Lipoamido-PEG4-azide is a PEG-based PROTAC linker can be used in the synthesis of PROTACs.In Vitro: PROTACs contain two different ligands connected by a linker; one is a ligand for an E3 ubiquitin ligase and the other is for the target protein.PROTACs exploit the intracellular ubiquitin-proteasome system to selectively degrade target proteins.Lipoamido-PEG3-azide (compound 12) can be used for the synthesis of surface ligands to prepare hydrophilic and biologically compatible quantum dots