DSPE-PEG(3400) DBCO A89969 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-n-[dibenzocyclooctyl(polyethylene glycol)-3400] (ammonium salt)

 DSPE-PEG(3400) DBCO is a functionalized lipid excipient used in the formulation of liposomes and LNPs (Lipid Nanoparticles). The end of the 3400 PEG spacer is functionalized with a DBCO moiety that reacts selectively with azide-functionalized molecules through strain-promoted azide–alkyne cycloaddition (SPAAC), forming a stable triazole linkage without the need for copper catalyst. This makes DSPE-PEG-DBCO useful for post-formulation conjugation of azide-modified ligands, peptides, sugars, antibodies, fluorophores, or other functional molecules where mild, bioorthogonal reaction conditions are preferred. This molecule is used to introduce targeting, imaging, or surface-modifying groups onto lipid-based particles while retaining the membrane-associating properties of the DSPE anchor. Different PEG chain lengths such as this 3400 may be selected to tune the distance between the lipid surface and the conjugated molecule, as well as to influence formulation behavior, surface accessibility, and particle interactions.