– Dye 40 is a multifunctional dye used in biological experiments to observe and analyze cell structures, track biomolecules, evaluate cell functions, distinguish cell types, detect biomolecules, study tissue pathology, and monitor microorganisms. Its applications span basic scientific research to clinical diagnostics, as well as traditional fields such as textile dyeing and emerging fields like functional textile processing, food pigments, and dye-sensitized solar cells.