@article{TurekHeidenGuoetal.2010, author = {Turek, Monik and Heiden, Wolfgang and Guo, Sharon and Riesen, Alfred and Schubert, J{\"u}rgen and Zander, Willi and Kr{\"u}ger, Peter and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Simultaneous detection of cyanide and heavy metals for environmental analysis by means of µISEs}, series = {Physica Status Solidi (A). 207 (2010), H. 4}, journal = {Physica Status Solidi (A). 207 (2010), H. 4}, isbn = {1862-6300}, pages = {817 -- 823}, year = {2010}, language = {en} } @article{KirchnerLiSpelthahnetal.2011, author = {Kirchner, Patrick and Li, Bin and Spelthahn, Heiko and Henkel, Hartmut and Schneider, Andreas and Friedrich, Peter and Kolstad, Jens and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Thin-film calorimetric H2O2 gas sensor for the validation of germicidal effectivity in aseptic filling processes}, series = {Sensors and Actuators B: Chemical. 154 (2011), H. 2}, journal = {Sensors and Actuators B: Chemical. 154 (2011), H. 2}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {1873-3077}, pages = {257 -- 263}, year = {2011}, language = {en} } @article{WernerWagnerYoshinobuetal.2013, author = {Werner, Frederik and Wagner, Torsten and Yoshinobu, Tatsuo and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Frequency behaviour of light-addressable potentiometric sensors}, series = {Physica Status Solidi (A)}, volume = {210}, journal = {Physica Status Solidi (A)}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-396X ; 0031-8965}, doi = {10.1002/pssa.201200929}, pages = {884 -- 891}, year = {2013}, abstract = {Light-addressable potentiometric sensors (LAPS) are semiconductor-based potentiometric sensors, with the advantage to detect the concentration of a chemical species in a liquid solution above the sensor surface in a spatially resolved manner. The addressing is achieved by a modulated and focused light source illuminating the semiconductor and generating a concentration-depending photocurrent. This work introduces a LAPS set-up that is able to monitor the electrical impedance in addition to the photocurrent. The impedance spectra of a LAPS structure, with and without illumination, as well as the frequency behaviour of the LAPS measurement are investigated. The measurements are supported by electrical equivalent circuits to explain the impedance and the LAPS-frequency behaviour. The work investigates the influence of different parameters on the frequency behaviour of the LAPS. Furthermore, the phase shift of the photocurrent, the influence of the surface potential as well as the changes of the sensor impedance will be discussed.}, language = {en} } @inproceedings{WernerMansourRateikeetal.2011, author = {Werner, Frederik and Mansour, Ahmed and Rateike, Franz-Matthias and Schusser, Sebastian and Wagner, Torsten and Yoshinobu, Tatsuo and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Kompakter Aufbau eines lichtadressierbaren potentiometrischen Sensors mit verfahrbarem Diodenlaser}, series = {10. Dresdner Sensor-Symposium : Dresden, 5. - 7. Dezember 2011 ; miniaturisierte analytische Verfahren, Hochtemperatur-Sensoren, Sensoren f{\"u}r Bioprozess- und Verfahrenstechnik, Sensoren f{\"u}r die Medizin, Chemische Verfahrenstechnik, Lebensmittelanalytik, innovative Sensorl{\"o}sungen, Sensoren f{\"u}r die Wasserqualit{\"a}t, Selbst{\"u}berwachung / Gerald Gerlach ... (Hg.) Dresdner Beitr{\"a}ge zur Sensorik. 43}, booktitle = {10. Dresdner Sensor-Symposium : Dresden, 5. - 7. Dezember 2011 ; miniaturisierte analytische Verfahren, Hochtemperatur-Sensoren, Sensoren f{\"u}r Bioprozess- und Verfahrenstechnik, Sensoren f{\"u}r die Medizin, Chemische Verfahrenstechnik, Lebensmittelanalytik, innovative Sensorl{\"o}sungen, Sensoren f{\"u}r die Wasserqualit{\"a}t, Selbst{\"u}berwachung / Gerald Gerlach ... (Hg.) Dresdner Beitr{\"a}ge zur Sensorik. 43}, editor = {Gerlach, Gerald}, publisher = {TUDpress}, address = {Dresden}, isbn = {978-3-942710-53-4}, pages = {277 -- 280}, year = {2011}, language = {de} } @article{KirchnerReisertPuetzetal.2012, author = {Kirchner, Patrick and Reisert, Steffen and P{\"u}tz, Patrick and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Characterisation of polymeric materials as passivation layer for calorimetric H2O2 gas sensors}, 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.201100773}, pages = {859 -- 863}, year = {2012}, abstract = {Calorimetric gas sensors for monitoring the H₂O₂ concentration at elevated temperatures in industrial sterilisation processes have been presented in previous works. These sensors are built up in form of a differential set-up of a catalytically active and passive temperature-sensitive structure. Although, various types of catalytically active dispersions have been studied, the passivation layer has to be established and therefore, chemically as well as physically characterised. In the present work, fluorinated ethylene propylene (FEP), perfluoralkoxy (PFA) and epoxy-based SU-8 photoresist as temperature-stable polymeric materials have been investigated for sensor passivation in terms of their chemical inertness against H₂O₂, their hygroscopic properties as well as their morphology. The polymeric materials were deposited via spin-coating on the temperature-sensitive structure, wherein spin-coated FEP and PFA show slight agglomerates. However, they possess a low absorption of humidity due to their hydrophobic surface, whereas the SU-8 layer has a closed surface but shows a slightly higher absorption of water. All of them were inert against gaseous H₂O₂ during the characterisation in H₂O₂ atmosphere that demonstrates their suitability as passivation layer for calorimetric H₂O₂ gas sensors.