Natural sciences + mathematics Naturwissenschaften ths Prof. Dr. Schöning Michael J. Schöning, Michael J. (Prof. Dr.) Development of light-addressable potentiometric sensor systems and their applications in biotechnological environments LAPS opus:5568 In: Energieträger der Zukunft: Fachtagung Braunschweig, 08. und 09. Juni 2011 / 6. Fachtagung Biogas 2011. VDI Energie und Umwelt. Düsseldorf: VDI-Verlag, 2011, pp. 285–286. u r l: http://d-nb.info/1013435907. Schöning. " Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor " . In: Physica Status Solidi A: Applications and Materials Science 208.6 (2011), pp. 1340–1344. doi: 10.1002/pssa.201001141. Schöning. " Field-programmable gate array based controller for multi spot light- addressable potentiometric sensors with integrated signal correction mode " . In: Electrochimica Acta 56.26 (2011), pp. 9656–9660. doi: 10.1016/j.electacta.2011. 03.012. C. F. Werner, S. Takenaga, H. Taki, K. Sawada, and M. J. Schöning. " Comparison of label-free ACh-imaging sensors based on CCD and LAPS " . In: Sensors and Actuators B: Chemical 177 (2013), pp. 745–752. doi: 10.1016/j.snb.2012.11.012. D. Caras, J. Janata, D. Saupe, and K. Schmitt. " pH-based enzyme potentiometric sensors. Part 1. Theory " . In: Analytical Chemistry 57.9 (1985), pp. 1917–1920. doi: 10.1021/ac00286a027. C. F. Werner, A. Mansour, F.-M. Rateike, S. Schusser, T. Wagner, T. Yoshinobu, M. Keusgen, and M. J. Schöning. " Kompakter Aufbau eines lichtadressierbaren potentiometrischen Sensors mit verfahrbarem Diodenlaser " . German. In: 10. Dresdner Sensor-Symposium: 05.–07. Dezember 2011, Dresden. Ed. by G. Gerlach and A. Schütze. Dresden: TUDpress, 2011, pp. 277–280. doi: 10.5162/10dss2011/14. 3. M. George, W. J. Parak, I. Gerhardt, W. Moritz, F. Kaesen, H. Geiger, I. Eisele, and H. E. Gaub. " Investigation of the spatial resolution of the light-addressable potentiometric sensor " . In: Sensors and Actuators, A: Physical 86.3 (2000), pp. 187– 196. d o i: 10.1016/S0924-4247(00)00455-6. B. Stein, M. George, H. E. Gaub, J. C. Behrends, and W. J. Parak. " Spatially resolved monitoring of cellular metabolic activity with a semiconductor-based biosensor " . In: Biosensors + Bioelectronics 18.1 (2003), pp. 31–41. d o i: 10.1016/ S0956-5663(02)00109-4. B. K. Ahring. " Perspectives for anaerobic digestion " . In: Biomethanation I. Ed. by T. Scheper. Vol. 81. Berlin, Heidelberg: Springer-Verlag, 2003, pp. 1–30. d o i: 10.1007/3-540-45839-5_1. Schöning. " An application of a scanning light-addressable potentiometric sensor for label-free DNA detection " . In: 11. Dresdner Sensor-Symposium 2013. Wunstorf: AMA Service GmbH, 2013, pp. 164–168. d o i: 10.5162/11dss2013/A9. C. F. Werner, S. Groebel, H. Spelthahn, C. Krumbe, T. Wagner, T. Yoshinobu, T. Selmer, M. Keusgen, M. J. Schöning, and S. Schusser. " Array-based light- addressable potentiometric sensor with integrated imaging correction mode " . In: EMNT 2010. Mandelieu la Napoule (France), 2010, p. 067. C. F. Werner, S. Groebel, K. Schumacher, T. Wagner, M. Stellberg, M. E. M. Bau- mann, and M. J. Schöning. " Biosensor to investigate the metabolic activity of acetogen bacteria " . In: Workshop Engineering of Functional Interfaces. Ed. by P. Wagner. Hasselt (Belgium), 2009, p. 45. Ulrich Bohrn (Siemens AG) and Dr. Chunsheng Wu (Zhejiang University and INB) for of Chemical Sensors and Biosensors (INB), Dr. Matthias Bäcker, Sebastian Schusser, Christina Huck, Jan Oberländer, Lars Breuer, Thomas Bronder, Dr. Niko Näther, Dr. S. Takenaga, C. F. Werner, K. Sawada, and M. J. Schöning. " Comparison of label- free ACh image sensors based on CCD and LAPS " . In: IMCS 2012 -The 14th International Meeting on Chemical Sensors. Ed. by R. Moos. Wunstorf (Germany): AMA Service GmbH, 2012, pp. 356–359. d o i: 10.5162/IMCS2012/4.2.6. The members of the laboratory of Chemical Sensors and Biosensors (INB), David Rolka, Heiko Iken, Marcel Leinhos and Stefan Beging for fabricating all the LAPS chips, for their technical discussions and support and for the friendly atmosphere. Prof. Dr. C. F. Werner, S. Groebel, T. Wagner, T. Selmer, T. Yoshinobu, M. E. M. Baumann, M. Keusgen, and M. J. Schöning. " Determination of nutrient concentration by means of a microorganism-based biosensor " . In: Workshop Engineering of Func- tional Interfaces. Linz (Austria), 2011. Schöning. " Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor " . In: physica status solidi (a) 208.6 (2011), pp. 1340–1344. d o i: 10.1002/pssa.201001141. T. Wagner, C. F. Werner, K. Miyamoto, M. J. Schöning, and T. Yoshinobu. " De- velopment and characterisation of a compact light-addressable potentiometric sensor (LAPS) based on the digital light processing (DLP) technology for flexible List of publications chemical imaging " . In: Sensors and Actuators, B: Chemical 170 (2012), pp. 34–39. d o i: 10.1016/j.snb.2010.12.003. German. In: 10. Dresdner Sensor-Symposium: 05.–07. Dezember 2011, Dresden. Ed. by G. Gerlach and A. Schütze. Dresden: TUDpress, 2011, pp. 81–84. d o i: 10. 5162/10dss2011/4.3. Yadvika, Santosh, T. Sreekrishnan, S. Kohli, and V. Rana. " Enhancement of biogas production from solid substrates using different techniques—a review " . In: Biore- source Technology 95.1 (2004), pp. 1–10. d o i: 10.1016/j.biortech.2004.02.010. Japan, for all the assistance during my dissertation and for being a kind of unofficial supervisor. He was in a lot of areas, a role model and a source of inspiration for me. C. F. Werner, S. Groebel, H. Spelthahn, T. Wagner, M. E. M. Baumann, and M. J. Schöning. " Lichtadressierbarer potentiometrischer Sensor zur Überwachung von Biogasanlagen " . German. In: 6. Deutsches BioSensor Symposium. Ed. by G. Urban. Freiburg (Germany), 2009, p. 83. sincere appreciation to: Prof. Dr. Michael J. Schöning for the supervision, for his confidence, for providing the freedom to further develop my skills, for providing me with the opportunity to work with a talented team of researchers and for attending in national and international conferences. It was a pleasure for me to be a part of his team at the FH Aachen, Institute of Nano-and Biotechnologies (INB). Thank you for all the great proof-reading of all manuscripts and thus, the compensating my weaknesses in spelling and grammar. Furthermore, this present thesis would not have been possible without financial support. Hence, I would like to express my gratitude to: The German Federal Ministry of Food, Agriculture and Consumer Protection (BMELV) and the " Fachagentur Nachwachsende Rohstoffe e.V. " (FNR) for financial support of the project " Bio-LAPS " . In: 5. Graduiertentagung der FH Aachen. Ed. by S. Schusser, C. Vaeßen, and M. J. M. Nakao, S. Inoue, T. Yoshinobu, and H. Iwasaki. " High-resolution pH imaging sensor for microscopic observation of microorganisms " . In: Sensors and Actuators B: Chemical 34.1-3 (1996), pp. 234–239. d o i: 10.1016/S0925-4005(96)01903-X. Arshak Poghossian (INB) for the helpful discussions and advices. Benno Schneider (INB) for designing and printing of 3D objects to improve the LAPS set-ups. Thomas Schnitzler (INB) for the opportunity to use the laboratory of cell culture technology and for his professional support. T. Wagner. " Lichtadressierbare potentiometrische Sensoren für den Einsatz in der Pharmazie " . German. PhD thesis. Philipps-Universität Marburg, 2008. D. G. Hafeman, J. W. Parce, and H. M. McConnell. " Light-addressable potentio- metric sensor for biochemical systems " . In: Science 240.4856 (1988), pp. 1182–1185. do i: 10.1126/science.3375810. List of publications List of publications Publications in peer-reviewed journals The students Katharina Schumacher, Ahmed Mansour, Christoph Krumbe and, Marc Reimann for their contributions