Fabrication of gelatin-siloxane fibrous mats via sol-gel and electrospinning procedure and its application for bone tissue engineering

International Nuclear Information System (INIS)

Ren Lei; Wang Jun; Yang Fangyu; Wang Lin; Wang Dong; Wang Tianxiao; Tian Miaomiao

2010-01-01

Our strategy is to design and fabricate biomimetic and bioactive scaffolds that resemble the native extracellular matrix as closely as possible so as to create conducive living milieu that will induce cell to function naturally. In the present study, gelatin/siloxane (GS) hybrids were prepared by a sol-gel processing, and electrospinning technique was used to fabricate GS fibrous mats to support the growth of bone marrow-derived mesenchymal stem cells (BMSCs) for tissue engineering of bone. The results indicate that the porous structure and fiber size of the GS fibrous mats can be fine tuned by varying the viscosity of GS precursor solution. Additionally, the Ca 2+ -containing GS fibrous mats biomimetically deposited apatite in a simulated body fluid (SBF), as well as stimulating its BMSCs proliferation and differentiation in vitro, thereby dignifying its in vitro bioactivity.

Bioactivity of noble metal nanoparticles decorated with biopolymers and their application in drug delivery.

Science.gov (United States)

Rai, Mahendra; Ingle, Avinash P; Gupta, Indarchand; Brandelli, Adriano

2015-12-30

The unique properties of nanomaterials can be applied to solve different problems including new ways of drug delivery. Noble metal nanoparticles are most promising because they have been used for medicinal purposes since ancient time. It is evident from the past studies that the metallic nanoparticles are much more effective against various microorganisms when compared to their conventional counterparts. However, decoration of such nanoparticles with biomaterials add more advantages to their antimicrobial activity. Decoration of metal nanoparticles with biopolymers is a quite new area of research. Studies performed hitherto shown that nanoparticles of noble metals like silver, gold and platinum demonstrated better antibacterial, antifungal and antiviral activities when conjugated with biopolymers. The development of such technology has potential to develop materials that are more effective in the field of health science. Considering the importance and uniqueness of this concept, the present review aims to discuss the use of biopolymer-decorated metal nanoparticles for combating various diseases caused by microbial pathogens. Moreover, the nanotoxicity aspect has also been discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Understanding the significance variables for fabrication of fish gelatin nanoparticles by Plackett-Burman design

Science.gov (United States)

Subara, Deni; Jaswir, Irwandi; Alkhatib, Maan Fahmi Rashid; Noorbatcha, Ibrahim Ali

2018-01-01

The aim of this experiment is to screen and to understand the process variables on the fabrication of fish gelatin nanoparticles by using quality-design approach. The most influencing process variables were screened by using Plackett-Burman design. Mean particles size, size distribution, and zeta potential were found in the range 240±9.76 nm, 0.3, and -9 mV, respectively. Statistical results explained that concentration of acetone, pH of solution during precipitation step and volume of cross linker had a most significant effect on particles size of fish gelatin nanoparticles. It was found that, time and chemical consuming is lower than previous research. This study revealed the potential of quality-by design in understanding the effects of process variables on the fish gelatin nanoparticles production.

Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

Science.gov (United States)

Jeong, Lim; Park, Won Ho

2014-01-01

Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO3)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO3/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO3 and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO3. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

Boron nitride nanosheets decorated with silver nanoparticles through mussel-inspired chemistry of dopamine

International Nuclear Information System (INIS)

Roy, Arup Kumer; In, Insik; Park, Byoungnam; Lee, Kang Seok; Park, Sung Young

2014-01-01

Boron nitride nanosheet (BNNS) decorated with silver nanoparticles (AgNPs) was successfully synthesized via mussel-inspired chemistry of dopamine. Poly(dopamine)-functionalized BNNS (PDA-BNNS) was prepared by adding dopamine into the aqueous dispersion of hydroxylated BNNS (OH-BNNS) at alkaline condition. AgNPs were decorated on PDA-BNNS through spontaneous reduction of silver cations by catechol moieties of a PDA layer on BNNS, resulting in AgNP-BNNS with good dispersion stability. Incorporation of PDA on BNNS not only played a role as a surface functionalization method of BNNS, but also provided a molecular platform for creating very sophisticated two-dimensional (2D) BNNS-based hybrid nanomaterials such as metal nanoparticle-decorated BNNS. (paper)

Physicochemical and antifungal properties of bio-nanocomposite film based on gelatin-chitin nanoparticles.

Science.gov (United States)

Sahraee, Samar; Milani, Jafar M; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2017-04-01

The gelatin-based nanocomposite films containing chitin nanoparticles (N-chitin) with concentrations of 0, 3, 5 and 10% were prepared and their physical, thermal and anti-microbial properties were investigated. Scanning electron microscopy (SEM) micrographs showed that N-chitin size distribution was around 60-70nm which dispersed appropriately at low concentration in gelatin matrix. The results showed that incorporation of N-chitin significantly influenced apparent color and transparency of the gelatin films. The reduced water vapor permeability (WVP) and solubility and higher surface hydrophobicity of the nanocomposite films were obtained by enhancing N-chitin concentration in film formulation. The use of N-chitin up to 5% concentration in the gelatin based nanocomposite film led to improved mechanical properties. Also, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved stability of nanocomposite films against melting and degradation at high temperatures in comparison to neat gelatin film. The well compatibility of chitin nanoparticles with gelatin polymer was concluded from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) plots. Finally, the gelatin based nanocomposite films had anti-fungal properties against Aspergillus niger in the contact surface zone. Increasing the concentration of N-chitin up to 5% enlarged inhibition zone diameter, but the nanocomposite film containing 10% N-chitin showed smaller inhibition zone. Copyright © 2016 Elsevier B.V. All rights reserved.

P25 nanoparticles decorated on titania nanotubes arrays as effective drug delivery system for ibuprofen

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhang; Xie, Chunlin; Luo, Fei; Li, Ping; Xiao, Xiufeng, E-mail: xfxiao@fjnu.edu.cn

2015-01-01

Highlights: • P25 nanoparticles decorated on titania nanotube arrays were prepared by hydrothermal treatment. • P25 nanoparticles were conducive to improve the loading effect of ibuprofen into nanotube arrays. • The diameters of the decorated nanotubes were decrease markedly which led to an effective and prolonged drug release. - Abstract: In this study, uniformly distributed layer of P25 nanoparticles (NPs) decorated on titania (TiO{sub 2}) nanotubes (TNTs) arrays was prepared in a teflon-lined stainless steel autoclave by the hydrothermal treatment. To investigate the influence of the P25 concentration, different concentrations of P25 NPs were added into the solution to obtain the optimal decorative effect. TNTs decorated with P25 (TNTs–P25) and TNTs without P25 decorated on its surface were loaded with ibuprofen (IBU) via vacuum drying and its release properties were investigated. The samples were characterized by field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that P25 NPs were successfully decorated on the surface of TNTs by hydrothermal method and the optimal concentration was found to be 7.5 × 10{sup −4} M. P25 NPs decorated on TNTs led to a significant increase in the specific surface area of TNTs which was conducive to improve the loading effect of IBU. Importantly, the diameters of the decorated nanotubes were reduced to 100 ± 10 nm and the increase in roughness led to an effective and prolonged drug release.

Reduced graphene oxide decorated with Fe doped SnO{sub 2} nanoparticles for humidity sensor

Energy Technology Data Exchange (ETDEWEB)

Toloman, D. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Popa, A., E-mail: popa@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Stan, M.; Socaci, C.; Biris, A.R. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Katona, G. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, 400028 Cluj-Napoca (Romania); Tudorache, F. [Interdisciplinary Research Department – Field Science & RAMTECH, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania); Petrila, I. [Interdisciplinary Research Department – Field Science & RAMTECH, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania); Faculty of Automatic Control and Computer Engineering, Gheorghe Asachi Technical University, 27 Dimitrie Mangeron Street, 700050 Iasi (Romania); Iacomi, F. [Faculty of Physics, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania)

2017-04-30

Highlights: • Reduced graphene oxide decorated with Fe doped SnO{sub 2} nanoparticles were synthesized. • The decoration of rGO layers with SnO{sub 2}:Fe nanoparticles was highlited by TEM. • The reduction of graphene oxide was evidenced using XRD and FT-IR. • Sensitivity tests for relative humidity (RH) were carried out. • The composite sensor exhibited enhanced sensing response as compared with Fe:SnO{sub 2}. - Abstract: Reduced graphene oxide (rGO) decorated with Fe doped SnO{sub 2} nanoparticles were fabricated via the electrostatic interaction between positively charged modified Fe-doped SnO{sub 2} oxide and negatively charged graphene oxide (GO) in the presence of poly(allylamine) hydrochloride (PAH). The decoration of rGO layers with SnO{sub 2}:Fe nanoparticles was highlited by TEM microsopy. For composite sample the diffraction patterns coincide well with those of SnO{sub 2}:Fe nanoparticles. The reduction of graphene oxide was evidenced using XRD and FT-IR spectroscopy. The formation of SnO{sub 2}:Fe-PAH-graphene composites was confirmed by FT-IR, Raman and EPR spectroscopy. Sensitivity tests for relative humidity (RH) measurements were carried out at five different concentrations of humid air at room temperature. The prepared composite sensor exhibited a higher sensing response as compared with Fe:SnO{sub 2} nanoparticles.

Effect of Some Synthetic Parameters on Size and Polydispersity Index of Gelatin Nanoparticles Cross-Linked by CDI/NHS System

Directory of Open Access Journals (Sweden)

S. Zinatloo-Ajabshir

2015-04-01

Full Text Available In our previous work, the effect of use of a water soluble CDI/NHS system as nontoxic cross-linking agent on fabrication of gelatin nanoparticles was investigated. In this research, the effect of variation in some synthetic parameters of gelatin nanoparticles cross-linked by CDI/NHS system such as type of gelatin and formulation of cross- linking agent on their size and distribution was examined. The conventional two step desolvation method was used for preparation of gelatin nanoparticles. The morphology, mean size and size distribution of the formed nanoparticles were evaluated and compared with each other. In addition, intrinsic viscosities of all the nanoparticles were measured and compared under different conditions. The results showed that the presence of more NHS and absence of NHS catalyst in CDI/NHS system lead to the large particle size and broad size distribution of nanoparticles that were attributed to the fast and slow cross-linking rate, respectively.

Ether gas-sensor based on Au nanoparticles-decorated ZnO microstructures

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Roberto López

Full Text Available An ether gas-sensor was fabricated based on gold nanoparticles (Au-NPs decorated zinc oxide microstructures (ZnO-MS. Scanning electron microscope (SEM and high-resolution transmission electron microscope (HRTEM measurements were performed to study morphological and structural properties, respectively, of the ZnO-MS. The gas sensing response was evaluated in a relatively low temperature regime, which ranged between 150 and 250 °C. Compared with a sensor fabricated from pure ZnO-MS, the sensor based on Au-NPs decorated ZnO-MS showed much better ether gas response at the highest working temperature. In fact, pure ZnO-MS based sensor only showed a weak sensitivity of about 25%. The improvement of the ether gas response for sensor fabricated with Au-NPs decorated ZnO-MS was attributed to the catalytic activity of the Au-NPs. Keywords: ZnO microstructures, Au nanoparticles, Ether, Gas sensor

Spontaneously Bi decorated carbon supported Pd nanoparticles for formic acid electro-oxidation

International Nuclear Information System (INIS)

Bauskar, Akshay S.; Rice, Cynthia A.

2013-01-01

Highlights: • Selective decoration of Bi onto commercial Pd/C is carried out by a simple gas controlled surface potential modulation technique. • Bi decorated Pd/C catalyst exhibits higher and sustained formic acid oxidation activity presumably via the electronic effect. • Shielding of Pd atoms by Bi increases long term stability. • Formic acid electro-oxidation current increased by 121% at 0.2 V vs. RHE. -- Abstract: The activity and stability of carbon supported palladium (Pd/C) nanoparticles decorated with a submonolayer of bismuth (Bi) for formic acid (FA) electro-oxidation was investigated herein. The FA electro-oxidation activity enhancement of Bi decorated Pd/C was evaluated electrochemically using a rotating disk electrode configuration by linear sweep voltammetric and chronoamperometric measurements. Commercial Pd/C was decorated by irreversible adsorption of Bi via a simple gas controlled surface potential modulation technique, and the coverage of Bi adatoms as measured by cyclic voltammetry was controlled in the range of 30–87%. An optimal Bi coverage was observed to be 40%, resulting in a favorable decrease in the FA onset potential by greater than 0.1 V and increase in electro-oxidation current density from 0.25 mA cm −2 SA to 0.55 mA cm −2 SA at 0.2 V vs. RHE, compared to commercial Pd/C. The results indicate that Bi decorated Pd nanoparticles have excellent properties for the electro-oxidation of FA, i.e. high electro-catalytic activity and excellent stability, due to sustained promotion of dehydrogenation pathway attributed to the electronic effect, thereby promoting FA adsorption in the CH-down orientation. Based on no significant shifting in the CO stripping peak position, minimal impact of Bi on the Pd-CO bond strength is observed. Chronoamperometry results show much better long-term electro-catalytic activity for Bi decorated Pd nanoparticles attributed to shielding of surface Pd atoms by Bi and reducing Pd dissolution

Enhanced photoelectrochemical properties of TiO2 nanorod arrays decorated with CdS nanoparticles

International Nuclear Information System (INIS)

Xie, Zheng; Wang, Weipeng; Liu, Can; Li, Zhengcao; Liu, Xiangxuan; Zhang, Zhengjun

2014-01-01

TiO 2 nanorod arrays (TiO 2 NRAs) sensitized with CdS nanoparticles were fabricated via successive ion layer adsorption and reaction (SILAR), and TiO 2 NRAs were obtained by oxidizing Ti NRAs obtained through oblique angle deposition. The TiO 2 NRAs decorated with CdS nanoparticles exhibited excellent photoelectrochemical and photocatalytic properties under visible light, and the one decorated with 20 SILAR cycles CdS nanoparticles shows the best performance. This can be attributed to the enhanced separation of electrons and holes by forming heterojunctions of CdS nanoparticles and TiO 2 NRAs. This provides a promising way to fabricate the material for solar energy conversion and wastewater degradation. (paper)

Chemical and structural properties of Pd nanoparticle-decorated graphene—Electron spectroscopic methods and QUASES

Energy Technology Data Exchange (ETDEWEB)

Lesiak, B., E-mail: blesiak-orlowska@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Jiricek, P.; Bieloshapka, I. [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 6, 162-53 Prague 6 (Czech Republic)

2017-05-15

Highlights: • Pd-decorated graphene oxide (GO), reduced graphene oxide (RGO), graphite (Gr). • Electron spectroscopy (XPS) aided with QUASES and REELS structural analysis. • Pd nanoparticle size decreases with surface hydrophilicity (oxygen group content). • PdO{sub x} overlayer thickness increases with surface hydrophilicity. • GO reduction, Pd decoration by reduction lead to exfoliated graphene structures. - Abstract: Graphite (Gr) and carbon nanomaterials such as graphene oxide (GO) and reduced graphene oxide (RGO) and those decorated with Pd nanoparticles were investigated by photoelectron spectroscopy (XPS) aided with Quantitative Analysis of Surfaces by Electron Spectroscopy (QUASES) and reflected electron energy loss spectroscopy (REELS). Oxidation of Gr decreased the C/O ratio from 10 (Gr) to 2.2 (GO), whereas reduction of GO by N{sub 2}H{sub 4} increased this ratio to 6.6 (RGO) due to decreasing number of oxygen groups (hydroxyl, epoxy, carbonyl and hydroxyl). Graphene materials and those after Pd decoration had 6–11 average number of layers in stacked nanostructures. Pd decoration using NaBH{sub 4}-reducing agents formed nanoparticles of size 6.9 nm (Pd/Gr) > 5.3 nm (Pd/RGO) > 4.25 nm (Pd/GO), with PdO{sub x} overlayer thickness of 2.20 nm (Pd/GO) > 1.42 nm (Pd/Gr) > 1.20 nm (Pd/RGO), decreased number of oxygen groups and average number of layers. Smaller Pd nanoparticles of larger PdO{sub x} overlayer thickness were observed on highly hydrophilic substrates (functional oxygen groups content). Decoration accompanied by reduction using NaBH{sub 4} led to the removal of water attached by hydrogen bonding to graphene interplanes and the formation of PdO{sub x} overlayer from oxygen functional groups. Nanoparticle size obtained from QUASES was confirmed by Pd 3d{sub 5/2} spectra binding energy and full-width at half maximum. Various chemistry and mechanisms of graphene reduction using N{sub 2}H{sub 4} and NaBH{sub 4} were observed, where Na

Highly Efficient Intracellular Protein Delivery by Cationic Polyethyleneimine-Modified Gelatin Nanoparticles

Directory of Open Access Journals (Sweden)

Ming-Ju Chou

2018-02-01

Full Text Available Intracellular protein delivery may provide a safe and non-genome integrated strategy for targeting abnormal or specific cells for applications in cell reprogramming therapy. Thus, highly efficient intracellular functional protein delivery would be beneficial for protein drug discovery. In this study, we generated a cationic polyethyleneimine (PEI-modified gelatin nanoparticle and evaluated its intracellular protein delivery ability in vitro and in vivo. The experimental results showed that the PEI-modified gelatin nanoparticle had a zeta potential of approximately +60 mV and the particle size was approximately 135 nm. The particle was stable at different biological pH values and temperatures and high protein loading efficiency was observed. The fluorescent image results revealed that large numbers of particles were taken up into the mammalian cells and escaped from the endosomes into the cytoplasm. In a mouse C26 cell-xenograft cancer model, particles accumulated in cancer cells. In conclusion, the PEI-modified gelatin particle may provide a biodegradable and highly efficient protein delivery system for use in regenerative medicine and cancer therapy.

Cosilencing Intestinal Transglutaminase-2 and Interleukin-15 Using Gelatin-Based Nanoparticles in an in Vitro Model of Celiac Disease.

Science.gov (United States)

Attarwala, Husain; Clausen, Valerie; Chaturvedi, Prasoon; Amiji, Mansoor M

2017-09-05

In this study, we have developed a type B gelatin nanoparticle based siRNA delivery system for silencing of intestinal transglutaminase-2 (TG2) and interleukin-15 (IL-15) genes in cultured human intestinal epithelial cells (Caco-2) and murine alveolar macrophage cells (J774A.1). Small interfering RNA (siRNA) targeting the TG2 or IL-15 gene was encapsulated within gelatin nanoparticles using ethanol-water solvent displacement method. Size, charge, and morphology of gelatin nanoparticles were evaluated using a Zetasizer instrument and transmission electron microscopy. siRNA encapsulation efficiency was determined using an siRNA specific stem-loop quantitative polymerase chain reaction (qPCR) assay. Cellular uptake of siRNA-containing gelatin nanoparticles was determined using fluorescent microscopy and stem-loop qPCR assay. siRNA loading in the RISC (RNA-induced silencing complex) was determined by immunoprecipitation of argonaute 2 (AGO2) protein followed by stem-loop qPCR for siRNA quantification. Gene expression analysis of TG2, IL-15, and the proinflammatory cytokines, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ), was performed using qPCR assays. Efficacy of silencing TG2 and IL-15 knockdown was evaluated in an in vitro model of celiac disease by utilizing immunogenic α-gliadin peptide p31-43 in cultured J774A.1 cells. siRNA-containing gelatin nanoparticles were spherical in shape with mean particle size and charge of 217 ± 8.39 nm and -6.2 ± 0.95 mV, respectively. siRNA loading efficiency within gelatin nanoparticles was found to be 89.3 ± 3.05%. Evaluations of cellular uptake using fluorescent microscopy showed rapid internalization of gelatin nanoparticles within 2 h of dosing, with cytosolic localization of delivered siRNA in Caco-2 cells. Gelatin nanoparticles showed greater intracellular siRNA exposure with a longer half-life, when compared to Lipofectamine-mediated siRNA delivery. Approximately 0.1% of total intracellular si

Magnesium nanoparticles with transition metal decoration for hydrogen storage

International Nuclear Information System (INIS)

Pasquini, Luca; Callini, Elsa; Brighi, Matteo; Boscherini, Federico; Montone, Amelia; Jensen, Torben R.; Maurizio, Chiara; Vittori Antisari, Marco; Bonetti, Ennio

2011-01-01

We report on the hydrogen storage behaviour of Mg nanoparticles (NPs) (size range 100 nm–1 μm) with metal-oxide core–shell morphology synthesized by inert gas condensation and decorated by transition metal (TM) (Pd or Ti) clusters via in situ vacuum deposition. The structure and morphology of the as-prepared and hydrogenated NPs is studied by electron microscopy, X-ray diffraction including in situ experiments and X-ray absorption spectroscopy, in order to investigate the relationships with the hydrogen storage kinetics measured by the volumetric Sieverts method. With both Pd and Ti, the decoration deeply improves the hydrogen sorption properties: previously inert NPs exhibit complete hydrogenation with fast transformation kinetics, good stability and reversible gravimetric capacity that can attain 6 wt%. In the case of Pd-decoration, the occurrence of Mg–Pd alloying is observed at high temperatures and in dependence of the hydrogen pressure conditions. These structural transformations modify both the kinetics and thermodynamics of hydride formation, while Ti-decoration has an effect only on the kinetics. The experimental results are discussed in relation with key issues such as the amount of decoration, the heat of mixing between TM and Mg and the binding energy between TM and hydrogen.

Incorporation of mesoporous silica nanoparticles into random electrospun PLGA and PLGA/gelatin nanofibrous scaffolds enhances mechanical and cell proliferation properties

International Nuclear Information System (INIS)

Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Nasri-Nasrabadi, Bijan; Ghaedi, Kamran; Salehi, Hossein; Dolatshahi-Pirouz, Alireza; Arpanaei, Ayyoob

2016-01-01

Poly(lactic-co-glycolic acid) (PLGA) and PLGA/gelatin random nanofibrous scaffolds embedded with different amounts of mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. To evaluate the effects of nanoparticles on the scaffolds, physical, chemical, and mechanical properties as well as in vitro degradation behavior of scaffolds were investigated. The mean diameters of nanofibers were 974 ± 68 nm for the pure PLGA scaffolds vs 832 ± 70, 764 ± 80, and 486 ± 64 for the PLGA/gelatin, PLGA/10 wt% MSNPs, and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The results suggested that the incorporation of gelatin and MSNPs into PLGA-based scaffolds enhances the hydrophilicity of scaffolds due to an increase of hydrophilic functional groups on the surface of nanofibers. With porosity examination, it was concluded that the incorporation of MSNPs and gelatin decrease the porosity of scaffolds. Nanoparticles also improved the tensile mechanical properties of scaffolds. Using in vitro degradation analysis, it was shown that the addition of nanoparticles to the nanofibers matrix increases the weight loss percentage of PLGA-based samples, whereas it decreases the weight loss percentage in the PLGA/gelatin composites. Cultivation of rat pheochromocytoma cell line (PC12), as precursor cells of dopaminergic neural cells, on the scaffolds demonstrated that the introduction of MSNPs into PLGA and PLGA/gelatin matrix leads to improved cell attachment and proliferation and enhances cellular processes. - Highlights: • PLGA-based random nanofibers embedded with mesoporous silica nanoparticles were fabricated using electrospinning method • Incorporation of gelatin and MSNPs into PLGA-based scaffolds increased the hydrophilicity of scaffold • Addition of nanoparticles also improved the tensile mechanical properties of scaffolds • Introduction of MSNPs led to improved cell attachment and proliferation

Incorporation of mesoporous silica nanoparticles into random electrospun PLGA and PLGA/gelatin nanofibrous scaffolds enhances mechanical and cell proliferation properties

Energy Technology Data Exchange (ETDEWEB)

Mehrasa, Mohammad [Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of); Asadollahi, Mohammad Ali, E-mail: ma.asadollahi@ast.ui.ac.ir [Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Nasri-Nasrabadi, Bijan [Department of Chemical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Ghaedi, Kamran [Department of Biology, Faculty of Science, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Salehi, Hossein [Department of Anatomical Sciences, School of Medicine, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Dolatshahi-Pirouz, Alireza [DTU Nanotech, Center for Nanomedicine and Theranostics, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby (Denmark); Arpanaei, Ayyoob, E-mail: arpanaei@yahoo.com [Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of)

2016-09-01

Poly(lactic-co-glycolic acid) (PLGA) and PLGA/gelatin random nanofibrous scaffolds embedded with different amounts of mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. To evaluate the effects of nanoparticles on the scaffolds, physical, chemical, and mechanical properties as well as in vitro degradation behavior of scaffolds were investigated. The mean diameters of nanofibers were 974 ± 68 nm for the pure PLGA scaffolds vs 832 ± 70, 764 ± 80, and 486 ± 64 for the PLGA/gelatin, PLGA/10 wt% MSNPs, and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The results suggested that the incorporation of gelatin and MSNPs into PLGA-based scaffolds enhances the hydrophilicity of scaffolds due to an increase of hydrophilic functional groups on the surface of nanofibers. With porosity examination, it was concluded that the incorporation of MSNPs and gelatin decrease the porosity of scaffolds. Nanoparticles also improved the tensile mechanical properties of scaffolds. Using in vitro degradation analysis, it was shown that the addition of nanoparticles to the nanofibers matrix increases the weight loss percentage of PLGA-based samples, whereas it decreases the weight loss percentage in the PLGA/gelatin composites. Cultivation of rat pheochromocytoma cell line (PC12), as precursor cells of dopaminergic neural cells, on the scaffolds demonstrated that the introduction of MSNPs into PLGA and PLGA/gelatin matrix leads to improved cell attachment and proliferation and enhances cellular processes. - Highlights: • PLGA-based random nanofibers embedded with mesoporous silica nanoparticles were fabricated using electrospinning method • Incorporation of gelatin and MSNPs into PLGA-based scaffolds increased the hydrophilicity of scaffold • Addition of nanoparticles also improved the tensile mechanical properties of scaffolds • Introduction of MSNPs led to improved cell attachment and proliferation.

Studies on electronic structure of interfaces between Ag and gelatin for stabilization of Ag nanoparticles

International Nuclear Information System (INIS)

Tani, Tadaaki; Uchida, Takayuki

2015-01-01

Extremely high stability of Ag nanoparticles in photographic materials has forced us to study the electronic structures of the interfaces between thin layers of Ag, Au, and Pt and their surface membranes in ambient atmosphere by photoelectron yield spectroscopy in air and Kelvin probe method. Owing to the Fermi level equalization between a metal layer and a membrane coming from air, the electron transfer took place from the membrane to Pt and Au layers and from an Ag layer to the membrane, giving the reason for poor stability of Ag nanoparticles in air. The control of the Fermi level of an Ag layer with respect to that of a gelatin membrane in air could be widely made according to Nernst's equation by changing the pH and pAg values of an aqueous gelatin solution used to form the membrane, and thus available to stabilize Ag nanoparticles in a gelatin matrix. (author)

Halloysite nanotube supported Ag nanoparticles heteroarchitectures as catalysts for polymerization of alkylsilanes to superhydrophobic silanol/siloxane composite microspheres.

Science.gov (United States)

Li, Cuiping; Li, Xueyuan; Duan, Xuelan; Li, Guangjie; Wang, Jiaqiang

2014-12-15

Halloysite nanotube supported Ag nanoparticles heteroarchitectures have been prepared through a very simple electroless plating method. Robust Ag nanocrystals can be reproducibly fabricated by soaking halloysite nanotubes in ethanolic solutions of AgNO3 and butylamine. By simply adjusting the molar ratio of AgNO3 and butylamine, Ag nanoparticles with tunable size and quantity on halloysite nanotube are achieved. It reveals that the Ag nanoparticles are well-dispersed on the surface of halloysite nanotubes. The halloysite nanotube supported Ag nanoparticles heteroarchitectures can serve as active catalysts for the polymerization of an alkylsilane C18H37SiH3 with water to form silanol/siloxane composite microspheres and exhibit interesting superhydrophobicity ascribed to the micro/nanobinary structure. Copyright © 2014 Elsevier Inc. All rights reserved.

Prominent ethanol sensing with Cr2O3 nanoparticle-decorated ZnS nanorods sensors

Science.gov (United States)

Sun, Gun-Joo; Kheel, Hyejoon; Ko, Tae-Gyung; Lee, Chongmu; Kim, Hyoun Woo

2016-08-01

ZnS nanorods and Cr2O3 nanoparticle-decorated ZnS nanorods were synthesized by using facile hydrothermal techniques, and their ethanol sensing properties were examined. X-ray diffraction and scanning electron microscopy revealed good crystallinity and size uniformity for the ZnS nanorods. The Cr2O3 nanoparticle-decorated ZnS nanorod sensor showed a stronger response to ethanol than the pristine ZnS nanorod sensor. The responses of the pristine and the decorated nanorod sensors to 200 ppm of ethanol at 300 °C were 2.9 and 13.8, respectively. Furthermore, under these conditions, the decorated nanorod sensor showed a longer response time (23 s) and a shorter recovery time (20 s) than the pristine one did (19 and 35 s, respectively). Consequently, the total sensing time of the decorated nanorod sensor (42 s) was shorter than that of the pristine one (55 s). The decorated nanorod sensor showed excellent selectivity to ethanol over other volatile organic compound gases including acetone, methanol, benzene, and toluene whereas the pristine one failed to show selectivity to ethanol over acetone. The improved sensing performance of the decorated nanorod sensor is attributed to a modulation of the width of the conduction channel and the height of the potential barrier at the ZnS-Cr2O3 interface accompanying the adsorption and the desorption of ethanol gas, and the greater surface-to-volume ratio of the decorated nanorods which was greater than that of the pristine one due to the existence of the ZnS-Cr2O3 interface.

Influence of metal nanoparticle decorated CNTs on polyurethane based electro active shape memory nanocomposite actuators

International Nuclear Information System (INIS)

Raja, Mohan; Shanmugharaj, A.M.; Ryu, Sung Hun; Subha, J.

2011-01-01

Highlights: → Polyurethane based on pristine and metal (Ag and Cu) nanoparticle decorated CNTs nanocomposites are prepared through melt blending process. → The electrical, mechanical, dynamic mechanical, thermal conductivity and electro active shape memory properties of the PU nanocomposites were investigated. → The influence of metal nanoparticle decorated CNTs showed significant improvement in their all properties to compare to pristine CNTs. → Electro active shape memory studies of the PU/M-CNTs nanocomposites reveal extraordinary recoverability of its shape at lower applied dc voltages. - Abstract: Polymer nanocomposites based on thermoplastic polyurethane (PU) elastomer and metal nanoparticle (Ag and Cu) decorated multiwall carbon nanotubes (M-CNTs) were prepared through melt mixing process and investigated for its mechanical, dynamic mechanical and electro active shape memory properties. Structural characterization and morphological characterization of the PU nanocomposites were done using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Morphological characterization revealed better dispersion of M-CNTs in the polyurethane, which is attributed to the improved interaction between the M-CNTs and polyurethane. Loading of the metal nanoparticle coated carbon nanotubes resulted in the significant improvement on the mechanical properties such as tensile strength of the PU composites in comparison to the pristine carbon nanotubes (P-CNTs). Dynamic mechanical analysis showed that the glass transition temperature (Tg) of the polyurethane increases slightly with increasing loading of both pristine and metal nanoparticle functionalized carbon nanotubes. The metal nanoparticles decorated carbon nanotubes also showed significant improvement in the thermal and electrical conductivity of the PU/M-CNTs nanocomposites. Shape memory studies of the PU/M-CNTs nanocomposites exhibit remarkable recoverability of its shape at lower applied dc voltages.

Radius ratio rule for surface hydrophilization of polydimethyl siloxane and silica nanoparticle composite

Energy Technology Data Exchange (ETDEWEB)

Toutam, Vijaykumar, E-mail: toutamvk@nplindia.org [Quantum Phenomena and Applications Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Jain, Puneet; Sharma, Rina [Quantum Phenomena and Applications Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Bathula, Sivaiah; Dhar, Ajay [Material Physics and Engineering Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India)

2015-09-15

Graphical abstract: - Highlights: • Binary hard sphere silica nanoparticle system based PDMS composite. • Enhanced hydrophilization and retainability of the composite. • Restriction of uncured PDMS from diffusion. • Increased Debye length of electrostatic double layer, measured by F-D Spectroscopy. - Abstract: Polydimethyl siloxane (PDMS) and Silica (SiO{sub 2}) nanoparticle composite blocks of three different batches (CB1–CB3) made by varying the size of SiO{sub 2} nanoparticles (NP), are studied for the degree of hydrophilization and retainability after oxidation by contact angle measurements (CA) and force distance spectroscopy (FDS) using Atomic Force Microscope (AFM). While CA measurements have shown high hydrophilization and retainability for CB3, F-D spectroscopy has reiterated the observation and has shown long range interactive forces and high Debye length of the electrostatic double layer formed. These results are in agreement with the radius ratio rule of binary sphere system for high density packing in the composite and thereby for strong hydrophilization and retainability due to reinforcement and restricted diffusion of uncured polymer.

Fe3O4 nanoparticles decorated MWCNTs @ C ferrite nanocomposites and their enhanced microwave absorption properties

Science.gov (United States)

Zhang, Kaichuang; Gao, Xinbao; Zhang, Qian; Chen, Hao; Chen, Xuefang

2018-04-01

Fe3O4 nanoparticles decorated MWCNTs @ C ferrite nanocomposites were synthesized using a co-precipitation method and a calcination process. As one kind absorbing material, we researched the electromagnetic absorption properties of the composites that were mixed with a filler loading of 80 wt% paraffin. In addition, we studied the influence of the magnetic nanoparticle content on the absorbing properties. The results showed that the frequency corresponding to the maximum absorptions shifted to lower frequency when the magnetic nanoparticles content increased. The Fe3O4 nanoparticles decorated MWCNTs @ C ferrite nanocomposites with approximately 60% Fe3O4 nanoparticles showed the best electromagnetic absorption properties. The maximum reflection loss was -52.47 dB with a thickness of 2.0 mm at 10.4 GHz.

Gelatin coated hybrid lipid nanoparticles for oral delivery of amphotericin B

DEFF Research Database (Denmark)

Jain, Sanyog; Valvi, Pankaj U; Swarnakar, Nitin K

2012-01-01

Amphotericin B (AmB) loaded polymer lipid hybrid nanoparticles (AmB-PLNs) comprised of lecithin (anionic lipid) and gelatin (Type A, cationic below its isoelectric point 7.0-9.0) were prepared by a two-step desolvation method to improve the oral bioavailability of AmB. The optimized AmB-PLNs were......) and fluorescent resonance energy transfer (FRET) analysis confirmed the orientation of the lecithin (located in the core) and gelatin (exterior coat) within the system. The developed formulation exhibited a sustained drug release profile with a release pattern best fitted to Higuchi kinetics. Experiments on Caco...

D-Glucose as a modifying agent in gelatin/collagen matrix and reservoir nanoparticles for Calendula officinalis delivery.

Science.gov (United States)

Lam, P-L; Kok, S H-L; Bian, Z-X; Lam, K-H; Tang, J C-O; Lee, K K-H; Gambari, R; Chui, C-H

2014-05-01

Gelatin/Collagen-based matrix and reservoir nanoparticles require crosslinkers to stabilize the formed nanosuspensions, considering that physical instability is the main challenge of nanoparticulate systems. The use of crosslinkers improves the physical integrity of nanoformulations under the-host environment. Aldehyde-based fixatives, such as formaldehyde and glutaraldehyde, have been widely applied to the crosslinking process of polymeric nanoparticles. However, their potential toxicity towards human beings has been demonstrated in many previous studies. In order to tackle this problem, D-glucose was used during nanoparticle formation to stabilize the gelatin/collagen-based matrix wall and reservoir wall for the deliveries of Calendula officinalis powder and oil, respectively. In addition, therapeutic selectivity between malignant and normal cells could be observed. The C. officinalis powder loaded nanoparticles significantly strengthened the anti-cancer effect towards human breast adenocarcinoma MCF7 cells and human hepatoma SKHep1 cells when compared with the free powder. On the contrary, the nanoparticles did not show significant cytotoxicity towards normal esophageal epithelial NE3 cells and human skin keratinocyte HaCaT cells. On the basis of these evidences, D-glucose modified gelatin/collagen matrix nanoparticles containing C. officinalis powder might be proposed as a safer alternative vehicle for anti-cancer treatments. Copyright © 2014 Elsevier B.V. All rights reserved.

Cutaneous biocompatible rutin-loaded gelatin-based nanoparticles increase the SPF of the association of UVA and UVB filters.

Science.gov (United States)

Oliveira, Camila Areias de; Peres, Daniela D'Almeida; Graziola, Fabiana; Chacra, Nádia Araci Bou; Araújo, Gabriel Lima Barros de; Flórido, Ana Catarina; Mota, Joana; Rosado, Catarina; Velasco, Maria Valéria Robles; Rodrigues, Luís Monteiro; Fernandes, Ana Sofia; Baby, André Rolim

2016-01-01

The encapsulation of natural ingredients, such as rutin, can offer improvements in sun protection effectiveness. This strategy can provide enhanced flavonoid content and produces an improved bioactive compound with new physical and functional characteristics. As an alternative to common synthetic-based sunscreens, rutin-entrapped gelatin nanoparticles (GNPs) were designed and associated with ethylhexyl dimethyl PABA (EHDP), ethylhexyl methoxycinnamate (EHMC) and methoxydibenzoylmethane (BMDBM) in sunscreen formulations. The purpose of this study was to develop rutin-loaded gelatin nanoparticles and characterize their physicochemical, thermal, functional and safety properties. Rutin-loaded gelatin nanoparticles increased antioxidant activity by 74% relative to free-rutin (FR) solution. Also, this new ingredient upgraded the Sun Protection Factor (SPF) by 48%, indicating its potential as a raw material for bioactive sunscreens. The safety profile indicated that GNPs and glutaraldehyde (GTA) decreased HaCaT cell viability in a concentration/time-dependent manner. However, both blank nanoparticles (B-NC) and rutin-loaded nanoparticles (R-NC) had good performance on skin compatibility tests. These results functionally characterized rutin-loaded nanoparticles as a safe SPF enhancer in sunscreens, especially in association with UV filters. Copyright © 2015 Elsevier B.V. All rights reserved.

Gelatin modified lipid nanoparticles for anti- viral drug delivery.

Science.gov (United States)

K S, Joshy; S, Snigdha; Kalarikkal, Nandakumar; Pothen, Laly A; Thomas, Sabu

2017-10-01

The major challenges to clinical application of zidovudine are its moderate aqueous solubility and relative short half-life and serious side effects due to frequent administrations. We investigated the preparation of zidovudine-loaded nanoparticles based on lipids which were further modified with the polymer gelatin. Formulation and stability of the modified nanoparticles were analysed from the physico-chemical characterizations. The interactions of nanoparticles with blood components were tested by haemolysis and aggregation studies. The drug content and entrapment efficiencies were assessed by UV analysis. The effect of nanoparticles on protein adsorption was assessed by native polyacrylamide gel electrophoresis (PAGE). In vitro release studies showed a sustained release profile of zidovudine. In vitro cytotoxicity and cellular uptake of the zidovudine-loaded nanoparticles were performed in MCF-7 and neuro 2a brain cells. The enhanced cellular internalization of drug loaded modified nanoparticles in both the cell lines were revealed by fluorescence microscopy. Hence the present study focuses on the feasibility of zidovudine-loaded polymer modified lipid nanoparticles as carriers for safe and efficient HIV/AIDS therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and characterization of folate decorated albumin bio-conjugate nanoparticles loaded with a synthetic curcumin difluorinated analogue.

Science.gov (United States)

Gawde, Kaustubh A; Kesharwani, Prashant; Sau, Samaresh; Sarkar, Fazlul H; Padhye, Subhash; Kashaw, Sushil K; Iyer, Arun K

2017-06-15

Albumin-bound paclitaxel colloidal nanoparticle (Abraxane®) is an FDA approved anticancer formulation available in the market. It is a suspension which is currently used therapeutically for treating cancers of the breast, lung, and pancreas among others. CDF is a novel new and potent synthetic curcumin analogue that is widely used for breast and ovarian cancer. The aim of this study was to use biocompatible albumin as well as folate decorated albumin to formulate colloidal nanoparticles encapsulating curcumin difluorinated (CDF). CDF has demonstrated a 16-fold improvement in stability and remarkable anticancer potency compared to its natural derivative, curcumin. CDF showed marked inhibition of cancer cell growth through down-regulation of multiple miRNAs, up-regulation of phosphatase and tensin homolog (PTEN), and attenuation of histone methyl transferase EZH2. However, CDF is highly hydrophobic and photodegradable with sparing aqueous solubility. In this study, we have formulated albumin nanoparticle using a modified desolvation method, which yielded high CDF loading in a nanoformulation. The physicochemical properties of CDF loaded albumin and folate-decorated albumin nanosuspensions were assessed for particle size, morphology, zeta potential, drug encapsulation efficiency/loading, solubility and drug release. Importantly, the folate ligand decorated albumin nanoparticles were formulated in principle to passively and actively target folate-overexpressing-cancers. In this study, the synthesis and optimization of BSA and folate decorated BSA conjugated CDF nanoparticles are assessed in detail that will be useful for its future clinical translation. Copyright © 2017 Elsevier Inc. All rights reserved.

Size-dependent internalisation of folate-decorated nanoparticles via the pathways of clathrin and caveolae-mediated endocytosis in ARPE-19 cells.

Science.gov (United States)

Langston Suen, Wai-Leung; Chau, Ying

2014-04-01

We aim to quantify the effect of size and degree of folate loading of folate-decorated polymeric nanoparticles (NPs) on the kinetics of cellular uptake and the selection of endocytic pathways in retinal pigment epithelium (RPE) cells. In this study, methoxy-poly(ethylene glycol)-b-polycaprolactone (mPEG-b-PCL) and folate-functionalized PEG-b-PCL were synthesized for assembling into nanoparticles with sizes ranging from 50 nm to 250 nm. These nanoparticles were internalized into ARPE-19 (human RPE cell line) via receptor-mediated endocytosis. A two-step endocytosis process mathematical model was adopted to quantify binding affinity and uptake kinetics of nanoparticles in RPE cells in uptake and inhibition studies. Nanoparticles with 100% folate loading have highest binding affinity and uptake rate in RPE cells. Maximum uptake rate (Vmax) of nanoparticles increased as the size of particles decreased from 250 nm to 50 nm. Endocytic pathway study was studied by using chlorpromazine and methyl-β-cyclodextran (MβCD), which are clathrin- and caveolae-mediated endocytosis inhibitors, respectively. Both chlorpromazine and MβCD inhibited the uptake of folate-decorated nanoparticles. Inhibition constant (Ki) and maximum uptake rate (Vmax) revealed that 50 nm and 120 nm folate-decorated nanoparticles were found to be internalized via both clathrin- and caveolae-mediated endocytosis. The 250 nm folate-decorated nanoparticles, however, were only internalized via caveolae-mediated pathway. Increased uptake rate of folate-decorated NPs into RPE cells is observed with increasing degree of folate modification. These NPs utilize both clathrin- and caveolae-mediated receptor-mediated endocytosis pathways to enter RPE cells upon size variation. The 50 nm NPs are internalized the fastest, with clathrin-mediated endocytosis as the preferred route. Uptake of 250 nm particles is the slowest and is dominated by caveolae-mediated endocytosis. © 2013 Royal Pharmaceutical

Preparation of gelatin films incorporated with tea polyphenol nanoparticles for enhancing controlled-release antioxidant properties.

Science.gov (United States)

Liu, Fei; Antoniou, John; Li, Yue; Yi, Jiang; Yokoyama, Wallace; Ma, Jianguo; Zhong, Fang

2015-04-22

Gelatin films incorporated with chitosan nanoparticles in various free/encapsulated tea polyphenol (TP) ratios were prepared in order to investigate the influence of different ratios on the physicochemical and antioxidant properties of films. The TP-containing nanoparticles were prepared by cross-linking chitosan hydrochloride (CSH) with sulfobutyl ether-β-cyclodextrin sodium (SBE-β-CD) at three different encapsulation efficiencies (EE; ∼50%, ∼80%, and ∼100%) of TP. The stability of TP-loaded nanoparticles was maintained during the film drying process from the analysis of free TP content in the redissolved film solutions. Composite films showed no significant difference in visual aspects, while the light transmittance (250-550 nm) was decreased with incorporation of TP. Nanoparticles appeared to be homogeneously dispersed within the film matrix by microstructure analysis (SEM and AFM). TP-loaded films had ferric reducing and DPPH radical scavenging power that corresponded to the EEs. Sunflower oil packaged in bags made of gelatin films embedded with nanoparticles of 80% EE showed the best oxidation inhibitory effect, followed by 100% EE, 50% EE, and free TP, over 6 weeks of storage. However, when the gelatin film was placed over the headspace and was not in contact with the oil, the free TP showed the best effect. The results indicate that sustained release of TP in the contacting surface can ensure the protective effects, which vary with free/encapsulated mass ratios, thus improving antioxidant activities instead of increasing the dosage.

Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

Directory of Open Access Journals (Sweden)

Rudolf Herrmann

2014-12-01

Full Text Available The present review article covers work done in the cluster NPBIOMEM in the DFG priority programme SPP 1313 and focuses on synthesis and characterization of fluorescent silica and ceria nanoparticles. Synthetic methods for labelling of silica and polyorganosiloxane/silica core–shell nanoparticles with perylenediimide derivatives are described, as well as the modification of the shell with thiol groups. Photometric methods for the determination of the number of thiol groups and an estimate for the number of fluorescent molecules per nanoparticles, including a scattering correction, have been developed. Ceria nanoparticles decorated with noble metals (Pt, Pd, Rh are models for the decomposition products of automobile catalytic converters which appear in the exhaust gases and finally interact with biological systems including humans. The control of the degree of agglomeration of small ceria nanoparticles is the basis for their synthesis. Almost monodisperse agglomerates (40 ± 4–260 ± 40 nm diameter can be prepared and decorated with noble metal nanoparticles (2–5 nm diameter. Fluorescence labelling with ATTO 647N gave the model particles which are now under biophysical investigation.

Antimicrobial activity of tantalum oxide coatings decorated with Ag nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Cao, Huiliang, E-mail: hlc@mail.sic.ac.cn; Meng, Fanhao; Liu, Xuanyong, E-mail: xyliu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2016-07-15

Silver plasma immersion ion implantation was used to decorate silver nanoparticles (Ag NPs) on tantalum oxide (TO) coatings. The coatings acted against bacterial cells (Staphylococcus epidermidis) in the dark by disrupting their integrity. The action was independent of silver release and likely driven by the electron storage capability of the Schottky barriers established at the interfaces between Ag NPs and the TO support. Moreover, no apparent side effect on the adhesion and differentiation of rat bone mesenchymal stem cells was detected when using Ag NPs-modified TO coatings. These results demonstrate that decoration of tantalum oxide using Ag NPs could be a promising procedure for improving the antibacterial properties for orthopedic and dental implants.

In situ synthesis of carbon nanotubes decorated with palladium nanoparticles using arc-discharge in solution method

International Nuclear Information System (INIS)

Bera, Debasis; Kuiry, Suresh C.; McCutchen, Matthew; Seal, Sudipta; Heinrich, Helge; Slane, Grady C.

2004-01-01

A unique, simple, inexpensive, and one-step synthesis route to produce carbon nanotubes (CNTs) decorated with palladium nanoparticles using a simplified dc arc-discharge in solution is reported. Zero-loss energy filtered transmission electron microscopy and scanning transmission electron microscopy confirm the presence of 3 nm palladium nanoparticles. Such palladium nanoparticles form during the reduction of palladium tetra-chloro-square-planar complex. The deconvoluted x-ray photoelectron spectroscopy envelope shows the presence of palladium on the decorated CNTs. The energy dispersive spectroscopy suggests no functionalization of atomic chlorine to the sidewall of the CNTs. The presence of dislodged graphene sheets with wavy morphology supports the formation of CNTs through the 'scroll mechanism'

The role of surface charge in the desolvation process of gelatin: implications in nanoparticle synthesis and modulation of drug release

Directory of Open Access Journals (Sweden)

Ahsan SM

2017-01-01

Full Text Available Saad M Ahsan, Chintalagiri Mohan Rao Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, Telangana, India Abstract: The process of moving hydrophobic amino acids into the core of a protein by desolvation is important in protein folding. However, a rapid and forced desolvation can lead to precipitation of proteins. Desolvation of proteins under controlled conditions generates nanoparticles – homogeneous aggregates with a narrow size distribution. The protein nanoparticles, under physiological conditions, undergo surface erosion due to the action of proteases, releasing the entrapped drug/gene. The packing density of protein nanoparticles significantly influences the release kinetics. We have investigated the desolvation process of gelatin, exploring the role of pH and desolvating agent in nanoparticle synthesis. Our results show that the desolvation process, initiated by the addition of acetone, follows distinct pathways for gelatin incubated at different pH values and results in the generation of nanoparticles with varying matrix densities. The nanoparticles synthesized with varying matrix densities show variations in drug loading and protease-dependent extra- and intracellular drug release. These results will be useful in fine-tuning the synthesis of nanoparticles with desirable drug release profiles. Keywords: protein desolvation, nanoparticle assembly, gelatin nanoparticle synthesis, protease susceptibility, intracellular drug release

Incorporation of mesoporous silica nanoparticles into random electrospun PLGA and PLGA/gelatin nanofibrous scaffolds enhances mechanical and cell proliferation properties

DEFF Research Database (Denmark)

Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Nasri-Nasrabadi, Bijan

2016-01-01

Poly(lactic-co-glycolic.acid) (PLGA) and PLGA/gelatin random nanofibrous scaffolds embedded with different amounts of mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. To evaluate the effects of nanoparticles on the scaffolds, physical, chemical, and mechanical...... the porosity of scaffolds. Nanoparticles also improved the tensile mechanical properties of scaffolds. Using in vitro degradation analysis, it was shown that the addition of nanoparticles to the nano fibers matrix increases the weight loss percentage of PLGA-based samples, whereas it decreases the weight loss...... properties as well as in vitro degradation behavior of scaffolds were investigated. The mean diameters of nanofibers were 974 ± 68 nm for the pure PLGA scaffolds vs 832 ± 70, 764 ± 80, and 486 ± 64 for the PLGA/gelatin, PLGA/10 wt% MSNPs, and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The results...

V-groove SnO2 nanowire sensors: fabrication and Pt-nanoparticle decoration

International Nuclear Information System (INIS)

Sun, Gun-Joo; Choi, Sun-Woo; Jung, Sung-Hyun; Katoch, Akash; Kim, Sang Sub

2013-01-01

Networked SnO 2 nanowire sensors were achieved using the selective growth of SnO 2 nanowires and their tangling ability, particularly on on-chip V-groove structures, in an effort to overcome the disadvantages imposed on the conventional trench-structured SnO 2 nanowire sensors. The sensing performance of the V-groove-structured SnO 2 nanowire sensors was highly dependent on the geometrical dimension of the groove, being superior to those of their conventional trench-structured counterparts. Pt nanoparticles were decorated on the surface of the networked SnO 2 nanowires via γ-ray radiolysis to enhance the sensing performances of the V-groove sensors whose V-groove widths had been optimized. The V-groove-structured Pt-nanoparticle-decorated SnO 2 nanowire sensors exhibited outstanding and reliable sensing capabilities towards toluene and nitrogen dioxide gases, indicating their potential for use as a platform for chemical gas sensors. (paper)

Synthesis and characterization of rod-like ZnO decorated with γ-Fe{sub 2}O{sub 3} nanoparticles monolayer

Energy Technology Data Exchange (ETDEWEB)

Balti, Imen, E-mail: imenbalti12@yahoo.fr [Unité de Recherche 99/UR12-30, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna (Tunisia); Laboratoire des Sciences des Procédés et Matériaux, LSPM, CNRS, UPR 3407, Université Paris XIII, 99 Avenue J.B. Clément, 93430 Villetaneuse (France); Smiri, Laila Samia [Unité de Recherche 99/UR12-30, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna (Tunisia); Rabu, Pierre [Département de Chimie des Matériaux Inorganiques, IPCMS, UMR 7504, CNRS–UDS, 23, rue du Loess, BP 43, Strasbourg Cedex 2 (France); Gautron, Eric [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Viana, Bruno [LCMCP, Chimie-Paristech, UPMC, Collège de France, UMR CNRS 7574, 11 rue Pierre et Marie Curie, 75005 Paris (France); Jouini, Noureddine [Laboratoire des Sciences des Procédés et Matériaux, LSPM, CNRS, UPR 3407, Université Paris XIII, 99 Avenue J.B. Clément, 93430 Villetaneuse (France)

2014-02-15

Highlights: ► Rod-like ZnO decorated with γ-Fe{sub 2}O{sub 3} nanoparticles have been prepared using forced hydrolysis in polyol medium. ► The system presents excellent UV photoluminescence properties along with superparamagnetic behavior. -- Abstract: Decorated rod-like ZnO particles with γ-Fe{sub 2}O{sub 3} nanoparticles monolayer (ZnO@γ-Fe{sub 2}O{sub 3}) were prepared via a simple route using forced hydrolysis of metal acetates in a polyol medium. The phases and purity of the as-prepared particles were established by powder X-ray diffraction (PXRD) and X-ray photo-electron spectroscopy (XPS) analyses. Transmission electron microscopy (TEM) showed that the ZnO particles present a typical rod-like morphology with ∼80 nm diameter and ∼200–400 nm length. These nanorods are decorated with well-organized γ-Fe{sub 2}O{sub 3} spherical nanoparticles showing a narrow size distribution around 5 nm. The photoluminescence (PL) spectra of the bare ZnO particles show predominant UV-excitonic and weak visible emission. The latter vanishes after covering the surface with the γ-Fe{sub 2}O{sub 3} nanoparticles suggesting an effect on the oxygen stoichiometry at the surface of the ZnO nanorods. The decorated nanoparticles exhibit magnetic response to an external magnetic field at room temperature and a superparamagnetic character with very low blocking temperature likely related to the organisation of γ-Fe{sub 2}O{sub 3} nanoparticles as monolayer.

Supercapacitor electrode of nano-Co3O4 decorated with gold nanoparticles via in-situ reduction method

Science.gov (United States)

Tan, Yongtao; Liu, Ying; Kong, Lingbin; Kang, Long; Ran, Fen

2017-09-01

Nano-Co3O4 decorated with gold nanoparticles is synthesized by a simple method of in-situ reduction of HAuCl4 by sodium citrate for energy storage application, and the effect of gold content in the product on electrochemical performance is investigated in detail. Introducing gold nanoparticles into nano-Co3O4 bulk would contribute to reduce internal resistance of charge transmission. The results show that after in-situ reduction reaction gold nanoparticles imbed uniformly into nano-Co3O4 with irregular nanoparticles. The gold nanoparticles decorated nano-Co3O4 exhibits specific capacitance of 681 F g-1 higher than that of pristine Co3O4 of 368 F g-1. It is interesting that a good cycle life with the specific capacitance retention of 83.1% is obtained after 13000 cycles at 5 A g-1, which recovers to initial specific capacitance value when the test current density is turned to 2 A g-1. In addition, the device of asymmetric supercapacitor, assembled with gold nanoparticles decorated nano-Co3O4 as the positive electrode and activated carbon as the negative electrode, exhibits good energy density of 25 Wh kg-1, which is comparable to the asymmetric device assembled with normal nano-Co3O4, or the symmetric device assembled just with activated carbon.

Synthesis of Nickel Oxide Nanoparticles Using Gelatine as a Green Template for Photocatalytic Degradation of Dye

OpenAIRE

JAY YANG LEE

2018-01-01

Nickel oxide (NiO) nanoparticles were synthesized through sol-gel method with an environmentally friendly templating agent, which is gelatin. The synthesized NiO were characterized to determine the chemical and physical properties of the nanoparticles. The optimum synthesis parameters were used in photocatalytic degradation of Reactive Black 5 and Acid Yellow 25 dye to determine the catalytic activity of the nanoparticles.

Effect of silver nanoparticles on the spectral luminescent properties of a gelatin film

Science.gov (United States)

Efendiev, T. Sh.; Kruchenok, J. V.; Rubinov, A. N.

2013-03-01

We studied the absorption and fluorescence spectra of a rhodamine 6G-activated gelatin film of thickness 10 μm, with and without silver nanoparticles. We observed that doping the film with nanoparticles of diameter 5 nm leads to an increase in the intensity of the absorption spectrum by a factor of 1.17 and its short-wavelength shift (~1.5 nm), while the intensity of the fluorescence spectrum increases by a factor of ~2.

Graphene oxide chemically decorated with hybrid Ag-Ru/chitosan nanoparticles: fabrication and properties

OpenAIRE

Veerapandian, Murugan; Neethirajan, Suresh

2015-01-01

Hybridization of distinct materials into a single nanoplatform is relevant to advance material’s properties for functional application such as biosensor platform. We report the synthesis and characterization of nanosheets of graphene oxide decorated with hybrid nanoparticles of silver-ruthenium bipyridine complex (Ag@[Ru(bpy)3]2+) core and chitosan shell. Hybrid nanoparticles were first obtained through a sequential wet-chemical approach using in situ reduction, electrostatic and coordination...

Carboxymethylated ɩ-carrageenan conjugated amphotericin B loaded gelatin nanoparticles for treating intracellular Candida glabrata infections.

Science.gov (United States)

Aparna, V; Melge, Anu Rohit; Rajan, V K; Biswas, Raja; Jayakumar, R; Gopi Mohan, C

2018-04-15

Intercellular Candida glabrata infections are difficult to treat due to poor penetration of drugs into the fungal niche. Delivering amphotericin B (Amp B) into the macrophages where the pathogen inhabits is an effective solution. We are studying the macrophage targeting proficiency of ɩ-carrageenan for the delivery of Amp B using gelatin A nanoparticles (GNPs). The choice of gelatin A was the outcome of in silico inspections where the amino functionalized polymer having the best docking score with Amp B was selected. We prepared a sustained release formulation of amp B loaded carboxymethyl ɩ-carrageenan conjugated gelatin nanoparticles (CMC-Amp B-GNPs) with size 343±12nm and -25±5.3mV zeta potential. The formulations were found to be stable, biocompatible and non-haemolytic. Flow cytometry analysis showed 3 fold higher uptake of CMC-GNPs compared to the GNPs by RAW 264.7 cells. CMC-Amp B-GNPs showed enhanced antifungal activity than bare Amp B and Amp B-GNPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and characterization of copper oxide nanoparticles decorated carbon nanoparticles using laser ablation in liquid

Science.gov (United States)

Khashan, K. S.; Jabir, M. S.; Abdulameer, F. A.

2018-05-01

Carbon nanoparticles CNPs ecorated by copper oxide nano-sized particles would be successfully equipped using technique named pulsed laser ablation in liquid. The XRD pattern proved the presence of phases assigned to carbon and different phases of copper oxide. The chemical structure of the as-prepared nanoparticles samples was decided by Energy Dispersive Spectrum (EDS) measurement. EDS analysis results show the contents of Carbon, Oxygen and Copper in the final product. These nanoparticles were spherical shaped with a size distribution 10 to 80 nm or carbon nanoparticles and 5 to 50 nm for carbon decorated copper oxide nanoparticles, according to Transmission Electron Microscopy (TEM) images and particle-size distribution histogram. It was found that after doping with copper oxide, nanoparticles become smaller and more regular in shape. Optical absorption spectra of prepared nanoparticles were measured using UV–VIS spectroscopy. The absorption spectrum of carbon nanoparticles without doping indicates absorption peak at about 228 nm. After doping with copper oxide, absorption shows appearance of new absorption peak at about (254-264) nm, which is referred to the movement of the charge between 2p and 4s band of Cu2+ ions.

Effect of silver nanoparticles on the spectral luminescent properties of a gelatin film

International Nuclear Information System (INIS)

Ehfendiev, T.Sh.; Kruchenok, Yu.V.; Rubinov, A.N.

2013-01-01

We studied the absorption and fluorescence spectra of a rhodamine 6G-activated gelatin film of thickness 10 μm, with and without silver nanoparticles.We observed that doping the film with nanoparticles of diameter 5 nm leads to an increase in the intensity of the absorption spectrum by a factor of 1.17 and its short-wavelength shift (~1.5 nm), while the intensity of the fluorescence spectrum increases by a factor of ~2. (author)

Preparation and characterization of gelatin mediated silver nanoparticles by laser ablation

International Nuclear Information System (INIS)

Darroudi, Majid; Ahmad, Mansor B.; Zamiri, Reza; Abdullah, Abdul Halim; Ibrahim, Nor Azowa; Shameli, Kamyar; Shahril Husin, M.

2011-01-01

Research highlights: → To date, no approach has been carried out on the preparation of Ag-NPs using gelatin as a stabilizer in the PLA method. → In this paper, we used the PLA method to focus on the preparation of Ag-NPs from silver plating in water using gelatin as a stabilizer. → The effect of the laser-pulsed repetition rate on size of Ag-NPs is studied. - Abstract: We successfully prepared colloidal silver nanoparticles (Ag-NPs) using a nanosecond pulsed Nd:YAG laser, λ = 532 nm, with laser fluence of approximately about 0.6 J/pulse, in an aqueous gelatin solution. The size and optical absorption properties of samples were studied as a function of the laser repetition rates. The results from the UV-vis spectroscopy demonstrated that the mean diameter of Ag-NPs increase with the laser repetition rate increases. The Ag-NPs have mean diameters ranging from approximately 9 nm to 15 nm. Compared with other preparation methods, this work is clean, rapid, and simple to use.

Silver Nanoparticles Synthesized Using Mint Extract and their Application in Chitosan/Gelatin Composite Packaging Film

Science.gov (United States)

Bhoir, Shraddha A.; Chawla, S. P.

The present study reports synthesis of silver nanoparticles (AgNPs) using mint extract (ME) in the presence of polyvinyl alcohol (PVA) as capping material. PVA, ME and silver nitrate at concentration of 1%, 0.01% and 0.02%, respectively were found to be optimum for the synthesis of nanoparticles. The formation of AgNPs was confirmed by measuring surface plasmon resonance (SPR) peak. The intensity of SPR peak remained unaltered thus suggesting stability of colloid without aggregation during storage. The nanoparticles inhibited the growth of food borne bacteria namely Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus. The incorporation of these nanoparticles in chitosan and gelatin blend resulted in homogenous films. Mechanical properties and water vapor transmission rate of chitosan-gelatin films improved due to addition of AgNPs, whereas optical (opacity and UV light transmittance) and oxygen permeability properties remained unchanged. These films had the ability to inhibit growth of 5 log CFU of the above test organisms. These findings suggest that the AgNPs obtained by reduction of silver by ME can be effectively utilized to prepare antibacterial eco-friendly food packaging material.

The antimicrobial effect of silicon nanowires decorated with silver and copper nanoparticles

International Nuclear Information System (INIS)

Fellahi, Ouarda; Marcon, Lionel; Coffinier, Yannick; Boukherroub, Rabah; Sarma, Rupak K; Saikia, Ratul; Das, Manash R; Hadjersi, Toufik; Maamache, Mustapha

2013-01-01

The paper reports on the preparation and antibacterial activity of silicon nanowire (SiNW) substrates coated with Ag or Cu nanoparticles (NPs) against Escherichia coli (E. coli) bacteria. The substrates are easily prepared using the metal-assisted chemical etching of crystalline silicon in hydrofluoric acid/silver nitrate (HF/AgNO 3 ) aqueous solution. Decoration of the SiNWs with metal NPs is achieved by simple immersion in HF aqueous solutions containing silver or copper salts. The SiNWs coated with Ag NPs are biocompatible with human lung adenocarcinoma epithelial cell line A549 while possessing strong antibacterial properties to E. coli. In contrast, the SiNWs decorated with Cu NPs showed higher cytotoxicity and slightly lower antibacterial activity. Moreover, it was also observed that leakage of sugars and proteins from the cell wall of E. coli in interaction with SiNWs decorated with Ag NPs is higher compared to SiNWs modified with Cu NPs. (paper)

Hydrogen peroxide sensor: Uniformly decorated silver nanoparticles on polypyrrole for wide detection range

International Nuclear Information System (INIS)

Nia, Pooria Moozarm; Meng, Woi Pei; Alias, Y.

2015-01-01

Graphical abstract: - Highlights: • Electrochemical method was used for depositing silver nanoparticles and polypyrrole. • Silver nanoparticles (25 nm) were uniformly decorated on electrodeposited polypyrrole. • (Ag(NH 3 ) 2 OH) precursor showed better electrochemical performance than (AgNO 3 ). • The sensor showed superior performance toward H 2 O 2 . - Abstract: Electrochemically synthesized polypyrrole (PPy) decorated with silver nanoparticles (AgNPs) was prepared and used as a nonenzymatic sensor for hydrogen peroxide (H 2 O 2 ) detection. Polypyrrole was fabricated through electrodeposition, while silver nanoparticles were deposited on polypyrrole by the same technique. The field emission scanning electron microscopy (FESEM) images showed that the electrodeposited AgNPs were aligned along the PPy uniformly and the mean particle size of AgNPs is around 25 nm. The electrocatalytic activity of AgNPs-PPy-GCE toward H 2 O 2 was studied using chronoamperometry and cyclic voltammetry. The first linear section was in the range of 0.1–5 mM with a limit of detection of 0.115 μmol l −1 and the second linear section was raised to 120 mM with a correlation factor of 0.256 μmol l −1 (S/N of 3). Moreover, the sensor presented excellent stability, selectivity, repeatability and reproducibility. These excellent performances make AgNPs-PPy/GCE an ideal nonenzymatic H 2 O 2 sensor.

Dislocation-induced nanoparticle decoration on a GaN nanowire.

Science.gov (United States)

Yang, Bing; Yuan, Fang; Liu, Qingyun; Huang, Nan; Qiu, Jianhang; Staedler, Thorsten; Liu, Baodan; Jiang, Xin

2015-02-04

GaN nanowires with homoepitaxial decorated GaN nanoparticles on their surface along the radial direction have been synthesized by means of a chemical vapor deposition method. The growth of GaN nanowires is catalyzed by Au particles via the vapor-liquid-solid (VLS) mechanism. Screw dislocations are generated along the radial direction of the nanowires under slight Zn doping. In contrast to the metal-catalyst-assisted VLS growth, GaN nanoparticles are found to prefer to nucleate and grow at these dislocation sites. High-resolution transmission electron microscopy (HRTEM) analysis demonstrates that the GaN nanoparticles possess two types of epitaxial orientation with respect to the corresponding GaN nanowire: (I) [1̅21̅0]np//[1̅21̅0]nw, (0001)np//(0001)nw; (II) [1̅21̅3]np//[12̅10]nw, (101̅0)np//(101̅0)nw. An increased Ga signal in the energy-dispersive spectroscopy (EDS) profile lines of the nanowires suggests GaN nanoparticle growth at the edge surface of the wires. All the crystallographic results confirm the importance of the dislocations with respect to the homoepitaxial growth of the GaN nanoparticles. Here, screw dislocations situated on the (0001) plane provide the self-step source to enable nucleation of the GaN nanoparticles.

Time-dependent preparation of gelatin-stabilized silver nanoparticles by pulsed Nd:YAG laser

Science.gov (United States)

Darroudi, Majid; Ahmad, M. B.; Zamiri, Reza; Abdullah, A. H.; Ibrahim, N. A.; Sadrolhosseini, A. R.

2011-03-01

Colloidal silver nanoparticles (Ag-NPs) were successfully prepared using a nanosecond pulsed Nd:YAG laser, λ = 1064 nm, with laser fluence of approximately about 360 mJ/pulse, in an aqueous gelatin solution. In this work, gelatin was used as a stabilizer, and the size and optical absorption properties of samples were studied as a function of the laser ablation times. The results from the UV-vis spectroscopy demonstrated that the mean diameter of Ag-NPs decrease as the laser ablation time increases. The Ag-NPs have mean diameters ranging from approximately 10 nm to 16 nm. Compared with other preparation methods, this work is clean, rapid, and simple to use.

