TY - JOUR A1 - Welden, Melanie A1 - Severins, Robin A1 - Poghossian, Arshak A1 - Wege, Christina A1 - Bongaerts, Johannes A1 - Siegert, Petra A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor JF - Chemosensors N2 - Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte–insulator–semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716ᵀ is immobilized via biotin–streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage–current, capacitance–voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution. Y1 - 2022 U6 - http://dx.doi.org/10.3390/chemosensors10060218 SN - 2227-9040 N1 - This article belongs to the Special Issue "Nanostructured Devices for Biochemical Sensing" VL - 10 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Molinnus, Denise A1 - Bäcker, Matthias A1 - Siegert, Petra A1 - Willenberg, H. A1 - Poghossian, Arshak A1 - Keusgen, M. A1 - Schöning, Michael Josef T1 - Detection of Adrenaline Based on Substrate Recycling Amplification JF - Procedia Engineering N2 - An amperometric enzyme biosensor has been applied for the detection of adrenaline. The adrenaline biosensor has been prepared by modification of an oxygen electrode with the enzyme laccase that operates at a broad pH range between pH 3.5 to pH 8. The enzyme molecules were immobilized via cross-linking with glutaraldehyde. The sensitivity of the developed adrenaline biosensor in different pH buffer solutions has been studied. Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.proeng.2015.08.708 SN - 1877-7058 N1 - Eurosensors 2015 VL - 120 SP - 540 EP - 543 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Takenaga, Shoko A1 - Herrera, Cony F. A1 - Werner, Frederik A1 - Biselli, Manfred A1 - Schnitzler, Thomas A1 - Schöning, Michael Josef A1 - Öhlschläger, Peter A1 - Wagner, Torsten T1 - Detection of the metabolic activity of cells by differential measurements based on a single light-addressable potentiometric sensor chip T2 - 11. Dresdner Sensor-Symposium : 9.-11.12.2013 Y1 - 2013 SN - 978-3-9813484-5-3 SP - 63 EP - 67 ER - TY - JOUR A1 - Werner, Frederik A1 - Krumbe, Christoph A1 - Schumacher, Katharina A1 - Groebel, Simone A1 - Spelthahn, Heiko A1 - Stellberg, Michael A1 - Wagner, Torsten A1 - Yoshinobu, Tatsuo A1 - Selmer, Thorsten A1 - Keusgen, Michael A1 - Baumann, Marcus A1 - Schöning, Michael Josef T1 - Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor JF - Physica status solidi (a) : applications and material science. 208 (2011), H. 6 Y1 - 2011 SN - 1862-6319 SP - 1340 EP - 1344 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Molinnus, Denise A1 - Muschallik, Lukas A1 - Gonzalez, Laura Osorio A1 - Bongaerts, Johannes A1 - Wagner, Torsten A1 - Selmer, Thorsten A1 - Siegert, Petra A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Development and characterization of a field-effect biosensor for the detection of acetoin JF - Biosensors and Bioelectronics N2 - A capacitive electrolyte-insulator-semiconductor (EIS) field-effect biosensor for acetoin detection has been presented for the first time. The EIS sensor consists of a layer structure of Al/p-Si/SiO₂/Ta₂O₅/enzyme acetoin reductase. The enzyme, also referred to as butane-2,3-diol dehydrogenase from B. clausii DSM 8716T, has been recently characterized. The enzyme catalyzes the (R)-specific reduction of racemic acetoin to (R,R)- and meso-butane-2,3-diol, respectively. Two different enzyme immobilization strategies (cross-linking by using glutaraldehyde and adsorption) have been studied. Typical biosensor parameters such as optimal pH working range, sensitivity, hysteresis, linear concentration range and long-term stability have been examined by means of constant-capacitance (ConCap) mode measurements. Furthermore, preliminary experiments have been successfully carried out for the detection of acetoin in diluted white wine samples. Y1 - 2018 U6 - http://dx.doi.org/10.1016/j.bios.2018.05.023 VL - 115 SP - 1 EP - 6 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Turek, Monika A1 - Ketterer, Lothar A1 - Claßen, Melanie A1 - Berndt, Heinz A1 - Elbers, Gereon A1 - Krüger, Peter A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Development and Electrochemical Investigations of an EIS-(Electrolyte-Insulator-Semiconductor) based Biosensor for Cyanide Detection JF - Sensors Y1 - 2007 SN - 1424-8220 VL - 7 IS - 8 SP - 1415 EP - 1426 ER - TY - JOUR A1 - Pilas, Johanna A1 - Iken, Heiko A1 - Selmer, Thorsten A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Development of a multi‐parameter sensor chip for the simultaneous detection of organic compounds in biogas processes JF - Physica status solidi (a) N2 - An enzyme-based multi-parameter biosensor is developed for monitoring the concentration of formate, d-lactate, and l-lactate in biological samples. The sensor is based on the specific dehydrogenation by an oxidized β-nicotinamide adenine dinucleotide (NAD+)-dependent dehydrogenase (formate dehydrogenase, d-lactic dehydrogenase, and l-lactic dehydrogenase, respectively) in combination with a diaphorase from Clostridium kluyveri (EC 1.8.1.4). The enzymes are immobilized on a platinum working electrode by cross-linking with glutaraldehyde (GA). The principle of the determination scheme in case of l-lactate is as follows: l-lactic dehydrogenase (l-LDH) converts l-lactate into pyruvate by reaction with NAD+. In the presence of hexacyanoferrate(III), the resulting reduced β-nicotinamide adenine dinucleotide (NADH) is then regenerated enzymatically by diaphorase. The electrochemical detection is based on the current generated by oxidation of hexacyanoferrate(II) at an applied potential of +0.3 V vs. an Ag/AgCl reference electrode. The biosensor will be electrochemically characterized in terms of linear working range and sensitivity. Additionally, the successful practical application of the sensor is demonstrated in an extract from maize silage. Y1 - 2015 U6 - http://dx.doi.org/10.1002/pssa.201431894 SN - 1862-6319 VL - 212 IS - 6 SP - 1306 EP - 1312 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Röhlen, Desiree A1 - Pilas, Johanna A1 - Schöning, Michael Josef A1 - Selmer, Thorsten T1 - Development of an amperometric biosensor platform for the combined determination of l-Malic, Fumaric, and l-Aspartic acid JF - Applied Biochemistry and Biotechnology N2 - Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD+) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM−1 (L-malate biosensor) and 0.4 μA mM−1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0–10.0 mM with a sensitivity of 0.09 μA mM−1. The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates. Y1 - 2017 U6 - http://dx.doi.org/10.1007/s12010-017-2578-1 SN - 1559-0291 VL - 183 SP - 566 EP - 581 PB - Springer CY - Berlin ER - TY - JOUR A1 - Bäcker, Matthias A1 - Delle, L. A1 - Poghossian, Arshak A1 - Biselli, Manfred A1 - Zang, Werner A1 - Wagner, P. A1 - Schöning, Michael Josef T1 - Electrochemical sensor array for bioprocess monitoring JF - Electrochimica Acta (2011) Y1 - 2011 VL - 56 IS - 26 SP - 9673 EP - 9678 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Takenaga, Shoko A1 - Schneider, Benno A1 - Erbay, E. A1 - Biselli, Manfred A1 - Schnitzler, Thomas A1 - Schöning, Michael Josef A1 - Wagner, Torsten T1 - Fabrication of biocompatible lab-on-chip devices for biomedical applications by means of a 3D-printing process JF - Physica status solidi (a) N2 - A new microfluidic assembly method for semiconductor-based biosensors using 3D-printing technologies was proposed for a rapid and cost-efficient design of new sensor systems. The microfluidic unit is designed and printed by a 3D-printer in just a few hours and assembled on a light-addressable potentiometric sensor (LAPS) chip using