Sulforhodamine B is widely used in biological research as a fluorescent dye for staining cells and tissues. Its strong fluorescence makes it ideal for visualizing cellular structures and tracking cellular processes under a microscope. It is commonly employed in cytotoxicity assays, where it helps measure cell viability by binding to proteins in living cells, allowing researchers to quantify the number of surviving cells after exposure to various compounds. Additionally, it is used in protein labeling and fluorescence microscopy to study protein localization and dynamics within cells. Its stability and bright emission make it a valuable tool in both in vitro and in vivo studies.