Effect of Chemical Modification of the Substrate Surface on Supported Lipid Bilayer Formation

We have investigated the effect of chemical state control of the Si substrate surfaces for the formation of lowdefective uniform supported lipid bilayers. To form supported lipid bilayers, we used the vesicle fusion method. In the bilayer formation processes, control of the interfaces between the vesicles and the surfaces is important. To examine the effect of the oxide formation process on Si surfaces, we used SiO2 surfaces prepared by chemical acidtreatment and those by thermal oxidation. SiO2 surfaces are generally hydrophilic. To change the chemical state of the SiO2 surfaces, they were modified with various self-assembled monolayers. These surfaces were immersed in a solution with lipid vesicles suspension, and the lipid vesicles were transformed into planar bilayers. The hydrophilic surface is more suitable for the uniform lipid bilayer formation than the hydrophobic surface. The bilayer coverage on the thermal oxide surface is larger than that on the chemical oxide one. These results indicate that the surface chemical states influence the efficiency of the supported lipid bilayer formation.