Now showing 1 - 10 of 29
  • Publication
    Process optimization and biocompatibility of cell carriers suitable for automated magnetic manipulation
    ( 2012)
    Krejci, I.
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    Piana, C.
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    Howitz, S.
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    Wegener, T.
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    Fiedler, S.
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    Zwanzig, M.
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    Daum, N.
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    Meier, K.
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    Lehr, C.M.
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    Batista, U.
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    Zemljic, S.
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    Messerschmidt, J.
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    Franzke, J.
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    Wirth, M.
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    Gabor, F.
    There is increasing demand for automated cell reprogramming in the fields of cell biology, biotechnology and the biomedical sciences. Microfluidic-based platforms that provide unattended manipulation of adherent cells promise to be an appropriate basis for cell manipulation. In this study we developed a magnetically driven cell carrier to serve as a vehicle within an in vitro environment. To elucidate the impact of the carrier on cells, biocompatibility was estimated using the human adenocarcinoma cell line Caco-2. Besides evaluation of the quality of the magnetic carriers by field emission scanning electron microscopy, the rate of adherence, proliferation and differentiation of Caco-2 cells grown on the carriers was quantified. Moreover, the morphology of the cells was monitored by immunofluorescent staining. Early generations of the cell carrier suffered from release of cytotoxic nickel from the magnetic cushion. Biocompatibility was achieved by complete encapsulation of the nickel bulk within galvanic gold. The insulation process had to be developed stepwise and was controlled by parallel monitoring of the cell viability. The final carrier generation proved to be a proper support for cell manipulation, allowing proliferation of Caco-2 cells equal to that on glass or polystyrene as a reference for up to 10 days. Functional differentiation was enhanced by more than 30% compared with the reference. A flat, ferromagnetic and fully biocompatible carrier for cell manipulation was developed for application in microfluidic systems. Beyond that, this study offers advice for the development of magnetic cell carriers and the estimation of their biocompatibility.
  • Publication
    Der zerrissene Mensch und unser geteiltes Gedächtnis
    ( 2010)
    Kuschel, F.
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    Ringsdorf, H.
  • Publication
    Formation of new thermosets by the reaction of cyanates with thiophenols
    ( 2008)
    Bauer, M.
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    Bauer, J.
    Sulfur-containing aromatic thermosets, mainly consisting of aryloxy- and arylthio-substituted 1,3,5-triazines, have been prepared through the reaction of difunctional cyanates with mono- and difunctional aromatic thiols. A straightforward three-step reaction scheme is proposed and verified by the identification of key substances: (1) the addition of thiol and cyanate groups, (2) the stepwise addition of (thio)imino carbonic esters with one another, and (3) the ring closure of chain-extended (thio)imino carbonic esters to form 1,3,5-triazines. Reactions of types 2 and 3 are associated with an abstraction of phenol or thiophenol, which can enter into reaction 1 again. Characterization Of the curing behavior of dicyanate of bisphenol A with thiophenol as well as dimercaptodiphenyl sulfide by differential scanning calorimetry shows that the reaction rates are significantly enhanced by the admixture of thiols to the cyanate. Dynamic mechanical analysis of resulting thermosets showed that large amounts of comonomers can be incorporated into the network resulting in a decrease of glass temperature but increase of fracture toughness. Finally, the fully cured thermosets resulting front the reaction of dicyanate of bisphenol A with different admixtures of dimercaptodiphenyl sulfide were characterized by cone calorimetry to get information about flame retardancy. The flame retardancy is influenced by incorporation of dimercaptodiphenyl sulfide into the triazine network only slightly. .
  • Publication
    Automated 10-channel capillary chip immunodetector for biological agents detection
    ( 2007)
    Yacoub-George, E.
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    Hell, W.
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    Meixner, L.
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    Wenninger, F.
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    Bock, K.
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    Lindner, P.
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    Wolf, H.
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    Kloth, T.
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    Feller, K.A.
    The automated 10-channel capillary chip immunodetector (10K-IDWG) is a prototype, which has been developed for automatically operated biological agents (BA) point detection. The current technology uses a chemiluminescence capillary immunoassay (EIA) technique in combination with integrated microfluidics and allows the highly sensitive and rapid detection and preliminary identification of multiple BA in aqueous solutions in the laboratory. The chemiluminescence capillary EIA are performed within a disposable capillary chip containing 10 fused-silica capillaries arranged in parallel coated with selected capture antibodies. A multianode-photomultiplier array is used to detect chemiluminescence intensity in each capillary. Reservoirs for reagents and buffers and a waste disposal reservoir are integrated. This paper describes the technology of the 10K-IDWG and its evaluation with three different BA, the toxin staphylococcal enterotoxin B (SEB), the bacterial analyte Escherichia coli (E. coli) O157:H7 as a model for bacterial pathogens, and the bacteriophage M13 as a model for virus pathogens. The 10K-IDWG is able to detect the above mentioned three BA in an aqueous sample within 29 min (single analyte-detection and multiplexing). Limits of detection (LOD) are 0.1 ng/ml for SEB, 10(exp 4) cfu/ml for E. coli O157:H7, and 5 x 10(exp 5) pfu/ml for M13. Cross reactivities between the three assays were not observed.
  • Publication
    Fluidic bus system for chemical process engineering in the laboratory and for small-scale production
    ( 2005)
    Müller, A.
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    Cominos, V.
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    Hessel, V.
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    Horn, B.
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    Schürer, J.
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    Ziogas, A.
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    Jähnisch, K.
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    Hillmann, V.
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    Großer, V.
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    Jam, K.A.
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    Bazzanella, A.
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    Rinke, G.
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    Kraut, M.
    Within the framework of a BMBF-funded project, five research institutes are developing a standardized system for the combination of microstructured devices and laboratory equipment of various suppliers thus leading to the building of chemical plants. The concept is based upon the bus system and simultaneously handles a number of tasks such as mechanical stability, fluidic flow and signal transmission. A key feature of the backbone interface developed is its open architecture. It does not rely on standardized connections thus allowing the combination of devices from various suppliers. The interface shows robustness, withstands high pressures and temperatures while thermal cross-talk is minimized through the use of different materials. Its application in chemical synthesis has shown truly promising results.
  • Publication
    Application of variable-temperature ellipsometry to plasma polymers: The effect of addition of 1,7-octadiene to plasma deposits of acrylic-acid
    ( 2000)
    Haddow, D.B.
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    Goruppa, A.
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    Whittle, J.
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    Short, R.D.
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    Kahle, O.
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    Uhlig, C.
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    Bauer, M.
  • Publication
  • Publication
    Supramolecular architectures of cellulose derivatives
    ( 1997)
    Schulze, M.
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    Wegner, G.
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    Seufert, M.
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    Tebbe, H.
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    Buchholz, V.
  • Publication
    Kontinuierliche ortsaufgelöste HPLC auf Basis eines Multifunktionsventils
    ( 1997)
    Bauer, J.
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    Götze, H.-J.
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    Kiffmeyer, T.
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    Jursch, M.