This special green-fluorescent dye (6-FAM picolyl azide)^[1] enables advanced click reaction kinetics due to the usage of a picolyl-azide. This structure can complex copper and, therefore, the dye is already connected to its catalyst for the efficient click reaction. One benefit is that reducing copper concentration allows click reaction with sensitive reactants. Picolyl azides enhance the reaction kinetics so much that it is possible to have a picolyl structure that reacts selectively with an alkyne even when other azides are present.^[2]

This enables among other things the usage of less amount of copper in the click reaction mixture without any effect on the great reaction efficiency achieving the same reaction yields. This effect can be crucial e.g. when copper sensitive enzyme or biomolecules shall be labeled. Once attached to a biomolecule via click chemistry (CuAAC, copper catalyzed alkyne-azide cycloaddition) fluorescence microscopy detection can be performed similar to standard dyes. Due to the spectral properties the 6-FAM picolyl dye can be used as AF488 alternative and FITC alternative.

LITERATURE

[1] BONCAT-FACS-Seq reveals the active fraction of a biocrust community undergoing a wet-up event. Frontiers in Microbiology, 2023, 14, 1176751.

https://doi.org/10.3389/fmicb.2023.1176751

[2] Efficient Tandem Copper‐Catalyzed Click Synthesis of Multisugar‐Modified Oligonucleotides. Angewandte Chemie International Edition, e202405161.

https://doi.org/10.1002/anie.202405161