TY  - JOUR
A1  - Schusser, Sebastian
A1  - Poghossian, Arshak
A1  - Bäcker, Matthias
A1  - Leinhos, Marcel
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Characterization of biodegradable polymers with capacitive field-effect sensors
JF  - Sensors and actuators B: Chemical
N2  - 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.
KW  - Impedance spectroscopy
KW  - C–V method
KW  - Real-time monitoring
KW  - Poly(d,l-lacticacid)
KW  - (Bio)degradation
KW  - Field-effect sensor
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.snb.2012.07.099
SN  - 0925-4005
N1  - Part of special issue "Selected Papers from the 14th International Meeting on Chemical Sensors"
VL  - 187
SP  - 2
EP  - 7
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Schöning, Michael Josef
A1  - Doll, Theodor
A1  - Wagner, Patrick
T1  - Preface / Doll, Theodor ; Wagner, Patrick ; Schöning, Michael J.
JF  - physica status solidi (a) . 206 (2009), H. 3
Y1  - 2009
SN  - 1862-6319
N1  - Special Issue: Engineering of Functional Interfaces (EnFI 08)
SP  - 389
EP  - 390
ER  - 
TY  - JOUR
A1  - Wagner, Patrick
A1  - Doll, Theodor
A1  - Schöning, Michael Josef
T1  - Engineering of functional interfaces / Patrick Wagner ; Theodor Doll ; Michael J. Schöning (eds.)
JF  - Physica status solidi (A) : Applications and materials science
Y1  - 2014
U6  - http://dx.doi.org/10.1002/pssa.201470241
SN  - 1521-396X (E-Book); 1862-6319 (E-Book); 0031-8965 (Print); 1862-6300 (Print)
VL  - 211
IS  - 6
SP  - 1339
EP  - 1339
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Warmer, Johannes
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
A1  - Kaul, Peter
T1  - Detection of triacetone triperoxide using temperature cycled metal-oxide semiconductor gas sensors
JF  - Physica status solidi (a)
Y1  - 2015
U6  - http://dx.doi.org/10.1002/pssa.201431882
SN  - 1862-6319
VL  - 212
IS  - 6
SP  - 1289
EP  - 1298
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Welden, Rene
A1  - Scheja, Sabrina
A1  - Schöning, Michael Josef
A1  - Wagner, Patrick
A1  - Wagner, Torsten
T1  - Electrochemical Evaluation of Light‐Addressable Electrodes Based on TiO2 for the Integration in Lab‐on‐Chip Systems
JF  - physica status solidi a : applications and materials sciences
N2  - 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.
Y1  - 2018
U6  - http://dx.doi.org/10.1002/pssa.201800150
SN  - 1862-6319
VL  - 215
IS  - 15
SP  - Article number 1800150
PB  - Wiley-VCH
CY  - Weinheim
ER  -