*2.1. Materials*

Synthetic monounsaturated phospholipids 1-palmitoyl-2-oleoyl-*sn*-glycero- 3-phosphocholine (16:0-18:1 PC, POPC) and 1-stearoyl-2-oleoyl-*sn*-glycero- 3-phosphocholine (18:0-18:1 PC, SOPC) purchased from Avanti Polar Lipids Inc. (Alabaster, AL, USA) in powder, are used to produce model bilayer systems as described further. Molecular probes for fluorescence spectroscopy measurements, namely 6-dodecanoyl-N, N-dimethyl-2-naphthylamine (Laurdan), 1,6-diphenyl-1,3,5-hexatriene (DPH) and 4-(2-[6-(Dioctylamino)-2-naphthalenyl] ethenyl)-1-(3-sulfopropyl)pyridinium inner salt (di-8-ANEPPS) are purchased from Sigma-Aldrich (Darmstadt, Germany). The same provider supplied chloroform and methanol for lipid solutions, sodium chloride for aqueous solutions as well as D-(+)-Glucose (C6H12O6, BioXtra, ≥99.5%, GC), D-(−)-Fructose (C6H12O6, BioUltra, ≥99.0%, HPLC) and sucrose (C12H22O11, BioXtra, ≥99.5%, GC). Pentane CH3(CH2)3CH<sup>3</sup> and hexane CH3(CH2)4CH<sup>3</sup> of HPLC grade are purchased from Honeywell, Riedel-de Haën (Seelze, Germany). Polydimethylsiloxane (PDMS) is provided by Dow Corning (Midland, MI, USA). All substances used for the preparation of bilayer membranes and vesicle suspensions are utilized as purchased. Aqueous solutions are prepared with bidistilled water from a quartz distiller.
