Lipopeptides derived from HIV and SIV mimicking the prehairpin intermediate of gp41 on solid supported lipid bilayers.

We present a universal mimetic approach of the prehairpin intermediate of gp41, which represents the active drug target for fusion inhibitors of HIV (human immunodeficiency virus) and SIV (simian immunodeficiency virus) based on membrane anchored lipopeptides. For this purpose, we have in situ coupled terminal cysteine-modified peptides originating from the NHR of SIV and HIV to a maleimide-functionalized DOPC bilayer and monitored the interactions with potential antagonists of the trimer-of-hairpin conformation C34 and T20 peptides by means of atomic force microscopy and ellipsometry. FT-IR analysis in conjugation with CD-spectroscopy of hydrated N36-lipopeptides, incorporated in multilamellar bilayer stacks was employed to investigate peptide conformation prior to antagonist binding.

In situ synthesis of lipopeptides as versatile receptors for the specific binding of nanoparticles and liposomes to solid-supported membranes.

A detailed study of the in situ coupling of small peptides such as CGGH6 (H6) and CGWK8 (K8) to maleimide functionalized phospholipid bilayers is presented. Individually addressable microstructured membranes are employed to unequivocally probe the conjugation. The in situ coupling of peptides via a terminal cysteine moiety to maleimide functionalized phospholipids is shown to be a convenient and versatile way to selectively fabricate peptide-modified phospholipid bilayers serving as specific receptor platforms for functionalized vesicles and nanoparticles.

Structure and thermotropic phase behavior of fluorinated phospholipid bilayers: a combined attenuated total reflection FTIR spectroscopy and imaging ellipsometry study.

Lipid bilayers consisting of lipids with terminally perfluoroalkylated chains have remarkable properties. They exhibit increased stability and phase-separated nanoscale patterns in mixtures with nonfluorinated lipids. In order to understand the bilayer properties that are responsible for this behavior, we have analyzed the structure of solid-supported bilayers composed of 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC) and of a DPPC analogue with 6 terminal perfluorinated methylene units (F6-DPPC).

Phase transition of individually addressable microstructured membranes visualized by imaging ellipsometry.

The phase transition of individually addressable microstructured lipid bilayers was investigated by means of imaging ellipsometry. Microstructured bilayers were created on silicon substrates by micromolding in capillaries, and the thermotropic behavior of various saturated diacyl phosphatidylcholine (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dipentadecoyl-sn-glycero-3-phosphocholine, and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)) bilayers as well as DMPC/cholesterol membranes was determined by measuring the area expansion and thickness of the bilayer as a function of temperature. We found an increase in the main phase transition temperature T(M) of 2-6 degrees C and a substantially reduced cooperativity compared to multilamellar vesicles.