Cyanine dyes are members of the polymethine synthetic dye family historically used to increase photographic emulsion sensitivity. Cyanine dyes have versatile applications and are commonly used as fluorescent labels for proteins, nucleic acids, and small molecules. They are particularly suited for biomedical imaging, protein-protein interactions, proteomics, and transcriptomics. Different variants have distinctive spectral properties – for example, Cyanine dye 7 (Cy7) has a strong absorption peak at 747nm while Cyanine dye 5.5 (Cy5.5) has a strong absorption peak at 675nm.
