@article{KirchnerOberlaenderFriedrichetal.2012,
  author    = {Kirchner, Patrick and Oberl{\"a}nder, Jan and Friedrich, Peter and Berger, J{\"o}rg and Rysstad, Gunnar and Sch{\"o}ning, Michael Josef and Keusgen, Michael},
  title     = {Realisation of a calorimetric gas sensor on polyimide foil for applications in aseptic food industry},
  series = {Sensors and Actuators B: Chemical},
  volume    = {170},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2011.01.032},
  pages     = {60 -- 66},
  year      = {2012},
  abstract  = {A calorimetric gas sensor is presented for the monitoring of vapour-phase H2O2 at elevated temperature during sterilisation processes in aseptic food industry. The sensor was built up on a flexible polyimide foil (thickness: 25 μm) that has been chosen due to its thermal stability and low thermal conductivity. The sensor set-up consists of two temperature-sensitive platinum thin-film resistances passivated by a layer of SU-8 photo resist and catalytically activated by manganese(IV) oxide. Instead of an active heating structure, the calorimetric sensor utilises the elevated temperature of the evaporated H2O2 aerosol. In an experimental test rig, the sensor has shown a sensitivity of 4.78 °C/(\%, v/v) in a H2O2 concentration range of 0\%, v/v to 8\%, v/v. Furthermore, the sensor possesses the same, unchanged sensor signal even at varied medium temperatures between 210 °C and 270 °C of the gas stream. At flow rates of the gas stream from 8 m3/h to 12 m3/h, the sensor has shown only a slightly reduced sensitivity at a low flow rate of 8 m3/h. The sensor characterisation demonstrates the suitability of the calorimetric gas sensor for monitoring the efficiency of industrial sterilisation processes.},
  language  = {en}
}
@article{MuribTranCeunincketal.2012,
  author    = {Murib, Mohammed S. and Tran, Anh Quang and Ceuninck, Ward de and Sch{\"o}ning, Michael Josef and Nesladek, Milos and Serpeng{\"u}zel, Ali and Wagner, Patrick},
  title     = {Analysis of an optical biosensor based on elastic light scattering from diamond-, glass-, and sapphire microspheres},
  series = {Physica Status Solidi A},
  volume    = {209},
  journal   = {Physica Status Solidi A},
  number    = {9},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201100795},
  pages     = {1804 -- 1810},
  year      = {2012},
  abstract  = {Deoxyribonucleic acid (DNA) and protein recognition are now standard tools in biology. In addition, the special optical properties of microsphere resonators expressed by the high quality factor (Q-factor) of whispering gallery modes (WGMs) or morphology dependent resonances (MDRs) have attracted the attention of the biophotonic community. Microsphere-based biosensors are considered as powerful candidates to achieve label-free recognition of single molecules due to the high sensitivity of their WGMs. When the microsphere surface is modified with biomolecules, the effective refractive index and the effective size of the microsphere change resulting in a resonant wavelength shift. The transverse electric (TE) and the transverse magnetic (TM) elastic light scattering intensity of electromagnetic waves at 600 and 1400 nm are numerically calculated for DNA and unspecific binding of proteins to the microsphere surface. The effect of changing the optical properties was studied for diamond (refractive index 2.34), glass (refractive index 1.50), and sapphire (refractive index 1.75) microspheres with a 50 µm radius. The mode spacing, the linewidth of WGMs, and the shift of resonant wavelength due to the change in radius and refractive index, were analyzed by numerical simulations. Preliminary results of unspecific binding of biomolecules are presented. The calculated shift in WGMs can be used for biomolecules detection.},
  language  = {en}
}
@article{IkenKirsanovLeginetal.2012,
  author    = {Iken, Heiko and Kirsanov, D. and Legin, A. and Sch{\"o}ning, Michael Josef},
  title     = {Novel Thin-Film Polymeric Materials for the Detection of Heavy Metals},
  series = {Procedia Engineering},
  journal   = {Procedia Engineering},
  number    = {47},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2012.09.148},
  pages     = {322 -- 325},
  year      = {2012},
  abstract  = {A variety of transition metals, e.g., copper, zinc, cadmium, lead, etc. are widely used in industry as components for wires, coatings, alloys, batteries, paints and so on. The inevitable presence of transition metals in industrial processes implies the ambition of developing a proper analytical technique for their adequate monitoring. Most of these elements, especially lead and cadmium, are acutely toxic for biological organisms. Quantitative determination of these metals at low activity levels in different environmental and industrial samples is therefore a vital task. A promising approach to achieve an at-side or on-line monitoring on a miniaturized and cost efficient way is the combination of a common potentiometric sensor array with heavy metal-sensitive thin-film materials, like chalcogenide glasses and polymeric materials, respectively.},
  language  = {en}
}
@article{MiyamotoIchimuraWagneretal.2012,
  author    = {Miyamoto, K. and Ichimura, H. and Wagner, Torsten and Yoshinobu, T. and Sch{\"o}ning, Michael Josef},
  title     = {Chemical Imaging of ion Diffusion in a Microfluidic Channel},
  series = {Procedia Engineering},
  journal   = {Procedia Engineering},
  number    = {47},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2012.09.289},
  pages     = {886 -- 889},
  year      = {2012},
  abstract  = {The chemical imaging sensor is a chemical sensor which is capable of visualizing the spatial distribution of chemical species in sample solution. In this study, a novel measurement system based on the chemical imaging sensor was developed to observe the inside of a Y-shaped microfluidic channel while injecting two sample solutions from two branches. From the collected chemical images, it was clearly observed that the injected solutions formed laminar flows in the microfluidic channel. In addition, ion diffusion across the laminar flows was observed. This label-free method can acquire quantitative data of ion distribution and diffusion in microfluidic devices, which can be used to determine the diffusion coefficients, and therefore, the molecular weights of chemical species in the sample solution.},
  language  = {en}
}
@article{WagnerShigiaharaMiyamotoetal.2012,
  author    = {Wagner, Torsten and Shigiahara, N. and Miyamoto, K. and Suzurikawa, J. and Finger, F. and Sch{\"o}ning, Michael Josef and Yoshinobu, T.},
  title     = {Light-addressable Potentiometric Sensors and Light-addressable Electrodes as a Combined Sensor-and-manipulator Microsystem with High Flexibility},
  series = {Procedia Engineering},
  journal   = {Procedia Engineering},
  number    = {47},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2012.09.290},
  pages     = {890 -- 893},
  year      = {2012},
  abstract  = {This work describes the novel combination of the light-addressable electrode (LAE) and the light-addressable potentiometric sensor (LAPS) into a microsystem set-up. Both the LAE as well as the LAPS shares the principle of addressing the active spot by means of a light beam. This enables both systems to manipulate resp. to detect an analyte with a high spatial resolution. Hence, combining both principles into a single set-up enables the active stimulation e.g., by means of electrolysis and a simultaneous observation e.g., the response of an entrapped biological cell by detection of extracellular pH changes. The work will describe the principles of both technologies and the necessary steps to integrate them into a single set-up. Furthermore, examples of application and operation of such systems will be presented.},
  language  = {en}
}
@article{PoghossianWeilBaeckeretal.2012,
  author    = {Poghossian, Arshak and Weil, M. H. and B{\"a}cker, Matthias and Mayer, D. and Sch{\"o}ning, Michael Josef},
  title     = {Field-effect Devices Functionalised with Gold-Nanoparticle/Macromolecule Hybrids: New Opportunities for a Label-Free Biosensing},
  series = {Procedia Engineering},
  journal   = {Procedia Engineering},
  number    = {47},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2012.09.136},
  pages     = {273 -- 276},
  year      = {2012},
  abstract  = {Field-effect capacitive electrolyte-insulator-semiconductor (EIS) sensors functionalised with citrate-capped gold nanoparticles (AuNP) have been used for the electrostatic detection of macromolecules by their intrinsic molecular charge. The EIS sensor detects the charge changes in the AuNP/macromolecule hybrids induced by the adsorption or binding events. A feasibility of the proposed detection scheme has been exemplary demonstrated by realising EIS sensors for the detection of poly-D-lysine molecules.},
  language  = {en}
}
@article{HuckPoghossianWagneretal.2012,
  author    = {Huck, Christina and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Combined amperometric/field-effect sensor for the detection of dissolved hydrogen},
  series = {Sensors and actuators B: Chemical},
  volume    = {187},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2012.10.050},
  pages     = {168 -- 173},
  year      = {2012},
  abstract  = {Real-time and reliable monitoring of the biogas process is crucial for a stable and efficient operation of biogas production in order to avoid digester breakdowns. The concentration of dissolved hydrogen (H₂) represents one of the key parameters for biogas process control. In this work, a one-chip integrated combined amperometric/field-effect sensor for monitoring the dissolved H₂ concentration has been developed for biogas applications. The combination of two different transducer principles might allow a more accurate and reliable measurement of dissolved H₂ as an early warning indicator of digester failures. The feasibility of the approach has been demonstrated by simultaneous amperometric/field-effect measurements of dissolved H₂ concentrations in electrolyte solutions. Both, the amperometric and the field-effect transducer show a linear response behaviour in the H₂ concentration range from 0.1 to 3\% (v/v) with a slope of 198.4 ± 13.7 nA/\% (v/v) and 14.9 ± 0.5 mV/\% (v/v), respectively.},
  language  = {en}
}
@article{SchoeningBiselliSelmeretal.2012,
  author    = {Sch{\"o}ning, Michael Josef and Biselli, Manfred and Selmer, Thorsten and {\"O}hlschl{\"a}ger, Peter and Baumann, Marcus and F{\"o}rster, Arnold and Poghossian, Arshak},
  title     = {Forschung „zwischen" den Disziplinen: das Institut f{\"u}r Nano- und Biotechnologien},
  series = {Analytik news : das Online-Labormagazin f{\"u}r Labor und Analytik},
  volume    = {Publ. online},
  journal   = {Analytik news : das Online-Labormagazin f{\"u}r Labor und Analytik},
  publisher = {Dr. Beyer Internet-Beratung},
  address   = {Ober-Ramstadt},
  pages     = {11 Seiten},
  year      = {2012},
  abstract  = {"Biologie trifft Mikroelektronik", das Motto des Instituts f{\"u}r Nano- und Biotechnologien (INB) an der FH Aachen, unterstreicht die zunehmende Bedeutung interdisziplin{\"a}r gepr{\"a}gter Forschungsaktivit{\"a}ten. Der thematische Zusammenschluss grundst{\"a}ndiger Disziplinen, wie die Physik, Elektrotechnik, Chemie, Biologie sowie die Materialwissenschaften, l{\"a}sst neue Forschungsgebiete entstehen, ein herausragendes Beispiel hierf{\"u}r ist die Nanotechnologie: Hier werden neue Werkstoffe und Materialien entwickelt, einzelne Nanopartikel oder Molek{\"u}le und deren Wechselwirkung untersucht oder Schichtstrukturen im Nanometerbereich aufgebaut, die neue und vorher nicht bekannte Eigenschaften hervorbringen. Vor diesem Hintergrund b{\"u}ndelt das im Jahre 2006 gegr{\"u}ndete INB die an der FH Aachen vorhandenen Kompetenzen von derzeit insgesamt sieben Laboratorien auf den Gebieten der Halbleitertechnik und Nanoelektronik, Nanostrukturen und DNA-Sensorik, der Chemo- und Biosensorik, der Enzymtechnologie, der Mikrobiologie und Pflanzenbiotechnologie, der Zellkulturtechnik, sowie der Roten Biotechnologie synergetisch. In der Nano- und Biotechnologie steckt außergew{\"o}hnliches Potenzial! Nicht zuletzt deshalb stellen sich die Forscher der Herausforderung, in diesem Bereich gemeinsam zu forschen und Schnittstellen zu nutzen, um so bei der Gestaltung neuartiger Ideen und Produkte mitzuwirken, die zuk{\"u}nftig unser allt{\"a}gliches Leben ver{\"a}ndern werden. Im Folgenden werden die verschiedenen Forschungsbereiche kurz zusammenfassend vorgestellt und vorhandene Interaktionen anhand von exemplarisch ausgew{\"a}hlten, aktuellen Forschungsprojekten skizziert.},
  language  = {de}
}
@article{SchoeningBaecker2012,
  author    = {Sch{\"o}ning, Michael Josef and B{\"a}cker, Matthias},
  title     = {Chip-basierte Sensoren f{\"u}r die Biotechnik},
  volume    = {13},
  number    = {2},
  publisher = {BIOCOM},
  address   = {Berlin},
  issn      = {1611-0854},
  year      = {2012},
  language  = {de}
}
@article{SpelthahnSchubertSchoening2012,
  author    = {Spelthahn, Heiko and Schubert, J{\"u}rgen and Sch{\"o}ning, Michael Josef},
  title     = {D{\"u}nnschichtsensoren f{\"u}r die Schwermetallanalytik : Mikroelektroden auf Chalkogenidglasbasis},
  series = {GIT Labor-Fachzeitschrift},
  journal   = {GIT Labor-Fachzeitschrift},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  pages     = {285 -- 287},
  year      = {2012},
  abstract  = {Die Detektion von Schadstoffen repr{\"a}sentiert in der Umweltanalytik eine wichtige Aufgabenstellung. Gerade die Abwasser- bzw. Brauchwasseranalytik sowie die Prozesskontrolle haben einen hohen Stellenwert. Siliziumbasierte D{\"u}nnschichtsensoren bieten eine kosteng{\"u}nstige M{\"o}glichkeit, „online"-Messungen bzw. Vor-Ort-Messungen zeitnah durchzuf{\"u}hren. In dieser Arbeit wird ein potentiometrisches Sensorarray auf der Basis von Chalkogenidgl{\"a}sern zur Detektion von Schwermetallen in w{\"a}ssrigen Medien vorgestellt.},
  language  = {de}
}
@article{BohrnStuetzFleischeretal.2013,
  author    = {Bohrn, Ulrich and St{\"u}tz, Evamaria and Fleischer, Maximilian and Sch{\"o}ning, Michael Josef and Wagner, Patrick},
  title     = {Using a cell-based gas biosensor for investigation of adverse effects of acetone vapors in vitro},
  series = {Biosensors and Bioelectronics. 40 (2013), H. 1},
  journal   = {Biosensors and Bioelectronics. 40 (2013), H. 1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {0956-5663},