to the matter of the present dissertation with their own work in the context of their research projects, diploma, bachelor and master theses. Max Krischer for improving the Scanning-LAPS software. Monika Turek and Dr. Maryam Abouzar for the friendly atmosphere and the solidarity during the daily work. C. F. Werner, C. Krumbe, T. Wagner, T. Yoshinobu, T. Selmer, M. Keusgen, and M. J. Schöning. " Measurement of saccharide concentrations using an E. coli cell- based LAPS " . In: Workshop Engineering of Functional Interfaces. Hasselt (Belgium), 2013, p. 44. My friends and my family for their encouragement and support throughout the years. C. F. Werner, C. Krumbe, S. Groebel, H. Spelthahn, T. Wagner, T. Yoshinobu, T. Selmer, M. Keusgen, and M. J. Schöning. " On-line determination of the condition of microorganisms by a light-addressable potentiometric sensor " . In: 3. Graduier- tentagung der FH Aachen. Ed. by N. Schubert, C. Vaeßen, and M. J. Schöning. C. F. Werner, S. Groebel, H. Spelthahn, T. Wagner, M. E. M. Baumann, and M. J. Schöning. " Optimising of the operation of a biogas fermenter by means of a field-effect biosensor based on a light-addressable potentiometric sensor (LAPS) " . In: 2. Graduiertentagung der FH Aachen. Ed. by M. J. Schöning, S. Crummenerl, S. Kowollik, and S. Groebel. Aachen (Germany), 2009, p. 61. u r l: http://nbn- resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-3131. The FH Aachen for financial support in the frame of the promotion of Ph.D. students. The Marubun Research Promotion Foundation (Japan) for the three month scholarship at the Tohoku University. Prof. Dr. Marcus Baumann and Prof. Dr. Thorsten Selmer from INB for their support in the project " Bio-LAPS " . Dr. Simone Groebel (INB) for the cooperation in the project " Bio-LAPS " , for the cultivation of the microorganisms and for providing the technical support and the required material to conduct all the microbiological studies. Prof. Dr. Tatsuo Yoshinobu (Tokoku University) for the close cooperation in the field of LAPS, for the fruitful discussions and for the opportunity to stay three months in Japan and work in his laboratory. Dr. Torsten Wagner (Tokoku University and INB) for his introduction and the long, interesting and fruitful discussions about LAPS, for the opportunity to work in the team " Opto-Switch " , for his support during my stay in Dr. Shoko Takenaga (Toyohashi University and INB) for providing the possibility to work with the CCD-type chemical-imaging sensor, for working together on LAPS experiments and for all the Japanese culture and language skills. Dr. José R. Siqueira, Jr. Prof. Dr. Michael Keusgen (University Marburg) for giving me the opportunity to do a Ph.D. under his supervision, for the proof-reading of the papers and the present thesis as well as for his always uncomplicated and friendly manner. Mrs. Prof. Dr. Petersen and Mr. Prof. Dr. Bünemann from the University Marburg for their attendance in the examination committee. (University of São Paulo and INB), Dr. Ko-ichiro Miyamoto (Tohoku University), Dr. P. Weiland. " Wichtige Messdaten für den Prozessablauf und Stand der Technik in der Praxis " . German. In: Messen, Steuern, Regeln bei der Biogaserzeugung. Vol. 27. Oral and poster presentations T. Yoshinobu, H. Ecken, A. B. M. Ismail, H. Iwasaki, H. Lüth, and M. J. Schöning. " Chemical imaging sensor and its application to biological systems " . In: Elec- trochimica Acta 47.1-2 (2001), pp. 259–263. d o i: 10.1016/S0013-4686(01)00564- 3. Schöning. " High resolution LAPS using amorphous silicon as the semiconductor material " . In: Sensors and Actuators B: Chemical 103.1–2 (2004), pp. 436–441. d o i: 10.1016/j.snb.2004.04.073. M. Schöning, N. Näther, V. Auger, A. Poghossian, and M. Koudelka-Hep. " Minia- turised flow-through cell with integrated capacitive EIS sensor fabricated at wafer