STABILITY OF SYNTHESIZED SILVER NANOPARTICLES IN CITRATE AND MIXED GELATIN/CITRATE SOLUTION

Directory of Open Access Journals (Sweden)

Jana Kavuličová

2018-04-01

Full Text Available The study focuses on an investigation of the influence of both citrate and mixed gelatin/citrate as a reductant and stabilizer on the colloidal stability of silver nanoparticles (AgNPssynthesized by a chemical reduction of Ag+ ions after a short - (7th day - and long - (118th day - term storage. Formed AgNPs were characterized by a UV–vis Spectroscopy, Transmission Electron Microscope (TEM, Dynamic light scattering (DLS and Zeta-potential (ZP. The obtained results revealed that a short-term stability of the synthesized AgNPs was greatly influenced by a citrate stabilizer with the absence of gelatin. Smaller-sized AgNPs (average particle diameter of 3 nm, roughly spherical in a shape, were obtained with a narrow size distribution. The very negative value of the Zeta-potential confirmed a strong stability of the citrate capped AgNPs. However, a surface coating of the AgNPs by a gelatin/citrate stabilizer was found to be a dominant contributor in improving a long-term stability of the AgNPs (average particle diameter of 26 nm. The use of gelatin in mixed stabilizer solution provided the AgNPs with higher monodispersity and a controllable size after both the short and long-term storage.

Magnetic properties of nickel nanowires decorated with cobalt nanoparticles fabricated by two step electrochemical deposition technique

Energy Technology Data Exchange (ETDEWEB)

Maaz, K., E-mail: maaz@impcas.ac.cn [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Nanomaterials Research Group, Physics Division, PINSTECH, Nilore, 45650, Islamabad (Pakistan); Duan, J.L. [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Karim, S. [Nanomaterials Research Group, Physics Division, PINSTECH, Nilore, 45650, Islamabad (Pakistan); Chen, Y.H.; Yao, H.J.; Mo, D.; Sun, Y.M. [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Liu, J., E-mail: j.liu@impcas.ac.cn [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

2016-10-01

We demonstrate fabrication and magnetic characterization of novel nanostructures composed of Ni nanowires decorated with Co nanoparticles by two step etching and electrochemical deposition in polycarbonate template. Structural analysis confirmed the formation of nickel nanowires with diameter of 62 nm which are surrounded by cobalt nanoparticles of about 15 nm in diameter. By electron microscopy analyses it is evident that the nanoparticles are distributed on the surface of the nanowires. Analysis of magnetization data indicates that ferromagnetic Ni nanowires exhibit an easy axis of magnetization parallel to the wire long-axis while the angular dependence of coercivity indicates that magnetization reversal occurs through the curling process in these nanowires. An exchange bias accompanied by vertical shift in magnetization was observed below ∼20 K, measured under a cooling field of 1 kOe, which is attributed to the spin interactions between the spin-glass like surface layer and ferromagnetic core of the nanowires and nanoparticles. - Highlights: • Co-decorated Ni nanowires were fabricated by two-step electrodeposition technique. • The nanoparticles are distributed on the surface of nanowires. • Magnetization reversal occurs through the curling process in the nanowires. • Temperature dependent coercivity follows thermal activation model.

Formation of gold decorated porphyrin nanoparticles and evaluation of their photothermal and photodynamic activity

Energy Technology Data Exchange (ETDEWEB)

Chen, Ruey-Juen; Chen, Po-Chung [Division of Family Medicine, Department of Community Medicine, Taoyuan Armed Forces General Hospital, Taiwan, ROC (China); Prasannan, Adhimoorthy; Vinayagam, Jayaraman; Huang, Chun-Chiang; Chou, Peng-Yi; Weng, Cheng-Chih [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan, ROC (China); Tsai, Hsieh Chih, E-mail: h.c.tsai@mail.ntust.edu.tw [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan, ROC (China); Lin, Shuian-Yin [National Applied Research Laboratories, Instrument Technology Research Center, Hsinchu 300 (China)

2016-06-01

A core-shell gold (Au) nanoparticle with improved photosensitization have been successfully fabricated using Au nanoparticles and 5,10,15,20 tetrakis pentafluorophenyl)-21H,23H-porphine (PF6) dye, forming a dyad through molecular self-assembly. Au nanoparticles were decorated on the shell and PF6 was placed in the core of the nanoparticles. Highly stable Au nanoparticles were achieved using PF6 with poly(N-vinylcaprolactam-co-N-vinylimidazole)-g-poly(D,L-lactide) graft copolymer hybridization. This was compared with hybridization using cetyltrimethylammonium bromide and polyethylene glycol-b-poly(D,L-lactide) for shell formation with PF6–Au. The resulting PF6-poly(N-vinylcaprolactam-co-N-vinylimidazole)-g-poly(D,L-lactide)-Au core–shell nanoparticle were utilized for photothermal and photodynamic activities. The spectroscopic analysis and zeta potential values of micelles revealed the presence of a thin Au layer coated on the PF6 nanoparticle surface, which generally enhanced the thermal stability of the gold nanoparticles and the photothermal effect of the shell. The core–shell PF6–Au nanoparticles were avidly taken up by cells and demonstrated cellular phototoxicity upon irradiation with 300 W halogen lamps. The structural arrangement of PF6 dyes in the core–shell particles assures the effectiveness of singlet oxygen production. The study verifies that PF6 particles when companied with Au nanoparticles as PF6–Au have possible combinational applications in photodynamic and photothermal therapies for cancer cells because of their high production of singlet oxygen and heat. - Highlights: • Core-shell PF6-Au nanoparticles were prepared through a graft-copolymer-based micelle with photosensitization and photothermic behavior. • PF6 was placed in the core of the nanoparticles through molecular self-assembly. Au nanoparticles were decorated on this 60-nm-diameter shell. • Core-shell PF6-Au nanoparticles demonstrated effective singlet oxygen production

Formation of gold decorated porphyrin nanoparticles and evaluation of their photothermal and photodynamic activity

International Nuclear Information System (INIS)

Chen, Ruey-Juen; Chen, Po-Chung; Prasannan, Adhimoorthy; Vinayagam, Jayaraman; Huang, Chun-Chiang; Chou, Peng-Yi; Weng, Cheng-Chih; Tsai, Hsieh Chih; Lin, Shuian-Yin

2016-01-01

A core-shell gold (Au) nanoparticle with improved photosensitization have been successfully fabricated using Au nanoparticles and 5,10,15,20 tetrakis pentafluorophenyl)-21H,23H-porphine (PF6) dye, forming a dyad through molecular self-assembly. Au nanoparticles were decorated on the shell and PF6 was placed in the core of the nanoparticles. Highly stable Au nanoparticles were achieved using PF6 with poly(N-vinylcaprolactam-co-N-vinylimidazole)-g-poly(D,L-lactide) graft copolymer hybridization. This was compared with hybridization using cetyltrimethylammonium bromide and polyethylene glycol-b-poly(D,L-lactide) for shell formation with PF6–Au. The resulting PF6-poly(N-vinylcaprolactam-co-N-vinylimidazole)-g-poly(D,L-lactide)-Au core–shell nanoparticle were utilized for photothermal and photodynamic activities. The spectroscopic analysis and zeta potential values of micelles revealed the presence of a thin Au layer coated on the PF6 nanoparticle surface, which generally enhanced the thermal stability of the gold nanoparticles and the photothermal effect of the shell. The core–shell PF6–Au nanoparticles were avidly taken up by cells and demonstrated cellular phototoxicity upon irradiation with 300 W halogen lamps. The structural arrangement of PF6 dyes in the core–shell particles assures the effectiveness of singlet oxygen production. The study verifies that PF6 particles when companied with Au nanoparticles as PF6–Au have possible combinational applications in photodynamic and photothermal therapies for cancer cells because of their high production of singlet oxygen and heat. - Highlights: • Core-shell PF6-Au nanoparticles were prepared through a graft-copolymer-based micelle with photosensitization and photothermic behavior. • PF6 was placed in the core of the nanoparticles through molecular self-assembly. Au nanoparticles were decorated on this 60-nm-diameter shell. • Core-shell PF6-Au nanoparticles demonstrated effective singlet oxygen production

Controlled self-decoration of Mo6SyIz (8.2 ≤ y + z ≤ 10) nanowires and their transformation to MoS2 nanotubes with gold nanoparticles

International Nuclear Information System (INIS)

Kovič, Andrej; Vengust, Damjan; Vilfan, Mojca; Mrzel, Aleš

2013-01-01

Nanowires and nanotubes decorated with gold nanoparticles are known for their excellent sensing and catalytic properties. However, the decoration of transition–metal dichalcogenide nanotubes can be very complex. Here we report on a simple procedure that enables efficient production and purification of thin bundles of Mo 6 S y I z (8.2 ≤ y + z ≤ 10) nanowires decorated with gold nanoparticles and their transformation to gold-decorated MoS 2 nanotubes. We isolated several hundred milligrams of nanowire bundles that were several microns long with average diameters of around 40 nm, and formed a stable dispersion in water without added surfactants. Gold nanoparticles were directly deposited on the nanowire bundles either in a solution or on a substrate at room temperature in a single-step reaction without any additional reducing reagents. The number of gold nanoparticles on a nanowire bundle is controlled by changing the concentration of chloroauric acid HAuCl 4 ·3H 2 O in the solution. Since the nanowires can serve as precursor crystals for fabrication of nanotubes, we were able to transform gold-decorated nanowires and produce gold-decorated MoS 2 nanotubes

Hierarchical nanoflowers assembled with Au nanoparticles decorated ZnO nanosheets toward enhanced photocatalytic properties

DEFF Research Database (Denmark)

Yu, Cuiyan; Yu, Yanlong; Xu, Tao

2017-01-01

Hierarchical nanoflowers assembled with Au nanoparticles (NPs) decorated ZnO nanosheets (Au-ZnO nanosheet flowers, AZNSFs) were successful synthesized. The AZNSFs showed more efficient activity to photodegradation of RhB than that of pure ZnO nanosheet flowers and commercial ZnO nanopowders. The ...

Synthesis and magnetic properties of highly dispersed tantalum carbide nanoparticles decorated on carbon spheres

CSIR Research Space (South Africa)

Bhattacharjee, K

2016-01-01

Full Text Available The decoration of carbon spheres (CS) by highly dispersed tantalum carbide nanoparticles (TaC NPs) was achieved, for the first time by a unique carbothermal reduction method at 1350 °C for 30 min under reduced oxygen partial pressure. TaC NPs...

Maghemite nanoparticle-decorated hollow fiber electromembrane extraction combined with dispersive liquid-liquid microextraction for the determination of thymol from Carum copticum

DEFF Research Database (Denmark)

Khajeh, Mostafa; Pedersen-Bjergaard, Stig; Bohlooli, Mousa

2017-01-01

BACKGROUND A novel technique using maghemite nanoparticle-decorated hollow fibers to assist electromembrane extraction is proposed. Electromembrane extraction combined with dispersive liquid–liquid microextraction (EME-DLLME) was applied for the extraction of thymol from Carum copticum, followed...... by gas chromatography with flame ionization detection (GC-FID). RESULTS The use of maghemite nanoparticle-decorated hollow fibers was found to improve the extraction efficiency of thymol significantly. Important operational parameters, including pH of acceptor phase, extraction time, voltage...

Conductive Adhesive Based on Mussel-Inspired Graphene Decoration with Silver Nanoparticles.

Science.gov (United States)

Casa, Marcello; Sarno, Maria; Liguori, Rosalba; Cirillo, Claudia; Rubino, Alfredo; Bezzeccheri, Emanuele; Liu, Johan; Ciambelli, Paolo

2018-02-01

Decoration with silver nanoparticles was obtained by coating graphene with a polydopamine layer, able to induce spontaneous metallic nanoparticles formation without any specific chemical interfacial modifier, neither using complex instrumentation. The choice of dopamine was inspired by the composition of adhesive proteins in mussels, related to their robust attach to solid surfaces. The synthesis procedure started from graphite and involved eco-friendly compounds, such as Vitamin C and glucose as reducing agent and water as reaction medium. Silver decorated graphene was inserted as secondary nanofiller in the formulation of a reference conductive adhesive based on epoxy resin and silver flakes. A wide characterization of the intermediate materials obtained along the step procedure for the adhesive preparation was carried out by several techniques. We have found that the presence of nanofiller yields, in addition to an improvement of the thermal conductivity (up to 7.6 W/m · K), a dramatic enhancement of the electrical conductivity of the adhesive. In particular, starting from 3 · 102 S/cm of the reference adhesive, we obtained a value of 4 · 104 S/cm at a nanofiller concentration of 11.5 wt%. The combined double filler conductivity was evaluated by Zallen's model. The effect of the temperature on the resistivity of the adhesive has been also studied.

The correlation between gelatin macroscale differences and nanoparticle properties: providing insight into biopolymer variability.

Science.gov (United States)

Stevenson, André T; Jankus, Danny J; Tarshis, Max A; Whittington, Abby R

2018-05-21

From therapeutic delivery to sustainable packaging, manipulation of biopolymers into nanostructures imparts biocompatibility to numerous materials with minimal environmental pollution during processing. While biopolymers are appealing natural based materials, the lack of nanoparticle (NP) physicochemical consistency has decreased their nanoscale translation into actual products. Insights regarding the macroscale and nanoscale property variation of gelatin, one of the most common biopolymers already utilized in its bulk form, are presented. Novel correlations between macroscale and nanoscale properties were made by characterizing similar gelatin rigidities obtained from different manufacturers. Samples with significant differences in clarity, indicating sample purity, obtained the largest deviations in NP diameter. Furthermore, a statistically significant positive correlation between macroscale molecular weight dispersity and NP diameter was determined. New theoretical calculations proposing the limited number of gelatin chains that can aggregate and subsequently get crosslinked for NP formation were presented as one possible reason to substantiate the correlation analysis. NP charge and crosslinking extent were also related to diameter. Lower gelatin sample molecular weight dispersities produced statistically smaller average diameters (<75 nm), and higher average electrostatic charges (∼30 mV) and crosslinking extents (∼95%), which were independent of gelatin rigidity, conclusions not shown in the literature. This study demonstrates that the molecular weight composition of the starting material is one significant factor affecting gelatin nanoscale properties and must be characterized prior to NP preparation. Identifying gelatin macroscale and nanoscale correlations offers a route toward greater physicochemical property control and reproducibility of new NP formulations for translation to industry.

Hydrogen peroxide sensor: Uniformly decorated silver nanoparticles on polypyrrole for wide detection range

Energy Technology Data Exchange (ETDEWEB)

Nia, Pooria Moozarm, E-mail: pooriamn@yahoo.com; Meng, Woi Pei, E-mail: pmwoi@um.edu.my; Alias, Y., E-mail: yatimah70@um.edu.my

2015-12-01

Graphical abstract: - Highlights: • Electrochemical method was used for depositing silver nanoparticles and polypyrrole. • Silver nanoparticles (25 nm) were uniformly decorated on electrodeposited polypyrrole. • (Ag(NH{sub 3}){sub 2}OH) precursor showed better electrochemical performance than (AgNO{sub 3}). • The sensor showed superior performance toward H{sub 2}O{sub 2}. - Abstract: Electrochemically synthesized polypyrrole (PPy) decorated with silver nanoparticles (AgNPs) was prepared and used as a nonenzymatic sensor for hydrogen peroxide (H{sub 2}O{sub 2}) detection. Polypyrrole was fabricated through electrodeposition, while silver nanoparticles were deposited on polypyrrole by the same technique. The field emission scanning electron microscopy (FESEM) images showed that the electrodeposited AgNPs were aligned along the PPy uniformly and the mean particle size of AgNPs is around 25 nm. The electrocatalytic activity of AgNPs-PPy-GCE toward H{sub 2}O{sub 2} was studied using chronoamperometry and cyclic voltammetry. The first linear section was in the range of 0.1–5 mM with a limit of detection of 0.115 μmol l{sup −1} and the second linear section was raised to 120 mM with a correlation factor of 0.256 μmol l{sup −1} (S/N of 3). Moreover, the sensor presented excellent stability, selectivity, repeatability and reproducibility. These excellent performances make AgNPs-PPy/GCE an ideal nonenzymatic H{sub 2}O{sub 2} sensor.

Mammalian cell growth on gold nanoparticle-decorated substrates is influenced by the nanoparticle coating

Directory of Open Access Journals (Sweden)

Christina Rosman

2014-12-01

Full Text Available In this work, we study epithelial cell growth on substrates decorated with gold nanorods that are functionalized either with a positively charged cytotoxic surfactant or with a biocompatible polymer exhibiting one of two different end groups, resulting in a neutral or negative surface charge of the particle. Upon observation of cell growth for three days by live cell imaging using optical dark field microscopy, it was found that all particles supported cell adhesion while no directed cell migration and no significant particle internalization occurred. Concerning cell adhesion and spreading as compared to cell growth on bare substrates after 3 days of incubation, a reduction by 45% and 95%, respectively, for the surfactant particle coating was observed, whereas the amino-terminated polymer induced a reduction by 30% and 40%, respectively, which is absent for the carboxy-terminated polymer. Furthermore, interface-sensitive impedance spectroscopy (electric cell–substrate impedance sensing, ECIS was employed in order to investigate the micromotility of cells added to substrates decorated with various amounts of surfactant-coated particles. A surface density of 65 particles/µm2 (which corresponds to 0.5% of surface coverage with nanoparticles diminishes micromotion by 25% as compared to bare substrates after 35 hours of incubation. We conclude that the surface coating of the gold nanorods, which were applied to the basolateral side of the cells, has a recognizable influence on the growth behavior and thus the coating should be carefully selected for biomedical applications of nanoparticles.

Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent

Energy Technology Data Exchange (ETDEWEB)

Holtz, R D; Souza Filho, A G; Alves, O L [Laboratorio de Quimica do Estado Solido (LQES), Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13081-970, Campinas-SP (Brazil); Brocchi, M; Martins, D [Departamento de Genetica, Evolucao and Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Duran, N, E-mail: rholtz@iqm.unicamp.br, E-mail: agsf@fisica.ufc.br, E-mail: oalves@iqm.unicamp.br [Laboratorio de Quimica Biologica, Instituto de Quimica, Universidade Estadual de Campinas, Campinas-SP (Brazil)

2010-05-07

In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

Copoly(Imide Siloxane) Abhesive Materials with Varied Siloxane Oligomer Length

Science.gov (United States)

Wohl, Christopher J.; Atkins, Brad M.; Belcher, Marcus A.; Connell, John W.

2010-01-01

Incorporation of PDMS moieties into a polyimide matrix lowered the surface energy resulting in enhanced adhesive interactions. Polyimide siloxane materials were generated using amine-terminated PDMS oligomers of different lengths to study changes in surface migration behavior, phase segregation, mechanical, thermal, and optical properties. These materials were characterized using contact angle goniometry, tensile testing, and differential scanning calorimetry. The surface migration behavior of the PDMS component depended upon the siloxane molecular weight as indicated by distinct relationships between PDMS chain length and advancing water contact angles. Similar correlations were observed for percent elongation values obtained from tensile testing, while the addition of PDMS reduced the modulus. High fidelity topographical modification via laser ablation patterning further reduced the polyimide siloxane surface energy. Initial particulate adhesion testing experiments demonstrated that polyimide siloxane materials exhibited greater abhesive interactions relative to their respective homopolyimides.

Synthesis, Characterization, Topographical Modification, and Surface Properties of Copoly(Imide Siloxane)s

Science.gov (United States)

Wohl, Christopher J.; Atkins, Brad M.; Belcher, Marcus A.; Connell, John W.

2012-01-01

Novel copoly(imide siloxane)s were synthesized from commercially available aminopropyl terminated siloxane oligomers, aromatic dianhydrides, and diamines. This synthetic approach produced copolymers with well-defined siloxane blocks linked with imide units in a random fashion. The copoly(amide acid)s were characterized by solution viscosity and subsequently used to cast thin films followed by thermal imidization in an inert atmosphere. Thin films were characterized using contact angle goniometry, attenuated total reflection Fourier transform infrared spectroscopy, confocal and optical microscopy, and tensile testing. Adhesion of micronsized particles was determined quantitatively using a sonication device. The polydimethylsiloxane (PDMS) moieties lowered the copolymer surface energy due to migration of siloxane moieties to the film s surface, resulting in a notable reduction in particle adhesion. A further reduction in particle adhesion was achieved by introducing topographical features on a scale of several to tens of microns by a laser ablation technique.

Application of reactive siloxane prepolymers for the synthesis of thermoplastic poly(ester–siloxanes and poly(ester–ether–siloxanes

Directory of Open Access Journals (Sweden)

VESNA V. ANTIC

2007-02-01

Full Text Available Thermoplastic poly(ester–siloxanes (TPES and poly(ester–ether–siloxane s, (TPEES, based on poly(butylene terephthalate (PBT as the hard segment and different siloxane-prepolymers as the soft segments, were prepared. The TPES and TPEES were synthesized by catalyzed two-step transesterification from dimethyl terephthalate, (DMT, 1,4-butanediol, (BD and a siloxane-prepolymer. Incorporation of dicarboxypropyl- or disilanol-terminated poly(dimethylsiloxanes (PDMS into the polar poly(butylene terephthalate chains resulted in rather inhomogeneous TPES copolymers, which was a consequence of a prononuced phase separation of the polar and non-polar reactants during synthesis. Two concepts were employed to avoid or reduce phase separation: 1 the use of siloxane-containing triblock prepolymers with hydrophilic terminal blocks, such as ethylene oxide (EO, poly(propylene oxide (PPO or poly(caprolactone (PLC when the terminal blocks serve as a compatibilizer between the extremely non-polar PDMS and the polar DMT and BD, and 2 the use of a high-boiling solvent (1,2,4-trichlorobenzene during the first phase of the reaction. Homogeneity was significantly improved in the case of copolymers based on PCL–PDMS–PCL.

Quantum dot-decorated semiconductor micro- and nanoparticles: A review of their synthesis, characterization and application in photocatalysis.

Science.gov (United States)

Bajorowicz, Beata; Kobylański, Marek P; Gołąbiewska, Anna; Nadolna, Joanna; Zaleska-Medynska, Adriana; Malankowska, Anna

2018-06-01

Quantum dot (QD)-decorated semiconductor micro- and nanoparticles are a new class of functional nanomaterials that have attracted considerable interest for their unique structural, optical and electronic properties that result from the large surface-to-volume ratio and the quantum confinement effect. In addition, because of QDs' excellent light-harvesting capacity, unique photoinduced electron transfer, and up-conversion behaviour, semiconductor nanoparticles decorated with quantum dots have been used widely in photocatalytic applications for the degradation of organic pollutants in both the gas and aqueous phases. This review is a comprehensive overview of the recent progress in synthesis methods for quantum dots and quantum dot-decorated semiconductor composites with an emphasis on their composition, morphology and optical behaviour. Furthermore, various approaches used for the preparation of QD-based composites are discussed in detail with respect to visible and UV light-induced photoactivity. Finally, an outlook on future development is proposed with the goal of overcoming challenges and stimulating further research into this promising field. Copyright © 2018 Elsevier B.V. All rights reserved.

A high-performance carbon nanoparticle-decorated graphite felt electrode for vanadium redox flow batteries

International Nuclear Information System (INIS)

Wei, L.; Zhao, T.S.; Zhao, G.; An, L.; Zeng, L.

2016-01-01

Highlights: • Propose a carbon nanoparticle-decorated graphite felt electrode for VRFBs. • The energy efficiency is up to 84.8% at 100 mA cm"−"2. • The new electrode allows the peak power density to reach 508 mW cm"−"2. - Abstract: Increasing the performance of vanadium redox flow batteries (VRFBs), especially the energy efficiency and power density, is critically important to reduce the system cost to a level for widespread commercialization. Unlike conventional VRFBs with flow-through structure, in this work we create a VRFB featuring a flow-field structure with a carbon nanoparticle-decorated graphite felt electrode for the battery. This novel structure, exhibiting a significantly reduced ohmic loss through reducing electrode thickness, an increased surface area and improved electrocatalytic activity by coating carbon nanoparticles, allows the energy efficiency up to 84.8% at a current density of as high as 100 mA cm"−"2 and the peak power density to reach a value of 508 mW cm"−"2. In addition, it is demonstrated that the battery with this proposed structure exhibits a substantially improved rate capability and capacity retention as opposed to conventional flow-through structured battery with thick graphite felt electrodes.

Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nano tubes and Their Use as Magnetically Recyclable Catalysts

International Nuclear Information System (INIS)

He, H.; Gao, C.

2011-01-01

We report a facile approach to prepare Fe 3 O 4 /Pt nanoparticles decorated carbon nano tubes (CNTs). The superparamagnetic Fe 3 O 4 nanoparticles with average size of 45 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl 3 . The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe 3 O 4 nanoparticles and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanoparticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe 3 O 4 /Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

Non-Enzymatic Glucose Biosensor Based on CuO-Decorated CeO2 Nanoparticles

Directory of Open Access Journals (Sweden)

Panpan Guan

2016-08-01

Full Text Available Copper oxide (CuO-decorated cerium oxide (CeO2 nanoparticles were synthesized and used to detect glucose non-enzymatically. The morphological characteristics and structure of the nanoparticles were characterized through transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The sensor responses of electrodes to glucose were investigated via an electrochemical method. The CuO/CeO2 nanocomposite exhibited a reasonably good sensitivity of 2.77 μA mM−1cm−2, an estimated detection limit of 10 μA, and a good anti-interference ability. The sensor was also fairly stable under ambient conditions.

Zinc-decorated silica-coated magnetic nanoparticles for protein binding and controlled release.

Science.gov (United States)

Bele, Marjan; Hribar, Gorazd; Campelj, Stanislav; Makovec, Darko; Gaberc-Porekar, Vladka; Zorko, Milena; Gaberscek, Miran; Jamnik, Janko; Venturini, Peter

2008-05-01

The aim of this study was to be able to reversibly bind histidine-rich proteins to the surface of maghemite magnetic nanoparticles via coordinative bonding using Zn ions as the anchoring points. We showed that in order to adsorb Zn ions on the maghemite, the surface of the latter needs to be modified. As silica is known to strongly adsorb zinc ions, we chose to modify the maghemite nanoparticles with a nanometre-thick silica layer. This layer appeared to be thin enough for the maghemite nanoparticles to preserve their superparamagnetic nature. As a model the histidine-rich protein bovine serum albumin (BSA) was used. The release of the BSA bound to Zn-decorated silica-coated maghemite nanoparticles was analysed using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). We demonstrated that the bonding of the BSA to such modified magnetic nanoparticles is highly reversible and can be controlled by an appropriate change of the external conditions, such as a pH decrease or the presence/supply of other chelating compounds.

Thermal conductivity enhancements and viscosity properties of water based Nanofluid containing carbon nanotubes decorated with ag nanoparticles

Science.gov (United States)

Gu, Yanni; Xu, Sheng; Wu, Xiaoshan

2018-06-01

The water based nanofluid containing carbon nanotube (CNT) decorated with Ag nanoparticles (Ag/CNT) is prepared. Its thermal conductivity ( k) enhancement increases with the thermal filler loading and the decoration quantity of Ag nanoparticles. The low absolute CNT content will decrease the tangles or aggregations among the CNTs, and it will be good at the Brownian motion of CNTs in the water. It has positive effects on the thermal conductivity of nanofluid. With the increase of Ag loading, the average size of Ag nanoparticles increased, and further results in the decrease of dispersing amount of Ag/CNT as the weight of Ag/CNT is fixed. Little dispersing quantity of Ag/CNT makes it possible that the Ag/CNT particles disperse well in the fluid. So it is not easy for CNTs to form aggregation. The high intrinsic k of CNT and the effective thermal conductive networks forming by CNTs and Ag nanoparticles are good at the k enhancement. With temperature increase the k of Ag/CNT nanofluid appears improvement. The study results make it possible to develop high-efficiency nanofluid for advanced thermal management regions.

Thermal conductivity enhancements and viscosity properties of water based Nanofluid containing carbon nanotubes decorated with ag nanoparticles

Science.gov (United States)

Gu, Yanni; Xu, Sheng; Wu, Xiaoshan

2018-01-01

The water based nanofluid containing carbon nanotube (CNT) decorated with Ag nanoparticles (Ag/CNT) is prepared. Its thermal conductivity (k) enhancement increases with the thermal filler loading and the decoration quantity of Ag nanoparticles. The low absolute CNT content will decrease the tangles or aggregations among the CNTs, and it will be good at the Brownian motion of CNTs in the water. It has positive effects on the thermal conductivity of nanofluid. With the increase of Ag loading, the average size of Ag nanoparticles increased, and further results in the decrease of dispersing amount of Ag/CNT as the weight of Ag/CNT is fixed. Little dispersing quantity of Ag/CNT makes it possible that the Ag/CNT particles disperse well in the fluid. So it is not easy for CNTs to form aggregation. The high intrinsic k of CNT and the effective thermal conductive networks forming by CNTs and Ag nanoparticles are good at the k enhancement. With temperature increase the k of Ag/CNT nanofluid appears improvement. The study results make it possible to develop high-efficiency nanofluid for advanced thermal management regions.

Gelatin behaviour in dilute aqueous solution : designing a nanoparticulate formulation

OpenAIRE

Farrugia, Claude; Groves, Michael J.

1999-01-01

Although it has been claimed that nanoparticles can be produced from gelatin, a naturally occurring polypeptide, the commercial conversion of animal collagen to gelatin results in a heterogeneous product with a wide molecular-weight range. This is probably responsible for the widely observed variation in the experimental conditions required for nanoparticle formation. In this study, 0.2% w/v aqueous B225 gelatin solutions were incubated under various conditions of time, temperature, pH an...

Improving g-C3N4 photocatalysis for NOx removal by Ag nanoparticles decoration

International Nuclear Information System (INIS)

Sun, Yanjuan; Xiong, Ting; Ni, Zilin; Liu, Jie; Dong, Fan; Zhang, Wei; Ho, Wing-Kei

2015-01-01

Graphical abstract: Ag/g-C 3 N 4 nanocomposites were prepared via a facile method for enhanced photocatalytic NO x removal due to surface plasmon resonance of Ag. - Highlights: • The Ag/g-C 3 N 4 nanocomposites were prepared using urea as the precursor. • The Ag/g-C 3 N 4 nanocomposites were applied in removal of NO x in air. • The Ag nanoparticles enhanced the photocatalytic activity of g-C 3 N 4 . • The surface plasmon resonance of Ag played a key role in photocatalysis. - Abstract: In order to overcome the intrinsic drawback of pristine g-C 3 N 4 , we prepared g-C 3 N 4 nanosheets with enhanced photocatalytic performance by Ag nanoparticles decoration using urea as the precursor. It was revealed that the monodispersed Ag nanoparticles were deposited on the surface of g-C 3 N 4 nanosheets. The Ag/g-C 3 N 4 nanocomposites were applied in removal of NO x in air under visible light irradiation. The results showed that the decoration of Ag nanoparticles not only enhanced the photocatalytic activity of g-C 3 N 4 nanosheets, but also benefited the oxidation of NO to final products. The increased visible light absorption arising from the surface plasmon resonance of Ag and improved separation and transfer of photoinduced carriers over Ag/g-C 3 N 4 composites were demonstrated by the UV–vis diffuse reflectance spectra and photoluminescence spectra, respectively. It was therefore proposed that the enhanced photocatalytic activity of Ag/g-C 3 N 4 composites could be attributed to the extended light response range and enhanced charge separation due to the introduction of Ag nanoparticles.

Silver nanoparticles decorated carboxylate functionalized SiO2, New nanocomposites for non-enzymatic detection of glucose and hydrogen peroxide

International Nuclear Information System (INIS)

Ensafi, Ali A.; Zandi-Atashbar, N.; Rezaei, B.; Ghiaci, M.; Taghizadeh, M.

2016-01-01

Highlights: • Silver nanoparticles decorated carboxylates functionalized SiO 2 were prepared. • Ligands are bonding to silica support as SiO 2 –pro–NH 2 and SiO 2 –pro–NH–cyanuric–NH 2 . • These nanomaterials were used as electrochemical sensors for H 2 O 2 and glucose detection. • H 2 O 2 and glucose could be detected as low as 0.094 and 0.33 μmol L −1 , respectively. - Abstract: Here, two different nanocomposites are prepared based on the decoration of silver nanoparticles (AgNPs) on carboxylated SiO 2 . SiO 2 was functionalized with two different carboxylate ligands to stabilize silver nanoparticles on them, using two different organic bondings. Then, AgNPs were decorated successfully on the surface of the functionalized SiO 2 . The functionalized SiO 2 and AgNPs-functionalized SiO 2 were characterized using Fourier transform infrared spectroscopy, elemental analyses, and Transmission electron microscopy (TEM). For further characterization, the generated nanoparticles were employed as modifiers in the preparation of carbon paste electrodes (CPEs). Then, cyclic voltammetry and electrochemical impedance spectroscopy were used to study their electrochemical behavior. The electrochemical data exhibited that the modifications of CPE led to easier electron transfers rather than the bare and unmodified SiO 2 /CPE due to the presence of functionalized SiO 2 in accompany with electrocatalytic effects of the decorated silver nanoparticles. Furthermore, the modified–CPEs were examined as non–enzymatic H 2 O 2 and glucose sensors using electrochemical techniques including cyclic voltammetry and hydrodynamic chronoamperometric. Electrochemical results represented that the modified-CPE is efficient and sensitive for H 2 O 2 and glucose detection as low as 0.094 and 0.33 μmol L −1 , respectively. At last, the practical applications of these sensors were also evaluated by analyzing H 2 O 2 and glucose in the presence of common interfering species

Oxidation of siloxanes during biogas combustion and nanotoxicity of Si-based particles released to the atmosphere.

Science.gov (United States)

Tansel, Berrin; Surita, Sharon C

2014-01-01

Siloxanes have been detected in the biogas produced at municipal solid waste landfills and wastewater treatment plants. When oxidized, siloxanes are converted to silicon oxides. The objectives of this study were to evaluate the transformation of siloxanes and potential nanotoxicity of Si-based particles released to the atmosphere from the gas engines which utilize biogas. Data available from nanotoxicity studies were used to assess the potential health risks associated with the inhalation exposure to Si-based nanoparticles. Silicon dioxide formed from siloxanes can range from 5 nm to about 100 nm in diameter depending on the combustion temperature and particle clustering characteristics. In general, silicon dioxide particles formed during from combustion process are typically 40-70 nm in diameter and can be described as fibrous dusts and as carcinogenic, mutagenic, astmagenic or reproductive toxic (CMAR) nanoparticles. Nanoparticles deposit in the upper respiratory system, conducting airways, and the alveoli. Size ranges between 5 and 50 nm show effective deposition in the alveoli where toxic effects are higher. In this study the quantities for the SiO₂ formed and release during combustion of biogas were estimated based on biogas utilization characteristics (gas compositions, temperature). The exposure to Si-based particles and potential effects in humans were analyzed in relation to their particle size, release rates and availability in the atmosphere. The analyses showed that about 54.5 and 73 kg/yr of SiO₂ can be released during combustion of biogas containing D4 and D5 at 14.1 mg/m(3) (1 ppm) and 15.1 mg/m(3) (1ppm), respectively, per MW energy yield. Copyright © 2013 Elsevier B.V. All rights reserved.

Alignment of Gold Nanoparticle-Decorated DNA Origami Nanotubes: Substrate Prepatterning versus Molecular Combing.

Science.gov (United States)

Teschome, Bezu; Facsko, Stefan; Gothelf, Kurt V; Keller, Adrian

2015-11-24

DNA origami has become an established technique for designing well-defined nanostructures with any desired shape and for the controlled arrangement of functional nanostructures with few nanometer resolution. These unique features make DNA origami nanostructures promising candidates for use as scaffolds in nanoelectronics and nanophotonics device fabrication. Consequently, a number of studies have shown the precise organization of metallic nanoparticles on various DNA origami shapes. In this work, we fabricated large arrays of aligned DNA origami decorated with a high density of gold nanoparticles (AuNPs). To this end, we first demonstrate the high-yield assembly of high-density AuNP arrangements on DNA origami adsorbed to Si surfaces with few unbound background nanoparticles by carefully controlling the concentrations of MgCl2 and AuNPs in the hybridization buffer and the hybridization time. Then, we evaluate two methods, i.e., hybridization to prealigned DNA origami and molecular combing in a receding meniscus, with respect to their potential to yield large arrays of aligned AuNP-decorated DNA origami nanotubes. Because of the comparatively low MgCl2 concentration required for the efficient immobilization of the AuNPs, the prealigned DNA origami become mobile and displaced from their original positions, thereby decreasing the alignment yield. This increased mobility, on the other hand, makes the adsorbed origami susceptible to molecular combing, and a total alignment yield of 86% is obtained in this way.

Ru-decorated Pt nanoparticles on N-doped multi-walled carbon nanotubes by atomic layer deposition for direct methanol fuel cells

DEFF Research Database (Denmark)

Johansson, Anne-Charlotte Elisabeth Birgitta; Yang, R.B.; Haugshøj, K.B.

2013-01-01

We present atomic layer deposition (ALD) as a new method for the preparation of highly dispersed Ru-decorated Pt nanoparticles for use as catalyst in direct methanol fuel cells (DMFCs). The nanoparticles were deposited onto N-doped multi-walled carbon nanotubes (MWCNTs) at 250 °C using trimethyl......(methylcyclopentadienyl)platinum MeCpPtMe3, bis(ethylcyclopentadienyl)ruthenium Ru(EtCp)2 and O2 as the precursors. Catalysts with 5, 10 and 20 ALD Ru cycles grown onto the CNT-supported ALD Pt nanoparticles (150 cycles) were prepared and tested towards the electro-oxidation of CO and methanol, using cyclic voltammetry...... and chronoamperometry in a three-electrode electrochemical set-up. The catalyst decorated with 5 ALD Ru cycles was of highest activity in both reactions, followed by the ones with 10 and 20 ALD Ru cycles. It is demonstrated that ALD is a promising technique in the field of catalysis as highly dispersed nanoparticles...

Antioxidative study of Cerium Oxide nanoparticle functionalised PCL-Gelatin electrospun fibers for wound healing application

Directory of Open Access Journals (Sweden)

Hilal Ahmad Rather

2018-06-01

Full Text Available Skin wound healing involves a coordinated cellular response to achieve complete reepithelialisation. Elevated levels of reactive oxygen species (ROS in the wound environment often pose a hindrance in wound healing resulting in impaired wound healing process. Cerium oxide nanoparticles (CeNPs have the ability to protect the cells from oxidative damage by actively scavenging the ROS. Furthermore, matrices like nanofibers have also been explored for enhancing wound healing. In the current study CeNP functionalised polycaprolactone (PCL-gelatin nanofiber (PGNPNF mesh was fabricated by electrospinning and evaluated for its antioxidative potential. Wide angle XRD analysis of randomly oriented nanofibers revealed ∼2.6 times reduced crystallinity than pristine PCL which aided in rapid degradation of nanofibers and release of CeNP. However, bioactive composite made between nanoparticles and PCL-gelatin maintained the fibrous morphology of PGNPNF upto 14 days. The PGNPNF mesh exhibited a superoxide dismutase (SOD mimetic activity due to the incorporated CeNPs. The PGNPNF mesh enhanced proliferation of 3T3-L1 cells by ∼48% as confirmed by alamar blue assay and SEM micrographs of cells grown on the nanofibrous mesh. Furthermore, the PGNPNF mesh scavenged ROS, which was measured by relative DCF intensity and fluorescence microscopy; and subsequently increased the viability and proliferation of cells by three folds as it alleviated the oxidative stress. Overall, the results of this study suggest the potential of CeNP functionalised PCL-gelatin nanofibrous mesh for wound healing applications.

Eco-friendly synthesis of gelatin-capped bimetallic Au-Ag nanoparticles for chemiluminescence detection of anticancer raloxifene hydrochloride.

Science.gov (United States)

Alarfaj, Nawal A; El-Tohamy, Maha F

2016-09-01

This study described the utility of green analytical chemistry in the synthesis of gelatin-capped silver, gold and bimetallic gold-silver nanoparticles (NPs). The preparation of nanoparticles was based on the reaction of silver nitrate or chlorauric acid with a 1.0 wt% aqueous gelatin solution at 50°C. The gelatin-capped silver, gold and bimetallic NPs were characterized using transmission electron microscopy, UV-vis, X-ray diffraction and Fourier transform infrared spectroscopy, and were used to enhance a sensitive sequential injection chemiluminescence luminol-potassium ferricyanide system for determination of the anticancer drug raloxifene hydrochloride. The developed method is eco-friendly and sensitive for chemiluminescence detection of the selected drug in its bulk powder, pharmaceutical injections and biosamples. After optimizing the conditions, a linear relationship in the range of 1.0 × 10(-9) to 1.0 × 10(-1)  mol/L was obtained with a limit of detection of 5.0 × 10(-10)  mol/L and a limit of quantification of 1.0 × 10(-9)  mol/L. Statistical treatment and method validation were performed based on ICH guidelines. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Optical studies of CdSe/HgSe and CdSe/Ag2Se core/shell nanoparticles embedded in gelatin

International Nuclear Information System (INIS)

Azhniuk, Yu M; Dzhagan, V M; Valakh, M Ya; Raevskaya, A E; Stroyuk, A L; Kuchmiy, S Ya; Zahn, D R T

2008-01-01

CdSe/HgSe and CdSe/Ag 2 Se core-shell nanoparticles are obtained by colloidal synthesis from aqueous solutions in the presence of gelatin. Optical absorption, luminescence, and Raman spectra of the nanoparticles obtained are measured. The variation of the optical spectra of CdSe/HgSe and CdSe/Ag 2 Se core-shell nanoparticles with the shell thickness is discussed. Sharp non-monotonous variation of the photoluminescence spectra at low shell coverage is observed.

Controlled Antibiotic Delivery by Gelatin Nanospheres: Optimization, Characterization and Antibacterial Evaluation

Directory of Open Access Journals (Sweden)

Shahrzad Fathollahipour

2016-10-01

Full Text Available The present work focuses on preparation and characterization of erythromycin loaded gelatin nanoparticles through nanoprecipitation method. The procedure consists of the addition of the aqueous gelatin solution to the non-solvent phase containing Lutherol F127. Three different measures of cross-linker and polymer concentration were also examined, and the optimum concentration was found. The morphology of gelatin nanoparticles was characterized by field emission scanning electron microscope. It was shown that the optimal morphology can be achieved at the concentration of 1.25 wt % of gelatin in aqueous phase by addition of 20 mL of glutaraldehyde 5%, as the crosslinking agent. Nanoparticle wet size determination was carried out using a dynamic light scattering system and found to be approximately 100 nm. Furthermore, Erythromycin release studies proved the suitability of these particles as a drug delivery system, at least in the studied 72 hours interval. As suggested by related measurements, these nanoparticles are good candidates for antibacterial agent release in any possible related application.

Gas Sensors Based on Locally Heated Multiwall Carbon Nanotubes Decorated with Metal Nanoparticles

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R. Savu

2015-01-01

Full Text Available We report the design and fabrication of microreactors and sensors based on metal nanoparticle-decorated carbon nanotubes. Titanium adhesion layers and gold films were sputtered onto Si/SiO2 substrates for obtaining the electrical contacts. The gold layers were electrochemically thickened until 1 μm and the electrodes were patterned using photolithography and wet chemical etching. Before the dielectrophoretic deposition of the nanotubes, a gap 1 μm wide and 5 μm deep was milled in the middle of the metallic line by focused ion beam, allowing the fabrication of sensors based on suspended nanotubes bridging the electrodes. Subsequently, the sputtering technique was used for decorating the nanotubes with metallic nanoparticles. In order to test the as-obtained sensors, microreactors (100 μL volume were machined from a single Kovar piece, being equipped with electrical connections and 1/4′′ Swagelok-compatible gas inlet and outlets for controlling the atmosphere in the testing chamber. The sensors, electrically connected to the contact pins by wire-bonding, were tested in the 10−5 to 10−2 W working power interval using oxygen as target gas. The small chamber volume allowed the measurement of fast characteristic times (response/recovery, with the sensors showing good sensitivity.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens.

Science.gov (United States)

Peng, Jian-Min; Lin, Jia-Cheng; Chen, Zhuo-Yu; Wei, Meng-Chao; Fu, Yuan-Xiang; Lu, Shu-Shen; Yu, Dong-Sheng; Zhao, Wei

2017-02-01

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs. Copyright © 2016 Elsevier B.V. All rights reserved.

Localized surface plasmon behavior of Ag-Cu alloy nanoparticles stabilized by rice-starch and gelatin

Energy Technology Data Exchange (ETDEWEB)

Singh, Manish Kumar; Mandal, R. K., E-mail: rkmandal.met@itbhu.ac.in [Department of Metallurgical Engineering, IIT (BHU), Varanasi and DST Unit on Nanoscience and Technology, BHU, Varanasi-221 005 (India); Manda, Premkumar; Singh, A. K. [DefenceMetallurgical Research Laboratory, KanchanBagh, Hyderabad-500058 (India)

2015-10-15

The purpose of this communication was to understand localized surface plasmon behavior of a series of Ag-Cu alloy nanoparticles capped by rice-starch and gelatin. The structures of dried powders were investigated with the help of X-ray diffraction. The analysis revealed Ag-rich and Cu-rich phases with maximum solid solubility of Cu ∼9 atom per cent; 8 atom per cent and Ag ∼ 16 atom per cent; 14 atom per cent in rice-starch and gelatin capped samples respectively. Transmission electron microscope was used for knowing the particle size as well as to supplement FCC phase formations of Ag-rich and Cu-rich solid phases arrived at based on X-ray diffraction studies. The UV-Vis spectra of sols were examined for the formation and stability of alloy nanoparticles. The temporal evolution of LSPR curves gave us to assert that the sol is stable for more than two months. Small angle X-ray scattering in the sol state was extensively utilized to understand nature of suspensions in terms of fractals. Such a study is important for having a correlation between LSPR behaviors with those of nanoparticle dispersion in aqueous media. It is believed that this work will be a contribution to the emerging field of plasmonics that include applications in the area of photophysical processes and photochemical reactions.

Direct Scaffolding of Biomimetic Hydroxyapatite-gelatin Nanocomposites using Aminosilane Cross-linker for Bone Regeneration

OpenAIRE

Chiu, Chi-Kai; Ferreira, Joao; Luo, Tzy-Jiun M.; Geng, Haixia; Lin, Feng-Chang; Ko, Ching-Chang

2012-01-01

Hydroxyapatite-gelatin modified siloxane (GEMOSIL) nanocomposite was developed by coating, kneading and hardening processes to provide formable scaffolding for alloplastic graft applications. The present study aims to characterize scaffolding formability and mechanical properties of GEMOSIL, and to test the in vitro and in vivo biocompatibility of GEMOSIL. Buffer Solution initiated formable paste followed by the sol-gel reaction led to a final hardened composite. Results showed the adequate c...

A phototactic micromotor based on platinum nanoparticle decorated carbon nitride.

Science.gov (United States)

Ye, Zhenrong; Sun, Yunyu; Zhang, Hui; Song, Bo; Dong, Bin

2017-11-30

In this paper, we report a unique phototactic (both positive and negative) micromotor based on platinum nanoparticle decorated carbon nitride. The phototaxis relies on the self-diffusiophoretic mechanism and different surface modifications. The micromotor reported in the current study does not require the addition of any external fuels and shows versatile motion behaviour, i.e. start, stop, directional and programmable motion, which is controlled by light. In addition, since the actuation of the precipitated micromotors at the bottom of a solution using light results in the opacity changes from transparent to translucent, we anticipate that the current micromotor may have potential application in the field of smart windows.

Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nanotubes and Their Use as Magnetically Recyclable Catalysts

Directory of Open Access Journals (Sweden)

Hongkun He

2011-01-01

Full Text Available We report a facile approach to prepare Fe3O4/Pt nanoparticles decorated carbon nanotubes (CNTs. The superparamagnetic Fe3O4 nanoparticles with average size of 4∼5 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl3. The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe3O4 nanopartilces and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanopaticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe3O4/Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

Photocatalytic activity of sonochemically prepared TiO_2 decorated with silver nanoparticles

International Nuclear Information System (INIS)

Michal, R.

2017-01-01

A novel way of titanium dioxide synthesis using non-water environment was investigated. In synthesis, water causes aggregation of particles of titania thus reducing active surface significantly. To avoid this, a non- water environment such as toluene was employed. Reaction between solid precursor and gaseous ammonia was conducted in this environment using dried reactants in tempered glass reactor and irradiated by ultrasonic horn. As prepared powders were then calcinated and decorated with Ag nanoparticles. Photocatalytic activity was determined by TOC method and compared to P25 standard TiO_2. Samples were analysed by XRD and Raman spectroscopy and surface morphology was investigated by SEM. Powders prepared by this method had comparable or higher photocatalytic activity than P25. Ag nanoparticles seem to have no significant impact on photocatalytic activity whatsoever. (authors)

Ethylene glycol oxidation on Pt and Pt-Ru nanoparticle decorated polythiophene/multiwalled carbon nanotube composites for fuel cell applications

International Nuclear Information System (INIS)

Selvaraj, Vaithilingam; Alagar, Muthukaruppan

2008-01-01

A novel supporting material containing polythiophene (PTh) and multiwalled carbon nanotubes (MWCNTs) (PTh-CNTs) is prepared by in situ polymerization of thiophene on carbon nanotubes using FeCl 3 as oxidizing agent under sonication. The prepared polythiophene/CNT composites are further decorated with Pt and Pt-Ru nanoparticles by chemical reduction of the corresponding metal salts using HCHO as reducing agent at pH = 11 (Pt/PTh-CNT and Pt-Ru/PTh-CNT). The fabricated composite films decorated with nanoparticles were investigated towards the electrochemical oxidation of ethylene glycol (EG). The presence of carbon nanotubes in conjugation with a conducting polymer produces a good catalytic effect, which might be due to the higher electrochemically accessible surface areas, electronic conductivity and easier charge-transfer at polymer/electrolyte interfaces, which allows higher dispersion of Pt and Pt-Ru nanoparticles. Such nanoparticle modified PTh-CNT electrodes exhibit better catalytic behavior towards ethylene glycol oxidation. Results show that Pt/PTh-CNT and Pt-Ru/PTh-CNT modified electrodes show enhanced electrocatalytic activity and stability towards the electro-oxidation of ethylene glycol than the Pt/PTh electrodes, which shows that the composite film is more promising for applications in fuel cells

Biotin decorated PLGA nanoparticles containing SN-38 designed for cancer therapy.

Science.gov (United States)

Mehdizadeh, Mozhdeh; Rouhani, Hasti; Sepehri, Nima; Varshochian, Reyhaneh; Ghahremani, Mohammad Hossein; Amini, Mohsen; Gharghabi, Mehdi; Ostad, Seyed Nasser; Atyabi, Fatemeh; Baharian, Azin; Dinarvand, Rassoul

2017-05-01

Active targeted chemotherapy is expected to provide more specific delivery of cytotoxic drugs to the tumor cells and hence reducing the side effects on healthy tissues. Due to the over expression of biotin receptors on cancerous cells as a result of further requirement for rapid proliferations, biotin can be a good candidate as a targeting agent. In this study, biotin decorated PLGA nanoparticles (NPs) containing SN-38 were prepared and in vitro studies were evaluated for their improved anti-cancer properties. In conclusion, biotin targeted PLGA NPs containing SN-38 showed preferential anticancer properties against tumor cells with biotin receptor over expression.

Silver nanoparticles with gelatin nanoshells: photochemical facile green synthesis and their antimicrobial activity

International Nuclear Information System (INIS)

Pourjavadi, Ali; Soleyman, Rouhollah

2011-01-01

In the current study, a facile green synthesis of silver-gelatin core–shell nanostructures (spherical, spherical/cubic hybrid, and cubic, DLS diameter: 4.1–6.9 nm) is reported via the wet chemical synthesis procedure. Sunlight-UV as an available reducing agent cause mild reduction of silver ions into the silver nanoparticles (Ag-NPs). Gelatin protein, as an effective capping/shaping agent, was used in the reaction to self-assemble silver nanostructures. The formation of silver nanostructures and their self-assembly pattern was confirmed by SEM, AFM, and TEM techniques. Further investigations were carried out using zeta-potential, UV–Vis, FTIR, GPC, and TGA/DTG/DTA data. The prepared Ag-NPs showed proper and acceptable antimicrobial activity against three classes of microorganisms (Escherichia coli Gram-negative bacteria, Staphylococcus aureus Gram-positive bacteria, and Candida albicans fungus). The antibacterial and antifungal Ag-NPs exhibit good stability in solution and can be considered as promising candidates for a wide range of biomedical applications.

Silver nanoparticles with gelatin nanoshells: photochemical facile green synthesis and their antimicrobial activity

Science.gov (United States)

Pourjavadi, Ali; Soleyman, Rouhollah

2011-10-01

In the current study, a facile green synthesis of silver-gelatin core-shell nanostructures (spherical, spherical/cubic hybrid, and cubic, DLS diameter: 4.1-6.9 nm) is reported via the wet chemical synthesis procedure. Sunlight-UV as an available reducing agent cause mild reduction of silver ions into the silver nanoparticles (Ag-NPs). Gelatin protein, as an effective capping/shaping agent, was used in the reaction to self-assemble silver nanostructures. The formation of silver nanostructures and their self-assembly pattern was confirmed by SEM, AFM, and TEM techniques. Further investigations were carried out using zeta-potential, UV-Vis, FTIR, GPC, and TGA/DTG/DTA data. The prepared Ag-NPs showed proper and acceptable antimicrobial activity against three classes of microorganisms ( Escherichia coli Gram-negative bacteria, Staphylococcus aureus Gram-positive bacteria, and Candida albicans fungus). The antibacterial and antifungal Ag-NPs exhibit good stability in solution and can be considered as promising candidates for a wide range of biomedical applications.

Intercorrelated Ag3PO4 nanoparticles decorated with graphic carbon nitride: Enhanced stability and photocatalytic activities for water treatment

Science.gov (United States)

Ren, Jia; Chai, Yuanyuan; Liu, Qianqian; Zhang, Lu; Dai, Wei-Lin

2017-05-01

The method of decorating Ag3PO4 nanoparticles with carbon nitride material (g-C3N4) is demonstrated as an efficient pathway to remarkably improve the stability and photocatalytic performance of Ag3PO4 nanoparticles which have been widely used in photocatalysis, but limited by the instability. The improved material herein results in the largely enhanced photocatalytic performance for water purification under visible light irradiation, which was nearly 7 times as high as that of pure Ag3PO4. Meanwhile, the as-obtained materials show the unique stable property, mainly contributed by the protection effect of decorated g-C3N4 sheet. Additionally, the radical trapping experiments revealed that the introduction of g-C3N4 transformed the photocatalytic mechanism to some degree, where rad O2- played a more important role. The tremendous enhancement in catalytic performance may be attributed to the larger surface area, controllable particle size and the synergistic effect between Ag3PO4 and g-C3N4, promoting the separation efficiency of the photogenerated electron-hole pairs. The decorating system can in principle be broadly put into use for unstable photocatalysts.

Experimental and theoretical study on field emission properties of zinc oxide nanoparticles decorated carbon nanotubes

International Nuclear Information System (INIS)

Li Xin; Zhou Wei-Man; Liu Wei-Hua; Wang Xiao-Li

2015-01-01

Field emission properties of zinc oxide (ZnO) nanoparticles (NPs) decorated carbon nanotubes (CNTs) are investigated experimentally and theoretically. CNTs are in situ decorated with ZnO NPs during the growth process by chemical vapor deposition using a carbon source from the iron phthalocyanine pyrolysis. The experimental field emission test shows that the ZnO NP decoration significantly improves the emission current from 50 μA to 275 μA at 550 V and the reduced threshold voltage from 450 V to 350 V. The field emission mechanism of ZnO NPs on CNTs is theoretically studied by the density functional theory (DFT) combined with the Penn–Plummer method. The ZnO NPs reconstruct the ZnO–CNT structure and pull down the surface barrier of the entire emitter system to 0.49 eV so as to reduce the threshold electric field. The simulation results suggest that the presence of ZnO NPs would increase the LDOS near the Fermi level and increase the emission current. The calculation results are consistent with the experiment results. (paper)

CdO necklace like nanobeads decorated with PbS nanoparticles: Room temperature LPG sensor

Energy Technology Data Exchange (ETDEWEB)

Sonawane, N.B. [Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon, 425001 M.S. (India); K.A.M.P. & N.K.P. Science College, Pimpalner, Sakri, Dhule, M.S. (India); Baviskar, P.K. [Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon, 425001 M.S. (India); Ahire, R.R. [S.G. Patil Science, Sakri, Dhule, M.S. (India); Sankapal, B.R., E-mail: brsankapal@gmail.com [Nano Materials and Device Laboratory, Department of Applied Physics, Visvesvaraya National Institute of Technology, South Ambazari Road, Nagpur, 440010 M.S. (India)

2017-04-15

Simple chemical route has been employed to grow interconnected nanobeads of CdO having necklace like structure through air annealing of cadmium hydroxide nanowires. This nanobeads of n-CdO with high surface area has been decorated with p-PbS nanoparticles resulting in the formation of nano-heterojunction which has been utilized effectively as room temperature liquefied petroleum gas (LPG) sensor. The room temperature gas response towards C{sub 2}H{sub 5}OH, Cl{sub 2}, NH{sub 3}, CO{sub 2} and LPG was investigated, among which LPG exhibits significant response. The maximum gas response of 51.10% is achieved with 94.54% stability upon exposure of 1176 ppm concentration of LPG at room temperature (27 °C). The resulting parameters like gas response, response and recovery time along with stability studies has been studied and results are discussed herein. - Highlights: • Conversion of Cd(OH){sub 2} nanowires to CdO nanonecklace by air annealing at 290 °C. • Decoration of PbS nanoparticles over CdO nanobeads by SILAR method. • Formation of n-CdO/p-PbS nano-heterojunction as room temperature LPG sensor. • Maximum gas response of 51.10% with 94.54% stability.

Optical and photoelectrical studies of gold nanoparticle-decorated C{sub 60} films

Energy Technology Data Exchange (ETDEWEB)

Dmitruk, N.L., E-mail: dmitruk@isp.kiev.u [Institute for Physics of Semiconductors, National Academy of Sciences of Ukraine, 45 Nauki Prospect, Kyiv 03028 (Ukraine); Borkovskaya, O.Yu.; Mamykin, S.V.; Naumenko, D.O. [Institute for Physics of Semiconductors, National Academy of Sciences of Ukraine, 45 Nauki Prospect, Kyiv 03028 (Ukraine); Meza-Laguna, V. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior, Ciudad Universitaria, A. P. 70-186, C. P. 04510 Mexico D.F. (Mexico); Basiuk Golovataya-Dzhymbeeva, E.V. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico (UNAM), Circuito exterior S/N Ciudad Universitaria, A. P. 70-186, C. P. 04510 Mexico D.F. (Mexico); Lee, I. Puente [Facultad de Quimica, UNAM, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

2010-01-01

Optical and photoelectrical studies were performed on octane-1,8-dithiol cross-linked fullerene films, with supported gold nanoparticles (C{sub 60}-DT-Au). According to high-resolution transmission electron microscopy observations, the average size of obtained gold nanoparticles was about 5 nm, and the shape was spherical. The comparative investigation of optical properties of pristine and cross-linked with octane-1,8-dithiol C{sub 60} films, decorated with gold nanoparticles, found the difference in the extinction coefficient spectra, which was observed also in the photocurrent spectra of barrier heterostructure Au/C{sub 60}/Si. The analysis of dark current-voltage characteristics for Au/C{sub 60}/Si heterostructures showed that the model for them includes the barrier at the C{sub 60}/Si interface and internal barriers in the C{sub 60} layer, caused by the trapping centers. The hopping mechanism of the current transport in the C{sub 60} layer was supplemented with the Poole-Frenkel emission process on these centers, with the barrier height greater for the fullerene C{sub 60} film cross-linked with octane-1,8-dithiol.

Gelatin nanoparticles enhance delivery of hepatitis C virus recombinant NS2 gene.

Science.gov (United States)

Sabet, Salwa; George, Marina A; El-Shorbagy, Haidan M; Bassiony, Heba; Farroh, Khaled Y; Youssef, Tareq; Salaheldin, Taher A

2017-01-01

Development of an effective non-viral vaccine against hepatitis C virus infection is of a great importance. Gelatin nanoparticles (Gel.NPs) have an attention and promising approach as a viable carrier for delivery of vaccine, gene, drug and other biomolecules in the body. The present study aimed to develop stable Gel.NPs conjugated with nonstructural protein 2 (NS2) gene of Hepatitis C Virus genotype 4a (HCV4a) as a safe and an efficient vaccine delivery system. Gel.NPs were synthesized and characterized (size: 150±2 nm and zeta potential +17.6 mv). NS2 gene was successfully cloned and expressed into E. coli M15 using pQE-30 vector. Antigenicity of the recombinant NS2 protein was confirmed by Western blotting to verify the efficiency of NS2 as a possible vaccine. Then NS2 gene was conjugated to gelatin nanoparticles and a successful conjugation was confirmed by labeling and imaging using Confocal Laser Scanning Microscope (CLSM). Interestingly, the transformation of the conjugated NS2/Gel.NPs complex into E. coli DH5-α was 50% more efficient than transformation with the gene alone. In addition, conjugated NS2/Gel.NPs with ratio 1:100 (w/w) showed higher transformation efficiency into E. coli DH5-α than the other ratios (1:50 and 2:50). Gel.NPs effectively enhanced the gene delivery in bacterial cells without affecting the structure of NS2 gene and could be used as a safe, easy, rapid, cost-effective and non-viral vaccine delivery system for HCV.

Safety and efficacy evaluation of gelatin-based nanoparticles associated with UV filters.

Science.gov (United States)

Oliveira, Camila Areias de; Dario, Michelli Ferrera; Sarruf, Fernanda Daud; Mariz, Inês Fátima Afonso; Velasco, Maria Valéria Robles; Rosado, Catarina; Baby, André Rolim

2016-04-01

The safety and efficacy assessment of nanomaterials is a major concern of industry and academia. These materials, due to their nanoscale size, can have chemical, physical, and biological properties that differ from those of their larger counterparts. The encapsulation of natural ingredients can provide marked improvements in sun protection efficacy. This strategy promotes solubility enhancement of flavonoids and yields an improved active ingredient with innovative physical, physicochemical and functional characteristics. Rutin, a flavonoid, has chemical and functional stability in topical vehicles exerting a synergistic effect in association with ultraviolet (UV) filters. However, the solubility of rutin is a limiting factor. Additionally, this bioactive compound does not have tendency to permeate across the stratum corneum. As an alternative to common synthetic based sunscreens, rutin-entrapped gelatin nanoparticles were designed. The present study investigated the pre-clinical safety of gelatin nanoparticles (GNPs) using an in vitro method and also assessed the clinical safety and efficacy of the association of GNPs with three commonly used chemical UV filters (ethylhexyl dimethyl PABA, ethylhexyl methoxycinnamate and methoxydibenzoylmethane). The non-irritant and adequate safety profile under sun-exposed skin conditions of the nanomaterials and the emulsions qualified the products for clinical efficacy assays. The in vivo results indicated that the GNPs increased the antioxidant protection of the emulsions developed. However, the presence of rutin in the nanosized material did not enhance performance on the SPF test. In conclusion, these findings characterized the nanomaterials as an innovative platform for multifunctional bioactive sunscreens. Copyright © 2015 Elsevier B.V. All rights reserved.

Robust platforms for creating organic-inorganic nanocomposite microspheres: decorating polymer microspheres containing mussel-inspired adhesion layers with inorganic nanoparticles.

Science.gov (United States)

Satoh, H; Saito, Y; Yabu, H

2014-12-07

We describe a method for creating robust and stable core-shell polymer microspheres decorated with inorganic (IO) nanoparticles (NPs) by a self-organization process and heterocoagulation using a mussel-inspired polymer adhesive layer between the IO NPs and the microspheres.

Research progress of siloxane removal from biogas

Directory of Open Access Journals (Sweden)

Gao Ruiling

2017-01-01

Full Text Available Siloxanes in biogas are detrimental to engine, turbine, fuel cell, etc., thus it is necessary to remove siloxanes from biogas before biogas high-value utilization. At present, there are few domestic researches and related reports in view of siloxanes removal from biogas. This paper introduces the property of siloxanes as well as sampling and analysis method, and then presents the research progress of siloxanes removal from biogas. Three commercial technologies overseas are adsorption, absorption and cryogenic condensation. Among them, adsorption on activated carbon is the most widely used method. Other technologies, such as biological removal, catalytic processes, membranes, source controlling, etc. are under exploration and development. At last, this paper summarizes the advantages and disadvantages of siloxanes removal technologies as well as the applicability and analyzes the future research trend and emphasis. This paper could provide a reference in the field of biogas high-value utilization.

Preparation of a durable superhydrophobic membrane by electrospinning poly (vinylidene fluoride) (PVDF) mixed with epoxy-siloxane modified SiO2 nanoparticles: a possible route to superhydrophobic surfaces with low water sliding angle and high water contact angle.

Science.gov (United States)

Wang, Shuai; Li, Yapeng; Fei, Xiaoliang; Sun, Mingda; Zhang, Chaoqun; Li, Yaoxian; Yang, Qingbiao; Hong, Xia

2011-07-15

A durable superhydrophobic surface with low water sliding angle (SA) and high water contact angle (CA) was obtained by electrospinning poly (vinylidene fluoride) (PVDF) which was mixed with epoxy-siloxane modified SiO(2) nanoparticles. To increase the roughness, modified SiO(2) nanoparticles were introduced into PVDF precursor solution. Then in the electrospinning process, nano-sized SiO(2) particles irregularly inlayed (it could also be regard as self-assembly) in the surface of the micro-sized PVDF mini-islands so as to form a dual-scale structure. This structure was responsible for the superhydrophobicity and self-cleaning property. In addition, epoxy-siloxane copolymer was used to modify the surface of SiO(2) nanoparticles so that the SiO(2) nanoparticles could stick to the surface of the micro-sized PVDF mini-islands. Through the underwater immersion test, the SiO(2) nanoparticles cannot be separated from PVDF easily so as to achieve the effect of durability. We chiefly explore the surface wettability and the relationship between the mass ratio of modified SiO(2) nanoparticles/PVDF and the CA, SA of electrospun mat. As the content of modified SiO(2) nanoparticles increased, the value of CA increased, ranging from 145.6° to 161.2°, and the water SA decreased to 2.17°, apparently indicating that the membrane we fabricated has a perfect effect of superhydrophobicity. Copyright © 2011 Elsevier Inc. All rights reserved.

Improved thermal conductivity of Ag decorated carbon nanotubes water based nanofluids

Energy Technology Data Exchange (ETDEWEB)

Farbod, Mansoor, E-mail: farbod_m@scu.ac.ir; Ahangarpour, Ameneh

2016-12-16

The effect of Ag decoration of carbon nanotubes on thermal conductivity enhancement of Ag decorated MWCNTs water based nanofluids has been investigated. The pristine and functionalized MWCNTs were decorated with Ag nanoparticles by mass ratios of 1%, 2% and 4% and used to prepare water based nanofluids with 0.1 vol.%. An enhancement of 1–20.4 percent in thermal conductivity was observed. It was found that the decoration of functionalized MWCNTs can increase the thermal conductivity about 0.16–8.02 percent compared to the undecorated ones. The maximum enhancement of 20.4% was measured for the sample containing 4 wt.% Ag at 40 °C. - Highlights: • MWCNTs were decorated with Ag nanoparticles by the mass ratios of 1, 2 and 4%. • The decorated CNTs were used to prepare water based nanofluids with 0.1 Vol.%. • 1–20.4% increase was observed in thermal conductivity (TC) compared to pure water. • Ag decorated CNTs increased TC of nanofluid up to 8% compared to CNTs nanofluid.

TiO2 Nanorods Decorated with Pd Nanoparticles for Enhanced Liquefied Petroleum Gas Sensing Performance.

