CONTROL OF PURPLE MEMBRANE ADSORPTION TO A GLASS-SURFACE USING SELF-ASSEMBLED MONOLAYERS

There is a considerable interest in the use of biological materials in electronic device applications. For example the purple membrane, a photoactive biological material, may have an application in artificial retinas. To fabricate devices such as artificial retinas from the purple membrane, a means of patterning the biological material on the substrate surface is needed. We have explored the use of self-assembled monolayers to achieve the control of the adsorption of the purple membrane to a glass surface. By changing the terminal group of the self-assembled monolayer, the affinity of the surface for the purple membrane is controlled. The adsorbed purple membrane films have been examined with x-ray photoelectron spectroscopy and fluorescence microscopy. The x-ray photoelectron spectroscopy data reveal that the purple membrane adsorbs to a clean glass surface in the amount 0.84 mug/cm2. Modifying the glass surface with a fluorocarbon-based self-assembled monolayer reduces the amount of purple membrane adsorbed by a factor of 9.3, to 0.09 mug/cm2. In the future, these results combined with one of the existing methods for patterning self-assembled monolayers, will provide a means of spatially controlling the adsorption of the purple membrane on a substrate. Thus, this work represents an important first step in the patterning of purple membrane structures and devices on a surface.