@article{BaeckerRakowskiKrappenetal.2017,
  author    = {B{\"a}cker, M. and Rakowski, D. and Krappen, E. and Sch{\"o}ning, Michael Josef},
  title     = {Reinigungsprozesse in der Lebensmittelindustrie. Entwicklung eines Demonstrators zur {\"U}berwachung},
  series = {GIT Labor-Fachzeitschrift},
  volume    = {61},
  journal   = {GIT Labor-Fachzeitschrift},
  number    = {8},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0016-3538},
  pages     = {26 -- 28},
  year      = {2017},
  language  = {de}
}
@article{AboulnagaZouSelmeretal.2018,
  author    = {Aboulnaga, E. A. and Zou, H. and Selmer, Thorsten and Xian, M.},
  title     = {Development of a plasmid-based, tunable, tolC-derived expression system for application in Cupriavidus necator H16},
  series = {Journal of Biotechnology},
  volume    = {274},
  journal   = {Journal of Biotechnology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-1656},
  doi       = {10.1016/j.jbiotec.2018.03.007},
  pages     = {15 -- 27},
  year      = {2018},
  abstract  = {Cupriavidus necator H16 gains increasing attention in microbial research and biotechnological application due to its diverse metabolic features. Here we present a tightly controlled gene expression system for C. necator including the pBBR1-vector that contains hybrid promoters originating from C. necator native tolC-promoter in combination with a synthetic tetO-operator. The expression of the reporter gene from these plasmids relies on the addition of the exogenous inducer doxycycline (dc). The novel expression system offers a combination of advantageous features as; (i) high and dose-dependent recombinant protein production, (ii) tight control with a high dynamic range (On/Off ratio), which makes it applicable for harmful pathways or for toxic protein production, (iii) comparable cheap inducer (doxycycline, dc), (iv) effective at low inducer concentration, that makes it useful for large scale application, (v) rapid, diffusion controlled induction, and (vi) the inducer does not interfere within the cell metabolism. As applications of the expression system in C. necator H16, the growth ability on glycerol was enhanced by constitutively expressing the E. coli glpk gene-encoding for glycerol kinase. Likewise, we used the system to overcome the expression toxicity of mevalonate pathway in C. necator H16. With this system, the mevalonate-genes were successfully introduced in the host and the recombinant strains could produce about 200 mg/l mevalonate.},
  language  = {en}
}
@article{KochPoghossianSchoeningetal.2018,
  author    = {Koch, Claudia and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Wege, Christian},
  title     = {Penicillin Detection by Tobacco Mosaic Virus-Assisted Colorimetric Biosensors},
  series = {Nanotheranostics},
  volume    = {2},
  journal   = {Nanotheranostics},
  number    = {2},
  publisher = {Ivyspring},
  address   = {Sydney},
  issn      = {2206-7418},
  doi       = {10.7150/ntno.22114},
  pages     = {184 -- 196},
  year      = {2018},
  abstract  = {The presentation of enzymes on viral scaffolds has beneficial effects such as an increased enzyme loading and a prolonged reusability in comparison to conventional immobilization platforms. Here, we used modified tobacco mosaic virus (TMV) nanorods as enzyme carriers in penicillin G detection for the first time. Penicillinase enzymes were conjugated with streptavidin and coupled to TMV rods by use of a bifunctional biotin-linker. Penicillinase-decorated TMV particles were characterized extensively in halochromic dye-based biosensing. Acidometric analyte detection was performed with bromcresol purple as pH indicator and spectrophotometry. The TMV-assisted sensors exhibited increased enzyme loading and strongly improved reusability, and higher analysis rates compared to layouts without viral adapters. They extended the half-life of the sensors from 4 - 6 days to 5 weeks and thus allowed an at least 8-fold longer use of the sensors. Using a commercial budget-priced penicillinase preparation, a detection limit of 100 µM penicillin was obtained. Initial experiments also indicate that the system may be transferred to label-free detection layouts.},
  language  = {en}
}
@article{VahidpourOberlaenderSchoening2018,
  author    = {Vahidpour, Farnoosh and Oberl{\"a}nder, Jan and Sch{\"o}ning, Michael Josef},
  title     = {Flexible Calorimetric Gas Sensors for Detection of a Broad Concentration Range of Gaseous Hydrogen Peroxide: A Step Forward to Online Monitoring of Food-Package Sterilization Processes},
  series = {Phys. Status Solidi A},
  volume    = {215},
  journal   = {Phys. Status Solidi A},
  number    = {15},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  doi       = {10.1002/pssa.201800044},
  pages     = {Artikel 1800044},
  year      = {2018},
  abstract  = {In this study, flexible calorimetric gas sensors are developed for specificdetection of gaseous hydrogen peroxide (H₂O₂) over a wide concentrationrange, which is used in sterilization processes for aseptic packaging industry.The flexibility of these sensors is an advantage for identifying the chemical components of the sterilant on the corners of the food boxes, so-called "coldspots", as critical locations in aseptic packaging, which are of great importance. These sensors are fabricated on flexible polyimide films by means of thin-film technique. Thin layers of titanium and platinum have been deposited on polyimide to define the conductive structures of the sensors. To detect the high-temperature evaporated H₂O₂, a differential temperature set-up is proposed. The sensors are evaluated in a laboratory-scaled sterilizationsystem to simulate the sterilization process. The concentration range of the evaporated H₂O₂ from 0 to 7.7\% v/v was defined and the sensors have successfully detected high as well as low H₂O₂ concentrations with a sensitivity of 5.04 °C/\% v/v. The characterizations of the sensors confirm their precise fabrication, high sensitivity and the novelty of low H₂O₂ concentration detections for future inline monitoring of food-package sterilization.},
  language  = {en}
}
@article{PoghossianJablonskiKochetal.2018,
  author    = {Poghossian, Arshak and Jablonski, Melanie and Koch, Claudia and Bronder, Thomas and Rolka, David and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {Field-effect biosensor using virus particles as scaffolds for enzyme immobilization},
  series = {Biosensors and Bioelectronics},
  volume    = {110},
  journal   = {Biosensors and Bioelectronics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0956-5663},
  doi       = {10.1016/j.bios.2018.03.036},
  pages     = {168 -- 174},
  year      = {2018},
  abstract  = {A field-effect biosensor employing tobacco mosaic virus (TMV) particles as scaffolds for enzyme immobilization is presented. Nanotubular TMV scaffolds allow a dense immobilization of precisely positioned enzymes with retained activity. To demonstrate feasibility of this new strategy, a penicillin sensor has been developed by coupling a penicillinase with virus particles as a model system. The developed field-effect penicillin biosensor consists of an Al-p-Si-SiO₂-Ta₂O₅-TMV structure and has been electrochemically characterized in buffer solutions containing different concentrations of penicillin G. In addition, the morphology of the biosensor surface with virus particles was characterized by scanning electron microscopy and atomic force microscopy methods. The sensors possessed a high penicillin sensitivity of ~ 92 mV/dec in a nearly-linear range from 0.1 mM to 10 mM, and a low detection limit of about 50 µM. The long-term stability of the penicillin biosensor was periodically tested over a time period of about one year without any significant loss of sensitivity. The biosensor has also been successfully applied for penicillin detection in bovine milk samples.},
