TY - JOUR A1 - Huck, Christina A1 - Schiffels, Johannes A1 - Herrera, Cony N. A1 - Schelden, Maximilian A1 - Selmer, Thorsten A1 - Poghossian, Arshak A1 - Baumann, Marcus A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Metabolic responses of Escherichia coli upon glucose pulses captured by a capacitive field-effect sensor JF - Physica Status Solidi (A) N2 - Living cells are complex biological systems transforming metabolites taken up from the surrounding medium. Monitoring the responses of such cells to certain substrate concentrations is a challenging task and offers possibilities to gain insight into the vitality of a community influenced by the growth environment. Cell-based sensors represent a promising platform for monitoring the metabolic activity and thus, the “welfare” of relevant organisms. In the present study, metabolic responses of the model bacterium Escherichia coli in suspension, layered onto a capacitive field-effect structure, were examined to pulses of glucose in the concentration range between 0.05 and 2 mM. It was found that acidification of the surrounding medium takes place immediately after glucose addition and follows Michaelis–Menten kinetic behavior as a function of the glucose concentration. In future, the presented setup can, therefore, be used to study substrate specificities on the enzymatic level and may as well be used to perform investigations of more complex metabolic responses. Conclusions and perspectives highlighting this system are discussed. Y1 - 2013 U6 - https://doi.org/10.1002/pssa.201200900 SN - 0031-8965 VL - 210 IS - 5 SP - 926 EP - 931 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Tran, Thanh Ngoc A1 - Staat, Manfred T1 - An Edge-Based Smoothed Finite Element Method for Primal-Dual Shakedown Analysis of Structures Under Uncertainties JF - Limit State of Materials and Structures : Direct Methods 2. Saxcé, Géry de (Hrsg.) Y1 - 2013 SN - 978-94-007-5424-9 SP - 89 EP - 102 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Thiel, Alexander A1 - Tippkötter, Nils A1 - Suck, Kirstin A1 - Sohling, Ulrich A1 - Ruf, Friedrich A1 - Ulber, Roland T1 - New zeolite adsorbents for downstream processing of polyphenols from renewable resources JF - Engineering in Life Sciences N2 - Commercial materials with polyvinylpolypyrrolidone and polymeric amberlites (XAD7HP, XAD16) are commonly used for the adsorptive downstream processing of polyphenols from renewable resources. In this study, beta-zeolite-based adsorbent systems were examined, and their properties were compared to organic resins. Batch adsorption experiments were conducted with synthetic solutions of major polyphenols. Adsorption isotherms and desorption characteristics of individual adsorbent were determined based on these results. Maximum adsorption capacities were calculated using the Langmuir model. For example, the zeolites had capacities up to 203.2 mg/g for ferulic acid. To extend these results to a complex system, additional experiments were performed on rapeseed meal and wheat seed extracts as representative renewable resources. HPLC analysis showed that with 7.5% w/v, which is regarded as the optimum amount of zeolites, zeolites A and B could bind 100% of the major polyphenols as well as release polyphenols at high yields. Additionally, regeneration experiments were performed with isopropyl alcohol at 99°C to evaluate how zeolites regenerate under mild conditions. The results showed only a negligible loss of adsorption capacity and no loss of desorption capacity. In summary, it was concluded that beta-zeolites were promising adsorbents for developing new processes to isolate polyphenols from renewable resources. Y1 - 2013 U6 - https://doi.org/10.1002/elsc.201200188 VL - 13 IS - 3 SP - 239 EP - 246 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Staat, Manfred T1 - Limit and shakedown analysis under uncertainty JF - International journal of computational methods : IJCM Y1 - 2013 SN - 0219-8762 SP - Publ. online PB - World Scientific Publishing CY - Singapore ER - TY - JOUR A1 - Poghossian, Arshak A1 - Weil, M. A1 - Cherstvy, A. G. A1 - Schöning, Michael Josef T1 - Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices JF - Analytical and bioanalytical chemistry N2 - The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte–insulator–semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance–voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed. Y1 - 2013 U6 - https://doi.org/10.1007/s00216-013-6951-9 SN - 1432-1130 ; 1618-2642 VL - 405 IS - 20 SP - 6425 EP - 6436 PB - Springer CY - Berlin ER - TY - CHAP A1 - Niemüller, Tim A1 - Lakemeyer, Gerhard A1 - Ferrein, Alexander T1 - Aspects of integrating diverse software into robotic systems extended abstract T2 - ICRA 2013 - 8th Workshop on Software Development and Integration in Robotics (SDIR), Karlsruhe, Germany Y1 - 2013 SP - 1 EP - 2 ER - TY - JOUR A1 - Laack, Walter van A1 - Levers, A. A1 - Staat, Manfred T1 - Gonarthrosetherapie auf Kernspinresonanzbasis mit MBST-Vierjahresbeobachtungen JF - Orthopädische Nachrichten : Zeitung für Orthopädie und Unfallchirurgie. 2013, H. 7/8 Y1 - 2013 SN - 1437-2193 SP - 13 PB - Biermann CY - Köln ER - TY - JOUR A1 - Kramer, Friederike A1 - Halamkova, Lenka A1 - Poghossian, Arshak A1 - Schöning, Michael Josef A1 - Katz, Evgeny A1 - Halamek, Jan T1 - Biocatalytic analysis of biomarkers for forensic identification of ethnicity between Caucasian and African American JF - The analyst. August 2013 Y1 - 2013 SN - 1364-5528 (E-Journal); 0003-2654 (Print) VL - Vol. 138 SP - 6251 EP - 6257 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Bäcker, Matthias A1 - Rakowski, D. A1 - Poghossian, Arshak A1 - Biselli, Manfred A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Chip-based amperometric enzyme sensor system for monitoring of bioprocesses by flow-injection analysis JF - Journal of Biotechnology N2 - A microfluidic chip integrating amperometric enzyme sensors for the detection of glucose, glutamate and glutamine in cell-culture fermentation processes has been developed. The enzymes glucose oxidase, glutamate oxidase and glutaminase were immobilized by means of cross-linking with glutaraldehyde on platinum thin-film electrodes integrated within a microfluidic channel. The biosensor chip was coupled to a flow-injection analysis system for electrochemical characterization of the sensors. The sensors have been characterized in terms of sensitivity, linear working range and detection limit. The sensitivity evaluated from the respective peak areas was 1.47, 3.68 and 0.28 μAs/mM for the glucose, glutamate and glutamine sensor, respectively. The calibration curves were linear up to a concentration of 20 mM glucose and glutamine and up to 10 mM for glutamate. The lower detection limit amounted to be 0.05 mM for the glucose and glutamate sensor, respectively, and 0.1 mM for the glutamine sensor. Experiments in cell-culture medium have demonstrated a good correlation between the glutamate, glutamine and glucose concentrations measured with the chip-based biosensors in a differential-mode and the commercially available instrumentation. The obtained results demonstrate the feasibility of the realized microfluidic biosensor chip for monitoring of bioprocesses. Y1 - 2013 U6 - https://doi.org/10.1016/j.jbiotec.2012.03.014 SN - 0168-1656 VL - 163 IS - 4 SP - 371 EP - 376 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bäcker, Matthias A1 - Schusser, Sebastian A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Degradationsverhalten bioabbaubarer Polymere : siliziumbasierte Sensorik zur Überwachung JF - GIT Labor-Fachzeitschrift Y1 - 2013 SN - 0016-3538 SP - 32 EP - 33 PB - Wiley-VCH CY - Weinheim ER -