Erythrosine B (free acid)

Erythrosine B is a xanthene-based red fluorescent dye commonly used as biological stain, food colorant (FD&C Red No. 3), as printing ink, dental plaque disclosing agent, and photodynamic agent (photosensitizer) in biochemical and analytical applications. The compound absorbs strongly in the visible spectrum (λmax ~ 524-530nm) and exhibits red to pink fluorescence, making it useful in fluorescence microscopy, protein staining and cell viability assays. Its use as a sensor for spectrofluorimetric and spectrophotometric analysis of amine-based pharmaceuticals renders many advantages because of its availability, low cost, rapid labeling, and high sensitivity. Erythrosine B (EB), is a dye with colorimetric and fluorescent properties, and has been used as an indicator of bacterial viability. EB staining is rapid and works at a single concentration for diverse species of bacteria. The dye is inexpensive and allows for live/dead determination in both colorimetric and fluorescence-based assays for low, medium and high-throughput experimentation. It has been used in the colorimetric and fluorescent determination of protein concentrations in vitro. EB has antiviral activities against Zika and Dengue flaviviruses and inhibits the formation of Aβ fibrils and Aβ-associated cytotoxicity in vitro. Erythrosin B (free acid) is less water-soluble and typically used in organic or buffered aqueous solutions, while the sodium salt is highly water-soluble, making it preferred for aqueous-based biological applications. Spectral Data: λex 524-530nm, λex 545-570nm.