Nanoscale patterning in mixed fluorocarbon-hydrocarbon phospholipid bilayers.
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.
Yoder
Nicholas C
NC
Department of Chemistry, Tufts University, Medford, Massachusetts 02155, and Cancer Center, Tufts-New England Medical Center, Boston, Massachusetts 02110, USA.
Kalsani
Venkateshwarlu
V
Schuy
Steffen
S
Vogel
Reiner
R
Janshoff
Andreas
A
Kumar
Krishna
K
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
D005465:Fluorocarbon Polymers; D006838:Hydrocarbons; D008051:Lipid Bilayers; D010743:Phospholipids; D015060:1,2-Dipalmitoylphosphatidylcholine