@article{BaeckerBegingBisellietal.2009, author = {B{\"a}cker, Matthias and Beging, Stefan and Biselli, Manfred and Poghossian, Arshak and Wang, J. and Zang, Werner and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {Concept for a solid-state multi-parameter sensor system for cell-culture monitoring}, series = {Electrochimica Acta. 54 (2009), H. 25 Sp. Iss. SI}, journal = {Electrochimica Acta. 54 (2009), H. 25 Sp. Iss. SI}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0013-4686}, pages = {6107 -- 6112}, year = {2009}, language = {en} } @article{BaeckerRakowskiPoghossianetal.2013, author = {B{\"a}cker, Matthias and Rakowski, D. and Poghossian, Arshak and Biselli, Manfred and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {Chip-based amperometric enzyme sensor system for monitoring of bioprocesses by flow-injection analysis}, series = {Journal of Biotechnology}, volume = {163}, journal = {Journal of Biotechnology}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2012.03.014}, pages = {371 -- 376}, year = {2013}, abstract = {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.}, language = {en} } @article{JablonskiMuenstermannNorketal.2021, author = {Jablonski, Melanie and M{\"u}nstermann, Felix and Nork, Jasmina and Molinnus, Denise and Muschallik, Lukas and Bongaerts, Johannes and Wagner, Torsten and Keusgen, Michael and Siegert, Petra and Sch{\"o}ning, Michael Josef}, title = {Capacitive field-effect biosensor applied for the detection of acetoin in alcoholic beverages and fermentation broths}, series = {physica status solidi (a) applications and materials science}, volume = {218}, journal = {physica status solidi (a) applications and materials science}, number = {13}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.202000765}, pages = {7 Seiten}, year = {2021}, abstract = {An acetoin biosensor based on a capacitive electrolyte-insulator-semiconductor (EIS) structure modified with the enzyme acetoin reductase, also known as butane-2,3-diol dehydrogenase (Bacillus clausii DSM 8716ᵀ), is applied for acetoin detection in beer, red wine, and fermentation broth samples for the first time. The EIS sensor consists of an Al/p-Si/SiO₂/Ta₂O₅ layer structure with immobilized acetoin reductase on top of the Ta₂O₅ transducer layer by means of crosslinking via glutaraldehyde. The unmodified and enzyme-modified sensors are electrochemically characterized by means of leakage current, capacitance-voltage, and constant capacitance methods, respectively.}, language = {en} } @article{WernerGroebelSchuhmacheretal.2009, author = {Werner, Frederik and Groebel, Simone and Schuhmacher, K. and Spelthahn, Heiko and Wagner, Torsten and Selmer, Thorsten and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Bestimmung der metabolischen Aktivit{\"a}t von Mikroorganismen w{\"a}hrend des Biogasbildungsprozesses}, series = {9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]}, journal = {9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]}, publisher = {TUDpress}, address = {Dresden}, isbn = {978-3-941298-44-6}, pages = {201 -- 204}, year = {2009}, language = {de} } @article{PilasYaziciSelmeretal.2018, author = {Pilas, Johanna and Yazici, Y. and Selmer, Thorsten and Keusgen, M. and Sch{\"o}ning, Michael Josef}, title = {Application of a portable multi-analyte biosensor for organic acid determination in silage}, series = {Sensors}, volume = {18}, journal = {Sensors}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s18051470}, pages = {12 Seiten}, year = {2018}, abstract = {Multi-analyte biosensors may offer the opportunity to perform cost-effective and rapid analysis with reduced sample volume, as compared to electrochemical biosensing of each analyte individually. This work describes the development of an enzyme-based biosensor system for multi-parametric determination of four different organic acids. The biosensor array comprises five working electrodes for simultaneous sensing of ethanol, formate, d-lactate, and l-lactate, and an integrated counter electrode. Storage stability of the biosensor was evaluated under different conditions (stored at +4 °C in buffer solution and dry at -21 °C, +4 °C, and room temperature) over a period of 140 days. After repeated and regular application, the individual sensing electrodes exhibited the best stability when stored at -21 °C. Furthermore, measurements in silage samples (maize and sugarcane silage) were conducted with the portable biosensor system. Comparison with a conventional photometric technique demonstrated successful employment for rapid monitoring of complex media.}, language = {en} } @article{WagnerMolinaBisellietal.2007, author = {Wagner, Torsten and Molina, R. and Biselli, Manfred and Canzoneri, Michele and Schnitzler, Thomas and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef}, title = {A light-addressable potentiometric sensor system for fast, simultaneous and spatial detection of the metabolic activity of biological cells}, series = {Transducers '07 Eurosensors XXI : digest of technical papers ; the14th International Conference on Solid-State Sensors, Actuators and Microsystems, June 10-14, 2007, Lyon, France / Gilles Delapierre (Ed.)}, journal = {Transducers '07 Eurosensors XXI : digest of technical papers ; the14th International Conference on Solid-State Sensors, Actuators and Microsystems, June 10-14, 2007, Lyon, France / Gilles Delapierre (Ed.)}, publisher = {IEEE}, address = {Piscataway}, isbn = {1-4244-0841-5}, pages = {1107 -- 1110}, year = {2007}, language = {en} } @article{MuschallikMolinnusBongaertsetal.2017, author = {Muschallik, Lukas and Molinnus, Denise and Bongaerts, Johannes and Pohl, Martina and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Siegert, Petra and Selmer, Thorsten}, title = {(R,R)-Butane-2,3-diol Dehydrogenase from Bacillus clausii DSM 8716T: Cloning and Expression of the bdhA-Gene, and Initial Characterization of Enzyme}, series = {Journal of Biotechnology}, volume = {258}, journal = {Journal of Biotechnology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2017.07.020}, pages = {41 -- 50}, year = {2017}, abstract = {The gene encoding a putative (R,R)-butane-2,3-diol dehydrogenase (bdhA) from Bacillus clausii DSM 8716T was isolated, sequenced and expressed in Escherichia coli. The amino acid sequence of the encoded protein is only distantly related to previously studied enzymes (identity 33-43\%) and exhibited some uncharted peculiarities. An N-terminally StrepII-tagged enzyme variant was purified and initially characterized. The isolated enzyme catalyzed the (R)-specific oxidation of (R,R)- and meso-butane-2,3-diol to (R)- and (S)-acetoin with specific activities of 12 U/mg and 23 U/mg, respectively. Likewise, racemic acetoin was reduced with a specific activity of up to 115 U/mg yielding a mixture of (R,R)- and meso-butane-2,3-diol, while the enzyme reduced butane-2,3-dione (Vmax 74 U/mg) solely to (R,R)-butane-2,3-diol via (R)-acetoin. For these reactions only activity with the co-substrates NADH/NAD+ was observed. The enzyme accepted a selection of vicinal diketones, α-hydroxy ketones and vicinal diols as alternative substrates. Although the physiological function of the enzyme in B. clausii remains elusive, the data presented herein clearly demonstrates that the encoded enzyme is a genuine (R,R)-butane-2,3-diol dehydrogenase with potential for applications in biocatalysis and sensor development.}, language = {en} }