@article{PoghossianPlatenSchoening2005,
  author    = {Poghossian, Arshak and Platen, J. and Sch{\"o}ning, Michael Josef},
  title     = {Towards self-aligned nanostructures by means of layerexpansion technique},
  series = {Electrochimica Acta. 51 (2005), H. 5},
  journal   = {Electrochimica Acta. 51 (2005), H. 5},
  isbn      = {0013-4686},
  pages     = {838 -- 843},
  year      = {2005},
  language  = {en}
}
@article{MolinnusIkenJohnenetal.2022,
  author    = {Molinnus, Denise and Iken, Heiko and Johnen, Anna Lynn and Richstein, Benjamin and Hellmich, Lena and Poghossian, Arshak and Knoch, Joachim and Sch{\"o}ning, Michael Josef},
  title     = {Miniaturized pH-Sensitive Field-Effect Capacitors with Ultrathin Ta₂O₅ Films Prepared by Atomic Layer Deposition},
  series = {physica status solidi (a) applications and materials science},
  volume    = {219},
  journal   = {physica status solidi (a) applications and materials science},
  number    = {8},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.202100660},
  pages     = {7 Seiten},
  year      = {2022},
  abstract  = {Miniaturized electrolyte-insulator-semiconductor capacitors (EISCAPs) with ultrathin gate insulators have been studied in terms of their pH-sensitive sensor characteristics: three different EISCAP systems consisting of Al-p-Si-Ta2O5(5 nm), Al-p-Si-Si3N4(1 or 2 nm)-Ta2O5 (5 nm), and Al-p-Si-SiO2(3.6 nm)-Ta2O5(5 nm) layer structures are characterized in buffer solution with different pH values by means of capacitance-voltage and constant capacitance method. The SiO2 and Si3N4 gate insulators are deposited by rapid thermal oxidation and rapid thermal nitridation, respectively, whereas the Ta2O5 film is prepared by atomic layer deposition. All EISCAP systems have a clear pH response, favoring the stacked gate insulators SiO2-Ta2O5 when considering the overall sensor characteristics, while the Si3N4(1 nm)-Ta2O5 stack delivers the largest accumulation capacitance (due to the lower equivalent oxide thickness) and a higher steepness in the slope of the capacitance-voltage curve among the studied stacked gate insulator systems.},
  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{BaeckerRaueSchusseretal.2012,
  author    = {B{\"a}cker, Matthias and Raue, Markus and Schusser, Sebastian and Jeitner, C. and Breuer, L. and Wagner, P. and Poghossian, Arshak and F{\"o}rster, Arnold and Mang, Thomas and Sch{\"o}ning, Michael Josef},
  title     = {Microfluidic chip with integrated microvalves based on temperature- and pH-responsive hydrogel thin films},
  series = {Physica Status Solidi (a)},
  volume    = {209},
  journal   = {Physica Status Solidi (a)},
  number    = {5},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201100763},
  pages     = {839 -- 845},
  year      = {2012},
  abstract  = {Two types of microvalves based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) and pH-responsive poly(sodium acrylate) (PSA) hydrogel films have been developed and tested. The PNIPAAm and PSA hydrogel films were prepared by means of in situ photopolymerization directly inside the fluidic channel of a microfluidic chip fabricated by combining Si and SU-8 technologies. The swelling/shrinking properties and height changes of the PNIPAAm and PSA films inside the fluidic channel were studied at temperatures of deionized water from 14 to 36 °C and different pH values (pH 3-12) of Titrisol buffer, respectively. Additionally, in separate experiments, the lower critical solution temperature (LCST) of the PNIPAAm hydrogel was investigated by means of a differential scanning calorimetry (DSC) and a surface plasmon resonance (SPR) method. Mass-flow measurements have shown the feasibility of the prepared hydrogel films to work as an on-chip integrated temperature- or pH-responsive microvalve capable to switch the flow channel on/off.},
  language  = {en}
}
@article{BronderPoghossianKeusgenetal.2017,
  author    = {Bronder, Thomas and Poghossian, Arshak and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Label-free detection of double-stranded DNA molecules with polyelectrolyte-modified capacitive field-effect sensors},
  series = {tm - Technisches Messen},
  volume    = {84},
  journal   = {tm - Technisches Messen},
  number    = {10},
  publisher = {De Gruyter},
  address   = {Oldenbourg},
  doi       = {10.1515/teme-2017-0015},
  pages     = {628 -- 634},
  year      = {2017},
  abstract  = {In this study, polyelectrolyte-modified field-effect-based electrolyte-insulator-semiconductor (EIS) devices have been used for the label-free electrical detection of double-stranded deoxyribonucleic acid (dsDNA)molecules. The sensor-chip functionalization with a positively charged polyelectrolyte layer provides the possibility of direct adsorptive binding of negatively charged target DNA oligonucleotides onto theSiO2-chip surface.EIS sensors can be utilized as a tool to detect surface-charge changes; the electrostatic adsorption of oligonucleotides onto the polyelectrolyte layer leads to a measureable surface-potential change. Signals of 39mV have been recorded after the incubation with the oligonucleotide solution. Besides the electrochemical experiments, the successful adsorption of dsDNA onto the polyelectrolyte layer has been verified via fluorescence microscopy. The presented results demonstrate that the signal recording of EISchips, which are modified with a polyelectrolyte layer, canbe used as a favorable approach for a fast, cheap and simple detection method for dsDNA.},
  language  = {en}
}
@article{JablonskiPoghossianSeverinetal.2021,
  author    = {Jablonski, Melanie and Poghossian, Arshak and Severin, Robin and Keusgen, Michael and Wege, Christian and Sch{\"o}ning, Michael Josef},
  title     = {Capacitive Field-Effect Biosensor Studying Adsorption of Tobacco Mosaic Virus Particles},
  series = {Micromachines},
  volume    = {12},
  journal   = {Micromachines},