a photo resin. The cell growth curves obtained from culturing cells within microfluidics-based LAPS systems were compared with cell growth curves in cell culture flasks to examine biocompatibility of the 3D-printed chips. Furthermore, an optimal cell culturing within microfluidics-based LAPS chips was achieved by adjusting the fetal calf serum concentrations of the cell culture medium, an important factor for the cell proliferation. Y1 - 2015 U6 - http://dx.doi.org/10.1002/pssa.201532053 SN - 1862-6319 VL - 212 IS - 6 SP - 1347 EP - 1352 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Wagner, Torsten A1 - Molina, Roberto A1 - Yoshinobu, Tatsuo A1 - Kloock, Joachim P. A1 - Biselli, Manfred A1 - Canzoneri, Michele A1 - Schnitzler, Thomas A1 - Schöning, Michael Josef T1 - Handheld multi-channel LAPS device as a transducer platform for possible biological and chemical multi-sensor applications JF - Electrochimica Acta. 53 (2007), H. 2 Y1 - 2007 SN - 0013-4686 SP - 305 EP - 311 ER - TY - JOUR A1 - Breuer, Lars A1 - Raue, Markus A1 - Strobel, M. A1 - Mang, Thomas A1 - Schöning, Michael Josef A1 - Thoelen, R. A1 - Wagner, Torsten T1 - Hydrogels with incorporated graphene oxide as light-addressable actuator materials for cell culture environments in lab-on-chip systems JF - Physica status solidi (a) N2 - Abstractauthoren Graphene oxide (GO) nanoparticles were incorporated in temperature-sensitive Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels. The nanoparticles increase the light absorption and convert light energy into heat efficiently. Thus, the hydrogels with GO can be stimulated spatially resolved by illumination as it was demonstrated by IR thermography. The temporal progression of the temperature maximum was detected for different concentrations of GO within the polymer network. Furthermore, the compatibility of PNIPAAm hydrogels with GO and cell cultures was investigated. For this purpose, culture medium was incubated with hydrogels containing GO and the viability and morphology of chinese hamster ovary (CHO) cells was examined after several days of culturing in presence of this medium. Y1 - 2016 U6 - http://dx.doi.org/10.1002/pssa.201533056 SN - 1862-6300 VL - 213 IS - 6 SP - 1520 EP - 1525 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Breuer, Lars A1 - Mang, Thomas A1 - Schöning, Michael Josef A1 - Thoelen, Ronald A1 - Wagner, Torsten T1 - Investigation of the spatial resolution of a laser-based stimulation process for light-addressable hydrogels with incorporated graphene oxide by means of IR thermography JF - Sensors and Actuators A: Physical Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.sna.2017.11.031 SN - 0924-4247 VL - 268 SP - 126 EP - 132 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Welden, Rene A1 - Jablonski, Melanie A1 - Wege, Christina A1 - Keusgen, Michael A1 - Wagner, Patrick Hermann A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase JF - Biosensors N2 - The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte’s pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS. KW - microfluidics KW - enzyme kinetics KW - actuator-sensor system KW - light-addressable electrode KW - light-addressable potentiometric sensor Y1 - 2021 U6 - http://dx.doi.org/10.3390/bios11060171 SN - 2079-6374 N1 - This article belongs to the Special Issue "Selected Papers from the 1st International Electronic Conference on Biosensors (IECB 2020)" VL - 11 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Breuer, Lars A1 - Raue, Markus A1 - Kirschbaum, M. A1 - Mang, Thomas A1 - Schöning, Michael Josef A1 - Thoelen, R. A1 - Wagner, Torsten T1 - Light-controllable polymeric material based on temperature-sensitive hydrogels with incorporated graphene oxide JF - Physica status solidi (a) N2 - Poly(N-isopropylacrylamide) (PNIPAAm) hydrogel films with incorporated graphene oxide (GO) were