@inproceedings{BohrnMuchaWerneretal.2012, author = {Bohrn, Ulrich and Mucha, Andreas and Werner, Frederik and St{\"u}tz, Evamaria and B{\"a}cker, Matthias and Krumbe, Christoph and Schienle, Meinrad and Fleischer, Maximilian and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {Detection of toxic chromium species in water using cellbased sensor systems}, isbn = {978-3-9813484-2-2}, doi = {10.5162/IMCS2012/P2.1.14}, pages = {1364 -- 1367}, year = {2012}, language = {en} } @article{BohrnMuchaWerneretal.2013, author = {Bohrn, Ulrich and Mucha, Andreas and Werner, Frederik and Trattner, Barbara and B{\"a}cker, Matthias and Krumbe, Christoph and Schienle, Meinrad and St{\"u}tz, Evamaria and Schmitt-Landsiedel, Doris and Fleischer, Maximilian and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {A critical comparison of cell-based sensor systems for the detection of Cr (VI) in aquatic environment}, series = {Sensors and actuators. B: Chemical}, volume = {Vol. 182}, journal = {Sensors and actuators. B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-3077 (E-Journal); 0925-4005 (Print)}, pages = {58 -- 65}, year = {2013}, language = {en} } @article{MiyamotoHayashiSakamotoetal.2017, author = {Miyamoto, Ko-ichiro and Hayashi, Kosuke and Sakamoto, Azuma and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {A high-Q resonance-mode measurement of EIS capacitive sensor by elimination of series resistance}, series = {Sensor and Actuators B: Chemical}, volume = {248}, journal = {Sensor and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2017.03.002}, pages = {1006 -- 1010}, year = {2017}, abstract = {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.}, language = {en} } @article{MiyamotoSekiSutoetal.2018, author = {Miyamoto, Koichiro and Seki, Kosuke and Suto, Takeyuki and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers}, series = {Sensor and Actuators B: Chemical}, volume = {273}, journal = {Sensor and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2018.07.016}, pages = {1328 -- 1333}, year = {2018}, abstract = {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.}, language = {en} } @article{PoghossianWernerBuniatyanetal.2017, author = {Poghossian, Arshak and Werner, Frederik and Buniatyan, V. V. and Wagner, Torsten and Miamoto, K. and Yoshinobu, T. and Sch{\"o}ning, Michael Josef}, title = {Towards addressability of light-addressable potentiometric sensors: Shunting effect of non-illuminated region and cross-talk}, series = {Sensor and Actuators B: Chemical}, journal = {Sensor and Actuators B: Chemical}, number = {244}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2017.01.047}, pages = {1071 -- 1079}, year = {2017}, abstract = {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.}, language = {en} } @article{SiqueiraWernerBaeckeretal.2009, author = {Siqueira, Jose R. and Werner, Frederik and B{\"a}cker, Matthias and Poghossian, Arshak and Zucolotto, Valtencir and Oliveira, Osvaldo N. Jr. and Sch{\"o}ning, Michael Josef}, title = {Layer-by-Layer Assembly of Carbon Nanotubes Incorporated in Light-Addressable Potentiometric Sensors}, series = {Journal of Physical Chemistry C. 113 (2009), H. 33}, journal = {Journal of Physical Chemistry C. 113 (2009), H. 33}, publisher = {American Chemical Society}, address = {Washington, DC}, isbn = {1932-7455}, pages = {14765 -- 14770}, year = {2009}, language = {en} } @inproceedings{TakenagaHerreraWerneretal.2013, author = {Takenaga, Shoko and Herrera, Cony F. and Werner, Frederik and Biselli, Manfred and Schnitzler, Thomas and Sch{\"o}ning, Michael Josef and {\"O}hlschl{\"a}ger, Peter and Wagner, Torsten}, title = {Detection of the metabolic activity of cells by differential measurements based on a single light-addressable potentiometric sensor chip}, 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 = {63 -- 67}, year = {2013}, language = {en} } @inproceedings{TakenagaWernerSawadaetal.2012, author = {Takenaga, Shoko and Werner, Frederik and Sawada, Kazuaki and Sch{\"o}ning, Michael Josef}, title = {Comparison of label-free ACh image sensors based on CCD and LAPS}, isbn = {978-3-9813484-2-2}, doi = {10.5162/IMCS2012/4.2.6}, pages = {356 -- 359}, year = {2012}, language = {en} } @article{WagnerMiyamotoWerneretal.2011, author = {Wagner, Torsten and Miyamoto, K. and Werner, Frederik and Sch{\"o}ning, Michael Josef and Yoshinobu, T.}, title = {Flexible electrochemical imaging with "zoom-in" functionality by using a new type of light-addressable potentiometric sensor}, publisher = {IEEE}, address = {New York}, pages = {2133 -- 2135}, year = {2011}, language = {en} } @article{WagnerVornholtWerneretal.2016, author = {Wagner, Torsten and Vornholt, Wolfgang and Werner, Frederik and Yoshinobu, Tatsuo and Miyamoto, Ko-Ichiro and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Light-addressable potentiometric sensor (LAPS) combined with magnetic beads for pharmaceutical screening}, series = {Physics in medicine}, volume = {2016}, journal = {Physics in medicine}, number = {1}, issn = {2352-4510}, doi = {10.1016/j.phmed.2016.03.001}, pages = {2 -- 7}, year = {2016}, abstract = {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.