications have emerged with MNP use, such as MRI-guided cell replacement therapy or MRI-based imaging of cancer-specific gene delivery. However, mounting evidence suggests that certain properties of nanoparticles (e.g., enhanced reactive area, ability to cross cell and tissue barriers, resistance to biodegradation) amplify their cytotoxic potential relative to molecular or bulk counterparts. Oxidative stress, a 3-tier paradigm of nanotoxicity, manifests in activation of reactive oxygen species (ROS) (tier I), followed by a pro-inflammatory response (tier II) and DNA damage leading to cellular apoptosis and mutagenesis (tier III). In vivo administered MNPs are quickly challenged by macrophages of the reticuloendothelial system (RES), resulting in not only neutralization of potential MNP toxicity but also reduced circulation time necessary for MNP efficacy. We discuss the role of MNP size, composition and surface chemistry in their intracellular uptake, biodistribution, macrophage recognition and cytotoxicity, and review current studies on MNP toxicity, caveats of nanotoxicity assessments and engineering strategies to optimize MNPs for biomedical use. PMID:19389434

  1. Surface effects in metallic iron nanoparticles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Linderoth, Søren

    1994-01-01

    Nanoparticles of metallic iron on carbon supports have been studied in situ by use of Mossbauer spectroscopy. The magnetic anisotropy energy constant increases with decreasing particle size, presumably because of the influence of surface anisotropy. Chemisorption of oxygen results in formation...... of a surface layer with magnetic hyperfine fields similar to those of thicker passivation layers, and with a ferromagnetic coupling to the spins in the core of the particles. In contrast, thicker passivation layers have a noncollinear spin structure....

  2. In-flight Diagnostic capability for Crew Health by DESI-mass spectrometry

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop a flight-compatible, direct analysis mass spectrometer that can enable in situ diagnostic analyses for crew health and...

  3. Uranium in situ leaching

    International Nuclear Information System (INIS)

    1993-09-01

    Despite the depressed situation that has affected the uranium industry during the past years, the second Technical Committee Meeting on Uranium In Situ Leaching, organized by the International Atomic Energy Agency and held in Vienna from 5 to 8 October 1992, has attracted a relatively large number of participants. A notable development since the first meeting was that the majority of the contributions came from the actual operators of in situ leaching uranium production. At the present meeting, presentations on operations in the USA were balanced by those of the eastern European and Asian countries. Contributions from Bulgaria, China, Czechoslovakia, Germany (from the operation in the former German Democratic Republic), the Russian Federation and Uzbekistan represent new information not commonly available. In situ leach mining is defined in one of the paper presented as a ''mining method where the ore mineral is preferentially leached from the host rock in place, or in situ, by the use of leach solutions, and the mineral value is recovered. Refs, figs and tabs

  4. Sex in situ

    DEFF Research Database (Denmark)

    Krøgholt, Ida

    2017-01-01

    Sex er en del af vores sociale praksis og centralt for det, vi hver især er. Men bortset fra pornoindustrien, har vi ikke mange muligheder for at få adgang til billeder af sex. Teater Nordkrafts forestilling Sex in situ vil gøre seksuelle billeder til noget, der kan deles, udveksles og tales om, og...

  5. In Situ Cometary Cosmochemistry

    Science.gov (United States)

    Wright, I. P.; Andrews, D. J.; Barber, S. J.; Sheridan, S.; Morgan, G. H.; Morse, A. D.

    2013-09-01

    In 2014 the Rosetta space mission arrives at comet 67P. Herein we describe the ambitions of one of the instruments, Ptolemy, included on the lander. Our aim is to make in situ measurements of isotopic compositions of elements such as H, C, N and O.

  6. Multifunctional gold nanoparticles for diagnosis and therapy of disease

    Science.gov (United States)

    Mieszawska, Aneta J.; Mulder, Willem J. M.; Fayad, Zahi A.

