Deposition of lipid bilayers on OH-density-controlled silicon dioxide surfaces^a)

We investigated the effect of the $SiO2$ surface hydrophilicity on the formation of lipid bilayer membranes using the vesicle fusion method with atomic force microscopy, and applied the results to constructing membrane arrays. We obtained $SiO2$ surfaces with different hydrophilicity by annealing chemically oxidized $SiO2$ surfaces at various temperatures under an $N2$ flow. The membrane formation rate is faster on less hydrophilic surfaces after depositing a 100-nm-filtered vesicle of dimyristoylphosphatidylcholine. Desorption of the surface hydroxyl groups causes a higher affinity between the lipid membrane and the substrate. We also describe a method to fabricate membrane arrays using “chemical patterning.” When the surface hydroxyl groups are locally removed using a focused ion beam (FIB), a bilayer membrane selectively forms on the FIB-patterned region.