9409121 Pizziconi The research proposed in this application is concerned with the feasibility of an immunobiosensor design based upon sensitized mast cells immobilized over the sensing junction of a thin-film thermopile. Antibody on the sensitized mast cells will activate the cell in the presence of antigen, causing a exothermic reaction that will result in very small temperature increases. These temperature increases are detected by the thermopile as the output measure. The project involves microcalometric characterization of cell activation, studies of methods of mast cell immobilization and development of prototype sensors. This research further amplifies a technique using living biological cells as the component in a sensor system by understanding mast cell activation processes. It will also extend bioanalytical sensor research into devices based upon reticuloendothelial cells. ***