Cyanine 3 (Cy3, Figure 1) is a cyanine whose name was introduced in 1989. Cy3 is a fluorescent dye that belongs to the Cyanine family of synthetic polymethine dyes. As cyanines produce a more stable and brighter fluorescence, they may be an advantageous substitute for conventional dyes such as fluorescein and rhodamine. Importantly, Cy3 represents an excellent alternative to NED.
Figure 1. Structure of 5'-Cyanine 3 (R = sequence).
metabion offers the Cy3 modification in its DNA and RNA portfolio: