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Article

Nanoscale Patterning in Mixed Fluorocarbon−Hydrocarbon Phospholipid Bilayers

Supporting Info

Nicholas C. Yoder,^† Venkateshwarlu Kalsani,^† Steffen Schuy,^‡ Reiner Vogel,^§ Andreas Janshoff,*^‡ and Krishna Kumar*^†;

Contribution from the Department of Chemistry, Tufts University, Medford, Massachusetts 02155, Institute for Physical Chemistry, University of Mainz, 55128 Mainz, Germany, Institute for Molecular Medicine and Cell Research, University of Freiburg, 79104 Freiburg, Germany, and Cancer Center, Tufts-New England Medical Center, Boston, Massachusetts 02110

J. Am. Chem. Soc., 2007, 129 (29), pp 9037–9043

DOI: 10.1021/ja070950l

Publication Date (Web): June 29, 2007

†

Tufts University.

‡

University of Mainz.

University of Freiburg.

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

Tufts-New England Medical Center.

, krishna.kumar@tufts.edu, ; , janshoff@uni-mainz.de

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 50 nm stripes interspersed between 1 μm 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 T_m 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.