title: Lab-scale fermentation tests of microchip with integrated electrochemical sensors for pH, temperature, dissolved oxygen and viable biomass concentration.
abstract: This article shows the development and testing of a microchip with integrated electrochemical sensors for measurement of pH, temperature, dissolved oxygen and viable biomass concentration under yeast cultivation conditions. Measurements were done both under dynamic batch conditions as well as under prolonged continuous cultivation conditions. The response of the sensors compared well with conventional measurement techniques. The biomass sensor was based on impedance spectroscopy. The results of the biomass sensor matched very well with dry weight measurements and showed a limit of detection of approximately 1 g/L. The dissolved oxygen concentration was monitored amperometrically using an ultra-microelectrode array, which showed an accuracy of approximately 0.2 mg/L and negligible drift. pH was monitored using an ISFET with an accuracy well below 0.1 pH unit. The platinum thin-film temperature resistor followed temperature changes with approximately 0.1 degrees C accuracy. The dimensions of the multi sensor chip are chosen as such that it is compatible with the 96-well plate format.
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands. e.e.krommenhoek@utwente.nl
authors.forename: Erik E
authors.initials: EE
authors.lastname: Krommenhoek
authors.forename: Michiel
authors.initials: M
authors.lastname: van Leeuwen
authors.forename: Han
authors.initials: H
authors.lastname: Gardeniers
authors.forename: Walter M
authors.initials: WM
authors.lastname: van Gulik
authors.forename: Albert
authors.initials: A
authors.lastname: van den Berg
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Li
authors.forename: Marcel
authors.initials: M
authors.lastname: Ottens
authors.forename: Luuk A M
authors.initials: LA
authors.lastname: van der Wielen
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Heijnen
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D049109:Cell Proliferation; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006863:Hydrogen-Ion Concentration; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D010100:Oxygen / Q000378:metabolism*; D010865:Pilot Projects; D018511:Systems Integration; D013696:Temperature; D014159:Transducers
chemical_list: D010100:Oxygen