Peptide directed growth of gold films

The unique properties of peptides have led to their use in diverse applications in medicine and nanotechnology. In order to demonstrate their utility as multifunctional, selective, adhesion layers in electronic devices, we demonstrate here peptide mediated synthesis approach for the formation of continuous gold films on a silicon-oxide substrate. This is done using a dual affinity peptide (DAP), engineered to specifically bind to the substrate at one end, and nucleate the growth of gold at the other end. The resulting film is comprised of disk shaped crystalline gold nanoparticles (NPs) with a ratio of 3-4 gold atoms per peptide. Charge transfer between the NPs and the peptide results in positive charging of the NPs, with about 23% of the gold atoms, presumably located at the surface of the NPs, interacting strongly with the peptide side chains. The resistance of the film decreases during its growth, reaching a value of 14 kΩ □^-1 upon the formation of a continuous film. Finally the ability to define pattern of the films on the surface is demonstrated using the peptide as an ink in a micro-contact printing process for the formation of a template pattern on which the gold film is grown. Taking into account the diversity of peptides that can be designed this work demonstrates the promises of the use of DAPs as adhesive templates in the fabrication of devices for diverse applications.