Cy3-PEG-FA (MW 2000) is a fluorescent folate-PEG derivative with excitation/emission wavelengths of ~550 nm/~570 nm. Cy3-PEG-FA (MW 2000) can be readily traced by its intense red fluorescent signal. Cy3-PEG-FA (MW 2000) can be used for cell imaging, folate receptor targeting and detection.