The work described in this application is aimed at proving the utility of sensors prepared with imaging optical fibers. This project aims to prepare fiber optic sensors for monitoring numerous parameters simultaneously and potentially invasively. The approach offers major advantages over other sensing methods which all employ a distinct sensor for each parameter measured. We plan to apply the method to simultaneous imaging and chemical monitoring. This approach should allow positional and morphological information obtained by imaging through the fibers to be combined with simultaneous chemical analysis of the area of interest. The power of this combined imaging and measuring approach will be demonstrated by applications in both clinical and basic research. Measurements of local values of pH and 02 in precisely localized regions adjacent to living cells and tissues will be accomplished with kidney cell cultures as well as whole organ preparations. The technique involves coupling polymer layers to a coherent imaging fiber bundle of less than several hundred micromoles in diameter. Precise positioning of individual sensing elements on the fiber's distal tip is accomplished via photopolymerization. The signals emanating from the resulting sensor array are detected by means of a Charge Coupled Device (CCD) camera. The combination of imaging fibers and a CCD camera enable spatial information to be preserved. The addition of spatial information to the spectral information in the individual sensing elements provides technical expediency as well as opens the doors for a variety of scientifically important experiments and clinical measurements. This work aims to establish chemical coating techniques for these unique sensors that can be generalized to a wide range of important analytes. In addition the proposal seeks to develop the requisite supporting instrumentation to enable these sensors to be used for biomedical analysis and chemical microscopy.