title: Nanoscale mechanical probing of supported lipid bilayers with atomic force microscopy.
abstract: We present theory and experiments for the force-distance curve F(z(0)) of an atomic force microscope (AFM) tip (radius R) indenting a supported fluid bilayer (thickness 2d). For realistic conditions the force is dominated by the area compressibility modulus κ(A) of the bilayer and, to an excellent approximation, given by F=πκ(A)Rz(0)(2)/(2d-z(0))(2). The experimental AFM force curves from coexisting liquid ordered and liquid disordered domains in three-component lipid bilayers are well described by our model, which provides κ(A) in agreement with literature values. The liquid ordered phase has a yieldlike response that we model as due to the breaking of hydrogen bonds.
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom. c.das@leeds.ac.uk
authors.forename: Chinmay
authors.initials: C
authors.lastname: Das
authors.forename: Khizar H
authors.initials: KH
authors.lastname: Sheikh
authors.forename: Peter D
authors.initials: PD
authors.lastname: Olmsted
authors.forename: Simon D
authors.initials: SD
authors.lastname: Connell
mesh_terms: D001696:Biomechanical Phenomena; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D057446:Hydrodynamics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D055595:Mechanical Phenomena; D018625:Microscopy, Atomic Force / Q000379:methods*; D036103:Nanotechnology / Q000379:methods*
chemical_list: D008051:Lipid Bilayers