title: Visualization and quantification of transmembrane ion transport into giant unilamellar vesicles.
abstract: Transmembrane ion transporters (ionophores) are widely investigated as supramolecular agents with potential for biological activity. Tests are usually performed in synthetic membranes that are assembled into large unilamellar vesicles (LUVs). However transport must be followed through bulk properties of the vesicle suspension, because LUVs are too small for individual study. An alternative approach is described whereby ion transport can be revealed and quantified through direct observation. The method employs giant unilamellar vesicles (GUVs), which are 20-60 μm in diameter and readily imaged by light microscopy. This allows characterization of individual GUVs containing transporter molecules, followed by studies of transport through fluorescence emission from encapsulated indicators. The method provides new levels of certainty and relevance, given that the GUVs are similar in size to living cells. It has been demonstrated using a highly active anion carrier, and should aid the development of compounds for treating channelopathies such as cystic fibrosis.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK).
authors.forename: Hennie
authors.initials: H
authors.lastname: Valkenier
authors.forename: Néstor
authors.initials: N
authors.lastname: López Mora
authors.forename: Alexander
authors.initials: A
authors.lastname: Kros
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Davis
mesh_terms: D001692:Biological Transport; D017136:Ion Transport; D007476:Ionophores / Q000378:metabolism*; D007477:Ions / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D053835:Unilamellar Liposomes / Q000378:metabolism*
chemical_list: D007476:Ionophores; D007477:Ions; D053835:Unilamellar Liposomes
keywords: anions; giant unilamellar vesicles; ion transport; membranes; supramolecular chemistry