N-(azide-PEG3)-N'-(Amine-C3-PEG4)-Cy5 is a PEG analogue containing a cyanine dye with excitation/emission maximum 649/667 nm as well as an azide group, which enables Click Chemistry. The hydrophilic PEG spacer increases solubility in aqueous media. References: Chen X, Zhang X, Wang HY, Chen Z, Wu FG. Subcellular Fate of a Fluorescent Cholesterol-Poly(ethylene glycol) Conjugate: An Excellent Plasma Membrane Imaging Reagent. Langmuir. 2016 Oct 4;32(39):10126-10135. Epub 2016 Sep 21. PubMed PMID: 27597442.

纯度：≥98%