  pages     = {393 -- 400},
  year      = {2013},
  language  = {en}
}
@article{MuribGrinsvenGrietenetal.2013,
  author    = {Murib, M. S. and Grinsven, B. van and Grieten, L. and Janssens, S. D. and Vermeeren, V. and Eersels, K. and Broeders, J. and Ameloot, M. and Michiels, L. and Ceuninck, W. De and Haenen, K. and Sch{\"o}ning, Michael Josef and Wagner, Patrick},
  title     = {Electronic monitoring of chemical DNA denaturation on nanocrystalline diamond electrodes with different molarities and flow rates},
  series = {Physica Status Solidi (A). Vol. 210 (2013), iss. 5},
  journal   = {Physica Status Solidi (A). Vol. 210 (2013), iss. 5},
  publisher = {Wiley-VCH},
  address   = {Berlin},
  issn      = {0031-8965},
  pages     = {911 -- 917},
  year      = {2013},
  language  = {en}
}
@article{BohrnMuchaWerneretal.2013,
  author    = {Bohrn, Ulrich and Mucha, Andreas and Werner, Frederik and Trattner, Barbara and B{\"a}cker, Matthias and Krumbe, Christoph and Schienle, Meinrad and St{\"u}tz, Evamaria and Schmitt-Landsiedel, Doris and Fleischer, Maximilian and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {A critical comparison of cell-based sensor systems for the detection of Cr (VI) in aquatic environment},
  series = {Sensors and actuators. B: Chemical},
  volume    = {Vol. 182},
  journal   = {Sensors and actuators. B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  pages     = {58 -- 65},
  year      = {2013},
  language  = {en}
}
@article{KramerHalamkovaPoghossianetal.2013,
  author    = {Kramer, Friederike and Halamkova, Lenka and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny and Halamek, Jan},
  title     = {Biocatalytic analysis of biomarkers for forensic identification of ethnicity between Caucasian and African American},
  series = {The analyst. August 2013},
  volume    = {Vol. 138},
  journal   = {The analyst. August 2013},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1364-5528 (E-Journal); 0003-2654 (Print)},
  pages     = {6251 -- 6257},
  year      = {2013},
  language  = {en}
}
@article{SchusserMenzelBaeckeretal.2013,
  author    = {Schusser, Sebastian and Menzel, S. and B{\"a}cker, Matthias and Leinhos, Marcel and Poghossian, Arshak and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Degradation of thin poly(lactic acid) films: characterization by capacitance-voltage, atomic force microscopy, scanning electron microscopy and contact-angle measurements},
  series = {Electrochimica Acta},
  volume    = {Vol. 113},
  journal   = {Electrochimica Acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3859 (E-Journal); 0013-4686 (Print)},
  pages     = {779 -- 784},
  year      = {2013},
  language  = {en}
}
@article{IkenAhlbornGerlachetal.2013,
  author    = {Iken, Heiko and Ahlborn, K. and Gerlach, F. and Vonau, W. and Zander, W. and Schubert, J. and Sch{\"o}ning, Michael Josef},
  title     = {Development of redox glasses and subsequent processing by means of pulsed laser deposition for realizing silicon-based thin-film sensors},
  series = {Electrochimica acta},
  journal   = {Electrochimica acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3859 (E-Journal); 0013-4686 (Print)},
  pages     = {Available online 30.8.2013},
  year      = {2013},
  language  = {en}
}
@article{ReisertGeisslerFloerkeetal.2013,
  author    = {Reisert, Steffen and Geissler, Hanno and Fl{\"o}rke, Rudolf and Weiler, Christian and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Characterisation of aseptic sterilisation processes using an electronic nose},
  series = {International journal of nanotechnology},
  volume    = {Vol. 10},
  journal   = {International journal of nanotechnology},
  number    = {No. 5-7},
  publisher = {Inderscience Enterprises},
  address   = {Gen{\`e}ve},
  issn      = {1475-7435 (Print) 7141-8151 (Online)},
  pages     = {470 -- 484},
  year      = {2013},
  language  = {en}
}
@article{MiyamotoHirayamaWagneretal.2013,
  author    = {Miyamoto, Ko-ichiro and Hirayama, Yuji and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Visualization of enzymatic reaction in a microfluidic channel using chemical imaging sensor},
  series = {Electrochimica acta},
  journal   = {Electrochimica acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3859 (E-Journal); 0013-4686 (Print)},
  pages     = {Publ. online},
  year      = {2013},
  language  = {en}
}
@article{BaeckerSchusserPoghossianetal.2013,
  author    = {B{\"a}cker, Matthias and Schusser, Sebastian and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Degradationsverhalten bioabbaubarer Polymere : siliziumbasierte Sensorik zur {\"U}berwachung},
  series = {GIT Labor-Fachzeitschrift},
  journal   = {GIT Labor-Fachzeitschrift},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0016-3538},
  pages     = {32 -- 33},
  year      = {2013},
  language  = {de}
}
@article{BuniatyanHuckPoghossianetal.2013,
  author    = {Buniatyan, V. and Huck, Christina and Poghossian, Arshak and Aroutiounian, V. M. and Sch{\"o}ning, Michael Josef},
  title     = {BaxSr1-x TiO3/pc-Si heterojunction capacitance},
  series = {Armenian journal of physics},
  volume    = {6},
  journal   = {Armenian journal of physics},
  number    = {4},
  publisher = {National Academy of Sciences of Armenia},
  address   = {Yerevan},
  issn      = {1829-1171},
  pages     = {188 -- 197},
  year      = {2013},
  language  = {en}
}
@article{BuniatyanHuckPoghossianetal.2013,
  author    = {Buniatyan, V. and Huck, Christina and Poghossian, Arshak and Aroutiounian, V. M. and Sch{\"o}ning, Michael Josef},
  title     = {BaxSr1-x TiO3/pc-Si heterojunction},
  series = {Armenian journal of physics},
  volume    = {6},
  journal   = {Armenian journal of physics},
  number    = {4},
  publisher = {National Academy of Sciences of Armenia},
  address   = {Yerevan},
  issn      = {1829-1171},
  pages     = {177 -- 187},
  year      = {2013},
  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{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{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}
}
@article{HuckSchiffelsHerreraetal.2013,
  author    = {Huck, Christina and Schiffels, Johannes and Herrera, Cony N. and Schelden, Maximilian and Selmer, Thorsten and Poghossian, Arshak and Baumann, Marcus and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Metabolic responses of Escherichia coli upon glucose pulses captured by a capacitive field-effect sensor},
  series = {Physica Status Solidi (A)},
  volume    = {210},
  journal   = {Physica Status Solidi (A)},
  number    = {5},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0031-8965},
  doi       = {10.1002/pssa.201200900},
  pages     = {926 -- 931},
  year      = {2013},
  abstract  = {Living cells are complex biological systems transforming metabolites taken up from the surrounding medium. Monitoring the responses of such cells to certain substrate concentrations is a challenging task and offers possibilities to gain insight into the vitality of a community influenced by the growth environment. Cell-based sensors represent a promising platform for monitoring the metabolic activity and thus, the "welfare" of relevant organisms. In the present study, metabolic responses of the model bacterium Escherichia coli in suspension, layered onto a capacitive field-effect structure, were examined to pulses of glucose in the concentration range between 0.05 and 2 mM. It was found that acidification of the surrounding medium takes place immediately after glucose addition and follows Michaelis-Menten kinetic behavior as a function of the glucose concentration. In future, the presented setup can, therefore, be used to study substrate specificities on the enzymatic level and may as well be used to perform investigations of more complex metabolic responses. Conclusions and perspectives highlighting this system are discussed.},
  language  = {en}
}
@article{BaeckerRakowskiPoghossianetal.2013,
  author    = {B{\"a}cker, Matthias and Rakowski, D. and Poghossian, Arshak and Biselli, Manfred and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Chip-based amperometric enzyme sensor system for monitoring of bioprocesses by flow-injection analysis},
  series = {Journal of Biotechnology},
  volume    = {163},
  journal   = {Journal of Biotechnology},
  number    = {4},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-1656},
  doi       = {10.1016/j.jbiotec.2012.03.014},
  pages     = {371 -- 376},
  year      = {2013},
  abstract  = {A microfluidic chip integrating amperometric enzyme sensors for the detection of glucose, glutamate and glutamine in cell-culture fermentation processes has been developed. The enzymes glucose oxidase, glutamate oxidase and glutaminase were immobilized by means of cross-linking with glutaraldehyde on platinum thin-film electrodes integrated within a microfluidic channel. The biosensor chip was coupled to a flow-injection analysis system for electrochemical characterization of the sensors. The sensors have been characterized in terms of sensitivity, linear working range and detection limit. The sensitivity evaluated from the respective peak areas was 1.47, 3.68 and 0.28 μAs/mM for the glucose, glutamate and glutamine sensor, respectively. The calibration curves were linear up to a concentration of 20 mM glucose and glutamine and up to 10 mM for glutamate. The lower detection limit amounted to be 0.05 mM for the glucose and glutamate sensor, respectively, and 0.1 mM for the glutamine sensor. Experiments in cell-culture medium have demonstrated a good correlation between the glutamate, glutamine and glucose concentrations measured with the chip-based biosensors in a differential-mode and the commercially available instrumentation. The obtained results demonstrate the feasibility of the realized microfluidic biosensor chip for monitoring of bioprocesses.},
  language  = {en}
}
@article{KirchnerOberlaenderSucoetal.2013,
  author    = {Kirchner, Patrick and Oberl{\"a}nder, Jan and Suco, Henri-Pierre and Rysstad, Gunnar and Sch{\"o}ning, Michael Josef},
  title     = {Monitoring the microbicidal effectiveness of gaseous hydrogen peroxide in sterilisation processes by means of a calorimetric gas sensor},
  series = {Food control},
  volume    = {31},
  journal   = {Food control},
  number    = {2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0956-7135},
  doi       = {10.1016/j.foodcont.2012.11.048},
  pages     = {530 -- 538},
  year      = {2013},
  abstract  = {In the present work, a novel method for monitoring sterilisation processes with gaseous H2O2 in combination with heat activation by means of a specially designed calorimetric gas sensor was evaluated. Therefore, the sterilisation process was extensively studied by using test specimens inoculated with Bacillus atrophaeus spores in order to identify the most influencing process factors on its microbicidal effectiveness. Besides the contact time of the test specimens with gaseous H2O2 varied between 0.2 and 0.5 s, the present H2O2 concentration in a range from 0 to 8\% v/v (volume percent) had a strong influence on the microbicidal effectiveness, whereas the change of the vaporiser temperature, gas flow and humidity were almost negligible. Furthermore, a calorimetric H2O2 gas sensor was characterised in the sterilisation process with gaseous H2O2 in a wide range of parameter settings, wherein the measurement signal has shown a linear response against the H2O2 concentration with a sensitivity of 4.75 °C/(\% v/v). In a final step, a correlation model by matching the measurement signal of the gas sensor with the microbial inactivation kinetics was established that demonstrates its suitability as an efficient method for validating the microbicidal effectiveness of sterilisation processes with gaseous H2O2.},
  language  = {en}
}
@article{KirchnerOberlaenderSusoetal.2013,
  author    = {Kirchner, Patrick and Oberl{\"a}nder, Jan and Suso, Henri-Pierre and Rysstad, Gunnar and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Towards a wireless sensor system for real-time H2O2 monitoring in aseptic food processes},
  series = {Physica status solidi (a)},
  volume    = {210},
  journal   = {Physica status solidi (a)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201200920},
  pages     = {877 -- 883},
  year      = {2013},
  abstract  = {A wireless sensor system based on the industrial ZigBee standard for low-rate wireless networking was developed that enables real-time monitoring of gaseous H2O2 during the package sterilization in aseptic food processes. The sensor system consists of a remote unit connected to a calorimetric gas sensor, which was already established in former works, and an external base unit connected to a laptop computer. The remote unit was built up by an XBee radio frequency (RF) module for data communication and a programmable system-on-chip controller to read out the sensor signal and process the sensor data, whereas the base unit is a second XBee RF module. For the rapid H2O2 detection on various locations inside the package that has to be sterilized, a novel read-out strategy of the calorimetric gas sensor was established, wherein the sensor response is measured within the short sterilization time and correlated with the present H2O2 concentration. In an exemplary measurement application in an aseptic filling machinery, the suitability of the new, wireless sensor system was demonstrated, wherein the influence of the gas velocity on the H2O2 distribution inside a package was determined and verified with microbiological tests.},
  language  = {en}
}
@article{HennemannKohlReisertetal.2013,
  author    = {Hennemann, J{\"o}rg and Kohl, Claus-Dieter and Reisert, Steffen and Kirchner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Copper oxide nanofibres for detection of hydrogen peroxide vapour at high concentrations},
  series = {physica status solidi (a)},
  volume    = {210},
  journal   = {physica status solidi (a)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201200775},
  pages     = {859 -- 863},
  year      = {2013},