developed and tested as light-stimulated actuators. GO dispersions were synthesized via Hummers method and characterized toward their optical properties and photothermal energy conversion. The hydrogels were prepared by means of photopolymerization. In addition, the influence of GO within the hydrogel network on the lower critical solution temperature (LCST) was investigated by differential scanning calorimetry (DSC). The optical absorbance and the response to illumination were determined as a function of GO concentration for thin hydrogel films. A proof of principle for the stimulation with light was performed. Y1 - 2015 U6 - http://dx.doi.org/10.1002/pssa.201431944 SN - 1862-6319 VL - 212 IS - 6 SP - 1368 EP - 1374 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Breuer, Lars A1 - Raue, Markus A1 - Mang, Thomas A1 - Schöning, Michael Josef A1 - Thoelen, Ronald A1 - Wagner, Torsten T1 - Light-stimulated hydrogel actuators with incorporated graphene oxide for microfluidic applications T2 - 12. Dresdner Sensor-Symposium 2015 Y1 - 2015 U6 - http://dx.doi.org/10.5162/12dss2015/P5.8 SP - 206 EP - 209 ER - 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 - http://dx.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 - Bäcker, Matthias A1 - Raue, Markus A1 - Schusser, Sebastian A1 - Jeitner, C. A1 - Breuer, L. A1 - Wagner, P. A1 - Poghossian, Arshak A1 - Förster, Arnold A1 - Mang, Thomas A1 - Schöning, Michael Josef T1 - Microfluidic chip with integrated microvalves based on temperature- and pH-responsive hydrogel thin films JF - Physica Status Solidi (a) N2 - 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. Y1 - 2012 U6 - http://dx.doi.org/10.1002/pssa.201100763 SN - 1862-6319 VL - 209 IS - 5 SP - 839 EP - 845 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Werner, Frederik A1 - Groebel, Simone A1 - Krumbe, Christoph A1 - Wagner, Torsten A1 - Selmer, Thorsten A1 - Yoshinobu, Tatsuo A1 - Baumann, Marcus A1 - Schöning, Michael Josef T1 - Nutrient concentration-sensitive microorganism-based biosensor JF - Physica Status Solidi (a) Y1 - 2012 U6 - http://dx.doi.org/10.1002/pssa.201100801 SN - 1862-6319 VL - 209 IS - 5 SP - 900 EP - 904 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Pilas, Johanna A1 - Yazici, Yasemen A1 - Selmer, Thorsten A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Optimization of an amperometric biosensor array for simultaneous measurement of ethanol, formate, d- and l-lactate JF - Electrochimica Acta N2 - The immobilization of NAD+-dependent dehydrogenases, in combination with a diaphorase, enables the facile development of multiparametric sensing devices. In this work, an amperometric biosensor array for simultaneous determination of ethanol, formate, d- and l-lactate is presented. Enzyme immobilization on platinum thin-film electrodes was realized by chemical cross-linking with glutaraldehyde. The optimization of the sensor performance was investigated with regard to enzyme loading, glutaraldehyde concentration, pH, cofactor concentration and temperature. Under optimal working conditions (potassium phosphate buffer with pH 7.5, 2.5 mmol L-1 NAD+, 2.0 mmol L-1 ferricyanide, 25 °C and 0.4% glutaraldehyde) the linear working range and sensitivity of the four sensor elements was improved. Simultaneous and cross-talk free measurements of four different metabolic parameters were performed successfully. The reliable analytical performance of the biosensor array was demonstrated by application in a clarified sample of inoculum sludge. Thereby, a promising approach for on-site monitoring of fermentation processes is provided. KW - Simultaneous determination KW - Enzymatic biosensor KW - Diaphorase KW - Dehydrogenase Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.electacta.2017.07.119 SN - 0013-4686 VL - 251 SP - 256 EP - 262 PB - Elsevier CY - Amsterdam ER -