@inproceedings{TakenagaHerreraWerneretal.2013, author = {Takenaga, Shoko and Herrera, Cony F. and Werner, Frederik and Biselli, Manfred and Schnitzler, Thomas and Sch{\"o}ning, Michael Josef and {\"O}hlschl{\"a}ger, Peter and Wagner, Torsten}, title = {Detection of the metabolic activity of cells by differential measurements based on a single light-addressable potentiometric sensor chip}, series = {11. Dresdner Sensor-Symposium : 9.-11.12.2013}, booktitle = {11. Dresdner Sensor-Symposium : 9.-11.12.2013}, organization = {Dresdner Sensor-Symposium <11, 2013>}, isbn = {978-3-9813484-5-3}, pages = {63 -- 67}, year = {2013}, language = {en} } @article{HuckSchiffelsHerreraetal.2013, author = {Huck, Christina and Schiffels, Johannes and Herrera, Cony N. and Schelden, Maximilian and Selmer, Thorsten and Poghossian, Arshak and Baumann, Marcus and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {Metabolic responses of Escherichia coli upon glucose pulses captured by a capacitive field-effect sensor}, series = {Physica Status Solidi (A)}, volume = {210}, journal = {Physica Status Solidi (A)}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0031-8965}, doi = {10.1002/pssa.201200900}, pages = {926 -- 931}, year = {2013}, abstract = {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.}, language = {en} } @article{WernerGroebelKrumbeetal.2012, author = {Werner, Frederik and Groebel, Simone and Krumbe, Christoph and Wagner, Torsten and Selmer, Thorsten and Yoshinobu, Tatsuo and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Nutrient concentration-sensitive microorganism-based biosensor}, series = {Physica Status Solidi (a)}, volume = {209}, journal = {Physica Status Solidi (a)}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201100801}, pages = {900 -- 904}, year = {2012}, language = {en} } @article{BaeckerRaueSchusseretal.2012, author = {B{\"a}cker, Matthias and Raue, Markus and Schusser, Sebastian and Jeitner, C. and Breuer, L. and Wagner, P. and Poghossian, Arshak and F{\"o}rster, Arnold and Mang, Thomas and Sch{\"o}ning, Michael Josef}, title = {Microfluidic chip with integrated microvalves based on temperature- and pH-responsive hydrogel thin films}, series = {Physica Status Solidi (a)}, volume = {209}, journal = {Physica Status Solidi (a)}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201100763}, pages = {839 -- 845}, year = {2012}, abstract = {Two types of microvalves based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) and pH-responsive poly(sodium acrylate) (PSA) hydrogel films have been developed and tested. The PNIPAAm and PSA hydrogel films were prepared by means of in situ photopolymerization directly inside the fluidic channel of a microfluidic chip fabricated by combining Si and SU-8 technologies. The swelling/shrinking properties and height changes of the PNIPAAm and PSA films inside the fluidic channel were studied at temperatures of deionized water from 14 to 36 °C and different pH values (pH 3-12) of Titrisol buffer, respectively. Additionally, in separate experiments, the lower critical solution temperature (LCST) of the PNIPAAm hydrogel was investigated by means of a differential scanning calorimetry (DSC) and a surface plasmon resonance (SPR) method. Mass-flow measurements have shown the feasibility of the prepared hydrogel films to work as an on-chip integrated temperature- or pH-responsive microvalve capable to switch the flow channel on/off.}, 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{BaeckerDellePoghossianetal.2011, author = {B{\"a}cker, Matthias and Delle, L. and Poghossian, Arshak and Biselli, Manfred and Zang, Werner and Wagner, P. and Sch{\"o}ning, Michael Josef}, title = {Electrochemical sensor array for bioprocess monitoring}, series = {Electrochimica Acta (2011)}, volume = {56}, journal = {Electrochimica Acta (2011)}, number = {26}, publisher = {Elsevier}, address = {Amsterdam}, pages = {9673 -- 9678}, year = {2011}, language = {en} } @article{WernerKrumbeSchumacheretal.2011, author = {Werner, Frederik and Krumbe, Christoph and Schumacher, Katharina and Groebel, Simone and Spelthahn, Heiko and Stellberg, Michael and Wagner, Torsten and Yoshinobu, Tatsuo and Selmer, Thorsten and Keusgen, Michael and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor}, series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, journal = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, publisher = {Wiley}, address = {Weinheim}, isbn = {1862-6319}, pages = {1340 -- 1344}, year = {2011}, language = {en} } @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{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{WagnerMolinaYoshinobuetal.2007, author = {Wagner, Torsten and Molina, Roberto and Yoshinobu, Tatsuo and Kloock, Joachim P. and Biselli, Manfred and Canzoneri, Michele and Schnitzler, Thomas and Sch{\"o}ning, Michael Josef}, title = {Handheld multi-channel LAPS device as a transducer platform for possible biological and chemical multi-sensor applications}, series = {Electrochimica Acta. 53 (2007), H. 2}, journal = {Electrochimica Acta. 53 (2007), H. 2}, isbn = {0013-4686}, pages = {305 -- 311}, year = {2007}, language = {en} }