  number    = {1},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/mi12010057},
  pages     = {Artikel 57},
  year      = {2021},
  abstract  = {Plant virus-like particles, and in particular, tobacco mosaic virus (TMV) particles, are increasingly being used in nano- and biotechnology as well as for biochemical sensing purposes as nanoscaffolds for the high-density immobilization of receptor molecules. The sensitive parameters of TMV-assisted biosensors depend, among others, on the density of adsorbed TMV particles on the sensor surface, which is affected by both the adsorption conditions and surface properties of the sensor. In this work, Ta₂O₅-gate field-effect capacitive sensors have been applied for the label-free electrical detection of TMV adsorption. The impact of the TMV concentration on both the sensor signal and the density of TMV particles adsorbed onto the Ta₂O₅-gate surface has been studied systematically by means of field-effect and scanning electron microscopy methods. In addition, the surface density of TMV particles loaded under different incubation times has been investigated. Finally, the field-effect sensor also demonstrates the label-free detection of penicillinase immobilization as model bioreceptor on TMV particles.},
  language  = {en}
}
@article{SchoeningAbouzarPoghossian2009,
  author    = {Sch{\"o}ning, Michael Josef and Abouzar, Maryam H. and Poghossian, Arshak},
  title     = {pH and ion sensitivity of a field-effect EIS (electrolyte-insulator-semiconductor) sensor covered with polyelectrolyte multilayers},
  series = {Journal of Solid State Electrochemistry. 13 (2009), H. 1},
  journal   = {Journal of Solid State Electrochemistry. 13 (2009), H. 1},
  isbn      = {1433-0768},
  pages     = {115 -- 122},
  year      = {2009},
  language  = {en}
}
@article{BaeckerKowollikSchnitzleretal.2009,
  author    = {B{\"a}cker, Matthias and Kowollik, Silvia and Schnitzler, Thomas and Wang, J. and Poghossian, Arshak and Zang, Werner and Biselli, Manfred and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Entwicklung eines festk{\"o}rperbasierten Sensorsystems f{\"u}r die Bioprozessautomatisierung},
  series = {9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]},
  journal   = {9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]},
  publisher = {TUDpress},
  address   = {Dresden},
  isbn      = {978-3-941298-44-6},
  pages     = {197 -- 200},
  year      = {2009},
  language  = {de}
}
@article{SchoeningPoghossianYoshinobuetal.2001,
  author    = {Sch{\"o}ning, Michael Josef and Poghossian, Arshak and Yoshinobu, Tatsuo and L{\"u}th, Hans},
  title     = {Semiconductor-based field-effect structures for chemical sensing},
  pages     = {188 -- 198},
  year      = {2001},
  language  = {en}
}
@inproceedings{HuckPoghossianBaeckeretal.2013,
  author    = {Huck, Christina and Poghossian, Arshak and B{\"a}cker, Matthias and Zander, W. and Schubert, J. and Sukoyan, L. H. and Begoyan, V. and Buniatyan, V. V. and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Chemische Sensoren mit Bariumstrontiumtitanat als funktionelle Schicht zur Multiparameterdetektion},
  series = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  booktitle = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  organization    = {Dresdner Sensor-Symposium <11, 2013>},
  isbn      = {978-3-9813484-5-3},
  pages     = {368 -- 372},
  year      = {2013},
  language  = {de}
}
@inproceedings{SchusserBaeckerLeinhosetal.2013,
  author    = {Schusser, Sebastian and B{\"a}cker, Matthias and Leinhos, Marcel and Krischer, M. and Wenzel, L. and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Sensorkonzept zur in vitro Echtzeitmessung des Degradationsverhaltens von biodegradierbaren Biopolymeren},
  series = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  booktitle = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  organization    = {Dresdner Sensor-Symposium <11, 2013>},
  isbn      = {978-3-9813484-5-3},
  pages     = {174 -- 177},
  year      = {2013},
  language  = {de}
}
@article{KochPoghossianSchoeningetal.2018,
  author    = {Koch, Claudia and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Wege, Christian},
  title     = {Penicillin Detection by Tobacco Mosaic Virus-Assisted Colorimetric Biosensors},
  series = {Nanotheranostics},
  volume    = {2},
  journal   = {Nanotheranostics},
  number    = {2},
  publisher = {Ivyspring},
  address   = {Sydney},
  issn      = {2206-7418},
  doi       = {10.7150/ntno.22114},
  pages     = {184 -- 196},
  year      = {2018},
  abstract  = {The presentation of enzymes on viral scaffolds has beneficial effects such as an increased enzyme loading and a prolonged reusability in comparison to conventional immobilization platforms. Here, we used modified tobacco mosaic virus (TMV) nanorods as enzyme carriers in penicillin G detection for the first time. Penicillinase enzymes were conjugated with streptavidin and coupled to TMV rods by use of a bifunctional biotin-linker. Penicillinase-decorated TMV particles were characterized extensively in halochromic dye-based biosensing. Acidometric analyte detection was performed with bromcresol purple as pH indicator and spectrophotometry. The TMV-assisted sensors exhibited increased enzyme loading and strongly improved reusability, and higher analysis rates compared to layouts without viral adapters. They extended the half-life of the sensors from 4 - 6 days to 5 weeks and thus allowed an at least 8-fold longer use of the sensors. Using a commercial budget-priced penicillinase preparation, a detection limit of 100 µM penicillin was obtained. Initial experiments also indicate that the system may be transferred to label-free detection layouts.},
  language  = {en}
}
@article{PoghossianThustSchoeningetal.2000,
  author    = {Poghossian, Arshak and Thust, M. and Sch{\"o}ning, Michael Josef and M{\"u}ller-Veggian, Mattea and Kordos, P. and L{\"u}th, H.},