level using Si and SU-8 technologies " . In: Sensors and Actuators B: Chemical 108.1–2 (2005), pp. 986–992. d o i: 10.1016/j.snb.2004.12.029. A. Poghossian and M. J. Schöning. " Detecting both physical and (bio-)chemical parameters by means of ISFET devices " . In: Electroanalysis 16.22 (2004), pp. 1863– 1872. d o i: 10.1002/elan.200403074. A. Poghossian, T. Yoshinobu, A. Simonis, H. Ecken, H. Lüth, and M. Schöning. " Penicillin detection by means of field-effect based sensors: EnFET, capacitive EIS sensor or LAPS? " In: Sensors and Actuators, B: Chemical 78.1-3 (2001), pp. 237–242. T. Yoshinobu, H. Iwasaki, Y. Ui, K. Furuichi, Y. Ermolenko, Y. Mourzina, T. Wagner, N. Näther, and M. J. Schöning. " The light-addressable potentiometric sensor for multi-ion sensing and imaging " . In: Methods 37.1 (2005), pp. 94–102. d o i: 10.1016/j.ymeth.2005.05.020. T. Wagner, R. Molina, T. Yoshinobu, J. P. Kloock, M. Biselli, M. Canzoneri, T. Schnitzler, and M. J. Schöning. " Handheld multi-channel LAPS device as a trans- ducer platform for possible biological and chemical multi-sensor applications " . A. Poghossian, S. Ingebrandt, A. Offenhäusser, and M. J. Schöning. " Field-effect devices for detecting cellular signals " . In: Seminars in Cell + Developmental Biology 20.1 (2009), pp. 41–48. d o i: 10.1016/j.semcdb.2009.01.014. Oliveira Jr., and M. J. Schöning. " Layer-by-layer assembly of carbon nanotubes incorporated in light-addressable potentiometric sensors " . In: Journal of Physical Chemistry C 113.33 (2009), pp. 14765–14770. d o i: 10.1021/jp904777t. J. R. Siqueira, R. M. Maki, F. V. Paulovich, C. F. Werner, A. Poghossian, M. C. F. de Oliveira, V. Zucolotto, O. N. Oliveira, and M. J. Schöning. " Use of information visualization methods eliminating cross talk in multiple sensing units investigated for a light-addressable potentiometric sensor " . In: Analytical Chemistry 82.1 (2010), pp. 61–65. d o i: 10.1021/ac9024076. C. F. Werner, S. Groebel, K. Schumacher, H. Spelthahn, T. Wagner, T. Selmer, M. E. M. Baumann, and M. J. Schöning. " Bestimmung der metabolischen Aktivität von Mikroorganismen während des Biogasbildungsprozesses " . German. In: 9. Dresdner Sensor-Symposium: 07.–09. Dezember 2009, Dresden. Ed. by G. Gerlach and P. Hauptmann. Dresden: TUDpress, 2009, pp. 201–204. u r l: http : / / d - nb.info/998316334. T. Wagner, C. F. B. Werner, K. Miyamoto, M. J. Schöning, and T. Yoshinobu. " A high-density multi-point LAPS set-up using a VCSEL array and FPGA control " . T. Wagner, C. F. Werner, K. Miyamoto, H.-J. Ackermann, T. Yoshinobu, and M. J. Schöning. " FPGA-based LAPS device for the flexible design of sensing sites on functional interfaces " . In: Physica Status Solidi A: Applications and Materials Science 207.4 (2010), pp. 844–849. d o i: 10.1002/pssa.200983320. C. F. Werner, T. Wagner, K. Miyamoto, T. Yoshinobu, and M. J. Schöning. " High speed and high resolution chemical imaging based on a new type of OLED- LAPS set-up " . In: Sensors and Actuators B: Chemical 175 (2012), pp. 118–122. d o i: 10.1016/j.snb.2011.12.102. C. F. Werner, S. Groebel, C. Krumbe, T. Wagner, T. Selmer, T. Yoshinobu, M. E. M. Baumann, M. Keusgen, and M. J. Schöning. " Nutrient concentration-sensitive microorganism-based biosensor " . In: Physica Status Solidi A: Applications and Ma- terials Science 209.5 (2012), pp. 900–904. d o i: 10.1002/pssa.201100801. K. Miyamoto, K. Kaneko, A. Matsuo, T. Wagner, S. Kanoh, M. J. Schöning, and T. Yoshinobu. " Miniaturized chemical imaging sensor system using an OLED display panel " . In: Procedia Engineering 5 (2010), pp. 516–519. d o i: 10.1016/j. proeng.2010.09.160. C. F. Werner, T. Wagner, T. Yoshinobu, M. Keusgen, and M. J. Schöning. " Fre- quency behaviour of light-addressable potentiometric sensors " . In: Physica Sta- tus Solidi A: Applications and Materials Science 210.5 (2013), pp. 884–891. d