Immobilized Enzymes as Catalytically-Active Tools for Nanofabrication

One efficient strategy for creating nanostructures on surfaces is to use the catalytic properties of a surface molecule. This strategy benefits from the amplification and chemical specificity inherent in catalysis. We describe a demonstration of the key step of such a strategy: the surface trapping of a product generated by a nanometer-scale patch of surface-bound enzyme. Nanografting was used to create a approximately 70-nm patch of carboxylic acid groups surrounded by antibiofouling oligio(ethyleneoxide) groups on the surface of a gold ball. A catalytic site was prepared by immobilization of acetylcholine esterase to the carboxylic acid patch, and a product trap was prepared by scratching a small hole in the antibiofouling surface to reveal the gold surface. Two hours after addition of acetylthiocholine, the trap was filled. This demonstrated that the enzyme had catalyzed a reaction and that the product had been used to modify the surface film.