Science.gov (United States)

Dhawale, Dattatray S; Gujar, Tanaji P; Lokhande, Chandrakant D

2017-08-15

Development of highly sensitive and selective semiconductor-based metal oxide sensor devices to detect toxic, explosive, flammable, and pollutant gases is still a challenging research topic. In the present work, we systematically enhanced the liquefied petroleum gas (LPG) sensing performance of chemical bath deposited TiO 2 nanorods by decorating Pd nanoparticle catalyst. Surface morphology with elemental mapping, crystal structure, composition and oxidation states, and surface area measurements of pristine TiO 2 and Pd:TiO 2 nanorods was examined by high resolution transmission electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption characterization techniques. LPG sensing performance of pristine TiO 2 and Pd:TiO 2 nanorods was investigated in different LPG concentration and operating temperature ranges. The LPG response of 21% for pristine TiO 2 nanorods is enhanced to 49% after Pd catalyst decoration with reasonably fast response and recovery times. Further, the sensor exhibited long-term stability, which could be due to the strong metal support (Pd:TiO 2 ) interaction and catalytic properties offered by the Pd nanoparticle catalyst. The work described herein demonstrates a general and scalable approach that provides a promising route for rational design of variety of sensor devices for LPG detection.

Visualization of silver-decorated poly (DL-lactide-co-glycolide) nanoparticles and their efficacy against Staphylococcus epidermidis

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Chisato, E-mail: chisato@dpc.agu.ac.jp [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan); Matsubara, Nobuhiro; Akachi, Yuki; Ogawa, Noriko [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan); Kalita, Golap [Department of Frontier Materials, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Asaka, Toru [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Tanemura, Masaki [Department of Frontier Materials, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Kawashima, Yoshiaki; Yamamoto, Hiromitsu [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan)

2017-03-01

Understanding of self-protection activity of the bacteria and interaction with drug substances has significant importance for designing of effective drug delivery system for treatment of biofilm infections. Recently silver nanoparticle has attracted attention as antibacterial substance for drug delivery system because of its high antibacterial activity. Here, efflux of silver nanoparticles obtained from within the prepared silver-decorated poly (DL-lactide-co-glycolide) (Ag PLGA) nanoparticles derived from Staphylococcus epidermidis bacterial cell was successfully visualized using scanning transmission electron microscopy (STEM). We also revealed the interaction between prepared Ag PLGA nanoparticles and the bacterial cells at the nanoscale level using field emission scanning electron microscopy and STEM, after a pretreatment process by an ionic liquid. This finding is significant to understand a fundamental function of S. epidermidis bacterial cells, which is not explored previously. The results suggest that Ag PLGA nanoparticles could demonstrate high efficacy against biofilm infections. - Highlights: • Ag PLGA nanoparticles with high efficacy against biofilm infections were prepared. • Self-protection activity of bacteria against Ag nanoparticles was visualized by STEM. • Antibacterial mechanism of Ag PLGA nanoparticles against biofilm was proposed.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens

International Nuclear Information System (INIS)

Peng, Jian-min; Lin, Jia-cheng; Chen, Zhuo-yu; Wei, Meng-chao; Fu, Yuan-xiang; Lu, Shu-shen; Yu, Dong-sheng; Zhao, Wei

2017-01-01

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs. - Highlights: • This study synthesized R-GNs/Ag composites by a chemical reduction method. • AgNPs were successfully dispersed on reduced graphene nanosheets. • R-GNs/Ag composites showed enhanced antimicrobial activities against oral pathogens compared with plain AgNPs or R-GNs.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens

Energy Technology Data Exchange (ETDEWEB)

Peng, Jian-min; Lin, Jia-cheng; Chen, Zhuo-yu; Wei, Meng-chao [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Fu, Yuan-xiang; Lu, Shu-shen [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Yu, Dong-sheng, E-mail: yudsh@mail.sysu.edu.cn [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Zhao, Wei, E-mail: zhaowei3@mail.sysu.edu.cn [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

2017-02-01

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs. - Highlights: • This study synthesized R-GNs/Ag composites by a chemical reduction method. • AgNPs were successfully dispersed on reduced graphene nanosheets. • R-GNs/Ag composites showed enhanced antimicrobial activities against oral pathogens compared with plain AgNPs or R-GNs.

Intercorrelated Ag{sub 3}PO{sub 4} nanoparticles decorated with graphic carbon nitride: Enhanced stability and photocatalytic activities for water treatment

Energy Technology Data Exchange (ETDEWEB)

Ren, Jia; Chai, Yuanyuan; Liu, Qianqian; Zhang, Lu; Dai, Wei-Lin, E-mail: wldai@fudan.edu.cn

2017-05-01

Highlights: • Ag{sub 3}PO{sub 4} nanoparticles decorated with graphite-like carbon nitride material (g-C{sub 3}N{sub 4}). • Synthesized by a template-free in situ precipitation method. • Excellent (7 times higher) photooxidation ability. • Much more stable than pure Ag{sub 3}PO{sub 4} in the photodegradation process. • Formation of heterojunction between Ag{sub 3}PO{sub 4} and g-C{sub 3}N{sub 4} contributed to the separation efficiency. - Abstract: The method of decorating Ag{sub 3}PO{sub 4} nanoparticles with carbon nitride material (g-C{sub 3}N{sub 4}) is demonstrated as an efficient pathway to remarkably improve the stability and photocatalytic performance of Ag{sub 3}PO{sub 4} nanoparticles which have been widely used in photocatalysis, but limited by the instability. The improved material herein results in the largely enhanced photocatalytic performance for water purification under visible light irradiation, which was nearly 7 times as high as that of pure Ag{sub 3}PO{sub 4}. Meanwhile, the as-obtained materials show the unique stable property, mainly contributed by the protection effect of decorated g-C{sub 3}N{sub 4} sheet. Additionally, the radical trapping experiments revealed that the introduction of g-C{sub 3}N{sub 4} transformed the photocatalytic mechanism to some degree, where ·O{sub 2}{sup −} played a more important role. The tremendous enhancement in catalytic performance may be attributed to the larger surface area, controllable particle size and the synergistic effect between Ag{sub 3}PO{sub 4} and g-C{sub 3}N{sub 4}, promoting the separation efficiency of the photogenerated electron-hole pairs. The decorating system can in principle be broadly put into use for unstable photocatalysts.

Gold-Decorated Supraspheres of Block Copolymer Micelles

Science.gov (United States)

Kim, M. P.; Kang, D. J.; Kannon, A. G.; Jung, D.-W.; Yi, G. R.; Kim, B. J.

2012-02-01

Gold-decorated supraspheres displaying various surface morphologies were prepared by infiltration of gold precursor into polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) supraspheres under acidic condition. The supraspheres were fabricated by emulsifying PS-b-P2VP polymer solution into surfactant solution. Selective swelling of P2VP in the suprasphere by gold precursor under acidic condition resulted in the formation of gold-decorated supraspheres with various surface structures. As evidenced by TEM and SEM images, dot pattern was formed in the case of smaller supraspheres than 800 nm; whereas fingerprint-like pattern was observed in larger supraspheres than 800 nm. Gold nanoparticles were located inside P2VP domains near the surface of prepared supraspheres as confirmed by TEM. The optical property of the supraspheres was characterized using UV-vis absorption spectroscopy and the maximum absorption peak at around 580 nm was observed, which means that gold nanoparticles densely packed into P2VP domain on the suprasphere. Our approach to prepare gold-decorated supraspheres can be extended to other metallic particles such as iron oxide or platinum nanoparticles, and those precursors can be also selectively incorporated into the P2VP domain.

SERS Detection of Penicillin G Using Magnetite Decorated with Gold Nanoparticles

Directory of Open Access Journals (Sweden)

Paula C. Pinheiro

2017-10-01

Full Text Available Sensitive and reliable procedures for detecting vestigial antibiotics are of great relevance for water quality monitoring due to the occurrence of such emergent pollutants in the aquatic environment. As such, we describe here research concerning the use of multifunctional nanomaterials combining magnetic and plasmonic components. These nanomaterials have been prepared by decorating magnetite nanoparticles (MNP with colloidal gold nanoparticles (Au NPs of distinct particle size distributions. Several analytical conditions were investigated in order to optimize the surface enhanced Raman scattering (SERS detection of penicillin G (PG dissolved in water. In particular, the dependence of the SERS signal by using distinct sized Au NPs adsorbed at the MNP was investigated. Additionally, microscopic methods, including Raman confocal microscopy, were employed to characterize the SERS substrates and then to qualitatively detect penicillin G using such substrates. For example, magnetic–plasmonic nanocomposites can be employed for magnetically concentrate analyte molecules and their removal from solution. As a proof of concept, we applied magneto-plasmonic nanosorbents in the removal of aqueous penicillin G and demonstrate the possibility of SERS sensing this antibiotic.

Characterization of carbon nanotubes decorated with NiFe2O4 magnetic nanoparticles as a novel electrochemical sensor: Application for highly selective determination of sotalol using voltammetry

International Nuclear Information System (INIS)

Ensafi, Ali A.; Allafchian, Ali R.; Rezaei, B.; Mohammadzadeh, R.

2013-01-01

A magnetic nano‐composite of multiwall carbon nanotube, decorated with NiFe 2 O 4 nanoparticles, was synthesized with citrate sol–gel method. The multiwall carbon nanotubes decorated with NiFe 2 O 4 nanoparticles (NiFe 2 O 4 –MWCNTs) were characterized with different methods such as Fourier transform infrared spectroscopy (FT‐IR), transmission electron microscopy (TEM), atomic force microscopy (AFM), vibrating sample magnetometer (VSM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The new nano-composite acts as a suitable electrocatalyst for the oxidation of sotalol at a potential of 500 mV at the surface of the modified electrode. Linear sweep voltammetry exhibited two wide linear dynamic ranges of 0.5–1000 μmol L −1 sotalol with a detection limit of 0.09 μmol L −1 . The modified electrode was used as a novel electrochemical sensor for the determination of sotalol in real samples such as pharmaceutical, patient and safe human urine. - Graphical abstract: Multiwall carbon nanotube, decorated with NiFe 2 O 4 nanoparticles, was prepared using citrate sol–gel method. We characterized the new nanoparticles with different spectroscopic and voltammetric methods. The nano sensor was used as a voltammetric sensor for the determination of trace amounts of sotalol at pH 7.0. Highlights: ► We synthesized and prepared new sensor, multiwall carbon nanotubes decorated with NiFe 2 O 4 . ► Several spectroscopic and voltammetric methods were used to study its characteristics. ► The nanoparticles act as suitable electrocatalyst for the oxidation of sotalol. ► Sotalol could be measured as low as 0.09 μmol L −1 using linear sweep voltammetry.

Two-dimensional ZnO ultrathin nanosheets decorated with Au nanoparticles for effective photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Hu, Jin; You, Ning; Yu, Zhe; Zhou, Gang [College of Physics Science and Technology, Yangzhou University, Yangzhou 225002 (China); Xu, Xiaoyong, E-mail: xxy@yzu.edu.cn [College of Physics Science and Technology, Yangzhou University, Yangzhou 225002 (China); State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China)

2016-08-21

Two-dimensional (2D) materials, especially the inorganic 2D nanosheets (NSs), are of particular interest due to their unique structural and electronic properties, which are favorable for photoelectronic applications such as photocatalysis. Here, we design and fabricate the ultrathin 2D ZnO NSs decorated with Au nanoparticles (AuNPs), though molecular modelling 2D hydrothermal growth and followed by surface modification are used as an effective photocatalyst for photocatalytic organic dye degradation and hydrogen production. The ultrathin 2D nature enables ultrahigh atom ratio near surface to proliferate the active sites, and the Au plasmon plays a promoting role in the visible-light absorption and photogenerated charge separation, thus integrating the synergistic benefits to boost the redox reactions at catalyst/electrolyte interface. The AuNPs-decorated ZnO NSs yield the impressive photocatalytic activities such as the dye degradation rate constant of 7.69 × 10{sup −2} min{sup −1} and the hydrogen production rate of 350 μmol h{sup −1} g{sup −1}.

Nanoparticle decoration with surfactants: Molecular interactions, assembly, and applications

Science.gov (United States)

Heinz, Hendrik; Pramanik, Chandrani; Heinz, Ozge; Ding, Yifu; Mishra, Ratan K.; Marchon, Delphine; Flatt, Robert J.; Estrela-Lopis, Irina; Llop, Jordi; Moya, Sergio; Ziolo, Ronald F.

2017-02-01

Nanostructures of diverse chemical nature are used as biomarkers, therapeutics, catalysts, and structural reinforcements. The decoration with surfactants has a long history and is essential to introduce specific functions. The definition of surfactants in this review is very broad, following its lexical meaning ;surface active agents;, and therefore includes traditional alkyl modifiers, biological ligands, polymers, and other surface active molecules. The review systematically covers covalent and non-covalent interactions of such surfactants with various types of nanomaterials, including metals, oxides, layered materials, and polymers as well as their applications. The major themes are (i) molecular recognition and noncovalent assembly mechanisms of surfactants on the nanoparticle and nanocrystal surfaces, (ii) covalent grafting techniques and multi-step surface modification, (iii) dispersion properties and surface reactions, (iv) the use of surfactants to influence crystal growth, as well as (v) the incorporation of biorecognition and other material-targeting functionality. For the diverse materials classes, similarities and differences in surfactant assembly, function, as well as materials performance in specific applications are described in a comparative way. Major factors that lead to differentiation are the surface energy, surface chemistry and pH sensitivity, as well as the degree of surface regularity and defects in the nanoparticle cores and in the surfactant shell. The review covers a broad range of surface modifications and applications in biological recognition and therapeutics, sensors, nanomaterials for catalysis, energy conversion and storage, the dispersion properties of nanoparticles in structural composites and cement, as well as purification systems and classical detergents. Design principles for surfactants to optimize the performance of specific nanostructures are discussed. The review concludes with challenges and opportunities.

X-ray diffraction on nanoparticles chromium and nickel oxides obtained by gelatin using synchrotron radiation

International Nuclear Information System (INIS)

Menezes, Alan Silva de; Medeiros, Angela Maria de Lemos; Miranda, Marcus Aurelio Ribeiro; Almeida, Juliana Marcela Abraao; Remedios, Claudio Marcio Rocha; Silva, Lindomar R.D. da; Gouveia, S.T.; Sasaki, Jose Marcos; Jardim, P.M.

2003-01-01

Full text: Cr 2 O 3 nanoparticles has many applications like green pigments, wear resistance, and coating materials for thermal protection. Several methods to produce chromium oxide nanoparticles have already been studied, gas condensation, laser induced pyrolysis, microwave plasma, sol-gel and gamma radiation methods. Many applications for this kind of material can be provide concerning the particle size. For instance, particle size approximately of 200 nm are preferable as pigment due to its opacity and below 50 nm can be used as transparent pigment. In this work we have demonstrated that chromium and nickel oxide nanoparticles can be prepared by gelatin method. X-Ray diffraction (XRD) show that mean particle size for chromium oxide of 15-150 nm and nickel oxide of 90 nm were obtained for several temperature of sintering. The X-Ray powder diffraction pattern were performed using Synchrotron Radiation X-Ray source at XRD1 beamline in National Laboratory of Light Synchrotron (LNLS). (author)

Experimental and theoretical study on field emission properties of zinc oxide nanoparticles decorated carbon nanotubes

Science.gov (United States)

Li, Xin; Zhou, Wei-Man; Liu, Wei-Hua; Wang, Xiao-Li

2015-05-01

Field emission properties of zinc oxide (ZnO) nanoparticles (NPs) decorated carbon nanotubes (CNTs) are investigated experimentally and theoretically. CNTs are in situ decorated with ZnO NPs during the growth process by chemical vapor deposition using a carbon source from the iron phthalocyanine pyrolysis. The experimental field emission test shows that the ZnO NP decoration significantly improves the emission current from 50 μA to 275 μA at 550 V and the reduced threshold voltage from 450 V to 350 V. The field emission mechanism of ZnO NPs on CNTs is theoretically studied by the density functional theory (DFT) combined with the Penn-Plummer method. The ZnO NPs reconstruct the ZnO-CNT structure and pull down the surface barrier of the entire emitter system to 0.49 eV so as to reduce the threshold electric field. The simulation results suggest that the presence of ZnO NPs would increase the LDOS near the Fermi level and increase the emission current. The calculation results are consistent with the experiment results. Project supported by the National Natural Science Foundation of China (Grant Nos. 91123018, 61172040, and 61172041) and the Natural Science Foundation of Shaanxi Province, China (Grant No. 2014JM7277).

Decoration of PbS nanoparticles on Al-doped ZnO nanorod array thin film with hydrogen treatment as a photoelectrode for solar water splitting

Energy Technology Data Exchange (ETDEWEB)

Hsu, Chih-Hsiung; Chen, Chao-Hong [Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Chen, Dong-Hwang, E-mail: chendh@mail.ncku.edu.tw [Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

2013-03-25

Highlights: ► AZO nanorod array thin film is used as a photoanode for solar water splitting. ► Hydrogen treatment and sensitization by PbS nanoparticles enhance photocurrent. ► A novel ITO/FTO-free composite photoelectrode is developed. ► The pre-fabrication and use of an extra TCO thin film substrate is unnecessary. -- Abstract: Al-doped ZnO (AZO) nanorod arrays thin film with hydrogen treatment is directly used as a photoelectrode for solar water splitting without an extra transparent conducting oxide (TCO) thin film because it possesses the functions of TCO thin film and photoactive 1-dimensional nanostructured semiconductor simultaneously. To enhance the absorption in the visible region, PbS nanoparticles decorated the AZO nanorods via successive ionic layer adsorption and reaction route. The PbS nanoparticles have a face-centered cubic structure and their decoration does not destroy the 1-dimensional morphology of AZO nanorod arrays. With increasing the cycle number of PbS nanoparticles decoration, the grain size and loading of PbS nanoparticles become larger gradually which leads to lower energy bandgap and stronger absorption. A maximum photocurrent density of 1.65 mW cm{sup −2} is obtained when the cycle number is 20, which is much higher than those without PbS nanoparticles sensitization or hydrogen treatment. This demonstrates that the AZO nanorod array thin film with hydrogen treatment can be directly used as a photoelectrode without an extra TCO thin film. Because the use of expensive metals can be avoided and the pre-fabrication of TCO thin film substrate is necessary no more, the fabrication of such a composite photoelectrode becomes simple and low-cost. So, it has great potentials in solar water splitting after sensitization by quantum dots capable of visible light absorption.

Synthesis of Pd-coated FeCo@Fe/C core-shell nanoparticles: microwave-induced ‘top-down’ nanostructuring and decoration

CSIR Research Space (South Africa)

Fashedemi, OO

2013-01-01

Full Text Available We report a novel microwave-induced fast and efficient synthesis of sub-10 nm sized palladium-decorated FeCo@Fe core–shell nanoparticles (ca. 3–7 nm) from a large-sized FeCo@Fe (0.21–1.5 µm) precursor, suggesting ‘top-down’ nanosizing. The high...

Acetone gas-sensing properties of multiple-networked Pd-decorated Bi_2O_3 nanorod sensors

International Nuclear Information System (INIS)

Park, Sung Hoon; Kim, Soo Hyun; Lee, Sang Min; Lee, Chong Mu

2015-01-01

This study examined the sensing properties of Bi_2O_3 nanorods decorated with Pd nanoparticles. Pd-decorated β-Bi_2O_3 nanorods were prepared by immersing the Bi_2O_3 nanorods in ethanol/(50 mM)PdCl_2 solution followed by UV irradiation and annealing. The Bi_2O_3 nanorods decorated with Pd nanoparticles showed faster and stronger response to acetone gas than the pristine Bi_2O_3 nanorods. Interestingly, the difference in response time between the Pd-decorated Bi_2O_3 nanorod sensor and pristine Bi_2O_3 nanorod sensor increased with increasing the acetone gas concentration. In contrast, the difference in recovery time between the two nanorod sensors decreased with increasing the acetone gas concentration. This difference can be explained using the chemical mechanism. The underlying mechanism for the enhanced response of the Bi_2O_3 nanorods decorated with Pd nanoparticles to acetone gas is also discussed

Nickel nanoparticle decorated graphene for highly selective isolation of polyhistidine-tagged proteins

Science.gov (United States)

Liu, Jia-Wei; Yang, Ting; Ma, Lin-Yu; Chen, Xu-Wei; Wang, Jian-Hua

2013-12-01

Nickel nanoparticle decorated graphene (GP-Ni) is prepared by one-pot hydrothermal reduction of graphene oxide and nickel cations by hydrazine hydrate in the presence of poly(sodium-p-styrenesulfonate) (PSS). The GP-Ni hybrid is characterized by XRD, TEM, SEM, XPS, Raman and FT-IR spectra, demonstrating the formation of poly-dispersed nickel nanoparticles with an average size of 83 nm attached on the surface of graphene sheets. The GP-Ni hybrid exhibits ferromagnetic behavior with a magnetization saturation of 31.1 emu g-1 at 10 000 Oersted (Oe). The GP-Ni also possesses favorable stability in aqueous medium and rapid magnetic response to an external magnetic field. These make it a novel magnetic adsorbent for the separation/isolation of His6-tagged recombinant proteins from a complex sample matrix (cell lysate). The targeted protein species is captured onto the surface of the GP-Ni hybrid via specific metal affinity force between polyhistidine groups and nickel nanoparticles. The SDS-PAGE assay indicates highly selective separation of His6-tagged Smt A from cell lysate. The GP-Ni hybrid displays favorable performance on the separation/isolation of His6-tagged recombinant proteins with respect to the commercial NTA-Ni2+ column.

nanoparticles-decorated activated carbon nanocomposite based ...

Indian Academy of Sciences (India)

T K APARNA

2018-02-07

Feb 7, 2018 ... oxide nanohexagon-reduced graphene oxide nanocom- posite39 was reported ..... istic vibrations of the chemical bonds were inferred. The electrochemical .... hybrid decorated with molybdenum disulfide flowers. Microchim.

Siloxanes in silicone products intended for food contact

DEFF Research Database (Denmark)

Cederberg, Tommy Licht; Jensen, Lisbeth Krüger

oligomers which might migrate to the food when the product is being used. DTU has proposed two action limits for low molecular weight siloxanes in food contact materials. For the sum of cyclic siloxanes D3 to D8 the limits are 12 mg/kg food for adults and 2 mg/kg food for children. For the sum of cyclic...... siloxanes D3 to D13 and linear siloxanes L3-L13 the limit is 60 mg/kg food. In 49 samples of silicone products intended for food contact from the Norwegian markets content of siloxanes has been measured. Coated paper for baking constituted 8 of the samples and in none of those samples siloxanes were found......Silicone is used in food contact materials due to its excellent physical and chemical properties. It is thermostable and flexible and is used in bakeware and kitchen utensils. Silicone is also used to coat paper to make it water and fat resistant. There is no specific regulation in EU which covers...

Enhanced ferroelectric photoelectrochemical properties of polycrystalline BiFeO{sub 3} film by decorating with Ag nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Liu, Qing; Shen, Mingrong; Fang, Liang, E-mail: lfang@suda.edu.cn [College of Physics, Optoelectronics and Energy and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006 (China); Zhou, Yang; You, Lu; Wang, Junling [School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore 639798 (Singapore)

2016-01-11

Polycrystalline BiFeO{sub 3} (BFO) films are fabricated on Pt/Ti/SiO{sub 2}/Si(100) substrate as photoelectrode using sol-gel method. The microstructure, optical, and photoelectrochemical (PEC) properties of the films are characterized and optimized by controlling the film thickness. Moreover, the PEC properties of the BFO films are dependent on ferroelectric polarization, which is mainly ascribed to the modulation of band structure at the BFO/electrolyte interface by the polarization. Further enhancement of PEC properties is obtained by decorating the samples with appropriate amounts of Ag nanoparticles, which is attributed to the reduced electron-hole recombination, and localized surface plasmon resonance effect of Ag nanoparticles.

Dye-sensitized solar cells based on nanoparticle-decorated ZnO/TiO2 core/shell nanorod arrays

International Nuclear Information System (INIS)

Wang Meili; Huang Changgang; Cao Yongge; Deng Zhonghua; Liu Yuan; Huang Zhi; Huang Jiquan; Huang Qiufeng; Guo Wang; Liang Jingkui; Yu Qingjiang

2009-01-01

Nanoparticles (NPs) decorated ZnO/TiO 2 core/shell nanorod arrays were fabricated on transparent conductive glass substrates by sequential plasma deposition and post-annealing processes for dye-sensitized solar cells (DSSCs) applications. The NPs decorated ZnO/TiO 2 nanorods were composed of single-crystalline ZnO nanorods, homogeneously coated thin TiO 2 shells and entirely covered anatase TiO 2 NPs. The photocurrent density of the composite electrode was largely enhanced due to the enlarged surface area, the dark current was suppressed and the open-circuit voltage was increased because of the energy barrier formed at the interface between the ZnO core and the TiO 2 shell. The increased photocurrent and open-circuit voltage led to an improvement of twice the energy conversion efficiency.

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)

Cross-linked gelatin/nanoparticles composite coating on micro-arc oxidation film for corrosion and drug release

Energy Technology Data Exchange (ETDEWEB)

Xu Xinhua, E-mail: xhxu_tju@eyou.com [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Lu Ping; Guo Meiqing; Fang Mingzhong [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

2010-02-01

A composite coating which could control drug release and biocorrosion of magnesium alloy stent materials WE42 was prepared. This composite coating was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy, WE42, by mixing different degrees of cross-linked gelatin with well-dispersed poly(DL-lactide-co-glycolide) (PLGA) nanoparticles. The PLGA nanoparticles were prepared by emulsion solvent evaporation/extraction technique. Nano ZS laser diffraction particle size analyzer detected that the size of the nanoparticles to be 150-300 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to analyze the morphology of the nanoparticles and the composite coating. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of the composite coating. Drug release was determined by ultraviolet-visible (UV-vis) spectrophotometer. The corrosion resistance of the composite coating was improved by preventing the corrosive ions from diffusing to the MAO films. The drug release rate of paclitaxel (PTX) exhibited a nearly linear sustained-release profile with no significant burst releases.

Cross-linked gelatin/nanoparticles composite coating on micro-arc oxidation film for corrosion and drug release

International Nuclear Information System (INIS)

Xu Xinhua; Lu Ping; Guo Meiqing; Fang Mingzhong

2010-01-01

A composite coating which could control drug release and biocorrosion of magnesium alloy stent materials WE42 was prepared. This composite coating was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy, WE42, by mixing different degrees of cross-linked gelatin with well-dispersed poly(DL-lactide-co-glycolide) (PLGA) nanoparticles. The PLGA nanoparticles were prepared by emulsion solvent evaporation/extraction technique. Nano ZS laser diffraction particle size analyzer detected that the size of the nanoparticles to be 150-300 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to analyze the morphology of the nanoparticles and the composite coating. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of the composite coating. Drug release was determined by ultraviolet-visible (UV-vis) spectrophotometer. The corrosion resistance of the composite coating was improved by preventing the corrosive ions from diffusing to the MAO films. The drug release rate of paclitaxel (PTX) exhibited a nearly linear sustained-release profile with no significant burst releases.

Cross-linked gelatin/nanoparticles composite coating on micro-arc oxidation film for corrosion and drug release

Science.gov (United States)

Xu, Xinhua; Lu, Ping; Guo, Meiqing; Fang, Mingzhong

2010-02-01

A composite coating which could control drug release and biocorrosion of magnesium alloy stent materials WE42 was prepared. This composite coating was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy, WE42, by mixing different degrees of cross-linked gelatin with well-dispersed poly( DL-lactide-co-glycolide) (PLGA) nanoparticles. The PLGA nanoparticles were prepared by emulsion solvent evaporation/extraction technique. Nano ZS laser diffraction particle size analyzer detected that the size of the nanoparticles to be 150-300 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to analyze the morphology of the nanoparticles and the composite coating. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of the composite coating. Drug release was determined by ultraviolet-visible (UV-vis) spectrophotometer. The corrosion resistance of the composite coating was improved by preventing the corrosive ions from diffusing to the MAO films. The drug release rate of paclitaxel (PTX) exhibited a nearly linear sustained-release profile with no significant burst releases.

Gold nanoparticles: sonocatalytic synthesis using ethanolic extract of Andrographis paniculata and functionalization with polycaprolactone-gelatin composites

Science.gov (United States)

Babu, Punuri Jayasekhar; Saranya, Sibyala; Sharma, Pragya; Tamuli, Ranjan; Bora, Utpal

2012-09-01

Gold nanoparticles (AuNPs) were synthesized by sonication using ethanolic leaf extract of Andrographis paniculata. We investigated the optimum parameters for AuNP synthesis and functionalization with polycaprolactone-gelatin (PCL-GL) composites. The AuNPs were characterized with various biophysical techniques such as TEM, XRD, FT-IR and EDX spectroscopy. TEM images showed that nanoparticles were spherical in shape with a size range from 5 to 75 nm. EDX analysis revealed the presence of molecular oxygen and carbon on the surface of AuNPs. The synthesized AuNPs were tested for their effect on HeLa (human cervical cancer) and MCF-7 (human breast cancer) cell lines and found to be nontoxic and biocompatible, which are potential carriers for hydrophobic drugs.

Improving g-C{sub 3}N{sub 4} photocatalysis for NO{sub x} removal by Ag nanoparticles decoration

Energy Technology Data Exchange (ETDEWEB)

Sun, Yanjuan [Air Environmental Modelling and Pollution Controlling Key Laboratory of Sichuan Higher Education Institutes, College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225 (China); Chongqing Key Laboratory of Catalysis and Functional Organic Molecules, College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing 400067 (China); Xiong, Ting; Ni, Zilin [Chongqing Key Laboratory of Catalysis and Functional Organic Molecules, College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing 400067 (China); Liu, Jie [Air Environmental Modelling and Pollution Controlling Key Laboratory of Sichuan Higher Education Institutes, College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225 (China); Dong, Fan, E-mail: dfctbu@126.com [Air Environmental Modelling and Pollution Controlling Key Laboratory of Sichuan Higher Education Institutes, College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225 (China); Chongqing Key Laboratory of Catalysis and Functional Organic Molecules, College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing 400067 (China); Zhang, Wei, E-mail: andyzhangwei@163.com [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China); Ho, Wing-Kei [Department of Science and Environmental Studies, The Centre for Education in Environmental Sustainability, The Hong Kong Institute of Education, Hong Kong (China)

2015-12-15

Graphical abstract: Ag/g-C{sub 3}N{sub 4} nanocomposites were prepared via a facile method for enhanced photocatalytic NO{sub x} removal due to surface plasmon resonance of Ag. - Highlights: • The Ag/g-C{sub 3}N{sub 4} nanocomposites were prepared using urea as the precursor. • The Ag/g-C{sub 3}N{sub 4} nanocomposites were applied in removal of NO{sub x} in air. • The Ag nanoparticles enhanced the photocatalytic activity of g-C{sub 3}N{sub 4}. • The surface plasmon resonance of Ag played a key role in photocatalysis. - Abstract: In order to overcome the intrinsic drawback of pristine g-C{sub 3}N{sub 4}, we prepared g-C{sub 3}N{sub 4} nanosheets with enhanced photocatalytic performance by Ag nanoparticles decoration using urea as the precursor. It was revealed that the monodispersed Ag nanoparticles were deposited on the surface of g-C{sub 3}N{sub 4} nanosheets. The Ag/g-C{sub 3}N{sub 4} nanocomposites were applied in removal of NO{sub x} in air under visible light irradiation. The results showed that the decoration of Ag nanoparticles not only enhanced the photocatalytic activity of g-C{sub 3}N{sub 4} nanosheets, but also benefited the oxidation of NO to final products. The increased visible light absorption arising from the surface plasmon resonance of Ag and improved separation and transfer of photoinduced carriers over Ag/g-C{sub 3}N{sub 4} composites were demonstrated by the UV–vis diffuse reflectance spectra and photoluminescence spectra, respectively. It was therefore proposed that the enhanced photocatalytic activity of Ag/g-C{sub 3}N{sub 4} composites could be attributed to the extended light response range and enhanced charge separation due to the introduction of Ag nanoparticles.

Ultra-low Pt decorated PdFe Alloy Nanoparticles for Formic Acid Electro-oxidation

International Nuclear Information System (INIS)

Zhou, Yawei; Du, Chunyu; Han, Guokang; Gao, Yunzhi; Yin, Geping

2016-01-01

Highlights: • A cost-efficient way is used to prepare transition-noble metal alloy nanoparticles. • The Pd 50 Fe 50 /C catalyst shows excellent activity for formic acid oxidation (FAO). • Much activity enhancement of FAO is acquired by ultra-low Pt decorated Pd 50 Fe 50 . • A synergistic mechanism between Pt clusters and PdFe is proposed during the FAO. - Abstract: Palladium (Pd), has demonstrated promising electro-catalytic activity for formic acid oxidation, but suffers from extremely low abundance. Recently alloying with a transition metal has been considered as an effective approach to reducing the loading of Pd and enhancing the activity of Pd-based catalysts simultaneously. Herein, carbon supported PdFe nanoparticles (NPs) are synthesized at room temperature by using sodium borohydride as reducing agent and potassium ferrocyanide as Fe precursor. The Pd 50 Fe 50 alloy sample annealed at 900 °C for 1 h shows the best catalytic activity among Pd x Fe 1-x (x = 0.2, 0.4, 0.5, 0.6, and 0.8) towards formic acid oxidation. To further improve both catalytic activity and stability, the ultra-low Pt (0.09 wt %) decorated Pd 50 Fe 50 NPs (PtPd/PdFe) are prepared via the galvanic replacement reaction. Compared with Pd 50 Fe 50 /C, the PtPd/PdFe/C Exhibits 1.52 times higher catalytic activity and lower onset potential (−0.12 V). The significant enhancements of formic acid oxidation can be attributed to the accelerated dehydrogenation reaction of formic acid by Pt atomic clusters. Moreover, the PtPd/PdFe/C also demonstrates better tolerance to poisons during formic acid oxidation.

Lycopene loaded gelatin nanoparticles induces internucleosmal DNA fragmentation and apoptosis in human breast adenocarcinoma cells

Science.gov (United States)

Preetha, K. Mary Anne; Devasena, T.

2018-06-01

The complex disease, cancer is caused by genetic uncertainty and various molecular alterations. Due to the present ineffective diagnostic and prognostic classifications, the complete heterogeneity of a tumor is not revealed which in turn affects the selection of suitable treatment and patient outcome. Cancer nanotechnology is an emerging interdisciplinary research field that covers important aspects of chemistry, engineering, biology and medicine, leading to the advancement of cancer diagnosis and treatment. Hence the main aim of this study is to develop lycopene loaded gelatin nanoparticles and evaluate its in vitro anticancer activity using breast adenocarcinoma cells.

Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

KAUST Repository

Zhong, Bo

2017-06-02

We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

KAUST Repository

Zhong, Bo; Wang, Chaojun; Yu, Yuanlie; Xia, Long; Wen, Guangwu

2017-01-01

We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

A novel non-enzymatic H2O2 sensor based on polypyrrole nanofibers–silver nanoparticles decorated reduced graphene oxide nano composites

International Nuclear Information System (INIS)

Moozarm Nia, Pooria; Lorestani, Farnaz; Meng, Woi Pei; Alias, Y.

2015-01-01

Graphical abstract: - Highlights: • Decorating silver nanoparticles on the surface of graphene oxide nanocomposites. • Using and comparing two different electrochemical methods for reducing graphene oxide. • Investigating the effect of cyclic voltammetry and amperometry on electropolymerization of polypyrrole nanofibers. • The senor shows superior performances (LOD, LOQ, selectivity, repeatability, reproducibility and stability) towards H 2 O 2 . - Abstract: Graphene oxide (GO) decorated with silver nanoparticles (AgNPs), was electrochemically reduced on glassy carbon electrode (GCE) by an amperometry method (AMP-AgNPs-rGO/GCE). Then, Pyrrole was electropolymerized on the surface of the modified electrode through amperometry process in order to obtain nanofibers of polypyrrole (AMP-PpyNFs-AgNPs-rGO). Fourier-transform infrared transmission spectroscopy and X-ray diffraction approved that during the amperometry process, the GO and Ppy nanofibers were reduced and polymerized respectively and the silver nanoparticles were formed. Field emission scanning electron microscope images indicated that the silver nanoparticles were homogeneously distributed on the rGO surface with a narrow nano size distribution and polypyrrole synthesized in the form of nanofibers with diameter around 100 nm. The first linear section was in the range of 0.1–5 mM with a limit of detection of 1.099 and the second linear section raised to 90 mM with a correlation factor of 0.085 (S/N of 3)

Catalytic Activity of Silicon Nanowires Decorated with Gold and Copper Nanoparticles Deposited by Pulsed Laser Ablation

Directory of Open Access Journals (Sweden)

Michele Casiello

2018-01-01

Full Text Available Silicon nanowires (SiNWs decorated by pulsed laser ablation with gold or copper nanoparticles (labeled as AuNPs@SiNWs and CuNPs@SiNWs were investigated for their catalytic properties. Results demonstrated high catalytic performances in the Caryl–N couplings and subsequent carbonylations for gold and copper catalysts, respectively, that have no precedents in the literature. The excellent activity, attested by the very high turn over number (TON values, was due both to the uniform coverage along the NW length and to the absence of the chemical shell surrounding the metal nanoparticles (MeNPs. A high recyclability was also observed and can be ascribed to the strong covalent interaction at the Me–Si interface by virtue of metal “silicides” formation.

Synthesis of block copolymers of methyl siloxane, phenyl siloxane, vinyl siloxane, etc

International Nuclear Information System (INIS)

Ibemesi, J.A.; Meier, D.J.

1979-01-01

Synthesis of homo poly(dimethylsiloxane) PDMS, homo poly(diphenylsiloxane PDPS, and di- and tri- block copolymers of PDMS and PDPS have been carried out by anionic living polymerization, using the following reagents: hexamethylcyclotrisiloxane, HMTS and hexaphenylcyclotrisiloxane, HPTS (monomers), n-BuLi and dilithium diphenyldisilanolate, DLS (initiators), DMSO and THF (promoters) and Toluene (solvent). Lithium based catalysts are used in order to minimize siloxane rearrangement (equilibration) reactions

Using Gelatin Nanoparticle Mediated Intranasal Delivery of Neuropeptide Substance P to Enhance Neuro-Recovery in Hemiparkinsonian Rats.

Directory of Open Access Journals (Sweden)

Ying-Zheng Zhao

Full Text Available Intranasal administration of phospholipid-based gelatin nanoparticles (GNP was prepared to investigate the neuro-recovery effects of neuropeptide Substance P (SP on hemiparkinsonian rats.The SP-loaded gelatin nanoparticles (SP-GNP were prepared by a water-in-water emulsion method and possessed high stability, encapsulating efficiency and loading capacity. PC-12 cells were used to examine the growth enhancement of SP-GNP in vitro by MTT assays and flow cytometry (FCM. The therapeutic effects of SP-GNP on 6-hydroxydopamine (6-OHDA induced hemiparkinsonian rats were assessed by quantifying rotational behavior and the levels of tyrosine hydroxylase (TH, phosphorylated c-Jun protein (p-c-Jun and Caspase-3 (Cas-3 expressed in substantia nigra (SN region of hemiparkinsonian rats.PC-12 cells under SP-GNP treatment showed better cell viability and lower degree of apoptosis than those under SP solution treatment. Hemiparkinsonian rats under intranasal SP-GNP administration demonstrated better behavioral improvement, higher level of TH in SN along with much lower extent of p-c-Jun and Cas-3 than those under intranasal SP solution administration and intravenous SP-GNP administration.With the advantages of GNP and nose-to-brain pathway, SP can be effectively delivered into the damaged SN region and exhibit its neuro-recovery function through the inhibition on JNK pathway and dopaminergic neuron apoptosis.

Platinum nanoparticles decorated dendrite-like gold nanostructure on glassy carbon electrodes for enhancing electrocatalysis performance to glucose oxidation

Energy Technology Data Exchange (ETDEWEB)

Jia, Hongmei [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); Chang, Gang, E-mail: changgang@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); Lei, Ming [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); He, Hanping [College of Chemistry and Chemical Engineer, Hubei University, Youyi Road 368, Wuchang, Wuhan, Hubei 430062 (China); Liu, Xiong; Shu, Honghui; Xia, Tiantian; Su, Jie [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); He, Yunbin, E-mail: ybhe@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China)

2016-10-30

Highlights: • Pt/DGNs/GC composites were obtained via a clean and facile method without any templates, surfactants, or stabilizers. • Controlling chemical reduction deposition time, the amount of platinum nanoparticles on Au surface could be regulated, which further tuned electrocatalytic properties toward glucose oxidation. • The obtained Pt/DGNs/GC composites with high electrochemical active surface area (ECSA) show superior electrocatalytic activity to glucose. • The sensor based on Pt/DGNs/GC exhibited excellent sensitivity, selectivity and stability for nonenzymatic glucose detection. - Abstract: Platinum nanoparticles decorated dendrite-like gold nanostructure, bimetal composite materials on glassy carbon electrode (Pt/DGNs/GC) for enhancing electrocatalysis to glucose oxidation was designed and successfully fabricated by a facile two-step deposition method without any templates, surfactants, or stabilizers. Dendrite-like gold nanostructure was firstly deposited on the GC electrode via the potentiostatic method, and then platinum nanoparticles were decorated on the surface of gold substrate through chemical reduction deposition. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) were applied to characterize the evolution of morphology and structure of the as-prepared Pt/DGNs/GC. Based on electrochemical measurements such as cyclic voltammetry, linear voltammetry and chronoamperometry, Pt/DGNs/GC exhibited significantly enhanced electrocatalytic performance to glucose oxidation compared those of pure dendrite-like Au nanoparticles in our previous report. Controlling chemical reduction deposition time, the amount of platinum nanoparticles on Au surface could be regulated, which further tuned electrocatalytic properties toward glucose oxidation. The dendrite-like gold surface partially covered by platinum nanoparticles dramatically enhanced the electrocatalytic performance for the

Hydrogen peroxide sensor: Uniformly decorated silver nanoparticles on polypyrrole for wide detection range

Science.gov (United States)

Nia, Pooria Moozarm; Meng, Woi Pei; Alias, Y.

2015-12-01

Electrochemically synthesized polypyrrole (PPy) decorated with silver nanoparticles (AgNPs) was prepared and used as a nonenzymatic sensor for hydrogen peroxide (H2O2) detection. Polypyrrole was fabricated through electrodeposition, while silver nanoparticles were deposited on polypyrrole by the same technique. The field emission scanning electron microscopy (FESEM) images showed that the electrodeposited AgNPs were aligned along the PPy uniformly and the mean particle size of AgNPs is around 25 nm. The electrocatalytic activity of AgNPs-PPy-GCE toward H2O2 was studied using chronoamperometry and cyclic voltammetry. The first linear section was in the range of 0.1-5 mM with a limit of detection of 0.115 μmol l-1 and the second linear section was raised to 120 mM with a correlation factor of 0.256 μmol l-1 (S/N of 3). Moreover, the sensor presented excellent stability, selectivity, repeatability and reproducibility. These excellent performances make AgNPs-PPy/GCE an ideal nonenzymatic H2O2 sensor.

Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene

Science.gov (United States)

Hazarika, Ankita; Deka, Biplab K.; Kim, DoYoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

2017-01-01

We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90–100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene. PMID:28074877

Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene.

Science.gov (United States)

Hazarika, Ankita; Deka, Biplab K; Kim, DoYoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

2017-01-11

We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90-100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene.

Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene

Science.gov (United States)

Hazarika, Ankita; Deka, Biplab K.; Kim, Doyoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

2017-01-01

We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90-100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene.

Characterization of film-forming solutions and films incorporating free and nanoencapsulated tea polyphenol prepared by gelatins with different Bloom values

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Gelatin film-forming solutions and their films incorporating tea polyphenol (TP) and chitosan nanoparticles (CSNs) were prepared from gelatins with different Bloom values (100, 150 and 225). Blank gelatin film-forming solutions and films were prepared as controls. Gelatins with higher Bloom values h...

Influence of Mg doping on ZnO nanoparticles decorated on graphene oxide (GO) crumpled paper like sheet and its high photo catalytic performance under sunlight

Science.gov (United States)

Labhane, P. K.; Sonawane, S. H.; Sonawane, G. H.; Patil, S. P.; Huse, V. R.

2018-03-01

Mg doped ZnO nanoparticles decorated on graphene oxide (GO) sheets were synthesized by a wet impregnation method. The effect of Mg doping on ZnO and ZnO-GO composite has been evaluated by using x-ray diffraction (XRD), Williamson-Hall Plot (Wsbnd H Plot), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDX). The physical parameters of as-prepared samples were estimated by XRD data. FESEM and HR-TEM images showed the uniform distribution of nanoparticles on GO crumpled paper like sheet. Solar light photocatalytic activities of samples were evaluated spectrophotometrically by the degradation of p-nitrophenol (PNP) and indigo carmine (IC) solution. Mgsbnd ZnO decorated on GO sheets exhibit excellent catalytic efficiency compared to all other prepared samples under identical conditions, degrading PNP and IC nearly 99% within 60 min under sunlight. The effective degradation by Mgsbnd ZnO decorated on GO sheet would be due to extended solar light absorption, enhanced adsorptivity on the composite catalyst surface and efficient charge separation of photo-induced electrons. Finally, plausible mechanism was suggested with the help of scavengers study.

Enzyme decorated drug carriers: Targeted swords to cleave and overcome the mucus barrier.

Science.gov (United States)

Menzel, Claudia; Bernkop-Schnürch, Andreas

2018-01-15

The use of mucus permeating drug carrier systems being able to overcome the mucus barrier can lead to a remarkable enhancement in bioavailability. One promising approach is the design of mucolytic enzyme decorated carrier systems (MECS). These systems include micro- and nanoparticles as well as self-emulsifying drug delivery systems (SEDDS) decorated with mucin cleaving enzymes such as papain (PAP) or bromelain (BRO). MECS are able to cross the mucus barrier in a comparatively efficient manner by cleaving mucus substructures in front of them on their way to the epithelium. Thereby these enzymes hydrolyze peptide bonds of mucus glycoproteins forming tiny holes or passages through the mucus. In various in vitro and in vivo studies MECS proved to be superior in their mucus permeating properties over nanocarriers without enzyme decoration. PAP decorated nanoparticles, for instance, remained 3h after oral administration to an even 2.5-fold higher extend in rat small intestine than the corresponding undecorated nanoparticles permeating the intestinal mucus gel layer to a much lower degree. As MECS break up the mucus network only locally without destroying its overall protective barrier function, even long term treatments with such systems seem feasible. Within this review article we address different drug carrier systems decorated with various types of enzymes, their particular pros and cons and potential applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of novel cycloaliphatic siloxanes for thermal and UV-curable applications

Science.gov (United States)

Chakraborty, Ruby

Siloxanes have been extensively used as additives to modulate surface properties such as surface tension, hydrophobicity/hydrophobicity, and adhesion, etc. Although, polydimethyl -siloxane and polydiphenylsiloxane are the most commonly used siloxanes, the properties are at extremes in terms of glass transition temperature and flexibility. It is proposed that the ability to control the properties in between the these extremes can be provided by cycloaliphatic substitutions at the siloxane backbone. It is expected that this substitution might work due to the intermediate backbone rigidity. In order to achieve the above objectives, a synthetic route was developed to prepare cycloaliphatic (cyclopentane and cyclohexane) silane monomers followed by subsequent polymerization and functionalizations to obtain glycidyl epoxy, aliphatic amine and methacrylate telechelic siloxanes. The siloxanes were either thermally or UV-cured depending on end functionalizations. Chemical characterization of monomers, oligomers and polymers were performed using 1H, 13C, 29Si-NMR, FT-IR and GPC. The curing kinetics of photo-induced reactions were investigated through photo-differential scanning calorimetry (PDSC). The oxygen permeability, mechanical, coatings, and release properties of siloxanes were studied as a function of the backbone substitutions. The mechanical, coatings and released properties of cycloaliphatic siloxanes improved with respect to polydimethylsiloxanes. The thermal analysis of the cured films were carried out using differential scanning calorimetry (DSC). Viscoelastic properties of the cured siloxanes due to the variation of substitution at the siloxane backbone were measured using dynamic mechanical thermal analysis (DMTA). The cycloaliphatic substituted siloxanes showed an increased glass transition temperature and permeability but reduced crosslink density, conversion, and rate of curing with respect to polydimethylsiloxanes. Hybrids of siloxanes were prepared with

Removal of siloxanes in sewage sludge by thermal treatment with gas stripping

International Nuclear Information System (INIS)

Oshita, Kazuyuki; Omori, Keigo; Takaoka, Masaki; Mizuno, Tadao

2014-01-01

Highlights: • A new treatment of sewage sludge were studied to reduce siloxanes in biogas. • D5 of cyclic siloxane concentrations were the highest in sewage sludge. • Under optimal conditions, most of siloxanes in the sludge were removed previously. • By this treatment, CH 4 was 1.6-fold larger and siloxane in biogas 95% lower. - Abstract: In this study, thermal treatment with gas stripping of sewage sludge before anaerobic digestion to reduce siloxanes in the sludge and accelerate the anaerobic digestion was studied experimentally. Regarding siloxanes in the sludge, D5 concentrations were the highest. Siloxane concentrations in the digested sludge were decreased, versus those in thickened sludge, because siloxanes in the sludge are moved to the biogas during the anaerobic digestion. Thermal treatment and gas stripping experiments were conducted. The optimum conditions for siloxane removal from sludge were found to be thermal treatment with gas stripping at 80 °C with 0.5 L/min of air flow for 48 h. Under these conditions, approximately 90% of all siloxanes in the sludge were removed. Next, anaerobic digestion experiments were conducted with the optimally treated sludge and untreated sludge. The biogas volume of the optimally treated sludge was 1.6-fold larger than that of the untreated sludge. Furthermore, D5 contents in biogas from the optimally treated sludge were 95% lower than in biogas from untreated sludge. Thus, thermal treatment with gas stripping of sludge before anaerobic digestion was effective in increasing biogas amounts, decreasing siloxane concentrations in the biogas, and reducing the need for a siloxane removal process from the biogas

A novel non-enzymatic H{sub 2}O{sub 2} sensor based on polypyrrole nanofibers–silver nanoparticles decorated reduced graphene oxide nano composites

Energy Technology Data Exchange (ETDEWEB)

Moozarm Nia, Pooria, E-mail: pooriamn@yahoo.com; Lorestani, Farnaz, E-mail: farnaz.lorestani@siswa.um.edu.my; Meng, Woi Pei, E-mail: pmwoi@um.edu.my; Alias, Y., E-mail: yatimah70@um.edu.my

2015-03-30

Graphical abstract: - Highlights: • Decorating silver nanoparticles on the surface of graphene oxide nanocomposites. • Using and comparing two different electrochemical methods for reducing graphene oxide. • Investigating the effect of cyclic voltammetry and amperometry on electropolymerization of polypyrrole nanofibers. • The senor shows superior performances (LOD, LOQ, selectivity, repeatability, reproducibility and stability) towards H{sub 2}O{sub 2}. - Abstract: Graphene oxide (GO) decorated with silver nanoparticles (AgNPs), was electrochemically reduced on glassy carbon electrode (GCE) by an amperometry method (AMP-AgNPs-rGO/GCE). Then, Pyrrole was electropolymerized on the surface of the modified electrode through amperometry process in order to obtain nanofibers of polypyrrole (AMP-PpyNFs-AgNPs-rGO). Fourier-transform infrared transmission spectroscopy and X-ray diffraction approved that during the amperometry process, the GO and Ppy nanofibers were reduced and polymerized respectively and the silver nanoparticles were formed. Field emission scanning electron microscope images indicated that the silver nanoparticles were homogeneously distributed on the rGO surface with a narrow nano size distribution and polypyrrole synthesized in the form of nanofibers with diameter around 100 nm. The first linear section was in the range of 0.1–5 mM with a limit of detection of 1.099 and the second linear section raised to 90 mM with a correlation factor of 0.085 (S/N of 3)

Irradiation of gelatin. Important applications for the development of new materials

Energy Technology Data Exchange (ETDEWEB)

Del Mastro, N. L., E-mail: nlmastro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242, 05008-900 Sao Paulo (Brazil)

2011-11-15

Gelatin is obtained from a naturally occurring protein, collagen, by chemical and thermal hydrolysis. As a protein, gelatin is biodegradable. Among biomaterials, gelatin is an interesting material because the dehydrated gelatin is a partially crystalline polymer and has a relatively low melting point. Gelatin melts to a liquid when heated and solidifies when cooled again. Together with water, it forms a semi-solid colloid gel. If gelatin is placed in contact with cold water, some of the material dissolves, their solubility being determined by their manufacturing method. Ionizing radiation acting on aqueous biological systems produces labile intermediates. Macromolecular free radicals may be diffusion ally mobile in homogenous solutions but relatively immobile in gelled systems. In this paper, different works, some of them performed in our laboratory, are firstly described showing gelatin irradiation in diverse systems. We have already studied the mechanical properties of gelatin composites prepared with a natural fiber, plasticizer and treated by electron beam irradiation. Departing from that, the range of novel applications for gelatin composites like gelatin nanoparticles as biodegradable s and low cell toxic alternative carrier delivery systems are outlined. The potential and the possibilities of using gelatin irradiation for important applications for the development of new materials for medical and food industry are presented. (Author)

Enhanced Critical Size Defect Repair in Rabbit Mandible by Electrospun Gelatin/β-TCP Composite Nanofibrous Membranes

Directory of Open Access Journals (Sweden)

Mingming Xu

2015-01-01

Full Text Available The design and fabrication of biodegradable barrier membranes with satisfactory structure and composition remain a considerable challenge for periodontal tissue regeneration. We have developed a biomimetic nanofibrous membrane made from a composite of gelatin and β-tricalcium phosphate (β-TCP. We previously confirmed the in vitro biological performance of the membrane material, but the efficacy of the membranes in promoting bone repair in situ has not yet been examined. Gelatin/β-TCP composite nanofibers were fabricated by incorporation of 20 wt.% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite membranes presented a nonwoven structure with an interconnected porous network and had a rough surface due to the β-TCP nanoparticles, which were distributed widely and uniformly throughout the gelatin-fiber matrix. The repair efficacy of rabbit mandible defects implanted with bone substitute (Bio-Oss and covered with the gelatin/β-TCP composite nanofibrous membrane was evaluated in comparison with pure gelatin nanofibrous membrane. Gross observation, histological examination, and immunohistochemical analysis showed that new bone formation and defect closure were significantly enhanced by the composite membranes compared to the pure gelatin ones. From these results, we conclude that nanofibrous gelatin/β-TCP composite membranes could serve as effective barrier membranes for guided tissue regeneration.

Impurities in biogas - validation of analytical methods for siloxanes; Foeroreningar i biogas - validering av analysmetodik foer siloxaner

Energy Technology Data Exchange (ETDEWEB)

Arrhenius, Karine; Magnusson, Bertil; Sahlin, Eskil [SP Technical Research Institute of Sweden, Boraas (Sweden)

2011-11-15

Biogas produced from digester or landfill contains impurities which can be harmful for component that will be in contact with the biogas during its utilization. Among these, the siloxanes are often mentioned. During combustion, siloxanes are converted to silicon dioxide which accumulates on the heated surfaces in combustion equipment. Silicon dioxide is a solid compound and will remain in the engine and cause damages. Consequently, it is necessary to develop methods for the accurate determination of these compounds in biogases. In the first part of this report, a method for analysis of siloxanes in biogases was validated. The sampling was performed directly at the plant by drawing a small volume of biogas onto an adsorbent tube under a short period of time. These tubes were subsequently sent to the laboratory for analysis. The purpose of method validation is to demonstrate that the established method is fit for the purpose. This means that the method, as used by the laboratory generating the data, will provide data that meets a set of criteria concerning precision and accuracy. At the end, the uncertainty of the method was calculated. In the second part of this report, the validated method was applied to real samples collected in waste water treatment plants, co-digestion plants and plants digesting other wastes (agriculture waste). Results are presented at the end of this report. As expected, the biogases from waste water treatment plants contained largely higher concentrations of siloxanes than biogases from co-digestion plants and plants digesting agriculture wastes. The concentration of siloxanes in upgraded biogas regardless of which feedstock was digested and which upgrading technique was used was low.

TiO2/Bi2(BDC)3/BiOCl nanoparticles decorated ultrathin nanosheets with excellent photocatalytic reaction activity and selectivity

International Nuclear Information System (INIS)

Zhou, Shu-Mei; Ma, De-Kun; Cai, Ping; Chen, Wei; Huang, Shao-Ming

2014-01-01

Graphical abstract: TiO 2 /Bi 2 (BDC) 3 /BiOCl nanoparticles decorated ultrathin nanosheets showed excellent photocatalytic reaction activity and selectivity. - Highlights: • TiO 2 /Bi 2 (BDC) 3 /BiOCl nanoparticles decorated ultrathin nanosheets were synthesized through a facile hydrothermal process. • The products showed excellent photocatalytic activities for the degradation of various dyes. • The photocatalytic activities of the composite materials could be easily adjusted through tuning the content of TiO 2 . • TiO 2 /Bi 2 (BDC) 3 /BiOCl displayed obvious photocatalytic selectivity in mixed dyes systems of rhodamine B and eosin Y. - Abstract: Photocatalysts with excellent photocatalytic reaction activity and ideal selectivity are highly desirable for pollutants clearance and purification of targeted organics from a mixture. Continued efforts toward the goal, we here present a facile hydrothermal route to synthesize TiO 2 /Bi-benzenedicarboxylate/BiOCl nanoparticles decorated ultrathin nanosheets with a thickness less than 5 nm on a large scale. The as-synthesized products showed excellent photocatalytic activities for the degradation of various dyes such as rhodamine B, eosin Y and methylene blue in aqueous solution under visible light irradiation. The photocatalytic activities of TiO 2 /Bi-benzenedicarboxylate/BiOCl nanocomposites for the degradation of rhodamine B and eosin Y could be adjusted through tuning the content of TiO 2 . With increasing the amount of TiO 2 , the composites showed declining photocatalytic activities in decomposing of rhodamine B while on the contrary they displayed enhanced photocatalytic activities in decomposing of eosin Y. Interestingly, TiO 2 /Bi-benzenedicarboxylate/BiOCl composite nanosheets showed obvious photocatalytic selectivity in a mixed dyes system. The photocatalytic reaction and selectivity mechanisms of the nanocomposites for the degradation of the dyes were discussed on the basis of experimental results. The

Photocatalytic hydrogen evolution of palladium nanoparticles decorated black TiO2 calcined in argon atmosphere

Science.gov (United States)

Wu, Ming-Chung; Hsiao, Kai-Chi; Chang, Yin-Hsuan; Chan, Shun-Hsiang

2018-02-01

Black TiO2 nanoparticles (BTN) was prepared by sol-gel derived precursor calcined in an argon atmosphere. The synthesized BTN with trivalent titanium ion, structural defect, and oxygen vacancy shows a remarkably high absorbance in the visible light spectrum. BTN thus behaves a higher visible-active nanoreactor than white TiO2 nanoparticles (WTN) in the aqueous solution for organic pollutant degradation. Moreover, palladium decoration on the BTN surface (Pd-BTN) demonstrates a fascinating clean energy application. The obtained Pd-BTN fulfills a satisfied green material demand in the photocatalytic hydrogen production application. Pd-BTN calcined at 400 °C (Pd-BTN-400) shows the high photocatalytic hydrogen generation rate of 5200 μmol/g h under UV-A irradiation and 9300 μmol/g h under UV-B irradiation, respectively. The well-developed material, Pd-BTN-400, could be one of the best solutions in the concern of clean energy and water-purification with regard to the continuous environmental issue.

Preparation of carbon microspheres decorated with silver nanoparticles and their ability to remove dyes from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Chen, Qingchun [Department of Chemistry, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Wu, Qingsheng, E-mail: qswu@tongji.edu.cn [Department of Chemistry, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)

2015-02-11

Highlights: • Carbon microspheres decorated with silver nanoparticles (AgNP-CMSs) were prepared. • AgNP-CMSs show not only rapid and high adsorption capacity to methylene blue (MB) in water, but also excellent reusability. • It exhibits photocatalytic activity to Rhodamine B as well as MB under visible light. • The adsorption is from the ionic interactions but not the π–π conjugations. • The origin of photocatalysis is a surface plasmon resonance effect of AgNP on CMSs. - Abstract: Solid, but not hollow or porous, carbon microspheres decorated with silver nanoparticles (AgNP-CMSs) were prepared from silver nitrate and CMSs by a redox reaction at room temperature. The CMSs and AgNP-CMSs were characterized using X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and UV–vis spectrophotometry. Though with non-high specific surface area, the AgNP-CMSs exhibited a high adsorption capacity toward methylene blue (MB) in an aqueous solution. The AgNP-CMSs were able to remove all the MB from a solution of 30 mg/L MB in water within 1 min when the adsorbent concentration was 0.12 g/L. The AgNP-CMSs also exhibited good adsorption and photocatalytic activity in the decomposition of aqueous Rhodamine B as well as MB under visible light. FTIR was used to examine the interaction between AgNP-CMSs and MB, and the spectrum and more extra experiments suggest ionic interactions between cationic dyes and the negatively charged groups can be formed but not the presence of abundant π–π conjugations between dye molecules and the aromatic rings. The origin of the photocatalytic activity of AgNP-CMSs was attributed to a surface plasmon resonance (SPR) effect of the silver nanoparticles on the CMSs.

Fabrication and EMI shielding effectiveness of Ag-decorated highly porous poly(vinyl alcohol)/Fe2O3 nanofibrous composites

International Nuclear Information System (INIS)

Kim, Hae-Rim; Kim, Byoung-Suhk; Kim, Ick-Soo

2012-01-01

The Ag-decorated poly(vinyl alcohol) (PVA) composite nanofibrous webs incorporating Fe 2 O 3 nanoparticles were fabricated by electrospinning and metal-deposition methods for electromagnetic interference (EMI) shielding applications. The Ag-decorated PVA/Fe 2 O 3 composite nanofiber webs with various Ag thicknesses and different amounts of Fe 2 O 3 nanoparticles were prepared and used for EMI shielding measurement. For the EMI SE measurement, a near-field antenna measurement system was used. The measurement of EMI SE was carried out at the frequency range from 0.5 to 18 GHz, and the electromagnetic parameters were measured. The morphologies and microstructures of the resultant PVA/Fe 2 O 3 composite nanofiber webs were characterized using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), respectively. The effects of surface morphologies and Fe 2 O 3 nanoparticles on the EMI shielding effectiveness of Ag-decorated PVA/Fe 2 O 3 composite nanofiber webs were investigated. -- Highlights: ► We prepare Ag-decorated poly(vinyl alcohol) nanowebs incorporating Fe 2 O 3 nanoparticles. ► Solvents will affect the fiber morphologies and Fe 2 O 3 nanoparticles dispersion. ► EMI shielding effectiveness depends on the metal thickness and Fe 2 O 3 nanoparticles dispersion.

Physical, chemical and biological studies of gelatin/chitosan based transdermal fims with embedded silver nanoparticles

Directory of Open Access Journals (Sweden)

Sneha Paul

2015-12-01

Full Text Available Objective: To study the physical, chemical and biological properties of composite chitosangelatin transdermal film along with silver nanoparticles as binding agent and determine the compatibility of the prepared amalgamation towards wound management. Methods: Transdermal film preparations were done by solvent casting method containing different concentrations of biological synthesized silver nanoparticles. The films were characterized by using scanning electron microscope for their morphology and the determination of silver metal was done by using inductively coupled plasma atomic emission spectroscopy. Then a quantity of silver nanoparticles was further proceeded by physiochemical parameters (weight, thickness, temperature, solubility, absorption, tensile strength, in vitro drug release and skin permeation and biological parameters studies (anti-microbial, cytotoxicity and reactive oxygen species. Results: The film prepared by utilizing 2 g of gelatin and 0.5 g of chitosan exhibited better results. The physiochemical parameters studies revealed higher concentration of silver nanoparticles would give better results. In vitro drug release studies through dialysis and skin permeation showed the release of drug versus time (h. These films had shown excellent inhibition against Streptococcus and Escherichia coli species. Cytotoxicity study by MTT indicated the mild toxicity existed as the concentration of silver nanoparticles increased. Reactive oxygen species generation studies of transdermal film by using 2'7'-dichlorofluorescein diacetate assay demonstrated that the fluorescent cells were found in the higher concentration, which indicated cell damage (reactive oxygen species generated. Conclusions: Based on these observations, in vitro performances against various characteristics of transdermal film, would be utilized as a distinct dressing material and patches accessible in market.

Decoration of Multi-walled Carbon Nanotubes by Metal ...

African Journals Online (AJOL)

NICO

tures inside the nanotubes to increase the available surface for catalysis6 or in ... most common method to decorate CNTs by metal nanoparticles and metal oxides due .... 2.6 Characterization of Carbon Nanotubes, Metal Nano- particles and ...

Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery

Directory of Open Access Journals (Sweden)

Hu Y

2017-11-01

Full Text Available Yan Hu,1 Lei Ke,2 Hao Chen,1 Ma Zhuo,1 Xinzhou Yang,1 Dan Zhao,1 Suying Zeng,1 Xincai Xiao1 1Department of Pharmaceutics, School of Pharmaceutical Science, South-Central University for Nationalities, 2Department of Medicinal Chemistry, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China Abstract: To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs, which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy. Keywords: multifunctional, membrane-controlled, natural materials, mesoporous silica nanoparticles, targeted drug delivery

CeO{sub 2} nanoparticles decorated multi-walled carbon nanotubes for electrochemical determination of guanine and adenine

Energy Technology Data Exchange (ETDEWEB)

Wei Yan [College of Chemistry and Materials Sciences, Anhui Normal University, Wuhu 241000 (China); Department of Chemistry, Wannan Medical College, Wuhu 241002 (China); Huang Qinan [Department of Chemistry, Wannan Medical College, Wuhu 241002 (China); Li Maoguo [College of Chemistry and Materials Sciences, Anhui Normal University, Wuhu 241000 (China); Huang Xingjiu [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); Fang Bin, E-mail: binfang_47@yahoo.com.cn [College of Chemistry and Materials Sciences, Anhui Normal University, Wuhu 241000 (China); Wang Lun, E-mail: wanglun@mail.ahnu.edu.cn [College of Chemistry and Materials Sciences, Anhui Normal University, Wuhu 241000 (China)

2011-10-01

Sub-10 nm CeO{sub 2} nanoparticles decorated multi-walled carbon nanotubes has been constructed for electrochemial determination of guanine and adenine. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize the nanoparticles CeO{sub 2}/MWCNTs. Electrochemical impedance spectroscopy (EIS) was used to characterize the electrode modifying process. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrocatalytic activity toward the electrochemical oxidation of guanine and adenine. The detection limit (S/N = 3) for adenine and guanine was found to be 20 and 10 nM, respectively. The obtained sensitivity toward guanine and adenine was 1.26 and 1.13 {mu}A/{mu}M in the linear concentration range 5-50 {mu}M and 5-35 {mu}M, respectively. These results demonstrate that the carbon nanotubes could provide huge locations and facilitate the adsorptive accumulation of the guanine and adenine, and the CeO{sub 2} nanoparticles are promising substrates for the development of high-performance electrocatalysts for biosensing.

