Cy3-PEG-NH2 is a polyethylene glycol (PEG) derivative that incorporates a Cy3 fluorescent dye and an amino group. The Cy3 fluorophore is commonly utilized in applications such as immunolabeling, nucleic acid labeling, fluorescence microscopy, and flow cytometry. Its maximum emission wavelength ranges from approximately 562 to 570 nm. Cy3-PEG-NH2 is applicable for fluorescence imaging, fluorescent tracing, and fluorescent labeling.