}, language = {en} } @article{TurekSchoeningKloocketal.2008, author = {Turek, Monika and Sch{\"o}ning, Michael Josef and Kloock, Joachim P. and Schubert, J{\"u}rgen and Zander, Willi and Kr{\"u}ger, Peter and Keusgen, Michael}, title = {Herstellung und Charakterisierung eines hybriden Sensorarrays auf Halbleiterbasis f{\"u}r die Umweltanalytik}, series = {Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. M{\"a}rz 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik}, journal = {Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. M{\"a}rz 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092011-5}, pages = {803 -- 810}, year = {2008}, language = {de} } @article{OberlaenderBrommWendeleretal.2015, author = {Oberl{\"a}nder, Jan and Bromm, Alexander and Wendeler, Luisa and Iken, Heiko and Palomar Duran, Marlena and Greeff, Anton and Kirchner, Patrick and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Towards a biosensor to monitor the sterilisation efficiency of aseptic filling machines}, series = {Physica status solidi (a)}, volume = {212}, journal = {Physica status solidi (a)}, number = {6}, publisher = {Wiley}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201431900}, pages = {1299 -- 1305}, year = {2015}, abstract = {Sterilisation processes are compulsory in medicine, pharmacy, and food industries to prevent infections of consumers and microbiological contaminations of products. Monitoring the sterilisation by conventional microbiological methods is time- and lab-consuming. To overcome this problem, in this work a novel biosensor has been proposed. The sensor enables a fast method to evaluate sterilisation processes. By means of thin-film technology the sensor's transducer structures in form of IDEs (interdigitated electrodes) have been fabricated on a silicon substrate. Physical characterisation of the developed sensor was done by AFM, SEM, and profilometry. Impedance analyses were conducted for the electrical characterisation. As microbiological layer spores of B. atrophaeus have been immobilised on the sensing structure; spores of this type are a well-known sterilisation test organism. Impedance measurements at a fixed frequency over time were performed to monitor the immobilisation process. A sterilisation process according to aseptic filling machines was applied to demonstrate the sensor functionality. After both, immobilisation and sterilisation, a change in impedance could successfully be detected.}, language = {en} } @article{PilasIkenSelmeretal.2015, author = {Pilas, Johanna and Iken, Heiko and Selmer, Thorsten and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Development of a multi-parameter sensor chip for the simultaneous detection of organic compounds in biogas processes}, series = {Physica status solidi (a)}, volume = {212}, journal = {Physica status solidi (a)}, number = {6}, publisher = {Wiley}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201431894}, pages = {1306 -- 1312}, year = {2015}, abstract = {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.}, language = {en} } @article{OberlaenderJildehKirchneretal.2015, author = {Oberl{\"a}nder, Jan and Jildeh, Zaid B. and Kirchner, Patrick and Wendeler, Luisa and Bromm, Alexander and Iken, Heiko and Wagner, Patrick and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Study of Interdigitated Electrode Arrays Using Experiments and Finite Element Models for the Evaluation of Sterilization Processes}, series = {Sensors}, volume = {15}, journal = {Sensors}, number = {10}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s151026115}, pages = {26115 -- 26127}, year = {2015}, abstract = {In this work, a sensor to evaluate sterilization processes with hydrogen peroxide vapor has been characterized. Experimental, analytical and numerical methods were applied to evaluate and study the sensor behavior. The sensor set-up is based on planar interdigitated electrodes. The interdigitated electrode structure consists of 614 electrode fingers spanning over a total sensing area of 20 mm2. Sensor measurements were conducted with and without microbiological spores as well as after an industrial sterilization protocol. The measurements were verified using an analytical expression based on a first-order elliptical integral. A model based on the finite element method with periodic boundary conditions in two dimensions was developed and utilized to validate the experimental findings.