Substrate decoration for improvement of current-carrying capabilities of YBa2Cu3Ox thin films

International Nuclear Information System (INIS)

Khoryushin, Alexey V.; Mozhaev, Peter B.; Mozhaeva, Julia E.; Bdikin, Igor K.; Zhao, Yue; Andersen, Niels H.; Jacobsen, Claus S.; Hansen, Jørn Bindslev

2013-01-01

Highlights: ► Effects of substrate decoration on properties of YBCO thin films were studied. ► Y 2 O 3 nanoparticles, ultra-thin Y 2 O 3 and Y:ZrO 2 layers were used as decoration layer. ► Decoration improves j C (5 T and 50 K) up to 0.97 MA/cm 2 vs. 0.76 MA/cm 2 for a reference film. ► Ultra-thin layer of yttria and yttria nanoparticles have a similar effect on YBCO. ► Y 2 O 3 decoration results in power law coefficient α = 0.3 vs. α = 0.4 for a reference film. -- Abstract: The effects of substrate decoration with yttria and Y:ZrO 2 on the structural and electrical properties of the YBa 2 Cu 3 O x (YBCO) thin films are studied. The films were deposited on (LaAlO 3 ) 3 –(Sr 2 AlTaO 8 ) 7 substrates by pulsed laser deposition. Two different structures of decoration layer were applied, a template layer of nanoparticles and an uniform ultra-thin layer. Significant improvement of current-carrying capabilities was observed, especially at high external magnetic fields. Structural studies of these films reveal the presence of extended linear defects in the YBCO matrix. The formation of these structures is attributed to seeding of randomly oriented YBCO grains due to suppression of epitaxy in the very beginning of the deposition. The films of both kinds of decoration layers show nearly the same improvement of j C over the reference film at 77 and 50 K: j C (5T and 50 K) reaches 0.92 and 0.97 MA/cm 2 for uniform and template decoration layers. At 5 and 20 K the effect of template decoration layers is more beneficial: j C (5T and 20 K) values are 3.5 and 4.1 MA/cm 2 , j C (5T and 5 K) values are 6.4 and 7.9 MA/cm 2 , for uniform and template decoration layers, respectively

Amino-siloxane composition and methods of using the same

Science.gov (United States)

O'Brien, Michael Joseph; Farnum, Rachel Lizabeth; Perry, Robert James

2018-03-20

An amino-siloxane composition is presented. The amino-siloxane composition includes structure (I): ##STR00001## wherein R1 is independently at each occurrence a C1-C5 aliphatic radical; R2 is a C3-C.4 aliphatic radical; R3 is a C1-C5 aliphatic radical or R4, wherein R4 comprises structure (II): ##STR00002## and X is an electron donating group. Methods of reducing an amount of carbon dioxide in a process stream using the amino-siloxane composition are also presented.

Preparation, characterization, and antibacterial activity of γ-irradiated silver nanoparticles in aqueous gelatin

Science.gov (United States)

Darroudi, Majid; Ahmad, Mansor B.; Hakimi, Mohammad; Zamiri, Reza; Zak, Ali Khorsand; Hosseini, Hasan Ali; Zargar, Mohsen

2013-04-01

Colloidal silver nanoparticles (Ag-NPs) were obtained through γ-irradiation of aqueous solutions containing AgNO3 and gelatin as a silver source and stabilizer, respectively. The absorbed dose of γ-irradiation influences the particle diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) and transmission electron microscopy (TEM) images. When the γ-irradiation dose was increased (from 2 to 50 kGy), the mean particle size was decreased continuously as a result of γ-induced Ag-NPs fragmentation. The antibacterial properties of the Ag-NPs were tested against Methicillinresistant Staphylococcus aureus (MRSA) (Gram-positive) and Pseudomonas aeruginosa (P.a) (Gram-negative) bacteria. This approach reveals that the γ-irradiation-mediated method is a promising simple route for synthesizing highly stable Ag-NPs in aqueous solutions with good antibacterial properties for different applications.

Evolution of consciousness of exposure to siloxanes-review of publications.

Science.gov (United States)

Mojsiewicz-Pieńkowska, Krystyna; Krenczkowska, Dominika

2018-01-01

The purpose of this description is to review scientific literature from 1944 to 2017 as a source of information on the reasons for the increased interest in siloxanes (silicones). Not only the research area, but first, the changes in the tendency of research aims are important issues in the evaluation. On the one hand, the authors emphasize the unique properties of linear and cyclic siloxanes, providing many examples of beneficial applications, and on the other hand, there are some warnings of overcoming of the safety barrier of their presence in human environment. Analyzing the results from the SCOPUS database, it can be argued that the increased interest of scientists and government agencies particularly relates to the analysis of siloxanes in biological and environmental samples. This is caused not only by the widespread use of various siloxanes in the pharmaceutical, medical, cosmetic and food industries, but also by the direct contact of these compounds with tissues, as well as an increased access to knowledge and modern research tools that have developed the awareness of hazards. The development of research methods enables not only constant monitoring of progressively lower siloxanes concentrations in various samples, but because of the specificity of these methods, it also enables an identification of specific siloxane compounds and evaluation of their effects on humans and environment. This paper discusses the issues of the evolution of consciousness of exposure to siloxanes due to their increased synthesis and widespread use in many areas of human life, which contributes to environmental pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and Property of Ag(NP)/catechin/Gelatin Nanofiber

Science.gov (United States)

Nasir, Muhamad; Apriani, Dita

2017-12-01

Nanomaterial play important role future industry such as for the medical, food, pharmaceutical and cosmetic industry. Ag (NP) and catechin exhibit antibacterial property. Ag(NP) with diameter around 15 nm was synthesis by microwaved method. We have successfully produce Ag(NP)/catechin/gelatin nanofiber composite by electrospinning process. Ag(NP)/catechin/gelatin nanofiber was synthesized by using gelatin from tuna fish, polyethylene oxide (PEO), acetic acid as solvent and silver nanoparticle(NP)/catechin as bioactive component, respectively. Morphology and structure of bioactive catechin-gelatin nanofiber were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR), respectively. SEM analysis showed that morphology of nanofiber composite was smooth and had average diameter 398.97 nm. FTIR analysis results were used to confirm structure of catechin-gelatin nanofiber. It was confirmed by FTIR that specific vibration band peak amide A (N-H) at 3286,209 cm-1, amide B (N-H) 3069,396 cm-1, amide I (C=O) at 1643,813 cm-1, amide II (N-H and CN) at 1538,949 cm-1, amide III (C-N) at 1276,789 cm-1, C-O-C from polyethylene oxide at 1146,418 cm-1, respectively. When examined to S. Aureus bacteria, Ag/catechin/gelatin nanofiber show inhabitation performance around 40.44%. Ag(NP)/catechin/gelatin nanofiber has potential application antibacterial medical application.

Glancing-incidence X-ray diffraction of Ag nanoparticles in gold lustre decoration of Italian Renaissance pottery

Energy Technology Data Exchange (ETDEWEB)

Bontempi, E.; Colombi, P.; Depero, L.E. [Universita di Brescia, Laboratorio di Chimica per le Tecnologie and INSTM, Brescia (Italy); Cartechini, L. [Universita di Perugia, Istituto di Scienze e Tecnologie Molecolari-CNR, Sezione di Perugia, Perugia (Italy); Presciutti, F.; Brunetti, B.G. [Universita di Perugia, INSTM and Centro di Eccellenza SMAArt, Dipartimento di Chimica, Perugia (Italy); Sgamellotti, A. [Universita di Perugia, Istituto di Scienze e Tecnologie Molecolari-CNR, Sezione di Perugia, Perugia (Italy); Universita di Perugia, INSTM and Centro di Eccellenza SMAArt, Dipartimento di Chimica, Perugia (Italy)

2006-06-15

Lustre is known as one of the most significant decorative techniques of Medieval and Renaissance pottery in the Mediterranean basin, characterized by brilliant gold and red metallic reflections and iridescence effects. Previous studies by various techniques (SEM-EDS and TEM, UV-VIS, XRF, RBS and EXAFS) demonstrated that lustre consists of a heterogeneous metal-glass composite film, formed by Cu and Ag nanoparticles dispersed within the outer layer of a tin-opacified lead glaze. In the present work the investigation of an original gold lustre sample from Deruta has been carried out by means of glancing-incidence X-ray diffraction techniques (GIXRD). The study was aimed at providing information on structure and depth distribution of Ag nanoparticles. Exploiting the capability of controlling X-ray penetration in the glaze by changing the incidence angle, we used GIXRD measurements to estimate non-destructively thickness and depth of silver particles present in the first layers of the glaze. (orig.)

Glancing-incidence X-ray diffraction of Ag nanoparticles in gold lustre decoration of Italian Renaissance pottery

International Nuclear Information System (INIS)

Bontempi, E.; Colombi, P.; Depero, L.E.; Cartechini, L.; Presciutti, F.; Brunetti, B.G.; Sgamellotti, A.

2006-01-01

Lustre is known as one of the most significant decorative techniques of Medieval and Renaissance pottery in the Mediterranean basin, characterized by brilliant gold and red metallic reflections and iridescence effects. Previous studies by various techniques (SEM-EDS and TEM, UV-VIS, XRF, RBS and EXAFS) demonstrated that lustre consists of a heterogeneous metal-glass composite film, formed by Cu and Ag nanoparticles dispersed within the outer layer of a tin-opacified lead glaze. In the present work the investigation of an original gold lustre sample from Deruta has been carried out by means of glancing-incidence X-ray diffraction techniques (GIXRD). The study was aimed at providing information on structure and depth distribution of Ag nanoparticles. Exploiting the capability of controlling X-ray penetration in the glaze by changing the incidence angle, we used GIXRD measurements to estimate non-destructively thickness and depth of silver particles present in the first layers of the glaze. (orig.)

Glancing-incidence X-ray diffraction of Ag nanoparticles in gold lustre decoration of Italian Renaissance pottery

Science.gov (United States)

Bontempi, E.; Colombi, P.; Depero, L. E.; Cartechini, L.; Presciutti, F.; Brunetti, B. G.; Sgamellotti, A.

2006-06-01

Lustre is known as one of the most significant decorative techniques of Medieval and Renaissance pottery in the Mediterranean basin, characterized by brilliant gold and red metallic reflections and iridescence effects. Previous studies by various techniques (SEM-EDS and TEM, UV-VIS, XRF, RBS and EXAFS) demonstrated that lustre consists of a heterogeneous metal-glass composite film, formed by Cu and Ag nanoparticles dispersed within the outer layer of a tin-opacified lead glaze. In the present work the investigation of an original gold lustre sample from Deruta has been carried out by means of glancing-incidence X-ray diffraction techniques (GIXRD). The study was aimed at providing information on structure and depth distribution of Ag nanoparticles. Exploiting the capability of controlling X-ray penetration in the glaze by changing the incidence angle, we used GIXRD measurements to estimate non-destructively thickness and depth of silver particles present in the first layers of the glaze.

Plasmonic nanoparticles-decorated diatomite biosilica: extending the horizon of on-chip chromatography and label-free biosensing.

Science.gov (United States)

Kong, Xianming; Li, Erwen; Squire, Kenny; Liu, Ye; Wu, Bo; Cheng, Li-Jing; Wang, Alan X

2017-11-01

Diatomite consists of fossilized remains of ancient diatoms and is a type of naturally abundant photonic crystal biosilica with multiple unique physical and chemical functionalities. In this paper, we explored the fluidic properties of diatomite as the matrix for on-chip chromatography and, simultaneously, the photonic crystal effects to enhance the plasmonic resonances of metallic nanoparticles for surface-enhanced Raman scattering (SERS) biosensing. The plasmonic nanoparticle-decorated diatomite biosilica provides a lab-on-a-chip capability to separate and detect small molecules from mixture samples with ultra-high detection sensitivity down to 1 ppm. We demonstrate the significant potential for biomedical applications by screening toxins in real biofluid, achieving simultaneous label-free biosensing of phenethylamine and miR21cDNA in human plasma with unprecedented sensitivity and specificity. To the best of our knowledge, this is the first time demonstration to detect target molecules from real biofluids by on-chip chromatography-SERS techniques. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amino-siloxane composition and methods of using the same

Science.gov (United States)

O'Brien, Michael Joseph; Farnum, Rachel Lizabeth; Perry, Robert James

2016-08-30

An amino-siloxane composition is presented. The amino-siloxane composition includes structure (I): ##STR00001## wherein R.sup.1 is independently at each occurrence a C.sub.1-C.sub.5 aliphatic radical; R.sup.2 is a C.sub.3-C.sub.4 aliphatic radical; R.sup.3 is a C.sub.1-C.sub.5 aliphatic radical or R.sup.4, wherein R.sup.4 comprises structure (II): ##STR00002## and X is an electron donating group. Methods of reducing an amount of carbon dioxide in a process stream using the amino-siloxane composition are also presented.

Enhanced non-enzymatic glucose sensing based on copper nanoparticles decorated nitrogen-doped graphene.

Science.gov (United States)

Jiang, Ding; Liu, Qian; Wang, Kun; Qian, Jing; Dong, Xiaoya; Yang, Zhenting; Du, Xiaojiao; Qiu, Baijing

2014-04-15

Copper nanoparticles (NPs) decorated nitrogen-doped graphene (Cu-N-G) was prepared by a facile thermal treatment, and further employed as a novel sensing material for fabricating the sensitive non-enzymatic glucose sensor. Compared with pure Cu NPs, the Cu-N-G showed enhanced electrocatalytic activity to glucose oxidation due to the integration of N-G, which exhibited the oxidation peak current of glucose ca. 23-fold higher than that of pure Cu NPs. The presented sensor showed excellent performances for glucose detection including wide linear range of 0.004-4.5 mM, low detection limit (1.3 μM, S/N=3), high sensitivity (48.13 μA mM(-1)), fast response time (doped graphene as enhanced materials in fabricating sensors for chemical and biochemical analysis. © 2013 Published by Elsevier B.V.

A novel enzymatic glucose sensor based on Pt nanoparticles-decorated hollow carbon spheres-modified glassy carbon electrode

Science.gov (United States)

Luhana, Charles; Bo, Xiang-Jie; Ju, Jian; Guo, Li-Ping

2012-10-01

A new glucose biosensor was developed based on hollow carbon spheres decorated with platinum nanoparticles (Pt/HCSs)-modified glassy carbon electrode immobilized with glucose oxidase (GOx) with the help of Nafion. The Pt nanoparticles were well dispersed on the HCSs with an average size of 2.29 nm. The detection of glucose was achieved via electrochemical detection of the enzymatically liberated H2O2 at +0.5 V versus Ag/AgCl at physiologic pH of 7.4. The Pt/HCSs-modified electrode exhibited excellent electrocatalytic activities toward both the oxidation and reduction of H2O2. The glucose biosensor showed good electrocatalytic performance in terms of high sensitivity (4.1 μA mM-1), low detection limit (1.8 μM), fast response time tested with this biosensor and a good recovery was achieved for the two spiked serum samples.

Ambipolar transport of silver nanoparticles decorated graphene oxide field effect transistors

Science.gov (United States)

Sarkar, Kalyan Jyoti; Sarkar, K.; Pal, B.; Kumar, Aparabal; Das, Anish; Banerji, P.

2018-05-01

In this article, we report ambipolar field effect transistor (FET) by using graphene oxide (GO) as a gate dielectric material for silver nanoparticles (AgNPs) decorated GO channel layer. GO was synthesized by Hummers' method. The AgNPs were prepared via photochemical reduction of silver nitrate solution by using monoethanolamine as a reducing agent. Morphological properties of channel layer were characterized by Field Effect Scanning Electron Microscopy (FESEM). Fourier Transform Infrared Spectroscopy (FTIR) was carried out to characterize GO thin film. For device fabrication gold (Au) was deposited as source-drain contact and aluminum (Al) was taken as bottom contact. Electrical measurements were performed by back gate configuration. Ambipolar transport behavior was explained from transfer characteristics. A maximum electron mobiliy of 6.65 cm2/Vs and a hole mobility of 2.46 cm2/Vs were extracted from the transfer characteristics. These results suggest that GO is a potential candidate as a gate dielectric material for thin film transistor applications and also provides new insights in GO based research.

Preparation and physicochemistry properties of smart edible films based on gelatin-starch nanoparticles.

Science.gov (United States)

Tao, Furong; Shi, Chengmei; Cui, Yuezhi

2018-04-24

Among the natural polymers able to form edible films, starch and gelatin (Gel) are potential sources. Corn starch is a polysaccharide widely produced around the world, and gelatin differs from other hydrocolloids as a fully digestible protein, containing nearly all the essential amino acids, except tryptophan. Based on this, with advantages such as abundance, relatively low cost, biodegradability, and edibility, studies considering alternative systems for food protection that utilize biopolymers have increased significantly in the recent years. A novel macromolecular crosslinker Starch-BTCAD-NHS (starch - butanetetracarboxylic acid dianhydride - N-hydroxysuccinimide, SBN) was successfully prepared to modify gelatin film. Compared with the blank gelatin films, the resulting SBN-Gel films exhibited the improved surface hydrophobicity, the higher tense strength and elongation-at-break, the lower Young's modulus values, the greater opacity, the poorer water vapor uptake properties and better anti-degradation capacity. The modified gelatin film material with advanced properties obtained in this work was safe, stable eco-friendly and biorefractory, and was an ideal choice to form a packaging in food industry. Also, the crosslinking SBN-gelatin coating was effective in reducing the corruption and extending the shelf life for the peeled apple substantially. This article is protected by copyright. All rights reserved.

Preparation of ultra-thin polypyrrole nanosheets decorated with Ag nanoparticles and their application in hydrogen peroxide detection

International Nuclear Information System (INIS)

Mahmoudian, M.R.; Alias, Y.; Basirun, W.J.; Ebadi, M.

2012-01-01

Highlights: ► Ag nanoparticles-decorated ultra thin polypyrrole nanosheets were prepared. ► Higher surface area of the polymer increased interaction between the polymer and Ag + . ► The sensitivity was estimated to be 4.477 μA mM −1 for linear segment. ► The LOD and LOQ (S/N = 3) were estimated to be 0.57 μM and 1.93 μM, respectively. - Abstract: This study examines the preparation of ultra-thin polypyrrole nanosheets decorated with Ag nanoparticles (Ag-UTPNSs) and their application in the enzyme-less detection of hydrogen peroxide (H 2 O 2 ) detection. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results confirmed that Ag nanoparticles (NPs) were deposited onto the surface of the UTPNSs. The increase of the H 2 O 2 reduction current peak to 120 μA in the presence of the Ag-UTPNS/glassy carbon electrode (GCE) as compared to the UTPNS/GCE indicates that the sensitivity of the electrode to H 2 O 2 is significant. This observation can be explained by the larger surface area of the UTPNSs, which can increase the interactions between the polymer and the AgNO 3 solution during the deposition of the Ag NPs, and by the small size of the deposited Ag NPs, which can produce a surface area of Ag that is suitable for the reaction with H 2 O 2 . The amperometric responses show that the limit of detection, the limit of quantification (S/N = 3) and the sensitivity are estimated to be 0.57 μM, 1.93 μM and 4.477 μA mM −1 , respectively, for the linear segment. The results of the reproducibility experiments show that the use of Ag-UTPNS/GCE is feasible for the quantitative detection of certain concentration ranges of H 2 O 2 .

Amino-siloxane composition and methods of using the same

Energy Technology Data Exchange (ETDEWEB)

O' Brien, Michael Joseph; Farnum, Rachel Lizabeth; Perry, Robert James

2018-03-20

An amino-siloxane composition is presented. The amino-siloxane composition includes structure (I): ##STR00001## wherein R¹ is independently at each occurrence a C₁-C₅ aliphatic radical; R² is a C₃-C.₄ aliphatic radical; R³ is a C₁-C₅ aliphatic radical or R⁴, wherein R⁴ comprises structure (II): ##STR00002## and X is an electron donating group. Methods of reducing an amount of carbon dioxide in a process stream using the amino-siloxane composition are also presented.

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

International Nuclear Information System (INIS)

Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

2013-01-01

Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

Energy Technology Data Exchange (ETDEWEB)

Nam, Sangchul; Namkoong, Wan [Department of Environmental Engineering, Konkuk University, Hwayang-Dong, Gwangjin-Gu, Seoul 143-701 (Korea, Republic of); Kang, Jeong-Hee; Park, Jin-Kyu [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of); Lee, Namhoon, E-mail: nhlee@anyang.ac.kr [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of)

2013-10-15

Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

Design of Magnetic Gelatine/Silica Nanocomposites by Nanoemulsification: Encapsulation versus in Situ Growth of Iron Oxide Colloids

Directory of Open Access Journals (Sweden)

Joachim Allouche

2014-07-01

Full Text Available The design of magnetic nanoparticles by incorporation of iron oxide colloids within gelatine/silica hybrid nanoparticles has been performed for the first time through a nanoemulsion route using the encapsulation of pre-formed magnetite nanocrystals and the in situ precipitation of ferrous/ferric ions. The first method leads to bi-continuous hybrid nanocomposites containing a limited amount of well-dispersed magnetite colloids. In contrast, the second approach allows the formation of gelatine-silica core-shell nanostructures incorporating larger amounts of agglomerated iron oxide colloids. Both magnetic nanocomposites exhibit similar superparamagnetic behaviors. Whereas nanocomposites obtained via an in situ approach show a strong tendency to aggregate in solution, the encapsulation route allows further surface modification of the magnetic nanocomposites, leading to quaternary gold/iron oxide/silica/gelatine nanoparticles. Hence, such a first-time rational combination of nano-emulsion, nanocrystallization and sol-gel chemistry allows the elaboration of multi-component functional nanomaterials. This constitutes a step forward in the design of more complex bio-nanoplatforms.

Hydrazine-induced thermo-reversible optical shifts in silver-gelatin bionanocomposites

Science.gov (United States)

Aimé, Carole; Rietveld, Ivo B.; Coradin, Thibaud

2011-03-01

Bionanocomposites formed by in situ growth of silver nanoparticles within gelatin gels exhibit large (up to 100 nm) thermo-reversible optical shifts resulting from the enhancement of gel matrix scattering by the interaction of the biopolymer with the hydrazine reducing agent.

Carbon nanotubes with silver nanoparticle decoration and conductive polymer coating for improving the electrical conductivity of polycarbonate composites

KAUST Repository

Patole, Archana S.

2015-01-01

We proposed a strategy to enhance the conductivity of polycarbonate by using three-phase hybrid metallic/non-metallic fillers. Ethylene diamine (EDA) functionalized multiwalled carbon nanotubes (MWCNT-EDA) are first decorated with silver nanoparticles. These Ag/ MWCNT-EDA fillers are then coated with a conductive layer of ethylene glycol treated PEDOT: PSS (poly [3,4-ethylenedioxythiophene]: poly [styrenesulfonate]) (EP). In such an approach, the MWCNT backbone is covered by a highly conductive coating made of Ag nanoparticles surrounded by EP. To understand how Ag and EP form a highly conductive coating, the effect of different wt% of Ag nanoparticles on EP was studied. Ag nanoparticles around the size of 128 ± 28 nmeffectively lowered the volume resistivity of bulk EP, resulting in a highly conducting Ag/EP blend. We found that in the final Ag/MWCNT-EDA/EP assembly, the EP coating enhances the electrical conductivity in two ways: (1) it is an efficient dispersing agent that helps in achieving a uniform dispersion of the Ag/MWCNT-EDA and (2) it acts as a conductive bridge between particles (Ag and MWCNT-EDA), reducing the particle to particle resistivity. When inserted into polycarbonate, this three-phase blend successfully reduced the volume resistivity of the polymer by two orders of magnitude compared with previous approaches.

Fish gelatin.

Science.gov (United States)

Boran, Gokhan; Regenstein, Joe M

2010-01-01

Gelatin is a multifunctional ingredient used in foods, pharmaceuticals, cosmetics, and photographic films as a gelling agent, stabilizer, thickener, emulsifier, and film former. As a thermoreversible hydrocolloid with a narrower gap between its melting and gelling temperatures, both of which are below human body temperature, gelatin provides unique advantages over carbohydrate-based gelling agents. Gelatin is mostly produced from pig skin, and cattle hides and bones. Some alternative raw materials have recently gained attention from both researchers and the industry not just because they overcome religious concerns shared by Jews and Muslims but also because they provide, in some cases, technological advantages over mammalian gelatins. Fish skins from a number of fish species are among the other sources that have been comprehensively studied as sources for gelatin production. Fish skins have a significant potential for the production of high-quality gelatin with different melting and gelling temperatures over a much wider range than mammalian gelatins, yet still have a sufficiently high gel strength and viscosity. Gelatin quality is industrially determined by gel strength, viscosity, melting or gelling temperatures, the water content, and microbiological safety. For gelatin manufacturers, yield from a particular raw material is also important. Recent experimental studies have shown that these quality parameters vary greatly depending on the biochemical characteristics of the raw materials, the manufacturing processes applied, and the experimental settings used for quality control tests. In this review, the gelatin quality achieved from different fish species is reviewed along with the experimental procedures used to determine gelatin quality. In addition, the chemical structure of collagen and gelatin, the collagen-gelatin conversion, the gelation process, and the gelatin market are discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

Concentrations and assessment of exposure to siloxanes and synthetic musks in personal care products from China

International Nuclear Information System (INIS)

Lu Yan; Yuan Tao; Wang Wenhua; Kannan, Kurunthachalam

2011-01-01

We investigated the concentrations and profiles of 15 siloxanes (four cyclic siloxanes, D 4 -D 7 ; 11 linear siloxanes, L 4 -L 14 ), four synthetic musks (two polycyclic musks, HHCB and AHTN; two nitro musks, MX and MK), and HHCB-lactone, in 158 personal care products marketed in China. Siloxanes were detected in 88% of the samples analyzed, at concentrations as high as 52.6 mg g -1 ; Linear siloxanes were the predominant compounds. Among synthetic musks, more than 80% of the samples contained at least one of these compounds, and their total concentrations were as high as 1.02 mg g -1 . HHCB was the predominant musk in all of the samples analyzed, on average, accounting for 52% of the total musk concentrations. Based on the median concentrations of siloxanes and musks and the average daily usage amounts of consumer products, dermal exposure rates in adults were calculated to be 3.69 and 3.38 mg d -1 for siloxanes and musks, respectively. - Highlights: → Siloxanes and synthetic musks are determined in personal care products. → Highest siloxane concentration was 52.6 mg g -1 . → Highest musk concentration was 1.02 mg g -1 . → Daily dermal exposure rates of siloxanes and musks were in mg levels. → Dermal exposure is a major pathway of human exposure to siloxanes and musks. - Dermal application of several personal care products is a major source of human exposure to cyclic and linear siloxanes.

Concentrations and assessment of exposure to siloxanes and synthetic musks in personal care products from China

Energy Technology Data Exchange (ETDEWEB)

Lu Yan [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wadsworth Center, New York State Department of Health and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, PO Box 509, Albany, NY 12201-0509 (United States); Yuan Tao; Wang Wenhua [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Kannan, Kurunthachalam, E-mail: kkannan@wadsworth.org [Wadsworth Center, New York State Department of Health and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, PO Box 509, Albany, NY 12201-0509 (United States); International Joint Research Center for Persistent Toxic Substances, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China)

2011-12-15

We investigated the concentrations and profiles of 15 siloxanes (four cyclic siloxanes, D{sub 4}-D{sub 7}; 11 linear siloxanes, L{sub 4}-L{sub 14}), four synthetic musks (two polycyclic musks, HHCB and AHTN; two nitro musks, MX and MK), and HHCB-lactone, in 158 personal care products marketed in China. Siloxanes were detected in 88% of the samples analyzed, at concentrations as high as 52.6 mg g{sup -1}; Linear siloxanes were the predominant compounds. Among synthetic musks, more than 80% of the samples contained at least one of these compounds, and their total concentrations were as high as 1.02 mg g{sup -1}. HHCB was the predominant musk in all of the samples analyzed, on average, accounting for 52% of the total musk concentrations. Based on the median concentrations of siloxanes and musks and the average daily usage amounts of consumer products, dermal exposure rates in adults were calculated to be 3.69 and 3.38 mg d{sup -1} for siloxanes and musks, respectively. - Highlights: > Siloxanes and synthetic musks are determined in personal care products. > Highest siloxane concentration was 52.6 mg g{sup -1}. > Highest musk concentration was 1.02 mg g{sup -1}. > Daily dermal exposure rates of siloxanes and musks were in mg levels. > Dermal exposure is a major pathway of human exposure to siloxanes and musks. - Dermal application of several personal care products is a major source of human exposure to cyclic and linear siloxanes.

Enzymatic synthesis of lignin-siloxane hybrid functional polymers.

Science.gov (United States)

Prasetyo, Endry Nugroho; Kudanga, Tukayi; Fischer, Roman; Eichinger, Reinhard; Nyanhongo, Gibson S; Guebitz, Georg M

2012-02-01

This study combines the properties of siloxanes and lignin polymers to produce hybrid functional polymers that can be used as adhesives, coating materials, and/or multifunctionalized thin-coating films. Lignin-silica hybrid copolymers were synthesized by using a sol-gel process. Laccases from Trametes hirsuta were used to oxidize lignosulphonates to enhance their reactivity towards siloxanes and then were incorporated into siloxane precursors undergoing a sol-gel process. In vitro copolymerization studies using pure lignin monomers with aminosilanes or ethoxytrimethylsilane and analysis by ²⁹Si NMR spectroscopy revealed hybrid products. Except for kraft lignin, an increase in lignin concentration positively affected the tensile strength in all samples. Similarly, the viscosity generally increased in all samples with increasing lignin concentration and also affected the curing time. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyvalent integrin antagonist-decorated superparamagnetic iron oxide nanoparticles for triggering apoptosis in human leukemia cancer cells

International Nuclear Information System (INIS)

Say, Rıdvan; Yazar, Suzan; Uğur, Alper; Hür, Deniz; Denizli, Adil; Ersöz, Arzu

2013-01-01

Integrin family members are the main mediators of cell adhesion to the extracellular matrix and active as intra- and extracellular signaling molecules in a variety of processes. They bind to their ligands by interacting with short amino acid sequences, that is, RGD (arginine-glycine-aspartic acid) sequence. RGD sequences have been used to enhance cell binding to artificial surfaces, so RGD mimics have been used to block integrin binding to its ligand. Integrin–ligand interactions are dependent on divalent cations, and Mg 2+ provide higher-affinity binding to ligand for many integrins. In this study, we have designed new integrin antagonists using methacryloyl amidoaspartic acid (MAASP) monomer-conjugated silanized super paramagnetic iron oxide nanoparticles (SPIONs, the size of the nanoparticles was verified with an average size of 32.6 nm) and poly(MAASP-co-EDMA) shell-decorated silanized SPIONs. Several mechanisms have been proposed to describe uptake of modified SPIONs into the cells, including receptor-mediated endocytosis. Our aim is to bind these modified SPIONs to the integrin-mediated aspartic acid ends of MAASP monomers and block integrin binding to their ligand.

Polyvalent integrin antagonist-decorated superparamagnetic iron oxide nanoparticles for triggering apoptosis in human leukemia cancer cells

Energy Technology Data Exchange (ETDEWEB)

Say, R Latin-Small-Letter-Dotless-I dvan, E-mail: rsay@anadolu.edu.tr [Anadolu Universitesi, Kimya Boeluemue, Fen Fakueltesi (Turkey); Yazar, Suzan [Sanovel Pharmaceutical Company (Turkey); Ugur, Alper; Huer, Deniz [Anadolu Universitesi, Kimya Boeluemue, Fen Fakueltesi (Turkey); Denizli, Adil [Hacettepe University, Department of Chemistry (Turkey); Ersoez, Arzu [Anadolu Universitesi, Kimya Boeluemue, Fen Fakueltesi (Turkey)

2013-01-15

Integrin family members are the main mediators of cell adhesion to the extracellular matrix and active as intra- and extracellular signaling molecules in a variety of processes. They bind to their ligands by interacting with short amino acid sequences, that is, RGD (arginine-glycine-aspartic acid) sequence. RGD sequences have been used to enhance cell binding to artificial surfaces, so RGD mimics have been used to block integrin binding to its ligand. Integrin-ligand interactions are dependent on divalent cations, and Mg{sup 2+} provide higher-affinity binding to ligand for many integrins. In this study, we have designed new integrin antagonists using methacryloyl amidoaspartic acid (MAASP) monomer-conjugated silanized super paramagnetic iron oxide nanoparticles (SPIONs, the size of the nanoparticles was verified with an average size of 32.6 nm) and poly(MAASP-co-EDMA) shell-decorated silanized SPIONs. Several mechanisms have been proposed to describe uptake of modified SPIONs into the cells, including receptor-mediated endocytosis. Our aim is to bind these modified SPIONs to the integrin-mediated aspartic acid ends of MAASP monomers and block integrin binding to their ligand.

Combinatorial and high-throughput screening of the effect of siloxane composition on the surface properties of crosslinked siloxane-polyurethane coatings.

Science.gov (United States)

Ekin, Abdullah; Webster, Dean C

2007-01-01

Libraries of siloxane-polyurethane coatings were designed, formulated, and screened using high-throughput experimentation. Four independent variables that were analyzed were the molecular weight of poly(dimethylsiloxane) (PDMS), presence or absence of poly(epsilon-caprolactone) (PCL) blocks attached to the PDMS backbone, the length of the PCL blocks, and the siloxane polymer level in the coating formulations. In addition to the siloxane libraries (3-aminopropyl-terminated PDMS and poly(epsilon-caprolactone)-poly(dimethylsiloxane)-poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers), the coating formulation included a trifunctional isocyanate crosslinker, trifunctional poly(epsilon-caprolactone) polyol, 2,4-pentanedione (pot-life extender), dibutyltin diacetate (catalyst), and a blend of solvents. The resulting coatings were analyzed for their surface energy and pseudobarnacle adhesion both before and after aging the coatings for 30 days in water. The water and methylene iodide contact angle averages increase with increasing molecular weight of PDMS. Coatings prepared from PCL-PDMS-PCL triblock copolymers have lower surface energies than coatings prepared from 3-aminopropyl-terminated PDMS; however, lower pseudobarnacle adhesion results were obtained for the coatings prepared from 3-aminopropyl-terminated PDMS than coatings prepared from PCL-PDMS-PCL triblock copolymers. The siloxane polymer level in the coating formulations does not have a significant effect on the surface energy of the coatings, but it resulted in higher pseudobarnacle adhesion.

Oxygen reduction reaction catalysts of manganese oxide decorated by silver nanoparticles for aluminum-air batteries

International Nuclear Information System (INIS)

Sun, Shanshan; Miao, He; Xue, Yejian; Wang, Qin; Li, Shihua; Liu, Zhaoping

2016-01-01

In this paper, the hybrid catalysts of manganese oxide decorated by silver nanoparticles (Ag-MnO x ) are fully investigated and show the excellent oxygen reduction reaction (ORR) activity. The Ag-MnO 2 is synthesized by a facile strategy of the electroless plating of silver on the manganese oxide. The catalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Then, the ORR activities of the catalysts are systematically investigated by the rotating disk electrode (RDE) and aluminum-air battery technologies. The Ag nanoparticles with the diameters at about 10 nm are anchored on the surface of α-MnO 2 and a strong interaction between Ag and MnO 2 components in the hybrid catalyst are confirmed. The electrochemical tests show that the activity and stability of the 50%Ag-MnO 2 composite catalyst (the mass ratio of Ag/MnO 2 is 1:1) toward ORR are greatly enhanced comparing with single Ag or MnO 2 catalyst. Moreover, the peak power density of the aluminum-air battery with 50%Ag-MnO 2 can reach 204 mW cm −2 .

Synergistic effect of Ag nanoparticle-decorated graphene oxide and carbon fiber on electrical actuation of polymeric shape memory nanocomposites

International Nuclear Information System (INIS)

Lu, Haibao; Leng, Jinsong; Du, Shanyi; Liang, Fei; Gou, Jihua

2014-01-01

This study reports an effective approach of significantly improving electrical properties and recovery performance of shape memory polymer (SMP) nanocomposite, of which its shape recovery was triggered by electrically resistive Joule heating. Reduced graphene oxide (GOs) self-assembled and grafted onto carbon fiber, were used to enhance the interfacial bonding with the SMP matrix via van der Waals force and covalent bond, respectively. A layer of Ag nanoparticles was synthesized from Ag + solution and chemically deposited onto GO assemblies. These Ag nanoparticles were expected to bridge the gap between GO and improve the electrical conductivity. The experimental results reveal that the electrical conductivity of the SMP nanocomposite was significantly improved via the synergistic effect between Ag nanoparticle-decorated GO and carbon fiber. Finally, the electrically induced shape memory effect of the SMP nanocomposite was achieved, and the temperature distribution in the SMP nanocomposites was recorded and monitored. An effective approach was demonstrated to produce the electro-activated SMP nanocomposites and the resistive Joule heating was viable at a low electrical voltage below 10 V. (paper)

W18O49 nanorods decorated with Ag/AgCl nanoparticles as highly-sensitive gas-sensing material and visible-light-driven photocatalyst

International Nuclear Information System (INIS)

Sun Shibin; Chang Xueting; Dong Lihua; Zhang Yidong; Li Zhenjiang; Qiu Yanyan

2011-01-01

A novel gas-sensing material and photocatalyst was successfully obtained by decorating Ag/AgCl nanoparticles on the W 18 O 49 nanorods through a clean photochemical route. The as-prepared samples were characterized using combined techniques of X-ray diffractometry, electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Gas-sensing measurements indicate that the Ag/AgCl/W 18 O 49 NRs sensors exhibit superior reducing gas-sensing properties to those of bare W 18 O 49 NRs, and they are highly selective and sensitive to NH 3 , acetone, and H 2 S with short response and recovery times. The Ag/AgCl/W 18 O 49 NRs photocatlysts also possess higher photocatalytic performance than bare W 18 O 49 NRs for degradation of methyl orange under simulated sunlight irradiation. Possible mechanisms concerning the enhancement of gas-sensing and photocatalytic activities of the Ag/AgCl/W 18 O 49 NRs composite were proposed. - Graphical Abstract: The Ag/AgCl nanoparticles adhered well to the W 18 O 49 nanorod. The Ag could act as transfer center of the photoexcited carriers, prohibiting their recombinations in both W 18 O 49 and AgCl. Highlights: → Ag/AgCl/W 18 O 49 NRs were successfully obtained via a clean photochemical route. → The Ag/AgCl nanoparticles decorated on the W 18 O 49 NRs possessed cladding structure. → The Ag/AgCl/W 18 O 49 NRs exhibited excellent gas-sensing and photocatalytic properties.

Evaluation of bonding between oxygen plasma treated polydimethyl siloxane and passivated silicon

Energy Technology Data Exchange (ETDEWEB)

Tang, K C [Bioelectronics/BioMEMS Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore); Liao, E [Semiconductor Process Technologies Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore); Ong, W L [Bioelectronics/BioMEMS Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore); Wong, J D S [Semiconductor Process Technologies Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore); Agarwal, A [Bioelectronics/BioMEMS Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore); Nagarajan, R [Semiconductor Process Technologies Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore); Yobas, L [Bioelectronics/BioMEMS Laboratory, Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore)

2006-04-01

Oxygen plasma treatment has been used extensively to bond polydimethyl siloxane to polydimethyl siloxane or glass in the rapid prototyping of microfluidic devices. This study aimed to improve the bonding quality of polydimethyl siloxane to passivated silicon using oxygen plasma treatment, and also to evaluate the bonding quality. Four types of passivated silicon were used: phosphosilicate glass, undoped silicate glass, silicon nitride and thermally grown silicon dioxide. Bonding strength was evaluated qualitatively and quantitatively using manual peel and mechanical shear tests respectively. Through peel tests we found that the lowering of plasma pressure from 500 to 30 mTorr and using a plasma power between 20 to 60 W helped to improve the bond quality for the first three types of passivation. Detailed analysis and discussion were conducted to explain the discrepancy between the bonding strength results and peeling results. Our results suggested that polydimethyl siloxane can be effectively bonded to passivated silicon, just as to polydimethyl siloxane or glass.

Synthesis of Siloxanes Directly from Amorphous Silica

International Nuclear Information System (INIS)

Myint Sandar Win

2011-12-01

A direct synthesis of oligomeric-siloxanes from amorphous silica has been achieved. The compound prepared was caedonal-siloxane. Cardonal is a mono hydroxyphenolic compound with a bulky group in the meta position. It was derived as a by-product from the renewable resources cashew nut shell liquid (CNSL). In the synthesis, one pot synthesis was carried out by using ethylene glycol (EG) as solvent. In the reaction ethylene glycol served as a primary precursor chelating ligand in the synthesised product. The one pot synthesis was enhanced by the strong base, triethylenetetramine (TETA) which served as the promoter catalyst. In the synthesis, optimal conditions were established on the basic of the yield percent of organo-siloxane compounds with respect to the variation of the weight fraction of TETA and to the variation of reaction time. Experimental runs were carried out at (ca 210 2c) which was nearly above the boiling point of the solvent. The substituted organo-silicon compounds obtained were characterized by FT- ir, Thermal analysis, XRD and SEM.

Gelatin-Based Films and Coatings for Food Packaging Applications

Directory of Open Access Journals (Sweden)

Marina Ramos

2016-09-01

Full Text Available This review discusses the latest advances in the composition of gelatin-based edible films and coatings, including nanoparticle addition, and their properties are reviewed along their potential for application in the food packaging industry. Gelatin is an important biopolymer derived from collagen and is extensively used by various industries because of its technological and functional properties. Nowadays, a very wide range of components are available to be included as additives to improve its properties, as well as its applications and future potential. Antimicrobials, antioxidants and other agents are detailed due to the fact that an increasing awareness among consumers regarding healthy lifestyle has promoted research into novel techniques and additives to prolong the shelf life of food products. Thanks to its ability to improve global food quality, gelatin has been particularly considered in food preservation of meat and fish products, among others.

Synthesis, characterization and magnetic properties of MWCNTs decorated with Zn-substituted MnFe{sub 2}O{sub 4} nanoparticles using waste batteries extract

Energy Technology Data Exchange (ETDEWEB)

Gabal, M.A., E-mail: mgabalabdonada@yahoo.com [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Al-Harthy, E.A. [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80216, Jeddah 21589 (Saudi Arabia); Al Angari, Y.M.; Abdel Salam, M.; Asiri, A.M. [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia)

2016-06-01

Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.2–0.8) nano-crystals, synthesized from recycling of Zn–C batteries, were successfully self-assembled alongside multi-walled carbon nanotubes (MWCNTs) via an environmentally friend sucrose auto-combustion method. The effect of Zn-content on structural and magnetic properties were investigated and discussed. XRD revealed the formation of single-phase ferrites. DTA–TG experiment showed that the auto-combustion reaction finished at about 350 {sup °}C. TEM exhibited that the MWCNTs are well decorated with ferrite particles. Hysteresis loop measurements revealed ferromagnetic behavior, with saturation magnetization decrease by the addition of MWCNTs or increasing Zn-Content. The kinetics of methylene blue dye (MB) removal using MWCNTs/Mn{sub 0.8}Zn{sub 0.2}Fe{sub 2}O nano-composite was investigated and discussed. - Graphical abstract: TEM image of MWCNTs/Mn{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nano-composite showed that the MWCNTs were completely decorated with magnetic nanoparticles. The decoration passed through nucleation and growth processes in which nucleation of ferrite nanoparticles first takes place on the surface of MWCNTs followed by a subsequent growth of these nuclei. - Highlights: • Mn-Zn-ferrites were obtained via recycling process of spent Zn-C batteries. • Mn1−xZnxFe2O4/MWCNTS nano-composites were synthesized via sucrose combustion route. • Zn-substitution effect on structural and magnetic properties was investigated. • MWCNTs/Mn0.8Zn0.2Fe2O4 was investigated to remove MB dye from aqueous media.

A novel non-enzymatic H2O2 sensor based on polypyrrole nanofibers-silver nanoparticles decorated reduced graphene oxide nano composites

Science.gov (United States)

Moozarm Nia, Pooria; Lorestani, Farnaz; Meng, Woi Pei; Alias, Y.

2015-03-01

Graphene oxide (GO) decorated with silver nanoparticles (AgNPs), was electrochemically reduced on glassy carbon electrode (GCE) by an amperometry method (AMP-AgNPs-rGO/GCE). Then, Pyrrole was electropolymerized on the surface of the modified electrode through amperometry process in order to obtain nanofibers of polypyrrole (AMP-PpyNFs-AgNPs-rGO). Fourier-transform infrared transmission spectroscopy and X-ray diffraction approved that during the amperometry process, the GO and Ppy nanofibers were reduced and polymerized respectively and the silver nanoparticles were formed. Field emission scanning electron microscope images indicated that the silver nanoparticles were homogeneously distributed on the rGO surface with a narrow nano size distribution and polypyrrole synthesized in the form of nanofibers with diameter around 100 nm. The first linear section was in the range of 0.1-5 mM with a limit of detection of 1.099 and the second linear section raised to 90 mM with a correlation factor of 0.085 (S/N of 3)

Decoration of Multi-walled Carbon Nanotubes by Metal ...

African Journals Online (AJOL)

The powder patterns of the as-prepared and acid treated MWCNTs are shown by the XRD spectra. The TEM results show the microstructure of the multi-walled carbon nanotubes well decorated with metal nanoparticles (Cu, Fe, Ni) and metal oxides (CuO, Fe2O3, NiO), while the SEM show the surface morphology.

Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives.

Science.gov (United States)

Ge, Xueping; Ye, Qiang; Song, Linyong; Misra, Anil; Spencer, Paulette

2014-09-01

The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties. Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA, 45/55, w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA). The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt% water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption. The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives. Published by Elsevier Ltd.

Photochemical decoration of gold nanoparticles on polymer stabilized magnetic microspheres for determination of adenine by surface-enhanced Raman spectroscopy

International Nuclear Information System (INIS)

Alula, Melisew Tadele; Yang, Jyisy

2015-01-01

Magnetic microspheres decorated with gold nanoparticles (AuNPs) were prepared and used for the determination of adenine by surface-enhanced Raman scattering (SERS). Magnetic particles were first synthesized by coprecipitation of solutions containing iron(II) and iron(III) ions with ammonium hydroxide. Subsequently, the magnetic particles were suspended into a solution of poly(divinylbenzene-co-methyl methacrylate) to yield polymer-stabilized magnetic microspheres. These were further decorated with AuNPs via a new photochemical reduction method. The magnetic microspheres were characterized by XRD patterns and SEM images. They are shown to represent highly SERS-active substrates by giving an enhancement by almost 7 orders of magnitude compared to conventional Raman spectroscopy. Several factors that affect the photochemical reduction to form the AuNPs were examined. It is found that the concentration of gold ion, UV irradiation time, and citrate concentration have more impact on the reaction rate than on the morphologies of the AuNPs. The gold-decorated magnetic microspheres are highly stable in aqueous solution and capable of concentrating nucleobases. A linear response of the SERS signal to adenine in concentrations up to 10 μM is found, with a linear regression coefficient of 0.997. The detection limit is estimated to a few hundreds of nM (at an SNR of 3). Based on its specific Raman peak at 734 cm −1 , adenine can be selectively determined without interference by other nucleobases, and a recovery higher than 95 % could be obtained. (author)

Three-dimensional nanoporous MoS2 framework decorated with Au nanoparticles for surface-enhanced Raman scattering

Science.gov (United States)

Sheng, Yingqiang; Jiang, Shouzhen; Yang, Cheng; Liu, Mei; Liu, Aihua; Zhang, Chao; Li, Zhen; Huo, Yanyan; Wang, Minghong; Man, Baoyuan

2017-08-01

The three-dimensional (3D) MoS2 decorated with Au nanoparticles (Au NPs) hybrids (3D MoS2-Au NPs) for surface-enhanced Raman scattering (SERS) sensing was demonstrated in this paper. SEM, Raman spectroscopy, TEM, SAED, EDX and XRD were performed to characterize 3D MoS2-Au NPs hybrids. Rhodamine 6G (R6G), fluorescein and gallic acid molecules were used as the probe for the SERS detection of the 3D MoS2-Au NPs hybrids. In addition, we modeled the enhancement of the electric field of MoS2-Au NPs hybrids using Finite-difference time-domain (FDTD) analysis, which can further give assistance to the mechanism understanding of the SERS activity.

Preparation and Characterization of Astaxanthin Nanoparticles by Solvent-Diffusion Technique

International Nuclear Information System (INIS)

Anarjan, N.; Tan, C.P.

2011-01-01

In this work, astaxanthin nanoparticles were prepared in aqueous media using solvent-diffusion technique. Sodium caseinate, gelatin, Polysorbate 20 and gum Arabic were selected as different food grade surface active molecules for the stabilization of the produced nanoparticles. Results showed that among produced astaxanthin nanoparticles, the Polysorbate 20-stabilized nanoparticles showed the smallest particle size; gum Arabic-stabilized nanoparticles had the smallest polydispersity index and highest physical stability in simulated gastric fluid (SGF); and those stabilized using gelatin had the highest zeta potential. Sodium caseinate stabilized nanoparticles had the highest astaxanthin content in fresh samples as compared to other prepared nano dispersions. (author)

Transplantation of artificial gelatin-co-bletillastriata gelatin/ Salvia ...

African Journals Online (AJOL)

Purpose: To evaluate the growth of the composite corium (constructed with fibroblast cells and gelatinco- Bletillastriata gelatin/Salvia miltiorrhiza materials) on rats. Methods: The composite artificial corium was constructed by culturing fibroblast cells in gelatin-co- Bletillastriata gelatin/Salvia miltiorrhiza materials.

Direct synthesis of mesostructured carbon nanofibers decorated with silver-nanoparticles as a multifunctional membrane for water treatment

International Nuclear Information System (INIS)

Taha, Ahmed Aboueloyoun

2015-01-01

One-dimensional (1D) porous carbon nanofibers (CNFs) decorated by silver (Ag) nanoparticles (NPs) were prepared using a one-pot/self-template synthesis strategy by combining electrospinning and carbonization methods. The characterization results revealed that AgNPs were homogenously distributed along the CNFs and possessed a relatively uniform nano-size of about 12 nm. The novel membrane distinctively displayed enhanced photocatalytic activity under visible-light irradiation. The membrane exhibited excellent dye degradation and bacteria disinfection in batch experiments. The high photocatalytic activity can be attributed to the highly accessible surface areas, good light absorption capability, and high separation efficiency of photogenerated electron–hole pairs. The as-prepared membranes can be easily recycled because of their 1D property. (paper)

Bimetallic Ag-Pd nanoparticles-decorated graphene oxide: a fascinating three-dimensional nanohybrid as an efficient electrochemical sensing platform for vanillin determination

International Nuclear Information System (INIS)

Li, Junhua; Feng, Haibo; Li, Jun; Jiang, Jianbo; Feng, Yonglan; He, Lingzhi; Qian, Dong

2015-01-01

Highlights: • A 3D Ag-Pd/GO nanohybrid was fabricated via a green and in situ chemical route. • Ag-Pd/GO shows excellent electro-catalytic properties for the oxidation of vanillin. • The 3D hybrid-based sensor shows excellent performances for the vanillin detection. • This proposed method was successfully used to detect vanillin in children’s snacks. - Abstract: In this work, a fascinating hybrid based on Ag-Pd bimetallic nanoparticles-decorated graphene oxide (Ag-Pd/GO) has been successfully synthesized by a green and in situ chemical reduction strategy. The resultant hybrid was particularly characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible spectroscopy and electrochemical techniques. The morphological results illustrate that Ag-Pd nanoparticles in microspheric appearances are highly dispersed and embedded on the GO layers, resulting in a rough surface and three-dimensional (3D) microstructure with a high Ag-Pd content in the matrix. The as-synthesized 3D Ag-Pd/GO hybrid displays distinctly enhanced electrocatalytic activity for the vanillin oxidation in comparison with that of the monometal-decorated GO, revealing a synergistic effect of the matrix GO and the doped bimetallic Ag-Pd. Therefore, the Ag-Pd/GO composite can be used as an enhanced electrochemical sensing platform for the sensitive determination of vanillin, and the fabricated sensor displays a wide detection range of 0.02–45 μmol dm −3 , low detection limit of 5 nmol dm −3 and satisfactory recoveries between 98.8 % and 103.5 %. All the results demonstrate that the 3D hybrids integrated graphene with bimetallic nanoparticles are promising candidates for the development of high-performance electrochemical sensors

Electrospun Magnetic Nanoparticle-Decorated Nanofiber Filter and Its Applications to High-Efficiency Air Filtration.

Science.gov (United States)

Kim, Juyoung; Chan Hong, Seung; Bae, Gwi Nam; Jung, Jae Hee

2017-10-17

Filtration technology has been widely studied due to concerns about exposure to airborne dust, including metal oxide nanoparticles, which cause serious health problems. The aim of these studies has been to develop mechanisms for the continuous and efficient removal of metal oxide dusts. In this study, we introduce a novel air filtration system based on the magnetic attraction force. The filtration system is composed of a magnetic nanoparticle (MNP)-decorated nanofiber (MNP-NF) filter. Using a simple electrospinning system, we fabricated continuous and smooth electrospun nanofibers with evenly distributed Fe 3 O 4 MNPs. Our electrospun MNP-NF filter exhibited high particle collection efficiency (∼97% at 300 nm particle size) compared to the control filter (w/o MNPs, ∼ 68%), with a ∼ 64% lower pressure drop (∼17 Pa) than the control filter (∼27 Pa). Finally, the filter quality factors of the MNP-NF filter were 4.7 and 11.9 times larger than those of the control filter and the conventional high-efficiency particulate air filters (>99% and ∼269 Pa), respectively. Furthermore, we successfully performed a field test of our MNP-NF filter using dust from a subway station tunnel. This work suggests that our novel MNP-NF filter can be used to facilitate effective protection against hazardous metal oxide dust in real environments.

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

Science.gov (United States)

Meng, Yuan; Su, Fenghua; Chen, Yangzhi

2016-08-01

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

Cationic Gelatin Nanoparticles for Drug Delivery to the Ocular Surface: In Vitro and In Vivo Evaluation

Directory of Open Access Journals (Sweden)

Ching-Li Tseng

2013-01-01

Full Text Available To develop an effective ocular drug delivery carrier, we prepared two different charged gelatin nanoparticles (GPs and evaluated particle size, surface charge, and morphology. The in vitro biocompatibility of GPs was assessed using human corneal epithelium (HCE cells and in vivo safety by administering them as eye drops to New Zealand rabbits. The GPs prepared using type A gelatin were positively charged (GP(+, +33 mV; size, 180.6±45.7 nm. Water-soluble tetrazolium salt (WST-1 assay showed that both GPs were nontoxic to HCE cells. The fluorescence intensity of HCE cells cultured with cationic GPs conjugated with a fluorescent dye was higher than that of the anionic GP-treated HCE cells. In vivo examination showed no serious irritation to the rabbit eyes. Furthermore, corneal thickness and ocular pressure in the eyes of the treated rabbits were similar to those in the eyes of normal rabbits. Microscopic examination of corneal cryosections showed widely distributed fluorescent nanocarriers, from the anterior to the posterior part of the cornea of the GP(+ group, and higher fluorescence intensity in the GP(+ group was also observed. In conclusion, GPs as cationic colloidal carriers were efficiently adsorbed on the negatively charged cornea without irritating the eyes of the rabbits and can be retained in the cornea for a longer time. Thus, GPs(+ have a great potential as vehicles for ocular drug delivery.

Synthesis of hybrid polymers of beta-Cd and siloxanes

International Nuclear Information System (INIS)

Abbehausen, Camilla; Yoshida, Inez V.P.

2009-01-01

Hybrid polymers derived from siloxane and β-cyclodextrin (β-CD) were obtained from gamma-isocyanate-propyl-triethoxy-silane (IPTS) and β-CD. The resulting alkoxysilane was hydrolyzed generating glassy β-CD modified polysilsesquioxane. The alkoxysilane was also submitted to condensation with poly(dimethylsiloxane) with - Si(CH 3 -) 2 -OH end groups, giving rise to a polymeric network with β-CD at crosslinking nodes. These materials were characterized by infrared spectrum, 13 C and 29 Si nuclear magnetic resonance and X ray diffraction. The thermal behavior was analyzed by thermogravimetry. The capability of β-CD grafted in the siloxane polymers to form inclusion complexes was evaluated by the formation of β-CD-phenolphthalein complex, by UV-vis spectrum. The ability of water diffusion into β-CD-PSS film was evaluated by swollen measurement. β-CD-modified siloxanes were able to form films and their morphologies were evaluated by scanning electron microscopy. (author)

Lanthanum doped titania decorated with silver plasmonic nanoparticles with enhanced photocatalytic activity under UV-visible light

Science.gov (United States)

Dal'Toé, Adrieli T. O.; Colpani, Gustavo Lopes; Padoin, Natan; Fiori, Márcio Antônio; Soares, Cíntia

2018-05-01

Lanthanum doped titanium dioxide decorated with silver plasmonic nanoparticles (Ag-La/TiO2 NPs) materials were prepared using a simple ultrasound-assisted wet impregnation method followed by silver photodeposition. The obtained photocatalysts with different Ag contents were characterized by XRD, FE-SEM, EDX, TEM, BET, XPS, DRS and PL techniques. Moreover, the size distribution of the nanoparticles aggregates was assessed. The characterization analysis revealed that La doping slightly changed the crystalline phase of TiO2, increased the amount of surface hydroxyl groups and interacted with TiO2 nanoparticles via Ti-O-La bond, while Ag photodeposition enhanced the absorption of visible light due to the effects of localized surface plamon resonance and significantly decreased electronic recombination rate by the Schottky junction. Furthermore, the combination of Ag-La induced the formation of oxygen vacancies, which increased the amount of adsorbed surface hydroxyl groups in Ag-La/TiO2. In addition, Ag-La possibly decreased the semiconductor surface energy, which acted positively in the reduction of NPs aggregation. These features along with better textural properties (greater surface areas) played a fundamental role in the enhancement of the photocatalytic activity of Ag-La/TiO2 composites for the decolorization of methylene blue under UV-visible irradiation compared to the mono-metallic (La/TiO2 and Ag/TiO2) modified photocatalysts. Finally, a mechanism for the transfer of charge carriers in Ag-La/TiO2 photocatalyst under UV-visible irradiation was proposed.

Preparation and antibacterial property of silver decorated carbon microspheres

International Nuclear Information System (INIS)

Li, Sha; Yan, Xiaoliang; Yang, Zhi; Yang, Yongzhen; Liu, Xuguang; Zou, Jing

2014-01-01

Carbon microspheres (CMSs) were prepared by glucose hydrothermal method. The effects of glucose concentration and reaction time on the size and morphology of CMSs were studied. CMSs with surface area of 642.5 m 2 /g and pore size of 0.8 nm were exploited to design hybrid material of CMSs with Ag decoration by radio frequency plasma (RF plasma). A series of investigations using X-ray diffraction, UV–vis spectrometry, Fourier transform infrared spectrometry, X-ray photoelectron spectrometry, thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy was carried out to characterize the Ag decorated CMSs. RF plasma was employed to reduce Ag + ions to metallic nano-particles with the particle size of 10–20 nm and form a clean metal-support (Ag-CMSs) interface. The mechanism for the structure formation of Ag decorated CMSs was discussed. Plasma produced Ag/CMSs showed antibacterial property and proved suitable for potential biological and environmental applications.

Detecting decompositions of sulfur hexafluoride using reduced graphene oxide decorated with Pt nanoparticles

Science.gov (United States)

Chen, Dachang; Tang, Ju; Zhang, Xiaoxing; Fang, Jiani; Li, Yi; Zhuo, Ran

2018-05-01

The resistance-typed gas sensing material of Pt nanoparticles (PtNPs) decorated reduced graphene oxide (RGO) synthesized by one-step chemical reduction for the detection of four types of SF6 decompositions was explored. The PtNPs disperse uniformly on RGO with particle size near 2–4 nm and a small number of particles are larger than 10 nm. Gas sensing tests suggest that the introduction of PtNPs increases the response to SO2, SOF2 and H2S compared to pure RGO and PtNPs-RGO experiences resistance reducing in SO2 and SOF2 while presenting the opposite case in H2S. Elevating the temperature enhances the recovery properties to SO2 and H2S but lowers the sensitivity. The sensing mechanism for Pt-RGO in low oxygen and water environment depends mainly on the charge transfer between gas and adsorbent and the solvent on material surface. The work provides experimental investigation of Pt-RGO to detect SF6 decompositions.

Preparation, characterization, and antibacterial activity of silver nanoparticle-decorated graphene oxide nanocomposite.

Science.gov (United States)

Shao, Wei; Liu, Xiufeng; Min, Huihua; Dong, Guanghui; Feng, Qingyuan; Zuo, Songlin

2015-04-01

In this work, we report a facile and green approach to prepare a uniform silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite (GO-Ag). The nanocomposite was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, and X-ray photoelectron spectroscopy (XPS), which demonstrated that AgNPs with a diameter of approximately 22 nm were uniformly and compactly deposited on GO. To investigate the silver ion release behaviors, HEPES buffers with different pH (5.5, 7, and 8.5) were selected and the mechanism of release actions was discussed in detail. The cytotoxicity of GO-Ag nanocomposite was also studied using HEK 293 cells. GO-Ag nanocomposite displayed good cytocompatibility. Furthermore, the antibacterial properties of GO-Ag nanocomposite were studied using Gram-negative E. coli ATCC 25922 and Gram-positive S. aureus ATCC 6538 by both the plate count method and disk diffusion method. The nanocomposite showed excellent antibacterial activity. These results demonstrated that GO-Ag nanocomposite, as a kind of antibacterial material, had a great promise for application in a wide range of biomedical applications.

Substrate decoration for improvement of current-carrying capabilities of YBa{sub 2}Cu{sub 3}O{sub x} thin films

Energy Technology Data Exchange (ETDEWEB)

Khoryushin, Alexey V., E-mail: khoryushin@ya.ru [Department of Physics, Technical University of Denmark, DTU Building 309, Kgs. Lyngby DK-2800 (Denmark); Mozhaev, Peter B.; Mozhaeva, Julia E. [Department of Physics, Technical University of Denmark, DTU Building 309, Kgs. Lyngby DK-2800 (Denmark); Bdikin, Igor K. [Department of Mechanical Engineering, Centre for Mechanical Technology and Automation, University of Aveiro, 3810-193 Aveiro (Portugal); Zhao, Yue [Department of Energy Conversion and Storage, Technical University of Denmark, DK-4000 Roskilde (Denmark); Andersen, Niels H.; Jacobsen, Claus S.; Hansen, Jørn Bindslev [Department of Physics, Technical University of Denmark, DTU Building 309, Kgs. Lyngby DK-2800 (Denmark)

2013-03-15

Highlights: ► Effects of substrate decoration on properties of YBCO thin films were studied. ► Y{sub 2}O{sub 3} nanoparticles, ultra-thin Y{sub 2}O{sub 3} and Y:ZrO{sub 2} layers were used as decoration layer. ► Decoration improves j{sub C} (5 T and 50 K) up to 0.97 MA/cm{sup 2} vs. 0.76 MA/cm{sup 2} for a reference film. ► Ultra-thin layer of yttria and yttria nanoparticles have a similar effect on YBCO. ► Y{sub 2}O{sub 3} decoration results in power law coefficient α = 0.3 vs. α = 0.4 for a reference film. -- Abstract: The effects of substrate decoration with yttria and Y:ZrO{sub 2} on the structural and electrical properties of the YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) thin films are studied. The films were deposited on (LaAlO{sub 3}){sub 3}–(Sr{sub 2}AlTaO{sub 8}){sub 7} substrates by pulsed laser deposition. Two different structures of decoration layer were applied, a template layer of nanoparticles and an uniform ultra-thin layer. Significant improvement of current-carrying capabilities was observed, especially at high external magnetic fields. Structural studies of these films reveal the presence of extended linear defects in the YBCO matrix. The formation of these structures is attributed to seeding of randomly oriented YBCO grains due to suppression of epitaxy in the very beginning of the deposition. The films of both kinds of decoration layers show nearly the same improvement of j{sub C} over the reference film at 77 and 50 K: j{sub C} (5T and 50 K) reaches 0.92 and 0.97 MA/cm{sup 2} for uniform and template decoration layers. At 5 and 20 K the effect of template decoration layers is more beneficial: j{sub C} (5T and 20 K) values are 3.5 and 4.1 MA/cm{sup 2}, j{sub C} (5T and 5 K) values are 6.4 and 7.9 MA/cm{sup 2}, for uniform and template decoration layers, respectively.

Radiation as a processing aid for upgrading gelatin and gelatin capsules

International Nuclear Information System (INIS)

Patel, K.M.; Tantry, M.; Sharma, G.; Gopal, N.G.S.

1979-01-01

Gelatin for pharmaceutical use should not contain more than 1000 microorganisms per gram and must not contain pathogenic microorganisms like Salmonella species and E.Coli. For some biological studies spore free gelatin is essential. Locally available gelatin and gelatin capsules have been found to contain a good number of microorganisms. Gelatin and its capsules containing different colours were exposed to graded doses of radiation and stored at different temperatures. They were then examined for microbial content, disintegration characteristics, pH, viscosity and colour change. The study shows that radiation treatment is useful to upgrade microbiologically both gelatin and its capsules. This technique provides apparently a useful and economic method for producing spore free gelatin which in commerce is relatively expensive. (auth.)

Radiation as a processing aid for upgrading gelatin and gelatin capsules

Energy Technology Data Exchange (ETDEWEB)

Patel, K M; Tantry, M; Sharma, G; Gopal, N G.S. [Bhabha Atomic Research Centre, Bombay (India). ISOMED

1979-01-01

Gelatin for pharmaceutical use should not contain more than 1000 microorganisms per gram and must not contain pathogenic microorganisms like Salmonella species and E.Coli. For some biological studies spore free gelatin is essential. Locally available gelatin and gelatin capsules have been found to contain a good number of microorganisms. Gelatin and its capsules containing different colours were exposed to graded doses of radiation and stored at different temperatures. They were then examined for microbial content, disintegration characteristics, pH, viscosity and colour change. The study shows that radiation treatment is useful to upgrade microbiologically both gelatin and its capsules. This technique provides apparently a useful and economic method for producing spore free gelatin which in commerce is relatively expensive.

Polydimethyl siloxane based nanocomposites with antibiofilm properties for biomedical applications.

Science.gov (United States)

Sankar, G Gomathi; Murthy, P Sriyutha; Das, Arindam; Sathya, S; Nankar, Rakesh; Venugopalan, V P; Doble, Mukesh

2017-07-01

Polydimethyl siloxane (PDMS) is an excellent implant material for biomedical applications, but often fails as it is prone to microbial colonization which forms biofilms. In the present study CuO, CTAB capped CuO, and ZnO nanoparticles were tested as nanofillers to enhance the antibiofilm property of PDMS against Staphylococcus aureus and Escherichia coli. In general S. aurues (Gram positive and more hydrophobic) favor PDMS surface than glass while E. coli (Gram negative and more hydrophilic) behaves in a reverse way. Incorporation of nanofillers renders the PDMS surface antibacterial and reduces the attachment of both bacteria. These surfaces are also not cytotoxic nor show any cell damage. Contact angle of the material and the cell surface hydrophobicity influenced the extent of bacterial attachment. Cell viability in biofilms was dependent on the antimicrobial property of the nanoparticles incorporated in the PDMS matrix. Simple regression relationships were able to predict the bacterial attachment and number of dead cells on these nanocomposites. Among the nanocomposites tested, PDMS incorporated with CTAB (cetyl trimethylammonium bromide)-capped CuO appears to be the best antibacterial material with good cyto-compatibility. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1075-1082, 2017. © 2016 Wiley Periodicals, Inc.

Selectivity and limitations of carbon sorption tubes for capturing siloxanes in biogas during field sampling.

Science.gov (United States)

Tansel, Berrin; Surita, Sharon C

2016-06-01

Siloxane levels in biogas can jeopardize the warranties of the engines used at the biogas to energy facilities. The chemical structure of siloxanes consists of silicon and oxygen atoms, alternating in position, with hydrocarbon groups attached to the silicon side chain. Siloxanes can be either in cyclic (D) or linear (L) configuration and referred with a letter corresponding to their structure followed by a number corresponding to the number of silicon atoms present. When siloxanes are burned, the hydrocarbon fraction is lost and silicon is converted to silicates. The purpose of this study was to evaluate the adequacy of activated carbon gas samplers for quantitative analysis of siloxanes in biogas samples. Biogas samples were collected from a landfill and an anaerobic digester using multiple carbon sorbent tubes assembled in series. One set of samples was collected for 30min (sampling 6-L gas), and the second set was collected for 60min (sampling 12-L gas). Carbon particles were thermally desorbed and analyzed by Gas Chromatography Mass Spectrometry (GC/MS). The results showed that biogas sampling using a single tube would not adequately capture octamethyltrisiloxane (L3), hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6). Even with 4 tubes were used in series, D5 was not captured effectively. The single sorbent tube sampling method was adequate only for capturing trimethylsilanol (TMS) and hexamethyldisiloxane (L2). Affinity of siloxanes for activated carbon decreased with increasing molecular weight. Using multiple carbon sorbent tubes in series can be an appropriate method for developing a standard procedure for determining siloxane levels for low molecular weight siloxanes (up to D3). Appropriate quality assurance and quality control procedures should be developed for adequately quantifying the levels of the higher molecular weight siloxanes in biogas with sorbent tubes

Silver Nanoparticle-Decorated Shape-Memory Polystyrene Sheets as Highly Sensitive Surface-Enhanced Raman Scattering Substrates with a Thermally Inducible Hot Spot Effect.