  abstract  = {We present a sensor concept based on copper(II)oxide (CuO) nanofibres for the detection of hydrogen peroxide (H2O2) vapour in the percent per volume (\% v/v) range. The fibres were produced by using the electrospinning technique. To avoid water condensation in the pores, the fibres were initially modified by an exposure to H2S to get an enclosed surface. By a thermal treatment at 350 °C the fibres were oxidised back to CuO. Thereby, the visible pores disappear which was verified by SEM analysis. The fibres show a decrease of resistance with increasing H2O2 concentration which is due to the fact that hydrogen peroxide is an oxidising gas and CuO a p-type semiconductor. The sensor shows a change of resistance within the minute range to the exposure until the maximum concentration of 6.9\% v/v H2O2. At operating temperatures below 450 °C the corresponding sensor response to a concentration of 4.1\% v/v increases. The sensor shows a good reproducibility of the signal at different measurements. CuO seems to be a suitable candidate for the detection of H2O2 vapour at high concentrations. Resistance behaviour of the sensor under exposure to H2O2 vapours between 2.3 and 6.9\% v/v at an operating temperature of 450 °C.},
  language  = {en}
}
@article{SchusserLeinhosBaeckeretal.2013,
  author    = {Schusser, Sebastian and Leinhos, Marcel and B{\"a}cker, Matthias and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Impedance spectroscopy: A tool for real-time in situ monitoring of the degradation of biopolymers},
  series = {Physica Status Solidi (A)},
  volume    = {210},
  journal   = {Physica Status Solidi (A)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1521-396X ; 0031-8965},
  doi       = {10.1002/pssa.201200941},
  pages     = {905 -- 910},
  year      = {2013},
  abstract  = {Investigation of the degradation kinetics of biodegradable polymers is essential for the development of implantable biomedical devices with predicted biodegradability. In this work, an impedimetric sensor has been applied for real-time and in situ monitoring of degradation processes of biopolymers. The sensor consists of two platinum thin-film electrodes covered by a polymer film to be studied. The benchmark biomedical polymer poly(D,L-lactic acid) (PDLLA) was used as a model system. PDLLA films were deposited on the sensor structure from a polymer solution by using the spin-coating method. The degradation kinetics of PDLLA films have been studied in alkaline solutions of pH 9 and 12 by means of an impedance spectroscopy (IS) method. Any changes in a polymer capacitance/resistance induced by water uptake and/or polymer degradation will modulate the global impedance of the polymer-covered sensor that can be used as an indicator of the polymer degradation. The degradation rate can be evaluated from the time-dependent impedance spectra. As expected, a faster degradation has been observed for PDLLA films exposed to pH 12 solution.},
  language  = {en}
}
@article{ItabashiKosakaMiyamotoetal.2013,
  author    = {Itabashi, Akinori and Kosaka, Naoki and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {High-speed chemical imaging system based on front-side-illuminated LAPS},
  series = {Sensors and actuators B: Chemical},
  volume    = {182},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077},
  doi       = {10.1016/j.snb.2013.03.016},
  pages     = {315 -- 321},
  year      = {2013},
  abstract  = {The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the spatial distribution of specific ions on the sensing surface. The conventional chemical imaging system based on the light-addressable potentiometric sensor (LAPS), however, required a long time to obtain a chemical image, due to the slow mechanical scan of a single light beam. For high-speed imaging, a plurality of light beams modulated at different frequencies can be employed to measure the ion concentrations simultaneously at different locations on the sensor plate by frequency division multiplex (FDM). However, the conventional measurement geometry of back-side illumination limited the bandwidth of the modulation frequency required for FDM measurement, because of the low-pass filtering characteristics of carrier diffusion in the Si substrate. In this study, a high-speed chemical imaging system based on front-side-illuminated LAPS was developed, which achieved high-speed spatiotemporal recording of pH change at a rate of 70 frames per second.},
  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}
}
@article{MiyamotoIchimuraWagneretal.2013,
  author    = {Miyamoto, Ko-ichiro and Ichimura, Hiroki and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Chemical imaging of the concentration profile of ion diffusion in a microfluidic channel},
  series = {Sensors and actuators. B: Chemical},
  volume    = {189},
  journal   = {Sensors and actuators. B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2013.04.057},
  pages     = {240 -- 245},
  year      = {2013},
  abstract  = {The chemical imaging sensor is a device to visualize the spatial distribution of chemical species based on the principle of LAPS (light-addressable potentiometric sensor), which is a field-effect chemical sensor based on semiconductor. In this study, the chemical imaging sensor has been applied to investigate the ion profile of laminar flows in a microfluidic channel. The chemical images (pH maps) were collected in a Y-shaped microfluidic channel while injecting HCl and NaCl solutions into two branches. From the chemical images, it was clearly observed that the injected solutions formed laminar flows in the channel. In addition, ion diffusion across the laminar flows was observed, and the diffusion coefficient could be derived by fitting the pH profiles to the Fick's equation.},
  language  = {en}
}
@article{BandodkarMolinnusMirzaetal.2014,
  author    = {Bandodkar, Amay J. and Molinnus, Denise and Mirza, Omar and Guinovart, Tomas and Windmiller, Joshua R. and Valdes-Ramirez, Gabriela and Andrade, Francisco J. and Sch{\"o}ning, Michael Josef and Wang, Joseph},
  title     = {Epidermal tattoo potentiometric sodium sensors with wireless signal transduction for continuous non-invasive sweat monitoring},
  series = {Biosensors and bioelectronics},
  volume    = {54},
  journal   = {Biosensors and bioelectronics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4235 (E-Journal); 0956-5663 (Print)},
  doi       = {10.1016/j.bios.2013.11.039},
  pages     = {603 -- 609},
  year      = {2014},
  abstract  = {This article describes the fabrication, characterization and application of an epidermal temporary-transfer tattoo-based potentiometric sensor, coupled with a miniaturized wearable wireless transceiver, for real-time monitoring of sodium in the human perspiration. Sodium excreted during perspiration is an excellent marker for electrolyte imbalance and provides valuable information regarding an individual's physical and mental wellbeing. The realization of the new skin-worn non-invasive tattoo-like sensing device has been realized by amalgamating several state-of-the-art thick film, laser printing, solid-state potentiometry, fluidics and wireless technologies. The resulting tattoo-based potentiometric sodium sensor displays a rapid near-Nernstian response with negligible carryover effects, and good resiliency against various mechanical deformations experienced by the human epidermis. On-body testing of the tattoo sensor coupled to a wireless transceiver during exercise activity demonstrated its ability to continuously monitor sweat sodium dynamics. The real-time sweat sodium concentration was transmitted wirelessly via a body-worn transceiver from the sodium tattoo sensor to a notebook while the subjects perspired on a stationary cycle. The favorable analytical performance along with the wearable nature of the wireless transceiver makes the new epidermal potentiometric sensing system attractive for continuous monitoring the sodium dynamics in human perspiration during diverse activities relevant to the healthcare, fitness, military, healthcare and skin-care domains.},
  language  = {en}
}
@article{MiyamotoItabashiWagneretal.2014,
  author    = {Miyamoto, Ko-ichiro and Itabashi, Akinori and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {High-speed chemical imaging inside a microfluidic channel},
  series = {Sensors and actuators. B: Chemical},
  volume    = {194},
  journal   = {Sensors and actuators. B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2013.12.090},
  pages     = {521 -- 527},
  year      = {2014},
  abstract  = {In this study, a high-speed chemical imaging system was developed for visualization of the interior of a microfluidic channel. A microfluidic channel was constructed on the sensor surface of the light-addressable potentiometric sensor (LAPS), on which the ion concentrations could be measured in parallel at up to 64 points illuminated by optical fibers. The temporal change of pH distribution inside the microfluidic channel was recorded at a maximum rate of 100 frames per second (fps). The high frame rate allowed visualization of moving interfaces and plugs in the channel even at a flow velocity of 111 mm/s, which suggests the feasibility of plug-based microfluidic devices for flow-injection analysis (FIA).},
  language  = {en}
}
@article{MoseleyHalamekKrameretal.2014,
  author    = {Moseley, Fiona and Halamek, Jan and Kramer, Friederike and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {An enzyme-based reversible CNOT logic gate realized in a flow system},
  series = {Analyst},
  volume    = {139},
  journal   = {Analyst},
  number    = {8},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1364-5528 (E-Journal) ; 0003-2654 (Print)},
  doi       = {10.1039/C4AN00133H},
  pages     = {1839 -- 1842},
  year      = {2014},
  abstract  = {An enzyme system organized in a flow device was used to mimic a reversible Controlled NOT (CNOT) gate with two input and two output signals. Reversible conversion of NAD⁺ and NADH cofactors was used to perform a XOR logic operation, while biocatalytic hydrolysis of p-nitrophenyl phosphate resulted in an Identity operation working in parallel. The first biomolecular realization of a CNOT gate is promising for integration into complex biomolecular networks and future biosensor/biomedical applications.},
  language  = {en}
}
@article{LeinhosSchusserBaeckeretal.2014,
  author    = {Leinhos, Marcel and Schusser, Sebastian and B{\"a}cker, Matthias and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Micromachined multi-parameter sensor chip for the control of polymer-degradation medium},
  series = {Physica Status Solidi (A) : special issue on engineering and functional interfaces},
  volume    = {211},
  journal   = {Physica Status Solidi (A) : special issue on engineering and functional interfaces},
  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.201330364},
  pages     = {1346 -- 1351},
  year      = {2014},
  abstract  = {It is well known that the degradation environment can strongly influence the biodegradability and kinetics of biodegradation processes of polymers. Therefore, besides the monitoring of the degradation process, it is also necessary to control the medium in which the degradation takes place. In this work, a micromachined multi-parameter sensor chip for the control of the polymer-degradation medium has been developed. The chip combines a capacitive field-effect pH sensor, a four-electrode electrolyte-conductivity sensor and a thin-film Pt-temperature sensor. The results of characterization of individual sensors are presented. In addition, the multi-parameter sensor chip together with an impedimetric polymer-degradation sensor was simultaneously characterized in degradation solutions with different pH and electrolyte conductivity. The obtained results demonstrate the feasibility of the multi-parameter sensor chip for the control of the polymer-degradation medium.},
  language  = {en}
}
@article{HuckPoghossianKerroumietal.2014,
  author    = {Huck, Christina and Poghossian, Arshak and Kerroumi, Iman and Schusser, Sebastian and B{\"a}cker, Matthias and Zander, Willi and Schubert, J{\"u}rgen and Buniatyan, Vahe V. and Martirosyan, Norayr W. and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Multiparameter sensor chip with Barium Strontium Titanate as multipurpose material},
  series = {Electroanalysis},
  volume    = {26},
  journal   = {Electroanalysis},
  number    = {5},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-4109 (E-Journal); 1040-0397 (Print)},
  doi       = {10.1002/elan.201400076},
  pages     = {980 -- 987},
  year      = {2014},
  abstract  = {It is well known that biochemical and biotechnological processes are strongly dependent and affected by a variety of physico-chemical parameters such as pH value, temperature, pressure and electrolyte conductivity. Therefore, these quantities have to be monitored or controlled in order to guarantee a stable process operation, optimization and high yield. In this work, a sensor chip for the multiparameter detection of three physico-chemical parameters such as electrolyte conductivity, pH and temperature is realized using barium strontium titanate (BST) as multipurpose material. The chip integrates a capacitively coupled four-electrode electrolyte-conductivity sensor, a capacitive field-effect pH sensor and a thin-film Pt-temperature sensor. Due to the multifunctional properties of BST, it is utilized as final outermost coating layer of the processed sensor chip and serves as passivation and protection layer as well as pH-sensitive transducer material at the same time. The results of testing of the individual sensors of the developed multiparameter sensor chip are presented. In addition, a quasi-simultaneous multiparameter characterization of the sensor chip in buffer solutions with different pH value and electrolyte conductivity is performed. To study the sensor behavior and the suitability of BST as multifunctional material under harsh environmental conditions, the sensor chip was exemplarily tested in a biogas digestate.},
  language  = {en}
}
@article{BaeckerKramerHucketal.2014,
  author    = {B{\"a}cker, Matthias and Kramer, F. and Huck, Christina and Poghossian, Arshak and Bratov, A. and Abramova, N. and Sch{\"o}ning, Michael Josef},
  title     = {Planar and 3D interdigitated electrodes for biosensing applications: The impact of a dielectric barrier on the sensor properties},
  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.201330416},
  pages     = {1357 -- 1363},
  year      = {2014},
