title: Nanomechanical contrasts of gel and fluid phase supported lipid bilayers.
abstract: Lipid bilayers exhibit structural diversity that contributes to the complex properties of the cell membrane. We use interfacial force microscopy to correlate mechanical properties with the two-dimensional phase behavior of supported lipid bilayers (SLBs). Upon indentation by a 500 nm tungsten tip, a contrast in the mechanical response is observed for gel vs fluid phase SLBs. We measure the yield force and time scale for recovery for these films. Consistent with a gel phase, a DSPC SLB has a relatively high yield force and slow recovery. In the higher mobility fluid phase, a DLPC SLB has a lower yield force and completely recovers within the experimental time scale. Friction measurements offer further contrast between the two SLBs.
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Goertz
authors.forename: B L
authors.initials: BL
authors.lastname: Stottrup
authors.forename: J E
authors.initials: JE
authors.lastname: Houston
authors.forename: X-Y
authors.initials: XY
authors.lastname: Zhu
mesh_terms: D004548:Elasticity; D017276:Friction; D005782:Gels / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D044367:Phase Transition; D010713:Phosphatidylcholines / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties
chemical_list: D005782:Gels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C015153:1,2-dilauroylphosphatidylcholine; C010942:1,2-distearoyllecithin; D012825:Silicon