@article{DantismTakenagaWagneretal.2016,
  author    = {Dantism, Shahriar and Takenaga, Shoko and Wagner, Patrick and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Determination of the extracellular acidification of Escherichia coli K12 with a multi-​chamber-​based LAPS system},
  series = {Physica status solidi (a)},
  volume    = {213},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1862-6300},
  doi       = {10.1002/pssa.201533043},
  pages     = {1479 -- 1485},
  year      = {2016},
  abstract  = {On-line monitoring of the metabolic activity of microorganisms involved in intermediate stages of biogas production plays an important role to avoid undesirable "down times" during the biogas production. In order to control this process, an on-chip differential measuring system based on the light-addressable potentiometric sensor (LAPS) principle combined with a 3D-printed multi-chamber structure has been realized. As a test microorganism, Escherichia coli K12 (E. coli K12) were used for cell-based measurements. Multi-chamber structures were developed to determine the metabolic activity of E. coli K12 in suspension for a different number of cells, responding to the addition of a constant or variable amount of glucose concentrations, enabling differential and simultaneous measurements.},
  language  = {en}
}
@article{DantismTakenagaWagneretal.2017,
  author    = {Dantism, Shahriar and Takenaga, Shoko and Wagner, Torsten and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Differential imaging of the metabolism of bacteria and eukaryotic cells based on light-addressable potentiometric sensors},
  series = {Electrochimica Acta},
  volume    = {246},
  journal   = {Electrochimica Acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0013-4686},
  doi       = {10.1016/j.electacta.2017.05.196},
  pages     = {234 -- 241},
  year      = {2017},
  abstract  = {A light-addressable potentiometric sensor (LAPS) is a field-effect-based potentiometric sensor with an electrolyte/insulator/semiconductor (EIS) structure, which is able to monitor analyte concentrations of (bio-)chemical species in aqueous solutions in a spatially resolved way. Therefore, it is also an appropriate tool to record 2D-chemical images of concentration variations on the sensor surface. In the present work, two differential, LAPS-based measurement principles are introduced to determine the metabolic activity of Escherichia coli (E. coli) K12 and Chinese hamster ovary (CHO) cells as test microorganisms. Hereby, we focus on i) the determination of the extracellular acidification rate (ΔpH/min) after adding glucose solutions to the cell suspensions; and ii) recording the amplitude increase of the photocurrent (Iph) related to the produced acids from E. coli K12 bacteria and CHO cells on the sensor surface by 2D-chemical imaging. For this purpose, 3D-printed multi-chamber structures were developed and mounted on the planar sensor-chip surface to define four independent compartments, enabling differential measurements with varying cell concentrations. The differential concept allows eliminating unwanted drift effects and, with the four-chamber structures, measurements on the different cell concentrations were performed simultaneously, thus reducing also the overall measuring time.},
  language  = {en}
}