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  - Jablonski, Melanie
A1  - Münstermann, Felix
A1  - Nork, Jasmina
A1  - Molinnus, Denise
A1  - Muschallik, Lukas
A1  - Bongaerts, Johannes
A1  - Wagner, Torsten
A1  - Keusgen, Michael
A1  - Siegert, Petra
A1  - Schöning, Michael Josef
T1  - Capacitive field‐effect biosensor applied for the detection of acetoin in alcoholic beverages and fermentation broths
JF  - physica status solidi (a) applications and materials science
N2  - 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.
KW  - acetoin
KW  - acetoin reductase
KW  - alcoholic beverages
KW  - biosensors
KW  - capacitive field-effect sensors
Y1  - 2021
U6  - http://dx.doi.org/10.1002/pssa.202000765
SN  - 1862-6319
VL  - 218
IS  - 13
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Muschallik, Lukas
A1  - Molinnus, Denise
A1  - Jablonski, Melanie
A1  - Kipp, Carina Ronja
A1  - Bongaerts, Johannes
A1  - Pohl, Martina
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Selmer, Thorsten
A1  - Siegert, Petra
T1  - Synthesis of α-hydroxy ketones and vicinal (R, R)-diols by Bacillus clausii DSM 8716ᵀ butanediol dehydrogenase
JF  - RSC Advances
N2  - α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716ᵀ (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn²⁺ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated.
Y1  - 2020
U6  - http://dx.doi.org/10.1039/D0RA02066D
SN  - 2046-2069
VL  - 10
SP  - 12206
EP  - 12216
PB  - Royal Society of Chemistry (RSC)
CY  - Cambridge
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  - Muschallik, Lukas
A1  - Molinnus, Denise
A1  - Bongaerts, Johannes
A1  - Pohl, Martina
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Siegert, Petra
A1  - Selmer, Thorsten
T1  - (R,R)-Butane-2,3-diol Dehydrogenase from Bacillus clausii DSM 8716T: Cloning and Expression of the bdhA-Gene, and Initial Characterization of Enzyme
JF  - Journal of Biotechnology
N2  - 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.
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.jbiotec.2017.07.020
SN  - 0168-1656
VL  - 258
SP  - 41
EP  - 50
PB  - Elsevier
CY  - Amsterdam
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  - 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  - 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  - 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  - Takenaga, Shoko
A1  - Biselli, Manfred
A1  - Schnitzler, Thomas
A1  - Öhlschläger, Peter
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
T1  - Toward multi-analyte bioarray sensors: LAPS-based on-chip determination of a Michaelis–Menten-like kinetics for cell culturing
JF  - Physica status solidi A : Applications and materials science
N2  - The metabolic activity of Chinese hamster ovary (CHO) cells was observed using a light-addressable potentiometric sensor (LAPS). The dependency toward different glucose concentrations (17–200 mM) follows a Michaelis–Menten kinetics trajectory with Kₘ = 32.8 mM, and the obtained Kₘ value in this experiment was compared with that found in literature. In addition, the pH shift induced by glucose metabolism of tumor cells transfected with the HPV-16 genome (C3 cells) was successfully observed. These results indicate the possibility to determine the tumor cells metabolism with a LAPS-based measurement device.
Y1  - 2014
U6  - http://dx.doi.org/10.1002/pssa.201330464
SN  - 1521-396X (E); 1862-6319 (E-Journal); 0031-8965 (Print); 1862-6300 (Print)
VL  - 211
IS  - 6
SP  - 1410
EP  - 1415
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Guo, Yuanyuan
A1  - Miyamoto, Ko-ichiro
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Theoretical study and simulation of light-addressable potentiometric sensors
JF  - Physica status solidi (A) : applications and materials
N2  - The light-addressable potentiometric sensor (LAPS) is a semiconductor-based potentiometric sensor using a light probe with an ability of detecting the concentration of biochemical species in a spatially resolved manner. As an important biomedical sensor, research has been conducted to improve its performance, for instance, to realize high-speed measurement. In this work, the idea of facilitating the device-level simulation, instead of using an equivalent-circuit model, is presented for detailed analysis and optimization of the performance of the LAPS. Both carrier distribution and photocurrent response have been simulated to provide new insight into both amplitude-mode and phase-mode operations of the LAPS. Various device parameters can be examined to effectively design and optimize the LAPS structures and setups for enhanced performance.
