Rhodamine B is used as a tracer dye in water to determine the rate and direction of flow and transport. It is a staining fluorescent dye used in fluorescence microscopy, flow cytometry, fluorescence correlation spectroscopy and ELISA in biotechnology fields.

Bioactivity:

Rhodamine B is a useful fluorochrome for histology due to its fluorescent properties in ultraviolet light. It ejects an electron onto TiO², which is then scavenged by O² forming the O^2- radical anion. This anion ultimately becomes the OH radical. A pH-independent process degrades Rhodamine B in TiO² dispersions containing no dodecylbenzenesulfonate. The compound has been incorporated in a FRET system based on lanthanide-doped nanoparticles for monitoring biological effects. Rhodamine B has also been used as a mitochondrial probe to study the energetic state of multi-drug resistant and sensitive cells where the mitochondrial Rhodamine B concentration was precisely determined with the loss of fluorescence in the presence of MTT Formazan (sc-215399), a fluorescence quencher. In addition, Rhodamine B has been observed to significantly reduce the number of human lip fibroblast cells in culture. Used for staining Negri bodies in tissue.