Science.gov (United States)

Mengesha, Zebasil Tassew; Yang, Jyisy

2016-11-15

In this study, an active surface-enhanced Raman scattering (SERS) substrate with a thermally inducible hot spot effect for sensitive measurement of Raman-active molecules was successfully fabricated from silver nanoparticle (AgNP)-decorated shape-memory polystyrene (SMP) sheets. To prepare the SERS substrate, SMP sheets were first pretreated with n-octylamine for effective decoration with AgNPs. By varying the formulation and condition of the reduction reaction, AgNP-decorated SMP (Ag@SMP) substrates were successfully prepared with optimized particle gaps to produce inducible hot spot effects on thermal shrink. High-quality SERS spectra were easily obtained with enhancement factors higher than 10 8 by probing with aromatic thiols. Several Ag@SMP substrates produced under different reaction conditions were explored for the creation of inducible hot spot effects. The results indicated that AgNP spacing is crucial for strong hot spot effects. The suitability of Ag@SMP substrates for quantification was also evaluated according to the detection of adenine. Results confirmed that prepared Ag@SMP substrates were highly suitable for quantitative analysis because they yielded an estimated limit of detection as low as 120 pg/cm 2 , a linear range of up to 7 ng/cm 2 , and a regression coefficient (R 2 ) of 0.9959. Ag@SMP substrates were highly reproducible; the average relative standard deviation for all measurements was less than 10%.

Antimicrobial effects of zinc oxide nanoparticles modified with silver

International Nuclear Information System (INIS)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes

2016-01-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Antimicrobial effects of zinc oxide nanoparticles modified with silver

Energy Technology Data Exchange (ETDEWEB)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes, E-mail: rayssasouza.net@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil)

2016-07-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Synthesis of Ag-decorated porous TiO{sub 2} nanowires through a sunlight induced reduction method and its enhanced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Yao, Yun-Chang; Dai, Xin-Rong [Anhui & Huaihe river institute of hydraulic research, Hefei, Anhui 230088 (China); Hu, Xiao-Ye, E-mail: hxy821982@issp.ac.cn [Key Laboratory of Materials Physics, and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Huang, Su-Zhen [Institute of plasma physics, Chinese Academy of Sciences, Hefei 230031 (China); Jin, Zhen, E-mail: ftbjin@hotmail.com [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

2016-11-30

Highlights: • The Ag-decorated porous TiO{sub 2} nanowires were succefully synthesized. • A sunlight induced ethanol reduction method for Ag decoration has been reported. • The Ag-decorated porous TiO{sub 2} nanowires exhibit excellent photocatalytic activity. • The photodegradation ratio of the as-prepared product is much higher than that of P25. - Abstract: In this work, Ag-decorated porous TiO{sub 2} nanowires were successfully synthesized via a facile and low-cost sunlight induced reduction method. The cooperation of sunlight irradiation and ethanol reduction results the formation and decoration of the Ag nanoparticles on the porous TiO{sub 2} nanowires. The structure of the Ag-decorated porous TiO{sub 2} nanowires were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Energy dispersive spectroscopy (EDS) measurements. It can be seen that the Ag nanoparticles are well dispersed within the porous TiO{sub 2} nanowires. The as-prepared Ag-decorated porous TiO{sub 2} nanowires exhibits excellent photocatalytic properties. The photocatalytic tests show that 10 ppm methylene blue can be photodegraded within 60 min. And the photodegradation ratio of the Ag-decorated porous TiO{sub 2} nanowires much higher than that of P25 and porous TiO{sub 2} nanowires. Moreover, the Ag-decorated porous TiO{sub 2} nanowires also reveal good photocatalytic activity towards to other organic pollutions, such as phenol and R6G. Therefore, it is believed that the Ag-decorated porous TiO{sub 2} nanowires can be used as a potential high performance photocatalyst in wastewater treatment.

Self-Supported Biocarbon-Fiber Electrode Decorated with Molybdenum Carbide Nanoparticles for Highly Active Hydrogen-Evolution Reaction.

Science.gov (United States)

Xiao, Jian; Zhang, Yan; Zhang, Zheye; Lv, Qiying; Jing, Feng; Chi, Kai; Wang, Shuai

2017-07-12

Devising and facilely synthesizing an efficient noble metal-free electrocatalyst for the acceleration of the sluggish kinetics in the hydrogen-evolution reaction (HER) is still a big challenge for electrolytic water splitting. Herein, we present a simple one-step approach for constructing self-supported biocarbon-fiber cloth decorated with molybdenum carbide nanoparticles (BCF/Mo 2 C) electrodes by a direct annealing treatment of the Mo oxyanions loaded cotton T-shirt. The Mo 2 C nanoparticles not only serve as the catalytic active sites toward the HER but also enhance the hydrophilicity and conductivity of resultant electrodes. As an integrated three-dimensional HER cathode catalyst, the BCF/Mo 2 C exhibits outstanding electrocatalytic performance with extremely low overpotentials of 88 and 115 mV to drive a current density of 20 mA cm -2 in alkaline and acidic media, respectively. In addition, it can continuously work for 50 h with little decrease in the cathodic current density in both alkaline and acidic solutions. Even better, self-supported tungsten carbide and vanadium carbide based electrodes also can be prepared by a similar synthesis process. This work will illuminate an entirely new avenue for the preparation of various self-supported three-dimensional electrodes made of transition-metal carbides for various applications.

Ni nanoparticles decorated onto graphene oxide with SiO2 as interlayer for high performance on histidine-rich protein separation

Science.gov (United States)

Yang, Xiaodan; Zhang, Min; Zheng, Jing; Li, Weizhen; Gan, Wenjun; Xu, Jingli; Hayat, Tasawar; Alharbi, Njud S.; Yang, Fan

2018-05-01

Sandwich-like structure of graphene oxide (GO) @SiO2@C-Ni nanosheets were prepared by combining an extended stöber method with subsequent carbonization treatment, in which polydopamine was used as reducing agent and carbon source. Firstly, the GO nanosheets were covered with SiO2 interlayer and finally coated with a outer shell of nickel ion doped polydopamine (PDA-Ni2+) with an extended stöber method. Followed by a carbonization to produce the GO@SiO2@C-Ni sheets with metallic nickel nanoparticles embedded in PDA-derived thin graphic carbon layer. Notably, silica interlayer played a vital role in the formation of such GO@SiO2@C-Ni sheets. Without the protection of SiO2, the hydrophobic graphene@C-Ni composites were obtained instead. While with silica layer as the spacer, the obtained hydrophilic GO@SiO2@C-Ni composites were not only well dispersed in the solution, but also can be adjusted in terms of the size and density of Ni nanoparticles (NPs) on surface by changing the calcination temperature or the molar ratio between dopamine and nickel salt. Furthermore, nickel nanoparticles decorated on GO@SiO2 sheets were employed to enrich His-rich proteins (BHb and BSA) via specific metal affinity force between polyhistidine groups and nickel nanoparticles.

Effect of ZnO decoration on the photovoltaic performance of TiO{sub 2} based dye sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Yang, Long; Zhai, Bao-gai [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China); Ma, Qing-lan [School of Electronics and Information, Nantong University, Jiangsu 226019 (China); Huang, Yuan Ming, E-mail: dongshanisland@126.com [School of Electronics and Information, Nantong University, Jiangsu 226019 (China)

2014-08-25

Highlights: • Various ZnO morphologies coated TiO{sub 2} photoanodes are formed and applied to DSSCs. • The effect of photoanode morphology on performance of DSSCs was studied. • ZnO NRs@TiO{sub 2} electrode provides more dye absorption and fast transfer pathway. • The η of DSSC with ZnO NRs@TiO{sub 2} is increased over fourfold than other DSSCs. - Abstract: ZnO nanoparticles and one-dimensional vertically aligned ZnO nanorods were grown on the TiO{sub 2} layers in the photoanodes via the hydrothermal method at 60 and 90 °C, respectively. The effect of ZnO decoration on the photovoltaic performance of TiO{sub 2} based dye sensitized solar cells (DSSCs) was investigated. The morphologies, crystalline structures and optical properties of the synthesized ZnO nanoparticles and ZnO nanorods were characterized by field-emission scanning electron microscope, X-ray diffractometer and photoluminescence spectroscopy, respectively. The photocurrent–voltage curves of the fabricated DSSCs showed that the ZnO nanorods decorated DSSCs exhibited better photovoltaic performance than the ZnO nanoparticles decorated DSSCs. The improved performance of the ZnO nanorods decorated DSSCs can be ascribed to the fact that the vertically aligned ZnO nanorods provide high specific surface area for dye adsorption and the efficient pathway for electron transportation.

Ammonia-modified graphene sheets decorated with magnetic Fe{sub 3}O{sub 4} nanoparticles for the photocatalytic and photo-Fenton degradation of phenolic compounds under sunlight irradiation

Energy Technology Data Exchange (ETDEWEB)

Boruah, Purna K. [Advanced Materials Group, Materials Sciences and Technology Division, CSIR-North East Institute of Science & Technology, Jorhat 785006 (India); Academy of Scientific and Innovative Research (AcSIR) (India); Sharma, Bhagyasmeeta [Advanced Materials Group, Materials Sciences and Technology Division, CSIR-North East Institute of Science & Technology, Jorhat 785006 (India); Karbhal, Indrapal; Shelke, Manjusha V. [Academy of Scientific and Innovative Research (AcSIR) (India); Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune-11008, Maharashtra (India); Das, Manash R., E-mail: mnshrdas@yahoo.com [Advanced Materials Group, Materials Sciences and Technology Division, CSIR-North East Institute of Science & Technology, Jorhat 785006 (India); Academy of Scientific and Innovative Research (AcSIR) (India)

2017-03-05

Highlights: • Ammonia-modified graphene sheets decorated with magnetic Fe{sub 3}O{sub 4} nanoparticles. • Photocatalytic and photo-Fenton degradation of phenolic compounds. • An excellent reusability of the nanocomposite was observed up to ten cycles. - Abstract: Synthesis of easily separable and eco-friendly efficient catalyst with both photocatalytic and photo-Fenton degradation properties is of great importance for environment remediation application. Herein, ammonia-modified graphene (AG) sheets decorated with Fe{sub 3}O{sub 4} nanoparticles (AG/Fe{sub 3}O{sub 4}) as a magnetically recoverable photocatalyst by a simple in situ solution chemistry approach. First, we have functionalized graphene oxide (GO) sheets by amide functional group and then Fe{sub 3}O{sub 4} nanoparticles (NPs) are doped onto the functionalized GO surface. The AG/Fe{sub 3}O{sub 4} nanocomposite showed efficient photocatalytic activity towards degradation of phenol (92.43%), 2-nitrophenol (2-NP) (98%) and 2-chlorophenol (2-CP) (97.15%) within 70–120 min. Consequently, in case of photo-Fenton degradation phenomenon, 93.56% phenol, 98.76% 2-NP and 98.06% of 2-CP degradation were achieved within 50–80 min using AG/Fe{sub 3}O{sub 4} nanocomposite under sunlight irradiation. The synergistic effect between amide functionalized graphene and Fe{sub 3}O{sub 4} nanoparticles (NPs) enhances the photocatalytic activity by preventing the recombination rate of electron-hole-pair in Fe{sub 3}O{sub 4} NPs. Furthermore, the remarkable reusability of the AG/Fe{sub 3}O{sub 4} nanocomposite was observed up to ten cycles during the photocatalytic degradation of these phenolic compounds.

Optical and structural properties of ensembles of colloidal Ag2S quantum dots in gelatin

International Nuclear Information System (INIS)

Ovchinnikov, O. V.; Smirnov, M. S.; Shapiro, B. I.; Shatskikh, T. S.; Perepelitsa, A. S.; Korolev, N. V.

2015-01-01

The size dependences of the absorption and luminescence spectra of ensembles of hydrophilic colloidal Ag 2 S quantum dots produced by the sol-gel method and dispersed in gelatin are analyzed. By X-ray diffraction analysis and transmission electron microscopy, the formation of core/shell nanoparticles is detected. The characteristic feature of the nanoparticles is the formation of crystalline cores, 1.5–2.0 nm in dimensions, and shells of gelatin and its complexes with the components of synthesis. The observed slight size dependence of the position of infrared photoluminescence bands (in the range 1000–1400 nm) in the ensembles of hydrophilic colloidal Ag 2 S quantum dots is explained within the context of the model of the radiative recombination of electrons localized at structural and impurity defects with free holes

In situ preparation of cobalt nanoparticles decorated in N-doped carbon nanofibers as excellent electromagnetic wave absorbers.

Science.gov (United States)

Liu, Huihui; Li, Yajing; Yuan, Mengwei; Sun, Genban; Li, Huifeng; Ma, Shulan; Liao, Qingliang; Zhang, Yue

2018-06-11

The electrospinning and annealing methods is applied to prepare cobalt nanoparticles decorated in N-doped carbon nanofibers (Co/N-C NFs) with solid and macroporous structures. In detail, the nanocomposites are synthesized by carbonization of as-electrospun polyacrylonitrile (PAN)/cobalt acetylacetonate nanofibers in an argon atmosphere. The solid Co/N-C NFs has lengths up to dozens of microns with the average diameter of ca. 500 nm and possess abundant cobalt nanoparticles on both the surface and within the fibers, and the cobalt nanoparticles size is about 20 nm. The macroporous Co/N-C NFs possess a hierarchical pore structure, and there are macropores (500 nm) and mesopores (2-50 nm) existed in this material. The saturation magnetization (Ms) and coercivity (Hc) of the solid Co/N-C NFs are 28.4 emu g-1 and 661 Oe, respectively. And those of the macroporous Co/N-C NFs are 23.3 emu g-1 and 580 Oe, respectively. The solid Co/N-C NFs exhibits excellent electromagnetic wave absorbability, a minimum reflection loss (RL) value of -25.7 dB is achieved with a matching thickness of 2 mm for solid Co/N-C NFs when the filler loading is 5 wt%, and the effective bandwidth (BW) (RL≤-10 dB) is 4.3 GHz. Moreover, the effective microwave absorption can be achieved in the whole range of 1-18 GHz by adjusting the thickness of the sample layer and content of the dopant sample.

Mussel-inspired polydopamine biopolymer decorated with magnetic nanoparticles for multiple pollutants removal

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shengxiao, E-mail: beijingzsx@163.com [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China); Zhang, Yuanyuan [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China); Bi, Guoming [Yantai Enironmental Monitoring Center, Yantai 264025, Shandong Province (China); Liu, Junshen [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China); Wang, Zhigang [Yantai Enironmental Monitoring Center, Yantai 264025, Shandong Province (China); Xu, Qiang; Xu, Hui; Li, Xiaoyan [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China)

2014-04-01

Highlights: • The Fe{sub 3}O{sub 4}/PDA hybrid material was synthesized and characterized. • The PDA polymer was firstly applied in environmental remediation. • The Fe{sub 3}O{sub 4}/PDA exhibited high adsorption capacity for multiple pollutants. • Removal efficiencies of pollutants with Fe{sub 3}O{sub 4}/PDA were pH dependent. - Abstract: The polydopamine polymer decorated with magnetic nanoparticles (Fe{sub 3}O{sub 4}/PDA) was synthesized and applied for removal of multiple pollutants. The resulted Fe{sub 3}O{sub 4}/PDA was characterized with elemental analysis, thermo-gravimetric analyses, vibrating sample magnetometer, high resolution transmission electron microscope, Fourier transform infrared spectra, and X-ray photoelectron spectroscopy. The self-polymerization of dopamine could be completed within 8 h, and Fe{sub 3}O{sub 4} nanoparticles were embedded into PDA polymer. Superparamagnetism and large saturation magnetization facilitated collection of sorbents with a magnet. Based on the catechol and amine groups, the PDA polymer provided multiple interactions to combine with pollutants. To investigate the adsorption ability of Fe{sub 3}O{sub 4}/PDA, heavy metal ions and dyes were selected as target pollutants. The adsorption of pollutants was pH dependent due to the variation of surface charges at different solution pH. The removal efficiencies of cation pollutants enhanced with solution pH increasing, and that of anion pollutant was just the opposite. Under the optimal solution pH, the maximum adsorption capacity calculated from Langmuir adsorption isotherm for methylene blue, tartrazine, Cu{sup 2+}, Ag{sup +}, and Hg{sup 2+} were 204.1, 100.0, 112.9, 259.1, and 467.3 mg g{sup −1}, respectively. The Fe{sub 3}O{sub 4}/PDA shows great potential for multiple pollutants removal, and this study is the first application of PDA polymer in environmental remediation.

Mussel-inspired polydopamine biopolymer decorated with magnetic nanoparticles for multiple pollutants removal

International Nuclear Information System (INIS)

Zhang, Shengxiao; Zhang, Yuanyuan; Bi, Guoming; Liu, Junshen; Wang, Zhigang; Xu, Qiang; Xu, Hui; Li, Xiaoyan

2014-01-01

Highlights: • The Fe 3 O 4 /PDA hybrid material was synthesized and characterized. • The PDA polymer was firstly applied in environmental remediation. • The Fe 3 O 4 /PDA exhibited high adsorption capacity for multiple pollutants. • Removal efficiencies of pollutants with Fe 3 O 4 /PDA were pH dependent. - Abstract: The polydopamine polymer decorated with magnetic nanoparticles (Fe 3 O 4 /PDA) was synthesized and applied for removal of multiple pollutants. The resulted Fe 3 O 4 /PDA was characterized with elemental analysis, thermo-gravimetric analyses, vibrating sample magnetometer, high resolution transmission electron microscope, Fourier transform infrared spectra, and X-ray photoelectron spectroscopy. The self-polymerization of dopamine could be completed within 8 h, and Fe 3 O 4 nanoparticles were embedded into PDA polymer. Superparamagnetism and large saturation magnetization facilitated collection of sorbents with a magnet. Based on the catechol and amine groups, the PDA polymer provided multiple interactions to combine with pollutants. To investigate the adsorption ability of Fe 3 O 4 /PDA, heavy metal ions and dyes were selected as target pollutants. The adsorption of pollutants was pH dependent due to the variation of surface charges at different solution pH. The removal efficiencies of cation pollutants enhanced with solution pH increasing, and that of anion pollutant was just the opposite. Under the optimal solution pH, the maximum adsorption capacity calculated from Langmuir adsorption isotherm for methylene blue, tartrazine, Cu 2+ , Ag + , and Hg 2+ were 204.1, 100.0, 112.9, 259.1, and 467.3 mg g −1 , respectively. The Fe 3 O 4 /PDA shows great potential for multiple pollutants removal, and this study is the first application of PDA polymer in environmental remediation

A General Strategy for the Preparation of Carbon Nanotubes and Graphene Oxide Decorated with PdO Nanoparticles in Water

Directory of Open Access Journals (Sweden)

Hongkun He

2010-07-01

Full Text Available The preparation of carbon nanotube (CNT/PdO nanoparticles and graphene oxide (GO/PdO nanoparticle hybrids via a general aqueous solution strategy is reported. The PdO nanoparticles are generated in situ on the CNTs and GO by a one-step “green” synthetic approach in aqueous Pd(NO32 solution under ambient conditions without adding any additional chemicals. The production of PdO is confirmed by energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. The morphologies of the resulting CNT/PdO and GO/PdO nanohybrids are characterized by transmission and/or scanning transmission electron microscopy. PdO nanoparticles with an average size of 2–3 nm in diameter are decorated evenly along the surfaces of CNTs and GO. This synthesis strategy is demonstrated to be compatible for 1 CNTs with different modifications, including pristine, oxidized, and polymer-functionalized CNTs; 2 different types of CNTs, including single-walled carbon nanotubes (SWCNTs, double-walled carbon nanotubes (DWCNTs, and multiwalled carbon nanotubes (MWCNTs; and 3 different shapes of carbon materials, including tubular CNTs and planar GO. The as-prepared CNT/PdO and GO/PdO nanohybrids can be transformed into CNT/Pd and GO/Pd nanohybrids by reduction with NaBH4, and can then be used as a heterogeneous catalyst in the catalytic reduction of 4-nitrophenol.

Au Nanoparticles Decorated TiO2 Nanotube Arrays as a Recyclable Sensor for Photoenhanced Electrochemical Detection of Bisphenol A.

Science.gov (United States)

Hu, Liangsheng; Fong, Chi-Chun; Zhang, Xuming; Chan, Leo Lai; Lam, Paul K S; Chu, Paul K; Wong, Kwok-Yin; Yang, Mengsu

2016-04-19

A photorefreshable and photoenhanced electrochemical sensing platform for bisphenol A (BPA) detection based on Au nanoparticles (NPs) decorated carbon doped TiO2 nanotube arrays (TiO2/Au NTAs) is described. The TiO2/Au NTAs were prepared by quick annealing of anodized nanotubes in argon, followed by controllable electrodeposition of Au NPs. The decoration of Au NPs not only improved photoelectrochemical behavior but also enhanced electrocatalytic activities of the resulted hybrid NTAs. Meanwhile, the high photocatalytic activity of the NTAs allowed the electrode to be readily renewed without damaging the microstructures and surface states after a short UV treatment. The electrochemical detection of BPA on TiO2/Au NTAs electrode was significantly improved under UV irradiation as the electrode could provide fresh reaction surface continuously and the further increased photocurrent resulting from the improved separation efficiency of the photogenerated electron-hole pairs derived from the consumption of holes by BPA. The results showed that the refreshable TiO2/Au NTAs electrode is a promising sensor for long-term BPA monitoring with the detection limit (S/N = 3) of 6.2 nM and the sensitivity of 2.8 μA·μM(-1)·cm(-2).

Agar/gelatin bilayer gel matrix fabricated by simple thermo-responsive sol-gel transition method.

Science.gov (United States)

Wang, Yifeng; Dong, Meng; Guo, Mengmeng; Wang, Xia; Zhou, Jing; Lei, Jian; Guo, Chuanhang; Qin, Chaoran

2017-08-01

We present a simple and environmentally-friendly method to generate an agar/gelatin bilayer gel matrix for further biomedical applications. In this method, the thermally responsive sol-gel transitions of agar and gelatin combined with the different transition temperatures are exquisitely employed to fabricate the agar/gelatin bilayer gel matrix and achieve separate loading for various materials (e.g., drugs, fluorescent materials, and nanoparticles). Importantly, the resulting bilayer gel matrix provides two different biopolymer environments (a polysaccharide environment vs a protein environment) with a well-defined border, which allows the loaded materials in different layers to retain their original properties (e.g., magnetism and fluorescence) and reduce mutual interference. In addition, the loaded materials in the bilayer gel matrix exhibit an interesting release behavior under the control of thermal stimuli. Consequently, the resulting agar/gelatin bilayer gel matrix is a promising candidate for biomedical applications in drug delivery, controlled release, fluorescence labeling, and bio-imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Antigen-decorated shell cross-linked nanoparticles: synthesis, characterization, and antibody interactions.

Science.gov (United States)

Joralemon, Maisie J; Smith, Norah L; Holowka, David; Baird, Barbara; Wooley, Karen L

2005-01-01

Antigen-decorated shell cross-linked knedel-like nanoparticles (SCKs) were synthesized and studied as multivalent nanoscale surfaces from which antibody-binding units were presented in a manner that was designed to approach virus particle surfaces. The SCK nanostructures were fabricated with control over the number of antigenic groups, from mixed micellization of amphiphilic diblock copolymer building blocks that contained either an antigen (2,4-dinitrophenyl) or an ethylpropionate group at the hydrophilic alpha-chain terminus. Amphiphilic diblock copolymers were synthesized by atom transfer radical polymerization of tert-butyl acrylate and methyl acrylate sequentially from either a 2,4-dinitrophenyl-functionalized initiator or ethyl 2-bromopropionate, followed by selective removal of the tert-butyl groups to afford 2,4-dinitrophenyl-poly(acrylic acid)60-b-poly(methyl acrylate)60 (DNP-PAA(60)-b-PMA60) and poly(acrylic acid)70-b-poly(methyl acrylate) (PAA70-b-PMA70). Micelles were assembled via addition of water to THF solutions of the polymers in 0:1, 1:1, and 1:0 molar ratios of DNP-PAA60-b-PMA60 to PAA70-b-PMA70, followed by dialysis against water. The acrylic acid groups of the micelle coronas were partially cross-linked (nominally 50%) with 2,2'-(ethylenedioxy)bis(ethylamine), in the presence of 1-(3'-dimethylaminopropyl)-3-ethylcarbodiimide methiodide. Following extensive dialysis against water, the 0%, 50%, and 100% dinitrophenylated shell cross-linked nanoparticles (DNP-SCKs) were characterized with dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), infrared and UV-vis spectroscopies, and analytical ultracentrifugation (AU). The surface accessibility and bioavailability of the DNP units upon the DNP-SCKs were investigated by performing quenching titrations of fluorescein-labeled IgE antibody in solution and degranulation of Ig

Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

International Nuclear Information System (INIS)

Hu, Xiaohong; Chen, Shangneng; Gong, Xiao; Gao, Ziyu; Wang, Xin; Chen, Pin

2017-01-01

As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive β-cyclodextrin (β-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto β-CD. Particularly, the structural details of acetalated β-CD (Ac-β-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-β-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-β-CD1 nanoparticles were prepared by a single oil-in-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-β-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-β-CD nanoparticle could support cell survival and enhance cell viability.

Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Hu, Xiaohong, E-mail: huxiaohong07@163.com; Chen, Shangneng [Jinling Institute of Technology, School of Material Engineering (China); Gong, Xiao [Wuhan University of Technology, State Key Laboratory of Silicate Materials for Architectures (China); Gao, Ziyu; Wang, Xin; Chen, Pin [Jinling Institute of Technology, School of Material Engineering (China)

2017-03-15

As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive β-cyclodextrin (β-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto β-CD. Particularly, the structural details of acetalated β-CD (Ac-β-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-β-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-β-CD1 nanoparticles were prepared by a single oil-in-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-β-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-β-CD nanoparticle could support cell survival and enhance cell viability.

Controlled release from bilayer-decorated magnetoliposomes via electromagnetic heating.

Science.gov (United States)

Chen, Yanjing; Bose, Arijit; Bothun, Geoffrey D

2010-06-22

Nanoscale assemblies that can be activated and controlled through external stimuli represent a next stage in multifunctional therapeutics. We report the formation, characterization, and release properties of bilayer-decorated magnetoliposomes (dMLs) that were prepared by embedding small hydrophobic SPIO nanoparticles at different lipid molecule to nanoparticle ratios within dipalmitoylphosphatidylcholine (DPPC) bilayers. The dML structure was examined by cryogenic transmission electron microscopy and differential scanning calorimetry, and release was examined by carboxyfluorescein leakage. Nanoparticle heating using alternating current electromagnetic fields (EMFs) operating at radio frequencies provided selective release of the encapsulated molecule at low nanoparticle concentrations and under physiologically acceptable EMF conditions. Without radio frequency heating, spontaneous leakage from the dMLs decreased with increasing nanoparticle loading, consistent with greater bilayer stability and a decrease in the effective dML surface area due to aggregation. With radio frequency heating, the initial rate and extent of leakage increased significantly as a function of nanoparticle loading and electromagnetic field strength. The mechanism of release is attributed to a combination of bilayer permeabilization and partial dML rupture.

Direct production of carbon nanofibers decorated with Cu2O by thermal chemical vapor deposition on Ni catalyst electroplated on a copper substrate

Directory of Open Access Journals (Sweden)

MA Vesaghi

2012-12-01

Full Text Available  Carbon nanofibers (CNFs decorated with Cu2O particles were grown on a Ni catalyst layer deposited on a Cu substrate by thermal. chemical vapor deposition from liquid petroleum gas. Ni catalyst nanoparticles with different sizes were produced in an electroplating system at 35˚C. These nanoparticles provide the nucleation sites for CNF growth, removing the need for a buffer layer. High temperature surface segregation of the Cu substrate into the Ni catalyst layer and its exposition to O2 at atmospheric environment, during the CNFs growth, lead to the production of CNFs decorated with Cu2O particles. The surface morphology of the Ni catalyst films and grown CNFs over it was studied by scanning electron microscopy. Transmission electron microscopy and Raman spectroscopy revealed the formation of CNFs. The selected area electron diffraction pattern and electron diffraction studies show that these CNFs were decorated with Cu2O nanoparticles.

Charge-carrier selective electrodes for organic bulk heterojunction solar cell by contact-printed siloxane oligomers

International Nuclear Information System (INIS)

Hwang, Hyun-Sik; Khang, Dahl-Young

2015-01-01

‘Smart’ (or selective) electrode for charge carriers, both electrons and holes, in organic bulk-heterojunction (BHJ) solar cells using insertion layers made of hydrophobically-recovered and contact-printed siloxane oligomers between electrodes and active material has been demonstrated. The siloxane oligomer insertion layer has been formed at a given interface simply by conformally-contacting a cured slab of polydimethylsiloxane stamp for less than 100 s. All the devices, either siloxane oligomer printed at one interface only or printed at both interfaces, showed efficiency enhancement when compared to non-printed ones. The possible mechanism that is responsible for the observed efficiency enhancement has been discussed based on the point of optimum symmetry and photocurrent analysis. Besides its simplicity and large-area applicability, the demonstrated contact-printing technique does not involve any vacuum or wet processing steps and thus can be very useful for the roll-based, continuous production scheme for organic BHJ solar cells. - Highlights: • Carrier-selective insertion layer in organic bulk heterojunction solar cells • Simple contact-printing of siloxane oligomers improves cell efficiency. • Printed siloxane layer reduces carrier recombination at electrode surfaces. • Siloxane insertion layer works equally well at both electrode surfaces. • Patterned PDMS stamp shortens the printing time within 100 s

Electrospun gelatin/poly(ε-caprolactone) fibrous scaffold modified with calcium phosphate for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Rajzer, Izabella, E-mail: irajzer@ath.bielsko.pl [University of Bielsko-Biala (ATH), Department of Mechanical Engineering Fundamentals, Division of Materials Engineering, Willowa 2 Street, 43-309 Bielsko-Biała (Poland); Menaszek, Elżbieta [Jagiellonian University (UJ), Collegium Medicum, Department of Cytobiology, Medyczna 9 Street, 30-068 Cracow (Poland); Kwiatkowski, Ryszard [University of Bielsko-Biala (ATH), Faculty of Materials and Environmental Sciences, Institute of Textile Engineering and Polymer Materials, Willowa 2 Street, 43-309 Bielsko-Biała (Poland); Planell, Josep A.; Castano, Oscar [Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Polytechnic University of Catalonia (UPC), Diagonal 647, 08028 Barcelona (Spain); CIBER-BBN The Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, Barcelona (Spain)

2014-11-01

In this study gelatin (Gel) modified with calcium phosphate nanoparticles (SG5) and polycaprolactone (PCL) were used to prepare a 3D bi-layer scaffold by collecting electrospun PCL and gelatin/SG5 fibers separately in the same collector. The objective of this study was to combine the desired properties of PCL and Gel/SG5 in the same scaffold in order to enhance mineralization, thus improving the ability of the scaffold to bond to the bone tissue. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the wide angle X-ray diffraction (WAXD) measurements confirmed that SG5 nanoparticles were successfully incorporated into the fibrous gelatin matrix. The composite Gel/SG5/PCL scaffold exhibited more enhanced mechanical properties than individual Gel and Gel/SG5 scaffolds. The presence of SG5 nanoparticles accelerated the nucleation and growth of apatite crystals on the surface of the composite Gel/SG5/PCL scaffold in simulated body fluid (SBF). The osteoblast response in vitro to developed electrospun scaffolds (PCL and Gel/SG5/PCL) was investigated by using normal human primary NHOst cell lines. NHOst cell culture studies showed that higher alkaline phosphatase (ALP) activity and better mineralization were obtained in the case of composite materials than in pure PCL scaffolds. The mechanically strong PCL scaffold served as a skeleton, while the Gel/SG5 fibers facilitated cell spreading and mineralization of the scaffold. - Highlights: • Bi-layer scaffolds were produced by electrospinning method. • The addition of nanoparticles enhanced the bioactivity of scaffold. • Bi-layer scaffold enhanced ALP activity and NHOst cell mineralization.

High-temperature hydrogenation of pure and silver-decorated titanate nanotubes to increase their solar absorbance for photocatalytic applications

Energy Technology Data Exchange (ETDEWEB)

Plodinec, Milivoj [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Gajović, Andreja, E-mail: gajovic@irb.hr [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Jakša, Gregor; Žagar, Kristina; Čeh, Miran [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)

2014-04-05

Graphical abstract: The aim of the work is to study how annealing in a reducing atmosphere of titanate nanotubes (TiNT) and Ag decorated titanate nanotubes (TiNT@Ag) influenced on their structure, morphology, phase transitions, UV–ViS-NIR absorbance and photocatalytic activity. An increase of photocatalytic activity after a heat treatment in a reducing atmosphere was observed in the TiNT and TiNT@Ag. We found that the hydrogenated TiNT@Ag samples (TiNT@Ag-HA) had a two-times higher photodegradation impact on the caffeine than the TiNT samples, which is a consequence of the increased absorption of visible light and the synergetic effects between the silver and the TiO{sub 2} nanoparticles that increase the efficiency of the formation of electron–hole pairs and the charge transfer to the surface of the nanoparticles. -- Highlights: • Titanate nanotubes with and without Ag nanoparticles were hydrogenated at 550 °C. • TiO{sub 2} nanostructures obtained by hydrogenation have core–shell structure. • Hydrogenated samples show absorption in the visible spectral region. • Hydrogenated Ag decorated sample show stronger absorption in visible than in UV. • Photocatalytic efficiency is improved by hydrogenation and by Ag nanoparticles. -- Abstract: Titanate nanotubes (TiNTs) and silver-decorated titanate nanotubes (TiNTs@Ag) were synthesized using the hydrothermal method. In the decorated nanotubes the silver particles were obtained by the photoreduction of AgNO{sub 3} under UV light. Pure and Ag-decorated nanotubes were high-temperature heat treated at 550 °C in a hydrogen atmosphere and the “core–shell”-structured TiO{sub 2} nanoparticles were formed. For the structural characterization of all the titanate nanostructures we used conventional and analytical transmission electron microscopy (TEM) techniques, X-ray diffraction (XRD) and Raman spectroscopy. The Ag-decorated titanate nanostructures were additionally studied by X-ray photo

Cancer cell-selective, clathrin-mediated endocytosis of aptamer decorated nanoparticles

Science.gov (United States)

Engelberg, Shira; Modrejewski, Julia; Walter, Johanna G.; Livney, Yoav D.; Assaraf, Yehuda G.

2018-01-01

Lung cancer is the leading cause of cancer mortality worldwide, resulting in 88% deaths of all diagnosed patients. Hence, novel therapeutic modalities are urgently needed. Single-stranded oligonucleotide-based aptamers (APTs) are excellent ligands for tumor cell targeting. However, the molecular mechanisms underlying their internalization into living cells have been poorly studied. Towards the application of APTs for active drug targeting to cancer cells, we herein studied the mechanism underlying S15-APT internalization into human non-small cell lung cancer A549 cells. We thus delineated the mode of entry of a model nanomedical system based on quantum dots (QDs) decorated with S15-APTs as a selective targeting moiety for uptake by A549 cells. These APT-decorated QDs displayed selective binding to, and internalization by target A549 cells, but not by normal human bronchial epithelial BEAS2B, cervical carcinoma (HeLa) and colon adenocarcinoma CaCo-2 cells, hence demonstrating high specificity. Flow cytometric analysis revealed a remarkably low dissociation constant of S15-APTs-decorated QDs to A549 cells (Kd = 13.1 ± 1.6 nM). Through the systematic application of a series of established inhibitors of known mechanisms of endocytosis, we show that the uptake of S15-APTs proceeds via a classical clathrin-dependent receptor-mediated endocytosis. This cancer cell-selective mode of entry could possibly be used in the future to evade plasma membrane-localized multidrug resistance efflux pumps, thereby overcoming an important mechanism of cancer multidrug resistance. PMID:29765515

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

Science.gov (United States)

Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

2013-10-01

Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis of new copper nanoparticle-decorated anchored type ligands: Applications as non-enzymatic electrochemical sensors for hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Ensafi, Ali A., E-mail: Ensafi@cc.iut.ac.ir; Zandi-Atashbar, N.; Ghiaci, M.; Taghizadeh, M.; Rezaei, B.

2015-02-01

In this work, copper nanoparticles (CuNPs) decorated on two new anchored type ligands were utilized to prepare two electrochemical sensors. These ligands are made from bonding amine chains to silica support including SiO{sub 2}–pro–NH{sub 2} (compound I) and SiO{sub 2}–pro–NH–cyanuric–NH{sub 2} (compound II). The morphology of synthesized CuNPs was characterized by transmission electron microscopy (TEM). The nano-particles were in the range of 13–37 nm with the average size of 23 nm. These materials were used to modify carbon paste electrode. Different electrochemical techniques, including cyclic voltammetry, electrochemical impedance spectroscopy and hydrodynamic chronoamperometry, were used to study the sensor behavior. These electrochemical sensors were used as a model for non-enzymatic detection of hydrogen peroxide (H{sub 2}O{sub 2}). To evaluate the abilities of the modified electrodes for H{sub 2}O{sub 2} detection, the electrochemical signals were compared in the absence and presence of H{sub 2}O{sub 2}. From them, two modified electrodes showed significant responses vs. H{sub 2}O{sub 2} addition. The amperograms illustrated that the sensors were selective for H{sub 2}O{sub 2} sensing with linear ranges of 5.14–1250 μmol L{sup −1} and 1.14–1120 μmol L{sup −1} with detection limits of 0.85 and 0.27 μmol L{sup −1} H{sub 2}O{sub 2}, sensitivities of 3545 and 11,293 μA mmol{sup −1} L and with response times less than 5 s for I/CPE and II/CPE, respectively. As further verification of the selected sensor, H{sub 2}O{sub 2} contained in milk sample was analyzed and the obtained results were comparable with the ones from classical control titration method. - Highlights: • Copper nanoparticles decorating on two new anchored type ligands were prepared. • Ligands are bonding to silica support as SiO{sub 2}–pro–NH{sub 2} and SiO{sub 2}–pro–NH–cyanuric–NH{sub 2}. • These materials were used as electrochemical sensors for H

Optical and structural properties of ensembles of colloidal Ag{sub 2}S quantum dots in gelatin

Energy Technology Data Exchange (ETDEWEB)

Ovchinnikov, O. V., E-mail: Ovchinnikov-O-V@rambler.ru; Smirnov, M. S. [Voronezh State University (Russian Federation); Shapiro, B. I. [Moscow State University of Fine Chemical Technologies (Russian Federation); Shatskikh, T. S.; Perepelitsa, A. S.; Korolev, N. V. [Voronezh State University (Russian Federation)

2015-03-15

The size dependences of the absorption and luminescence spectra of ensembles of hydrophilic colloidal Ag{sub 2}S quantum dots produced by the sol-gel method and dispersed in gelatin are analyzed. By X-ray diffraction analysis and transmission electron microscopy, the formation of core/shell nanoparticles is detected. The characteristic feature of the nanoparticles is the formation of crystalline cores, 1.5–2.0 nm in dimensions, and shells of gelatin and its complexes with the components of synthesis. The observed slight size dependence of the position of infrared photoluminescence bands (in the range 1000–1400 nm) in the ensembles of hydrophilic colloidal Ag{sub 2}S quantum dots is explained within the context of the model of the radiative recombination of electrons localized at structural and impurity defects with free holes.

Performance of high amylose starch-composited gelatin films influenced by gelatinization and concentration.

Science.gov (United States)

Wang, Wenhang; Wang, Kun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana; Liu, Anjun

2017-01-01

In order to study the impact of starch in film performance, high amylose corn starch was composited in gelatin films under different gelatinization conditions and, in high and low concentrations (10 and 50wt.%). It was found that hot water gelatinized starch (Gel-Shw) increased film mechanical strength and was dependent upon the starch concentration. The addition of an alkali component to the starch significantly enhanced the swelling of the starch granules and expedited the gelatinization process. Incorporation of starch, especially the alkalized starch (Sha), into the gelatin films decreased film solubility which improved its water resistance and water vapor permeability (WVP). Multiple techniques (DSC, TGA, FT-IR, and XRD) were used to characterize the process and results, including the crosslinking of the dissolved starch molecules and the particles formed from gelatinized starch during retrogradation process, which played an important role in improving the thermal stability of the composited gelatin films. Overall, the starch-gelatin composition provides a potential approach to improve gelatin film performance and benefit its applications in the food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced oxygen reduction activity on surface-decorated perovskite thin films for solid oxide fuel cells

KAUST Repository

Mutoro, Eva; Crumlin, Ethan J.; Biegalski, Michael D.; Christen, Hans M.; Shao-Horn, Yang

2011-01-01

Surface-decoration of perovskites can strongly affect the oxygen reduction activity, and therefore is a new and promising approach to improve SOFC cathode materials. In this study, we demonstrate that a small amount of secondary phase on a (001) La 0.8Sr 0.2CoO 3-δ (LSC) surface can either significantly activate or passivate the electrode. LSC (001) microelectrodes prepared by pulsed laser deposition on a (001)-oriented yttria-stabilized zirconia (YSZ) substrate were decorated with La-, Co-, and Sr-(hydr)oxides/carbonates. "Sr"-decoration with nanoparticle coverage in the range from 50% to 80% of the LSC surface enhanced the surface exchange coefficient, k q, by an order of magnitude while "La"- decoration and "Co"-decoration led to no change and reduction in k q, respectively. Although the physical origin for the enhancement is not fully understood, results from atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy suggest that the observed k q enhancement for "Sr"-decorated surfaces can be attributed largely to catalytically active interface regions between surface Sr-enriched particles and the LSC surface. © 2011 The Royal Society of Chemistry.

A novel enzymatic glucose sensor based on Pt nanoparticles-decorated hollow carbon spheres-modified glassy carbon electrode

International Nuclear Information System (INIS)

Luhana, Charles; Bo Xiangjie; Ju Jian; Guo Liping

2012-01-01

A new glucose biosensor was developed based on hollow carbon spheres decorated with platinum nanoparticles (Pt/HCSs)-modified glassy carbon electrode immobilized with glucose oxidase (GOx) with the help of Nafion. The Pt nanoparticles were well dispersed on the HCSs with an average size of 2.29 nm. The detection of glucose was achieved via electrochemical detection of the enzymatically liberated H 2 O 2 at +0.5 V versus Ag/AgCl at physiologic pH of 7.4. The Pt/HCSs-modified electrode exhibited excellent electrocatalytic activities toward both the oxidation and reduction of H 2 O 2 . The glucose biosensor showed good electrocatalytic performance in terms of high sensitivity (4.1 μA mM −1 ), low detection limit (1.8 μM), fast response time m ) and the maximum current density (i max ) values for the biosensor were 10.94 mM and 887 μA cm −2 respectively. Furthermore, this biosensor showed an acceptable reproducibility and high stability. The interfering signals from ascorbic acid and uric acid at concentration levels normally found in human blood were not much compared with the response to glucose. Blood serum samples were also tested with this biosensor and a good recovery was achieved for the two spiked serum samples.

Silver decorated LaMnO_3 nanorod/graphene composite electrocatalysts as reversible metal-air battery electrodes

International Nuclear Information System (INIS)

Hu, Jie; Liu, Qiunan; Shi, Lina; Shi, Ziwei; Huang, Hao

2017-01-01

Graphical abstract: Silver decorated LaMnO_3 nanorod/reduced graphene oxide composite possess excellent bifunctional electrocatalytic activity and good electrochemical stability in alkaline medium. - Highlights: • Silver decorated LaMnO_3 nanorod/graphene composite were synthesized for the first time. • The ORR and OER of composite in alkaline medium were evaluated. • This composite as an efficient bifunctional catalyst has a good cycle performance. - Abstract: Perovskite LaMnO_3 nanorod/reduced graphene oxides (LMO-NR/RGO) decorated with Ag nanoparticles are studied as a bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. LMO-NR/RGO composites are synthesized by using cetyltrimethyl ammonium bromide (CTAB) as template via a simple hydrothermal reaction followed by heat treatment; overlaying of Ag nanoparticles is obtained through a traditional silver mirror reaction. Electron microscopy reveals that LMO-NR is embedded between the sheets of RGO, and the material is homogeneously overlaid with Ag nanoparticles. The unique composite morphology of Ag/LMO-NR/RGO not only enhances the electron transport property by increasing conductivity but also facilitates the diffusion of electrolytes and oxygen. As confirmed by electrochemical testing, Ag/LMO-NR/RGO exhibits very strong synergy with Ag nanoparticles, LMO-NR, and RGO, and the catalytic activities of Ag/LMO-NR/RGO during ORR and OER are significantly improved. With the novel catalyst, the homemade zinc-air battery can be reversibly charged and discharged and display a stable cycle performance, indicating the great potential of this composite as an efficient bifunctional electrocatalyst for metal-air batteries.

Sensitive and selective electrochemical detection of chromium(VI) based on gold nanoparticle-decorated titania nanotube arrays.

Science.gov (United States)

Jin, Wei; Wu, Guosheng; Chen, Aicheng

2014-01-07

Owing to the severe toxicity and mobility of Cr(VI) in biological and environmental systems, it is of great importance to develop convenient and reliable methods for its detection. Here we report on a facile and effective electrochemical technique for monitoring Cr(VI) concentrations based on the utilization of Au nanoparticle-decorated titania nanotubes (TiO2NTs) grown on a titanium substrate. It was found that the electrochemical reduction of Cr(VI) at the Ti/TiO2NT/Au electrode exhibited an almost 23 fold improvement in activity as compared to a polycrystalline gold electrode, due to its nanoparticle/nanotubular heterojunction infrastructure. As a result, the Ti/TiO2NT/Au electrode demonstrated a wide linear concentration range from 0.10 μM to 105 μM, a low detection limit of 0.03 μM, and a high sensitivity of 6.91 μA μM(-1) Cr(VI) via amperometry, satisfying the detection requirements of the World Health Organization (WHO). Moreover, the Ti/TiO2NT/Au electrode exhibited good resistance against interference from coexisting Cr(III) and other metal ions, and excellent recovery for Cr(VI) detection in both tap and lake water samples. These attributes suggest that this hybrid sensor has strong potential in applications for the selective detection of Cr(VI).

Relaxations of fluorouracil tautomers by decorations of fullerene-like SiCs: DFT studies

Energy Technology Data Exchange (ETDEWEB)

Kouchaki, Alireza [Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Gülseren, Oğuz [Department of Physics, Faculty of Science, Bilkent University, Ankara (Turkey); Hadipour, Nasser [Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mirzaei, Mahmoud, E-mail: mdmirzaei@pharm.mui.ac.ir [Bioinformatics Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of)

2016-06-03

Decorations of silicon carbide (SiC) fullerene-like nanoparticles by fluorouracil (FU) and its tautomers are investigated through density functional theory (DFT) calculations. Two models of fullerene-like particles including Si{sub 12}C{sub 8} and Si{sub 8}C{sub 12} are constructed to be counterparts of decorated hybrid structures, FU@Si{sub 12}C{sub 8} and FU@Si{sub 8}C{sub 12}, respectively. The initial models including original FU and tautomeric structures and SiC nanoparticles are individually optimized and then combined for further optimizations in the hybrid forms. Covalent bonds are observed for FU@Si{sub 12}C{sub 8} hybrids, whereas non-covalent interactions are seen for FU@Si{sub 8}C{sub 12} ones. The obtained properties indicated that Si{sub 12}C{sub 8} model could be considered as a better counterpart for interactions with FU structures than Si{sub 8}C{sub 12} model. The results also showed significant effects of interactions on the properties of atoms close to the interacting regions in nanoparticles. Finally, the tautomeric structures show different behaviors in interactions with SiC nanoparticles, in which the SiC nanoparticles could be employed to detect the situations of tautomeric processes for FU structures. - Highlights: • Possibilities of interaction between fluorouracil and silicon carbides have been recognized. • Possibilities for covalent and non-covalent interactions have been indicated. • Detections of tautomeric structures have been investigated.

Direct electrochemistry of glucose oxidase and a biosensor for glucose based on a glass carbon electrode modified with MoS2 nanosheets decorated with gold nanoparticles

International Nuclear Information System (INIS)

Su, Shao; Sun, Haofan; Xu, Fei; Yuwen, Lihui; Wang, Lianhui; Fan, Chunhai

2014-01-01

An electrochemical glucose biosensor was developed by immobilizing glucose oxidase (GOx) on a glass carbon electrode that was modified with molybdenum disulfide (MoS 2 ) nanosheets that were decorated with gold nanoparticles (AuNPs). The electrochemical performance of the modified electrode was investigated by cyclic voltammetry, and it is found that use of the AuNPs-decorated MoS 2 nanocomposite accelerates the electron transfer from electrode to the immobilized enzyme. This enables the direct electrochemistry of GOx without any electron mediator. The synergistic effect the MoS 2 nanosheets and the AuNPs result in excellent electrocatalytic activity. Glucose can be detected in the concentration range from 10 to 300 μM, and down to levels as low as 2.8 μM. The biosensor also displays good reproducibility and long-term stability, suggesting that it represents a promising tool for biological assays. (author)

Poloxamer-Decorated Polymer Nanoparticles for Lung Surfactant Compatibility

DEFF Research Database (Denmark)

Beck-Broichsitter, Moritz; Bohr, Adam; Ruge, Christian A

2017-01-01

Lung-delivered polymer nanoparticles provoked dysfunction of the essential lung surfactant system. A steric shielding of the nanoparticle surface with poloxamers could minimize the unwanted interference of polymer nanoparticles with the biophysical function of lung surfactant. The extent of poly......(styrene) and poly(lactide) nanoparticle-induced lung surfactant inhibition could be related to the type and content of the applied poloxamer. Escalations of the adsorbed coating layer thickness (>3 nm) as well as concentration (brush- rather than mushroom-like conformation of poly(ethylene glycol), chain......-associated proteins. Poloxamer-modified polymer nanoparticles represent a promising nanomedicine platform intended for respiratory delivery revealing negligible effects on the biophysical functionality of the lining layer present in the deep lungs....

TiO2 nanosheets decorated with B4C nanoparticles as photocatalysts for solar fuel production under visible light irradiation

Science.gov (United States)

Zhang, Xiaojie; Yang, Jipeng; Cai, Tiancong; Zuo, Guoqiang; Tang, Changqing

2018-06-01

Boron carbide (B4C) nanoparticles-decorated anatase titanium dioxide (TiO2) nanosheets photocatalysts were synthesized by a hydrothermal method in the presence of hydrofluoric acid and characterized by field emission scanning electron microscope, high-resolution transmission electron microscope, UV-vis diffuse reflectance spectra, photoluminescence spectra, etc. With metallic Pt nanoparticles as a co-catalyst, the as-synthesized B4C/TiO2 composites were evaluated using photocatalytic CO2 or H2O reduction to solar fuels such as methane and hydrogen. Under either simulated sunlight or visible light irradiation, coupling p-type B4C with n-type anatase TiO2 significantly improved the photocatalytic performance. Both photoluminescence and transient photocurrent measurements indicated that the interfacial coupling effect between B4C and anatase TiO2 could significantly promote photo-excited charges separations. On the basis of measurements and literatures, a possible mechanism of excited charges transfer at the B4C-anatase TiO2 heterojunction interface during irradiation was deduced.

TEM and SP-ICP-MS analysis of the release of silver nanoparticles from decoration of pastry.

Science.gov (United States)

Verleysen, E; Van Doren, E; Waegeneers, N; De Temmerman, P-J; Abi Daoud Francisco, M; Mast, J

2015-04-08

Metallic silver is an EU approved food additive referred to as E174. It is generally assumed that silver is only present in bulk form in the food chain. This work demonstrates that a simple treatment with water of "silver pearls", meant for decoration of pastry, results in the release of a subfraction of silver nanoparticles. The number-based size and shape distributions of the single, aggregated, and/or agglomerated particles released from the silver pearls were determined by combining conventional bright-field TEM imaging with semiautomatic particle detection and analysis. In addition, the crystal structure of the particles was studied by electron diffraction and chemical information was obtained by combining HAADF-STEM imaging with EDX spectroscopy and mapping. The TEM results were confirmed by SP-ICP-MS. The representative Ag test nanomaterial NM-300 K was used as a positive control to determine the uncertainty on the measurement of the size and shape of the particles.

Zinc oxide nanotubes decorated with silver nanoparticles as an ultrasensitive substrate for surface-enhanced Raman scattering

International Nuclear Information System (INIS)

Gao, M.; Feng, B.; Sun, Y.; Xing, G.; Li, S.; Yang, J.; Yang, L.; Zhang, Y.; Liu, H.; Fan, H.; Sui, Y.; Zhang, Z.; Liu, S.; Song, H.

2012-01-01

We report on the fabrication of a highly aligned silver-decorated array of zinc oxide nanotubes for use in surface-enhanced Raman spectroscopy (SERS). The ZnO nanotube array was first prepared by chemical etching, and the silver nanoparticles (AgNPs) were then deposited on their surface by magnetron sputtering. Such ZnO/Ag hybrid structures are shown to act as SERS-active substrates with remarkable sensitivity. The enhancement factor can be as high as 10 5 when using 4-mercaptopyridine in solution as a SERS probe. The synergistic combination between SERS 'hot spots' and the formation of an interfacial electric field between the zinc oxide nanotubes and the AgNPs in our opinion contribute to the high sensitivity. The relative standard deviations of signal intensities for the major SERS peaks are <7 %. This demonstrates that the optimized ZnO/Ag hybrid represents an excellent SERS substrate that may be used in trace analysis and ultrasensitive molecular sensing. (author)

Synthesis and characterization of silver nanoparticles: effect on phytopathogen Colletotrichum gloesporioides

Science.gov (United States)

Aguilar-Méndez, Miguel A.; San Martín-Martínez, Eduardo; Ortega-Arroyo, Lesli; Cobián-Portillo, Georgina; Sánchez-Espíndola, Esther

2011-06-01

Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin as capping agent. The obtained nanoparticles were characterized by means of UV-Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV-Vis spectra indicated the formation of silver nanoparticles preferably spherical and of relatively small size (silver nanoparticles. By means of FTIR spectroscopy it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration. The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner.

Sensing of low concentration of ammonia at room temperature by decorated multi-walled carbon nanotube: fabrication and characteristics

Science.gov (United States)

Hasnahena, S. T.; Roy, M.

2018-01-01

A chemical sensor based on multi-walled carbon nanotube (MWCNT) decorated with densely populated thiol-capped gold nanoparticles (AuNPs) with sizes smaller than 3 nm for sensing low concentrations of ammonia gas is reported. The functionalized MWCNTs, subsequently decorated with AuNPs following an easy fabrication route were exposed to NH3 gas at the room temperature and the electrical resistance of the sensor changed upon exposure. The sensor also partially recovered the initial state after sensing in the normal air environment (without any dry air or N2 gas purge). The gold nanoparticles decoration is found to enhance the sensitivity and selectivity of MWCNT towards NH3 gas under ambient conditions with a reduced response and recovery time. The material was structurally characterized by Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. Thermal stability of the sensor till 574 °C was demonstrated by TGA analysis. This papers describes how thiol-capped AuNPs are uniformly decorated on the outer walls of the MWCNTs with a separation of 2-3 nm making use of the ionic nature of Au and how this uniform distribution of AuNPs increases the active sites for absorption of NH3 gas molecules leading to sensing its low concentrations.

Anti-microbial surfaces: An approach for deposition of ZnO nanoparticles on PVA-Gelatin composite film by screen printing technique

Energy Technology Data Exchange (ETDEWEB)

Meshram, J.V.; Koli, V.B.; Phadatare, M.R.; Pawar, S.H., E-mail: shpawar1946@gmail.com

2017-04-01

Initially micro-organisms get exposed to the surfaces, this demands development of anti-microbial surfaces to inhibit their proliferation. Therefore, herein, we attempt screen printing technique for development of PVA-GE/ZnO nanocomposite (PG/ZnO) films. The synthesis of PG/ZnO nanocomposite includes two steps as: (i) Coating of Zinc Oxide nanoparticles (ZnO NPs) by poly ethylene glycol in order to be compatible with organic counterparts. (ii) Deposition of coated nanoparticles on the PG film surface. The results suggest the enhancement in anti-microbial activity of PG/ZnO nanocomposite over pure ZnO NPs against both Gram positive Bacillus subtilis and Gram negative Escherichia coli from zone of inhibition. The uniformity in deposition is further confirmed by scanning electron microscopy (SEM) images. The phase identification of ZnO NPs and formation of PG/ZnO nanocomposite has been confirmed by X-ray diffraction (XRD) analysis and UV–vis spectroscopy (UV–vis). The Attenuated total reflection Spectroscopy (ATR) analysis indicates the ester bond between PVA and gelatin molecules. The thermal stability of nanocomposite is studied by thermogravimetric analysis (TGA) revealing increase in crystallinity due to ZnO NPs which could be utilized to inhibit the growth of micro-organisms. The tensile strength is found to be higher and percent elongation is double of PG/ZnO nanocomposite than PG composite film. - Highlights: • Synthesis of PG/ZnO nanocomposite by screen printing technique • Antimicrobial activity is due presence of ZnO nanoparticles on PG composite. • Improved tensile strength due to ZnO nanoparticles.

Siloxane removal and sludge disintegration using thermo-alkaline treatments with air stripping prior to anaerobic sludge digestion

International Nuclear Information System (INIS)

Oshita, Kazuyuki; Fujime, Motochika; Takaoka, Masaki; Fujimori, Takashi; Appels, Lise; Dewil, Raf

2015-01-01

Highlights: • Siloxanes hamper the energy-use of anaerobic digestion biogas. • D5 siloxane was considered as target compound in this study. • The treatment removed 80% of D5 in sewage sludge at 55 °C and 135 g-NaOH kg −1 -VTS. • D5 removal and the disintegration of VSS in the sludge were correlated. • At the optimal conditions, the costs of anaerobic digestion were notably diminished. - Abstract: A thermo-alkaline treatment with air stripping was applied before anaerobic sludge digestion for both siloxane removal and sludge disintegration. The treatment was expected to increase the amount of biogas produced and to reduce the amount of siloxane in the gas. Adding sodium hydroxide (NaOH) to the sludge improved the removal of siloxane from the sludge, with approximately 90% of the siloxane removed to the gas phase using a thermo-alkaline treatment. Over 80% of decamethylcyclopentasiloxane (D5) could be removed under the following conditions: 55 °C treatment temperature, 135 g-NaOH kg −1 volatile total solids (VTS), and 0.5 L min −1 air-stripping rate. The disintegration ratio of volatile suspended solids (VSS) in the sludge was correlated with the D5 removal ratio. Because most of the siloxane was adsorbed to, or was contained in the VSS, the siloxane removal ratio increased with VSS disintegration. Finally, the energy consumption and operational costs of this system were evaluated for several scenarios. Thermo-alkaline treatment at the indicated operational conditions had the lowest operating costs for a 400 m 3 day −1 anaerobic sludge digestion system

Thermal characterisation of gelatin extracted from yellowfin tuna skin and commercial mammalian gelatin.

Science.gov (United States)

Rahman, Mohammad Shafiur; Al-Saidi, Ghalib Said; Guizani, Nejib

2008-05-15

Glass transition and other thermal characteristics of gelatin from different sources were studied by differential scanning calorimetry (DSC) and modulated DSC (MDSC). The initial glass transition temperatures of equilibrated gelatin samples at 11.3% relative humidity, determined from reversible heat flow thermogram of MDSC, were 23, 75 and 59°C, respectively, for tuna skin, bovine and porcine gelatin. When gelatin samples were equilibrated at higher relative humidity of 52.9%, glass transition temperature of fish skin and bovine gelatin decreased to -3 and 57°C, respectively. Further increase of equilibration relative humidity to 75.3% showed increased value in the case of tuna skin, whereas bovine and porcine did not show any significant change. DSC and MDSC results indicated that tuna gelatin showed lower glass transition compared to mammalian source gelatin equilibrated at the same constant relative humidity. In general glass transition measured by DSC was found lower than the values measured by MDSC. The results in this study showed that the degree of plasticization varied with the source of gelatin as well as their extraction methods. Copyright © 2007 Elsevier Ltd. All rights reserved.

Hexagonal boron nitride nanoparticles decorated halloysite clay nanotubes as a potential hydrogen storage medium

Energy Technology Data Exchange (ETDEWEB)

Muthu, R. Naresh, E-mail: rnaresh7708@gmail.com; Rajashabala, S. [School of Physics, Madurai Kamaraj University, Madurai-625021, Tamil Nadu (India); Kannan, R. [Department of Physics, University College of Engineering, Anna University, Dindigul-624622 (India); Department of Materials Science and Engineering, Cornell University, Ithaca 14850, New York (United States)

2016-05-23

The light weight and compact hydrogen storage materials is still prerequisite for the carbon free hydrogen fuel cell technology. In this work, the hydrogen storage performance of acid treated halloysite clay nanotubes (A-HNTs) and hexagonal boron nitride (h-BN) nanoparticles decorated acid treated halloysite nanoclay composite (A-HNT-h-BN) are demonstrated, where facile ultrasonic technique is adopted for the synthesis of A-HNT-h-BN nanoclay composite. Hydrogen storage studies were carried out using Sieverts-like hydrogenation setup. The A-HNTs and A-HNT-h-BN nanoclay composite were analyzed by XRD, FTIR, HRTEM, EDX, CHNS-elemental analysis and TGA. The A-HNT-h-BN nanoclay composite shows superior storage capacity of 2.19 wt% at 50 °C compared to the A-HNTs (0.58 wt%). A 100% desorption of stored hydrogen is noted in the temperature range of 138–175 °C. The average binding energy of hydrogen was found to be 0.34 eV for the prepared A-HNT-h-BN nanoclay composite. The excellent storage capability of A-HNT-h-BN nanoclay composite towards hydrogen at ambient temperature may find bright perspective in hydrogen fuel cell technology in near future.

Hexagonal boron nitride nanoparticles decorated halloysite clay nanotubes as a potential hydrogen storage medium

International Nuclear Information System (INIS)

Muthu, R. Naresh; Rajashabala, S.; Kannan, R.

2016-01-01

The light weight and compact hydrogen storage materials is still prerequisite for the carbon free hydrogen fuel cell technology. In this work, the hydrogen storage performance of acid treated halloysite clay nanotubes (A-HNTs) and hexagonal boron nitride (h-BN) nanoparticles decorated acid treated halloysite nanoclay composite (A-HNT-h-BN) are demonstrated, where facile ultrasonic technique is adopted for the synthesis of A-HNT-h-BN nanoclay composite. Hydrogen storage studies were carried out using Sieverts-like hydrogenation setup. The A-HNTs and A-HNT-h-BN nanoclay composite were analyzed by XRD, FTIR, HRTEM, EDX, CHNS-elemental analysis and TGA. The A-HNT-h-BN nanoclay composite shows superior storage capacity of 2.19 wt% at 50 °C compared to the A-HNTs (0.58 wt%). A 100% desorption of stored hydrogen is noted in the temperature range of 138–175 °C. The average binding energy of hydrogen was found to be 0.34 eV for the prepared A-HNT-h-BN nanoclay composite. The excellent storage capability of A-HNT-h-BN nanoclay composite towards hydrogen at ambient temperature may find bright perspective in hydrogen fuel cell technology in near future.

Hexagonal boron nitride nanoparticles decorated halloysite clay nanotubes as a potential hydrogen storage medium

Science.gov (United States)

Muthu, R. Naresh; Rajashabala, S.; Kannan, R.

2016-05-01

The light weight and compact hydrogen storage materials is still prerequisite for the carbon free hydrogen fuel cell technology. In this work, the hydrogen storage performance of acid treated halloysite clay nanotubes (A-HNTs) and hexagonal boron nitride (h-BN) nanoparticles decorated acid treated halloysite nanoclay composite (A-HNT-h-BN) are demonstrated, where facile ultrasonic technique is adopted for the synthesis of A-HNT-h-BN nanoclay composite. Hydrogen storage studies were carried out using Sieverts-like hydrogenation setup. The A-HNTs and A-HNT-h-BN nanoclay composite were analyzed by XRD, FTIR, HRTEM, EDX, CHNS-elemental analysis and TGA. The A-HNT-h-BN nanoclay composite shows superior storage capacity of 2.19 wt% at 50 °C compared to the A-HNTs (0.58 wt%). A 100% desorption of stored hydrogen is noted in the temperature range of 138-175 °C. The average binding energy of hydrogen was found to be 0.34 eV for the prepared A-HNT-h-BN nanoclay composite. The excellent storage capability of A-HNT-h-BN nanoclay composite towards hydrogen at ambient temperature may find bright perspective in hydrogen fuel cell technology in near future.

Ru-decorated Pt surfaces as model fuel cell electrocatalysts for CO electrooxidation.

Science.gov (United States)

Maillard, F; Lu, G-Q; Wieckowski, A; Stimming, U

2005-09-01

This feature article concerns Pt surfaces modified (decorated) by ruthenium as model fuel cell electrocatalysts for electrooxidation processes. This work reveals the role of ruthenium promoters in enhancing electrocatalytic activity toward organic fuels for fuel cells, and it particularly concerns the methanol decomposition product, surface CO. A special focus is on surface mobility of the CO as it is catalytically oxidized to CO(2). Different methods used to prepare Ru-decorated Pt single crystal surfaces as well as Ru-decorated Pt nanoparticles are reviewed, and the methods of characterization and testing of their activity are discussed. The focus is on the origin of peak splitting involved in the voltammetric electrooxidation of CO on Ru-decorated Pt surfaces, and on the interpretative consequences of the splitting for single crystal and nanoparticle Pt/Ru bimetallic surfaces. Apparently, screening through the literature allows formulating several models of the CO stripping reaction, and the validity of these models is discussed. Major efforts are made in this article to compare the results reported by the Urbana-Champaign group and the Munich group, but also by other groups. As electrocatalysis is progressively more and more driven by theory, our review of the experimental findings may serve to summarize the state of the art and clarify the roads ahead. Future studies will deal with highly dispersed and reactive nanoscale surfaces and other more advanced catalytic materials for fuel cell catalysis and related energy applications. It is expected that the metal/metal and metal/substrate interactions will be increasingly investigated on atomic and electronic levels, with likewise increasing participation of theory, and the structure and reactivity of various monolayer catalytic systems involving more than two metals (that is ternary and quaternary systems) will be interrogated.

Motion-Based pH Sensing Based on the Cartridge-Case-like Micromotor.

Science.gov (United States)

Su, Yajun; Ge, Ya; Liu, Limei; Zhang, Lina; Liu, Mei; Sun, Yunyu; Zhang, Hui; Dong, Bin

2016-02-17

In this paper, we report a novel cartridge-case-like micromotor. The micromotor, which is fabricated by the template synthesis method, consists of a gelatin shell with platinum nanoparticles decorating its inner surface. Intriguingly, the resulting cartridge-case-like structure exhibits a pH-dependent "open and close" feature, which originates from the pH responsiveness of the gelatin material. On the basis of the catalytic activity of the platinum nanoparticle inside the gelatin shell, the resulting cartridge-case-like structure is capable of moving autonomously in the aqueous solution containing the hydrogen peroxide fuel. More interestingly, we find out that the micromotor can be utilized as a motion-based pH sensor over the whole pH range. The moving velocity of the micromotor increases monotonically with the increase of pH of the analyte solution. Three different factors are considered to be responsible for the proportional relation between the motion speed and pH of the analyte solution: the peroxidase-like and oxidase-like catalytic behavior of the platinum nanoparticle at low and high pH, the volumetric decomposition of the hydrogen peroxide under the basic condition and the pH-dependent catalytic activity of the platinum nanoparticle caused by the swelling/deswelling behavior of the gelatin material. The current work highlights the impact of the material properties on the motion behavior of a micromotor, thus paving the way toward its application in the motion-based sensing field.

