title: Mapping surface charge density of lipid bilayers by quantitative surface conductivity microscopy.
abstract: Local surface charge density of lipid membranes influences membrane-protein interactions leading to distinct functions in all living cells, and it is a vital parameter in understanding membrane-binding mechanisms, liposome design and drug delivery. Despite the significance, no method has so far been capable of mapping surface charge densities under physiologically relevant conditions. Here, we use a scanning nanopipette setup (scanning ion-conductance microscope) combined with a novel algorithm to investigate the surface conductivity near supported lipid bilayers, and we present a new approach, quantitative surface conductivity microscopy (QSCM), capable of mapping surface charge density with high-quantitative precision and nanoscale resolution. The method is validated through an extensive theoretical analysis of the ionic current at the nanopipette tip, and we demonstrate the capacity of QSCM by mapping the surface charge density of model cationic, anionic and zwitterionic lipids with results accurately matching theoretical values.
authors: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.|Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen Ø DK-2100, Denmark.
authors: Lasse Hyldgaard
authors: LH
authors: Klausen
authors: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors: Thomas
authors: 0000-0003-2608-4284
authors: T
authors: Fuhs
authors: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors: Mingdong
authors: M
authors: Dong
mesh_terms: D000465:Algorithms; D000838:Anions / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008853:Microscopy / Q000295:instrumentation / Q000379:methods*; D008956:Models, Chemical; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D000838:Anions; D002412:Cations; D008051:Lipid Bilayers