  title     = {Cross-sensitivity of a capacitive penicillin sensor combined with a diffusion barrier},
  series = {Sensors and Actuators B. 68 (2000), H. 1-3},
  journal   = {Sensors and Actuators B. 68 (2000), H. 1-3},
  isbn      = {0925-4005},
  pages     = {260 -- 265},
  year      = {2000},
  language  = {en}
}
@article{SchoeningBrinkmannDemuthetal.2004,
  author    = {Sch{\"o}ning, Michael Josef and Brinkmann, D. and Demuth, C. and Poghossian, Arshak},
  title     = {CIP (cleaning-in-place)-suitable „non-glass" pH sensor based on a Ta2O5-gate EIS structure},
  series = {Digest of technical papers : September 12 - 15, 2004, Rome, Italy, Pontificia Universitas Sancto Thoma Aquinate in Urbe / [conference chairperson: C. Di Natale].},
  journal   = {Digest of technical papers : September 12 - 15, 2004, Rome, Italy, Pontificia Universitas Sancto Thoma Aquinate in Urbe / [conference chairperson: C. Di Natale].},
  address   = {Roma},
  isbn      = {88-7621-282-5},
  pages     = {857 -- 860},
  year      = {2004},
  language  = {en}
}
@article{PoghossianBerndsenLuethetal.2001,
  author    = {Poghossian, Arshak and Berndsen, Lars and L{\"u}th, Hans and Sch{\"o}ning, Michael Josef},
  title     = {Novel concepts for flow-rate and flow-direction determination by means of pH-sensitive ISFETs},
  series = {Proceedings of SPIE. 4560 (2001)},
  journal   = {Proceedings of SPIE. 4560 (2001)},
  pages     = {19 -- 27},
  year      = {2001},
  language  = {en}
}
@article{HonarvarfardGamellaPoghossianetal.2017,
  author    = {Honarvarfard, Elham and Gamella, Maria and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {An enzyme-based reversible Controlled NOT (CNOT) logic gate operating on a semiconductor transducer},
  series = {Applied Materials Today},
  volume    = {9},
  journal   = {Applied Materials Today},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2352-9407},
  doi       = {10.1016/j.apmt.2017.08.003},
  pages     = {266 -- 270},
  year      = {2017},
  abstract  = {An enzyme-based biocatalytic system mimicking operation of a logically reversible Controlled NOT (CNOT) gate has been interfaced with semiconductor electronic transducers. Electrolyte-insulator-semiconductor (EIS) structures have been used to transduce chemical changes produced by the enzyme system to an electronically readable capacitive output signal using field-effect features of the EIS device. Two enzymes, urease and esterase, were immobilized on the insulating interface of EIS structure producing local pH changes performing XOR logic operation controlled by various combinations of the input signals represented by urea and ethyl butyrate. Another EIS transducer was functionalized with esterase only, thus performing Identity (ID) logic operation for the ethyl butyrate input. Both semiconductor devices assembled in parallel operated as a logically reversible CNOT gate. The present system, despite its simplicity, demonstrated for the first time logically reversible function of the enzyme system transduced electronically with the semiconductor devices. The biomolecular realization of a CNOT gate interfaced with semiconductors is promising for integration into complex biomolecular networks and future biosensor/biomedical applications.},
  language  = {en}
}
@article{WagnerBegingRotteretal.2007,
  author    = {Wagner, Torsten and Beging, Stefan and Rotter, L. and Poghossian, Arshak and Biselli, Manfred and Zang, Werner and Sch{\"o}ning, Michael Josef},
  title     = {Online-Messsysteme f{\"u}r die automatisierte Charakterisierung von feldeffektbasierten Biosensoren},
  series = {8. Dresdner Sensor-Symposium : Sensoren f{\"u}r Umwelt, Klima und Sicherheit, Biosensoren und Biosysteme, Sensoren und Sensorsysteme f{\"u}r die Prozesstechnik, Trends in der Sensortechnik, Materialentwicklung f{\"u}r die Sensorik; 8. Dresdner Sensor-Symposium, 10. - 12. Dezember 2007, Dresden / Gerald Gerlach ... (Hg.)},
  journal   = {8. Dresdner Sensor-Symposium : Sensoren f{\"u}r Umwelt, Klima und Sicherheit, Biosensoren und Biosysteme, Sensoren und Sensorsysteme f{\"u}r die Prozesstechnik, Trends in der Sensortechnik, Materialentwicklung f{\"u}r die Sensorik; 8. Dresdner Sensor-Symposium, 10. - 12. Dezember 2007, Dresden / Gerald Gerlach ... (Hg.)},
  publisher = {TUDpress, Verl. der Wissenschaften},
  address   = {Dresden},
  isbn      = {978-3-940046-45-1},
  pages     = {257 -- 260},
  year      = {2007},
  language  = {de}
}
@article{YoshinobuEckenPoghossianetal.2001,
  author    = {Yoshinobu, T. and Ecken, H. and Poghossian, Arshak and Simonis, A. and Iwasaki, H. and L{\"u}th, H. and Sch{\"o}ning, Michael Josef},
  title     = {Constant-current-mode LAPS (CLAPS) for the detection of penicillin},
  series = {Electroanalysis. 13 (2001), H. 8-9},
  journal   = {Electroanalysis. 13 (2001), H. 8-9},
  isbn      = {1040-0397},
  pages     = {733 -- 736},
  year      = {2001},
  language  = {en}
}
@article{PoghossianAbouzarSchoening2008,
  author    = {Poghossian, Arshak and Abouzar, Maryam H. and Sch{\"o}ning, Michael Josef},
  title     = {Capacitance-voltage and impedance characteristics of field-effect EIS sensors functionalised with polyelectrolyte multilayers},
  series = {IRBM. 29 (2008), H. 2-3},
  journal   = {IRBM. 29 (2008), H. 2-3},
  isbn      = {1959-0318},
  pages     = {149 -- 154},
  year      = {2008},
  language  = {en}
}
@article{PoghossianLuethSchultzeetal.2001,
  author    = {Poghossian, Arshak and L{\"u}th, H. and Schultze, J. W. and Sch{\"o}ning, Michael Josef},
  title     = {(Bio-)chemical and physical microsensor array using an identical transducer principle},
  series = {Scaling down in electrochemistry : electrochemical micro- and nanosystem technology ; proceedings of the 3rd International Symposium on Electrochemical Microsystem Technologies, Garmisch-Patenkirchen, Germany, 11 - 15 September 2000 / ed. by J. W. Schultz},
