WorldWideScience

Sample records for surface immobilized factors

  1. Immobilization of epidermal growth factor on titanium and stainless steel surfaces via dopamine treatment

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    Kang, Jeonghwa [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397 Japan (Japan); Sakuragi, Makoto; Shibata, Aya; Abe, Hiroshi; Kitajima, Takashi; Tada, Seiichi [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Mizutani, Masayoshi; Ohmori, Hitoshi [Material Fabrication Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Ayame, Hirohito [Diagnostic Biochip Laboratory, RIKEN Center for Intellectual Property Strategies, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Son, Tae Il [Bioscience and Biotechnology, Chung-Ang University, 40-1 San, Nae-Ri, Daeduck-myun, Ansung-si, Kyungki-do, 456-756 (Korea, Republic of); Aigaki, Toshiro [Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397 Japan (Japan); Ito, Yoshihiro, E-mail: y-ito@riken.jp [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397 Japan (Japan); Diagnostic Biochip Laboratory, RIKEN Center for Intellectual Property Strategies, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan)

    2012-12-01

    Titanium and stainless steel were modified with dopamine for the immobilization of biomolecules, epidermal growth factor (EGF). First, the treatment of metal surfaces with a dopamine solution under different pH conditions was investigated. At higher pH, the dopamine solution turned brown and formed precipitates. Treatment of the metals with dopamine at pH 8.5 also resulted in the development of brown color at the surface of the metals. The hydrophobicity of the surfaces increased after treatment with dopamine, independently of pH. X-ray photoelectron spectroscopy revealed the formation of a significant amount of an organic layer on both surfaces at pH 8.5. According to ellipsometry measurements, the organic layer formed at pH 8.5 was about 1000 times as thick as that formed at pH 4.5. The amount of amino groups in the layer formed at pH 8.5 was also higher than that observed in the layer formed at pH 4.5. EGF molecules were immobilized onto the dopamine-treated surfaces via a coupling reaction using carbodiimide. A greater amount of EGF was immobilized on surfaces treated at pH 8.5 compared with pH 4.5. Significantly higher growth of rat fibroblast cells was observed on the two EGF-immobilized surfaces compared with non-immobilized surfaces in the presence of EGF. The present study demonstrated that metals can become bioactive via the surface immobilization of a growth factor and that the effect of the immobilized growth factor on metals was greater than that of soluble growth factor. - Highlights: Black-Right-Pointing-Pointer Epidermal growth factor was covalently immobilized on titan or stainless steel surfaces. Black-Right-Pointing-Pointer Amino groups were formed on the surfaces by the treatment and the growth factor was immobilized through amide bonds. Black-Right-Pointing-Pointer The immobilized epidermal growth factor accelerated cell proliferation more than soluble ones on the surfaces.

  2. Surface cell immobilization within perfluoroalkoxy microchannels

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    Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

    2014-11-30

    Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor{sup ®} and Topas{sup ®}.

  3. The creation of an antithrombotic surface by apyrase immobilization

    Science.gov (United States)

    Nilsson, Per H; Engberg, Anna E; Bäck, Jennie; Faxälv, Lars; Lindahl, Tomas L.; Nilsson, Bo; Ekdahl, Kristina Nilsson

    2010-01-01

    Blood incompatibility reactions caused by surfaces often involve platelet activation and subsequent platelet-initiated activation of the coagulation and complement cascades. The goal of this study was to immobilize apyrase on a biomaterial surface in order to develop an enzymatically active surface that would have the capacity to inhibit platelet activation by degrading ADP. We were able to immobilize apyrase on a polystyrene surface with preservation of the enzymatic activity. We then analyzed the hemocompatibility of the apyrase surface and of control surfaces by incubation with platelet-rich plasma (PRP) or whole blood. Monitoring of markers of platelet, coagulation, and complement activation and staining of the surfaces revealed decreased levels of platelet and coagulation activation parameters on the apyrase surface. The formation of antithrombin-thrombin and antithrombin-factor XIa complexes and the extent of platelet consumption were significantly lower on the apyrase surface than on any of the control surfaces. No significant differences were seen in complement activation (C3a levels). Staining of the apyrase surface revealed low platelet adherence and no formation of granulocyte-platelet complexes. These results demonstrate that it is possible to create an anti-thrombotic surface targeting the ADP amplification of platelet activation by immobilizing apyrase. PMID:20211488

  4. Effect of photo-immobilization of epidermal growth factor on the cellular behaviors

    International Nuclear Information System (INIS)

    Ogiwara, Kazutaka; Nagaoka, Masato; Cho, Chong-Su; Akaike, Toshihiro

    2006-01-01

    We constructed photo-reactive epidermal growth factor (EGF) bearing p-azido phenylalanine at the C-terminal (HEGFP) by genetic engineering to investigate the possibility of immobilized EGF as a novel artificial extracellular matrix (ECM). The constructed recombinant protein was immobilized to glass surface by ultraviolet irradiation. A431 cells adhered both to HEGFP-immobilized and collagen-coated surfaces. Interaction between immobilized HEGFP and EGF receptors in the A431 cells was independent of Mg 2+ although integrin-mediated cell adhesion to natural ECMs is dependent on Mg 2+ . Phosphorylation of EGF receptors in A431 cells was induced by immobilized HEGFP as same as soluble EGF. DNA uptake of hepatocytes decreased by immobilized HEGFP whereas it increased by soluble EGF. Liver-specific functions of hepatocytes were maintained for 3 days by immobilized HEGFP whereas they were not maintained by soluble EGF, indicating that immobilized HEGFP follows different signal transduction pathway from soluble EGF

  5. Bed Rest and Immobilization: Risk Factors for Bone Loss

    Science.gov (United States)

    ... Risk Factors for Bone Loss Bed Rest and Immobilization: Risk Factors for Bone Loss Like muscle, bone ... complications of pregnancy; and those who are experiencing immobilization of some part of the body because of ...

  6. Drop drying on surfaces determines chemical reactivity - the specific case of immobilization of oligonucleotides on microarrays

    Science.gov (United States)

    2013-01-01

    Background Drop drying is a key factor in a wide range of technical applications, including spotted microarrays. The applied nL liquid volume provides specific reaction conditions for the immobilization of probe molecules to a chemically modified surface. Results We investigated the influence of nL and μL liquid drop volumes on the process of probe immobilization and compare the results obtained to the situation in liquid solution. In our data, we observe a strong relationship between drop drying effects on immobilization and surface chemistry. In this work, we present results on the immobilization of dye labeled 20mer oligonucleotides with and without an activating 5′-aminoheptyl linker onto a 2D epoxysilane and a 3D NHS activated hydrogel surface. Conclusions Our experiments identified two basic processes determining immobilization. First, the rate of drop drying that depends on the drop volume and the ambient relative humidity. Oligonucleotides in a dried spot react unspecifically with the surface and long reaction times are needed. 3D hydrogel surfaces allow for immobilization in a liquid environment under diffusive conditions. Here, oligonucleotide immobilization is much faster and a specific reaction with the reactive linker group is observed. Second, the effect of increasing probe concentration as a result of drop drying. On a 3D hydrogel, the increasing concentration of probe molecules in nL spotting volumes accelerates immobilization dramatically. In case of μL volumes, immobilization depends on whether the drop is allowed to dry completely. At non-drying conditions, very limited immobilization is observed due to the low oligonucleotide concentration used in microarray spotting solutions. The results of our study provide a general guideline for microarray assay development. They allow for the initial definition and further optimization of reaction conditions for the immobilization of oligonucleotides and other probe molecule classes to different

  7. An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

    Science.gov (United States)

    Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

    2015-01-01

    The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

  8. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    International Nuclear Information System (INIS)

    Lonergan, N.E.; Britt, L.D.; Sullivan, C.J.

    2014-01-01

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg 2+ and Ca 2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while

  9. A new route for chitosan immobilization onto polyethylene surface

    Czech Academy of Sciences Publication Activity Database

    Popelka, A.; Novák, I.; Lehocký, M.; Junkar, I.; Mozetič, M.; Kleinová, A.; Janigová, I.; Šlouf, Miroslav; Bílek, F.; Chodák, I.

    2012-01-01

    Roč. 90, č. 4 (2012), s. 1501-1508 ISSN 0144-8617 Institutional support: RVO:61389013 Keywords : immobilization * plasma treatment * chitosan Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.479, year: 2012

  10. Optimization of Phospholipase A1 Immobilization on Plasma Surface Modified Chitosan Nanofibrous Mat

    Directory of Open Access Journals (Sweden)

    Zahra Beig Mohammadi

    2016-01-01

    Full Text Available Phospholipase A1 is known as an effective catalyst for hydrolysis of various phospholipids in enzymatic vegetable oil degumming. Immobilization is one of the most efficient strategies to improve its activity, recovery and functional properties. In this study, chitosan-co-polyethylene oxide (90:10 nanofibrous mat was successfully fabricated and modified with atmospheric plasma at different times (2, 6 and 10 min to interact with enzyme molecules. Scanning electron microscopy images revealed that the membranes retained uniform nanofibrous and open porous structures before and after the treatment. PLA1 was successfully immobilized onto the membrane surfaces via covalent bonds with the functional groups of chitosan nanofibrous mat. Response surface methodology was used to optimize the immobilization conditions for reaching the maximum immobilization efficiency. Enzyme concentration, pH, and immobilization time were found to be significant key factors. Under optimum conditions (5.03 h, pH 5.63, and enzyme dosage 654.36 UI, the atmospheric plasma surface modified chitosan nanofibers reached the highest immobilization efficiency (78.50%. Fourier transform infrared spectroscopy of the control and plasma surface-modified chitosan nanofibers revealed the functional groups of nanofibers and their reaction with the enzyme. The results indicated that surface modification by atmospheric plasma induced an increase in PLA1 loading on the membrane surfaces.

  11. In situ ellipsometric study of surface immobilization of flagellar filaments

    Energy Technology Data Exchange (ETDEWEB)

    Kurunczi, S., E-mail: kurunczi@mfa.kfki.hu [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Nemeth, A.; Huelber, T. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Kozma, P. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Petrik, P. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Jankovics, H. [Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Sebestyen, A. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Vonderviszt, F. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Institute of Enzymology, Karolina ut 29-33, Budapest, H-1113 (Hungary); and others

    2010-10-15

    Protein filaments composed of thousands of subunits are promising candidates as sensing elements in biosensors. In this work in situ spectroscopic ellipsometry is applied to monitor the surface immobilization of flagellar filaments. This study is the first step towards the development of layers of filamentous receptors for sensor applications. Surface activation is performed using silanization and a subsequent glutaraldehyde crosslinking. Structure of the flagellar filament layers immobilized on activated and non-activated Si wafer substrates is determined using a two-layer effective medium model that accounted for the vertical density distribution of flagellar filaments with lengths of 300-1500 nm bound to the surface. The formation of the first interface layer can be explained by the multipoint covalent attachment of the filaments, while the second layer is mainly composed of tail pinned filaments floating upwards with the free parts. As confirmed by atomic force microscopy, covalent immobilization resulted in an increased surface density compared to absorption.

  12. Gelatin Functionalization of Biomaterial Surfaces: Strategies for Immobilization and Visualization

    Directory of Open Access Journals (Sweden)

    Peter Dubruel

    2011-01-01

    Full Text Available In the present work, the immobilization of gelatin as biopolymer on two types of implantable biomaterials, polyimide and titanium, was compared. Both materials are known for their biocompatibility while lacking cell-interactive behavior. For both materials, a pre-functionalization step was required to enable gelatin immobilization. For the polyimide foils, a reactive succinimidyl ester was introduced first on the surface, followed by covalent grafting of gelatin. For the titanium material, methacrylate groups were first introduced on the Ti surface through a silanization reaction. The applied functionalities enabled the subsequent immobilization of methacrylamide modified gelatin. Both surface modified materials were characterized in depth using atomic force microscopy, static contact angle measurements, confocal fluorescence microscopy, attenuated total reflection infrared spectroscopy and X-ray photo-electron spectroscopy. The results indicated that the strategies elaborated for both material classes are suitable to apply stable gelatin coatings. Interestingly, depending on the material class studied, not all surface analysis techniques are applicable.

  13. Immobilized enzymes: understanding enzyme - surface interactions at the molecular level.

    Science.gov (United States)

    Hoarau, Marie; Badieyan, Somayesadat; Marsh, E Neil G

    2017-11-22

    Enzymes immobilized on solid supports have important and industrial and medical applications. However, their uses are limited by the significant reductions in activity and stability that often accompany the immobilization process. Here we review recent advances in our understanding of the molecular level interactions between proteins and supporting surfaces that contribute to changes in stability and activity. This understanding has been facilitated by the application of various surface-sensitive spectroscopic techniques that allow the structure and orientation of enzymes at the solid/liquid interface to be probed, often with monolayer sensitivity. An appreciation of the molecular interactions between enzyme and surface support has allowed the surface chemistry and method of enzyme attachement to be fine-tuned such that activity and stability can be greatly enhanced. These advances suggest that a much wider variety of enzymes may eventually be amenable to immobilization as green catalysts.

  14. Investigating the dynamics of surface-immobilized DNA nanomachines

    Science.gov (United States)

    Dunn, Katherine E.; Trefzer, Martin A.; Johnson, Steven; Tyrrell, Andy M.

    2016-07-01

    Surface-immobilization of molecules can have a profound influence on their structure, function and dynamics. Toehold-mediated strand displacement is often used in solution to drive synthetic nanomachines made from DNA, but the effects of surface-immobilization on the mechanism and kinetics of this reaction have not yet been fully elucidated. Here we show that the kinetics of strand displacement in surface-immobilized nanomachines are significantly different to those of the solution phase reaction, and we attribute this to the effects of intermolecular interactions within the DNA layer. We demonstrate that the dynamics of strand displacement can be manipulated by changing strand length, concentration and G/C content. By inserting mismatched bases it is also possible to tune the rates of the constituent displacement processes (toehold-binding and branch migration) independently, and information can be encoded in the time-dependence of the overall reaction. Our findings will facilitate the rational design of surface-immobilized dynamic DNA nanomachines, including computing devices and track-based motors.

  15. Bioremediation of contaminated surface water by immobilized Micrococcus roseus.

    Science.gov (United States)

    Li, H; Li, P; Hua, T; Zhang, Y; Xiong, X; Gong, Z

    2005-08-01

    The problems caused by contaminated surface water have gradually become more serious in recent years. Although various remediation technologies were investigated, unfortunately, no efficient method was developed. In this paper, a new bioremediation technology was studied using Micrococcus roseus, which was immobilized in porous spherical beads by an improved polyvinyl alcohol (PVA) - sodium alginate (SA) embedding method. The experimental results indicated that COD removal rate could reach 64.7 % within 72 hours when immobilized M. roseus beads were used, which was ten times as high as that of free cells. The optimum inoculation rate of immobilized M. roseus beads was 10 % (mass percent of the beads in water sample, g g(-1)). Suitable aeration was proved necessary to enhance the bioremediation process. The immobilized cells had an excellent tolerance to pH and temperature changes, and were also more resistant to heavy metal stress compared with free cells. The immobilized M. roseus beads had an excellent regeneration capacity and could be reused after 180-day continuous usage. The Scanning Electronic Microscope (SEM) analysis showed that the bead microstructure was suitable for M. roseus growth, however, some defect structures should still be improved.

  16. Self-assembling peptide hydrogels immobilized on silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Franchi, Stefano; Battocchio, Chiara; Galluzzi, Martina; Navisse, Emanuele [Department of Sciences, University “Roma Tre”, Via della Vasca Navale 79, Roma, 00146 (Italy); Zamuner, Annj; Dettin, Monica [Department of Industrial Engineering, University of Padua, Via Marzolo, 9, Padua, 35131 (Italy); Iucci, Giovanna, E-mail: giovanna.iucci@uniroma3.it [Department of Sciences, University “Roma Tre”, Via della Vasca Navale 79, Roma, 00146 (Italy)

    2016-12-01

    The hydrogels of self-assembling ionic complementary peptides have collected in the scientific community increasing consensus as mimetics of the extracellular matrix that can offer 3D supports for cell growth or be vehicles for the delivery of stem cells or drugs. Such scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In this context, our research deals with the introduction of a layer of self-assembling peptides on a silicon surface by covalent anchoring and subsequent physisorption. In this work, we present a spectroscopic investigation of the proposed bioactive scaffolds, carried out by surface-sensitive spectroscopic techniques such as XPS (X-ray photoelectron spectroscopy) and RAIRS (Reflection Absorption Infrared Spectroscopy) and by state-of-the-art synchrotron radiation methodologies such as angle dependent NEXAFS (Near Edge X-ray Absorption Fine Structure). XPS studies confirmed the change in the surface composition in agreement with the proposed enrichments, and led to assess the self-assembling peptide chemical stability. NEXAFS spectra, collected in angular dependent mode at the N K-edge, allowed to investigate the self-assembling behavior of the macromolecules, as well as to determine their molecular orientation on the substrate. Furthermore, Infrared Spectroscopy measurements demonstrated that the peptide maintains its secondary structure (β-sheet anti-parallel) after deposition on the silicon surface. The complementary information acquired by means of XPS, NEXAFS and RAIRS lead to hypothesize a “layer-by-layer” arrangement of the immobilized peptides, giving rise to an ordered 3D nanostructure. - Highlights: • A self-assembling peptide (SAP) was covalently immobilized of on a flat silicon surface. • A physisorbed SAP layer was grown on top of the covalently immobilized peptide layer. • Molecular order and orientation of the peptide overlayer on the flat silicon

  17. Self-assembling peptide hydrogels immobilized on silicon surfaces

    International Nuclear Information System (INIS)

    Franchi, Stefano; Battocchio, Chiara; Galluzzi, Martina; Navisse, Emanuele; Zamuner, Annj; Dettin, Monica; Iucci, Giovanna

    2016-01-01

    The hydrogels of self-assembling ionic complementary peptides have collected in the scientific community increasing consensus as mimetics of the extracellular matrix that can offer 3D supports for cell growth or be vehicles for the delivery of stem cells or drugs. Such scaffolds have also been proposed as bone substitutes for small defects as they promote beneficial effects on human osteoblasts. In this context, our research deals with the introduction of a layer of self-assembling peptides on a silicon surface by covalent anchoring and subsequent physisorption. In this work, we present a spectroscopic investigation of the proposed bioactive scaffolds, carried out by surface-sensitive spectroscopic techniques such as XPS (X-ray photoelectron spectroscopy) and RAIRS (Reflection Absorption Infrared Spectroscopy) and by state-of-the-art synchrotron radiation methodologies such as angle dependent NEXAFS (Near Edge X-ray Absorption Fine Structure). XPS studies confirmed the change in the surface composition in agreement with the proposed enrichments, and led to assess the self-assembling peptide chemical stability. NEXAFS spectra, collected in angular dependent mode at the N K-edge, allowed to investigate the self-assembling behavior of the macromolecules, as well as to determine their molecular orientation on the substrate. Furthermore, Infrared Spectroscopy measurements demonstrated that the peptide maintains its secondary structure (β-sheet anti-parallel) after deposition on the silicon surface. The complementary information acquired by means of XPS, NEXAFS and RAIRS lead to hypothesize a “layer-by-layer” arrangement of the immobilized peptides, giving rise to an ordered 3D nanostructure. - Highlights: • A self-assembling peptide (SAP) was covalently immobilized of on a flat silicon surface. • A physisorbed SAP layer was grown on top of the covalently immobilized peptide layer. • Molecular order and orientation of the peptide overlayer on the flat silicon

  18. High Efficiency Acetylcholinesterase Immobilization on DNA Aptamer Modified Surfaces

    Directory of Open Access Journals (Sweden)

    Orada Chumphukam

    2014-04-01

    Full Text Available We report here the in vitro selection of DNA aptamers for electric eel acetylcholinesterase (AChE. One selected aptamer sequence (R15/19 has a high affinity towards the enzyme (Kd = 157 ± 42 pM. Characterization of the aptamer showed its binding is not affected by low ionic strength (~20 mM, however significant reduction in affinity occurred at high ionic strength (~1.2 M. In addition, this aptamer does not inhibit the catalytic activity of AChE that we exploit through immobilization of the DNA on a streptavidin-coated surface. Subsequent immobilization of AChE by the aptamer results in a 4-fold higher catalytic activity when compared to adsorption directly on to plastic.

  19. Immobilization of β-galactosidase from Kluyveromyces lactis onto polymeric membrane surfaces: effect of surface characteristics.

    Science.gov (United States)

    Güleç, Hacı Ali

    2013-04-01

    The aim of this study was to investigate the effects of surface characteristics of plain and plasma modified cellulose acetate (CA) membranes on the immobilization yield of β-galactosidases from Kluyveromyces lactis (KLG) and its galacto-oligosaccharide (GOS) yield, respectively. Low pressure plasma treatments involving oxygen plasma activation, plasma polymerization (PlsP) of ethylenediamine (EDA) and PlsP of 2-mercaptoethanol were used to modify plain CA membrane surfaces. KLG enzyme was immobilized onto plain and oxygen plasma treated membrane surfaces by simple adsorption. Oxygen plasma activation increased the hydrophylicity of CA membrane surfaces and it improved the immobilization yield of the enzyme by 42%. KLG enzyme was also immobilized onto CA membrane surfaces through amino groups created by PlsP of EDA via covalent binding. Plasma action at 60W plasma power and 15 min. exposure time improved the amount of membrane bounded enzyme by 3.5-fold. The enrichment of the amount of amino groups via polyethyleneimine (PEI) addition enhanced this increase from 3.5-fold to 4.5-fold. Although high enzyme loading was achived (65-83%), both of the methods dramatically decreased the enzyme activity (11-12%) and GOS yield due to probably negative effects of active amino groups. KLG enzyme was more effectively immobilized onto thiolated CA membrane surface created by PlsP of 2-mercaptoethanol with high immobilization yield (70%) and especially high enzyme activity (46%). Immobilized enzymes on the CA membranes treated by PlsP were successively reutilized for 5-8 cycles at 25°C and enzymatic derivatives retained approximately 75-80% of their initial activites at the end of the reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Influence of cosolvents on the hydrophobic surface immobilization topography of Candida antarctica lipase B

    Science.gov (United States)

    The presence of cosolvents and co-solutes during the immobilization of lipases on hydrophobic supports may influence the extent of lipase immobilization and the long-term catalytic stability of the biocatalyst. Candida antarctica B lipase immobilization was examined on a hydrophobic surface, i.e., ...

  1. Electrochemical immobilization of biomolecules on gold surface modified with monolayered L-cysteine

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Mitsunori, E-mail: honda.mitsunori@jaea.go.jp; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie

    2014-04-01

    Immobilization of organic molecules on the top of a metal surface is not easy because of lattice mismatch between organic and metal crystals. Gold atoms bind to thiol groups through strong chemical bonds, and a self-assembled monolayer of sulfur-terminated organic molecules is formed on the gold surface. Herein, we suggested that a monolayer of L-cysteine deposited on a gold surface can act as a buffer layer to immobilize biomolecules on the metal surface. We selected lactic acid as the immobilized biomolecule because it is one of the simplest carboxyl-containing biomolecules. The immobilization of lactic acid on the metal surface was carried out by an electrochemical method in an aqueous environment under the potential range varying from − 0.6 to + 0.8 V. The surface chemical states before and after the electrochemical reaction were characterized using X-ray photoelectron spectroscopy (XPS). The N 1s and C 1s XPS spectra showed that the L-cysteine-modified gold surface can immobilize lactic acid via peptide bonds. This technique might enable the immobilization of large organic molecules and biomolecules. - Highlights: • Monolayer l-cysteine deposited on Au surface as a buffer layer to immobilize biomolecules. • Lactic acid as the immobilized biomolecule as it is simple carboxyl-containing biomolecule. • X-ray photoelectron spectroscopy (XPS) of surface chemical states, before and after. • L-cysteine-modified Au surface can immobilize lactic acid via peptide bonds.

  2. Electrochemical immobilization of biomolecules on gold surface modified with monolayered L-cysteine

    International Nuclear Information System (INIS)

    Honda, Mitsunori; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie

    2014-01-01

    Immobilization of organic molecules on the top of a metal surface is not easy because of lattice mismatch between organic and metal crystals. Gold atoms bind to thiol groups through strong chemical bonds, and a self-assembled monolayer of sulfur-terminated organic molecules is formed on the gold surface. Herein, we suggested that a monolayer of L-cysteine deposited on a gold surface can act as a buffer layer to immobilize biomolecules on the metal surface. We selected lactic acid as the immobilized biomolecule because it is one of the simplest carboxyl-containing biomolecules. The immobilization of lactic acid on the metal surface was carried out by an electrochemical method in an aqueous environment under the potential range varying from − 0.6 to + 0.8 V. The surface chemical states before and after the electrochemical reaction were characterized using X-ray photoelectron spectroscopy (XPS). The N 1s and C 1s XPS spectra showed that the L-cysteine-modified gold surface can immobilize lactic acid via peptide bonds. This technique might enable the immobilization of large organic molecules and biomolecules. - Highlights: • Monolayer l-cysteine deposited on Au surface as a buffer layer to immobilize biomolecules. • Lactic acid as the immobilized biomolecule as it is simple carboxyl-containing biomolecule. • X-ray photoelectron spectroscopy (XPS) of surface chemical states, before and after. • L-cysteine-modified Au surface can immobilize lactic acid via peptide bonds

  3. Immobilization of biomolecules onto surfaces according to ultraviolet light diffraction patterns

    DEFF Research Database (Denmark)

    Petersen, Steffen B.; Gennaro, Ane Kold Di; Neves Petersen, Teresa

    2010-01-01

    We developed a method for immobilization of biomolecules onto thiol functionalized surfaces according to UV diffraction patterns. UV light-assisted molecular immobilization proceeds through the formation of free, reactive thiol groups that can bind covalently to thiol reactive surfaces. We demons......, with a fine structured interference pattern superimposed. (C) 2010 Optical Society of America...

  4. Zwitterionic sulfobetaine polymer-immobilized surface by simple tyrosinase-mediated grafting for enhanced antifouling property.

    Science.gov (United States)

    Kwon, Ho Joon; Lee, Yunki; Phuong, Le Thi; Seon, Gyeung Mi; Kim, Eunsuk; Park, Jong Chul; Yoon, Hyunjin; Park, Ki Dong

    2017-10-01

    Introducing antifouling property to biomaterial surfaces has been considered an effective method for preventing the failure of implanted devices. In order to achieve this, the immobilization of zwitterions on biomaterial surfaces has been proven to be an excellent way of improving anti-adhesive potency. In this study, poly(sulfobetaine-co-tyramine), a tyramine-conjugated sulfobetaine polymer, was synthesized and simply grafted onto the surface of polyurethane via a tyrosinase-mediated reaction. Surface characterization by water contact angle measurements, X-ray photoelectron spectroscopy and atomic force microscopy demonstrated that the zwitterionic polymer was successfully introduced onto the surface of polyurethane and remained stable for 7days. In vitro studies revealed that poly(sulfobetaine-co-tyramine)-coated surfaces dramatically reduced the adhesion of fibrinogen, platelets, fibroblasts, and S. aureus by over 90% in comparison with bare surfaces. These results proved that polyurethane surfaces grafted with poly(sulfobetaine-co-tyramine) via a tyrosinase-catalyzed reaction could be promising candidates for an implantable medical device with excellent bioinert abilities. Antifouling surface modification is one of the key strategy to prevent the thrombus formation or infection which occurs on the surface of biomaterial after transplantation. Although there are many methods to modify the surface have been reported, necessity of simple modification technique still exists to apply for practical applications. The purpose of this study is to modify the biomaterial's surface by simply immobilizing antifouling zwitterion polymer via enzyme tyrosinase-mediated reaction which could modify versatile substrates in mild aqueous condition within fast time period. After modification, pSBTA grafted surface becomes resistant to various biological factors including proteins, cells, and bacterias. This approach appears to be a promising method to impart antifouling property on

  5. Influence of acetylcholinesterase immobilization on the photoluminescence properties of mesoporous silicon surface

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, Muhammad [Department of Chemistry, Kongju National University, Gongju, Chungnam 314-701 (Korea, Republic of); Rafiq, Muhammad; Seo, Sung-Yum [Department of Biology, Kongju National University, Gongju, Chungnam 314-701 (Korea, Republic of); Lee, Ki Hwan, E-mail: khlee@kongju.ac.kr [Department of Chemistry, Kongju National University, Gongju, Chungnam 314-701 (Korea, Republic of)

    2014-07-01

    Acetylcholinesterase immobilized p-type porous silicon surface was prepared by covalent attachment. The immobilization procedure was based on support surface chemical oxidation, silanization, surface activation with cyanuric chloride and finally covalent attachment of free enzyme on the cyanuric chloride activated porous silicon surface. Different pore diameter of porous silicon samples were prepared by electrochemical etching in HF based electrolyte solution and appropriate sample was selected suitable for enzyme immobilization with maximum trapping ability. The surface modification was studied through field emission scanning electron microscope, EDS, FT-IR analysis, and photoluminescence measurement by utilizing the fluctuation in the photoluminescence of virgin and enzyme immobilized porous silicon surface. Porous silicon showed strong photoluminescence with maximum emission at 643 nm and immobilization of acetylcholinesterase on porous silicon surface cause considerable increment on the photoluminescence of porous silicon material while acetylcholinesterase free counterpart did not exhibit any fluorescence in the range of 635–670 nm. The activities of the free and immobilized enzymes were evaluated by spectrophotometric method by using neostigmine methylsulfate as standard enzyme inhibitor. The immobilized enzyme exhibited considerable response toward neostigmine methylsulfate in a dose dependent manner comparable with that of its free counterpart alongside enhanced stability, easy separation from the reaction media and significant saving of enzyme. It was believed that immobilized enzyme can be exploited in organic and biomolecule synthesis possessing technical and economical prestige over free enzyme and prominence of easy separation from the reaction mixture.

  6. Influence of acetylcholinesterase immobilization on the photoluminescence properties of mesoporous silicon surface

    International Nuclear Information System (INIS)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2014-01-01

    Acetylcholinesterase immobilized p-type porous silicon surface was prepared by covalent attachment. The immobilization procedure was based on support surface chemical oxidation, silanization, surface activation with cyanuric chloride and finally covalent attachment of free enzyme on the cyanuric chloride activated porous silicon surface. Different pore diameter of porous silicon samples were prepared by electrochemical etching in HF based electrolyte solution and appropriate sample was selected suitable for enzyme immobilization with maximum trapping ability. The surface modification was studied through field emission scanning electron microscope, EDS, FT-IR analysis, and photoluminescence measurement by utilizing the fluctuation in the photoluminescence of virgin and enzyme immobilized porous silicon surface. Porous silicon showed strong photoluminescence with maximum emission at 643 nm and immobilization of acetylcholinesterase on porous silicon surface cause considerable increment on the photoluminescence of porous silicon material while acetylcholinesterase free counterpart did not exhibit any fluorescence in the range of 635–670 nm. The activities of the free and immobilized enzymes were evaluated by spectrophotometric method by using neostigmine methylsulfate as standard enzyme inhibitor. The immobilized enzyme exhibited considerable response toward neostigmine methylsulfate in a dose dependent manner comparable with that of its free counterpart alongside enhanced stability, easy separation from the reaction media and significant saving of enzyme. It was believed that immobilized enzyme can be exploited in organic and biomolecule synthesis possessing technical and economical prestige over free enzyme and prominence of easy separation from the reaction mixture.

  7. Fabrication of anticoagulation layer on titanium surface by sequential immobilization of poly (ethylene glycol) and albumin.

    Science.gov (United States)

    Pan, Chang-Jiang; Hou, Yan-Hua; Zhang, Bin-Bin; Zhang, Lin-Cai

    2014-01-01

    This paper presents a simple method to sequentially immobilize poly (ethylene glycol) (PEG) and albumin on titanium surface to enhance the blood compatibility. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis indicated that PEG and albumin were successfully immobilized on the titanium surface. Water contact angle results showed a better hydrophilic surface after the immobilization. The immobilized PEG or albumin can not only obviously prevent platelet adhesion and activation but also prolong activated partial thromboplastin time (APTT), leading to the improved anticoagulation. Moreover, immobilization of albumin on PEG-modified surface can further improve the anticoagulation. The approach in the present study provides an effective and efficient method to improve the anticoagulation of blood-contact biomedical devices such as coronary stents.

  8. Immobilization of biomolecules onto surfaces according to ultraviolet light diffraction patterns

    International Nuclear Information System (INIS)

    Bjoern Petersen, Steffen; Kold di Gennaro, Ane; Neves-Petersen, Maria Teresa; Skovsen, Esben; Parracino, Antonietta

    2010-01-01

    We developed a method for immobilization of biomolecules onto thiol functionalized surfaces according to UV diffraction patterns. UV light-assisted molecular immobilization proceeds through the formation of free, reactive thiol groups that can bind covalently to thiol reactive surfaces. We demonstrate that, by shaping the pattern of the UV light used to induce molecular immobilization, one can control the pattern of immobilized molecules onto the surface. Using a single-aperture spatial mask, combined with the Fourier transforming property of a focusing lens, we show that submicrometer (0.7 μm) resolved patterns of immobilized prostate-specific antigen biomolecules can be created. If a dual-aperture spatial mask is used, the results differ from the expected Fourier transform pattern of the mask. It appears as a superposition of two diffraction patterns produced by the two apertures, with a fine structured interference pattern superimposed.

  9. Active-site titration analysis of surface influence on immobilized Candida antarctica Lipase B activity

    Science.gov (United States)

    Matrix morphology and surface polarity effects were investigated for Candida antarctica lipase B immobilization. Measurements of the amount of lipase immobilized (bicinchoninic acid method) and the catalyst’s tributyrin hydrolysis activity, coupled with a determination of the lipase’s functional fr...

  10. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches

    International Nuclear Information System (INIS)

    Piai, Juliana Francis; Alves da Silva, Marta; Martins, Albino; Torres, Ana Bela; Faria, Susana

    2017-01-01

    Highlights: • Chemical immobilization of chondroitin sulfate at the surface of nanofiber meshes. • CS-immobilized NFMs showed lower roughness and higher hydrophilicity. • CS-immobilized NFMs offer a highly effective substrate for hACs phenotypic stability. - Abstract: Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O_3 exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  11. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches

    Energy Technology Data Exchange (ETDEWEB)

    Piai, Juliana Francis [3B’s Research Group − Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4805-017 Barco, Guimarães (Portugal); ICVS/3B’s − PT Government Associate Laboratory, Braga/Guimarães (Portugal); Grupo de Materiais Poliméricos e Compósitos, GMPC – Departamento de Química- Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná (Brazil); Alves da Silva, Marta; Martins, Albino; Torres, Ana Bela [3B’s Research Group − Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4805-017 Barco, Guimarães (Portugal); ICVS/3B’s − PT Government Associate Laboratory, Braga/Guimarães (Portugal); Faria, Susana [Research Center Officinal Mathematical, Department of Mathematics for Science and Technology, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); and others

    2017-05-01

    Highlights: • Chemical immobilization of chondroitin sulfate at the surface of nanofiber meshes. • CS-immobilized NFMs showed lower roughness and higher hydrophilicity. • CS-immobilized NFMs offer a highly effective substrate for hACs phenotypic stability. - Abstract: Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O{sub 3} exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  12. Plasma Surface Modification for Immobilization of Bone Morphogenic Protein-2 on Polycaprolactone Scaffolds

    Science.gov (United States)

    Kim, Byung Hoon; Myung, Sung Woon; Jung, Sang Chul; Ko, Yeong Mu

    2013-11-01

    The immobilization of recombinant human bone formation protein-2 (rhBMP-2) on polycaprolactone (PCL) scaffolds was performed by plasma polymerization. RhBMP-2, which induces osteoblast differentiation in various cell types, is a growth factor that plays an important role in bone formation and repair. The surface of the PCL scaffold was functionalized with the carboxyl groups of plasma-polymerized acrylic acid (PPAA) thin films. Plasma polymerization was carried out at a discharge power of 60 W at an acrylic acid flow rate of 7 sccm for 5 min. The PPAA thin film exhibited moderate hydrophilic properties and possessed a high density of carboxyl groups. Carboxyl groups and rhBMP-2 on the PCL scaffolds surface were identified by attenuated total reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The alkaline phosphatase activity assay showed that the rhBMP-2 immobilized PCL scaffold increased the level of MG-63 cell differentiation. Plasma surface modification for the preparation of biomaterials, such as biofunctionalized polymer scaffolds, can be used for the binding of bioactive molecules in tissue engineering.

  13. DNA immobilization on polymer-modified Si surface by controlling pH

    International Nuclear Information System (INIS)

    Demirel, Goekcen Birlik; Caykara, Tuncer

    2009-01-01

    A novel approach based on polymer-modified Si surface as DNA sensor platforms is presented. The polymer-modified Si surface was prepared by using 3-(methacryloxypropyl)trimethoxysilane [γ-MPS] and poly(acrylamide) [PAAm]. Firstly, a layer of γ-MPS was formed on the hydroxylated silicon surface as a monolayer and then modified with different molecular weight of PAAm to form polymer-modified surface. The polymer-modified Si surface was used for dsDNA immobilization. All steps about formation of layer structure were characterized by ellipsometry, atomic force microscopy (AFM), attenuated total reflectance Fourier transformed infrared (ATR-FTIR), and contact angle (CA) measurements. We found that in this case the amount of dsDNA immobilized onto the surface was dictated by the electrostatic interaction between the substrate surface and the DNA. Our results thus demonstrated that DNA molecules could be immobilized differently onto the polymer-modified support surface via electrostatic interactions.

  14. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches

    Science.gov (United States)

    Piai, Juliana Francis; da Silva, Marta Alves; Martins, Albino; Torres, Ana Bela; Faria, Susana; Reis, Rui L.; Muniz, Edvani Curti; Neves, Nuno M.

    2017-05-01

    Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O3 exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  15. Immobilization of Fab' fragments onto substrate surfaces: A survey of methods and applications.

    Science.gov (United States)

    Crivianu-Gaita, Victor; Thompson, Michael

    2015-08-15

    Antibody immobilization onto surfaces has widespread applications in many different fields. It is desirable to bind antibodies such that their fragment-antigen-binding (Fab) units are oriented away from the surface in order to maximize analyte binding. The immobilization of only Fab' fragments yields benefits over the more traditional whole antibody immobilization technique. Bound Fab' fragments display higher surface densities, yielding a higher binding capacity for the analyte. The nucleophilic sulfide of the Fab' fragments allows for specific orientations to be achieved. For biosensors, this indicates a higher sensitivity and lower detection limit for a target analyte. The last thirty years have shown tremendous progress in the immobilization of Fab' fragments onto gold, Si-based, polysaccharide-based, plastic-based, magnetic, and inorganic surfaces. This review will show the current scope of Fab' immobilization techniques available and illustrate methods employed to minimize non-specific adsorption of undesirables. Furthermore, a variety of examples will be given to show the versatility of immobilized Fab' fragments in different applications and future directions of the field will be addressed, especially regarding biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Immobilization of microbial cells on cellulose-polymer surfaces by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1983-01-01

    Streptomyces phaeochromogens cells were immobilized on cellulose-polymer surfaces by radiation polymerization using hydrophilic monomers and paper. The enzyme activity of immobilized cell sheets was higher than that of immobilized cell composites obtained by the usual radiation polymerization technique. The enzyme activity of the sheets was affected by monomer concentration, the thickness of paper, and the degree of polymerization of paper. The copolymerization of hydroxyethyl methacrylate and methoxytetraethyleneglycol methacrylate in the sheets led to a further increase of the enzyme activity due to the increase of the hydrophilicity of the polymer matrix. The Michaelis constant of the sheets from low monomer concentration was close to that of intact cells

  17. Immobilization of Ag nanoparticles/FGF-2 on a modified titanium implant surface and improved human gingival fibroblasts behavior.

    Science.gov (United States)

    Ma, Qianli; Mei, Shenglin; Ji, Kun; Zhang, Yumei; Chu, Paul K

    2011-08-01

    The objective of this study was to form a rapid and firm soft tissue sealing around dental implants that resists bacterial invasion. We present a novel approach to modify Ti surface by immobilizing Ag nanoparticles/FGF-2 compound bioactive factors onto a titania nanotubular surface. The titanium samples were anodized to form vertically organized TiO(2) nanotube arrays and Ag nanoparticles were electrodeposited onto the nanotubular surface, on which FGF-2 was immobilized with repeated lyophilization. A uniform distribution of Ag nanoparticles/FGF-2 was observed on the TiO(2) nanotubular surface. The L929 cell line was used for cytotoxicity assessment. Human gingival fibroblasts (HGFs) were cultured on the modified surface for cytocompatibility determination. The Ag/FGF-2 immobilized samples displayed excellent cytocompatibility, negligible cytotoxicity, and enhanced HGF functions such as cell attachment, proliferation, and ECM-related gene expression. The Ag nanoparticles also exhibit some bioactivity. In conclusion, this modified TiO(2) nanotubular surface has a large potential for use in dental implant abutment. Copyright © 2011 Wiley Periodicals, Inc.

  18. Stable functionalization of germanium surface and its application in biomolecules immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Qi [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A, Yuquan Road, Beijing 100049 (China); Xu, Baojian [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Ye, Lin [Sate Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A, Yuquan Road, Beijing 100049 (China); Tang, Teng; Huang, Shanluo; Du, Xiaowei [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A, Yuquan Road, Beijing 100049 (China); Bian, Xiaojun; Zhang, Jishen [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Di, Zengfeng, E-mail: zfdi@mail.sim.ac.cn [Sate Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Jin, Qinghui [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China); Zhao, Jianlong, E-mail: jlzhao@mail.sim.ac.cn [State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, No.865, Changning Road, Shanghai 200050 (China)

    2014-10-15

    Highlights: • An effective method to immobilize biomolecules on the functionalized Ge surface. • The surface of Ge was functionalized with 11-Mercaptoundecanoic acid (11-MUA). • Stable and uniform SAMs was obtained on Ge surface after 11-MUA treatment. • The functionalized Ge was employed as substrate for protein immobilization. • Paving the way of Ge for further applications in bioelectronics field. - Abstract: As a typical semiconductor material, germanium (Ge) has the potential to be utilized in microelectronics and bioelectronics. Herein, we present a simple and effective method to immobilize biomolecules on the surface of functionalized Ge. The surface oxide of Ge was removed with the pretreatment of hydrochloric acid and the Cl-terminated Ge reacted with 11-Mercaptoundecanoic acid (11-MUA). The surface of Ge was coated with 11-MUA self-assembled monolayers (SAMs) due to the bonding reaction between the sulfhydryl group of 11-MUA and Cl-terminated Ge. Furthermore, typical biomolecule, a green fluorescent protein was chosen to be immobilized on the surface of the functionalized Ge. Contact angle analysis, atomic force microscopy and X-ray photoelectron spectroscopy were used to study the characteristics including wettability, stability, roughness and component of the functionalized Ge, respectively. Fluorescence microscopy was utilized to indicate the efficiency of protein immobilization on the surface of the functionalized Ge. With these studies, stable and uniform functionalized monolayer was obtained on the surface of Ge after 11-MUA treatment and the functionalized Ge was effectively applied in protein immobilization. Furthermore, this study may pave the way for further applications such as the integration of bioelectronics and biosensors with the attractive semiconductor material-Ge in future work.

  19. AFM imaging of bacteria in liquid media immobilized on gelatin coated mica surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Doktycz, M.J.; Sullivan, C.J.; Hoyt, P.R.; Pelletier, D.A.; Wu, S.; Allison, D.P

    2003-10-15

    Immobilization of particulates, especially biomolecules and cells, onto surfaces is critical for imaging with the atomic force microscope (AFM). In this paper, gelatin coated mica surfaces are shown to be suitable for immobilizing and imaging both gram positive, Staphylococcus aureus, and gram negative, Escherichia coli, bacteria in both air and liquid environments. Gelatin coated surfaces are shown to be superior to poly-L-lysine coated surfaces that are commonly used for the immobilization of cells. This cell immobilization technique is being developed primarily for live cell imaging of Rhodopseudomonas palustris. The genome of R. palustris has been sequenced and the organism is the target of intensive studies aimed at understanding genome function. Images of R. palustris grown both aerobically and anaerobically in liquid media are presented. Images in liquid media show the bacteria is rod shaped and smooth while images in air show marked irregularity and folding of the surface. Significant differences in the vertical dimension are also apparent with the height of the bacteria in liquid being substantially greater than images taken in air. In air immobilized bacterial flagella are clearly seen while in liquid this structure is not visible. Additionally, significant morphological differences are observed that depend on the method of bacterial growth.

  20. Method for selective immobilization of macromolecules on self assembled monolayer surfaces

    Science.gov (United States)

    Laskin, Julia [Richland, WA; Wang, Peng [Billerica, MA

    2011-11-29

    Disclosed is a method for selective chemical binding and immobilization of macromolecules on solid supports in conjunction with self-assembled monolayer (SAM) surfaces. Immobilization involves selective binding of peptides and other macromolecules to SAM surfaces using reactive landing (RL) of mass-selected, gas phase ions. SAM surfaces provide a simple and convenient platform for tailoring chemical properties of a variety of substrates. The invention finds applications in biochemistry ranging from characterization of molecular recognition events at the amino acid level and identification of biologically active motifs in proteins, to development of novel biosensors and substrates for stimulated protein and cell adhesion.

  1. Photochemical immobilization of anthraquinone conjugated oligonucleotides and PCR amplicons on solid surfaces

    DEFF Research Database (Denmark)

    Koch, T.; Jacobsen, N.; Fensholdt, J.

    2000-01-01

    Ligand immobilization on solid surfaces is an essential step in fields such as diagnostics, bio sensor manufacturing, and new material sciences in general. In this paper a photochemical approach based on anthraquinone as the chromophore is presented. Photochemical procedures offer special...... advantages as they are able to generate highly reactive species in an orientation specific manner. As presented here, anthraquinone (AQ) mediated covalent DNA immobilization appears to be superior to currently known procedures. A synthetic procedure providing AQ-phosphoramidites is presented. These reagents...... facilitate AQ conjugation during routine DNA synthesis, thus enabling the AQ-oligonucleotides to be immobilized in a very convenient and efficient manner. AQ-conjugated PCR primers can be used directly in PCR. When the PCR is performed in solution, the amplicons can be immobilized after the PCR. Moreover...

  2. Alteration of cartilage surface collagen fibers differs locally after immobilization of knee joints in rats

    Science.gov (United States)

    Nagai, Momoko; Aoyama, Tomoki; Ito, Akira; Tajino, Junichi; Iijima, Hirotaka; Yamaguchi, Shoki; Zhang, Xiangkai; Kuroki, Hiroshi

    2015-01-01

    The purpose of this study was to examine the ultrastructural changes of surface cartilage collagen fibers, which differ by region and the length of the experimental period in an immobilization model of rat. Male Wistar rats were randomly divided into histological or macroscopic and ultrastructural assessment groups. The left knees of all the animals were surgically immobilized by external fixation for 1, 2, 4, 8 or 16 weeks (n = 5/time point). Sagittal histological sections of the medial mid-condylar region of the knee were obtained and assessed in four specific regions (contact and peripheral regions of the femur and tibia) and two zones (superficial and deep). To semi-quantify the staining intensity of the collagen fibers in the cartilage, picrosirius red staining was used. The cartilage surface changes of all the assessed regions were investigated by scanning electron microscopy (SEM). From histological and SEM observations, the fibrillation and irregular changes of the cartilage surface were more severe in the peripheral region than in the contact region. Interestingly, at 16 weeks post-immobilization, we observed non-fibrous structures at both the contact and peripheral regions. The collagen fiber staining intensity decreased in the contact region compared with the peripheral region. In conclusion, the alteration of surface collagen fiber ultrastructure and collagen staining intensity differed by the specific cartilage regions after immobilization. These results demonstrate that the progressive degeneration of cartilage is region specific, and depends on the length of the immobilization period. PMID:25939458

  3. Immobilization of the Enzyme Glucose Oxidase on Both Bulk and Porous SiO2 Surfaces

    Directory of Open Access Journals (Sweden)

    Fulvia Sinatra

    2008-09-01

    Full Text Available Silicon dioxide surfaces, both bulk and porous, were used to anchor the enzyme glucose oxidase. The immobilization protocol was optimized and the samples characterized using X-ray Photoelectron Spectroscopy, Energy Dispersive X-rays coupled to scanning electron microscopy and enzymatic activity measurements. We show that a uniform layer was obtained by activating the oxide before immobilization. X-ray Photoelectron Spectroscopy measurements carried out on bulk oxide showed that the silicon substrate signal was fully screened after the enzyme deposition showing the absence of uncovered surface regions. The enzyme presence was detected monitoring both the C 1s and N 1s signals. Finally, enzymatic activity measurements confirmed that the glucose oxidase activity was preserved after immobilization and maintained after three months of shelf life if the sample was properly stored. The importance of using porous silicon oxide to maximize the surface area was also evidenced.

  4. Electric fields control the orientation of peptides irreversibly immobilized on radical-functionalized surfaces.

    Science.gov (United States)

    Martin, Lewis J; Akhavan, Behnam; Bilek, Marcela M M

    2018-01-24

    Surface functionalization of an implantable device with bioactive molecules can overcome adverse biological responses by promoting specific local tissue integration. Bioactive peptides have advantages over larger protein molecules due to their robustness and sterilizability. Their relatively small size presents opportunities to control the peptide orientation on approach to a surface to achieve favourable presentation of bioactive motifs. Here we demonstrate control of the orientation of surface-bound peptides by tuning electric fields at the surface during immobilization. Guided by computational simulations, a peptide with a linear conformation in solution is designed. Electric fields are used to control the peptide approach towards a radical-functionalized surface. Spontaneous, irreversible immobilization is achieved when the peptide makes contact with the surface. Our findings show that control of both peptide orientation and surface concentration is achieved simply by varying the solution pH or by applying an electric field as delivered by a small battery.

  5. Exposure Scenarios and Unit Dose Factors for the Hanford Immobilized Low Activity Tank Waste Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    RITTMANN, P.D.

    1999-12-29

    Exposure scenarios are defined to identify potential pathways and combinations of pathways that could lead to radiation exposure from immobilized tank waste. Appropriate data and models are selected to permit calculation of dose factors for each exposure

  6. Surface engineering of Ti-O films by photochemical immobilization of gelatin

    International Nuclear Information System (INIS)

    Weng, Y.J.; Ren, J.R.; Huang, N.; Wang, J.; Chen, J.Y.; Leng, Y.X.; Liu, H.Q.

    2008-01-01

    Crystalline Ti-O films were prepared by unbalanced magnetron sputtering and the structure was confirmed by XRD. An organic layer of 3-aminopropylphosphonic acid (APP) was first introduced on the Ti-O films by self-assembling. The stability of the APP on Ti-O films was confirmed by XPS and FTIR analysis. Simultaneously, azido group was introduced in gelatin molecule to act as photoreactive point. The derivated gelatin was spin-coated onto the self-assembled layer and immobilized by UV irradiating. Chemical patterned surface was obtained by using a photomask when irradiating and confirmed by sirius red staining and surface profile analysis. Measured by surface profilometer, the thickness of the immobilized gelatin was about 5-20 nm. The adhering of human endothelial EVC304 cells on APP modified surface was enhanced in the cell culture test. Moreover, the adherence and growth of cells were prior on gelatin-immobilized region visually seen on the patterned surface. This result indicated gelatin-immobilized Ti-O surface can serve as a biocompatible biomaterial for endothelialization

  7. Co-immobilization of semaphorin3A and nerve growth factor to guide and pattern axons.

    Science.gov (United States)

    McCormick, Aleesha M; Jarmusik, Natalie A; Leipzig, Nic D

    2015-12-01

    Immobilization of axon guidance cues offers a powerful tissue regenerative strategy to control the presentation and spatial location of these biomolecules. We use our previously developed immobilization strategy to specifically tether recombinant biotinylated nerve growth factor (bNGF) and biotinylated semaphorin3A (bSema3A) to chitosan films as an outgrowth and guidance platform. DRG neurite length and number for a range of single cues of immobilized bNGF or bSema3A were examined to determine a concentration response. Next single and dual cues of bNGF and bSema3A were immobilized and DRG guidance was assessed in response to a step concentration change from zero. Overall, immobilized groups caused axon extension, retraction and turning depending on the ratio of bNGF and bSema3A immobilized in the encountered region. This response indicated the exquisite sensitivity of DRG axons to both attractive and repulsive tethered cues. bSema3A concentrations of 0.10 and 0.49 ng/mm(2), when co-immobilized with bNGF (at 0.86 and 0.43 ng/mm(2) respectively), caused axons to turn away from the co-immobilized region. Immunocytochemical analysis showed that at these bSema3A concentrations, axons inside the co-immobilized region display microtubule degradation and breakdown of actin filaments. At the lowest bSema3A concentration (0.01 ng/mm(2)) co-immobilized with a higher bNGF concentration (2.16 ng/mm(2)), neurite lengths are shorter in the immobilized area, but bNGF dominates the guidance mechanism as neurites are directed toward the immobilized region. Future applications can pattern these cues in various geometries and gradients in order to better modulate axon guidance in terms of polarity, extension and branching. Nervous system formation and regeneration requires key molecules for guiding the growth cone and nervous system patterning. In vivo these molecules work in conjunction with one another to modulate axon guidance, and often they are tethered to limit spatial

  8. Novel immobilizations of an adhesion peptide on the TiO2 surface: An XPS investigation

    International Nuclear Information System (INIS)

    Iucci, G.; Dettin, M.; Battocchio, C.; Gambaretto, R.; Bello, C. Di; Polzonetti, G.

    2007-01-01

    The covalent attachment of an adhesive peptide, reproducing the 351-359 sequence of human vitronectin, to oxidized titanium surfaces was investigated by XPS spectroscopy. The peptide enhances osteoblast adhesion to titanium, the most used biomaterial for implants and prostheses. Core level spectra of the TiO 2 surface and of the biomimetic surface were investigated. Novel selective covalent immobilization of (351-359) HVP was carried out by treatment of the TiO 2 surface with (3-aminopropyl) triethoxysilane, glutaric anhydride and a side chain protected peptide sequence presenting only a free terminal amino group, followed by side chain deprotection. An alternative strategy for covalent attachment consists in photoactivation of physisorbed (351-359) HVP directly on the TiO 2 surface; samples were incubated with HVP solution and subsequently irradiated with UV light. A comparison with the results previously obtained for non-selective HVP immobilization will be discussed

  9. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    Van Der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; Van Der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  10. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water.

    NARCIS (Netherlands)

    Grift, van der B.; Rozemeijer, J.C.; Griffioen, J.; Velde, van der Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and 5 P immobilization along the flow-path

  11. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  12. Covalent immobilization of stem cell factor and stromal derived factor 1α for in vitro culture of hematopoietic progenitor cells.

    Science.gov (United States)

    Cuchiara, Maude L; Horter, Kelsey L; Banda, Omar A; West, Jennifer L

    2013-12-01

    Hematopoietic stem cells (HSCs) are currently utilized in the treatment of blood diseases, but widespread application of HSC therapeutics has been hindered by the limited availability of HSCs. With a better understanding of the HSC microenvironment and the ability to precisely recapitulate its components, we may be able to gain control of HSC behavior. In this work we developed a novel, biomimetic PEG hydrogel material as a substrate for this purpose and tested its potential with an anchorage-independent hematopoietic cell line, 32D clone 3 cells. We immobilized a fibronectin-derived adhesive peptide sequence, RGDS; a cytokine critical in HSC self-renewal, stem cell factor (SCF); and a chemokine important in HSC homing and lodging, stromal derived factor 1α (SDF1α), onto the surfaces of poly(ethylene glycol) (PEG) hydrogels. To evaluate the system's capabilities, we observed the effects of the biomolecules on 32D cell adhesion and morphology. We demonstrated that the incorporation of RGDS onto the surfaces promotes 32D cell adhesion in a dose-dependent fashion. We also observed an additive response in adhesion on surfaces with RGDS in combination with either SCF or SDF1α. In addition, the average cell area increased and circularity decreased on gel surfaces containing immobilized SCF or SDF1α, indicating enhanced cell spreading. By recapitulating aspects of the HSC microenvironment using a PEG hydrogel scaffold, we have shown the ability to control the adhesion and spreading of the 32D cells and demonstrated the potential of the system for the culture of primary hematopoietic cell populations. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. Analysis of direct immobilized recombinant protein G on a gold surface

    International Nuclear Information System (INIS)

    Kim, Hyunhee; Kang, Da-Yeon; Goh, Hyun-Jeong; Oh, Byung-Keun; Singh, Ravindra P.; Oh, Soo-Min; Choi, Jeong-Woo

    2008-01-01

    Abstact: For the immobilization of IgG, various techniques such as chemical linker, thiolated protein G methods, and fragmentation of antibodies have been reported [Y.M. Bae, B.K. Oh, W. Lee, W.H. Lee, J.W. Choi, Biosensors Bioelectron. 21 (2005) 103; W. Lee, B.K. Oh, W.H. Lee, J.W. Choi, Colloids Surf. B-Biointerfaces, 40 (2005) 143; A.A. Karyakin, G.V. Presnova, M.Y. Rubtsova, A.M. Egorov, Anal. Chem. 72 (2000) 3805]. Here, we modified the immunoglobulin Fc-binding B-domain of protein G to contain two cysteine residues at its C-terminus by a genetic engineering technique. The resulting recombinant protein, RPGcys, retained IgG-binding activity in the same manner as native protein G. RPGcys was immobilized on a gold surface by strong affinity between thiol of cysteine and gold. The orientations of both IgG layers immobilized on the base recombinant protein Gs were analyzed by fluorescence microscope, atomic force microscope (AFM), and surface plasmon resonance (SPR). Our data revealed that IgG-binding activity of RPGcys on gold surface significantly increased in comparison to wild type of protein G (RPGwild), which was physically adsorbed due to absence of cysteine residue. Immobilization of highly oriented antibodies based on cysteine-modified protein G could be useful for the fabrication of immunosensor systems

  14. Three-dimensional immobilization of beta-galactosidase on a silicon surface.

    Science.gov (United States)

    Betancor, Lorena; Luckarift, Heather R; Seo, Jae H; Brand, Oliver; Spain, Jim C

    2008-02-01

    Many alternative strategies to immobilize and stabilize enzymes have been investigated in recent years for applications in biosensors. The entrapment of enzymes within silica-based nanospheres formed through silicification reactions provides high loading capacities for enzyme immobilization, resulting in high volumetric activity and enhanced mechanical stability. Here we report a strategy for chemically associating silica nanospheres containing entrapped enzyme to a silicon support. beta-galactosidase from E. coli was used as a model enzyme due to its versatility as a biosensor for lactose. The immobilization strategy resulted in a three-dimensional network of silica attached directly at the silicon surface, providing a significant increase in surface area and a corresponding 3.5-fold increase in enzyme loading compared to enzyme attached directly at the surface. The maximum activity recovered for a silicon square sample of 0.5 x 0.5 cm was 0.045 IU using the direct attachment of the enzyme through glutaraldehyde and 0.16 IU when using silica nanospheres. The immobilized beta-galactosidase prepared by silica deposition was stable and retained more than 80% of its initial activity after 10 days at 24 degrees C. The ability to generate three-dimensional structures with enhanced loading capacity for biosensing molecules offers the potential to substantially amplify biosensor sensitivity. (c) 2007 Wiley Periodicals, Inc.

  15. Immobilization of glucoamylase on ceramic membrane surfaces modified with a new method of treatment utilizing SPCP-CVD.

    Science.gov (United States)

    Ida; Matsuyama; Yamamoto

    2000-07-01

    Glucoamylase, as a model enzyme, was immobilized on a ceramic membrane modified by surface corona discharge induced plasma chemical process-chemical vapor deposition (SPCP-CVD). Characterizations of the immobilized enzyme were then discussed. Three kinds of ceramic membranes with different amounts of amino groups on the surface were prepared utilizing the SPCP-CVD method. Each with 1-time, 3-times and 5-times surface modification treatments and used for supports in glucoamylase immobilization. The amount of immobilized glucoamylase increased with the increase in the number of surface modification treatments and saturated to a certain maximum value estimated by a two-dimensional random packing. The operational stability of the immobilized glucoamylase also increased with the increase in the number of the surface treatment. It was almost the same as the conventional method, while the activity of immobilized enzyme was higher. The results indicated the possibility of designing the performance of the immobilized enzyme by controlling the amount of amino groups. The above results showed that the completely new surface modification method using SPCP was effective in modifying ceramic membranes for enzyme immobilization.

  16. Antimicrobial membrane surfaces via efficient polyethyleneimine immobilization and cationization

    Science.gov (United States)

    Qiu, Wen-Ze; Zhao, Zi-Shu; Du, Yong; Hu, Meng-Xin; Xu, Zhi-Kang

    2017-12-01

    Biofouling control is a major task in membrane separation processes for water treatment and biomedical applications. In this work, N-alkylated polyethylenimine (PEI) is facilely and efficiently introduced onto the membrane surfaces via the co-deposition of catechol (CCh) and PEI, followed by further grafting of PEIs (600 Da, 70 kDa and 750 kDa) and cationization with methyl iodide (CH3I). The physical and chemical properties of the constructed membrane surfaces are characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential and water contact angle measurements. Antibacterial assay reveals that the optimized membrane surfaces possess around 95% antibacterial efficiency against Gram-positive Staphylococcus aureus (S. aureus) with weak adhesion of bacteria cells after 24 h of bacterial contact. Additionally, the membrane surfaces also exhibit much enhanced antifouling property during the filtration of opposite charged bovine serum albumin (BSA). These results demonstrate a useful strategy for the surface modification of separation membranes by a kind of antimicrobial and antifouling coating.

  17. Use of activated carbon as a support medium for H2S biofiltration and effect of bacterial immobilization on available pore surface.

    Science.gov (United States)

    Ng, Y L; Yan, R; Chen, X G; Geng, A L; Gould, W D; Liang, D T; Koe, L C C

    2004-12-01

    The use of support media for the immobilization of microorganisms is widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In this study, activated carbon is used as a support medium for the immobilization of microorganisms enriched from municipal sewage activated sludge to remove gas-phase hydrogen sulfide (H2S), a major odorous component of waste gas from sewage treatment plants. A series of designed experiments is used to examine the effect on bacteria-immobilized activated carbon (termed "biocarbon") due to physical adsorption, chemical reaction, and microbial degradation in the overall removal of H2S. H2S breakthrough tests are conducted with various samples, including microbe-immobilized carbon and Teflon discs, salts-medium-washed carbon, and ultra-pure water-washed carbon. The results show a higher removal capacity for the microbe-immobilized activated carbon compared with the activated carbon control in a batch biofilter column. The increase in removal capacity is attributed to the role played by the immobilized microorganisms in metabolizing adsorbed sulfur and sulfur compounds on the biocarbon, hence releasing the adsorption sites for further H2S uptake. The advantage for activated carbon serving as the support medium is to adsorb a high initial concentration of substrate and progressively release this for microbial degradation, hence acting as a buffer for the microorganisms. Results obtained from surface area and pore size distribution analyses of the biocarbon show a correlation between the available surface area and pore volume with the extent of microbial immobilization and H2S uptake. The depletion of surface area and pore volume is seen as one of the factors which cause the onset of column breakthrough. Microbial growth retardation is due to the accumulation of metabolic products (i.e., sulfuric acid); and a lack of water and nutrient salts in the batch biofilter are other

  18. Factors affecting the immobilization of fungal biomass on CNT as a biosorbent for textile dyes removal

    Science.gov (United States)

    Adebayo Bello, Ibrahim; Kabbashi, Nassereldeen A.; Zahangir Alam, Md; Alkhatib, Ma'an F.; Nabilah Murad, Fatin

    2017-07-01

    Effluents from dye and textile industries are highly contaminated and toxic to the environment. High concentration of non-biodegradable compounds contributes to increased biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the wastewater bodies. Dyes found in wastewater from textile industries are carcinogenic, mutagenic or teratogenic. Biological processes involving certain bacteria, fungi and activated carbon have been employed in treating wastewater. These methods are either inefficient or ineffective. These complexities necessitates search for new approaches that will offset all the shortcomings of the present solutions to the challenges faced with textile wastewater management. This study produced a new biosorbent by the immobilization of fungal biomass on carbon nanotubes. The new biosorbent is called “carbon nanotubes immobilized biomass (CNTIB)” which was produced by immobilization technique. A potential fungal strain, Aspergillus niger was selected on the basis of biomass production. It was found out in this studies that fungal biomass were better produced in acidic medium. Aspergillus niger was immobilized on carbon nanotubes. One-factor-at-a time (OFAT) was employed to determine the effect of different factors on the immobilization of fungal biomass on carbon nanotubes and optimum levels at which the three selected parameters (pH, culture time and agitation rate) would perform. Findings from OFAT showed that the optimum conditions for immobilization are a pH of 5, agitation rate of 150rpm and a culture time of 5 days.

  19. Kinetic analysis of inhibition of glucoamylase and active site mutants via chemoselective oxime immobilization of acarbose on SPR chip surfaces

    DEFF Research Database (Denmark)

    Sauer, Jørgen; Abou Hachem, Maher; Svensson, Birte

    2013-01-01

    shown that at pH 7.0 the association and dissociation rate constants for the acarbose-glucoamylase interaction are 104M−1s−1 and 103s−1, respectively, and that the conformational change to a tight enzyme–inhibitor complex affects the dissociation rate constant by a factor of 102s−1. Additionally......, the acarbose-presenting SPR surfaces could be used as a glucoamylase sensor that allowed rapid, label-free affinity screening of small carbohydrate-based inhibitors in solution, which is otherwise difficult with immobilized enzymes or other proteins....

