Sulfo-Cy3 amine is a dye derivative of Cyanine 3 (Cy3) bearing an amine group. The sulfonate ion increases the water solubility of the compound, making it suitable for use in aqueous solutions. Cy3 is a fluorescent dye with a fluorescence spectrum typically in the green to orange wavelength range. The amine functionality of Sulfo-Cy3 amine can react with carboxyl groups to form covalent bonds. Sulfo-Cy3 amine can bind to biological molecules such as proteins and antibodies to track their location and dynamic changes in biological samples.