    2013-01-01

    Gold nanoparticles (AuNPs) have a number of physical properties that make them appealing for medical applications. For example, the attenuation of X-rays by gold nanoparticles has led to their use in computed tomography imaging and as adjuvants for radiotherapy. AuNPs have numerous other applications in imaging, therapy and diagnostic systems. The advanced state of synthetic chemistry of gold nanoparticles offers precise control over physicochemical and optical properties. Furthermore gold cores are inert and are considered to be biocompatible and non-toxic. The surface of gold nanoparticles can easily be modified for a specific application and ligands for targeting, drugs or biocompatible coatings can be introduced. AuNPs can be incorporated into larger structures such as polymeric nanoparticles or liposomes that deliver large payloads for enhanced diagnostic applications, efficiently encapsulate drugs for concurrent therapy or add additional imaging labels. This array of features has led to the afore-mentioned applications in biomedical fields, but more recently in approaches where multifunctional gold nanoparticles are used for multiple methods, such as concurrent diagnosis and therapy, so called theranostics. The following review covers basic principles and recent findings in gold nanoparticle applications for imaging, therapy and diagnostics, with a focus on reports of multifunctional AuNPs. PMID:23360440

  7. Novel thermogelling dispersions of polymer nanoparticles for controlled protein release.

    Science.gov (United States)

    Cai, Tong; Hu, Peter D; Sun, Manwu; Zhou, Jun; Tsai, Yi-Ting; Baker, David; Tang, Liping

    2012-11-01

    A novel poly(oligo(ethylene glycol) methyl ether methacrylate-co-oligo(ethylene glycol) ethyl ether methacrylate)-poly(acrylic acid) interpenetrating network (IPN) nanoparticle was synthesized. The temperature-responsive properties of the IPN nanoparticles were investigated by a dynamic light scattering method. Atomic force microscopic images confirmed the homogenous and monodisperse morphology of the IPN nanoparticles. Both visual observation and viscosity testing demonstrated that the IPN nanoparticles exhibit thermogelling properties at body temperature, 37 °C. Subsequent studies verified that such temperature-sensitive properties of IPN nanoparticles allow their ease of injection and then slow release of model proteins, both in vitro and in vivo. Histological analysis showed that our IPN implants exerted minimal inflammation following subcutaneous implantation. Our results support the idea that, by simply mixing with proteins of interest, the novel IPN nanoparticles can be used to form in situ thermogelling devices for controlled protein release. This paper discusses a temperature responsive interpenetrating network (IPN) polymeric nanoparticle that can be used to form in situ thermogelling devices for controlled protein release by simply mixing them with proteins of interest. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Fabrication of superhydrophobic fluorinated silica nanoparticles for multifunctional liquid marbles

    Science.gov (United States)

    Shang, Qianqian; Hu, Lihong; Hu, Yun; Liu, Chengguo; Zhou, Yonghong

    2018-01-01

    A facile one-pot method for the fabrication of superhydrophobic fluorinated silica nanoparticles is reported. Fluorinated aggregated silica (A-SiO2/FAS) nanoparticles were synthesized by controlling the nanoparticles assembly, in situ fixation and overgrowth of particle seeds with the assist of tetraethoxysilane (TEOS) in ethanol/water solution and then modification with fluoroalkylsilane (FAS) molecules. Such kind of A-SiO2/FAS nanoparticles showed superhydrophobicity and was not wetted by water, thus it could be served as the encapsulating shells to manipulate liquid droplets. Liquid marbles fabricated from A-SiO2/FAS nanoparticles were used for ammonia gas sensing or emitting by taking advantage of the porosity and superhydrophobicity of the liquid marble shells. In addition, the posibility of A-SiO2/FAS-based liquid marbles as microreactor for dopamine polymerization also was explored.

  9. In Situ Mass Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The In Situ Mass Spectrometer projects focuses on a specific subsystem to leverage advanced research for laser-based in situ mass spectrometer development...