  20. Concentration- and time-dependent response of human gingival fibroblasts to fibroblast growth factor 2 immobilized on titanium dental implants

    Directory of Open Access Journals (Sweden)

    Ma Q

    2012-04-01

    Full Text Available Qianli Ma1*, Wei Wang1*, Paul K Chu2, Shenglin Mei1,2, Kun Ji3, Lei Jin4, Yumei Zhang11Department of Prosthetic Dentistry, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China; 2Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong, People's Republic of China; 3Department of Pediatric Dentistry, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China; 4Stomatology Department, Jinling Hospital, School of Medicine, Southern Medical University, Nanjing, People's Republic of China*These authors contributed equally to this workBackground: Titanium (Ti implants are widely used clinically, but peri-implantitis remains one of the most common and serious complications. Healthy integration between gingival tissue and the implant surface is critical to long-term success in dental implant therapy. The objective of this study was to investigate how different concentrations of immobilized fibroblast growth factor 2 (FGF2 on the titania nanotubular surface influence the response of human gingival fibroblasts (HGFs.Methods: Pure Ti metal was anodized at 20 V to form a vertically organized titanium dioxide nanotube array on which three concentrations of FGF2 (250 ng/mL, 500 ng/mL, or 1000 ng/mL were immobilized by repeated lyophilization. Surface topography was observed and FGF2 elution was detected using enzyme-linked immunosorbent assay. The bioactivity changes of dissolvable immobilized FGF2 were measured by methyl-thiazolyl-tetrazolium assay. Behavior of HGFs was evaluated using adhesion and methyl-thiazolyl-tetrazolium bromide assays.Results: The FGF2 remained for several days on the modified surface on which HGFs were cultured. Over 90% of the dissolvable immobilized FGF2 had been eluted by Day 9, whereas the FGF2 activity was found to diminish gradually from Day 1 to Day 9. The titania nanotubular surface with an optimal preparing

  1. Surface modification of chitosan/PEO nanofibers by air dielectric barrier discharge plasma for acetylcholinesterase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Dorraki, Naghme, E-mail: n.dorraki@web.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Safa, Nasrin Navab [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Jahanfar, Mehdi [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of)

    2015-09-15

    Highlights: • We used an economical and effective method for surface modification. • Chitosan/PEO nanofibrous membranes were modified by air-DBD plasma. • The most NH{sub 3}{sup +} group was generated on the 6 min plasma modified membrane. • We immobilized acetylcholinesterase on the plasma modified and unmodified membranes. • More enzyme activity was detected on the modified membrane by plasma. - Abstract: There are different methods to modify polymer surfaces for biological applications. In this work we have introduced air-dielectric barrier discharge (DBD) plasma at atmospheric pressure as an economical and safe method for modifying the surface of electrospun chitosan/PEO (90/10) nanofibers for acetylcholinesterase (AChE) immobilization. According to the contact angle measurement results, the nanofibers become highly hydrophilic when they are exposed to the DBD plasma for 6 min in compared to unmodified membrane. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results reveal hydroxyl, C=O and NH{sub 3}{sup +} polar groups increment after 6 min plasma treatment. Contact angle measurements and ATR-FTIR results are confirmed by X-ray photoelectron spectroscopy (XPS). AChE at pH 7.4 carries a negative charge and after immobilization on the surface of plasma-treated nanofibrous membrane attracts the NH{sub 3}{sup +} group and more enzyme activity is detected on the plasma-modified nanofibers for 6 min in compared to unmodified nanofibers. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used for the surface topography and morphology characterization. The results have proved that air-DBD plasma is a suitable method for chitosan/PEO nanofibrous membrane modification as a biodegradable and functionalized substrate for enzyme immobilization.

  2. Comparison of Zirconium Phosphonate-Modified Surfaces for Immobilizing Phosphopeptides and Phosphate-Tagged Proteins.

    Science.gov (United States)

    Forato, Florian; Liu, Hao; Benoit, Roland; Fayon, Franck; Charlier, Cathy; Fateh, Amina; Defontaine, Alain; Tellier, Charles; Talham, Daniel R; Queffélec, Clémence; Bujoli, Bruno

    2016-06-07

    Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr(4+), afforded better immobilization of the peptides and proteins and efficient capture of their targets.

  3. Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

    International Nuclear Information System (INIS)

    Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Cardoso, Michael; Rosenfeld, Anatoly; Foo, Kerwyn; Barlin, Sheree

    2011-01-01

    Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

  4. Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

    Science.gov (United States)

    Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Foo, Kerwyn; Cardoso, Michael; Barlin, Sheree; Rosenfeld, Anatoly

    2011-02-01

    Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

  5. Analysis of the surface density and reactivity of perfluorophenylazide and the impact on ligand immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Zorn, Gilad, E-mail: zorn@ge.com; Castner, David G. [National ESCA and Surface Analysis Center for Biomedical Problems, Departments of Bioengineering and Chemical Engineering, University of Washington, Box 351653, Seattle, Washington 98195-1653 (United States); Tyagi, Anuradha; Wang, Xin; Wang, Hui; Yan, Mingdi, E-mail: Mingdi-Yan@uml.edu [Department of Chemistry, Portland State University, Portland, Oregon 97207-0751 (United States)

    2015-03-15

    Perfluorophenylazide (PFPA) chemistry is a novel method for tailoring the surface properties of solid surfaces and nanoparticles. It is general and versatile, and has proven to be an efficient way to immobilize graphene, proteins, carbohydrates, and synthetic polymers. The main thrust of this work is to provide a detailed investigation on the chemical composition and surface density of the PFPA tailored surface. Specifically, gold surfaces were treated with PFPA-derivatized (11-mercaptoundecyl)tetra(ethylene glycol) (PFPA-MUTEG) mixed with 2-[2-(2-mercaptoethoxy)ethoxy]ethanol (MDEG) at varying solution mole ratios. Complementary analytical techniques were employed to characterize the resulting films including Fourier transform infrared spectroscopy to detect fingerprints of the PFPA group, x-ray photoelectron spectroscopy and ellipsometry to study the homogeneity and uniformity of the films, and near edge x-ray absorption fine structures to study the electronic and chemical structure of the PFPA groups. Results from these studies show that the films prepared from 90:10 and 80:20 PFPA-MUTEG/MDEG mixed solutions exhibited the highest surface density of PFPA and the most homogeneous coverage on the surface. A functional assay using surface plasmon resonance with carbohydrates covalently immobilized onto the PFPA-modified surfaces showed the highest binding affinity for lectin on the PFPA-MUTEG/MDEG film prepared from a 90:10 solution.

  6. Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application.

    Science.gov (United States)

    Gonçalves, Juliana P L; Shaikh, Afnan Q; Reitzig, Manuela; Kovalenko, Daria A; Michael, Jan; Beutner, René; Cuniberti, Gianaurelio; Scharnweber, Dieter; Opitz, Jörg

    2014-01-01

    Due to their outstanding properties nanodiamonds are a promising nanoscale material in various applications such as microelectronics, polishing, optical monitoring, medicine and biotechnology. Beyond the typical diamond characteristics like extreme hardness or high thermal conductivity, they have additional benefits as intrinsic fluorescence due to lattice defects without photobleaching, obtained during the high pressure high temperature process. Further the carbon surface and its various functional groups in consequence of the synthesis, facilitate additional chemical and biological modification. In this work we present our recent results on chemical modification of the nanodiamond surface with phosphate groups and their electrochemically assisted immobilization on titanium-based materials to increase adhesion at biomaterial surfaces. The starting material is detonation nanodiamond, which exhibits a heterogeneous surface due to the functional groups resulting from the nitrogen-rich explosives and the subsequent purification steps after detonation synthesis. Nanodiamond surfaces are chemically homogenized before proceeding with further functionalization. Suspensions of resulting surface-modified nanodiamonds are applied to the titanium alloy surfaces and the nanodiamonds subsequently fixed by electrochemical immobilization. Titanium and its alloys have been widely used in bone and dental implants for being a metal that is biocompatible with body tissues and able to bind with adjacent bone during healing. In order to improve titanium material properties towards biomedical applications the authors aim to increase adhesion to bone material by incorporating nanodiamonds into the implant surface, namely the anodically grown titanium dioxide layer. Differently functionalized nanodiamonds are characterized by infrared spectroscopy and the modified titanium alloys surfaces by scanning and transmission electron microscopy. The process described shows an adsorption and

  7. Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application

    Directory of Open Access Journals (Sweden)

    Juliana P. L. Gonçalves

    2014-11-01

    Full Text Available Due to their outstanding properties nanodiamonds are a promising nanoscale material in various applications such as microelectronics, polishing, optical monitoring, medicine and biotechnology. Beyond the typical diamond characteristics like extreme hardness or high thermal conductivity, they have additional benefits as intrinsic fluorescence due to lattice defects without photobleaching, obtained during the high pressure high temperature process. Further the carbon surface and its various functional groups in consequence of the synthesis, facilitate additional chemical and biological modification. In this work we present our recent results on chemical modification of the nanodiamond surface with phosphate groups and their electrochemically assisted immobilization on titanium-based materials to increase adhesion at biomaterial surfaces. The starting material is detonation nanodiamond, which exhibits a heterogeneous surface due to the functional groups resulting from the nitrogen-rich explosives and the subsequent purification steps after detonation synthesis. Nanodiamond surfaces are chemically homogenized before proceeding with further functionalization. Suspensions of resulting surface-modified nanodiamonds are applied to the titanium alloy surfaces and the nanodiamonds subsequently fixed by electrochemical immobilization. Titanium and its alloys have been widely used in bone and dental implants for being a metal that is biocompatible with body tissues and able to bind with adjacent bone during healing. In order to improve titanium material properties towards biomedical applications the authors aim to increase adhesion to bone material by incorporating nanodiamonds into the implant surface, namely the anodically grown titanium dioxide layer. Differently functionalized nanodiamonds are characterized by infrared spectroscopy and the modified titanium alloys surfaces by scanning and transmission electron microscopy. The process described shows an

  8. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    International Nuclear Information System (INIS)

    To, Thien Dien; Nguyen, Anh Tuan; Phan, Khoa Nhat Thanh; Truong, An Thu Thi; Doan, Tin Chanh Duc; Dang, Chien Mau

    2015-01-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES. (paper)

  9. Glucose oxidase immobilization on different modified surfaces of platinum nanowire for application in glucose detection

    International Nuclear Information System (INIS)

    Le, Thi Thanh Tuyen; Tran, Phu Duy; Pham, Xuan Tung; Tong, Duy Hien; Dang, Mau Chien

    2010-01-01

    In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, including a compound of gelatin gel with SiO 2 , polyvinyl alcohol (PVA) with Prussian blue (PB) mediator and cysteamine self-assembled monolayers (SAM). Then, glucose oxidase (GOD) enzyme was immobilized on the modified surfaces of Pt nanowire electrodes by using techniques of electrochemical adsorption and chemical binding. The GOD immobilized Pt nanowires were used for application in glucose detection by performing a cyclic voltammetry measurement. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60 μM was obtained when the Pt nanowires were modified by PVA with PB mediator. Moreover, the sensors showed very high current response when the Pt nanowires were modified with the cysteamine SAM. The stability and catalyst activity of GOD are also reported here. For instance, the catalyst activity of GOD retained about 60% of its initial value after it was stored at 4 °C in a 100 mM PBS buffer solution with a pH of 7.2 for a period of 30 days

  10. Glucose oxidase immobilization on different modified surfaces of platinum nanowire for application in glucose detection

    Science.gov (United States)

    Thanh Tuyen Le, Thi; Duy Tran, Phu; Pham, Xuan Tung; Hien Tong, Duy; Chien Dang, Mau

    2010-09-01

    In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, including a compound of gelatin gel with SiO2, polyvinyl alcohol (PVA) with Prussian blue (PB) mediator and cysteamine self-assembled monolayers (SAM). Then, glucose oxidase (GOD) enzyme was immobilized on the modified surfaces of Pt nanowire electrodes by using techniques of electrochemical adsorption and chemical binding. The GOD immobilized Pt nanowires were used for application in glucose detection by performing a cyclic voltammetry measurement. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60 μM was obtained when the Pt nanowires were modified by PVA with PB mediator. Moreover, the sensors showed very high current response when the Pt nanowires were modified with the cysteamine SAM. The stability and catalyst activity of GOD are also reported here. For instance, the catalyst activity of GOD retained about 60% of its initial value after it was stored at 4 °C in a 100 mM PBS buffer solution with a pH of 7.2 for a period of 30 days.

  11. Enzyme Immobilization on Inorganic Surfaces for Membrane Reactor Applications: Mass Transfer Challenges, Enzyme Leakage and Reuse of Materials

    DEFF Research Database (Denmark)

    Sigurdardóttir, Sigyn Björk; Lehmann, Jonas; Ovtar, Simona

    2018-01-01

    Enzyme immobilization is an established method for the enhancement of enzyme stability and reusability, two factors that are of great importance for industrial biocatalytic applications. Immobilization can be achieved by different methods and on a variety of carrier materials, both organic and in...

  12. Surface functionalization of superparamagnetic nanoparticles encapsulated by chitosan for protein immobilization

    International Nuclear Information System (INIS)

    Sousa, Jose Silva de

    2010-01-01

    Nanoscience and nanotechnology have opened up numerous developments of devices and systems on the nanometer scale, with new molecular organization, properties and functions. In this context, the polymeric magnetic nanoparticles are composites formed by magnetic materials with a particle size between 1 and 100 nm combined with functional polymers. They are well-known and have been widely studied because of its applications in various technology areas. Applications on the biological and medical areas include separation and immobilization of enzymes and proteins, improved techniques of magnetic resonance imaging and diagnostic systems for controlled drug delivery. In this work, proteins were immobilized on the surface of a biopolymer combined with superparamagnetic particles of magnetite. The biopolymer chitosan was used, cross-linked and functionalized with glutaraldehyde, applicable to the biological assays. Three types of magnetic composites were obtained, which were called QM1Glu, QM2NaGlu and QM3Glu. They were characterized by X-ray diffraction, scanning electron microscopy, vibrating sample magnetometry, differential scanning calorimetry, thermogravimetry and infrared spectroscopy. They were evaluated concerning the immobilization of the proteins bovine serum albumin (BSA), collagen and trypsin. The study showed that the immobilization of proteins on the biopolymer occurred in 30 min of incubation. The magnetic composite of non functionalized chitosan (QM3) was also evaluated. For trypsin, it was found that the immobilization potential of QM3 was higher than that observed for QM3Glu. After 30 days, the trypsin of the QM3-Trip and QM3Glu-Trip was still with activity. The activity and the enzyme kinetics of the QM3Glu-Trip with the substrate BApNA were demonstrated. (author)

  13. Protein immobilization on epoxy-activated thin polymer films: effect of surface wettability and enzyme loading.

    Science.gov (United States)

    Chen, Bo; Pernodet, Nadine; Rafailovich, Miriam H; Bakhtina, Asya; Gross, Richard A

    2008-12-02

    A series of epoxy-activated polymer films composed of poly(glycidyl methacrylate/butyl methacrylate/hydroxyethyl methacrylate) were prepared. Variation in comonomer composition allowed exploration of relationships between surface wettability and Candida antartica lipase B (CALB) binding to surfaces. By changing solvents and polymer concentrations, suitable conditions were developed for preparation by spin-coating of uniform thin films. Film roughness determined by AFM after incubation in PBS buffer for 2 days was less than 1 nm. The occurrence of single CALB molecules and CALB aggregates at surfaces was determined by AFM imaging and measurements of volume. Absolute numbers of protein monomers and multimers at surfaces were used to determine values of CALB specific activity. Increased film wettability, as the water contact angle of films increased from 420 to 550, resulted in a decreased total number of immobilized CALB molecules. With further increases in the water contact angle of films from 55 degrees to 63 degrees, there was an increased tendency of CALB molecules to form aggregates on surfaces. On all flat surfaces, two height populations, differing by more than 30%, were observed from height distribution curves. They are attributed to changes in protein conformation and/or orientation caused by protein-surface and protein-protein interactions. The fraction of molecules in these populations changed as a function of film water contact angle. The enzyme activity of immobilized films was determined by measuring CALB-catalyzed hydrolysis of p-nitrophenyl butyrate. Total enzyme specific activity decreased by decreasing film hydrophobicity.

  14. Enhancing anticoagulation and endothelial cell proliferation of titanium surface by sequential immobilization of poly(ethylene glycol) and collagen

    International Nuclear Information System (INIS)

    Pan, Chang-Jiang; Hou, Yan-Hua; Ding, Hong-Yan; Dong, Yun-Xiao

    2013-01-01

    In the present study, poly(ethylene glycol) (PEG) and collagen I were sequentially immobilized on the titanium surface to simultaneously improve the anticoagulation and endothelial cell proliferation. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy analysis confirmed that PEG and collagen I were successfully immobilized on the titanium surface. Water contact angle results suggested the excellent hydrophilic surface after the immobilization. The anticoagulation experiments demonstrated that the immobilized PEG and collagen I on the titanium surface could not only obviously prevent platelet adhesion and aggregation but also prolong activated partial thromboplastin time (APTT), leading to the improved blood compatibility. Furthermore, immobilization of collagen to the end of PEG chain did not abate the anticoagulation. As compared to those on the pristine and PEG-modified titanium surfaces, endothelial cells exhibited improved proliferative profiles on the surface modified by the sequential immobilization of PEG and collagen in terms of CCK-8 assay, implying that the modified titanium may promote endothelialization without abating the blood compatibility. Our method may be used to modify the surface of blood-contacting biomaterials such as titanium to promote endothelialization and improve the anticoagulation, it may be helpful for development of the biomedical devices such as coronary stents, where endothelializaton and excellent anticoagulation are required.

  15. Nano-anisotropic surface coating based on drug immobilized pendant polymer to suppress macrophage adhesion response.

    Science.gov (United States)

    Kaladhar, K; Renz, H; Sharma, C P

    2015-04-01

    Exploring drug molecules for material design, to harness concepts of nano-anisotropy and ligand-receptor interactions, are rather elusive. The aim of this study is to demonstrate the bottom-up design of a single-step and bio-interactive polymeric surface coating, based on drug based pendant polymer. This can be applied on to polystyrene (PS) substrates, to suppress macrophage adhesion and spreading. The drug molecule is used in this coating for two purposes. The first one is drug as a "pendant" group, to produce nano-anisotropic properties that can enable adhesion of the coatings to the substrate. The second purpose is to use the drug as a "ligand", to produce ligand-receptor interaction, between the bound ligand and receptors of albumin, to develop a self-albumin coat over the surface, by the preferential binding of albumin in biological environment, to reduce macrophage adhesion. Our in silico studies show that, diclofenac (DIC) is an ideal drug based "ligand" for albumin. This can also act as a "pendant" group with planar aryl groups. The combination of these two factors can help to harness, both nano-anisotropic properties and biological functions to the polymeric coating. Further, the drug, diclofenac (DIC) is immobilized to the polyvinyl alcohol (PVA), to develop the pendant polymer (PVA-DIC). The interaction of bound DIC with the albumin is a ligand-receptor based interaction, as per the studies by circular dichroism, differential scanning calorimetry, and SDS-PAGE. The non-polar π-π* interactions are regulating; the interactions between PVA bound DIC-DIC interactions, leading to "nano-anisotropic condensation" to form distinct "nano-anisotropic segments" inside the polymeric coating. This is evident from, the thermo-responsiveness and uniform size of nanoparticles, as well as regular roughness in the surface coating, with similar properties as that of nanoparticles. In addition, the hydrophobic DIC-polystyrene (PS) interactions, between the PVA

  16. Methods for generation of reporter phages and immobilization of active bacteriophages on a polymer surface

    Science.gov (United States)

    Morgan, Mark Thomas (Inventor); Kothapalli, Aparna (Inventor); Applegate, Bruce Michael (Inventor); Perry, Lynda Louise (Inventor)

    2012-01-01

    Novel reporter bacteriophages are provided. Provided are compositions and methods that allow bacteriophages that are used for specific detection or killing of E. coli 0157:H7 to be propagated in nonpathogenic E. coli, thereby eliminating the safety and security risks of propagation in E. coli 0157:H7. Provided are compositions and methods for attaching active bacteriophages to the surface of a polymer in order to kill target bacteria with which the phage comes into contact. Provided are modified bacteriophages immobilized to a surface, which capture E. coli 0157:H7 and cause the captured cells to emit light or fluorescence, allowing detection of the bacteria in a sample.

  17. High density gold nanoparticles immobilized on surface via plasma deposited APTES film for decomposing organic compounds in microchannels

    Science.gov (United States)

    Rao, Xi; Guyon, Cédric; Ognier, Stephanie; Da Silva, Bradley; Chu, Chenglin; Tatoulian, Michaël; Hassan, Ali Abou

    2018-05-01

    Immobilization of colloidal particles (e.g. gold nanoparticles (AuNps)) on the inner surface of micro-/nano- channels has received a great interest for catalysis. A novel catalytic ozonation setup using a gold-immobilized microchannel reactor was developed in this work. To anchor AuNps, (3-aminopropyl) triethoxysilane (APTES) with functional amine groups was deposited using plasma enhanced chemical vapor deposition (PECVD) process. The results clearly evidenced that PECVD processing exhibited relatively high efficiency for grafting amine groups and further immobilizing AuNPs. The catalytic activity of gold immobilized microchannel was evaluated by pyruvic acid ozonation. The decomposition rate calculated from High Performance Liquid Chromatography (HPLC) indicated a much better catalytic performance of gold in microchannel than that in batch. The results confirmed immobilizing gold nanoparticles on plasma deposited APTES for preparing catalytic microreactors is promising for the wastewater treatment in the future.

  18. Surface functionalization of chitosan-coated magnetic nanoparticles for covalent immobilization of yeast alcohol dehydrogenase from Saccharomyces cerevisiae

    Science.gov (United States)

    Li, Gui-yin; Zhou, Zhi-de; Li, Yuan-jian; Huang, Ke-long; Zhong, Ming

    2010-12-01

    A novel and efficient immobilization of yeast alcohol dehydrogenase (YADH, EC1.1.1.1) from Saccharomyces cerevisiae has been developed by using the surface functionalization of chitosan-coated magnetic nanoparticles (Fe 3O 4/KCTS) as support. The magnetic Fe 3O 4/KCTS nanoparticles were prepared by binding chitosan alpha-ketoglutaric acid (KCTS) onto the surface of magnetic Fe 3O 4 nanoparticles. Later, covalent immobilization of YADH was attempted onto the Fe 3O 4/KCTS nanoparticles. The effect of various preparation conditions on the immobilized YADH process such as immobilization time, enzyme concentration and pH was investigated. The influence of pH and temperature on the activity of the free and immobilized YADH using phenylglyoxylic acid as substrate has also been studied. The optimum reaction temperature and pH value for the enzymatic conversion catalyzed by the immobilized YADH were 30 °C and 7.4, respectively. Compared to the free enzyme, the immobilized YADH retained 65% of its original activity and exhibited significant thermal stability and good durability.

  19. Surface Modification of Polypropylene Microporous Membrane by Atmospheric-Pressure Plasma Immobilization of N,N-dimethylamino Ethyl Methacrylate

    International Nuclear Information System (INIS)

    Zhong Shaofeng

    2010-01-01

    Surface modification of polypropylene microporous membrane (PPMM) was performed by atmospheric pressure dielectric barrier discharge plasma immobilization of N,N-dimethylamino ethyl methacrylate (DMAEMA). Structural and morphological changes on the membrane surface were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscopy (FE-SEM). Water contact angles of the membrane surfaces were also measured by the sessile drop method. Results reveal that both the plasma-treating conditions and the adsorbed DMAEMA amount have remarkable effects on the immobilization degree of DMAEMA. Peroxide determination by 1,1-diphenyl-2-picrvlhydrazyl (DPPH) method verifies the exsistence of radicals induced by plasma, which activize the immobilization reaction. Pure water contact angle on the membrane surface decreased with the increase of DMAEMA immobilization degree, which indicates an enhanced hydrophilicity for the modified membranes. The effects of immobilization degrees on pure water fluxes were also measured. It is shown that pure water fluxes first increased with immobilization degree and then decreased. Finally, permeation of bovine serum albumin (BSA) and lysozyme solution were measured to evaluate the antifouling property of the DMAEMA-modified membranes, from which it is shown that both hydrophilicity and electrostatic repulsion are beneficial for membrane antifouling.

  20. Strategies For Immobilization Of Bioactive Organic Molecules On Titanium Implant Surfaces – A Review

    Directory of Open Access Journals (Sweden)

    Panayotov Ivan V.

    2015-03-01

    Full Text Available Numerous approaches have been used to improve the tissue-implant interface of titanium (Ti and titanium alloy (Ti6Al4V. They all aim at increasing cell migration and attachment to the metal, preventing unspecific protein adsorption and improving post-implantation healing process. Promising methods for titanium and titanium alloy surface modification are based on the immobilization of biologically active organic molecules. New and interesting biochemical approaches to such surface modification include layer-by-layer deposition of polyelectrolyte films, phage display-selected surface binding peptides and self-assembled DNA monolayer systems. The present review summarizes the scientific information about these methods, which are at in vitro or in vivo development stages, and hopes to promote their future application in dental implantology and in oral and maxillofacial surgery.

  1. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    Science.gov (United States)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-11-01

    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from groundwater into surface water in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and surface water, we investigated Fe(II) oxidation kinetics and P immobilization processes. The oxidation rate inferred from our field measurements closely agreed with the general rate law for abiotic oxidation of Fe(II) by O2. Seasonal changes in climatic conditions affected the Fe(II) oxidation process. Lower pH and lower temperatures in winter (compared to summer) resulted in low Fe oxidation rates. After exfiltration to the surface water, it took a couple of days to more than a week before complete oxidation of Fe(II) is reached. In summer time, Fe oxidation rates were much higher. The Fe concentrations in the exfiltrated groundwater were low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into a ditch. While the Fe oxidation rates reduce drastically from summer to winter, P concentrations remained high in the groundwater and an order of magnitude lower in the surface water throughout the year. This study shows very fast immobilization of dissolved P during the initial stage of the Fe(II) oxidation process which results in P-depleted water before Fe(II) is completely depleted. This cannot be explained by surface complexation of phosphate to freshly formed Fe-oxyhydroxides but indicates the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at redox gradients

  2. Surface functionalization of polyethylene via covalent immobilization of O-stearoyl-chitosan

    International Nuclear Information System (INIS)

    Xin, Zhirong; Hou, Juan; Ding, Jiaotong; Yang, Zongfeng; Yan, Shunjie; Liu, Chan

    2013-01-01

    When used in blood-contacting field, the hemocompatibility of polyethylene (PE) needs further to be improved. In this article, O-stearoyl-chitosans (OSC) with different esterification degrees were successfully prepared via changing the ratios of chitosan and stearoyl chloride for decreasing the cationic and hydrogen bond strength, thus improving the solubility of chitosan. The PE film was grafted with carboxyl groups of acrylic acid (AA) (PE-g-PAA) by means of O 2 plasma pre-treatment and UV-induced graft polymerization, and then PE-g-PAA was used for covalent immobilization of OSC. The above surface modification was confirmed by ATR-FTIR and XPS. Effect of the UV-irradiated graft polymerization parameters, i.e., the discharge power, the plasma pretreatment time, the UV irradiation time and the monomer concentration on the grafting density of AA was investigated. Relative to the value of about 107° for the virgin sample, the water contact angle (WCA) of the PAA-grafted film was about 50°. After the further immobilization of OSC onto the PAA-grafted film, the strength of negative charge of the PAA-grafted surface was decreased by the electropositive OSC, thus presenting a WCA value of about 62° and the excellent performance of anti-platelet adhesion with respect to the virgin and PAA-grafted samples.

  3. Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

    Science.gov (United States)

    Afshari, Esmail; Mazinani, Saeedeh; Ranaei-Siadat, Seyed-Omid; Ghomi, Hamid

    2016-11-01

    Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO2, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

  4. Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

    International Nuclear Information System (INIS)

    Afshari, Esmail; Mazinani, Saeedeh; Ranaei-Siadat, Seyed-Omid; Ghomi, Hamid

    2016-01-01

    Highlights: • We fabricated polyvinyl alcohol/malonic acid nanofibers using electrospinning. • The surface nanofibers were modified by gaseous (air, nitrogen, CO_2 and argon) dielectric barrier discharge. • Among them, air plasma had the most significant effect on glucose oxidase immobilization. • Chemical analysis showed that after modification of nanofibers by air plasma, the carboxyl group increased. • After air plasma treatment, reusability and storage stability of glucose oxidase immobilized on nanofibers improved. - Abstract: Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO_2, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

  5. Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Afshari, Esmail, E-mail: e.afshari@mail.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Mazinani, Saeedeh [Amirkabir Nanotechnology Research Institute (ANTRI), Amirkabir University of Technology, 15875-4413, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of)

    2016-11-01

    Highlights: • We fabricated polyvinyl alcohol/malonic acid nanofibers using electrospinning. • The surface nanofibers were modified by gaseous (air, nitrogen, CO{sub 2} and argon) dielectric barrier discharge. • Among them, air plasma had the most significant effect on glucose oxidase immobilization. • Chemical analysis showed that after modification of nanofibers by air plasma, the carboxyl group increased. • After air plasma treatment, reusability and storage stability of glucose oxidase immobilized on nanofibers improved. - Abstract: Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO{sub 2}, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

  6. Plasma immersion ion implantation of polyurethane shape memory polymer: Surface properties and protein immobilization

    Science.gov (United States)

    Cheng, Xinying; Kondyurin, Alexey; Bao, Shisan; Bilek, Marcela M. M.; Ye, Lin

    2017-09-01

    Polyurethane-type shape memory polymers (SMPU) are promising biomedical implant materials due to their ability to recover to a predetermined shape from a temporary shape induced by thermal activation close to human body temperature and their advantageous mechanical properties including large recovery strains and low recovery stresses. Plasma Immersion Ion Implantation (PIII) is a surface modification process using energetic ions that generates radicals in polymer surfaces leading to carbonisation and oxidation and the ability to covalently immobilise proteins without the need for wet chemistry. Here we show that PIII treatment of SMPU significantly enhances its bioactivity making SMPU suitable for applications in permanent implantable biomedical devices. Scanning Electron Microscopy (SEM), contact angle measurements, surface energy measurements, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterise the PIII modified surface, including its after treatment aging kinetics and its capability to covalently immobilise protein directly from solution. The results show a substantial improvement in wettability and dramatic changes of surface chemical composition dependent on treatment duration, due to the generation of radicals and subsequent oxidation. The SMPU surface, PIII treated for 200s, achieved a saturated level of covalently immobilized protein indicating that a full monolayer coverage was achieved. We conclude that PIII is a promising and efficient surface modification method to enhance the biocompatibility of SMPU for use in medical applications that demand bioactivity for tissue integration and stability in vivo.

  7. Use of activated carbon as a support medium for H{sub 2}S biofiltration and effect of bacterial immobilization on available pore surface

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Y.L.; Yan, R.; Chen, X.G.; Geng, A.L.; Liang, D.T.; Koe, L.C.C. [Institute of Environmental Science and Engineering, Nanyang Technological Univ., Singapore (Singapore); Gould, W.D. [Environmental Lab., CANMET, Natural Resources Canada, Ottawa, ON (Canada)

    2004-12-01

    The use of support media for the immobilization of micro-organisms widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In this study, activated carbon is used as a support medium for the immobilization of microorganisms enriched from municipal sewage activated sludge to remove gas-phase hydrogen sulfide (H{sub 2}S), a major odorous component of waste gas from sewage treatment plants. A series of designed experiments is used to examine the effect on bacteria-immobilized activated carbon (termed ''biocarbon'') due to physical adsorption, chemical reaction and microbial degradation in the overall removal of H{sub 2}S. H{sub 2}S breakthrough tests are conducted with various samples, including micro-immobilized carbon and Teflon discs, salts-medium-washed carbon, and ultra-pure water-washed carbon. The results show a higher removal capacity for the microbe-immobilized activated carbon compared with the activated carbon control in a batch biofilter column. The increase in removal capacity is attributed to the role played by the immobilized micro-organisms in metabolizing adsorbed sulfur and sulfur compounds on the biocarbon, hence releasing the adsorption sites for further H{sub 2}S uptake. The advantage for activated carbon serving as the support medium is to adsorb a high initial concentration of substrate and progressively release this for microbial degradation, hence acting as a buffer for the microorganisms. Results obtained from surface area and pore size distribution analyses of the biocarbon show a correlation between the available surface area and pore volume with the extent of microbial immobilization and H{sub 2}S uptake. The depletion of surface area and pore volume is seen as one of the factors which cause the onset of column breakthrough. Microbial growth retardation is due to the accumulation of metabolic products (i.e., sulfuric acid); and a lack of water and

  8. Soluble and immobilized graphene oxide activates complement system differently dependent on surface oxidation state

    DEFF Research Database (Denmark)

    Wibroe, Peter Popp; Petersen, Søren Vermehren; Bovet, Nicolas Emile

    2016-01-01

    on two related elements of innate immunity: the complement system and interleukin-6 (IL-6) release in human blood. In solution, there was a decrease in GO-mediated complement activation with decreasing surface oxygen content (and altered oxygen functionality), whereas with immobilized GO complement...... response were reversed and increased with decreasing oxygen content. GO solutions, at concentrations below complement activating threshold, did not induce IL-6 release from human blood leukocytes, and further dampened lipopolysaccharide-induced IL-6 release in the whole blood. The latter effect became more...... profound with GO's having higher oxygen content. This protective role of GO solutions, however, disappeared at higher concentrations above complement-activating threshold. We discuss these results in relation to GO surface structure and properties, and implications for local administration and development...

  9. Surface Redox Chemistry of Immobilized Nanodiamond: Effects of Particle Size and Electrochemical Environment

    Science.gov (United States)

    Gupta, S.; McDonald, B.; Carrizosa, S. B.

    2017-07-01

    The size of the diamond particle is tailored to nanoscale (nanodiamond, ND), and the ND surface is engineered targeting specific (electrochemical and biological) applications. In this work, we investigated the complex surface redox chemistry of immobilized ND layer on conductive boron-doped diamond electrode with a broad experimental parameter space such as particle size (nano versus micron), scan rate, pH (cationic/acidic versus anionic/basic), electrolyte KCl concentration (four orders of magnitude), and redox agents (neutral and ionic). We reported on the significant enhancement of ionic currents while recording reversible oxidation of neutral ferrocene methanol (FcMeOH) by almost one order of magnitude than traditional potassium ferricyanide (K3Fe(CN)6) redox agent. The current enhancement is inversely related to ND particle diameter in the following order: 1 μm << 1000 nm < 100 nm < 10 nm ≤ 5 nm < 2 nm. We attribute the current enhancement to concurrent electrocatalytic processes, i.e. the electron transfer between redox probes and electroactive surface functional (e.g. hydroxyl, carboxyl, epoxy) moieties and the electron transfer mediated by adsorbed FcMeOH+ (or Fe(CN) 6 3+ ) ions onto ND surface. The first process is pH dependent since it depends upon ND surface functionalities for which the electron transfer is coupled to proton transfer. The adsorption mediated process is observed most apparently at slower scan rates owing to self-exchange between adsorbed FcMeOH+ ions and FcMeOH redox agent molecules in diffusion-limited bulk electrolyte solution. Alternatively, it is hypothesized that the surface functionality and defect sites ( sp 2-bonded C shell and unsaturated bonds) give rise to surface electronic states with energies within the band gap (midgap states) in undoped ND. These surface states serve as electron donors (and acceptors) depending upon their bonding (and antibonding) character and, therefore, they can support electrocatalytic redox

  10. Iron oxidation kinetics and phosphorus immobilization at the groundwater-surface water interface

    Science.gov (United States)

    van der Grift, Bas; Rozemeijer, Joachim; Griffioen, Jasper; van der Velde, Ype

    2014-05-01

    Eutrophication of freshwater environments following diffuse nutrient loads is a widely recognized water quality problem in catchments. Fluxes of non-point P sources to surface waters originate from surface runoff and flow from soil water and groundwater into surface water. The availability of P in surface waters is controlled strongly by biogeochemical nutrient cycling processes at the soil-water interface. The mechanisms and rates of the iron oxidation process with associated binding of phosphate during exfiltration of anaerobic Fe(II) bearing groundwater are among the key unknowns in P retention processes in surface waters in delta areas where the shallow groundwater is typically pH-neutral to slightly acid, anoxic, iron-rich. We developed an experimental field set-up to study the dynamics in Fe(II) oxidation and mechanisms of P immobilization at the groundwater-surface water interface in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. The exfiltrating groundwater was captured in in-stream reservoirs constructed in the ditch. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and ditch water, we quantified Fe(II) oxidation kinetics and P immobilization processes across the seasons. This study showed that seasonal changes in climatic conditions affect the Fe(II) oxidation process. In winter time the dissolved iron concentrations in the in-stream reservoirs reached the levels of the anaerobic groundwater. In summer time, the dissolved iron concentrations of the water in the reservoirs are low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into the reservoirs. Higher discharges, lower temperatures and lower pH of the exfiltrated groundwater in winter compared to summer shifts the location of the redox transition zone

  11. In situ immobilization on the silica gel surface and adsorption capacity of polymer-based azobenzene on toxic metal ions

    Science.gov (United States)

    Savchenko, Irina; Yanovska, Elina; Sternik, Dariusz; Kychkyruk, Olga; Ol'khovik, Lidiya; Polonska, Yana

    2018-03-01

    In situ immobilization of poly[(4-methacryloyloxy-(4'-carboxy)azobenzene] on silica gel surface has been performed by radical polymerization of monomer. The fact of polymer immobilization is confirmed by IR spectroscopy. TG and DSC-MS analysis showed that the mass of the immobilized polymer was 10.61%. The SEM-microphotograph-synthesized composite analysis showed that the immobilized polymer on the silica gel surface is placed in the form of fibers. It has been found that the synthesized composite exhibits the sorption ability in terms of microquantities of Cu(II), Cd(II), Pb(II), Mn(II) and Fe(III) ions in a neutral aqueous medium. The quantitative sorption of microquantities of Pb(II) and Fe(III) ions has been recorded. It has been found that immobilization of the silica gel surface leads to an increase in its sorption capacitance for Fe(III), Cu(II) and Pb(II) ions by half.

  12. Screening hydroxyapatite for cadmium and lead immobilization in aqueous solution and contaminated soil: The role of surface area.

    Science.gov (United States)

    Li, Hongying; Guo, Xisheng; Ye, Xinxin

    2017-02-01

    Hydroxyapatite (HAP) has been widely used to immobilize many cationic metals in water and soils. The specific reason why an increase in the surface area of HAP enhances cadmium (Cd) uptake, but has no effect on lead (Pb) uptake, is not clear. The aim of this study was to determine the factors causing the differences in sorption behavior between Cd and Pb by evaluating HAPs with different surface areas. We synthesized HAPs with two different surface areas, which were characterized by X-ray diffraction, N 2 adsorption, and scanning electron microscopy, and then evaluated them as sorbents for Cd and Pb removal by testing in single and binary systems. The sorption capacity of large surface area HAP (1.85mmol/g) for Cd in the single-metal system was higher than that of small surface area HAP (0.64mmol/g), but there were no differences between single- and binary-metal solutions containing Pb. After the Cd experiments, the HAP retained a stable structure and intact morphology, which promotes the accessibility of reactive sites for Cd. However, a newly formed precipitate covered the surface and blocked the channels in the presence of Pb, which reduced the number of potential adsorption sites on HAP for Cd and Pb. Remediation experiments using Cd- and Pb-contaminated soil produced similar results to the solution tests. These results indicate that alterations of the structure and morphology during the reaction is an important factor influencing metal sorption to HAP. Copyright © 2016. Published by Elsevier B.V.

  13. Nanopolyaniline as immobilization template for signal enhancement of surface plasmon resonance biosensor - A preliminary study

    Science.gov (United States)

    Kamarun, Dzaraini; Abdul Azem, Nor Hazirah Kamel; Sarijo, Siti Halimah; Mohd, Ahmad Faiza; Abdullah @ Mohd Noor, Mashita

    2012-07-01

    A technique for the enhancement of Surface Plasmon Resonance (SPR) signal for sensing biomolecular interactions is described. Polyaniline (PANI) of particle size in the range of 1 to 15 nm was synthesized and used as the template for the immobilization of protein molecules. Biomolecular interactions of unbound and PANI-bound proteins with antibody molecules were SPR-monitored using a model system comprising of Bovine Serum Albumin (BSA) and anti BSA. A 7-fold increased in the signal was recorded from interactions of the PANI-bound BSA with anti BSA compared to the interactions of its unbound counterpart. This preliminary observation provides new avenue in immunosensor technology for improving the detection sensitivity of SPR biosensor; and thereby increasing the lower detection limit of biomolecules.

  14. DNA immobilization and detection on cellulose paper using a surface grown cationic polymer via ATRP.

    Science.gov (United States)

    Aied, Ahmed; Zheng, Yu; Pandit, Abhay; Wang, Wenxin

    2012-02-01

    Cationic polymers with various structures have been widely investigated in the areas of medical diagnostics and molecular biology because of their unique binding properties and capability to interact with biological molecules in complex biological environments. In this work, we report the grafting of a linear cationic polymer from an atom transfer radical polymerization (ATRP) initiator bound to cellulose paper surface. We show successful binding of ATRP initiator onto cellulose paper and grafting of polymer chains from the immobilized initiator with ATRP. The cellulose paper grafted polymer was used in combination with PicoGreen (PG) to demonstrate detection of nucleic acids in the nanogram range in homogeneous solution and in a biological sample (serum). The results showed specific identification of hybridized DNA after addition of PG in both solutions.

  15. Decolorization of textile dye RB19 using volcanic rock matrix immobilized Bacillus thuringiensis cells with surface displayed laccase.

    Science.gov (United States)

    Wan, Juan; Sun, Xiaowen; Liu, Cheng; Tang, Mengjun; Li, Lin; Ni, Hong

    2017-06-01

    A triplicate volcanic rock matrix-Bacillus thuringiensis-laccase WlacD (VRMs-Bt-WlacD) dye decolorization system was developed. WlacD was displayed on the B. thuringiensis MB174 cell surface to prepare a whole-cell laccase biocatalyst by using two repeat N-terminal domains of autolysin Mbg (Mbgn) 2 as the anchoring motif. Immunofluorescence microscopic assays confirmed that the fusion protein (Mbgn) 2 -WlacD was anchored on the surface of the recombinant B. thuringiensis MB174. After optimization by a single factor test, L 9 (3 4 )-orthogonal test, Plackett-Burman test, steepest ascent method, and Box-Behnken response surface methodology, the whole-cell specific laccase activity of B. thuringiensis MB174 was improved to 555.2 U L -1 , which was 2.25 times than that of the primary culture condition. Optimized B. thuringiensis MB174 cells were further adsorbed by VRMs to prepare VRMs-Bt-WlacD, an immobilized whole-cell laccase biocatalyst. Decolorization capacity of as-prepared VRMs-Bt-WlacD toward an initial concentration of 500 mg L -1 of an textile dye reactive blue 19 (RB19) aqueous solution reached 72.36% at a solid-to-liquid ratio of 10 g-100 mL. Repeated decolorization-activation operations showed the high decolorization capacity of VRMs-Bt-WlacD and have the potential for large-scale or continuous operations.

  16. Cystamine immobilization on TiO2 film surfaces and the influence on inhibition of collagen-induced platelet activation

    International Nuclear Information System (INIS)

    Zhou Yujuan; Weng Yajun; Zhang Liping; Jing Fengjuan; Huang Nan; Chen Junying

    2011-01-01

    Poor haemocompatibility is a main issue of artificial cardiovascular materials in clinical application. Nitric oxide (NO), produced by vascular endothelial cells, is a well known inhibitor of platelet adhesion and activation. Thus, NO-releasing biomaterials are beneficial for improving haemocompatibility of blood-contacting biomedical devices. In this paper, a novel method was developed for enhancement of haemocompatibility by exploiting endogenous NO donors. TiO 2 films were firstly synthesized on Si (1 0 0) wafers via unbalanced magnetron sputtering technology, and then polydopamine was grafted on TiO 2 films and used as a linker for further immobilization of cystamine. The obtained surfaces were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. NO generation is evaluated by saville-griess reagents, and it shows that cystamine immobilized samples are able to catalytically generate NO by decomposing endogenous S-nitrosothiols (RSNO). In vitro platelet adhesion results reveal that cystamine modified surfaces can inhibit collagen-induced platelet activation. ELISA analysis reveals that cGMP in platelets obviously increases on cystamine immobilized surface, which suggests the reducing of platelet activation is through NO/cGMP signal channel. It can be concluded that cystamine immobilized surface shows better blood compatibility by catalyzing NO release from the endogenous NO donor. It may be a promising method for improvement of haemocompatibility of blood-contacting implants.

  17. Polysialic acid immobilized on silanized glass surfaces: a test case for its use as a biomaterial for nerve regeneration.

    Science.gov (United States)

    Steinhaus, Stephanie; Stark, Yvonne; Bruns, Stephanie; Haile, Yohannes; Scheper, Thomas; Grothe, Claudia; Behrens, Peter

    2010-04-01

    The immobilization of polysialic acid (polySia) on glass substrates has been investigated with regard to the applicability of this polysaccharide as a novel, biocompatible and bioresorbable material for tissue engineering, especially with regard to its use in nerve regeneration. PolySia, a homopolymer of alpha-2,8-linked sialic acid, is involved in post-translational modification of the neural cell adhesion molecule (NCAM). The degradation of polySia can be controlled which makes it an interesting material for coating and for scaffold construction in tissue engineering. Here, we describe the immobilization of polySia on glass surfaces via an epoxysilane linker. Whereas glass surfaces will not actually be used in nerve regeneration scaffolds, they provide a simple and efficient means for testing various methods for the investigation of immobilized polySia. The modified surfaces were investigated with contact angle measurements and the quantity of immobilized polySia was examined by the thiobarbituric acid assay and a specific polySia-ELISA. The interactions between the polySia-modified surface and immortalized Schwann cells were evaluated via cell adhesion and cell viability assays. The results show that polySia can be immobilized on glass surfaces via the epoxysilane linker and that surface-bound polySia has no toxic effects on Schwann cells. Therefore, as a key substance in the development of vertebrates and as a favourable substrate for the cultivation of Schwann cells, it offers interesting features for the use in nerve guidance tubes for treatment of peripheral nerve injuries.

  18. Synthesis and surface immobilization of antibacterial hybrid silver-poly(l-lactide) nanoparticles

    International Nuclear Information System (INIS)

    Taheri, Shima; Majewski, Peter; Vasilev, Krasimir; Baier, Grit; Landfester, Katharina; Barton, Mary; Förch, Renate

    2014-01-01

    Infections associated with medical devices are a substantial healthcare problem. Consequently, there has been increasing research and technological efforts directed toward the development of coatings that are capable of preventing bacterial colonization of the device surface. Herein, we report on novel hybrid silver loaded poly(L-lactic acid) nanoparticles (PLLA-AgNPs) with narrowly distributed sizes (17 ± 3 nm) prepared using a combination of solvent evaporation and mini-emulsion technology. These particles were then immobilized onto solid surfaces premodified with a thin layer of allylamine plasma polymer (AApp). The antibacterial efficacy of the PLLA-AgNPs nanoparticles was studied in vitro against both gram-positive (Staphylococcus epidermidis) and gram-negative (Escherichia coli) bacteria. The minimal inhibitory concentration values against Staphylococcus epidermidis and Escherichia coli were 0.610 and 1.156 μg · mL −1 , respectively. The capacity of the prepared coatings to prevent bacterial surface colonization was assessed in the presence of Staphylococcus epidermidis, which is a strong biofilm former that causes substantial problems with medical device associated infections. The level of inhibition of bacterial growth was 98%. The substrate independent nature and the high antibacterial efficacy of coatings presented in this study may offer new alternatives for antibacterial coatings for medical devices. (paper)

  19. Synthesis and surface immobilization of antibacterial hybrid silver-poly(l-lactide) nanoparticles

    Science.gov (United States)

    Taheri, Shima; Baier, Grit; Majewski, Peter; Barton, Mary; Förch, Renate; Landfester, Katharina; Vasilev, Krasimir

    2014-08-01

    Infections associated with medical devices are a substantial healthcare problem. Consequently, there has been increasing research and technological efforts directed toward the development of coatings that are capable of preventing bacterial colonization of the device surface. Herein, we report on novel hybrid silver loaded poly(L-lactic acid) nanoparticles (PLLA-AgNPs) with narrowly distributed sizes (17 ± 3 nm) prepared using a combination of solvent evaporation and mini-emulsion technology. These particles were then immobilized onto solid surfaces premodified with a thin layer of allylamine plasma polymer (AApp). The antibacterial efficacy of the PLLA-AgNPs nanoparticles was studied in vitro against both gram-positive (Staphylococcus epidermidis) and gram-negative (Escherichia coli) bacteria. The minimal inhibitory concentration values against Staphylococcus epidermidis and Escherichia coli were 0.610 and 1.156 μg · mL-1, respectively. The capacity of the prepared coatings to prevent bacterial surface colonization was assessed in the presence of Staphylococcus epidermidis, which is a strong biofilm former that causes substantial problems with medical device associated infections. The level of inhibition of bacterial growth was 98%. The substrate independent nature and the high antibacterial efficacy of coatings presented in this study may offer new alternatives for antibacterial coatings for medical devices.

  20. Decolorization of industrial synthetic dyes using engineered Pseudomonas putida cells with surface-immobilized bacterial laccase

    Directory of Open Access Journals (Sweden)

    Wang Wei

    2012-06-01

    Full Text Available Abstract Background Microbial laccases are highly useful in textile effluent dye biodegradation. However, the bioavailability of cellularly expressed or purified laccases in continuous operations is usually limited by mass transfer impediment or enzyme regeneration difficulty. Therefore, this study develops a regenerable bacterial surface-displaying system for industrial synthetic dye decolorization, and evaluates its effects on independent and continuous operations. Results A bacterial laccase (WlacD was engineered onto the cell surface of the solvent-tolerant bacterium Pseudomonas putida to construct a whole-cell biocatalyst. Ice nucleation protein (InaQ anchor was employed, and the ability of 1 to 3 tandemly aligned N-terminal repeats to direct WlacD display were compared. Immobilized WlacD was determined to be surface-displayed in functional form using Western blot analysis, immunofluorescence microscopy, flow cytometry, and whole-cell enzymatic activity assay. Engineered P. putida cells were then applied to decolorize the anthraquinone dye Acid Green (AG 25 and diazo-dye Acid Red (AR 18. The results showed that decolorization of both dyes is Cu2+- and mediator-independent, with an optimum temperature of 35°C and pH of 3.0, and can be stably performed across a temperature range of 15°C to 45°C. A high activity toward AG25 (1 g/l with relative decolorization values of 91.2% (3 h and 97.1% (18 h, as well as high activity to AR18 (1 g/l by 80.5% (3 h and 89.0% (18 h, was recorded. The engineered system exhibited a comparably high activity compared with those of separate dyes in a continuous three-round shake-flask decolorization of AG25/AR18 mixed dye (each 1 g/l. No significant decline in decolorization efficacy was noted during first two-rounds but reaction equilibriums were elongated, and the residual laccase activity eventually decreased to low levels. However, the decolorizing capacity of the system was easily retrieved

  1. Antibacterial activity of contact lenses bearing surface-immobilized layers of intact liposomes loaded with levofloxacin.

    Science.gov (United States)

    Danion, Anne; Arsenault, Isabelle; Vermette, Patrick

    2007-09-01

    In vitro methods to evaluate antibacterial activity were used with contact lenses bearing levofloxacin-loaded liposomes developed for the prevention and treatment of bacterial ocular infections such as keratitis. Levofloxacin was incorporated into liposomes before these intact liposomes were immobilized onto the surfaces of soft contact lenses using a multilayer immobilization strategy. The release of levofloxacin from contact lenses bearing 2, 5, and 10 layers of liposomes into a saline buffer at 37 degrees C was monitored by fluorescence. The levofloxacin release, as a function of time, was described by a mechanism taking into account two independent first-order kinetic models. The total release of levofloxacin from the contact lenses was completed within 6 days. The release of levofloxacin from contact lenses bearing 10 layers of liposomes and subsequently soaked overnight in a levofloxacin solution was also studied and compare to that of dried contact lenses without any chemical modification rehydrated in a levofloxacin solution. The antibacterial activity of the liposome-coated contact lenses against Staphylococcus aureus was evaluated by measuring (i) the diameters of the inhibition zone on an agar plate and (ii) the optical density using a broth assay. The liposome-coated lenses showed an antibacterial activity both on agar and in broth following 24 h. When initial bacteria inocula were equal or below 10(6) CFU/mL, all the bacteria were inhibited within 2 h. When using initial bacteria inocula of 10(8) CFU/mL, an initial burst release provided by soaking the liposomal lenses was required for the first hours to inhibit bacteria growth. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

  2. Three Dimensional Immobilization of Beta-Galactosidase on a Silicon Surface (Preprint)

    National Research Council Canada - National Science Library

    Luckarift, Heather R; Betancor, Lorena; Spain, Jim C

    2006-01-01

    .... The entrapment of enzymes within silica-based nanospheres formed through silicification reactions provides high loading capacities for enzyme immobilization, resulting in high volumetric activity...

  3. Protein immobilization on the surface of liposomes via carbodiimide activation in the presence of N-hydroxysulfosuccinimide.

    Science.gov (United States)

    Bogdanov, A A; Klibanov, A L; Torchilin, V P

    1988-04-25

    A method of the covalent immobilization of proteins on the surface of liposomes, containing 10% (by mol) of N-glutaryl phosphatidylethanolamine, is described. Carboxylic groups of liposomal N-glutaryl phosphatidylethanolamine were activated in the presence of water-soluble carbodiimide and N-hydroxysulfosuccinimide and reacted subsequently with protein amino groups. The liposome-protein conjugates formed contained up to 5 x 10(-4) mol protein/mol lipid. Lectins (RCA1 and WGA) upon immobilization on liposomes retained saccharide specificity and the ability to agglutinate red blood cells. The immobilization of mouse monoclonal IgG in a ratio of 3.5 x 10(-4) mol IgG/mol lipid was achieved. The liposome activation in the absence of N-hydroxysulfosuccinimide resulted in a 2-fold decrease of protein coupling yields.

  4. Horseradish peroxidase immobilized on copper surfaces and applications in selective electrocatalysis of p-dihydroxybenzene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chuntao, E-mail: tsyj1992@126.com [Department of Chemistry, Taiyuan Normal University, Taiyuan 030031 (China); Institute of Energy and Environmental Electrochemistry, Taiyuan Normal University, Taiyuan 030031 (China); Luo, Xiaoxiao [Department of Natural Science, Michigan State University, MI 48823,USA (United States); Jia, Zehui [Department of Chemistry, Taiyuan Normal University, Taiyuan 030031 (China); Institute of Energy and Environmental Electrochemistry, Taiyuan Normal University, Taiyuan 030031 (China); Shi, Qinghua; Zhu, Ritao [Department of Chemistry, Taiyuan Normal University, Taiyuan 030031 (China)

    2017-06-01

    Abstract: Horseradish Peroxidase (HRP) was immobilized on copper surfaces with the linker of L-Cysteine (L-Cys) self-assembled films to form Cu/L-Cys/HRP electrodes. The activity of HRP can be preserved by the Cu/L-Cys self-assembled films. The Cu/L-Cys/HRP electrodes can be used for the selective electrocatalytic oxidase of p-dihydroxybenzen in absent of H{sub 2}O{sub 2}. The optimum pH for electrocatalyzing p-dihydroxybenzen was 5.5 or 7.0, which corresponds to the isoelectric points of L-Cys and HRP, respectively. X-ray photoelectron spectroscopy (XPS) provided the evidence that L-Cys linked with Cu surface by the Cu− S bond. Fourier transform infrared spectroscopy (FTIR) analyses indicated that aromatic plane of p-dihydroxybenzen was connected parallel to porphyrin ring of heme in HRP. Quantum chemical calculation of density functional theory (DFT) revealed that symmetry of molecular structure and minimum space steric hindrance for p-dihydroxybenzen were benefit to combination with HRP. Moreover, the lowest energy of LUMO and most negative charges of oxygen atom on hydroxyl group of p-dihydroxybenzen were advantage to lose the hydrogen atom of hydroxyl group to be oxided.

  5. Immobilization of oligonucleotide probes on silicon surfaces using biotin–streptavidin system examined with microscopic and spectroscopic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Awsiuk, K., E-mail: kamil.awsiuk@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, Kraków 30-059 (Poland); Rysz, J. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, Kraków 30-059 (Poland); Petrou, P. [Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, End Patriarchou Gregoriou Str., Aghia Paraskevi 15310 (Greece); Budkowski, A. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, Kraków 30-059 (Poland); Bernasik, A. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30, Kraków 30-059 (Poland); Kakabakos, S. [Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, End Patriarchou Gregoriou Str., Aghia Paraskevi 15310 (Greece); Marzec, M.M. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30, Kraków 30-059 (Poland); Raptis, I. [Institute for Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems, NCSR “Demokritos”, End Patriarchou Gregoriou Str., Aghia Paraskevi 15310 (Greece)

    2014-01-30

    To immobilize effectively oligonucleotide probes on SiO{sub 2} modified with (3-aminopropyl)triethoxysilane, four procedures based on streptavidin–biotin system are compared with Atomic Force Microscopy, Angle-Resolved X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry. The first approach involves: adsorption of biotinylated Bovine Serum Albumin, blocking free surface sites with BSA, binding of streptavidin and biotinylated oligonucleotide (b-oligo). Final steps are exchanged in the second procedure with immobilization of preformed streptavidin–b-oligo conjugate. The third approach consists of streptavidin adsorption, blocking with BSA and b-oligo binding. Finally, streptavidin–b-oligo conjugate is immobilized directly within the fourth method. Surface coverage with biomolecules, determined from ARXPS, accords with average AFM height, and is anti-correlated with the intensity of Si+ ions. Higher biomolecular coverage was achieved during the last steps of the first (2.45(±0.38) mg/m{sup 2}) and second (1.31(±0.22) mg/m{sup 2}) approach, as compared to lower surface density resulting from the third (0.58(±0.20) mg/m{sup 2}) and fourth (0.41(±0.11) mg/m{sup 2}) method. Phosphorus atomic concentration indicates effectiveness of oligonucleotide immobilization. Secondary ions intensities, characteristic for oligonucleotides, streptavidin, BSA, and proteins, allow additional insight into overlayer composition. These measurements verify the ARXPS results and show the superiority of the first two immobilization approaches in terms of streptavidin and oligonucleotide density achieved onto the surface.

  6. Immobilization of oligonucleotide probes on silicon surfaces using biotin–streptavidin system examined with microscopic and spectroscopic techniques

    International Nuclear Information System (INIS)

    Awsiuk, K.; Rysz, J.; Petrou, P.; Budkowski, A.; Bernasik, A.; Kakabakos, S.; Marzec, M.M.; Raptis, I.

    2014-01-01

    To immobilize effectively oligonucleotide probes on SiO 2 modified with (3-aminopropyl)triethoxysilane, four procedures based on streptavidin–biotin system are compared with Atomic Force Microscopy, Angle-Resolved X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry. The first approach involves: adsorption of biotinylated Bovine Serum Albumin, blocking free surface sites with BSA, binding of streptavidin and biotinylated oligonucleotide (b-oligo). Final steps are exchanged in the second procedure with immobilization of preformed streptavidin–b-oligo conjugate. The third approach consists of streptavidin adsorption, blocking with BSA and b-oligo binding. Finally, streptavidin–b-oligo conjugate is immobilized directly within the fourth method. Surface coverage with biomolecules, determined from ARXPS, accords with average AFM height, and is anti-correlated with the intensity of Si+ ions. Higher biomolecular coverage was achieved during the last steps of the first (2.45(±0.38) mg/m 2 ) and second (1.31(±0.22) mg/m 2 ) approach, as compared to lower surface density resulting from the third (0.58(±0.20) mg/m 2 ) and fourth (0.41(±0.11) mg/m 2 ) method. Phosphorus atomic concentration indicates effectiveness of oligonucleotide immobilization. Secondary ions intensities, characteristic for oligonucleotides, streptavidin, BSA, and proteins, allow additional insight into overlayer composition. These measurements verify the ARXPS results and show the superiority of the first two immobilization approaches in terms of streptavidin and oligonucleotide density achieved onto the surface.

  7. Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils

    Science.gov (United States)

    Hanvey, S.; Glegg, M.; Foster, J.

    2009-09-01

    This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

  8. Binding and orientation of fibronectin on polystyrene surfaces using immobilized bacterial adhesin-related peptides.

    Science.gov (United States)

    Klueh, U; Bryers, J D; Kreutzer, D L

    2003-10-01

    Fibronectin (FN) is known to bind to bacteria via high affinity receptors on bacterial surfaces known as adhesins. The binding of bacteria to FN is thought to have a key role in foreign device associated infections. For example, previous studies have indicated that Staphylococcus aureus adhesins bind to the 29 kDa NH(3) terminus end of FN, and thereby promote bacteria adherence to surfaces. Recently, the peptide sequences within the S. aureus adhesin molecule that are responsible for FN binding have been identified. Based on these observations, we hypothesize that functional FN can be bound and specifically oriented on polystyrene surfaces using bacterial adhesin-related (BRP-A) peptide. We further hypothesize that monoclonal antibodies that react with specific epitopes on the FN can be used to quantify both FN binding and orientation on these surfaces. Based on this hypothesis, we initiated a systematic investigation of the binding and orientation of FN on polystyrene surfaces using BRP-A peptide. To test this hypothesis, the binding and orientation of the FN to immobilized BRP-A was quantified using (125)I-FN, and monoclonal antibodies. (125)I-FN was used to quantitate FN binding to peptide-coated polystyrene surfaces. The orientation of bound FN was demonstrated by the use of monoclonal antibodies, which are reactive with the amine (N) or carboxyl (C) termini of the FN. The results of our studies demonstrated that when the BRP-A peptide was used to bind FN to surfaces that: 1. functional FN was bound to the peptide; 2. anti-C terminus antibodies bound to the peptide FN; and 3. only limited binding of anti-N terminus antibodies to peptide-bound FN occurred. We believe that the data that indicate an enhanced binding of anti-C antibodies reactive to anti-N antibodies are a result of the FN binding in an oriented manner with the N termini of FN bound tightly to the BRP-A on the polystyrene surface. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 36

  9. Surface modification of Fe_2O_3/Fe_3O_4 nanocomposites for use in immobilization of glucose oxidase

    International Nuclear Information System (INIS)

    Albuquerque, I.L.T.; Santos, P.T.A.; Costa, A.C.F.M.; Oliveira, L.S.C.

    2017-01-01

    The increase in the number of people with diabetes in recent years and the high cost-benefit ratio of the existing biosensor technology have increased the interest for the development of glucose detection biosensor based on immobilization of glucose-oxidase (GOD) mainly using magnetic nanoparticles. In this context, nanocomposites of Fe_2O_3/Fe_3O_4 were prepared by combustion reaction and their surface was functionalized with 3-aminopropyltriethoxysilane via silanization reaction and with chitosan via functionalization to obtain a hybrid material that was evaluated as possible GOD immobilizer. The samples were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, transmission electron microscopy, magnetic properties and in vitro cytotoxicity. The results revealed that it was possible to obtain the ferrimagnetic composite, the surface modification reduced the saturation magnetization, but maintained the ferrimagnetic characteristics, and all samples were considered non-toxic. For preliminary testing of the GOD immobilization it was revealed that the nanocomposite modified with silane and chitosan showed the better result, about 2.7 mg of immobilized GOD for 100 mg of nanocomposite, which makes this material a potential alternative to manufacture GOD biosensors. (author)

  10. Pore Structure and Fluoride Ion Adsorption Characteristics of Zr (IV) Surface-Immobilized Resin Prepared Using Polystyrene as a Porogen

    Science.gov (United States)

    Mizuki, Hidenobu; Ito, Yudai; Harada, Hisashi; Uezu, Kazuya

    Zr(IV) surface-immobilized resins for removal of fluoride ion were prepared by surface template polymerization using polystyrene as a porogen. At polymerization, polystyrene was added in order to increase mesopores (2-50 nm) and macropore (>50 nm) with large macropores (around 300 nm) formed with internal aqueous phase of W⁄O emulsion. The pore structure of Zr(IV) surface-immobilized resins was evaluated by measuring specific surface area, pore volume, and pore size distribution with volumetric adsorption measurement instrument and mercury porosimeter. The adsorption isotherms were well fitted by Langmuir equation. The removal of fluoride was also carried out with column method. Zr(IV) surface-immobilized resins, using 10 g⁄L polystyrene in toluene at polymerization, possessed higher volume of not only mesopores and macropores but also large macropores. Furethermore, by adding the polystyrene with smaller molecular size, the pore volume of mesopores, macropores and large macropores was significantly increased, and the fluoride ion adsorption capacity and the column utilization also increased.

  11. Energy transfer between surface-immobilized light-harvesting chlorophyll a/b complex (LHCII) studied by surface plasmon field-enhanced fluorescence spectroscopy (SPFS).

    Science.gov (United States)

    Lauterbach, Rolf; Liu, Jing; Knoll, Wolfgang; Paulsen, Harald

    2010-11-16

    The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCII potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCII to be immobilized on a solid surface. In a previous study we showed the immobilization of recombinant LHCII on functionalized gold surfaces via a 6-histidine tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Förster energy transfer between immobilized LHCII on a functionalized surface have been analyzed by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCII.

  12. Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide

    Energy Technology Data Exchange (ETDEWEB)

    Buckholtz, Gavin A.; Reger, Nina A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Anderton, William D.; Schimoler, Patrick J. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Roudebush, Shana L.; Meng, Wilson S. [Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282 (United States); Miller, Mark C. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219 (United States)

    2016-08-01

    A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0–5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (> 180%) and proliferation (> 140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (> 99.6% after 24 h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

  13. Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide

    International Nuclear Information System (INIS)

    Buckholtz, Gavin A.; Reger, Nina A.; Anderton, William D.; Schimoler, Patrick J.; Roudebush, Shana L.; Meng, Wilson S.; Miller, Mark C.; Gawalt, Ellen S.