  language  = {en}
}
@article{MiyamotoSekiSutoetal.2018,
  author    = {Miyamoto, Koichiro and Seki, Kosuke and Suto, Takeyuki and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers},
  series = {Sensor and Actuators B: Chemical},
  volume    = {273},
  journal   = {Sensor and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2018.07.016},
  pages     = {1328 -- 1333},
  year      = {2018},
  abstract  = {The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.},
  language  = {en}
}
@article{RoehlenPilasDahmenetal.2018,
  author    = {R{\"o}hlen, Desiree and Pilas, Johanna and Dahmen, Markus and Keusgen, Michael and Selmer, Thorsten and Sch{\"o}ning, Michael Josef},
  title     = {Toward a Hybrid Biosensor System for Analysis of Organic and Volatile Fatty Acids in Fermentation Processes},
  series = {Frontiers in Chemistry},
  journal   = {Frontiers in Chemistry},
  number    = {6},
  publisher = {Frontiers},
  address   = {Lausanne},
  doi       = {10.3389/fchem.2018.00284},
  pages     = {Artikel 284},
  year      = {2018},
  abstract  = {Monitoring of organic acids (OA) and volatile fatty acids (VFA) is crucial for the control of anaerobic digestion. In case of unstable process conditions, an accumulation of these intermediates occurs. In the present work, two different enzyme-based biosensor arrays are combined and presented for facile electrochemical determination of several process-relevant analytes. Each biosensor utilizes a platinum sensor chip (14 × 14 mm²) with five individual working electrodes. The OA biosensor enables simultaneous measurement of ethanol, formate, d- and l-lactate, based on a bi-enzymatic detection principle. The second VFA biosensor provides an amperometric platform for quantification of acetate and propionate, mediated by oxidation of hydrogen peroxide. The cross-sensitivity of both biosensors toward potential interferents, typically present in fermentation samples, was investigated. The potential for practical application in complex media was successfully demonstrated in spiked sludge samples collected from three different biogas plants. Thereby, the results obtained by both of the biosensors were in good agreement to the applied reference measurements by photometry and gas chromatography, respectively. The proposed hybrid biosensor system was also used for long-term monitoring of a lab-scale biogas reactor (0.01 m³) for a period of 2 months. In combination with typically monitored parameters, such as gas quality, pH and FOS/TAC (volatile organic acids/total anorganic carbonate), the amperometric measurements of OA and VFA concentration could enhance the understanding of ongoing fermentation processes.},
  language  = {en}
}
@article{RodriguesMoraisNordietal.2018,
  author    = {Rodrigues, Raul T. and Morais, Paulo V. and Nordi, Cristina S. F. and Sch{\"o}ning, Michael Josef and Siqueira Jr., Jos{\´e} R. and Caseli, Luciano},
  title     = {Carbon Nanotubes and Algal Polysaccharides To Enhance the Enzymatic Properties of Urease in Lipid Langmuir-Blodgett Films},
  series = {Langmuir},
  volume    = {34},
  journal   = {Langmuir},
  number    = {9},
  publisher = {ACS Publications},
  address   = {Washington, DC},
  issn      = {1520-5827},
  doi       = {10.1021/acs.langmuir.7b04317},
  pages     = {3082 -- 3093},
  year      = {2018},
  abstract  = {Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air-water interface were investigated by surface pressure-area isotherms, surface potential-area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte-insulator-semiconductor (EIS) devices, through the Langmuir-Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV-vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance-voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications.},
  language  = {en}
}
@book{SchoeningPoghossian2018,
  author    = {Sch{\"o}ning, Michael Josef and Poghossian, Arshak},
  title     = {Label-free biosensing: advanced materials, devices and applications},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-75219-8},
  pages     = {xii, 480 Seiten ; Illustrationen, Diagramme},
  year      = {2018},
  language  = {en}
}
@incollection{YoshinobuKrauseMiyamotoetal.2018,
  author    = {Yoshinobu, Tatsuo and Krause, Steffi and Miyamoto, Ko-ichiro and Werner, Frederik and Poghossian, Arshak and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {(Bio-)chemical Sensing and Imaging by LAPS and SPIM},
  series = {Label-free biosensing: advanced materials, devices and applications},
  booktitle = {Label-free biosensing: advanced materials, devices and applications},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-75219-8},
  pages     = {103 -- 132},
  year      = {2018},
  abstract  = {The light-addressable potentiometric sensor (LAPS) and scanning photo-induced impedance microscopy (SPIM) are two closely related methods to visualise the distributions of chemical species and impedance, respectively, at the interface between the sensing surface and the sample solution. They both have the same field-effect structure based on a semiconductor, which allows spatially resolved and label-free measurement of chemical species and impedance in the form of a photocurrent signal generated by a scanning light beam. In this article, the principles and various operation modes of LAPS and SPIM, functionalisation of the sensing surface for measuring various species, LAPS-based chemical imaging and high-resolution sensors based on silicon-on-sapphire substrates are described and discussed, focusing on their technical details and prospective applications.},
  language  = {en}
}
@incollection{SchoeningPoghossian2018,
  author    = {Sch{\"o}ning, Michael Josef and Poghossian, Arshak},
  title     = {Enzyme und Biosensorik},
  series = {Einf{\"u}hrung in die Enzymtechnologie},
  booktitle = {Einf{\"u}hrung in die Enzymtechnologie},
  publisher = {Springer Spektrum},
  address   = {Berlin},
  isbn      = {978-3-662-57619-9},
  doi       = {10.1007/978-3-662-57619-9_18},
  pages     = {323 -- 347},
  year      = {2018},
  abstract  = {Enzymbasierte Biosensoren finden seit mehr als f{\"u}nf Jahrzehnten einen prosperierenden Wachstumsmarkt und werden zunehmend auch in biotechnologischen Prozessen eingesetzt. In diesem Kapitel werden, ausgehend vom Sensorbegriff und typischen Kenngr{\"o}ßen f{\"u}r Biosensoren (Abschn. 18.1), elektrochemische Enzym-Biosensoren vorgestellt und deren typischen Einsatzgebiete diskutiert (Abschn. 18.2). Ein Blick {\"u}ber den „Tellerrand" hinaus zeigt alternative Transduktorprinzipien (Abschn. 18.3) und f{\"u}hrt abschließend in aktuelle Forschungstrends ein (Abschn. 18.4).},
  language  = {de}
}
@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{BronderPoghossianJessingetal.2019,
  author    = {Bronder, Thomas and Poghossian, Arshak and Jessing, Max P. and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Surface regeneration and reusability of label-free DNA biosensors based on weak polyelectrolyte-modified capacitive field-effect structures},
  series = {Biosensors and Bioelectronics},
