We will develop a laser-based instrument to monitor cell viability through NADH fluorescence when the tissue is illuminated with a pulsed nitrogen laser. Key experiments have already been performed on isolated, perfused rat liver which indicate the feasibility of this approach. The research will be continued in order to determine the optimum operation parameters for the instrument. In addition, a complete instrument design will be made. Phase II will be devoted to further experiments and to construction and initial testing of a prototype instrument.Awardee's statement of the potential commercial applications of the research: After commercialization, the laser-based fluorescence instrument will have applications in both the medical research and clinical environment. The real-time monitoring of cell viability will aid in surgical and post-surgical determination of cell survivability.National Institute of General Medical Sciences (NIGMS)