    2016-01-01

    A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0–5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (> 180%) and proliferation (> 140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (> 99.6% after 24 h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

  14. Interaction force measurement between E. coli cells and nanoparticles immobilized surfaces by using AFM.

    Science.gov (United States)

    Zhang, Wen; Stack, Andrew G; Chen, Yongsheng

    2011-02-01

    To better understand environmental behaviors of nanoparticles (NPs), we used the atomic force microscopy (AFM) to measure interaction forces between E. coli cells and NPs immobilized on surfaces in an aqueous environment. The results showed that adhesion force strength was significantly influenced by particle size for both hematite (α-Fe(2)O(3)) and corundum (α-Al(2)O(3)) NPs whereas the effect on the repulsive force was not observed. The adhesion force decreased from 6.3±0.7nN to 0.8±0.4nN as hematite NPs increased from 26nm to 98nm in diameter. Corundum NPs exhibited a similar dependence of adhesion force on particle size. The Johnson-Kendall-Roberts (JKR) model was employed to estimate the contact area between E. coli cells and NPs, and based on the JKR model a new model that considers local effective contact area was developed. The prediction of the new model matched the size dependence of adhesion force in experimental results. Size effects on adhesion forces may originate from the difference in local effective contact areas as supported by our model. These findings provide fundamental information for interpreting the environmental behaviors and biological interactions of NPs, which barely have been addressed. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Direct Profiling the Post-Translational Modification Codes of a Single Protein Immobilized on a Surface Using Cu-free Click Chemistry.

    Science.gov (United States)

    Kim, Kyung Lock; Park, Kyeng Min; Murray, James; Kim, Kimoon; Ryu, Sung Ho

    2018-05-23

    Combinatorial post-translational modifications (PTMs), which can serve as dynamic "molecular barcodes", have been proposed to regulate distinct protein functions. However, studies of combinatorial PTMs on single protein molecules have been hindered by a lack of suitable analytical methods. Here, we describe erasable single-molecule blotting (eSiMBlot) for combinatorial PTM profiling. This assay is performed in a highly multiplexed manner and leverages the benefits of covalent protein immobilization, cyclic probing with different antibodies, and single molecule fluorescence imaging. Especially, facile and efficient covalent immobilization on a surface using Cu-free click chemistry permits multiple rounds (>10) of antibody erasing/reprobing without loss of antigenicity. Moreover, cumulative detection of coregistered multiple data sets for immobilized single-epitope molecules, such as HA peptide, can be used to increase the antibody detection rate. Finally, eSiMBlot enables direct visualization and quantitative profiling of combinatorial PTM codes at the single-molecule level, as we demonstrate by revealing the novel phospho-codes of ligand-induced epidermal growth factor receptor. Thus, eSiMBlot provides an unprecedentedly simple, rapid, and versatile platform for analyzing the vast number of combinatorial PTMs in biological pathways.

  16. Study of Immobilization Procedure on Silver Nanolayers and Detection of Estrone with Diverged Beam Surface Plasmon Resonance (SPR Imaging

    Directory of Open Access Journals (Sweden)

    Ibrahim Abdulhalim

    2013-03-01

    Full Text Available An immobilization protocol was developed to attach receptors on smooth silver thin films. Dense and packed 11-mercaptoundecanoic acid (11-MUA was used to avoid uncontrolled sulfidization and harmful oxidation of silver nanolayers. N,N'-dicyclohexylcarbodiimide (DCC and N-hydroxysuccinimide (NHS were added to make the silver surfaces reactive. A comparative study was carried out with different immersion times of silver samples in 11-MUA solutions with different concentrations to find the optimum conditions for immobilization. The signals, during each step of the protocol, were analyzed with a refractometer based on the surface plasmon resonance (SPR effect and luminescence techniques. Molecular interactions at the surfaces between the probe and target at the surface nanolayer shift the SPR signal, thus indicating the presence of the substance. To demonstrate specific biosensing, rabbit anti-estrone polyclonal immunoglobulin G (IgG antibody was immobilized through a linker on 47 nm silver layer deposited on SF11 glass. At the final stage, the representative endocrine disruptor—estrone—was attached and detected in deionized water with a diverging beam SPR imaging sensor.

  17. Surface immobilized antibody orientation determined using ToF-SIMS and multivariate analysis.

    Science.gov (United States)

    Welch, Nicholas G; Madiona, Robert M T; Payten, Thomas B; Easton, Christopher D; Pontes-Braz, Luisa; Brack, Narelle; Scoble, Judith A; Muir, Benjamin W; Pigram, Paul J

    2017-06-01

    characterization of surface immobilized and oriented antibodies, are under-utilized in current practice. Selection of a small number of mass fragments for analysis, typically pertaining to amino acids, is commonplace in literature, leaving the majority of the information-rich spectra unanalyzed. The novelty of this work is the utilization of a comprehensive, unbiased mass fragment list and the employment of principal component analysis (PCA) and artificial neural network (ANN) models in a unique methodology to prove antibody orientation. This methodology is of significant and broad interest to the scientific community as it is applicable to a range of substrates and allows for direct, label-free characterization of surface bound proteins. Copyright © 2017 Acta Materialia Inc. All rights reserved.

  18. Immobilization of gold nanoparticles on cell culture surfaces for safe and enhanced gold nanoparticle-mediated laser transfection

    Science.gov (United States)

    Kalies, Stefan; Heinemann, Dag; Schomaker, Markus; Gentemann, Lara; Meyer, Heiko; Ripken, Tammo

    2014-01-01

    Abstract. In comparison to standard transfection methods, gold nanoparticle-mediated laser transfection has proven to be a versatile alternative. This is based on its minor influence on cell viability and its high efficiency, especially for the delivery of small molecules like small interfering RNA. However, in order to transfer it to routine usage, a safety aspect is of major concern: The avoidance of nanoparticle uptake by the cells is desired. The immobilization of the gold nanoparticles on cell culture surfaces can address this issue. In this study, we achieved this by silanization of the appropriate surfaces and the binding of gold nanoparticles to them. Comparable perforation efficiencies to the previous approaches of gold nanoparticle-mediated laser transfection with free gold nanoparticles are demonstrated. The uptake of the immobilized particles by the cells is unlikely. Consequently, these investigations offer the possibility of bringing gold nanoparticle-mediated laser transfection closer to routine usage. PMID:25069006

  19. Self-assembled monolayers of 1-alkenes on oxidized platinum surfaces as platforms for immobilized enzymes for biosensing

    International Nuclear Information System (INIS)

    Alonso, Jose Maria; Bielen, Abraham A.M.; Olthuis, Wouter; Kengen, Servé W.M.; Zuilhof, Han; Franssen, Maurice C.R.

    2016-01-01

    Highlights: • Three different oxidases are covalently attached to alkene based SAMs on PtOx. • Attached enzymes remain active and their activity is assessed by chronoamperometry. • Functionalized PtOx allows electron mediator free chronoamperometry measurements. • The thus formed enzyme electrodes are useful as biosensors for glucose and lactate. • Immobilization of human HAOX foresees in vivo lactate monitoring in humans. - Abstract: Alkene-based self-assembled monolayers grafted on oxidized Pt surfaces were used as a scaffold to covalently immobilize oxidase enzymes, with the aim to develop an amperometric biosensor platform. NH_2-terminated organic layers were functionalized with either aldehyde (CHO) or N-hydroxysuccinimide (NHS) ester-derived groups, to provide anchoring points for enzyme immobilization. The functionalized Pt surfaces were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (CA), infrared reflection absorption spectroscopy (IRRAS) and atomic force microscopy (AFM). Glucose oxidase (GOX) was covalently attached to the functionalized Pt electrodes, either with or without additional glutaraldehyde crosslinking. The responses of the acquired sensors to glucose concentrations ranging from 0.5 to 100 mM were monitored by chronoamperometry. Furthermore, lactate oxidase (LOX) and human hydroxyacid oxidase (HAOX) were successfully immobilized onto the PtOx surface platform. The performance of the resulting lactate sensors was investigated for lactate concentrations ranging from 0.05 to 20 mM. The successful attachment of active enzymes (GOX, LOX and HAOX) on Pt electrodes demonstrates that covalently functionalized PtOx surfaces provide a universal platform for the development of oxidase enzyme-based sensors.

  20. Self-assembled monolayers of 1-alkenes on oxidized platinum surfaces as platforms for immobilized enzymes for biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Jose Maria; Bielen, Abraham A.M. [Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB, Wageningen (Netherlands); Olthuis, Wouter [BIOS Lab on a Chip Group, MESA+ and MIRA Institutes, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Kengen, Servé W.M. [Laboratory of Microbiology, Wageningen University, 6703HB Wageningen (Netherlands); Zuilhof, Han, E-mail: han.zuilhof@wur.nl [Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB, Wageningen (Netherlands); Department of Chemical and Materials Engineering, King Abdulaziz University, Jeddah 22254 (Saudi Arabia); Franssen, Maurice C.R., E-mail: maurice.franssen@wur.nl [Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB, Wageningen (Netherlands)

    2016-10-15

    Highlights: • Three different oxidases are covalently attached to alkene based SAMs on PtOx. • Attached enzymes remain active and their activity is assessed by chronoamperometry. • Functionalized PtOx allows electron mediator free chronoamperometry measurements. • The thus formed enzyme electrodes are useful as biosensors for glucose and lactate. • Immobilization of human HAOX foresees in vivo lactate monitoring in humans. - Abstract: Alkene-based self-assembled monolayers grafted on oxidized Pt surfaces were used as a scaffold to covalently immobilize oxidase enzymes, with the aim to develop an amperometric biosensor platform. NH{sub 2}-terminated organic layers were functionalized with either aldehyde (CHO) or N-hydroxysuccinimide (NHS) ester-derived groups, to provide anchoring points for enzyme immobilization. The functionalized Pt surfaces were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (CA), infrared reflection absorption spectroscopy (IRRAS) and atomic force microscopy (AFM). Glucose oxidase (GOX) was covalently attached to the functionalized Pt electrodes, either with or without additional glutaraldehyde crosslinking. The responses of the acquired sensors to glucose concentrations ranging from 0.5 to 100 mM were monitored by chronoamperometry. Furthermore, lactate oxidase (LOX) and human hydroxyacid oxidase (HAOX) were successfully immobilized onto the PtOx surface platform. The performance of the resulting lactate sensors was investigated for lactate concentrations ranging from 0.05 to 20 mM. The successful attachment of active enzymes (GOX, LOX and HAOX) on Pt electrodes demonstrates that covalently functionalized PtOx surfaces provide a universal platform for the development of oxidase enzyme-based sensors.

  1. Surface modification of polyacrylonitrile fiber for immobilization of antibodies and detection of analyte

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Swati, E-mail: swatijain.iitd@gmail.com [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India); Chattopadhyay, Sruti, E-mail: srutic@hotmail.com [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India); Jackeray, Richa, E-mail: richajackeray.iitd@gmail.com [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India); Singh, Harpal, E-mail: harpal2000@yahoo.com [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India)

    2009-11-10

    Pendent nitrile groups of multifilamentous polyacrylonitrile (PAN) fibers were reduced to amino groups using lithium aluminum hydride for different time of reduction and amine content was estimated by performing acid-base titrations. Attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) were used for the characterization of the generated amino groups and thermal properties of the reduced fibers, respectively. The surface morphology of the fibers after reduction and immobilization was characterized using Scanning Electron Microscope (SEM). The newly formed amino groups of the fibers were activated by using glutaraldehyde for the covalent linking of Goat anti-Rabbit IgG-HRP (GAR-HRP) antibody enzyme conjugate. Modified PAN fibers were evaluated as a matrix for sandwich ELISA by using Goat anti-Rabbit antibody (GAR-IgG), Rabbit anti-Goat (RAG-IgG) as analyte and enzyme conjugate GAR-HRP. The fibers reduced for 24 h were able to detect the analyte RAG-IgG at a concentration as low as 3.75 ng mL{sup -1} with 12% skimmed milk as blocking reagent for the optimized concentration of primary antibody GAR-IgG 3 {mu}g mL{sup -1} and peroxidase conjugate GAR-HRP dilution of 8000 fold. The sensitivity, specificity and reproducibility of the developed immunoassay was further established with antibodies present in human blood using Rabbit anti-Human (RAH-IgG) antibody and the corresponding HRP enzyme conjugate. As low as 0.1 {mu}L of human blood was sufficient to perform the assay with the modified fibers.

  2. IMMOBILIZATION OF MICROALGAE ON THE SURFACE OF NEW CROSS-LINKED POLYETHYLENIMINE-BASED SORBENTS.

    Science.gov (United States)

    Vasilieva, Svetlana; Shibzukhova, Karina; Morozov, Alexey; Solovchenko, Alexei; Bessonov, Ivan; Kopitsyna, Maria; Lukyanov, Alexander; Chekanov, Konstantin; Lobakova, Elena

    2018-04-11

    We report on the use of the polyethylenimine-based (PEI) sorbents for immobilization and harvesting of microalgae (MA) cells. Specific materials assessed were porous solid polymers from highly-branched PEI synthesized by cross-linking with epichlorohydrin (ECH) or diethylene glycol diglycidyl ether (DGDE). We estimated the effect of PEI/cross-linker ratio on the MA attachment and biocompatibility of the sorbents with the MA cells. A decrease in the cross-linker percentage resulted in the enhancement of the immobilization efficiency but impaired the cell viability as was manifested by inhibition of the photosynthetic activity of the MA cells. The rate of Chlorella vulgaris cell attachment to the sorbents with ECH was faster as compared to that of the PEI-DGDE-based polymers. The cells immobilized on the PEI-ECH sorbents showed a more profound decline in their viability (assessed via photosynthetic activity). The sorbents with 60% of DGDE were characterized by high immobilization efficiency. These sorbents supported a prolonged cultivation of the immobilized MA without impairing their viability and metabolic activity. We conclude that the sorbents with a lower percentage of DGDE (<30%) and sorbents with ECH are suitable for harvesting of the MA cells intended for immediate downstream processing, potentially without the cell desorption. To the best of our knowledge, this is the first report on successful application of PEI-based sorbents in microalgal biotechnology. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. The effect of the shape of single, sub-ms voltage pulses on the rates of surface immobilization and hybridization of DNA

    International Nuclear Information System (INIS)

    Cabeca, R; Rodrigues, M; Chu, V; Conde, J P; Prazeres, D M F

    2009-01-01

    Electric fields generated by single square and sinusoidal voltage pulses with amplitudes below 2 V were used to assist the covalent immobilization of single-stranded, thiolated DNA probes, onto a chemically functionalized SiO 2 surface and to assist the specific hybridization of single-stranded DNA targets with immobilized complementary probes. The single-stranded immobilized DNA probes were either covalently immobilized (chemisorption) or electrostatically adsorbed (physisorption) to a chemically functionalized surface. Comparing the speed of electric field assisted immobilization and hybridization with the corresponding control reactions (without electric field), an increase of several orders of magnitude is observed, with the reaction timescaled down from 1 to 2 h to a range between 100 ns and 1 ms. The influence of the shape of the voltage pulse (square versus sinusoidal) and its duration were studied for both immobilization and hybridization reactions. The results show that pulsed electric fields are a useful tool to achieve temporal and spatial control of surface immobilization and hybridization reactions of DNA.

  4. Improved functional immobilization of llama single-domain antibody fragments to polystyrene surfaces using small peptides

    NARCIS (Netherlands)

    Harmsen, M.M.; Fijten, H.P.D.

    2012-01-01

    We studied the effect of different fusion domains on the functional immobilization of three llama single-domain antibody fragments (VHHs) after passive adsorption to polystyrene in enzyme-linked immunosorbent assays (ELISA). Three VHHs produced without any fusion domain were efficiently adsorbed to

  5. The immobilization of filamentous fungi by cellular adherence and surface film growth on radiopolymerized hydrogels

    International Nuclear Information System (INIS)

    Petre, M.; Zarnea, G.; Adrian, P.; Gheorghiu, E.; Gheordunescu, V.

    1998-01-01

    The continuous biodegradation processes of cellulose wastes, from wine-producing industry and canned food processing were performed using immobilized fungal cells on complex polyhydrogels such as: collagen-polyacrylamide (CPAA), elastin-polyacrylamide (EPAA), gelatin-polyacrylamide (GPAA) and poly-hydroxy-ethyl-methyl-methacrylate (PHEMA) which were prepared by experimental radiopolymerization methods using a 60 Co radioactive source. The experiments were performed using cellulolytic micro- and macrofungal species and the immobilization methods were applied in connection with morphogenetic characteristics of each one of these species that were used as inoculum. A flow-cascade bioreactor was achieved as a research laboratory tool in order to control the cellulose waste biodegradation in continuous processes using immobilized fungal cells on complex polyhydrogels. In this way the continuous control was possible for fungal metabolic activity during the cellulose biodegradation processes by microscopical hyphal growth measurements inside the polyhydrogels and, also, by mycelial protein content analysis. The tested fungal species were Pleurotus ostreatus and Pleurotus florida from macromycetes and Trichoderma viride from micromycetes. There were noticed significant differences in biodegradation rate of cellulose wastes between 'in vitro' immobilized fungal cultures and free fungal cells cultures used as control samples to be compared with cellulose biodegradation processes in natural conditions of polluted ecosystems. The fungal growth displayed by soluble mycelial protein were compared with cellulose biodegradation rates which were expressed by cellulose weight loss in the culture medium. (authors)

  6. Immobilization of ionophore and surface characterization studies of the titanium(III) ion in a PVC-membrane sensor.

    Science.gov (United States)

    Rezayi, Majid; Heng, Lee Yook; Kassim, Anuar; Ahmadzadeh, Saeid; Abdollahi, Yadollah; Jahangirian, Hossein

    2012-01-01

    Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride) (PVC) matrices, and these were examined to determine Ti(III) selectivity. To predict the selectivity of Ti(III), a PVC membrane was used to investigate the binding of Ti(III) to c-methylcalix[4]resorcinarene (CMCR). The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III) at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl) borate (NaTFPB) as a lipophilic ionic additive, and dioctylphthalate (DOP) as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs). The strengths of the ion-ionophore (CMCR-Ti(OH)(OH(2))(5) (2+)) interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and and X-ray diffraction (XRD).

  7. Surface Immobilization of Human Arginase-1 with an Engineered Ice Nucleation Protein Display System in E. coli.

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    Full Text Available Ice nucleation protein (INP is frequently used as a surface anchor for protein display in gram-negative bacteria. Here, MalE and TorA signal peptides, and three charged polypeptides, 6×Lys, 6×Glu and 6×Asp, were anchored to the N-terminus of truncated INP (InaK-N to improve its surface display efficiency for human Arginase1 (ARG1. Our results indicated that the TorA signal peptide increased the surface translocation of non-protein fused InaK-N and human ARG1 fused InaK-N (InaK-N/ARG1 by 80.7% and 122.4%, respectively. Comparably, the MalE signal peptide decreased the display efficiencies of both the non-protein fused InaK-N and InaK-N/ARG1. Our results also suggested that the 6×Lys polypeptide significantly increased the surface display efficiency of K6-InaK-N/ARG1 by almost 2-fold, while also practically abolishing the surface translocation of non-protein fused InaK-N, indicating the interesting roles of charged polypeptides in bacteria surface display systems. Cell surface-immobilized K6-InaK-N/ARG1 presented an arginase activity of 10.7 U/OD600 under the optimized conditions of 40°C, pH 10.0 and 1 mM Mn2+, which could convert more than 95% of L-Arginine (L-Arg to L-Ornithine (L-Orn in 16 hours. The engineered InaK-Ns expanded the INP surface display system, which aided in the surface immobilization of human ARG1 in E. coli cells.

  8. Guest-Host Complex Formed between Ascorbic Acid and β-Cyclodextrin Immobilized on the Surface of an Electrode

    Directory of Open Access Journals (Sweden)

    María Teresa Ramírez-Silva

    2014-05-01

    Full Text Available This work deals with the formation of supramolecular complexes between ascorbic acid (AA, the guest, and β-cyclodextrin (β-CD, the host, that was first potentiodynamically immobilized on the surface of a carbon paste electrode (CPE throughout the formation of a β-CD-based conducting polymer (poly-β-CD. With the bare CPE and the β-CD-modified CPE, an electrochemical study was performed to understand the effect of such surface modification on the electrochemical response of the AA. From this study it was shown that on the modified-CPE, the AA was surface-immobilized through formation of an inclusion complex with β-CD, which provoked the adsorption of AA in such a way that this stage became the limiting step for the electrochemical oxidation of AA. Moreover, from the analysis of the experimental voltammetric plots recorded during AA oxidation on the CPE/poly-β-CD electrode surfaces, the Gibbs’ standard free energy of the inclusion complex formed by the oxidation product of AA and β-CD has been determined for the first time, ∆G0inclus = −36.4 kJ/mol.

  9. Cobalt(II phthalocyanine bonded to 3-n-propylimidazole immobilized on silica gel surface: preparation and electrochemical properties

    Directory of Open Access Journals (Sweden)

    Fujiwara Sergio T.

    1999-01-01

    Full Text Available Co-Phthalocyanine complex was immobilized on 3-n-propylimidazole groups grafted on a porous SiO2 surface (specific surface area S BET = 500 m² g-1 and efficiently electrocatalyzed the oxalic acid oxidation on a carbon paste electrode surface made of this material. Intermolecular interactions of the complex species which can normally interfere in the redox process practically are not observed in the present case because of a low average surface density, delta = 4.7 x 10-13 mol cm-2 (delta = Nf/S BET, where Nf is the amount of adsorbed Co-phtalocyanine per gram of modified silica gel of the complex species material prepared. The linear response of the electrode to oxalic acid concentration, between 6.5 x 10-4 and 3.2 x 10-3 mol L-1, associated with its high chemical stability makes the covalently immobilized Co-phtalocyanine complex material very attractive in preparing a new class of chemical sensors.

  10. Ultra-small rhenium nanoparticles immobilized on DNA scaffolds: An excellent material for surface enhanced Raman scattering and catalysis studies.

    Science.gov (United States)

    Anantharaj, S; Sakthikumar, K; Elangovan, Ayyapan; Ravi, G; Karthik, T; Kundu, Subrata

    2016-12-01

    Highly Sensitive and ultra-small Rhenium (Re) metal nanoparticles (NPs) were successfully stabilized in water by the staging and fencing action of the versatile biomolecule DNA that resulted in two distinct aggregated chain-like morphologies with average grain sizes of 1.1±0.1nm and 0.7±0.1nm for the very first time within a minute of reaction time. Re NPs are formed by the borohydride reduction of ammonium perrhenate (NH4ReO4) in the presence of DNA at room temperature (RT) under stirring. The morphologies were controlled by carefully monitoring the molar ratio of NH4ReO4 and DNA. The synthesized material was employed in two potential applications: as a substrate for surface enhanced Raman scattering (SERS) studies and as a catalyst for the reduction of aromatic nitro compounds. SERS study was carried out by taking methylene blue (MB) as the probe and the highest SERS enhancement factor (EF) of 2.07×10(7) was found for the aggregated chain-like having average grain size of 0.7±0.1nm. Catalytic reduction of 4-nitro phenol (4-NP), 2-nitro phenol (2-NP) and 4-nitroaniline (4-NA) with a rate constant value of 6×10(-2)min(-1), 33.83×10(-2)min(-1) and 37.4×10(-2)min(-1) have testified the excellent catalytic performance of our Re NPs immobilized on DNA. The overall study have revealed the capability of DNA in stabilizing the highly reactive Re metal at nanoscale and made them applicable in practice. The present route can also be extended to prepare one dimensional (1-D), self-assembled NPs of other reactive metals, mixed metals or even metal oxides for specific applications in water based solutions. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Supramolecular protein immobilization on lipid bilayers

    NARCIS (Netherlands)

    Bosmans, R.P.G.; Hendriksen, W.E.; Verheijden, Mark Lloyd; Eelkema, R.; Jonkheijm, Pascal; van Esch, J.H.; Brunsveld, Luc

    2015-01-01

    Protein immobilization on surfaces, and on lipid bilayers specifically, has great potential in biomolecular and biotechnological research. Of current special interest is the immobilization of proteins using supramolecular noncovalent interactions. This allows for a reversible immobilization and

  12. Immobilization, hybridization, and oxidation of synthetic DNA on gold surface: Electron transfer investigated by electrochemistry and scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McEwen, Gerald D.; Chen Fan [Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322-4105 (United States); Zhou Anhong, E-mail: Anhong.Zhou@usu.edu [Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322-4105 (United States)

    2009-06-08

    Fundamental understanding of interfacial electron transfer (ET) among electrolyte/DNA/solid-surface will facilitate the design for electrical detection of DNA molecules. In this report, the electron transfer characteristics of synthetic DNA (sequence from pathogenic Cryptosporidium parvum) self-assembled on a gold surface was electrochemically studied. The effects of immobilization order on the interface ET related parameters such as diffusion coefficient (D{sub 0}), surface coverage ({theta}{sub R}), and monolayer thickness (d{sub i}) were determined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). DNA surface density ({Gamma}{sub DNA}) was determined by the integration of the charge of the electro-oxidation current peaks during the initial cyclic voltammetry scans. It was found that the DNA surface densities at different modifications followed the order: {Gamma}{sub DNA} (dsS-DNA/Au) > {Gamma}{sub DNA} (MCH/dsS-DNA/Au) > {Gamma}{sub DNA} (dsS-DNA/MCH/Au). It was also revealed that the electro-oxidation of the DNA modified gold surface would involve the oxidation of nucleotides (guanine and adenine) with a 5.51 electron transfer mechanism and the oxidative desorption of DNA and MCH molecules by a 3 electron transfer mechanism. STM topography and current image analysis indicated that the surface conductivity after each surface modification followed the order: dsS-DNA/Au < MCH/dsS-DNA/Au < oxidized MCH/dsS-DNA/Au < Hoechst/oxidized MCH/dsS-DNA/Au. The results from this study suggested a combination of variations in immobilization order may provide an alternative approach for the optimization of DNA hybridization and the further development for electrical detection of DNA.

  13. Supply and cost factors for metals in the Canadian nuclear fuel waste immobilization program

    International Nuclear Information System (INIS)

    McConnell, D.B.

    1982-11-01

    Estimates have been made of the demand for immobilization containers to accommodate the irradiated fuel bundles arising from Canadian nuclear generating stations to the year 2020. The resulting estimates for container shells and container-filling alloys were compared to estimates for Canadian and Western World production of the candiate metals. The results indicate that, among the container shell metals, supply difficulties might arise only for Grade 7 titanium. Among the filling metals, only lead-antimony alloy might present supply problems. Current cost figures for plate made of each shell metal, and bulk quantities of filling metals, were compared. Materials costs would be least for a supported shell of stainless steel, followed by copper, titanium alloys Grades 2, 12 and 7, and Inconel 625. Aluminum-silicon is the lowest-cost filling matrix, followed by zinc, lead, and lead-antimony. Container durability, vault conditions, groundwater composition and other factors may play an overriding role in the final selection of materials for container construction

  14. Immobilization of cross linked Col-I–OPN bone matrix protein on aminolysed PCL surfaces enhances initial biocompatibility of human adipogenic mesenchymal stem cells (hADMSC)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Hee; Jyoti, Md. Anirban; Song, Ho-Yeon, E-mail: songmic@sch.ac.kr

    2014-06-01

    In bone tissue engineering surface modification is considered as one of the important ways of fabricating successful biocompatible material. Addition of biologically active functionality on the surfaces has been tried for improving the overall biocompatibility of the system. In this study poly-ε-caprolactone film surfaces have been modified through aminolysis and immobilization process. Collagen type I (COL-I) and osteopontin (OPN), which play an important role in osteogenesis, was immobilized onto PCL films followed by aminolysis treatment using 1,6-hexanediamine. Characterization of animolysed and immobilized surfaces were done by a number techniques using scanning electron microscopy (SEM), FT-IR, XPS, ninhydrin staining, SDS-PAGE and confocal microscopy and compared between the modified and un-modified surfaces. Results of the successive experiments showed that aminolysis treatment was homogeneously achieved which helped to entrap or immobilize Col-I–OPN proteins on surfaces of PCL film. In vitro studies with human adipogenic mesenchymal stem cells (hADMSC) also confirmed the attachment and proliferation of cells was better in modified PCL surfaces than the unmodified surfaces. SEM, confocal microscopy and MTT assay showed a significant increase in cell spreading, attachment and proliferations on the biofunctionalized surfaces compared to the unmodified PCL surfaces at all-time points indicating the success of surface biofunctionalization.

  15. Size matters: influence of the size of nanoparticles on their interactions with ligands immobilized on the solid surface.

    Science.gov (United States)

    Piletska, Elena V; Piletsky, Sergey A

    2010-03-16

    The correlation between the size of biotinylated nanoparticles and their affinity in relation to interactions with the solid surface was investigated. The silica particles with a diameter of 50-200 nm containing amino groups on the surface were labeled with different quantities of biotin. The affinity properties of biotinylated nanoparticles were studied using a Biacore 3000 instrument equipped with a streptavidin-coated sensor chip (SA chip). It was shown that the increase in the particle size from 50 to 200 nm reduced the affinity (K(D)) of biotin-streptavidin interactions from 1.2 x 10(-12) to 1.2 x 10(-10) M. It was found that the particles with higher concentrations of immobilized biotin on particle surfaces demonstrated stronger binding with streptavidin.

  16. SU-E-T-348: Effect of Treatment Table and Immobilization Devices On Surface Dose When Using a GRID Technique

    Energy Technology Data Exchange (ETDEWEB)

    Gajdos, S; Donaghue, J [Akron General Medical Center, Akron, OH (United States)

    2015-06-15

    Purpose: To determine the increase of surface dose of MLC-designed GRID therapy in the presence of immobilization devices and treatment table. Methods: To create a GRID field, our facility utilizes an MLC consisting of four millimeter wide leaves. The field is designed to have aperture sizes of 0.8 cm X 0.8 cm with inter-aperture distance of 3.2 cm. Gafchromic EBT3 film was placed between the surface of a solid water phantom and the immobilization device. The treatment table was also present within the beam path. The devices consist of carbon fiber exterior shell. A piece of film was also placed at maximal depth for the photon energy of 10 MV. Image files were converted to dose per a calibration curve based on the selected red channel. The surface dose to maximum dose was established by comparing the ratio of seven centrally located aperture regions-of-interest and four adjacent inter-aperture regions-of-interest were measured with the available software tools. Results: With no devices present in beam path, the ratio of surface dose to maximum dose was 11.5% ± 0.3% for aperture region and 7.0% ± 0.1% for inter-aperture region. When devices are present, the ratio of surface dose to maximum dose was 45.2% ± 0.5% and 33.8% ± 1.1%, respectively. Due to the presence of devices, the surface dose increases in aperture region by 3.8 times or in the inter-aperture region by 4.7 times. Conclusion: The purpose of using GRID technique is to deliver a single fractional dose in range of 15–20 Gy to a bulky lesion while also preserving skin tolerance. The increase of surface dose due to devices placed in beam path may increase the chance of skin toxicity in GRID therapy. Care should be used to determine best manageable patient immobilization while considering skin dose especially for posteriorly located lesions.

  17. Assessment on the decolourization of textile dye (Reactive Yellow) using Pseudomonas sp. immobilized on fly ash: Response surface methodology optimization and toxicity evaluation.

    Science.gov (United States)

    Roy, Uttariya; Sengupta, Shubhalakshmi; Banerjee, Priya; Das, Papita; Bhowal, Avijit; Datta, Siddhartha

    2018-06-18

    This study focuses on the investigation of removal of textile dye (Reactive Yellow) by a combined approach of sorption integrated with biodegradation using low cost adsorbent fly ash immobilized with Pseudomonas sp. To ensure immobilization of bacterial species on treated fly ash, fly ash with immobilized bacterial cells was characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and fluorescence microscopy. Comparative batch studies were carried out using Pseudomonas sp, fly ash and immobilized Pseudomonas sp on flyash and were observed that immobilized Pseudomonas sp on flyash acted as better decolourizing agent. The optimized pH, temperature, and immobilized adsorbent dosage for highest percentage of dye removal were observed to be pH 6, 303 K, 1.2 g/L in all the cases. At optimum condition, the highest percentage of dye removal was found to be 88.51%, 92.62% and 98.72% for sorption (flyash), biodegradation (Pseudomonas sp) and integral approach (Pseudomonas sp on flyash) respectively. Optimization of operating parameters of textile dye decolourization was done by response surface methodology (RSM) using Design Expert 7 software. Phytotoxicity evaluation with Cicer arietinum revealed that seeds exposed to untreated dye effluents showed considerably lower growth, inhibited biochemical, and enzyme parameters with compared to those exposed to treated textile effluents. Thus this immobilized inexpensive technique could be used for removal of synthetic dyes present in textile wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Immobilization and Application of Electrospun Nanofiber Scaffold-based Growth Factor in Bone Tissue Engineering.

    Science.gov (United States)

    Chen, Guobao; Lv, Yonggang

    2015-01-01

    Electrospun nanofibers have been extensively used in growth factor delivery and regenerative medicine due to many advantages including large surface area to volume ratio, high porosity, excellent loading capacity, ease of access and cost effectiveness. Their relatively large surface area is helpful for cell adhesion and growth factor loading, while storage and release of growth factor are essential to guide cellular behaviors and tissue formation and organization. In bone tissue engineering, growth factors are expected to transmit signals that stimulate cellular proliferation, migration, differentiation, metabolism, apoptosis and extracellular matrix (ECM) deposition. Bolus administration is not always an effective method for the delivery of growth factors because of their rapid diffusion from the target site and quick deactivation. Therefore, the integration of controlled release strategy within electrospun nanofibers can provide protection for growth factors against in vivo degradation, and can manipulate desired signal at an effective level with extended duration in local microenvironment to support tissue regeneration and repair which normally takes a much longer time. In this review, we provide an overview of growth factor delivery using biomimetic electrospun nanofiber scaffolds in bone tissue engineering. It begins with a brief introduction of different kinds of polymers that were used in electrospinning and their applications in bone tissue engineering. The review further focuses on the nanofiber-based growth factor delivery and summarizes the strategies of growth factors loading on the nanofiber scaffolds for bone tissue engineering applications. The perspectives on future challenges in this area are also pointed out.

  19. Cross-Linked ZnO Nanowalls Immobilized onto Bamboo Surface and Their Use as Recyclable Photocatalysts

    Directory of Open Access Journals (Sweden)

    Chunde Jin

    2014-01-01

    Full Text Available A novel recyclable photocatalyst was fabricated by hydrothermal method to immobilize the cross-linked ZnO nanowalls on the bamboo surface. The resultant samples were characterized by using scanning electron microscopy (SEM, X-ray diffraction (XRD, energy dispersive spectroscopy (EDS, and Fourier transformation infrared (FTIR techniques. FTIR spectra demonstrated that the cross-linked wurtzite ZnO nanowalls and bamboo surface were interconnected with each other by hydrogen bonds. Meanwhile, the cross-linked ZnO nanowalls modified bamboo (CZNB presented a superior photocatalytic ability and could be recycled at least 3 times with a photocatalytic efficiency up to 70%. The current research provides a new opportunity for the development of a portable and recycled biomass-based photocatalysts which can be an efficiently degraded pollutant solution and reused several times.

  20. Pressure Ulcers in Trauma Patients with Preventive Spinal Immobilization : Incidence, characteristics and risk factors

    NARCIS (Netherlands)

    Ham, H.W.

    2016-01-01

    Introduction To protect the (possibly) injured spine, trauma patients are immobilized on a backboard, with an extrication collar, lateral headblocks, and straps. Although pressure ulcers are typically associated with older adults and chronic illness, of all patients in a hospital environment,

  1. Microbial Immobilization of Si, Mn, Fe, and Sr Ions in the Nacreous Layer of Sinohyliopsis schlegeli and Environmental Factors

    Science.gov (United States)

    Tazaki, Kazue; Morii, Issei

    Environmental changes recorded in the shell nacre of Sinohyliopsis schlegeli were observed with elemental factors of characteristic water and nutrition for eight months in a cultivated drainage pond at Kanazawa University, Ishikawa Prefecture, Japan. Tetracycline as an indicator was injected into the shell nacre once every month from May to November in 2007. Water qualities such as the pH, redox potential, electrical conductivity, dissolved oxygen concentration, and water temperature were measured periodically, and the suspended solids in the water were removed by filtration for optical microscopy, X-ray fluorescence analysis, and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) observations. X-ray fluorescence chemical analysis of shell nacre indicated layers with strong tetracycline accumulation corresponding to high concentrations of Si, Mn, Fe, and Sr ions. The redox potential and dissolved oxygen concentration measurements supported the existence of layers in the nacre. The suspended materials in the drainage pond water comprised mainly of Si, Mn, and Fe elements, which were the same elements involved in microbial immobilization in the shell nacre during the summer of 2007. SEM-EDX analyses confirmed that the ions originated from diatoms, Siderocapsa sp. and Gallionella ferruginea in the stomach. There was little microbial immobilization of the ions in winter. The results suggested elemental immobilization in the layered shell nacre and indicated that Sinohyliopsis schlegeli fed on the ions, to grow the nacre during summer. Sinohyliopsis schlegeli with these biogenic oxides might contribute to the scavenging of heavy metals in natural water.

  2. Research of the influencing factors of the immobilized redox mediators accelerating Cr(Ⅵ reduction by Escherichia coli BL21

    Directory of Open Access Journals (Sweden)

    Jiapeng PING

    2017-10-01

    Full Text Available In order to study the influencing factors of non-dissolved redox mediators on Cr (Ⅵ bioreduction, the accelerating effect of non-dissolved redox mediators immobilized by cellulose acetate (CA on the reduction of Cr(Ⅵ by Escherichia coli BL21 is investigated. The results show that the accelerating order is 1-chloroanthraquinone>1,5-dichloroanthraquinone>2-chloroanthraquinone>1,8-dichloroanthraquinone>anthraquinone>1,4,5,8-tetrachloroanthtaquinone; the optimal concentration of 1-chloroanthraquinone pH and initial Cr(Ⅵ concentration are 0.048 mol/L, 7.00 and 30 mg/L, respectively; the removal rate increases with the increasing temperature when it is in the range of 20~60 ℃; after 6 times of recycling experiments, and the Cr(Ⅵ bioreduction rate with the immobilized 1-chloroanthraquinone maintains above 5 times of margin bacterium's. It indicates that non-dissolved redox mediators immobilized by CA can effectively accelerate the reduction rate of Cr(Ⅵ by Escherichia coli BL21, which has favourable application value.

  3. Pinning of the Contact Line during Evaporation on Heterogeneous Surfaces: Slowdown or Temporary Immobilization? Insights from a Nanoscale Study.

    Science.gov (United States)

    Zhang, Jianguo; Müller-Plathe, Florian; Leroy, Frédéric

    2015-07-14

    The question of the effect of surface heterogeneities on the evaporation of liquid droplets from solid surfaces is addressed through nonequilibrium molecular dynamics simulations. The mechanism behind contact line pinning which is still unclear is discussed in detail on the nanoscale. Model systems with the Lennard-Jones interaction potential were employed to study the evaporation of nanometer-sized cylindrical droplets from a flat surface. The heterogeneity of the surface was modeled through alternating stripes of equal width but two chemical types. The first type leads to a contact angle of 67°, and the other leads to a contact angle of 115°. The stripe width was varied between 2 and 20 liquid-particle diameters. On the surface with the narrowest stripes, evaporation occurred at constant contact angle as if the surface was homogeneous, with a value of the contact angle as predicted by the regular Cassie-Baxter equation. When the width was increased, the contact angle oscillated during evaporation between two boundaries whose values depend on the stripe width. The evaporation behavior was thus found to be a direct signature of the typical size of the surface heterogeneity domains. The contact angle both at equilibrium and during evaporation could be predicted from a local Cassie-Baxter equation in which the surface composition within a distance of seven fluid-particle diameters around the contact line was considered, confirming the local nature of the interactions that drive the wetting behavior of droplets. More importantly, we propose a nanoscale explanation of pinning during evaporation. Pinning should be interpreted as a drastic slowdown of the contact line dynamics rather than a complete immobilization of it during a transition between two contact angle boundaries.

  4. Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

    International Nuclear Information System (INIS)

    Navaneetha Pandiyaraj, K.; Ram Kumar, M.C.; Arun Kumar, A.; Padmanabhan, P.V.A.; Deshmukh, R.R.; Bah, M.; Ismat Shah, S.; Su, Pi-Guey; Halleluyah, M.; Halim, A.S.

    2016-01-01

    Graphical abstract: - Highlights: • Developed low cost cold atmospheric plasma reactor for plasma polymerization technique. • Surface of the PP film was modified by grafting of AAc and PEG by CAPP polymerization. • Biomolecules of chitosan, insulin and heparin were immobilized on surface of PEG-AAc grafted PP films. • The surface modified PP films were characterized by various techniques. • The plasma polymerized and immobilized film reveals substantial blood compatibility. - Abstract: Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as O−C=O, C=O, C−N and S−S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was

  5. Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

    Energy Technology Data Exchange (ETDEWEB)

    Navaneetha Pandiyaraj, K., E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T By Pass, Chinniyam Palayam (Post), Coimbatore 641062 (India); Ram Kumar, M.C.; Arun Kumar, A. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T By Pass, Chinniyam Palayam (Post), Coimbatore 641062 (India); Padmanabhan, P.V.A. [PSN College of Engineering and Technology, Tirunelveli 627 152 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Bah, M.; Ismat Shah, S. [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Su, Pi-Guey [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Halleluyah, M.; Halim, A.S. [School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2016-05-01

    Graphical abstract: - Highlights: • Developed low cost cold atmospheric plasma reactor for plasma polymerization technique. • Surface of the PP film was modified by grafting of AAc and PEG by CAPP polymerization. • Biomolecules of chitosan, insulin and heparin were immobilized on surface of PEG-AAc grafted PP films. • The surface modified PP films were characterized by various techniques. • The plasma polymerized and immobilized film reveals substantial blood compatibility. - Abstract: Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as O−C=O, C=O, C−N and S−S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was

  6. Site-Directed Immobilization of Bone Morphogenetic Protein 2 to Solid Surfaces by Click Chemistry.

    Science.gov (United States)

    Siverino, Claudia; Tabisz, Barbara; Lühmann, Tessa; Meinel, Lorenz; Müller, Thomas; Walles, Heike; Nickel, Joachim

    2018-03-29

    Different therapeutic strategies for the treatment of non-healing long bone defects have been intensively investigated. Currently used treatments present several limitations that have led to the use of biomaterials in combination with osteogenic growth factors, such as bone morphogenetic proteins (BMPs). Commonly used absorption or encapsulation methods require supra-physiological amounts of BMP2, typically resulting in a so-called initial burst release effect that provokes several severe adverse side effects. A possible strategy to overcome these problems would be to covalently couple the protein to the scaffold. Moreover, coupling should be performed in a site-specific manner in order to guarantee a reproducible product outcome. Therefore, we created a BMP2 variant, in which an artificial amino acid (propargyl-L-lysine) was introduced into the mature part of the BMP2 protein by codon usage expansion (BMP2-K3Plk). BMP2-K3Plk was coupled to functionalized beads through copper catalyzed azide-alkyne cycloaddition (CuAAC). The biological activity of the coupled BMP2-K3Plk was proven in vitro and the osteogenic activity of the BMP2-K3Plk-functionalized beads was proven in cell based assays. The functionalized beads in contact with C2C12 cells were able to induce alkaline phosphatase (ALP) expression in locally restricted proximity of the bead. Thus, by this technique, functionalized scaffolds can be produced that can trigger cell differentiation towards an osteogenic lineage. Additionally, lower BMP2 doses are sufficient due to the controlled orientation of site-directed coupled BMP2. With this method, BMPs are always exposed to their receptors on the cell surface in the appropriate orientation, which is not the case if the factors are coupled via non-site-directed coupling techniques. The product outcome is highly controllable and, thus, results in materials with homogeneous properties, improving their applicability for the repair of critical size bone defects.

  7. In situ immobilization of proteins and RGD peptide on polyurethane surfaces via poly(ethylene oxide) coupling polymers for human endothelial cell growth.

    Science.gov (United States)

    Wang, Dong-an; Ji, Jian; Sun, Yong-hong; Shen, Jia-cong; Feng, Lin-xian; Elisseeff, Jennifer H

    2002-01-01

    A "CBABC"-type pentablock coupling polymer, mesylMPEO, was designed and synthesized to promote human endothelial cell growth on the surfaces of polyurethane biomaterials. The polymer was composed of a central 4,4'-methylenediphenyl diisocyanate (MDI) coupling unit and poly(ethylene oxide) (PEO) spacer arms with methanesulfonyl (mesyl) end groups pendent on both ends. As the presurface modifying additive (pre-SMA), the mesylMPEO was noncovalently introduced onto the poly(ether urethane) (PEU) surfaces by dip coating, upon which the protein/peptide factors (gelatin, albumin, and arginine-glycine-aspartic acid tripeptide [RGD]) were covalently immobilized in situ by cleavage of the original mesyl end groups. The pre-SMA synthesis and PEU surface modification were characterized using nuclear magnetic resonance spectroscopy ((1)H NMR), attenuated total reflection infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). Human umbilical vein endothelial cells (HUVEC) were harvested manually by collagenase digestion and seeded on the modified PEU surfaces. Cell adhesion ratios (CAR) and cell proliferation ratios (CPR) were measured using flow cytometry, and the individual cell viability (ICV) was determined by MTT assay. The cell morphologies were investigated by optical inverted microscopy (OIM) and scanning electrical microscopy (SEM). The gelatin- and RGD-modified surfaces were HUVEC-compatible and promoted HUVEC growth. The albumin-modified surfaces were compatible but inhibited cell adhesion. The results also indicated that, for HUVEC in vitro cultivation, the cell adhesion stage was of particular importance and had a significant impact on the cell responses to the modified surfaces.

  8. Iron oxidation kinetics and phosphorus immobilization at the groundwater-surface water interface

    NARCIS (Netherlands)

    van der Grift, Bas; Rozemeijer, Joachim; Griffioen, Jasper; van der Velde, Ype

    2014-01-01

    Eutrophication of freshwater environments following diffuse nutrient loads is a widely recognized water quality problem in catchments. Fluxes of non-point P sources to surface waters originate from surface runoff and flow from soil water and groundwater into surface water. The availability of P in

  9. Cystamine immobilization on TiO{sub 2} film surfaces and the influence on inhibition of collagen-induced platelet activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Yujuan [Key Lab. of Advanced Technology for Materials of Chinese Education Ministry, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Weng Yajun, E-mail: wengyj7032@sohu.com [Key Lab. of Advanced Technology for Materials of Chinese Education Ministry, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhang Liping; Jing Fengjuan; Huang Nan [Key Lab. of Advanced Technology for Materials of Chinese Education Ministry, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Chen Junying, E-mail: chenjy@263.net [Key Lab. of Advanced Technology for Materials of Chinese Education Ministry, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2011-12-15

    Poor haemocompatibility is a main issue of artificial cardiovascular materials in clinical application. Nitric oxide (NO), produced by vascular endothelial cells, is a well known inhibitor of platelet adhesion and activation. Thus, NO-releasing biomaterials are beneficial for improving haemocompatibility of blood-contacting biomedical devices. In this paper, a novel method was developed for enhancement of haemocompatibility by exploiting endogenous NO donors. TiO{sub 2} films were firstly synthesized on Si (1 0 0) wafers via unbalanced magnetron sputtering technology, and then polydopamine was grafted on TiO{sub 2} films and used as a linker for further immobilization of cystamine. The obtained surfaces were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. NO generation is evaluated by saville-griess reagents, and it shows that cystamine immobilized samples are able to catalytically generate NO by decomposing endogenous S-nitrosothiols (RSNO). In vitro platelet adhesion results reveal that cystamine modified surfaces can inhibit collagen-induced platelet activation. ELISA analysis reveals that cGMP in platelets obviously increases on cystamine immobilized surface, which suggests the reducing of platelet activation is through NO/cGMP signal channel. It can be concluded that cystamine immobilized surface shows better blood compatibility by catalyzing NO release from the endogenous NO donor. It may be a promising method for improvement of haemocompatibility of blood-contacting implants.

  10. Immobilization of serum albumin and peptide aptamer for EPC on polydopamine coated titanium surface for enhanced in-situ self-endothelialization

    International Nuclear Information System (INIS)

    Chen, Zhuoyue; Li, Quanli; Chen, Jialong; Luo, Rifang; Maitz, Manfred F.; Huang, Nan

    2016-01-01

    Restenosis and thrombosis are two major complications associated with vascular stents and grafts. The homing of circulating endothelial progenitor cells (EPCs) onto implant surfaces brings a new strategy to solve these problems by accelerating self -endothelialization in situ. Peptide aptamers with high affinity and specific recognition of EPCs can be immobilized to capture EPCs from the circulating blood. In this study, a biotinylated peptide aptamer (TPSLEQRTVYAK-GGGC-K-Biotin) for EPC, and bovine serum albumin (BSA) were co-immobilized onto titanium surface through avidin–biotin recognition to endow the surface with specific affinity for EPC and anti-platelet adhesion properties. Quartz crystal microbalance with dissipation (QCM-D), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and water contact angle measuring were adopted for coating characterization. EPC affinity and hemocompatibility of the coating were also investigated in vitro. The results demonstrated that aptamer and BSA co-immobilized surface significantly reduced platelet adhesion and fibrinogen adsorption/activation. Besides, such functional surface could remarkably enhance EPC adhesion, without affecting the behavior of endothelial cells (ECs) and smooth muscle cells (SMCs) obviously. The result shows the possibility of utilizing such a multifunctional surface in cardiovascular implants. - Highlights: • We construct a multifunctional surface based on immobilization of BSA and aptamer. • It can significantly reduce platelet adhesion and fibrinogen adsorption/activation. • Such functional surface could remarkably enhance EPC adhesion in vitro. • It can induce rapid self-endothelialization of the implant surface in situ in vivo. • It is possible to use such a multifunctional surface in cardiovascular implants.

  11. Immobilization of serum albumin and peptide aptamer for EPC on polydopamine coated titanium surface for enhanced in-situ self-endothelialization

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhuoyue, E-mail: 362947953@qq.com [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu, 610031 (China); RegeMed Lab of Tissue Engineering, Faculty of Life Science, Northwest University, Xi' an, 710069 (China); Li, Quanli [College of Stomology, Anhui Medical University, Hefei, 230032 (China); Chen, Jialong [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu, 610031 (China); College of Stomology, Anhui Medical University, Hefei, 230032 (China); Luo, Rifang [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu, 610031 (China); Maitz, Manfred F. [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu, 610031 (China); Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials, Dresden (Germany); Huang, Nan, E-mail: huangnan1956@163.com [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu, 610031 (China)

    2016-03-01

    Restenosis and thrombosis are two major complications associated with vascular stents and grafts. The homing of circulating endothelial progenitor cells (EPCs) onto implant surfaces brings a new strategy to solve these problems by accelerating self -endothelialization in situ. Peptide aptamers with high affinity and specific recognition of EPCs can be immobilized to capture EPCs from the circulating blood. In this study, a biotinylated peptide aptamer (TPSLEQRTVYAK-GGGC-K-Biotin) for EPC, and bovine serum albumin (BSA) were co-immobilized onto titanium surface through avidin–biotin recognition to endow the surface with specific affinity for EPC and anti-platelet adhesion properties. Quartz crystal microbalance with dissipation (QCM-D), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and water contact angle measuring were adopted for coating characterization. EPC affinity and hemocompatibility of the coating were also investigated in vitro. The results demonstrated that aptamer and BSA co-immobilized surface significantly reduced platelet adhesion and fibrinogen adsorption/activation. Besides, such functional surface could remarkably enhance EPC adhesion, without affecting the behavior of endothelial cells (ECs) and smooth muscle cells (SMCs) obviously. The result shows the possibility of utilizing such a multifunctional surface in cardiovascular implants. - Highlights: • We construct a multifunctional surface based on immobilization of BSA and aptamer. • It can significantly reduce platelet adhesion and fibrinogen adsorption/activation. • Such functional surface could remarkably enhance EPC adhesion in vitro. • It can induce rapid self-endothelialization of the implant surface in situ in vivo. • It is possible to use such a multifunctional surface in cardiovascular implants.

  12. Antibacterial and antibiofilm surfaces through Polydopamine-assisted immobilization of Lysostaphin as an antibacterial enzyme

    Science.gov (United States)

    Antibiotic resistance and the colonization of bacteria on surfaces, often as biofilms, prolong hospitalization periods, increase mortality, and are thus major concerns for health care providers. There is an urgent need for antimicrobial and antibiofilm surface treatments that are semi-permanent, can...

  13. Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

    International Nuclear Information System (INIS)

    ElKaoutit, Mohammed; Naranjo-Rodriguez, Ignacio; Dominguez, Manuel; Hidalgo-Hidalgo-de-Cisneros, Jose Luis

    2011-01-01

    Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its 'native' state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

  14. Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

    Energy Technology Data Exchange (ETDEWEB)

    ElKaoutit, Mohammed, E-mail: elkaoutit@uca.es [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain); Naranjo-Rodriguez, Ignacio [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain); Dominguez, Manuel [Departamento de Fisica de la Materia Condensada, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain); Hidalgo-Hidalgo-de-Cisneros, Jose Luis [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain)

    2011-10-01

    Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its 'native' state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

  15. Study of the surface crystallization and resistance to dissolution of niobium phosphate glasses for nuclear waste immobilization

    International Nuclear Information System (INIS)

    Vieira, Heveline

    2008-01-01

    The surface crystallization and the dissolution rate of three phosphate glass compositions containing different amounts of niobium oxide were studied. The glasses were named Nb30, Nb37, and Nb44 according to the nominal content of niobium oxide in the glass composition. The three compositions were evaluated keeping the P 2 O 5 /K 2 O ratio constant and varying the amount of Nb 2 O 5 . These glasses were produced by melting appropriate chemical compounds at 1500 deg C for 0.5 hour. The crystalline phases which were nucleated on the glass surface after heat treatment were determined by X-ray diffraction. The crystalline structures depend on the amount of niobium oxide in the glass composition. The crystal morphologies were observed by using an optical microscope, and their characteristics are specific for each kind of crystalline phase. The crystal growth rate and the surface nuclei density were determined for each glass composition, and they depend on each crystalline phase nucleated on the surface. From the differential thermal analysis curves it was determined that the Nb44 glass containing 46.5 mol por cent of niobium oxide is the most thermally stable against crystallization when compared to the Nb30 and Nb37 glasses. According to the activation energies determined for crystal growth on the surface of each glass type, the Nb44 glass can also be considered the most resistant one against crystallization. The dissolution rate for the Nb44 glass after 14 days immersed in an aqueous solution with pH equals to 7 at 90 deg C is the lowest (9.0 x 10 -7 g. cm -2 . day -1 ) when compared to the other two glass compositions. The dissolution rates in acidic and neutral solutions of all studied glasses meet the international standards for materials which can be used in the immobilization of nuclear wastes. (author)

  16. Is prolonged immobilization a risk factor for symptomatic venous thromboembolism in elderly bedridden patients? Results of a historical-cohort study.

    Science.gov (United States)

    Gatt, Moshe E; Paltiel, Ora; Bursztyn, Michael

    2004-03-01

    Prolonged immobilization and advanced age are considered to be important risk factors for venous thromboembolism (VTE). Nevertheless, the need for VTE prophylaxis in long-term bedridden patients is not known. To assess whether very prolonged immobilization (i.e. over three months) carries an increased risk for clinically apparent VTE, we performed a historical-cohort study of nursing home residents during a ten-year period. Data concerning patient's mobility and incidence of overt deep vein thrombosis or pulmonary embolism were registered. The mean resident age was 85+/-8.4 years. Eighteen mobile and eight immobile patients were diagnosed with clinically significant thromboembolic events, during 1137 and 573 patient-years of follow up, respectively. The incidence of venous thromboembolic events was similar in both chronically immobilized and mobile patient groups, 13.9 and 15.8 per thousand patient years, respectively (p=0.77). The rate ratio for having a VTE event in the immobilized patient group as compared with the mobile group was 0.88 (95% Confidence Interval (CI) 0.33 to 2.13). When taking into account baseline characteristics, risk factors and death rates by various causes, no differences were found between the two groups. In conclusion, chronically immobile bedridden patients are no more prone to clinically overt venous thromboembolic events than institutionalized mobile patients. Until further studies are performed concerning the impact of very prolonged immobilization on the risk of VTE, there is no evidence to support primary prevention after the first three months of immobilization. Evidence for efficacy or cost effectiveness beyond this early period is not available.

  17. Dynamic Factor Models for the Volatility Surface

    DEFF Research Database (Denmark)

    van der Wel, Michel; Ozturk, Sait R.; Dijk, Dick van

    The implied volatility surface is the collection of volatilities implied by option contracts for different strike prices and time-to-maturity. We study factor models to capture the dynamics of this three-dimensional implied volatility surface. Three model types are considered to examine desirable...

  18. Mass spectrometric investigation of synthetic glycoside of muramyl dipeptide immobilized on fumed silica surface

    Energy Technology Data Exchange (ETDEWEB)

    Kulik, Tetiana V., E-mail: tanyakulyk@gala.net [O.O. Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 Generala Naumova Str., Kyiv 03164 (Ukraine); Azizova, Liana R., E-mail: liana_azizova@ukr.net [O.O. Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 Generala Naumova Str., Kyiv 03164 (Ukraine); Palyanytsya, Borys B. [O.O. Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 Generala Naumova Str., Kyiv 03164 (Ukraine); Zemlyakov, Alexander E.; Tsikalova, Victoria N. [Vernadsky Tauric National University, pr. Akademika Vernadskogo 4, Simferopol, 95007 (Ukraine)

    2010-05-25

    N-Acetylmuramyl-L-alanyl-D-isoglutamine or muramyl dipeptide is a cleavage product of peptidoglycan by lysozyme. This study explored the use of the temperature-programmed desorption mass spectrometry (TPDMS) in analysis of glycoside of muramyl dipeptide: O-{l_brace}(4-tert-butylcyclohexyl)-2-acetamido-2, 3-dideoxy-{beta}-D-glucopyranoside-3-yl{r_brace}-D-lactoyl-L-alanyl-D-isoglutamine (MDP) on the surface of fumed silica. Stages of pyrolysis of MDP in condensed state and on the silica surface have been determined. Three stages have been clear identified under pyrolysis of MDP on the silica surface. Kinetic parameters of thermal reactions on the fumed silica surface and in the condensed state have been calculated.

  19. Immobilization and Natural Attenuation of Arsenic in Surface and Subsurface Sediments

    Science.gov (United States)

    O'Day, P. A.; Illera, V.; Choi, S.; Vlassopoulos, D.

    2008-12-01

    Understanding of molecular-scale biogeochemical processes that control the mobilization and distribution of As and other oxyanions can be used to develop remediation strategies that take advantage of natural geochemical and hydrologic gradients. Arsenic and other toxic oxyanions can be mobilized at low bulk sediment concentrations (ppm range) and thus, treatment technologies are challenged by low contaminant concentrations, widespread sources, variable pH and Eh conditions, and inaccessibility of subsurface environments. In situ chemical amendments to soils and sediments can be used to decrease the mobility and bioaccessibility of As and oxyanions through sorption to, or precipitation with, stabilizing phases. At a site near San Francisco Bay (CA, USA), treatment of As-contaminated soils with sulfate-cement amendments has effectively immobilized As. Laboratory experiments with field soils and spectroscopic characterizations showed that in high pH cement-type treatments, As is precipitated in ettringite-type phases (Ca-Al sulfates), whereas in low pH ferrous sulfate treatments, As is associated with an iron-arsenate phase (angellelite). The presence of As-associated ettringite-type phases in field sediments amended more than a decade ago indicates long-term stability of these neophases, as long as environmental conditions are relatively constant. At sites of subsurface contamination, monitored natural attenuation (MNA) as a remediation approach for As is gaining interest and acceptance. Successful implementation of MNA requires a mechanistic understanding of As sequestration processes and of the subsurface conditions that may enhance or reduce long-term effectiveness. At a former military site (MA, USA), naturally occurring As was mobilized from sediments as a result of reducing conditions from addition of organic carbon as a biodegradation treatment of chlorinated solvents. Elevated As concentrations were not detected further than about 30 m downgradient of the

  20. Effect Factors of Benzene Adsorption and Degradation by Nano-TiO2 Immobilized on Diatomite

    Directory of Open Access Journals (Sweden)

    Lijun Cheng

    2012-01-01

    Full Text Available Difference between adsorption of benzene by diatomite and nano-TiO2 immobilized on diatomite was investigated. And effects of temperature, light intensity, relative humidity, and initial benzene concentration on adsorption and degradation of benzene by nano-TiO2 immobilized on diatomite were also studied. The experimental results showed that when initial benzene concentration was 2.2×10−3 mg L−1, it could be degraded to below safe concentration (1.1×10−4 mg L−1 after 50 h when temperature was 20°C, but it just needed 30 h at 35°C. When light intensity was 6750 Lx, it needed 30 h for benzene to be degraded to below safe concentration, but benzene could barely be degraded without light. When relative humidity was 50%, benzene could be degraded to 1.0×10−4 mg L−1 after 30 h, while its concentration could be reduced to 7.0×10−5 mg L−1 at the relative humidity of 80%.

  1. Immobilized Rhizopus oryzae lipase catalyzed synthesis of palm stearin and cetyl alcohol wax esters: Optimization by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Gargouri Youssef

    2011-06-01

    Full Text Available Abstract Background Waxes are esters of long-chain fatty acids and long-chain alcohols. Their principal natural sources are animals (sperm whale oil and vegetables (jojoba which are expensive and not easily available. Wax esters synthesized by enzymatic transesterification, using palm stearin as raw material, can be considered as an alternative to natural ones. Results Palm stearin is a solid fraction obtained by fractionation of palm oil. Palm stearin was esterified with cetyl alcohol to produce a mixture of wax esters. A non-commercial immobilized lipase from Rhizopus oryzae was used as biocatalyst. Response surface methodology was employed to determine the effects of the temperature (30-50°C, the enzyme concentration (33.34-300 IU/mL, the alcohol/palm stearin molar ratio (3-7 mol/mol and the substrate concentration (0.06-0.34 g/mL on the conversion yield of palm stearin. Under optimal conditions (temperature, 30°C; enzyme concentration, 300 IU/mL; molar ratio 3 and substrate concentration 0.21 g/mL a high conversion yield of 98.52% was reached within a reaction time of 2 h. Conclusions Response surface methodology was successfully applied to determine the optimum operational conditions for synthesis of palm stearin based wax esters. This study may provide useful tools to develop economical and efficient processes for the synthesis of wax esters.

  2. Immobilization of metallothionein to carbon paste electrode surface via anti-MT antibodies and its use for biosensing of silver.

    Science.gov (United States)

    Trnkova, Libuse; Krizkova, Sona; Adam, Vojtech; Hubalek, Jaromir; Kizek, Rene

    2011-01-15

    In this paper, heavy metal biosensor based on immobilization of metallothionein (MT) to the surface of carbon paste electrode (CPE) via anti-MT-antibodies is reported. First, the evaluation of MT electroactivity was done. The attention was focused on the capturing of MT to the CPE surface. Antibodies incorporated and mixed into carbon paste were stable; even after two weeks the observed changes in signal height were lower than 5%. Further, the interaction of MT with polyclonal chicken antibodies incorporated in carbon paste electrode was determined by square-wave voltammetry. In the voltammogram, two signals--labelled as cys(MT) and W(a)--were observed. The cys(MT) corresponded to -SH moieties of MT and W(a) corresponded to tryptophan residues of chicken antibodies. Time of interaction (300 s) and MT concentration (125 μg/ml) were optimized to suggest a silver(I) ions biosensor. Biosensor (CPE modified with anti-MT antibody) prepared under the optimized conditions was then used for silver(I) ions detection. The detection limit (3 S/N) for silver(I) ions was estimated as 0.5 nM. The proposed biosensor was tested by detection spiking of silver(I) ions in various water samples (from very pure distilled water to rainwater). Recoveries varied from 74 to 104%. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Mechanism of the immobilization of surfactants on polymeric surfaces by means of an argon plasma treatment: Influence of UV radiation

    NARCIS (Netherlands)

    Lens, J.P.; Spaay, B.; Terlingen, J.G.A.; Engbers, G.H.M.; Feijen, Jan

    1999-01-01

    The mechanism of the immobilization of the surfactant sodium 10-undecenoate (C11(:)) on poly(ethylene) (PE) by means of an argon plasma treatment has been investigated. In particular, the influence of the vacuum ultraviolet (UV) radiation emitted by the argon plasma on the immobilization was

  4. Tissue factor-expressing tumor cells can bind to immobilized recombinant tissue factor pathway inhibitor under static and shear conditions in vitro.

    Directory of Open Access Journals (Sweden)

    Sara P Y Che

    Full Text Available Mammary tumors and malignant breast cancer cell lines over-express the coagulation factor, tissue factor (TF. High expression of TF is associated with a poor prognosis in breast cancer. Tissue factor pathway inhibitor (TFPI, the endogenous inhibitor of TF, is constitutively expressed on the endothelium. We hypothesized that TF-expressing tumor cells can bind to immobilized recombinant TFPI, leading to arrest of the tumor cells under shear in vitro. We evaluated the adhesion of breast cancer cells to immobilized TFPI under static and shear conditions (0.35 - 1.3 dyn/cm2. We found that high-TF-expressing breast cancer cells, MDA-MB-231 (with a TF density of 460,000/cell, but not low TF-expressing MCF-7 (with a TF density of 1,400/cell, adhered to recombinant TFPI, under static and shear conditions. Adhesion of MDA-MB-231 cells to TFPI required activated factor VII (FVIIa, but not FX, and was inhibited by a factor VIIa-blocking anti-TF antibody. Under shear, adhesion to TFPI was dependent on the TFPI-coating concentration, FVIIa concentration and shear stress, with no observed adhesion at shear stresses greater than 1.0 dyn/cm2. This is the first study showing that TF-expressing tumor cells can be captured by immobilized TFPI, a ligand constitutively expressed on the endothelium, under low shear in vitro. Based on our results, we hypothesize that TFPI could be a novel ligand mediating the arrest of TF-expressing tumor cells in high TFPI-expressing vessels under conditions of low shear during metastasis.