}, language = {en} } @article{ArreolaMaetzkowDuranetal.2016, author = {Arreola, Julio and M{\"a}tzkow, Malte and Dur{\´a}n, Marlena Palomar and Greeff, Anton and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Optimization of the immobilization of bacterial spores on glass substrates with organosilanes}, series = {Physica status solidi (A) : Applications and materials science}, volume = {213}, journal = {Physica status solidi (A) : Applications and materials science}, number = {6}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201532914}, pages = {1463 -- 1470}, year = {2016}, abstract = {Spores can be immobilized on biosensors to function as sensitive recognition elements. However, the immobilization can affect the sensitivity and reproducibility of the sensor signal. In this work, three different immobilization strategies with organosilanes were optimized and characterized to immobilize Bacillus atrophaeus spores on glass substrates. Five different silanization parameters were investigated: nature of the solvent, concentration of the silane, silanization time, curing process, and silanization temperature. The resulting silane layers were resistant to a buffer solution (e.g., Ringer solution) with a polysorbate (e.g., Tween®80) and sonication.}, language = {en} } @article{OberlaenderKirchnerKeusgenetal.2015, author = {Oberl{\"a}nder, Jan and Kirchner, Patrick and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Strategies in developing thin-film sensors for monitoring aseptic food processes : Theoretical considerations and investigations of passivation materials}, series = {Electrochimica Acta}, volume = {183}, journal = {Electrochimica Acta}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0013-4686}, doi = {10.1016/j.electacta.2015.06.126}, pages = {130 -- 136}, year = {2015}, abstract = {The sterilization of packages in aseptic food processes is highly significant to maintain a consumer-safe product with extended shelf-life. Today, the sterilization of food packages is predominantly accomplished by gaseous hydrogen peroxide (H2O2) in combination with heat. In order to monitor this sterilization process, calorimetric gas sensors as differential set-up of two platinum temperature sensors representing a catalytically active (additionally deposition of MnO2) and a passive segment have been recently developed. The temperature rise of the exothermic decomposition serves as an indicator of the present H2O2 concentration. In the present work, a theoretical approach considering the sensor's thermochemistry and physical transport phenomena was formulated to evaluate the temperature rise based on the energy content of gaseous H2O2. In a further part of this work, three polymers have been analyzed with respect to their application as passivation materials. The examined polymers are photoresist SU-8, perfluoroalkoxy (PFA) and fluorinated ethylene propylene (FEP). Thermal analyses by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) have been conducted to determine the operation limits of the polymers. The overall chemical resistance and stability of the polymers against the harsh environmental conditions during the sterilization process have been examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR).}, language = {en} } @inproceedings{OberlaenderJildehKirchneretal.2015, author = {Oberl{\"a}nder, Jan and Jildeh, Zaid B. and Kirchner, Patrick and Wendeler, Luisa and Bromm, Alexander and Iken, Heiko and Wagner, Patrick and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Experimental and numerical evaluation of interdigitated electrode array for monitoring gaseous sterilization processes}, series = {12. Dresdner Sensor-Symposium 2015}, booktitle = {12. Dresdner Sensor-Symposium 2015}, doi = {10.5162/12dss2015/P3.11}, pages = {163 -- 168}, year = {2015}, 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{WagnerVornholtWerneretal.2016, author = {Wagner, Torsten and Vornholt, Wolfgang and Werner, Frederik and Yoshinobu, Tatsuo and Miyamoto, Ko-Ichiro and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Light-addressable potentiometric sensor (LAPS) combined with magnetic beads for pharmaceutical screening}, series = {Physics in medicine}, volume = {2016}, journal = {Physics in medicine}, number = {1}, issn = {2352-4510}, doi = {10.1016/j.phmed.2016.03.001}, pages = {2 -- 7}, year = {2016}, abstract = {The light-addressable potentiometric sensor (LAPS) has the unique feature to address different regions of a sensor surface without the need of complex structures. Measurements at different locations on the sensor surface can be performed in a common analyte solution, which distinctly simplifies the fluidic set-up. However, the measurement in a single analyte chamber prevents the application of different drugs or different concentrations of a drug to each measurement spot at the same time as in the case of multi-reservoir-based set-ups. In this work, the authors designed a LAPS-based set-up for cell culture screening that utilises magnetic beads loaded with the endotoxin (lipopolysaccharides, LPS), to generate a spatially distributed gradient of analyte concentration. Different external magnetic fields can be adjusted to move the magnetic beads loaded with a specific drug within the measurement cell. By recording the metabolic activities of a cell layer cultured on top of the LAPS surface, this work shows the possibility to apply different concentrations of a sample along the LAPS measurement spots within a common analyte solution.