A silicon-based multi-sensor chip for monitoring of fermentation processes

Abstract

This paper describes the design and characterization of a silicon based sensor chip for monitoring of fermentation processes. The sensor chip consists of three sensors using different transducer principles. A capacitive electrolyte-insulator-semiconductor (EIS) field-effect structure with Ta(2)O(5) as gate material was utilized as pH sensor. An electrolyte conductivity sensor was realized by measuring the impedance between two interdigitated electrodes (IDE). A platinum thermistor was included for temperature measurements. The EIS sensor was integrated into a bioreactor and successfully used for an inline pH measurement. The layout of the IDE has been optimized with respect to a high cell constant and a wide detectable conductivity range. The integrated platinum thermistor allowed for temperature compensation of the electrolyte conductivity measurement. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim