Self-assembly and immobilization of liposomes in fused-silica capillary by avidin–biotin binding

Small and large unilamellar biotinylated liposomes (SUVs and LUVs) composed of egg phosphatidylcholine and 2 mol% of biotinylated phosphatidylethanolamine were assembled in the presence of avidin at a low concentration (0.05–0.1 mg ml^-1) and simultaneously immobilized in fused-silica capillary tubing. LUV assemblies were immobilized to 21 nmol phospholipid in one capillary, about twice as high as found for the SUV assemblies. Estimated values showed that the capillary inner surface was coated by 4–15 liposome layers. The liposome-coated capillary can be used in capillary electrophoresis for microanalysis of drug-membrane interactions. This avidin–biotin-assembly method may also be applied to immobilize liposomes or proteoliposomes in a high order on a planar solid surface for construction of biomaterials.