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BP: Fachverband Biologische Physik
BP 2: Bioimaging and Spectroscopy I
BP 2.9: Vortrag
Montag, 20. März 2017, 12:15–12:30, HÜL 386
Mapping surface charge density of lipid bilayers by quantitative surface conductivity microscopy — Lasse H. Klausen1, •Thomas Fuhs1, 2, and Mingdong Dong1 — 1Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark — 2School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, PR China
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.