Cy7.5 azide a NIR fluorescence dye that ready for the use in Click Chemistry labeling with long-wave infrared fluorescence. For other fluorescent applications, especially requiring low fluorescent background, this labeling reagent was also popular used. As generic Click Chemistry labeling protocol, azide is available as DMSO solution. For biomolecule labeling, the labeling reagent has low aqueous solubility, using of organic co-solvent to dissolve this molecular is necessary for efficient reaction. First, Cyanine dye should be dissolved in organic solvent and then added to a solution of biomolecule in appropriate aqueous buffer.
Cy7.5 azide a sulfonated dye with absorption peaks at 773 and 808 nm, can be the optimal fluorescent probe that should have separate absorption spectra. The changes in the absorption and scattering properties of the tissue are negligible in the range of 750 to 850 nm [1].
Reference:
[1] Osnat Harbater,Israel Gannot. Fluorescent probes concentration estimation in vitro and ex vivo as a model for early detection of Alzheimer’s disease.Jornal of biomedical optics. 2014.19(12).