o i: 10.1002/pssa.201200929. T. Wagner, K. Miyamoto, C. F. Werner, M. J. Schöning, and T. Yoshinobu. " Utilising digital micro-mirror device (DMD) as scanning light source for light-addressable potentiometric sensors (LAPS) " . In: Sensor Letters 9.2 (2011), pp. 812–815. d o i: 10.1166/sl.2011.1620. A. Poghossian and M. J. Schöning. " Silicon-based chemical and biological field- effect sensors " . In: Encyclopedia of Sensors. Ed. by C. A. Grimes, E. C. Dickey, and M. V. Pishko. Vol. X. Santa Clarita, California, USA: American Scientific Publishers, 2006, pp. 1–71. S. Takenaga, C. Herrera, C. F. Werner, M. Biselli, T. Schnitzler, M. Schöning, P. Öhlschläger, and T. Wagner. " Detection of the metabolic activity of cells by differential measurements based on a single light-adressable potentiometric sensor chip " . In: 11. Dresdner Sensor-Symposium 2013. Wunstorf: AMA Service GmbH, 2013, pp. 63–67. d o i: 10.5162/11dss2013/3.4. A. M. O'Hara and F. Shanahan. " The gut flora as a forgotten organ " . In: EMBO Rep 7.7 (2006), pp. 688–693. d o i: 10.1038/sj.embor.7400731. J. C. Owicki and J. W. Parce. " Biosensors based on the energy metabolism of living cells: The physical chemistry and cell biology of extracellular acidification " . In: Biosensors + Bioelectronics 7.4 (1992), pp. 255–272. d o i: 10.1016/0956-5663(92) 87004-9. C. F. Werner, H. Spelthahn, M. J. Schöning, C. Krumbe, T. Wagner, T. Yoshinobu, and M. Keusgen. " Neue Ansteuerungselektronik für LAPS-basierte Biosensoren zur gleichzeitigen ortsaufgelösten Messung der pH-Konzentration " . German. In: Sensoren und Messsysteme 2010: Vorträge der 15. ITG-GMA-Fachtagung vom 18. bis 19. Mai 2010 in Nürnberg / ITG-GMA Fachtagung Sensoren und Messsysteme 2010. https://archiv.ub.uni-marburg.de/diss/z2014/0337/cover.png ppn:341194786 micro organisms Stoffwechsel urn:nbn:de:hebis:04-z2014-03370 Die gleichzeitige Analyse von mehreren Analyten und die ortsaufgelöste Messung von Konzentrationsverteilungen mit einem einzelnen Sensorchip ist ein viel diskutiertes Feld in der Sensorentwicklung. Zusammen mit der Miniaturisierung ist dies ein entscheidender Entwicklungsschritt für Anwendungen und Prozesse, welche von Bio- und Chemosensoren profitieren. In Kombination mit biologischen Komponenten zur spezifischen Analytbestimmung, wie Enzymen oder Zellen, sind diese Biosensoren ein interessantes System für biotechnologische, medizinische oder pharmazeutische Applikationen. Ein vielversprechendes Sensorprinzip für diese Aufgaben ist der lichtadressierbare potentiometrische Sensor (LAPS). Ein LAPS ist ein Halbleiter-basierter potentiometrischer Sensor, welcher eine ortsaufgelöste Analytkonzentrationsbestimmung in wässrigen Lösungen erlaubt. Die Ortsauflösung wird mit einem fokussierten Lichtstrahl erreicht. Das Licht erzeugt einen Fotostrom, welcher mit der Analytkonzentration an der Sensoroberfläche im beleuchteten Bereich korreliert. Basierend auf einer früheren Doktorarbeit von Dr. T. Wagner wurden in dieser Promotion LAPS-Aufbauten weiterentwickelt. Des Weiteren wurde die Nutzung dieser LAPS-Aufbauten für biotechnologische, medizinische und pharmazeutische Anwendungen durch die Nutzung von Enzymen und Mikroorganismen demonstriert. In dieser Arbeit wurden zunächst mehrere unterschiedliche LAPS-Aufbauten entwickelt. Der erste LAPS-Aufbau basiert auf einem "Field-programmable Gate Array" (FPGA), welches ein 4x4 Leuchtdioden-Array (LED) ansteuert und somit 16 Messspots auf der Sensoroberfläche definiert. Mit dem FPGA können alle Messspots zum selben Zeitpunkt ausgelesen werden, um z.B. "Chemical Images" der gesamten Sensoroberfläche in nur 200 ms zu erfassen. Mit diesem FPGA-basierte LAPS-Aufbau wurde das Frequenzverhalten von LAPS-Chips untersucht. In einem zweiten LAPS-Aufbau wurde ein kommerziell verfügbares "Organic-LED"-Display (OLED) als Lichtquelle benutzt. Das OLED-Display