  10. In Situ Electron Microscopy of Lactomicroselenium Particles in Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Gabor Nagy

    2016-06-01

    Full Text Available Electron microscopy was used to test whether or not (a in statu nascendi synthesized, and in situ measured, nanoparticle size does not differ significantly from the size of nanoparticles after their purification; and (b the generation of selenium is detrimental to the bacterial strains that produce them. Elemental nano-sized selenium produced by probiotic latic acid bacteria was used as a lactomicroselenium (lactomicroSel inhibitor of cell growth in the presence of lactomicroSel, and was followed by time-lapse microscopy. The size of lactomicroSel produced by probiotic bacteria was measured in situ and after isolation and purification. For these measurements the TESLA BS 540 transmission electron microscope was converted from analog (aTEM to digital processing (dTEM, and further to remote-access internet electron microscopy (iTEM. Lactobacillus acidophilus produced fewer, but larger, lactomicroSel nanoparticles (200–350 nm than Lactobacillus casei (L. casei, which generated many, smaller lactomicroSel particles (85–200 nm and grains as a cloudy, less electrodense material. Streptococcus thermophilus cells generated selenoparticles (60–280 nm in a suicidic manner. The size determined in situ in lactic acid bacteria was significantly lower than those measured by scanning electron microscopy after the isolation of lactomicroSel particles obtained from lactobacilli (100–500 nm, but higher relative to those isolated from Streptococcus thermopilus (50–100 nm. These differences indicate that smaller lactomicroSel particles could be more toxic to the producing bacteria themselves and discrepancies in size could have implications with respect to the applications of selenium nanoparticles as prebiotics.

  11. Silver Nanoparticle Transport Through Soil: Illuminating the Pore-Scale Processes

    Science.gov (United States)

    Molnar, I. L.; Willson, C. S.; Gerhard, J.; O'Carroll, D. M.

    2015-12-01

    For nanoparticle transport through soil, the pore-scale (i.e., tens to hundreds of grains and pores) is a crucial intermediate scale which links nanoparticle-surface interactions with field-scale transport behaviour. However, very little information exists on how nanoparticles behave within real three-dimensional pore spaces. As a result, pore-scale processes are poorly characterized for nanoparticle systems and, subsequently, continuum-scale transport models struggle to describe commonly observed 'anomalous' behaviour such as extended tailing. This knowledge gap is due to two primary factors: an inability to experimentally observe nanoparticles within real pore spaces, and the computationally expensive models required to simulate nanoparticle movement. However, due to recent advances in Synchrotron X-Ray Computed Microtomography (SXCMT), it is now possible to quantify in-situ pore-scale nanoparticle concentrations during transport through real 3-dimensional porous media [1]. Employing this SXCMT quantification method to examine real nanoparticle/soil transport experiments has yielded new insights into the pore-scale processes governing nanoparticle transport. By coupling SXCMT nanoparticle quantification method with Computational Fluid Dynamics (CFD) simulations we are able to construct a better picture of how nanoparticles flow through real pore spaces. This talk presents SXCMT/CFD analyses of three silver nanoparticle transport experiments. Silver nanoparticles were flushed through three different sands to characterize the influence of grain distribution and retention rates on pore-scale flow and transport processes. These CFD/SXCMT analyses illuminate how processes such as temporary hydraulic retention govern nanoparticle transport. In addition, the observed distributions of pore water velocities and nanoparticle mass flow rates challenge the standard conceptual model of nanoparticle transport, suggesting that pore-scale processes require explicit consideration

  12. Diagnostic accuracy of organ electrodermal diagnostics

    African Journals Online (AJOL)

    ll Diagnostic methods based upon measurements of electrical potential, resistance and impedance of these zones have been proposed; however, their diagnostic accuracy has not been proven and reproducibility has not been consistent. Some of these methods utilise specific bio-electrical properties of acupuncture points.

  13. Therapeutic and diagnostic nanomaterials

    CERN Document Server

    Devasena T

    2017-01-01

    This brief highlights nanoparticles used in the diagnosis and treatment of prominent diseases and toxic conditions. Ecofriendly methods which are ideal for the synthesis of medicinally valued nanoparticles are explained and the characteristic features of these particles projected. The role of these particles in the therapeutic field, and the induced biological changes in some diseases are discussed. The main focus is on inflammation, oxidative stress and cellular membrane integrity alterations. The effect of nanoparticles on these changes produced by various agents are highlighted using in vitro and in vivo models. The mechanism of nanoparticles in ameliorating the biological changes is supported by relevant images and data. Finally, the brief demonstrates recent developments on the use of nanoparticles in diagnosis or sensing of some biological materials and biologically hazardous environmental materials.