Siloxane D4 capture by hydrophobic microporous materials

OpenAIRE

Mito-oka, Yasuko; Horike, Satoshi; Nishitani, Yusuke; Masumori, Tadao; Inukai, Munehiro; Hijikata, Yuh; Kitagawa, Susumu

2013-01-01

Porous substances, including crystalline coordination materials and an amorphous organic polymer, were studied for their selective adsorption of siloxane D4. The investigated materials demonstrated a level of uptake comparable to that of conventional activated carbon.

Graphene oxide decorated with silver nanoparticles as a coating on a stainless-steel fiber for solid-phase microextraction.

Science.gov (United States)

Wang, Licheng; Hou, Xiudan; Li, Jubai; Liu, Shujuan; Guo, Yong

2015-07-01

A novel graphene oxide decorated with silver nanoparticles coating on a stainless-steel fiber for solid-phase microextraction was prepared. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the coating surface and showed that silver nanoparticles were dispersed on the wrinkled graphene oxide surface. Coupled to gas chromatography with flame ionization detection, the extraction abilities of the fiber for polycyclic aromatic hydrocarbons were examined in the headspace solid-phase microextraction mode. The extraction parameters including adsorption time, adsorption temperature, salt concentration, desorption time and desorption temperature were investigated. Under the optimized condition, wide linearity with low limits of detection from 2 to 10 ng/L was obtained. The relative standard deviations for single-fiber repeatability and fiber-to-fiber reproducibility were less than 10.6 and 17.5%, respectively. The enrichment factors were from 1712.5 to 4503.7, showing the fiber has good extraction abilities. Moreover, the fiber exhibited a good stability and could be reused for more than 120 times. The established method was also applied for determination of polycyclic aromatic hydrocarbons in two real water samples and the recoveries of analytes ranged from 84.4-116.3% with relative standard deviations less than 16.2%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly efficient visible light photocatalytic reduction of CO2 to hydrocarbon fuels by Cu-nanoparticle decorated graphene oxide.

Science.gov (United States)

Shown, Indrajit; Hsu, Hsin-Cheng; Chang, Yu-Chung; Lin, Chang-Hui; Roy, Pradip Kumar; Ganguly, Abhijit; Wang, Chen-Hao; Chang, Jan-Kai; Wu, Chih-I; Chen, Li-Chyong; Chen, Kuei-Hsien

2014-11-12

The production of renewable solar fuel through CO2 photoreduction, namely artificial photosynthesis, has gained tremendous attention in recent times due to the limited availability of fossil-fuel resources and global climate change caused by rising anthropogenic CO2 in the atmosphere. In this study, graphene oxide (GO) decorated with copper nanoparticles (Cu-NPs), hereafter referred to as Cu/GO, has been used to enhance photocatalytic CO2 reduction under visible-light. A rapid one-pot microwave process was used to prepare the Cu/GO hybrids with various Cu contents. The attributes of metallic copper nanoparticles (∼4-5 nm in size) in the GO hybrid are shown to significantly enhance the photocatalytic activity of GO, primarily through the suppression of electron-hole pair recombination, further reduction of GO's bandgap, and modification of its work function. X-ray photoemission spectroscopy studies indicate a charge transfer from GO to Cu. A strong interaction is observed between the metal content of the Cu/GO hybrids and the rates of formation and selectivity of the products. A factor of greater than 60 times enhancement in CO2 to fuel catalytic efficiency has been demonstrated using Cu/GO-2 (10 wt % Cu) compared with that using pristine GO.

Aqueously Dispersed Silver Nanoparticle-Decorated Boron Nitride Nanosheets for Reusable, Thermal Oxidation-Resistant Surface Enhanced Raman Spectroscopy (SERS) Devices

Science.gov (United States)

Lin, Yi; Bunker, Christopher E.; Fernandos, K. A. Shiral; Connell, John W.

2012-01-01

The impurity-free aqueous dispersions of boron nitride nanosheets (BNNS) allowed the facile preparation of silver (Ag) nanoparticle-decorated BNNS by chemical reduction of an Ag salt with hydrazine in the presence of BNNS. The resultant Ag-BNNS nanohybrids remained dispersed in water, allowing convenient subsequent solution processing. By using substrate transfer techniques, Ag-BNNS nanohybrid thin film coatings on quartz substrates were prepared and evaluated as reusable surface enhanced Raman spectroscopy (SERS) sensors that were robust against repeated solvent washing. In addition, because of the unique thermal oxidation-resistant properties of the BNNS, the sensor devices may be readily recycled by short-duration high temperature air oxidation to remove residual analyte molecules in repeated runs. The limiting factor associated with the thermal oxidation recycling process was the Ostwald ripening effect of Ag nanostructures.

Nanomodification of the electrodes in microbial fuel cell: impact of nanoparticle density on electricity production and microbial community

DEFF Research Database (Denmark)

Al Atraktchi, Fatima Al-Zahraa; Zhang, Yifeng; Angelidaki, Irini

2014-01-01

The nano-decoration of electrode with nanoparticles is one effective way to enhance power output of microbial fuel cells (MFCs). However, the amount of nanoparticles used for decoration has not been optimized yet, and how it affects the microbial community is still unknown. In this study, differe...

Porous TiO_2 nanofibers decorated CdS nanoparticles by SILAR method for enhanced visible-light-driven photocatalytic activity

International Nuclear Information System (INIS)

Tian, Fengyu; Hou, Dongfang; Hu, Fuchao; Xie, Kui; Qiao, Xiuqing; Li, Dongsheng

2017-01-01

Graphical abstract: A heterojunction photocatalyst with CdS Nanoparticles self-assembled via SILAR Method at surfaces of electrospun TiO2 nanofibers shows enhanced visible-light photocatalytic activities. - Highlights: • Combined electrospinning and successive ionic layer adsorption and reaction process. • Pouous TiO_2 nanofibers decorated CdS nanoparticles. • Synergetic effect of photosensitization and heterojunction. - Abstract: 1D porous CdS nanoparticles/TiO_2 nanofibers heterostructure has been fabricated via simple electrospinning and a successive ionic layer adsorption and reaction (SILAR) process. The morphology, composition, and optical properties of the resulting CdS/TiO_2 heterostructures can be rationally tailored through changing the SILAR cycles. The photocatalytic hydrogen evolution and decomposition of rhodamine B (RhB) of the as-synthesized heterostructured photocatalysts were investigated under visible light irradiation. Compared to TiO_2 nanofibers，the as-obtained CdS/TiO_2 heterostructures exhibit enhanced photocatalytic activity for hydrogen production and decomposition of RhB under visible-light irradiation. The heterojunction system performs best with H_2 generation rates of 678.61 μmol h"−"1 g"−"1 under visible light irradiation which benefits from the two effects: (a) the 1D porous nanofibrous morphology contributes to not only more active sites but also more efficient transfer of the photogenerated charges (b) the synergetic effect of heterojunction and photosensitization reducing the recombination of photogenerated electrons and holes.

Extraction and physicochemical characterization of broiler (Gallus gallus domesticus) skin gelatin compared to commercial bovine gelatin.

Science.gov (United States)

Aykin-Dinçer, E; Koç, A; Erbas, M

2017-09-01

Gelatin was extracted from broiler (Gallus gallus domesticus) skins and analyzed to compare its physicochemical properties with those of commercial bovine gelatin. The average yield of broiler skin gelatin was 6.5% on a wet weight basis. Broiler skin gelatin had more α1-and α2-chains than β-chain and contained high molecular weight (γ-chain) polymers. Glycine was the dominant amino acid in broiler skin gelatin (20.26%), followed by proline (Pro) (15.12%) then hydroxyproline (Hyp) (11.36%). Compared to commercial bovine gelatin, broiler skin gelatin had less total imino acids (Pro and Hyp) but a higher (33.65 vs. 31.38°C) melting temperature (P commercial bovine gelatins appeared to be associated with differences in their amino acid composition and molecular weight distribution. The sensory evaluation results revealed that broiler skin gelatin could be a potential alternative to commercial bovine gelatin, useful in various food products. © 2017 Poultry Science Association Inc.

High-rate capability silicon decorated vertically aligned carbon nanotubes for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Gohier, Aurelien; Kim, Ki-Hwan; Maurice, Jean-Luc; Cojocaru, Costel Sorin [Laboratoire de Physique des Interfaces et des Couches Minces, LPICM, Ecole Polytechnique, route de Saclay, 91128 Palaiseau Cedex (France); Laik, Barbara; Pereira-Ramos, Jean-Pierre [Institut de Chimie et des Materiaux Paris-Est, ICMPE/GESMAT, UMR 7182 CNRS-UPEC, 2 rue Henri Dunant, 94320 Thiais (France); Van, Pierre Tran [Renault SAS, DREAM/DETA/SEE, 1, avenue du Golf, 78288 Guyancourt (France)

2012-05-15

The concept of a hybrid nanostructured collector made of thin vertically aligned carbon nanotubes (CNTs) decorated with Si nanoparticles provides high power density anodes in lithium-ion batteries. An impressive rate capability is achieved due to the efficient electronic conduction of CNTs combined with well defined electroactive Si nanoparticles: capacities of 3000 mAh g{sup -1} at 1.3C and 800 mAh g{sup -1} at 15C are achieved. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Reproducible preparation of a stable polypyrrole-coated-silver nanoparticles decorated polypyrrole-coated-polycaprolactone-nanofiber-based cloth electrode for electrochemical sensor application

Science.gov (United States)

Li, Li; Wang, Xiaoping; Liu, Guiting; Wang, Zhenzhen; Wang, Feng; Guo, Xiaoyu; Wen, Ying; Yang, Haifeng

2015-11-01

A piece of conductive cloth has been successfully constructed from polypyrrole-coated silver nanoparticle (Ag@PPy) composites decorated on electrospun polycaprolactone (PCL) nanofibers that formed the core-shell structure of Ag@PPy/PCL@PPy via a photo-induced one-step redox reaction. The photochemical reaction method both accelerated the rate of formation of silver nanoparticles (Ag NPs) and enhanced the dispersion of Ag NPs at the surface of PCL@PPy film. The resulting Ag@PPy/PCL@PPy-based cloth was flexible enough to be cut and pasted onto a glass carbon electrode for the preparation of a biosensor. The resulting biosensor showed good electrochemical activity toward the reduction of H2O2 with low detection limit down to 1 μM (S/N = 3) and wide linear detection ranging from 0.01 mM to 3.5 mM (R2 = 0.990). This sensor has been applied to detect the trace H2O2 residual in milk. The cloth electrode has been proved to exhibit long-term stability, high selectivity, and excellent reproducibility.

Reproducible preparation of a stable polypyrrole-coated-silver nanoparticles decorated polypyrrole-coated-polycaprolactone-nanofiber-based cloth electrode for electrochemical sensor application

International Nuclear Information System (INIS)

Li, Li; Wang, Xiaoping; Liu, Guiting; Wang, Zhenzhen; Wang, Feng; Guo, Xiaoyu; Wen, Ying; Yang, Haifeng

2015-01-01

A piece of conductive cloth has been successfully constructed from polypyrrole-coated silver nanoparticle (Ag@PPy) composites decorated on electrospun polycaprolactone (PCL) nanofibers that formed the core–shell structure of Ag@PPy/PCL@PPy via a photo-induced one-step redox reaction. The photochemical reaction method both accelerated the rate of formation of silver nanoparticles (Ag NPs) and enhanced the dispersion of Ag NPs at the surface of PCL@PPy film. The resulting Ag@PPy/PCL@PPy-based cloth was flexible enough to be cut and pasted onto a glass carbon electrode for the preparation of a biosensor. The resulting biosensor showed good electrochemical activity toward the reduction of H 2 O 2 with low detection limit down to 1 μM (S/N = 3) and wide linear detection ranging from 0.01 mM to 3.5 mM (R 2  = 0.990). This sensor has been applied to detect the trace H 2 O 2 residual in milk. The cloth electrode has been proved to exhibit long-term stability, high selectivity, and excellent reproducibility. (paper)

Iridium-decorated palladium-platinum core-shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell.

Science.gov (United States)

Wang, Chen-Hao; Hsu, Hsin-Cheng; Wang, Kai-Ching

2014-08-01

Carbon-supported Pt, Pd, Pd-Pt core-shell (Pt(shell)-Pd(core)/C) and Ir-decorated Pd-Pt core-shell (Ir-decorated Pt(shell)-Pd(core)/C) catalysts were synthesized, and their physical properties, electrochemical behaviors, oxygen reduction reaction (ORR) characteristics and proton exchange membrane fuel cell (PEMFC) performances were investigated herein. From the XRD patterns and TEM images, Ir-decorated Pt(shell)-Pd(core)/C has been confirmed that Pt was deposited on the Pd nanoparticle which had the core-shell structure. Ir-decorated Pt(shell)-Pd(core)/C has more positive OH reduction peak than Pt/C, which is beneficial to weaken the binding energy of Pt-OH during the ORR. Thus, Ir-decorated Pt(shell)-Pd(core)/C has higher ORR activity than Pt/C. The maximum power density of H2-O2 PEMFC using Ir-decorated Pt(shell)-Pd(core)/C is 792.2 mW cm(-2) at 70°C, which is 24% higher than that using Pt/C. The single-cell accelerated degradation test of PEMFC using Ir-decorated Pt(shell)-Pd(core)/C shows good durability by the potential cycling of 40,000 cycles. This study concludes that Ir-decorated Pt(shell)-Pd(core)/C has the low Pt content, but it can facilitate the low-cost and high-efficient PEMFC. Copyright © 2013 Elsevier Inc. All rights reserved.

[Substantiation of medical-engineering specifications for polymethyl siloxane removal by life support systems].

Science.gov (United States)

Pakhomova, A A; Aksel'-Rubinshteĭn, V Z; Mikos, K N; Nikitin, E I

2009-01-01

Analysis of experimental data about the quantitative and qualitative chemical make-up of air in the orbital station Mir and International space station (ISS) showed a permanent presence of silicon. The main source of silicon contaminants seems to be a variety of polymethyl siloxane liquids and siloxane coating of electronics. The article describes the volatile silicon contaminants detected in space stations air. To control concentrations of silicon, the existing air purification system needs to be augmented with carbons having the micropore entrance larger than diameters of silicon-containing molecules. It is also important to elaborate the technology of polymethyl siloxane liquids synthesis so as to reduce the amount of volatile admixtures emission and to observe rigorously the pre-flight off-gassing requirements with special concern about silicon coatings.

Silver decorated LaMnO{sub 3} nanorod/graphene composite electrocatalysts as reversible metal-air battery electrodes

Energy Technology Data Exchange (ETDEWEB)

Hu, Jie [State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao, 066004 (China); Hebei Key Laboratory of Applied Chemistry, Department of Environment and Chemistry, Yanshan University, Qinhuangdao, 066004 (China); Liu, Qiunan; Shi, Lina; Shi, Ziwei [Hebei Key Laboratory of Applied Chemistry, Department of Environment and Chemistry, Yanshan University, Qinhuangdao, 066004 (China); Huang, Hao, E-mail: huanghao@ysu.edu.cn [State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao, 066004 (China); Henan Huanghe Whirlwind Co. Ltd., Changge, 461500 (China)

2017-04-30

Graphical abstract: Silver decorated LaMnO{sub 3} nanorod/reduced graphene oxide composite possess excellent bifunctional electrocatalytic activity and good electrochemical stability in alkaline medium. - Highlights: • Silver decorated LaMnO{sub 3} nanorod/graphene composite were synthesized for the first time. • The ORR and OER of composite in alkaline medium were evaluated. • This composite as an efficient bifunctional catalyst has a good cycle performance. - Abstract: Perovskite LaMnO{sub 3} nanorod/reduced graphene oxides (LMO-NR/RGO) decorated with Ag nanoparticles are studied as a bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. LMO-NR/RGO composites are synthesized by using cetyltrimethyl ammonium bromide (CTAB) as template via a simple hydrothermal reaction followed by heat treatment; overlaying of Ag nanoparticles is obtained through a traditional silver mirror reaction. Electron microscopy reveals that LMO-NR is embedded between the sheets of RGO, and the material is homogeneously overlaid with Ag nanoparticles. The unique composite morphology of Ag/LMO-NR/RGO not only enhances the electron transport property by increasing conductivity but also facilitates the diffusion of electrolytes and oxygen. As confirmed by electrochemical testing, Ag/LMO-NR/RGO exhibits very strong synergy with Ag nanoparticles, LMO-NR, and RGO, and the catalytic activities of Ag/LMO-NR/RGO during ORR and OER are significantly improved. With the novel catalyst, the homemade zinc-air battery can be reversibly charged and discharged and display a stable cycle performance, indicating the great potential of this composite as an efficient bifunctional electrocatalyst for metal-air batteries.

Coexistence of positive and negative photoconductivity in nickel oxide decorated multiwall carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Jiménez-Marín, E. [Departamento de Ingeniería en Metalurgia y Materiales, Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, Ciudad de México 07300 (Mexico); Villalpando, I. [Centro de Investigación para los Recursos Naturales, Salaices, Chihuahua 33941 (Mexico); Trejo-Valdez, M. [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, México, Ciudad de México 07738 (Mexico); Cervantes-Sodi, F. [Departamento de Física y Matemáticas, Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Ciudad de México 01219 (Mexico); Vargas-García, J.R. [Centro de Nanociencias y Micro y Nanotecnologías del Instituto Politécnico Nacional, Ciudad de México 07738 (Mexico); Torres-Torres, C., E-mail: ctorrest@ipn.mx [Sección de Estudios de Posgrado e Investigación, Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Zacatenco, Instituto Politécnico Nacional, Ciudad de México 07738 (Mexico)

2017-06-15

Highlights: • Nickel oxide decorated carbon nanotubes were prepared by chemical vapor deposition. • Contrast in photoconductivity phenomena in the nanohybrid was analyzed. • Electrical and nonlinear optical properties were evaluated. • A Wheatstone bridge sensor based metal/carbon nanostructures was proposed. - Abstract: Within this work was explored the influence of nickel oxide decoration on the photoconductive effects exhibited by multiwall carbon nanotubes. Samples in thin film form were prepared by a chemical vapor deposition method. Experiments for evaluating the photo-response of the nanomaterials at 532 nanometers wavelength were undertaken. A contrasting behavior in the photoelectrical characteristics of the decorated nanostructures was analyzed. The decoration technique allowed us to control a decrease in photoconduction of the sample from approximately 100 μmhos/cm to −600 μmhos/cm. Two-wave mixing experiments confirmed an enhancement in nanosecond nonlinearities derived by nickel oxide contributions. It was considered that metallic nanoparticles present a strong responsibility for the evolution of the optoelectronic phenomena in metal/carbon nanohybrids. Impedance spectroscopy explorations indicated that a capacitive behavior correspond to the samples. A potential development of high-sensitive Wheatstone bridge sensors based on the optoelectrical performance of the studied samples was proposed.

A new route to produce efficient surface-enhanced Raman spectroscopy substrates: gold-decorated CdSe nanowires

Energy Technology Data Exchange (ETDEWEB)

Das, Gobind; Chakraborty, Ritun; Gopalakrishnan, Anisha [Italian Institute of Technology, Nanostructure Division (Italy); Baranov, Dmitry [University of Colorado at Boulder, Department of Chemistry and Biochemistry (United States); Di Fabrizio, Enzo [King Abdullah University Science and Technology (KAUST), PSE and BESE Divisions (Saudi Arabia); Krahne, Roman, E-mail: roman.krahne@iit.it [Italian Institute of Technology, Nanostructure Division (Italy)

2013-05-15

Surface-enhanced Raman spectroscopy is a popular tool for the detection of extremely small quantities of target molecules. Au nanoparticles have been very successful in this respect due to local enhancement of the light intensity caused by their plasmon resonance. Furthermore, Au nanoparticles are biocompatible, and target substances can be easily attached to their surface. Here, we demonstrate that Au-decorated CdSe nanowires when employed as SERS substrates lead to an enhancement as large as 10{sup 5} with respect to the flat Au surfaces. In the case of hybrid metal-CdSe nanowires, the Au nucleates preferably on lattice defects at the lateral facets of the nanowires, which leads to a homogeneous distribution of Au nanoparticles on the nanowire, and to an efficient quenching of the nanowire luminescence. Moreover, the size of the Au nanoparticles can be well controlled via the AuCl{sub 3} concentration in the fabrication process. We demonstrate the effectiveness of our SERS substrates with two target substances, namely, cresyl-violet and rhodamine-6G. Au-decorated nanowires can be easily fabricated in large quantities at low cost by wet-chemical synthesis. Furthermore, their deposition onto various substrates, as well as the functionalization of these wires with the target substances, is as straightforward as with the traditional markers.

An Injectable Composite Gelatin Hydrogel with pH Response Properties

Directory of Open Access Journals (Sweden)

Baoguo Chen

2017-01-01

Full Text Available On account of minimally invasive procedure and of filling irregular defects of tissues, injectable hydrogels are increasingly attractive in biomedical fields. However, traditional hydrogel formed by simple physical interaction or in situ crosslinking had inevitably some drawbacks such as low mechanical strength and lack of multifunctional properties. Though many investigations had successfully modified traditional injectable hydrogel to obtain both mechanical and functional properties, an acetalated β-cyclodextrin (Ac-β-CD nanoparticle composite injectable hydrogel designed in the research was another effective and efficient choice to solve the drawbacks. First of all, gelatin derivative (G-AA and Ac-β-CD were synthesized to prepare hydrogel and nanoparticle, respectively. In order to ensure good compatibility between nanoparticle and macromonomer and provide crosslink points between nanoparticle and macromonomer, G-AA was simultaneously functionalized onto the surface of Ac-β-CD nanoparticle during the fabrication of Ac-β-CD nanoparticle using one-step method. Finally, injectable composite hydrogel was obtained by photoinitiated polymerization in situ. Hydrogel properties like gelation time and swelling ratio were investigated. The viscoelastic behavior of hydrogels confirmed that typical characteristics of crosslinked elastomer for all hydrogel and nanoparticle in hydrogel could improve the mechanical property of hydrogel. Moreover, the transparency with time had verified obvious acid-response properties of hydrogels.

Gas sensing with gold-decorated vertically aligned carbon nanotubes.

Science.gov (United States)

Mudimela, Prasantha R; Scardamaglia, Mattia; González-León, Oriol; Reckinger, Nicolas; Snyders, Rony; Llobet, Eduard; Bittencourt, Carla; Colomer, Jean-François

2014-01-01

Vertically aligned carbon nanotubes of different lengths (150, 300, 500 µm) synthesized by thermal chemical vapor deposition and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2) at room temperature. Gold nanoparticles of about 6 nm in diameter were sputtered on the top surface of the carbon nanotube forests to enhance the sensitivity to the pollutant gas. We showed that the sensing response to nitrogen dioxide depends on the nanotube length. The optimum was found to be 300 µm for getting the higher response. When the background humidity level was changed from dry to 50% relative humidity, an increase in the response to NO2 was observed for all the sensors, regardless of the nanotube length.

Gas sensing with gold-decorated vertically aligned carbon nanotubes

Directory of Open Access Journals (Sweden)

Prasantha R. Mudimela

2014-06-01

Full Text Available Vertically aligned carbon nanotubes of different lengths (150, 300, 500 µm synthesized by thermal chemical vapor deposition and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2 at room temperature. Gold nanoparticles of about 6 nm in diameter were sputtered on the top surface of the carbon nanotube forests to enhance the sensitivity to the pollutant gas. We showed that the sensing response to nitrogen dioxide depends on the nanotube length. The optimum was found to be 300 µm for getting the higher response. When the background humidity level was changed from dry to 50% relative humidity, an increase in the response to NO2 was observed for all the sensors, regardless of the nanotube length.

Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

Science.gov (United States)

Kumar, Sachin; Chatterjee, Kaushik

2015-01-01

The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium

Formulating gelatin free products

NARCIS (Netherlands)

Buwalda, P.L.

2014-01-01

Gels are applied in many systems in particular in foods. Gelatin is the most common of all gelling agents. In the food industry there is a long quest for replacing gelatin. This chapter focuses on a more application by application approach where a dominant property of gelatin is matched with a

Titania nanotubes decorated with gold nanoparticles for electrochemiluminescent biosensing of glycosylated hemoglobin

Energy Technology Data Exchange (ETDEWEB)

Zhao, Qun [Institute of Analytical Chemistry, Dushu Lake Campus, Soochow University, Industrial Park, Suzhou, 215123 (China); College of Chemistry and Chemical Engineering, Nantong University, Nantong, 226019 (China); Tang, Shan [Institute of Analytical Chemistry, Dushu Lake Campus, Soochow University, Industrial Park, Suzhou, 215123 (China); Fang, Chen [Institute of Analytical Chemistry, Dushu Lake Campus, Soochow University, Industrial Park, Suzhou, 215123 (China); Second Affiliated Hospital, Soochow University, Suzhou, 215004 (China); Tu, Yi-Feng, E-mail: tuyf@suda.edu.cn [Institute of Analytical Chemistry, Dushu Lake Campus, Soochow University, Industrial Park, Suzhou, 215123 (China)

2016-09-14

A glycated hemoglobin (HbA1c) biosensor with high performance has been constructed in this work. Here the fructosyl amino acid oxidase was immobilized onto a pre-functionalized indium tin oxide glass with titania nanotubes decorated with gold nanoparticles. The property of nanocomposite was characterized by transmission electromicroscopy, scanning electron microscopy, electrochemistry and spectroscopy. Under the optimum conditions, fructosyl valine was detected by this biosensor. It exhibited a linear detection range from 4.0 × 10{sup −9} M to 7.2 × 10{sup −7} M, and a limit of detection for 3.8 × 10{sup −9} M at the signal-to-noise ratio of 3. Thus the HbA1c level in whole blood samples of healthy individuals or diabetic patients were evaluated with designed biosensor after pre-treatment of hydrolysis. The results of our detection were closely consistent with that of the standard method. At the same time, our biosensor has some advantages including high sensitivity, disposable usage and low cost, which implies its great promising application in point-of-care testing of HbA1c. - Highlights: • The enhanced electrochemiluminescence of luminol by AuNPs/TiNTs. • An ECL biosensor for HbA1c assay with ultra-high sensitivity. • A promising disposable device for diabetic diagnosis and treatment even for POCT. • The excellent regression of detected results with gold-standard method.

Titania nanotubes decorated with gold nanoparticles for electrochemiluminescent biosensing of glycosylated hemoglobin

International Nuclear Information System (INIS)

Zhao, Qun; Tang, Shan; Fang, Chen; Tu, Yi-Feng

2016-01-01

A glycated hemoglobin (HbA1c) biosensor with high performance has been constructed in this work. Here the fructosyl amino acid oxidase was immobilized onto a pre-functionalized indium tin oxide glass with titania nanotubes decorated with gold nanoparticles. The property of nanocomposite was characterized by transmission electromicroscopy, scanning electron microscopy, electrochemistry and spectroscopy. Under the optimum conditions, fructosyl valine was detected by this biosensor. It exhibited a linear detection range from 4.0 × 10"−"9 M to 7.2 × 10"−"7 M, and a limit of detection for 3.8 × 10"−"9 M at the signal-to-noise ratio of 3. Thus the HbA1c level in whole blood samples of healthy individuals or diabetic patients were evaluated with designed biosensor after pre-treatment of hydrolysis. The results of our detection were closely consistent with that of the standard method. At the same time, our biosensor has some advantages including high sensitivity, disposable usage and low cost, which implies its great promising application in point-of-care testing of HbA1c. - Highlights: • The enhanced electrochemiluminescence of luminol by AuNPs/TiNTs. • An ECL biosensor for HbA1c assay with ultra-high sensitivity. • A promising disposable device for diabetic diagnosis and treatment even for POCT. • The excellent regression of detected results with gold-standard method.

Facile synthesis of zinc oxide nanoparticles decorated graphene oxide composite via simple solvothermal route and their photocatalytic activity on methylene blue degradation.

Science.gov (United States)

Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel; Perumal, Suguna; Karthikeyan, Dhanapalan; Lee, Yong Rok

2016-09-01

Zinc oxide nanoparticles decorated graphene oxide (ZnO@GO) composite was synthesized by simple solvothermal method where zinc oxide (ZnO) nanoparticles and graphene oxide (GO) were synthesized via simple thermal oxidation and Hummers method, respectively. The obtained materials were thoroughly characterized by various physico-chemical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Raman spectrum shows the intensity of D to G value was close to one which confirms the obtained GO and ZnO@GO composite possesses moderate graphitization. TEM images shows the ZnO nanoparticles mean size of 15±5nm were dispersed over the wrinkled graphene layers. The photocatalytic performance of ZnO@GO composite on degradation of methylene blue (MB) is investigated and the results show that the GO plays an important role in the enhancement of photocatalytic performance. The synthesized ZnO@GO composite achieves a maximum degradation efficiency of 98.5% in a neutral solution under UV-light irradiation for 15min as compared with pure ZnO (degradation efficiency is 49% after 60min of irradiation) due to the increased light absorption, the reduced charge recombination with the introduction of GO. Moreover, the resulting ZnO@GO composite possesses excellent degradation efficiency as compared to ZnO nanoparticles alone on MB. Copyright © 2016 Elsevier B.V. All rights reserved.

Biosensor Based on Tyrosinase Immobilized on Graphene-Decorated Gold Nanoparticle/Chitosan for Phenolic Detection in Aqueous

Directory of Open Access Journals (Sweden)

Fuzi Mohamed Fartas

2017-05-01

Full Text Available In this research work, electrochemical biosensor was fabricated based on immobilization of tyrosinase onto graphene-decorated gold nanoparticle/chitosan (Gr-Au-Chit/Tyr nanocomposite-modified screen-printed carbon electrode (SPCE for the detection of phenolic compounds. The nanocomposite film was constructed via solution casting method. The electrocatalytic activity of the proposed biosensor for phenol detection was studied using differential pulse voltammetry (DPV and cyclic voltammetry (CV. Experimental parameters such as pH buffer, enzyme concentration, ratio of Gr-Au-Chit, accumulation time and potential were optimized. The biosensor shows linearity towards phenol in the concentration range from 0.05 to 15 μM with sensitivity of 0.624 μA/μM and the limit of detection (LOD of 0.016 μM (S/N = 3. The proposed sensor also depicts good reproducibility, selectivity and stability for at least one month. The biosensor was compared with high-performance liquid chromatography (HPLC method for the detection of phenol spiked in real water samples and the result is in good agreement and comparable.

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

Directory of Open Access Journals (Sweden)

Hamza A. Asmaly

2015-09-01

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

MoS2 nanosheet functionalized with Cu nanoparticles and its application for glucose detection

International Nuclear Information System (INIS)

Huang, Jingwei; Dong, Zhengping; Li, Yanrong; Li, Jing; Tang, Weijie; Yang, Haidong; Wang, Jia; Bao, Yun; Jin, Jun; Li, Rong

2013-01-01

Graphical abstract: - Highlights: • First report on decorating MoS 2 nanosheet with Cu nanoparticles by chemical reduction. • Cu nanoparticles were uniformly decorated on MoS 2 nanosheet. • Glucose biosensor based on copper nanoparticles-MoS 2 nanosheet hybrid is fabricated. • The biosensor exhibits high sensitivity. - Abstract: For the first time, Cu nanoparticles were evenly decorated on MoS 2 nanosheet by chemical reduction. The as-prepared Cu-MoS 2 hybrid was characterized by atomic force microscope (AFM), Raman spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and then used to fabricate a non-enzymatic glucose sensor. The performance of our sensor was investigated by cyclic voltammetry and amperometric measurement in alkaline media. Electrochemical tests showed that Cu-MoS 2 hybrid exhibited synergistic electrocatalytic activity on the oxidation of glucose with a high sensitivity of 1055 μA mM −1 cm −2 and a linear range up to 4 mM

Palladium nanoparticles anchored on graphene nanosheets: Methanol, ethanol oxidation reactions and their kinetic studies

Energy Technology Data Exchange (ETDEWEB)

Nagaraju, D.H., E-mail: dhnagu@gmail.com [Department of Mechanical Engineering, 117 576 (Singapore); Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 (Saudi Arabia); Devaraj, S. [Department of Mechanical Engineering, 117 576 (Singapore); School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 401 (India); Balaya, P., E-mail: mpepb@nus.edu.sg [Department of Mechanical Engineering, 117 576 (Singapore); Engineering Science Program, National University of Singapore, 117 576 (Singapore)

2014-12-15

Highlights: • Palladium nanoparticles decorated graphene is synthesized in a single step. • Electro-catalytic activity of Gra/Pd toward alcohol oxidation is evaluated. • 1:1 Gra/Pd exhibits good electro-catalytic activity and efficient electron transfer. - Abstract: Palladium nanoparticles decorated graphene (Gra/Pd nanocomposite) was synthesized by simultaneous chemical reduction of graphene oxide and palladium salt in a single step. The negatively charged graphene oxide (GO) facilitates uniform distribution of Pd{sup 2+} ions onto its surface. The subsequent reduction by hydrazine hydrate provides well dispersed Pd nanoparticles decorated graphene. Different amount of Pd nanoparticles on graphene was synthesized by changing the volume to weight ratio of GO to PdCl{sub 2}. X-ray diffraction studies showed FCC lattice of Pd with predominant (1 1 1) plane. SEM and TEM studies revealed that thin graphene nanosheets are decorated by Pd nanoparticles. Raman spectroscopic studies revealed the presence of graphene nanosheets. The electro-catalytic activity of Gra/Pd nanocomposites toward methanol and ethanol oxidation in alkaline medium was evaluated by cyclic voltammetric studies. 1:1 Gra/Pd nanocomposite exhibited good electro-catalytic activity and efficient electron transfer. The kinetics of electron transfer was studied using chronoamperometry. Improved electro-catalytic activity of 1:1 Gra/Pd nanocomposite toward alcohol oxidation makes it as a potential anode for the alcohol fuel cells.

Palladium nanoparticles anchored on graphene nanosheets: Methanol, ethanol oxidation reactions and their kinetic studies

International Nuclear Information System (INIS)

Nagaraju, D.H.; Devaraj, S.; Balaya, P.

2014-01-01

Highlights: • Palladium nanoparticles decorated graphene is synthesized in a single step. • Electro-catalytic activity of Gra/Pd toward alcohol oxidation is evaluated. • 1:1 Gra/Pd exhibits good electro-catalytic activity and efficient electron transfer. - Abstract: Palladium nanoparticles decorated graphene (Gra/Pd nanocomposite) was synthesized by simultaneous chemical reduction of graphene oxide and palladium salt in a single step. The negatively charged graphene oxide (GO) facilitates uniform distribution of Pd 2+ ions onto its surface. The subsequent reduction by hydrazine hydrate provides well dispersed Pd nanoparticles decorated graphene. Different amount of Pd nanoparticles on graphene was synthesized by changing the volume to weight ratio of GO to PdCl 2 . X-ray diffraction studies showed FCC lattice of Pd with predominant (1 1 1) plane. SEM and TEM studies revealed that thin graphene nanosheets are decorated by Pd nanoparticles. Raman spectroscopic studies revealed the presence of graphene nanosheets. The electro-catalytic activity of Gra/Pd nanocomposites toward methanol and ethanol oxidation in alkaline medium was evaluated by cyclic voltammetric studies. 1:1 Gra/Pd nanocomposite exhibited good electro-catalytic activity and efficient electron transfer. The kinetics of electron transfer was studied using chronoamperometry. Improved electro-catalytic activity of 1:1 Gra/Pd nanocomposite toward alcohol oxidation makes it as a potential anode for the alcohol fuel cells

Gold nanoparticles-decorated electrospun poly(N-vinyl-2-pyrrolidone) nanofibers with tunable size and coverage density for nanomolar detection of single and binary component dyes by surface-enhanced raman spectroscopy

Science.gov (United States)

Kurniawan, Alfin; Wang, Meng-Jiy

2017-09-01

The application of the electrospun nanomaterials to surface-enhanced Raman spectroscopy (SERS) is a rapidly evolving field which holds potential for future developments in the generation of portable plasmonic-based detection platforms. In this study, a simple approach to fabricate electrospun poly(N-vinylpyrrolidone) (PVP) mats decorated with gold nanoparticles (AuNPs) by combining electrospinning and calcination was presented. AuNPs were decorated on the fiber mat surface through electrostatic interactions between positively charged aminosilane groups and negatively charged AuNPs. The size and coverage density of AuNPs on the fiber mats could be tuned by varying the calcination temperature. Calcination of AuNPs-decorated PVP fibers at 500 °C-700 °C resulted in the uniform decoration of high density AuNPs with very narrow gaps on every single fiber, which in turn contribute to strong electromagnetic SERS enhancement. The robust free-standing AuNPs-decorated mat which calcined at 500 °C (500/AuNPs-F) exhibited high SERS activity toward cationic (methylene blue, MB) and anionic (methyl orange, MO) dyes in single and binary systems with a detection range from tens of nM to a few hundred μM. The fabricated SERS substrate demonstrated high reproducibility with the spot-to-spot variation in SERS signal intensities was ±10% and ±12% for single and binary dye systems, respectively. The determination of MB and MO in spiked river water and tap water with 500/AuNPs-F substrate gave satisfactory results in terms of the percent spike recoveries (ranging from 92.6%-96.6%) and reproducibility (%RSD values less than 15 for all samples).

The Incidence and Fate of Volatile Methyl Siloxanes in a Crewed Spacecraft Cabin

Science.gov (United States)

Perry, Jay L.; Kayatin, Matthew J.

2017-01-01

Volatile methyl siloxanes (VMS) arise from diverse, pervasive sources aboard crewed spacecraft ranging from materials offgassing to volatilization from personal care products. These sources lead to a persistent VMS compound presence in the cabin environment that must be considered for robust life support system design. Volatile methyl siloxane compound stability in the cabin environment presents an additional technical issue because degradation products such as dimethylsilanediol (DMSD) are highly soluble in water leading to a unique load challenge for water purification processes. The incidence and fate of VMS compounds as observed in the terrestrial atmosphere, water, and surface (soil) environmental compartments have been evaluated as an analogy for a crewed cabin environment. Volatile methyl siloxane removal pathways aboard crewed spacecraft are discussed and a material balance accounting for a DMSD production mechanism consistent with in-flight observations is presented.

Gelatin/chitosan biofilm: preparation and characterization

International Nuclear Information System (INIS)

Trindade, Luciane da C.; Nunes, Raquel A.; Diniz, Nadie K.S.; Braga, Carla R.C.; Silva, Suedina M. de Lima

2011-01-01

In this study, gelatin, chitosan and gelatin/chitosan bio films using the ratio of gelatin/chitosan (50/50) were prepared by casting method. The bio films prepared were characterized by X-ray diffraction, scanning electron microscopy and dissolution ratio. According to the results, the incorporation of chitosan into gelatin indicate the decrease of crystallinity of chitosan, a compact structure without large pores and that the dissolution of gelatin/chitosan film is little influenced by hot water than gelatin films. (author)

Porous TiO{sub 2} nanofibers decorated CdS nanoparticles by SILAR method for enhanced visible-light-driven photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Tian, Fengyu; Hou, Dongfang, E-mail: dfhouok@126.com; Hu, Fuchao; Xie, Kui; Qiao, Xiuqing; Li, Dongsheng, E-mail: lidongsheng1@126.com

2017-01-01

Graphical abstract: A heterojunction photocatalyst with CdS Nanoparticles self-assembled via SILAR Method at surfaces of electrospun TiO2 nanofibers shows enhanced visible-light photocatalytic activities. - Highlights: • Combined electrospinning and successive ionic layer adsorption and reaction process. • Pouous TiO{sub 2} nanofibers decorated CdS nanoparticles. • Synergetic effect of photosensitization and heterojunction. - Abstract: 1D porous CdS nanoparticles/TiO{sub 2} nanofibers heterostructure has been fabricated via simple electrospinning and a successive ionic layer adsorption and reaction (SILAR) process. The morphology, composition, and optical properties of the resulting CdS/TiO{sub 2} heterostructures can be rationally tailored through changing the SILAR cycles. The photocatalytic hydrogen evolution and decomposition of rhodamine B (RhB) of the as-synthesized heterostructured photocatalysts were investigated under visible light irradiation. Compared to TiO{sub 2} nanofibers，the as-obtained CdS/TiO{sub 2} heterostructures exhibit enhanced photocatalytic activity for hydrogen production and decomposition of RhB under visible-light irradiation. The heterojunction system performs best with H{sub 2} generation rates of 678.61 μmol h{sup −1} g{sup −1} under visible light irradiation which benefits from the two effects: (a) the 1D porous nanofibrous morphology contributes to not only more active sites but also more efficient transfer of the photogenerated charges (b) the synergetic effect of heterojunction and photosensitization reducing the recombination of photogenerated electrons and holes.

Gold nanoparticles decorated on BaTiO3 as photocatalyst: effect of SPR and ferroelectricity

Science.gov (United States)

Miao, Zhilei; Chen, Lei; Wang, Rui; Yuan, Rongchun; Zhou, Fang; Lv, Pengfei; Zhang, Xiuyun; Wang, Qiang

2018-02-01

BaTiO3(BTO) powders with cubic(C) and tetragonal(T) crystalline structures were prepared by sol-gel method followed by calcination at different temperatures, and they were decorated with gold nanoparticles(AuNPs) to form Au-T-BTO and Au-C-BTO respectively. All the samples (C-BTO, T-BTO, Au-C-BTO and Au-T-BTO) were used as photo-catalysts for the degradation of Rhodamine B (RhB). Au-T-BTO exhibits the highest photocatalytic activity due to thecombined effect of surface plasmon resonance (SPR) and the ferroelectricity of the tetragonalphase BTO. The light absorption peaks at 500 to 600 nm verify the presence of SPR effect from Au NPs. Based on density functional theory (DFC) within the generalized gradient approximation (GGA) approach, it was demonstrated that the tetragonal phase BaTiO3 shows a spontaneous polarization with the calculated value of 0.34 C m-2, which is absent in thecubic phase. The internal space charge layer in tetragonal phase BTO enhances the separation of photoexcited carriers due to the spontaneous ferroelectric polarization, which also benefits photocatalytic activities.

Synthesis and characterization of silver nanoparticles: effect on phytopathogen Colletotrichum gloesporioides

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Mendez, Miguel A., E-mail: maguilarme@ipn.mx; San Martin-Martinez, Eduardo; Ortega-Arroyo, Lesli [Instituto Politecnico Nacional, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (Mexico); Cobian-Portillo, Georgina [Instituto Politecnico Nacional, Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional (Mexico); Sanchez-Espindola, Esther [Instituto Politecnico Nacional, Escuela Nacional de Ciencias Biologicas, Prolongacion Manuel M. Carpio s/n, esq. Plan de Ayala (Mexico)

2011-06-15

Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin as capping agent. The obtained nanoparticles were characterized by means of UV-Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV-Vis spectra indicated the formation of silver nanoparticles preferably spherical and of relatively small size (<20 nm). The above-mentioned was confirmed by TEM, observing a size distribution of 5-24 nm. According to RSM the synthesis variables influenced on the size of the silver nanoparticles. By means of FTIR spectroscopy it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration. The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner.

Synthesis and characterization of silver nanoparticles: effect on phytopathogen Colletotrichum gloesporioides

International Nuclear Information System (INIS)

Aguilar-Méndez, Miguel A.; San Martín-Martínez, Eduardo; Ortega-Arroyo, Lesli; Cobián-Portillo, Georgina; Sánchez-Espíndola, Esther

2011-01-01

Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin as capping agent. The obtained nanoparticles were characterized by means of UV–Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV–Vis spectra indicated the formation of silver nanoparticles preferably spherical and of relatively small size (<20 nm). The above-mentioned was confirmed by TEM, observing a size distribution of 5–24 nm. According to RSM the synthesis variables influenced on the size of the silver nanoparticles. By means of FTIR spectroscopy it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration. The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner.

Green Synthesis of Silver Nanoparticles and the Study of Optical Properties

Directory of Open Access Journals (Sweden)

Ramakrishna Vasireddy

2012-08-01

Full Text Available The synthesis of silver nanoparticles of varying size has been achieved using different molar concentrations of NaOH while the effect of changing the temperature has been studied. AgNO3, gelatine, glucose and NaOH are used as a silver precursor, stabilizer, reducing agent and accelerator respectively. The synthesized nanoparticles have been characterized by a FESEM study, X‐ray diffractometry, Raman spectroscopy and UV‐vis spectroscopy. The colloidal sols of the silver nanoparticles in a biopolymer gelatine show strong surface plasmon resonance absorption peaks. The visible photoluminescence emission from the synthesized silver nanocrystals has been recorded within the wavelength range of 400‐600 nm under UV excitation. The synthesized nanoparticles may be extremely useful in making biosensor devices as well as for other applications.

An approach for scalable production of silver (Ag) decorated WS2 nanosheets

Science.gov (United States)

Sumesh, C. K.; Kapatel, Sanni; Chaudhari, Arti

2018-05-01

In the Present study we report the synthesis of Ag nanoparticles (NPs) decorated WS2 nanosheets by sonochemical exfoliation followed by simple chemical reduction process at room temperature. The morphology and microstructure of the as-synthesized Ag-WS2 nanocomposite were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and optical absorption (UV-Vis.) spectroscopy. X-ray and TEM analysis shows the presence of Ag with significant peak over 38.08°, 44.22°, 64.37° and 77.33° at 2θ angle for (111), (200), (220) and (311) respectively. The Ag nanoparticles are randomly distributed throughout the surface of the WS2 nanosheets without undergoing further oxidation during the formation of composites. The formation of Ag-WS2 nanocomposites shows a clear blue shift in the absorption as we obtained the characteristics absorption valleys at 456, 536 and 631 nm from the UV Vis spectroscopy analysis compared to pure WS2 nanosheets. Henceforth a facile method for the Ag decoration on WS2 nanosheets was put forward and briefly discussed. The proposed synthesis method is very promising for the low cost and large-scale synthesis of other noble metal incorporation TMDC compounds.

Uniform Gold-Nanoparticle-Decorated {001}-Faceted Anatase TiO2 Nanosheets for Enhanced Solar-Light Photocatalytic Reactions.

Science.gov (United States)

Shi, Huimin; Zhang, Shi; Zhu, Xupeng; Liu, Yu; Wang, Tao; Jiang, Tian; Zhang, Guanhua; Duan, Huigao

2017-10-25

The {001}-faceted anatase TiO 2 micro-/nanocrystals have been widely investigated for enhancing the photocatalysis and photoelectrochemical performance of TiO 2 nanostructures, but their practical applications still require improved energy conversion efficiency under solar-light and enhanced cycling stability. In this work, we demonstrate the controlled growth of ultrathin {001}-faceted anatase TiO 2 nanosheets on flexible carbon cloth for enhancing the cycling stability, and the solar-light photocatalytic performance of the synthesized TiO 2 nanosheets can be significantly improved by decorating with vapor-phase-deposited uniformly distributed plasmonic gold nanoparticles. The fabricated Au-TiO 2 hybrid system shows an 8-fold solar-light photocatalysis enhancement factor in photodegrading Rhodamine B, a high photocurrent density of 300 μA cm -2 under the illumination of AM 1.5G, and 100% recyclability under a consecutive long-term cycling measurement. Combined with electromagnetic simulations and systematic control experiments, it is believed that the tandem-type separation and transition of plasmon-induced hot electrons from Au nanoparticles to the {001} facet of anatase TiO 2 , and then to the neighboring {101} facet, is responsible for the enhanced solar-light photochemical performance of the hybrid system. The Au-TiO 2 nanosheet system addresses well the problems of the limited solar-light response of anatase TiO 2 and fast recombination of photogenerated electron-hole pairs, representing a promising high-performance recyclable solar-light-responding system for practical photocatalytic reactions.

A novel enzymatic glucose sensor based on Pt nanoparticles-decorated hollow carbon spheres-modified glassy carbon electrode

Energy Technology Data Exchange (ETDEWEB)

Luhana, Charles; Bo Xiangjie; Ju Jian; Guo Liping, E-mail: guolp078@nenu.edu.cn [Northeast Normal University, Faculty of Chemistry (China)

2012-10-15

A new glucose biosensor was developed based on hollow carbon spheres decorated with platinum nanoparticles (Pt/HCSs)-modified glassy carbon electrode immobilized with glucose oxidase (GOx) with the help of Nafion. The Pt nanoparticles were well dispersed on the HCSs with an average size of 2.29 nm. The detection of glucose was achieved via electrochemical detection of the enzymatically liberated H{sub 2}O{sub 2} at +0.5 V versus Ag/AgCl at physiologic pH of 7.4. The Pt/HCSs-modified electrode exhibited excellent electrocatalytic activities toward both the oxidation and reduction of H{sub 2}O{sub 2}. The glucose biosensor showed good electrocatalytic performance in terms of high sensitivity (4.1 {mu}A mM{sup -1}), low detection limit (1.8 {mu}M), fast response time <3 s, and wide linear range (0.04-8.62 mM). The apparent Michaelis-Menten constant (K{sub m}) and the maximum current density (i{sub max}) values for the biosensor were 10.94 mM and 887 {mu}A cm{sup -2} respectively. Furthermore, this biosensor showed an acceptable reproducibility and high stability. The interfering signals from ascorbic acid and uric acid at concentration levels normally found in human blood were not much compared with the response to glucose. Blood serum samples were also tested with this biosensor and a good recovery was achieved for the two spiked serum samples.

Dynamics of magnetic nanoparticles in viscoelastic media

Energy Technology Data Exchange (ETDEWEB)

Remmer, Hilke, E-mail: h.remmer@tu-bs.de [Institute of Electrical Measurement and Fundamental Electrical Engineering, TU Braunschweig, Braunschweig (Germany); Roeben, Eric; Schmidt, Annette M. [Institute of Physical Chemistry, Universität zu Köln, Köln (Germany); Schilling, Meinhard; Ludwig, Frank [Institute of Electrical Measurement and Fundamental Electrical Engineering, TU Braunschweig, Braunschweig (Germany)

2017-04-01

We compare different models for the description of the complex susceptibility of magnetic nanoparticles in an aqueous gelatin solution representing a model system for a Voigt-Kelvin scheme. The analysis of susceptibility spectra with the numerical model by Raikher et al. is compared with the analysis applying a phenomenological, modified Debye model. The fit of the models to the measured data allows one to extract the viscoelastic parameter dynamic viscosity η and shear modulus G. The experimental data were recorded on single-core thermally blocked CoFe{sub 2}O{sub 4} nanoparticles in an aqueous solution with 2.5 wt% gelatin. Whereas the dynamic viscosities obtained by fitting the model – extended by distributions of hydrodynamic diameters and viscosities – agree very well, the derived values for the shear modulus show the same temporal behavior during the gelation process, but vary approximately by a factor of two. To verify the values for viscosity and shear modulus obtained from nanorheology, macrorheological measurements are in progress. - Highlights: • Ac susceptibility spectra of CoFe2O4 nanoparticles in aqueous gelatin solution. • Analysis of spectra with different approaches of Voigt-Kelvin model. • Comparison of modified Debye model with numerical model. • Both models provide similar values for viscoelastic parameters.

Enhanced Photocatalytic Performance of NiO-Decorated ZnO Nanowhiskers for Methylene Blue Degradation

Directory of Open Access Journals (Sweden)

I. Abdul Rahman

2014-01-01

Full Text Available ZnO nanowhiskers were used for photodecomposition of methylene blue in aqueous solution under UV irradiation. The rate of methylene blue degradation increased linearly with time of UV irradiation. 54% of degradation rate was observed when the ZnO nanowhiskers were used as photocatalysts for methylene blue degradation for 80 min under UV irradiation. The decoration of p-type NiO nanoparticles on n-type ZnO nanowhiskers significantly enhanced photocatalytic activity and reached 72% degradation rate of methylene blue by using the same method. NiO-decorated ZnO was recycled for second test and shows 66% degradation from maximal peak of methylene blue within the same period. The increment of photocatalytic activity of NiO-decorated ZnO nanowhiskers was explained by the extension of the electron depletion layer due to the formation of nanoscale p-n junctions between p-type NiO and n-type ZnO. Hence, these products provide new alternative proficient photocatalysts for wastewater treatment.

Efficient 2-Nitrophenol Chemical Sensor Development Based on Ce2O3 Nanoparticles Decorated CNT Nanocomposites for Environmental Safety.

Directory of Open Access Journals (Sweden)

Mohammad M Hussain

Full Text Available Ce2O3 nanoparticle decorated CNT nanocomposites (Ce2O3.CNT NCs were prepared by a wet-chemical method in basic medium. The Ce2O3.CNT NCs were examined using FTIR, UV/Vis, Field-Emission Scanning Electron Microscopy (FESEM, X-ray electron dispersive spectroscopy (XEDS, X-ray photoelectron spectroscopy (XPS, and powder X-ray diffraction (XRD. A selective 2-nitrophenol (2-NP sensor was developed by fabricating a thin-layer of NCs onto a flat glassy carbon electrode (GCE, surface area = 0.0316 cm2. Higher sensitivity including linear dynamic range (LDR, long-term stability, and enhanced electrochemical performances towards 2-NP were achieved by a reliable current-voltage (I-V method. The calibration curve was found linear (R2 = 0.9030 over a wide range of 2-NP concentration (100 pM ~ 100.0 mM. Limit of detection (LOD and sensor sensitivity were calculated based on noise to signal ratio (~3N/S as 60 ± 0.02 pM and 1.6×10-3 μAμM-1cm-2 respectively. The Ce2O3.CNT NCs synthesized by a wet-chemical process is an excellent way of establishing nanomaterial decorated carbon materials for chemical sensor development in favor of detecting hazardous compounds in health-care and environmental fields at broad-scales. Finally, the efficiency of the proposed chemical sensors can be applied and utilized in effectively for the selective detection of toxic 2-NP component in environmental real samples with acceptable and reasonable results.

A new route to produce efficient surface-enhanced Raman spectroscopy substrates: Gold-decorated CdSe nanowires

KAUST Repository

Das, Gobind

2013-04-13

Surface-enhanced Raman spectroscopy is a popular tool for the detection of extremely small quantities of target molecules. Au nanoparticles have been very successful in this respect due to local enhancement of the light intensity caused by their plasmon resonance. Furthermore, Au nanoparticles are biocompatible, and target substances can be easily attached to their surface. Here, we demonstrate that Au-decorated CdSe nanowires when employed as SERS substrates lead to an enhancement as large as 105 with respect to the flat Au surfaces. In the case of hybrid metal-CdSe nanowires, the Au nucleates preferably on lattice defects at the lateral facets of the nanowires, which leads to a homogeneous distribution of Au nanoparticles on the nanowire, and to an efficient quenching of the nanowire luminescence. Moreover, the size of the Au nanoparticles can be well controlled via the AuCl3 concentration in the fabrication process. We demonstrate the effectiveness of our SERS substrates with two target substances, namely, cresyl-violet and rhodamine-6G. Au-decorated nanowires can be easily fabricated in large quantities at low cost by wet-chemical synthesis. Furthermore, their deposition onto various substrates, as well as the functionalization of these wires with the target substances, is as straightforward as with the traditional markers. © 2013 Springer Science+Business Media Dordrecht.

A new route to produce efficient surface-enhanced Raman spectroscopy substrates: Gold-decorated CdSe nanowires

KAUST Repository

Das, Gobind; Chakraborty, Ritun; Gopalakrishnan, Anisha; Baranov, Dmitry; Di Fabrizio, Enzo M.; Krahne, Roman

2013-01-01

Surface-enhanced Raman spectroscopy is a popular tool for the detection of extremely small quantities of target molecules. Au nanoparticles have been very successful in this respect due to local enhancement of the light intensity caused by their plasmon resonance. Furthermore, Au nanoparticles are biocompatible, and target substances can be easily attached to their surface. Here, we demonstrate that Au-decorated CdSe nanowires when employed as SERS substrates lead to an enhancement as large as 105 with respect to the flat Au surfaces. In the case of hybrid metal-CdSe nanowires, the Au nucleates preferably on lattice defects at the lateral facets of the nanowires, which leads to a homogeneous distribution of Au nanoparticles on the nanowire, and to an efficient quenching of the nanowire luminescence. Moreover, the size of the Au nanoparticles can be well controlled via the AuCl3 concentration in the fabrication process. We demonstrate the effectiveness of our SERS substrates with two target substances, namely, cresyl-violet and rhodamine-6G. Au-decorated nanowires can be easily fabricated in large quantities at low cost by wet-chemical synthesis. Furthermore, their deposition onto various substrates, as well as the functionalization of these wires with the target substances, is as straightforward as with the traditional markers. © 2013 Springer Science+Business Media Dordrecht.

Hierarchical top-porous/bottom-tubular TiO 2 nanostructures decorated with Pd nanoparticles for efficient photoelectrocatalytic decomposition of synergistic pollutants

KAUST Repository

Zhang, Zhonghai

2012-02-22

In this paper, top-porous and bottom-tubular TiO 2 nanotubes (TiO 2 NTs) loaded with palladium nanoparticles (Pd/TiO 2 NTs) were fabricated as an electrode for an enhanced photoelectrocatalytic (PEC) activity toward organic dye decomposition. TiO 2 NTs with a unique hierarchical top-porous and bottom-tubular structure were prepared by a facile two-step anodization method and Pd nanoparticles were decorated onto the TiO 2 NTs via a photoreduction process. The PEC activity of Pd/TiO 2 NTs was investigated by decomposition of methylene blue (MB) and Rhodamine B (RhB). Because of formation Schottky junctions between TiO 2 and Pd, which significantly promoted the electron transfer and reduced the recombination of photogenerated electrons and holes, the Pd/TiO 2 NT electrode showed significantly higher PEC activities than TiO 2 NTs. Interestingly, an obvious synergy between two dyes was observed and corresponding mechanism based on facilitated transfer of electrons and holes as a result of a suitable energy level alignment was suggested. The findings of this work provide a fundamental insight not only into the fabrication but also utility of Schottky junctions for enhanced environmental remediation processes. © 2012 American Chemical Society.

A gold electrode modified with silver oxide nanoparticle decorated carbon nanotubes for electrochemical sensing of dissolved ammonia

International Nuclear Information System (INIS)

Rahman, Mohammed M.; Asiri, Abdullah M.; Balkhoyor, Hasan B.; Marwani, Hadi M.

2016-01-01

We have prepared silver oxide nanoparticles with a diameter of ∼ 15 nm and decorated with carbon nanotube nanocomposites (Ag_2O/CNT NCs) by a facile wet chemical method using reducing agents in alkaline medium. These NCs were characterized by UV/vis, FTIR and energy dispersive X-ray spectroscopy, by X-ray powder diffraction and field emission scanning electron microscopy. The NCs were then deposited on a flat gold electrode with the help of a conducting binder to result in an electrochemical sensor for aqueous ammonia using the I-V technique. Response is based on surface oxidation of ammonium hydroxide with electrode-adsorbed oxygen to form nitrogen oxide, these simultaneously liberating free electrons in the conduction band. Sensor features include a sensitivity of 32.856 μA.μM"-"1.cm"-"2, a low detection limit (1.3 pM at a signal to noise ratio of 3), reliability, reproducibility, ease of integration, and long term stability. The response to dissolved ammonia is linear (r"2: 0.9778) over the 0.01 nM to 0.1 mM concentration range. (author)

Molecular beacon-based real-time PCR method for detection of porcine DNA in gelatin and gelatin capsules.

Science.gov (United States)

Mohamad, Nurhidayatul Asma; Mustafa, Shuhaimi; Khairil Mokhtar, Nur Fadhilah; El Sheikha, Aly Farag

2018-03-05

The pharmaceutical industry has boosted gelatin consumption worldwide. This is supported by the availability of cost-effective gelatin production from porcine by-products. However, cross-contamination of gelatin materials, where porcine gelatin was unintentionally included in the other animal sources of gelatin, has caused significant concerns about halal authenticity. The real-time polymerase chain reaction (PCR) has enabled a highly specific and sensitive animal species detection method in various food products. Hence, such a technique was employed in the present study to detect and quantify porcine DNA in gelatin using a molecular beacon probe, with differences in performance between mitochondrial (cytochrome b gene) and chromosomal DNA-(MPRE42 repetitive element) based porcine-specific PCR assays being compared. A higher sensitivity was observed in chromosomal DNA (MPRE-PCR assay), where this assay allows the detection of gelatin DNA at amounts as as low as 1 pg, whereas mitochondrial DNA (CBH-PCR assay) can only detect at levels down to 10 pg of gelatin DNA. When an analysis with commercial gelatin and gelatin capsule samples was conducted, the same result was observed, with a significantly more sensitive detection being provided by the repetitive element of chromosomal DNA. The present study has established highly sensitive DNA-based porcine detection systems derived from chromosomal DNA that are feasible for highly processed products such as gelatin and gelatin capsules containing a minute amount of DNA. This sensitive detection method can also be implemented to assist the halal authentication process of various food products available on the market. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Silver-gelatine bionanocomposites for qualitative detection of a pesticide by SERS.

Science.gov (United States)

Fateixa, S; Soares, S F; Daniel-da-Silva, A L; Nogueira, H I S; Trindade, T

2015-03-07

The controlled release of pesticides using hydrogel vehicles is an important procedure to limit the amount of these compounds in the environment, providing an effective way for crop protection. A key-step in the formulation of new materials for these purposes encompasses the monitoring of available pesticides in the gel matrix under variable working conditions. In this work, we report a series of bionanocomposites made of Ag nanoparticles (NPs) and gelatine A for the surface enhanced Raman scattering (SERS) detection of sodium diethyldithiocarbamate (EtDTC) as a pesticide model. These studies demonstrate the effectiveness of these substrates for the detection of EtDTC in aqueous solutions in a concentration as low as 10(-5) M. We have monitored the Raman signal enhancement of this analyte in bionanocomposites having an increasing amount of gelatine due to their relevance in formulating hydrogels of variable gel strengths. Under these conditions, the bionanocomposites have shown an effective SERS activity using EtDTC, demonstrating their effectiveness in the qualitative detection of this analyte. Finally, experiments involving the release of EtDTC from Ag/gelatine samples have been monitored by SERS, which attest the potential of this spectroscopic method in the laboratorial monitoring of hydrogels for pesticide release.

Photochemical decoration of silver nanoparticles on graphene oxide nanosheets and their optical characterization

Energy Technology Data Exchange (ETDEWEB)

Lan, Nguyen Thi; Chi, Do Thi; Dinh, Ngo Xuan; Hung, Nguyen Duy; Lan, Hoang [Department of Nanoscience and Nanotechnology, Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (HUST), No. 1 Dai Co Viet Street, Hai Ba Trung District, Hanoi (Viet Nam); Tuan, Pham Anh [Vietnam Metrology Institute, 08 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Thang, Le Hong [School of Materials Science and Engineering, Hanoi University of Science and Technology (HUST), 01 Dai Co Viet Street, Hai Ba Trung District, Hanoi (Viet Nam); Trung, Nguyen Ngoc [School of Engineering Physics, Hanoi University of Science and Technology (HUST), 01 Dai Co Viet Street, Hai Ba Trung District, Hanoi (Viet Nam); Hoa, Nguyen Quang [Department of Physics, Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Huy, Tran Quang [Laboratory for Ultrastructure and Bionanotechnology (LUBN), National Institute of Hygiene and Epidemiology (NIHE), No. 1 Yecxanh Street, Hai Ba Trung District, Hanoi (Viet Nam); Quy, Nguyen Van [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), 01 Dai Co Viet Street, Hai Ba Trung District, Hanoi (Viet Nam); Duong, Thanh-Tung [Department of Materials Engineering, Chungnam National University, Daeduk Science Town, 305-764 Daejeon (Korea, Republic of); Phan, Vu Ngoc [Department of Nanoscience and Nanotechnology, Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (HUST), No. 1 Dai Co Viet Street, Hai Ba Trung District, Hanoi (Viet Nam); Le, Anh-Tuan, E-mail: tuan.leanh1@hust.edu.vn [Department of Nanoscience and Nanotechnology, Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (HUST), No. 1 Dai Co Viet Street, Hai Ba Trung District, Hanoi (Viet Nam)

2014-12-05

Highlights: • A photochemical method for effective decoration of the Ag-NPs on GO nanosheets is presented. • The average size of the Ag-NPs on the GO nanosheets obtained ∼6–7 nm with uniform size distribution. • Surface interaction of Ag-NPs with GO nanosheets leads to surface plasmon-enhanced luminescence. - Abstract: Nanohybrid materials based on silver nanoparticles (Ag-NPs) and graphene oxide (GO) are attracting considerable research interest because of their potential many applications including surface-enhanced Raman scattering, catalysis, sensors, biomedicine and antimicrobials. In this study, we established a simple and effective method of preparing a finely dispersed Ag-GO aqueous solution using modified Hummer and photochemical technique. The Ag-NPs formation on GO nanosheets was analyzed by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The average size of Ag-NPs on the GO nanosheets was approximately 6–7 nm with nearly uniform size distribution. The Ag-GO nanohybrid also exhibits an adsorption band at 435 nm because of the presence of Ag-NPs on the GO nanosheets. Photoluminescence emission of the Ag-GO nanohybrid was found at 400 and 530 nm, which can be attributed to the interaction between the luminescence of exploited GO nanosheets and localized surface plasmon resonance from metallic Ag-NPs. The observed excellent optical properties of the as-prepared Ag-GO nanohybrid showed a significant potential for optoelectronics applications.

Au nanoparticle-decorated silicon pyramids for plasmon-enhanced hot electron near-infrared photodetection

Science.gov (United States)

Qi, Zhiyang; Zhai, Yusheng; Wen, Long; Wang, Qilong; Chen, Qin; Iqbal, Sami; Chen, Guangdian; Xu, Ji; Tu, Yan

2017-07-01

The heterojunction between metal and silicon (Si) is an attractive route to extend the response of Si-based photodiodes into the near-infrared (NIR) region, so-called Schottky barrier diodes. Photons absorbed into a metallic nanostructure excite the surface plasmon resonances (SPRs), which can be damped non-radiatively through the creation of hot electrons. Unfortunately, the quantum efficiency of hot electron detectors remains low due to low optical absorption and poor electron injection efficiency. In this study, we propose an efficient and low-cost plasmonic hot electron NIR photodetector based on a Au nanoparticle (Au NP)-decorated Si pyramid Schottky junction. The large-area and lithography-free photodetector is realized by using an anisotropic chemical wet etching and rapid thermal annealing (RTA) of a thin Au film. We experimentally demonstrate that these hot electron detectors have broad photoresponsivity spectra in the NIR region of 1200-1475 nm, with a low dark current on the order of 10-5 A cm-2. The observed responsivities enable these devices to be competitive with other reported Si-based NIR hot electron photodetectors using perfectly periodic nanostructures. The improved performance is attributed to the pyramid surface which can enhance light trapping and the localized electric field, and the nano-sized Au NPs which are beneficial for the tunneling of hot electrons. The simple and large-area preparation processes make them suitable for large-scale thermophotovoltaic cell and low-cost NIR detection applications.