  journal   = {Scaling down in electrochemistry : electrochemical micro- and nanosystem technology ; proceedings of the 3rd International Symposium on Electrochemical Microsystem Technologies, Garmisch-Patenkirchen, Germany, 11 - 15 September 2000 / ed. by J. W. Schultz},
  publisher = {Elsevier [u.a.]},
  address   = {Amsterdam [u.a.]},
  isbn      = {0-08-044014-2},
  pages     = {243 -- 249},
  year      = {2001},
  language  = {en}
}
@article{SchoeningPoghossian2006,
  author    = {Sch{\"o}ning, Michael Josef and Poghossian, Arshak},
  title     = {BioFEDs (field-effect devices) : State-of-the-art and new directions},
  series = {Electroanalysis},
  volume    = {18},
  journal   = {Electroanalysis},
  number    = {19-20},
  issn      = {1521-4109},
  doi       = {10.1002/elan.200603609},
  pages     = {1893 -- 1900},
  year      = {2006},
  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{RolkaPoghossianSchoening2004,
  author    = {Rolka, David and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Integration of a capacitive EIS sensor into a FIA system for pH and penicillin determination},
  series = {Sensors. 4 (2004)},
  journal   = {Sensors. 4 (2004)},
  isbn      = {1424-8220},
  pages     = {84 -- 94},
  year      = {2004},
  language  = {en}
}
@article{PoghossianSchoening2004,
  author    = {Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Detecting Both Physical and (Bio-)Chemical Parameters by Means of ISFET Devices},
  series = {Electroanalysis. 16 (2004), H. 22},
  journal   = {Electroanalysis. 16 (2004), H. 22},
  isbn      = {1040-0397},
  pages     = {1863 -- 1872},
  year      = {2004},
  language  = {en}
}
@incollection{KochPoghossianWegeetal.2018,
  author    = {Koch, Claudia and Poghossian, Arshak and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {TMV-Based Adapter Templates for Enhanced Enzyme Loading in Biosensor Applications},
  series = {Virus-Derived Nanoparticles for Advanced Technologies},
  booktitle = {Virus-Derived Nanoparticles for Advanced Technologies},
  editor    = {Wege, Christina},
  publisher = {Humana Press},
  address   = {New York, NY},
  isbn      = {978-1-4939-7808-3},
  doi       = {10.1007/978-1-4939-7808-3},
  pages     = {553 -- 568},
  year      = {2018},
  abstract  = {Nanotubular tobacco mosaic virus (TMV) particles and RNA-free lower-order coat protein (CP) aggregates have been employed as enzyme carriers in different diagnostic layouts and compared for their influence on biosensor performance. In the following, we describe a label-free electrochemical biosensor for improved glucose detection by use of TMV adapters and the enzyme glucose oxidase (GOD). A specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CP aggregates was achieved via bioaffinity binding. Glucose sensors with adsorptively immobilized [SA]-GOD, and with [SA]-GOD cross-linked with glutardialdehyde, respectively, were tested in parallel on the same sensor chip. Comparison of these sensors revealed that TMV adapters enhanced the amperometric glucose detection remarkably, conveying highest sensitivity, an extended linear detection range and fastest response times. These results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for applications in biosensorics and biochips. Here, we describe the fabrication and use of amperometric sensor chips combining an array of circular Pt electrodes, their loading with GOD-modified TMV nanotubes (and other GOD immobilization methods), and the subsequent investigations of the sensor performance.},
  language  = {en}
}
@article{SiqueiraAbouzarPoghossianetal.2009,
  author    = {Siqueira, Jos{\´e} R. Jr. and Abouzar, Maryam H. and Poghossian, Arshak and Zucolotto, Valtencir and Oliveira, Osvaldo N. Jr. and Sch{\"o}ning, Michael Josef},
  title     = {Penicillin biosensor based on a capacitive field-effect structure functionalized with a dendrimer/carbon nanotube multilayer},
  series = {Biosensors and Bioelectronics. 25 (2009), H. 2},
  journal   = {Biosensors and Bioelectronics. 25 (2009), H. 2},
  isbn      = {0956-5663},
  pages     = {497 -- 501},
  year      = {2009},
  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}
}
@article{AbouzarPoghossianRazavietal.2008,
  author    = {Abouzar, Maryam H. and Poghossian, Arshak and Razavi, Arash and Besmehn, Astrid and Bijnens, Nathalie and Williams, Oliver A. and Haenen, Ken and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Penicillin detection with nanocrystalline-diamond field-effect sensor},
  series = {physica status solidi (a). 205 (2008), H. 9},
  journal   = {physica status solidi (a). 205 (2008), H. 9},
  isbn      = {1862-6319},
  pages     = {2141 -- 2145},
  year      = {2008},
  language  = {en}
}
@article{AbouzarIngebrandtPoghossianetal.2009,
  author    = {Abouzar, Maryam H. and Ingebrandt, S. and Poghossian, Arshak and Zhang, Y. and Moritz, W. and Sch{\"o}ning, Michael Josef},
  title     = {Field-effect nanoplate capacitive pH sensor based on SOI structure},
  series = {Semiconductor micro- and nanoelectronics : Proceedings of the Seventh International Conference , Tsakhcadzor, Armenia July 3-5 2009},
  journal   = {Semiconductor micro- and nanoelectronics : Proceedings of the Seventh International Conference , Tsakhcadzor, Armenia July 3-5 2009},
  pages     = {55 -- 58},
  year      = {2009},
  language  = {en}
}
@article{PoghossianSchoening2003,
  author    = {Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {"High-order" hybrid FET module for (bio)chemical and physical sensing},
  series = {Integrated analytical systems / ed. by Salvador Alegret},
  journal   = {Integrated analytical systems / ed. by Salvador Alegret},
  publisher = {Elsevier},
  address   = {Amsterdam [u.a.]},
  isbn      = {0-444-51037-0},
  pages     = {587 -- 623},
  year      = {2003},
  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{BegingMlynekHataihimakuletal.2010,
  author    = {Beging, Stefan and Mlynek, Daniela and Hataihimakul, Sudkanung and Poghossian, Arshak and Baldsiefen, Gerhard and Busch, Heinz and Laube, Norbert and Kleinen, Lisa and Sch{\"o}ning, Michael Josef},