  14. Sustainable steric stabilization of colloidal titania nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Elbasuney, Sherif, E-mail: sherif_basuney2000@yahoo.com

    2017-07-01

    Graphical abstract: Controlled surface properties of titania nanoparticles via surface modification, flocculation from aqueous phase (a), stabilization in aqueous phase (b), extraction to organic phase (c). - Highlights: • Complete change in surface properties of titania nanoparticles from hydrophilic to hydrophobic. • Harvesting the formulated nanoparticles from the aqueous phase to the organic phase. • Exclusive surface modification in the reactor during nanoparticle synthesis. • Sustainable stabilization of titania nanoparticles in aqueous media with polar polymeric dispersant. - Abstract: A route to produce a stable colloidal suspension is essential if mono-dispersed particles are to be successfully synthesized, isolated, and used in subsequent nanocomposite manufacture. Dispersing nanoparticles in fluids was found to be an important approach for avoiding poor dispersion characteristics. However, there is still a great tendency for colloidal nanoparticles to flocculate over time. Steric stabilization can prevent coagulation by introducing a thick adsorbed organic layer which constitutes a significant steric barrier that can prevent the particle surfaces from coming into direct contact. One of the main features of hydrothermal synthesis technique is that it offers novel approaches for sustainable nanoparticle surface modification. This manuscript reports on the sustainable steric stabilization of titanium dioxide nanoparticles. Nanoparticle surface modification was performed via two main approaches including post-synthesis and in situ surface modification. The tuneable hydrothermal conditions (i.e. temperature, pressure, flow rates, and surfactant addition) were optimized to enable controlled steric stabilization in a continuous fashion. Effective post synthesis surface modification with organic ligand (dodecenyl succinic anhydride (DDSA)) was achieved; the optimum surface coating temperature was reported to be 180–240 °C to ensure DDSA ring opening

  15. Antimicrobial Polymers with Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Humberto Palza

    2015-01-01

    Full Text Available Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms.

  16. Ratiometric Afterglow Nanothermometer for Simultaneous in Situ Bioimaging and Local Tissue Temperature Sensing

    NARCIS (Netherlands)

    Yang, J.; Liu, Y.; Zhao, Y.; Gong, Z.; Zhang, M.; Yan, D.; Zhu, H.; Liu, C.; Xu, C.; Zhang, H.

    2017-01-01

    Simultaneous in situ bioimage tracing and temperature sensing have been two of the foci of modern biomedicine that have given birth to designing novel luminescent nanothermometers with dual functions. To minimize the disadvantages of existing approaches, like the surface effect of nanoparticles,

  17. Ex situ synthesis of G/α-Fe2O3 nanocomposite and its catalytic effect ...

    Indian Academy of Sciences (India)

    G/ α -Fe 2 O 3 nanocomposite was prepared using ex situ synthesis in the presence of α -Fe 2 O 3 nanoparticles and GO solution. The characterization of the as-prepared materialswas performed using X-ray diffraction analyses and Fourier transform infrared spectroscopy; their morphology wasinvestigated by scanning ...

  18. Functionalized TiO2nanoparticles by single-step hydrothermal synthesis: the role of the silane coupling agents.

    Science.gov (United States)

    Dalod, Antoine R M; Henriksen, Lars; Grande, Tor; Einarsrud, Mari-Ann

    2017-01-01

    A simple, robust and versatile hydrothermal synthesis route to in situ functionalized TiO 2 nanoparticles was developed using titanium(IV) isopropoxide as Ti-precursor and selected silane coupling agents (3-aminopropyltriethoxysilane (APTES), 3-(2-aminoethylamino)propyldimethoxymethylsilane (AEAPS), and n -decyltriethoxysilane (DTES)). Spherical nanoparticles (ca. 9 nm) with narrow size distribution were obtained by using DTES or by synthesis performed without silane coupling agents. Rod-like nanoparticles along with 9 nm spherical nanoparticles were formed using aminosilane coupling agents because of a combination of oriented attachment of nanoparticles and specific adsorption of the aminosilane on crystallographic faces of anatase nanoparticles. The nanoparticles were functionalized in situ and became hydrophobic as silanes reacted to form covalent bonds on the surface of TiO 2 . The versatility of the aqueous synthesis route was demonstrated, and by selecting the type of silane coupling agent the surface properties of the TiO 2 nanoparticles could be tailored. This synthesis route has been further developed into a two-step synthesis to TiO 2 -SiO 2 core-shell nanoparticles. Combustion of the silane coupling agents up to 700 °C leads to the formation of a nanometric amorphous SiO 2 layer, preventing growth and phase transition of the in situ functionalized nanoparticles.

