Fluorescence microscopy enables the study of molecular and morphologic changes in biological specimens with micrometer resolution, providing valuable diagnostic information. Fluorescence microscopy is difficult to use for examination of living tissue, however, because of the need for close association between microscope instrumentation and the imaged tissue, as well as the high concentration of fluorescent dyes required for microscopy.

A disposal dye carrier attached to imaging instruments allows physicians to diagnose tissue without extracting tissue from the body. The carrier consists of a foam-hydrogel composite filled with fluorescent dye. The carrier releases the dye to diffuse throughout the tissue to a depth of 1 mm. Dye release is controlled by the composition of the carrier. The carriers are designed to be used with in vivo imaging instruments which send and receive light to and from the dye to enable live tissue imaging during diagnostic and surgical procedures. The images provide clinicians with a map of the tissue microstructure.