Characterization and patterning of bacteriorhodopsin films on Si-based materials

We studied a photosensitive bacterial protein, the bacteriorhodopsin (bR), located in the purple membrane (PM) of the Halobacteritun salinarium. Our main goal is to realize hybrid (organic-inorganic) devices in which the biological part accomplishes complex functions acting as smart material. In order to achieve such goal, many problems need to be solved. Among them, one concerns closely the organic material: it must be patterned. In this work, we succeeded in patterning PM dehydrated films on Si and SiO2 surfaces that keep the protein optical properties. We micro-structured the Si surface by selectively etching some wafer areas using opportunely designed masks. Stripes 0.6-2 mum wide and from 0.2 up to 10 mum deep were fabricated. The PM was deposited, through dipping on the sample in solution, on the structured Si surfaces. The samples were dried structurally characterised.