TY  - CHAP
A1  - Bohrn, Ulrich
A1  - Mucha, Andreas
A1  - Werner, Frederik
A1  - Stütz, Evamaria
A1  - Bäcker, Matthias
A1  - Krumbe, Christoph
A1  - Schienle, Meinrad
A1  - Fleischer, Maximilian
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Detection of toxic chromium species in water using cellbased sensor systems
Y1  - 2012
SN  - 978-3-9813484-2-2
U6  - http://dx.doi.org/10.5162/IMCS2012/P2.1.14
SP  - 1364
EP  - 1367
ER  - 
TY  - JOUR
A1  - Bohrn, Ulrich
A1  - Mucha, Andreas
A1  - Werner, Frederik
A1  - Trattner, Barbara
A1  - Bäcker, Matthias
A1  - Krumbe, Christoph
A1  - Schienle, Meinrad
A1  - Stütz, Evamaria
A1  - Schmitt-Landsiedel, Doris
A1  - Fleischer, Maximilian
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - A critical comparison of cell-based sensor systems for the detection of Cr (VI) in aquatic environment
JF  - Sensors and actuators. B: Chemical
Y1  - 2013
SN  - 1873-3077 (E-Journal); 0925-4005 (Print)
VL  - Vol. 182
SP  - 58
EP  - 65
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Miyamoto, Ko-ichiro
A1  - Hayashi, Kosuke
A1  - Sakamoto, Azuma
A1  - Werner, Frederik
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - A high-Q resonance-mode measurement of EIS capacitive sensor by elimination of series resistance
JF  - Sensor and Actuators B: Chemical
N2  - An EIS capacitive sensor is a semiconductor-based potentiometric sensor, which is sensitive to the ion concentration or pH value of the solution in contact with the sensing surface. To detect a small change in the ion concentration or pH, a small capacitance change must be detected. Recently, a resonance-mode measurement was proposed, in which an inductor was connected to the EIS capacitive sensor and the resonant frequency was correlated with the pH value. In this study, the Q factor of the resonant circuit was enhanced by canceling the internal resistance of the reference electrode and the internal resistance of the inductor coil with the help of a bypass capacitor and a negative impedance converter, respectively. 1% variation of the signal in the developed system corresponded to a pH change of 3.93 mpH, which was about 1/12 of the conventional method, suggesting a better performance in detection of a small pH change.
KW  - Negative impedance convertor
KW  - Resonance-mode measurement
KW  - Chemical sensor
KW  - EIS capacitive sensor
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.snb.2017.03.002
SN  - 0925-4005
VL  - 248
SP  - 1006
EP  - 1010
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Miyamoto, Koichiro
A1  - Seki, Kosuke
A1  - Suto, Takeyuki
A1  - Werner, Frederik
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers
JF  - Sensor and Actuators B: Chemical
N2  - The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.
Y1  - 2018
U6  - http://dx.doi.org/10.1016/j.snb.2018.07.016
SN  - 0925-4005
VL  - 273
SP  - 1328
EP  - 1333
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Werner, Frederik
A1  - Buniatyan, V. V.
A1  - Wagner, Torsten
A1  - Miamoto, K.
A1  - Yoshinobu, T.
A1  - Schöning, Michael Josef
T1  - Towards addressability of light-addressable potentiometric sensors: Shunting effect of non-illuminated region and cross-talk
JF  - Sensor and Actuators B: Chemical
N2  - The LAPS (light-addressable potentiometric sensor) platform is one of the most attractive approaches for chemical and biological sensing with many applications ranging from pH and ion/analyte concentration measurements up to cell metabolism detection and chemical imaging. However, although it is generally accepted that LAPS measurements are spatially resolved, the light-addressability feature of LAPS devices has not been discussed in detail so far. In this work, an extended electrical equivalent-circuit model of the LAPS has been presented, which takes into account possible cross-talk effects due to the capacitive coupling of the non-illuminated region. A shunting effect of the non-illuminated area on the measured photocurrent and addressability of LAPS devices has been studied. It has been shown, that the measured photocurrent will be determined not only by the local interfacial potential in the illuminated region but also by possible interfacial potential changes in the non-illuminated region, yielding cross-talk effects. These findings were supported by the experimental investigations of a penicillin-sensitive multi-spot LAPS and a metal-insulator-semiconductor LAPS as model systems.
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.snb.2017.01.047
SN  - 0925-4005
IS  - 244
SP  - 1071
EP  - 1079
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Siqueira, Jose R.
A1  - Werner, Frederik
A1  - Bäcker, Matthias
A1  - Poghossian, Arshak
A1  - Zucolotto, Valtencir
A1  - Oliveira, Osvaldo N. Jr.
