| Abstract
| - We have used fluorescence microscopy, fluorescence photobleaching recovery (FPR), and atomic forcemicroscopy (AFM) to investigate the formation of tethered lipid bilayers on plane aluminum oxide or glasssurfaces. The bilayers were assembled with the help of a two-step methodology recently proposed formicroporous templates (Proux-Delrouyre et al. J. Am. Chem. Soc.2001, 123, 8313). The first step consistsof the accumulation of intact biotinylated vesicles (PC + DOPE) on a streptavidin sublayer itself immobilizedon the substrate. The second step, clearly time separated, is the deliberate triggering of bilayer formationwith the help of poly(ethylene glycol) (PEG), a fusion agent of lipidic vesicles. AFM and FPR measurementsconfirm that the vesicles do not spontaneously fuse during the first step provided that the streptavidinsublayer is present on the substrate. On the contrary, the treatment with PEG provokes the fast formationof a continuous lipid bilayer, as attested at the hundred nanometer scale by the AFM images and at thehundred micrometer scale by the lateral diffusion of a fluorescent probe (D = 2.2 × 10-8 cm2 s-1 forNBD-DMPE at 22 °C).
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