  5. Silk fibroin immobilization on poly(ethylene terephthalate) films: Comparison of two surface modification methods and their effect on mesenchymal stem cells culture

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Meini; Yao, Jinrong; Chen, Xin; Huang, Lei; Shao, Zhengzhong, E-mail: zzshao@fudan.edu.cn

    2013-04-01

    Silk fibroin (SF) has played a curial role for the surface modification of conventional materials to improve the biocompatibility, and SF modified poly(ethylene terephthalate) (PET) materials have potential applications on tissue engineering such as artificial ligament, artificial vessel, artificial heart valve sewing cuffs dacron and surgical mesh engineering. In this work, SF was immobilized onto PET film via two different methods: 1) plasma pretreatment followed by SF dip coating (PET-SF) and 2) plasma-induce acrylic acid graft polymerization and subsequent covalent immobilization of SF on PET film (PET-PAA-SF). It could be found that plasma treatment provided higher surface roughness which was suitable for further SF dip coating, while grafted poly(acrylic acid) (PAA) promised the covalent bonding between SF and PAA. ATR-FTIR adsorption band at 3284 cm{sup −1}, 1623 cm{sup −1} and 1520 cm{sup −1} suggested the successful introduction of SF onto PET surface, while the amount of immobilized SF of PET-SF was higher than PET-PAA-SF according to XPS investigation (0.29 vs 0.23 for N/C ratio). Surface modified PET film was used as substrate for mesenchymal stem cells (MSCs) culture, the cells on PET-SF surface exhibited optimum density compared to PET-PAA-SF according to CCK-8 assays, which indicated that plasma pretreatment followed by SF dip coating was a simple and effective way to prepare biocompatible PET surface. Highlights: ► Silk fibroins were immobilized onto PET films with or without the linker of PAA. ► Various techniques were performed to characterize the modified surfaces ► Plasma treatment followed by SF dip coating introduced more SF onto PET films. ► Compare to PET-PAA-SF, PET-SF has better biocompatibility base on MSCs culture.

  6. Optimization of the production of biodiesel by a commercial immobilized lipase in a solvent-free system using a response surface methodology

    Directory of Open Access Journals (Sweden)

    ZORICA KNEZEVIC

    2008-02-01

    Full Text Available Response surface methodology was used for the evaluation of the effects of various factors on the synthesis of biodiesel catalyzed with immobilized lipase from Rhizomucor miehei in a solvent-free system. The production of biodiesel was optimized and model response equations were obtained, enabling the prediction of biodiesel production from the values of the four main factors. It would seem that the reaction temperature and the amount of water predominantly determined the conversion process while the methanol/oil molar ratio had no significant influence on the reaction rate. The temperature and amount of water showed negative interactive effects on the observed reaction rate per amount of enzyme. However, there were no significant interactions among the other variables according to the test of statistical significance. The highest yield of 10.15 mol kg-1 enzyme was observed at 45 °C with a 6:1 methanol to oil molar ratio and with no added water in the system.

  7. Surface modification of polysulfone membranes applied for a membrane reactor with immobilized alcohol dehydrogenase

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Silau, Harald; Pinelo, Manuel

    2018-01-01

    activated by lithiation followed by functionalization with acid chlorides at 0 °C, permitting modification of commercial PSf membranes without compromising the mechanical integrity of the membrane. Post-functionalization polymer grafting was illustrated through both, a “grafting from” approach by surface...... initiated atom transfer radical polymerization (SI-ATRP) and by a “grafting to” approach exploiting Cu(I) catalyzed 1,3-cycloadditions of alkynes with azides (CuAAC) introducing hydrophilic polymers onto the membrane surface. Poly(1-vinyl imidazole) (pVim) grafted membranes were exploited as support...

  8. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization.

    Science.gov (United States)

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao

    2014-12-10

    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  9. Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application

    OpenAIRE

    Gon?alves, Juliana P L; Shaikh, Afnan Q; Reitzig, Manuela; Kovalenko, Daria A; Michael, Jan; Beutner, Ren?; Cuniberti, Gianaurelio; Scharnweber, Dieter; Opitz, J?rg

    2014-01-01

    Summary Due to their outstanding properties nanodiamonds are a promising nanoscale material in various applications such as microelectronics, polishing, optical monitoring, medicine and biotechnology. Beyond the typical diamond characteristics like extreme hardness or high thermal conductivity, they have additional benefits as intrinsic fluorescence due to lattice defects without photobleaching, obtained during the high pressure high temperature process. Further the carbon surface and its var...

  10. Surface-immobilized hydrogel patterns on length scales from micrometer to nanometer

    Science.gov (United States)

    Zeira, Assaf

    The present work concentrates on the study of pattern generation and transfer processes of monolayer covered surfaces, deriving from the basic working concept of Constructive Lithography. As an advancement of constructive lithography, we developed a direct, one-step printing (contact electrochemical printing, CEP) and replication (contact electrochemical replication, CER) of hydrophilic organic monolayer patterns surrounded by a hydrophobic monolayer background. In addition, we present a process of transfer of metal between two contacting solid surfaces to predefined monolayer template pattern sites (contact electrochemical transfer, CET). This thesis shows that CEP, CER, and CET may be implemented under a variety of different experimental conditions, regardless of whether the initial "master" pattern was created by a parallel (fast) or serial (slow) patterning process. CEP and CER also posses the unique attractive property that each replica may equally function as master stamp in the fabrication of additional replicas. Moreover, due to a mechanism of selfcorrection patterned surfaces produced these process are often free of defects that the initial "master" stamp may had. We finally show that the electrochemical patterning of OTS monolayers on silicon can be further extended to flexible polymeric substrate materials as well as to a variety of chemical manipulations, allowing the fabrication of tridimensional (3D) composite structures made on the basis of readily available OTS compound. The results obtained suggest that such contact electrochemical processes could be used to rapidly generate multiple copies of surface patterns spanning variable length scales, this basic approach being applicable to rigid as well as flexible substrate materials.

  11. Time-resolved imaging and immobilization study of biomaterials on hydrophobic and superhydrophobic surfaces by means of laser-induced forward transfer

    International Nuclear Information System (INIS)

    Boutopoulos, Christos; Chatzipetrou, Marianneza; Zergioti, Ioanna; Papathanasiou, Athanasios G

    2014-01-01

    In this work, we present the generation of high velocity liquid jets of a photosynthetic biomaterial in buffer solution (i.e. thylakoid membranes) and a test solution, using the laser-induced forward transfer (LIFT) technique. The high impact pressure of the collision of the jets on solid substrates, ranging from 0.045 MPa–35 MPa, resulted in strong physical immobilization of the photosynthetic biomaterial on superhydrophobic (SH) poly(methyl methacrylate) (PMMA) surfaces and hydrophobic gold surfaces. The immobilization efficiency was evaluated by fluorescence microscopy, while time-resolved imaging of the LIFT process was carried out to study the corresponding LIFT dynamics. The results show that this simple, direct and chemical-linkers-free immobilization technique is valuable for several biosensors and microfluidic applications since it can be applied to a variety of hydrophobic and SH substrates, leading to the selective immobilization of the biomaterials, due to the high spatial printing resolution of the LIFT technique. (letter)

  12. Novel procedure to enhance PLA surface properties by chitosan irreversible immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Stoleru, Elena; Dumitriu, Raluca Petronela [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley, 41A, 700487 Iasi (Romania); Munteanu, Bogdanel Silvestru [“Al. I. Cuza” University, Faculty of Physics, 11 Carol I Blvd., 700506 Iasi (Romania); Zaharescu, Traian [INCDIE ICPE CA, Bucharest (Romania); Tănase, Elisabeta Elena; Mitelut, Amalia [Industrial Biotechnology Department, Faculty of Biotechnology – USAMV Bucharest (Romania); Ailiesei, Gabriela-Liliana [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley, 41A, 700487 Iasi (Romania); Vasile, Cornelia, E-mail: cvasile@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley, 41A, 700487 Iasi (Romania)

    2016-03-30

    Graphical abstract: - Highlights: • PLA requires functionalization prior to surface attaching chitosan. • Chitosan with different molecular weights was grafted onto PLA surface. • Antibacterial, antifungal, antioxidant PLA-based materials are obtained. • Nano-fibers coatings obtained by electrospinning of high molecular weight chitosan. - Abstract: A novel two step procedure was applied for poly(lactic acid) (PLA) functionalization consisting in the exposure to cold radiofrequency plasma in nitrogen atmosphere or to gamma irradiation followed by “grafting to” of a chitosan layer using carbodiimide chemistry. The adhesion and stability of the deposited surface layer was assured by plasma/gamma irradiation treatment while the chitosan layer offers antifungal/antibacterial/antioxidant activities. Chitosan with different viscosities/deacetylation degree was deposited by electrospinning or immersion methods. Correlations between rheological behavior of chitosan solutions and chitosan layer deposition conditions are made. The PLA surface properties were investigated by water contact angle measurements, ATR-FTIR spectroscopy, AFM, chemiluminiscence, etc. It has been established that the surface roughness increases direct proportional with cold plasma duration and gamma irradiation dose and further increases by chitosan coating which at its turn depends on chitosan characteristics (viscosity and deacetylation degree) and method of deposition. Nano-fibers with relatively homogeneous and reproducible features are obtained by electrospinning of highly viscous chitosan while with the other two types of chitosan both microparticles and nano-fibers are formed. The chitosan coating obtained by immersion is more homogenous and compact and has a better antibacterial activity than the electrospun layer as fiber meshes.

  13. Novel procedure to enhance PLA surface properties by chitosan irreversible immobilization

    Science.gov (United States)

    Stoleru, Elena; Dumitriu, Raluca Petronela; Munteanu, Bogdanel Silvestru; Zaharescu, Traian; Tănase, Elisabeta Elena; Mitelut, Amalia; Ailiesei, Gabriela-Liliana; Vasile, Cornelia

    2016-03-01

    A novel two step procedure was applied for poly(lactic acid) (PLA) functionalization consisting in the exposure to cold radiofrequency plasma in nitrogen atmosphere or to gamma irradiation followed by ;grafting to; of a chitosan layer using carbodiimide chemistry. The adhesion and stability of the deposited surface layer was assured by plasma/gamma irradiation treatment while the chitosan layer offers antifungal/antibacterial/antioxidant activities. Chitosan with different viscosities/deacetylation degree was deposited by electrospinning or immersion methods. Correlations between rheological behavior of chitosan solutions and chitosan layer deposition conditions are made. The PLA surface properties were investigated by water contact angle measurements, ATR-FTIR spectroscopy, AFM, chemiluminiscence, etc. It has been established that the surface roughness increases direct proportional with cold plasma duration and gamma irradiation dose and further increases by chitosan coating which at its turn depends on chitosan characteristics (viscosity and deacetylation degree) and method of deposition. Nano-fibers with relatively homogeneous and reproducible features are obtained by electrospinning of highly viscous chitosan while with the other two types of chitosan both microparticles and nano-fibers are formed. The chitosan coating obtained by immersion is more homogenous and compact and has a better antibacterial activity than the electrospun layer as fiber meshes.

  14. Photochemical cleaving of allochthonous organic-metal complexes contributes to phosphorus immobilization in surface waters

    Czech Academy of Sciences Publication Activity Database

    Porcal, Petr; Frejlachová, K.; Kopáček, Jiří; Nedoma, Jiří; Šavrdová, T.

    2017-01-01

    Roč. 167, JAN (2017), s. 374-381 ISSN 0045-6535 R&D Projects: GA ČR GA15-09721S Institutional support: RVO:60077344 Keywords : photodegradation * dom * phosphorus * aluminum * iron Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.208, year: 2016

  15. Immobilization of enzymes using non-ionic colloidal liquid aphrons (CLAs): Surface and enzyme effects.

    Science.gov (United States)

    Ward, Keeran; Xi, Jingshu; Stuckey, David C

    2015-12-01

    The use of non-ionic colloidal liquid aphrons (CLAs) as a support for enzyme immobilisation was investigated. Formulation required the mixing of an aqueous-surfactant solution with a relatively non-polar solvent-surfactant solution, forming a solvent droplet surrounded by a thin stabilised aqueous film (soapy shell). Studies utilising anionic surfactants have showed increased retention, however, very little have been understood about the forces governing immobilisation. This study seeks to determine the effects of enzyme properties on CLA immobilisation by examining a non-ionic/non-polar solvent system comprised of two non-ionic surfactants, Tween 20 and 80, mineral oil and the enzymes lipase, aprotinin and α-chymotrypsin. From these results it was deduced that hydrophobic interactions strongly governed immobilisation. Confocal Scanning Laser Microscopy (CSLM) revealed that immobilisation was predominantly achieved by surface adsorption attributed to hydrophobic interactions between the enzyme and the CLA surface. Enzyme surface affinity was found to increase when added directly to the formulation (pre-manufacture addition), as opposed to the bulk continuous phase (post-manufacture addition), with α-chymotrypsin and aprotinin being the most perturbed, while lipase was relatively unaffected. The effect of zeta potential on immobilisation showed that enzymes adsorbed better closer to their pI, indicating that charge minimisation was necessary for immobilisation. Finally, the effect of increasing enzyme concentration in the aqueous phase resulted in an increase in adsorption for all enzymes due to cooperativity between protein molecules, with saturation occurring faster at higher adsorption rates. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Surface chemical immobilization of bioactive peptides on synthetic polymers for cardiac tissue engineering.

    Science.gov (United States)

    Rosellini, Elisabetta; Cristallini, Caterina; Guerra, Giulio D; Barbani, Niccoletta

    2015-01-01

    The aim of this work was the development of new synthetic polymeric systems, functionalized by surface chemical modification with bioactive peptides, for myocardial tissue engineering. Polycaprolactone and a poly(ester-ether-ester) block copolymer synthesized in our lab, polycaprolactone-poly(ethylene oxide)-polycaprolactone (PCL-PEO-PCL), were used as the substrates to be modified. Two pentapeptides, H-Gly-Arg-Gly-Asp-Ser-OH (GRGDS) from fibronectin and H-Tyr-Ile-Gly-Ser-Arg-OH (YIGSR) from laminin, were used for the functionalization. Polymeric membranes were obtained by casting from solutions and then functionalized by means of alkaline hydrolysis and subsequent coupling of the bioactive molecules through 1-(3-dimethylaminopropyl)-3-ethylcarbodimide hydrochloride/N-hydroxysuccinimide chemistry. The hydrolysis conditions, in terms of hydrolysis time, temperature, and sodium hydroxide concentration, were optimized for the two materials. The occurrence of the coupling reaction was demonstrated by infrared spectroscopy, as the presence on the functionalized materials of the absorption peaks typical of the two peptides. The peptide surface density was determined by chromatographic analysis and the distribution was studied by infrared chemical imaging. The results showed a nearly homogeneous peptide distribution, with a density above the minimum value necessary to promote cell adhesion. Preliminary in vitro cell culture studies demonstrated that the introduction of the bioactive molecules had a positive effect on improving C2C12 myoblasts growth on the synthetic materials.

  17. Immobilization of poly(MPC) brushes onto titanium surface by combining dopamine self-polymerization and ATRP: Preparation, characterization and evaluation of hemocompatibility in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wenyong; Yang, Ping; Li, Jingan; Li, Shiqi; Li, Peichuang; Zhao, Yuancong, E-mail: Zhaoyc7320@163.com; Huang, Nan

    2015-09-15

    Graphical abstract: The functional surface containing rich amino and hydroxyl groups was obtained by simple and easily dopamine self-polymerization. Poly (MPC) brushes were successfully immobilized on titanium surface by combining acylation reaction and ATRP. This chemical and biomimetic modified titanium surface effectively inhibits platelet adhesion and activation. - Highlights: • Polydopamine coating provides amino and hydroxyl groups for second reactivity. • Poly(MPC) brushes covalently immobilized on coating by surface initiated ATRP. • In vitro hemocompatibility of biomimetic modified Ti was better than unmodified. - Abstract: Poly(2-methacryloyloxyethyl phosphorylcholine(MPC)) has been studied in many biomedical fields because of good biocompatibility, such as hemocompatibility, inhibiting protein adhesion, antifouling, and so on. To achieve good hemocompatibility of titanium (Ti) surface, bio-inspired poly(MPC) brushes were grafted from Ti substrate covalently. In this work, the surface of Ti was first coated with polydopamine, and got a surface bearing −NH{sub 2} and −OH groups which could be bridged with poly(MPC) via atom transfer radical polymerization. Water contact angle decreased to 51.3° when titanium grafted with poly(MPC) brushes. The data of Infrared Spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that poly(MPC) was successfully grafted onto the surface of titanium. Platelet-rich plasma (PRP) adhesion test and lactate dehydrogenase (LDH) assay showed that the number of platelets adhered on the surface of modified-titanium was much less than that of unmodified titanium and platelets did not aggregate and distort. Thus, the simple and chemical method of immobilization of poly(MPC) brushes has potential application for improving hemocompatibility for cardiovascular stent and some other biomaterials.

  18. Enhancement of 6-pentyl-α-pyrone fermentation activity in an extractive liquid-surface immobilization (Ext-LSI) system by mixing anion-exchange resin microparticles.

    Science.gov (United States)

    Oda, Shinobu; Michihata, Sayumi; Sakamoto, Naoki; Horibe, Hideo; Kono, Akihiko; Ohashi, Shinichi

    2012-12-01

    The addition of anion-exchange resin microparticles into a polyacrylonitrile (PAN) ballooned microsphere layer drastically enhanced the fermentative activity of Trichoderma atroviride AG2755-5NM398 in an extractive liquid-surface immobilization (Ext-LSI) system. The production of 6-pentyl-α-pyrone (6PP), a fungicidal secondary metabolite, was 1.92-fold higher than the control (PAN alone). Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. Surface functionalization of superparamagnetic nanoparticles encapsulated by chitosan for protein immobilization; Funcionalizacao da superficie de nanoparticulas superparamagneticas encapsuladas por quitosana para a imobilizacao de proteinas

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Jose Silva de

    2010-07-01

    Nanoscience and nanotechnology have opened up numerous developments of devices and systems on the nanometer scale, with new molecular organization, properties and functions. In this context, the polymeric magnetic nanoparticles are composites formed by magnetic materials with a particle size between 1 and 100 nm combined with functional polymers. They are well-known and have been widely studied because of its applications in various technology areas. Applications on the biological and medical areas include separation and immobilization of enzymes and proteins, improved techniques of magnetic resonance imaging and diagnostic systems for controlled drug delivery. In this work, proteins were immobilized on the surface of a biopolymer combined with superparamagnetic particles of magnetite. The biopolymer chitosan was used, cross-linked and functionalized with glutaraldehyde, applicable to the biological assays. Three types of magnetic composites were obtained, which were called QM1Glu, QM2NaGlu and QM3Glu. They were characterized by X-ray diffraction, scanning electron microscopy, vibrating sample magnetometry, differential scanning calorimetry, thermogravimetry and infrared spectroscopy. They were evaluated concerning the immobilization of the proteins bovine serum albumin (BSA), collagen and trypsin. The study showed that the immobilization of proteins on the biopolymer occurred in 30 min of incubation. The magnetic composite of non functionalized chitosan (QM3) was also evaluated. For trypsin, it was found that the immobilization potential of QM3 was higher than that observed for QM3Glu. After 30 days, the trypsin of the QM3-Trip and QM3Glu-Trip was still with activity. The activity and the enzyme kinetics of the QM3Glu-Trip with the substrate BApNA were demonstrated. (author)

  20. Novel approach for a PTX/VEGF dual drug delivery system in cardiovascular applications-an innovative bulk and surface drug immobilization.

    Science.gov (United States)

    Wulf, Katharina; Teske, Michael; Matschegewski, Claudia; Arbeiter, Daniela; Bajer, Dalibor; Eickner, Thomas; Schmitz, Klaus-Peter; Grabow, Niels

    2018-06-01

    The successive incorporation of several drugs into the polymeric bulk of implants mostly results in loss of considerable quantity of one drug, and/or the loss in quality of the coating and also in changes of drug release time points. A dual drug delivery system (DDDS) based on poly-L-lactide (PLLA) copolymers combining the effective inhibition of smooth muscle cell proliferation while simultaneously promoting re-endothelialization was successfully developed. To overcome possible antagonistic drug interactions and the limitation of the polymeric bulk material as release system for dual drugs, a novel concept which combines the bulk and surface drug immobilization for a DDDS was investigated. The advantage of this DDDS is that the bulk incorporation of fluorescein diacetate (FDAc) (model drug for paclitaxel (PTX)) via spray coating enhanced the subsequent cleavable surface coupling of vascular endothelial growth factor (VEGF) via the crosslinker bissulfosuccinimidyl suberate (BS 3 ). In the presence of the embedded FDAc, the VEGF loading and release are about twice times higher than in absence. Furthermore, the DDDS combines the diffusion drug delivery (FDAc or PTX) and the chemical controlled drug release, VEGF via hydrolysable ester bonds, without loss in quantity and quality of the drug release curves. Additionally, the performed in vitro biocompatibility study showed the bimodal influences of PTX and VEGF on human endothelial EA.hy926 cells. In conclusion, it was possible to show the feasibility to develop a novel DDDS which has a high potential for the medical application due to the possible easy and short modification of a polymer-based PTX delivery system.

  1. Decreased expression of extracellular matrix proteins and trophic factors in the amygdala complex of depressed mice after chronic immobilization stress

    Directory of Open Access Journals (Sweden)

    Jung Soonwoong

    2012-06-01

    Full Text Available Abstract Background The amygdala plays an essential role in controlling emotional behaviors and has numerous connections to other brain regions. The functional role of the amygdala has been highlighted by various studies of stress-induced behavioral changes. Here we investigated gene expression changes in the amygdala in the chronic immobilization stress (CIS-induced depression model. Results Eight genes were decreased in the amygdala of CIS mice, including genes for neurotrophic factors and extracellular matrix proteins. Among these, osteoglycin, fibromodulin, insulin-like growth factor 2 (Igf2, and insulin-like growth factor binding protein 2 (Igfbp2 were further analyzed for histological expression changes. The expression of osteoglycin and fibromodulin simultaneously decreased in the medial, basolateral, and central amygdala regions. However, Igf2 and Igfbp2 decreased specifically in the central nucleus of the amygdala. Interestingly, this decrease was found only in the amygdala of mice showing higher immobility, but not in mice displaying lower immobility, although the CIS regimen was the same for both groups. Conclusions These results suggest that the responsiveness of the amygdala may play a role in the sensitivity of CIS-induced behavioral changes in mice.

  2. Well-oriented ZZ–PS-tag with high Fc-binding onto polystyrene surface for controlled immobilization of capture antibodies

    International Nuclear Information System (INIS)

    Tang, Jin-Bao; Sun, Xi-Feng; Yang, Hong-Ming; Zhang, Bao-Gang; Li, Zhi-Jian; Lin, Zhi-Juan; Gao, Zhi-Qin

    2013-01-01

    Graphical abstract: -- Highlights: •A versatile platform for immobilizing functionally intact IgG is proposed. •The mechanism relies on properly oriented ZZ–PS-tag onto a hydrophilic PS surface. •The oriented ZZ–PS-tag presents ∼fivefold higher IgG-binding activity. •The platform shows tenfold higher sensitivity and a wider linear range in ELISA. -- Abstract: The site specificity and bioactivity retention of antibodies immobilized on a solid substrate are crucial requirements for solid phase immunoassays. A fusion protein between an immunoglobulin G (IgG)-binding protein (ZZ protein) and a polystyrene-binding peptide (PS-tag) was constructed, and then used to develop a simple method for the oriented immobilization of the ZZ protein onto a PS support by the specific attachment of the PS-tag onto a hydrophilic PS. The orientation of intact IgG was achieved via the interaction of the ZZ protein and the constant fragment (Fc), thereby displayed the Fab fragment for binding antigen. The interaction between rabbit IgG anti-horseradish peroxidase (anti-HRP) and its binding partner HRP was analyzed. Results showed that the oriented ZZ–PS-tag yielded an IgG-binding activity that is fivefold higher than that produced by the passive immobilization of the ZZ protein. The advantage of the proposed immunoassay strategy was demonstrated through an enzyme-linked immunosorbent assay, in which monoclonal mouse anti-goat IgG and HRP-conjugated rabbit F(ab′) 2 anti-goat IgG were used to detect goat IgG. The ZZ–PS-tag presented a tenfold higher sensitivity and a wider linear range than did the passively immobilized ZZ protein. The proposed approach may be an attractive strategy for a broad range of applications involving the oriented immobilization of intact IgGs onto PS supports, in which only one type of phi-PS (ZZ–PS-tag) surface is used

  3. Well-oriented ZZ–PS-tag with high Fc-binding onto polystyrene surface for controlled immobilization of capture antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jin-Bao, E-mail: tangjinbao@yahoo.com.cn [School of Pharmacy and Biology, Weifang Medical University, Weifang 261053 (China); Sun, Xi-Feng [Clinical Laboratory, Weifang People' s Hospital, Weifang 261041 (China); Yang, Hong-Ming [School of Pharmacy and Biology, Weifang Medical University, Weifang 261053 (China); Zhang, Bao-Gang [School of Basic Medicine, Weifang Medical University, Weifang 261053 (China); Li, Zhi-Jian [School of Pharmacy and Biology, Weifang Medical University, Weifang 261053 (China); Lin, Zhi-Juan [School of Basic Medicine, Weifang Medical University, Weifang 261053 (China); Gao, Zhi-Qin, E-mail: zhiqingao@yahoo.cn [School of Pharmacy and Biology, Weifang Medical University, Weifang 261053 (China)

    2013-05-07

    Graphical abstract: -- Highlights: •A versatile platform for immobilizing functionally intact IgG is proposed. •The mechanism relies on properly oriented ZZ–PS-tag onto a hydrophilic PS surface. •The oriented ZZ–PS-tag presents ∼fivefold higher IgG-binding activity. •The platform shows tenfold higher sensitivity and a wider linear range in ELISA. -- Abstract: The site specificity and bioactivity retention of antibodies immobilized on a solid substrate are crucial requirements for solid phase immunoassays. A fusion protein between an immunoglobulin G (IgG)-binding protein (ZZ protein) and a polystyrene-binding peptide (PS-tag) was constructed, and then used to develop a simple method for the oriented immobilization of the ZZ protein onto a PS support by the specific attachment of the PS-tag onto a hydrophilic PS. The orientation of intact IgG was achieved via the interaction of the ZZ protein and the constant fragment (Fc), thereby displayed the Fab fragment for binding antigen. The interaction between rabbit IgG anti-horseradish peroxidase (anti-HRP) and its binding partner HRP was analyzed. Results showed that the oriented ZZ–PS-tag yielded an IgG-binding activity that is fivefold higher than that produced by the passive immobilization of the ZZ protein. The advantage of the proposed immunoassay strategy was demonstrated through an enzyme-linked immunosorbent assay, in which monoclonal mouse anti-goat IgG and HRP-conjugated rabbit F(ab′){sub 2} anti-goat IgG were used to detect goat IgG. The ZZ–PS-tag presented a tenfold higher sensitivity and a wider linear range than did the passively immobilized ZZ protein. The proposed approach may be an attractive strategy for a broad range of applications involving the oriented immobilization of intact IgGs onto PS supports, in which only one type of phi-PS (ZZ–PS-tag) surface is used.

  4. Microorganism immobilization

    Science.gov (United States)

    Compere, Alicia L.; Griffith, William L.

    1981-01-01

    Live metabolically active microorganisms are immobilized on a solid support by contacting particles of aggregate material with a water dispersible polyelectrolyte such as gelatin, crosslinking the polyelectrolyte by reacting it with a crosslinking agent such as glutaraldehyde to provide a crosslinked coating on the particles of aggregate material, contacting the coated particles with live microorganisms and incubating the microorganisms in contact with the crosslinked coating to provide a coating of metabolically active microorganisms. The immobilized microorganisms have continued growth and reproduction functions.

  5. New configuration factors for curved surfaces

    International Nuclear Information System (INIS)

    Cabeza-Lainez, Jose M.; Pulido-Arcas, Jesus A.

    2013-01-01

    Curved surfaces have not been thoroughly considered in radiative transfer analysis mainly due to the difficulties arisen in the integration process and perhaps because of the lack of spatial vision of the researchers. It is a fact, especially for architectural lighting, that when concave geometries appear inside a curved space, they are mostly avoided. In this way, a vast repertoire of significant forms is neglected and energy waste is evident. Starting from the properties of volumes enclosed by the minimum number of surfaces, the authors formulate, with little calculus, new simple laws, which enable them to discover a set of configuration factors for caps and various segments of the sphere. The procedure is subsequently extended to previously unimagined surfaces as the paraboloid, the ellipsoid or the cone. Appropriate combination of the said forms with right truncated cones produces several complex volumes, often used in architectural and engineering creations and whose radiative performance could not be accurately predicted for decades. To complete the research, a new method for determining interreflections in curved volumes is also presented. Radiative transfer simulation benefits from these findings, as the simplicity of the results has led the authors to create innovative software more efficient for design and evaluation and applicable to emerging fields like LED lighting. -- Highlights: ► Friendly revision of fundamentals of radiative transfer. ► New configuration factors for curved surfaces obtained without calculus. ► New method for interreflections in curved geometries. ► Enhanced simulation algorithms. ► Fast comparison of radiative performances of surfaces

  6. Immobilization of surface active compounds on polymer supports using glow discharge processess. 1. Sodium dodecyl sulfate on poly(propylene)

    NARCIS (Netherlands)

    Terlingen, J.G.A.; Terlingen, Johannes G.A.; Feijen, Jan; Hoffman, Allan S.

    1993-01-01

    A new method has been developed in which a reversibly adsorbed layer of a surfactant (sodium dodecyl sulfate, SDS) is covalently immobilized in one step onto a hydrophobic substrate (poly(propylene), PP) by applying an argon plasma treatment. The adsorption of SDS from aqueous solutions onto PP

  7. Electrochemical investigations of the interaction of C-reactive protein (CRP) with a CRP antibody chemically immobilized on a gold surface

    International Nuclear Information System (INIS)

    Hennessey, Hooman; Afara, Nadia; Omanovic, Sasha; Padjen, Ante L.

    2009-01-01

    A possibility of using a range of dc and ac electrochemical techniques to probe associative interactions of C-reactive protein (CRP) with CRP antibody (aCRP) immobilized on a gold electrode surface was investigated. It was demonstrated that the investigated electrochemical techniques can be used efficiently to probe these interactions over a wide CRP concentration range, from 1.15 x 10 -5 to 1.15 mg L -1 . The measured sensitivity of the techniques is in the following decreasing order: differential pulse voltammetry, charge-transfer resistance obtained from electrochemical impedance spectroscopy (EIS), cyclic voltammetry, chronoamperometry, and double-layer capacitance deduced from EIS measurements which gave the poorest sensitivity. Measurements of kinetic parameters demonstrated that the associative interactions of CRP with the immobilized aCRP reached quasi-equilibrium after 20-30 min. The kinetics of these interactions was modeled successfully using a two-step kinetic model. In this model, the first step represents reversible CRP-aCRP associative-dissociative interactions, while the second step represents the irreversible transformation of the bound CRP into a thermodynamically stable configuration. It was demonstrated that the thermodynamically stable configuration of CRP starts prevailing after 7 min of interaction of CRP with the immobilized aCRP.

  8. Immobilized yeast in bioreactor for alcohol fermentation

    International Nuclear Information System (INIS)

    Handy, M.K.; Kim, K.

    1986-01-01

    Mutant of Saccharomyces cerevisiae was developed using a Co-60 source. Cells were immobilized onto sterile, channeled alumina beads and packed into bioreactor column under controlled temperature. Feedstocks containing substrate and nutrients were fed into the bioreactor at specific rates. Beads with greatest porosity and surface area produced the most ethanol. Factors affecting ethanol productivity included: temperature, pH, flow rate, nutrients and substrate in the feedstock

  9. One-step immobilization of tris(2,2'-bipyridyl)ruthenium(II) via vapor-surface sol-gel deposition towards solid-state electrochemiluminescence detection

    International Nuclear Information System (INIS)

    Qian Lei; Yang Xiurong

    2008-01-01

    A novel method for immobilization of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy) 3 Cl 2 ) on electrode surfaces based on the vapor-surface sol-gel deposition strategy is first demonstrated in this paper. Ru(bpy) 3 Cl 2 immobilized sol-gel (Ru(bpy) 3 Cl 2 /sol-gel) films were characterized by UV-vis spectroscopy and field-emitted scanning electron microscopy (FE-SEM). These results showed that Ru(bpy) 3 Cl 2 was successfully incorporated into the silica sol-gel film. It was found that many irregular Ru(bpy) 3 Cl 2 /sol-gel clusters were formed on surfaces through one deposition and thick sol-gel films were observed after further deposition. Electrochemical properties and electrochemiluminescence (ECL) behaviors of Ru(bpy) 3 Cl 2 /sol-gel films could be easily adjusted by deposition numbers and time. At last, the Ru(bpy) 3 Cl 2 /sol-gel film modified electrode was used for solid-state ECL detection of tripropylamine. The linear range was from 5.8 x 10 -8 to 2.4 x 10 -4 M with the detection limit of 5 nM, which was three orders of magnitude lower than that from pure Nafion-modified electrodes. The ECL sensor also exhibited high stability, and still remained 92% response after being stored in air for 35 days. This method for immobilization of Ru(bpy) 3 Cl 2 is simple, convenient and low-cost relative to others, so it shows promising applications in solid-state ECL detection

  10. Surface functionalization of copper via oxidative graft polymerization of 2,2'-bithiophene and immobilization of silver nanoparticles for combating biocorrosion.

    Science.gov (United States)

    Wan, Dong; Yuan, Shaojun; Neoh, K G; Kang, E T

    2010-06-01

    An environmentally benign approach to surface modification was developed to impart copper surface with enhanced resistance to corrosion, bacterial adhesion and biocorrosion. Oxidative graft polymerization of 2,2'-bithiophene from the copper surface with self-assembled 2,2'-bithiophene monolayer, and subsequent reduction of silver ions to silver nanoparticles (Ag NPs) on the surface, give rise to a homogeneous bithiophene polymer (PBT) film with densely coupled Ag NPs on the copper surface (Cu-g-PBT-Ag NP surface). The immobilized Ag NPs were found to significantly inhibit bacterial adhesion and enhance the antibacterial properties of the PBT modified copper surface. The corrosion inhibition performance of the functionalized copper substrates was evaluated by Tafel polarization curves and electrochemical impedance spectroscopy. Arising from the chemical affinity of thiols for the noble and coinage metals, the copper surface functionalized with both PBT brushes and Ag NPs also exhibits long-term stability, and is thus potentially useful for combating the combined problems of corrosion and biocorrosion in harsh marine and aquatic environments.

  11. Covalent co-immobilization of heparin/laminin complex that with different concentration ratio on titanium surface for selectively direction of platelets and vascular cells behavior

    International Nuclear Information System (INIS)

    Wang, Jian; Chen, Yuan; Liu, Tao; Wang, Xue; Liu, Yang; Wang, Yuan; Chen, Junying; Huang, Nan

    2014-01-01

    Highlights: • Extracellular matrix inspired surface modification with fibronectin, heparin and VEGF to construct a favorable microenvironment for selectively anticoagulant and promote endothelialization. • Take the advantage of specific intermolecular interaction, the bioactivity of above biomolecules was more efficiently maintained in compared with the common used covalent immobilization method. • Poly-l-lysine was used as a novel interlayer for surface amination, and in comparison, PLL coating was more feasible and the degradation product had no harm to human body. - Abstract: Surface biofunctional modification of coronary artery stent to improve the hemocompatibility and selectively accelerate endothelium regeneration but prevent restenosis have been become a new hotspot. For this, a novel method was developed in this work by co-immobilization of Ln and heparin complex on poly-L-lysine modified Ti surface. Take the advantage of the specific interaction between Ln and heparin, Ln and heparin complexes with different concentration ratios were set up for creating different exposure density of these two types of biomolecules. According to biocompatibility evaluation results, the Hep/Ln complexes modified surface displayed less platelet adhesion and activation. Especially, on L(150)H and L(200)H surface, the AT III binding quantity, APTT value and anti-coagulation property of modified surface were significantly promoted. Furthermore, the adherent density and proliferation activity of ECs and EPCs were positively correlated with Ln concentration. Notably, the proliferation of both ECs and EPCs on L(100)H, L(150)H and L(200)H surface were greatly promoted. Another hand, the proliferation activity of SMCs was significantly inhibited on Hep/Ln modified surfaces, which was considered mainly due to the inhibitory effect of heparin to SMCs. According to the existing results, this study demonstrated that in a certain range of heparin and laminin concentration ratio

  12. Covalent Immobilization of Enoxacin onto Titanium Implant Surfaces for Inhibiting Multiple Bacterial Species Infection and In Vivo Methicillin-Resistant Staphylococcus aureus Infection Prophylaxis.

    Science.gov (United States)

    Nie, Bin'en; Long, Teng; Ao, Haiyong; Zhou, Jianliang; Tang, Tingting; Yue, Bing

    2017-01-01

    Infection is one of the most important causes of titanium implant failure in vivo A developing prophylactic method involves the immobilization of antibiotics, especially vancomycin, onto the surface of the titanium implant. However, these methods have a limited effect in curbing multiple bacterial infections due to antibiotic specificity. In the current study, enoxacin was covalently bound to an amine-functionalized Ti surface by use of a polyethylene glycol (PEG) spacer, and the bactericidal effectiveness was investigated in vitro and in vivo The titanium surface was amine functionalized with 3-aminopropyltriethoxysilane (APTES), through which PEG spacer molecules were covalently immobilized onto the titanium, and then the enoxacin was covalently bound to the PEG, which was confirmed by X-ray photoelectron spectrometry (XPS). A spread plate assay, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to characterize the antimicrobial activity. For the in vivo study, Ti implants were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and implanted into the femoral medullary cavity of rats. The degree of infection was assessed by radiography, micro-computed tomography, and determination of the counts of adherent bacteria 3 weeks after surgery. Our data demonstrate that the enoxacin-modified PEGylated Ti surface effectively prevented bacterial colonization without compromising cell viability, adhesion, or proliferation in vitro Furthermore, it prevented MRSA infection of the Ti implants in vivo Taken together, our results demonstrate that the use of enoxacin-modified Ti is a potential approach to the alleviation of infections of Ti implants by multiple bacterial species. Copyright © 2016 American Society for Microbiology.

  13. Enhanced starch hydrolysis using α-amylase immobilized on cellulose ultrafiltration affinity membrane.

    Science.gov (United States)

    Konovalova, Viktoriia; Guzikevich, Kateryna; Burban, Anatoliy; Kujawski, Wojciech; Jarzynka, Karolina; Kujawa, Joanna

    2016-11-05

    In order to prepare ultrafiltration membranes possessing biocatalytic properties, α-amylase has been immobilized on cellulose membranes. Enzyme immobilization was based on a covalent bonding between chitosan and a surface of cellulose membrane, followed by an attachment of Cibacron Blue F3G-A dye as affinity ligand. Various factors affecting the immobilization process, such as enzyme concentration, pH of modifying solution, zeta-potential of membrane surface, and stability of immobilized enzyme were studied. The applicability of immobilized α-amylase has been investigated in ultrafiltration processes. The immobilization of α-amylase on membrane surface allows to increase the value of mass transfer coefficient and to decrease the concentration polarization effect during ultrafiltration of starch solutions. The enzyme layer on the membrane surface prevents a rapid increase of starch concentration due to the amylase hydrolysis of starch in the boundary layer. The presented affinity immobilization technique allows also for the regeneration of membranes from inactivated enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Development and Validation of an On-Line Water Toxicity Sensor with Immobilized Luminescent Bacteria for On-Line Surface Water Monitoring.

    Science.gov (United States)

    Woutersen, Marjolijn; van der Gaag, Bram; Abrafi Boakye, Afua; Mink, Jan; Marks, Robert S; Wagenvoort, Arco J; Ketelaars, Henk A M; Brouwer, Bram; Heringa, Minne B

    2017-11-22

    Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for example Daphnia magna or Dreissena mussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these biomonitors. Therefore, a new on-line biosensor has been developed, containing immobilized genetically modified bacteria, which respond to genotoxicity in the water by emitting luminescence. The performance of this sensor was tested under laboratory conditions, as well as under field conditions at a monitoring station along the river Meuse in The Netherlands. The sensor was robust and easy to clean, with inert materials, temperature control and nutrient feed for the reporter organisms. The bacteria were immobilized in sol-gel on either an optical fiber or a glass slide and then continuously exposed to water. Since the glass slide was more sensitive and robust, only this setup was used in the field. The sensor responded to spikes of genotoxic compounds in the water with a minimal detectable concentration of 0.01 mg/L mitomycin C in the laboratory and 0.1 mg/L mitomycin C in the field. With further optimization, which should include a reduction in daily maintenance, the sensor has the potential to become a useful addition to the currently available biomonitors.

  15. Development and Validation of an On-Line Water Toxicity Sensor with Immobilized Luminescent Bacteria for On-Line Surface Water Monitoring

    Directory of Open Access Journals (Sweden)

    Marjolijn Woutersen

    2017-11-01

    Full Text Available Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for example Daphnia magna or Dreissena mussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these biomonitors. Therefore, a new on-line biosensor has been developed, containing immobilized genetically modified bacteria, which respond to genotoxicity in the water by emitting luminescence. The performance of this sensor was tested under laboratory conditions, as well as under field conditions at a monitoring station along the river Meuse in The Netherlands. The sensor was robust and easy to clean, with inert materials, temperature control and nutrient feed for the reporter organisms. The bacteria were immobilized in sol-gel on either an optical fiber or a glass slide and then continuously exposed to water. Since the glass slide was more sensitive and robust, only this setup was used in the field. The sensor responded to spikes of genotoxic compounds in the water with a minimal detectable concentration of 0.01 mg/L mitomycin C in the laboratory and 0.1 mg/L mitomycin C in the field. With further optimization, which should include a reduction in daily maintenance, the sensor has the potential to become a useful addition to the currently available biomonitors.

  16. Response surface optimization for the transesterification of karanja oil using immobilized whole cells of Rhizopus oryzae in n-hexane system

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, Devanesan; Rajendran, Aravindan; Thangavelu, Viruthagiri [Annamalai University, Department of Chemical Engineering, Faculty of Engineering and Technology, Biochemical Engineering Laboratory, Annamalai Nagar, Tamil Nadu (India)

    2012-03-15

    Non-edible oils represent one of the most viable alternative feed stocks for the production of large volumes of biodiesel at cheaper cost in tropical countries. The objective of the present study is to investigate the ability of the immobilized whole cells of Rhizopus oryzae MTCC 262 to catalyze the biodiesel production from karanja oil in n-hexane system. Response surface methodology was employed to evaluate the effects of synthesis parameters, such as molar ratio of oil to alcohol, reaction temperature and reaction time on percentage biodiesel (methyl esters) yield. Transesterification was performed in shake flasks containing immobilized cells in the reaction mixture with 10% oil weight of n-hexane. The quadratic effects of molar ratio of oil to alcohol and reaction time proved to be the significant at 1% and 5% levels, respectively. The optimum synthesis conditions were found to be: molar ratio of oil to alcohol 1:2.73, reaction temperature 41.39 C and reaction time 73.97 h. Biodiesel yield (methyl ester) was 75.98 (wt.%) under the optimal conditions and the subsequent verification experiments with biodiesel yield of 78.0 (wt.%) confirmed the validity of the proposed model. (orig.)

  17. Immobilization of lipases on alkyl silane modified magnetic nanoparticles: effect of alkyl chain length on enzyme activity.

    Directory of Open Access Journals (Sweden)

    Jiqian Wang

    Full Text Available BACKGROUND: Biocatalytic processes often require a full recycling of biocatalysts to optimize economic benefits and minimize waste disposal. Immobilization of biocatalysts onto particulate carriers has been widely explored as an option to meet these requirements. However, surface properties often affect the amount of biocatalysts immobilized, their bioactivity and stability, hampering their wide applications. The aim of this work is to explore how immobilization of lipases onto magnetite nanoparticles affects their biocatalytic performance under carefully controlled surface modification. METHODOLOGY/PRINCIPAL FINDINGS: Magnetite nanoparticles, prepared through a co-precipitation method, were coated with alkyl silanes of different alkyl chain lengths to modulate their surface hydrophobicity. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through hydrophobic interaction. Enzyme activity was assessed by catalytic hydrolysis of p-nitrophenyl acetate. The activity of immobilized lipases was found to increase with increasing chain length of the alkyl silane. Furthermore, the catalytic activities of lipases immobilized on trimethoxyl octadecyl silane (C18 modified Fe(3O(4 were a factor of 2 or more than the values reported from other surface immobilized systems. After 7 recycles, the activities of the lipases immobilized on C18 modified nanoparticles retained 65%, indicating significant enhancement of stability as well through hydrophobic interaction. Lipase immobilized magnetic nanoparticles facilitated easy separation and recycling with high activity retaining. CONCLUSIONS/SIGNIFICANCE: The activity of immobilized lipases increased with increasing alkyl chain length of the alkyl trimethoxy silanes used in the surface modification of magnetite nanoparticles. Lipase stability was also improved through hydrophobic interaction. Alkyl silane modified magnetite nanoparticles are thus highly attractive carriers for

  18. Immobilization of lipases on alkyl silane modified magnetic nanoparticles: effect of alkyl chain length on enzyme activity.

    Science.gov (United States)

    Wang, Jiqian; Meng, Gang; Tao, Kai; Feng, Min; Zhao, Xiubo; Li, Zhen; Xu, Hai; Xia, Daohong; Lu, Jian R

    2012-01-01

    Biocatalytic processes often require a full recycling of biocatalysts to optimize economic benefits and minimize waste disposal. Immobilization of biocatalysts onto particulate carriers has been widely explored as an option to meet these requirements. However, surface properties often affect the amount of biocatalysts immobilized, their bioactivity and stability, hampering their wide applications. The aim of this work is to explore how immobilization of lipases onto magnetite nanoparticles affects their biocatalytic performance under carefully controlled surface modification. Magnetite nanoparticles, prepared through a co-precipitation method, were coated with alkyl silanes of different alkyl chain lengths to modulate their surface hydrophobicity. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through hydrophobic interaction. Enzyme activity was assessed by catalytic hydrolysis of p-nitrophenyl acetate. The activity of immobilized lipases was found to increase with increasing chain length of the alkyl silane. Furthermore, the catalytic activities of lipases immobilized on trimethoxyl octadecyl silane (C18) modified Fe(3)O(4) were a factor of 2 or more than the values reported from other surface immobilized systems. After 7 recycles, the activities of the lipases immobilized on C18 modified nanoparticles retained 65%, indicating significant enhancement of stability as well through hydrophobic interaction. Lipase immobilized magnetic nanoparticles facilitated easy separation and recycling with high activity retaining. The activity of immobilized lipases increased with increasing alkyl chain length of the alkyl trimethoxy silanes used in the surface modification of magnetite nanoparticles. Lipase stability was also improved through hydrophobic interaction. Alkyl silane modified magnetite nanoparticles are thus highly attractive carriers for enzyme immobilization enabling efficient enzyme recovery and recycling.

  19. Linker-free covalent immobilization of heparin, SDF-1α, and CD47 on PTFE surface for antithrombogenicity, endothelialization and anti-inflammation.

    Science.gov (United States)

    Gao, Ang; Hang, Ruiqiang; Li, Wan; Zhang, Wei; Li, Penghui; Wang, Guomin; Bai, Long; Yu, Xue-Feng; Wang, Huaiyu; Tong, Liping; Chu, Paul K

    2017-09-01

    Small-diameter vascular grafts made of biomedical polytetrafluoroethylene (PTFE) suffer from the poor long-term patency rate originating from thrombosis and intimal hyperplasia, which can be ascribed to the insufficient endothelialization and chronic inflammation of the materials. Hence, bio-functionalization of PTFE grafts is highly desirable to circumvent these disadvantages. In this study, a versatile "implantation-incubation" approach in which the biomedical PTFE is initially modified by plasma immersion ion implantation (PIII) is described. After the N 2 PIII treatment, the surface of biomedical PTFE is roughened with nanostructures and more importantly, the abundant free radicals generated underneath the surface continuously migrate to the surface and react with environmental molecules. Taking advantage of this mechanism, various biomolecules with different functions can be steadily immobilized on the surface of PTFE by simple solution immersion. As examples, three typical biomolecules, heparin, SDF-1α, and CD47, are covalently grafted onto the PTFE. In addition to retaining the bioactivity, the surface-functionalized PTFE exhibits reduced thrombogenicity, facilitates the recruitment of endothelial progenitor cells, and even alleviates the inflammatory immune responses of monocytes-macrophages and is thus promising to the development of small-diameter prosthetic vascular grafts with good long-term patency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Surface water quality assessment using factor analysis

    African Journals Online (AJOL)

    2006-01-16

    Jan 16, 2006 ... Surface water, groundwater quality assessment and environ- .... Urbanisation influences the water cycle through changes in flow and water ..... tion of aquatic life, CCME water quality Index 1, 0. User`s ... Water, Air Soil Pollut.

  1. Factors influencing surface roughness of polyimide film

    International Nuclear Information System (INIS)

    Yao Hong; Zhang Zhanwen; Huang Yong; Li Bo; Li Sai

    2011-01-01

    The polyimide (PI) films of pyromellitic dianhydride-oxydiamiline (PMDA-ODA) were fabricated using vapor deposition polymerization (VDP) method under high vacuum pressure of 10-4 Pa level. The influence of equipment, substrate temperature, the process of heating and deposition ratio of monomers on the surface roughness of the PI films was investigated. The surface topography of films was measured by interferometer microscopy and scanning electron microscopy(SEM), and the surface roughness was probed with atomic force microscopy(AFM). The results show that consecutive films can be formed when the distance from steering flow pipe to substrate is 74 cm. The surface roughnesses are 291.2 nm and 61.9 nm respectively for one-step heating process and multi-step heating process, and using fine mesh can effectively avoid the splash of materials. The surface roughness can be 3.3 nm when the deposition rate ratio of PMDA to ODA is 0.9:1, and keeping the temperature of substrate around 30 degree C is advantageous to form a film with planar micro-surface topography. (authors)

  2. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Godoy-Gallardo, Maria, E-mail: maria.godoy.gallardo@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Guillem-Marti, Jordi, E-mail: jordi.guillem.marti@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Sevilla, Pablo, E-mail: psevilla@euss.es [Department of Mechanics, Escola Universitària Salesiana de Sarrià (EUSS), C/ Passeig de Sant Bosco, 42, 08017 Barcelona (Spain); Manero, José M., E-mail: jose.maria.manero@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Gil, Francisco J., E-mail: francesc.xavier.gil@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); and others

    2016-02-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  3. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    International Nuclear Information System (INIS)

    Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M.; Gil, Francisco J.

    2016-01-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  4. Surface sensitivity of nuclear-knock-out form factors

    International Nuclear Information System (INIS)

    Fratamico, G.

    1984-01-01

    A numerical calculation has been performed to investigate the sensitivity of nuclear-knock-out form factors to nuclear-surface behaviour of bound-state wave functions. The result of our investigation suggests that one can extract the bound-state behaviour at the surface from experimental information on nuclear-knock-out form factors

  5. Immobilization of Styrene-acrylamide Co-polymer on Either Silica Particles or Inner Surface of Silica Capillary for the Separation of D-Glucose Anomers

    International Nuclear Information System (INIS)

    Ali, Faiz; Kim, Yune Sung; Cheong, Won Jo

    2014-01-01

    Styrene-acrylamide co-polymer was immobilized on porous partially sub-2 μm silica monolith particles and inner surface of fused silica capillary (50 μm ID and 28 cm length) to result in μLC and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant μLC and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/ 25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW∼1500) with good separation efficiency (number of theoretical plates ∼300,000/m)

  6. Immobilization of Styrene-acrylamide Co-polymer on Either Silica Particles or Inner Surface of Silica Capillary for the Separation of D-Glucose Anomers

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Faiz; Kim, Yune Sung; Cheong, Won Jo [Inha Univ., Incheon (Korea, Republic of)

    2014-02-15

    Styrene-acrylamide co-polymer was immobilized on porous partially sub-2 μm silica monolith particles and inner surface of fused silica capillary (50 μm ID and 28 cm length) to result in μLC and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant μLC and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/ 25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW∼1500) with good separation efficiency (number of theoretical plates ∼300,000/m)

  7. Effective surface modification of MnFe2O4@SiO2@PMIDA magnetic nanoparticles for rapid and high-density antibody immobilization

    Science.gov (United States)

    Rashid, Zahra; Soleimani, Masoud; Ghahremanzadeh, Ramin; Vossoughi, Manouchehr; Esmaeili, Elaheh

    2017-12-01

    The present study is aimed at the synthesis of MnFe2O4@SiO2@PMIDA in terms of highly efficient sensing platform for anti-prostate specific membrane antigen (PSMA) immobilization. Superparamagnetic manganese ferrite nanoparticles were synthesized following co-precipitation method and then SiO2 shell was coated on the magnetic core with tetraethyl orthosilicate (TEOS) through a silanization reaction to prevent oxidation, agglomeration and, increase the density of OH groups on the surface of MnFe2O4. Subsequently, MnFe2O4@SiO2@PMIDA obtained as a result of the reaction between N-(phosphonomethyl)iminodiacetic acid (PMIDA) and MnFe2O4@SiO2. The reactive carboxyl groups on the surface of magnetic nanoparticles can efficiently conjugate to a monoclonal antibody, specific to PSMA, which was confirmed by enzyme-linked immune sorbent assay (ELISA). Thus, this kind of functionalized magnetic nanoparticles is promising to be utilized in the improvement of ELISA-based biosensors and also will be effective in a variety of biomedical applications such as cell separation, diagnosis, and monitoring of human diseases.

  8. Strong and Reversible Monovalent Supramolecular Protein Immobilization

    NARCIS (Netherlands)

    Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

    2010-01-01

    Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

  9. Chondrogenesis and hypertrophy in response to aggregate behaviors of human mesenchymal stem cells on a dendrimer-immobilized surface.

    Science.gov (United States)

    Wongin, Sopita; Ogawa, Yuuki; Kim, Mee-Hae; Viravaidya-Pasuwat, Kwanchanok; Kino-Oka, Masahiro

    2017-08-01

    To investigate the behaviors of aggregates of human mesenchymal stem cells (hMSCs) on chondrogenesis and chondrocyte hypertrophy using spatiotemporal expression patterns of chondrogenic (type II collagen) and hypertrophic (type X collagen) markers during chondrogenesis. hMSCs were cultured on either a polystyrene surface or polyamidoamine dendrimer surface with a fifth generation (G5) dendron structure in chondrogenic medium and growth medium. At day 7, cell aggregates without stress fibers formed on the G5 surface and triggered differentiation of hMSCs toward the chondrogenic fate, as indicated by type II collagen being observed while type X collagen was undetectable. In contrast, immunostaining of hMSCs cultured on polystyrene, which exhibited abundant stress fibers and did not form aggregates, revealed no evidence of either type II and or type X collagen. At day 21, the morphological changes of the cell aggregates formed on the G5 surface were suppressed as a result of stress fiber formation. Type II collagen was observed throughout the aggregates whereas type X collagen was detected only at the basal side of the aggregates. Change of cell aggregate behaviors derived from G5 surface alone regulated chondrogenesis and hypotrophy, and this was enhanced by chondrogenic medium. Incubation of hMSCs affects the expression of type II and X collagens via effects on cell aggregate behavior and stress fiber formation.

  10. Factors influencing graphene growth on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Loginova, E; Bartelt, N C; McCarty, K F [Sandia National Laboratories, Livermore, CA (United States); Feibelman, P J [Sandia National Laboratories, Albuquerque, NM (United States)], E-mail: mccarty@sandia.gov

    2009-06-15

    Graphene forms from a relatively dense, tightly bound C-adatom gas when elemental C is deposited on or segregates to the Ru(0001) surface. Nonlinearity of the graphene growth rate with C-adatom density suggests that growth proceeds by addition of C atom clusters to the graphene edge. The generality of this picture has now been studied by use of low-energy electron microscopy (LEEM) to observe graphene formation when Ru(0001) and Ir(111) surfaces are exposed to ethylene. The finding that graphene growth velocities and nucleation rates on Ru have precisely the same dependence on adatom concentration as for elemental C deposition implies that hydrocarbon decomposition only affects graphene growth through the rate of adatom formation. For ethylene, that rate decreases with increasing adatom concentration and graphene coverage. Initially, graphene growth on Ir(111) is like that on Ru: the growth velocity is the same nonlinear function of adatom concentration (albeit with much smaller equilibrium adatom concentrations, as we explain with DFT calculations of adatom formation energies). In the later stages of growth, graphene crystals that are rotated relative to the initial nuclei nucleate and grow. The rotated nuclei grow much faster. This difference suggests firstly, that the edge-orientation of the graphene sheets relative to the substrate plays an important role in the growth mechanism, and secondly, that attachment of the clusters to the graphene is the slowest step in cluster addition, rather than formation of clusters on the terraces.

  11. Immobilization increases interleukin-6, but not tumour necrosis factor-a, release from the leg during exercise in humans

    DEFF Research Database (Denmark)

    Reihmane, Dace; Hansen, Andreas Vigelsø; Jensen, Martin Gram

    2013-01-01

    have now studied the temporal relationship of leg IL-6 and TNF-a release before and during isolated two-legged exercise after 14 days of one-leg immobilization (IM) while the other leg served as the control (CON) leg. Fifteen healthy male subjects (mean ± SEM age, 23 ± 1 years; body mass index, 23.......6 ± 0.7 kg m; and maximal oxygen uptake, 46.8 ± 1.4 ml kg min) performed 45 min of two-legged dynamic knee-extensor exercise at 19.6 ± 0.8 W. Arterial and femoral venous blood samples from the CON and the IM leg were collected every 15 min during exercise, and leg blood flow was measured with Doppler...

  12. SU-F-T-640: Feasibility of Using a Commercially Available Surface Guided Radiotherapy System with An Open-Face SRS Immobilization System

    Energy Technology Data Exchange (ETDEWEB)

    Chinsky, B; Patel, R; Roeske, J; Surucu, M [Loyola University Medical Center, Maywood, IL (United States)

    2016-06-15

    Purpose: To evaluate the inherent accuracy of using a surface guided radiotherapy system (SGRT) in the setup and monitoring of patients receiving stereotactic radiosurgery with an open-face SRS immobilization system. Methods: An anthropomorphic head phantom was set up using the Qfix Encompass SRS Immobilization System on a Varian Edge with OSMS and Varian TrueBeam with AlignRT. The phantom was positioned at 0° gantry and couch. A reference image was acquired using the SGRT system and an ROI was created over the mask opening. The couch and gantry were rotated to different combinations focusing on clinically used SRS gantry/couch combinations and those blocking the SGRT cameras. Perceived surface deviation by the SGRT system from the reference image was recorded. A Winston-Lutz test was performed on couch angles tested and used to exclude couch walkout. The deviation magnitude was calculated using translational values and rotational raw values were recorded. Results: The maximum couch walkouts were: 0.4mm (Edge) and 0.5mm (TB). Solely rotating the gantry resulted in a median couch deviation of 0.2mm and range of 0.1–0.3mm for both linacs. Only rotating the couch (0° gantry) resulted in median deviations of 0.6mm and 0.5mm with ranges of 0.3–1.0mm and 0.3–0.7mm for the Edge and TB, respectively. Combining gantry and couch rotations, the median deviations were 0.7mm and 0.9mm with ranges of 0.3–1.1mm and 0.2–1.9mm for the Edge and TB, respectively. Including all combinations, rotation, roll, and pitch median deviations ranged from 0.1–0.3° with pitch demonstrating consistently higher values and a maximum deviation of 1.0° (both linacs). Conclusion: SGRT is a reliable monitoring tool, though taking into account system fluctuations, 1mm is too restrictive a site tolerance to use with the Qfix Encompass mask. Gantry rotation has little effect on system fluctuation even with camera blockage, whereas couch rotation has a larger effect.

  13. SU-F-T-640: Feasibility of Using a Commercially Available Surface Guided Radiotherapy System with An Open-Face SRS Immobilization System

    International Nuclear Information System (INIS)

    Chinsky, B; Patel, R; Roeske, J; Surucu, M

    2016-01-01

    Purpose: To evaluate the inherent accuracy of using a surface guided radiotherapy system (SGRT) in the setup and monitoring of patients receiving stereotactic radiosurgery with an open-face SRS immobilization system. Methods: An anthropomorphic head phantom was set up using the Qfix Encompass SRS Immobilization System on a Varian Edge with OSMS and Varian TrueBeam with AlignRT. The phantom was positioned at 0° gantry and couch. A reference image was acquired using the SGRT system and an ROI was created over the mask opening. The couch and gantry were rotated to different combinations focusing on clinically used SRS gantry/couch combinations and those blocking the SGRT cameras. Perceived surface deviation by the SGRT system from the reference image was recorded. A Winston-Lutz test was performed on couch angles tested and used to exclude couch walkout. The deviation magnitude was calculated using translational values and rotational raw values were recorded. Results: The maximum couch walkouts were: 0.4mm (Edge) and 0.5mm (TB). Solely rotating the gantry resulted in a median couch deviation of 0.2mm and range of 0.1–0.3mm for both linacs. Only rotating the couch (0° gantry) resulted in median deviations of 0.6mm and 0.5mm with ranges of 0.3–1.0mm and 0.3–0.7mm for the Edge and TB, respectively. Combining gantry and couch rotations, the median deviations were 0.7mm and 0.9mm with ranges of 0.3–1.1mm and 0.2–1.9mm for the Edge and TB, respectively. Including all combinations, rotation, roll, and pitch median deviations ranged from 0.1–0.3° with pitch demonstrating consistently higher values and a maximum deviation of 1.0° (both linacs). Conclusion: SGRT is a reliable monitoring tool, though taking into account system fluctuations, 1mm is too restrictive a site tolerance to use with the Qfix Encompass mask. Gantry rotation has little effect on system fluctuation even with camera blockage, whereas couch rotation has a larger effect.

  14. End-Point Immobilization of Recombinant Thrombomodulin via Sortase-Mediated Ligation

    Science.gov (United States)

    Jiang, Rui; Weingart, Jacob; Zhang, Hailong; Ma, Yong; Sun, Xue-Long

    2012-01-01

    We report an enzymatic end-point modification and immobilization of recombinant human thrombomodulin (TM), a cofactor for activation of anticoagulant protein C pathway via thrombin. First, a truncated TM mutant consisting of epidermal growth factor-like domains 4–6 (TM456) with a conserved pentapeptide LPETG motif at its C-terminal was expressed and purified in E. coli. Next, the truncated TM456 derivative was site-specifically modified with N-terminal diglycine containing molecules such as biotin and the fluorescent probe dansyl via sortase A (SrtA) mediated ligation (SML). The successful ligations were confirmed by SDS-PAGE and fluorescence imaging. Finally, the truncated TM456 was immobilized onto N-terminal diglycine-functionalized glass slide surface via SML directly. Alternatively, the truncated TM456 was biotinylated via SML and then immobilized onto streptavidin-functionalized glass slide surface indirectly. The successful immobilizations were confirmed by fluorescence imaging. The bioactivity of the immobilized truncated TM456 was further confirmed by protein C activation assay, in which enhanced activation of protein C by immobilized recombinant TM was observed. The sortase A-catalyzed surface ligation took place under mild conditions and is rapid occurring in a single step without prior chemical modification of the target protein. This site-specific covalent modification leads to molecules being arranged in a definitively ordered fashion and facilitating the preservation of the protein’s biological activity. PMID:22372933

  15. Different Interfacial Behaviors of N- and C-Terminus Cysteine-Modified Cecropin P1 Chemically Immobilized onto Polymer Surface

    Science.gov (United States)

    2013-08-06

    Anderson, G. P.; Ligler, F. S.; Shaffer, K. M.; Taitt, C. R. Antimicrobial peptides: New recognition molecules for detecting botulinum toxins ...as a biosensor for rapid detection of pathogens and toxins . Lab. Invest. 2007, 88 (2), 196−206. (20) Jonkheijm, P.; Weinrich, D.; Schröder, H...optics; Wiley-Interscience: New York, 1984; Vol. 575, p 1. (43) Shen, Y. R. Surface properties probed by second-harmonic and sum-frequency generation

  16. Sol-gel preparation of high surface area potassium tetratitanate for the immobilization of nuclear waste metal ions

    International Nuclear Information System (INIS)

    Jung, K.T.; Shul, Y.G.; Moon, J.K.; Oh, W.J.

