The problem of low surface area and unknown number of lipid bilayers can be overcome by replacing the macroscopic planar membrane analogue with liposomes. Liposomes are spherical molecular assemblies comprising a lipid bilayer enclosing an aqueous core. Their size and lamellarity can be fairly well controlled . Liposomes are used as drug delivery vehicles thanks to their proven biocompatibility and tuneable properties. Examples of liposome-based drug formulations include Doxil® , or recent mRNA COVID-19 vaccines . Not all molecules are directly suitable for liposomal encapsulation . Too high or too low permeability prevents a drug from being reasonably retained and released from liposomes. Nevertheless, liposomes lend themselves as a tool for studying permeation and measuring permeability . Methods based on detecting a pH change induced by the permeation of a weak base into liposomes , on preloading liposomes with engineered receptors whose fluorescence is quenched by the permeating molecule , or on the so-called immobilized liposome chromatography have been reported.