  abstract  = {Planar and three-dimensional (3D) interdigitated electrodes (IDE) with electrode digits separated by an insulating barrier of different heights were electrochemically characterized and compared in terms of their sensing properties. Due to the impact of the surface resistance, both types of IDE structures display a non-linear behavior in low-ionic strength solutions. The experimental data were fitted to an electrical equivalent circuit and interpreted taking into account the surface-charge-governed properties. The effect of a charged polyelectrolyte layer electrostatically assembled onto the sensor surface on the surface resistance in solutions with different KCl concentration is studied. In case of the same electrode footprint, 3D-IDEs show a larger cell constant and a higher sensitivity to molecular adsorption than that of planar IDEs. The obtained results demonstrate the potential of 3D-IDEs as a new transducer structure for a direct label-free sensing of charged molecules.},
  language  = {en}
}
@article{HuckPoghossianBaeckeretal.2014,
  author    = {Huck, Christina and Poghossian, Arshak and B{\"a}cker, Matthias and Chaudhuri, S. and Zander, W. and Schubert, J. and Begoyan, V. K. and Buniatyan, V. V. and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Capacitively coupled electrolyte-conductivity sensor based on high-k material of barium strontium titanate},
  series = {Sensors and actuators. B: Chemical},
  journal   = {Sensors and actuators. B: Chemical},
  number    = {198},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2014.02.103},
  pages     = {102 -- 109},
  year      = {2014},
  language  = {en}
}
@article{WuBronderPoghossianetal.2014,
  author    = {Wu, Chunsheng and Bronder, Thomas and Poghossian, Arshak and Werner, Frederik and B{\"a}cker, Matthias and Sch{\"o}ning, Michael Josef},
  title     = {Label-free electrical detection of DNA with a multi-spot LAPS: First step towards light-addressable DNA chips},
  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.201330442},
  pages     = {1423 -- 1428},
  year      = {2014},
  abstract  = {A multi-spot (4 × 4 spots) light-addressable potentiometric sensor (MLAPS) consisting of an Al-p-Si-SiO2 structure has been applied for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge for the first time. Single-stranded probe ssDNA molecules (20 bases) were covalently immobilized onto the silanized SiO2 gate surface. The unspecific adsorption of mismatch ssDNA on the MLAPS gate surface was blocked by bovine serum albumin molecules. To reduce the screening effect and to achieve a high sensor signal, the measurements were performed in a low ionic-strength solution. The photocurrent-voltage (I-V) curves were simultaneously recorded on all 16 spots after each surface functionalization step. Large shifts of I-V curves of 25 mV were registered after the DNA immobilization and hybridization event. In contrast, a small potential shift (∼5 mV) was observed in case of mismatch ssDNA, revealing good specificity of the sensor. The obtained results demonstrate the potential of the MLAPS as promising transducer platform for the multi-spot label-free electrical detection of DNA molecules by their intrinsic molecular charge.},
  language  = {en}
}
@article{GuoSekiMiyamotoetal.2014,
  author    = {Guo, Yuanyuan and Seki, Kosuke and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Novel photoexcitation method for light-addressable potentiometric sensor with higher spatial resolution},
  series = {Applied physics express : APEX},
  volume    = {7},
  journal   = {Applied physics express : APEX},
  number    = {6},
  publisher = {IOP},
  address   = {Bristol},
  issn      = {1882-0786 (E-Journa); 1882-0778 (Print)},
  doi       = {10.7567/APEX.7.067301},
  pages     = {067301-4},
  year      = {2014},
  abstract  = {A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) is proposed to achieve a higher spatial resolution of chemical images. The proposed method employs a combined light source that consists of a modulated light probe, which generates the alternating photocurrent signal, and a ring of constant illumination surrounding it. The constant illumination generates a sheath of carriers with increased concentration which suppresses the spread of photocarriers by enhanced recombination. A device simulation was carried out to verify the effect of constant illumination on the spatial resolution, which demonstrated that a higher spatial resolution can be obtained.},
  language  = {en}
}
@article{WagnerDollSchoening2014,
  author    = {Wagner, Patrick and Doll, Theodor and Sch{\"o}ning, Michael Josef},
  title     = {Engineering of functional interfaces / Patrick Wagner ; Theodor Doll ; Michael J. Sch{\"o}ning (eds.)},
  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-Book); 1862-6319 (E-Book); 0031-8965 (Print); 1862-6300 (Print)},
  doi       = {10.1002/pssa.201470241},
  pages     = {1339 -- 1339},
  year      = {2014},
  language  = {en}
}
@article{RiedelKartchemnikSchoeningetal.2014,
  author    = {Riedel, Marc and Kartchemnik, Julia and Sch{\"o}ning, Michael Josef and Lisdat, Fred},
  title     = {Impedimetric DNA detection - steps forward to sensorial application},
  series = {Analytical chemistry},
  volume    = {86 (2014)},
  journal   = {Analytical chemistry},
  number    = {15},
  publisher = {ACS Publications},
  address   = {Columbus},
  issn      = {1520-6882 (E-Journal); 0003-2700 (Print); 0096-4484 (Print)},
  doi       = {10.1021/ac501800q},
  pages     = {7867 -- 7874},
  year      = {2014},
  abstract  = {This study describes a label-free impedimetric sensor based on short ssDNA recognition elements for the detection of hybridization events. We concentrate on the elucidation of the influence of target length and recognition sequence position on the sensorial performance. The impedimetric measurements are performed in the presence of the redox system ferri-/ferrocyanide and show an increase in charge transfer resistance upon hybridization of ssDNA to the sensor surface. Investigations on the impedimetric signal stability demonstrate a clear influence of the buffers used during the sensor preparation and the choice of the passivating mercaptoalcanol compound. A stable sensor system has been developed, enabling a reproducible detection of 25mer target DNA in the low nanomolar range. After hybridization, a sensor regeneration can be reached with deionized water by adjustment of effective convection conditions, ensuring a sensor reusability. By investigations of longer targets with overhangs exposed to the solution, we can demonstrate applicability of the impedimetric detection for longer ssDNA. However, a decreasing charge transfer resistance change (ΔRct) is found by extending the overhang. As a strategy to increase the impedance change for longer target strands, the position of the recognition sequence can be designed in a way that a small overhang is exposed to the electrode surface. This is found to result in an increase in the relative Rct change. These results suggest that DNA and consequently negative charge near the electrode possess a larger impact on the impedimetric signal than DNA further away.},
  language  = {en}
}
@article{GuoMiyamotoWagneretal.2014,
  author    = {Guo, Yuanyuan and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Device simulation of the light-addressable potentiometric sensor for the investigation of the spatial resolution},
  series = {Sensors and actuators B: Chemical},
  volume    = {204},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2014.08.016},
  pages     = {659 -- 665},
  year      = {2014},
  abstract  = {As a semiconductor-based electrochemical sensor, the light-addressable potentiometric sensor (LAPS) can realize two dimensional visualization of (bio-)chemical reactions at the sensor surface addressed by localized illumination. Thanks to this imaging capability, various applications in biochemical and biomedical fields are expected, for which the spatial resolution is critically significant. In this study, therefore, the spatial resolution of the LAPS was investigated in detail based on the device simulation. By calculating the spatiotemporal change of the distributions of electrons and holes inside the semiconductor layer in response to a modulated illumination, the photocurrent response as well as the spatial resolution was obtained as a function of various parameters such as the thickness of the Si substrate, the doping concentration, the wavelength and the intensity of illumination. The simulation results verified that both thinning the semiconductor substrate and increasing the doping concentration could improve the spatial resolution, which were in good agreement with known experimental results and theoretical analysis. More importantly, new findings of interests were also obtained. As for the dependence on the wavelength of illumination, it was found that the known dependence was not always the case. When the Si substrate was thick, a longer wavelength resulted in a higher spatial resolution which was known by experiments. When the Si substrate was thin, however, a longer wavelength of light resulted in a lower spatial resolution. This finding was explained as an effect of raised concentration of carriers, which reduced the thickness of the space charge region. The device simulation was found to be helpful to understand the relationship between the spatial resolution and device parameters, to understand the physics behind it, and to optimize the device structure and measurement conditions for realizing higher performance of chemical imaging systems.},
  language  = {en}
}
@article{KhaydukovaZadorozhnayaKirsanovetal.2014,
  author    = {Khaydukova, M. M. and Zadorozhnaya, O. A. and Kirsanov, D. O. and Iken, Heiko and Rolka, David and Sch{\"o}ning, Michael Josef and Babain, V. A. and Vlasov, Yu. G. and Legin, A. V.},
  title     = {Multivariate processing of atomic-force microscopy images for detection of the response of plasticized polymeric membranes},
  series = {Russian journal of applied chemistry},
  volume    = {87},
  journal   = {Russian journal of applied chemistry},
  number    = {3},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {1608-3296 (E-Journal); 1070-4272 (Print)},
  doi       = {10.1134/S1070427214030112},
  pages     = {307 -- 314},
  year      = {2014},
  abstract  = {The possibility of using the atomic-force microscopy as a method for detection of the analytical signal from plasticized polymeric sensor membranes was analyzed. The surfaces of cadmium-selective membranes based on two polymeric matrices were examined. The digital images were processed with multivariate image analysis techniques. A correlation was found between the surface profile of an ion-selective membrane and the concentration of the ion in solution.},
  language  = {en}
}
@article{BaeckerSchusserPoghossianetal.2014,
  author    = {B{\"a}cker, Matthias and Schusser, Sebastian and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Multi-Parametererfassung mit siliziumbasiertem Sensorchip: Aus Drei mach Eins},
  series = {GIT Labor-Fachzeitschrift},
  journal   = {GIT Labor-Fachzeitschrift},
  number    = {2},
  publisher = {Wiley},
  issn      = {0016-3538},
  pages     = {28 -- 30},
  year      = {2014},
  language  = {de}
}
@article{MuribYeapMartensetal.2014,
  author    = {Murib, Mohammed Sharif and Yeap, Weng-Siang and Martens, Daan and Bienstman, Peter and Ceuninck, Ward de and Grinsven, Bart van and Sch{\"o}ning, Michael Josef and Michiels, Luc and Haenen, Ken and Ameloot, Marcel and Serpeng{\"u}zel, Ali and Wagner, Patrick},
  title     = {Photonic detection and characterization of DNA using sapphire microspheres},
  series = {Journal of biomedical optics},
  volume    = {19},
  journal   = {Journal of biomedical optics},
  number    = {9},
  publisher = {SPIE},
  address   = {Bellingham},
  issn      = {1560-2281 (E-Journal); 1083-3668 (Print)},
  doi       = {10.1117/1.JBO.19.9.097006},
  pages     = {097006},
  year      = {2014},
  abstract  = {A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500  μm, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immobilized on a sapphire microsphere and hybridized with a 29-mer target DNA. Whispering gallery modes (WGMs) were monitored before the sapphire was functionalized with DNA and after it was functionalized with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The shift in WGMs from the surface modification with DNA was measured and correlated well with the estimated thickness of the add-on DNA layer. It is shown that ssDNA is more uniformly oriented on the sapphire surface than dsDNA. In addition, it is shown that functionalization of the sapphire spherical surface with DNA does not affect the quality factor (Q≈104) of the sapphire microspheres. The use of sapphire is especially interesting because this material is chemically resilient, biocompatible, and widely used for medical implants.},
  language  = {en}
}
@article{SiqueiraMolinnusBegingetal.2014,
  author    = {Siqueira, Jose R. and Molinnus, Denise and Beging, Stefan and Sch{\"o}ning, Michael Josef},
  title     = {Incorporating a hybrid urease-carbon nanotubes sensitive nanofilm on capacitive field-effect sensors for urea detection},
  series = {Analytical chemistry},
  volume    = {86},
  journal   = {Analytical chemistry},
  number    = {11},
  publisher = {ACS Publications},
  address   = {Columbus},
  issn      = {1520-6882 (E-Journal); 0003-2700 (Print); 0096-4484 (Print)},
  doi       = {10.1021/ac500458s},
  pages     = {5370 -- 5375},
  year      = {2014},
  abstract  = {The ideal combination among biomolecules and nanomaterials is the key for reaching biosensing units with high sensitivity. The challenge, however, is to find out a stable and sensitive film architecture that can be incorporated on the sensor's surface. In this paper, we report on the benefits of incorporating a layer-by-layer (LbL) nanofilm of polyamidoamine (PAMAM) dendrimer and carbon nanotubes (CNTs) on capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors for detecting urea. Three sensor arrangements were studied in order to investigate the adequate film architecture, involving the LbL film with the enzyme urease: (i) urease immobilized directly onto a bare EIS [EIS-urease] sensor; (ii) urease atop the LbL film over the EIS [EIS-(PAMAM/CNT)-urease] sensor; and (iii) urease sandwiched between the LbL film and another CNT layer [EIS-(PAMAM/CNT)-urease-CNT]. The surface morphology of all three urea-based EIS biosensors was investigated by atomic force microscopy (AFM), while the biosensing abilities were studied by means of capacitance-voltage (C/V) and dynamic constant-capacitance (ConCap) measureaments at urea concentrations ranging from 0.1 mM to 100 mM. The EIS-urease and EIS-(PAMAM/CNT)-urease sensors showed similar sensitivity (∼18 mV/decade) and a nonregular signal behavior as the urea concentration increased. On the other hand, the EIS-(PAMAM/CNT)-urease-CNT sensor exhibited a superior output signal performance and higher sensitivity of about 33 mV/decade. The presence of the additional CNT layer was decisive to achieve a urea based EIS sensor with enhanced properties. Such sensitive architecture demonstrates that the incorporation of an adequate hybrid enzyme-nanofilm as sensing unit opens new prospects for biosensing applications using the field-effect sensor platform.},