  title     = {Field-effect calcium sensor for the determination of the risk of urinary stone formation},
  series = {Sensors and Actuators B: Chemical. 144 (2010), H. 2},
  journal   = {Sensors and Actuators B: Chemical. 144 (2010), H. 2},
  pages     = {374 -- 379},
  year      = {2010},
  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{YoshinobuEckenPoghossianetal.2001,
  author    = {Yoshinobu, T. and Ecken, H. and Poghossian, Arshak and L{\"u}th, H. and Iwasaki, H. and Sch{\"o}ning, Michael Josef},
  title     = {Alternative sensor materials for light-addressable potentiometric sensors},
  series = {Sensors and Actuators B. 76 (2001), H. 1-3},
  journal   = {Sensors and Actuators B. 76 (2001), H. 1-3},
  isbn      = {0925-4005},
  pages     = {388 -- 392},
  year      = {2001},
  language  = {en}
}
@article{PoghossianAbouzarSakkarietal.2006,
  author    = {Poghossian, Arshak and Abouzar, Maryam H. and Sakkari, M. and Kassab, T. and Han, Y. and Ingebrandt, S. and Offenh{\"a}usser, A. and Sch{\"o}ning, Michael Josef},
  title     = {Field-effect sensors for monitoring the layer-by-layer adsorption of charged macromolecules},
  series = {Sensors and Actuators B: Chemical. 118 (2006), H. 1-2},
  journal   = {Sensors and Actuators B: Chemical. 118 (2006), H. 1-2},
  isbn      = {0925-4005},
  pages     = {163 -- 170},
  year      = {2006},
  language  = {en}
}
@article{KraemerPitaZhouetal.2009,
  author    = {Kr{\"a}mer, Melina and Pita, Marcos and Zhou, Jian and Ornatska, Maryna and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {Coupling of Biocomputing Systems with Electronic Chips: Electronic Interface for Transduction of Biochemical Information},
  series = {Journal of Physical Chemistry C: Nanomaterials and Interfaces. 113 (2009), H. 6},
  journal   = {Journal of Physical Chemistry C: Nanomaterials and Interfaces. 113 (2009), H. 6},
  publisher = {American Cemical Society},
  address   = {Washington, DC},
  isbn      = {1932-7455},
  pages     = {2573 -- 2579},
  year      = {2009},
  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}
}
@inproceedings{NaetherPoghossianPlatenetal.2006,
  author    = {N{\"a}ther, Niko and Poghossian, Arshak and Platen, J. and Yoshinobu, T. and Koudelka-Hep, M. and Sch{\"o}ning, Michael Josef},
  title     = {Multi-parameter sensing of both physical and (bio-)chemical quantities using the same transducer principle},
  series = {Biochemical sensing utilisation of micro- and nanotechnologies : Warsaw, [23rd - 26th] November 2005 / ed. by M. Mascini ...},
  booktitle = {Biochemical sensing utilisation of micro- and nanotechnologies : Warsaw, [23rd - 26th] November 2005 / ed. by M. Mascini ...},
  address   = {Warsaw},
  pages     = {172 -- 181},
  year      = {2006},
  language  = {en}
}
@article{PoghossianJablonskiMolinnusetal.2020,
  author    = {Poghossian, Arshak and Jablonski, Melanie and Molinnus, Denise and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {Field-Effect Sensors for Virus Detection: From Ebola to SARS-CoV-2 and Plant Viral Enhancers},
  series = {Frontiers in Plant Science},
  volume    = {11},
  journal   = {Frontiers in Plant Science},
  number    = {Article 598103},
  publisher = {Frontiers},
  address   = {Lausanne},
  doi       = {10.3389/fpls.2020.598103},
  pages     = {1 -- 14},
  year      = {2020},
  abstract  = {Coronavirus disease 2019 (COVID-19) is a novel human infectious disease provoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, no specific vaccines or drugs against COVID-19 are available. Therefore, early diagnosis and treatment are essential in order to slow the virus spread and to contain the disease outbreak. Hence, new diagnostic tests and devices for virus detection in clinical samples that are faster, more accurate and reliable, easier and cost-efficient than existing ones are needed. Due to the small sizes, fast response time, label-free operation without the need for expensive and time-consuming labeling steps, the possibility of real-time and multiplexed measurements, robustness and portability (point-of-care and on-site testing), biosensors based on semiconductor field-effect devices (FEDs) are one of the most attractive platforms for an electrical detection of charged biomolecules and bioparticles by their intrinsic charge. In this review, recent advances and key developments in the field of label-free detection of viruses (including plant viruses) with various types of FEDs are presented. In recent years, however, certain plant viruses have also attracted additional interest for biosensor layouts: Their repetitive protein subunits arranged at nanometric spacing can be employed for coupling functional molecules. If used as adapters on sensor chip surfaces, they allow an efficient immobilization of analyte-specific recognition and detector elements such as antibodies and enzymes at highest surface densities. The display on plant viral bionanoparticles may also lead to long-time stabilization of sensor molecules upon repeated uses and has the potential to increase sensor performance substantially, compared to conventional layouts. This has been demonstrated in different proof-of-concept biosensor devices. Therefore, richly available plant viral particles, non-pathogenic for animals or humans, might gain novel importance if applied in receptor layers of FEDs. These perspectives are explained and discussed with regard to future detection strategies for COVID-19 and related viral diseases.},
  language  = {en}
}
@article{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}
}
@book{SchoeningPoghossian2018,
  author    = {Sch{\"o}ning, Michael Josef and Poghossian, Arshak},
  title     = {Label-free biosensing: advanced materials, devices and applications},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-75219-8},
  pages     = {xii, 480 Seiten ; Illustrationen, Diagramme},
