Sulfo-Cy7.5dicarboxylic acid is a derivative of Cyanine 7.5 (Cy7.5) dye that contains both carboxylic acid and sulfonate (磺酸根) functional groups. The presence of sulfonate ions enhances the compound's water solubility, making it suitable for aqueous solutions. Cy7.5 is a near-infrared fluorescent dye commonly used in biomedical research areas such as biomarking and cell imaging. Sulfo-Cy7.5dicarboxylic acid can be covalently attached to various biomolecules (especially antibodies, proteins, etc.) to track their localization and dynamic changes within biological samples.