    1997-01-01

    Potassium tetratinates(K 2 Ti 4 O 9 ) were synthesized by using the sol-gel method to produce ion-exchangeable materials with high surface area. The effects of mole ratios of K/Ti and H 2 O/Ti were examined. K 2 Ti 4 O 9 was obtained at 740 deg. C by the sol-gel method, which uses a lower temperature than the melting method. After calcination at 800 deg. C, K 2 Ti 4 O exhibits a needle shape which is quite different from the shape of K 2 Ti 6 O 13 powder. The surface areas of K 2 Ti 4 O 9 was 15 m 2 /g by the sol-gel method after calcining at 800 C. The enhancement of BET area to 25 m 2 /g was obtained after supercritical drying using EtOH as solvent. By using the sodium alginate method, needle type potassium titanate 10μm in length, the longest aspect ratio of 1,3 x 10 3 could be obtained. There are variations in the Sr 2+ ion exchange rate and capacity according to the preparation method. Larger BET surface area provides fast ion exchange and larger capacity for Sr 2+ ion in the order; sol-gel process with supercritical drying > sol-gel process > melting process. (author). 17 refs, 21 figs, 1 tab

  17. A simple fabrication of plasmonic surface-enhanced Raman scattering (SERS) substrate for pesticide analysis via the immobilization of gold nanoparticles on UF membrane

    Science.gov (United States)

    Hong, Jangho; Kawashima, Ayato; Hamada, Noriaki

    2017-06-01

    In this study, we developed a facile fabrication method to access a highly reproducible plasmonic surface enhanced Raman scattering substrate via the immobilization of gold nanoparticles on an Ultrafiltration (UF) membrane using a suction technique. This was combined with a simple and rapid analyte concentration and detection method utilizing portable Raman spectroscopy. The minimum detectable concentrations for aqueous thiabendazole standard solution and thiabendazole in orange extract are 0.01 μg/mL and 0.125 μg/g, respectively. The partial least squares (PLS) regression plot shows a good linear relationship between 0.001 and 100 μg/mL of analyte, with a root mean square error of prediction (RMSEP) of 0.294 and a correlation coefficient (R2) of 0.976 for the thiabendazole standard solution. Meanwhile, the PLS plot also shows a good linear relationship between 0.0 and 2.5 μg/g of analyte, with an RMSEP value of 0.298 and an R2 value of 0.993 for the orange peel extract. In addition to the detection of other types of pesticides in agricultural products, this highly uniform plasmonic substrate has great potential for application in various environmentally-related areas.

  18. immobilization of sheep anti-T3 antibodies on the surface of filter paper discs and use it as a solid phase for detection of triiodothyronine

    International Nuclear Information System (INIS)

    Moustafa, K.A.

    2010-01-01

    immunoassays are the most widely used analytical techniques and have been successfully applied to an extensive range of substances including both large and small molecules, cellular components and viruses. the present study describes the development and validation of a sensitive and specific radioimmunoassay (RIA) for triiodothyronine hormone (T 3 ) quantification using purified anti-T 3 antibodies which immobilized onto the surface of filter paper discs and acts as a solid phase anti-T 3 . also, the purified triiodothyronine was used for tracer and standard preparation. the T 3 -tracer was prepared by using chloramine-T method for iodination of purified T 3 with radio labeled iodine -125. the assay allowed to measure serum T 3 hormone levels with a sensitivity of 0.16 ng/ml. serial T 3 serum sample dilutions were linear. the recovery of T 3 from T 3 serum samples ranged from 83.87 % to 116.1 %. there was a tight correlation between T 3 values measured by the prepared system and by that of commercially available T 3 -RIA kit. in conclusion, the prepared T 3 -RIA system was sensitive, linear, accurate, precise and reproducible.

  19. Functionalizable surface platform with reduced nonspecific protein adsorption from bull blood plasma - Material selection and protein immobilization optimization

    Czech Academy of Sciences Publication Activity Database

    Vaisocherová, Hana; Zhang, Z.; Yang, W.; Cao, Z.; Cheng, G.; Taylor, A. D.; Piliarik, Marek; Homola, Jiří; Jiang, S.

    2009-01-01

    Roč. 24, č. 7 (2009), s. 1924-1930 ISSN 0956-5663 R&D Projects: GA AV ČR KAN200670701 Institutional research plan: CEZ:AV0Z20670512 Keywords : Zwitterionic poly(carboxybetaine) * Functionalization * Ultra-low fouling Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.429, year: 2009

  20. QM/MM and classical molecular dynamics simulation of histidine-tagged peptide immobilization on nickel surface

    Energy Technology Data Exchange (ETDEWEB)

    Yang Zhenyu [State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080(China); Zhao Yapu [State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: yzhao@lnm.imech.ac.cn

    2006-05-15

    The hybrid quantum mechanics (QM) and molecular mechanics (MM) method is employed to simulate the His-tagged peptide adsorption to ionized region of nickel surface. Based on the previous experiments, the peptide interaction with one Ni ion is considered. In the QM/MM calculation, the imidazoles on the side chain of the peptide and the metal ion with several neighboring water molecules are treated as QM part calculated by 'GAMESS', and the rest atoms are treated as MM part calculated by 'TINKER'. The integrated molecular orbital/molecular mechanics (IMOMM) method is used to deal with the QM part with the transitional metal. By using the QM/MM method, we optimize the structure of the synthetic peptide chelating with a Ni ion. Different chelate structures are considered. The geometry parameters of the QM subsystem we obtained by QM/MM calculation are consistent with the available experimental results. We also perform a classical molecular dynamics (MD) simulation with the experimental parameters for the synthetic peptide adsorption on a neutral Ni(1 0 0) surface. We find that half of the His-tags are almost parallel with the substrate, which enhance the binding strength. Peeling of the peptide from the Ni substrate is simulated in the aqueous solvent and in vacuum, respectively. The critical peeling forces in the two environments are obtained. The results show that the imidazole rings are attached to the substrate more tightly than other bases in this peptide.

  1. Electrochemical and electrocatalytic studies of toluidine blue immobilized on a silica gel surface coated with niobium oxide

    Directory of Open Access Journals (Sweden)

    Santos Antonio S.

    2002-01-01

    Full Text Available The electrochemical behavior of toluidine blue (TB adsorbed on a silica surface modified with niobium oxide (SN was investigated using a modified carbon paste electrode. The presence of SN gave the electrode high stability, avoiding the leaching out of the mediator from the electrode surface. The formal potential (E0' of the adsorbed TB was --113 mV vs. SCE, indicating a shift of almost 100 mV towards more positive potential values, compared to TB dissolved in aqueous solution or adsorbed on carbon paste. The stability and formal potential remained constant upon changing the solution pH in the range 5 to 8. In these solution pH values the electrocatalytic activity remained almost constant with a sensitivity of 1.2 10-4 A L mol-1 cm-2 and a K Mapp of 4.9 10-5 mol L-1. A linear response range for NADH concentration between 2.0 10-4 and 4.0 10-3 mol L-1 at pH 7.0, with a detection limit of 3.4 10-5 mol L-1 was observed for the sensor. A response time of 2 s and a precision of 1.0 %, expressed as relative standard deviation for 10 replicates, were observed for the sensor developed.

  2. Maskless Surface Modification of Polyurethane Films by an Atmospheric Pressure He/O2 Plasma Microjet for Gelatin Immobilization

    Directory of Open Access Journals (Sweden)

    Man Zhang

    2018-04-01

    Full Text Available A localized maskless modification method of polyurethane (PU films through an atmospheric pressure He/O2 plasma microjet (APPμJ was proposed. The APPμJ system combines an atmospheric pressure plasma jet (APPJ with a microfabricated silicon micronozzle with dimension of 30 μm, which has advantages of simple structure and low cost. The possibility of APPμJ in functionalizing PU films with hydroxyl (–OH groups and covalent grafting of gelatin for improving its biocompatibility was demonstrated. The morphologies and chemical compositions of the modified surface were analyzed by scanning electronic microscopy (SEM, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS. The fluorescent images show the modified surface can be divided into four areas with different fluorescence intensity from the center to the outside domain. The distribution of the rings could be controlled by plasma process parameters, such as the treatment time and the flow rate of O2. When the treatment time is 4 to 5 min with the oxygen percentage of 0.6%, the PU film can be effectively local functionalized with the diameter of 170 μm. In addition, the modification mechanism of PU films by the APPμJ is investigated. The localized polymer modified by APPμJ has potential applications in the field of tissue engineering.

  3. Immobilization of chitosan film containing semaphorin 3A onto a microarc oxidized titanium implant surface via silane reaction to improve MG63 osteogenic differentiation

    Directory of Open Access Journals (Sweden)

    Fang K

    2014-10-01

    Full Text Available Kaixiu Fang,1,* Wen Song,2,* Lifeng Wang,1 Sen Jia,3 Hongbo Wei,1 Shuai Ren,1 Xiaoru Xu,1 Yingliang Song1 1State Key Laboratory of Military Stomatology, Department of Implant Dentistry, School of Stomatology, Fourth Military Medical University, Xi’an, People’s Republic of China; 2State Key Laboratory of Military Stomatology, Department of Prosthetic Dentistry, School of Stomatology, Fourth Military Medical University, Xi’an, People’s Republic of China; 3State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi’an, People’s Republic of China *These authors contributed equally to this work Abstract: Improving osseointegration of extensively used titanium (Ti implants still remains a main theme in implantology. Recently, grafting biomolecules onto a Ti surface has attracted more attention due to their direct participation in the osseointegration process around the implant. Semaphorin 3A (Sema3A is a new proven osteoprotection molecule and is considered to be a promising therapeutic agent in bone diseases, but how to immobilize the protein onto a Ti surface to acquire a long-term effect is poorly defined. In our study, we tried to use chitosan to wrap Sema3A (CS/Sema and connect to the microarc oxidized Ti surface via silane glutaraldehyde coupling. The microarc oxidization could formulate porous topography on a Ti surface, and the covalently bonded coating was homogeneously covered on the ridges between the pores without significant influence on the original topography. A burst release of Sema3A was observed in the first few days in phosphate-buffered saline and could be maintained for >2 weeks. Coating in phosphate-buffered saline containing lysozyme was similar, but the release rate was much more rapid. The coating did not significantly affect cellular adhesion, viability, or cytoskeleton arrangement, but the osteogenic-related gene

  4. Immobilization of Chlorosulfonyl-Calix[4]arene onto the surface of silica gel through the directly estrification

    Energy Technology Data Exchange (ETDEWEB)

    Taghvaei-Ganjali, Saeed, E-mail: S-taghvaei@IAU-tnb.ac.ir [Chemistry Department, Islamic Azad University, North Tehran Branch, Postal Code: 1913674711, Tehran (Iran, Islamic Republic of); Zadmard, Reza [Chemistry and Chemical Engineering Research Center of Iran, Postal Code: 1496813151, Tehran (Iran, Islamic Republic of); Saber-Tehrani, Mandana [Chemistry Department, Islamic Azad University, North Tehran Branch, Postal Code: 1913674711, Tehran (Iran, Islamic Republic of)

    2012-06-01

    For the first time Chlorosulfonyl-Calix[4]arene has been chemically bonded to silica gel through the directly estrification without silane coupling agent to prepare Chlorosulfonyl-Calix[4]arene-bonded silica gel. Sample characterization was performed by various techniques such as elemental analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), powder X-ray diffraction (XRD), N{sub 2} adsorption-desorption, thermal gravimetric analysis (TGA), {sup 29}Si CP/MAS spectroscopy and acid-base titration. All data approve the successful incorporation of organic group via covalent bond. From the comparison between sulfur content determined by elemental analysis and the number of H{sup +} determined by acid-base titration, it was shown that two ester units took place onto the new synthesized sample and two acidic sites exist on the surface.

  5. Immobilization of Chlorosulfonyl-Calix[4]arene onto the surface of silica gel through the directly estrification

    Science.gov (United States)

    Taghvaei-Ganjali, Saeed; Zadmard, Reza; Saber-Tehrani, Mandana

    2012-06-01

    For the first time Chlorosulfonyl-Calix[4]arene has been chemically bonded to silica gel through the directly estrification without silane coupling agent to prepare Chlorosulfonyl-Calix[4]arene-bonded silica gel. Sample characterization was performed by various techniques such as elemental analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), powder X-ray diffraction (XRD), N2 adsorption-desorption, thermal gravimetric analysis (TGA), 29Si CP/MAS spectroscopy and acid-base titration. All data approve the successful incorporation of organic group via covalent bond. From the comparison between sulfur content determined by elemental analysis and the number of H+ determined by acid-base titration, it was shown that two ester units took place onto the new synthesized sample and two acidic sites exist on the surface.

  6. Surface Immobilized His-tagged Azurin as a Model Interface for the Investigation of Vectorial Electron Transfer in Biological Systems

    International Nuclear Information System (INIS)

    Casalini, Stefano; Berto, Marcello; Kovtun, Alessandro; Operamolla, Alessandra; Di Rocco, Giulia; Facci, Paolo; Liscio, Andrea; Farinola, Gianluca M.; Borsari, Marco; Bortolotti, Carlo A.

    2015-01-01

    A model system for the electrochemical investigation of vectorial electron transfer in biological systems was designed, assembled and characterized. Gold electrodes, functionalized with a -OCH_3 terminated, aromatic self-assembled monolayer, were used as a substrate for the adsorption of variants of copper-containing, redox metalloprotein azurin. The engineered azurin bears a polyhistidine tag at its C-terminus. Thanks to the presence of the solvent exposed tag, which chelates Cu"2"+ ions in solution, we introduced an exogenous redox centre. The different reduction potentials of the two redox centres and their positioning with respect to the surface are such that electron transfer from the exogenous copper centre and the electrode is mediated by the native azurin active site, closely paralleling electron transfer processes in naturally occurring multicentre metalloproteins.

  7. Antimicrobial activity of immobilized lactoferrin and lactoferricin.

    Science.gov (United States)

    Chen, Renxun; Cole, Nerida; Dutta, Debarun; Kumar, Naresh; Willcox, Mark D P

    2017-11-01

    Lactoferrin and lactoferricin were immobilized on glass surfaces via two linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The antimicrobial activity of the surfaces was determined using Pseudomonas aeruginosa and Staphylococcus aureus strains by fluorescence microscopy. Lactoferrin and lactoferricin immobilization was confirmed by XPS showing significant increases (p lactoferricin immobilized on glass significantly (p lactoferricin were successfully immobilized on glass surfaces and showed promising antimicrobial activity against pathogenic bacteria. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2612-2617, 2017. © 2016 Wiley Periodicals, Inc.

  8. Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

    Science.gov (United States)

    Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

    2015-01-01

    Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

  9. Quantitative structure-retention relationship studies using immobilized artificial membrane chromatography I: amended linear solvation energy relationships with the introduction of a molecular electronic factor.

    Science.gov (United States)

    Li, Jie; Sun, Jin; Cui, Shengmiao; He, Zhonggui

    2006-11-03

    Linear solvation energy relationships (LSERs) amended by the introduction of a molecular electronic factor were employed to establish quantitative structure-retention relationships using immobilized artificial membrane (IAM) chromatography, in particular ionizable solutes. The chromatographic indices, log k(IAM), were determined by HPLC on an IAM.PC.DD2 column for 53 structurally diverse compounds, including neutral, acidic and basic compounds. Unlike neutral compounds, the IAM chromatographic retention of ionizable compounds was affected by their molecular charge state. When the mean net charge per molecule (delta) was introduced into the amended LSER as the sixth variable, the LSER regression coefficient was significantly improved for the test set including ionizable solutes. The delta coefficients of acidic and basic compounds were quite different indicating that the molecular electronic factor had a markedly different impact on the retention of acidic and basic compounds on IAM column. Ionization of acidic compounds containing a carboxylic group tended to impair their retention on IAM, while the ionization of basic compounds did not have such a marked effect. In addition, the extra-interaction with the polar head of phospholipids might cause a certain change in the retention of basic compounds. A comparison of calculated and experimental retention indices suggested that the semi-empirical LSER amended by the addition of a molecular electronic factor was able to reproduce adequately the experimental retention factors of the structurally diverse solutes investigated.

  10. 100KE/KW fuel storage basin surface volumetric factors

    International Nuclear Information System (INIS)

    Conn, K.R.

    1996-01-01

    This Supporting Document presents calculations of surface Volumetric factors for the 100KE and 100KW Fuel Storage Basins. These factors relate water level changes to basin loss or additions of water, or the equivalent water displacement volumes of objects added to or removed from the basin

  11. Characteristics of immobilized aminoacylase from Aspergillus oryzae on macroporous copolymers.

    Science.gov (United States)

    He, B L; Jiang, P; Qiu, Y B

    1990-01-01

    Aminoacylase from Aspergillus oryzae was adsorbed on functionallized macroporous copolymers where the enzyme showed excellent catalyzing activity and operation stability. Various factors which effect the activity of the immobilized aminoacylase such as temperature, pH and ionic strength were investigated. The continuous operation of the enzyme immobilized on macroporous copolymers was compared with that of the enzyme immobilized on DEAE-Sephadex.

  12. Degradation of phenol and TCE using suspended and chitosan-bead immobilized Pseudomonas putida.

    Science.gov (United States)

    Chen, Yan-Min; Lin, Tsair-Fuh; Huang, Chih; Lin, Jui-Che; Hsieh, Feng-Ming

    2007-09-30

    The degradability of phenol and trichloroethene (TCE) by Pseudomonas putida BCRC 14349 in both suspended culture and immobilized culture systems are investigated. Chitosan beads at a size of about 1-2mm were employed to encapsulate the P. putida cells, becoming an immobilized culture system. The phenol concentration was controlled at 100 mg/L, and that of TCE was studied from 0.2 to 20 mg/L. The pH, between 6.7 and 10, did not affect the degradation of either phenol or TCE in the suspended culture system. However, it was found to be an important factor in the immobilized culture system in which the only significant degradation was observed at pH >8. This may be linked to the surface properties of the chitosan beads and its influence on the activity of the bacteria. The transfer yield of TCE on a phenol basis was almost the same for the suspended and immobilized cultures (0.032 mg TCE/mg phenol), except that these yields occurred at different TCE concentrations. The transfer yield at a higher TCE concentration for the immobilized system suggested that the cells immobilized in carriers can be protected from harsh environmental conditions. For kinetic rate interpretation, the Monod equation was employed to describe the degradation rates of phenol, while the Haldane's equation was used for TCE degradation. Based on the kinetic parameters obtained from the two equations, the rate for the immobilized culture systems was only about 1/6 to that of the suspended culture system for phenol degradation, and was about 1/2 for TCE degradation. The slower kinetics observed for the immobilized culture systems was probably due to the slow diffusion of substrate molecules into the beads. However, compared with the suspended cultures, the immobilized cultures may tolerate a higher TCE concentration as much less inhibition was observed and the transfer yield occurred at a higher TCE concentration.

  13. Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

    International Nuclear Information System (INIS)

    Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua

    2016-01-01

    Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

  14. Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua, E-mail: hrh20022002@163.com

    2016-04-30

    Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

  15. Influencing factors on the visibility of surface distresses

    Science.gov (United States)

    Smęt, Wojciech; Skakuj, Marek

    2018-05-01

    A systematic and future-oriented maintenance management requires quality-assured data regarding the condition of the roadway. An important characteristic for assessing the condition of the road surface are cracks [1]. Experience has proven that the road surface temperature and residual humidity can influence the visibility of cracks. To investigate and quantify these influencing factors in more detail, the Federal Ministry of Transport and Digital Infrastructure has implemented a comprehensive research project [2], during which several measurement campaigns were carried out at different seasons and at different temperatures and humidity degrees of the road surface. The visibility of the cracks was assessed using the German approach ZTV ZEB-StB [3]. After evaluating the cracks, the data was synchronized and the network allocation of the geo-referenced raw data was realized. The relevant condition performance indicators were calculated subsequently. For each evaluation section of 100 meters length, the mean road surface temperature was calculated and, if available, the type and year of construction of the surface course was determined. The evaluated data was visualized to establish correlations between the data and the influencing factors. For the statistical analysis of the results, a total of six comparative scenarios were defined in which the influencing factors of road surface temperature and residual humidity were assessed. This paper documents the results of the research project. In order to obtain a uniform and comparable picture of the condition of the road surface over the years and thus to be able to observe the aging process of the road surface, the measurement campaigns are to be carried out under defined conditions. The research project included proposals for defining and further specifying the measurement conditions.

  16. Upregulation of interleukin-1β/transforming growth factor-β1 and hypoxia relate to molecular mechanisms underlying immobilization-induced muscle contracture.

    Science.gov (United States)

    Honda, Yuichiro; Sakamoto, Junya; Nakano, Jiro; Kataoka, Hideki; Sasabe, Ryo; Goto, Kyo; Tanaka, Miho; Origuchi, Tomoki; Yoshimura, Toshiro; Okita, Minoru

    2015-09-01

    In this study we investigated the molecular mechanism underlying muscle contracture in rats. The rats were divided into immobilization and control groups, and soleus muscles of the right and left sides were selected for analyses. The levels of CD11b and α-SMA protein, IL-1β, and TGF-β1 mRNA, and type I and III collagen protein and mRNA were significantly greater in the immobilization group than in the control group at all time-points. HIF-1α mRNA levels were significantly higher in the immobilization group at 4 weeks. Moreover, HIF-1α, α-SMA, and type I collagen levels were significantly higher at 4 weeks than at 1 and 2 weeks in the immobilization group. In the early stages of immobilization, upregulation of IL-1β/TGF-β1 via macrophages may promote fibroblast differentiation that could affect muscle contracture. The soleus muscle became hypoxic in the later stages of immobilization, suggesting that hypoxia influences the progression of muscle contracture. © 2014 Wiley Periodicals, Inc.

  17. Immobilized enzymes and cells

    Energy Technology Data Exchange (ETDEWEB)

    Bucke, C; Wiseman, A

    1981-04-04

    This article reviews the current state of the art of enzyme and cell immobilization and suggests advances which might be made during the 1980's. Current uses of immobilized enzymes include the use of glucoamylase in the production of glucose syrups from starch and glucose isomerase in the production of high fructose corn syrup. Possibilities for future uses of immobilized enzymes and cells include the utilization of whey and the production of ethanol.

  18. Application of magnetic nanoparticles in smart enzyme immobilization.

    Science.gov (United States)

    Vaghari, Hamideh; Jafarizadeh-Malmiri, Hoda; Mohammadlou, Mojgan; Berenjian, Aydin; Anarjan, Navideh; Jafari, Nahideh; Nasiri, Shahin

    2016-02-01

    Immobilization of enzymes enhances their properties for efficient utilization in industrial processes. Magnetic nanoparticles, due to their high surface area, large surface-to-volume ratio and easy separation under external magnetic fields, are highly valued. Significant progress has been made to develop new catalytic systems that are immobilized onto magnetic nanocarriers. This review provides an overview of recent developments in enzyme immobilization and stabilization protocols using this technology. The current applications of immobilized enzymes based on magnetic nanoparticles are summarized and future growth prospects are discussed. Recommendations are also given for areas of future research.

  19. Anti-inflammatory and antioxidant effect of cerium dioxide nanoparticles immobilized on the surface of silica nanoparticles in rat experimental pneumonia.

    Science.gov (United States)

    Serebrovska, Z; Swanson, R J; Portnichenko, V; Shysh, A; Pavlovich, S; Tumanovska, L; Dorovskych, A; Lysenko, V; Tertykh, V; Bolbukh, Y; Dosenko, V

    2017-08-01

    A massage with the potent counter-inflammatory material, cerium dioxide nanoparticles, is promising and the antioxidant properties of CeO 2 are considered the main, if not the only, mechanism of this action. Nevertheless, the elimination of ceria nano-particles from the organism is very slow and there is a strong concern for toxic effect of ceria due to its accumulation. To overcome this problem, we engineered a combined material in which cerium nanoparticles were immobilized on the surface of silica nanoparticles (CeO 2 NP), which is shown to be easily removed from an organism and could be used as carriers for nano-ceria. In our study particle size was 220±5nm, Zeta-potential -4.5mV (in water), surface charge density -17.22μC/cm 2 (at pH 7). Thirty-six male Wistar rats, 5 months old and 250-290g were divided into four groups: 1) control; 2) CeO 2 NP treatment; 3) experimental pneumonia (i/p LPS injection, 1mg/kg); and 4) experimental pneumonia treated with CeO 2 NP (4 times during the study in dosage of 0.6mg/kg with an orogastric catheter). Gas exchange and pulmonary ventilation were measured four times: 0, 1, 3 and 24h after LPS injection in both untreated and CeO 2 NP-treated animals. The mRNA of TNF-α, Il-6, and CxCL2 were determined by RT-PCR. ROS-generation in blood plasma and lung tissue homogenates were measured by means of lucigenin- and luminol-enhanced chemiluminescence. Endotoxemia in the acute phase was associated with: (1) pathological changes in lung morphology; (2) increase of ROS generation; (3) enhanced expression of CxCL2; and (4) a gradual decrease of VO 2 and V E . CeO2 NP treatment of intact animals did not make any changes in all studied parameters except for a significant augmentation of VO 2 and V E. CeO 2 NP treatment of rats with pneumonia created positive changes in diminishing lung tissue injury, decreasing ROS generation in blood and lung tissue and decreasing pro-inflammatory cytokine expression (TNF-α, Il-6 and CxCL2). Oxygen

  20. An inexpensive and simple method for thermally stable immobilization of DNA on an unmodified glass surface: UV linking of poly(T)10-poly(C)10-tagged DNA probes

    DEFF Research Database (Denmark)

    Guðnason, Haukur; Dufva, Hans Martin; Bang, Dang Duong

    2008-01-01

    be linked by UV light irradiation onto a plain, unmodified glass surface. Probes immobilized onto unmodified glass microscope slides performed similarly to probes bound to commercial amino-silane-coated slides and had comparable detection limits. The TC-tagged probes linked to unmodified glass did not show...... any significant decrease in hybridization performance after a 20 min incubation in water at 100 degrees C prior to rehybridization, indicating a covalent bond between the TC tag and unmodified glass. The probes were used in thermal minisequencing cycling reactions. Furthermore, the TC tag improved...

  1. Topography measurements for determining the decay factors in surface replication

    International Nuclear Information System (INIS)

    Song, J; Zheng, A; Vorburger, T V; Rubert, P

    2008-01-01

    The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

  2. Immobilized waste leaching

    International Nuclear Information System (INIS)

    Suarez, A.A.

    1989-01-01

    The main mechanism by which the immobilized radioactive materials can return to biosphere is the leaching due to the intrusion of water into the repositories. Some mathematical models and experiments utilized to evaluate the leaching rates in different immobilization matrices are described. (author) [pt

  3. Protic ionic liquid as additive on lipase immobilization using silica sol-gel.

    Science.gov (United States)

    de Souza, Ranyere Lucena; de Faria, Emanuelle Lima Pache; Figueiredo, Renan Tavares; Freitas, Lisiane dos Santos; Iglesias, Miguel; Mattedi, Silvana; Zanin, Gisella Maria; dos Santos, Onélia Aparecida Andreo; Coutinho, João A P; Lima, Álvaro Silva; Soares, Cleide Mara Faria

    2013-03-05

    Ionic liquids (ILs) have evolved as a new type of non-aqueous solvents for biocatalysis, mainly due to their unique and tunable physical properties. A number of recent review papers have described a variety of enzymatic reactions conducted in IL solutions, on the other hand, to improve the enzyme's activity and stability in ILs; major methods being explored include the enzyme immobilization (on solid support, sol-gel, etc.), protic ionic liquids used as an additive process. The immobilization of the lipase from Burkholderia cepacia by the sol-gel technique using protic ionic liquids (PIL) as additives to protect against inactivation of the lipase due to release of alcohol and shrinkage of the gel during the sol-gel process was investigated in this study. The influence of various factors such as the length of the alkyl chain of protic ionic liquids (monoethanolamine-based) and a concentration range between 0.5 and 3.0% (w/v) were evaluated. The resulting hydrophobic matrices and immobilized lipases were characterised with regard to specific surface area, adsorption-desorption isotherms, pore volume (V(p)) and size (d(p)) according to nitrogen adsorption and scanning electron microscopy (SEM), physico-chemical properties (thermogravimetric - TG, differential scanning calorimetry - DSC and Fourier transform infrared spectroscopy - FTIR) and the potential for ethyl ester and emulsifier production. The total activity yields (Y(a)) for matrices of immobilized lipase employing protic ionic liquids as additives always resulted in higher values compared with the sample absent the protic ionic liquids, which represents 35-fold increase in recovery of enzymatic activity using the more hydrophobic protic ionic liquids. Compared with arrays of the immobilized biocatalyst without additive, in general, the immobilized biocatalyst in the presence of protic ionic liquids showed increased values of surface area (143-245 m(2) g(-1)) and pore size (19-38 Å). Immobilization with

  4. [Differential Effect and Mechanism of in situ Immobilization of Cadmium Contamination in Soil Using Diatomite Produced from Different Areas].

    Science.gov (United States)

    Zhu, Jian; Wang, Ping; Lin, Yan; Lei, Ming-jing; Chen, Yang

    2016-02-15

    In order to understand the difference of in situ immobilization effect and mechanism of Cd contamination in soil using diatomite produced from different areas, the test was conducted using diatomite produced from Yunnan Tengchong, Jilin Linjiang, Zhejiang Shengzhou and Henan Xinyang of China as modifiers to immobilize cadmium contamination in simulated soil. The results indicated that the diatomite from all the four producing areas could effectively immobilize available Cd in soil, decreasing the available Cd content in soil by 27.7%, 28.5%, 30.1% and 57.2%, respectively when the adding concentration was 30 g x kg(-1). Their ability for immobilizing available Cd in soil followed the sequence of Henan Xinyang > Zhejiang Shengzhou > Jilin Linjiang > Yunnan Tengchong. It was also found that the physical and chemical properties of diatomite played a main role in soil cadmium immobilization, lower bulk density, larger specific surface area, more micro pores and wider distribution range of aperture were more favorable for available Cd immobilization. The results also showed that, the diatomite could control Cd contamination by changing soil physical and chemical properties, among these properties, pH and organic matter content were the key factors, increasing soil pH value and organic matter content was favorable for available cadmium immobilization, while the soil water content had little effect on available cadmium immobilization. The control of soil cadmium contamination by using diatomite to change cation exchange capacity was limited by time in some degree. The diatomite produced from Henan Xinyang, Zhejiang Shengzhou and Yunnan Tengchong increased the soil pH value and organic matter content, and was favorable for available Cd immobilization, while the diatomite from Jilin Linjiang showed converse effect.

  5. Immobilization of inorganic pyrophosphatase on nanodiamond particles retaining its high enzymatic activity.

    Science.gov (United States)

    Rodina, Elena V; Valueva, Anastasiya V; Yakovlev, Ruslan Yu; Vorobyeva, Nataliya N; Kulakova, Inna I; Lisichkin, Georgy V; Leonidov, Nikolay B

    2015-12-21

    Nanodiamond (ND) particles are popular platforms for the immobilization of molecular species. In the present research, enzyme Escherichia coli inorganic pyrophosphatase (PPase) was immobilized on detonation ND through covalent or noncovalent bonding and its enzymatic activity was characterized. Factors affecting adsorption of PPase such as ND size and surface chemistry were studied. The obtained material is a submicron size association of ND particles and protein molecules in approximately equal amounts. Both covalently and noncovalently immobilized PPase retains a significant enzymatic activity (up to 95% of its soluble form) as well as thermostability. The obtained hybrid material has a very high enzyme loading capacity (∼1 mg mg(-1)) and may be considered as a promising delivery system of biologically active proteinaceous substances, particularly in the treatment of diseases such as calcium pyrophosphate crystal deposition disease and related pathologies. They can also be used as recoverable heterogeneous catalysts in the traditional uses of PPase.

  6. Plutonium Disposition by Immobilization

    International Nuclear Information System (INIS)

    Gould, T.; DiSabatino, A.; Mitchell, M.

    2000-01-01

    The ultimate goal of the Department of Energy (DOE) Immobilization Project is to develop, construct, and operate facilities that will immobilize between 17 to 50 tonnes (MT) of U.S. surplus weapons-usable plutonium materials in waste forms that meet the ''spent fuel'' standard and are acceptable for disposal in a geologic repository. Using the ceramic can-in-canister technology selected for immobilization, surplus plutonium materials will be chemically combined into ceramic forms which will be encapsulated within large canisters of high level waste (HLW) glass. Deployment of the immobilization capability should occur by 2008 and be completed within 10 years. In support of this goal, the DOE Office of Fissile Materials Disposition (MD) is conducting development and testing (D and T) activities at four DOE laboratories under the technical leadership of Lawrence Livermore National Laboratory (LLNL). The Savannah River Site has been selected as the site for the planned Plutonium Immobilization Plant (PIP). The D and T effort, now in its third year, will establish the technical bases for the design, construction, and operation of the U. S. capability to immobilize surplus plutonium in a suitable and cost-effective manner. Based on the D and T effort and on the development of a conceptual design of the PIP, automation is expected to play a key role in the design and operation of the Immobilization Plant. Automation and remote handling are needed to achieve required dose reduction and to enhance operational efficiency

  7. Heterogeneous electron transfer of a two-centered heme protein: redox and electrocatalytic properties of surface-immobilized cytochrome C(4).

    Science.gov (United States)

    Monari, Stefano; Battistuzzi, Gianantonio; Borsari, Marco; Di Rocco, Giulia; Martini, Laura; Ranieri, Antonio; Sola, Marco

    2009-10-15

    The recombinant diheme cytochrome c(4) from the psycrophilic bacterium Pseudoalteromonas haloplanktis TAC 125 and its Met64Ala and Met164Ala variants, which feature a hydroxide ion axially bound to the heme iron at the N- and C-terminal domains, respectively, were found to exchange electrons efficiently with a gold electrode coated with a SAM of 11-mercapto-1-undecanoic acid. The mutation-induced removal of the redox equivalence of the two heme groups and changes in the net charge of the protein lobes yield two-centered protein systems with unprecedented properties in the electrode-immobilized state. The heterogeneous and intraheme electron transfer processes were characterized for these species in which the high- and low-potential heme groups are swapped over in the bilobal protein framework and experience a constrained (M64A) and unconstrained (M164A) orientation toward the electrode. The reduction thermodynamics for the native and mutated hemes were measured for the first time for a diheme cytochrome c. In the diffusing regime, they reproduce closely those for the corresponding centers in single-heme class-I cytochromes c, despite the low sequence identity. Larger differences are observed in the thermodynamics of the immobilized species and in the heterogeneous electron transfer rate constants. T-dependent kinetic measurements show that the proteins are positioned approximately 7 A from the HOOC-terminated SAM-coated electrode. Protein-electrode orientation and efficient intraheme ET enable the His,OH(-)-ligated heme A of the immobilized Met64Ala variant to carry out the reductive electrocatalysis of molecular oxygen. This system therefore constitutes a novel two-centered heme-based biocatalytic interface to be exploited for "third-generation" amperometric biosensing.

  8. Colony to colorimetry in 6 h: ELISA detection of a surface-expressed Pseudomonas aeruginosa virulence factor using immobilized bacteria.

    Science.gov (United States)

    Adawi, Azmi; Neville, Lewis F

    2012-09-01

    A rapid ELISA employing intact Pseudomonas aeruginosa (PA) is described that allows discrimination between strains harboring flagellin type a or b. All 52 PA strains known to harbor flagellin type b were positive in this ELISA when screened with a fully human monoclonal antibody (LST-007) targeting flagellin type b. Completion of this assay in only 6 h, from picking a single bacterial colony to a colorimetric product, could easily be adapted to a clinical laboratory setting and permit the appropriate choice of therapeutic monoclonal antibody versus its homologous flagellin target in PA-infected patients. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. A disposal centre for immobilized nuclear waste

    International Nuclear Information System (INIS)

    1980-02-01

    This report describes a conceptual design of a disposal centre for immobilized nuclear waste. The surface facilities consist of plants for the preparation of steel cylinders containing nuclear waste immobilized in glass, shaft headframe buildings and all necessary support facilities. The underground disposal vault is located on one level at a depth of 1000 m. The waste cylinders are emplaced into boreholes in the tunnel floors. All surface and subsurface facilities are described, operations and schedules are summarized, and cost estimates and manpower requirements are given. (auth)

  10. Calculation of Operations Efficiency Factors for Mars Surface Missions

    Science.gov (United States)

    Layback, Sharon L.

    2014-01-01

    For planning of Mars surface missions, to be operated on a sol-by-sol basis by a team on Earth (where a "sol" is a Martian day), activities are described in terms of "sol types" that are strung together to build a surface mission scenario. Some sol types require ground decisions based on a previous sol's results to feed into the activity planning ("ground in the loop"), while others do not. Due to the differences in duration between Earth days and Mars sols, for a given Mars local solar time, the corresponding Earth time "walks" relative to the corresponding times on the prior sol/day. In particular, even if a communication window has a fixed Mars local solar time, the Earth time for that window will be approximately 40 minutes later each succeeding day. Further complexity is added for non-Mars synchronous communication relay assets, and when there are multiple control centers in different Earth time zones. The solution is the development of "ops efficiency factors" that reflect the efficiency of a given operations configuration (how many and location of control centers, types of communication windows, synchronous or non-synchronous nature of relay assets, sol types, more-or-less sustainable operations schedule choices) against a theoretical "optimal" operations configuration for the mission being studied. These factors are then incorporated into scenario models in order to determine the surface duration (and therefore minimum spacecraft surface lifetime) required to fulfill scenario objectives. The resulting model is used to perform "what-if" analyses for variations in scenario objectives. The ops efficiency factor is the ratio of the figure of merit for a given operations factor to the figure of merit for the theoretical optimal configuration. The current implementation is a pair of models in Excel. The first represents a ground operations schedule for 500 sols in each operations configuration for the mission being studied (500 sols was chosen as being a long

  11. A simple method for quantification of interferon-α2b through surface ...

    African Journals Online (AJOL)

    USER

    2010-03-15

    Mar 15, 2010 ... through surface plasmon resonance technique. Ramakrishnan ... active protein and it is one of the growth factor that ... protein binding (Stenberg et al., 1991). SPR ... immobilization due to the electrostatic attraction between.

  12. Electrochemical properties of the hexacyanoferrate(II)–ruthenium(III) complex immobilized on silica gel surface chemically modified with zirconium(IV) oxide

    International Nuclear Information System (INIS)

    Panice, Lucimara B.; Oliveira, Elisangela A. de; Filho, Ricardo A.D. Molin; Oliveira, Daniela P. de; Lazarin, Angélica M.; Andreotti, Elza I.S.; Sernaglia, Rosana L.; Gushikem, Yoshitaka

    2014-01-01

    Highlights: • The cyano-bridged mixed valence ruthenium composite material was synthesized. • This newly synthesized compound was incorporated into a carbon paste electrode. • The electrode did not show significant changes in response after six months of use. • The modified electrode is very stable and reproducible. • The electrode sensor was successfully applied for ascorbic acid determination. - Abstract: The chemically modified silica gel with zirconium(IV) oxide was used to immobilize the [Fe(CN) 6 ] 4− complex ion initially. The reaction of this material with [Ru(edta)H 2 O] − complex ion formed the immobilized cyano-bridged mixed valence ruthenium complex, (≡Zr) 5 [(edta)RuNCFe(CN) 5 ]. This material was incorporated into a carbon paste electrode and, its electrochemical properties were investigated. However, for an ascorbic acid solution, an enhancement of the anodic peak current was detected due to electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for ascorbic acid determination in pharmaceutical preparation with success

  13. Preparation of immobilized growing cells and enzymatic hydrolysis of sawdust

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1984-01-01

    Trichoderma reesei cells were immobilized by radiation polymerization using porous materials such as non-woven material and sawdust, and the enzymatic hydrolysis of sawdust with the enzyme solution from the immobilized growing cells was studied. The filter paper activity, which shows the magnitude of cellulase production in the immobilized cells, was comparable with that in the intact cells. The filter paper activity was affected by addition concentration of monomer and porous materials. The cells in the immobilized cells grew to be adhered on the surface of the fibrous polymers. Sawdust, which was pretreated by irradiation technique, was effectively hydrolyzed with the enzyme solution resulting from the culture of the immobilized cells, in which the glucose yield increased increasing the culture time of the immobilized cells. (author)

  14. Calculation of Operations Efficiency Factors for Mars Surface Missions

    Science.gov (United States)

    Laubach, Sharon

    2014-01-01

    The duration of a mission--and subsequently, the minimum spacecraft lifetime--is a key component in designing the capabilities of a spacecraft during mission formulation. However, determining the duration is not simply a function of how long it will take the spacecraft to execute the activities needed to achieve mission objectives. Instead, the effects of the interaction between the spacecraft and ground operators must also be taken into account. This paper describes a method, using "operations efficiency factors", to account for these effects for Mars surface missions. Typically, this level of analysis has not been performed until much later in the mission development cycle, and has not been able to influence mission or spacecraft design. Further, the notion of moving to sustainable operations during Prime Mission--and the effect that change would have on operations productivity and mission objective choices--has not been encountered until the most recent rover missions (MSL, the (now-cancelled) joint NASA-ESA 2018 Mars rover, and the proposed rover for Mars 2020). Since MSL had a single control center and sun-synchronous relay assets (like MER), estimates of productivity derived from MER prime and extended missions were used. However, Mars 2018's anticipated complexity (there would have been control centers in California and Italy, and a non-sun-synchronous relay asset) required the development of an explicit model of operations efficiency that could handle these complexities. In the case of the proposed Mars 2018 mission, the model was employed to assess the mission return of competing operations concepts, and as an input to component lifetime requirements. In this paper we provide examples of how to calculate the operations efficiency factor for a given operational configuration, and how to apply the factors to surface mission scenarios. This model can be applied to future missions to enable early effective trades between operations design, science mission

  15. Immobilizing Biomolecules Near the Diffraction Limit

    DEFF Research Database (Denmark)

    Skovsen, Esben; Petersen, Maria Teresa Neves; Gennaro, Ane Kold Di

    2009-01-01

    Our group has previously shown that biomolecules containing disulfide bridges in close proximity to aromatic residues can be immobilized, through covalent bonds, onto thiol derivatized surfaces upon UV excitation of the aromatic residue(s). We have also previously shown that our new technology ca...

  16. Immobilization of Trichoderma reesei by radiation polymerization

    International Nuclear Information System (INIS)

    Zhou Ruimin; Ma Zueteh; Kaetus, Isao; Kumakura, Minoro

    1993-01-01

    Immobilization of Trichoderma reesei was carried out by radiation polymerization. It was found that the activity of fixed cells increased with increasing surface area of the carrier and was affected by the concentration of monomer tetraethylenglycol dimethacrylate and the shape of the substrate composition and structure of cotton textile fabrics. (author)

  17. Isomaltulose production using free and immobilized Serratia ...

    African Journals Online (AJOL)

    Isomaltulose is a low cariogenic sweetener used as a substitute for sucrose in the food industry. In this study, isomaltulose production by Serratia plymuthica ATCC 15928 was performed using free and immobilized cells. Response Surface Methodology was employed to evaluate the influence of temperature, wet cell mass ...

  18. Management of immobilization and its complication for elderly.

    Science.gov (United States)

    Laksmi, Purwita W; Harimurti, Kuntjoro; Setiati, Siti; Soejono, Czeresna H; Aries, Wanarani; Roosheroe, Arya Govinda

    2008-10-01

    Increased life expectancy have an effect on the rising percentage of elderly population in Indonesia and health problem associated with the elderly, particularly immobilization. Immobilization may cause various complications, especially when it has been overlooked without any appropriate and proper medical care in keeping with the procedures. High incidence of immobilization in elderly and the life-threatening complication call for an agreement on management of immobilization and its complication. Management of immobilization needs interdisciplinary team-work cooperation, the patients and their family. The management may be commenced through a complete geriatric review, formulating functional goals and constructing therapeutic plan. Various medical conditions and external factors that may act as risk factors of immobilization as well as drugs intake that may exaggerate the immobilization should be evaluated and optimally managed. Any complication due to immobilization and other concomitant disease/condition should be recognized and managed comprehensively in order to reduce morbidity and mortality. Management of immobilization and its complications include pharmacological and non-pharmacological treatment, i.e. various mobility exercises, utilization of ambulatory device and supporting appliance for assisting patients in stand-up position, as well as the management of urinary voiding and defecation.

  19. Increase in stability of cellulase immobilized on functionalized magnetic nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenjuan [Department of Machine Intelligence and Systems Engineering, Faculty of Systems Engineering, Akita Prefectural University, Akita 015-0055 (Japan); Qiu, Jianhui, E-mail: qiu@akita-pu.ac.jp [Department of Machine Intelligence and Systems Engineering, Faculty of Systems Engineering, Akita Prefectural University, Akita 015-0055 (Japan); Feng, Huixia [College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Zang, Limin; Sakai, Eiichi [Department of Machine Intelligence and Systems Engineering, Faculty of Systems Engineering, Akita Prefectural University, Akita 015-0055 (Japan)

    2015-02-01

    Functionalized magnetic nanospheres were prepared by co-condensation of tetraethylorthosilicate with three different amino-silanes: 3-(2-aminoethylamino propyl)-triethoxysilane (AEAPTES), 3-(2-aminoethylamino propyl)-trimethoxysilane (AEAPTMES) and 3-aminopropyltriethoxysilane (APTES). Then three functionalized magnetic nanospheres were used as supports for immobilization of cellulase. The three functionalized magnetic nanospheres with core–shell morphologies exhibited higher capacity for cellulase immobilization than unfunctionalized magnetic nanospheres. The increasing of surface charge of functionalized magnetic nanospheres leads to an enhancement of the capacity of cellulase immobilization. Particularly, AEAPTMES with methoxy groups was favored to be hydrolyzed and grafted on unfunctionalized magnetic nanospheres than the others. AEAPTMES functionalized magnetic nanospheres with the highest zeta potential (29 mV) exhibited 87% activity recovery and the maximum amount of immobilized cellulase was 112 mg/g support at concentration of initial cellulase of 8 mg/mL. Immobilized cellulase on AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than other immobilized cellulases and free cellulase. In particular, it can be used in about 40 °C, demonstrating the potential of biofuel production using this immobilized cellulase. - Highlights: • Three Amino-silane modified magnetic nanospheres were prepared. • Cellulase immobilized AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than free cellulase. • The potential of biofuel production using this immobilized cellulase.

  20. Increase in stability of cellulase immobilized on functionalized magnetic nanospheres

    International Nuclear Information System (INIS)

    Zhang, Wenjuan; Qiu, Jianhui; Feng, Huixia; Zang, Limin; Sakai, Eiichi

    2015-01-01

    Functionalized magnetic nanospheres were prepared by co-condensation of tetraethylorthosilicate with three different amino-silanes: 3-(2-aminoethylamino propyl)-triethoxysilane (AEAPTES), 3-(2-aminoethylamino propyl)-trimethoxysilane (AEAPTMES) and 3-aminopropyltriethoxysilane (APTES). Then three functionalized magnetic nanospheres were used as supports for immobilization of cellulase. The three functionalized magnetic nanospheres with core–shell morphologies exhibited higher capacity for cellulase immobilization than unfunctionalized magnetic nanospheres. The increasing of surface charge of functionalized magnetic nanospheres leads to an enhancement of the capacity of cellulase immobilization. Particularly, AEAPTMES with methoxy groups was favored to be hydrolyzed and grafted on unfunctionalized magnetic nanospheres than the others. AEAPTMES functionalized magnetic nanospheres with the highest zeta potential (29 mV) exhibited 87% activity recovery and the maximum amount of immobilized cellulase was 112 mg/g support at concentration of initial cellulase of 8 mg/mL. Immobilized cellulase on AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than other immobilized cellulases and free cellulase. In particular, it can be used in about 40 °C, demonstrating the potential of biofuel production using this immobilized cellulase. - Highlights: • Three Amino-silane modified magnetic nanospheres were prepared. • Cellulase immobilized AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than free cellulase. • The potential of biofuel production using this immobilized cellulase

  1. Enzyme production in immobilized Trichoderma reesei cells with hydrophobic polymers prepared by radiation polymerization method

    International Nuclear Information System (INIS)

    Luzhao Xin; Kumakura, Minoru; Kaetsu, Isao

    1993-01-01

    Trichoderma reesei cells were immobilized on paper covered with hydrophobic monomer, trimethylpropane triacrylate by radiation polymerization. The effect of immobilization condition on enzyme productivity was studied by measuring filter paper and cellobiose activity. The cells were adhered and grew on the surface of the carrier with the polymer giving high enzyme productivity in the immobilized cells in comparison with the free cells. Optimum concentration and volume of the coating monomer for the preparation of the immobilized cells were obtained. (author)

  2. A simple and robust approach to immobilization of antibody fragments.

    Science.gov (United States)

    Ikonomova, Svetlana P; He, Ziming; Karlsson, Amy J

    2016-08-01

    Antibody fragments, such as the single-chain variable fragment (scFv), have much potential in research and diagnostics because of their antigen-binding ability similar to a full-sized antibody and their ease of production in microorganisms. Some applications of antibody fragments require immobilization on a surface, and we have established a simple immobilization method that is based on the biotin-streptavidin interaction and does not require a separate purification step. We genetically fused two biotinylation tags-the biotin carboxyl carrier protein (BCCP) or the AviTag minimal sequence-to six different scFvs (scFv13R4, scFvD10, scFv26-10, scFv3, scFv5, and scFv12) for site-specific biotinylation in vivo by endogenous biotin ligases produced by Escherichia coli. The biotinylated scFvs were immobilized onto streptavidin-coated plates directly from cell lysates, and immobilization was detected through enzyme-linked immunosorbent assays. All scFvs fusions were successfully immobilized, and scFvs biotinylated via the BCCP tag tended to immobilize better than those biotinylated via the AviTag, even when biotinylation efficiency was improved with the biotin ligase BirA. The ability of immobilized scFvs to bind antigens was confirmed using scFv13R4 and scFvD10 with their respective targets β-galactosidase and bacteriophage lambda head protein D (gpD). The immobilized scFv13R4 bound to β-galactosidase at the same level for both biotinylation tags when the surface was saturated with the scFv, and immobilized scFvs retained their functionality for at least 100days after immobilization. The simplicity and robustness of our method make it a promising approach for future applications that require antibody fragment immobilization. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Covalent immobilization of invertase on PAMAM-dendrimer modified superparamagnetic iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Uzun, K.; Cevik, E.; Senel, M.; Soezeri, H.; Baykal, A.; Abasiyanik, M. F.; Toprak, M. S.

    2010-01-01

    In this study, polyamidoamine (PAMAM) dendrimer was synthesized on the surface of superparamagnetite nanoparticles to enhance invertase immobilization. The amount of immobilized enzyme on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times (i.e., 250%) as much as that of magnetite nanoparticle modified with only amino silane. Maximum reaction rate (V max ) and Michaelis-Menten constant (K m ) were determined for the free and immobilized enzymes. Various characteristics of immobilized invertase such as; the temperature activity, thermal stability, operational stability, and storage stability were evaluated and results revealed that stability of the enzyme is improved upon immobilization.

  4. Haloalkane hydrolysis with an immobilized haloalkane dehalogenase.

    Science.gov (United States)

    Dravis, B C; Swanson, P E; Russell, A J

    2001-11-20

    Haloalkane dehalogenase from Rhodococcus rhodochrous was covalently immobilized onto a polyethyleneimine impregnated gamma-alumina support. The dehalogenating enzyme was found to retain greater than 40% of its original activity after immobilization, displaying an optimal loading (max. activity/supported protein) of 70 to 75 mg/g with an apparent maximum (max. protein/support) of 156 mg/g. The substrate, 1,2,3-trichloropropane, was found to favorably partition (adsorb) onto the inorganic alumina carrier (10 to 20 mg/g), thereby increasing the local reactant concentration with respect to the catalyst's environment, whereas the product, 2,3-dichloropropan-1-ol, demonstrated no affinity. Additionally, the inorganic alumina support exhibited no adverse effects because of solvent/component incompatibilities or deterioration due to pH variance (pH 7.0 to 10.5). As a result of the large surface area to volume ratio of the support matrix and the accessibility of the bound protein, the immobilized biocatalyst was not subject to internal mass transfer limitations. External diffusional restrictions could be eliminated with simple agitation (mixing speed: 50 rpm; flux: 4.22 cm/min). The pH-dependence of the immobilized dehalogenase was essentially the same as that for the native enzyme. Finally, both the thermostability and resistance toward inactivation by organic solvent were improved by more than an order of magnitude after immobilization. Copyright 2001 John Wiley & Sons, Inc.

  5. Highly sensitive optical sensor that detects Hg"2"+ and Cu"2"+ by immobilizing dicarboxylate 1,5-diphenyl-3-thiocarbazone on surface functionalized PVA microspheres

    International Nuclear Information System (INIS)

    Bai, Xue; Gu, Haixin; Hua, Zulin; Dai, Zhangyan; Yang, Bei; Li, Yulong

    2015-01-01

    Highlights: • PVA microspheres were chosen as carrier and DDT groups were chosen as chromophores. • The DDT–PVA microspheres could detect Hg"2"+ and Cu"2"+ simultaneously within 120 s. • The DDT–PVA microspheres had excellent detection for Hg"2"+ and Cu"2"+ ions. • The DDT–PVA microspheres had preeminent selectivity and reusability. - Abstract: A novel optical sensor to detect Hg"2"+ and Cu"2"+ is prepared by immobilizing a synthesized dicarboxylate 1,5-diphenyl-3-thiocarbazone (DDT) group on functionalized polyvinyl alcohol (PVA) microspheres. This optical sensor is successfully fabricated by extensive characterization with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Its colorimetric properties, selectivity, sensitivity, and reversibility are investigated as well. In this sensing system, DDT–PVA selectively recognized multiple heavy metal ions, as indicated by the changes in color from orange to scarlet for Hg"2"+ and from orange to gray for Cu"2"+. In particular, this optical sensor exhibits the most apparent color changes at pH levels of 12 and 2. Hence, Hg"2"+ and Cu"2"+ can be detected in aqueous solution at minimum detection limits of 0.053 and 0.132 μM, respectively, with a UV-vis spectrometer. Furthermore, the sensor can be regenerated by ethylene diamine tetraacetic acid and reused several times. Therefore, the optical sensor can detect Hg"2"+ because of its selectivity, sensitivity, and reversibility.

  6. Immobilization of microorganisms. Part 1. Preparation of immobilized Lactobacillus bulgaricus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K H

    1981-01-01

    The immobilization of Lactobacillus bulgaricus on polyacrylamide and on alginate beads was investigated. The most active immobilized cells were obtained by entrapment in Ca alginate beads. These immobilized microbial cells, when introduced into 4.5% lactose solution and whey solution showed maximum relative activity of 28% for lactose and 18% for whey compared to free cells.

  7. Optimization of Immobilization of Nanodiamonds on Graphene

    International Nuclear Information System (INIS)

    Pille, A; Lange, S; Utt, K; Eltermann, M

    2015-01-01

    We report using simple dip-coating method to cover the surface of graphene with nanodiamonds for future optical detection of defects on graphene. Most important part of the immobilization process is the pre-functionalization of both, nanodiamond and graphene surfaces to obtain the selectiveness of the method. This work focuses on an example of using electrostatic attraction to confine nanodiamonds to graphene. Raman spectroscopy, microluminescence imaging and scanning electron microscopy were applied to characterize obtained samples. (paper)

  8. Limb immobilization and corticobasal syndrome.

    Science.gov (United States)

    Graff-Radford, Jonathan; Boeve, Bradley F; Drubach, Daniel A; Knopman, David S; Ahlskog, J Eric; Golden, Erin C; Drubach, Dina I; Petersen, Ronald C; Josephs, Keith A

    2012-12-01

    Recently, we evaluated two patients with corticobasal syndrome (CBS) who reported symptom onset after limb immobilization. Our objective was to investigate the association between trauma, immobilization and CBS. The charts of forty-four consecutive CBS patients seen in the Mayo Clinic Alzheimer Disease Research Center were reviewed with attention to trauma and limb immobilization. 10 CBS patients (23%) had immobilization or trauma on the most affected limb preceding the onset or acceleration of symptoms. The median age at onset was 61. Six patients manifested their first symptoms after immobilization from surgery or fracture with one after leg trauma. Four patients had pre-existing symptoms of limb dysfunction but significantly worsened after immobilization or surgery. 23 percent of patients had immobilization or trauma of the affected limb. This might have implications for management of CBS, for avoiding injury, limiting immobilization and increasing movement in the affected limb. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Laser-assisted immobilization of colloid silver nanoparticles on polyethyleneterephthalate

    Science.gov (United States)

    Siegel, Jakub; Lyutakov, Oleksiy; Polívková, Markéta; Staszek, Marek; Hubáček, Tomáš; Švorčík, Václav

    2017-10-01

    Immobilization of nanoobjects on the surface of underlying material belongs to current issues of material science. Such altered materials exhibits completely exceptional properties exploitable in a broad spectrum of industrially important applications ranging from catalysts up to health-care industry. Here we present unique approach for immobilization of electrochemically synthesized silver nanoparticles on polyethyleneterephthalate (PET) foil whose essence lies in physical incorporation of particles into thin polymer surface layer induced by polarized excimer laser light. Changes in chemical composition and surface structure of polymer after particle immobilization were recorded by wide range of analytical techniques such as ARXPS, EDX, RBS, AAS, Raman, ICP-MS, DLS, UV-vis, SEM, TEM, and AFM. Thorough analysis of both nanoparticles entering the immobilization step as well as modified PET surface allowed revealing the mechanism of immobilization process itself. Silver nanoparticles were physically embedded into a thin surface layer of polymer reaching several nanometers beneath the surface rather than chemically bonded to PET macromolecules. Laser-implanted nanoparticles open up new possibilities especially in the development of the next generation cell-conform antimicrobial coatings of polymeric materials, namely due to the considerable immobilization strength which is strong enough to prevent particle release into the surrounding environment.

  10. Membranes suited for immobilizing biomolecules

    NARCIS (Netherlands)

    2009-01-01

    The present invention relates to flow-through membranes suitable for the immobilization of biomols., methods for the prepn. of such membranes and the use of such membranes for the immobilization of biomols. and subsequent detection of immobilized biomols. The invention concerns a flow-through

  11. Immobilization: A Revolution in Traditional Brewing

    Science.gov (United States)

    Virkajärvi, Ilkka; Linko, Matti

    In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

  12. Study of the surface crystallization and resistance to dissolution of niobium phosphate glasses for nuclear waste immobilization; Estudo da cristalizacao superficial e da resistencia a dissolucao de vidros niobofosfatos visando a imobilizacao de rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Heveline

    2008-07-01

    The surface crystallization and the dissolution rate of three phosphate glass compositions containing different amounts of niobium oxide were studied. The glasses were named Nb30, Nb37, and Nb44 according to the nominal content of niobium oxide in the glass composition. The three compositions were evaluated keeping the P{sub 2}O{sub 5}/K{sub 2}O ratio constant and varying the amount of Nb{sub 2}O{sub 5}. These glasses were produced by melting appropriate chemical compounds at 1500 deg C for 0.5 hour. The crystalline phases which were nucleated on the glass surface after heat treatment were determined by X-ray diffraction. The crystalline structures depend on the amount of niobium oxide in the glass composition. The crystal morphologies were observed by using an optical microscope, and their characteristics are specific for each kind of crystalline phase. The crystal growth rate and the surface nuclei density were determined for each glass composition, and they depend on each crystalline phase nucleated on the surface. From the differential thermal analysis curves it was determined that the Nb44 glass containing 46.5 mol por cent of niobium oxide is the most thermally stable against crystallization when compared to the Nb30 and Nb37 glasses. According to the activation energies determined for crystal growth on the surface of each glass type, the Nb44 glass can also be considered the most resistant one against crystallization. The dissolution rate for the Nb44 glass after 14 days immersed in an aqueous solution with pH equals to 7 at 90 deg C is the lowest (9.0 x 10{sup -7} g. cm{sup -2} . day{sup -1}) when compared to the other two glass compositions. The dissolution rates in acidic and neutral solutions of all studied glasses meet the international standards for materials which can be used in the immobilization of nuclear wastes. (author)

  13. Factors influencing the surface quality of polished tool steels

    International Nuclear Information System (INIS)

    Rebeggiani, S; Rosén, B-G

    2014-01-01

    Today’s demands on surface quality of moulds for injection moulding of plastic components involve no/low defect contents and roughness levels in the nm-range for high gloss applications. Material properties as well as operating conditions influence the mould finish, and thus the final surface of moulded products. This paper focuses on how particle content and different polishing strategies influence final surface qualities of moulds. Visual estimations of polished tool steel samples were combined with non-contact 3D-surface texture analysis in order to correlate traditional assessments to more quantitative methods, and to be able to analyse the surfaces at nanometre-level. It was found that steels with a lower proportion of particles, like carbides and oxides, gave rise to smoother polished surfaces. In a comparative study of polishers from different polishing shops, it was found that while different surface preparation strategies can lead to similar final roughness, similar preparation techniques can produce high-quality surfaces from different steel grades. However, the non-contact 3D-surface texture analysis showed that not all smooth polished surfaces have desirable functional topographies for injection moulding of glossy plastic components. (paper)

  14. Effect of operational factors on bioregeneration of binary phenol and 4-chlorophenol-loaded granular activated carbon using PVA-immobilized biomass cryogels.

    Science.gov (United States)

    Leong, Kwok-Yii; Adnan, Rohana; Lim, Poh-Eng; Ng, Si-Ling; Seng, Chye-Eng

    2017-09-01

    The effects of dry biomass density in cryogel beads, shaking speed and initial concentration ratio of phenol to 4-chlorophenol (4-CP) on the bioregeneration efficiencies of binary phenol and 4-CP-loaded granular activated carbon (GAC) for phenol and 4-CP, respectively, were investigated under the simultaneous adsorption and biodegradation approach. The results revealed higher bioregeneration efficiencies of binary-loaded GAC for phenol and 4-CP at higher dry biomass density but moderate shaking speed. The optimum dry biomass density in cryogel beads and shaking speed for use in bioregeneration were found to be 0.01 g/mL and 250 rpm, respectively. With respect to the initial phenol to 4-CP concentration ratio, the bioregeneration efficiencies were lower under increasing phenol and 4-CP initial concentrations, respectively, with the effect being more conspicuous under increasing 4-CP concentration. Higher bioregeneration efficiencies were achieved with the use of immobilized rather than suspended biomasses.

  15. Metabolic alkalosis during immobilization in monkeys (M. nemestrina)

    Science.gov (United States)

    Young, D. R.; Yeh, I.; Swenson, R. S.

    1983-01-01

    The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.

  16. Uranium Immobilization in Wetland Soils

    Science.gov (United States)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

  17. Co-Immobilization of Proteins and DNA Origami Nanoplates to Produce High-Contrast Biomolecular Nanoarrays.

    Science.gov (United States)

    Hager, Roland; Burns, Jonathan R; Grydlik, Martyna J; Halilovic, Alma; Haselgrübler, Thomas; Schäffler, Friedrich; Howorka, Stefan

    2016-06-01

    The biofunctionalization of nanopatterned surfaces with DNA origami nanostructures is an important topic in nanobiotechnology. An unexplored challenge is, however, to co-immobilize proteins with DNA origami at pre-determined substrate sites in high contrast relative to the nontarget areas. The immobilization should, in addition, preferably be achieved on a transparent substrate to allow ultrasensitive optical detection. If successful, specific co-binding would be a step towards stoichiometrically defined arrays with few to individual protein molecules per site. Here, we successfully immobilize with high specificity positively charged avidin proteins and negatively charged DNA origami nanoplates on 100 nm-wide carbon nanoislands while suppressing undesired adsorption to surrounding nontarget areas. The arrays on glass slides achieve unprecedented selectivity factors of up to 4000 and allow ultrasensitive fluorescence read-out. The co-immobilization onto the nanoislands leads to layered biomolecular architectures, which are functional because bound DNA origami influences the number of capturing sites on the nanopatches for other proteins. The novel hybrid DNA origami-protein nanoarrays allow the fabrication of versatile research platforms for applications in biosensing, biophysics, and cell biology, and, in addition, represent an important step towards single-molecule protein arrays. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Development of a thiol-ene based screening platform for enzyme immobilization demonstrated using horseradish peroxidase

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Pinelo, Manuel; Woodley, John

    2017-01-01

    Efficient immobilization of enzymes on support surfaces requires an exact match between the surface chemistry and the specific enzyme. A successful match would normally be identified through time consuming screening of conventional resins in multiple experiments testing individual immobilization...... strategies. In this study we present a versatile strategy that largely expands the number of possible surface functionalities for enzyme immobilization in a single, generic platform. The combination of many individual surface chemistries and thus immobilization methods in one modular system permits faster...... functionalization by thiol-ene chemistry (TEC) resulted in the formation of a functional monolayer in each well, whereas, polymer surface grafts were introduced through surface chain transfer free radical polymerization (SCT-FRP). Enzyme immobilization on the modified surfaces was evaluated by using a rhodamine...

  19. Development and Validation of an On-Line Water Toxicity Sensor with Immobilized Luminescent Bacteria for On-Line Surface Water Monitoring.

    NARCIS (Netherlands)

    Woutersen, Marjolijn; van der Gaag, Bram; Abrafi Boakye, Afua; Mink, Jan; Marks, Robert S; Wagenvoort, Arco J; Ketelaars, Henk A M; Brouwer, Bram; Heringa, Minne B

    2017-01-01

    Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for exampleDaphnia magnaorDreissenamussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these

  20. Surface modification of Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} nanocomposites for use in immobilization of glucose oxidase; Modificacao da superficie de nanocompositos de Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} visando seu uso para imobilizacao da glicose oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, I.L.T.; Santos, P.T.A.; Costa, A.C.F.M., E-mail: izabelleliz@hotmail.com, E-mail: patytaraujo@gmail.com, E-mail: ana.costa@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Cornejo, D.R., E-mail: daniel.r.cornejo@gmail.com [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica; Bicalho, S.M.C.M., E-mail: dbrandao@jhs.med.br [JHS Lab. Quimico, Sabara, MG (Brazil); Oliveira, L.S.C., E-mail: libiaconrado@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia Quimica

    2017-04-15

    The increase in the number of people with diabetes in recent years and the high cost-benefit ratio of the existing biosensor technology have increased the interest for the development of glucose detection biosensor based on immobilization of glucose-oxidase (GOD) mainly using magnetic nanoparticles. In this context, nanocomposites of Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} were prepared by combustion reaction and their surface was functionalized with 3-aminopropyltriethoxysilane via silanization reaction and with chitosan via functionalization to obtain a hybrid material that was evaluated as possible GOD immobilizer. The samples were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, transmission electron microscopy, magnetic properties and in vitro cytotoxicity. The results revealed that it was possible to obtain the ferrimagnetic composite, the surface modification reduced the saturation magnetization, but maintained the ferrimagnetic characteristics, and all samples were considered non-toxic. For preliminary testing of the GOD immobilization it was revealed that the nanocomposite modified with silane and chitosan showed the better result, about 2.7 mg of immobilized GOD for 100 mg of nanocomposite, which makes this material a potential alternative to manufacture GOD biosensors. (author)

  1. Immobilized laccase-based biosensor for the detection of disubstituted methyl and methoxy phenols - application of Box-Behnken design with response surface methodology for modeling and optimization of performance parameters.