A1  - Schöning, Michael Josef
T1  - Layer-by-Layer Assembly of Carbon Nanotubes Incorporated in Light-Addressable Potentiometric Sensors
JF  - Journal of Physical Chemistry C. 113 (2009), H. 33
Y1  - 2009
SN  - 1932-7455
SP  - 14765
EP  - 14770
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - CHAP
A1  - Takenaga, Shoko
A1  - Herrera, Cony F.
A1  - Werner, Frederik
A1  - Biselli, Manfred
A1  - Schnitzler, Thomas
A1  - Schöning, Michael Josef
A1  - Öhlschläger, Peter
A1  - Wagner, Torsten
T1  - Detection of the metabolic activity of cells by differential measurements based on a single light-addressable potentiometric sensor chip
T2  - 11. Dresdner Sensor-Symposium : 9.-11.12.2013
Y1  - 2013
SN  - 978-3-9813484-5-3
SP  - 63
EP  - 67
ER  - 
TY  - CHAP
A1  - Takenaga, Shoko
A1  - Werner, Frederik
A1  - Sawada, Kazuaki
A1  - Schöning, Michael Josef
T1  - Comparison of label-free ACh image sensors based on CCD and LAPS
Y1  - 2012
SN  - 978-3-9813484-2-2
U6  - http://dx.doi.org/10.5162/IMCS2012/4.2.6
SP  - 356
EP  - 359
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Miyamoto, K.
A1  - Werner, Frederik
A1  - Schöning, Michael Josef
A1  - Yoshinobu, T.
T1  - Flexible electrochemical imaging with “zoom-in” functionality by using a new type of light-addressable potentiometric sensor
Y1  - 2011
N1  - 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS) , Date: 5-9 June 2011
SP  - 2133
EP  - 2135
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Vornholt, Wolfgang
A1  - Werner, Frederik
A1  - Yoshinobu, Tatsuo
A1  - Miyamoto, Ko-Ichiro
A1  - Keusgen, Michael
A1  - Schöning, Michael Josef
T1  - Light-addressable potentiometric sensor (LAPS) combined with magnetic beads for pharmaceutical screening
JF  - Physics in medicine
N2  - The light-addressable potentiometric sensor (LAPS) has the unique feature to address different regions of a sensor surface without the need of complex structures. Measurements at different locations on the sensor surface can be performed in a common analyte solution, which distinctly simplifies the fluidic set-up. However, the measurement in a single analyte chamber prevents the application of different drugs or different concentrations of a drug to each measurement spot at the same time as in the case of multi-reservoir-based set-ups. In this work, the authors designed a LAPS-based set-up for cell culture screening that utilises magnetic beads loaded with the endotoxin (lipopolysaccharides, LPS), to generate a spatially distributed gradient of analyte concentration. Different external magnetic fields can be adjusted to move the magnetic beads loaded with a specific drug within the measurement cell. By recording the metabolic activities of a cell layer cultured on top of the LAPS surface, this work shows the possibility to apply different concentrations of a sample along the LAPS measurement spots within a common analyte solution.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.phmed.2016.03.001
SN  - 2352-4510
VL  - 2016
IS  - 1
SP  - 2
EP  - 7
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Werner, Frederik
A1  - Miyamoto, K.
A1  - Schöning, Michael Josef
A1  - Yoshinobu, T.
T1  - A high-density multi-point LAPS set-up using a VCSEL array and FPGA control
JF  - Procedia Chemistry. 1 (2009), H. 1
Y1  - 2009
SN  - 1876-6196
N1  - Proceedings of the Eurosensors XXIII conference ; Eurosensors 23
SP  - 1483
EP  - 1486
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Werner, Frederik
A1  - Miyamoto, Ko-ichiro
A1  - Ackermann, Hans-Josef
A1  - Yoshinobu, Tatsuo
A1  - Schöning, Michael Josef
T1  - FPGA-based LAPS device for the flexible design of sensing sites on functional interfaces
JF  - Physica Status Solidi (A). 207 (2010), H. 4
Y1  - 2010
SN  - 1862-6300
N1  - Special Issue: Engineering of Functional Interfaces EnFI 2009
SP  - 844
EP  - 849
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Werner, Frederik
A1  - Miyamoto, Ko-Ichiro
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Development and characterisation of a compact light-addressable potentiometric sensor (LAPS) based on the digital light processing (DLP) technology for flexible chemical imaging
JF  - Sensors and Actuators B: Chemical