  year      = {2018},
  language  = {en}
}
@article{JanusAchtsnichtDrinicetal.2023,
  author    = {Janus, Kevin Alexander and Achtsnicht, Stefan and Drinic, Aleksander and Kopp, Alexander and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Transient magnesium-based thin-film temperature sensor on a flexible, bioabsorbable substrate for future medical applications},
  series = {Applied Research},
  journal   = {Applied Research},
  number    = {Accepted manuscript},
  publisher = {Wiley-VCH},
  issn      = {2702-4288 (Print)},
  doi       = {10.1002/appl.202300102},
  pages     = {22 Seiten},
  year      = {2023},
  abstract  = {In this work, the bioabsorbable materials, namely fibroin, polylactide acid (PLA), magnesium and magnesium oxide are investigated for their application as transient, resistive temperature detectors (RTD). For this purpose, a thin-film magnesium-based meander-like electrode is deposited onto a flexible, bioabsorbable substrate (fibroin or PLA) and encapsulated (passivated) by additional magnesium oxide layers on top and below the magnesium-based electrode. The morphology of different layered RTDs is analyzed by scanning electron microscopy. The sensor performance and lifetime of the RTD is characterized both under ambient atmospheric conditions between 30°C and 43°C, and wet tissue-like conditions with a constant temperature regime of 37°C. The latter triggers the degradation process of the magnesium-based layers. The 3-layers RTDs on a PLA substrate could achieve a lifetime of 8.5 h. These sensors also show the best sensor performance under ambient atmospheric conditions with a mean sensitivity of 0.48 Ω/°C ± 0.01 Ω/°C.},
  language  = {en}
}
@article{JanusAchtsnichtTempeletal.2023,
  author    = {Janus, Kevin Alexander and Achtsnicht, Stefan and Tempel, Laura and Drinic, Aleksaner and Kopp, Alexander and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Influence of fibroin membrane composition and curing parameters on the performance of a biodegradable enzymatic biosensor manufactured from Silicon-Free Carbon},
  series = {Physica status solidi : pss. A, Applications and materials science},
  volume    = {220},
  journal   = {Physica status solidi : pss. A, Applications and materials science},
  number    = {22},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6300 (Print)},
  doi       = {10.1002/pssa.202300081},
  pages     = {10 Seiten},
  year      = {2023},
  abstract  = {Herein, fibroin, polylactide (PLA), and carbon are investigated for their suitability as biocompatible and biodegradable materials for amperometric biosensors. For this purpose, screen-printed carbon electrodes on the biodegradable substrates fibroin and PLA are modified with a glucose oxidase membrane and then encapsulated with the biocompatible material Ecoflex. The influence of different curing parameters of the carbon electrodes on the resulting biosensor characteristics is studied. The morphology of the electrodes is investigated by scanning electron microscopy, and the biosensor performance is examined by amperometric measurements of glucose (0.5-10 mM) in phosphate buffer solution, pH 7.4, at an applied potential of 1.2 V versus a Ag/AgCl reference electrode. Instead of Ecoflex, fibroin, PLA, and wound adhesive are tested as alternative encapsulation compounds: a series of swelling tests with different fibroin compositions, PLA, and Ecoflex has been performed before characterizing the most promising candidates by chronoamperometry. Therefore, the carbon electrodes are completely covered with the particular encapsulation material. Chronoamperometric measurements with H2O2 concentrations between 0.5 and 10 mM enable studying the leakage current behavior.},
  language  = {en}
}
@phdthesis{Achtsnicht2020,
  author    = {Achtsnicht, Stefan},
  title     = {Multiplex-Magnetdetektion von superparamagnetischen Beads zur Identifizierung von Trinkwasserkontaminationen},
  doi       = {10.18154/RWTH-2020-12052},
  pages     = {144 Seiten},
  year      = {2020},
  abstract  = {Die qualitative und quantitative Detektion von Zielsubstanzen innerhalb einer w{\"a}ssrigen Probe ist f{\"u}r viele Fragestellungen von Interesse, etwa bei der Detektion von Kontaminationen in Trinkwasser in Krisensituationen. Hierbei ist es nicht nur wichtig, dass Pathogene m{\"o}glichst sensitiv detektiert werden k{\"o}nnen, sondern auch, dass die Analyse schnell erfolgt, um Betroffenen im Katastrophenfall z{\"u}gig sicheres Trinkwasser zu Verf{\"u}gung stellen zu k{\"o}nnen. Da bei einem solchen Szenario nicht von einer in der N{\"a}he befindlichen funktionierenden Laborinfrastruktur ausgegangen werden kann, ist es wichtig, dass die Messung direkt vor Ort erfolgen kann. Im Rahmen dieser Arbeit wurde untersucht, ob eine derartige Schnellanalytik mithilfe von superparamagnetischen Beads (MBs) und der magnetischen Frequenzmischtechnik m{\"o}glich ist. Dabei werden die MBs mit Hilfe von prim{\"a}ren Antik{\"o}rpern an die Zielsubstanz gebunden und mit sekund{\"a}ren Antik{\"o}rpern an die Poren-Oberfl{\"a}che eines Polyethylen-Filters fixiert (Sandwich-Immunoassay). So kann die Quantifizierung der Zielsubstanz auf eine magnetische Messung der immobilisierten MB-Marker zur{\"u}ckgef{\"u}hrt werden. Die magnetische Frequenzmischtechnik basiert auf der Anregung der Probe mit Magnetfeldern zweier verschiedener Frequenzen. Die durch die nichtlineare Magnetisierungsform der superparamagnetischen MBs entstehenden Mischfrequenzen werden typischerweise mithilfe einer zweistufigen Lock-in-Detektion analysiert (analoge Demodulation), die in einem Magnetreader als Handheldger{\"a}t realisiert wurde. Zus{\"a}tzlich zu dieser Technik wurde das Prinzip der direkten Digitalisierung des gesamten Antwortsignals mit anschließender Fourier-Analyse der erzeugten Mischfrequenzen experimentell umgesetzt, um die Amplituden und Phasen mehrerer Mischfrequenzen