    Science.gov (United States)

    Sarika, C; Rekha, K; Narasimha Murthy, B

    2016-11-01

    An amperometric principle-based biosensor, employing immobilized laccase enzyme from Trametes versicolor, was developed for the detection of disubstituted methyl and methoxy phenols. Three immobilization methods such as entrapment, cross-linking, and co-cross-linking, with bovine serum albumin (BSA) on nylon membrane have been compared. Among tested methods of immobilization, co-cross-linking method with BSA was superior to the other methods in terms of; sensitivity, limit of detection, response time, and operating stability. The increased sensitivity of the probe optimization of concentrations of laccase, BSA and glutaraldehyde can be achieved by, employing the Box-Behnken design of experiment.

  2. Studeis on the immobilization of water soluble phosphatic fertilizer in some soils with 32P

    International Nuclear Information System (INIS)

    Zhang Yumei; Li Rensheng; Xu Xinyu

    1985-01-01

    Using superphosphate lablled with 32 P, we studied immobilization of water-soluble phosphatic fertilizer on 12 typies of soil. The experimental result showed that major factors to govern immobilization of water-soluble phosphatic fertilizer are: quickly availible Fe that showed positive correlation with the immobilization when it was 4.64-65.72 ppm; and pH that showed negative correlation with the immobilization when it was between 5.35 and 8.88. CaCO 3 and organic matter showed a great effect on the immobilization though there wasn't obvious correlation among them

  3. Immobilization of enzymes by radiation

    International Nuclear Information System (INIS)

    Kaetsu, I.; Kumakura, M.; Yoshida, M.; Asano, M.; Himei, M.; Tamura, M.; Hayashi, K.

    1979-01-01

    Immobilization of various enzymes was performed by radiation-induced polymerization of glass-forming monomers at low temperatures. Alpha-amylase and glucoamylase were effectively immobilized in hydrophilic polymer carrier such as poly(2-hydroxyethyl methacrylate) and also in rather hydrophobic carrier such as poly(tetraethylene-glycol diacrylate). Immobilized human hemoglobin underwent the reversible oxygenation concomitantly with change of oxygen concentration outside of the matrices. (author)

  4. Effects of immobilization on spermiogenesis

    Science.gov (United States)

    Meitner, E. R.

    1980-01-01

    The influence of immobilization stress on spermiogenesis in rats was investigated. After 96 hour immobilization, histological changes began to manifest themselves in the form of practically complete disappearance of cell population of the wall of seminiferous tubule as well as a markedly increased number of cells with pathologic mitoses. Enzymological investigations showed various changes of activity (of acid and alkaline phosphatase and nonspecific esterase) in the 24, 48, and 96 hour immobilization groups.

  5. Immobilization of trichoderma REESEI (QM 9414) cells with paper covered with ionic copolymer by radiation polymerization

    International Nuclear Information System (INIS)

    Lu Zhaoxin

    1992-01-01

    Cationic-hydrophobic copolymer and anionic-hydrophobic copolymer was covered onto surface of paper by radiation polymerization. The paper covered with ionic copolymer was used as carrier of immobilizing Trichoderma reesei cells. Results showed that the cells were immobilized firmly on the carriers and not dislocated from the carriers by shaking. All of FPA of the cells immobilized with the carriers covered with cationic copolymer were higher than that of un-immobilized free cells. The carriers covered with anionic copolymer showed good effect on immobilization of the cells. The weight of immobilized cells increase as increasing the component of DEAEMA in poly (DEAEMA-ATMPT) or decreasing the component of AA in poly (AA-ATMPT). It also increase with the increase of water absorption in poly (DEAEMA-ATMPT) or decrease of water absorption in poly (AA-ATMPT). It shows the static interaction play an important role in the immobilization of cells with ionic copolymer materials

  6. Increase in stability of cellulase immobilized on functionalized magnetic nanospheres

    Science.gov (United States)

    Zhang, Wenjuan; Qiu, Jianhui; Feng, Huixia; Zang, Limin; Sakai, Eiichi

    2015-02-01

    Functionalized magnetic nanospheres were prepared by co-condensation of tetraethylorthosilicate with three different amino-silanes: 3-(2-aminoethylamino propyl)-triethoxysilane (AEAPTES), 3-(2-aminoethylamino propyl)-trimethoxysilane (AEAPTMES) and 3-aminopropyltriethoxysilane (APTES). Then three functionalized magnetic nanospheres were used as supports for immobilization of cellulase. The three functionalized magnetic nanospheres with core-shell morphologies exhibited higher capacity for cellulase immobilization than unfunctionalized magnetic nanospheres. The increasing of surface charge of functionalized magnetic nanospheres leads to an enhancement of the capacity of cellulase immobilization. Particularly, AEAPTMES with methoxy groups was favored to be hydrolyzed and grafted on unfunctionalized magnetic nanospheres than the others. AEAPTMES functionalized magnetic nanospheres with the highest zeta potential (29 mV) exhibited 87% activity recovery and the maximum amount of immobilized cellulase was 112 mg/g support at concentration of initial cellulase of 8 mg/mL. Immobilized cellulase on AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than other immobilized cellulases and free cellulase. In particular, it can be used in about 40 °C, demonstrating the potential of biofuel production using this immobilized cellulase.

  7. Immobilization thresholds of electrofishing relative to fish size

    Science.gov (United States)

    Dolan, C.R.; Miranda, L.E.

    2003-01-01

    Fish size and electrical waveforms have frequently been associated with variation in electrofishing effectiveness. Under controlled laboratory conditions, we measured the electrical power required by five electrical waveforms to immobilize eight fish species of diverse sizes and shapes. Fish size was indexed by total body length, surface area, volume, and weight; shape was indexed by the ratio of body length to body depth. Our objectives were to identify immobilization thresholds, elucidate the descriptors of fish size that were best associated with those immobilization thresholds, and determine whether the vulnerability of a species relative to other species remained constant across electrical treatments. The results confirmed that fish size is a key variable controlling the immobilization threshold and further suggested that the size descriptor best related to immobilization is fish volume. The peak power needed to immobilize fish decreased rapidly with increasing fish volume in small fish but decreased slowly for fish larger than 75-100 cm 3. Furthermore, when we controlled for size and shape, different waveforms did not favor particular species, possibly because of the overwhelming effect of body size. Many of the immobilization inconsistencies previously attributed to species might simply represent the effect of disparities in body size.

  8. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    Energy Technology Data Exchange (ETDEWEB)

    Konwarh, Rocktotpal; Karak, Niranjan [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur-784028, Assam (India); Rai, Sudhir Kumar; Mukherjee, Ashis Kumar [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur-784028, Assam (India)], E-mail: karakniranjan@yahoo.com

    2009-06-03

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe{sub 3}O{sub 4} superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 deg. C and pH 7.2 of the reaction mixture before addition of H{sub 2}O{sub 2} (3% w/w), 2% (w/v) PEG{sub 6000} and 0.062:1 molar ratio of PEG to FeCl{sub 2}{center_dot}4H{sub 2}O. Further statistical optimization using response surface methodology yielded an R{sup 2} value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  9. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    International Nuclear Information System (INIS)

    Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

    2009-01-01

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe 3 O 4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 deg. C and pH 7.2 of the reaction mixture before addition of H 2 O 2 (3% w/w), 2% (w/v) PEG 6000 and 0.062:1 molar ratio of PEG to FeCl 2 ·4H 2 O. Further statistical optimization using response surface methodology yielded an R 2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  10. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    Science.gov (United States)

    Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

    2009-06-01

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  11. Protection zones as a factor of the sustainability of immobile cultural properties in Kosovo and Metohija on the example of monasteries

    Directory of Open Access Journals (Sweden)

    Marković Gordana

    2009-01-01

    Full Text Available The protections zones around immobile cultural properties in Serbia have been determined in compliance with the Law on Cultural Properties and for the purpose of establishing a status of a cultural monument. When reviewing the established status, the coverage of a protection zone was frequently corrected, which confirms that the areas of protected natural and cultural heritage are living organisms that need a change of borders in light of a contemporary urban and regional development. The protection zones around cultural monuments have a particular significance in the context of specific conditions for the survival of the Serbian cultural and spiritual heritage in Kosovo and Metohija. A cultural property is inseparable from the space in which it is located and its full life depends on the fullness of its function, which is also an imperative of a sustainable development. At the same time, integrative protection entails a thorough and multi-disciplinary approach in the process of studying and decision-making. The establishment of protection zones is also conditioned by the inviolable attitude of the owner and user - in this case the Serbian Orthodox Church, but also by the already established status of a cultural property by the Serbian Protection Service. It is also necessary to achieve the basic security conditions in the region with a high conflict risk. In addition, there is a significant expert participation of international institutions with regards to the defining of the criteria for the establishment of the zones, and there are also tendencies of the local community in Kosovo and Metohija. The practice has confirmed difficulties in harmonizing all positions related to the establishment of zones and particularly in defining the mechanisms for the management of the zones. In those terms, it is necessary to have an integration of legal regulations and cultural policy, establishment of the widest possible cooperation at all levels and the

  12. Enhanced performance of a glucose/O(2) biofuel cell assembled with laccase-covalently immobilized three-dimensional macroporous gold film-based biocathode and bacterial surface displayed glucose dehydrogenase-based bioanode.

    Science.gov (United States)

    Hou, Chuantao; Yang, Dapeng; Liang, Bo; Liu, Aihua

    2014-06-17

    The power output and stability of enzyme-based biofuel cells (BFCs) is greatly dependent on the properties of both the biocathode and bioanode, which may be adapted for portable power production. In this paper, a novel highly uniform three-dimensional (3D) macroporous gold (MP-Au) film was prepared by heating the gold "supraspheres", which were synthesized by a bottom-up protein templating approach, and followed by modification of laccase on the MP-Au film by covalent immobilization. The as-prepared laccase/MP-Au biocathode exihibited an onset potential of 0.62 V versus saturated calomel electrode (SCE, or 0.86 V vs NHE, normal hydrogen electrode) toward O2 reduction and a high catalytic current of 0.61 mAcm(-2). On the other hand, mutated glucose dehydrogenase (GDH) surface displayed bacteria (GDH-bacteria) were used to improve the stability of the glucose oxidation at the bioanode. The as-assembled membraneless glucose/O2 fuel cell showed a high power output of 55.8 ± 2.0 μW cm(-2) and open circuit potential of 0.80 V, contributing to the improved electrocatalysis toward O2 reduction at the laccase/MP-Au biocathode. Moreover, the BFC retained 84% of its maximal power density even after continuous operation for 55 h because of the high stability of the bacterial surface displayed GDH mutant toward glucose oxidation. Our findings may be promising for the development of more efficient glucose BFC for portable battery or self-powered device applications.

  13. Quality factor due to roughness scattering of shear horizontal surface acoustic waves in nanoresonators

    NARCIS (Netherlands)

    Palasantzas, G.

    2008-01-01

    In this work we study the quality factor associated with dissipation due to scattering of shear horizontal surface acoustic waves by random self-affine roughness. It is shown that the quality factor is strongly influenced by both the surface roughness exponent H and the roughness amplitude w to

  14. Determining eyeball surface area directly exposed to the effects of external factors.

    Science.gov (United States)

    Juliszewski, Tadeusz; Kadłuczka, Filip; Kiełbasa, Paweł

    2016-01-01

    This article discusses determining the surface area of eyeballs of men and women exposed to the direct effects of external factors in the working environment. For one eye, the mean surface is 172-182 mm(2). The determined surface area can be used in formulas for calculating the exposure of eyeballs to harmful chemical substances in workplace air.

  15. Modeling wind adjustment factor and midflame wind speed for Rothermel's surface fire spread model

    Science.gov (United States)

    Patricia L. Andrews

    2012-01-01

    Rothermel's surface fire spread model was developed to use a value for the wind speed that affects surface fire, called midflame wind speed. Models have been developed to adjust 20-ft wind speed to midflame wind speed for sheltered and unsheltered surface fuel. In this report, Wind Adjustment Factor (WAF) model equations are given, and the BehavePlus fire modeling...

  16. Surface modification of strontium-doped porous bioactive ceramic scaffolds via poly(DOPA) coating and immobilizing silk fibroin for excellent angiogenic and osteogenic properties.

    Science.gov (United States)

    Wang, Xu; Gu, Zhipeng; Jiang, Bo; Li, Li; Yu, Xixun

    2016-04-01

    For bioceramic scaffolds employed in clinical applications, excellent bioactivity and tenacity were of great importance. Modifying inorganic SCPP scaffolds with biological macromolecules could obviously improve its bioactivity and eliminate its palpable brittleness. However, it was hard to execute directly due to extremely bad interfacial compatibility between them. In this research, dopamine (DOPA) was introduced onto strontium-doped calcium polyphosphate (SCPP) scaffolds, subsequently the preliminary material was successfully further modified by silk fibroin (SF). SCPP/D/SF possessed suitable biomechanical properties, ability to stimulate angiogenic factor secretion and excellent biocompatibility. Biomechanical examination demonstrated that SCPP/D/SF scaffolds yielded better compressive strength because of improved interfacial compatibility. MTT assay and CLSM observation showed that SCPP/D/SF scaffolds had good cytocompatibility and presented better inducing-cell-migration potential than pure SCPP scaffolds. Meanwhile, its ability to stimulate angiogenic factor secretion was measured through the ELISA assay and immunohistological analysis in vitro and in vivo respectively. The results revealed, superior to SCPP, SCPP/D/SF could effectively promote VEGF and bFGF expression, possibly leading to enhancing angiogenesis and osteogenesis. In a word, SCPP/D/SF could serve as a potential bone tissue engineering scaffold for comparable biomechanical properties and excellent bioactivity. It provided a novel idea for modification of inorganic materials to prepare promising bone tissue engineering scaffolds with the ability to accelerate bone regeneration and vascularization.

  17. Encapsulation of Platelet in Kefiran Polymer and Detection of Bioavailability of Immobilized Platelet in Probiotic Kefiran as A New Drug for Surface Bleeding

    Directory of Open Access Journals (Sweden)

    Anahita Jenab

    2015-11-01

    Full Text Available Background : Kefir contains lactic acid bacteria (Lactobacillus, Lactococcus, Leuconostoc, Acetobacter and Streptococcus and yeasts (Kluyveromyces, Torula, Candida, Saccharomyces .Kefiran is the polysaccharide produced by lactic acid bacteria in kefir.Methods : Kefiran was prepared from milk containing 0.5% fat and 10 grams kefir grains and was separated from kefir by ethanol (0.02 gram following entrapping the platelets to this polymer. Ligand of the platelet-polysaccharide was studied by FTIR.Results : FTIR results showed that the bands of C-O and C-O-C connections were formed and the polysaccharides had been attached to the receptors of the platelet glycoproteins (GP Ib,GPIIb / IIIa. Stability and encapsulation of the platelet and kefiran were assessed by Coulter Counter. Encapsulation of the platelets by polysaccharide at the beginning caused to reduce the number of platelets following by releasing of 50% of the platelets after 3 hours.Conclusion : The platelets were encapsulated in kefiran polymer and detected for bioavailability as new drug for surface bleeding. Also, kefiran has antimicrobial and antifungal properties. On the other hand, the existence of nisin in kefiran could be useful as an antibacterial lantibiotic. 

  18. Biodegradation of chlorobenzene using immobilized crude extracts ...

    African Journals Online (AJOL)

    SERVER

    2007-10-04

    Oct 4, 2007 ... immobilized crude extracts were reused for all other experiments and found that immobilization .... India which are of analytical reagent grade. .... 9. 60. 3. 1. Figure 3. Degradation of chlorobenzene by immobilized crude.

  19. Characterization of modified zeolite as microbial immobilization media on POME anaerobic digestion

    Science.gov (United States)

    Cahyono, Rochim B.; Ismiyati, Sri; Ginting, Simparmin Br; Mellyanawaty, Melly; Budhijanto, Wiratni

    2018-03-01

    As the world’s biggest palm oil producer, Indonesia generates also huge amount of Palm Oil Mill Effluent (POME) wastewater and causes serious problem in environment. In conventional method, POME was converted into biogas using lagoon system which required extensive land area. Anaerobic Fluidized Bed Reactor (AFBR) proposes more effective biogas producing with smaller land area. In the proposed system, a immobilization media would be main factor for enhancing productivity. This research studied on characterization of Lampung natural zeolite as immobilization media in the AFBR system for POME treatment. Various activation method such as physical and chemical were attempted to create more suitable material which has larger surface area, pore size distribution as well as excellent surface structures. The physical method was applied by heating up the material till 400°C while HCl was used on the chemical activation. Based on the result, the chemical activation increased the surface area significantly into 71 m2/g compared to physical as well as original zeolite. The strong acid material was quite effective to enforce the impurities within zeolite pore structure compared to heating up the material. According to distribution data, the Lampung zeolite owned the pore size with the range of 3 – 5 μm which was mesopore material. The pore size was appropriate for immobilization media as it was smaller than size of biogas microbial. The XRD patterns verified that chemical activation could maintain the zeolite structure as the original. Obviously, the SEM photograph showed apparent structure and pore size on the modified zeolite using chemical method. The testing of modified zeolite on the batch system was done to evaluate the characterization process. The modified zeolite using chemical process resulted fast reduction of COD and stabilized the volatile fatty acid as the intermediate product of anaerobic digestion, especially in the beginning of the process. Therefore, the

  20. Modification of palygorskite surface by organofunctionalization for application in immobilization of H{sub 3}PW{sub 12}O{sub 40}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lixia; Jin Qingzhe; Huang Jianhua; Liu Yuanfa; Shan Liang [State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, Jiangsu Province (China); Wang Xingguo, E-mail: wxg1002@hotmail.com [State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, Jiangsu Province (China)

    2010-08-01

    Modified palygorskite with 3-aminopropyltriethoxysilane (KH550) and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (KH792) were used as adsorbent supports for adsorption of 12-phosphotungstic acid (H{sub 3}PW{sub 12}O{sub 40}, HPW). The effect of some factors, such as adsorbent dosage, contact time, initial HPW concentration and temperature, was investigated. The experimental data were well fitted with the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model at all studied temperatures. The physicochemical properties of the solids were characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis-simultaneous differential thermal analysis (TGA-SDTA), and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy analysis techniques. The characteristic results indicated that silylated-Pa was a suitable support for adsorption of HPW; and HPW was finely and effectively distributed on silylated-Pa and retained partly strong Bronsted acidity.

  1. Iodine immobilization in apatites

    International Nuclear Information System (INIS)

    Audubert, F.; Lartigue, J.E.

    2000-01-01

    In the context of a scientific program on long-lived radionuclide conditioning, a matrix for iodine 129 immobilization has been studied. A lead vanado-phosphate apatite was prepared from the melt of lead vanado-phosphate Pb 3 (VO 4 ) 1.6 (PO 4 ) 0.4 and lead iodide PbI 2 in stoichiometric proportions by calcination at 700 deg. C during 3 hours. Natural sintering of this apatite is not possible because the product decomposition occurs at 400 deg. C. Reactive sintering is the solution. The principle depends on the coating of lead iodide with lead vanado-phosphate. Lead vanado-phosphate coating is used as iodo-apatite reactant and as dense covering to confine iodine during synthesis. So the best condition to immobilize iodine during iodo-apatite synthesis is a reactive sintering at 700 deg. C under 25 MPa. We obtained an iodo-apatite surrounded with dense lead vanadate. Leaching behaviour of the matrix synthesized by solid-solid reaction is under progress in order to determine chemical durability, basic mechanisms of the iodo-apatite alteration and kinetic rate law. Iodo-apatite dissolution rates were pH and temperature dependent. We obtained a rate of 2.5 10 -3 g.m -2 .d -1 at 90 deg. C in initially de-ionised water. (authors)

  2. Pigment Production from Immobilized Monascus sp. Utilizing Polymeric Resin Adsorption

    OpenAIRE

    Evans, Patrick J.; Wang, Henry Y.

    1984-01-01

    Pigment production by the fungus Monascus sp. was studied to determine why Monascus sp. provides more pigment in solid culture than in submerged culture. Adding a sterilized nonionic polymeric adsorbent resin directly to the growing submerged culture did not enhance the pigment production, thus indicating that pigment extraction is probably not a factor. Monascus cells immobilized in hydrogel were studied and exhibited decreased pigment production as a result of immobilization. This result is...

  3. Cellulase immobilization on magnetic nanoparticles encapsulated in polymer nanospheres.

    Science.gov (United States)

    Lima, Janaina S; Araújo, Pedro H H; Sayer, Claudia; Souza, Antonio A U; Viegas, Alexandre C; de Oliveira, Débora

    2017-04-01

    Immobilization of cellulases on magnetic nanoparticles, especially magnetite nanoparticles, has been the main approach studied to make this enzyme, economically and industrially, more attractive. However, magnetite nanoparticles tend to agglomerate, are very reactive and easily oxidized in air, which has strong impact on their useful life. Thus, it is very important to provide proper surface coating to avoid the mentioned problems. This study aimed to investigate the immobilization of cellulase on magnetic nanoparticles encapsulated in polymeric nanospheres. The support was characterized in terms of morphology, average diameter, magnetic behavior and thermal decomposition analyses. The polymer nanospheres containing encapsulated magnetic nanoparticles showed superparamagnetic behavior and intensity average diameter about 150 nm. Immobilized cellulase exhibited broader temperature stability than in the free form and great reusability capacity, 69% of the initial enzyme activity was maintained after eight cycles of use. The magnetic support showed potential for cellulase immobilization and allowed fast and easy biocatalyst recovery through a single magnet.

  4. Antibody Immobilization on Conductive Polymer Coated Nonwoven Fibers for Biosensors

    Directory of Open Access Journals (Sweden)

    Shannon K. MCGRAW

    2011-12-01

    Full Text Available This work is being performed to develop rapid and novel electrochemical biosensors for foodborne pathogen detection. This research focuses on electrotextile platforms to perform both capture and sensing functions in a single component. The biosensor uses nonwoven fiber membranes coated with conductive polymer and functionalized with antibodies for biological capture. This study examines three methods for antibody immobilization: passive adsorption, glutaraldehyde cross-linking, and EDC/Sulfo-NHS cross-linking. Antibodies are immobilized onto the conductive fiber surfaces for the specific capture of a target pathogen. The immobilization and capture capabilities of each method are analyzed through the use of two different fluorescent reporters: FITC and PicoGreen DNA stain. Fluorescence is measured using a fluorescent plate reader and then imaged using a fluorescent microscope. The effect of a blocking agent on specificity is also evaluated. It is found that glutaraldehyde with blocking is the best immobilization method with PicoGreen being the best fluorescent reporter.

  5. Diesel oil removal by immobilized Pseudoxanthomonas sp. RN402.

    Science.gov (United States)

    Nopcharoenkul, Wannarak; Netsakulnee, Parichat; Pinyakong, Onruthai

    2013-06-01

    Pseudoxanthomonas sp. RN402 was capable of degrading diesel, crude oil, n-tetradecane and n-hexadecane. The RN402 cells were immobilized on the surface of high-density polyethylene plastic pellets at a maximum cell density of 10(8) most probable number (MPN) g(-1) of plastic pellets. The immobilized cells not only showed a higher efficacy of diesel oil removal than free cells but could also degrade higher concentrations of diesel oil. The rate of diesel oil removal by immobilized RN402 cells in liquid culture was 1,050 mg l(-1) day(-1). Moreover, the immobilized cells could maintain high efficacy and viability throughout 70 cycles of bioremedial treatment of diesel-contaminated water. The stability of diesel oil degradation in the immobilized cells resulted from the ability of living RN402 cells to attach to material surfaces by biofilm formation, as was shown by CLSM imaging. These characteristics of the immobilized RN402 cells, including high degradative efficacy, stability and flotation, make them suitable for the purpose of continuous wastewater bioremediation.

  6. Treatment and immobilization of intermediate-level radioactive wastes

    International Nuclear Information System (INIS)

    Lerch, R.E.; Greenhalgh, W.O.; Partridge, J.A.; Richardson, G.L.

    1979-01-01

    A new program underway at the Hanford Engineering Development Laboratory (HEDL) to develop and demonstrate treatment and immobilization technologies for intermediate-level wastes (ILW) generated in the nuclear fuel cycle is discussed. ILW are defined as those liquid and solid radioactive wastes, other than high-level wastes and fuel cladding hulls, that in packaged form have radiation dose readings greater than 200 millirem/hr at the packaged surface and 10 millirem/hr at three feet from the surface. The IAEA value of 10 4 Ci/m 3 for ILW defines the upper limit. For comparative purposes, reference is also made to certain aspects of low-level radioactive wastes (LLW). Initial work has defined the sources, quantities and types of wastes which comprise ILW. Because of the wide differences in composition (e.g., acids, salt solutions, resins and zeolites, HEPA filters, etc.) the wastes may require different treatments, particularly those wastes containing volatile contaminants. The various types of ILW have been grouped into categories amenable to similar treatment. Laboratory studies are underway to define treatment technologies for liquid ILW which contain volatile contaminants and to define immobilization parameters for the residues resulting from treatment of ILW. Immobilization agents initially being evaluated for the various residues include cement, urea-formaldehyde, and bitumen although other immobilization agents will be studied. The program also includes development of acceptable test procedures for the final immobilized products as well as development of proposed criteria for storage, transportation, and disposal of the immobilized ILW

  7. Covalent immobilization of lipases on monodisperse magnetic microspheres modified with PAMAM-dendrimer

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Weiwei [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China); Zhang, Yimei [Suzhou Research Academy of North China Electric Power University (China); Hou, Chen; Pan, Duo; He, Jianjun; Zhu, Hao, E-mail: zhuhao07@lzu.edu.cn [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China)

    2016-02-15

    This paper reported an immobilization of Candida rugosa lipase (CRL) onto PAMAM-dendrimer-grafted magnetic nanoparticles synthesized by a modified solvothermal reduction method. The dendritic magnetic nanoparticles were amply characterized by several instrumental measurements, and the CRL was covalently anchored on the three generation supports with glutaraldehyde as coupling reagent. The amount of immobilized enzyme was up to 150 mg/g support and the factors related with the enzyme activity were investigated. The immobilization of lipase improved their performance in wider ranges of pH and temperature. The immobilized lipase exhibited excellent thermal stability and reusability in comparison with free enzyme and can be reused 10 cycles with the enzymatic activity remained above 90 %. The properties of lipase improved obviously after being immobilized on the dendritic supports. The inactive immobilized lipase could be regenerated with glutaraldehyde and Cu{sup 2+}, respectively. This synthetic strategy was facile and eco-friendly for applications in lipase immobilization.

  8. Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi 2 Se 3

    KAUST Repository

    Kong, Desheng

    2011-06-28

    Bismuth selenide (Bi2Se3) is a topological insulator with metallic surface states (SS) residing in a large bulk bandgap. In experiments, synthesized Bi2Se3 is often heavily n-type doped due to selenium vacancies. Furthermore, it is discovered from experiments on bulk single crystals that Bi2Se3 gets additional n-type doping after exposure to the atmosphere, thereby reducing the relative contribution of SS in total conductivity. In this article, transport measurements on Bi2Se3 nanoribbons provide additional evidence of such environmental doping process. Systematic surface composition analyses by X-ray photoelectron spectroscopy reveal fast formation and continuous growth of native oxide on Bi2Se3 under ambient conditions. In addition to n-type doping at the surface, such surface oxidation is likely the material origin of the degradation of topological SS. Appropriate surface passivation or encapsulation may be required to probe topological SS of Bi2Se3 by transport measurements. © 2011 American Chemical Society.

  9. Assessing attitudes toward spinal immobilization.

    Science.gov (United States)

    Bouland, Andrew J; Jenkins, J Lee; Levy, Matthew J

    2013-10-01

    Prospective studies have improved knowledge of prehospital spinal immobilization. The opinion of Emergency Medical Services (EMS) providers regarding spinal immobilization is unknown, as is their knowledge of recent research advances. To examine the attitudes, knowledge, and comfort of prehospital and Emergency Department (ED) EMS providers regarding spinal immobilization performed under a non-selective protocol. An online survey was conducted from May to July of 2011. Participants were drawn from the Howard County Department of Fire and Rescue Services and the Howard County General Hospital ED. The survey included multiple choice questions and responses on a modified Likert scale. Correlation analysis and descriptive data were used to analyze results. Comfort using the Kendrick Extrication Device was low among ED providers. Experienced providers were more likely to indicate comfort using this device. Respondents often believed that spinal immobilization is appropriate in the management of penetrating trauma to the chest and abdomen. Reported use of padding decreased along with the frequency with which providers practice and encounter immobilized patients. Respondents often indicated that they perform spinal immobilization due solely to mechanism of injury. Providers who feel as if spinal immobilization is often performed unnecessarily were more likely to agree that immobilization causes an unnecessary delay in patient care. The results demonstrate the need for improved EMS education in the use of the Kendrick Extrication Device, backboard padding, and spinal immobilization in the management of penetrating trauma. The attitudes highlighted in this study are relevant to the implementation of a selective spinal immobilization protocol. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Engineering of PDMS surfaces for use in microsystems for capture and isolation of complex and biomedically important proteins: epidermal growth factor receptor as a model system.

    Science.gov (United States)

    Lowe, Aaron M; Ozer, Byram H; Wiepz, Gregory J; Bertics, Paul J; Abbott, Nicholas L

    2008-08-01

    Elastomers based on poly(dimethylsiloxane) (PDMS) are promising materials for fabrication of a wide range of microanalytical systems due to their mechanical and optical properties and ease of processing. To date, however, quantitative studies that demonstrate reliable and reproducible methods for attachment of binding groups that capture complex receptor proteins of relevance to biomedical applications of PDMS microsystems have not been reported. Herein we describe methods that lead to the reproducible capture of a transmembrane protein, the human epidermal growth factor (EGF) receptor, onto PDMS surfaces presenting covalently immobilized antibodies for EGF receptor, and subsequent isolation of the captured receptor by mechanical transfer of the receptor onto a chemically functionalized surface of a gold film for detection. This result is particularly significant because the physical properties of transmembrane proteins make this class of proteins a difficult one to analyze. We benchmark the performance of antibodies to the human EGF receptor covalently immobilized on PDMS against the performance of the same antibodies physisorbed to conventional surfaces utilized in ELISA assays through the use of EGF receptor that was (32)P-radiolabeled in its autophosphorylation domain. These results reveal that two pan-reactive antibodies for the EGF receptor (clones H11 and 111.6) and one phosphospecific EGF receptor antibody (clone pY1068) capture the receptor on both PDMS and ELISA plates. When using H11 antibody to capture EGF receptor and subsequent treatment with a stripping buffer (NaOH and sodium dodecylsulfate) to isolate the receptor, the signal-to-background obtained using the PDMS surface was 82 : 1, exceeding the signal-to-background measured on the ELISA plate (<48 : 1). We also characterized the isolation of captured EGF receptor by mechanical contact of the PDMS surface with a chemically functionalized gold film. The efficiency of mechanical transfer of the

  11. Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi 2 Se 3

    KAUST Repository

    Kong, Desheng; Cha, Judy J.; Lai, Keji; Peng, Hailin; Analytis, James G.; Meister, Stefan; Chen, Yulin; Zhang, Hai-Jun; Fisher, Ian R.; Shen, Zhi-Xun; Cui, Yi

    2011-01-01

    Bismuth selenide (Bi2Se3) is a topological insulator with metallic surface states (SS) residing in a large bulk bandgap. In experiments, synthesized Bi2Se3 is often heavily n-type doped due to selenium vacancies. Furthermore, it is discovered from

  12. Synthesis, structure, properties and immobilization on a gold surface of the monoribbed-functionalized tris-dioximate cobalt(II) clathrochelates and an electrocatalytic hydrogen production from H+ ions.

    Science.gov (United States)

    Voloshin, Y Z; Belov, A S; Vologzhanina, A V; Aleksandrov, G G; Dolganov, A V; Novikov, V V; Varzatskii, O A; Bubnov, Y N

    2012-05-28

    The cycloaddition of the mono- and dichloroglyoximes to the cobalt(II) bis-α-benzyldioximate afforded the cobalt(II) mono- and dichloroclathrochelates in moderate yields (40-60%). These complexes undergo nucleophilic substitution of their reactive chlorine atoms with aliphatic amines, alcohols and thiolate anions. In the case of ethylenediamine and 1,2-ethanedithiol, only the macrobicyclic products with α,α'-N(2)- and α,α'-S(2)-alicyclic six-numbered ribbed fragments were obtained. The cobalt(II) cage complexes with terminal mercapto groups were synthesized using aliphatic dithiols. The crystal and molecular structures of the six cobalt(II) clathrochelates were obtained by X-ray diffraction. Their CoN(6)-coordination polyhedra possess a geometry intermediate between a trigonal prism and a trigonal antiprism, and the encapsulated cobalt(II) ions are shifted from their centres due to the structural Jahn-Teller effect with the Co-N distances varying significantly (by 0.10-0.26 Å). The electrochemistry of the complexes obtained was studied by cyclic voltammetry (CV). The anodic waves correspond to the quasi-reversible Co(2+/3+) oxidations, whereas the cathodic ranges contain the quasi-reversibile waves assigned to the Co(2+/+) reductions; all the cobalt(i)-containing clathrochelate anions formed are stable in the CV time scale. The electrocatalytic properties of the cobalt complexes obtained were studied in the production of hydrogen from H(+) ions: the addition of HClO(4) resulted in the formation of the same catalytic cathodic reduction Co(2+/+) waves. The controlled-potential electrolysis with gas chromatography analysis confirmed the production of H(2) in high Faraday yields. The efficiency of this electrocatalytic process was enhanced by an immobilization of the complexes with terminal mercapto groups on a surface of the working gold electrode.

  13. HLW immobilization in glass

    International Nuclear Information System (INIS)

    Leroy, P.; Jacquet-Francillon, N.; Runge, S.

    1992-01-01

    The immobilization of High Level Waste in glass in France is a long history which started as early as in the 1950's. More than 30 years of Research and Development have been invested in that field. Two industrial facilities are operating (AVM and R7) and a third one (T7), under cold testing, is planned to start active operation in the mid-92. While vitrification has been demonstrated to be an industrially mastered process, the question of the quality of the final waste product, i.e. the HLW glass, must be addressed. The scope of the present paper is to focus on the latter point from both standpoints of the R and D and of the industrial reality

  14. Effect of heparin and alendronate coating on titanium surfaces on inhibition of osteoclast and enhancement of osteoblast function

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Ho-Jin; Yun, Young-Pil [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Han, Choong-Wan; Kim, Min Sung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Sung Eun; Bae, Min Soo [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Gyu-Tae; Choi, Yong-Suk; Hwang, Eui-Hwan [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Lee, Joon Woo [Department of Technology Commercialization Information, Korea Institute of Science and Technology Information (KISTI), 66, Hoegi-ro, Dongdaemun-gu, Seoul 130-741 (Korea, Republic of); Lee, Jin-Moo; Lee, Chang-Hoon [Department of Oriental Gynecology, College of Oriental Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Duck-Su [Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kwon, Il Keun, E-mail: kwoni@khu.ac.kr [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

    2011-09-23

    Highlights: {yields} We examine bone metabolism of engineered alendronate attached to Ti surfaces. {yields} Alendronate-immobilized Ti enhances activation of osteoblast differentiation. {yields} Alendronate-immobilized Ti inhibits osteoclast differentiation. {yields} Alendronate-immobilized Ti may be a bioactive implant with dual functions. -- Abstract: The failure of orthopedic and dental implants has been attributed mainly to loosening of the implant from host bone, which may be due to weak bonding of the implant material to bone tissue. Titanium (Ti) is used in the field of orthopedic and dental implants because of its excellent biocompatibility and outstanding mechanical properties. Therefore, in the field of materials science and tissue engineering, there has been extensive research to immobilize bioactive molecules on the surface of implant materials in order to provide the implants with improved adhesion to the host bone tissue. In this study, chemically active functional groups were introduced on the surface of Ti by a grafting reaction with heparin and then the Ti was functionalized by immobilizing alendronate onto the heparin-grafted surface. In the MC3T3-E1 cell osteogenic differentiation study, the alendronate-immobilized Ti substrates significantly enhanced alkaline phosphatase activity (ALP) and calcium content. Additionally, nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation of RAW264.7 cells was inhibited with the alendronate-immobilized Ti as confirmed by TRAP analysis. Real time PCR analysis showed that mRNA expressions of osteocalcin and osteopontin, which are markers for osteogenesis, were upregulated in MC3T3-E1 cells cultured on alendronate-immobilized Ti. The mRNA expressions of TRAP and Cathepsin K, markers for osteoclastogenesis, in RAW264.7 cells cultured on alendronate-immobilized Ti were down-regulated. Our study suggests that alendronate-immobilized Ti may be a bioactive implant with dual functions to enhance

  15. CORROSION AND SURFACE PROTECTION IN MACHINE MATERIALS FRICTION HAVE DIFFERENT SURFACE PAIRS EXPERIMENTAL INVESTIGATION OF FACTORS

    Directory of Open Access Journals (Sweden)

    Senai YALCINKAYA

    2017-05-01

    Full Text Available Friction force, normal force, linear change. The normal force varies with the loads on the friction object. In order to determine the friction force and the friction coefficient, the friction object and the friction speed are used. The experimental work was carried out in three stages. In the first stage, the effect of normal force on the friction force was studied. In the second step, the friction force of the friction surface area is influenced. The effect of the change of the shear rate in step 3 on the friction force was investigated. At the last stage, the experimental study of the effect of the material selection on the friction force was made and it was seen that the aluminum / brass surface pair had the smallest friction coefficient as a result of the opening. The greatest coefficient of friction is found in the pair of glass / felt objects.

  16. Fluctuation correlation models for receptor immobilization

    Science.gov (United States)

    Fourcade, B.

    2017-12-01

    Nanoscale dynamics with cycles of receptor diffusion and immobilization by cell-external-or-internal factors is a key process in living cell adhesion phenomena at the origin of a plethora of signal transduction pathways. Motivated by modern correlation microscopy approaches, the receptor correlation functions in physical models based on diffusion-influenced reaction is studied. Using analytical and stochastic modeling, this paper focuses on the hybrid regime where diffusion and reaction are not truly separable. The time receptor autocorrelation functions are shown to be indexed by different time scales and their asymptotic expansions are given. Stochastic simulations show that this analysis can be extended to situations with a small number of molecules. It is also demonstrated that this analysis applies when receptor immobilization is coupled to environmental noise.

  17. CORROSION AND SURFACE PROTECTION IN MACHINE MATERIALS FRICTION HAVE DIFFERENT SURFACE PAIRS EXPERIMENTAL INVESTIGATION OF FACTORS

    OpenAIRE

    Senai YALCINKAYA

    2017-01-01

    Friction force, normal force, linear change. The normal force varies with the loads on the friction object. In order to determine the friction force and the friction coefficient, the friction object and the friction speed are used. The experimental work was carried out in three stages. In the first stage, the effect of normal force on the friction force was studied. In the second step, the friction force of the friction surface area is influenced. The effect of the change of the s...

  18. Factors Affecting Optimal Surface Roughness of AISI 4140 Steel in Turning Operation Using Taguchi Experiment

    Science.gov (United States)

    Novareza, O.; Sulistiyarini, D. H.; Wiradmoko, R.

    2018-02-01

    This paper presents the result of using Taguchi method in turning process of medium carbon steel of AISI 4140. The primary concern is to find the optimal surface roughness after turning process. The taguchi method is used to get a combination of factors and factor levels in order to get the optimum surface roughness level. Four important factors with three levels were used in experiment based on Taguchi method. A number of 27 experiments were carried out during the research and analysed using analysis of variance (ANOVA) method. The result of surface finish was determined in Ra type surface roughness. The depth of cut was found to be the most important factors for reducing the surface roughness of AISI 4140 steel. On the contrary, the other important factors i.e. spindle speed and rake side angle of the tool were proven to be less factors that affecting the surface finish. It is interesting to see the effect of coolant composition that gained the second important factors to reduce the roughness. It may need further research to explain this result.

  19. Hydrophilic PCU scaffolds prepared by grafting PEGMA and immobilizing gelatin to enhance cell adhesion and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Changcan; Yuan, Wenjie; Khan, Musammir; Li, Qian [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Key Laboratory of Systems Bioengineering of Ministry of Education, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin) Tianjin 300072 (China); Yao, Fanglian [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Key Laboratory of Systems Bioengineering of Ministry of Education, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Tianjin 300072 (China); Zhang, Wencheng, E-mail: wenchengzhang@yahoo.com [Department of Physiology and Pathophysiology, Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China)

    2015-05-01

    Gelatin contains many functional motifs which can modulate cell specific adhesion, so we modified polycarbonate urethane (PCU) scaffold surface by immobilization of gelatin. PCU-g-gelatin scaffolds were prepared by direct immobilizing gelatins onto the surface of aminated PCU scaffolds. To increase the immobilization amount of gelatin, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto PCU scaffolds by surface initiated atom transfer radical polymerization. Then, following amination and immobilization, PCU-g-PEGMA-g-gelatin scaffolds were obtained. Both modified scaffolds were characterized by chemical and biological methods. After immobilization of gelatin, the microfiber surface became rough, but the original morphology of scaffolds was maintained successfully. PCU-g-PEGMA-g-gelatin scaffolds were more hydrophilic than PCU-g-gelatin scaffolds. Because hydrophilic PEGMA and gelatin were grafted and immobilized onto the surface, the PCU-g-PEGMA-g-gelatin scaffolds showed low platelet adhesion, perfect anti-hemolytic activity and excellent cell growth and proliferation capacity. It could be envisioned that PCU-g-PEGMA-g-gelatin scaffolds might have potential applications in tissue engineering artificial scaffolds. - Graphical abstract: PCU-g-gelatin scaffolds were prepared by direct immobilizing gelatin onto the surface of aminated PCU scaffolds (method a). To increase the immobilization amount of gelatin, PEGMAs were grafted onto the scaffold surface by SI-ATRP. PCU-g-PEGMA-g-gelatin scaffolds were prepared by method b. The gelatin modified scaffolds exhibited high hydrophilicity, low platelet adhesion, perfect anti-hemolytic activity, and excellent cell adhesion and proliferation capacity. They might have potential applications as tissue engineering scaffolds for artificial blood vessels. - Highlights: • Hydrophilic scaffolds were prepared by grafting PEGMA and immobilization of gelatins. • Grafting PEGMA enhanced the immobilization amount of gelatin

  20. N-Confused Porphyrin Immobilized on Solid Supports: Synthesis and Metal Ions Sensing Efficacy

    Directory of Open Access Journals (Sweden)

    Sara R. D. Gamelas

    2018-04-01

    Full Text Available In this work, the N-confused porphyrin 5,10,15,20-tetraphenyl-2-aza-21-carbaporphyrin (NCTPP was immobilized on neutral or cationic supports based on silica and on Merrifield resin. The new materials were characterized by appropriate techniques (UV-Vis spectroscopy, SEM, and zeta potential analysis. Piezoelectric quartz crystal gold electrodes were coated with the different hybrids and their ability to interact with heavy metals was evaluated. The preliminary results obtained showed that the new materials can be explored for metal cations detection and the modification of the material surface is a key factor in tuning the metal selectivity.

  1. Experimental analysis on removal factor of smear method in measurement of surface contamination

    International Nuclear Information System (INIS)

    Sugiura, Nobuyuki; Taira, Junichi; Takenaka, Keisuke; Yamanaka, Kazuo; Sugai, Kenji; Kosako, Toshiso

    2007-01-01

    The smear test is one of the important ways to measure surface contamination. The loose contamination under the high background radiation, which is more significant in handling non-sealed radioisotopes, can be evaluated by this method. The removal factor is defined as the ratio of the activity removed from the surface by one smear to the whole activity of the removable surface contamination. The removal factor is greatly changed by the quality and condition of surface materials. In this study, the values of removal factor at several typical surface conditions were evaluated experimentally and the practical application of those values was considered. It is required the smear should be pressed by moderate pressure when wiping the surface. The pressure from 1.0 kg to 1.5 kg per filter paper was recommended. The removal factor showed lower value in wiping by the pressure below 1.0 kg. The value of 0.5 for the removal factor could be applied to the smooth surface of linoleum, concrete coated with paint or epoxy resin, stainless steel and glass with the statistical allowance. (author)

  2. Enzyme-immobilized SiO2-Si electrode: Fast interfacial electron transfer with preserved enzymatic activity

    Science.gov (United States)

    Wang, Gang; Yau, Siu-Tung

    2005-12-01

    The enzyme, glucose oxidase (GOx), is immobilized using electrostatic interaction on the native oxide of heavily doped n-type silicon. Voltammetric measurement shows that the immobilized GOx gives rise to a very fast enzyme-silicon interfacial electron transfer rate constant of 7.9s-1. The measurement also suggests that the enzyme retains its native conformation when immobilized on the silicon surface. The preserved native conformation of GOx is further confirmed by testing the enzymatic activity of the immobilized GOx using glucose. The GOx-immobilized silicon is shown to behave as a glucose sensor that detects glucose with concentrations as low as 50μM.

  3. Immobilized humic substances and immobilized aggregates of humic substances as sorbent for solid phase extraction.

    Science.gov (United States)

    Erny, Guillaume L; Gonçalves, Bruna M; Esteves, Valdemar I

    2013-09-06

    In this work, humic substances (HS) immobilized, as a thin layer or as aggregates, on silica gel were tested as material for solid phase extraction. Some triazines (simazine, atrazine, therbutylazine, atrazine-desethyl-desisopropyl-2-hydroxy, ametryn and terbutryn), have been selected as test analytes due to their environmental importance and to span a large range of solubility and octanol/water partition coefficient (logP). The sorbent was obtained immobilizing a thin layer of HS via physisorption on a pre-coated silica gel with a cationic polymer (polybrene). While the sorbent could be used as it is, it was demonstrated that additional HS could be immobilized, via weak interactions, to form stable humic aggregates. However, while a higher quantity of HS could be immobilized, no significant differences were observed in the sorption parameters. This sorbent have been tested for solid phase extraction to concentrate triazines from aqueous matrixes. The sorbent demonstrated performances equivalent to commercial alternatives as a concentration factor between 50 and 200, depending on the type of triazines, was obtained. Moreover the low cost and the high flow rate of sample through the column allowed using high quantity of sorbent. The analytical procedure was tested with different matrixes including tap water, river water and estuarine water. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Enzyme immobilization and biocatalysis of polysiloxanes

    Science.gov (United States)

    Poojari, Yadagiri

    H, temperature, cross-link density, organic solvents and storage time using a hemoglobin assay. A notable finding was that free pepsin had zero activity in neutral buffer solution (pH 7) after incubation for 5 hours, while pepsin immobilized in the silicone elastomers was found to retain more than 70% of its maximum normalized activity. These results demonstrate that cross-linked poly(dimethylsiloxane) (PDMS) is a promising support material for the physical entrapment of hydrolytic enzymes such as pepsin. The Novozym-435 has been widely employed as a biocatalyst for esterification and transesterification of a variety of organic compounds including synthesis of polyesters and polylactones due to its high catalytic-efficiency and high thermal stability in organic media. However, the Novozym-435 was found to have poor mechanical stability and the enzyme was found to leach out from the resin into the organic media. In the present research work, efforts were made to solve the above two problems by chemical immobilization of CALB on surface modified porous silica gel particles. The surface of the porous silica gel particles was silanized using (gamma-Aminopropyl)triethoxysilane and then the CALB was chemically crosslinked onto the surface of the silica gel particles using glutaraldehyde. Although the thermal stability of the CALB immobilized silica gel particles was found to be lower compared to that of Novozym-435. The CALB immobilized silica gel particles showed higher enzymatic activity and higher mechanical stability compared to that of Novozym-435.

  5. Smectite clays as solid supports for immobilization of beta-glucosidase : Synthesis, characterization, and biochemical properties

    NARCIS (Netherlands)

    Serefoglou, Evangelia; Litina, Kiriaki; Gournis, Dimitrios; Kalogeris, Emmanuel; Tzialla, Aikaterini A.; Pavlidis, Ioannis V.; Stamatis, Haralambos; Maccallini, Enrico; Lubomska, Monika; Rudolf, Petra

    2008-01-01

    Nanomaterials as solid supports can improve the efficiency of immobilized enzymes by reducing diffusional limitation as well as by increasing the surface area per mass unit and therefore improving enzyme loading. In this work, beta-glucosidase from almonds was immobilized on two smectite nanoclays.

  6. An immobilization antigen gene of the fish-parasitic protozoan Ichthyophthirius multifiliis strain ARS-6

    Science.gov (United States)

    Ichthyophthirius multifiliis (Ich) is a severe fish parasite that causes ‘white spot’ disease in many freshwater fish and leads to high mortality. The antigens on the parasite surface are involved in the antibody-mediated immobilization and hence designated as immobilization antigens (i-antigens). ...

  7. High-level-waste immobilization

    International Nuclear Information System (INIS)

    Crandall, J.L.

    1982-01-01

    Analysis of risks, environmental effects, process feasibility, and costs for disposal of immobilized high-level wastes in geologic repositories indicates that the disposal system safety has a low sensitivity to the choice of the waste disposal form

  8. Graphene immobilized enzyme/polyethersulfone mixed matrix membrane: Enhanced antibacterial, permeable and mechanical properties

    International Nuclear Information System (INIS)

    Duan, Linlin; Wang, Yuanming; Zhang, Yatao; Liu, Jindun

    2015-01-01

    Graphical abstract: - Highlights: • Lysozyme was immobilized on the surface of graphene oxide (GO) and reduced GO (RGO). • The novel hybrid membranes based on lysozyme and graphene were fabricated firstly. • These membranes showed good antibacterial and mechanical performance. - Abstract: Enzyme immobilization has been developed to address lots of issues of free enzyme, such as instability, low activity and difficult to retain. In this study, graphene was used as an ideal carrier for lysozyme immobilization, including graphene oxide (GO) immobilized lysozyme (GO-Ly) and chemically reduced graphene oxide (CRGO) immobilized lysozyme (CRGO-Ly). Herein, lysozyme as a bio-antibacterial agent has excellent antibacterial performance and the products of its catalysis are safety and nontoxic. Then the immobilized lysozyme materials were blended into polyethersulfone (PES) casting solution to prepare PES ultrafiltration membrane via phase inversion method. GO and CRGO were characterized by Fourier transform infrared spectroscopy (FTIR), Ultraviolet–visible spectrum (UV), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and the immobilized lysozyme composites were observed by fluorescent microscopy. The results revealed that GO and CRGO were successfully synthesized and lysozyme was immobilized on their surfaces. The morphology, hydrophilicity, mechanical properties, separation properties and antibacterial activity of the hybrid membranes were characterized in detail. The hydrophilicity, water flux and mechanical strength of the hybrid membranes were significantly enhanced after adding the immobilized lysozyme. In the antibacterial experiment, the hybrid membranes exhibited an effective antibacterial performance against Escherichia coli (E. coli).

  9. Immobilized enzymes in blood plasma exchangers via radiation grafting

    Science.gov (United States)

    Gombotz, Wayne; Hoffman, Allan; Schmer, Gottfried; Uenoyama, Satoshi

    The enzyme asparaginase was immobilized onto a porous hollow polypropylene (PP) fiber blood plasma exchange device for the treatment of acute lymphocytic leukemia. The devices were first radiation grafted with polymethacrylic acid (poly(MAAc)). This introduces carboxyl groups onto the surface of the fibers. Several variables were studied in the grafting reaction including the effects of solvent type and monomer concentration. The carboxyl groups were activated with N-hydroxy succinimide (NHS) using carbodiimide chemistry. Asparaginase was then covalently immobilized on the activated surfaces. Quantitative relationships were found relating the percent graft to the amount of immobilized enzyme which was active. The enzyme reactor was tested both in vitro and in vivo using a sheep as an animal model.

  10. Characterization of immobilization methods of antiviral antibodies in serum for electrochemical biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Huy, Tran Quang, E-mail: huytq@nihe.org.vn [National Institute of Hygiene and Epidemiology (NIHE), No1 Yersin St., Hanoi (Viet Nam); International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No1 Dai Co Viet, Hanoi (Viet Nam); Hanh, Nguyen Thi Hong; Van Chung, Pham; Anh, Dang Duc; Nga, Phan Thi [National Institute of Hygiene and Epidemiology (NIHE), No1 Yersin St., Hanoi (Viet Nam); Tuan, Mai Anh, E-mail: tuanma-itims@mail.hut.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No1 Dai Co Viet, Hanoi (Viet Nam)

    2011-06-01

    In this paper, we describes different methods to immobilize Japanese encephalitis virus (JEV) antibodies in human serum onto the interdigitated surface of a microelectrode sensor for optimizing electrochemical detection: (1) direct covalent binding to the silanized surface, (2) binding to the silanized surface via a cross-linker of glutaraldehyde (GA), (3) binding to glutaraldehyde/silanized surface via goat anti-human IgG polyclonal antibody and (4) binding to glutaraldehyde/silanized surface via protein A (PrA). Field emission scanning electron microscopy, Fourier transform infrared spectrometry, and fluorescence microscopy are used to verify the characteristics of antibodies on the interdigitated surface after the serum antibodies immobilization. The analyzed results indicate that the use of protein A is an effective choice for immobilization and orientation of antibodies in serum for electrochemical biosensors. This study provides an advantageous immobilization method of serum containing antiviral antibodies to develop electrochemical biosensors for preliminary screening of viruses in clinical samples from outbreaks.

  11. Synchronous scattering and diffraction from gold nanotextured surfaces with structure factors

    Science.gov (United States)

    Gu, Min-Jhong; Lee, Ming-Tsang; Huang, Chien-Hsun; Wu, Chi-Chun; Chen, Yu-Bin

    2018-05-01

    Synchronous scattering and diffraction were demonstrated using reflectance from gold nanotextured surfaces at oblique (θi = 15° and 60°) incidence of wavelength λ = 405 nm. Two samples of unique auto-correlation functions were cost-effectively fabricated. Multiple structure factors of their profiles were confirmed with Fourier expansions. Bi-directional reflectance function (BRDF) from these samples provided experimental proofs. On the other hand, standard deviation of height and unique auto-correlation function of each sample were used to generate surfaces numerically. Comparing their BRDF with those of totally random rough surfaces further suggested that structure factors in profile could reduce specular reflection more than totally random roughness.

  12. Surface functionalization of nanoporous alumina with bone morphogenetic protein 2 for inducing osteogenic differentiation of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Song, Yuanhui; Ju, Yang; Morita, Yasuyuki; Xu, Baiyao; Song, Guanbin

    2014-01-01

    Many studies have demonstrated the possibility to regulate cellular behavior by manipulating the specific characteristics of biomaterials including the physical features and chemical properties. To investigate the synergistic effect of chemical factors and surface topography on the growth behavior of mesenchymal stem cells (MSCs), bone morphorgenic protein 2 (BMP2) was immobilized onto porous alumina substrates with different pore sizes. The BMP2-immobilized alumina substrates were characterized with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Growth behavior and osteogenic differentiation of MSCs cultured on the different substrates were investigated. Cell adhesion and morphological changes were observed with SEM, and the results showed that the BMP2-immobilized alumina substrate was able to promote adhesion and spreading of MSCs. MTT assay and immunofluorescence staining of integrin β1 revealed that the BMP2-immobilized alumina substrates were favorable for cell growth. To evaluate the differentiation of MSCs, osteoblastic differentiation markers, such as alkaline phosphatase (ALP) activity and mineralization, were investigated. Compared with those of untreated alumina substrates, significantly higher ALP activities and mineralization were detected in cells cultured on BMP2-immobilized alumina substrates. The results suggested that surface functionalization of nanoporous alumina substrates with BMP2 was beneficial for cell growth and osteogenic differentiation. With the approach of immobilizing growth factors onto material substrates, it provided a new insight to exploit novel biofunctional materials for tissue engineering. - Highlights: • BMP2 was immobilized onto nanoporous alumina substrates with different pore sizes. • BMP2-immobilized substrates were able to promote adhesion and spreading of MSCs. • BMP2-immobilized substrates were favorable for cell growth of MSCs. • BMP2-immobilized substrates promoted osteogenic

  13. Biosorption of americium-241 by immobilized Rhizopus arrihizus

    International Nuclear Information System (INIS)

    Liao Jiali; Yang Yuanyou; Luo Shunzhong; Liu Ning; Jin Jiannan; Zhang Taiming; Zhao Pengji

    2004-01-01

    Rhizopus arrihizus (R. arrihizus), a fungus, which in previous experiments had shown encouraging ability to remove 241 Am from solutions, was immobilized by calcium alginate and other reagents. The various factors affecting 241 Am biosorption by the immobilized R. arrihizus were investigated. The results showed that not only can immobilized R. arrihizus adsorb 241 Am as efficiently as free R. arrihizus, but that also can be used repeatedly or continuously. The biosorption equilibrium was achieved within 2 h, and more than 94% of 241 Am was removed from 241 Am solutions of 1.08 MBq/l by immobilized R. arrihizu in the pH range 1-7. Temperature did not affect the adsorption on immobilized R. arrihizus in the range 15-45 deg. C. After repeated adsorption for 8 times, the immobilized R. arrihizus still adsorbed more than 97% of 241 Am. At this time, the total adsorption of 241 Am was more than 88.6 KBq/g, and had not yet reached saturation. Ninety-five percent of the adsorbed 241 Am was desorbed by saturated EDTA solution and 98% by 2 mol/l HNO 3

  14. Radiation exchange factors between specular inner surfaces of a rectangular enclosure such as transplant production unit

    International Nuclear Information System (INIS)

    Abdel-Ghany, Ahmed M.; Kozai, Toyoki

    2006-01-01

    General mathematical relations are presented for the specular exchange factors, F S , of diffuse radiation exchange between the inner surfaces of a rectangular enclosure. Three of these surfaces are specular reflectors, diffuse emitters and the fourth surface is a diffuse reflector, diffuse emitter. This enclosure can be used as a transplant production unit with artificial lighting for electric energy saving purposes. An image system and the crossed string method are used to derive these relations. The resulting expressions are conceptually simple and similar to the commonly known expressions of the exchange factors between diffuse surfaces, F. The accuracy of the presented F S relations was examined for different numbers of multiple reflections, N, on the specular surfaces and for different aspect ratios (ratio of the width, w to the height, h). The results proved that the relations are accurate and strongly satisfy the well-known relation of the radiation exchange between enclosure surfaces and satisfy the reciprocity relation. For any aspect ratio, considering N of 150 between highly reflective surfaces (ρ = 0.99) is sufficient to estimate the F S factors without any possible error. Using specular reflecting surfaces in such cases significantly reduces the electric energy consumption used for lighting

  15. Phospholipid-sepiolite biomimetic interfaces for the immobilization of enzymes.

    Science.gov (United States)

    Wicklein, Bernd; Darder, Margarita; Aranda, Pilar; Ruiz-Hitzky, Eduardo

    2011-11-01

    Biomimetic interfaces based on phosphatidylcholine (PC) assembled to the natural silicate sepiolite were prepared for the stable immobilization of the urease and cholesterol oxidase enzymes. This is an important issue in practical advanced applications such as biocatalysis or biosensing. The supported lipid bilayer (BL-PC), prepared from PC adsorption, was used for immobilization of enzymes and the resulting biomimetic systems were compared to several other supported layers including a lipid monolayer (ML-PC), a mixed phosphatidylcholine/octyl-galactoside layer (PC-OGal), a cetyltrimethylammonium monolayer (CTA), and also to the bare sepiolite surface. Interfacial characteristics of these layers were investigated with a focus on layer packing density, hydrophilicity/hydrophobicity, and surface charge, which are being considered as key points for enzyme immobilization and stabilization of their biological activity. Cytoplasmic urease and membrane-bound cholesterol oxidase, which served as model enzymes, were immobilized on the different PC-based hybrid materials to probe their biomimetic character. Enzymatic activity was assessed by cyclic voltammetry and UV-vis spectrophotometry. The resulting enzyme/bio-organoclay hybrids were applied as active phase of a voltammetric urea biosensor and cholesterol bioreactor, respectively. Urease supported on sepiolite/BL-PC proved to maintain its enzymatic activity over several months while immobilized cholesterol oxidase demonstrated high reusability as biocatalyst. The results emphasize the good preservation of bioactivity due to the accommodation of the enzymatic system within the biomimetic lipid interface on sepiolite.

  16. Stress intensity factor analyses of surface cracks in three-dimensional structures

    International Nuclear Information System (INIS)

    Miyazaki, Noriyuki; Shibata, Katsuyuki; Watanabe, Takayuki; Tagata, Kazunori.

    1983-11-01

    The stress intensity factor analyses of surface cracks in various three-dimensional structures were performed using the finite element computer program EPAS-J1. The results obtained by EPAS-J1 were compared with other finite element solutions or results obtained by the simplified estimation methods. Among the simplified estimation methods, the equations proposed by Newman and Raju give the distributions of the stress intensity factor along a crack front, which were compared with the result obtained by EPAS-J1. It was confirmed by comparing the results that EPAS-J1 gives reasonable stress intensity factors of surface cracks in three-dimensional structures. (author)

  17. Combinational Effect of Cell Adhesion Biomolecules and Their Immobilized Polymer Property to Enhance Cell-Selective Adhesion

    Directory of Open Access Journals (Sweden)

    Rio Kurimoto

    2016-01-01

    Full Text Available Although surface immobilization of medical devices with bioactive molecules is one of the most widely used strategies to improve biocompatibility, the physicochemical properties of the biomaterials significantly impact the activity of the immobilized molecules. Herein we investigate the combinational effects of cell-selective biomolecules and the hydrophobicity/hydrophilicity of the polymeric substrate on selective adhesion of endothelial cells (ECs, fibroblasts (FBs, and smooth muscle cells (SMCs. To control the polymeric substrate, biomolecules are immobilized on thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (poly(NIPAAm-co-CIPAAm-grafted glass surfaces. By switching the molecular conformation of the biomolecule-immobilized polymers, the cell-selective adhesion performances are evaluated. In case of RGDS (Arg-Gly-Asp-Ser peptide-immobilized surfaces, all cell types adhere well regardless of the surface hydrophobicity. On the other hand, a tri-Arg-immobilized surface exhibits FB-selectivity when the surface is hydrophilic. Additionally, a tri-Ile-immobilized surface exhibits EC-selective cell adhesion when the surface is hydrophobic. We believe that the proposed concept, which is used to investigate the biomolecule-immobilized surface combination, is important to produce new biomaterials, which are highly demanded for medical implants and tissue engineering.

  18. The dependence of the nuclear charge form factor on short range correlations and surface fluctuation effects

    International Nuclear Information System (INIS)

    Massen, S. E.; Garistov, V. P.; Grypeos, M. E.

    1996-01-01

    The effects of nuclear surface fluctuations on harmonic oscillator elastic charge form factor of light nuclei are investigated, simultaneously approximating the short-range correlations through a Jastrow correlation factor. Inclusion of the surface fluctuation effects within this description, by truncating the cluster expansion at the two-body part, is found to improve somewhat the fit to the elastic charge form-factor of 16 O and 40 Ca. However, the convergence of the cluster expansion is expected to deteriorate. An additional finding is that surface-fluctuation correlations produce a drastic change in the asymptotic behaviour of the point-proton form-factor, which now falls off quite slowly (i.e. as const.q -4 ) at large values of the momentum transfer q

  19. Refined toric branes, surface operators and factorization of generalized Macdonald polynomials

    Science.gov (United States)

    Zenkevich, Yegor

    2017-09-01

    We find new universal factorization identities for generalized Macdonald polynomials on the topological locus. We prove the identities (which include all previously known forumlas of this kind) using factorization identities for matrix model averages, which are themselves consequences of Ding-Iohara-Miki constraints. Factorized expressions for generalized Macdonald polynomials are identified with refined topological string amplitudes containing a toric brane on an intermediate preferred leg, surface operators in gauge theory and certain degenerate CFT vertex operators.

  20. Hybrid surface platform for the simultaneous detection of proteins and DNA using a surface plasmon resonance (SPR) imaging sensor

    Czech Academy of Sciences Publication Activity Database

    Homola, Jiří; Piliarik, Marek; Ladd, J.; Taylor, A.; Shaoyi, J.

    2008-01-01

    Roč. 80, č. 11 (2008), s. 4231-4236 ISSN 0003-2700 R&D Projects: GA AV ČR KAN200670701 Institutional research plan: CEZ:AV0Z20670512 Keywords : Surface plasmon resonance imaging * DNA-directed immobilization * protein array Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 5.712, year: 2008

  1. Immobilization Techniques for Microarray: Challenges and Applications

    Directory of Open Access Journals (Sweden)

    Satish Balasaheb Nimse

    2014-11-01

    Full Text Available The highly programmable positioning of molecules (biomolecules, nanoparticles, nanobeads, nanocomposites materials on surfaces has potential applications in the fields of biosensors, biomolecular electronics, and nanodevices. However, the conventional techniques including self-assembled monolayers fail to position the molecules on the nanometer scale to produce highly organized monolayers on the surface. The present article elaborates different techniques for the immobilization of the biomolecules on the surface to produce microarrays and their diagnostic applications. The advantages and the drawbacks of various methods are compared. This article also sheds light on the applications of the different technologies for the detection and discrimination of viral/bacterial genotypes and the detection of the biomarkers. A brief survey with 115 references covering the last 10 years on the biological applications of microarrays in various fields is also provided.

