@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{BaeckerPouyeshmanSchnitzleretal.2011,
  author    = {B{\"a}cker, Matthias and Pouyeshman, S. and Schnitzler, Thomas and Poghossian, Arshak and Wagner, Patrick and Biselli, Manfred and Sch{\"o}ning, Michael Josef},
  title     = {A silicon-based multi-sensor chip for monitoring of fermentation processes},
  series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6},
  journal   = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6},
  publisher = {Wiley},
  address   = {Weinheim},
  isbn      = {1862-6319},
  pages     = {1364 -- 1369},
  year      = {2011},
  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{BaeckerPoghossianAbouzaretal.2010,
  author    = {B{\"a}cker, Matthias and Poghossian, Arshak and Abouzar, Maryam H. and Wenmackers, Sylvia and Janssens, Stoffel D. and Haenen, Ken and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Capacitive field-effect (bio-)chemical sensors based on nanocrystalline diamond films},
  series = {Diamond Electronics and Bioelectronics — Fundamentals to Applications III, edited by P. Bergonzo, [u.a.]},
  journal   = {Diamond Electronics and Bioelectronics — Fundamentals to Applications III, edited by P. Bergonzo, [u.a.]},
  pages     = {1 -- 6},
  year      = {2010},
  language  = {en}
}
@article{KarschuckPoghossianSeretal.2024,
  author    = {Karschuck, Tobias and Poghossian, Arshak and Ser, Joey and Tsokolakyan, Astghik and Achtsnicht, Stefan and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Capacitive model of enzyme-modified field-effect biosensors: Impact of enzyme coverage},
  series = {Sensors and Actuators B: Chemical},
  volume    = {408},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005 (Print)},
  doi       = {10.1016/j.snb.2024.135530},
  pages     = {12 Seiten},
  year      = {2024},
  abstract  = {Electrolyte-insulator-semiconductor capacitors (EISCAP) belong to field-effect sensors having an attractive transducer architecture for constructing various biochemical sensors. In this study, a capacitive model of enzyme-modified EISCAPs has been developed and the impact of the surface coverage of immobilized enzymes on its capacitance-voltage and constant-capacitance characteristics was studied theoretically and experimentally. The used multicell arrangement enables a multiplexed electrochemical characterization of up to sixteen EISCAPs. Different enzyme coverages have been achieved by means of parallel electrical connection of bare and enzyme-covered single EISCAPs in diverse combinations. As predicted by the model, with increasing the enzyme coverage, both the shift of capacitance-voltage curves and the amplitude of the constant-capacitance signal increase, resulting in an enhancement of analyte sensitivity of the EISCAP biosensor. In addition, the capability of the multicell arrangement with multi-enzyme covered EISCAPs for sequentially detecting multianalytes (penicillin and urea) utilizing the enzymes penicillinase and urease has been experimentally demonstrated and discussed.},
  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{SchusserPoghossianBaeckeretal.2012,
  author    = {Schusser, Sebastian and Poghossian, Arshak and B{\"a}cker, Matthias and Leinhos, Marcel and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Characterization of biodegradable polymers with capacitive field-effect sensors},
  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.2012.07.099},
  pages     = {2 -- 7},
  year      = {2012},
  abstract  = {In vitro studies of the degradation kinetic of biopolymers are essential for the design and optimization of implantable biomedical devices. In the presented work, a field-effect capacitive sensor has been applied for the real-time and in situ monitoring of degradation processes of biopolymers for the first time. The polymer-covered field-effect sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by degradation processes. The feasibility of this approach has been experimentally proven by using the commercially available biomedical polymer poly(D,L-lactic acid) (PDLLA) as a model system. PDLLA films of different thicknesses were deposited on the Ta₂O₅-gate surface of the field-effect structure from a polymer solution by means of spin-coating method. The polymer-modified field-effect sensors have been characterized by means of capacitance-voltage and impedance-spectroscopy method. The degradation of the PDLLA was accelerated by changing the degradation medium from neutral (pH 7.2) to alkaline (pH 9) condition, resulting in drastic changes in the capacitance and impedance spectra of the polymer-modified field-effect sensor.},
  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{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{BaeckerBegingBisellietal.2009,
  author    = {B{\"a}cker, Matthias and Beging, Stefan and Biselli, Manfred and Poghossian, Arshak and Wang, J. and Zang, Werner and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Concept for a solid-state multi-parameter sensor system for cell-culture monitoring},
  series = {Electrochimica Acta. 54 (2009), H. 25 Sp. Iss. SI},
  journal   = {Electrochimica Acta. 54 (2009), H. 25 Sp. Iss. SI},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {0013-4686},
  pages     = {6107 -- 6112},
  year      = {2009},
  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{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{DantismTakenagaWagneretal.2017,
  author    = {Dantism, Shahriar and Takenaga, Shoko and Wagner, Torsten and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Differential imaging of the metabolism of bacteria and eukaryotic cells based on light-addressable potentiometric sensors},
  series = {Electrochimica Acta},
  volume    = {246},
  journal   = {Electrochimica Acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0013-4686},
  doi       = {10.1016/j.electacta.2017.05.196},
  pages     = {234 -- 241},
  year      = {2017},
