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  STATE OF THE ART AND FUTURE TECHNICAL POSSIBILITIES FOR THE MEASUREMENT OF BIOLOGICAL PARAMETERS (ESP. IN VIVO)

  Liess, H.-D.; Pfeiffer, U. J.; Universität der Bundeswehr München, Fachbereich Elektrotechnik, D-8014 Neubiberg, FRG; Technische Universität München, Institut für Experimentelle Chirurgie, D-8000 München, FRG (GBF Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, 1989)

  In recent years progress in the area of semiconductor technology, whichis the result of the high degree of miniaturization, has led to new technologies and new applications in the related fields of physical, chemical, and biological sensing mechanisms. Typically for this trend in medical diagnostics is the shift from the in-vitro analysis to in-vivo determination of chemical and biological parameters by the replacement of the chemical analytic methods by chemical sensors. As far as physical parameters in biomedicine are concerned new applications are being considered. In order to avoid any contamination and degradation during transportation future systems under consideration might determine all the parameters ofinterest directly in the organism. The sensing area will become small enough to receive analytical data from a volume downto the cell order of magnitude.
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  SOLID POTENTIOMETRIC PH-ELECTRODE

  Kreuer, Klaus-Dieter; CONDUCTA GmbH + Co, Dieselstr. 24, D-7016 Gerlingen Max Planck Institute for Solids Research Heisenbergstr. 1, D-7000 Stuttgart 80 (GBF Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, 1989)

  Potentiometric pH-glass electrodes are among the most reliable so far known. Most remaining disadvantages (e.g. limited operating temperature, minimum size) stem from their aqueous component (reference buffer). The purpose of this investigation is therefore to maintain glass as a menbrane with outstandingly good sensing properties but to replace the reference buffer, including the Ag/AgCl electrode, by a solid contact providing a reversible transition from the ionic to the electronic part of the sensor The problems in making such a contact are discussed in terms of thermodynamic and kinetic parameters. The properties of glass electrodes contacted with the materials belonging to the Li, Ag, I ternary system are presented. They are compared with those of conventional pH-electrodes and pH-FETs. The advantages arising from the chemical stability of the contact with the glass membrane are outlined.
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  ENZYME SENSORS FOR BIOTECHNOLOGICAL PROCESSES AND PRODUCTS

  Renneberg, R.; Trott-Kriegeskorte, G.; Pawlowa, Mariana; Kaiser, G.; Warsinke, A.; Schmid, Rolf D.; Scheller, Frieder; Zentralinstitut fir Molekularbiologie der Akademie der Wissenschaften der DDR, 1100 Berlin-Buch, DDR *Gesellschaft fir Biotechnologische Forschung, 3300 Braunschweig, BRD (GBF Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, 1989)

  Enzyme sensors have been developed usina coupled enzyme reactions to determine the concentrations of the biotechnoloay products starch, pullulan, oligosaccharides. maltose. the low-calorie sweetener maltitol. glutamine, and enzyme activities of alpha-amylase and pullulanase. These enzyme sensors have been tested to control enzyme production by immobilized cells and also animal tissue cultures.
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  Biosensors for On-Line Monitoring of the Waterways and for Sample Taking Aimed at Relieving Disturbances

  Hansen, P.-D.; Pluta, H.-J.; Beeken, J. A.; Institute for Water, Soil and Air Hygiene of the Federal Health Office Corrensplatz 1, 1000 Berlin 33, FRG *Technische Universitat Berlin, FB 14 - Fachgebiet Limnologie-aquatische Ökotoxikologie; Universität Bayreuth, Fachgebiet Ökochemie (GBF Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, 1989)

  Organismic and suborganismic testing methods are well suited as biological warning systems (biosensors) which build a sensitive system used in screening for hazardous substances. Although chemo-physical testing methods can never detect and identify all polluting chemicals in the environment to the fullest extent, biological early warning systems make it possible to monitor dangerous substances or groups of substances in waterways. Electrodes made up of cyanobacteria, i.e. Synechococcus, for immediate detection of acute toxic effects, are used as a biological early warning system for recognizing damage to the waterways. The so-called “cyanobacterial electrodes” are graphite electrodes (see Figure 1) which have cyanobacteria, i.e. Synechococcus, affixed to them. The measurements of the photosynthetic electron transport system, PET, under alternating light - dark conditions, are conducted in a flow-through cell against reference electrodes (Ag/AgCl).. A mediator (Fe II / Fe III) makes the flow of current possible by becoming reduced by these bacteria and then reoxidized at the working electrode. The time which the electrode takes to react is about two minutes, and a multiple confirmed result is available after ten minutes. The detection limits for the individual substances have been set according to the results obtained up to present at less than 10 Ug per litre for atrazine and at 100 ug per litre for linuron (see Table 1).
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  LaxWO3 - Perovskite: A New Sensor Material for the Potentiometric Detection of Dissolved Oxygen

  Kohler, Heinz; CONDUCTA GmbH&Co., Dieselstr. 24, 7016 Gerlingen Institut fiir Physikalische und Theoretische Chemie Auf der Morgenstelle 8, 7400 Tiibingen F.R.G. (GBF Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, 1989)

  The suitability of the La,WO3 -perovskites as electrode materials for potentiometric measurements of dissolved oxygen at room temperature or below is demonstrated by EMF data of a Lag 2WO3 ceramics. A model of potential formation is presented which explains the observed dependency of the EMF on the concentration of dissolved oxygen as well as on the solution acidity and on [WO,42-].

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