  volume    = {126},
  journal   = {Biosensors and Bioelectronics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0956-5663},
  doi       = {10.1016/j.bios.2018.11.019},
  pages     = {510 -- 517},
  year      = {2019},
  language  = {en}
}
@book{Molinnus2018,
  author    = {Molinnus, Denise},
  title     = {Integration of biomolecular logic principles with electronic transducers on a chip},
  publisher = {Philipps-Universit{\"a}t / Fachbereich Pharmazie},
  address   = {Marburg/Lahn},
  year      = {2018},
  language  = {de}
}
@article{MoraisSilvaDantasetal.2019,
  author    = {Morais, Paulo V. and Silva, Anielle C. A. and Dantas, Noelio O. and Sch{\"o}ning, Michael Josef and Siqueira, Jos{\´e} R., Jr.},
  title     = {Hybrid Layer-by-Layer Film of Polyelectrolytes-Embedded Catalytic CoFe2O4 Nanocrystals as Sensing Units in Capacitive Electrolyte-Insulator-Semiconductor Devices},
  series = {physica status solidi a : applications and materials sciences},
  volume    = {216},
  journal   = {physica status solidi a : applications and materials sciences},
  number    = {1900044},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/pssa.201900044},
  pages     = {1 -- 9},
  year      = {2019},
  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{PoghossianGeisslerSchoening2019,
  author    = {Poghossian, Arshak and Geissler, Hanno and Sch{\"o}ning, Michael Josef},
  title     = {Rapid methods and sensors for milk quality monitoring and spoilage detection},
  series = {Biosensors and Bioelectronics},
  volume    = {140},
  journal   = {Biosensors and Bioelectronics},
  number    = {Article 111272},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0956-5663},
  doi       = {10.1016/j.bios.2019.04.040},
  year      = {2019},
  language  = {en}
}
@article{SchiffelsSelmer2019,
  author    = {Schiffels, Johannes and Selmer, Thorsten},
  title     = {Combinatorial assembly of ferredoxin-linked modules in Escherichia coli yields a testing platform for Rnf-complexes},
  series = {Biotechnology and Bioengineering},
  journal   = {Biotechnology and Bioengineering},
  number    = {accepted article},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/bit.27079},
  pages     = {1 -- 36},
  year      = {2019},
  language  = {en}
}
@article{BreuerPilasGuthmannetal.2019,
  author    = {Breuer, Lars and Pilas, Johanna and Guthmann, Eric and Sch{\"o}ning, Michael Josef and Thoelen, Ronald and Wagner, Torsten},
  title     = {Towards light-addressable flow control: responsive hydrogels with incorporated graphene oxide as laser-driven actuator structures within microfluidic channels},
  series = {Sensor and Actuators B: Chemical},
  volume    = {288},
  journal   = {Sensor and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2019.02.086},
  pages     = {579 -- 585},
  year      = {2019},
  language  = {en}
}
@incollection{SchoeningWagnerPoghossianetal.2018,
  author    = {Sch{\"o}ning, Michael Josef and Wagner, Torsten and Poghossian, Arshak and Miyamoto, K.I. and Werner, C.F. and Krause, S. and Yoshinobu, T.},
  title     = {Light-addressable potentiometric sensors for (bio-)chemical sensing and imaging},
  series = {Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry. Vol. 7},
  booktitle = {Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry. Vol. 7},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {9780128097397},
  pages     = {295 -- 308},
  year      = {2018},
  language  = {en}
}
@article{DantismRoehlenWagneretal.2019,
  author    = {Dantism, Shahriar and R{\"o}hlen, Desiree and Wagner, Torsten and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {A LAPS-based differential sensor for parallelized metabolism monitoring of various bacteria},
  series = {Sensors},
  volume    = {19},
  journal   = {Sensors},
  number    = {21},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s19214692},
  pages     = {Artikel 4692},
  year      = {2019},
  abstract  = {Monitoring the cellular metabolism of bacteria in (bio)fermentation processes is crucial to control and steer them, and to prevent undesired disturbances linked to metabolically inactive microorganisms. In this context, cell-based biosensors can play an important role to improve the quality and increase the yield of such processes. This work describes the simultaneous analysis of the metabolic behavior of three different types of bacteria by means of a differential light-addressable potentiometric sensor (LAPS) set-up. The study includes Lactobacillus brevis, Corynebacterium glutamicum, and Escherichia coli, which are often applied in fermentation processes in bioreactors. Differential measurements were carried out to compensate undesirable influences such as sensor signal drift, and pH value variation during the measurements. Furthermore, calibration curves of the cellular metabolism were established as a function of the glucose concentration or cell number variation with all three model microorganisms. In this context, simultaneous (bio)sensing with the multi-organism LAPS-based set-up can open new possibilities for a cost-effective, rapid detection of the extracellular acidification of bacteria on a single sensor chip. It can be applied to evaluate the metabolic response of bacteria populations in a (bio)fermentation process, for instance, in the biogas fermentation process.},
  language  = {en}
}
@article{KarschuckFilipovBollellaetal.2019,
  author    = {Karschuck, T. L. and Filipov, Y. and Bollella, P. and Sch{\"o}ning, Michael Josef and Katz, E.},
  title     = {Not-XOR (NXOR) logic gate based on an enzyme-catalyzed reaction},
  series = {International Journal of Unconventional Computing},
  volume    = {14},
  journal   = {International Journal of Unconventional Computing},
  number    = {3-4},
  publisher = {Old City Publishing},
  address   = {Philadelphia},
  issn      = {1548-7199},
  pages     = {235 -- 242},
  year      = {2019},
  abstract  = {Enzyme-catalyzed reactions have been designed to mimic various Boolean logic gates in the general framework of unconventional biomolecular computing. While some of the logic gates, particularly OR, AND, are easy to realize with biocatalytic reactions and have been reported in numerous publications, some other, like NXOR, are very challenging and have not been realized yet with enzyme reactions. The paper reports on a novel approach to mimicking the NXOR logic gate using the bell-shaped enzyme activity dependent on pH values. Shifting pH from the optimum value to the acidic or basic values by using acid or base inputs (meaning 1,0 and 0,1 inputs) inhibits the enzyme reaction, while keeping the optimum pH (assuming 0,0 and 1,1 input combinations) preserves a high enzyme activity. The challenging part of the present approach is the selection of an enzyme with a well-demonstrated bell-shape activity dependence on the pH value. While many enzymes can satisfy this condition, we selected pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase as this enzyme has the optimum pH center-located on the pH scale allowing the enzyme activity change by the acidic and basic pH shift from the optimum value corresponding to the highest activity. The present NXOR gate is added to the biomolecular "toolbox" as a new example of Boolean logic gates based on enzyme reactions.},
  language  = {en}
}
@article{MennickenPeterKaulenetal.2019,
  author    = {Mennicken, Max and Peter, Sophia Katharina and Kaulen, Corinna and Simon, Ulrich and Karth{\"a}user, Silvia},
  title     = {Controlling the Electronic Contact at the Terpyridine/Metal Interface},
  series = {The Journal of Physical Chemistry C},
  volume    = {123},
  journal   = {The Journal of Physical Chemistry C},
  number    = {35},
  issn      = {1932-7455},
  doi       = {10.1021/acs.jpcc.9b05865},
  pages     = {21367 -- 21375},
  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{JildehKirchnerBaltesetal.2019,
  author    = {Jildeh, Zaid B. and Kirchner, Patrick and Baltes, Klaus and Wagner, Patrick H. and Sch{\"o}ning, Michael Josef},
  title     = {Development of an in-line evaporation unit for the production of gas mixtures containing hydrogen peroxide - numerical modeling and experimental results},
  series = {International Journal of Heat and Mass Transfer},
  volume    = {143},
  journal   = {International Journal of Heat and Mass Transfer},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0017-9310},
  doi       = {10.1016/j.ijheatmasstransfer.2019.118519},
  pages     = {Article number 118519},
  year      = {2019},
  abstract  = {Hydrogen peroxide (H2O2) is a typical surface sterilization agent for packaging materials used in the pharmaceutical, food and beverage industries. We use the finite-elements method to analyze the conceptual design of an in-line thermal evaporation unit to produce a heated gas mixture of air and evaporated H2O2 solution. For the numerical model, the required phase-transition variables of pure H2O2 solution and of the aerosol mixture are acquired from vapor-liquid equilibrium (VLE) diagrams derived from vapor-pressure formulations. This work combines homogeneous single-phase turbulent flow with heat-transfer physics to describe the operation of the evaporation unit. We introduce the apparent heat-capacity concept to approximate the non-isothermal phase-transition process of the H2O2-containing aerosol. Empirical and analytical functions are defined to represent the temperature- and pressure-dependent material properties of the aqueous H2O2 solution, the aerosol and the gas mixture. To validate the numerical model, the simulation results are compared to experimental data on the heating power required to produce the gas mixture. This shows good agreement with the deviations below 10\%. Experimental observations on the formation of deposits due to the evaporation of stabilized H2O2 solution fits the prediction made from simulation results.},
  language  = {en}
}
@misc{BergerBiselliDinteretal.2000,
  author    = {Berger, Eric G. and Biselli, Manfred and Dinter, Andr{\´e} and Eisenkr{\"a}tzer, Detlef and Kiesewetter, Andr{\´e} and Zeng, Steffen},
  title     = {Chinese-Hamster-Ovary-Zellen zur Produktion von Proteinen},
  pages     = {1 -- 6},
  year      = {2000},
  language  = {de}
}
@article{OezsoyluKizildagSchoeningetal.2020,
  author    = {{\"O}zsoylu, Dua and Kizildag, Sefa and Sch{\"o}ning, Michael Josef and Wagner, Torsten},
  title     = {Differential chemical imaging of extracellular acidification within microfluidic channels using a plasma-functionalized light-addressable potentiometric sensor (LAPS)},
  series = {Physics in Medicine},
  volume    = {10},
  journal   = {Physics in Medicine},
  number    = {100030},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2352-4510},
  doi       = {10.1016/j.phmed.2020.100030},
  pages     = {8},
  year      = {2020},
  abstract  = {Extracellular acidification is a basic indicator for alterations in two vital metabolic pathways: glycolysis and cellular respiration. Measuring these alterations by monitoring extracellular acidification using cell-based biosensors such as LAPS plays an important role in studying these pathways whose disorders are associated with numerous diseases including cancer. However, the surface of the biosensors must be specially tailored to ensure high cell compatibility so that cells can represent more in vivo-like behavior, which is critical to gain more realistic in vitro results from the analyses, e.g., drug discovery experiments. In this work, O2 plasma patterning on the LAPS surface is studied to enhance surface features of the sensor chip, e.g., wettability and biofunctionality. The surface treated with O2 plasma for 30 s exhibits enhanced cytocompatibility for adherent CHO-K1 cells, which promotes cell spreading and proliferation. The plasma-modified LAPS chip is then integrated into a microfluidic system, which provides two identical channels to facilitate differential measurements of the extracellular acidification of CHO-K1 cells. To the best of our knowledge, it is the first time that extracellular acidification within microfluidic channels is quantitatively visualized as differential (bio-)chemical images.},
  language  = {en}
}
@article{MuschallikKippReckeretal.2020,
  author    = {Muschallik, Lukas and Kipp, Carina Ronja and Recker, Inga and Bongaerts, Johannes and Pohl, Martina and Gelissen, Melanie and Sch{\"o}ning, Michael Josef and Selmer, Thorsten and Siegert, Petra},
  title     = {Synthesis of α-hydroxy ketones and vicinal diols with the Bacillus licheniformis DSM 13T butane-2, 3-diol dehydrogenase},
  series = {Journal of Biotechnology},
  volume    = {202},
  journal   = {Journal of Biotechnology},
  number    = {Vol. 324},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {2590-1559},
  doi       = {10.1016/j.jbiotec.2020.09.016},
  pages     = {61 -- 70},
  year      = {2020},
  abstract  = {The enantioselective synthesis of α-hydroxy ketones and vicinal diols is an intriguing field because of the broad applicability of these molecules. Although, butandiol dehydrogenases are known to play a key role in the production of 2,3-butandiol, their potential as biocatalysts is still not well studied. Here, we investigate the biocatalytic properties of the meso-butanediol dehydrogenase from Bacillus licheniformis DSM 13T (BlBDH). The encoding gene was cloned with an N-terminal StrepII-tag and recombinantly overexpressed in E. coli. BlBDH is highly active towards several non-physiological diketones and α-hydroxyketones with varying aliphatic chain lengths or even containing phenyl moieties. By adjusting the reaction parameters in biotransformations the formation of either the α-hydroxyketone intermediate or the diol can be controlled.},
  language  = {en}
}
@article{FalkenbergRahbaFischeretal.2022,
  author    = {Falkenberg, Fabian and Rahba, Jade and Fischer, David and Bott, Michael and Bongaerts, Johannes and Siegert, Petra},
  title     = {Biochemical characterization of a novel oxidatively stable, halotolerant, and high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T},
  series = {FEBS Open Bio},
  volume    = {12},
  journal   = {FEBS Open Bio},
  number    = {10},
  publisher = {Wiley},
  address   = {Hoboken, NJ},
  issn      = {2211-5463},
  doi       = {10.1002/2211-5463.13457},
  pages     = {1729 -- 1746},
  year      = {2022},
