@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{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}
}
@inproceedings{PoghossianAbouzarSchoening2012,
  author    = {Poghossian, Arshak and Abouzar, Maryam H. and Sch{\"o}ning, Michael Josef},
  title     = {(Bio-­)chemical sensor array based on nanoplate SOI capacitors},
  series = {Nanoscale Science and Technology (NS\&T´12) : Proceedings Book Humboldt Kolleg ; Tunisia, 17-19 March, 2012},
  booktitle = {Nanoscale Science and Technology (NS\&T´12) : Proceedings Book Humboldt Kolleg ; Tunisia, 17-19 March, 2012},
  editor    = {Abdelghani, Adnane and Sch{\"o}ning, Michael Josef},
  pages     = {31 -- 31},
  year      = {2012},
  language  = {en}
}
@inproceedings{SchusserLeinhosPoghossianetal.2012,
  author    = {Schusser, Sebastian and Leinhos, Marcel and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Biopolymer-degradation monitoring by chip-­based impedance spectroscopy technique},
  series = {Nanoscale Science and Technology (NS\&T´12) : Proceedings Book Humboldt Kolleg ; Tunisia, 17-19 March, 2012},
  booktitle = {Nanoscale Science and Technology (NS\&T´12) : Proceedings Book Humboldt Kolleg ; Tunisia, 17-19 March, 2012},
  editor    = {Abdelghani, Adnane and Sch{\"o}ning, Michael Josef},
  pages     = {47 -- 47},
  year      = {2012},
  language  = {en}
}
@inproceedings{WuPoghossianWerneretal.2013,
  author    = {Wu, Chunsheng and Poghossian, Arshak and Werner, Frederik and Bronder, Thomas and B{\"a}cker, Matthias and Wang, Ping and Sch{\"o}ning, Michael Josef},
  title     = {An application of a scanning light-addressable potentiometric sensor for label-free DNA detection},
  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     = {164 -- 168},
  year      = {2013},
  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{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{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{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{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}
}