N-(m-PEG4)-N'-(DBCO-PEG4)-Cy5 is a Cy5 labeled fluorescent PEG linker containinig DBCO group, which reacts with azide-bearing compounds or biomolecules to form a stable triazole linkage without copper catalyst. DBCO-activated fluorescein dye will be an ideal alternative to copper intolerant applications. The hydrophilic PEG spacer increases solubility in aqueous media.
