It is proposed to develop 1) microprobes suitable for measuring local concentration profiles in immobilized cell layers, 2) a stable, flow-insensitive, steam-sterilizable dissolved oxygen sensor, and 3) microminiature electromechanical valves and pumps by making use of microcircuit fabrication technology. The proposed microprobes for measuring microenvironmental conditions in the immediate vicinity of the immobilized cells are expected to significantly expand the scope of research with immobilized cell processes. The proposed DO sensor will be particularly useful for monitoring dissolved oxygen in mammalian cell cultures and in immobilized cell reactors where sufficient medium flow cannot be provided. The proposed microelectromechanical valves and pumps will be essential for developing sophisticated instruments on a silicon wafer, which can be mass produced for a variety of applications. To carry out the proposed research successfully, a diffusion furnace system capable of oxidation of silicon wafers and chemical vapor deposition is requested.