  language  = {en}
}
@article{GuoSekiMiyamotoetal.2014,
  author    = {Guo, Yuanyuan and Seki, Kosuke and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Device simulation of the light-addressable potentiometric sensor with a novel photoexcitation method for a higher spatial resolution},
  series = {Procedia Engineering},
  volume    = {87},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2014.11.369},
  pages     = {456 -- 459},
  year      = {2014},
  abstract  = {A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) realized a higher spatial resolution of chemical imaging. In this method, a modulated light probe, which generates the alternating photocurrent signal, is surrounded by a ring of constant light, which suppresses the lateral diffusion of photocarriers by enhancing recombination. A device simulation verified that a higher spatial resolution could be obtained by adjusting the gap between the modulated and constant light. It was also found that a higher intensity and a longer wavelength of constant light was more effective. However, there exists a tradeoff between the spatial resolution and the amplitude of the photocurrent, and thus, the signal-to-noise ratio. A tilted incidence of constant light was applied, which could achieve even higher resolution with a smaller loss of photocurrent.},
  language  = {en}
}
@article{MiyamotoSekiWagneretal.2014,
  author    = {Miyamoto, K. and Seki, K. and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, T.},
  title     = {Enhancement of the spatial resolution of the chemical imaging sensor by a hybrid fiber-optic illumination},
  series = {Procedia Engineering},
  volume    = {87},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2014.11.563},
  pages     = {612 -- 615},
  year      = {2014},
  abstract  = {The chemical imaging sensor, which is based on the principle of the light-addressable potentiometric sensor (LAPS), is a powerful tool to visualize the spatial distribution of chemical species on the sensor surface. The spatial resolution of this sensor depends on the diffusion of photocarriers excited by a modulated light. In this study, a novel hybrid fiber-optic illumination was developed to enhance the spatial resolution. It consists of a modulated light probe to generate a photocurrent signal and a ring of constant light, which suppresses the lateral diffusion of minority carriers excited by the modulated light. It is demonstrated that the spatial resolution was improved from 92 μm to 68 μm.},
  language  = {en}
}
@article{BronderWuPoghossianetal.2014,
  author    = {Bronder, Thomas and Wu, Chunsheng and Poghossian, Arshak and Werner, Frederik and Keusgen, M. and Sch{\"o}ning, Michael Josef},
  title     = {Label-free detection of DNA hybridization with light-addressable potentiometric sensors: comparison of various DNA-immobilization strategies},
  series = {Procedia Engineering},
  volume    = {87},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2014.11.647},
  pages     = {755 -- 758},
  year      = {2014},
  abstract  = {Light-addressable potentiometric sensors (LAPS) consisting of a p-Si-SiO2 and p-Si-SiO2-Au structure, respectively, have been tested for a label-free electrical detection of DNA (deoxyribonucleic acid) hybridization. Three different strategies for immobilizing single-stranded probe DNA (ssDNA) molecules on a LAPS surface have been studied and compared: (a) immobilization of thiol-modified ssDNA on the patterned Au surface via gold-thiol bond, (b) covalent immobilization of amino-modified ssDNA onto the SiO2 surface functionalized with 3-aminopropyltriethoxysilane and (c) layer-by-layer adsorption of negatively charged ssDNA on a positively charged weak polyelectrolyte layer of poly(allylamine hydrochloride).},
  language  = {en}
}
@article{HuckPoghossianBaeckeretal.2014,
  author    = {Huck, Christina and Poghossian, Arshak and B{\"a}cker, Matthias and Reisert, Steffen and Schubert, J. and Zander, W. and Begoyan, V. K. and Buniatyan, V. V. and Sch{\"o}ning, Michael Josef},
  title     = {Chemical sensors based on a high-k perovskite oxide of barium strontium titanate},
  series = {Procedia Engineering},
  volume    = {87},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2014.11.258},
  pages     = {28 -- 31},
  year      = {2014},
  abstract  = {High-k perovskite oxide of barium strontium titanate (BST) represents a very attractive multi-functional transducer material for the development of (bio-)chemical sensors for liquids. In this work, BST films have been applied as a sensitive transducer material for a label-free detection of adsorbed charged macromolecules (positively charged polyelectrolytes) and concentration of hydrogen peroxide vapor as well as protection insulator layer for a contactless electrolyte-conductivity sensor. The experimental results of characterization of individual sensors are presented. Special emphasis is devoted towards the development of a capacitively-coupled contactless electrolyte-conductivity sensor.},
  language  = {en}
}
@article{SchusserBaeckerKrischeretal.2014,
  author    = {Schusser, Sebastian and B{\"a}cker, Matthias and Krischer, M. and Wenzel, L. and Leinhos, Marcel and Poghossian, Arshak and Biselli, Manfred and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Enzymatically catalyzed degradation of biodegradable polymers investigated by means of a semiconductor-based field-effect sensor},
  series = {Procedia Engineering},
  volume    = {87},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2014.11.689},
  pages     = {1314 -- 1317},
  year      = {2014},
  abstract  = {A semiconductor field-effect device has been used for an enzymatically catalyzed degradation of biopolymers for the first time. This novel technique is capable to monitor the degradation process of multiple samples in situ and in real-time. As model system, the degradation of the biopolymer poly(D, L-lactic acid) has been monitored in the degradation medium containing the enzyme lipase from Rhizomucor miehei. The obtained results demonstrate the potential of capacitive field-effect sensors for degradation studies of biodegradable polymers.},
  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{ReisertGeisslerWeileretal.2015,
  author    = {Reisert, Steffen and Geissler, H. and Weiler, C. and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Multiple sensor-type system for monitoring the microbicidal effectiveness of aseptic sterilisation processes},
  series = {Food control},
  volume    = {47},
  journal   = {Food control},
  issn      = {1873-7129 (E-Journal); 0956-7135 (Print)},
  doi       = {10.1016/j.foodcont.2014.07.063},
  pages     = {615 -- 622},
  year      = {2015},
  abstract  = {The present work describes a novel multiple sensor-type system for the real-time analysis of aseptic sterilisation processes employing gaseous hydrogen peroxide (H2O2) as a sterilant. The inactivation kinetics of Bacillus atrophaeus by gaseous H2O2 have been investigated by means of a methodical calibration experiment, taking into account the process variables H2O2 concentration, humidity and gas temperature. It has been found that the microbicidal effectiveness at H2O2 concentrations above 2\% v/v is largely determined by the concentration itself, while at lower H2O2 concentrations, the gas temperature and humidity play a leading role. Furthermore, the responses of different types of gas sensors towards the influencing factors of the sterilisation process have been analysed within the same experiment. Based on a correlation established between the inactivation kinetics and the sensor responses, a calorimetric H2O2 sensor and a metal-oxide semiconductor (MOX) sensor have been identified as possible candidates for monitoring the microbicidal effectiveness of aseptic sterilisation processes employing gaseous H2O2. Therefore, two linear models that describe the relationship between sensor response and microbicidal effectiveness have been proposed.},
  language  = {en}
}
@article{YoshinobuMiyamotoWagneretal.2015,
  author    = {Yoshinobu, Tatsuo and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Recent developments of chemical imaging sensor systems based on the principle of the light-addressable potentiometric sensor},
  series = {Sensors and actuators B: Chemical},
  volume    = {207, Part B},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2014.09.002},
  pages     = {926 -- 932},
  year      = {2015},
  abstract  = {The light-addressable potentiometric sensor (LAPS) is an electrochemical sensor with a field-effect structure to detect the variation of the Nernst potential at its sensor surface, the measured area on which is defined by illumination. Thanks to this light-addressability, the LAPS can be applied to chemical imaging sensor systems, which can visualize the two-dimensional distribution of a particular target ion on the sensor surface. Chemical imaging sensor systems are expected to be useful for analysis of reaction and diffusion in various electrochemical and biological samples. Recent developments of LAPS-based chemical imaging sensor systems, in terms of the spatial resolution, measurement speed, image quality, miniaturization and integration with microfluidic devices, are summarized and discussed.},
  language  = {en}
}
@article{PoghossianBaeckerMayeretal.2015,
  author    = {Poghossian, Arshak and B{\"a}cker, Matthias and Mayer, Dirk and Sch{\"o}ning, Michael Josef},
  title     = {Gating capacitive field-effect sensors by the charge of nanoparticle/molecule hybrids},
  series = {Nanoscale},
  journal   = {Nanoscale},
  publisher = {Royal Society of Chemistry (RSC)},
  address   = {Cambridge},
  issn      = {2040-3372 (E-Journal); 2040-3364 (Print)},
  doi       = {10.1039/C4NR05987E},
  pages     = {1023 -- 1031},
  year      = {2015},
  language  = {en}
}
@article{SchusserPoghossianBaeckeretal.2015,
  author    = {Schusser, Sebastian and Poghossian, Arshak and B{\"a}cker, Matthias and Krischer, M. and Leinhos, Marcel and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {An application of field-effect sensors for in-situ monitoring of degradation of biopolymers},
  series = {Sensors and actuators B: Chemical},
  volume    = {207, Part B},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2014.10.058},
  pages     = {954 -- 959},
  year      = {2015},
  abstract  = {The characterization of the degradation kinetics of biodegradable polymers is mandatory with regard to their proper application. In the present work, polymer-modified electrolyte-insulator-semiconductor (PMEIS) field-effect sensors have been applied for in-situ monitoring of the pH-dependent degradation kinetics of the commercially available biopolymer poly(d,l-lactic acid) (PDLLA) in buffer solutions from pH 3 to pH 13. PDLLA films of 500 nm thickness were deposited on the surface of an Al-p-Si-SiO2-Ta2O5 structure from a polymer solution by means of spin-coating method. The PMEIS sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by degradation processes. A faster degradation has been observed for PDLLA films exposed to alkaline solutions (pH 9, pH 11 and pH 13).},
  language  = {en}
}
@article{MuribYeapMartensetal.2015,
  author    = {Murib, M. S. and Yeap, W. S. and Martens, D. and Liu, X. and Bienstman, P. and Fahlman, M. and Sch{\"o}ning, Michael Josef and Michiels, L. and Haenen, K. and Serpeng{\"u}zel, A. and Wagner, Patrick},
  title     = {Photonic studies on polymer-coated sapphire-spheres : a model system for biological ligands},
  series = {Sensors and actuators A: Physical},
  volume    = {222},
  journal   = {Sensors and actuators A: Physical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3069 (E-Journal); 0924-4247 (Print)},
  doi       = {10.1016/j.sna.2014.11.024},
  pages     = {212 -- 219},
  year      = {2015},
  abstract  = {In this study we show an optical biosensor concept, based on elastic light scattering from sapphire microspheres. Transmitted and elastic scattering intensity of the microspheres (radius 500 μm, refractive index 1.77) on an optical fiber half coupler is analyzed at 1510 nm. The 0.43 nm angular mode spacing of the resonances is comparable to the angular mode spacing value estimated using the optical size of the microsphere. The spectral linewidths of the resonances are in the order of 0.01 nm, which corresponds to quality factors of approximately 105. A polydopamine layer is used as a functionalizing agent on sapphire microspherical resonators in view of biosensor implementation. The varying layer thickness on the microsphere is determined as a function of the resonance wavelength shift. It is shown that polymer functionalization has a minor effect on the quality factor. This is a promising step toward the development of an optical biosensor.},
  language  = {en}
}
@article{WuBronderPoghossianetal.2015,
  author    = {Wu, Chunsheng and Bronder, Thomas and Poghossian, Arshak and Werner, Frederik and Sch{\"o}ning, Michael Josef},
  title     = {Label-free detection of DNA using light-addressable potentiometric sensor modified with a positively charged polyelectrolyte layer},
  series = {Nanoscale},
  volume    = {14},
  journal   = {Nanoscale},
  number    = {7},
  publisher = {Royal Society of Chemistry (RSC)},
  address   = {Cambridge},
  doi       = {10.1039/C4NR07225A},
  pages     = {6143 -- 6150},
  year      = {2015},
