TY  - JOUR
A1  - Poghossian, Arshak
A1  - Weil, M.
A1  - Cherstvy, A. G.
A1  - Schöning, Michael Josef
T1  - Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices
JF  - Analytical and bioanalytical chemistry
N2  - 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.
Y1  - 2013
U6  - https://doi.org/10.1007/s00216-013-6951-9
SN  - 1432-1130 ; 1618-2642
VL  - 405
IS  - 20
SP  - 6425
EP  - 6436
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Schusser, Sebastian
A1  - Leinhos, Marcel
A1  - Bäcker, Matthias
A1  - Poghossian, Arshak
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Impedance spectroscopy: A tool for real-time in situ monitoring of the degradation of biopolymers
JF  - Physica Status Solidi (A)
N2  - 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.
Y1  - 2013
U6  - https://doi.org/10.1002/pssa.201200941
SN  - 1521-396X ; 0031-8965
VL  - 210
IS  - 5
SP  - 905
EP  - 910
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Huck, Christina
A1  - Schiffels, Johannes
A1  - Herrera, Cony N.
A1  - Schelden, Maximilian
A1  - Selmer, Thorsten
A1  - Poghossian, Arshak
A1  - Baumann, Marcus
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Metabolic responses of Escherichia coli upon glucose pulses captured by a capacitive field-effect sensor
JF  - Physica Status Solidi (A)
N2  - 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.
Y1  - 2013
U6  - https://doi.org/10.1002/pssa.201200900
SN  - 0031-8965
VL  - 210
IS  - 5
SP  - 926
EP  - 931
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Murib, M. S.
A1  - Grinsven, B. van
A1  - Grieten, L.
A1  - Janssens, S. D.
A1  - Vermeeren, V.
A1  - Eersels, K.
A1  - Broeders, J.
A1  - Ameloot, M.
A1  - Michiels, L.
A1  - Ceuninck, W. De
A1  - Haenen, K.
A1  - Schöning, Michael Josef
A1  - Wagner, Patrick
T1  - Electronic monitoring of chemical DNA denaturation on nanocrystalline diamond electrodes with different molarities and flow rates
JF  - Physica Status Solidi (A). Vol. 210 (2013), iss. 5
Y1  - 2013
SN  - 0031-8965
SP  - 911
EP  - 917
PB  - Wiley-VCH
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Schiffels, Johannes
A1  - Pinkenburg, Olaf
A1  - Schelden, Maximilian
A1  - Aboulnaga, El-Hussiny A. A.
A1  - Baumann, Marcus
A1  - Selmer, Thorsten
T1  - An innovative cloning platform enables large-scale production and maturation of an oxygen-tolerant [NiFe]-hydrogenase from cupriavidus necator in Escherichia coli
JF  - PLOS one. 2013
Y1  - 2013
U6  - https://doi.org/10.1371/journal.pone.0068812
SN  - 1932-6203
PB  - Public Library of Science
CY  - San Francisco, California
ER  - 
TY  - JOUR
A1  - Müller, Karsten
A1  - Billmaier, Karl
A1  - Müller, Ernst A.
T1  - Abwasserwärmenutzung
JF  - Wasserwirtschaft, Wassertechnik : wwt. 2013, H. 5
Y1  - 2013
SN  - 1438-5716
SP  - 24
EP  - 26
PB  - Deutscher Fachverlag
CY  - Frankfurt am Main
ER  - 
TY  - JOUR
A1  - Rens, Gavin
A1  - Ferrein, Alexander
T1  - Belief-node condensation for online POMDP algorithms
N2  - Slightly extended version of the paper accepted at the Robotics and Artificial Intelligence Workshop, a special track of IEEE AFRICON-2013, held in Mauritius, 9-12 September 2013
Y1  - 2013
SP  - 1
EP  - 7
PB  - IEEE
CY  - New York
ER  - 
TY  - BOOK
A1  - Bochmann, Sandra
A1  - Ritz, Thomas
T1  - Prototyping tools for mobile applications
Y1  - 2013
SN  - 978-3-943356-45-8
PB  - Steinbeis-Ed.
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Aboulnaga, E. H.
A1  - Pinkenburg, O.
A1  - Schiffels, Johannes
A1  - El-Refai, A.
A1  - Buckel, W.
A1  - Selmer, Thorsten
T1  - Butyrate production in Escherichia coli: Exploitation of an oxygen tolerant bifurcating butyryl-CoA dehydrogenase/electron transferring flavoprotein complex from Clostridium difficile
JF  - Journal of bacteriology. June 14, 2013
Y1  - 2013
SN  - 1098-5530 (E-Journal) ; 0021-9193 (Print)
SP  - Epub ahead of print
ER  - 
TY  - CHAP
A1  - Gebhardt, Andreas
T1  - Entwicklung der 3D-Drucktechnologie und Potenziale für die Anwendung im Mittelstand
T2  - Innovation durch Kooperation : wie der Mittelstand durch Zusammenarbeit mit den Hochschulen seine Wettbewerbsfähigkeit steigert : Festschrift für Prof. Dr. rer. nat. Johannes Gartzen / Thomas Gartzen, Ute Gartzen (Hrsg.)
Y1  - 2013
SN  - 978-3-86359-136-6
SP  - 55
EP  - 59
PB  - Apprimus Verlag
CY  - Aachen
ER  -