title: Dynamic force microscopy imaging of native membranes.
abstract: We employed magnetic ACmode atomic force microscopy (MACmode AFM) as a novel dynamic force microscopy method to image surfaces of biological membranes in their native environments. The lateral resolution achieved under optimized imaging conditions was in the nanometer range, even when the sample was only weakly attached to the support. Purple membranes (PM) from Halobacterium salinarum were used as a test standard for topographical imaging. The hexagonal arrangement of the bacteriorhodopsin trimers on the cytoplasmic side of PM was resolved with 1.5nm lateral accuracy, a resolution similar to images obtained in contact and tapping-mode AFM. Human rhinovirus 2 (HRV2) particles were attached to mica surfaces via nonspecific interactions. The capsid structure and 2nm sized protein loops of HRV2 were routinely obtained without any displacement of the virus. Globular and filamentous structures on living and fixed endothelial cells were observed with a resolution of 5-20nm. These examples show that MACmode AFM is a favorable method in studying the topography of soft and weakly attached biological samples with high resolution under physiological conditions.
authors.affiliation: Institute for Biophysics, University of Linz, Altenbergerstr. 69, A-4040, Linz, Austria.
authors.forename: Ferry
authors.initials: F
authors.lastname: Kienberger
authors.forename: Cordula
authors.initials: C
authors.lastname: Stroh
authors.forename: Gerald
authors.initials: G
authors.lastname: Kada
authors.forename: Rosita
authors.initials: R
authors.lastname: Moser
authors.forename: Werner
authors.initials: W
authors.lastname: Baumgartner
authors.forename: Vassili
authors.initials: V
authors.lastname: Pastushenko
authors.forename: Christian
authors.initials: C
authors.lastname: Rankl
authors.forename: Ute
authors.initials: U
authors.lastname: Schmidt
authors.forename: Harald
authors.initials: H
authors.lastname: Müller
authors.forename: Elena
authors.initials: E
authors.lastname: Orlova
authors.forename: Christian
authors.initials: C
authors.lastname: LeGrimellec
authors.forename: Detlev
authors.initials: D
authors.lastname: Drenckhahn
authors.forename: Dieter
authors.initials: D
authors.lastname: Blaas
authors.forename: Peter
authors.initials: P
authors.lastname: Hinterdorfer
mesh_terms: D002213:Capsid / Q000648:ultrastructure; D002462:Cell Membrane / Q000648:ultrastructure*; D002478:Cells, Cultured; D004727:Endothelium / Q000166:cytology; D019617:Halobacterium salinarum / Q000648:ultrastructure; D006801:Humans; D008280:Magnetics; D018625:Microscopy, Atomic Force / Q000379:methods*; D018717:Purple Membrane / Q000648:ultrastructure*; D012229:Rhinovirus / Q000648:ultrastructure