2-[2-[2-(2-Azidoethoxy)ethoxy]ethoxy]-1-(p-toluenesulfonyl)-ethanol

Azide-PEG4-Tos is a heterofunctional crosslinker containing an azide (N3) group and a tosyl group. The azide group can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The tosyl group is a good leaving group for nucleophilic substitution reactions. PEG spacer increases solubility in aqueous media.