  abstract  = {A multi-spot (16 spots) light-addressable potentiometric sensor (MLAPS) consisting of an Al-p-Si-SiO2 structure modified with a weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was applied for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge for the first time. To achieve a preferentially flat orientation of DNA strands and thus, to reduce the distance between the DNA charge and MLAPS surface, the negatively charged probe single-stranded DNAs (ssDNA) were electrostatically adsorbed onto the positively charged PAH layer using a simple layer-by-layer (LbL) technique. In this way, more DNA charge can be positioned within the Debye length, yielding a higher sensor signal. The surface potential changes in each spot induced due to the surface modification steps (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), non-specific adsorption of mismatched ssDNA) were determined from the shifts of photocurrent-voltage curves along the voltage axis. A high sensor signal of 83 mV was registered after immobilization of probe ssDNA onto the PAH layer. The hybridization signal increases from 5 mV to 32 mV with increasing the concentration of cDNA from 0.1 nM to 5 μM. In contrast, a small signal of 5 mV was recorded in the case of non-specific adsorption of fully mismatched ssDNA (5 μM). The obtained results demonstrate the potential of the MLAPS in combination with the simple and rapid LbL immobilization technique as a promising platform for the future development of multi-spot light-addressable label-free DNA chips with direct electrical readout.},
  language  = {en}
}
@article{BegingLeinhosJablonskietal.2015,
  author    = {Beging, Stefan and Leinhos, Marcel and Jablonski, Melanie and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Studying the spatially resolved immobilisation of enzymes on a capacitive field-effect structure by means of nano-spotting},
  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.201431891},
  pages     = {1353 -- 1358},
  year      = {2015},
  language  = {en}
}
@article{PoghossianKatzSchoening2015,
  author    = {Poghossian, Arshak and Katz, Evgeny and Sch{\"o}ning, Michael Josef},
  title     = {Enzyme logic AND-Reset and OR-Reset gates based on a field-effect electronic transducer modified with multi-enzyme membrane},
  series = {Chemical Communications},
  volume    = {51},
  journal   = {Chemical Communications},
  publisher = {Royal Society of Chemistry (RSC)},
  address   = {Cambridge},
  doi       = {10.1039/C5CC01362C},
  pages     = {6564 -- 6567},
  year      = {2015},
  abstract  = {Capacitive field-effect sensors modified with a multi-enzyme membrane have been applied for an electronic transduction of biochemical signals processed by enzyme-based AND-Reset and OR-Reset logic gates. The local pH change at the sensor surface induced by the enzymatic reaction was used for the activation of the Reset function for the first time.},
  language  = {en}
}
@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{HuckPoghossianBaeckeretal.2015,
  author    = {Huck, Christina and Poghossian, Arshak and B{\"a}cker, Matthias and Reisert, Steffen and Kramer, Friederike and Begoyan, Vardges K. and Buniatyan, Vahe V. and Sch{\"o}ning, Michael Josef},
  title     = {Multi-parameter sensing using high-k oxide of barium strontium titanate},
  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.201431911},
  pages     = {1259},
  year      = {2015},
  abstract  = {High-k perovskite oxide of barium strontium titanate (BST) represents a very attractive multi-functional transducer material for the development of (bio-)chemical sensors. In this work, a Si-based sensor chip containing Pt interdigitated electrodes covered with a thin BST layer (485 nm) has been developed for multi-parameter chemical sensing. The chip has been applied for the contactless measurement of the electrolyte conductivity, the detection of adsorbed charged macromolecules (positively charged polyelectrolytes of polyethylenimine) and the concentration of hydrogen peroxide (H2O2) vapor. The experimental results of functional testing of individual sensors are presented. The mechanism of the BST sensitivity to charged polyelectrolytes and H2O2 vapor has been proposed and discussed.},
  language  = {en}
}
@article{JildehWagnerSchoeningetal.2015,
  author    = {Jildeh, Zaid B. and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Pieper, Martin},
  title     = {Simulating the electromagnetic-thermal treatment of thin aluminium layers for adhesion improvement},
  series = {Physica status solidi (a)},
  volume    = {Vol. 212},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201431893},
  pages     = {1234 -- 1241},
  year      = {2015},
  abstract  = {A composite layer material used in packaging industry is made from joining layers of different materials using an adhesive. An important processing step in the production of aluminium-containing composites is the surface treatment and consequent coating of adhesive material on the aluminium surface. To increase adhesion strength between aluminium layer and the adhesive material, the foil is heat treated. For efficient heating, induction heating was considered as state-of-the-art treatment process. Due to the complexity of the heating process and the unpredictable nature of the heating source, the control of the process is not yet optimised. In this work, a finite element analysis of the process was established and various process parameters were studied. The process was simplified and modelled in 3D. The numerical model contains an air domain, an aluminium layer and a copper coil fitted with a magnetic field concentrating material. The effect of changing the speed of the aluminium foil (or rolling speed) was studied with the change of the coil current. Statistical analysis was used for generating a general control equation of coil current with changing rolling speed.},
  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{BreuerRaueKirschbaumetal.2015,
  author    = {Breuer, Lars and Raue, Markus and Kirschbaum, M. and Mang, Thomas and Sch{\"o}ning, Michael Josef and Thoelen, R. and Wagner, Torsten},
  title     = {Light-controllable polymeric material based on temperature-sensitive hydrogels with incorporated graphene oxide},
  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.201431944},
  pages     = {1368 -- 1374},
  year      = {2015},
  abstract  = {Poly(N-isopropylacrylamide) (PNIPAAm) hydrogel films with incorporated graphene oxide (GO) were developed and tested as light-stimulated actuators. GO dispersions were synthesized via Hummers method and characterized toward their optical properties and photothermal energy conversion. The hydrogels were prepared by means of photopolymerization. In addition, the influence of GO within the hydrogel network on the lower critical solution temperature (LCST) was investigated by differential scanning calorimetry (DSC). The optical absorbance and the response to illumination were determined as a function of GO concentration for thin hydrogel films. A proof of principle for the stimulation with light was performed.},
  language  = {en}
}
@article{DantismTakenagaWagneretal.2015,
  author    = {Dantism, S. and Takenaga, S. and Wagner, P. and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Light-addressable Potentiometric Sensor (LAPS) Combined with Multi-chamber Structures to Investigate the Metabolic Activity of Cells},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.647},
  pages     = {384 -- 387},
  year      = {2015},
  abstract  = {LAPS are field-effect-based potentiometric sensors which are able to monitor analyte concentrations in a spatially resolved manner. Hence, a LAPS sensor system is a powerful device to record chemical imaging of the concentration of chemical species in an aqueous solution, chemical reactions, or the growth of cell colonies on the sensor surface, to record chemical images. In this work, multi-chamber 3D-printed structures made out of polymer (PP-ABS) were combined with LAPS chips to analyse differentially and simultaneously the metabolic activity of Escherichia coli K12 and Chinese hamster ovary (CHO) cells, and the responds of those cells to the addition of glucose solution.},
  language  = {en}
}
@article{MolinnusBaeckerSiegertetal.2015,
  author    = {Molinnus, Denise and B{\"a}cker, Matthias and Siegert, Petra and Willenberg, H. and Poghossian, Arshak and Keusgen, M. and Sch{\"o}ning, Michael Josef},
  title     = {Detection of Adrenaline Based on Substrate Recycling Amplification},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.708},
  pages     = {540 -- 543},
  year      = {2015},
  abstract  = {An amperometric enzyme biosensor has been applied for the detection of adrenaline. The adrenaline biosensor has been prepared by modification of an oxygen electrode with the enzyme laccase that operates at a broad pH range between pH 3.5 to pH 8. The enzyme molecules were immobilized via cross-linking with glutaraldehyde. The sensitivity of the developed adrenaline biosensor in different pH buffer solutions has been studied.},
  language  = {en}
}
@article{SchusserKrischerMolinetal.2015,
  author    = {Schusser, Sebastian and Krischer, M. and Molin, D. G. M. and Akker, N. M. S. van den and B{\"a}cker, Matthias and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Sensor System for in-situ and Real-time Monitoring of Polymer (bio) degradation},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.815},
  pages     = {948 -- 951},
  year      = {2015},
  abstract  = {A sensor system for investigating (bio)degradationprocesses of polymers is presented. The system utilizes semiconductor field-effect sensors and is capable of monitoring the degradation process in-situ and in real-time. The degradation of the polymer poly(d,l-lactic acid) is exemplarily monitored in solutions with different pH value, pH-buffer solution containing the model enzyme lipase from Rhizomucormiehei and cell-culture medium containing supernatants from stimulated and non-stimulated THP-1-derived macrophages mimicking activation of the immune system.},
  language  = {en}
}
@article{PilasMarianoKeusgenetal.2015,
  author    = {Pilas, Johanna and Mariano, K. and Keusgen, M. and Selmer, Thorsten and Sch{\"o}ning, Michael Josef},
  title     = {Optimization of an Enzyme-based Multi-parameter Biosensor for Monitoring Biogas Processes},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.702},
  pages     = {532 -- 535},
  year      = {2015},
  language  = {en}
}
@article{MiyamotoBingWagneretal.2015,
  author    = {Miyamoto, Ko-ichiro and Bing, Yu and Wagner, Torsten and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef},
  title     = {Visualization of Defects on a Cultured Cell Layer by Utilizing Chemical Imaging Sensor},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.806},
  pages     = {936 -- 939},
  year      = {2015},
  abstract  = {The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) inthe sample. In this study, a novel wound-healing assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the defect of a cell layer brought into proximity of the sensing surface.A reduced impedance inside the defect, which was artificially formed ina cell layer, was successfully visualized in a photocurrent image.},
  language  = {en}
}
@article{BronderPoghossianSchejaetal.2015,
  author    = {Bronder, Thomas and Poghossian, Arshak and Scheja, S. and Wu, Chunsheng and Keusgen, M. and Sch{\"o}ning, Michael Josef},
  title     = {Electrostatic Detection of Unlabelled Single- and Double-stranded DNA Using Capacitive Field-effect Devices Functionalized with a Positively Charged Polyelectrolyte Layer},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.710},
  pages     = {544 -- 547},
  year      = {2015},
  abstract  = {Capacitive field-effect electrolyte-insulator-semiconductor sensors consisting of an Al-p-Si-SiO2 structure have been used for the electrical detection of unlabelled single- and double-stranded DNA (dsDNA) molecules by their intrinsic charge. A simple functionalization protocol based on the layer-by-layer (LbL) technique was used to prepare a weak polyelectrolyte/probe-DNA bilayer, followed by the hybridization with complementary target DNA molecules. Due to the flat orientation of the LbL-adsorbed DNA molecules, a high sensor signal has been achieved. In addition, direct label-free detection of in-solution hybridized dsDNA molecules has been studied.},
  language  = {en}
}
@article{TakenagaSchneiderErbayetal.2015,
  author    = {Takenaga, Shoko and Schneider, Benno and Erbay, E. and Biselli, Manfred and Schnitzler, Thomas and Sch{\"o}ning, Michael Josef and Wagner, Torsten},
  title     = {Fabrication of biocompatible lab-on-chip devices for biomedical applications by means of a 3D-printing process},
  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.201532053},
  pages     = {1347 -- 1352},
  year      = {2015},
  abstract  = {A new microfluidic assembly method for semiconductor-based biosensors using 3D-printing technologies was proposed for a rapid and cost-efficient design of new sensor systems. The microfluidic unit is designed and printed by a 3D-printer in just a few hours and assembled on a light-addressable potentiometric sensor (LAPS) chip using a photo resin. The cell growth curves obtained from culturing cells within microfluidics-based LAPS systems were compared with cell growth curves in cell culture flasks to examine biocompatibility of the 3D-printed chips. Furthermore, an optimal cell culturing within microfluidics-based LAPS chips was achieved by adjusting the fetal calf serum concentrations of the cell culture medium, an important factor for the cell proliferation.},
  language  = {en}
}
@article{MolinnusBaeckerIkenetal.2015,
  author    = {Molinnus, Denise and B{\"a}cker, Matthias and Iken, Heiko and Poghossian, Arshak and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Concept for a biomolecular logic chip with an integrated sensor and actuator function},
  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.201431913},
  pages     = {1382 -- 1388},
  year      = {2015},
  abstract  = {A concept for a new generation of an integrated multi-functional biosensor/actuator system is developed, which is based on biomolecular logic principles. Such a system is expected to be able to detect multiple biochemical input signals simultaneously and in real-time and convert them into electrical output signals with logical operations such as OR, AND, etc. The system can be designed as a closed-loop drug release device triggered by an enzyme logic gate, while the release of the drug induced by the actuator at the required dosage and timing will be controlled by an additional drug sensor. Thus, the system could help to make an accurate and specific diagnosis. The presented concept is exemplarily demonstrated by using an enzyme logic gate based on a glucose/glucose oxidase system, a temperature-responsive hydrogel mimicking the actuator function and an insulin (drug) sensor. In this work, the results of functional testing of individual amperometric glucose and insulin sensors as well as an impedimetric sensor for the detection of the hydrogel swelling/shrinking are presented.},