}, language = {en} } @article{CornelisGivanoudiYongabietal.2019, author = {Cornelis, Peter and Givanoudi, Stella and Yongabi, Derick and Iken, Heiko and Duw{\´e}, Sam and Deschaume, Olivier and Robbens, Johan and Dedecker, Peter and Bartic, Carmen and W{\"u}bbenhorst, Michael and Sch{\"o}ning, Michael Josef and Heyndrickx, Marc and Wagner, Patrick}, title = {Sensitive and specific detection of E. coli using biomimetic receptors in combination with a modified heat-transfer method}, series = {Biosensors and Bioelectronics}, volume = {136}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0956-5663}, doi = {10.1016/j.bios.2019.04.026}, pages = {97 -- 105}, year = {2019}, language = {en} } @article{ArreolaOberlaenderMaetzkowetal.2017, author = {Arreola, Julio and Oberl{\"a}nder, Jan and M{\"a}tzkow, M. and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Surface functionalization for spore-based biosensors with organosilanes}, series = {Electrochimica Acta}, volume = {241}, journal = {Electrochimica Acta}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0013-4686}, doi = {10.1016/j.electacta.2017.04.157}, pages = {237 -- 243}, year = {2017}, abstract = {In the present work, surface functionalization of different sensor materials was studied. Organosilanes are well known to serve as coupling agent for biomolecules or cells on inorganic materials. 3-aminopropyltriethoxysilane (APTES) was used to attach microbiological spores time to an interdigitated sensor surface. The functionality and physical properties of APTES were studied on isolated sensor materials, namely silicon dioxide (SiO2) and platinum (Pt) as well as the combined material on sensor level. A predominant immobilization of spores could be demonstrated on SiO2 surfaces. Additionally, the impedance signal of APTES-functionalized biosensor chips has been investigated.}, language = {en} } @article{OberlaenderMayerGreeffetal.2018, author = {Oberl{\"a}nder, Jan and Mayer, Marlena and Greeff, Anton and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Spore-based biosensor to monitor the microbicidal efficacy of gaseous hydrogen peroxide sterilization processes}, series = {Biosensors and Bioelectronics}, volume = {104}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0956-5663}, doi = {10.1016/j.bios.2017.12.045}, pages = {87 -- 94}, year = {2018}, abstract = {In this work, a spore-based biosensor is evaluated to monitor the microbicidal efficacy of sterilization processes applying gaseous hydrogen peroxide (H2O2). The sensor is based on interdigitated electrode structures (IDEs) that have been fabricated by means of thin-film technologies. Impedimetric measurements are applied to study the effect of sterilization process on spores of Bacillus atrophaeus. This resilient microorganism is commonly used in industry to proof the sterilization efficiency. The sensor measurements are accompanied by conventional microbiological challenge tests, as well as morphological characterizations with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensor measurements are correlated with the microbiological test routines. In both methods, namely the sensor-based and microbiological one, a tailing effect has been observed. The results are evaluated and discussed in a three-dimensional calibration plot demonstrating the sensor's suitability to enable a rapid process decision in terms of a successfully performed sterilization.}, language = {en} } @article{ArreolaKeusgenSchoening2019, author = {Arreola, Julio and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Toward an immobilization method for spore-based biosensors in oxidative environment}, series = {Electrochimica Acta}, volume = {302}, journal = {Electrochimica Acta}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.electacta.2019.01.148}, pages = {394 -- 401}, year = {2019}, language = {en} } @article{ArreolaKeusgenWagneretal.2019, author = {Arreola, Julio and Keusgen, Michael and Wagner, Torsten and Sch{\"o}ning, Michael Josef}, title = {Combined calorimetric gas- and spore-based biosensor array for online monitoring and sterility assurance of gaseous hydrogen peroxide in aseptic filling machines}, series = {Biosensors and Bioelectronics}, volume = {143}, journal = {Biosensors and Bioelectronics}, number = {111628}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0956-5663}, doi = {10.1016/j.bios.2019.111628}, year = {2019}, language = {en} } @article{PilasSelmerKeusgenetal.2019, author = {Pilas, Johanna and Selmer, Thorsten and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Screen-printed carbon electrodes modified with graphene oxide for the design of a reagent-free NAD+-dependent biosensor array}, series = {Analytical Chemistry}, volume = {91}, journal = {Analytical Chemistry}, number = {23}, publisher = {ACS Publications}, address = {Washington}, doi = {10.1021/acs.analchem.9b04481}, pages = {15293 -- 15299}, year = {2019}, language = {en} }