2.3 - On-Line Monitoring of Glucose, Glutamate and Glutamine During Mammalian Cell Cultivations

Abstract

This chapter elaborates the on-line monitoring of glucose, glutamate, and glutamine during mammalian cell cultivations. Glucose, glutamate, and glutamine sensors were constructed based on rhodinized carbon electrodes. By this approach, the operating potential for detecting enzymatically generated H2O2 could be significantly reduced. Glucose sensors were fabricated by depositing glucose oxidase on to the electrode face. The enzyme layer was subsequently overlaid with a cellulose acetate membrane. Glutamate and glutamine sensors were constructed, based on the immobilization of the appropriate enzyme, using glutaraldehyde. A parallel three cell FIA system was developed for on-line monitoring. Initially, bare metallized electrodes were tested against media samples to ascertain the presence of electrochemically active species, and no significant signal was observed. It is found that when in operation the sample line was aseptically connected to the harvest line of a perfusion culture. Undiluted cell cultivation media was pumped directly from the harvest line, through the FIA system to the enzyme sensors.