Cy5.5 Azide

The NIR-fluorescent Cy5.5 azide can be reacted with terminal alkynes via a copper-catalyzed click reaction (CuAAC). It also reacts with strained cyclooctyne via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures.

Cy5.5 Azide is a bright and photostable near-IR probe that spectrally similar to Alexa Fluor® 680, DyLight® 680, and IRDye® 680 dye. The Cy5.5 Azide is water-soluble, hydrophilic dye often a reagent of choice for assay where minimal non-specific binding and exceptional brightness is required. The fluorescence of Cy5.5 Azide is pH insensitive from pH 4 to pH 10 and produces minimal autofluorescence of biological specimens in this region of the spectrum. Fluorescence of this long-wavelength Cyanine dye is not visible to the human eye but is readily detected by most imaging systems.