N2  - Chemical imaging systems allow the visualisation of the distribution of chemical species on the sensor surface. This work represents a new flexible approach to read out light-addressable potentiometric sensors (LAPS) with the help of a digital light processing (DLP) set-up. The DLP, known well for video projectors, consists of a mirror-array MEMS device, which allows fast and flexible generation of light patterns. With the help of these light patterns, the sensor surface of the LAPS device can be addressed. The DLP approach has several advantages compared to conventional LAPS set-ups, e.g., the spot size and the shape of the light pointer can be changed easily and no mechanical movement is necessary, which reduces the size of the set-up and increases the stability and speed of the measurement. In addition, the modulation frequency and intensity of the light beam are important parameters of the LAPS set-up. Within this work, the authors will discuss two different ways of light modulation by the DLP set-up, investigate the influence of different modulation frequencies and different light intensities as well as demonstrate the scanning capabilities of the new set-up by pH mapping on the sensor surface.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.snb.2010.12.003
SN  - 0925-4005
N1  - Part of special issue "Eurosensors XXIV, 2010"
VL  - 170
SP  - 34
EP  - 39
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wagner, Torsten
A1  - Werner, Frederik
A1  - Miyamoto, Ko-Ichiro
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - A high-density multi-point LAPS set-up using a VCSEL array and FPGA control
JF  - Sensors and Actuators B: Chemical. 154 (2011), H. 2
Y1  - 2011
SN  - 1873-3077
N1  - EUROSENSORS XXIII
SP  - 124
EP  - 128
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - THES
A1  - Werner, Frederik
T1  - Development of light-addressable potentiometric sensor systems and their applications in biotechnological environments
Y1  - 2014
N1  - Marburg, Univ., Diss., 2014
ER  - 
TY  - JOUR
A1  - Werner, Frederik
A1  - Groebel, Simone
A1  - Krumbe, Christoph
A1  - Wagner, Torsten
A1  - Selmer, Thorsten
A1  - Yoshinobu, Tatsuo
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Nutrient concentration-sensitive microorganism-based biosensor
JF  - Physica Status Solidi (a)
Y1  - 2012
U6  - http://dx.doi.org/10.1002/pssa.201100801
SN  - 1862-6319
VL  - 209
IS  - 5
SP  - 900
EP  - 904
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Werner, Frederik
A1  - Groebel, Simone
A1  - Schuhmacher, K.
A1  - Spelthahn, Heiko
A1  - Wagner, Torsten
A1  - Selmer, Thorsten
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Bestimmung der metabolischen Aktivität von Mikroorganismen während des Biogasbildungsprozesses
JF  - 9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]
Y1  - 2009
SN  - 978-3-941298-44-6
N1  - Dresdner Sensor-Symposium ; (9, 2009, Dresden)
SP  - 201
EP  - 204
PB  - TUDpress
CY  - Dresden
ER  - 
TY  - JOUR
A1  - Werner, Frederik
A1  - Groebel, Simone
A1  - Wagner, Torsten
A1  - Yoshinobu, Tatsuo
A1  - Selmer, Thorsten
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Überwachung der metabolischen Aktivität von Mikroorganismen zur Kontrolle des biologischen Prozesses im Biogasfermenter
JF  - Biogas 2011 : Energieträger der Zukunft ; 6. Fachtagung, Fachtagung Braunschweig, 08. und 09. Juni 2011 / VDI Energie und Umwelt
Y1  - 2011
SN  - 978-3-18-092121-1
N1  - Gesellschaft Energie und Umwelt ; Fachtagung Biogas ; (6 : ; 2011.06.08-09 : ; Braunschweig) ; 	VDI-Berichte ; 2121
SP  - 285
EP  - 286
PB  - VDI-Verl.
CY  - Düsseldorf
ER  - 
TY  - JOUR
A1  - Werner, Frederik
A1  - Krumbe, Christoph
A1  - Schumacher, Katharina
A1  - Groebel, Simone
A1  - Spelthahn, Heiko
A1  - Stellberg, Michael
A1  - Wagner, Torsten
A1  - Yoshinobu, Tatsuo
A1  - Selmer, Thorsten
A1  - Keusgen, Michael
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor
JF  - Physica status solidi (a) : applications and material science. 208 (2011), H. 6
Y1  - 2011
SN  - 1862-6319
SP  - 1340
EP  - 1344
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Werner, Frederik
A1  - Miyamoto, Ko-ichiro
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Lateral resolution enhancement of pulse-driven light-addressable potentiometric sensor
JF  - Sensor and Actuators B: Chemical
N2  - To study chemical and biological processes, spatially resolved determination of the concentrations of one or more analyte species is of distinct interest. With a light-addressable potentiometric sensor (LAPS), chemical images can be created, which visualize the concentration distribution above the sensor plate. One important challenge is to achieve a good lateral resolution in order to detect events that take place in a small and limited region. LAPS utilizes a focused light spot to address the measurement region. By moving this light spot along the semiconductor sensor plate, the concentration distribution can be observed. In this study, we show that utilizing a pulse as light excitation instead of a traditionally used continuously modulated light excitation, the lateral resolution can be improved by a factor of 6 or more.
KW  - Chemical images
KW  - LAPS
KW  - Light-addressable potentiometric sensor
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.snb.2017.02.057
SN  - 0925-4005
VL  - 248
SP  - 961
EP  - 965
PB  - Elsevier
CY  - Amsterdam
ER  -