Incorporation of Calix[6]Arene Macrocycles and (Pseudo)Rotaxanes in Bilayer Membranes: Towards Controllable Artificial Liposomal Channels

The growing interest in the study of membrane-active ion (in particular, anion) transporters motivates the investigation of the mechanisms that underlie the transport process. The interest of the scientific community in this area is largely due to the great importance of transmembrane ion-transport phenomena in many diseases. In this paper we investigated the role of calix[6]arene-based pseudorotaxanes and rotaxanes on transmembrane transport of ions across the bilayer of liposomes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC; diameter 100 nm). We evaluated the effect of these interlocked systems on the properties of the bilayer and on membrane permeability towards chloride ions and 5(6)-carboxyfluorescein. These findings may pave the way for the construction of new generations of pharmacological systems regulating the transport of chloride ions.