The lipid bilayers of liposomes are structurally similar to those of biological membranes and are often used as membrane models. Solubilized membrane proteins (transporters, receptors, enzymes, and so on) can be reconstituted into the bilayers (1 –3 ). Interactions between the reconstituted proteins or the lipid bilayers and various substances of biological interest have been studied by several methods, including chromatographic analysis with immobilized proteoliposomes or liposomes as stationary phase (4 –11 ). Lipid monolayers covalently coupled in silica gel beads have also found chromatographic applications (immobilized artificial membrane chromatography) (12 –14 ). Bed reactors with immobilized membrane-bound enzymes in lipid bilayers have been designed (15 ,16 ).
