Title :
Monitoring of yeast cell concentration using a micromachined impedance sensor
Author :
Krommenhoek, E.E. ; Gardeniers, J.G.E. ; Bomer, J.G. ; van den Berg, A. ; Li, Xin ; Ottens, M. ; van der Wielen, L.A.M. ; van Dedem, G.W.K. ; van Leeuwen, Matthijs ; van Gulik, W.M. ; Heijnen, J.J.
Author_Institution :
MESA+ Inst. for Nanotechnology, Twente Univ., Enschede, Netherlands
Abstract :
The paper describes the design, modelling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in a Saccharomyces cerevisiae cell culture show that the permittivity of the cell suspension depends linearly on the biomass concentration within the range of 0 to 9 g/l. In order to compensate the measurements for changes in the dielectric properties of the background electrolyte, the use of a three-electrode configuration in combination with a semi-permeable pHEMA membrane was explored. Measurements showed that the impedance of the hydrated pHEMA varies with only the background electrolyte conductivity, and not with the concentration of cells, indicating that pHEMA is suitable for this purpose. The optimal pHEMA membrane thickness was determined using finite element modelling.
Keywords :
biosensors; cellular biophysics; electric impedance; electric sensing devices; ionic conductivity; membranes; micromachining; microsensors; monitoring; permittivity; Saccharomyces cerevisiae cell culture; background electrolyte dielectric properties; biomass concentration; finite element modelling; micromachined impedance sensor; miniaturized cell assay; permittivity; semipermeable membrane; semipermeable pHEMA membrane; three-electrode configuration; viable yeast cell concentration monitoring; Biomass; Biomembranes; Biosensors; Conductivity measurement; Dielectric measurements; Fungi; Impedance; Monitoring; Permittivity measurement; Sensor phenomena and characterization;
Conference_Titel :
Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on
Print_ISBN :
0-7803-8994-8
DOI :
10.1109/SENSOR.2005.1496412
