Abstract
CE enabled assessing the attachment of hexa‐histidine‐tagged proteins to functionalized phospholipid liposomes. The liposomes were made of 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine, phosphatidyl‐ethanolamine, cholesterol and distearoyl‐glycero‐3‐phosphoethanolamine‐N‐methoxy(polyethylene glycol) in a molar ratio of 29:26:40:5. The unilamellar vesicles, which had an average diameter of 170 nm, were labelled by inclusion of FITC‐dextran for fluorescence detection. CE was carried out in poly(vinyl alcohol) (PVA)‐coated capillaries at 25°C with a BGE consisting of Tris‐HCl (50 mM, pH 8.0). For conjugation of the liposomes with the proteins (soluble synthetic receptor fragments with molecular mass of 60 and 70 kDa, respectively), Ni^2+^ was implanted into the vesicle surface by an anchor lipid containing a nitrilotriacetate acid (NTA) group as complexation agent for the metal ions. The difference in surface charge enabled the separation of the different species of interest by CE: plain vesicles, vesicles functionalised with Ni‐NTA, vesicle–protein complexes and the species formed upon removal of the Ni‐ions by complexation with EDTA. Loss of the Ni‐ions resulted in the release of the proteins and the reappearance of the plain Ni‐free NTA‐liposome species in the electropherograms.