Photochemical decoration of silver nanoparticles on graphene oxide nanosheets and their optical characterization

International Nuclear Information System (INIS)

Lan, Nguyen Thi; Chi, Do Thi; Dinh, Ngo Xuan; Hung, Nguyen Duy; Lan, Hoang; Tuan, Pham Anh; Thang, Le Hong; Trung, Nguyen Ngoc; Hoa, Nguyen Quang; Huy, Tran Quang; Quy, Nguyen Van; Duong, Thanh-Tung; Phan, Vu Ngoc; Le, Anh-Tuan

2014-01-01

Highlights: • A photochemical method for effective decoration of the Ag-NPs on GO nanosheets is presented. • The average size of the Ag-NPs on the GO nanosheets obtained ∼6–7 nm with uniform size distribution. • Surface interaction of Ag-NPs with GO nanosheets leads to surface plasmon-enhanced luminescence. - Abstract: Nanohybrid materials based on silver nanoparticles (Ag-NPs) and graphene oxide (GO) are attracting considerable research interest because of their potential many applications including surface-enhanced Raman scattering, catalysis, sensors, biomedicine and antimicrobials. In this study, we established a simple and effective method of preparing a finely dispersed Ag-GO aqueous solution using modified Hummer and photochemical technique. The Ag-NPs formation on GO nanosheets was analyzed by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The average size of Ag-NPs on the GO nanosheets was approximately 6–7 nm with nearly uniform size distribution. The Ag-GO nanohybrid also exhibits an adsorption band at 435 nm because of the presence of Ag-NPs on the GO nanosheets. Photoluminescence emission of the Ag-GO nanohybrid was found at 400 and 530 nm, which can be attributed to the interaction between the luminescence of exploited GO nanosheets and localized surface plasmon resonance from metallic Ag-NPs. The observed excellent optical properties of the as-prepared Ag-GO nanohybrid showed a significant potential for optoelectronics applications

Electrospun Gelatin/β-TCP Composite Nanofibers Enhance Osteogenic Differentiation of BMSCs and In Vivo Bone Formation by Activating Ca2+-Sensing Receptor Signaling

Directory of Open Access Journals (Sweden)

Xuehui Zhang

2015-01-01

Full Text Available Calcium phosphate- (CaP- based composite scaffolds have been used extensively for the bone regeneration in bone tissue engineering. Previously, we developed a biomimetic composite nanofibrous membrane of gelatin/β-tricalcium phosphate (TCP and confirmed their biological activity in vitro and bone regeneration in vivo. However, how these composite nanofibers promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs is unknown. Here, gelatin/β-TCP composite nanofibers were fabricated by incorporating 20 wt% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite β-TCP nanofibers had a nonwoven structure with a porous network and a rough surface. Spectral analyses confirmed the presence and chemical stability of the β-TCP and gelatin components. Compared with pure gelatin nanofibers, gelatin/β-TCP composite nanofibers caused increased cell attachment, proliferation, alkaline phosphatase activity, and osteogenic gene expression in rat BMSCs. Interestingly, the expression level of the calcium-sensing receptor (CaSR was significantly higher on the composite nanofibrous scaffolds than on pure gelatin. For rat calvarial critical sized defects, more extensive osteogenesis and neovascularization occurred in the composite scaffolds group compared with the gelatin group. Thus, gelatin/β-TCP composite scaffolds promote osteogenic differentiation of BMSCs in vitro and bone regeneration in vivo by activating Ca2+-sensing receptor signaling.

The Janus effect on superhydrophilic Cu mesh decorated with Ni-NiO/Ni(OH)2 core-shell nanoparticles for oil/water separation

Science.gov (United States)

Luo, Zhi-Yong; Lyu, Shu-Shen; Fu, Yuan-Xiang; Heng, Yi; Mo, Dong-Chuan

2017-07-01

Janus effect has been studied for emerging materials like Janus membranes, Janus nanoparticles, etc., and the applications including fog collection, oil/water separation, CO2 removal and stabilization of multiphasic mixtures. However, the Janus effect on oil/water separation is still unclear. Herein, Janus Cu mesh decorated with Ni-NiO/Ni(OH)2 core-shell nanoparticles is synthesized via selective electrodeposition, in which we keep one side of Cu mesh (Janus A) to be superhydrophilic, while manipulate the wettability of another side (Janus B) from hydrophobic to superhydrophilic. Experimental results indicate that Cu mesh with both-side superhydrophilic shows the superior oil/water separation performance (separation efficiency >99.5%), which is mainly due to its higher water capture percentage as well as larger oil intrusion pressure. Further, we demonstrate the orientation of Janus membranes for oil/water separation, and summarize that the wettability of the upper surface plays a more important role than the lower surface to achieve remarkable performance. Our work provides a clear insight of Janus effect on oil/water separation, it is significative to design high-performance membranes for oil/water separation and many other applications.

Kinetic study on bonding reaction of gelatin with CdS nanopaticles by UV-visible spectroscopy.

Science.gov (United States)

Tang, Shihua; Wang, Baiyang; Li, Youqun

2015-04-15

The chemical kinetics on gelatin-CdS direct conjugates has been systematically investigated as a function of different temperature and reactant concentration (i.e. Cd(2+), S(2-) and gelatin) by UV-visible spectroscopy, for the first time. The nonlinear fitting and the differential method were used to calculate the initial rate based on the absorbance-time data. A double logarithmic linear equation for calculating the rate constant (k) and the reaction order (n) was introduced. The reaction kinetic parameters (n, k, Ea, and Z) and activation thermodynamic parameters (ΔG(≠), ΔH(≠), and ΔS(≠)) were obtained from variable temperature kinetic studies. The overall rate equation allowing evaluation of conditions that provide required reaction rate could be expressed as: r = 1.11 × 10(8) exp(-4971/T)[Cd(2+)][gelatin](0.6)[S(2-)](0.6) (M/S) The calculated values of the reaction rate are well coincide with the experimental results. A suitable kinetic model is also proposed. This work will provide guidance for the rational design of gelatin-directed syntheses of metal sulfide materials, and help to understand the biological effects of nanoparticles at the molecular level. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermodynamic analysis of high-temperature regenerative organic Rankine cycles using siloxanes as working fluids

International Nuclear Information System (INIS)

Fernandez, F.J.; Prieto, M.M.; Suarez, I.

2011-01-01

A recent novel adjustment of the Span-Wagner equation of state for siloxanes, used as working fluids in high-temperature organic Rankine cycles, is applied in a mathematical model to solve cycles under several working conditions. The proposed scheme includes a thermo-oil intermediate heat circuit between the heat source and the organic Rankine cycle. Linear and cyclic siloxanes are assayed in saturated, superheated and supercritical cycles. The cycle includes an internal heat exchanger (regenerative cycle), although a non-regenerative scheme is also solved. In the first part of the study, a current of combustion gases cooled to close to their dew point temperature is taken as the reference heat source. In the second part, the outlet temperature of the heat source is varied over a wide range, determining appropriate fluids and schemes for each thermal level. Simple linear (MM, MDM) siloxanes in saturated regenerative schemes show good efficiencies and ensure thermal stability of the working fluid. -- Highlights: → Organic Rankine cycles with polymethylsiloxanes as working fluids were modelled. → The cycle scheme is regenerative and includes an intermediate heat transfer fluid. → The fluid properties were calculated by means of the Span-Wagner equation of state. → Vapour conditions to the expander and source thermal level were analysed. → Siloxanes MM, MDM and D 4 under saturated conditions were the best options.

Clinical Fit of Partial Removable Dental Prostheses Based on Alginate or Polyvinyl Siloxane Impressions.

Science.gov (United States)

Fokkinga, Wietske A; Witter, Dick J; Bronkhorst, Ewald M; Creugers, Nico H

The aim of this study was to analyze the clinical fit of metal-frame partial removable dental prostheses (PRDPs) based on custom trays used with alginate or polyvinyl siloxane impression material. Fifth-year students of the Nijmegen Dental School made 25 correct impressions for 23 PRDPs for 21 patients using alginate, and 31 correct impressions for 30 PRDPs for 28 patients using polyvinyl siloxane. Clinical fit of the framework as a whole and of each retainer separately were evaluated by calibrated supervisors during framework try-in before (first evaluation) and after (second evaluation) possible adjustments (score 0 = poor fit, up to score 3 = good fit). Framework fit and fit of the denture base were evaluated at delivery (third evaluation). Finally, postinsertion sessions were evaluated and total number of sessions needed, sore spots, adjustments to the denture base, and reported food-impaction were recorded. No significant differences in clinical fit (of the framework as a whole, for the retainers, or for the denture base) were found between the groups in the three evaluation sessions. Differences were not found for postinsertion sessions with one exception: in the alginate group, four subjects reported food impaction, versus none in the polyvinyl siloxane group. Clinical fit of metal-frame PRDPs based on impressions with custom trays combined with alginate or polyvinyl siloxane was similar.

Photoinduced Glycerol Oxidation over Plasmonic Au and AuM (M = Pt, Pd and Bi) Nanoparticle-Decorated TiO2 Photocatalysts

Science.gov (United States)

Jedsukontorn, Trin; Saito, Nagahiro; Hunsom, Mali

2018-01-01

In this study, sol-immobilization was used to prepare gold nanoparticle (Au NP)-decorated titanium dioxide (TiO2) photocatalysts at different Au weight % (wt. %) loading (Aux/TiO2, where x is the Au wt. %) and Au–M NP-decorated TiO2 photocatalysts (Au3M3/TiO2), where M is bismuth (Bi), platinum (Pt) or palladium (Pd) at 3 wt. %. The Aux/TiO2 photocatalysts exhibited a stronger visible light absorption than the parent TiO2 due to the localized surface plasmon resonance effect. Increasing the Au content from 1 wt. % to 7 wt. % led to increased visible light absorption due to the increasing presence of defective structures that were capable of enhancing the photocatalytic activity of the as-prepared catalyst. The addition of Pt and Pd coupled with the Au3/TiO2 to form Au3M3/TiO2 improved the photocatalytic activity of the Au3/TiO2 photocatalyst by maximizing their light-absorption property. The Au3/TiO2, Au3Pt3/TiO2 and Au3Pd3/TiO2 photocatalysts promoted the formation of glyceraldehyde from glycerol as the principle product, while Au3Bi3/TiO2 facilitated glycolaldehyde formation as the major product. Among all the prepared photocatalysts, Au3Pd3/TiO2 exhibited the highest photocatalytic activity with a 98.75% glycerol conversion at 24 h of reaction time. PMID:29690645

Detection of Aeromonas hydrophila DNA oligonucleotide sequence using a biosensor design based on Ceria nanoparticles decorated reduced graphene oxide and Fast Fourier transform square wave voltammetry

International Nuclear Information System (INIS)

Jafari, Safiye; Faridbod, Farnoush; Norouzi, Parviz; Dezfuli, Amin Shiralizadeh; Ajloo, Davood; Mohammadipanah, Fatemeh; Ganjali, Mohammad Reza

2015-01-01

A new strategy was introduced for ssDNA immobilization on a modified glassy carbon electrode. The electrode surface was modified using polyaniline and chemically reduced graphene oxide decorated cerium oxide nanoparticles (CeO_2NPs-RGO). A single-stranded DNA (ssDNA) probe was immobilized on the modified electrode surface. Fast Fourier transform square wave voltammetry (FFT-SWV) was applied as detection technique and [Ru(bpy)_3]"2"+"/"3"+ redox signal was used as electrochemical marker. The hybridization of ssDNA with its complementary target caused a dramatic decrease in [Ru(bpy)_3]"2"+"/"3"+ FFT-SW signal. The proposed electrochemical biosensor was able to detect Aeromonas hydrophila DNA oligonucleotide sequence encoding aerolysin protein. Under optimal conditions, the biosensor showed excellent selectivity toward complementary sequence in comparison with noncomplementary and two-base mismatch sequences. The dynamic linear range of this electrochemical DNA biosensor for detecting 20-mer oligonucleotide sequence of A. hydrophila was from 1 × 10"−"1"5 to 1 × 10"−"8 mol L"−"1. The proposed biosensor was successfully applied for the detection of DNA extracted from A. hydrophila in fish pond water up to 0.01 μg mL"−"1 with RSD of 5%. Besides, molecular docking was applied to consider the [Ru(bpy)_3]"2"+"/"3"+ interaction with ssDNA before and after hybridization. - Highlights: • New DNA biosensor is designed for sub-femtomolar detection of Aeromonas hydrophila DNA sequence. • Reduced graphene oxide decorated Ceria nanoparticles was used as a new immobilization platform. • Biosensor was successfully used to detect A. hydrophila DNA sequence in fish pond water.

Enhanced Wound Healing Using Topically Administered Nanoparticle Encapsulated siRNA

Science.gov (United States)

2013-11-01

as guar or xanthan gum , inorganic gelatinizing agents, such as aluminum hydroxide or bentonites (termed thixotropic gel-formers), polyacrylic acid...agent for preparing a suitable base, or cellulose derivatives, such as guar or xanthan gum , inorganic gelatinizing agents, such as aluminum hydroxide...coconut oil; ii) preparation of a fine powder version of the coconut oil plus nanoparticles that melts on contact with living tissue; iii

Tailoring mechanical and antibacterial properties of chitosan/gelatin nanofiber membranes with Fe{sub 3}O{sub 4} nanoparticles for potential wound dressing application

Energy Technology Data Exchange (ETDEWEB)

Cai, Ning; Li, Chao; Han, Chao; Luo, Xiaogang [Key Laboratory for Green Chemical Process of Ministry of Education & Hubei Key Laboratory of Novel Reactor & Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073 (China); Shen, Liang [Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Xue, Yanan [Key Laboratory for Green Chemical Process of Ministry of Education & Hubei Key Laboratory of Novel Reactor & Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073 (China); Yu, Faquan, E-mail: fyuwucn@gmail.com [Key Laboratory for Green Chemical Process of Ministry of Education & Hubei Key Laboratory of Novel Reactor & Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073 (China)

2016-04-30

Graphical abstract: - Highlights: • Fe{sub 3}O{sub 4} nanoparticles/chitosan (CS)/gelatin (GE) nanofibers were electrospun facilely. • Introducing Fe{sub 3}O{sub 4} enhanced mechanical and antibacterial properties of CS/GE nanofibers. • Mechanical enhancement relied on good filler dispersion and filler-matrix adhesion. • Fe{sub 3}O{sub 4}/CS/GE nanofiber membranes are promising candidates as wound dressings. - Abstract: In this work, magnetic Fe{sub 3}O{sub 4} nanoparticles (NPs) were utilized to improve the mechanical and antibacterial properties of chitosan (CS)/gelatin (GE) composite nanofiber membranes. Homogeneous Fe{sub 3}O{sub 4}/CS/GE nanofibers were electrospun successfully. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirmed the presence of well-dispersed Fe{sub 3}O{sub 4} NPs in the composite nanofibers. Fourier transform infrared spectroscopy (FTIR) spectra revealed the effective interactions of Fe{sub 3}O{sub 4} NPs to the composite matrix through hydrogen bonding. The improvement on the thermal stability of the Fe{sub 3}O{sub 4}/CS/GE was observed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA), which is tightly correlated to strong filler-matrix adhesion. The incorporation of Fe{sub 3}O{sub 4} NPs resulted in a substantial enhancement of mechanical properties. The optimum mechanical performance was demonstrated on 1 wt% Fe{sub 3}O{sub 4}/CS/GE nanofiber membranes, achieving 155% augment of Young's modulus, 128% increase of tensile strength, and 100% boost of toughness from CS/GE. The excellent mechanical enhancement can be explained by the effective dispersion of fillers and the filler-matrix interactions, which ensures the efficient load transfer from CS/GE matrix to Fe{sub 3}O{sub 4} nanofillers. Moreover, zones of inhibition for Escherichia coli and Staphylococcus aureus expanded markedly with the supplement of Fe{sub 3}O{sub 4} NPs. In all, nanofiber

Rationalizing the Permissibility of Mosque Decoration

Directory of Open Access Journals (Sweden)

Spahic Omer

2016-06-01

Full Text Available This paper discusses the subject of mosque decoration and some of the criteria which determine its permissibility or otherwise. Some aspects of the matter are somewhat sensitive and double-edged. Thus, the paper presents an objective, balanced and scientific account of the theme, steering clear of the sentimental aspects of the evidences often put forth by both the proponents and opponents of mosque decoration. The main thrusts of the paper are the issues pertaining to the legitimacy of decoration in general, the subject of the function of mosques vis-à-vis their decoration, as well as the broad guidelines that regulate mosque decoration emphasizing the decoration of the mihrab (praying niche area and the qiblah wall. The paper concludes that in principle mosque decoration is permissible so long as it conforms to the requirements of the Islamic spirituality and the quintessence of genuine Islamic art and architecture.

Halal authenticity of gelatin using species-specific PCR.

Science.gov (United States)

Shabani, Hessam; Mehdizadeh, Mehrangiz; Mousavi, Seyed Mohammad; Dezfouli, Ehsan Ansari; Solgi, Tara; Khodaverdi, Mahdi; Rabiei, Maryam; Rastegar, Hossein; Alebouyeh, Mahmoud

2015-10-01

Consumption of food products derived from porcine sources is strictly prohibited in Islam. Gelatin, mostly derived from bovine and porcine sources, has many applications in the food and pharmaceutical industries. To ensure that food products comply with halal regulations, development of valid and reliable analytical methods is very much required. In this study, a species-specific polymerase chain reaction (PCR) assay using conserved regions of mitochondrial DNA (cytochrome b gene) was performed to evaluate the halal authenticity of gelatin. After isolation of DNA from gelatin powders with known origin, conventional PCR using species-specific primers was carried out on the extracted DNA. The amplified expected PCR products of 212 and 271 bp were observed for porcine and bovine gelatin, respectively. The sensitivity of the method was tested on binary gelatin mixtures containing 0.1%, 1%, 10%, and 100% (w/w) of porcine gelatin within bovine gelatin and vice versa. Although most of the DNA is degraded due to the severe processing steps of gelatin production, the minimum level of 0.1% w/w of both porcine and bovine gelatin was detected. Moreover, eight food products labeled as containing bovine gelatin and eight capsule shells were subjected to PCR examination. The results showed that all samples contained bovine gelatin, and the absence of porcine gelatin was verified. This method of species authenticity is very useful to verify whether gelatin and gelatin-containing food products are derived from halal ingredients. Copyright © 2015 Elsevier Ltd. All rights reserved.

HDPE/clay hybrids: the effect of clay modified with poly(diphenyl siloxanes) on thermal and rheological properties

Energy Technology Data Exchange (ETDEWEB)

Monasterio, Fernanda E.; Carrera, Maria C.; Erdmann, Eleonora; Destefanis, Hugo A., E-mail: ferelenakq@gmail.co [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina). Inst. de Investigaciones para la Industria Quimica; Pita, Victor J.R.R.; Dias, Marcos L. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

2009-07-01

Poly(diphenyl siloxanes) (PDPhS) were synthesized in presence of organophilic clay in order to modify its nano structure. Two silane monomers were used: dimethoxydiphenylsilane and dichlorodiphenylsilane. The following characterizations were performed for all clays: XRD, FTIR and TGA/DTG. These siloxane-modified clays were more hydrophobic and had enhanced thermal stability. Solvent extraction was carried out in the siloxane-modified clays and the PDPhS soluble fraction analyzed according the molecular weight via GPC. The presence of free and grafted oligomers on clay surface was identified. The modified clays were added to HDPE by melt processing to obtain HDPE/clay hybrids which exhibited marked differences in the rheological behavior when compared with neat HDPE. (author)

HDPE/clay hybrids: the effect of clay modified with poly(diphenyl siloxanes) on thermal and rheological properties

International Nuclear Information System (INIS)

Monasterio, Fernanda E.; Carrera, Maria C.; Erdmann, Eleonora; Destefanis, Hugo A.; Pita, Victor J.R.R.; Dias, Marcos L.

2009-01-01

Poly(diphenyl siloxanes) (PDPhS) were synthesized in presence of organophilic clay in order to modify its nano structure. Two silane monomers were used: dimethoxydiphenylsilane and dichlorodiphenylsilane. The following characterizations were performed for all clays: XRD, FTIR and TGA/DTG. These siloxane-modified clays were more hydrophobic and had enhanced thermal stability. Solvent extraction was carried out in the siloxane-modified clays and the PDPhS soluble fraction analyzed according the molecular weight via GPC. The presence of free and grafted oligomers on clay surface was identified. The modified clays were added to HDPE by melt processing to obtain HDPE/clay hybrids which exhibited marked differences in the rheological behavior when compared with neat HDPE. (author)

Palladium nanoparticles anchored on graphene nanosheets: Methanol, ethanol oxidation reactions and their kinetic studies

KAUST Repository

Nagaraju, Doddahalli H.

2014-12-01

Palladium nanoparticles decorated graphene (Gra/Pd nanocomposite) was synthesized by simultaneous chemical reduction of graphene oxide and palladium salt in a single step. The negatively charged graphene oxide (GO) facilitates uniform distribution of Pd2+ ions onto its surface. The subsequent reduction by hydrazine hydrate provides well dispersed Pd nanoparticles decorated graphene. Different amount of Pd nanoparticles on graphene was synthesized by changing the volume to weight ratio of GO to PdCl2. X-ray diffraction studies showed FCC lattice of Pd with predominant (1 1 1) plane. SEM and TEM studies revealed that thin graphene nanosheets are decorated by Pd nanoparticles. Raman spectroscopic studies revealed the presence of graphene nanosheets. The electro-catalytic activity of Gra/Pd nanocomposites toward methanol and ethanol oxidation in alkaline medium was evaluated by cyclic voltammetric studies. 1:1 Gra/Pd nanocomposite exhibited good electro-catalytic activity and efficient electron transfer. The kinetics of electron transfer was studied using chronoamperometry. Improved electro-catalytic activity of 1:1 Gra/Pd nanocomposite toward alcohol oxidation makes it as a potential anode for the alcohol fuel cells. © 2014 Elsevier Ltd.

Dielectric constant and refractive index of poly (siloxane-imide) block copolymer

International Nuclear Information System (INIS)

Othman, Muhammad Bisyrul Hafi; Ramli, Mohamad Riduwan; Tyng, Looi Yien; Ahmad, Zulkifli; Akil, Hazizan Md.

2011-01-01

Highlights: → We synthesis a series of poly(siloxane-imide) block copolymer. → We deals and examine the changes in optoelectronic properties. → The increasing silicone unit, decrease refractive index and dielectric properties. → However it does not significantly affected the optical transparency. -- Abstract: Recent technological advances demanded polyimides of improved versatility in terms of electronic, optical and thermal properties. In this work, a series of poly(siloxane-imide) block copolymers were synthesized in order to investigate the effect on their optical and electronic properties. The polyimide unit was derived from 3,3',4,4'-Biphenyltetracarboxylic dianhydride (BPDA) and 4-(4-{1-[4-(4-aminophenoxy) phenyl]-1-methylethyl} phenoxy) aniline (BAPP) while the siloxane unit was derived from 3-[3-(3-aminopropyl)-1,1,3,3-tetramethyldisiloxanyl] propylamine (DMS) and Poly(dimethylsiloxane), bis(3-aminopropyl)terminated (PDMS). The structure of the polyimide was characterized by fourier transformer infra red (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, solution viscosity and gas permeation chromatography (GPC). Scanning electron microscope (SEM) analysis suggested a microphase separation between the two components. The refractive index and dielectric properties showed a decreasing trend with increased silicone unit in the polyimide backbone. However ultra violet visible (UV-Vis) and optical transparency was not significantly affected. Electronic and optical properties of this copolymer were discussed in relation to the polysiloxane content.

Ethanol sensing properties and dominant sensing mechanism of NiO-decorated SnO2 nanorod sensors

Science.gov (United States)

Sun, Gun-Joo; Lee, Jae Kyung; Lee, Wan In; Dwivedi, Ram Prakash; Lee, Chongmu; Ko, Taegyung

2017-05-01

NiO-decorated SnO2 nanorods were synthesized by the thermal evaporation of Sn powders followed by the solvothermal deposition of NiO. A multi-networked p- n heterostructured nanorod sensor was fabricated by dropping the p-NiO-decorated n-SnO2 nanorods onto the interdigited electrode pattern and then annealing. The multi-networked p- n heterostructured nanorod sensor exhibited enhanced response to ethanol compared with the pristine SnO2 nanorod and NiO nanoparticle sensors. The former also exhibited a shorter sensing time for ethanol. Both sensors exhibited selectivity for ethanol over other volatile organic compounds (VOCs) such as HCHO, methanol, benzene and toluene and the decorated sensor exhibited superior selectivity to the other two sensors. In addition, the dominant sensing mechanism is discussed in detail by comparing the sensing properties and current-voltage characteristics of a p-NiO/ n-SnO2 heterostructured nanorod sensor with those of a pristine SnO2 nanorod sensor and a pristine NiO nanoparticle sensor. Of the two competing electronic mechanisms: a potential barrier-controlled carrier transport mechanism at a NiO-SnO2 p- n junction and a surface-depletio n-controlled carrier transport mechanism, the former has some contribution to the enhanced gas sensing performance of the p- n heterostructured nanorod sensor, however, its contribution is not as significant as that of the latter. [Figure not available: see fulltext.

Isoniazid loaded gelatin-cellulose whiskers nanoparticles for ...

Indian Academy of Sciences (India)

Controlled drug delivery system represents one of the most advancing areas .... was added drop by drop as cross-linker to crosslink the nanoparticles. ... The distribution of isoni- ... (JEOL JSM – 6390LV) with an acceleration voltage of. 15 kV.

Preparation of Rare Earth Doped Alumina-Siloxane Gel and Its ER Effect

Institute of Scientific and Technical Information of China (English)

李幼荣; 张明; 周兰香; 邱关明; 井上真一; 冈本宏

2002-01-01

Poly(methyl methacrylate) (PMMA) was used to wrap alumina-siloxane sol through emulsion polymerization. A kind of suspensions with notable ER effect was produced by fully mixing the prepared microcapsule with silicon oil. Meanwhile a series of PMMA wrapped alumina-siloxane gel doped with rare earths was obtained and its ER effect was tested, like viscosity of different rare earth ion doped samples in different powder concentrations and at different temperatures, at the same time, leak current density and dielectric constant were measured. Results show that the ER effect of this suspension is remarkable, and its stability is much better. The condition of emulsion polymerization and the mechanism of effect are discussed.

Fabrication a new modified electrochemical sensor based on Au–Pd bimetallic nanoparticle decorated graphene for citalopram determination

Energy Technology Data Exchange (ETDEWEB)

Daneshvar, Leili [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Rounaghi, Gholam Hossein, E-mail: ghrounaghi@yahoo.com [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Es' haghi, Zarrin [Department of Chemistry, Faculty of Sciences, Payame Noor University, Mashhad (Iran, Islamic Republic of); Chamsaz, Mahmoud; Tarahomi, Somayeh [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

2016-12-01

This paper proposes a simple approach for sensing of citalopram (CTL) using gold–palladium bimetallic nanoparticles (Au–PdNPs) decorated graphene modified gold electrode. Au–PdNPs were deposited at the surface of a graphene modified gold electrode with simple electrodeposition method. The morphology and the electrochemical properties of the modified electrode were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersion spectroscopy (EDS), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and square wave voltammetry (SWV). The novel sensor exhibited an excellent catalytic activity towards the oxidation of CTL. The oxidation peak current of CTL, was linear in the range of 0.5–50 μM with a detection limit 0.049 μM with respect to concentration of citalopram. The proposed sensor was successfully applied for determination of CTL tablet and human plasma samples with satisfactory results. - Highlights: • A novel sensor based on Au-PdNPs deposited graphene modified gold electrode was fabricated. • The morphology and the electrochemical properties of the sensor were characterized by several methods. • The fabricated sensor was employed for the detection of antidepressant drug CTL with satisfactory results.

Detection of porcine DNA in gelatine and gelatine-containing processed food products-Halal/Kosher authentication.

Science.gov (United States)

Demirhan, Yasemin; Ulca, Pelin; Senyuva, Hamide Z

2012-03-01

A commercially available real-time PCR, based on a multi-copy target cytochrome b (cyt b) using porcine specific primers, has been validated for the Halal/Kosher authentication of gelatine. Extraction and purification of DNA from gelatine were successfully achieved using the SureFood® PREP Animal system, and real-time PCR was carried out using SureFood® Animal ID Pork Sens kit. The minimum level of adulteration that could be detected was 1.0% w/w for marshmallows and gum drops. A small survey was undertaken of processed food products such as gum drops, marshmallows and Turkish delight, believed to contain gelatine. Of fourteen food products from Germany, two samples were found to contain porcine gelatine, whereas of twenty-nine samples from Turkey twenty-eight were negative. However, one product from Turkey contained porcine DNA and thus was not Halal, and neither was the use of porcine gelatine indicated on the product label. Copyright © 2011 Elsevier Ltd. All rights reserved.

Ag-decorated Fe_3O_4@SiO_2 core-shell nanospheres: Seed-mediated growth preparation and their antibacterial activity during the consecutive recycling

International Nuclear Information System (INIS)

Li, Miaomiao; Wu, Wenjie; Qiao, Ru; Tan, Linxiang; Li, Zhengquan; Zhang, Yong

2016-01-01

We demonstrated a seed-mediated growth approach to synthesize Ag nanoparticles-decorated Fe_3O_4@SiO_2 core-shell nanospheres without use of surface functionalization. The particle size and decoration density of the immobilized Ag nanoparticles on SiO_2 surface were tunable by adjusting the added AgNO_3 concentration and the alternating repetition times in seed-mediated growth procedure. The as-prepared Ag-decorated Fe_3O_4@SiO_2 nanospheres exhibited excellent antibacterial activities against Escherichia coli, Bacillus subtilis and Candida albicans, in which the minimum inhibitory concentration were 12.5 μg mL"−"1, 50 μg mL"−"1 and 50 μg mL"−"1, respectively. It is speculated that their antibacterial activity is attributed to both the interaction of released Ag ions with the functional groups of vital enzymes and proteins and the strong oxidation of reactive oxygen species generated under the action of photoinduced electrons in Ag nanoparticles. Besides studying their antibacterial mechanism, we also investigated the variation of antibacterial activity of these heterostructured nanospheres during the consecutive magnetic separation and recycling. It shows that the magnetic antibacterial agent could be reused and its activity remained stable even after nine cycles, which enable it to be promisingly applied in biomedical areas. - Highlights: • Ag-decorated Fe_3O_4@SiO_2 were synthesized via a seed-mediated growth method. • The core-shell heterostructures exhibited excellent antibacterial activity. • The activity was attributed to the effect of released Ag"+ with ROS oxidation. • The antibacterial agent was reused during magnetic separation and recycling.

The Use of Decorative Styles of Woven Songket as a Source of Learning in the Course Textile Design and Decoration

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Made Budhyani I Dewa Ayu

2018-01-01

Full Text Available The use of learning sources in the learning process greatly contributes to the achievement of its goal. The use of learning sources greatly affects the teaching and learning process. It is necessary to use different learning sources when creating a textile design in order to produce a quality product. The decorative style of woven songket can be used as one of the learning sources. The different decorative types of the woven songket contain aesthetic values. The decorative type of woven songket is a product of the crafter’s feeling, creativity, and intention inspired by the environment. The natural objects such as plants, animals, human beings, and geometric elements are stylized into the decorative forms. The decorative style used on the woven songket can be used as the learning source in order to create the decorative style in the course Textile Design and Decoration. There are several aesthetic elements which inspire where the decorative style is placed; they are composition, rhythm, balance, the harmonious layout of the decorative style, and the variation of the decorative style on the textile design. In general, the composition of the placement of the main object of the decorative style is more dominant on the piece of fabric. Rhythm and how the decorative style is composed are shown through the composition of the decorative motive forms such as how big and small they are, how high and low they are and how long and short they are. The ways in which the decorative motives and colors are entirely shown contribute to the harmony and placement of decorative style. The symmetric balance is used to create balance and avoid the impression of being biased. The placement of what the motives contain and how they are composed are used to determine the variation of the decorative style used. The placement of objects and the marginal decoration of the fabric also determine the variation used.

Hierarchical Bi{sub 2}WO{sub 6} architectures decorated with Pd nanoparticles for enhanced visible-light-driven photocatalytic activities

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jinniu; Chen, Tianhua [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Lu, Hongbing, E-mail: hblu@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Yang, Zhibo; Yin, Feng; Gao, Jianzhi; Liu, Qianru [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Tu, Yafang [Department of Physics, Institute for Interdisciplinary Research, Jianghan University, Wuhan, 430056 (China)

2017-05-15

Highlights: • A new kind of Pd decorated Bi{sub 2}WO{sub 6} hierarchical microarchitecture was synthesized. • Pd nanoparticles remarkably improved the photocatalytic activity of Bi{sub 2}WO{sub 6}. • The photo-generated holes and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. • The photocatalytic enhancement mechanism of the Pd-Bi{sub 2}WO{sub 6} composites was proposed. - Abstract: A new kind of hierarchical Pd-Bi{sub 2}WO{sub 6} architecture decorated with different molar ratios of Pd to Bi, has been fabricated by a hydrothermal process, followed by a chemical deposition method. The photocatalytic activities of the pure Bi{sub 2}WO{sub 6} and Pd-Bi{sub 2}WO{sub 6} nanocatalyst were examined in the degradation of Rhodamine B (RhB) dyes and phenol under visible light. The photocatalytic results showed that the Pd-Bi{sub 2}WO{sub 6} nanocomposites possessed observably enhanced photocatalytic activities. Particularly, the 2.0% Pd loaded Bi{sub 2}WO{sub 6} had the highest photocatalytic activity, exhibiting a nearly complete degradation of 30 mg/L RhB and 10 mg/L phenol within only 50 and 60 min, respectively. In addition, the trapping experiment results indicated that the photo-generated holes (h{sup +}) and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. According to the experimental results, the photocatalytic degradation mechanism of Pd-Bi{sub 2}WO{sub 6} was also proposed. The enhanced photocatalytic activities were ascribed to the combined effects of the highly efficient separation of electrons and holes, improved visible light utilization and increased BET specific surface areas of the Pd-Bi{sub 2}WO{sub 6} nanocomposites.

Three-dimensional mapping of fluorescent nanoparticles using incoherent digital holography.

Science.gov (United States)

Yanagawa, Takumi; Abe, Ryosuke; Hayasaki, Yoshio

2015-07-15

Three-dimensional mapping of fluorescent nanoparticles was performed by using incoherent digital holography. The positions of the nanoparticles were quantitatively determined by using Gaussian fitting of the axial- and lateral-diffraction distributions through position calibration from the observation space to the sample space. It was found that the axial magnification was constant whereas the lateral magnification linearly depended on the axial position of the fluorescent nanoparticles. The mapping of multiple fluorescent nanoparticles fixed in gelatin and a single fluorescent nanoparticle manipulated with optical tweezers in water were demonstrated.

Jomon pottery: cord-imitating decoration

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Irina Zhushchikhovskaya

2007-12-01

Full Text Available The paper discusses the decoration of pottery of the Neolithic Jomon culture (Japanese Archipelago, 13600–900 BC. The comb-impressed pattern produced by various kinds of cord or rope stamps is considered as the ‘calling card’ of Jomon pottery from the earliest cultural periods to the latest. Another kind of decoration recognized recently uses the cord not as a patterning tool, but as an essential motif of decorative composition. High relief elements imitate cordage forms and structures – knots, loops, hanging cord, net, etc. This kind of decoration corresponds to the pottery of Mid-dle Jomon period (3500–2500 BC sites located in northern and north-eastern Honshu and southern Hokkaido. It is supposed that the introduction of images of real material object into the field of decorative art was reasoned by the meaning of cord and cordage as cultural signs during the Middle Jomon period. Interesting parallels to some cordage structures reconstructed on Middle Jomon pottery decoration are well known in traditional Japanese culture of VI–XX cc. Analytical interpretation of this resemblance may became the subject of special research.

Detection of Aeromonas hydrophila DNA oligonucleotide sequence using a biosensor design based on Ceria nanoparticles decorated reduced graphene oxide and Fast Fourier transform square wave voltammetry

Energy Technology Data Exchange (ETDEWEB)

Jafari, Safiye [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Faridbod, Farnoush, E-mail: faridbodf@khayam.ut.ac.ir [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Norouzi, Parviz [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Dezfuli, Amin Shiralizadeh [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ajloo, Davood [School of Chemistry, Damghan University, Damghan (Iran, Islamic Republic of); Mohammadipanah, Fatemeh [Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, 14155-6455 Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2015-10-01

A new strategy was introduced for ssDNA immobilization on a modified glassy carbon electrode. The electrode surface was modified using polyaniline and chemically reduced graphene oxide decorated cerium oxide nanoparticles (CeO{sub 2}NPs-RGO). A single-stranded DNA (ssDNA) probe was immobilized on the modified electrode surface. Fast Fourier transform square wave voltammetry (FFT-SWV) was applied as detection technique and [Ru(bpy){sub 3}]{sup 2+/3+} redox signal was used as electrochemical marker. The hybridization of ssDNA with its complementary target caused a dramatic decrease in [Ru(bpy){sub 3}]{sup 2+/3+} FFT-SW signal. The proposed electrochemical biosensor was able to detect Aeromonas hydrophila DNA oligonucleotide sequence encoding aerolysin protein. Under optimal conditions, the biosensor showed excellent selectivity toward complementary sequence in comparison with noncomplementary and two-base mismatch sequences. The dynamic linear range of this electrochemical DNA biosensor for detecting 20-mer oligonucleotide sequence of A. hydrophila was from 1 × 10{sup −15} to 1 × 10{sup −8} mol L{sup −1}. The proposed biosensor was successfully applied for the detection of DNA extracted from A. hydrophila in fish pond water up to 0.01 μg mL{sup −1} with RSD of 5%. Besides, molecular docking was applied to consider the [Ru(bpy){sub 3}]{sup 2+/3+} interaction with ssDNA before and after hybridization. - Highlights: • New DNA biosensor is designed for sub-femtomolar detection of Aeromonas hydrophila DNA sequence. • Reduced graphene oxide decorated Ceria nanoparticles was used as a new immobilization platform. • Biosensor was successfully used to detect A. hydrophila DNA sequence in fish pond water.

Synthesis of a novel Au nanoparticles decorated Ni-MOF/Ni/NiO nanocomposite and electrocatalytic performance for the detection of glucose in human serum.

Science.gov (United States)

Chen, Jingyuan; Xu, Qin; Shu, Yun; Hu, Xiaoya

2018-07-01

A nonenzymatic glucose electrochemical sensor was constructed based on Au nanoparticles (AuNPs) decorated Ni metal-organic-framework (MOF)/Ni/NiO nanocomposite. Ni-MOF/Ni/NiO nanocomposite was synthesized by one-step calcination of Ni-MOF. Then AuNPs were loaded onto the Ni-based nanocomposites' surface through electrostatic adsorption. Through characterization by transmission electron microscopy (TEM), high resolution TEM (HRTEM) and energy disperse spectroscopy (EDS) mapping, it is found that the AuNPs were well distributed on the surface of Ni-based nanocomposite. Cyclic voltammetric (CV) study showed the electrocatalytic activity of Au-Ni nanocomposite was highly improved after loading AuNPs onto it. Amperometric study demonstrated that the Au-Ni nanocomposites modified glassy carbon electrode (GCE) exhibited a high sensitivity of 2133.5 mA M -1 cm -2 and a wide linear range (0.4-900 μM) toward the oxidation of glucose with a detection limit as low as 0.1 μM. Moreover, the reproducibility, selectivity and stability of the sensor all exhibited outstanding performance. We applied the as-fabricated high performance sensor to measure the glucose levels in human serum and obtained satisfactory results. It is believed that AuNPs decorated Ni MOF/Ni/NiO nanocomposite provides a new platform for developing highly performance electrochemical sensors in practical applications. Copyright © 2018 Elsevier B.V. All rights reserved.

PdCu alloy nanoparticle-decorated copper nanotubes as enhanced electrocatalysts: DFT prediction validated by experiment

Science.gov (United States)

Wu, Dengfeng; Xu, Haoxiang; Cao, Dapeng; Fisher, Adrian; Gao, Yi; Cheng, Daojian

2016-12-01

In order to combine the advantages of both 0D and 1D nanostructured materials into a single catalyst, density functional theory (DFT) calculations have been used to study the PdCu alloy NP-decorated Cu nanotubes (PdCu@CuNTs). These present a significant improvement of the electrocatalytic activity of formic acid oxidation (FAO). Motivated by our theoretical work, we adopted the seed-mediated growth method to successfully synthesize the nanostructured PdCu@CuNTs. The new catalysts triple the catalytic activity for FAO, compared with commercial Pd/C. In summary, our work provides a new strategy for the DFT prediction and experimental synthesis of novel metal NP-decorated 1D nanostructures as electrocatalysts for fuel cells.

Differences in volatile methyl siloxane (VMS) profiles in biogas from landfills and anaerobic digesters and energetics of VMS transformations

Energy Technology Data Exchange (ETDEWEB)

Tansel, Berrin, E-mail: tanselb@fiu.edu; Surita, Sharon C.

2014-11-15

Highlights: • In the digester gas, D4 and D5 comprised the 62% and 27% if siloxanes, respectively. • In landfill gas, the bulk of siloxanes were TMSOH (58%) followed by D4 (17%). • Methane utilization may be a possible mechanism for TMSOH formation in the landfills. • The geometric configurations of D4 and D5 molecules make them very stable. - Abstract: The objectives of this study were to compare the types and levels of volatile methyl siloxanes (VMS) present in biogas generated in the anaerobic digesters and landfills, evaluate the energetics of siloxane transformations under anaerobic conditions, compare the conditions in anaerobic digesters and municipal solid waste (MSW) landfills which result in differences in siloxane compositions. Biogas samples were collected at the South District Wastewater Treatment Plant and South Dade Landfill in Miami, Florida. In the digester gas, D4 and D5 comprised the bulk of total siloxanes (62% and 27%, respectively) whereas in the landfill gas, the bulk of siloxanes were trimethylsilanol (TMSOH) (58%) followed by D4 (17%). Presence of high levels of TMSOH in the landfill gas indicates that methane utilization may be a possible reaction mechanism for TMSOH formation. The free energy change for transformation of D5 and D4 to TMSOH either by hydrogen or methane utilization are thermodynamically favorable. Either hydrogen or methane should be present at relatively high concentrations for TMSOH formation which explains the high levels present in the landfill gas. The high bond energy and bond distance of the Si–O bond, in view of the atomic sizes of Si and O atoms, indicate that Si atoms can provide a barrier, making it difficult to break the Si–O bonds especially for molecules with specific geometric configurations such as D4 and D5 where oxygen atoms are positioned inside the frame formed by the large Si atoms which are surrounded by the methyl groups.

Historical origins of Petrykivsky decorative painting

Directory of Open Access Journals (Sweden)

T. A. Harkava

2017-07-01

Full Text Available Petrykivsky decorative painting is a part of Ukrainian folk art. Domestic science of folk art has originated and has been developing primarily as a study of archaeological antiquities and artistic monuments of the past. Scientific papers, which comprehended the process of folk art development, began to appear in the late nineteenth century, Archaeological Congresses became the impetus for their appearance. Being a representative of the decorative painting, Petrikivsky decorative painting is rooted by its murals to Tripoli. It was created as a peasant domestic drawing. Inexhaustible diversity of local variants of Petrikivsky decorative painting, its evolutionary change, the individual characteristics of paintings of hundreds of famous Ukrainian artists do not even allow comparing it to any other European counterparts, each of which is characterized only by some individual techniques. Petrikivsky decorative painting got the significant boost in its distribution and development when it «came down» from walls to paper. Paper pictures - malyovky - were stucked to walls following the traditional rules of domestic interior’s decoration. Petrikivsky decorative painting got the official status in 1913, when E. Evenbah, by the initiative of D.I. Yavornytsky, gathered the collection of Petrikivsky decorative painting’s malyovkas and organized the exhibition in St. Petersburg. Motives of painting are rooted into the local flora and fauna and into the historical tradition. However, Petrikivsky decorative painting is not a direct reflection of natural motifs. World, created in paintings, is the product of the imagination of folk artist, it is the stylization of local flowers, fruits and birds. First names of Masters of Petrikivsky decorative painting, which appeared in historical sources, were T. Pata, N. Bilokin, I. Pavlenko. Their official recognition happened in 1930 after their participation in the first republican exhibition, which was later shown

Influence of liquid phase on nanoparticle-based giant electrorheological fluid.

Science.gov (United States)

Gong, Xiuqing; Wu, Jinbo; Huang, Xianxiang; Wen, Weijia; Sheng, Ping

2008-04-23

We show that the chemical structures of silicone oils can have an important role in the giant electrorheological (GER) effect. The interaction between silicone oils and solid nanoparticles is found to significantly influence the ER effect. By increasing the kinematic viscosity of silicone oils, which is a function of siloxane chain length, sol-like, gel-like and clay-like appearances of the constituted ER fluids were observed. Different functional-group-terminated silicone oils were also employed as the dispersing media. Significant differences of yield stress were found. We systematically study the effect of siloxane chain lengths on the permeability of oils traveling through the porous spaces between the particles (using the Washburn method), oils adsorbed on the particles' surface (using FT-IR spectra), as well as their particle size distribution (using dynamic light scattering). Our results indicate the hydrogen bonds are instrumental in linking the silicone oil to GER solid particles, and long chain lengths can enhance the agglomeration of the GER nanoparticles to form large clusters. An optimal oil structure, with hydroxyl-terminated silicone oil and a suitable viscosity, was chosen which can create the highest yield stress of ∼300 kPa under a 5 kV mm(-1) DC electric field.

Boron filled siloxane polymers for radiation shielding

Science.gov (United States)

Labouriau, Andrea; Robison, Tom; Shonrock, Clinton; Simmonds, Steve; Cox, Brad; Pacheco, Adam; Cady, Carl

2018-03-01

The purpose of the present work was to evaluate changes to structure-property relationships of 10B filled siloxane-based polymers when exposed to nuclear reactor radiation. Highly filled polysiloxanes were synthesized with the intent of fabricating materials that could shield high neutron fluences. The newly formulated materials consisted of cross-linked poly-diphenyl-methylsiloxane filled with natural boron and carbon nanofibers. This polymer was chosen because of its good thermal and chemical stabilities, as well as resistance to ionizing radiation thanks to the presence of aromatic groups in the siloxane backbone. Highly isotopically enriched 10B filler was used to provide an efficient neutron radiation shield, and carbon nanofibers were added to improve mechanical strength. This novel polymeric material was exposed in the Annular Core Research Reactor (ACRR) at Sandia National Labs to five different neutron/gamma fluxes consisting of very high neutron fluences within very short time periods. Thermocouples placed on the specimens recorded in-situ temperature changes during radiation exposure, which agreed well with those obtained from our MCNP simulations. Changes in the microstructural, thermal, chemical, and mechanical properties were evaluated by SEM, DSC, TGA, FT-IR NMR, solvent swelling, and uniaxial compressive load measurements. Our results demonstrate that these newly formulated materials are well-suitable to be used in applications that require exposure to different types of ionizing conditions that take place simultaneously.

Enzyme-Gelatin Electrochemical Biosensors: Scaling Down

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Hendrik A. Heering

2012-03-01

Full Text Available In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

Preparation of silica nanoparticles through microwave-assisted acid-catalysis.

Science.gov (United States)

Lovingood, Derek D; Owens, Jeffrey R; Seeber, Michael; Kornev, Konstantin G; Luzinov, Igor

2013-12-16

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan δ solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials' morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by Stöber's methods, which have smooth surfaces.

Biosynthesis and Characterization of Nanocellulose-Gelatin Films

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Muenduen Phisalaphong

2013-02-01

Full Text Available A nanocellulose-gelatin (bacterial cellulose gelatin (BCG film was developed by a supplement of gelatin, at a concentration of 1%–10% w/v, in a coconut-water medium under the static cultivation of Acetobacter xylinum. The two polymers exhibited a certain degree of miscibility. The BCG film displayed dense and uniform homogeneous structures. The Fourier transform infrared spectroscopy (FTIR results demonstrated interactions between the cellulose and gelatin. Incorporation of gelatin into a cellulose nanofiber network resulted in significantly improved optical transparency and water absorption capacity of the films. A significant drop in the mechanical strengths and a decrease in the porosity of the film were observed when the supplement of gelatin was more than 3% (w/v. The BCG films showed no cytotoxicity against Vero cells.

Instrumental texture profile analysis of gelatin gel extracted from grouper skin and commercial (bovine and porcine) gelatin gels.

Science.gov (United States)

Rahman, Mohammad Shafiur; Al-Mahrouqi, Abdullah Issa

2009-01-01

Mechanical compression was used to study the gelling characteristics of gelatin gels. Texture profile analysis (TPA) showed that the hardness of fish and mammalian gelatin increased significantly as the concentrations of gels increased. TPA attributes of 10% fish skin gel showed significant differences from those obtained from 20% and 30% gels. In bovine and porcine cases, such generic trends were not observed. Mechanical characteristics of 10% gels of gelatin from fish skin, determined from one cycle compression, were significantly lower than other sources of gelatin gels, while bovine and porcine gels did not show any significant differences. In the case of TPA, hardness of bovine gelatin gel was highest at 41 N for 10% gel, followed by porcine (30 N) then fish skin (5 N) gelatin gels. The gels prepared from different sources did not show any generic trends when all other mechanical attributes were considered.

Enzymatic degradation of polycaprolactone–gelatin blend

International Nuclear Information System (INIS)

Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar

2015-01-01

Blends of polycaprolactone (PCL), a synthetic polymer and gelatin, natural polymer offer a optimal combination of strength, water wettability and cytocompatibility for use as a resorbable biomaterial. The enzymatic degradation of PCL, gelatin and PCL–gelatin blended films was studied in the presence of lipase (Novozym 435, immobilized) and lysozyme. Novozym 435 degraded the PCL films whereas lysozyme degraded the gelatin. Though Novozym 435 and lysozyme individually could degrade PCL–gelatin blended films, the combination of these enzymes showed the highest degradation of these blended films. Moreover, the enzymatic degradation was much faster when fresh enzymes were added at regular intervals. The changes in physico-chemical properties of polymer films due to degradation were studied by scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. These results have important implications for designing resorbable biomedical implants. (paper)

Characterization of an Olive Flounder Bone Gelatin-Zinc Oxide Nanocomposite Film and Evaluation of Its Potential Application in Spinach Packaging.

Science.gov (United States)

Beak, Songee; Kim, Hyeri; Song, Kyung Bin

2017-11-01

Olive flounder bone gelatin (OBG) was used for a film base material in this study. In addition, zinc oxide nanoparticles (ZnO) were incorporated into the OBG film to prepare a nanocomposite film and to impart antimicrobial activity to it. The tensile strength of the OBG film increased by 6.62 MPa, and water vapor permeability and water solubility decreased by 0.93 × 10 -9 g/m s Pa and 13.79%, respectively, by the addition of ZnO to the OBG film. In particular, the OBG-ZnO film exhibited antimicrobial activity against Listeria monocytogenes. To investigate the applicability of the OBG-ZnO packaging film, fresh spinach was wrapped in this film and stored for a week. The results indicated that the OBG-ZnO film showed antimicrobial activity against L. monocytogenes inoculated on spinach without affecting the quality of spinach, such as vitamin C content and color. Thus, the OBG-ZnO nanocomposite film can be applied as an efficient antimicrobial food packaging material. As a base material of edible films, gelatin was extracted from olive flounder bone, which is fish processing by-product. Olive flounder bone gelatin (OBG) nanocomposite films were prepared with zinc oxide nanoparticles (ZnO). For an application to antimicrobial packaging, spinach was wrapped with the OBG-ZnO nanocomposite film. © 2017 Institute of Food Technologists®.

Enhanced photoelectrocatalytic performance for degradation of diclofenac and mechanism with TiO2 nano-particles decorated TiO2 nano-tubes arrays photoelectrode

International Nuclear Information System (INIS)

Cheng, Xiuwen; Liu, Huiling; Chen, Qinghua; Li, Junjing; Wang, Pu

2013-01-01

In this study, TiO 2 nano-particles decorated TiO 2 nano-tubes arrays (TiO 2 NPs/TiO 2 NTAs) photoelectrodes have been successfully prepared through anodization, combined with ultrasonic strategy, followed by annealing post-treatment. The morphology and structure of the as-prepared TiO 2 NPs/TiO 2 NTAs photoelectrodes were characterized by scanning electrons microscopy (SEM), N 2 adsorption/desorption isotherms, X-ray diffraction (XRD) and UV–visible light diffuse reflection spectroscopy (DRS). In addition, the generation of hydroxyl radicals (·OH) was detected by a photoluminescence (PL) spectra using terephthalic acid (TA) as a probe molecule. Furthermore, the photoelectrochemical (PECH) properties of TiO 2 NPs/TiO 2 NTAs photoanode were investigated through transient open circuit potential (OCP), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS). It was found that TiO 2 NPs/TiO 2 NTAs photoelectrode exhibited a distinct decrease of OCP of −0.219 mV cm −2 and PCR of 0.049 mA cm −2 , while a significantly enhanced photoelectrocatalytic (PEC) efficiency of 63.6% (0.4 V vs. SCE) for the degradation of diclofenac. Moreover, the enhanced PEC mechanism of TiO 2 NPs/TiO 2 NTAs photoanode was proposed. The high PEC performance could be attributed to the decoration of TiO 2 NPs, which could improve the mobility and separation efficiency of photoinduced charge carriers under external potential

Comparison of different cationized proteins as biomaterials for nanoparticle-based ocular gene delivery.

Science.gov (United States)

Zorzi, Giovanni K; Párraga, Jenny E; Seijo, Begoña; Sanchez, Alejandro

2015-11-01

Cationized polymers have been proposed as transfection agents for gene therapy. The present work aims to improve the understanding of the potential use of different cationized proteins (atelocollagen, albumin and gelatin) as nanoparticle components and to investigate the possibility of modulating the physicochemical properties of the resulting nanoparticle carriers by selecting specific protein characteristics in an attempt to improve current ocular gene-delivery approaches. The toxicity profiles, as well as internalization and transfection efficiency, of the developed nanoparticles can be modulated by modifying the molecular weight of the selected protein and the amine used for cationization. The most promising systems are nanoparticles based on intermediate molecular weight gelatin cationized with the endogenous amine spermine, which exhibit an adequate toxicological profile, as well as effective association and protection of pDNA or siRNA molecules, thereby resulting in higher transfection efficiency and gene silencing than the other studied formulations. Copyright © 2015 Elsevier B.V. All rights reserved.

Semi-crystalline photovoltaic polymers with siloxane-terminated hybrid side-chains

Institute of Scientific and Technical Information of China (English)

Yuxiang Li; Seyeong Song; Song Yi Park; Jin Young Kim; Han Young Woo

2017-01-01

Three types of semi-cry stalline photovoltaic polymers were synthesized by incorporating a siloxane-terminated organic/inorganic hybrid side-chain and changing the number of fluorine substituents.A branch point away from a polymer main backbone in the siloxane-containing side-chains and the intra-and/or interchain noncovalent coulombic interactions enhance a chain planarity and facile interchain organization.The resulting polymers formed strongly agglomerated films with high roughness,suggesting strong intermolecular interactions.The optical band gap of ca.1.7 eV was measured for all polymers with a pronounced shoulder peak due to tight π-π stacking.With increasing the fluorine substituents,the frontier energy levels decreased and preferential face-on orientation was observed.The siloxane-terminated side-chains and fluorine substitution promoted the intermolecular packing,showing well resolved lamellar scatterings up to（300） for this series of polymers in the grazing incidence wide angle X-ray scattering measurements.The PPsiDTBT,PPsiDTFBT and PPsiDT2 FBT devices showed a power conversion efficiency of 3.16%,4.40%and 5.65%,respectively,by blending with PC71BM.Langevin-type bimolecular charge recombination was similar for three polymeric solar cells.The main loss in the photocurrent generation for PPsiDTBT:PC71BM was interpreted to originate from the trap assisted charge recombination by measuring light-intensity dependent short-circuit current density(JSC) and open-circuit voltage(VOc).Our results provide a new insight into the rational selection of solubilizing substituents for optimizing crystalline interchain packing with appropriate miscibility with PC71 BM for further optimizing polymer solar cells.

Semi-crystalline photovoltaic polymers with siloxane-terminated hybrid side-chains

Institute of Scientific and Technical Information of China (English)

Yuxiang Li; Seyeong Song; Song Yi Park; Jin Young Kim; Han Young Woo

2017-01-01

Three types of semi-crystalline photovoltaic polymers were synthesized by incorporating a siloxane-terminated organic/inorganic hybrid side-chain and changing the number of fluorine substituents.A branch point away from a polymer main backbone in the siloxane-containing side-chains and the intra-and/or interchain noncovalent coulombic interactions enhance a chain planarity and facile interchain organization.The resulting polymers formed strongly agglomerated films with high roughness,suggesting strong intermolecular interactions.The optical band gap of ca.1.7 eV was measured for all polymers with a pronounced shoulder peak due to tight π-π stacking.With increasing the fluorine substituents,the frontier energy levels decreased and preferential face-on orientation was observed.The siloxane-terminated side-chains and fluorine substitution promoted the intermolecular packing,showing well resolved lamellar scatterings up to (300) for this series of polymers in the grazing incidence wide angle X-ray scattering measurements.The PPsiDTBT,PPsiDTFBT and PPsiDT2FBT devices showed a power conversion efficiency of 3.16％,4.40％ and 5.65％,respectively,by blending with PC71BM.Langevin-type bimolecular charge recombination was similar for three polymeric solar cells.The main loss in the photocurrent generation for PPsiDTBT:PC71BM was interpreted to originate from the trap assisted charge recombination by measuring light-intensity dependent short-circuit current density (Jsc) and open-circuit voltage (Voc).Our results provide a new insight into the rational selection of solubilizing substituents for optimizing crystalline interchain packing with appropriate miscibility with PC71BM for further optimizing polymer solar cells.

Development of a Sensitive Electrochemical Enzymatic Reaction-Based Cholesterol Biosensor Using Nano-Sized Carbon Interdigitated Electrodes Decorated with Gold Nanoparticles.

Science.gov (United States)

Sharma, Deepti; Lee, Jongmin; Seo, Junyoung; Shin, Heungjoo

2017-09-15

We developed a versatile and highly sensitive biosensor platform. The platform is based on electrochemical-enzymatic redox cycling induced by selective enzyme immobilization on nano-sized carbon interdigitated electrodes (IDEs) decorated with gold nanoparticles (AuNPs). Without resorting to sophisticated nanofabrication technologies, we used batch wafer-level carbon microelectromechanical systems (C-MEMS) processes to fabricate 3D carbon IDEs reproducibly, simply, and cost effectively. In addition, AuNPs were selectively electrodeposited on specific carbon nanoelectrodes; the high surface-to-volume ratio and fast electron transfer ability of AuNPs enhanced the electrochemical signal across these carbon IDEs. Gold nanoparticle characteristics such as size and morphology were reproducibly controlled by modulating the step-potential and time period in the electrodeposition processes. To detect cholesterol selectively using AuNP/carbon IDEs, cholesterol oxidase (ChOx) was selectively immobilized via the electrochemical reduction of the diazonium cation. The sensitivity of the AuNP/carbon IDE-based biosensor was ensured by efficient amplification of the redox mediators, ferricyanide and ferrocyanide, between selectively immobilized enzyme sites and both of the combs of AuNP/carbon IDEs. The presented AuNP/carbon IDE-based cholesterol biosensor exhibited a wide sensing range (0.005-10 mM) and high sensitivity (~993.91 µA mM -1 cm -2 ; limit of detection (LOD) ~1.28 µM). In addition, the proposed cholesterol biosensor was found to be highly selective for the cholesterol detection.

Colloidal lithography with electrochemical nickel deposition as a unique method for improved silver decorated nanocavities in SERS applications

Science.gov (United States)

Petruš, Ondrej; Oriňak, Andrej; Oriňaková, Renáta; Orságová Králová, Zuzana; Múdra, Erika; Kupková, Miriam; Kovaľ, Karol

2017-11-01

Two types of metallised nanocavities (single and hybrid) were fabricated by colloid lithography followed by electrochemical deposition of Ni and subsequently Ag layers. Introductory Ni deposition step iniciates more homogenous decoration of nanocavities with Ag nanoparticles. Silver nanocavity decoration has been so performed with lower nucleation rate and with Ag nanoparticles homogeinity increase. By this, two step Ni and Ag deposition trough polystyrene nanospheres (100, 300, 500, 700, 900 nm), the various Ag surfaces were obtained. Ni layer formation in the first step of deposition enabled more precise controlling of Ag film deposition and thus final Ag surface morphology. Prepared substrates were tested as active surfaces in SERS application. The best SERS signal enhancement was observed at 500 nm Ag nanocavities with normalised thickness Ni layer ∼0.5. Enhancement factor has been established at value 1.078 × 1010; time stability was determined within 13 weeks; charge distribution at nanocavity Ag surfaces as well as reflection spectra were calculated by FDTD method. Newly prepared nanocavity surface can be applied in SERS analysis, predominantly.

Anaphylaxis to gelatin-containing rectal suppositories.

Science.gov (United States)

Sakaguchi, M; Inouye, S

2001-12-01

Some children--though the number is few-have been sensitized with gelatin. To investigate the relationship between the presence of antigelatin IgE and anaphylaxis to gelatin-containing rectal suppository, we measured antigelatin IgE in the sera of the children with anaphylaxis. Ten children showed systemic allergic reactions, including anaphylaxis, to a chloral hydrate rectal suppository containing gelatin (231 mg/dose) that had been used as a sedative. These children's clinical histories and serum samples were submitted from physicians to the National Institute of Infectious Diseases during a 2-year period from 1996 to 1997. Of the 10 children, 5 showed apparent anaphylaxis, including hypotension and/or cyanosis, along with urticaria or wheezing; 2 showed both urticaria and wheezing without hypotension or cyanosis; the other 3 showed only urticaria. All of the children had antigelatin IgE (mean value +/- SD, 7.9 +/- 8.4 Ua/mL). As a control, samples from 250 randomly selected children had no antigelatin IgE. These findings suggest that the 10 children's systemic allergic reactions to this suppository were caused by the gelatin component. Gelatin-containing suppositories must be used with the same caution as gelatin-containing vaccines and other medications.

ZnO nanoparticles decorated on graphene sheets through liquid arc discharge approach with enhanced photocatalytic performance under visible-light

International Nuclear Information System (INIS)

Ashkarran, Ali Akbar; Mohammadi, Bahareh

2015-01-01

Graphical abstract: TEM image of ZnO–graphene composite. - Highlights: • Innovative approach for synthesis of zinc oxide–graphene (ZnO–G) hybrid nanostructures. • Combination of bottom-up and top-down methods. • Decoration of ZnO nanoparticles on the surface of graphene. • Visible-light photocatalytic performance. - Abstract: We present an innovative approach for synthesis of zinc oxide–graphene (ZnO–G) hybrid nanostructures through combination of improved hummer and arc discharge methods in liquid. A detailed study of the considerable visible-light photocatalytic activities of these nanostructures for the degradation of Phenol red (PR) and Methyl orange (MO) as standard organic compounds under the irradiation of 90 W halogen light for 2 h has been performed. The ZnO–G nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer Emmett Teller (BET) and ultra violet–visible absorption spectroscopy (UV–vis). The results revealed that the ZnO–G nanostructures extended the light absorption spectrum toward the visible region and remarkably enhanced the photodegradation of standard dyes under visible-light irradiation. It has been confirmed that the ZnO–G nanostructures could be excited by visible-light (E ∼ 2.6 eV). The major enhancement in the photocatalytic activity of ZnO–G nanostructures under visible-light irradiation can be attributed to the effect of electron transport among ZnO nanoparticles (NPs) and graphene sheets. A mechanism for photocatalytic degradation of organic pollutants over ZnO–G photocatalyst was proposed based on our observations

ZnO nanoparticles decorated on graphene sheets through liquid arc discharge approach with enhanced photocatalytic performance under visible-light

Energy Technology Data Exchange (ETDEWEB)

Ashkarran, Ali Akbar, E-mail: ashkarran@umz.ac.ir; Mohammadi, Bahareh

2015-07-01

Graphical abstract: TEM image of ZnO–graphene composite. - Highlights: • Innovative approach for synthesis of zinc oxide–graphene (ZnO–G) hybrid nanostructures. • Combination of bottom-up and top-down methods. • Decoration of ZnO nanoparticles on the surface of graphene. • Visible-light photocatalytic performance. - Abstract: We present an innovative approach for synthesis of zinc oxide–graphene (ZnO–G) hybrid nanostructures through combination of improved hummer and arc discharge methods in liquid. A detailed study of the considerable visible-light photocatalytic activities of these nanostructures for the degradation of Phenol red (PR) and Methyl orange (MO) as standard organic compounds under the irradiation of 90 W halogen light for 2 h has been performed. The ZnO–G nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer Emmett Teller (BET) and ultra violet–visible absorption spectroscopy (UV–vis). The results revealed that the ZnO–G nanostructures extended the light absorption spectrum toward the visible region and remarkably enhanced the photodegradation of standard dyes under visible-light irradiation. It has been confirmed that the ZnO–G nanostructures could be excited by visible-light (E ∼ 2.6 eV). The major enhancement in the photocatalytic activity of ZnO–G nanostructures under visible-light irradiation can be attributed to the effect of electron transport among ZnO nanoparticles (NPs) and graphene sheets. A mechanism for photocatalytic degradation of organic pollutants over ZnO–G photocatalyst was proposed based on our observations.

Stavudine loaded gelatin liposomes for HIV therapy: Preparation, characterization and in vitro cytotoxic evaluation

Energy Technology Data Exchange (ETDEWEB)

Nayak, Debasis; Boxi, Ankita; Ashe, Sarbani; Thathapudi, Neethi Chandra; Nayak, Bismita, E-mail: nayakb@nitrkl.ac.in

2017-04-01

Despite continuous research and availability of 25 different active compounds for treating chronic HIV-1 infection, there is no absolute cure for this deadly disease. Primarily, the residual viremia remains hidden in latently infected reservoir sites and persistently release the viral RNA into the blood stream. The study proposes the dual utilization of the prepared stavudine-containing nanoformulations to control the residual viremia as well as target the reservoir sites. Gelatin nanoformulations containing very low dosage of stavudine were prepared through classical desolvation process and were later loaded in soya lecithin-liposomes. The nanoformulations were characterized through dynamic light scattering (DLS), Transmission electron microscopy (TEM), X-ray diffraction (XRD) and ATR-FTIR. All the formulations were in nano regime with high hemocompatibility and exhibited dose-dependent cytotoxicity towards Raw 264.7 macrophages. Among the various formulations, SG-3 (Stavudine-Gelatin Nanoformulation sample 3) and SG-LP-3 (Stavudine-Gelatin Nano-Liposome formulation sample 3) showed the best results in terms of yield, size, charge, encapsulation efficiency, hemocompatibility and % cell viability. For the first time, liposomal delivery of antiretroviral drugs using nanocarriers has been demonstrated using very low dosage (lower than the recommended WHO dosage) showing the prominent linear release of stavudine for up to 12 h which would reduce the circulatory viremia as well as reach the sanctuary reservoir sites due to their nanosize. This method of liposomal delivery of antiretroviral drugs in very low concentrations using nanocarriers could provide a novel therapeutic alternative to target HIV reservoir sites. - Highlights: • Stavudine entrapped gelatin nanocarriers prepared with two step desolvation process • Linear and release of stavudine from liposomal formulations up to 12 h • All the SG nanoparticles and SG-LP formulations showed negligible

Stavudine loaded gelatin liposomes for HIV therapy: Preparation, characterization and in vitro cytotoxic evaluation

International Nuclear Information System (INIS)

Nayak, Debasis; Boxi, Ankita; Ashe, Sarbani; Thathapudi, Neethi Chandra; Nayak, Bismita

2017-01-01

Despite continuous research and availability of 25 different active compounds for treating chronic HIV-1 infection, there is no absolute cure for this deadly disease. Primarily, the residual viremia remains hidden in latently infected reservoir sites and persistently release the viral RNA into the blood stream. The study proposes the dual utilization of the prepared stavudine-containing nanoformulations to control the residual viremia as well as target the reservoir sites. Gelatin nanoformulations containing very low dosage of stavudine were prepared through classical desolvation process and were later loaded in soya lecithin-liposomes. The nanoformulations were characterized through dynamic light scattering (DLS), Transmission electron microscopy (TEM), X-ray diffraction (XRD) and ATR-FTIR. All the formulations were in nano regime with high hemocompatibility and exhibited dose-dependent cytotoxicity towards Raw 264.7 macrophages. Among the various formulations, SG-3 (Stavudine-Gelatin Nanoformulation sample 3) and SG-LP-3 (Stavudine-Gelatin Nano-Liposome formulation sample 3) showed the best results in terms of yield, size, charge, encapsulation efficiency, hemocompatibility and % cell viability. For the first time, liposomal delivery of antiretroviral drugs using nanocarriers has been demonstrated using very low dosage (lower than the recommended WHO dosage) showing the prominent linear release of stavudine for up to 12 h which would reduce the circulatory viremia as well as reach the sanctuary reservoir sites due to their nanosize. This method of liposomal delivery of antiretroviral drugs in very low concentrations using nanocarriers could provide a novel therapeutic alternative to target HIV reservoir sites. - Highlights: • Stavudine entrapped gelatin nanocarriers prepared with two step desolvation process • Linear and release of stavudine from liposomal formulations up to 12 h • All the SG nanoparticles and SG-LP formulations showed negligible

Preparation of platinum-decorated porous graphite nanofibers, and their hydrogen storage behaviors.