  19. Direct observation of two-step crystallization in nanoparticle superlattice formation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jungwon; Zheng, Haimei; Lee, Won Chul; Geissler, Phillip L.; Rabani, Eran; Alivisatos, A. Paul

    2011-10-06

    Direct imaging of nanoparticle solutions by liquid phase transmission electron microscopy has enabled unique in-situ studies of nanoparticle motion and growth. In the present work, we report on real-time formation of two-dimensional nanoparticle arrays in the very low diffusive limit, where nanoparticles are mainly driven by capillary forces and solvent fluctuations. We find that superlattice formation appears to be segregated into multiple regimes. Initially, the solvent front drags the nanoparticles, condensing them into an amorphous agglomerate. Subsequently, the nanoparticle crystallization into an array is driven by local fluctuations. Following the crystallization event, superlattice growth can also occur via the addition of individual nanoparticles drawn from outlying regions by different solvent fronts. The dragging mechanism is consistent with simulations based on a coarse-grained lattice gas model at the same limit.

  20. Discrete Dynamics of Nanoparticle Channelling in Suspended Graphene

    DEFF Research Database (Denmark)

    Booth, Tim; Pizzocchero, Filippo; Andersen, Henrik

    2011-01-01

    We have observed a previously undescribed stepwise oxidation of mono- and few layer suspended graphene by silver nanoparticles in situ at subnanometer scale in an environmental transmission electron microscope. Over the range of 600–850 K, we observe crystallographically oriented channelling...

  1. Graphene Edges Dictate the Morphology of Nanoparticles during Catalytic Channeling

    DEFF Research Database (Denmark)

    Pizzocchero, Filippo; Vanin, Marco; Kling, Jens

    2014-01-01

    We perform in-situ transmission electron microscopy (TEM) experiments of silver nanoparticles channeling on mono-, bi-, and few-layer graphene and discover that the interactions in the one-dimensional particle–graphene contact line are sufficiently strong so as to dictate the three...

  2. DURIP 98-99: Molecular Beam Epitaxial Growth and In Situ Characterization of Phase Separated Optoelectronic Semiconductors

    National Research Council Canada - National Science Library

    Millunchick, J. Mirecki

    1999-01-01

    This proposal requested funding to procure a Molecular Beam Epitaxy (MBE) chamber with extensive in situ diagnostic capabilities to study phase separation of III-V semiconductor alloys during epitaxial growth...

  3. Click synthesis of podand triazole-linked gold nanoparticles as highly selective and sensitive colorimetric probes for lead(II) ions.

    Science.gov (United States)

    Li, Haibing; Zheng, Qiuling; Han, Cuiping

    2010-06-01

    Podand triazole-linked gold nanoparticles were designed via an in situ'click' reaction. The resulting gold nanoparticles were characterized by UV-vis spectroscopy, FT-IR spectroscopy, transmission electron microscopy (TEM). Podand triazole-linked gold nanoparticles were utilized as colorimetric probes for Pb(2+)via Pb(2+)-induced gold nanoparticle aggregation which incorporates two podand molecules from different nanoparticles forming an intermolecule type of association. Moreover, the application of the resulting gold nanoparticles to evaluate the exceeding standard of lead ions in drinking water and leaded paint was investigated.

