title: Nanoscale patterning in mixed fluorocarbon-hydrocarbon phospholipid bilayers.
abstract: A growing body of literature suggests that fluorocarbons can direct self-assembly within hydrocarbon environments. We report here the fabrication and characterization of supported lipid bilayers (SLBs) composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and a synthetic, fluorocarbon-functionalized analogue, 1. AFM investigation of these model membranes reveals an intricate, composition-dependent domain structure consisting of approximately 50 nm stripes interspersed between approximately 1 microm sized domains. Although DSC of 1 showed a phase transition near room temperature, DSC of DPPC:1 mixtures exhibited complex phase behavior suggesting domain segregation. Finally, temperature-dependent AFM of DPPC:1 bilayers shows that, while the stripe structures can be melted above the Tm of 1, the stripes and domains result from immiscibility of the hydrocarbon and fluorocarbon lipid gel phases. Fluorination appears to be a promising strategy for chemical self-assembly in two dimensions. In particular, because no modification is made to the lipid headgroups, it may be useful for nanopatterning biologically relevant ligands on bilayers in vitro or in living cells.
authors.affiliation: Department of Chemistry, Tufts University, Medford, Massachusetts 02155, and Cancer Center, Tufts-New England Medical Center, Boston, Massachusetts 02110, USA.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Yoder
authors.forename: Venkateshwarlu
authors.initials: V
authors.lastname: Kalsani
authors.forename: Steffen
authors.initials: S
authors.lastname: Schuy
authors.forename: Reiner
authors.initials: R
authors.lastname: Vogel
authors.forename: Andreas
authors.initials: A
authors.lastname: Janshoff
authors.forename: Krishna
authors.initials: K
authors.lastname: Kumar
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002855:Chromatography, Thin Layer; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D036103:Nanotechnology; D010743:Phospholipids / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D005465:Fluorocarbon Polymers; D006838:Hydrocarbons; D008051:Lipid Bilayers; D010743:Phospholipids; D015060:1,2-Dipalmitoylphosphatidylcholine