Y1  - 2014
U6  - http://dx.doi.org/10.1002/pssa.201330354
SN  - 0031-8965
VL  - 211
IS  - 6
SP  - 1467
EP  - 1472
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  - 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  - Werner, Frederik
A1  - Groebel, Simone
A1  - Wagner, Torsten
A1  - Yoshinobu, Tatsuo
A1  - Selmer, Thorsten
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Überwachung der metabolischen Aktivität von Mikroorganismen zur Kontrolle des biologischen Prozesses im Biogasfermenter
JF  - Biogas 2011 : Energieträger der Zukunft ; 6. Fachtagung, Fachtagung Braunschweig, 08. und 09. Juni 2011 / VDI Energie und Umwelt
Y1  - 2011
SN  - 978-3-18-092121-1
N1  - Gesellschaft Energie und Umwelt ; Fachtagung Biogas ; (6 : ; 2011.06.08-09 : ; Braunschweig) ; 	VDI-Berichte ; 2121
SP  - 285
EP  - 286
PB  - VDI-Verl.
CY  - Düsseldorf
ER  - 
TY  - JOUR
A1  - Werner, Frederik
A1  - Groebel, Simone
A1  - Schuhmacher, K.
A1  - Spelthahn, Heiko
A1  - Wagner, Torsten
A1  - Selmer, Thorsten
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Bestimmung der metabolischen Aktivität von Mikroorganismen während des Biogasbildungsprozesses
JF  - 9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]
Y1  - 2009
SN  - 978-3-941298-44-6
N1  - Dresdner Sensor-Symposium ; (9, 2009, Dresden)
SP  - 201
EP  - 204
PB  - TUDpress
CY  - Dresden
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Beging, Stefan
A1  - Rotter, L.
A1  - Poghossian, Arshak
A1  - Biselli, Manfred
A1  - Zang, Werner
A1  - Schöning, Michael Josef
T1  - Online-Messsysteme für die automatisierte Charakterisierung von feldeffektbasierten Biosensoren
JF  - 8. Dresdner Sensor-Symposium : Sensoren für Umwelt, Klima und Sicherheit, Biosensoren und Biosysteme, Sensoren und Sensorsysteme für die Prozesstechnik, Trends in der Sensortechnik, Materialentwicklung für die Sensorik; 8. Dresdner Sensor-Symposium, 10. - 12. Dezember 2007, Dresden / Gerald Gerlach ... (Hg.)
Y1  - 2007
SN  - 978-3-940046-45-1
N1  - Dresdner Sensor-Symposium <8, 2007, Dresden> ; Dresdner Beiträge zur Sensorik ; 29
SP  - 257
EP  - 260
PB  - TUDpress, Verl. der Wissenschaften
CY  - Dresden
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  - Wagner, Torsten
A1  - Molina, R.
A1  - Biselli, Manfred
A1  - Canzoneri, Michele
A1  - Schnitzler, Thomas
A1  - Yoshinobu, Tatsuo
A1  - Schöning, Michael Josef
T1  - A light-addressable potentiometric sensor system for fast, simultaneous and spatial detection of the metabolic activity of biological cells
JF  - 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.)
Y1  - 2007
SN  - 1-4244-0841-5
N1  - Eurosensors 21, 2007, Lyon ; International Conference on Solid-State Sensors, Actuators and Microsystems 14, 2007, Lyon
SP  - 1107
EP  - 1110
PB  - IEEE
CY  - Piscataway
ER  -