}, language = {en} } @article{WagnerWernerMiyamotoetal.2009, author = {Wagner, Torsten and Werner, Frederik and Miyamoto, K. and Sch{\"o}ning, Michael Josef and Yoshinobu, T.}, title = {A high-density multi-point LAPS set-up using a VCSEL array and FPGA control}, series = {Procedia Chemistry. 1 (2009), H. 1}, journal = {Procedia Chemistry. 1 (2009), H. 1}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {1876-6196}, pages = {1483 -- 1486}, year = {2009}, language = {en} } @article{WagnerWernerMiyamotoetal.2010, author = {Wagner, Torsten and Werner, Frederik and Miyamoto, Ko-ichiro and Ackermann, Hans-Josef and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef}, title = {FPGA-based LAPS device for the flexible design of sensing sites on functional interfaces}, series = {Physica Status Solidi (A). 207 (2010), H. 4}, journal = {Physica Status Solidi (A). 207 (2010), H. 4}, isbn = {1862-6300}, pages = {844 -- 849}, year = {2010}, language = {en} } @article{WagnerWernerMiyamotoetal.2012, author = {Wagner, Torsten and Werner, Frederik and Miyamoto, Ko-Ichiro and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Development and characterisation of a compact light-addressable potentiometric sensor (LAPS) based on the digital light processing (DLP) technology for flexible chemical imaging}, series = {Sensors and Actuators B: Chemical}, volume = {170}, journal = {Sensors and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2010.12.003}, pages = {34 -- 39}, year = {2012}, abstract = {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.}, language = {en} } @article{WagnerWernerMiyamotoetal.2011, author = {Wagner, Torsten and Werner, Frederik and Miyamoto, Ko-Ichiro and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {A high-density multi-point LAPS set-up using a VCSEL array and FPGA control}, series = {Sensors and Actuators B: Chemical. 154 (2011), H. 2}, journal = {Sensors and Actuators B: Chemical. 154 (2011), H. 2}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {1873-3077}, pages = {124 -- 128}, year = {2011}, language = {en} } @phdthesis{Werner2014, author = {Werner, Frederik}, title = {Development of light-addressable potentiometric sensor systems and their applications in biotechnological environments}, pages = {XI, 149 S.}, year = {2014}, language = {en} } @article{WernerGroebelKrumbeetal.2012, author = {Werner, Frederik and Groebel, Simone and Krumbe, Christoph and Wagner, Torsten and Selmer, Thorsten and Yoshinobu, Tatsuo and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Nutrient concentration-sensitive microorganism-based biosensor}, 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.201100801}, pages = {900 -- 904}, year = {2012}, language = {en} } @article{WernerGroebelSchuhmacheretal.2009, author = {Werner, Frederik and Groebel, Simone and Schuhmacher, K. and Spelthahn, Heiko and Wagner, Torsten and Selmer, Thorsten and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Bestimmung der metabolischen Aktivit{\"a}t von Mikroorganismen w{\"a}hrend des Biogasbildungsprozesses}, 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 = {201 -- 204}, year = {2009}, language = {de} } @article{WernerGroebelWagneretal.2011, author = {Werner, Frederik and Groebel, Simone and Wagner, Torsten and Yoshinobu, Tatsuo and Selmer, Thorsten and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {{\"U}berwachung der metabolischen Aktivit{\"a}t von Mikroorganismen zur Kontrolle des biologischen Prozesses im Biogasfermenter}, series = {Biogas 2011 : Energietr{\"a}ger der Zukunft ; 6. Fachtagung, Fachtagung Braunschweig, 08. und 09. Juni 2011 / VDI Energie und Umwelt}, journal = {Biogas 2011 : Energietr{\"a}ger der Zukunft ; 6. Fachtagung, Fachtagung Braunschweig, 08. und 09. Juni 2011 / VDI Energie und Umwelt}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092121-1}, pages = {285 -- 286}, year = {2011}, language = {de} } @article{WernerKrumbeSchumacheretal.2011, author = {Werner, Frederik and Krumbe, Christoph and Schumacher, Katharina and Groebel, Simone and Spelthahn, Heiko and Stellberg, Michael and Wagner, Torsten and Yoshinobu, Tatsuo and Selmer, Thorsten and Keusgen, Michael and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor}, series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, journal = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, publisher = {Wiley}, address = {Weinheim}, isbn = {1862-6319}, pages = {1340 -- 1344}, year = {2011}, language = {en} } @article{WernerMiyamotoWagneretal.2017, author = {Werner, Frederik and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Lateral resolution enhancement of pulse-driven light-addressable potentiometric sensor}, series = {Sensor and Actuators B: Chemical}, volume = {248}, journal = {Sensor and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2017.02.057}, pages = {961 -- 965}, year = {2017}, abstract = {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.}, language = {en} }