Science.gov (United States)

Kim, Byung-Joo; Lee, Young-Seak; Park, Soo-Jin

2008-02-15

In this work, the hydrogen storage behaviors of porous graphite nanofibers (GNFs) decorated by Pt nanoparticles were investigated. The Pt nanoparticles were introduced onto the GNF surfaces using a well-known chemical reduction method. We investigated the hydrogen storage capacity of the Pt-doped GNFs for the platinum content range of 1.3-7.5 mass%. The microstructure of the Pt/porous GNFs was characterized by X-ray diffraction and transmission electron microscopy. The hydrogen storage behaviors of the Pt/GNFs were studied using a PCT apparatus at 298 K and 10 MPa. It was found that amount of hydrogen stored increased with increasing Pt content to 3.4 mass%, and then decreased. This result indicates that the hydrogen storage capacity of porous carbons is based on both their metal content and dispersion rate.

Mitigating the effect of siloxanes on internal combustion engines using landfill gasses

Science.gov (United States)

Besmann, Theodore M

2014-01-21

A waste gas combustion method that includes providing a combustible fuel source, in which the combustible fuel source is composed of at least methane and siloxane gas. A sodium source or magnesium source is mixed with the combustible fuel source. Combustion of the siloxane gas of the combustible fuel source produces a silicon containing product. The sodium source or magnesium source reacts with the silicon containing product to provide a sodium containing glass or sodium containing silicate, or a magnesium containing silicate. By producing the sodium containing glass or sodium containing silicate, or the magnesium containing silicate, or magnesium source for precipitating particulate silica instead of hard coating, the method may reduce or eliminate the formation of silica deposits within the combustion chamber and the exhaust components of the internal combustion engine.

Molecular interactions in gelatin/chitosan composite films.

Science.gov (United States)

Qiao, Congde; Ma, Xianguang; Zhang, Jianlong; Yao, Jinshui

2017-11-15

Gelatin and chitosan were mixed at different mass ratios in solution forms, and the rheological properties of these film-forming solutions, upon cooling, were studied. The results indicate that the significant interactions between gelatin and chitosan promote the formation of multiple complexes, reflected by an increase in the storage modulus of gelatin solution. Furthermore, these molecular interactions hinder the formation of gelatin networks, consequently decreasing the storage modulus of polymer gels. Both hydrogen bonds and electrostatic interactions are formed between gelatin and chitosan, as evidenced by the shift of the amide-II bands of polymers. X-ray patterns of composite films indicate that the contents of triple helices decrease with increasing chitosan content. Only one glass transition temperature (T g ) was observed in composite films with different composition ratios, and it decreases gradually with an increase in chitosan proportion, indicating that gelatin and chitosan have good miscibility and form a wide range of blends. Copyright © 2017 Elsevier Ltd. All rights reserved.

Palladium nanoparticles decorated on activated fullerene modified screen printed carbon electrode for enhanced electrochemical sensing of dopamine.

Science.gov (United States)

Palanisamy, Selvakumar; Thirumalraj, Balamurugan; Chen, Shen-Ming; Ali, M Ajmal; Al-Hemaid, Fahad M A

2015-06-15

In the present work, an enhanced electrochemical sensor for dopamine (DA) was developed based on palladium nanoparticles decorated activated fullerene-C60 (AC60/PdNPs) composite modified screen printed carbon electrode (SPCE). The scanning electron microscopy and elemental analysis confirmed the formation of PdNPs on AC60. The fabricated AC60/PdNPs composite modified electrode exhibited an enhanced electrochemical response to DA with a lower oxidation potential than that of SPCE modified with PdNPs and C60, indicating the excellent electrooxidation behavior of the AC60/PdNPs composite modified electrode. The electrochemical studies confirmed that the electrooxidation of DA at the composite electrode is a diffusion controlled electrochemical process. The differential pulse voltammetry was employed for the determination of DA; under optimum conditions, the electrochemical oxidation signal of DA increased linearly at the AC60/PdNPs composite from 0.35 to 133.35 μM. The limit of detection was found as 0.056 μM with a sensitivity of 4.23 μA μM(-1) cm(-2). The good recovery of DA in the DA injection samples further revealed the good practicality of AC60/PdNPs modified electrode. Copyright © 2015 Elsevier Inc. All rights reserved.

Ultrasensitive and Selective Organic FET-type Nonenzymatic Dopamine Sensor Based on Platinum Nanoparticles-Decorated Reduced Graphene Oxide.

Science.gov (United States)

Oh, Jungkyun; Lee, Jun Seop; Jun, Jaemoon; Kim, Sung Gun; Jang, Jyongsik

2017-11-15

Dopamine (DA), a catecholamine hormone, is an important neurotransmitter that controls renal and cardiovascular organizations and regulates physiological activities. Abnormal concentrations of DA cause unfavorable neuronal illnesses such as Parkinson's disease, schizophrenia, and attention deficit hyperactivity disorder/attention deficit disorder. However, the DA concentration is exceedingly low in patients and difficult to detect with existing biosensors. In this study, we developed an organic field-effect-transistor-type (OFET) nonenzyme biosensor using platinum nanoparticle-decorated reduced graphene oxide (Pt_rGO) for ultrasensitive and selective DA detection. The Pt_rGOs were fabricated by reducing GO aqueous solution-containing Pt precursors (PtCl 4 ) with a chemical reducing agent. The Pt_rGOs were immobilized on a graphene substrate by π-π interactions and a conducting-polymer source-drain electrode was patterned on the substrate to form the DA sensor. The resulting OFET sensor showed a high sensitivity to remarkably low DA concentrations (100 × 10 -18 M) and selectivity among interfering molecules. Good stability was expected for the OFET sensor because it was fabricated without an enzymatic receptor, and π-π conjugation is a part of the immobilization process. Furthermore, the OFET sensors are flexible and offer the possibility of wide application as wearable and portable sensors.

Optical limiting in gelatin stabilized Cu-PVP nanocomposite colloidal suspension

Science.gov (United States)

Tamgadge, Y. S.; Gedam, P. P.; Thakare, N. B.; Talwatkar, S. S.; Sunatkari, A. L.; Muley, G. G.

2018-05-01

This article illustrates investigations on optical limiting properties of Cu-PVP nanocomposite colloidal suspension. Gelatin stabilized Cu nanoparticles have been synthesized using chemical reduction method and thin films in PVP matrix have been obtained using spin coating technique. Thin films have been characterized by X-ray diffraction (XRD), Ultraviolet-visible (UV-vis) spectroscopy, etc. for structural and linear optical studies. Optical limiting properties of Colloidal Cu-PVP nanocomposites have been investigated at 808 nm diode CW laser. Minimum optical limiting threshold was found for GCu3-PVP nanocomposites sample. The strong optical limiting is thermal in origin as CW laser is used and effects are attributed to thermal lensing effect.

Preparation of Polyacrylonitrile-Kapok Hollow Microtubes Decorated with Cu Nanoparticles

Directory of Open Access Journals (Sweden)

Agcaoili Apollo

2015-01-01

Full Text Available A novel copper (Cu nanoparticle carrier was fabricated using kapok natural microtubes as a substrate. Cu nanoparticles were grown on a thin polymer film on the surface of the kapok fibers. The polymer film was deposited on the surface of the microtube using a surfactant-assisted polymerization of acrylonitrile monomers. Cetyltrimethyl ammonium bromide (CTAB was used surfactant. The contact angle decreased from 120.5 to 0 after polyacrylonitrile coating (PAN, which suggests improved hydrophilicity of the kapok fibers. Addition of 1.5 mL acrylonitrile and 0.020 – 0.035 g CTAB yielded evenly coated kapok fibers. Cu nanoparticles, with diameters of 82-186 nm, were formed on the surface of the composite by reducing 0.16 M copper sulphate (CuSO4 with hydrazine (N2H4 at 70°C. EDX reveals that more Cu nanoparticles formed on the surface of PAN-kapok composites with 0.035g CTAB due to thicker PAN coating.

Presence of Siloxanes in the Biogas of a Wastewater Treatment Plant Separation in Condensates and Influence of the Dose of Iron Chloride on its Elimination

Energy Technology Data Exchange (ETDEWEB)

Mariano, García [Empresa Mixta de Aguas Residuales de Alicante, S.A. (EMARASA) (Spain); Daniel, Prats; Arturo, Trapote, E-mail: atj@ua.es [University Institute of Water and Environmental Sciences, University of Alicante (Spain)

2015-12-21

The siloxanes present in the biogas produced during anaerobic digestion damage the mechanism of cogeneration equipment and, consequently, negatively affect the energy valorization process. For this reason, the detection and elimination of these silicon-derived chemical compounds are a priority in the management of cogeneration facilities. In this regard, the objectives of this paper are, firstly, to characterize the siloxanes in the biogas and, secondly, to qualitatively evaluate the influence of the dose of iron chloride on its elimination. The research was performed at the Rincón de León Wastewater Treatment Plant (Alicante, Spain). The outflow biogas of the digesters and of the pressurized gasometers was sampled and analyzed. The results obtained made it possible to demonstrate, firstly, the absence of linear siloxanes and that, of the cyclic siloxanes, the predominant type was decamethylcyclopentasiloxane, and, secondly, that the addition of iron chloride in the digesters significantly reduces the siloxane content in the biogas. Additionally, it was demonstrated that the process of compression of the biogas, with the elimination of condensates, also produces significant reductions in the concentration of siloxanes in the biogas.

Presence of Siloxanes in the Biogas of a Wastewater Treatment Plant Separation in Condensates and Influence of the Dose of Iron Chloride on its Elimination

International Nuclear Information System (INIS)

Mariano, García; Daniel, Prats; Arturo, Trapote

2015-01-01

The siloxanes present in the biogas produced during anaerobic digestion damage the mechanism of cogeneration equipment and, consequently, negatively affect the energy valorization process. For this reason, the detection and elimination of these silicon-derived chemical compounds are a priority in the management of cogeneration facilities. In this regard, the objectives of this paper are, firstly, to characterize the siloxanes in the biogas and, secondly, to qualitatively evaluate the influence of the dose of iron chloride on its elimination. The research was performed at the Rincón de León Wastewater Treatment Plant (Alicante, Spain). The outflow biogas of the digesters and of the pressurized gasometers was sampled and analyzed. The results obtained made it possible to demonstrate, firstly, the absence of linear siloxanes and that, of the cyclic siloxanes, the predominant type was decamethylcyclopentasiloxane, and, secondly, that the addition of iron chloride in the digesters significantly reduces the siloxane content in the biogas. Additionally, it was demonstrated that the process of compression of the biogas, with the elimination of condensates, also produces significant reductions in the concentration of siloxanes in the biogas

Au nanostructure-decorated TiO2 nanowires exhibiting photoactivity across entire UV-visible region for photoelectrochemical water splitting.

Science.gov (United States)

Pu, Ying-Chih; Wang, Gongming; Chang, Kao-Der; Ling, Yichuan; Lin, Yin-Kai; Fitzmorris, Bob C; Liu, Chia-Ming; Lu, Xihong; Tong, Yexiang; Zhang, Jin Z; Hsu, Yung-Jung; Li, Yat

2013-08-14

Here we demonstrate that the photoactivity of Au-decorated TiO2 electrodes for photoelectrochemical water oxidation can be effectively enhanced in the entire UV-visible region from 300 to 800 nm by manipulating the shape of the decorated Au nanostructures. The samples were prepared by carefully depositing Au nanoparticles (NPs), Au nanorods (NRs), and a mixture of Au NPs and NRs on the surface of TiO2 nanowire arrays. As compared with bare TiO2, Au NP-decorated TiO2 nanowire electrodes exhibited significantly enhanced photoactivity in both the UV and visible regions. For Au NR-decorated TiO2 electrodes, the photoactivity enhancement was, however, observed in the visible region only, with the largest photocurrent generation achieved at 710 nm. Significantly, TiO2 nanowires deposited with a mixture of Au NPs and NRs showed enhanced photoactivity in the entire UV-visible region. Monochromatic incident photon-to-electron conversion efficiency measurements indicated that excitation of surface plasmon resonance of Au is responsible for the enhanced photoactivity of Au nanostructure-decorated TiO2 nanowires. Photovoltage experiment showed that the enhanced photoactivity of Au NP-decorated TiO2 in the UV region was attributable to the effective surface passivation of Au NPs. Furthermore, 3D finite-difference time domain simulation was performed to investigate the electrical field amplification at the interface between Au nanostructures and TiO2 upon SPR excitation. The results suggested that the enhanced photoactivity of Au NP-decorated TiO2 in the UV region was partially due to the increased optical absorption of TiO2 associated with SPR electrical field amplification. The current study could provide a new paradigm for designing plasmonic metal/semiconductor composite systems to effectively harvest the entire UV-visible light for solar fuel production.

Preservation and storage of prepared ballistic gelatine.

Science.gov (United States)

Mattijssen, E J A T; Alberink, I; Jacobs, B; van den Boogaard, Y

2016-02-01

The use of ballistic gelatine, generally accepted as a human muscle tissue simulant in wound ballistic studies, might be improved by adding a preservative (Methyl 4-hydroxybenzoate) which inhibits microbial growth. This study shows that replacing a part of the gelatine powder by the preservative does not significantly alter the penetration depth of projectiles. Storing prepared blocks of ballistic gelatine over time decreased the penetration depth of projectiles. Storage of prepared gelatine for 4 week already showed a significant effect on the penetration depth of projectiles. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Polyvinyl siloxane: novel material for external nasal splinting.

Science.gov (United States)

Jayakumar, N K; Rathnaprabhu, V; Ramesh, S; Parameswaran, A

2016-01-01

External nasal splinting is performed routinely after nasal bone fracture reductions, osteotomies, and rhinoplasties. Materials commonly used include plaster of Paris (POP), thermoplastic splints, self-adhesive padded aluminium splints, and Orthoplast, among many others. The disadvantages of these materials are described in this paper, and polyvinyl siloxane is recommended as an effective and more readily available alternative material to counter these pitfalls. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Structure-property correlation study of novel poly(urethane-ester-siloxane) networks

Czech Academy of Sciences Publication Activity Database

Pergal, M. V.; Džunuzović, J. V.; Poreba, Rafal; Steinhart, Miloš; Pergal, M. M.; Vodnik, V. V.; Špírková, Milena

2013-01-01

Roč. 52, č. 18 (2013), s. 6164-6176 ISSN 0888-5885 R&D Projects: GA ČR GAP108/10/0195 Institutional support: RVO:61389013 Keywords : urethane-siloxane copolymers * hyperbranched poly ester * mechanical - properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.235, year: 2013

Characterization of Fish Skin Gelatin Yellowfin Tuna

Directory of Open Access Journals (Sweden)

Mala Nurilmala

2017-08-01

Full Text Available Gelatin is one of the products which become a necessity for various industries, i.e. food and non-food industries. The application of gelatin has been increasing year by year in Indonesia. However, there is nogelatin industry in Indonesia so far. Thus, it is necessary to find an alternative source of gelatin, especially from fishery by products.Thus, the purpose of this research was to extract fish skin gelatin of yellowfin tuna with temperature treatments (55, 65 and 75oC. In addition, the properties of resulted gelatin were determined including yield, pH, gel strength, viscosity, functional groups, molecular weight profiles, and amino acid composition. The extraction at 75oC was chosen as the best result. The yield was 17%; pH 5.3; gel strength 1789.55 gf, viscosity 104.2 Cp, respectively. There was functional group amide A, I, II, dan III. SDS-PAGE showed β, α1 dan α2 bands for tuna skin gelatin. In addition, the main amino acids were glycine and proline.

Mechanochemical activation and patterning of an adhesive surface toward nanoparticle deposition.

Science.gov (United States)

Baytekin, H Tarik; Baytekin, Bilge; Huda, Sabil; Yavuz, Zelal; Grzybowski, Bartosz A

2015-02-11

Mechanical pulling of adhesive tape creates radicals on the tape's surface. These radicals are capable of reducing metal salts to the corresponding metal nanoparticles. In this way, the mechanically activated tape can be decorated with various types of nanoparticles, including Au, Ag, Pd, or Cu. While retaining their mechanical properties and remaining "sticky," the tapes can exhibit new properties derived from the presence of metal nanoparticles (e.g., bacteriostaticity, increased electrical conductivity). They can also be patterned with nanoparticles only at selective locations of mechanical activation.

Fabrication and Physical Evaluation of Gelatin-Coated Carbonate Apatite Foam

Directory of Open Access Journals (Sweden)

Kanae Hara

2016-08-01

Full Text Available Carbonate apatite (CO3Ap foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO3Ap foam for bone replacement, CO3Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO3Ap foam was 74 kPa whereas that of the gelatin-reinforced CO3Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO3Ap foam.

Decoration Increases the Conspicuousness of Raptor Nests.

Science.gov (United States)

Canal, David; Mulero-Pázmány, Margarita; Negro, Juan José; Sergio, Fabrizio

2016-01-01

Avian nests are frequently concealed or camouflaged, but a number of species builds noticeable nests or use conspicuous materials for nest decoration. In most cases, nest decoration has a role in mate choice or provides thermoregulatory or antiparasitic benefits. In territorial species however, decorations may serve additional or complementary functions, such as extended phenotypic signaling of nest-site occupancy and social status to potential intruders. The latter may benefit both signaler and receiver by minimizing the risk of aggressive interactions, especially in organisms with dangerous weaponry. Support for this hypothesis was recently found in a population of black kites (Milvus migrans), a territorial raptor that decorates its nest with white artificial materials. However, the crucial assumption that nest decorations increased nest-site visibility to conspecifics was not assessed, a key aspect given that black kite nests may be well concealed within the canopy. Here, we used an unmanned aircraft system to take pictures of black kite nests, with and without an experimentally placed decoration, from different altitudes and distances simulating the perspective of a flying and approaching, prospecting intruder. The pictures were shown to human volunteers through a standardized routine to determine whether detection rates varied according the nest decoration status and distance. Decorated nests consistently showed a higher detection frequency and a lower detection-latency, compared to undecorated versions of the same nests. Our results confirm that nest decoration in this species may act as a signaling medium that enhances nest visibility for aerial receivers, even at large distances. This finding complements previous work on this communication system, which showed that nest decoration was a threat informing trespassing conspecifics on the social dominance, territory quality and fighting capabilities of the signaler.

Green Synthesis of Silver Nanoparticles and the Study of Optical Properties

OpenAIRE

Vasireddy, Ramakrishna; Paul, Rima; Mitra, Apurba Krishna

2012-01-01

The synthesis of silver nanoparticles of varying size has been achieved using different molar concentrations of NaOH while the effect of changing the temperature has been studied. AgNO3, gelatine, glucose and NaOH are used as a silver precursor, stabilizer, reducing agent and accelerator respectively. The synthesized nanoparticles have been characterized by a FESEM study, X‐ray diffractometry, Raman spectroscopy and UV‐vis spectroscopy. The colloidal sols of the silver nanoparticles in a biop...

Homogeneously dispersed CeO2 nanoparticles on exfoliated hexaniobate nanosheets

Science.gov (United States)

Marques, Thalles M. F.; Strayer, Megan E.; Ghosh, Anupama; Silva, Alexandre; Ferreira, Odair P.; Fujisawa, Kazunori; Alves da Cunha, Jose R.; Abreu, Guilherme J. P.; Terrones, Mauricio; Mallouk, Thomas E.; Viana, Bartolomeu C.

2017-12-01

Hexaniobate nanosheets derived from the parent compound K4Nb6O17 have been decorated with CeO2 nanoparticles by ion exchange with aqueous cerium (IV) solution. Very homogeneous CeO2 nanoparticle decoration of the hexaniobate sheets can be achieved by this method and the resulting composites may absorb visible light. HRTEM images show that ∼3.0 nm diameter CeO2 nanoparticles adhere to hexaniobate nanosheets that are exfoliated and then restacked prior to Ce deposition. The interfacial interaction between CeO2 nanoparticles and nanosheets would be due to an electrostatic attraction mechanism. Raman and XRD measurements have given strong evidence that CeO2 nanoparticles have fluorite structure. EDS, FTIR and XPS results suggest almost complete exchange of TBA+ and K+ by Ce4+. Cerium ion exchange on the acid exchanged parent compound, H2.9K1.1Nb6O17, revealed that the extent of Ce ion exchange is much greater in case of nanosheets, which may be rationalized by the larger surface area available after exfoliation. XPS measurements show that the ratio of Ce4+/Ce3+ is around 4.4, in agreement with the formation of fluorite structure (CeO2). Thus, these CeO2 nanoparticle/nanosheet composites may be useful for catalytic processes.

Basic Cake Decorating Workbook.

Science.gov (United States)

Bogdany, Mel

Included in this student workbook for basic cake decorating are the following: (1) Drawings of steps in a basic way to ice a layer cake, how to make a paper cone, various sizes of flower nails, various sizes and types of tin pastry tubes, and special rose tubes; (2) recipes for basic decorating icings (buttercream, rose paste, and royal icing);…

Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

KAUST Repository

Gemici, Zekeriyya; Schwachulla, Patrick I.; Williamson, Erik H.; Rubner, Michael F.; Cohen, Robert E.

2009-01-01

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

KAUST Repository

Gemici, Zekeriyya

2009-03-11

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Targeted functionalization of nanoparticle thin films via capillary condensation.

Science.gov (United States)

Gemici, Zekeriyya; Schwachulla, Patrick I; Williamson, Erik H; Rubner, Michael F; Cohen, Robert E

2009-03-01

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane).

Operational features of decorative concrete

Science.gov (United States)

Bazhenova, Olga; Kotelnikov, Maxim

2018-03-01

This article deals with the questions of creation and use of decorative and finishing concrete and mortar. It has been revealed that the most effective artificial rock-imitating stone materials are those made of decorative concrete with the opened internal structure of material. At the same time it is important that the particles of decorative aggregate should be distributed evenly in the concrete volume. It can be reached only at a continuous grain-size analysis of the aggregate from the given rock. The article tackles the necessity of natural stone materials imitation for the cement stone color to correspond to the color of the rock. The possibility of creation of the decorative concrete imitating rocks in the high-speed turbulent mixer is considered. Dependences of durability and frost resistance of the studied concrete on the pore size and character and also parameters characterizing crack resistance of concrete are received.

Volatile methyl siloxanes (VMS) concentrations in outdoor air of several Catalan urban areas

Science.gov (United States)

Gallego, E.; Perales, J. F.; Roca, F. J.; Guardino, X.; Gadea, E.

2017-04-01

Volatile methyl siloxanes (VMS) were evaluated in ten Catalan urban areas with different industrial impacts, such as petrochemical industry, electrical and mechanical equipment, metallurgical and chemical industries, municipal solid waste treatment plant and cement and food industries, during 2013-2015. 24 h samples were taken with LCMA-UPC pump samplers specially designed in our laboratory, with a flow range of 70 ml min-1. A sorbent-based sampling method, successfully developed to collect a wide-range of VOC, was used. The analysis was performed by automatic thermal desorption coupled with capillary gas chromatography/mass spectrometry detector. The presented methodology allows the evaluation of VMS together with a wide range of other VOC, increasing the number of compounds that can be determined in outdoor air quality assessment of urban areas. This aspect is especially relevant as a restriction of several VMS (D4 and D5) in consumer products has been made by the European Chemicals Agency and US EPA is evaluating to include D4 in the Toxic Substances Control Act, regarding the concern of the possible effects of these compounds in human health and the environment. ΣVMS concentrations (L2-L5, D3-D6 and trimethylsilanol) varied between 0.3 ± 0.2 μg m-3 and 18 ± 12 μg m-3, determined in a hotspot area. Observed VMS concentrations were generally of the same order of magnitude than the previously determined in Barcelona, Chicago and Zurich urban areas, but higher than the published from suburban sites and Arctic locations. Cyclic siloxanes concentrations were up to two-three orders of magnitude higher than those of linear siloxanes, accounting for average contributions to the total concentrations of 97 ± 6% for all samples except for the hotspot area, where cyclic VMS accounted for 99.9 ± 0.1%. D5 was the most abundant siloxane in 5 sampling points; however, differing from the generally observed in previous studies, D3 was the most abundant compound in the

High-Performance and Simply-Synthesized Ladder-Like Structured Methacrylate Siloxane Hybrid Material for Flexible Hard Coating

Directory of Open Access Journals (Sweden)

Yun Hyeok Kim

2018-04-01

Full Text Available A high performance ladder-like structured methacrylate siloxane hybrid material (LMSH was fabricated via simple hydrolytic sol–gel reaction, followed by free-radical polymerization. A structurally ordered siloxane backbone, the ladder-like structure, which is an essential factor for high performance, could be achieved by a short period of sol–gel reaction in only 4 h. This results in superior optical (Transmittance > 90% at 550 nm, thermal (T5 wt % decomposition > 400 ℃ , mechanical properties(elastic recovery = 0.86, hardness = 0.6 GPa compared to the random- and even commercialized cage-structured silsesquioxane, which also has ordered structure. It was investigated that the fabricated ladder-like structured MSH showed the highest overall density of organic/inorganic co-networks that are originated from highly ordered siloxane network, along with high conversion rate of polymerizable methacrylate groups. Our findings suggest a potential of the ladder-like structured MSH as a powerful alternative for the methacrylate polysilsesquioxane, which can be applied to thermally stable and flexible optical coatings, even with an easier and simpler preparation process.

Self-assembling siloxane bilayer directly on SiO2 surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives.

Science.gov (United States)

Chen, Ying; Xu, Pengcheng; Li, Xinxin

2010-07-02

This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO(2) surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable Au-S bonds. For modifying the long-term reliable sensing bilayer on the piezoresistor-integrated micro-cantilevers, a siloxane-head bottom layer is self-assembled directly on the SiO(2) cantilever surface, which is followed by grafting another explosive-sensing-group functionalized molecule layer on top of the siloxane layer. The siloxane-modified sensor has experimentally exhibited a highly resoluble response to 0.1 ppb TNT vapor. More importantly, the repeated detection results after 140 days show no obvious attenuation in sensing signal. Also observed experimentally, the specific adsorption of the siloxane sensing bilayer to TNT molecules causes a tensile surface stress on the cantilever. Herein the measured tensile surface stress is in contrast to the compressive surface stress normally measured from conventional cantilever sensors where the sensitive thiol-SAMs are modified on an Au surface. The reason for this newly observed phenomenon is discussed and preliminarily analyzed.

Self-assembling siloxane bilayer directly on SiO2 surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives

International Nuclear Information System (INIS)

Chen Ying; Xu Pengcheng; Li Xinxin

2010-01-01

This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO 2 surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable Au-S bonds. For modifying the long-term reliable sensing bilayer on the piezoresistor-integrated micro-cantilevers, a siloxane-head bottom layer is self-assembled directly on the SiO 2 cantilever surface, which is followed by grafting another explosive-sensing-group functionalized molecule layer on top of the siloxane layer. The siloxane-modified sensor has experimentally exhibited a highly resoluble response to 0.1 ppb TNT vapor. More importantly, the repeated detection results after 140 days show no obvious attenuation in sensing signal. Also observed experimentally, the specific adsorption of the siloxane sensing bilayer to TNT molecules causes a tensile surface stress on the cantilever. Herein the measured tensile surface stress is in contrast to the compressive surface stress normally measured from conventional cantilever sensors where the sensitive thiol-SAMs are modified on an Au surface. The reason for this newly observed phenomenon is discussed and preliminarily analyzed.

Fatigue Resistance of Filled NR with PMMA-Wrapped and Rare Earth-Doped Alumina-Siloxane Gel

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

Poly (methyl methacrylate) (PMMA) was used to wrap alumina-siloxane sol which was produced by water glass, aluminum nitrate and α-methacrylic acid, and as a result, alumina-siloxane gel wrapped by PMMA was obtained. Meanwhile, rare earth ions were employed to dope in the course of reaction, and the formed rare earth doped PMMA microcapsule powder was filled into natural rubber (NR). It is found through the analysis of mechanical properties that Young′s modulus universally improves and a remarkable resistance to fatigue is displayed. Retention rate of tensile strength is twice that of the controlled sample after ten thousand times of extension fatigue.

Ag-decorated Fe{sub 3}O{sub 4}@SiO{sub 2} core-shell nanospheres: Seed-mediated growth preparation and their antibacterial activity during the consecutive recycling

Energy Technology Data Exchange (ETDEWEB)

Li, Miaomiao; Wu, Wenjie [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Qiao, Ru, E-mail: qiaoru@zjnu.cn [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Tan, Linxiang [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Li, Zhengquan [Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Zhang, Yong [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Department of Biomedical Engineering, National University of Singapore 117575 (Singapore)

2016-08-15

We demonstrated a seed-mediated growth approach to synthesize Ag nanoparticles-decorated Fe{sub 3}O{sub 4}@SiO{sub 2} core-shell nanospheres without use of surface functionalization. The particle size and decoration density of the immobilized Ag nanoparticles on SiO{sub 2} surface were tunable by adjusting the added AgNO{sub 3} concentration and the alternating repetition times in seed-mediated growth procedure. The as-prepared Ag-decorated Fe{sub 3}O{sub 4}@SiO{sub 2} nanospheres exhibited excellent antibacterial activities against Escherichia coli, Bacillus subtilis and Candida albicans, in which the minimum inhibitory concentration were 12.5 μg mL{sup −1}, 50 μg mL{sup −1} and 50 μg mL{sup −1}, respectively. It is speculated that their antibacterial activity is attributed to both the interaction of released Ag ions with the functional groups of vital enzymes and proteins and the strong oxidation of reactive oxygen species generated under the action of photoinduced electrons in Ag nanoparticles. Besides studying their antibacterial mechanism, we also investigated the variation of antibacterial activity of these heterostructured nanospheres during the consecutive magnetic separation and recycling. It shows that the magnetic antibacterial agent could be reused and its activity remained stable even after nine cycles, which enable it to be promisingly applied in biomedical areas. - Highlights: • Ag-decorated Fe{sub 3}O{sub 4}@SiO{sub 2} were synthesized via a seed-mediated growth method. • The core-shell heterostructures exhibited excellent antibacterial activity. • The activity was attributed to the effect of released Ag{sup +} with ROS oxidation. • The antibacterial agent was reused during magnetic separation and recycling.

Extraction and electrospinning of gelatin from fish skin.

Science.gov (United States)

Songchotikunpan, Panida; Tattiyakul, Jirarat; Supaphol, Pitt

2008-04-01

Ultra-fine gelatin fibers were successfully fabricated by electrospinning from the solutions of Nile tilapia (Oreochromis niloticus) skin-extracted gelatin in either acetic acid or formic acid aqueous solutions. The extracted gelatin contained 7.3% moisture, 89.4% protein, 0.3% lipid, and 0.4% ash contents (on the basis of wet weight), while the bloom gel strength, the shear viscosity, and the pH values were 328 g, 17.8 mPa s, and 5.0, respectively. Both the acid concentration and the concentration of the gelatin solutions strongly influenced the properties of the as-prepared solutions and the obtained gelatin fibers. At low acid concentrations (i.e., 15% (w/v) extracted gelatin solutions in 10 and 20% (v/v) acetic acid solvents or 10-60% (v/v) formic acid solvents), a combination between smooth and beaded fibers was observed. At low concentrations of the gelatin solutions in either 40% (v/v) acetic acid solvent or 80% (v/v) formic acid solvent (i.e., 5-11%, w/v), either discrete beads or beaded fibers were obtained, while, at higher concentrations (i.e., 14-29%, w/v), only smooth or a combination of smooth and beaded fibers were obtained. The average diameters of the obtained fibers, regardless of the types of the acid solvents used, ranged between 109 and 761 nm. Lastly, cross-linking of the obtained gelatin fiber mats with glutaraldehyde vapor caused slight shrinkage from their original dimension, and the cross-linked gelatin fiber mats became stiffer.

An ultrasensitive sandwich type electrochemiluminescence immunosensor for triiodothyronine detection using silver nanoparticle-decorated graphene oxide as a nanocarrier.

Science.gov (United States)

Chou, Hung-Tao; Fu, Chien-Yu; Lee, Chi-Young; Tai, Nyan-Hwa; Chang, Hwan-You

2015-09-15

An ultrasensitive electrochemiluminescence (ECL) immunosensor was constructed to detect 3,3',5-triiodothyronine (T3). The system employed T3-conjugated, silver nanoparticle-decorated carboxylic graphene oxide (Ag@fGO-T3) as a carrier and anti-T3 antibody-tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)3(2+)) as a probe. The Ag@fGO-T3 and Ru(bpy)3(2+) complex could be mobilized rapidly to the anode in the reaction chamber through electrophoresis. The fGO is reduced electrochemically at the electrode, and the electrons could transfer from an anode to the Ru(bpy)3(2+). The complex is excited at the electrode and an ECL signal is produced upon reacting with tripropylamine (TPrA). Because of its large surface area and excellent conductivity, Ag@fGO could enhance ECL signal significantly in the system. Quantitative measurement of T3 could be achieved in the range from 0.1 pg/mL to 0.8 ng/mL with a detection limit of 0.05 pg/mL. In addition, the novel immunosensor showed good specificity in the presence of serum, indicating its high potential in clinical use. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation and Evaluation of Gelatin-Chitosan-Nanobioglass 3D Porous Scaffold for Bone Tissue Engineering

OpenAIRE

Maji, Kanchan; Dasgupta, Sudip; Pramanik, Krishna; Bissoyi, Akalabya

2016-01-01

The aim of the present study was to prepare and characterize bioglass-natural biopolymer based composite scaffold and evaluate its bone regeneration ability. Bioactive glass nanoparticles (58S) in the size range of 20?30?nm were synthesized using sol-gel method. Porous scaffolds with varying bioglass composition from 10 to 30?wt% in chitosan, gelatin matrix were fabricated using the method of freeze drying of its slurry at 40?wt% solids loading. Samples were cross-linked with glutaraldehyde t...

Radiation chemical route for preparation of metal nanoparticles

International Nuclear Information System (INIS)

Kapoor, S.; Mukherjee, T.

2006-01-01

Nanoparticles show properties that are neither seen in the bulk or at atomic level. The unusual properties are governed by quantum size effect. Due to this various methodologies have been endeavored to control the size of the particles. In the present work we show the use of two complimentary techniques (radiation and photo) to synthesize and control the size of the metal particles. In-situ synthesis of fine silver, thallium and cadmium particles has been carried out by gamma-irradiation and electron pulse irradiation at room temperature in the pre-organized gel of polyacrylamide or cyclodextrin cavity. The role of generation of nuclei in high concentrations in stabilization of metal nanoparticles in hydrophobic cavity is shown. Similarly the importance of entrapment of metal ions in the polymer matrix during its formation is highlighted. The work is further extended to exploit the microemulsion droplets for stabilization of Cd nanoparticles. Utility of pulse radiolysis in probing the mechanism of the formation of metal nanoparticles is also shown. Ultrafast laser pulses were employed to control the morphology of the pre-prepared Pt nanoparticles. The changes in reduction of shape and size are considered to occur through melting and vaporization of the nanoparticles. Pt nanoparticles were coated on the inner walls of the tubular pyrex reactor and tested for their catalytic activity for oxidation of CO. It was observed that Pt nanoparticles prepared in the presence of a stabilizer (gelatin) showed a higher tendency to adhere to the inner walls of the pyrex reactor as compared to that prepared in the presence of silica nanoparticles. The catalyst was found to be active at ≥150 degree C giving CO 2 . Chemically reduced Pt nanoparticles stabilized on silica nanoparticles gave ∼7% CO conversion per hr. However, radiolytically prepared Pt nanoaprticles stabilized by gelatin gave ∼10% conversion per hr. The data indicates that catalytic oxidation of CO takes place

Environmentally friendly synthesis of highly monodisperse biocompatible gold nanoparticles with urchin-like shape.

Science.gov (United States)

Lu, Lehui; Ai, Kelong; Ozaki, Yukihiro

2008-02-05

We report a facile and environmentally friendly strategy for high-yield synthesis of highly monodisperse gold nanoparticles with urchin-like shape. A simple protein, gelatin, was first used for the control over shape and orientation of the gold nanoparticles. These nanoparticles, ready to use for biological systems, are promising in the optical imaging-based disease diagnostics and therapy because of their tunable surface plasmon resonance (SPR) and excellent surface-enhanced Raman scattering (SERS) activity.

Solubilization of bovine gelatin using power ultrasound: gelation without heating.

Science.gov (United States)

Farahnaky, Asgar; Zendeboodi, Fatemeh; Azizi, Rezvan; Mesbahi, Gholamreza; Majzoobi, Mahsa

2017-04-01

The aim of this study was to investigate the efficacy of power ultrasound without using any heating stage in solubilizeing gelatin dispersions, and to characterize the mechanical and microstructural properties of the resulting gels using texture analysis and scanning electron microscopy, respectively. Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. For solubilising gelatin, an ultrasound equipment with a frequency of 20 kHz, amplitude of 100% and power range of 50-150 W was used. Aqueous gelatin dispersions (4% w/v) were subjected to ultrasound for different times (40-240 s) at a constant temperature of 13C. Applying ultrasound to gelatin dispersions caused increases in water absorption and water solubility of the hydrocolloid. The textural parameters of the resulting gelatin gels, increased with increasing time and power of ultrasound. Moreover, a generalized Maxwell model with three elements was used for calculating relaxation times of the gels. The microstructural observations by SEM showed that the structural cohesiveness of the gels increased by increasing ultrasonication time. Ultrasound-assisted solubilization of gelatin can have emerging implications for industrial uses in pharmaceuticals, food and non-food systems. Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. Therefore, the use of gelatin as a hydrocolloid in food processings or pharmaceutical formulations which lack a heating step has been a technological and practical challenge. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. Ultrasound-assisted solubilisation of gelatin can have emerging implications for industrial uses in pharmaceuticals

Preparation and characterization of hydroxyapatite/gelatin composite membranes for immunoisolation

Science.gov (United States)

Chen, Jyh-Ping; Chang, Feng-Nian

2012-12-01

Composite membranes are fabricated from hydroxyapatite (HAP) and gelatin for immunoisolation of cells. The films were fabricated by crosslinking 5 wt%, 10 wt%, and 20 wt% gelatin with 1 wt% glutaraldehyde (GA) in the presence of HAP. Fourier transform infrared spectroscopy analysis confirms imide bond formation between GA and gelatin, while the crystal structure of HAP powder remains unchanged from X-ray diffraction analysis. The degree of crosslinking depends on crosslinking time and gelatin concentration. For 5% and 10% gelatin, the degree of crosslinking levels off at 90% within 48 h. From scanning electron microscopy micrographs, the microstructure of the composite membrane depends on the amount of gelatin used in the crosslinking reaction. The mechanical strength of the composite membrane could be enhanced by increasing the gelatin concentration. BET analysis indicates that pore size of the micropores on the surface HAP/gelatin agglomerates decreases with increasing gelatin concentration. However, the macropore, through which diffusion of molecules occurs, is larger at higher gelatin concentrations. The permeability coefficients of different molecules through a HAP/gelatin composite membrane increase with increasing gelatin concentration and is inversely correlated with the molecular weight of the molecule. For immunoisolation of cells, the diffusion of large molecules stimulated by the immune system can be rejected by a chamber constructed from the HAP/gelatin membrane. Insulinoma cells were encapsulated in alginate-poly-L-lysine-alginate microcapsules and enclosed in a HAP/gelatin chamber. The chamber did not impair the viability and function of insulinoma cells and cells can secrete insulin in response to glucose concentration change. The chamber is therefore useful for the physiologically controlled secretion of insulin in response to the blood glucose level. Intraperitoneal transplantation of the chamber into streptozotocin-induced diabetic SD rats could

Ultrathin Bi2WO6 nanosheet decorated with Pt nanoparticles for efficient formaldehyde removal at room temperature

Science.gov (United States)

Sun, Dong; Le, Yao; Jiang, Chuanjia; Cheng, Bei

2018-05-01

Two-dimensional (2D) ultrathin bismuth tungstate (Bi2WO6) nanosheets (BWO-NS) with a thickness of approximately 4.0 nm were synthesized by a one-step hydrothermal method, and decorated with platinum (Pt) nanoparticles (NPs) via an impregnation/borohydride-reduction approach. The as-prepared ultrathin Pt-BWO-NS exhibited superior catalytic activity for removing gaseous formaldehyde (HCHO) at ambient temperature, in comparison with bulk counterpart with Bi2WO6 sheet thickness of tens of nanometers. The ultrathin structure endowed the Pt-BWO-NS sample with larger specific surface area, which can provide abundant surface active sites for HCHO adsorption and facilitate the homogeneous dispersion of Pt NPs. X-ray photoelectron spectroscopy and hydrogen temperature-programmed reduction analyses revealed the interaction between the Bi2WO6 support and Pt species, which is crucial for activating surface oxygen atoms to participate in the catalytic HCHO oxidation process. By conducting in situ diffuse reflectance infrared Fourier transform spectroscopy under different atmospheres, i.e., gaseous HCHO in nitrogen or oxygen (O2), the reaction mechanism and the role of O2 were elucidated, with dioxymethylene, formate and linearly adsorbed carbon monoxide identified as the main reaction intermediates. This study may provide new enlightenment on fabricating novel 2D nanomaterials for efficient indoor air purification and potentially other environmental applications.

Using air, soil and vegetation to assess the environmental behaviour of siloxanes

DEFF Research Database (Denmark)

Ratola, N.; Ramos, S.; Homem, V.

2016-01-01

This study aimed to contribute to the enhancement of the knowledge of levels, trends and behaviour of eight siloxanes (four linear and four cyclic) in the environment. Adding to the prioritised scrutiny of the incidence in the atmosphere through passive samplers (sorbent-impregnated polyurethane...

Spontaneous decoration of Au nanoparticles on micro-patterned reduced graphene oxide shaped by focused laser beam

International Nuclear Information System (INIS)

Wan, Y. C.; Tok, E. S.; Teoh, H. F.; Sow, C. H.

2015-01-01

We report a facile, two-step method for the micro-landscaping of Au nanoparticles(NPs) on reduced graphene oxide (rGO) film en route to micro-patterned Au(NPs)-rGO hybrid functional materials. This method employs a focused laser beam to first locally convert GO to rGO before immersing the micro-patterned GO-rGO film into HAuCl 4 solution. The rGO micro-pattern, shaped by the focused laser beam, serves as nucleation sites for the reduction of Au ions. The reduction mechanism that governs the decoration of Au NPs on rGO films is akin to electroless deposition process. In this instance, surface charges that are formed during laser reduction of GO to rGO provide active nucleation sites for Au 3+ ions to form Au NPs when HAuCl 4 solution is introduced. The number density, the size, and size distribution of the Au NPs can thus be directly tuned and preferentially anchored onto the rGO micro-pattern by varying the incident laser power, the scanning speed of the laser, or the concentration of HAuCl 4 . The resulting hybrid materials can be used as a substrate for Surface Enhanced Raman Spectroscopy (SERS). Using Rhodamine 6G as the test subject, we found an improvement of SERS enhancement over bare rGO of up to four times, depending on the size of the Au NPs

Spontaneous decoration of Au nanoparticles on micro-patterned reduced graphene oxide shaped by focused laser beam

Energy Technology Data Exchange (ETDEWEB)

Wan, Y. C.; Tok, E. S. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Teoh, H. F. [Graduate School of Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456 (Singapore); Sow, C. H. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Graduate School of Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456 (Singapore)

2015-02-07

We report a facile, two-step method for the micro-landscaping of Au nanoparticles(NPs) on reduced graphene oxide (rGO) film en route to micro-patterned Au(NPs)-rGO hybrid functional materials. This method employs a focused laser beam to first locally convert GO to rGO before immersing the micro-patterned GO-rGO film into HAuCl{sub 4} solution. The rGO micro-pattern, shaped by the focused laser beam, serves as nucleation sites for the reduction of Au ions. The reduction mechanism that governs the decoration of Au NPs on rGO films is akin to electroless deposition process. In this instance, surface charges that are formed during laser reduction of GO to rGO provide active nucleation sites for Au{sup 3+} ions to form Au NPs when HAuCl{sub 4} solution is introduced. The number density, the size, and size distribution of the Au NPs can thus be directly tuned and preferentially anchored onto the rGO micro-pattern by varying the incident laser power, the scanning speed of the laser, or the concentration of HAuCl{sub 4}. The resulting hybrid materials can be used as a substrate for Surface Enhanced Raman Spectroscopy (SERS). Using Rhodamine 6G as the test subject, we found an improvement of SERS enhancement over bare rGO of up to four times, depending on the size of the Au NPs.

Thermoresponsive polyurethane/siloxane membrane for wound dressing and cell sheet transplantation: In-vitro and in-vivo studies

Energy Technology Data Exchange (ETDEWEB)

Rezapour-Lactoee, Alireza [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of); Yeganeh, Hamid, E-mail: h.yeganeh@ippi.ac.ir [Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Ostad, Seyed Nasser, E-mail: ostadnas@sina.tums.ac.ir [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, 16 Azar St, Enqelab Sq, Tehran 1417614411 (Iran, Islamic Republic of); Gharibi, Reza [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of); Mazaheri, Zohreh [Department of Anatomical Sciences, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ai, Jafar [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 14177-55469 Tehran (Iran, Islamic Republic of)

2016-12-01

Polyurethane/siloxane based wound dressing for transferring fibroblast cell sheet to wounded skin and ability to provide an optimum condition for cellular activity at damaged tissue was prepared in this research. The dressing was made thermoresponsive, via the introduction of a poly(N-isopropyl acrylamide) copolymer into the backbone of dressing. The ability of membrane for adhesion, growth, and proliferation of fibroblast cells was improved via surface modification with gelatin. The optimized dressing exhibited appropriate tensile strength (4.5 MPa) and elongation at break (80%) to protect wound against physical forces. Due to controlled equilibrium water absorption of about 89% and water vapor transmission rate of 2040 g/m{sup 2} day, the dressing could maintain the favorable moist environment over moderate to high exuding wounds. The grown cell sheet on dressing membrane could easily roll up from the surface just with lowering the temperature. The in vivo study of the wound dressed with cell loaded membrane confirmed the accelerated healing and production of tissue with complete re-epithelization, enhanced vascularization, and increased collagen deposition on the damaged area. - Highlights: • Versatile polymerization procedure to prepare wound dressing membranes • Improved cytocompatibility to support growth and proliferation of seeded fibroblasts • Utilizing thermoresponsive characteristic to transfer cell sheet to damaged tissue • Excellent physicomechanical properties of dressings to protect wound bed • Excellent fluid handling to provide moist environment over wounded tissue.

The fabrication of nanocomposites via calcium phosphate formation on gelatin–chitosan network and the gelatin influence on the properties of biphasic composites

International Nuclear Information System (INIS)

Babaei, Zahra; Jahanshahi, Mohsen; Rabiee, Sayed Mahmood

2013-01-01

A novel biodegradable polymer–ceramic nanocomposite which consisted of gelatin (Gel), chitosan (CS), and calcium phosphate (CaP) nanoparticles was prepared based on in situ preparation method. The fabricated biocomposites were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscope with X-ray elemental analysis (SEM-EDX). The characterization results confirmed that the crystalline calcium phosphate nanoparticles were mineralized in polymeric matrix and the interaction between Ca2+ in calcium phosphate and functional groups in polymers molecular chains was formed. XRD result showed that in addition to hydroxyapatite (HA), Brushite (BR) and tricalcium phosphate (β-TCP) particles also were formed due to lack of complete penetration of the basic solution into the polymeric matrix. However, SEM image indicated that the polymeric matrix has the controlling role in the particle size of calcium phosphate. The size of particles in three component composites was about 100 nm while in two component composites proved to be more in μm size. TEM observation supported SEM results and showed that the three component composites have calcium phosphate nanoparticles. The elastic modulus and compressive strength of the composites were also improved by the employment of gelatin and chitosan together, which can make them more beneficial for surgical applications. - Highlights: ► A new type of calcium phosphate nanocomposites consisted chitosan and gelatin as polymeric matrix was obtained via in situ precipitation method. ► The formed particles into the polymeric matrix are hydroxyapatite, Brushite and β-tricalcium phosphate. ► The polymer concentration is a predominant factor for inhibiting nucleation and growth of calcium phosphate particles as the particles size was also decreased by increasing the amount of polymeric phase. ► The nano particles formed in three component composites and micro particles

Concentrations and trophic magnification of cyclic siloxanes in aquatic biota from the Western Basin of Lake Erie, Canada

International Nuclear Information System (INIS)

McGoldrick, Daryl J.; Chan, Cecilia; Drouillard, Ken G.; Keir, Michael J.; Clark, Mandi G.; Backus, Sean M.

2014-01-01

We examine the concentrations and food web biomagnification of three cyclic volatile methylsiloxanes (cVMS) octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) using aquatic biota collected from Lake Erie. Concentrations of cVMS in biota were within the range reported for other studies of cVMS in aquatic biota. Trophic magnification factors (TMF) were assessed in various food web configurations to investigate the effects of food web structure. TMF estimates were highly dependent on the inclusion/exclusion of the organisms occupying the highest and lowest trophic levels and were >1 for D4 and D5, indicating biomagnification, in only 1 of the 5 food web configurations investigated and were <1 in the remaining 4 food web configurations. TMF estimates for PCB180 were also dependant on food web configuration, but did not correspond with those obtained for cVMS materials. These differences may be attributed to environmental exposure and/or lipid partitioning differences between PCB180 and cVMS. -- Highlights: • We investigated trophic magnification of siloxanes in aquatic biota from Lake Erie. • Trophic magnification estimates were variable and sensitive to food web structure. • Lipid partitioning of siloxanes and PCBs differ and may contribute to variability. -- Biomagnification estimates for siloxanes in Lake Erie are sensitive to food web structure, contaminant exposure pathways, and lipid partitioning differences between PCBs and siloxanes

Silica Nanoparticles Functionalized with Zwitterionic Sulfobetaine Siloxane for Application as a Versatile Antifouling Coating System.

Science.gov (United States)

Knowles, Brianna R; Wagner, Pawel; Maclaughlin, Shane; Higgins, Michael J; Molino, Paul J

2017-06-07

The growing need to develop surfaces able to effectively resist biological fouling has resulted in the widespread investigation of nanomaterials with potential antifouling properties. However, the preparation of effective antifouling coatings is limited by the availability of reactive surface functional groups and our ability to carefully control and organize chemistries at a materials' interface. Here, we present two methods of preparing hydrophilic low-fouling surface coatings through reaction of silica-nanoparticle suspensions and predeposited silica-nanoparticle films with zwitterionic sulfobetaine (SB). Silica-nanoparticle suspensions were functionalized with SB across three pH conditions and deposited as thin films via a simple spin-coating process to generate hydrophilic antifouling coatings. In addition, coatings of predeposited silica nanoparticles were surface functionalized via exposure to zwitterionic solutions. Quartz crystal microgravimetry with dissipation monitoring was employed as a high throughput technique for monitoring and optimizing reaction to the silica-nanoparticle surfaces. Functionalization of nanoparticle films was rapid and could be achieved over a wide pH range and at low zwitterion concentrations. All functionalized particle surfaces presented a high degree of wettability and resulted in large reductions in adsorption of bovine serum albumin protein. Particle coatings also showed a reduction in adhesion of fungal spores (Epicoccum nigrum) and bacteria (Escherichia coli) by up to 87 and 96%, respectively. These results indicate the potential for functionalized nanosilicas to be further developed as versatile fouling-resistant coatings for widespread coating applications.

Preparation and characterization of natural polymers as stabilizer for magnetic nanoparticles by gamma irradiation

International Nuclear Information System (INIS)

Eid, M.

2012-01-01

A Highly stable and uniformly distributed magnetic nanoparticles have been obtained onto hydroxyethyl methacrylate (HEMA)-Agar- Fe 3 O 4 (HAF), and HEMA-Gelatin- Fe 3 O 4 (HGF) networks via gamma irradiation and loading technique. The swelling property of the prepared hydrogels in bidistilled water and different ph's was studied and the results showed that, the swelling percent of the plain hydrogel was found to be higher for all different compositions. The morphology and structure of the prepared hydrogels and dispersion of the magnetite nanoparticles in the hydrogel network were examined by Scanning electron microscopy (SEM) and Infrared spectroscopy (FT-IR). The particle size of the formed magnetite nanoparticles has been confirmed by Dynamic light scattering (DLS) and Transmission electron microscope (TEM), and it was found to be smaller in loading technique than irradiation technique. The HEMA-Gelatin-Fe 3 O 4 has higher particle size than HEMA-Agar-Fe 3 O 4 (HAF). Finally, the drug loading capacities of the magnetite nanoparticles and their releasing dependence on different ph were investigated with doxorubicin hydrochloride (DOX) as an anticancer drug model.

pH-Switch Nanoprecipitation of Polymeric Nanoparticles for Multimodal Cancer Targeting and Intracellular Triggered Delivery of Doxorubicin.

Science.gov (United States)

Herranz-Blanco, Bárbara; Shahbazi, Mohammad-Ali; Correia, Alexandra R; Balasubramanian, Vimalkumar; Kohout, Tomáš; Hirvonen, Jouni; Santos, Hélder A

2016-08-01

Theranostic nanoparticles are emerging as potent tools for noninvasive diagnosis, treatment, and monitoring of solid tumors. Herein, an advanced targeted and multistimuli responsive theranostic platform is presented for the intracellular triggered delivery of doxorubicin. The system consists of a polymeric-drug conjugate solid nanoparticle containing encapsulated superparamagnetic iron oxide nanoparticles (IO@PNP) and decorated with a tumor homing peptide, iRGD. The production of this nanosystem is based on a pH-switch nanoprecipitation method in organic-free solvents, making it ideal for biomedical applications. The nanosystem shows sufficient magnetization saturation for magnetically guided therapy along with reduced cytotoxicity and hemolytic effects. IO@PNP are largely internalized by endothelial and metastatic cancer cells and iRGD decorated IO@PNP moderately enhance their internalization into endothelial cells, while no enhancement is found for the metastatic cancer cells. Poly(ethylene glycol)-block-poly(histidine) with pH-responsive and proton-sponge properties promotes prompt lysosomal escape once the nanoparticles are endocyted. In addition, the polymer-doxorubicin conjugate solid nanoparticles show both intracellular lysosomal escape and efficient translocation of doxorubicin to the nuclei of the cells via cleavage of the amide bond. Overall, IO@PNP-doxorubicin and the iRGD decorated counterpart demonstrate to enhance the toxicity of doxorubicin in cancer cells by improving the intracellular delivery of the drug carried in the IO@PNP. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Particle size modeling and morphology study of chitosan/gelatin/nanohydroxyapatite nanocomposite microspheres for bone tissue engineering.

Science.gov (United States)

Bagheri-Khoulenjani, Shadab; Mirzadeh, Hamid; Etrati-Khosroshahi, Mohammad; Shokrgozar, Mohammad Ali

2013-06-01

In this study, nanocomposite microspheres based on chitosan/gelatin/nanohydroxyapatite were fabricated, and effects of the nanohydroxyapatite/biopolymer (chitosan/gelatin) weight ratio (nHA/P), stirring rate, chitosan concentration and biopolymer concentration on the particle size, and morphology of nanocomposite microspheres were investigated. Particle size of microspheres was modeled by design of experiments using the surface response method. Particle size, morphology of microspheres, and distribution of nanoparticles within the composite microspheres were evaluated using an optical microscope, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. X-ray diffraction and Fourier transform infrared spectroscopy were applied to study the physical and chemical characteristics of microspheres. Results showed that by modulating the nHA/P ratio, chitosan concentration, polymer concentration, and stirring rate, it is possible to fabricate microspheres in wide rages of particle size (5-150 μm). Analysis of variance confirmed that the modified quadratic model can be used to predict the particle size of nanocomposite microspheres within the design space. SEM studies showed that microspheres with different compositions had totally different morphologies from dense morphologies to porous ones. TEM images demonstrated that nanoparticles were distributed uniformly within the polymeric matrix. MTT assay and cell culture studies showed that microspheres with different compositions possessed good biocompatibility. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. Copyright © 2012 Wiley Periodicals, Inc.

Bacterial Community Analysis, New Exoelectrogen Isolation and Enhanced Performance of Microbial Electrochemical Systems Using Nano-Decorated Anodes

Science.gov (United States)

Xu, Shoutao

. Citrobacter strain SX-1 is capable of generating electricity from a wide range of substrates in MFCs. This finding increases the known diversity of power generating exoelectrogens and provids a new strain to explore the mechanisms of extracellular electron transfer from bacteria to electrode. The wide range of substrate utilization by SX-1 increases the application potential of MFCs in renewable energy generation and waste treatment. Anode properties are critical for the performance of microbial electrolysis cells (MECs). Inexpensive Fe nanoparticle modified graphite disks were used as anodes to preliminarily investigate the effects of nanoparticles on the performance of Shewanella oneidensis MR-1 in MECs. Results demonstrated that average current densities produced with Fe nanoparticle decorated anodes were up to 5.9-fold higher than plain graphite anodes. Whole genome microarray analysis of the gene expression showed that genes encoding biofilm formation were significantly up-regulated as a response to nanoparticle decorated anodes. Increased expression of genes related to nanowires, flavins and c-type cytochromes indicate that enhanced mechanisms of electron transfer to the anode may also have contributed to the observed increases in current density. The majority of the remaining differentially expressed genes were associated with electron transport and anaerobic metabolism demonstrating a systemic response to increased power loads. The carbon nanotube (CNT) is another form of nano materials. Carbon nanotube (CNT) modified graphite disks were used as anodes to investigate the effects of nanostructures on the performance S. oneidensis MR-1 in microbial electrolysis cells (MECs). The current densities produced with CNT decorated anodes were up to 5.6-fold higher than plain graphite anodes. Global transcriptome analysis showed that cytochrome c genes associated with extracellular electron transfer are up-expressed by CNT decorated anodes, which is the leading factor to

The physico-chemical properties of pangas catfish (Pangasius pangasius) skin gelatin

Science.gov (United States)

Pradarameswari, K. A.; Zaelani, K.; Waluyo, E.; Nurdiani, R.

2018-04-01

Gelatin can be used as emulsifier and stabilizer in food products. Until now, the most widely used raw materials for the production of gelatin industry are cow bone, cow skin and pig skin. Fish gelatin has been highlighted as a better alternative to replace mammals gelatin based on ethical and religious perspective. Fish gelatin was extracted from Pangas catfish skin to determine its physico-chemical properties. Different temperatures (45 °C, 50 °C, 55 °C) were employed during gelatin extraction. Higher temperature increased the yield and fat contents of Pangas catfish skin gelatin. In contrary, higher water, protein, ash contents were observed during lower temperature. Temperature significantly (p fish skin gelatin. Based on the FTIR spectrum catfish skin gelatin functional groups can be identified as N-H, O-H, C = H, C-O and C-H.

Design and analysis of siloxanes removal by adsorption from landfill gas for waste-to-energy processes.

Science.gov (United States)

Elwell, Anthony C; Elsayed, Nada H; Kuhn, John N; Joseph, Babu

2018-03-01

Separation of volatile methyl siloxanes from landfill gas using fixed adsorption beds was modeled with the objective of identifying appropriate technology and the economics associated with this purification step. A general adsorption model assuming plug flow and radial symmetry was developed and used to conduct a parametric sweep of 162 unique cases. The varied parameters were adsorbent type (activated carbon and silica gel), bed height (3.05-9.15 m/10-30 ft), inlet siloxane concentration (5-15 mg/m 3 ), moisture content (0-100% relative humidity at STP or RH), and siloxane tolerance limit (0.094-9.4 mg/m 3 ) that correlated to three distinct energy conversion technologies (electricity production using engines or fuels cells or catalytic conversion to liquid hydrocarbon fuels). Due to the detrimental effect of RH on siloxane absorption, the maximum allowable moisture content of LFG before purification is 50% RH and moisture removal processes are also required. The design calculations using a selected case study show that the adsorption bed height required needed for 6 months minimum breakthrough time for catalytic fuel production is twice that for engine applications. Fuel cell applications require 3 times the bed height compared to engine applications. However, the purification costs amounted to 94%, 16% and 52% of recovered product value for engine, liquefaction, and fuel cell applications, respectively indicating the need for a high value product to justify purification costs. The approaches and conclusions can be extended to specific process conditions for landfill gas purification and to other processes that use biogas produced from waste as a feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

Female versus male biological identities of nanoparticles determine the interaction with immune cells in fish

DEFF Research Database (Denmark)

Hayashi, Yuya; Miclaus, Teodora; Murugadoss, Sivakumar

2017-01-01

Biomolecule decoration of nanoparticles provides a corona that modulates how the nanoparticles interact with biological milieus. The corona composition has proved to reflect the differences in the repertoire of proteins to which the nanoparticles are exposed, and as a result the same nanoparticles...... and myeloid populations of the blood cells preferentially accumulated the nanoparticles with a female biological identity, irrespective of the sex of the fish from which the cells were obtained. The concept of repertoire differences in the corona proteome therefore deserves further attention, as various...

Preparation and characterization of hydroxyapatite/gelatin composite membranes for immunoisolation

International Nuclear Information System (INIS)

Chen, Jyh-Ping; Chang, Feng-Nian

2012-01-01

Highlights: ► Cross-linking gelatin in the presence of hydroxyapatite forms composite membranes. ► The membrane was used for immunoisolation and encapsulation of cells. ► Encapsulated islet cells secrete insulin in response to glucose concentrations. ► The membrane is a good candidate for bioartificial pancreas development. - Abstract: Composite membranes are fabricated from hydroxyapatite (HAP) and gelatin for immunoisolation of cells. The films were fabricated by crosslinking 5 wt%, 10 wt%, and 20 wt% gelatin with 1 wt% glutaraldehyde (GA) in the presence of HAP. Fourier transform infrared spectroscopy analysis confirms imide bond formation between GA and gelatin, while the crystal structure of HAP powder remains unchanged from X-ray diffraction analysis. The degree of crosslinking depends on crosslinking time and gelatin concentration. For 5% and 10% gelatin, the degree of crosslinking levels off at 90% within 48 h. From scanning electron microscopy micrographs, the microstructure of the composite membrane depends on the amount of gelatin used in the crosslinking reaction. The mechanical strength of the composite membrane could be enhanced by increasing the gelatin concentration. BET analysis indicates that pore size of the micropores on the surface HAP/gelatin agglomerates decreases with increasing gelatin concentration. However, the macropore, through which diffusion of molecules occurs, is larger at higher gelatin concentrations. The permeability coefficients of different molecules through a HAP/gelatin composite membrane increase with increasing gelatin concentration and is inversely correlated with the molecular weight of the molecule. For immunoisolation of cells, the diffusion of large molecules stimulated by the immune system can be rejected by a chamber constructed from the HAP/gelatin membrane. Insulinoma cells were encapsulated in alginate-poly-L-lysine-alginate microcapsules and enclosed in a HAP/gelatin chamber. The chamber did not impair

Preparation and characterization of hydroxyapatite/gelatin composite membranes for immunoisolation

Energy Technology Data Exchange (ETDEWEB)

Chen, Jyh-Ping, E-mail: jpchen@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, 259 Wen Hwa 1st Rd., Kwei-San, Taoyuan 333, Taiwan (China); Chang, Feng-Nian [Department of Chemical and Materials Engineering, Chang Gung University, 259 Wen Hwa 1st Rd., Kwei-San, Taoyuan 333, Taiwan (China)

2012-12-01

Highlights: Black-Right-Pointing-Pointer Cross-linking gelatin in the presence of hydroxyapatite forms composite membranes. Black-Right-Pointing-Pointer The membrane was used for immunoisolation and encapsulation of cells. Black-Right-Pointing-Pointer Encapsulated islet cells secrete insulin in response to glucose concentrations. Black-Right-Pointing-Pointer The membrane is a good candidate for bioartificial pancreas development. - Abstract: Composite membranes are fabricated from hydroxyapatite (HAP) and gelatin for immunoisolation of cells. The films were fabricated by crosslinking 5 wt%, 10 wt%, and 20 wt% gelatin with 1 wt% glutaraldehyde (GA) in the presence of HAP. Fourier transform infrared spectroscopy analysis confirms imide bond formation between GA and gelatin, while the crystal structure of HAP powder remains unchanged from X-ray diffraction analysis. The degree of crosslinking depends on crosslinking time and gelatin concentration. For 5% and 10% gelatin, the degree of crosslinking levels off at 90% within 48 h. From scanning electron microscopy micrographs, the microstructure of the composite membrane depends on the amount of gelatin used in the crosslinking reaction. The mechanical strength of the composite membrane could be enhanced by increasing the gelatin concentration. BET analysis indicates that pore size of the micropores on the surface HAP/gelatin agglomerates decreases with increasing gelatin concentration. However, the macropore, through which diffusion of molecules occurs, is larger at higher gelatin concentrations. The permeability coefficients of different molecules through a HAP/gelatin composite membrane increase with increasing gelatin concentration and is inversely correlated with the molecular weight of the molecule. For immunoisolation of cells, the diffusion of large molecules stimulated by the immune system can be rejected by a chamber constructed from the HAP/gelatin membrane. Insulinoma cells were encapsulated in alginate

Experimental Characterization and Hygroscopicity Determination of Secondary Aerosol from D5 Cyclic Siloxane Oxidation

Science.gov (United States)

Stanier, C. O.; Janechek, N. J.; Bryngelson, N.; Marek, R. F.; Lersch, T.; Bunker, K.; Casuccio, G.; Brune, W. H.; Hornbuckle, K. C.

2017-12-01

Cyclic volatile methyl siloxanes are anthropogenic chemicals present in personal care products such as antiperspirants and lotions. These are volatile chemicals that are readily released into the atmosphere by product use. Due to their emission and relatively slow kinetics of their major transformation pathway, reaction with hydroxyl radicals (OH), these compounds are present in high concentrations in indoor environments and widespread in outdoor environments. Cyclic siloxane reaction with OH can lead to secondary organic aerosols, and due to the widespread prevalence of the parent compounds, may be an important source of ambient aerosols. Atmospheric aerosols have important influences to the climate by affecting the radiative balance and by serving as cloud condensation nuclei (CCN) which influence clouds. While the parent compounds have been well-studied, the oxidation products have received much less attention, with almost no ambient measurements or experimental physical property data. We report physical properties of aerosols generated by reacting the cyclic siloxane D5 with OH using a Potential Aerosol Mass (PAM) photochemical chamber. The particles were characterized by SMPS, imaging and elemental analysis using both Transmission Electron Microscopy and Scanning Transmission Electron Microscopy equipped with Energy Dispersive X-ray Spectroscopy systems (TEM-EDS and STEM-EDS), volatility measurements using Volatility Tandem Differential Mobility Analyzer (V-TDMA), and hygroscopicity measurements to determine CCN potential using a Droplet Measurement Technologies Cloud Condensation Nuclei Counter (DMT-CCN). Aerosol yield sensitivity to D5 and OH concentrations, residence time, and seed aerosols were analyzed. TEM-EDS and STEM-EDS analysis show spherical particle morphology with elemental composition consistent with aerosols derived from cyclic siloxane sources. Measured aerosol yields were 20-50% with typical aerosol concentrations 300,000 particles cm-3, up to