  language  = {en}
}
@article{WarmerWagnerSchoeningetal.2015,
  author    = {Warmer, Johannes and Wagner, Patrick and Sch{\"o}ning, Michael Josef and Kaul, Peter},
  title     = {Detection of triacetone triperoxide using temperature cycled metal-oxide semiconductor gas sensors},
  series = {Physica status solidi (a)},
  volume    = {212},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201431882},
  pages     = {1289 -- 1298},
  year      = {2015},
  language  = {en}
}
@article{DelleHuckBaeckeretal.2015,
  author    = {Delle, Lotta E. and Huck, Christina and B{\"a}cker, Matthias and M{\"u}ller, Frank and Grandthyll, Samuel and Jacobs, Karin and Lilischkis, Rainer and Vu, Xuan T. and Sch{\"o}ning, Michael Josef and Wagner, Patrick and Thoelen, Roland and Weil, Maryam and Ingebrandt, Sven},
  title     = {Impedimetric immunosensor for the detection of histamine based on reduced graphene oxide},
  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.201431863},
  pages     = {1327 -- 1334},
  year      = {2015},
  language  = {en}
}
@article{BronderPoghossianSchejaetal.2015,
  author    = {Bronder, Thomas and Poghossian, Arshak and Scheja, Sabrina and Wu, Chunsheng and Keusgen, Michael and Mewes, Dieter and Sch{\"o}ning, Michael Josef},
  title     = {DNA Immobilization and Hybridization Detection by the Intrinsic Molecular Charge Using Capacitive Field-Effect Sensors Modified with a Charged Weak Polyelectrolyte Layer},
  series = {Applied Materials \& Interfaces},
  volume    = {36},
  journal   = {Applied Materials \& Interfaces},
  number    = {7},
  publisher = {American Chemical Society},
  address   = {Washington, DC},
  doi       = {10.1021/acsami.5b05146},
  pages     = {20068 -- 20075},
  year      = {2015},
  abstract  = {Miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge favor the semiconductor field-effect platform as one of the most attractive approaches for the development of label-free DNA chips. In this work, a capacitive field-effect EIS (electrolyte-insulator-semiconductor) sensor covered with a layer-by-layer prepared, positively charged weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was used for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization. The negatively charged probe single-stranded DNA (ssDNA) molecules were electrostatically adsorbed onto the positively charged PAH layer, resulting in a preferentially flat orientation of the ssDNA molecules within the Debye length, thus yielding a reduced charge-screening effect and a higher sensor signal. Each sensor-surface modification step (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), reducing an unspecific adsorption by a blocking agent, incubation with noncomplementary DNA (ncDNA) solution) was monitored by means of capacitance-voltage and constant-capacitance measurements. In addition, the surface morphology of the PAH layer was studied by atomic force microscopy and contact-angle measurements. High hybridization signals of 34 and 43 mV were recorded in low-ionic strength solutions of 10 and 1 mM, respectively. In contrast, a small signal of 4 mV was recorded in the case of unspecific adsorption of fully mismatched ncDNA. The density of probe ssDNA and dsDNA molecules as well as the hybridization efficiency was estimated using the experimentally measured DNA immobilization and hybridization signals and a simplified double-layer capacitor model. The results of field-effect experiments were supported by fluorescence measurements, verifying the DNA-immobilization and hybridization event.},
  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{SchusserKrischerBaeckeretal.2015,
  author    = {Schusser, Sebastian and Krischer, Maximillian and B{\"a}cker, Matthias and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Monitoring of the Enzymatically Catalyzed Degradation of Biodegradable Polymers by Means of Capacitive Field-Effect Sensors},
  series = {Analytical Chemistry},
  volume    = {87},
  journal   = {Analytical Chemistry},
  number    = {13},
  publisher = {ACS Publications},
  address   = {Washington, DC},
  issn      = {1520-6882},
  doi       = {10.1021/acs.analchem.5b00617},
  pages     = {6607 -- 6613},
  year      = {2015},
  abstract  = {Designing novel or optimizing existing biodegradable polymers for biomedical applications requires numerous tests on the effect of substances on the degradation process. In the present work, polymer-modified electrolyte-insulator-semiconductor (PMEIS) sensors have been applied for monitoring an enzymatically catalyzed degradation of polymers for the first time. The thin films of biodegradable polymer poly(d,l-lactic acid) and enzyme lipase were used as a model system. During degradation, the sensors were read-out by means of impedance spectroscopy. In order to interpret the data obtained from impedance measurements, an electrical equivalent circuit model was developed. In addition, morphological investigations of the polymer surface have been performed by means of in situ atomic force microscopy. The sensor signal change, which reflects the progress of degradation, indicates an accelerated degradation in the presence of the enzyme compared to hydrolysis in neutral pH buffer media. The degradation rate increases with increasing enzyme concentration. The obtained results demonstrate the potential of PMEIS sensors as a very promising tool for in situ and real-time monitoring of degradation of polymers.},
  language  = {en}
}
@article{MiyamatoSakakitaWagneretal.2015,
  author    = {Miyamato, Ko-ichiro and Sakakita, Sakura and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Application of chemical imaging sensor to in-situ pH imaging in the vicinity of a corroding metal surface},
  series = {Electrochimica Acta},
  volume    = {183},
  journal   = {Electrochimica Acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0013-4686},
  doi       = {10.1016/j.electacta.2015.07.184},
  pages     = {137 -- 142},
  year      = {2015},
  abstract  = {The chemical imaging sensor was applied to in-situ pH imaging of the solution in the vicinity of a corroding surface of stainless steel under potentiostatic polarization. A test piece of polished stainless steel was placed on the sensing surface leaving a narrow gap filled with artificial seawater and the stainless steel was corroded under polarization. The pH images obtained during polarization showed correspondence between the region of lower pH and the site of corrosion. It was also found that the pH value in the gap became as low as 2 by polarization, which triggered corrosion.},
  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}
}
@article{MuribYeapEurlingsetal.2016,
  author    = {Murib, M. S. and Yeap, W. S. and Eurlings, Y. and Grinsven, B. van and Boyen, H.-G. and Conings, B. and Michiels, L. and Ameloot, M. and Carleer, R. and Warmer, J. and Kaul, P. and Haenen, K. and Sch{\"o}ning, Michael Josef and Ceuninck, W. de and Wagner, P.},
  title     = {Heat-transfer based characterization of DNA on synthetic sapphire chips},
  series = {Sensors and Actuators B: Chemical},
  volume    = {230},
  journal   = {Sensors and Actuators B: Chemical},
  number    = {230},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2016.02.027},
  pages     = {260 -- 271},
  year      = {2016},
  abstract  = {In this study, we show that synthetic sapphire (Al₂O₃), an established implant material, can also serve as a platform material for biosensors comparable to nanocrystalline diamond. Sapphire chips, beads, and powder were first modified with (3-aminopropyl) triethoxysilane (APTES), followed by succinic anhydride (SA), and finally single-stranded probe DNA was EDC coupled to the functionalized layer. The presence of the APTES-SA layer on sapphire powders was confirmed by thermogravimetric analyis and Fourier-transform infrared spectroscopy. Using planar sapphire chips as substrates and X-ray photoelectron spectroscopy (XPS) as surface-sensitive tool, the sequence of individual layers was analyzed with respect to their chemical state, enabling the quantification of areal densities of the involved molecular units. Fluorescence microscopy was used to demonstrate the hybridization of fluorescently tagged target DNA to the probe DNA, including denaturation- and re-hybridization experiments. Due to its high thermal conductivity, synthetic sapphire is especially suitable as a chip material for the heat-transfer method, which was employed to distinguish complementary- and non-complementary DNA duplexes containing single-nucleotide polymorphisms. These results indicate that it is possible to detect mutations electronically with a chemically resilient and electrically insulating chip material.},
  language  = {en}
}
@article{HamadBilattoAdlyetal.2016,
  author    = {Hamad, E. M. and Bilatto, S. E. R. and Adly, N. Y. and Correa, D. S. and Wolfrum, B. and Sch{\"o}ning, Michael Josef and Offenh{\"a}usser, A. and Yakushenko, A.},
  title     = {Inkjet printing of UV-curable adhesive and dielectric inks for microfluidic devices},
  series = {Lab on a Chip},
  volume    = {16},
  journal   = {Lab on a Chip},
  number    = {1},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1473-0189},
  doi       = {10.1039/C5LC01195G},
  pages     = {70 -- 74},
  year      = {2016},
  abstract  = {Bonding of polymer-based microfluidics to polymer substrates still poses a challenge for Lab-On-a-Chip applications. Especially, when sensing elements are incorporated, patterned deposition of adhesives with curing at ambient conditions is required. Here, we demonstrate a fabrication method for fully printed microfluidic systems with sensing elements using inkjet and stereolithographic 3D-printing.},
  language  = {en}
}
@article{MiyamotoYuIsodaetal.2016,
  author    = {Miyamoto, Ko-ichiro and Yu, Bing and Isoda, Hiroko and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Visualization of the recovery process of defects in a cultured cell layer by chemical imaging sensor},
  series = {Sensors and Actuators B: Chemical},
  volume    = {236},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2016.04.018},
  pages     = {965 -- 969},
  year      = {2016},
  abstract  = {The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) in the sample. In this study, a novel cell assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the recovery of defects in a cell layer brought into proximity of the sensing surface. A reduced impedance at a defect formed artificially in a cell layer was successfully visualized in a photocurrent image. The cell layer was cultured over two weeks, during which the temporal change of the photocurrent distribution corresponding to the recovery of the defect was observed.},
  language  = {de}
}
@article{DantismTakenagaWagneretal.2016,
  author    = {Dantism, Shahriar and Takenaga, Shoko and Wagner, Patrick and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Determination of the extracellular acidification of Escherichia coli K12 with a multi-​chamber-​based LAPS system},
  series = {Physica status solidi (a)},
  volume    = {213},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6300},
  doi       = {10.1002/pssa.201533043},
  pages     = {1479 -- 1485},
  year      = {2016},
  abstract  = {On-line monitoring of the metabolic activity of microorganisms involved in intermediate stages of biogas production plays an important role to avoid undesirable "down times" during the biogas production. In order to control this process, an on-chip differential measuring system based on the light-addressable potentiometric sensor (LAPS) principle combined with a 3D-printed multi-chamber structure has been realized. As a test microorganism, Escherichia coli K12 (E. coli K12) were used for cell-based measurements. Multi-chamber structures were developed to determine the metabolic activity of E. coli K12 in suspension for a different number of cells, responding to the addition of a constant or variable amount of glucose concentrations, enabling differential and simultaneous measurements.},
  language  = {en}
}
@article{BreuerRaueStrobeletal.2016,
  author    = {Breuer, Lars and Raue, Markus and Strobel, M. and Mang, Thomas and Sch{\"o}ning, Michael Josef and Thoelen, R. and Wagner, Torsten},
  title     = {Hydrogels with incorporated graphene oxide as light-addressable actuator materials for cell culture environments in lab-on-chip systems},
  series = {Physica status solidi (a)},
  volume    = {213},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6300},
  doi       = {10.1002/pssa.201533056},
  pages     = {1520 -- 1525},
  year      = {2016},
  abstract  = {Abstractauthoren Graphene oxide (GO) nanoparticles were incorporated in temperature-sensitive Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels. The nanoparticles increase the light absorption and convert light energy into heat efficiently. Thus, the hydrogels with GO can be stimulated spatially resolved by illumination as it was demonstrated by IR thermography. The temporal progression of the temperature maximum was detected for different concentrations of GO within the polymer network. Furthermore, the compatibility of PNIPAAm hydrogels with GO and cell cultures was investigated. For this purpose, culture medium was incubated with hydrogels containing GO and the viability and morphology of chinese hamster ovary (CHO) cells was examined after several days of culturing in presence of this medium.},
  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{WuPoghossianBronderetal.2016,
  author    = {Wu, Chunsheng and Poghossian, Arshak and Bronder, Thomas and Sch{\"o}ning, Michael Josef},
  title     = {Sensing of double-stranded DNA molecules by their intrinsic molecular charge using the light-addressable potentiometric sensor},
  series = {Sensors and Actuators B: Chemical},
  journal   = {Sensors and Actuators B: Chemical},
  number    = {229},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2016.02.004},
  pages     = {506 -- 512},
  year      = {2016},
