Oxygen/Carbon Dioxide Miniature Sensor for Space Bioreactors

Giner, Inc. proposes to develop a miniature electrochemical sensor that detects, in a single sensor, dissolved O2 as well as CO2 for use in space bioreactors. The proposed sensor will be insensitive to membrane fouling and hydrodynamic effects, providing accurate measurements without recalibration. The oxygen detection method will use a novel mode of sensing that is insensitive to fluid flow and membrane fouling. By using a CO2 sensing scheme that involves chemisorbing a ¿reduced-CO2¿ species on a platinum electrode and then stripping by anodically ramping, we can measure CO2 using the same working electrode or a second working electrode within the same sensor. Signal will be linearly related to pCO2, rather than logarithmically related as in conventional (Severinghaus) CO2 detection, leading to greater accuracy. A periodic, steady-state oxygen measurement will indicate the extent of fouling and a correlation will be developed to correct the CO2 measurement. Giner, Inc. is uniquely suited to develop this advanced probe for NASA microgravity bioreactors based on our previous extensive experience with individual O2 and CO2 sensors for clinical applications.