Incorporation of amphiphilic cyclodextrins into liposomes as artificial receptor units

In this article, we describe the introduction of amphiphilic β-cyclodextrins into liposomes to act as artificial receptor units. Using dynamic light scattering, dye encapsulation, and cryogenic transmission electron microscopy, we show that amphiphilic β-cyclodextrins can be mixed in any proportion with a typical mixture of phospholipids and cholesterol to provide stable, spherical, and unilamellar mixed vesicles. It is also possible to form giant unilamellar vesicles with mixtures of lipids and cyclodextrin. The permeability of the mixed vesicles increases with the percentage of cyclodextrin. The cyclodextrins can act as host molecules for hydrophobic guest molecules, even when they are dispersed at a low percentage in the vesicle membrane. It is shown that mixed vesicles can be decorated with carbohydrate-functionalized guest molecules, with photoresponsive guest molecules, and with dye-functionalized guest molecules. Taken together, it is demonstrated that the host-guest chemistry of amphiphilic cyclodextrins is fully compatible with a liposomal bilayer membrane and the advantages of each can be combined to give superior nanocontainers.