9522921 Silverman This research is to develop the first in situ glucose and lactate sensors for bioreactor process control. These sensors will be designed to meet reasonable specifications for operational lifetime, resistance to fouling, and maintenance of bioreactor sterility. Multiple layeps of redox enzymes will be electrically connected to electrodes through electron-conducting hydrogels that are permeable to the substrates and the products of the enzymatic reaction. This process of enzyme "wiring" is the basis of the sensors, and allows them to control cell growth in bioreactors by monitoring substrates, products, toxins, etc. The successful completion of this research will improve the efficiency, reduce wastes, and lower manufacturing costs in bioreactors. These sensors will also simplify the monitoring process, add to understanding of control parameters, and begin the expansion of this technology to other analytes.