. Author manuscript; available in PMC: 2023 Jan 1.

Published in final edited form as: Adv Drug Deliv Rev. 2021 Dec 10;180:114079. doi: 10.1016/j.addr.2021.114079

Table 2.

Some representative structural differences between common linear and branched PEG molecules.

	General structure of polyethylene glycol
	Methoxy Linear PEG (mPEG)
	4-Arm branched PEG
	8-Arm branched PEG
	N-hydroxysuccinimide functionalized PEGs can be amine selective binding to specific regions of a protein. These PEGs can be used to conjugate to lysine residues of a protein[139].
	PEG-p-nitrophenyl carbonate bonds to amino groups of a protein. This is less reactive than hydroxysuccinimide and forms the same a carbamate linkage [333].
	PEG aldehyde is used for conjugation to N-terminal α-amino groups of peptides and proteins [333].
	PEG-o- pyridylsulfide is used to selectively bind to thiols [333].
	PEG-chol readily binds to liposomes [147].
	PEG hydrogen bonding with silane groups is used to adhere PEG to silica NPs