  2. An orientation analysis method for protein immobilized on quantum dot particles

    Energy Technology Data Exchange (ETDEWEB)

    Aoyagi, Satoka, E-mail: aoyagi@life.shimane-u.ac.jp [Faculty of Life and Environmental Science, Shimane University, 1060 Matsue-shi, Shimane 690-8504 (Japan); Inoue, Masae [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)

    2009-11-30

    The evaluation of orientation of biomolecules immobilized on nanodevices is crucial for the development of high performance devices. Such analysis requires ultra high sensitivity so as to be able to detect less than one molecular layer on a device. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has sufficient sensitivity to evaluate the uppermost surface structure of a single molecular layer. The objective of this study is to develop an orientation analysis method for proteins immobilized on nanomaterials such as quantum dot particles, and to evaluate the orientation of streptavidin immobilized on quantum dot particles by means of TOF-SIMS. In order to detect fragment ions specific to the protein surface, a monoatomic primary ion source (Ga{sup +}) and a cluster ion source (Au{sub 3}{sup +}) were employed. Streptavidin-immobilized quantum dot particles were immobilized on aminosilanized ITO glass plates at amino groups by covalent bonding. The reference samples streptavidin directly immobilized on ITO plates were also prepared. All samples were dried with a freeze dryer before TOF-SIMS measurement. The positive secondary ion spectra of each sample were obtained using TOF-SIMS with Ga{sup +} and Au{sub 3}{sup +}, respectively, and then they were compared so as to characterize each sample and detect the surface structure of the streptavidin immobilized with the biotin-immobilized quantum dots. The chemical structures of the upper surface of the streptavidin molecules immobilized on the quantum dot particles were evaluated with TOF-SIMS spectra analysis. The indicated surface side of the streptavidin molecules immobilized on the quantum dots includes the biotin binding site.

  3. Optimizing Immobilized Enzyme Performance in Cell-Free Environments to Produce Liquid Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Belfort, Georges [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemical and Biological Engineering; Grimaldi, Joseph J. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemical and Biological Engineering

    2015-01-27

    Limitations on biofuel production using cell culture (Escherichia coli, Clostridium, Saccharomyces cerevisiae, brown microalgae, blue-green algae and others) include low product (alcohol) concentrations (≤0.2 vol%) due to feedback inhibition, instability of cells, and lack of economical product recovery processes. To overcome these challenges, an alternate simplified biofuel production scheme was tested based on a cell-free immobilized enzyme system. Using this cell free system, we were able to obtain about 2.6 times higher concentrations of iso-butanol using our non-optimized system as compared with live cell systems. This process involved two steps: (i) converts acid to aldehyde using keto-acid decarboxylase (KdcA), and (ii) produces alcohol from aldehyde using alcohol dehydrogenase (ADH) with a cofactor (NADH) conversion from inexpensive formate using a third enzyme, formate dehydrogenase (FDH). To increase stability and conversion efficiency with easy separations, the first two enzymes were immobilized onto methacrylate resin. Fusion proteins of labile KdcA (fKdcA) were expressed to stabilize the covalently immobilized KdcA. Covalently immobilized ADH exhibited long-term stability and efficient conversion of aldehyde to alcohol over multiple batch cycles without fusions. High conversion rates and low protein leaching were achieved by covalent immobilization of enzymes on methacrylate resin. The complete reaction scheme was demonstrated by immobilizing both ADH and fKdcA and using FDH free in solution. The new system without in situ removal of isobutanol achieved a 55% conversion of ketoisovaleric acid to isobutanol at a concentration of 0.5 % (v/v). Further increases in titer will require continuous removal of the isobutanol using our novel brush membrane system that exhibits a 1.5 fold increase in the separation factor of isobutanol from water versus that obtained for commercial silicone rubber membranes. These bio-inspired brush membranes are based on the

  4. Status of plutonium ceramic immobilization processes and immobilization forms

    Energy Technology Data Exchange (ETDEWEB)

    Ebbinghaus, B.B.; Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (United States); Vance, E.R.; Jostsons, A. [Australian Nuclear Science and Technology Organization, Menai (Australia)] [and others

    1996-05-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  5. Status of plutonium ceramic immobilization processes and immobilization forms

    International Nuclear Information System (INIS)

    Ebbinghaus, B.B.; Van Konynenburg, R.A.; Vance, E.R.; Jostsons, A.

    1996-01-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R ampersand D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi 2 O 7 ), the desired actinide host phase, with lesser amounts of hollandite (BaAl 2 Ti 6 O 16 ) and rutile (TiO 2 ). Alternative actinide host phases are also being considered. These include pyrochlore (Gd 2 Ti 2 O 7 ), zircon (ZrSiO 4 ), and monazite (CePO 4 ), to name a few of the most promising. R ampersand D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO 2 powder, cold press and sinter fabrication methods, and immobilization form formulation issues

  6. SU-E-T-577: Obliquity Factor and Surface Dose in Proton Beam Therapy

    International Nuclear Information System (INIS)

    Das, I; Andersen, A; Coutinho, L

    2015-01-01

    Purpose: The advantage of lower skin dose in proton beam may be diminished creating radiation related sequalae usually seen with photon and electron beams. This study evaluates the surface dose as a complex function of beam parameters but more importantly the effect of beam angle. Methods: Surface dose in proton beam depends on the beam energy, source to surface distance, the air gap between snout and surface, field size, material thickness in front of surface, atomic number of the medium, beam angle and type of nozzle (ie double scattering, (DS), uniform scanning (US) or pencil beam scanning (PBS). Obliquity factor (OF) is defined as ratio of surface dose in 0° to beam angle Θ. Measurements were made in water phantom at various beam angles using very small microdiamond that has shown favorable beam characteristics for high, medium and low proton energy. Depth dose measurements were performed in the central axis of the beam in each respective gantry angle. Results: It is observed that surface dose is energy dependent but more predominantly on the SOBP. It is found that as SSD increases, surface dose decreases. In general, SSD, and air gap has limited impact in clinical proton range. High energy has higher surface dose and so the beam angle. The OF rises with beam angle. Compared to OF of 1.0 at 0° beam angle, the value is 1.5, 1.6, 1,7 for small, medium and large range respectively for 60 degree angle. Conclusion: It is advised that just like range and SOBP, surface dose should be clearly understood and a method to reduce the surface dose should be employed. Obliquity factor is a critical parameter that should be accounted in proton beam therapy and a perpendicular beam should be used to reduce surface dose

  7. Immobilization of bioactive fibroblast growth factor-2 into cubic proteinous microcrystals (Bombyx mori cypovirus polyhedra) that are insoluble in a physiological cellular environment.

    Science.gov (United States)

    Mori, Hajime; Shukunami, Chisa; Furuyama, Akiko; Notsu, Hiroyuki; Nishizaki, Yuriko; Hiraki, Yuji

    2007-06-08

    The supramolecular architecture of the extracellular matrix and the disposition of its specific accessory molecules give rise to variable heterotopic signaling cues for single cells. Here we have described the successful occlusion of human fibroblast growth factor-2 (FGF-2) into the cubic inclusion bodies (FGF-2 polyhedra) of the Bombyx mori cytoplasmic polyhedrosis virus (BmCPV). The polyhedra are proteinous cubic crystals of several microns in size that are insoluble in the extracellular milieu. Purified FGF-2 polyhedra were found to stimulate proliferation and phosphorylation of p44/p42 mitogen-activated protein kinase in cultured fibroblasts. Moreover, cellular responses were blocked by a synthetic inhibitor of the FGF signaling pathway, SU5402, suggesting that FGF-2 polyhedra indeed act through FGF receptors. Furthermore, FGF-2 polyhedra retained potent growth stimulatory properties even after desiccation. We have demonstrated that BmCPV polyhedra microcrystals that occlude extracellular signaling proteins are a novel and versatile tool that can be employed to analyze cellular behavior at the single cell level.

  8. A response calculus for immobilized T cell receptor ligands

    DEFF Research Database (Denmark)

    Andersen, P S; Menné, C; Mariuzza, R A

    2001-01-01

    determine the level of T cell activation. When fitted to T cell responses against purified ligands immobilized on plastic surfaces, the 2D-affinity model adequately simulated changes in cellular activation as a result of varying ligand affinity and ligand density. These observations further demonstrated...

  9. Stepwise Reduction of Immobilized Mono layer Graphene Oxides

    DEFF Research Database (Denmark)

    Petersen, Søren; He, Yudong; Lang, Jiang

    2013-01-01

    to the pronounced aggregation that accompanies deoxygenation of GO in solution. Surface immobilization of monolayered graphene oxide (mGO) in Langmuir-Blodgett (LB) films was investigated as a method to circumvent this problem. Two types of LB films with different density of mGO flakes were prepared, i.e., diluted...

  10. Calculated dose factors for the radiosensitive tissues in bone irradiated by surface-deposited radionuclides

    International Nuclear Information System (INIS)

    Spiers, F.W.; Whitwell, J.R.; Beddoe, A.H.

    1978-01-01

    The method of calculating dose factors for the haemopoietic marrow and endosteal tissues in human trabecular bone, used by Whitwell and Spiers for volume-seeking radionuclides, has been developed for the case of radionuclides which are deposited as very thin layers on bone surfaces. The Monte Carlo method is again used, but modifications to the computer program are made to allow for a surface rather than a volume source of particle emission. The principal change is the introduction of a surface-orientation factor which is shown to have a value of approximately 2, varying slightly with bone structure. Results are given for β-emitting radionuclides ranging from 171 Tm(anti Esub(β) = 0.025 MeV) to 90 Y(anti Esub(β) = 0.93 MeV), and also for the α-emitter 239 Pu. It is shown that where the particle ranges are short compared with the dimensions of the bone structures the dose factors for the surface seekers are much greater than those for the volume seekers. For long range particles the dose factors for surface- and volume-seeking radionuclides converge. Comparisons are given relating the dose factors calculated in this paper on the basis of measured bone structures to those of other workers based on single plane geometry. (author)

  11. Performance Enhancements to the Hanford Waste Treatment and Immobilization Plant Low-Activity Waste Vitrification System

    International Nuclear Information System (INIS)

    Hamel, W. F.; Gerdes, K.; Holton, L. K.; Pegg, I.L.; Bowan, B.W.

    2006-01-01

    The U.S Department of Energy Office of River Protection (DOE-ORP) is constructing a Waste Treatment and Immobilization Plant (WTP) for the treatment and vitrification of underground tank wastes stored at the Hanford Site in Washington State. The WTP comprises four major facilities: a pretreatment facility to separate the tank waste into high level waste (HLW) and low-activity waste (LAW) process streams, a HLW vitrification facility to immobilize the HLW fraction; a LAW vitrification facility to immobilize the LAW fraction, and an analytical laboratory to support the operations of all four treatment facilities. DOE has established strategic objectives to optimize the performance of the WTP facilities and the LAW and HLW waste forms to reduce the overall schedule and cost for treatment and vitrification of the Hanford tank wastes. This strategy has been implemented by establishing performance expectations in the WTP contract for the facilities and waste forms. In addition, DOE, as owner-operator of the WTP facilities, continues to evaluate 1) the design, to determine the potential for performance above the requirements specified in the WTP contract; and 2) improvements in production of the LAW and HLW waste forms. This paper reports recent progress directed at improving production of the LAW waste form. DOE's initial assessment, which is based on the work reported in this paper, is that the treatment rate of the WTP LAW vitrification facility can be increased by a factor of 2 to 4 with a combination of revised glass formulations, modest increases in melter glass operating temperatures, and a second-generation LAW melter with a larger surface area. Implementing these improvements in the LAW waste immobilization capability can benefit the LAW treatment mission by reducing the cost of waste treatment. (authors)

  12. Application of Molecular Imprinted Magnetic Fe3O4@SiO2 Nanoparticles for Selective Immobilization of Cellulase.

    Science.gov (United States)

    Tao, Qing-Lan; Li, Yue; Shi, Ying; Liu, Rui-Jiang; Zhang, Ye-Wang; Guo, Jianyong

    2016-06-01

    Magnetic Fe3O4@SiO2 nanoparticles were prepared with molecular imprinting method using cellulase as the template. And the surface of the nanoparticles was chemically modified with arginine. The prepared nanoparticles were used as support for specific immobilization of cellulase. SDS-PAGE results indicated that the adsorption of cellulase onto the modified imprinted nanoparticles was selective. The immobilization yield and efficiency were obtained more than 70% after the optimization. Characterization of the immobilized cellulase revealed that the immobilization didn't change the optimal pH and temperature. The half-life of the immobilized cellulase was 2-fold higher than that of the free enzyme at 50 degrees C. After 7 cycles reusing, the immobilized enzyme still retained 77% of the original activity. These results suggest that the prepared imprinted nanoparticles have the potential industrial applications for the purification or immobilization of enzymes.

  13. Modification of the ASME code z-factor for circumferential surface crack in nuclear ferritic pipings

    International Nuclear Information System (INIS)

    Choi, Young Hwan; Chung, Yon Ki; Koh, Wan Young; Lee, Joung Bae

    1996-01-01

    The purpose of this paper is to modify the ASME Code Z-Factor, which is used in the evaluation of circumferential surface crack in nuclear ferritic pipings. The ASME Code Z-Factor is a load multiplier to compensate plastic load with elasto-plastic load. The current ASME Code Z-Factor underestimates pipe maximum load. In this study, the original SC. TNP method is modified first because the original SC. TNP method has a problem that the maximum allowable load predicted from the original SC. TNP method is slightly higher than that measured from the experiment. Then the new Z-Factor is developed using the modified SC. TNP method. The desirability of both the modified SC. TNP method and the new Z-Factor is examined using the experimental results for the circumferential surface crack in pipings. The results show that (1) the modified SC. TNP method is good for predicting the circumferential surface crack behavior in pipings, and (2) the Z-Factor obtained from the modified SC. TNP method well predicts the behavior of circumferential surface crack in ferritic pipings. 30 refs., 13 figs., 4 tabs. (author)

  14. Analysis of alternatives for immobilized low activity waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Burbank, D.A.

    1997-10-28

    This report presents a study of alternative disposal system architectures and implementation strategies to provide onsite near-surface disposal capacity to receive the immobilized low-activity waste produced by the private vendors. The analysis shows that a flexible unit strategy that provides a suite of design solutions tailored to the characteristics of the immobilized low-activity waste will provide a disposal system that best meets the program goals of reducing the environmental, health, and safety impacts; meeting the schedule milestones; and minimizing the life-cycle cost of the program.

  15. Analysis of alternatives for immobilized low-activity waste disposal

    International Nuclear Information System (INIS)

    Burbank, D.A.

    1997-01-01

    This report presents a study of alternative disposal system architectures and implementation strategies to provide onsite near-surface disposal capacity to receive the immobilized low-activity waste produced by the private vendors. The analysis shows that a flexible unit strategy that provides a suite of design solutions tailored to the characteristics of the immobilized low-activity waste will provide a disposal system that best meets the program goals of reducing the environmental, health, and safety impacts; meeting the schedule milestones; and minimizing the life-cycle cost of the program

  16. Immobilization needs and technology programs

    International Nuclear Information System (INIS)

    Gray, L.W.; Kan, T.; Shaw, H.; Armantrout, G.

    1995-01-01

    In the aftermath of the Cold War, the US and Russia agreed to large reductions in nuclear weapons. To aid in the selection of long-term management options, DOE has undertaken a multifaceted study to select options for storage and disposition of plutonium in keeping with US policy that plutonium must be subjected to the highest standards of safety, security, and accountability. One alternative being considered is immobilization. To arrive at a suitable immobilization form, we first reviewed published information on high-level waste immobilization technologies and identified 72 possible plutonium immobilization forms to be prescreened. Surviving forms were further screened using multi-attribute utility analysis to determine the most promising technology families. Promising immobilization families were further evaluated to identify chemical, engineering, environmental, safety, and health problems that remain to be solved prior to making technical decisions as to the viability of using the form for long- term disposition of plutonium. From this evaluation, a detailed research and development plan has been developed to provide answers to these remaining questions

  17. Electrode-immobilized compounds through γ radiation

    International Nuclear Information System (INIS)

    De Castro, E.S.

    1983-01-01

    Chemically Modified Electrodes (CMEs) are used as substrates in heterogeneous catalysis and as sensors. This work demonstrates a new strategy for immobilizing polyelectrolytes and electroactive agents on electrode surfaces. The success of this method lies in cross-linking water soluble polymer chains through the ionizing radiation of γ emissions from a 60 Co source. Cross-linking can create a continuous network out of the polymer macromolecules which then makes the network insoluble on the electrode surface. Bonds between the network and the substrate are also possible. Redox species mixed with the polymer network and irradiated become part of the insoluble network, and are permanently attached. The use of γ radiation to make electrochemical sensors is demonstrated. The immobilized network poly[diallyl dimethyl ammonium chloride] (DDAC) is placed in a solution of potassium ferricyanide and ionicly exchanges the anion into the network. An electroactive network is created from irradiating a mixture of DDAC and 2,6-dichlorophenolindophenol (DCIP). Using the amount of electroactive DCIP remaining in the film as the optimization parameter, variables such as polymer:DCIP ratio, film thickness, and dosage employed are shown to be relevant

  18. Magnetic bead cellulose as a suitable support for immobilization of .alpha.-chymotrypsin

    Czech Academy of Sciences Publication Activity Database

    Přikryl, P.; Lenfeld, Jiří; Horák, Daniel; Tichá, M.; Kučerová, Z.

    2012-01-01

    Roč. 168, č. 2 (2012), s. 295-305 ISSN 0273-2289 R&D Projects: GA ČR GA203/09/0857 Institutional research plan: CEZ:AV0Z40500505 Keywords : enzyme immobilization * human gastric juice * immobilized α-chymotrypsin Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.893, year: 2012

  19. Immobilization of cellulase by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1983-01-01

    Immobilization of cellulase by radiation polymerization at low temperatures was studied. The enzymatic activity of immobilized cellulase pellets varied with the monomer, enzyme concentration, and the thickness of immobilized cellulase pellets. The optimum monomer concentration in the immobilization of cellulase was 30-50% at the pellet thickness of 1.0 mm, in which the enzymatic activity was 50%. The enzymatic activity of immobilized cellulase pellets was examined using various substrates such as cellobiose, carboxymethylcellulose, and paper pretreated by radiation. It was found that irradiated paper can be hydrolyzed by immobilized cellulase pellets. (author)

  20. Binary polypeptide system for permanent and oriented protein immobilization

    Directory of Open Access Journals (Sweden)

    Bailes Julian

    2010-05-01

    Full Text Available Abstract Background Many techniques in molecular biology, clinical diagnostics and biotechnology rely on binary affinity tags. The existing tags are based on either small molecules (e.g., biotin/streptavidin or glutathione/GST or peptide tags (FLAG, Myc, HA, Strep-tag and His-tag. Among these, the biotin-streptavidin system is most popular due to the nearly irreversible interaction of biotin with the tetrameric protein, streptavidin. The major drawback of the stable biotin-streptavidin system, however, is that neither of the two tags can be added to a protein of interest via recombinant means (except for the Strep-tag case leading to the requirement for chemical coupling. Results Here we report a new immobilization system which utilizes two monomeric polypeptides which self-assemble to produce non-covalent yet nearly irreversible complex which is stable in strong detergents, chaotropic agents, as well as in acids and alkali. Our system is based on the core region of the tetra-helical bundle known as the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex. This irreversible protein attachment system (IPAS uses either a shortened syntaxin helix and fused SNAP25-synaptobrevin or a fused syntaxin-synaptobrevin and SNAP25 allowing a two-component system suitable for recombinant protein tagging, capture and immobilization. We also show that IPAS is suitable for use with traditional beads and chromatography, planar surfaces and Biacore, gold nanoparticles and for protein-protein interaction in solution. Conclusions IPAS offers an alternative to chemical cross-linking, streptavidin-biotin system and to traditional peptide affinity tags and can be used for a wide range of applications in nanotechnology and molecular sciences.

  1. Growth factor delivery: How surface interactions modulate release in vitro and in vivo

    Science.gov (United States)

    King, William J.; Krebsbach, Paul H.

    2013-01-01

    Biomaterial scaffolds have been extensively used to deliver growth factors to induce new bone formation. The pharmacokinetics of growth factor delivery has been a critical regulator of their clinical success. This review will focus on the surface interactions that control the non-covalent incorporation of growth factors into scaffolds and the mechanisms that control growth factor release from clinically relevant biomaterials. We will focus on the delivery of recombinant human bone morphogenetic protein-2 from materials currently used in the clinical practice, but also suggest how general mechanisms that control growth factor incorporation and release delineated with this growth factor could extend to other systems. A better understanding of the changing mechanisms that control growth factor release during the different stages of preclinical development could instruct the development of future scaffolds for currently untreatable injuries and diseases. PMID:22433783

  2. Effect of non-uniform surface resistance on the quality factor of superconducting niobium cavity

    Science.gov (United States)

    Tan, Weiwei; Lu, Xiangyang; Yang, Ziqin; Zhao, Jifei; Yang, Deyu; Yang, Yujia

    2016-08-01

    The formula Rs = G /Q0 is commonly used in the calculation of the surface resistance of radio frequency niobium superconducting cavities. The applying of such equation is under the assumption that surface resistance is consistent over the cavity. However, the distribution of the magnetic field varies over the cavity. The magnetic field in the equator is much higher than that in the iris. According to Thermal Feedback Theory, it leads non-uniform distribution of the density of heat flux, which results in a different temperature distribution along the cavity inter surface. The BCS surface resistance, which depends largely on the temperature, is different in each local inner surface. In this paper, the effect of surface non-uniform resistance on the quality factor has been studied, through the calculation of Q0 in the original definition of it. The results show that it is necessary to consider the non-uniform distribution of magnetic field when the accelerating field is above 20 MV/m for TESLA cavities. Also, the effect of inhomogeneity of residual resistance on the quality factor is discussed. Its distribution barely affects the quality factor.

  3. Approaching Immobilization of Enzymes onto Open Porous Basotect®

    Directory of Open Access Journals (Sweden)

    Peter J. Allertz

    2017-11-01

    Full Text Available For the first time, commercial macroporous melamine formaldehyde foam Basotect® (BT was used as a basic carrier material for both adsorptive and covalent enzyme immobilization. In order to access inherent amino groups, the Basotect® surface was pretreated with hydrochloric acid. The resulting material revealed 6 nmol of superficial amino groups per milligram Basotect®. Different optimized strategies for tethering the laccase from Trametes versicolor and the lipase from Thermomyces lanuginosus onto the pre-treated Basotect® surface were studied. Particularly, for covalent immobilization, two different strategies were pursued: lipase was tethered via a cross-linking method using 1-ethyl-3-(3-dimethylaminopropylcarbodiimide, and laccase was bound after functionalizing Basotect® with hydrophilic copolymer poly(ethylene-alt-maleic anhydride (PEMA. Prior to laccase immobilization, the PEMA coating of Basotect® was verified by ATR-FTIR analysis. Subsequent quantification of available high-reactive PEMA anhydride moieties revealed an amount of 1028 ± 73 nmol per mg Basotect®. The surface-bound enzyme amounts were quantified as 4.1–5.8 μg per mg Basotect®. A theoretical surface-covered enzyme mass for the ideal case that an enzyme monolayer was immobilized onto the Basotect® surface was calculated and compared to the amount of adsorptive and covalently bound enzymes before and after treatment with SDS. Furthermore, the enzyme activities were determined for the different immobilization approaches, and the stability during storage over time and against sodium dodecyl sulfate treatment was monitored. Additionally, PEMA-BT-bound laccase was tested for the elimination of anthropogenic micropollutant bisphenol A from contaminated water in a cost-effective and environmentally-friendly way and resulted in a degradation rate higher than 80%.

  4. The glycoprotein Ib-IX-V complex contributes to tissue factor-independent thrombin generation by recombinant factor VIIa on the activated platelet surface

    NARCIS (Netherlands)

    Weeterings, Cees; de Groot, Philip G.; Adelmeijer, Jelle; Lisman, Ton

    2008-01-01

    Several lines of evidence suggest that recombinant factor VIIa (rFVIIa) is able to activate factor X on an activated platelet, in a tissue factor-independent manner. We hypothesized that, besides the anionic surface, a receptor on the activated platelet surface is involved in this process. Here, we

  5. Immobilization of cellulase on functionalized cobalt ferrite nanoparticles

    International Nuclear Information System (INIS)

    Bohara, Raghvendra Ashok; Thorat, Nanasaheb Devappa; Pawar, Shivaji Hariba

    2016-01-01

    Amine functionalized cobalt ferrite (AF-CoFe 2 O 4 ) magnetic nanoparticles (MNPs) were used for immobilization of cellulase enzyme via 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDS) and N-hydroxysuccinimide (NHS) coupling reaction. The structural, morphological and magnetic properties of AF-CoFe 2 O 4 were determined. TEM micrograph revealed a mean diameter of -8 nm and showed that the AF-CoFe 2 O 4 remain distinct with no significant change in size after binding with cellulase. Fourier transform infrared (FT-IR) spectroscopy confirmed the binding of cellulase to AF-CoFe 2 O 4 . The properties of immobilized cellulase were investigated by optimizing binding efficiency, pH, temperature and reusability. The results showed that the immobilized cellulase has higher thermal stability than free cellulase, which might be due to covalent interaction between cellulase and AF-CoFe 2 O 4 surface. The immobilized cellulase also showed good reusability after recovery. Therefore, AF-CoFe 2 O 4 MNPs can be considered as promising candidate for enzyme immobilization.

  6. Immobilization of cellulase on functionalized cobalt ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bohara, Raghvendra Ashok; Thorat, Nanasaheb Devappa; Pawar, Shivaji Hariba [Center for Interdisciplinary Research, D. Y. Patil University, Kolhapur (India)

    2016-01-15

    Amine functionalized cobalt ferrite (AF-CoFe{sub 2}O{sub 4}) magnetic nanoparticles (MNPs) were used for immobilization of cellulase enzyme via 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDS) and N-hydroxysuccinimide (NHS) coupling reaction. The structural, morphological and magnetic properties of AF-CoFe{sub 2}O{sub 4} were determined. TEM micrograph revealed a mean diameter of -8 nm and showed that the AF-CoFe{sub 2}O{sub 4} remain distinct with no significant change in size after binding with cellulase. Fourier transform infrared (FT-IR) spectroscopy confirmed the binding of cellulase to AF-CoFe{sub 2}O{sub 4}. The properties of immobilized cellulase were investigated by optimizing binding efficiency, pH, temperature and reusability. The results showed that the immobilized cellulase has higher thermal stability than free cellulase, which might be due to covalent interaction between cellulase and AF-CoFe{sub 2}O{sub 4} surface. The immobilized cellulase also showed good reusability after recovery. Therefore, AF-CoFe{sub 2}O{sub 4} MNPs can be considered as promising candidate for enzyme immobilization.

  7. Gamma-Ray Bursts and Relativistic Shells: The Surface Filling Factor

    International Nuclear Information System (INIS)

    Fenimore, E.E.; Cooper, C.; Ramirez-Ruiz, E.; Sumner, M.C.; Yoshida, A.; Namiki, M.

    1999-01-01

    The variability observed in many complex gamma-ray bursts (GRBs) is inconsistent with causally connected variations in a single, symmetric, relativistic shell interacting with the ambient material (open-quotes external shocksclose quotes). Rather, either the central site must produce ∼10 50 ergs s -1 for hundreds of seconds (open-quotes internal shocksclose quotes), or the local spherical symmetry of the shell must be broken on an angular scale much smaller than Γ -1 , where Γ is the bulk Lorentz factor for the shell. The observed variability in the external shock models arises from the number of causally connected regions that (randomly) become active. We define the surface filling factor to be the ratio of the area of causally connected regions that become active to the observable area of the shell. From the observed variability in 52 BATSE bursts, we estimate the surface filling factor to be typically ∼5x10 -3 , although some values are near unity. We find that the surface filling factor, f, is ∼0.1ΔT/T in both the constant Γ phase (which probably produces the GRB) and the decelerating phase (which probably produces the X-ray afterglows). Here, ΔT is a typical timescale of variability, and T is the time since the initial signal. We analyze the 2 hr flare seen by ASCA 36 hr after the GRB and conclude that the surface filling factor must be small (10 -3 ) in the X-ray afterglow phase as well. Compared with the energy required for an isotropic shell, E iso , explanations for a low surface filling factor can either require more energy (f -1 E iso ∼10 56 ergs) or less energy [(ΔT/4T) 2 E iso ∼10 49 ergs]. Thus, the low filling factor cannot be used as a strong argument that GRBs must be internal shocks. copyright copyright 1999. The American Astronomical Society

  8. Immobile Complex Verbs in Germanic

    DEFF Research Database (Denmark)

    Vikner, Sten

    2005-01-01

    the V° requirements or the V* requirements. Haider (1993, p. 62) and Koopman (1995), who also discuss such immobile verbs, only account for verbs with two prefix-like parts (e.g., German uraufführen ‘to perform (a play) for the first time' or Dutch herinvoeren ‘to reintroduce'), not for the more...... frequent type with only one prefix-like part (e.g., German bauchreden/Dutch buikspreken ‘to ventriloquize'). This analysis will try to account not only for the data discussed in Haider (1993) and Koopman (1995) but also for the following: - why immobile verbs include verbs with only one prefix-like part...... are immobile, - why such verbs are not found in Germanic VO-languages such as English and Scandinavian....

  9. Enhanced activity and stability of L-arabinose isomerase by immobilization on aminopropyl glass.

    Science.gov (United States)

    Zhang, Ye-Wang; Jeya, Marimuthu; Lee, Jung-Kul

    2011-03-01

    Immobilization of Bacillus licheniformis L: -arabinose isomerase (BLAI) on aminopropyl glass modified with glutaraldehyde (4 mg protein g support⁻¹) was found to enhance the enzyme activity. The immobilization yield of BLAI was proportional to the quantity of amino groups on the surface of support. Reducing particle size increased the adsorption capacity (q(m)) and affinity (k(a)). The pH and temperature for immobilization were optimized to be pH 7.1 and 33 °C using response surface methodology (RSM). The immobilized enzyme was characterized and compared to the free enzyme. There is no change in optimal pH and temperature before and after immobilization. However, the immobilized BLAI enzyme achieved 145% of the activity of the free enzyme. Correspondingly, the catalytic efficiency (k(cat)/K(m)) was improved 1.47-fold after immobilization compared to the free enzyme. The thermal stability was improved 138-fold (t₁/₂) increased from 2 to 275 h) at 50 °C following immobilization.

  10. Immobilization of α-amylase onto poly(glycidyl methacrylate) grafted electrospun fibers by ATRP

    International Nuclear Information System (INIS)

    Oktay, Burcu; Demir, Serap; Kayaman-Apohan, Nilhan

    2015-01-01

    In this study, novel α-amylase immobilized poly(vinyl alcohol) (PVA) nanofibers were prepared. The PVA nanofiber surfaces were functionalized with 2-bromoisobutyryl bromide (BiBBr) and followed by surface initiated atom transfer radical polymerization (SI-ATRP) of glycidyl methacrylate (GMA). The morphology of the poly(glycidyl methacrylate) (PGMA) grafted PVA nanofibers was characterized by scanning electron microscopy (SEM). Also PGMA brushes were confirmed by X-ray photo electron microscopy (XPS). α-Amylase was immobilized in a one step process onto the PGMA grafted PVA nanofiber. The characteristic properties of the immobilized and free enzymes were examined. The thermal stability of the enzyme was improved and showed maximum activity at 37 °C by immobilization. pH values of the maximum activity of the free and immobilized enzymes were also found at 6.0 and 6.5, respectively. Free enzyme lost its activity completely within 15 days. The immobilized enzyme lost only 23.8% of its activity within 30 days. - Highlights: • Electrospun photocrosslinkable PVA nanofiber was prepared. • PGMA brushes were conducted on PVA nanofiber via SI-ATRP. • The immobilized enzyme showed maximum activity at pH 6.0 and at 37 °C. • Functionalized nanofibers may be used as promising supports for enzyme immobilization

  11. Applications of factor analysis to electron and ion beam surface techniques

    International Nuclear Information System (INIS)

    Solomon, J.S.

    1987-01-01

    Factor analysis, a mathematical technique for extracting chemical information from matrices of data, is used to enhance Auger electron spectroscopy (AES), core level electron energy loss spectroscopy (EELS), ion scattering spectroscopy (ISS), and secondary ion mass spectroscopy (SIMS) in studies of interfaces, thin films, and surfaces. Several examples of factor analysis enhancement of chemical bonding variations in thin films and at interfaces studied with AES and SIMS are presented. Factor analysis is also shown to be of great benefit in quantifying electron and ion beam doses required to induce surface damage. Finally, examples are presented of the use of factor analysis to reconstruct elemental profiles when peaks of interest overlap each other during the course of depth profile analysis. (author)

  12. Immobilization and controlled release of drug using plasma polymerized thin film

    Energy Technology Data Exchange (ETDEWEB)

    Myung, Sung-Woon [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of); Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, Sunchon 540-742 (Korea, Republic of); Kim, Byung-Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of)

    2015-06-01

    In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release.

  13. Immobilization and controlled release of drug using plasma polymerized thin film

    International Nuclear Information System (INIS)

    Myung, Sung-Woon; Jung, Sang-Chul; Kim, Byung-Hoon

    2015-01-01

    In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release

  14. Immobilization of acid digestion residue

    International Nuclear Information System (INIS)

    Greenhalgh, W.O.; Allen, C.R.

    1983-01-01

    Acid digestion treatment of nuclear waste is similar to incineration processes and results in the bulk of the waste being reduced in volume and weight to some residual solids termed residue. The residue is composed of various dispersible solid materials and typically contains the resultant radioactivity from the waste. This report describes the immobilization of the residue in portland cement, borosilicate glass, and some other waste forms. Diagrams showing the cement and glass virtification parameters are included in the report as well as process steps and candidate waste product forms. Cement immobilization is simplest and probably least expensive; glass vitrification exhibits the best overall volume reduction ratio

  15. Improvement of the homogeneity of protein-imprinted polymer films by orientated immobilization of the template

    International Nuclear Information System (INIS)

    Liu Lijian; Zheng Jingjing; Fang Guijie; Xie Weihong

    2012-01-01

    Highlights: ► MPH was genetically modified at its C-terminal with (Gly-Ser) 5 –Cys. ► MPH-L was immobilized with fixed orientation via disulfide chemistry. ► The immobilized MPH-L retained the activity of MPH. ► MPH-L formed a homogeneous template. ► Homogeneous MIP film was obtained with orientated immobilization of the template. - Abstract: A method for preparing homogeneous protein-imprinted polymer films with orientated immobilization of template is described. The template methyl parathion hydrolase (MPH) was modified with a peptide linker (Gly-Ser) 5 –Cys and was immobilized on a cover glass with a fixed orientation via the linker. The activity of the fusion enzyme (MPH-L) was evaluated by determining the product's absorbance at 405 nm (A 405 ). Both the free and the immobilized MPH-L showed higher retention of the bioactivity than the wide type enzyme (MPH-W) as revealed by the A 405 values for MPH-L free /MPH-W free (1.159/1.111) and for MPH-L immobilized /MPH-W immobilized (0.348/0.118). The immobilized MPH-L also formed a more homogeneous template stamp compared to the immobilized MPH-W. The molecularly imprinted polymer films prepared with the immobilized MPH-L exhibited high homogeneity with low Std. Deviations of 80 and 200 from the CL intensity mean volumes which were observed for batch-prepared films and an individual film, respectively. MPH-L-imprinted polymer film also had a larger template binding capacity indicated by higher CL intensity mean volume of 3900 INT over 2500 INT for MPH-W-imprinted films. The imprinted film prepared with the orientated immobilization of template showed an imprinting factor of 1.7, while the controls did not show an imprinting effect.

  16. Surface Water Quality Assessment and Prioritize the Factors Pollute This Water Using Topsis Fuzzy Hierarchical Analysis

    Directory of Open Access Journals (Sweden)

    Mehdi Komasi

    2017-03-01

    Full Text Available Background & Objective: Nowadays, according to growth of industry and increasing population, water resources are seriousely shortened. This lack of water resources will require special management to be considered in industry and agriculture. Among the various sources of water, surface waters are more susceptible to infection. The most important of these sources of pollution are industrial pollution, detergent, pesticides, radioactive materials, heat and salt concentration.  Materials & methods: In this article, at first the importance of each pollutant will be evaluated base on the effects and its results and then quality evaluation of surface water will be studied. In order to assess the relative importance of these pollutants primarily using TOPSIS software, prioritize these factors as one of the hierarchical analysis and then is modeled with decision tree method using Weka software, the importance of each factor is evaluated and if it does not meet the minimal importance of the decision tree will be removed. Results: The results obtained from the Topsis fuzzy analysis indicate that surface water and groundwater are exposed to pollution about 74% and 26% respectively among the six pollutants examined in this study. In addition, results obtaned from the hierarchical tree in software Weka has shown that the heat factor, soluble salts and industrial pollutants give impac factor or purity about 0.1338, 0.0523 and 1.2694 respectively. Conclusion: Surface water is at greater risk of being polluted compared with groundwater. The heat factor and low concentration of dissolved salts have the low impact and industrial pollutants are considered as the most influential factors in surface water pollution.

  17. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    Science.gov (United States)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-02-02

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. © 2016 Authors.

  18. An experimental method to determine the electrostatic field enhancement factor of a practical conductor surface

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C

    1989-01-01

    A method of determining the field enhancement factor of a practical conductor is presented. The method is developed from a modified theory of discharge onset in a gaseous medium. This modification incorporates the influence of conductor surface roughness. Onset data from an experimental study...

  19. Basement to surface expressions and critical factors in the genesis of unconformity-related deposits

    International Nuclear Information System (INIS)

    Potter, Eric

    2014-01-01

    Two subprojects: 1) Basement to surface expressions of deep mineralization and refinement of critical factors leading to the genesis of unconformity-related uranium deposits; and 2) Recognition of uranium ore system alteration signatures in complex terranes: IOCG vs albite-hosted uranium vs volcanic-hosted uranium.

  20. Evaluation of stress intensity factor for craks in surface of tubes with internal pressure

    International Nuclear Information System (INIS)

    Cesari, F.; Hellen, T.K.

    1977-01-01

    In this report the authors have examined the different methods for calculation of the stress intensity factor in tubes subject at internal pressure with surface cracks. The analysis includes cracks in 2-D axialsymmetric and 3-D. Moreover the authors have clarified the difference between the ASME Sec.11 and the procedure more rigorous

  1. Radiation immobilization of catalase and its application

    International Nuclear Information System (INIS)

    Wang Guanghui; Ha Hongfei; Wang Xia; Wu Jilan

    1988-01-01

    Catalase was immobilized by a chemical method on porous polyacrylamide particles produced by radiation polymerization of acrylamide monomer at low temperature (-78 0 C). Activity of immobilized catalase was enhanced distinctly by joining a chemical arm to the support. The method of recovery of catalase activity on immobilized polymer was found by soaking it in certain buffer. The treatment of H 2 O 2 both in aqueous solution and alcoholic solution by using the immobilized catalase was performed. (author)

  2. Analysis of stress intensity factors for surface cracks in pre/post penetration

    International Nuclear Information System (INIS)

    Miyoshi, Toshiro; Yoshida, Yuichiro

    1988-01-01

    It is important to evaluate the penetration of surface cracks in a Leak-Before-Break analysis. Because the stress intensity factors for surface cracks in pre/post penetration had not yet been analyzed, the authors carried three-dimensional boundary element analyses in order to obtain them. First, the authors developed the technique of nodal breakdown appropriate for cracks with short ligament length in a two-dimensional boundary element analysis. Next, analyses of stress intensity factor for surface cracks in pre/post penetration were carried out using the technique of nodal breakdown for cracks with short ligament length and the three-dimensional boundary element code BEM 3 D which was designed for a supercomputer. (author)

  3. On the Debye-Waller factor in atom-surface scattering

    International Nuclear Information System (INIS)

    Garcia, N.; Maradudin, A.A.; Celli, V.

    1982-01-01

    A theory for the Debye-Waller factor in atom-surface scattering is presented, to lowest order in the phonon contributions. Multiple-scattering effects as well as the cross-correlated surface atom displacements are included. The theory accounts for experimental data without the necessity of introducing the Armand effect, which is due to the finite size of the incident atom. The work presented here implies that the Kirchhoff approximation fails when the energy of the incident particle is in the energy range of the phonon spectrum. The results of the calculation are presented in the high-temperature limit, and it is observed that the Rayleigh surface phonons contribute three-quarters of the Debye-Waller factor, while the bulk phonons account for the rest. This result is interesting because the calculation of the former contribution is simpler than that of the latter. (author)

  4. Laser-assisted immobilization of colloid silver nanoparticles on polyethyleneterephthalate

    Czech Academy of Sciences Publication Activity Database

    Siegel, J.; Lyutakov, O.; Polívková, M.; Staszek, M.; Hubáček, Tomáš; Švorčík, V.

    2017-01-01

    Roč. 420, OCT (2017), s. 661-668 ISSN 0169-4332 R&D Projects: GA MŠk LM2015075 Institutional support: RVO:60077344 Keywords : silver nanoparticles * polyethyleneterephthalate * excimer laser * immobilization Subject RIV: JJ - Other Materials OBOR OECD: Materials engineering Impact factor: 3.387, year: 2016

  5. Immobilization of technetium and nitrate in cement-based materials

    International Nuclear Information System (INIS)

    Tallent, O.K.; McDaniel, E.W.; Del Cul, G.D.; Dodson, K.E.; Trotter, D.R.

    1987-01-01

    The leachabilities of technetium and nitrate wastes immobilized in cement-based grouts have been investigated. Factors found to affect the leachabilities include grout mix ratio, grout fluid density, dry solid blend composition, and waste concentration. 10 refs., 7 figs., 3 tabs

  6. Immobilization and characterization of inulinase from Ulocladium

    Indian Academy of Sciences (India)

    Ulocladium atrum inulinase was immobilized on different composite membranes composed of chitosan/nonwoven fabrics. Km values of free and immobilized U. atrum inulinase on different composite membranes were calculated. The enzyme had optimum pH at 5.6 for free and immobilized U. atrum inulinase on polyester ...

  7. Immobilization of Mitochondria on Graphene

    Science.gov (United States)

    2013-08-29

    poly-L-lysine has also been reported for immobilization of yeast mitochondria. Coating was performed by repetitive washing of cover slips with 0.02...of Poly-L-lysine Applications of PLL PLL is a production of bacterial fermentation and is used as a food preservative. In biology, PLL is used in

  8. Influence of physicochemical factors on microplasticity of surface layer of molybdenum single crystals

    International Nuclear Information System (INIS)

    Savenko, V.I.; Kuchumova, V.M.; Kochanova, L.A.; Shchukin, E.D.

    1984-01-01

    Microplasticity of the surface layer (not more than 10 μm) of a molybdenum monocrystal was investigated by the methods of ultramicrosclerometry and microindentation. Tests of samples with clean surface and with monolayer octadecylamine film were conducted in the air at 60% relative humidity. Microplastic deformation of samples was conducted by slipping of garnet needle on crystal surface with 10 -6 -10 -2 N force. Sclerograms represented etch pits corresponding to dislocation discharges on the surface. The linear density of dislocations in indentor routes and statistic factor (the probability of plastic deformation at assigned force) were used as microplasticity characteristics. It was revealed that plane (111) is the most prone to plastic damage and plane (100) is the least prone to it

  9. Shielding factors for gamma radiation from activity deposited on structures and ground surfaces

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.

    1982-11-01

    This report describes a computer model that calculates shielding factors for indoor residence in multistorey and single-family houses for gamma radiation from activity despoited on roofs, outer walls, and ground surfaces. The dimensions of the buildings including window areas and the nearby surroundings has to be speficied in the calculations. Shielding factors can be calculated for different photon energies and for a uniform surface activity distribution as well as for separate activity on roof, outer wall, and ground surface achieved from decontamination or different deposition velocities. For a given area with a known distribution of different houses a weighted shielding factor can be calculated as well as a time-averaged one based on a given residence time distribution for work/school, home, outdoors, and transportation. Calculated shielding factors are shown for typical Danish houses. To give an impression of the sensitivity of the shielding factor on the parameters used in the model, variations were made in some of the most important parameters: wall thickness, road and ground width, percentage of outer wall covered by windows, photon energy, and decontamination percentage for outer walls, ground and roofs. The uncertainity of the calculations is discussed. (author)

  10. One-pot preparation of conducting composite containing abundant amino groups on electrode surface for electrochemical detection of von willebrand factor

    Science.gov (United States)

    Wang, Wen; Ma, Chao; Li, Yi; Liu, Baihui; Tan, Liang

    2018-03-01

    A one-pot protocol based on cyclic voltammetric scan was employed to prepare new conducting composite that was abundant in amino groups. The scanning electron microscope, atomic force microscope, X-ray photoelectron spectroscopy and infrared spectrum characterization demonstrate that poly(azure A), gold nanoparticles, chitosan and cysteine were immobilized simultaneously on glassy carbon electrode surface. Von Willebrand factor (vWF) antibody (Ab) was subsequently assembled by using glutaraldehyde to construct the Ab/composite-modified electrode. The capture of vWF could inhibit the charge transfer between the ferri-/ferrocyanide probe and the electrode and exert the negative effect on the electrochemical response of the dye polymer in the conducting composite due to the strong steric hindrance effect. The DPV peak current change before and after the immunoreaction was found to be proportional to the logarithm of the vWF concentration from 0.001 to 100 μg mL-1 with a detection limit of 0.4 ng mL-1. The proposed label-free electrochemical method was employed in the investigation on the release of vWF by oxidation-injured vascular endothelial cells. The experimental results exhibit that the vWF content in growth medium was increased when the oxidation injury of the cells was intensified in the presence of H2O2.

  11. Modification of transition's factor in the compact surface-potential-based MOSFET model

    Directory of Open Access Journals (Sweden)

    Kevkić Tijana

    2016-01-01

    Full Text Available The modification of an important transition's factor which enables continual behavior of the surface potential in entire useful range of MOSFET operation is presented. The various modifications have been made in order to obtain an accurate and computationally efficient compact MOSFET model. The best results have been achieved by introducing the generalized logistic function (GL in fitting of considered factor. The smoothness and speed of the transition of the surface potential from the depletion to the strong inversion region can be controlled in this way. The results of the explicit model with this GL functional form for transition's factor have been verified extensively with the numerical data. A great agreement was found for a wide range of substrate doping and oxide thickness. Moreover, the proposed approach can be also applied on the case where quantum mechanical effects play important role in inversion mode.

  12. Improved methane removal in exhaust gas from biogas upgrading process using immobilized methane-oxidizing bacteria.

    Science.gov (United States)

    Sun, Meng-Ting; Yang, Zhi-Man; Fu, Shan-Fei; Fan, Xiao-Lei; Guo, Rong-Bo

    2018-05-01

    Methane in exhaust gas from biogas upgrading process, which is a greenhouse gas, could cause global warming. The biofilter with immobilized methane-oxidizing bacteria (MOB) is a promising approach for methane removal, and the selections of inoculated MOB culture and support material are vital for the biofilter. In this work, five MOB consortia were enriched at different methane concentrations. The MOB-20 consortium enriched at the methane concentration of 20.0% (v/v) was then immobilized on sponge and two particle sizes of volcanic rock in biofilters to remove methane in exhaust gas from biogas upgrading process. Results showed that the immobilized MOB performed more admirable methane removal capacity than suspended cells. The immobilized MOB on sponge reached the highest methane removal efficiency (RE) of 35%. The rough surface, preferable hydroscopicity, appropriate pore size and particle size of support material might favor the MOB immobilization and accordingly methane removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Immobilization of Gibberella fujikuroi cells with carriers modified by radiation polymerization

    International Nuclear Information System (INIS)

    Lu Zhaoxin; Xie Zhongchuan; Wei Qijiang

    1994-01-01

    Gibberella fujikuroi cells were immobilized on modified carriers (gauze) by using the radiation polymerization technique. The mycelium was firmly adhered to the surface of fibril covered with hydrophobic polymer, poly (diethylene glycol dimethyl acrylate) and hydrophobic-hydrophilic copolymer poly (diethylene glycol dimethyl acrylate-sodium acrylate), but it was not immobilized onto the polyethylene net, which has a similar network structure to that of the modified carrier. The weight of immobilized cells was affected by covered polymer. Gibberellic acid productivity in immobilized cells was similar to that of free cells, and the immobilized cells was of good stability. A optimum culture condition for gibberellic acid production was at pH 5.5 and under 20 ∼ 30 degree C

  14. Frozen Microemulsions for MAPLE Immobilization of Lipase

    Directory of Open Access Journals (Sweden)

    Valeria Califano

    2017-12-01

    Full Text Available Candida rugosa lipase (CRL was deposited by matrix assisted pulsed laser evaporation (MAPLE in order to immobilize the enzyme with a preserved native conformation, which ensures its catalytic functionality. For this purpose, the composition of the MAPLE target was optimized by adding the oil phase pentane to a water solution of the amino acid 3-(3,4-dihydroxyphenyl-2-methyl-l-alanine (m-DOPA, giving a target formed by a frozen water-lipase-pentane microemulsion. Fourier transform infrared (FTIR spectroscopy and atomic force microscopy (AFM were used to investigate the structure of MAPLE deposited lipase films. FTIR deconvolution of amide I band indicated a reduction of unfolding and aggregation, i.e., a better preserved lipase secondary structure in the sample deposited from the frozen microemulsion target. AFM images highlighted the absence of big aggregates on the surface of the sample. The functionality of the immobilized enzyme to promote transesterification was determined by thin layer chromatography, resulting in a modified specificity.

  15. Dose behind various immobilization and beam-modifying devices

    International Nuclear Information System (INIS)

    Mellenberg, David E.

    1995-01-01

    Purpose: To quantify the degradation of skin sparing associated with using beam modifiers such as compensators, immobilization devices, and custom blocks for high energy photon beams. Methods and Materials: The degradation of skin sparing was quantified by measuring dose build-up curves with an extrapolation chamber for 6 and 15 MV photon beams. Uniform thickness compensators made of gypsum and lead, thermoplastic mask material, immobilization cradle foam, and cerrobend custom blocks were placed in geometries that mimic relevant clinical situations. Results: Compensators, whether made of gypsum or lead, placed in the linear accelerator's wedge slot did not significantly effect the depth dose curve's build-up region. Immobilization devices such as cradle foam or thermoplastic placed in contact with the patient degrade the skin sparing expected from high energy photon beams proportional to their thickness and density. Measurements behind custom blocks show that surface and near surface doses for a blocked field are best described by build-up curves for an equivalent size open field. Conclusions: These results allow explanation and possibly prediction of skin reactions on patients in which compensators, foam immobilization cradles, thermoplastic masks, or custom blocks are used. These results also provide a baseline by which substitute materials can be evaluated

  16. Synthesis of glycinamides using protease immobilized magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Abha Sahu

    2016-12-01

    Full Text Available In the present investigation, Bacillus subtilis was isolated from slaughterhouse waste and screened for the production of protease enzyme. The purified protease was successfully immobilized on magnetic nanoparticles (MNPs and used for the synthesis of series of glycinamides. The binding and thermal stability of protease on MNPs was confirmed by FTIR spectroscopy and TGA analysis. The surface morphology of MNPs before and after protease immobilization was carried out using SEM analysis. XRD pattern revealed no phase change in MNPs after enzyme immobilization. The processing parameters for glycinamides synthesis viz. temperature, pH, and time were optimized using Response Surface Methodology (RSM by using Design Expert (9.0.6.2. The maximum yield of various amides 2 butyramidoacetic acid (AMD-1,83.4%, 2-benzamidoacetic acid (AMD-2,80.5% and 2,2′((carboxymethyl amino-2-oxoethyl-2-hydroxysuccinylbis(azanediyldiacetic acid (AMD-3,80.8% formed was observed at pH-8, 50 °C and 30 min. The synthesized immobilized protease retained 70% of the initial activity even after 8 cycles of reuse.

  17. Co-immobilization of active antibiotics and cell adhesion peptides on calcium based biomaterials.

    Science.gov (United States)

    Palchesko, Rachelle N; Buckholtz, Gavin A; Romeo, Jared D; Gawalt, Ellen S

    2014-07-01

    Two bioactive molecules with unrelated functions, vancomycin and a cell adhesion peptide, were immobilized on the surface of a potential bone scaffold material, calcium aluminum oxide. In order to accomplish immobilization and retain bioactivity three sequential surface functionalization strategies were compared: 1.) vancomycin was chemically immobilized before a cell adhesion peptide (KRSR), 2.) vancomycin was chemically immobilized after KRSR and 3.) vancomycin was adsorbed after binding the cell adhesion peptide. Both molecules remained on the surface and active using all three reaction sequences and after autoclave sterilization based on osteoblast attachment, bacterial turbidity and bacterial zone inhibition test results. However, the second strategy was superior at enhancing osteoblast attachment and significantly decreasing bacterial growth when compared to the other sequences. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Science.gov (United States)

    Zuluaga-Ramírez, Pablo; Frövel, Malte; Belenguer, Tomás; Salazar, Félix

    2015-01-01

    This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. PMID:28793655

  19. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Directory of Open Access Journals (Sweden)

    Pablo Zuluaga-Ramírez

    2015-11-01

    Full Text Available This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL and realistic variable amplitude loads (VAL, representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications.

  20. Removal factor determination of some local smear papers for surface contamination smear test

    International Nuclear Information System (INIS)

    Suratman; Indriyotomo, D.; Aminjoyo, S.

    1996-01-01

    Removal factor determination of some local smear papers has been done, using dry smear test method. The aim of this research is to find removal values of local smear papers on some surfaces, to replace import smear papers. Smear test was done on the various surfaces i.e.: porcelain, formica, glass, stainless steel, steel and PVC, with the local smear papers I.e.: Padalarang, Diagonal, Concorde, Marga, Hard Cloth, and import smear paper. The artificial contaminant which used were I-131 and P-32. The removal factor values of Padalarang paper for surfaces: porcelain, formica, glass stainless steel, steel and PVC were: 24.5%, 20.0%, 27.0%, 6.8%, 4.9%, and 13.6% respectively. The removal factor values of Diagonal paper were:18.4%, 15.9%, 5.7%, 3.5%, and 9.1% respectively. The removal factor values of concord paper were: 18.5%, 20.3%, 23.1%, 6.6%, 3.8%, and 9.0% respectively. The removal factor values of Marga paper were: 16.7%, 13.5%, 21.1%, 4.2%, 4.1% and 8.1% respectively. The removal factor values of Hard Cloth were: 18.6%, 12.6%, 20.5%, 8.2%, and 10.1% respectively. The removal factor values of import smear paper were: 17.8%, 15.0%, 18.8%, 9.1%, 4.8%, and 14.4% respectively . Substitution alternative of import smear paper is Padalarang. (author)

  1. The mechanisms of heavy metal immobilization by cementitious material treatments and thermal treatments: A review.

    Science.gov (United States)

    Guo, Bin; Liu, Bo; Yang, Jian; Zhang, Shengen

    2017-05-15

    Safe disposal of solid wastes containing heavy metals is a significant task for environment protection. Immobilization treatment is an effective technology to achieve this task. Cementitious material treatments and thermal treatments are two types of attractive immobilization treatments due to that the heavy metals could be encapsulated in their dense and durable wasteforms. This paper discusses the heavy metal immobilization mechanisms of these methods in detail. Physical encapsulation and chemical stabilization are two fundamental mechanisms that occur simultaneously during the immobilization processes. After immobilization treatments, the wasteforms build up a low permeable barrier for the contaminations. This reduces the exposed surface of wastes. Chemical stabilization occurs when the heavy metals transform into more stable and less soluble metal bearing phases. The heavy metal bearing phases in the wasteforms are also reviewed in this paper. If the heavy metals are incorporated into more stable and less soluble metal bearing phases, the potential hazards of heavy metals will be lower. Thus, converting heavy metals into more stable phases during immobilization processes should be a common way to enhance the immobilization effect of these immobilization methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Ethanol production from concentrated food waste hydrolysates with yeast cells immobilized on corn stalk

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shoubao [Huainan Normal Univ., Anhui (China). School of Life Science; Chen, Xiangsong; Wu, Jingyong; Wang, Pingchao [Chinese Academy of Sciences, Hefei (China). Key Lab. of Ion Beam Bio-engineering of Inst. of Plasma Physics

    2012-05-15

    The aim of the present study was to examine ethanol production from concentrated food waste hydrolysates using whole cells of S. cerevisiae immobilized on corn stalks. In order to improve cell immobilization efficiency, biological modification of the carrier was carried out by cellulase hydrolysis. The results show that proper modification of the carrier with cellulase hydrolysis was suitable for cell immobilization. The mechanism proposed, cellulase hydrolysis, not only increased the immobilized cell concentration, but also disrupted the sleek surface to become rough and porous, which enhanced ethanol production. In batch fermentation with an initial reducing sugar concentration of 202.64 {+-} 1.86 g/l, an optimal ethanol concentration of 87.91 {+-} 1.98 g/l was obtained using a modified corn stalk-immobilized cell system. The ethanol concentration produced by the immobilized cells was 6.9% higher than that produced by the free cells. Ethanol production in the 14th cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in an immobilized cell reactor, the maximum ethanol concentration of 84.85 g/l, and the highest ethanol yield of 0.43 g/g (of reducing sugar) were achieved at hydraulic retention time (HRT) of 3.10 h, whereas the maximum volumetric ethanol productivity of 43.54 g/l/h was observed at a HRT of 1.55 h. (orig.)

  3. Cadmium immobilization by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Smičiklas Ivana D.

    2003-01-01

    Full Text Available The contamination of air, soil and water by cadmium is a great environmental problem. If cadmium occurs in nature in ionic form, soluble in water, it easily enters into the food chain. Hydroxyapatite (HAP, Ca-o(POAe(OH2 is a sparingly soluble salt and an excellent matrix for the removal of heavy metals from solutions. Considerable research attention has been paid to the bond between Cc/2+ ions and synthetic hydroxyapatite of known composition. The sorption mechanism is complex. The dominant process is ion exchange, but surface adsorption, surface complexation and coprecipitation can also contribute to the overall mechanism. The sorption capacity depends on the characteristics of hydroxyapatite itself and on the experimental conditions. Under optimum conditions a maximum capacity of 0.8 mol Cd2+/mol HAP can be achieved. HAP is a potential sorbent for the remediation of contaminated water and soil, for industrial waste treatment, and it is also referenced as a material that can be used as a barrier around waste depositories.

  4. Biodiesel production with immobilized lipase: A review.

    Science.gov (United States)

    Tan, Tianwei; Lu, Jike; Nie, Kaili; Deng, Li; Wang, Fang

    2010-01-01

    Fatty acid alkyl esters, also called biodiesel, are environmentally friendly and show great potential as an alternative liquid fuel. Biodiesel is produced by transesterification of oils or fats with chemical catalysts or lipase. Immobilized lipase as the biocatalyst draws high attention because that process is "greener". This article reviews the current status of biodiesel production with immobilized lipase, including various lipases, immobilization methods, various feedstocks, lipase inactivation caused by short chain alcohols and large scale industrialization. Adsorption is still the most widely employed method for lipase immobilization. There are two kinds of lipase used most frequently especially for large scale industrialization. One is Candida antartica lipase immobilized on acrylic resin, and the other is Candida sp. 99-125 lipase immobilized on inexpensive textile membranes. However, to further reduce the cost of biodiesel production, new immobilization techniques with higher activity and stability still need to be explored. Copyright 2010 Elsevier Inc. All rights reserved.

  5. Removal of nitrate using Paracoccus sp. YF1 immobilized on bamboo carbon

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan; Gan, Li [School of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, Fujian Province (China); Chen, Zuliang, E-mail: Zuliang.chen@unisa.edu.au [School of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, Fujian Province (China); Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, Mawson Lakes, SA 5095 (Australia); Megharaj, Mallavarapu; Naidu, Ravi [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, Mawson Lakes, SA 5095 (Australia)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Paracoccus sp. immobilized on bamboo carbon used for the denitrification. Black-Right-Pointing-Pointer The rate of denitrification increased using the immobilized cells. Black-Right-Pointing-Pointer 99.8% denitrification was maintained after 10-cycle reuse. Black-Right-Pointing-Pointer Demonstrating an excellent reusability and a potential technique. - Abstract: Paracoccus sp. strain YF1 immobilized on bamboo carbon was developed for the denitrification. The results show that denitrification was significantly improved using immobilized cells compared to that of free cells, where denitrification time decreased from 24 h (free cells) to 15 h (immobilized cells). The efficiency of denitrification increased from 4.57 mg/(L h) (free cells) to 6.82 mg/(L h) (immobilized cells). Kinetics studies suggest that denitrification by immobilized YF1 cells fitted well to the zero-order model. Scanning electron microscopy (SEM) demonstrated that firstly, the bacteria became stable on the inside and exterior of the bamboo carbon particles and secondly, they formed biofilm after adhesion. Various factors and their influences on biological denitrification were investigated, namely temperature, pH, initial nitrate concentrations and carbon sources. The immobilized cells exhibited more nitrate removal at various conditions compared to free cells since bamboo carbon as a carrier protects cells against changes in environmental conditions. Denitrification using the YF1 immobilized in bamboo carbon was also maintained 99.8% after the tenth cycle reuse, thus demonstrating excellent reusability. Finally, wastewater was treated using the immobilized cells and the outcome was that nitrogen was completely removed by bamboo-immobilized YF1.

  6. Removal of nitrate using Paracoccus sp. YF1 immobilized on bamboo carbon

    International Nuclear Information System (INIS)

    Liu, Yan; Gan, Li; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

    2012-01-01

    Highlights: ► Paracoccus sp. immobilized on bamboo carbon used for the denitrification. ►The rate of denitrification increased using the immobilized cells. ► 99.8% denitrification was maintained after 10-cycle reuse. ► Demonstrating an excellent reusability and a potential technique. - Abstract: Paracoccus sp. strain YF1 immobilized on bamboo carbon was developed for the denitrification. The results show that denitrification was significantly improved using immobilized cells compared to that of free cells, where denitrification time decreased from 24 h (free cells) to 15 h (immobilized cells). The efficiency of denitrification increased from 4.57 mg/(L h) (free cells) to 6.82 mg/(L h) (immobilized cells). Kinetics studies suggest that denitrification by immobilized YF1 cells fitted well to the zero-order model. Scanning electron microscopy (SEM) demonstrated that firstly, the bacteria became stable on the inside and exterior of the bamboo carbon particles and secondly, they formed biofilm after adhesion. Various factors and their influences on biological denitrification were investigated, namely temperature, pH, initial nitrate concentrations and carbon sources. The immobilized cells exhibited more nitrate removal at various conditions compared to free cells since bamboo carbon as a carrier protects cells against changes in environmental conditions. Denitrification using the YF1 immobilized in bamboo carbon was also maintained 99.8% after the tenth cycle reuse, thus demonstrating excellent reusability. Finally, wastewater was treated using the immobilized cells and the outcome was that nitrogen was completely removed by bamboo-immobilized YF1.

  7. A facile and efficient method of enzyme immobilization on silica particles via Michael acceptor film coatings: immobilized catalase in a plug flow reactor.

    Science.gov (United States)

    Bayramoglu, Gulay; Arica, M Yakup; Genc, Aysenur; Ozalp, V Cengiz; Ince, Ahmet; Bicak, Niyazi

    2016-06-01

    A novel method was developed for facile immobilization of enzymes on silica surfaces. Herein, we describe a single-step strategy for generating of reactive double bonds capable of Michael addition on the surfaces of silica particles. This method was based on reactive thin film generation on the surfaces by heating of impregnated self-curable polymer, alpha-morpholine substituted poly(vinyl methyl ketone) p(VMK). The generated double bonds were demonstrated to be an efficient way for rapid incorporation of enzymes via Michael addition. Catalase was used as model enzyme in order to test the effect of immobilization methodology by the reactive film surface through Michael addition reaction. Finally, a plug flow type immobilized enzyme reactor was employed to estimate decomposition rate of hydrogen peroxide. The highly stable enzyme reactor could operate continuously for 120 h at 30 °C with only a loss of about 36 % of its initial activity.

  8. Influence of chirality on catalytic generation of nitric oxide and platelet behavior on selenocystine immobilized TiO2 films.

    Science.gov (United States)

    Fan, Yonghong; Pan, Xiaxin; Wang, Ke; Wu, Sisi; Han, Honghong; Yang, Ping; Luo, Rifang; Wang, Hong; Huang, Nan; Tan, Wei; Weng, Yajun

    2016-09-01

    As nitric oxide (NO) plays vital roles in the cardiovascular system, incorporating this molecule into cardiovascular stents is considered as an effective method. In the present study, selenocystine with different chirality (i.e., l- and d-selenocystine) was used as the catalytic molecule immobilized on TiO2 films for decomposing endogenous NO donor. The influences of surface chirality on NO release and platelet behavior were evaluated. Results show that although the amount of immobilized l-selenocystine on the surface was nearly the same as that of immobilized d-selenocystine, in vitro catalytic NO release tests showed that l-selenocystine immobilized surfaces were more capable of catalyzing the decomposition of S-nitrosoglutathione and thus generating more NO. Accordingly, l-selenocystine immobilized surfaces demonstrated significantly increased inhibiting effects on the platelet adhesion and activation, when compared to d-selenocystine immobilized ones. Measurement of the cGMP concentration of platelets further confirmed that surface chirality played an important role in regulating NO generation and platelet behaviors. Additionally, using bovine serum albumin and fibrinogen as model proteins, the protein adsorption determined with quartz crystal microbalance showed that the l-selenocystine immobilized surface enhanced protein adsorption. In conclusion, surface chirality significantly influences protein adsorption and NO release, which may have significant implications in the design of NO-generating cardiovascular stents. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Determination of conversion factors and efficiency for GM detectors used in measurements of surface pollution

    International Nuclear Information System (INIS)

    Ayala G, J.; Alvarez R, J.T.