simultan zu erfassen. Eine M{\"o}glichkeit zur Sensitivit{\"a}tssteigerung ist die magnetische Aufkonzentration, indem vor der magnetischen Analyse eine Separation der MBs aus einem gr{\"o}ßeren Probenvolumen mittels magnetischem Feldgradienten durchgef{\"u}hrt wird. Zur Charakterisierung verschiedener kommerzieller MBs hinsichtlich ihrer magnetischen Separierbarkeit wurde ein Aufbau zur Messung ihrer magnetophoretischen Beweglichkeiten realisiert und ihre Geschwindigkeiten im Gradientenfeld mikroskopisch gemessen.Da eine Probe oftmals nicht nur auf eine einzige Zielsubstanz, sondern simultan auf mehrere verschiedene Pathogene hin untersucht werden soll, wurden verschiedene Ans{\"a}tze entwickelt und getestet, die einen solchen multiparametrischen magnetischen Immunoassay erm{\"o}glichen. Einerseits wurde eine r{\"a}umliche Separation der Bindungsbereiche f{\"u}r verschiedene Zielsubstanzen realisiert, die sequentiell ausgewertet werden k{\"o}nnen. Andererseits wurde die Unterscheidung von verschiedenen Zielsubstanzen anhand der Charakteristika der an sie gebundenen, verschieden funktionalisierten MB-Typen untersucht. F{\"u}r eine solche Unterscheidung wurde zum einen die Anregefrequenz der magnetischen Frequenzmischtechnik w{\"a}hrend einer Messung variiert. Damit konnte gezeigt werden, dass sich verschiedene MB-Sorten anhand der Phase ihrer Frequenzmischsignale voneinander unterscheiden lassen. Weiterhin wurde gezeigt, dass sich der Signalverlauf einer bin{\"a}ren Mischung zweier verschiedener MB-Typen als gradueller {\"U}bergang der Verl{\"a}ufe der beiden reinen MB-L{\"o}sungen ergibt. Eine weitere Analysemethode f{\"u}r einen multiparametrischen Immunoassay besteht darin, ein zus{\"a}tzliches einstellbares statisches magnetisches Offsetfeld zu verwenden. Hierf{\"u}r wurden mehrere Aufbauten auf Basis von Permanent- und Elektromagneten simuliert, konstruiert und charakterisiert. Mithilfe von Simulationen konnte gezeigt werden, dass eine auf diesem Verfahren beruhende Unterscheidung f{\"u}r MBs mit unterschiedlichen magnetischen Partikelmomenten m{\"o}glich ist. Als direkte Anwendung des hier entwickelten Magnetreaders in Zusammenspiel mit der digitalen Demodulation wurde ein magnetischer Assay gegen die B-Untereinheit des Choleratoxins in Trinkwasser mit einem niedrigen Detektionslimit von 0,2 ng/ml demonstriert.},
  language  = {de}
}
@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{MolinnusJanusFangetal.2022,
  author    = {Molinnus, Denise and Janus, Kevin Alexander and Fang, Anyelina C. and Drinic, Aleksander and Achtsnicht, Stefan and K{\"o}pf, Marius and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Thick-film carbon electrode deposited onto a biodegradable fibroin substrate for biosensing applications},
  series = {Physica status solidi (a)},
  volume    = {219},
  journal   = {Physica status solidi (a)},
  number    = {23},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.202200100},
  pages     = {1 -- 9},
  year      = {2022},
  abstract  = {This study addresses a proof-of-concept experiment with a biocompatible screen-printed carbon electrode deposited onto a biocompatible and biodegradable substrate, which is made of fibroin, a protein derived from silk of the Bombyx mori silkworm. To demonstrate the sensor performance, the carbon electrode is functionalized as a glucose biosensor with the enzyme glucose oxidase and encapsulated with a silicone rubber to ensure biocompatibility of the contact wires. The carbon electrode is fabricated by means of thick-film technology including a curing step to solidify the carbon paste. The influence of the curing temperature and curing time on the electrode morphology is analyzed via scanning electron microscopy. The electrochemical characterization of the glucose biosensor is performed by amperometric/voltammetric measurements of different glucose concentrations in phosphate buffer. Herein, systematic studies at applied potentials from 500 to 1200 mV to the carbon working electrode (vs the Ag/AgCl reference electrode) allow to determine the optimal working potential. Additionally, the influence of the curing parameters on the glucose sensitivity is examined over a time period of up to 361 days. The sensor shows a negligible cross-sensitivity toward ascorbic acid, noradrenaline, and adrenaline. The developed biocompatible biosensor is highly promising for future in vivo and epidermal applications.},
  language  = {en}
}
@article{OezsoyluKizildagSchoeningetal.2020,
  author    = {{\"O}zsoylu, Dua and Kizildag, Sefa and Sch{\"o}ning, Michael Josef and Wagner, Torsten},
  title     = {Differential chemical imaging of extracellular acidification within microfluidic channels using a plasma-functionalized light-addressable potentiometric sensor (LAPS)},
  series = {Physics in Medicine},
  volume    = {10},
  journal   = {Physics in Medicine},
  number    = {100030},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2352-4510},
  doi       = {10.1016/j.phmed.2020.100030},
  pages     = {8},
  year      = {2020},
  abstract  = {Extracellular acidification is a basic indicator for alterations in two vital metabolic pathways: glycolysis and cellular respiration. Measuring these alterations by monitoring extracellular acidification using cell-based biosensors such as LAPS plays an important role in studying these pathways whose disorders are associated with numerous diseases including cancer. However, the surface of the biosensors must be specially tailored to ensure high cell compatibility so that cells can represent more in vivo-like behavior, which is critical to gain more realistic in vitro results from the analyses, e.g., drug discovery experiments. In this work, O2 plasma patterning on the LAPS surface is studied to enhance surface features of the sensor chip, e.g., wettability and biofunctionality. The surface treated with O2 plasma for 30 s exhibits enhanced cytocompatibility for adherent CHO-K1 cells, which promotes cell spreading and proliferation. The plasma-modified LAPS chip is then integrated into a microfluidic system, which provides two identical channels to facilitate differential measurements of the extracellular acidification of CHO-K1 cells. To the best of our knowledge, it is the first time that extracellular acidification within microfluidic channels is quantitatively visualized as differential (bio-)chemical images.},