  abstract  = {Halophilic and halotolerant microorganisms represent a promising source of salt-tolerant enzymes suitable for various biotechnological applications where high salt concentrations would otherwise limit enzymatic activity. Considering the current growing enzyme market and the need for more efficient and new biocatalysts, the present study aimed at the characterization of a high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T. The protease gene was cloned and expressed in Bacillus subtilis DB104. The recombinant protease SPAO with 269 amino acids belongs to the subfamily of high-alkaline subtilisins. The biochemical characteristics of purified SPAO were analyzed in comparison with subtilisin Carlsberg, Savinase, and BPN'. SPAO, a monomer with a molecular mass of 27.1 kDa, was active over a wide range of pH 6.0-12.0 and temperature 20-80 °C, optimally at pH 9.0-9.5 and 55 °C. The protease is highly oxidatively stable to hydrogen peroxide and retained 58\% of residual activity when incubated at 10 °C with 5\% (v/v) H2O2 for 1 h while stimulated at 1\% (v/v) H2O2. Furthermore, SPAO was very stable and active at NaCl concentrations up to 5.0 m. This study demonstrates the potential of SPAO for biotechnological applications in the future.},
  language  = {en}
}
@article{PourshahidiEngelmannOffenhaeusseretal.2022,
  author    = {Pourshahidi, Ali Mohammad and Engelmann, Ulrich M. and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim},
  title     = {Resolving ambiguities in core size determination of magnetic nanoparticles from magnetic frequency mixing data},
  series = {Journal of Magnetism and Magnetic Materials},
  volume    = {563},
  journal   = {Journal of Magnetism and Magnetic Materials},
  number    = {In progress, Art. No. 169969},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0304-8853},
  doi       = {10.1016/j.jmmm.2022.169969},
  year      = {2022},
  abstract  = {Frequency mixing magnetic detection (FMMD) has been widely utilized as a measurement technique in magnetic immunoassays. It can also be used for the characterization and distinction (also known as "colourization") of different types of magnetic nanoparticles (MNPs) based on their core sizes. In a previous work, it was shown that the large particles contribute most of the FMMD signal. This leads to ambiguities in core size determination from fitting since the contribution of the small-sized particles is almost undetectable among the strong responses from the large ones. In this work, we report on how this ambiguity can be overcome by modelling the signal intensity using the Langevin model in thermodynamic equilibrium including a lognormal core size distribution fL(dc,d0,σ) fitted to experimentally measured FMMD data of immobilized MNPs. For each given median diameter d0, an ambiguous amount of best-fitting pairs of parameters distribution width σ and number of particles Np with R2 > 0.99 are extracted. By determining the samples' total iron mass, mFe, with inductively coupled plasma optical emission spectrometry (ICP-OES), we are then able to identify the one specific best-fitting pair (σ, Np) one uniquely. With this additional externally measured parameter, we resolved the ambiguity in core size distribution and determined the parameters (d0, σ, Np) directly from FMMD measurements, allowing precise MNPs sample characterization.},
  language  = {en}
}
@article{EngelmannPourshahidiShalabyetal.2022,
  author    = {Engelmann, Ulrich M. and Pourshahidi, Mohammad Ali and Shalaby, Ahmed and Krause, Hans-Joachim},
  title     = {Probing particle size dependency of frequency mixing magnetic detection with dynamic relaxation simulation},
  series = {Journal of Magnetism and Magnetic Materials},
  volume    = {563},
  journal   = {Journal of Magnetism and Magnetic Materials},
  number    = {In progress, Art. No. 169965},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0304-8853},
  doi       = {10.1016/j.jmmm.2022.169965},
  year      = {2022},
  abstract  = {Biomedical applications of magnetic nanoparticles (MNP) fundamentally rely on the particles' magnetic relaxation as a response to an alternating magnetic field. The magnetic relaxation complexly depends on the interplay of MNP magnetic and physical properties with the applied field parameters. It is commonly accepted that particle core size is a major contributor to signal generation in all the above applications, however, most MNP samples comprise broad distribution spanning nm and more. Therefore, precise knowledge of the exact contribution of individual core sizes to signal generation is desired for optimal MNP design generally for each application. Specifically, we present a magnetic relaxation simulation-driven analysis of experimental frequency mixing magnetic detection (FMMD) for biosensing to quantify the contributions of individual core size fractions towards signal generation. Applying our method to two different experimental MNP systems, we found the most dominant contributions from approx. 20 nm sized particles in the two independent MNP systems. Additional comparison between freely suspended and immobilized MNP also reveals insight in the MNP microstructure, allowing to use FMMD for MNP characterization, as well as to further fine-tune its applicability in biosensing.},
  language  = {en}
}
@article{FalkenbergBottBongaertsetal.2022,
  author    = {Falkenberg, Fabian and Bott, Michael and Bongaerts, Johannes and Siegert, Petra},
  title     = {Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae},
  series = {Frontiers in Microbiology},
  volume    = {2022},
  journal   = {Frontiers in Microbiology},
  number    = {13},
  publisher = {Frontiers},
  address   = {Lausanne},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2022.1017978},
  pages     = {Artikel 13:1017978},
  year      = {2022},
  abstract  = {The subtilase family (S8), a member of the clan SB of serine proteases are ubiquitous in all kingdoms of life and fulfil different physiological functions. Subtilases are divided in several groups and especially subtilisins are of interest as they are used in various industrial sectors. Therefore, we searched for new subtilisin sequences of the family Bacillaceae using a data mining approach. The obtained 1,400 sequences were phylogenetically classified in the context of the subtilase family. This required an updated comprehensive overview of the different groups within this family. To fill this gap, we conducted a phylogenetic survey of the S8 family with characterised holotypes derived from the MEROPS database. The analysis revealed the presence of eight previously uncharacterised groups and 13 subgroups within the S8 family. The sequences that emerged from the data mining with the set filter parameters were mainly assigned to the subtilisin subgroups of true subtilisins, high-alkaline subtilisins, and phylogenetically intermediate subtilisins and represent an excellent source for new subtilisin candidates.},
  language  = {en}
}
@article{HaegerBongaertsSiegert2022,
  author    = {Haeger, Gerrit and Bongaerts, Johannes and Siegert, Petra},
  title     = {A convenient ninhydrin assay in 96-well format for amino acid-releasing enzymes using an air-stable reagent},
  series = {Analytical Biochemistry},
  journal   = {Analytical Biochemistry},
  number    = {624},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1096-0309},
  doi       = {10.1016/j.ab.2022.114819},
  pages     = {Artikel 114819},
  year      = {2022},
  abstract  = {An improved and convenient ninhydrin assay for aminoacylase activity measurements was developed using the commercial EZ Nin™ reagent. Alternative reagents from literature were also evaluated and compared. The addition of DMSO to the reagent enhanced the solubility of Ruhemann's purple (RP). Furthermore, we found that the use of a basic, aqueous buffer enhances stability of RP. An acidic protocol for the quantification of lysine was developed by addition of glacial acetic acid. The assay allows for parallel processing in a 96-well format with measurements microtiter plates.},
  language  = {en}
