Refine
Year of publication
- 2024 (3)
- 2023 (6)
- 2022 (9)
- 2021 (14)
- 2020 (10)
- 2019 (14)
- 2018 (22)
- 2017 (30)
- 2016 (13)
- 2015 (32)
- 2014 (35)
- 2013 (31)
- 2012 (35)
- 2011 (39)
- 2010 (24)
- 2009 (35)
- 2008 (17)
- 2007 (18)
- 2006 (22)
- 2005 (13)
- 2004 (34)
- 2003 (29)
- 2002 (24)
- 2001 (36)
- 2000 (26)
- 1999 (20)
- 1998 (11)
- 1997 (6)
- 1996 (9)
- 1995 (3)
- 1993 (3)
Document Type
- Article (542)
- Conference Proceeding (63)
- Part of a Book (11)
- Book (2)
- Other (2)
- Report (2)
- Patent (1)
Language
- English (551)
- German (71)
- Multiple languages (1)
Keywords
- Biosensor (7)
- Graduiertentagung (5)
- LAPS (4)
- field-effect sensor (4)
- hydrogen peroxide (4)
- Field-effect sensor (3)
- Label-free detection (3)
- Light-addressable potentiometric sensor (3)
- biosensors (3)
- capacitive field-effect sensor (3)
- tobacco mosaic virus (TMV) (3)
- Bacillus atrophaeus (2)
- Calorimetric gas sensor (2)
- Capacitive field-effect sensor (2)
- Graduate symposium (2)
- Hydrogen peroxide (2)
- Raman spectroscopy (2)
- Tobacco mosaic virus (TMV) (2)
- acetoin (2)
- capacitive field-effect sensors (2)
Institute
- Fachbereich Medizintechnik und Technomathematik (603)
- INB - Institut für Nano- und Biotechnologien (526)
- Fachbereich Chemie und Biotechnologie (40)
- FH Aachen (5)
- Nowum-Energy (5)
- Fachbereich Energietechnik (4)
- Institut fuer Angewandte Polymerchemie (3)
- Arbeitsstelle fuer Hochschuldidaktik und Studienberatung (1)
- Fachbereich Elektrotechnik und Informationstechnik (1)
Monitoring the cellular metabolism of bacteria in (bio)fermentation processes is crucial to control and steer them, and to prevent undesired disturbances linked to metabolically inactive microorganisms. In this context, cell-based biosensors can play an important role to improve the quality and increase the yield of such processes. This work describes the simultaneous analysis of the metabolic behavior of three different types of bacteria by means of a differential light-addressable potentiometric sensor (LAPS) set-up. The study includes Lactobacillus brevis, Corynebacterium glutamicum, and Escherichia coli, which are often applied in fermentation processes in bioreactors. Differential measurements were carried out to compensate undesirable influences such as sensor signal drift, and pH value variation during the measurements. Furthermore, calibration curves of the cellular metabolism were established as a function of the glucose concentration or cell number variation with all three model microorganisms. In this context, simultaneous (bio)sensing with the multi-organism LAPS-based set-up can open new possibilities for a cost-effective, rapid detection of the extracellular acidification of bacteria on a single sensor chip. It can be applied to evaluate the metabolic response of bacteria populations in a (bio)fermentation process, for instance, in the biogas fermentation process.
A high-Q resonance-mode measurement of EIS capacitive sensor by elimination of series resistance
(2017)
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.
Macroporous silicon has been etched from n-type Si, using a vertical etching cell where no rear side contact on the silicon wafer is necessary. The resulting macropores have been characterised by means of Scanning Electron Microscopy (SEM). After etching, SiO₂ was thermally grown on the top of the porous silicon as an insulating layer and Si₃N₄ was deposited by means of Low Pressure Chemical Vapour Deposition (LPCVD) as transducer material to fabricate a capacitive pH sensor. In order to prepare porous biosensors, the enzyme penicillinase has been additionally immobilised inside the porous structure. Electrochemical measurements of the pH sensor and the biosensor with an Electrolyte/Insulator/Semiconductor (EIS) structure have been performed in the Capacitance/Voltage (C/V) and Constant capacitance (ConCap) mode.