besitzt 96x64 Pixel mit einer Pixelgröße von 200x200 µm. Um Modulationsfrequenzen im kHz-Bereich zu erhalten, wurde eine neue Ansteuerungsmethode für das OLED-Display entwickelt. Mit dieser Ansteuerungsmethode können "Chemical Images" der gesamten LAPS-Oberfläche in 2,5 min erfasste werden, was ca. 40-mal schneller ist, als mit der herkömmlichen OLED-Ansteuerungsmethode. Da die Ortsauflösung von LAPS nicht allein von der Lichtquelle definiert wird, sondern auch vom LAPS-Chip selbst, wurde die laterale Auflösung der LAPS-Strukturen untersucht. Hierfür wurde ein dritter LAPS-Aufbau entwickelt, welcher eine einzelne Laserdiode auf einer verfahrbaren XY-Einheit benutzt. Durch Charakterisieren von speziell strukturierten LAPS-Chips wurde eine laterale Auflösung in der Größenordnung der OLED-Pixel nachgewiesen. Neben den technologischen Weiterentwicklungen wurde mit dem FPGA-basierten LAPS-Aufbau erstmals der markierungsfreie Nachweis von Konzentrationsverteilungen biologischer Substanzen demonstriert. Mit einer Enzymschicht mit dem Enzym Acetylcholin-Esterase (AChE) wurde der Neurotransmitter Acetylcholin (ACh) nachgewiesen. Das dynamische und statische Ansprechverhalten sowie die Langzeitstabilität wurden charakterisiert und mit einem weiteren, Halbleiter-basierten Sensor, welcher das "Charge-coupled Devices"-Prinzip (CCD) nutzt, unter Verwendung der gleichen Enzymschicht, verglichen. Die Verwendung des FPGA-basierten LAPS-Aufbau als zellbasierter Biosensor wurde mit dem Modelorganismus Escherichia coli gezeigt. Hier wurde die metabolische Aktivität von E. coli untersucht, indem die extrazelluläre Ansäuerung erfasst wurde. Dazu wurde eine Immobilisierungsstrategie entwickelt, bei welcher die Mikroorganismen in Polyacrylamidgel eingebettet wurden. Die Immobilisierung ist in einer Differenzanordnung realisiert worden, welche die Adressierbarkeit des LAPS nutzt, um somit externe Einflüsse wie Sensordrift, Temperaturschwankungen und externe pH-Wertänderungen zu kompensieren. Beim Vergleich der extrazellulären Ansäuerung von immobilisierten E. coli mit E. coli's in Suspension wurden ähnliche Ansäuerungsraten festgestellt, was zeigt, dass die Immobilisierung keinen entscheidenden negativen Einfluss auf die metabolische Aktivität hatte. Weitere Messungen demonstrierten die Sensitivität dieses zellbasierten LAPS-Systems gegenüber unterschiedliche Nährstoffkonzentrationen, was am Beispiel von Glucose ausgeführt wurde. Die Möglichkeit der Erfassung der extrazellulären Ansäuerung von Mikroorganismen sowie die Sensitivität gegenüber Nährstoffkonzentrationen erlaubt es, übergeordnete Effekte wie Toxizität und pharmazeutische Aktivität, von komplexen Messmedien nachzuweisen. Werner, Carl Frederik Werner Carl Frederik English monograph Entwicklung von lichtadressierbaren potentiometrischen Sensor-Systemen und deren Anwendung in biotechnologischen Umgebungen application/pdf metabolic activity Fachbereich Pharmazie biosensor doctoralThesis https://doi.org/10.17192/z2014.0337 2014-05-19 acetylcholine 2014 Philipps-Universität Marburg Pharmazeutische Chemie Chemischer Sensor Bildgebendes Verfahren Publikationsserver der Universitätsbibliothek Marburg Universitätsbibliothek Marburg 2014-06-12 Bakterien Biosensor Acetylcholin 2014-06-12 chemical imaging Biogas The simultaneous analysis of multiple analytes and spatially resolved measurements of concentration distributions with a single sensor chip are an important task in the field of (bio-)chemical sensing. Together with the miniaturisation, this is a promising step forward for applications and processes that profit from (bio-)chemical sensors. In combination with biological recognition elements, like enzymes or cells, these biosensors are becoming an interesting tool for e.g., biotechnological, medical and pharmaceutical applications. One promising sensor principle is the