  abstract  = {A multi-spot light-addressable potentiometric sensor (LAPS), which belongs to the family of semiconductor field-effect devices, was applied for label-free detection of double-stranded deoxyribonucleic acid (dsDNA) molecules by their intrinsic molecular charge. To reduce the distance between the DNA charge and sensor surface and thus, to enhance the electrostatic coupling between the dsDNA molecules and the LAPS, the negatively charged dsDNA molecules were electrostatically adsorbed onto the gate surface of the LAPS covered with a positively charged weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)). The surface potential changes in each spot of the LAPS, induced by the layer-by-layer adsorption of a PAH/dsDNA bilayer, were recorded by means of photocurrent-voltage and constant-photocurrent measurements. In addition, the surface morphology of the gate surface before and after consecutive electrostatic adsorption of PAH and dsDNA layers was studied by atomic force microscopy measurements. Moreover, fluorescence microscopy was used to verify the successful adsorption of dsDNA molecules onto the PAH-modified LAPS surface. A high sensor signal of 25 mV was registered after adsorption of 10 nM dsDNA molecules. The lower detection limit is down to 0.1 nM dsDNA. The obtained results demonstrate that the PAH-modified LAPS device provides a convenient and rapid platform for the direct label-free electrical detection of in-solution hybridized dsDNA molecules.},
  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{DollWagnerWagneretal.2016,
  author    = {Doll, Theodor and Wagner, Torsten and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Engineering of functional interfaces / Theodor Doll ; Torsten Wagner ; Patrick Wagner ; Michael J. Sch{\"o}ning (eds.)},
  series = {Physica status solidi (a)},
  volume    = {213},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201670641},
  pages     = {1393 -- 1394},
  year      = {2016},
  language  = {en}
}
@article{MolinnusSorichBartzetal.2016,
  author    = {Molinnus, Denise and Sorich, Maren and Bartz, Alexander and Siegert, Petra and Willenberg, Holger S. and Lisdat, Fred and Poghossian, Arshak and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Towards an adrenaline biosensor based on substrate recycling amplification in combination with an enzyme logic gate},
  series = {Sensors and Actuators B: Chemical},
  volume    = {237},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2016.06.064},
  pages     = {190 -- 195},
  year      = {2016},
  abstract  = {An amperometric biosensor using a substrate recycling principle was realized for the detection of low adrenaline concentrations (1 nM) by measurements in phosphate buffer and Ringer's solution at pH 6.5 and pH 7.4, respectively. In proof-of-concept experiments, a Boolean logic-gate principle has been applied to develop a digital adrenaline biosensor based on an enzyme AND logic gate. The obtained results demonstrate that the developed digital biosensor is capable for a rapid qualitative determination of the presence/absence of adrenaline in a YES/NO statement. Such digital biosensor could be used in clinical diagnostics for the control of a correct insertion of a catheter in the adrenal veins during adrenal venous-sampling procedure.},
  language  = {en}
}
@article{MiyamotoSatoAbeetal.2016,
  author    = {Miyamoto, Ko-Ichiro and Sato, Takuya and Abe, Minami and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Light-addressable potentiometric sensor as a sensing element in plug-based microfluidic devices},
  series = {Micromachines},
  volume    = {7},
  journal   = {Micromachines},
  number    = {7},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2072-666X},
  doi       = {10.3390/mi7070111},
  pages     = {111},
  year      = {2016},
  abstract  = {A plug-based microfluidic system based on the principle of the light-addressable potentiometric sensor (LAPS) is proposed. The LAPS is a semiconductor-based chemical sensor, which has a free addressability of the measurement point on the sensing surface. By combining a microfluidic device and LAPS, ion sensing can be performed anywhere inside the microfluidic channel. In this study, the sample solution to be measured was introduced into the channel in a form of a plug with a volume in the range of microliters. Taking advantage of the light-addressability, the position of the plug could be monitored and pneumatically controlled. With the developed system, the pH value of a plug with a volume down to 400 nL could be measured. As an example of plug-based operation, two plugs were merged in the channel, and the pH change was detected by differential measurement.},
  language  = {en}
}
@article{BaeckerKochEibenetal.2017,
  author    = {B{\"a}cker, Matthias and Koch, Claudia and Eiben, Sabine and Geiger, Fania and Eber, Fabian and Gliemann, Hartmut and Poghossian, Arshak and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {Tobacco mosaic virus as enzyme nanocarrier for electrochemical biosensors},
  series = {Sensors and Actuators B: Chemical},
  volume    = {238},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2016.07.096},
  pages     = {716 -- 722},
  year      = {2017},
  abstract  = {The conjunction of (bio-)chemical recognition elements with nanoscale biological building blocks such as virus particles is considered as a very promising strategy for the creation of biohybrids opening novel opportunities for label-free biosensing. This work presents a new approach for the development of biosensors using tobacco mosaic virus (TMV) nanotubes or coat proteins (CPs) as enzyme nanocarriers. Sensor chips combining an array of Pt electrodes loaded with glucose oxidase (GOD)-modified TMV nanotubes or CP aggregates were used for amperometric detection of glucose as a model system for the first time. The presence of TMV nanotubes or CPs on the sensor surface allows binding of a high amount of precisely positioned enzymes without substantial loss of their activity, and may also ensure accessibility of their active centers for analyte molecules. Specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CPs was achieved via bioaffinity binding. These layouts were tested in parallel with glucose sensors with adsorptively immobilized [SA]-GOD, as well as [SA]-GOD crosslinked with glutardialdehyde, and came out to exhibit superior sensor performance. The achieved results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for future applications in biosensorics and biochips.},
  language  = {en}
}
@article{PoghossianWernerBuniatyanetal.2017,
  author    = {Poghossian, Arshak and Werner, Frederik and Buniatyan, V. V. and Wagner, Torsten and Miamoto, K. and Yoshinobu, T. and Sch{\"o}ning, Michael Josef},
  title     = {Towards addressability of light-addressable potentiometric sensors: Shunting effect of non-illuminated region and cross-talk},
  series = {Sensor and Actuators B: Chemical},
  journal   = {Sensor and Actuators B: Chemical},
  number    = {244},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2017.01.047},
  pages     = {1071 -- 1079},
  year      = {2017},
  abstract  = {The LAPS (light-addressable potentiometric sensor) platform is one of the most attractive approaches for chemical and biological sensing with many applications ranging from pH and ion/analyte concentration measurements up to cell metabolism detection and chemical imaging. However, although it is generally accepted that LAPS measurements are spatially resolved, the light-addressability feature of LAPS devices has not been discussed in detail so far. In this work, an extended electrical equivalent-circuit model of the LAPS has been presented, which takes into account possible cross-talk effects due to the capacitive coupling of the non-illuminated region. A shunting effect of the non-illuminated area on the measured photocurrent and addressability of LAPS devices has been studied. It has been shown, that the measured photocurrent will be determined not only by the local interfacial potential in the illuminated region but also by possible interfacial potential changes in the non-illuminated region, yielding cross-talk effects. These findings were supported by the experimental investigations of a penicillin-sensitive multi-spot LAPS and a metal-insulator-semiconductor LAPS as model systems.},
  language  = {en}
}
@article{KatzPoghossianSchoening2017,
  author    = {Katz, Evgeny and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Enzyme-based logic gates and circuits - analytical applications and interfacing with electronics},
  series = {Analytical and Bioanalytical Chemistry},
  volume    = {409},
  journal   = {Analytical and Bioanalytical Chemistry},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1618-2650},
  doi       = {10.1007/s00216-016-0079-7},
  pages     = {81 -- 94},
  year      = {2017},
  abstract  = {The paper is an overview of enzyme-based logic gates and their short circuits, with specific examples of Boolean AND and OR gates, and concatenated logic gates composed of multi-step enzyme-biocatalyzed reactions. Noise formation in the biocatalytic reactions and its decrease by adding a "filter" system, converting convex to sigmoid response function, are discussed. Despite the fact that the enzyme-based logic gates are primarily considered as components of future biomolecular computing systems, their biosensing applications are promising for immediate practical use. Analytical use of the enzyme logic systems in biomedical and forensic applications is discussed and exemplified with the logic analysis of biomarkers of various injuries, e.g., liver injury, and with analysis of biomarkers characteristic of different ethnicity found in blood samples on a crime scene. Interfacing of enzyme logic systems with modified electrodes and semiconductor devices is discussed, giving particular attention to the interfaces functionalized with signal-responsive materials. Future perspectives in the design of the biomolecular logic systems and their applications are discussed in the conclusion.},
  language  = {en}
}
@article{HonarvarfardGamellaChannaveerappaetal.2017,
  author    = {Honarvarfard, Elham and Gamella, Maria and Channaveerappa, Devika and Darie, Costel C. and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {Electrochemically Stimulated Insulin Release from a Modified Graphene-functionalized Carbon Fiber Electrode},
  series = {Electroanalysis},
  volume    = {29},
  journal   = {Electroanalysis},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-4109},
  doi       = {10.1002/elan.201700095},
  pages     = {1543 -- 1553},
  year      = {2017},
  abstract  = {A graphene-functionalized carbon fiber electrode was modified with adsorbed polyethylenimine to introduce amino functionalities and then with trigonelline and 4-carboxyphenylboronic acid covalently bound to the amino groups. The trigonelline species containing quarterized pyridine groups produced positive charge on the electrode surface regardless of the pH value, while the phenylboronic acid species were neutral below pH 8 and negatively charged above pH 9 (note that their pKa=8.4). The total charge on the monolayer-modified electrode was positive at the neutral pH and negative at pH > 9. Note that 4-carboxyphenylboronic acid was attached to the electrode surface in molar excess to trigonelline, thus allowing the negative charge to dominate on the electrode surface at basic pH. Negatively charged fluorescent dye-labeled insulin (insulin-FITC) was loaded on the modified electrode surface at pH 7.0 due to its electrostatic attraction to the positively charged interface. The local pH in close vicinity to the electrode surface was increased to ca. 9-10 due to consumption of H+ ions upon electrochemical reduction of oxygen proceeding at the potential of -1.0 V (vs. Ag/AgCl) applied on the modified electrode. The process resulted in recharging of the electrode surface to the negative value due to the formation of the negative charge on the phenylboronic acid groups, thus resulting in the electrostatic repulsion of insulin-FITC and stimulating its release from the electrode surface. The insulin release was characterized by fluorescence spectroscopy (using the FITC-labeled insulin), by electrochemical measurements on an iridium oxide, IrOx, electrode and by mass spectrometry. The graphene-functionalized carbon fiber electrode demonstrated significant advantages in the signal-stimulated insulin release comparing with the carbon fiber electrode without the graphene species.},
  language  = {en}
}
@article{GamellaZakharchenkoGuzetal.2017,
  author    = {Gamella, Maria and Zakharchenko, Andrey and Guz, Nataliia and Masi, Madeline and Minko, Sergiy and Kolpashchikov, Dmitry M. and Iken, Heiko and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {DNA computing system activated by electrochemically triggered DNA realease from a polymer-brush-modified electrode array},
  series = {Electroanalysis},
  volume    = {29},
  journal   = {Electroanalysis},
  number    = {2},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-4109},
  doi       = {10.1002/elan.201600389},
  pages     = {398 -- 408},
  year      = {2017},
  abstract  = {An array of four independently wired indium tin oxide (ITO) electrodes was used for electrochemically stimulated DNA release and activation of DNA-based Identity, AND and XOR logic gates. Single-stranded DNA molecules were loaded on the mixed poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA)/poly(methacrylic acid) (PMAA) brush covalently attached to the ITO electrodes. The DNA deposition was performed at pH 5.0 when the polymer brush is positively charged due to protonation of tertiary amino groups in PDMAEMA, thus resulting in electrostatic attraction of the negatively charged DNA. By applying electrolysis at -1.0 V(vs. Ag/AgCl reference) electrochemical oxygen reduction resulted in the consumption of hydrogen ions and local pH increase near the electrode surface. The process resulted in recharging the polymer brush to the negative state due to dissociation of carboxylic groups of PMAA, thus repulsing the negatively charged DNA and releasing it from the electrode surface. The DNA release was performed in various combinations from different electrodes in the array assembly. The released DNA operated as input signals for activation of the Boolean logic gates. The developed system represents a step forward in DNA computing, combining for the first time DNA chemical processes with electronic input signals.},
  language  = {en}
}