  language  = {en}
}
@article{EngelmannPourshahidiShalabyetal.2022,
  author    = {Engelmann, Ulrich M. and Pourshahidi, Mohammad Ali and Shalaby, Ahmed and Krause, Hans-Joachim},
  title     = {Probing particle size dependency of frequency mixing magnetic detection with dynamic relaxation simulation},
  series = {Journal of Magnetism and Magnetic Materials},
  volume    = {563},
  journal   = {Journal of Magnetism and Magnetic Materials},
  number    = {In progress, Art. No. 169965},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0304-8853},
  doi       = {10.1016/j.jmmm.2022.169965},
  year      = {2022},
  abstract  = {Biomedical applications of magnetic nanoparticles (MNP) fundamentally rely on the particles' magnetic relaxation as a response to an alternating magnetic field. The magnetic relaxation complexly depends on the interplay of MNP magnetic and physical properties with the applied field parameters. It is commonly accepted that particle core size is a major contributor to signal generation in all the above applications, however, most MNP samples comprise broad distribution spanning nm and more. Therefore, precise knowledge of the exact contribution of individual core sizes to signal generation is desired for optimal MNP design generally for each application. Specifically, we present a magnetic relaxation simulation-driven analysis of experimental frequency mixing magnetic detection (FMMD) for biosensing to quantify the contributions of individual core size fractions towards signal generation. Applying our method to two different experimental MNP systems, we found the most dominant contributions from approx. 20 nm sized particles in the two independent MNP systems. Additional comparison between freely suspended and immobilized MNP also reveals insight in the MNP microstructure, allowing to use FMMD for MNP characterization, as well as to further fine-tune its applicability in biosensing.},
  language  = {en}
}
@article{AchtsnichtToedterNiehuesetal.2019,
  author    = {Achtsnicht, Stefan and T{\"o}dter, Julia and Niehues, Julia and Tel{\"o}ken, Matthias and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim and Schr{\"o}per, Florian},
  title     = {3D printed modular immunofiltration columns for frequency mixing-based multiplex magnetic immunodetection},
  series = {Sensors},
  volume    = {19},
  journal   = {Sensors},
  number    = {1},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s19010148},
  pages     = {15 Seiten},
  year      = {2019},
  abstract  = {For performing point-of-care molecular diagnostics, magnetic immunoassays constitute a promising alternative to established enzyme-linked immunosorbent assays (ELISA) because they are fast, robust and sensitive. Simultaneous detection of multiple biomolecular targets from one body fluid sample is desired. The aim of this work is to show that multiplex magnetic immunodetection based on magnetic frequency mixing by means of modular immunofiltration columns prepared for different targets is feasible. By calculations of the magnetic response signal, the required spacing between the modules was determined. Immunofiltration columns were manufactured by 3D printing and antibody immobilization was performed in a batch approach. It was shown experimentally that two different target molecules in a sample solution could be individually detected in a single assaying step with magnetic measurements of the corresponding immobilization filters. The arrangement order of the filters and of a negative control did not influence the results. Thus, a simple and reliable approach to multi-target magnetic immunodetection was demonstrated.},
  language  = {en}
}
@article{AliaziziOezsoyluBakhshiSichanietal.2024,
  author    = {Aliazizi, Fereshteh and {\"O}zsoylu, Dua and Bakhshi Sichani, Soroush and Khorshid, Mehran and Glorieux, Christ and Robbens, Johan and Sch{\"o}ning, Michael Josef and Wagner, Patrick},
  title     = {Development and Calibration of a Microfluidic, Chip-Based Sensor System for Monitoring the Physical Properties of Water Samples in Aquacultures},
  series = {Micromachines},
  volume    = {15},
  journal   = {Micromachines},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2072-666X},
  doi       = {10.3390/mi15060755},
  year      = {2024},
  abstract  = {In this work, we present a compact, bifunctional chip-based sensor setup that measures the temperature and electrical conductivity of water samples, including specimens from rivers and channels, aquaculture, and the Atlantic Ocean. For conductivity measurements, we utilize the impedance amplitude recorded via interdigitated electrode structures at a single triggering frequency. The results are well in line with data obtained using a calibrated reference instrument. The new setup holds for conductivity values spanning almost two orders of magnitude (river versus ocean water) without the need for equivalent circuit modelling. Temperature measurements were performed in four-point geometry with an on-chip platinum RTD (resistance temperature detector) in the temperature range between 2 °C and 40 °C, showing no hysteresis effects between warming and cooling cycles. Although the meander was not shielded against the liquid, the temperature calibration provided equivalent results to low conductive Milli-Q and highly conductive ocean water. The sensor is therefore suitable for inline and online monitoring purposes in recirculating aquaculture systems.},
  language  = {en}
}