  abstract  = {A light-addressable potentiometric sensor (LAPS) is a field-effect-based potentiometric sensor with an electrolyte/insulator/semiconductor (EIS) structure, which is able to monitor analyte concentrations of (bio-)chemical species in aqueous solutions in a spatially resolved way. Therefore, it is also an appropriate tool to record 2D-chemical images of concentration variations on the sensor surface. In the present work, two differential, LAPS-based measurement principles are introduced to determine the metabolic activity of Escherichia coli (E. coli) K12 and Chinese hamster ovary (CHO) cells as test microorganisms. Hereby, we focus on i) the determination of the extracellular acidification rate (ΔpH/min) after adding glucose solutions to the cell suspensions; and ii) recording the amplitude increase of the photocurrent (Iph) related to the produced acids from E. coli K12 bacteria and CHO cells on the sensor surface by 2D-chemical imaging. For this purpose, 3D-printed multi-chamber structures were developed and mounted on the planar sensor-chip surface to define four independent compartments, enabling differential measurements with varying cell concentrations. The differential concept allows eliminating unwanted drift effects and, with the four-chamber structures, measurements on the different cell concentrations were performed simultaneously, thus reducing also the overall measuring time.},
  language  = {en}
}
@article{WeldenSchejaSchoeningetal.2018,
  author    = {Welden, Rene and Scheja, Sabrina and Sch{\"o}ning, Michael Josef and Wagner, Patrick and Wagner, Torsten},
  title     = {Electrochemical Evaluation of Light-Addressable Electrodes Based on TiO2 for the Integration in Lab-on-Chip Systems},
  series = {physica status solidi a : applications and materials sciences},
  volume    = {215},
  journal   = {physica status solidi a : applications and materials sciences},
  number    = {15},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201800150},
  pages     = {Article number 1800150},
  year      = {2018},
  abstract  = {In lab-on-chip systems, electrodes are important for the manipulation (e.g., cell stimulation, electrolysis) within such systems. An alternative to commonly used electrode structures can be a light-addressable electrode. Here, due to the photoelectric effect, the conducting area can be adjusted by modification of the illumination area which enables a flexible control of the electrode. In this work, titanium dioxide based light-addressable electrodes are fabricated by a sol-gel technique and a spin-coating process, to deposit a thin film on a fluorine-doped tin oxide glass. To characterize the fabricated electrodes, the thickness, and morphological structure are measured by a profilometer and a scanning electron microscope. For the electrochemical behavior, the dark current and the photocurrent are determined for various film thicknesses. For the spatial resolution behavior, the dependency of the photocurrent while changing the area of the illuminated area is studied. Furthermore, the addressing of single fluid compartments in a three-chamber system, which is added to the electrode, is demonstrated.},
  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{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{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{BohrnStuetzFleischeretal.2011,
  author    = {Bohrn, Ulrich and St{\"u}tz, Evamaria and Fleischer, Maximilian and Sch{\"o}ning, Michael Josef and Wagner, Patrick},
  title     = {Eukaryotic cell lines as a sensitive layer for direct monitoring of carbon monoxide},
  series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6},
  journal   = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6},
  publisher = {Wiley},
  address   = {Weinheim},
  isbn      = {1862-6319},
  pages     = {1345 -- 1350},
  year      = {2011},
  language  = {en}
}
@article{GrinsvenBonStrauvenetal.2012,
  author    = {Grinsven, Bart van and Bon, Natalie vanden and Strauven, Hannelore and Grieten, Lars and Murib, Mohammed and Jim{\´e}nez Monroy, Kathia L. and Janssens, Stoffel D. and Haenen, Ken and Sch{\"o}ning, Michael Josef and Vermeeren, Veronique and Ameloot, Marcel and Michiels, Luc and Thoelen, Ronald and Ceuninck, Ward de and Wagner, Patrick},
  title     = {Heat-Transfer Resistance at Solid-Liquid Interfaces: A Tool for The Detection of Single Nucleotide Polymorphisms in DNA.},
  series = {ACS Nano},
  volume    = {6},
  journal   = {ACS Nano},
  number    = {3},
  publisher = {ACS Publications},
  address   = {Washington, DC},
  issn      = {1936-086X},
  doi       = {10.1021/nn300147e},
  pages     = {2712 -- 2721},
  year      = {2012},
  abstract  = {In this article, we report on the heat-transfer resistance at interfaces as a novel, denaturation-based method to detect single-nucleotide polymorphisms in DNA. We observed that a molecular brush of double-stranded DNA grafted onto synthetic diamond surfaces does not notably affect the heat-transfer resistance at the solid-to-liquid interface. In contrast to this, molecular brushes of single-stranded DNA cause, surprisingly, a substantially higher heat-transfer resistance and behave like a thermally insulating layer. This effect can be utilized to identify ds-DNA melting temperatures via the switching from low- to high heat-transfer resistance. The melting temperatures identified with this method for different DNA duplexes (29 base pairs without and with built-in mutations) correlate nicely with data calculated by modeling. The method is fast, label-free (without the need for fluorescent or radioactive markers), allows for repetitive measurements, and can also be extended toward array formats. Reference measurements by confocal fluorescence microscopy and impedance spectroscopy confirm that the switching of heat-transfer resistance upon denaturation is indeed related to the thermal on-chip denaturation of DNA.},
  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}
}