SUBSTRATE-MEMBRANE INTERACTIONS - MECHANISMS FOR IMPOSING PATTERNS ONA FLUID BILAYER-MEMBRANE

A variety of new techniques are emerging that require the use of a pat terned substrate to impose micropartitions on a supported fluid bilaye r membrane. The barrier-forming characteristics of aluminum oxide, ind ium-tin oxide (ITO), chrome, and gold patterns on silica substrates ha ve been examined. All four materials form effective barriers to latera l diffusion within the supported membrane; however, two distinctly dif ferent mechanisms were observed. Aluminum oxide inhibits vesicle fusio n, thus restricting membrane formation to the exposed silica surface, in contrast, vesicles will fuse with ITO, chrome, and, to some extent, gold; however, the resulting membrane is effectively immobile over th e time scale of several hours. These materials partition the supported membrane by selectively immobilizing membrane that adsorbs to their s urface. The two mechanisms of membrane partitioning described here pro vide additional flexibility in the design and application of micropatt erned membranes.