light-addressable potentiometric sensor (LAPS). A LAPS is a semiconductor-based potentiometric sensor that allows determining analyte concentrations of aqueous solutions in a spatially resolved manner. Therefore, it is using a focused light source to address the area of interest. The light that illuminates the local area of the LAPS chip generates a photocurrent that correlates with the local analyte concentration on the sensor surface. Based on the "state of the art", further developments of LAPS set-ups were carried out within this PhD thesis. Furthermore, by utilising enzymes and whole cells, the benefits of these LAPS set-ups for biotechnological, medical and pharmaceutical applications are demonstrated. During the present thesis, three different LAPS set-ups were developed: The first LAPS set-up makes use of a field-programmable gate array (FPGA) to drive a 4x4 light-emitting diode (LED) array that defines 16 measurement spots on the sensor-chip surface. With the help of the FPGA, the driving parameters, like light brightness, modulation amplitude and frequency can be selected individually and all LEDs can be driven concurrently. Thus, a simultaneous readout of all measurement spots is possible and chemical images of the whole sensor surface can be achieved within 200 ms. The FPGA-based LAPS set-up is used to observe the frequency behaviour of LAPS chips. In a second LAPS set-up, a commercially available organic-LED (OLED) display is used as light source. The OLED panel consists of 96x64 pixels with a pixel size of 200x200 µm and thus, an over 16 times higher lateral resolution compared to the IR-LED array. It was demonstrated that chemical images of the whole sensor surface can be obtained in 2.5 min. Since the lateral resolution of LAPS is not only specified by the light source, but also by the LAPS chip itself, the lateral resolution of the LAPS structures is characterised. Therefore, the third LAPS set-up has been developed, which utilises a single laser diode that can be moved by an XY-stage. By scanning a specially patterned LAPS chip, a lateral resolution of the LAPS structures in the range of the pixel size of the OLED display is demonstrated. Label-free imaging of biological phenomena is investigated with the FPGA-based LAPS. With the help of an enzymatic layer with the enzyme acetylcholine esterase (AChE) the detection of the neuronal transmitter acetylcholine (ACh) is demonstrated. The dynamic and static response as well as the long-term stability is characterised and compared with another semiconductor-based chemical imaging sensor based on charge-coupled devices (CCD) using the same enzymatic layer. The usage of the FPGA-based LAPS as whole-cell-based biosensor is studied with the model organism Escherichia coli. Here, the metabolic activity of the E. coli cells is investigated by determining the extracellular acidification. An immobilisation technique for embedding the microorganisms in polyacrylamide gel on the sensor surface has been developed. The immobilisation is realised in an on-chip differential arrangement by making use of the addressability of LAPS. This way, external influences such as sensor drift, temperature changes and external pH changes can be compensated. In a comparative study of the extracellular acidification rate between immobilised E. coli and E. coli that are in suspension, acidification rates in the same order were determined, demonstrating that the immobilisation does not have any influence on the metabolic activity. Further measurements with this cell-based LAPS system underline the sensitivity towards different nutrient concentrations, namely glucose. The ability to observe the extracellular acidification of microorganisms and the sensitively towards nutrient concentrations enables to detect high-order effects, like toxicity or pharmacological activity in complex analytes.