Synthesis and Applications of a New Poly(ethylene glycol) Derivative for the Crosslinking of Amines with Thiols

A heterobifunctional crosslinker was synthesized from a diamine derivative of poly(ethylene glycol) (PEG, average molecular weight 800 Da), with the functional groups 2-(pyridyldithio)propionyl (PDP) and N-hydroxysuccinimide ester (NHS). The crosslinker can be used for linkage of two different proteins for which a suitable protocol is presented, explified by crosslinking of two antibodies with 50% yield. In a second application the crosslinker is used to generate immunoliposomes. The NHS group was reacted with an aminolipid for liposome anchorage, and antibodies were bound to the PDP group via disulfide bonds. Loading of liposomes with antibodies was easily adjustable, even down to only a few per liposome. This crosslinker with its particular length appears especially suited for the flexible anchorage of biomembranes, opening new perspectives in membrane research as discussed.