TY  - JOUR
A1  - Dantism, Shahriar
A1  - Röhlen, Desiree
A1  - Wagner, Torsten
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Optimization of Cell-Based Multi-Chamber LAPS Measurements Utilizing FPGA-Controlled Laser-Diode Modules
JF  - physica status solidi a : applications and materials sciences
N2  - A light-addressable potentiometric sensor (LAPS) is a field-effect-based potentiometric device, which detects concentration changes of an analyte solution on the sensor surface in a spatially resolved way. It uses a light source to generate electron–hole pairs inside the semiconductor, which are separated in the depletion region due to an applied bias voltage across the sensor structure and hence, a surface-potential-dependent photocurrent can be read out. However, depending on the beam angle of the light source, scattering effects can occur, which influence the recorded signal in LAPS-based differential measurements. To solve this problem, a novel illumination unit based on a field programmable gate array (FPGA) consisting of 16 small-sized tunable infrared laser-diode modules (LDMs) is developed. Due to the improved focus of the LDMs with a beam angle of only 2 mrad, undesirable scattering effects are minimized. Escherichia coli (E. coli) K12 bacteria are used as a test microorganism to study the extracellular acidification on the sensor surface. Furthermore, a salt bridge chamber is built up and integrated with the LAPS system enabling multi-chamber differential measurements with a single Ag/AgCl reference electrode.
Y1  - 2018
U6  - http://dx.doi.org/10.1002/pssa.201800058
SN  - 1862-6319
VL  - 215
IS  - 15
SP  - Article number 1800058
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Dantism, Shahriar
A1  - Röhlen, Desiree
A1  - Selmer, Thorsten
A1  - Wagner, Torsten
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Quantitative differential monitoring of the metabolic activity of Corynebacterium glutamicum cultures utilizing a light-addressable potentiometric sensor system
JF  - Biosensors and Bioelectronics
Y1  - 2019
U6  - http://dx.doi.org/10.1016/j.bios.2019.111332
VL  - 139
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Dantism, Shahriar
A1  - Röhlen, Desiree
A1  - Dahmen, Markus
A1  - Wagner, Torsten
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - LAPS-based monitoring of metabolic responses of bacterial cultures in a paper fermentation broth
JF  - Sensors and Actuators B: Chemical
N2  - As an alternative renewable energy source, methane production in biogas plants is gaining more and more attention. Biomass in a bioreactor contains different types of microorganisms, which should be considered in terms of process-stability control. Metabolically inactive microorganisms within the fermentation process can lead to undesirable, time-consuming and cost-intensive interventions. Hence, monitoring of the cellular metabolism of bacterial populations in a fermentation broth is crucial to improve the biogas production, operation efficiency, and sustainability. In this work, the extracellular acidification of bacteria in a paper-fermentation broth is monitored after glucose uptake, utilizing a differential light-addressable potentiometric sensor (LAPS) system. The LAPS system is loaded with three different model microorganisms (Escherichia coli, Corynebacterium glutamicum, and Lactobacillus brevis) and the effect of the fermentation broth at different process stages on the metabolism of these bacteria is studied. In this way, different signal patterns related to the metabolic response of microorganisms can be identified. By means of calibration curves after glucose uptake, the overall extracellular acidification of bacterial populations within the fermentation process can be evaluated.
Y1  - 2020
U6  - http://dx.doi.org/10.1016/j.snb.2020.128232
SN  - 0925-4005
VL  - 320
IS  - Art. 128232
PB  - Elsevier
CY  - Amsterdam
ER  -