Cy5.5 carboxylic acid is a free non-activated dye and can be used as a non-reactive fluorophore for experiment controls and instrument calibration. It is a non-sulfonated reagent with good solubility in organic solvents and limited aquous solubility.
Appearance: Dark blue solid
ex/em: 680/698 nm (PBS buffer)
Extinction coefficient (ε): 198000 Lmol1cm1
Quantum yield (Φ): 0.20
CY5.5-COOH (Cyanine 5.5 carboxylic acid) is a fluorescent dye, is commonly used in bioimaging. CY5.5-COOH shows narrow absorption spectrum, and high sensitivity and stability[1].
[1] Sijoon Lee, et al. Toxicity and Biodistribution of Fragmented Polypropylene Microplastics in ICR Mice. Int J Mol Sci. 2023 May 9;24(10):8463. DOI:
10.3390/ijms24108463