}
@article{WeldenSeverinsPoghossianetal.2022,
  author    = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Bongaerts, Johannes and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor},
  series = {Chemosensors},
  volume    = {10},
  journal   = {Chemosensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2227-9040},
  doi       = {10.3390/chemosensors10060218},
  pages     = {Artikel 218},
  year      = {2022},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{WeldenSeverinsPoghossianetal.2022,
  author    = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Studying the immobilization of acetoin reductase with Tobacco mosaic virus particles on capacitive field-effect sensors},
  series = {2022 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN)},
  booktitle = {2022 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN)},
  publisher = {IEEE},
  isbn      = {978-1-6654-5860-3 (Online)},
  doi       = {10.1109/ISOEN54820.2022.9789657},
  pages     = {4 Seiten},
  year      = {2022},
  abstract  = {A capacitive electrolyte-insulator-semiconductor (EISCAP) biosensor modified with Tobacco mosaic virus (TMV) particles for the detection of acetoin is presented. The enzyme acetoin reductase (AR) was immobilized on the surface of the EISCAP using TMV particles as nanoscaffolds. The study focused on the optimization of the TMV-assisted AR immobilization on the Ta 2 O 5 -gate EISCAP surface. The TMV-assisted acetoin EISCAPs were electrochemically characterized by means of leakage-current, capacitance-voltage, and constant-capacitance measurements. The TMV-modified transducer surface was studied via scanning electron microscopy.},
  language  = {en}
}
@article{WeldenPoghossianVahidpouretal.2022,
  author    = {Welden, Melanie and Poghossian, Arshak and Vahidpour, Farnoosh and Wendlandt, Tim and Keusgen, Michael and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {Towards multi-analyte detection with field-effect capacitors modified with tobacco mosaic virus bioparticles as enzyme nanocarriers},
  series = {Biosensors},
  volume    = {12},
  journal   = {Biosensors},
  number    = {1},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios12010043},
  pages     = {Artikel 43},
  year      = {2022},
  abstract  = {Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1-3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate.},
  language  = {en}
}
@article{WeldenJablonskiWegeetal.2021,
  author    = {Welden, Rene and Jablonski, Melanie and Wege, Christina and Keusgen, Michael and Wagner, Patrick Hermann and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase},
  series = {Biosensors},
  volume    = {11},
  journal   = {Biosensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios11060171},
  pages     = {Artikel 171},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{SchoeningBronderWuetal.2017,
  author    = {Sch{\"o}ning, Michael Josef and Bronder, Thomas and Wu, Chunsheng and Scheja, Sabrina and Jessing, Max and Metzger-Boddien, Christoph and Keusgen, Michael and Poghossian, Arshak},
  title     = {Label-Free DNA Detection with Capacitive Field-Effect Devices—Challenges and Opportunities},
  series = {Proceedings},
  volume    = {1},
  journal   = {Proceedings},
  number    = {8},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2504-3900},
  doi       = {10.3390/proceedings1080719},
  pages     = {Artikel 719},
  year      = {2017},
  abstract  = {Field-effect EIS (electrolyte-insulator-semiconductor) sensors modified with a positively charged weak polyelectrolyte layer have been applied for the electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge. The EIS sensors are able to detect the existence of target DNA amplicons in PCR (polymerase chain reaction) samples and thus, can be used as tool for a quick verification of DNA amplification and the successful PCR process. Due to their miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge, those sensors can serve as possible platform for the development of label-free DNA chips. Possible application fields as well as challenges and limitations will be discussed.},
  language  = {en}
}
@article{BertzSchoeningMolinnusetal.2024,
  author    = {Bertz, Morten and Sch{\"o}ning, Michael Josef and Molinnus, Denise and Homma, Takayuki},
  title     = {Influence of temperature, light, and H₂O₂ concentration on microbial spore inactivation: in-situ Raman spectroscopy combined with optical trapping},
  series = {Physica status solidi (a) applications and materials science},
  journal   = {Physica status solidi (a) applications and materials science},
  number    = {Early View},
  publisher = {Wiley-VCH},
  address   = {Berlin},
  issn      = {1862-6319 (Online)},
  doi       = {10.1002/pssa.202300866},
  pages     = {8 Seiten},
  year      = {2024},
  abstract  = {To gain insight on chemical sterilization processes, the influence of temperature (up to 70 °C), intense green light, and hydrogen peroxide (H₂O₂) concentration (up to 30\% in aqueous solution) on microbial spore inactivation is evaluated by in-situ Raman spectroscopy with an optical trap. Bacillus atrophaeus is utilized as a model organism. Individual spores are isolated and their chemical makeup is monitored under dynamically changing conditions (temperature, light, and H₂O₂ concentration) to mimic industrially relevant process parameters for sterilization in the field of aseptic food processing. While isolated spores in water are highly stable, even at elevated temperatures of 70 °C, exposure to H₂O₂ leads to a loss of spore integrity characterized by the release of the key spore biomarker dipicolinic acid (DPA) in a concentration-dependent manner, which indicates damage to the inner membrane of the spore. Intensive light or heat, both of which accelerate the decomposition of H₂O₂ into reactive oxygen species (ROS), drastically shorten the spore lifetime, suggesting the formation of ROS as a rate-limiting step during sterilization. It is concluded that Raman spectroscopy can deliver mechanistic insight into the mode of action of H₂O₂-based sterilization and reveal the individual contributions of different sterilization methods acting in tandem.},
  language  = {en}
}
@article{EngelmannSimsekShalabyetal.2024,
  author    = {Engelmann, Ulrich M. and Simsek, Beril and Shalaby, Ahmed and Krause, Hans-Joachim},
  title     = {Key contributors to signal generation in frequency mixing magnetic detection (FMMD): an in silico study},
  series = {Sensors},
  volume    = {24},
  journal   = {Sensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s24061945},
  pages     = {Artikel 1945},
  year      = {2024},
  abstract  = {Frequency mixing magnetic detection (FMMD) is a sensitive and selective technique to detect magnetic nanoparticles (MNPs) serving as probes for binding biological targets. Its principle relies on the nonlinear magnetic relaxation dynamics of a particle ensemble interacting with a dual frequency external magnetic field. In order to increase its sensitivity, lower its limit of detection and overall improve its applicability in biosensing, matching combinations of external field parameters and internal particle properties are being sought to advance FMMD. In this study, we systematically probe the aforementioned interaction with coupled N{\´e}el-Brownian dynamic relaxation simulations to examine how key MNP properties as well as applied field parameters affect the frequency mixing signal generation. It is found that the core size of MNPs dominates their nonlinear magnetic response, with the strongest contributions from the largest particles. The drive field amplitude dominates the shape of the field-dependent response, whereas effective anisotropy and hydrodynamic size of the particles only weakly influence the signal generation in FMMD. For tailoring the MNP properties and parameters of the setup towards optimal FMMD signal generation, our findings suggest choosing large particles of core sizes dc > 25 nm nm with narrow size distributions (σ < 0.1) to minimize the required drive field amplitude. This allows potential improvements of FMMD as a stand-alone application, as well as advances in magnetic particle imaging, hyperthermia and magnetic immunoassays.},
  language  = {en}
}
@article{ReisertSchneiderGeissleretal.2013,
  author    = {Reisert, Steffen and Schneider, Benno and Geissler, Hanno and Gompel, Matthias van and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Multi-sensor chip for the investigation of different types of metal oxides for the detection of H2O2 in the ppm range},
  series = {physica status solidi (a)},
  volume    = {210},
  journal   = {physica status solidi (a)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  pages     = {898 -- 904},
  year      = {2013},
  abstract  = {In this work, a multi-sensor chip for the investigation of the sensing properties of different types of metal oxides towards hydrogen peroxide in the ppm range is presented. The fabrication process and physical characterization of the multi-sensor chip are described. Pure SnO2 and WO3 as well as Pd- and Pt-doped SnO2 films are characterized in terms of their sensitivity to H2O2. The sensing films have been prepared by drop-coating of water-dispensed nano-powders. A physical characterization, including scanning electron microscopy and X-ray diffraction analysis of the deposited metal-oxide films, was done. From the measurements in hydrogen peroxide atmosphere, it could be shown, that all of the tested metal oxide films are suitable for the detection of H2O2 in the ppm range. The highest sensitivity and reproducibility was achieved using Pt-doped SnO2. Calibration plot of a SnO2, WO3, Pt-, and Pd-doped SnO2 gas sensor for H2O2 concentrations in the ppm range.},
  language  = {en}
}
@article{PoghossianSchoening2014,
  author    = {Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Label-free sensing of biomolecules with field-effect devices for clinical applications},
  series = {Electroanalysis},
  volume    = {26},
  journal   = {Electroanalysis},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-4109 (E-Journal); 1040-0397 (Print)},
  doi       = {10.1002/elan.201400073},
  pages     = {1197 -- 1213},
  year      = {2014},
  abstract  = {Among the variety of transducer concepts proposed for label-free detection of biomolecules, the semiconductor field-effect device (FED) is one of the most attractive platforms. As medical techniques continue to progress towards diagnostic and therapies based on biomarkers, the ability of FEDs for a label-free, fast and real-time detection of multiple pathogenic and physiologically relevant molecules with high specificity and sensitivity offers very promising prospects for their application in point-of-care and personalized medicine for an early diagnosis and treatment of diseases. The presented paper reviews recent advances and current trends in research and development of different FEDs for label-free, direct electrical detection of charged biomolecules by their intrinsic molecular charge. The authors are mainly focusing on the detection of the DNA hybridization event, antibody-antigen affinity reaction as well as clinically relevant biomolecules such as cardiac and cancer biomarkers.},
  language  = {en}
}
@article{OberlaenderKirchnerBoyenetal.2014,
  author    = {Oberl{\"a}nder, Jan and Kirchner, Patrick and Boyen, Hans-Gerd and Sch{\"o}ning, Michael Josef},
  title     = {Detection of hydrogen peroxide vapor by use of manganese(IV) oxide as catalyst for calorimetric gas sensors},
  series = {Physica status solidi A: Applications and materials science},
  volume    = {211},
  journal   = {Physica status solidi A: Applications and materials science},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-396X (E-Journal); 1862-6319 (E-Journal); 0031-8965 (Print); 1862-6300 (Print)},
  doi       = {10.1002/pssa.201330359},
  pages     = {1372 -- 1376},
  year      = {2014},
  abstract  = {In this work, the catalyst manganese(IV) oxide (MnO2), of calorimetric gas sensors (to monitor the sterilization agent vaporized hydrogen peroxide) has been investigated in more detail. Chemical analyses by means of X-ray-induced photoelectron spectroscopy have been performed to unravel the surface chemistry prior and after exposure to hydrogen peroxide vapor at elevated temperature, as applied in the sterilization processes of beverage cartons. The surface characterization reveals a change in oxidation states of the metal oxide catalyst after exposure to hydrogen peroxide. Additionally, a cleaning effect of the catalyst, which itself is attached to the sensor surface by means of a polymer interlayer, could be observed.},
  language  = {en}
}
@article{WernerTakenagaTakietal.2013,
  author    = {Werner, Frederik and Takenaga, Shoko and Taki, Hidenori and Sawada, Kazuaki and Sch{\"o}ning, Michael Josef},
  title     = {Comparison of label-free ACh-imaging sensors based on CCD and LAPS},
  series = {Sensors and Actuators B: Chemical (2012)},
  volume    = {177},
  journal   = {Sensors and Actuators B: Chemical (2012)},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {0925-4005},
  pages     = {745 -- 752},
  year      = {2013},
  abstract  = {Semiconductor-based chemical imaging sensors, like the light-addressable potentiometric sensor (LAPS) or the pH-imaging sensor based on a charge-coupled device (CCD), are becoming a powerful tool for label-free imaging of biological phenomena. We have proposed a polyion-based enzymatic membrane to develop an acetylcholine (ACh) imaging sensor for neural cell-activity observations. In this study, a CCD-type ACh-imaging sensor and a LAPS-type ACh-imaging sensor were fabricated and the prospect of both sensors was clarified by making a comparison of their basic characteristics.},
  language  = {en}
}
@article{PoghossianJablonskiMolinnusetal.2020,
  author    = {Poghossian, Arshak and Jablonski, Melanie and Molinnus, Denise and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {Field-Effect Sensors for Virus Detection: From Ebola to SARS-CoV-2 and Plant Viral Enhancers},
  series = {Frontiers in Plant Science},
  volume    = {11},
  journal   = {Frontiers in Plant Science},
  number    = {Article 598103},
  publisher = {Frontiers},
  address   = {Lausanne},
  doi       = {10.3389/fpls.2020.598103},
  pages     = {1 -- 14},
  year      = {2020},
