Azido-PEG4-Azide is a hydrophilic linker with two azide groups. Both can be modified by Click chemistry, either by a copper catalyzed reaction with terminal alkynes, or by a copper-free reaction with cycloalkynes. Azides can also participate in the Staudinger ligation reaction.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.