  4. In-Situ Simulation

    DEFF Research Database (Denmark)

    Bjerregaard, Anders Thais; Slot, Susanne; Paltved, Charlotte

    2015-01-01

    offered in situ simulation faculty with a model for integrating reported critical incidents and adverse events with contextual needs analysis and short-term observations. Furthermore the research group is working on detailing the barriers of in situ simulation such as resources for team training despite...... emergencies. It contains 12 questions, which are rated using a five-point scale, and covers four categories; leadership, teamwork and task management, and an overall score on team performance. Results: 16 simulations were conducted with 16 different teams of 10 doctors and 32 nurses. First, this study took...... of handovers. The team performance varied greatly according to how well the team members knew each other professionally as confirmed by video recordings. SAQ, and TEAM observational data are being analyzed by the research group with focus on correlation with teamwork and handovers. In summary, this study...

  5. Thioaptamer Diagnostic System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AM Biotechnologies (AM) will develop a diagnostic system in response to SBIR Topic X10.01 Reusable Diagnostic Lab Technology that will simultaneously detect and...

  6. Interaction of Colloidal Gold Nanoparticles with Model Serum Proteins: The Nanoparticle-Protein 'Corona' from a PhysicoChemical Viewpoint

    Science.gov (United States)

    Dominguez Medina, Sergio

    When nanoparticles come in contact with biological fluids they become coated with a mixture of proteins present in the media, forming what is known as the nanoparticle-protein 'corona'. This corona changes the nanoparticles' original surface properties and plays a central role in how these get screened by cellular receptors. In the context of biomedical research, this presents a bottleneck for the transition of nanoparticles from research laboratories to clinical settings. It is therefore fundamental to probe these nanoparticle-protein interactions in order to understand the different physico-chemical mechanisms involved. This thesis is aimed to investigate the exposure of colloidal gold nanoparticles to model serum proteins, particularly serum albumin, the main transporter of molecular compounds in the bloodstream of mammals. A set of experimental tools based on optical microscopy and spectroscopy were developed in order to probe these interactions in situ. First, the intrinsic photoluminescence and elastic scattering of individual gold nanoparticles were investigated in order to understand its physical origin. These optical signals were then used to measure the size of the nanoparticles while in Brownian diffusion using fluctuation correlation spectroscopy. This spectroscopic tool was then applied to detect the binding of serum albumin onto the nanoparticle surface, increasing its hydrodynamic size. By performing a binding isotherm as a function of protein concentration, it was determined that serum albumin follows an anti-cooperative binding mechanism on negatively charged gold nanoparticles. This protein monolayer substantially enhanced the stability of the colloid, preventing their aggregation in saline solutions with ionic strength higher than biological media. Cationic gold nanoparticles in contrast, aggregated when serum albumin was present at a low protein-to-nanoparticle ratio, but prevented aggregation if exposed in excess. Single-molecule fluorescence

  7. Nanoparticles for multimodal in vivo imaging in nanomedicine

    Directory of Open Access Journals (Sweden)

    Key J

    2014-01-01

    Full Text Available Jaehong Key,1–3 James F Leary1–41Weldon School of Biomedical Engineering, 2Birck Nanotechnology Center, 3Bindley Bioscience Center, 4College of Veterinary Medicine, Purdue University, West Lafayette, IN, USAAbstract: While nanoparticles are usually designed for targeted drug delivery, they can also simultaneously provide diagnostic information by a variety of in vivo imaging methods. These diagnostic capabilities make use of specific properties of nanoparticle core materials. Near-infrared fluorescent probes provide optical detection of cells targeted by real-time nanoparticle-distribution studies within the organ compartments of live, anesthetized animals. By combining different imaging modalities, we can start with deep-body imaging by magnetic resonance imaging or computed tomography, and by using optical imaging, get down to the resolution required for real-time fluorescence-guided surgery.Keywords: nanomedicine, nanoparticles, multimodal imaging, CT, MRI, NIRF, PET, cancer

  8. Solid Tumor-Targeting Theranostic Polymer Nanoparticle in Nuclear Medicinal Fields

    Directory of Open Access Journals (Sweden)

    Akira Makino

    2014-01-01

    Full Text Available Polymer nanoparticles can be prepared by self-assembling of amphiphilic polymers, and various types of molecular assemblies have been reported. In particular, in medicinal fields, utilization of these polymer nanoparticles as carriers for drug delivery system (DDS has been actively tried, and some nanoparticulate drugs are currently under preclinical e