  abstract  = {Coronavirus disease 2019 (COVID-19) is a novel human infectious disease provoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, no specific vaccines or drugs against COVID-19 are available. Therefore, early diagnosis and treatment are essential in order to slow the virus spread and to contain the disease outbreak. Hence, new diagnostic tests and devices for virus detection in clinical samples that are faster, more accurate and reliable, easier and cost-efficient than existing ones are needed. Due to the small sizes, fast response time, label-free operation without the need for expensive and time-consuming labeling steps, the possibility of real-time and multiplexed measurements, robustness and portability (point-of-care and on-site testing), biosensors based on semiconductor field-effect devices (FEDs) are one of the most attractive platforms for an electrical detection of charged biomolecules and bioparticles by their intrinsic charge. In this review, recent advances and key developments in the field of label-free detection of viruses (including plant viruses) with various types of FEDs are presented. In recent years, however, certain plant viruses have also attracted additional interest for biosensor layouts: Their repetitive protein subunits arranged at nanometric spacing can be employed for coupling functional molecules. If used as adapters on sensor chip surfaces, they allow an efficient immobilization of analyte-specific recognition and detector elements such as antibodies and enzymes at highest surface densities. The display on plant viral bionanoparticles may also lead to long-time stabilization of sensor molecules upon repeated uses and has the potential to increase sensor performance substantially, compared to conventional layouts. This has been demonstrated in different proof-of-concept biosensor devices. Therefore, richly available plant viral particles, non-pathogenic for animals or humans, might gain novel importance if applied in receptor layers of FEDs. These perspectives are explained and discussed with regard to future detection strategies for COVID-19 and related viral diseases.},
  language  = {en}
}
@article{PoghossianSchoening2020,
  author    = {Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Capacitive field-effect eis chemical sensors and biosensors: A status report},
  series = {Sensors},
  volume    = {20},
  journal   = {Sensors},
  number    = {19},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s20195639},
  pages     = {Artikel 5639},
  year      = {2020},
  abstract  = {Electrolyte-insulator-semiconductor (EIS) field-effect sensors belong to a new generation of electronic chips for biochemical sensing, enabling a direct electronic readout. The review gives an overview on recent advances and current trends in the research and development of chemical sensors and biosensors based on the capacitive field-effect EIS structure—the simplest field-effect device, which represents a biochemically sensitive capacitor. Fundamental concepts, physicochemical phenomena underlying the transduction mechanism and application of capacitive EIS sensors for the detection of pH, ion concentrations, and enzymatic reactions, as well as the label-free detection of charged molecules (nucleic acids, proteins, and polyelectrolytes) and nanoparticles, are presented and discussed.},
  language  = {en}
}
@book{YoshinobuSchoening2020,
  author    = {Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef},
  title     = {Light-addressing and chemical imaging technologies for electrochemical sensing},
  editor    = {Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef},
  publisher = {MDPI},
  address   = {Basel},
  isbn      = {978-3-03943-029-1},
  doi       = {10.3390/books978-3-03943-029-1},
  pages     = {122 Pages},
  year      = {2020},
  language  = {en}
}
@article{PoghossianSchoening2021,
  author    = {Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Recent progress in silicon-based biologically sensitive field-effect devices},
  series = {Current Opinion in Electrochemistry},
  journal   = {Current Opinion in Electrochemistry},
  number    = {Article number: 100811},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2451-9103},
  doi       = {10.1016/j.coelec.2021.100811},
  year      = {2021},
  abstract  = {Biologically sensitive field-effect devices (BioFEDs) advantageously combine the electronic field-effect functionality with the (bio)chemical receptor's recognition ability for (bio)chemical sensing. In this review, basic and widely applied device concepts of silicon-based BioFEDs (ion-sensitive field-effect transistor, silicon nanowire transistor, electrolyte-insulator-semiconductor capacitor, light-addressable potentiometric sensor) are presented and recent progress (from 2019 to early 2021) is discussed. One of the main advantages of BioFEDs is the label-free sensing principle enabling to detect a large variety of biomolecules and bioparticles by their intrinsic charge. The review encompasses applications of BioFEDs for the label-free electrical detection of clinically relevant protein biomarkers, deoxyribonucleic acid molecules and viruses, enzyme-substrate reactions as well as recording of the cell acidification rate (as an indicator of cellular metabolism) and the extracellular potential.},
  language  = {en}
}
@article{MolinnusJanusFangetal.2022,
  author    = {Molinnus, Denise and Janus, Kevin Alexander and Fang, Anyelina C. and Drinic, Aleksander and Achtsnicht, Stefan and K{\"o}pf, Marius and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Thick-film carbon electrode deposited onto a biodegradable fibroin substrate for biosensing applications},
  series = {Physica status solidi (a)},
  volume    = {219},
  journal   = {Physica status solidi (a)},
  number    = {23},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.202200100},
  pages     = {1 -- 9},
  year      = {2022},
  abstract  = {This study addresses a proof-of-concept experiment with a biocompatible screen-printed carbon electrode deposited onto a biocompatible and biodegradable substrate, which is made of fibroin, a protein derived from silk of the Bombyx mori silkworm. To demonstrate the sensor performance, the carbon electrode is functionalized as a glucose biosensor with the enzyme glucose oxidase and encapsulated with a silicone rubber to ensure biocompatibility of the contact wires. The carbon electrode is fabricated by means of thick-film technology including a curing step to solidify the carbon paste. The influence of the curing temperature and curing time on the electrode morphology is analyzed via scanning electron microscopy. The electrochemical characterization of the glucose biosensor is performed by amperometric/voltammetric measurements of different glucose concentrations in phosphate buffer. Herein, systematic studies at applied potentials from 500 to 1200 mV to the carbon working electrode (vs the Ag/AgCl reference electrode) allow to determine the optimal working potential. Additionally, the influence of the curing parameters on the glucose sensitivity is examined over a time period of up to 361 days. The sensor shows a negligible cross-sensitivity toward ascorbic acid, noradrenaline, and adrenaline. The developed biocompatible biosensor is highly promising for future in vivo and epidermal applications.},
  language  = {en}
}
@article{PoghossianWeilCherstvyetal.2013,
  author    = {Poghossian, Arshak and Weil, M. and Cherstvy, A. G. and Sch{\"o}ning, Michael Josef},
  title     = {Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices},
  series = {Analytical and bioanalytical chemistry},
  volume    = {405},
  journal   = {Analytical and bioanalytical chemistry},
  number    = {20},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1432-1130 ; 1618-2642},
  doi       = {10.1007/s00216-013-6951-9},
  pages     = {6425 -- 6436},
  year      = {2013},
  abstract  = {The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance-voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed.},
  language  = {en}
}