Norbornene readily reacts with azide and tetrazine and is usefulness for cell labeling with fluorophore and functional molecules. The azide group can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The PEG spacer increase the solubility of the resulting complex in aqueous media.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.