    1999-01-01

    One of the objectives of the Radiation protection, is to observe with the National and as International standardization referring to the ICRP dose limitation system (ICRP 26, ICRP 60). In this work it was treated the problem corresponding about how to determine the conversion factor of cpm/mR/h and the absolute efficiency ε, for a Geiger-Muller equipment with thin window. This equipment is used for the beta particle detection. Thus the correct use of calibration factors and the procedures to convert cpm in Bq is expedited and also to apply the ISO procedure for to evaluate contaminated surfaces. (Author)

  10. A sensitive electrochemiluminescence cytosensor for quantitative evaluation of epidermal growth factor receptor expressed on cell surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yanjuan; Zhang, Shaolian; Wen, Qingqing; Huang, Hongxing; Yang, Peihui, E-mail: typh@jnu.edu.cn

    2015-06-30

    Highlights: • EGF-cytosensor was used for evaluating EGFR expression level on cell surfaces. • CdSQDs and EGF were coated on magnetic beads (MBs) for ECL-probe. • Good sensitivity was achieved due to the signal amplification of ECL-probe. - Abstract: A sensitive electrochemiluminescence (ECL) strategy for evaluating the epidermal growth factor receptor (EGFR) expression level on cell surfaces was designed by integrating the specific recognition of EGFR expressed on MCF-7 cell surfaces with an epidermal growth factor (EGF)-funtionalized CdS quantum dots (CdSQDs)-capped magnetic bead (MB) probe. The high sensitivity of ECL probe of EGF-funtionalized CdSQD-capped-MB was used for competitive recognition with EGFR expressed on cell surfaces with recombinant EGFR protein. The changes of ECL intensity depended on both the cell number and the expression level of EGFR receptor on cell surfaces. A wide linear response to cells ranging from 80 to 4 × 10{sup 6} cells mL{sup −1} with a detection limit of 40 cells mL{sup −1} was obtained. The EGF-cytosensor was used to evaluate EGFR expression levels on MCF-7 cells, and the average number of EGFR receptor on single MCF-7 cells was 1.35 × 10{sup 5} with the relative standard deviation of 4.3%. This strategy was further used for in-situ and real-time evaluating EGFR receptor expressed on cell surfaces in response to drugs stimulation at different concentration and incubation time. The proposed method provided potential applications in the detection of receptors on cancer cells and anticancer drugs screening.

  11. Tailoring Surface Impurity Content to Maximize Q-factors of Superconducting Resonators

    Energy Technology Data Exchange (ETDEWEB)

    Martinello, Martina [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Checchin, Mattia [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Grassellino, Anna [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Melnychuk, Oleksandr [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Posen, Sam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Romanenko, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Sergatskov, Dmitri [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Zasadzinski, John [Illinois Inst. of Technology, Chicago, IL (United States)

    2016-06-01

    Quality factor of superconducting radio-frequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of flux trapped, depends on the mean free path. A variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different N-doping) were studied in order to cover the largest range of mean free path nowadays achievable, from few to thousands of nanometers. A bell shaped trend appears for the range of mean free path studied. Over doped cavities falls at the maximum of this curve defining the largest values of sensitivity. In addition, we have also studied the trend of the BCS surface resistance contribution as a function of mean free path, revealing that N-doped cavities follow close to the theoretical minimum of the BCS surface resistance as a function of the mean free path. Adding these results together we unveil that optimal N-doping treatment allows to maximize Q-factor at 2 K and 16 MV/m until the magnetic field fully trapped during the cavity cooldown stays below 10 mG.

  12. Immobilization of iodine in concrete

    Science.gov (United States)

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  13. The development, characterization, and application of biomimetic nanoscale enzyme immobilization

    Science.gov (United States)

    Haase, Nicholas R.

    The utilization of enzymes is of interest for applications such as biosensors and biofuel cells. Immobilizing enzymes provides a means to develop these applications. Previous immobilization efforts have been accomplished by exposing surfaces on which silica-forming molecules are present to solutions containing an enzyme and a silica precursor. This approach leads to the enzyme being entrapped in a matrix three orders of magnitude larger than the enzyme itself, resulting in low retention of enzyme activity. The research herein introduces a method for the immobilization of enzymes during the layer-by-layer buildup of Si-O and Ti-O coatings which are nanoscale in thickness. This approach is an application of a peptide-induced mineral deposition method developed in the Sandhage and Kroger groups, and it involves the alternating exposure of a surface to solutions containing the peptide protamine and then an aqueous precursor solution of silicon- or titanium-oxide at near-neutral pH. A method has been developed that enables in situ immobilization of enzymes in the protamine/mineral oxide coatings. Depending on the layer and mineral (silica or titania) within which the enzyme is incorporated, the resulting multilayer biocatalytic hybrid materials retain 20 -- 100% of the enzyme activity. Analyses of kinetic properties of the immobilized enzyme, coupled with characterization of physical properties of the mineral-bearing layers (thickness, porosity, pore size distribution), indicates that the catalytic activities of the enzymes immobilized in the different layers are largely determined by substrate diffusion. The enzyme was also found to be substantially stabilized against heat-induced denaturation and largely protected from proteolytic attack. These functional coatings are then developed for use as antimicrobial materials. Glucose oxidase, which catalyzes production of the cytotoxic agent hydrogen peroxide, was immobilized with silver nanoparticles, can release

  14. Immobilization of olfactory receptors onto gold electrodes for electrical biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Casuso, Ignacio [Departament d' Electronica, Universitat de Barcelona, Laboratori de Nanobioenginyeria-IBEC, Parc Cientific de Barcelona, C/Josep Samitier 1-5, Barcelona (Spain)], E-mail: icasuso@pcb.ub.es; Pla-Roca, Mateu [Departament d' Electronica, Universitat de Barcelona, Laboratori de Nanobioenginyeria-IBEC, Parc Cientific de Barcelona, C/Josep Samitier 1-5, Barcelona (Spain); Gomila, Gabriel [Departament d' Electronica, Universitat de Barcelona, Laboratori de Nanobioenginyeria-IBEC, Parc Cientific de Barcelona, C/Josep Samitier 1-5, Barcelona (Spain)], E-mail: ggomila@pcb.ub.es; Samitier, Josep [Departament d' Electronica, Universitat de Barcelona, Laboratori de Nanobioenginyeria-IBEC, Parc Cientific de Barcelona, C/Josep Samitier 1-5, Barcelona (Spain); Minic, Jasmina; Persuy, Marie A.; Salesse, Roland; Pajot-Augy, Edith [INRA, Neurobiologie de l' Olfaction et de la Prise Alimentaire, Equipe Recepteurs et Communication Chimique, Domaine de Vilvert, Jouy en Josas Cedex (France)

    2008-07-01

    We investigate the immobilization of native nanovesicles containing functional olfactory receptors onto gold electrodes by means of atomic force microscopy in liquid. We show that nanovesicles can be adsorbed without disrupting them presenting sizes once immobilized ranging from 50 nm to 200 nm in diameter. The size of the nanovesicles shows no dependence on the electrode hydrophobicity being constant in a height/width ratio close to 1:3. Nevertheless, electrode hydrophobicity does affect the surface coverage, the surface coverage is five times higher in hydrophilic electrodes than on hydrophobic ones. Surface coverage is also affected by nanovesicles dimensions in suspension, the size homogenization to around 50 nm yields a further five fold increment in surface coverage achieving a coverage of about 50% close to the hard spheres jamming limit (54.7%). A single layer of nanovesicles is always formed with no particle overlap. Present results provide insights into the immobilization on electrodes of olfactory receptors for further olfactory electrical biosensor development.

  15. Immobilization of chlorine dioxide modified cells for uranium absorption

    International Nuclear Information System (INIS)

    He, Shengbin; Ruan, Binbiao; Zheng, Yueping; Zhou, Xiaobin; Xu, Xiaoping

    2014-01-01

    There has been a trend towards the use of microorganisms to recover metals from industrial wastewater, for which various methods have been reported to be used to improve microorganism adsorption characteristics such as absorption capacity, tolerance and reusability. In present study, chlorine dioxide(ClO 2 ), a high-efficiency, low toxicity and environment-benign disinfectant, was first reported to be used for microorganism surface modification. The chlorine dioxide modified cells demonstrated a 10.1% higher uranium adsorption capacity than control ones. FTIR analysis indicated that several cell surface groups are involved in the uranium adsorption and cell surface modification. The modified cells were further immobilized on a carboxymethylcellulose (CMC) matrix to improve their reusability. The cell-immobilized adsorbent could be employed either in a high concentration system to move vast UO 2 2+ ions or in a low concentration system to purify UO 2 2+ contaminated water thoroughly, and could be repeatedly used in multiple adsorption-desorption cycles with about 90% adsorption capacity maintained after seven cycles. - Highlights: • Chlorine dioxide was first reported to be used for microorganism surface modification. • The chlorine dioxide modified cells demonstrated a 10.1% higher uranium adsorption capacity than control ones. • The chlorine dioxide modified cells were further immobilized by carboxymethylcellulose to improve their reusability

  16. Analysis of the Pathogenic Factors and Management of Dry Eye in Ocular Surface Disorders.

    Science.gov (United States)

    Nebbioso, Marcella; Del Regno, Paola; Gharbiya, Magda; Sacchetti, Marta; Plateroti, Rocco; Lambiase, Alessandro

    2017-08-13

    The tear film represents the interface between the eye and the environment. The alteration of the delicate balance that regulates the secretion and distribution of the tear film determines the dry eye (DE) syndrome. Despite having a multifactorial origin, the main risk factors are female gender and advanced age. Likewise, morphological changes in several glands and in the chemical composition of their secretions, such as proteins, mucins, lipidics, aqueous tears, and salinity, are highly relevant factors that maintain a steady ocular surface. Another key factor of recurrence and onset of the disease is the presence of local and/or systemic inflammation that involves the ocular surface. DE syndrome is one of the most commonly encountered diseases in clinical practice, and many other causes related to daily life and the increase in average life expectancy will contribute to its onset. This review will consider the disorders of the ocular surface that give rise to such a widespread pathology. At the end, the most recent therapeutic options for the management of DE will be briefly discussed according to the specific underlying pathology.

  17. Stabilization of dimeric β-glucosidase from Aspergillus niger via glutaraldehyde immobilization under different conditions.

    Science.gov (United States)

    Vazquez-Ortega, Perla Guadalupe; Alcaraz-Fructuoso, Maria Teresa; Rojas-Contreras, Juan A; López-Miranda, Javier; Fernandez-Lafuente, Roberto

    2018-03-01

    The dimeric enzyme β-glucosidase from Aspergillus niger has been immobilized on different amino-agarose beads at pH 5 and 7, exploiting the versatility of glutaraldehyde. The stability of the free enzyme depended on enzyme concentration. Immobilization via ion exchange improved enzyme stability/activity, depending on the immobilization pH. However, the enzyme was desorbed in 75 mM NaCl at pH 7 and some stability/enzyme concentration dependence still existed. of these biocatalysts with glutaraldehyde increased enzyme stability (e.g. at pH 5, after incubation under conditions where the enzyme just ionically exchanged was fully inactivated, the activity of the glutaraldehyde treated enzyme remained unaltered). Immobilization on glutaraldehyde pre-activated supports yielded a higher increase in enzyme activity, but the stabilization was lower. While when measuring the enzyme activity at pH 4 there were no changes after immobilization, all immobilized enzymes were more active than the free enzyme at pH 6 and 7 (2-3 times). The Ki/Km ratio did not significantly decrease in any immobilized biocatalysts, and in some cases it worsened in a significant way (by a 9 fold factor using preactivated supports). The new biocatalysts are significantly more stable and avoid enzyme subunit desorption, being the immobilization pH a key point in their design. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Nanostructured ZnO-based biosensor: DNA immobilization and hybridization

    Directory of Open Access Journals (Sweden)

    Ahmed Mishaal Mohammed

    2017-09-01

    Full Text Available An electrochemical DNA biosensor was successfully fabricated by using (3-aminopropyl triethoxysilane (APTES with zinc oxide (ZnO nanorods synthesized using microwave-assisted chemical bath deposition method on thermally oxidized SiO2 thin films. The structural quality and morphology of the ZnO nanorods were determined by employing scanning electron microscopy (SEM and X-ray diffraction (XRD, which show a hexagonal wurtzite structure with a preferred orientation along the (101 direction. The surface of the SiO2 thin films was chemically modified with ZnO. Label-free detection DNA immobilization and hybridization were performed using potassium hexacyanoferrate with cyclic voltammetry (CV measurements. The capacitance, permittivity, and conductivity profiles of the fabricated sensor clearly indicate DNA immobilization and hybridization. Results show that the capacitance values of bare, ZnO- modified surface immobilization, and target DNA hybridization were 46×10−12F, 47×10−8F, 27μF, and 17μF, respectively, at 1Hz. The permittivity measurement increased from 3.94×103 to 251×103 and 165×103 at the frequency range of approximately 200 to 1Hz for bare and DNA immobilization and hybridization, respectively. The measured conductivity values for the bare, ZnO, immobilized, and hybridization device were 2.4×10−9, 10×10−8, 1.6×10−7, and 1.3×10−7Scm−1, respectively. Keywords: Zinc oxide, Biosensor, Capacitance, Permittivity, Conductivity

  19. Contaminant immobilization via microbial activity

    International Nuclear Information System (INIS)

    1991-11-01

    The aim of this study was to search the literature to identify biological techniques that could be applied to the restoration of contaminated groundwaters near uranium milling sites. Through bioremediation it was hypothesized that the hazardous heavy metals could be immobilized in a stable, low-solubility form, thereby halting their progress in the migrating groundwater. Three basic mechanisms were examined: reduction of heavy metals by microbially produced hydrogen sulfide; direct microbial mediated reduction; and biosorption

  20. Immobilization of iodine in concrete

    International Nuclear Information System (INIS)

    Clark, W.E.; Thompson, C.T.

    1977-01-01

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3 to 20 wt percent iodine as Ba(IO 3 ) 2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO 3 ) 2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. 10 claims, 2 figures

  1. Effect of extracytoplasmic function sigma factors on autoaggregation, hemagglutination, and cell surface properties of Porphyromonas gingivalis

    Science.gov (United States)

    Kokubu, Eitoyo; Okamoto-Shibayama, Kazuko; Ishihara, Kazuyuki

    2017-01-01

    Porphyromonas gingivalis is a bacterium frequently isolated from chronic periodontal lesions and is involved in the development of chronic periodontitis. To colonize the gingival crevice, P. gingivalis has to adapt to environmental stresses. Microbial gene expression is regulated by transcription factors such as those in two-component systems and extracytoplasmic function (ECF) sigma factors. ECF sigma factors are involved in the regulation of environmental stress response genes; however, the roles of individual ECF sigma factors are largely unknown. The purpose of this study was to investigate the functions, including autoaggregation, hemagglutination, gingipain activity, susceptibility to antimicrobial agents, and surface structure formation, of P. gingivalis ECF sigma factors encoded by SigP (PGN_0274), SigCH (PGN_0319), PGN_0450, PGN_0970, and SigH (PGN_1740). Various physiological aspects of the sigP mutant were affected; autoaggregation was significantly decreased at 60 min (p < 0.001), hemagglutination activity was markedly reduced, and enzymatic activities of Kgp and Rgps were significantly decreased (p < 0.001). The other mutants also showed approximately 50% reduction in Rgps activity. Kgp activity was significantly reduced in the sigH mutant (p < 0.001). No significant differences in susceptibilities to tetracycline and ofloxacin were observed in the mutants compared to those of the wild-type strain. However, the sigP mutant displayed an increased susceptibility to ampicillin, whereas the PGN_0450 and sigH mutants showed reduced susceptibility. Transmission electron microscopy images revealed increased levels of outer membrane vesicles formed at the cell surfaces of the sigP mutant. These results indicate that SigP is important for bacterial surface-associated activities, including gingipain activity, autoaggregation, hemagglutination, vesicle formation, and antimicrobial susceptibility. PMID:28931045

  2. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry.

    Science.gov (United States)

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan

    2016-03-16

    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%.

  3. The 1.7 Å X-ray crystal structure of the porcine factor VIII C2 domain and binding analysis to anti-human C2 domain antibodies and phospholipid surfaces.

    Directory of Open Access Journals (Sweden)

    Caileen M Brison

    Full Text Available The factor VIII C2 domain is essential for binding to activated platelet surfaces as well as the cofactor activity of factor VIII in blood coagulation. Inhibitory antibodies against the C2 domain commonly develop following factor VIII replacement therapy for hemophilia A patients, or they may spontaneously arise in cases of acquired hemophilia. Porcine factor VIII is an effective therapeutic for hemophilia patients with inhibitor due to its low cross-reactivity; however, the molecular basis for this behavior is poorly understood. In this study, the X-ray crystal structure of the porcine factor VIII C2 domain was determined, and superposition of the human and porcine C2 domains demonstrates that most surface-exposed differences cluster on the face harboring the "non-classical" antibody epitopes. Furthermore, antibody-binding results illustrate that the "classical" 3E6 antibody can bind both the human and porcine C2 domains, although the inhibitory titer to human factor VIII is 41 Bethesda Units (BU/mg IgG versus 0.8 BU/mg IgG to porcine factor VIII, while the non-classical G99 antibody does not bind to the porcine C2 domain nor inhibit porcine factor VIII activity. Further structural analysis of differences between the electrostatic surface potentials suggest that the C2 domain binds to the negatively charged phospholipid surfaces of activated platelets primarily through the 3E6 epitope region. In contrast, the G99 face, which contains residue 2227, should be distal to the membrane surface. Phospholipid binding assays indicate that both porcine and human factor VIII C2 domains bind with comparable affinities, and the human K2227A and K2227E mutants bind to phospholipid surfaces with similar affinities as well. Lastly, the G99 IgG bound to PS-immobilized factor VIII C2 domain with an apparent dissociation constant of 15.5 nM, whereas 3E6 antibody binding to PS-bound C2 domain was not observed.

  4. Poly(acrylonitrile)chitosan composite membranes for urease immobilization.

    Science.gov (United States)

    Gabrovska, Katya; Georgieva, Aneliya; Godjevargova, Tzonka; Stoilova, Olya; Manolova, Nevena

    2007-05-10

    (Poly)acrylonitrile/chitosan (PANCHI) composite membranes were prepared. The chitosan layer was deposited on the surface as well as on the pore walls of the base membrane. This resulted in the reduction of the pore size of the membrane and in an increase of their hydrophilicity. The pore structure of PAN and PANCHI membranes were determined by TEM and SEM analyses. It was found that the average size of the pore under a selective layer base PAN membrane is 7 microm, while the membrane coated with 0.25% chitosan shows a reduced pore size--small or equal to 5 microm and with 0.35% chitosan--about 4 microm. The amounts of the functional groups, the degree of hydrophilicity and transport characteristics of PAN/Chitosan composite membranes were determined. Urease was covalently immobilized onto all kinds of PAN/chitosan composite membranes using glutaraldehyde. Both the amount of bound protein and relative activity of immobilized urease were measured. The highest activity (94%) was measured for urease bound to PANCHI2 membranes (0.25% chitosan). The basic characteristics (pH(opt), pH(stability), T(opt), T(stability), heat inactivation and storage stability) of immobilized urease were determined. The obtained results show that the poly(acrylonitrile)chitosan composite membranes are suitable for enzyme immobilization.

  5. Porphyromonas gingivalis Uses Specific Domain Rearrangements and Allelic Exchange to Generate Diversity in Surface Virulence Factors.

    Science.gov (United States)

    Dashper, Stuart G; Mitchell, Helen L; Seers, Christine A; Gladman, Simon L; Seemann, Torsten; Bulach, Dieter M; Chandry, P Scott; Cross, Keith J; Cleal, Steven M; Reynolds, Eric C

    2017-01-01

    Porphyromonas gingivalis is a keystone pathogen of chronic periodontitis. The virulence of P. gingivalis is reported to be strain related and there are currently a number of strain typing schemes based on variation in capsular polysaccharide, the major and minor fimbriae and adhesin domains of Lys-gingipain (Kgp), amongst other surface proteins. P. gingivalis can exchange chromosomal DNA between strains by natural competence and conjugation. The aim of this study was to determine the genetic variability of P. gingivalis strains sourced from international locations over a 25-year period and to determine if variability in surface virulence factors has a phylogenetic basis. Whole genome sequencing was performed on 13 strains and comparison made to 10 previously sequenced strains. A single nucleotide polymorphism-based phylogenetic analysis demonstrated a shallow tri-lobed phylogeny. There was a high level of reticulation in the phylogenetic network, demonstrating extensive horizontal gene transfer between the strains. Two highly conserved variants of the catalytic domain of the major virulence factor the Kgp proteinase (Kgp cat I and Kgp cat II) were found. There were three variants of the fourth Kgp C-terminal cleaved adhesin domain. Specific variants of the cell surface proteins FimA, FimCDE, MfaI, RagAB, Tpr, and PrtT were also identified. The occurrence of all these variants in the P. gingivalis strains formed a mosaic that was not related to the SNP-based phylogeny. In conclusion P. gingivalis uses domain rearrangements and genetic exchange to generate diversity in specific surface virulence factors.

  6. Controls of evapotranspiration and CO2 fluxes from scots pine by surface conductance and abiotic factors.

    Directory of Open Access Journals (Sweden)

    Tianshan Zha

    Full Text Available Evapotranspiration (E and CO2 flux (Fc in the growing season of an unusual dry year were measured continuously over a Scots pine forest in eastern Finland, by eddy covariance techniques. The aims were to gain an understanding of their biological and environmental control processes. As a result, there were obvious diurnal and seasonal changes in E, Fc , surface conductance (gc , and decoupling coefficient (Ω, showing similar trends to those in radiation (PAR and vapour pressure deficit (δ. The maximum mean daily values (24-h average for E, Fc , gc , and Ω were 1.78 mmol m(-2 s(-1, -11.18 µmol m(-2 s(-1, 6.27 mm s(-1, and 0.31, respectively, with seasonal averages of 0.71 mmol m(-2 s(-1, -4.61 µmol m(-2 s(-1, 3.3 mm s(-1, and 0.16. E and Fc were controlled by combined biological and environmental variables. There was curvilinear dependence of E on gc and Fc on gc . Among the environmental variables, PAR was the most important factor having a positive linear relationship to E and curvilinear relationship to Fc , while vapour pressure deficit was the most important environmental factor affecting gc . Water use efficiency was slightly higher in the dry season, with mean monthly values ranging from 6.67 to 7.48 μmol CO2 (mmol H2O(-1 and a seasonal average of 7.06 μmol CO2 (μmol H2O(-1. Low Ω and its close positive relationship with gc indicate that evapotranspiration was sensitive to surface conductance. Mid summer drought reduced surface conductance and decoupling coefficient, suggesting a more biotic control of evapotranspiration and a physiological acclimation to dry air. Surface conductance remained low and constant under dry condition, supporting that a constant value of surface constant can be used for modelling transpiration under drought condition.

  7. Immobilization of Glucose Oxidase to Nanostructured Films of Polystyrene-block-poly(2-vinylpyridine)

    OpenAIRE

    Bhakta, Samir A; Benavidez, Tomas E; Garcia, Carlos D

    2014-01-01

    A critical step for the development of biosensors is the immobilization of the biorecognition element to the surface of a substrate. Among other materials that can be used as substrates, block copolymers have the untapped potential to provide significant advantages for the immobilization of proteins. To explore such possibility, this manuscript describes the fabrication and characterization of thin-films of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP). These films were then used to inv...

  8. Fate factors and emission flux estimates for emerging contaminants in surface waters

    Directory of Open Access Journals (Sweden)

    Hoa T. Trinh

    2016-01-01

    Full Text Available Pharmaceuticals, personal care products, hormones, and wastewater products are emerging environmental concerns for manifold reasons, including the potential of some compounds found in these products for endocrine disruption at a very low chronic exposure level. The environmental occurrences and sources of these contaminants in the water, soil, sediment and biota in European nations and the United States are well documented. This work reports a screening-level emission and fate assessment of thirty compounds, listed in the National Reconnaissance of the United States Geological Survey (USGS, 1999–2000 as the most frequently detected organic wastewater contaminants in U.S. streams and rivers. Estimations of the surface water fate factors were based on Level II and Level III multimedia fugacity models for a 1000 km2 model environment, the size of a typical county in the eastern United States. The compounds are categorized into three groups based upon the sensitivity of their predicted surface water fate factors to uncertainties in their physicochemical property values and the landscape parameters. The environmental fate factors, mass distributions, and loss pathways of all of the compounds are strongly affected by their assumed modes of entry into the environment. It is observed that for thirteen of the thirty organic wastewater contaminants most commonly detected in surface waters, conventional treatment strategies may be ineffective for their removal from wastewater effluents. The surface water fate factors predicted by the fugacity models were used in conjunction with the surface water concentrations measured in the USGS reconnaissance to obtain emission flux estimates for the compounds into U.S. streams and rivers. These include estimated fluxes of 6.8 × 10−5 to 0.30 kg/h km2 for the biomarker coprostanol; 1.7 × 10−5 to 6.5 × 10−5 kg/h km2 for the insect repellent N,N-diethyltoluamide; and 4.3 × 10−6 to 3.1 × 10−5 kg/h km2 for

  9. The evaluation for usefulness of the custom made immobilization device for the anteroperitoneal resection patients with rectal cancer

    International Nuclear Information System (INIS)

    Yang, Oh Nam; Lee, Woo Seok; Hong, Tae Kyun; Jo, Young Pih; Yun, Hwa Ryong; Kim, Jung Man

    2003-01-01

    Patient immobilization is essential factor for successful radiation therapy and major problem is reproducibility to maintain patient position during total radiation therapy period. Purpose of this study is evaluation for usefulness of the custom made immobilization device for the anteroperitoneal resection patients with rectal cancer. The object of this study were patients who underwent anteroperitoneal resection and undergo radiation therapy at present with rectal cancer. We made immobilization device for patient individually and analyzed its set up reproducibility, patient position deviation and errors. There was 5 mm-10 mm deviation in patient position without individual immobilization device, but we improved the deviation within few mm limitation with individual immobilization device. Custom made immobilization device was very helpful for anteroperitoneal resection patient with rectal cancer. We improved the patient position deviation within few mm limitation, shorten the set up time and we could give the comfort to patients.

  10. Shoe and field surface risk factors for acute lower extremity injuries among female youth soccer players

    Science.gov (United States)

    O'Kane, John W.; Gray, Kristen E.; Levy, Marni R.; Neradilek, Moni; Tencer, Allan F.; Polissar, Nayak L.; Schiff, Melissa A.

    2015-01-01

    Objective Describe acute lower extremity injuries and evaluate extrinsic risk factors in female youth soccer Design Nested case-control study Setting Youth soccer clubs in Washington State, USA. Participants Female soccer players (N= 351) ages 11 to 15 years randomly selected from 4 soccer clubs from which 83% of their players were enrolled with complete follow-up for 92% of players. Interventions Injured players were interviewed regarding injury, field surface, shoe type, and position. Uninjured controls, matched on game or practice session, were also interviewed. Main Outcome Measures The association between risk factors and acute lower extremity injury using logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI). Results One hundred seventy-three acute lower extremity injuries occurred involving primarily the ankle (39.3%), knee (24.9%), and thigh (11.0%). Over half (52.9%) recovered within 1 week, while 30.2% lasted beyond 2 weeks. During practices, those injured were approximately 3-fold ( OR 2.83, 95% CI 1.49-5.31) more likely to play on grass than artificial turf and 2.4-fold (95% CI 1.03-5.96) more likely to wear cleats on grass than other shoe and surface combinations. During games injured players were 89% (95% CI 1.03-4.17) more likely to play defender compared to forward. Conclusions Half of the acute lower extremity injuries affected the ankle or knee. Grass surface and wearing cleats on grass increased training injuries. PMID:26327288

  11. Limonene inhibits streptococcal biofilm formation by targeting surface-associated virulence factors.

    Science.gov (United States)

    Subramenium, Ganapathy Ashwinkumar; Vijayakumar, Karuppiah; Pandian, Shunmugiah Karutha

    2015-08-01

    The present study explores the efficacy of limonene, a cyclic terpene found in the rind of citrus fruits, for antibiofilm potential against species of the genus Streptococcus, which have been deeply studied worldwide owing to their multiple pathogenic efficacy. Limonene showed a concentration-dependent reduction in the biofilm formation of Streptococcus pyogenes (SF370), with minimal biofilm inhibitory concentration (MBIC) of 400 μg ml - 1. Limonene was found to possess about 75-95 % antibiofilm activity against all the pathogens tested, viz. Streptococcus pyogenes (SF370 and 5 clinical isolates), Streptococcus mutans (UA159) and Streptococcus mitis (ATCC 6249) at 400 μg ml - 1 concentration. Microscopic analysis of biofilm architecture revealed a quantitative breach in biofilm formation. Results of a surface-coating assay suggested that the possible mode of action of limonene could be by inhibiting bacterial adhesion to surfaces, thereby preventing the biofilm formation cascade. Susceptibility of limonene-treated Streptococcus pyogenes to healthy human blood goes in unison with gene expression studies in which the mga gene was found to be downregulated. Anti-cariogenic efficacy of limonene against Streptococcus mutans was confirmed, with inhibition of acid production and downregulation of the vicR gene. Downregulation of the covR, mga and vicR genes, which play a critical role in regulating surface-associated proteins in Streptococcus pyogenes and Streptococcus mutans, respectively, is yet further evidence to show that limonene targets surface-associated proteins. The results of physiological assays and gene expression studies clearly show that the surface-associated antagonistic mechanism of limonene also reduces surface-mediated virulence factors.

  12. [Factors related to the influence on congenital malformation of body surface in Shaanxi province].

    Science.gov (United States)

    Ying, J; Lei, Q; Qin, B W; Qu, P F; Lei, F L; Dang, S N; Zeng, L X; Yan, H

    2016-12-10

    Objective: To investigate the influencing factors on congenital malformation of body surface. Methods: Multi-stage stratified random sampling method was adopted. A questionnaire survey was conducted among the childbearing aged women who experienced more than 28 weeks pregnancy or having definite pregnancy outcomes in Shaanxi, during 2010-2013. Results: Results from the logistic regression model showed that factors as: intrahepatic cholestasis of pregnancy ( OR =21.76, 95 %CI : 4.46-106.25), histories with abnormal pregnancy or reproduction ( OR =11.88, 95 %CI : 9.14-15.45), having birth defects in the family ( OR =6.15, 95 %CI : 2.66-14.23), being twins ( OR =5.74, 95 % CI : 3.34-9.86), being worker (compared with others, OR =2.47, 95 % CI : 1.30-4.68) or farmer (compared with others, OR =1.91, 95 %CI : 1.14-3.20), less than 4 times of antenatal care (compared with >7, OR =1.84, 95 % CI : 1.28-2.64), occupational exposure to related risks during pregnancy ( OR =1.74, 95 % CI : 1.26-2.42), mother's hometown was from mid-part of Shaanxi (compared with northern Shaanxi, OR =1.65, 95 %CI : 1.20-2.28), mother's native residence was from the rural areas ( OR =1.75, 95 % CI : 1.13-2.71), drug use ( OR =1.64, 95 % CI : 1.26-2.13) etc . were risk factors for congenital malformation of body surface. Iron supplement during pregnancy ( OR =0.46, 95 %CI : 0.21-0.99) appeared as protective factor for congenital malformation of body surface. Conclusion: The following factors seemed to be of risk for congenital malformation of body surface, including: mother's native area was from the middle part of Shaanxi and living in rural area, being worker or farmer, histories of abnormal pregnancy and reproduction, history of birth defects in the family, being twins, with antenatal care less than 4 times, occupational exposure to dangerous materials, drug use, intrahepatic cholestasis during pregnancy etc .

  13. Herbaceous plants as filters: Immobilization of particulates along urban street corridors

    International Nuclear Information System (INIS)

    Weber, Frauke; Kowarik, Ingo; Säumel, Ina

    2014-01-01

    Among air pollutants, particulate matter (PM) is considered to be the most serious threat to human health. Plants provide ecosystem services in urban areas, including reducing levels of PM by providing a surface for deposition and immobilization. While previous studies have mostly addressed woody species, we focus on herbaceous roadside vegetation and assess the role of species traits such as leaf surface roughness or hairiness for the immobilization of PM. We found that PM deposition patterns on plant surfaces reflect site-specific traffic densities and that strong differences in particulate deposition are present among species. The amount of immobilized PM differed according to particle type and size and was related to specific plant species traits. Our study suggests that herbaceous vegetation immobilizes a significant amount of the air pollutants relevant to human health and that increasing biodiversity of roadside vegetation supports air filtration and thus healthier conditions along street corridors. -- Highlights: • We assessed PM immobilization by common urban herbaceous roadside species. • PM deposition was related to traffic density and plant species traits. • Amount of PM deposited differed according to particle type and size. • Increasing biodiversity of roadside vegetation supports air filtration. -- Herbaceous urban roadside vegetation immobilizes particulate matter relevant to human health, thus supporting healthier conditions next to busy roads

  14. Glucose oxidase immobilization onto carbon nanotube networking

    International Nuclear Information System (INIS)

    Karachevtsev, V.A.; Glamazda, A.Yu.; Zarudnev, E.S.; Karachevtsev, M.V.; Leontiev, V.S.; Linnik, A.S.; Plokhotnichenko, A.M.; Stepanian, S.G.; Lytvyn, O.S.

    2012-01-01

    The efficient immobilization of GOX onto a carbon nanotube network through the molecular interface formed by PSE is carried out. This conclusion is based on the analysis of AFM images of the network with the adsorbed enzyme, whose globules locate mainly along a nanotube. The band corresponding to the high-frequency component of the G mode in the RR spectrum of the nanotube with adsorbed PSE is downshifted by 0.7 cm -1 relative to this band in the spectrum of pristine nanotubes. The analysis of the intensities of bands assigned to the RBM of nanotubes with adsorbed PSE in comparison with the spectrum of pristine SWNTs revealed the intensity transformation, which can be explained by a change of the resonance condition with variation of the laser energy. Thus, we concluded that PSE molecules create nanohybrids with SWNTs, which ensures the further enzyme immobilization. As the RR spectrum of an SWNT:PSE:GOX film does not essentially differ from SWNT:PSE ones, this indicates that the molecular interface (PSE) isolates the enzyme from nanotubes strongly enough. Our studies on the conductive properties of a single walled carbon nanotube network sprayed onto a quartz substrate from a solution of nanotubes in dichlorobenzene demonstrated that the I(U) dependence has nonlinear character. Most likely, the nonlinearity is related to Schottky barriers, which originate on the contact between nanotubes and the gold electrode, as well as between nanotubes with different conductivities. The deposition of bioorganic compounds (PSE and GOX) on the carbon nanotube network is accompanied by a decrease of their conductivity. Most probably, such a decrease is caused by adsorbed PSE molecules, which induce the appearance of scattering centers for charge carriers on the nanotube surface. The following GOX adsorption has practically no effect on the conductivity of the nanotube network that evidences the reliable isolation of the nanotube surface from the enzyme by means of the molecular

  15. Mechanical Q-factor measurements on a test mass with a structured surface

    Energy Technology Data Exchange (ETDEWEB)

    Nawrodt, R [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Zimmer, A [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Koettig, T [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Clausnitzer, T [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Bunkowski, A [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Kley, E B [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Schnabel, R [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Danzmann, K [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Nietzsche, S [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Vodel, W [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Tuennermann, A [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Seidel, P [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany)

    2007-07-15

    We present mechanical Q-factors (quality factors) of a crystalline quartz test mass with a nano-structured surface, measured in the temperature regime from 5 to 300 K. The nano-structure was a grating with a period of 2 {mu}m and a depth of about 0.1 {mu}m. Comparative measurements were performed on the plain substrate and on the structured test mass with different numbers of SiO{sub 2}/Ta{sub 2}O{sub 5} coating layers. The measurements at different stages of the test mass fabrication process show that the surface distortion induced by the nanostructure does not severely lower the mechanical Q-factor of the substrate. Damping due to a multi-layer coating stack was found to be orders of magnitude higher. The results provide vital information concerning the potential usage of low-thermal noise nano-structured test masses in future generations of high-precision laser interferometers and in current attempts to measure quantum effects of macroscopic mirror oscillators.

  16. Immobilization of radioactive strontium in contaminated soils by phosphate treatment

    International Nuclear Information System (INIS)

    Kim, K.H.; Ammons, J.T.

    1990-01-01

    The feasibility of in situ phosphate- and metal- (calcium, aluminum, and iron) solution treatment for 90 Sr immobilization was investigated. Batch and column experiments were performed to find optimum conditions for coprecipitation of 90 Sr with Ca-, Al-, and Fe-phosphate compounds in contaminated soils. Separate columns were packed with artificially 85 Sr-contaminated acid soil as well as 90 Sr-contaminated soil from the Oak Ridge Reservation. After metal-phosphate treatment, the columns were then leached successively with either tapwater or 0.001 M CaCl 2 solution. Most of the 85 Sr coprecipitated with the metal phosphate compounds. Immobilization of 85 Sr and 90 Sr was affected by such factors as solution pH, metal and phosphate concentration, metal-to-phosphate ratio, and soil characteristics. Equilibration time after treatments also affected 85 Sr immobilization. Many technology aspects still need to be investigated before field applications are feasible, but these experiments indicate that phosphate-based in situ immobilization should prevent groundwater contamination and will be useful as a treatment technology for 90 Sr-contaminated sites. 15 refs., 3 figs., 1 tab

  17. A simple gold nanoparticle-mediated immobilization method to fabricate highly homogeneous DNA microarrays having higher capacities than those prepared by using conventional techniques

    International Nuclear Information System (INIS)

    Jung, Cheulhee; Mun, Hyo Young; Li, Taihua; Park, Hyun Gyu

    2009-01-01

    A simple, highly efficient immobilization method to fabricate DNA microarrays, that utilizes gold nanoparticles as the mediator, has been developed. The fabrication method begins with electrostatic attachment of amine-modified DNA to gold nanoparticles. The resulting gold-DNA complexes are immobilized on conventional amine or aldehyde functionalized glass slides. By employing gold nanoparticles as the immobilization mediator, implementation of this procedure yields highly homogeneous microarrays that have higher binding capacities than those produced by conventional methods. This outcome is due to the increased three-dimensional immobilization surface provided by the gold nanoparticles as well as the intrinsic effects of gold on emission properties. This novel immobilization strategy gives microarrays that produce more intense hybridization signals for the complementary DNA. Furthermore, the silver enhancement technique, made possible only in the case of immobilized gold nanoparticles on the microarrays, enables simple monitoring of the integrity of the immobilized DNA probe.

  18. Properties of immobilized papain by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, Minoru; Kaetsu, Isao

    1984-01-01

    Papain was immobilized by the radiation polymerization of various monomers at low temperatures and the effects of the polymer matrix on the enzyme activity and thermal stability of the immobilized enzymes were studied. The activity of the immobilized enzymes prepared from monofunctional (acrylate and methacrylate) monomers was higher than that from bifunctional (bismethacrylate) monomers and that from polyoxyethylene dimethacrylate monomers increased with an increase in the number of oxyethylene units. The thermal stability of the immobilized enzymes prepared from hydrophilic monomers was higher than that from hydrophobic monomers and increased markedly with increasing monomer concentration. (author)

  19. Preliminary assessment of modified borosilicate glasses for chromium and ruthenium immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Farid, Osama M. [Reactors Department, Nuclear Research Center, Atomic Energy Authority of Egypt, P.O. 13759, Inshas, Cairo (Egypt); Centre of Nuclear Engineering (CNE), Department of Materials, Imperial College London, London, SW7 2BP (United Kingdom); Abdel Rahman, R.O., E-mail: alaarehab@yahoo.com [Hot Laboratory Center, Atomic Energy Authority of Egypt, P.O. 13759, Inshas, Cairo (Egypt)

    2017-01-15

    The feasibility of using modified alkali borosilicate glasses for ruthenium and chromium immobilization is preliminary assessed by investigating the immobilization system structure under normal conditions. Within this context, reference alkali borosilicate, and simulated Magnox-modified glasses were prepared and studied. The results indicate that ruthenium is immobilized in the vitreous structure as encapsulated RuO{sub 2} crystallites that act as seeds for heterogeneous nucleation of other crystalline phases. The presence of Zn, as modifier, has contributed to chromium immobilization in zincochromite spinel structure, whereas Ca is accommodated in the vitreous structure. Immobilization performance was evaluated by conducting conservative static leach test and studying the leached glass. Leached glass morphology was altered, where near surface reference glass is leached over 400 nm and simulated Magnox-modified sample is altered over 300 nm. Normalized release rates are within normal range for borosilicate material. For simulated Magnox-modified sample, Ca and alkali structural element, i.e. Na and Li, are leached via ion-exchange reaction. The ion-exchanged fraction equals 1.06 × 10{sup −8} mol/m{sup 2} s and chromium has slightly lower normalized release rate value than ruthenium. - Highlights: • The presence of modifiers and waste oxides led to localized de-vitrification. • Ruthenium is encapsulated within the vitreous glass network as RuO{sub 2} crystals. • Chromium is immobilized within the zincochromite spinel structure. • Pitting and cracks induced by leaching did not affect the immobilization performance.

  20. Visible and UV-curable chitosan derivatives for immobilization of biomolecules.

    Science.gov (United States)

    Kim, Eun-Hye; Han, Ga-Dug; Kim, Jae-Won; Noh, Seung-Hyun; Lee, Jae-Gwan; Ito, Yoshihiro; Son, Tae-Il

    2017-11-01

    Chitosan, which has many biocompatible properties, is used widely in medical field like wound healing, drug delivery and so on. Chitosan could be used as a biomaterial to immobilize protein-drug. There are many methods to immobilize protein-drug, but they have some drawbacks such as low efficiency and denaturation of protein. Therefore, photo-immobilization method is suggested to immobilize protein-drug. Photo-immobilization method is simple-reaction and also needs no additional crosslinking reagent. There has been some effort to modify chitosan to have an ability of photo-immobilization. Generally, visible and UV light reactive chitosan derivatives were prepared. Various types of photo-curable chitosan derivatives showed possibility for application to medical field. For example, they showed ability for protein-immobilization and some of them showed wound-healing effect, anti-adhesive effect, or property to interact directly with titanium surface. In this study, we introduce many types of photo-curable chitosan derivative and their possibility of medical application. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Antibody immobilized on Fe3O4 particles and its application to RIAs

    International Nuclear Information System (INIS)

    Shen Rongsen; Xing Ruiyun

    1997-01-01

    A magnetic particle second antibody (MSA-I) was prepared by means of immobilizing donkey anti-rabbit antiserum on Fe 3 O 4 particles 10.8 nm +- 34% in diameter. Effects of some factors, such as pH of buffer used for immobilizing antiserum, amount of antiserum, time of immobilizing antiserum and blocking buffer on specific and nonspecific binding of MSA-I in RIAs were studied. The MSA-I was successfully applied to RIAs of T 3 , T 4 and TSH. The advantages of the magnetic second antibody were simplicity and time-saving in preparation and low cost

  2. Management of primary anterior shoulder dislocations using immobilization.

    Science.gov (United States)

    Smith, Brent I; Bliven, Kellie C Huxel; Morway, Genoveffa R; Hurbanek, Jason G

    2015-05-01

    identified 2083 articles. A total of 9 studies met all of the criteria and were included in this review. In most of the studies, age was a risk factor for recurrence. Patients less than 30 years of age were more likely to sustain a recurrent dislocation than patients more than 30 years of age. In 5 studies (n = 1215), researchers found no difference in recurrence of shoulder dislocation when immobilized in internal rotation (IR) for less than 1 week (41%, 40 of 97) compared with more than 3 weeks (37%, 34 of 93) in patients less than 30 years of age (P = .52). Authors of 3 studies (n = 289) compared the effect of immobilization in IR versus external rotation (ER), and whereas they found no statistical difference, a trend appeared toward reduced recurrence rates in ER but not IR (P = .07). The rate of recurrent dislocation was 40% (25 of 63) in patients treated with IR sling immobilization and 25% (22 of 88) in patients immobilized in ER. Overall, the investigators found that younger age (immobilization for more than 1 week did not improve recurrence rates, and an apparent trend existed toward decreased recurrence rates with ER rather than IR. According to the review and meta-analysis by Paterson et al, the level of evidence for recommendations regarding optimal duration and position of immobilization to reduce the risk of recurrent dislocation was therapeutic level II. This level of evidence was appropriate because the review included only prospective studies of level I or II and a minimum follow-up of 1 year.

  3. Shielding Factors for Gamma Radiation from Activity Deposited on Structures and Ground Surfaces

    DEFF Research Database (Denmark)

    Jensen, Per Hedemann

    1985-01-01

    A computer model DEPSHIELD for the calculation of shielding factors for gamma radiation at indoor residences in multistorey and single-family houses has been developed. The model is based on the exponential point kernel that links the radiation flux density at a given detector point to a point...... it possible to determine the dose reduction effect from a decontamination of the different surfaces. The model has been used in a study of the consequences of land contamination of Danish territory after hypothetical core-melt accidents at the Barseback nuclear power plant in Sweden. The model has also been...

  4. Root caries, root surface restorations and lifestyle factors in adult Danes

    DEFF Research Database (Denmark)

    Christensen, Lisa Bøge; Bardow, Allan; Ekstrand, Kim

    2015-01-01

    , tobacco use and oral hygiene routines were collected from 4369 adults aged 21-89 who took part in a survey covering 13 municipalities across Denmark. Uni- and multivariate logistic regression analyses were applied to analyse the relationship between the independent lifestyle variables and active caries...... consumption, as well as wearing dentures, were significantly associated with the occurrence of untreated caries and restored root surface lesions, especially in persons over 45. Thus, such lifestyle factors should be taken into consideration, identifying persons with a need of preventive dental services...

  5. Dependence of protein binding capacity of dimethylamino-γ-butyric-acid (DMGABA)-immobilized porous membrane on composition of solvent used for DMGABA immobilization

    International Nuclear Information System (INIS)

    Iwanade, Akio; Umeno, Daisuke; Saito, Kyoichi; Sugo, Takanobu

    2013-01-01

    Dimethylamino-γ-butyric acid (DMGABA) as an ampholite was reacted with the epoxy group of the poly-glycidyl methacrylate chain grafted onto the pore surface of a porous hollow-fiber polyethylene membrane by radiation-induced graft polymerization. DMGABA was dissolved in a mixture of dioxane and water at various dioxane volume fractions, defined by dividing the dioxane volume by the total volume. The equilibrium binding capacity (EBC) of the DMGABA-immobilized porous hollow-fiber membrane for lysozyme was evaluated in the permeation mode. The EBC was varied from a 1/50-fold monolayer binding capacity to a 10-fold monolayer binding capacity by controlling the composition of the solvent used for DMGABA immobilization and the molar conversion of the epoxy group into the DMGABA group. - Highlights: ► A DMGABA membrane was immobilized by irradiation induced graft polymerization. ► The DMGABA was immobilized in a mixture of dioxane and water of various compositions. ► Lysozyme adsorptivity of DMGABA-immobilized membranes evaluated in the permeation mode. ► The composition of the DMGABA immobilized solvent can control adsorptivity

  6. Recent Developments in the Site-Specific Immobilization of Proteins onto Solid Supports

    Energy Technology Data Exchange (ETDEWEB)

    Camarero, J A

    2007-02-21

    Immobilization of proteins onto surfaces is of great importance in numerous applications, including protein analysis, drug screening, and medical diagnostics, among others. The success of all these technologies relies on the immobilization technique employed to attach a protein to the corresponding surface. Non-specific physical adsorption or chemical cross-linking with appropriate surfaces results in the immobilization of the protein in random orientations. Site-specific covalent attachment, on the other hand, leads to molecules being arranged in a definite, orderly fashion and allows the use of spacers and linkers to help minimize steric hindrances between the protein and the surface. The present work reviews the latest chemical and biochemical developments for the site-specific covalent attachment of proteins onto solid supports.

  7. Development of phage/antibody immobilized magnetostrictive biosensors

    Science.gov (United States)

    Fu, Liling

    There is an urgent need for biosensors that are able to detect and quantify the presence of a small amount of pathogens in a real-time manner accurately and quickly to guide prevention efforts and assay food and water quality. Acoustic wave (AW) devices, whose performance is defined by mass sensitivity (Sm) and quality factor (Q value), have been extensively studied as high performance biosensor platforms. However, current AW devices still face some challenges such as the difficulty to be employed in liquid and low Q value in practical applications. The objective of this research is to develop magnetostrictive sensors which include milli/microcantilever type (MSMC) and particle type (MSP). Compared to other AW devices, MSMC exhibits the following advantages: (1) wireless/remote driving and sensing; (2) easy to fabricate; (3) works well in liquid; (4) exhibits a high Q value (> 500 in air). The fundamental study of the damping effect on MSMCs from the surrounding media including air and liquids were conducted to improve the Q value of MSMCs. The experiment results show that the Q value is dependent on the properties of surrounding media (e.g. viscosity, density), the geometry of the MSMCs, and the harmonic mode on the resonance behavior of MSMCs, etc. The phage-coated MSMC has high specificity and sensitivity even while used in water with a low concentration of targeted bacteria. Two currently developed phages, JRB7 and E2, respectively respond to Bacillus anthracis spores and Salmonella typhimurium, were employed as bio-recognition elements in this research. The phage-immobilized MSMC biosensors exhibited high performance and detection of limit was 5 x 104 cfu/ml for the MSMC in size of 1.4 x 0.8 x 0.035 mm. The MSMC-based biosensors were indicated as a very potential method for in-situ monitoring of the biological quality in water. The MSP combine antibody was used to detect Staphylococcus aureus in this experiment. The interface between MSPs and antibody was

  8. Trends in interfacial design for surface plasmon resonance based immunoassays

    International Nuclear Information System (INIS)

    Shankaran, Dhesingh Ravi; Miura, Norio

    2007-01-01

    Immunosensors based on surface plasmon resonance (SPR) have become a promising tool in sensor technology for biomedical, food, environmental, industrial and homeland security applications. SPR is a surface sensitive optical technique, suitable for real-time and label-free analysis of biorecognition events at functional transducer surfaces. Fabrication of highly active and robust sensing surfaces is an important part in immunoassays because the quality, quantity, chemistry and topography of the interfacial biomembranes play a major role in immunosensor performance. Eventually, a variety of immobilization methods such as physical adsorption, covalent coupling, Langmuir-Blodgett film, polymer thin film, self-assembly, sol-gel, etc, have been introduced over the years for the immobilization of biomolecules (antibody or antigen) on the transducer surfaces. The selection of an immobilization method for an immunoassay is governed by several factors such as nature and stability of the biomolecules, target analyte, application, detection principle, mode of signal transduction, matrix complexity, etc. This paper provides an overview of the various surface modification methods for SPR based immunosensor fabrication. The preparation, structure and application of different functional interfacial surfaces have been discussed along with a brief introduction to the SPR technology, biomolecules and detection principles. (review article)

  9. Trends in interfacial design for surface plasmon resonance based immunoassays

    Energy Technology Data Exchange (ETDEWEB)

    Shankaran, Dhesingh Ravi [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka, 816-8580 (Japan); Miura, Norio [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka, 816-8580 (Japan)

    2007-12-07

    Immunosensors based on surface plasmon resonance (SPR) have become a promising tool in sensor technology for biomedical, food, environmental, industrial and homeland security applications. SPR is a surface sensitive optical technique, suitable for real-time and label-free analysis of biorecognition events at functional transducer surfaces. Fabrication of highly active and robust sensing surfaces is an important part in immunoassays because the quality, quantity, chemistry and topography of the interfacial biomembranes play a major role in immunosensor performance. Eventually, a variety of immobilization methods such as physical adsorption, covalent coupling, Langmuir-Blodgett film, polymer thin film, self-assembly, sol-gel, etc, have been introduced over the years for the immobilization of biomolecules (antibody or antigen) on the transducer surfaces. The selection of an immobilization method for an immunoassay is governed by several factors such as nature and stability of the biomolecules, target analyte, application, detection principle, mode of signal transduction, matrix complexity, etc. This paper provides an overview of the various surface modification methods for SPR based immunosensor fabrication. The preparation, structure and application of different functional interfacial surfaces have been discussed along with a brief introduction to the SPR technology, biomolecules and detection principles. (review article)

  10. Surface water acidification and critical loads: exploring the F-factor

    Directory of Open Access Journals (Sweden)

    K. Bishop

    2009-11-01

    Full Text Available As acid deposition decreases, uncertainties in methods for calculating critical loads become more important when judgements have to be made about whether or not further emission reductions are needed. An important aspect of one type of model that has been used to calculate surface water critical loads is the empirical F-factor which estimates the degree to which acid deposition is neutralised before it reaches a lake at any particular point in time relative to the pre-industrial, steady-state water chemistry conditions.

    In this paper we will examine how well the empirical F-functions are able to estimate pre-industrial lake chemistry as lake chemistry changes during different phases of acidification and recovery. To accomplish this, we use the dynamic, process-oriented biogeochemical model SAFE to generate a plausible time series of annual runoff chemistry for ca. 140 Swedish catchments between 1800 and 2100. These annual hydrochemistry data are then used to generate empirical F-factors that are compared to the "actual" F-factor seen in the SAFE data for each lake and year in the time series. The dynamics of the F-factor as catchments acidify, and then recover are not widely recognised.

    Our results suggest that the F-factor approach worked best during the acidification phase when soil processes buffer incoming acidity. However, the empirical functions for estimating F from contemporary lake chemistry are not well suited to the recovery phase when the F-factor turns negative due to recovery processes in the soil. This happens when acid deposition has depleted the soil store of BC, and then acid deposition declines, reducing the leaching of base cations to levels below those in the pre-industrial era. An estimate of critical load from water chemistry during recovery and empirical F functions would therefore result in critical loads that are too low. Therefore, the empirical estimates of the F-factor are a significant source of

  11. Production of Biodiesel Using Immobilized Lipase and the Characterization of Different Co-Immobilizing Agents and Immobilization Methods

    Directory of Open Access Journals (Sweden)

    Kang Zhao

    2016-08-01

    Full Text Available Lipase from Candida sp. 99–125 is widely employed to catalyzed transesterification and can be used for biodiesel production. In this study, the lipase was immobilized by combined adsorption and entrapment to catalyze biodiesel production from waste cooking oil (WCO via transesterification, and investigating co-immobilizing agents as additives according to the enzyme activity. The addition of the mixed co-immobilizing agents has positive effects on the activities of the immobilized lipase. Three different immobilizing methods were compared by the conversion ratio of biodiesel and structured by Atom Force Microscopy (AFM and Scanning Electron Microscopy (SEM, respectively. It was found that entrapment followed by adsorption was the best method. The effect of the co-immobilizing agent amount, lipase dosage, water content, and reuse ability of the immobilized lipase was investigated. By comparison with previous research, this immobilized lipase showed good reuse ability: the conversion ratio excesses 70% after 10 subsequent reactions, in particular, was better than Novozym435 and TLIM on waste cooking oil for one unit of lipase.

  12. Development of new Z-factors for the evaluation of the circumferential surface crack in nuclear pipes

    International Nuclear Information System (INIS)

    Choi, Y.H.; Chung, Y.K.; Park, Y.W.; Lee, J.B.

    1997-01-01

    The purpose of this study is to develop new Z-factors to evaluate the behavior of a circumferential surface crack in nuclear pipe. Z-factor is a load multiplier used in the Z-factor method, which is one of the ASME Code Sec. XI's recommendations for the estimation of a surface crack in nuclear pipe. It has been reported that the load carrying capacities predicted from the current ASME Code Z-factors, are not well in agreement with the experimental results for nuclear pipes with a surface crack. In this study, new Z-factors for ferritic base metal, ferritic submerged arc welding (SAW) weld metal, austenitic base metal, and austenitic SAW weld metal are obtained by use of the surface crack for thin pipe (SC.TNP) method based on GE/EPRI method. The desirability of both the SC.TNP method and the new Z-factors is examined using the results from 48 pipe fracture experiments for nuclear pipes with a circumferential surface crack. The results show that the SC.TNP method is good for describing the circumferential surface crack behavior and the new Z-factors are well in agreement with the measured Z-factors for both ferritic and austenitic pipes. (orig.)

  13. EPDIM peptide-immobilized porous chitosan beads for enhanced wound healing: Preparation, characterizations and in vitro evaluation

    International Nuclear Information System (INIS)

    Bae, Jin Woo; Lee, Joon Hye; Choi, Won Sup; Lee, Dong Sin; Bae, Eun Hee; Park, Ki Dong

    2009-01-01

    EPDIM peptide is known to regulate cellular activities by interacting with α 3 β 1 integrin, which can be contributed to wound healing process. In this study, EPDIM was immobilized onto three-dimensional porous chitosan beads (χtopore) as a scaffold for enhanced wound healing. The significant decrease in contact angle indicates that EPDIM immobilization could lead to the enhanced surface wettability after its immobilization. The immobilized EPDIM was fairly distributed along its surface and the morphology was maintained even after the reaction. The immobilized amount of EPDIM was found to be about 5.68 nmol/mg of χtopore by amino acid analysis. To verify the complete removal of coupling agents after EPDIM immobilization, each coupling agent was quantitatively analyzed by LC-MS. In vitro proliferation rates of both NIH 3T3 and HaCaT showed that EPDIM immobilization onto χtopore could significantly enhance the growth rate of both cells, while the unmodified χtopore did not increase in cell number even after 15 days of culture. Therefore, these results demonstrate that EPDIM peptide-immobilized χtopore can be utilized as an attractive scaffold for enhanced wound healing.

  14. Plasma Rich in Growth Factors for the Treatment of Ocular Surface Diseases.

    Science.gov (United States)

    Anitua, Eduardo; Muruzabal, Francisco; de la Fuente, María; Merayo, Jesús; Durán, Juan; Orive, Gorka

    2016-07-01

    The purpose of this work is to describe and review the technology of plasma rich in growth factors (PRGF), a novel blood derivative product, in the treatment of ocular surface disorders. To demonstrate the importance of this technology in the treatment of ocular pathologies, a thorough review of the preclinical and clinical literature results obtained following use of the different therapeutic formulations of PRGF was carried out. A literature search for applications of PGRF plasma in the ophthalmology field was carried out using the PubMed database. PRGF involves the use of patient's own biologically active proteins, growth factors, and biomaterial scaffolds for therapeutic purposes. This procedural technology is gaining interest in regenerative medicine due to its potential to stimulate and accelerate the tissue healing processes. The versatility and biocompatibility of this technology opens the door to a personalized medicine on ocular tissue regeneration. This review discusses the state of the art of the new treatments and technologies developed to promote ocular surface tissue regeneration. The standardized protocol that has been developed to source eye drops from PRGF technology is also described. The preclinical research, together with the most relevant clinical applications are summarized and discussed. The preliminary results suggest that the use of PRGF to enhance ocular tissue regeneration is safe and efficient.

  15. Factors Influencing NO2 Adsorption/Reduction on Microporous Activated Carbon: Porosity vs. Surface Chemistry

    Directory of Open Access Journals (Sweden)

    Imen Ghouma

    2018-04-01

    Full Text Available The textural properties and surface chemistry of different activated carbons, prepared by the chemical activation of olive stones, have been investigated in order to gain insight on the NO2 adsorption mechanism. The parent chemical activated carbon was prepared by the impregnation of olive stones in phosphoric acid followed by thermal carbonization. Then, the textural properties and surface chemistry were modified by chemical treatments including nitric acid, sodium hydroxide and/or a thermal treatment at 900 °C. The main properties of the parent and modified activated carbons were analyzed by N2-adsorption, scanning electron microscopy (SEM, and Fourier transform infrared spectroscopy (FTIR techniques, in order to enlighten the modifications issued from the chemical and thermal treatments. The NO2 adsorption capacities of the different activated carbons were measured in fixed bed experiments under 500 ppmv NO2 concentrations at room temperature. Temperature programmed desorption (TPD was applied after adsorption tests in order to quantify the amount of the physisorbed and chemisorbed NO2. The obtained results showed that the development of microporosity, the presence of oxygen-free sites, and the presence of basic surface groups are key factors for the efficient adsorption of NO2.

  16. Comparison of four supports for adsorption of reactive dyes by immobilized Aspergillus fumigatus beads

    Institute of Scientific and Technical Information of China (English)

    WANG Bao-e; HU Yong-you

    2007-01-01

    Four materials, sodium carboxymethylcellulose (Na-CMC), sodium alginate (SA), polyvinyl alcohol (PVA), and chitosan (CTS), were prepared as supports for entrapping fungus Aspergillus fumigatus. The adsorption of synthetic dyes, reactive brilliant blue KN-R, and reactive brilliant red K-2BP, by these immobilized gel beads and plain gel beads was evaluated. The adsorption efficiencies of reactive brilliant red K-2BP and reactive brilliant blue KN-R by CTS immobilized beads were 89.1% and 93.5% in 12 h, respectively. The adsorption efficiency by Na-CMC immobilized beads was slightly lower than that of mycelial pellets. But the dye culture mediums were almost completely decolorized in 48 h using the above-mentioned two immobilized beads (exceeding 95%). The adsorption efficiency by SA immobilized beads exceeded 92% in 48 h. PVA-SA immobilized beads showed the lowest adsorption efficiency, which was 79.8% for reactive brilliant red K-2BP and 92.5% for reactive brilliant blue KN-R in 48 h. Comparing the adsorption efficiency by plain gel beads, Na-CMC plain gel beads ranked next to CTS ones. SA and PVA-SA plain gel beads hardly had the ability of adsorbing dyes. Subsequently, the growth of mycelia in Na-CMC and SA immobilized beads were evaluated. The biomass increased continuously in 72 h. The adsorption capacity of reactive brilliant red K-2BP and reactive brilliant blue KN-R by Na-CMC immobilized beads was 78.0 and 86.7 mg/g, respectively. The SEM micrographs show that the surface structure of Na-CMC immobilized bead is loose and finely porous, which facilitates diffusion of the dyes.

  17. Technetium Immobilization Forms Literature Survey

    Energy Technology Data Exchange (ETDEWEB)

    Westsik, Joseph H.; Cantrell, Kirk J.; Serne, R. Jeffrey; Qafoku, Nikolla

    2014-05-01

    Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.

  18. Matrix metalloproteinase 9 (MMP-9) mediated release of MMP-9 resistant stromal cell-derived factor 1α (SDF-1α) from surface modified polymer films.

    Science.gov (United States)

    Steinhagen, Max; Hoffmeister, Peter-Georg; Nordsieck, Karoline; Hötzel, Rudi; Baumann, Lars; Hacker, Michael C; Schulz-Siegmund, Michaela; Beck-Sickinger, Annette G

    2014-04-23

    Preparation of smart materials by coatings of established surfaces with biomolecules will lead to the next generation of functionalized biomaterials. Rejection of implants is still a major problem in medical applications but masking the implant material with protein coatings is a promising approach. These layers not only disguise the material but also equip it with a certain biological function. The anti-inflammatory chemokine stromal cell-derived factor 1α (SDF-1α) is well suited to take over this function, because it efficiently attracts stem cells and promotes their differentiation and proliferation. At least the initial stem cell homing requires the formation of a concentration gradient. Thus, a reliable and robust release mechanism of SDF-1α from the material is essential. Several proteases, most notably matrix metalloproteinases, are upregulated during inflammation, which, in principle, can be exploited for a tightly controlled release of SDF-1α. Herein, we present the covalent immobilization of M-[S4V]-SDF-1α on novel biodegradable polymer films, which consist of heterobifunctional poly(ethylene glycol) and oligolactide-based functionalized macromers. A peptidic linker with a trimeric matrix metalloproteinase 9 (MMP-9) cleavage site (MCS) was used as connection and the linkage between the three components was achieved by combination of expressed protein ligation and Cu(I) catalyzed azide/alkyne cycloaddition. The MCS was used for MMP-9 mediated release of M-[S4V]-SDF-1α from the biomaterial and the released SDF-1α derivative was biologically active and induced strong cell migration, which demonstrates the great potential of this system.

  19. Hyaluronan Immobilized Polyurethane as a Blood Contacting Material

    Directory of Open Access Journals (Sweden)

    Feirong Gong

    2010-01-01

    Full Text Available Hyaluronan (hyaluronic acid, HA was immobilized onto the surface of amino-functionalized polyurethane films with the goal of obtaining a novel kind of biomaterial which had the potential in blood-contacting applications. The amino-functionalized polyurethane was prepared by synthesized acidic polyurethane whose pendant carboxyl groups were treated with an excess amount of 1,3-diaminopropane in the presence of N,N-carbonyldiimidazole (CDI. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR, Raman spectroscopy (RS, scanning electron microscopy (SEM, and water contact angle measurement were used to confirm the surface changes at each step of treatment, both in morphologies and chemical compositions. APTT and PT results showed that HA immobilization could prolong the blood coagulation time, thus HA-immobilized polyurethane (PU-HA exhibited improved blood compatibility. Cytotoxicity analysis showed that the PU-HA films synthesized in this study were cytocompatible and could support human vein endothelial cells (HUVECs adhesion and proliferation.

  20. Graphene oxide immobilized enzymes show high thermal and solvent stability

    Czech Academy of Sciences Publication Activity Database

    Hermanová, S.; Zarevúcka, Marie; Bouša, D.; Pumera, M.; Sofer, Z.

    2015-01-01

    Roč. 7, č. 13 (2015), s. 5852-5858 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-09001S Grant - others:GA AV ČR(CZ) M200551203 Institutional support: RVO:61388963 Keywords : graphene oxide * lipase * immobilization Subject RIV: CC - Organic Chemistry Impact factor: 7.760, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/nr/c5nr00438a

  1. Plutonium Immobilization Project Binder Burnout and Sintering Studies (Milestone 6.6a)

    International Nuclear Information System (INIS)

    Chandler, G.

    1999-01-01

    The Plutonium Immobilization Team has developed an integrated test program to understand and optimize the controlling variables for the sintering step of the plutonium immobilization process. Sintering is the key process step that controls the product mineralogy. It is expected that the sintering will be the limiting process step that controls the throughput of the production line. The goal of the current sintering test program is to better understand