Gold-nanoparticle-functionalized enzymes act as "biocatalytic inks" for the generation of metallic nanowires via dip-pen nanolithography. Deposition of nanoparticle-modified oxidases or a phosphatase followed by development with their respective substrates and metal salts results in nanowires (see figure). This concept may be extended to the generation of other nanostructures via enzyme-catalyzed particle growth.