Sulfo-Cy7 diacid, SE is widely used in biomedical research for labeling biomolecules due to its near-infrared fluorescence properties. It is particularly effective in in vivo imaging, as its emission wavelength penetrates tissue deeply, allowing for non-invasive tracking of biological processes. This dye is commonly conjugated to antibodies, peptides, or proteins to study cellular interactions, tumor targeting, and drug delivery systems. Its water solubility enhances its utility in biological environments, making it a preferred choice for fluorescence microscopy, flow cytometry, and small animal imaging. Additionally, it is employed in diagnostic applications, such as detecting disease biomarkers, due to its high sensitivity and stability.