Selective Noncovalent Adsorption of Protein to Bifunctional Metallic Nanowire Surfaces

Abstract

Metallic nanowires composed of nickel and gold as well as bimetallic nickel−gold nanowires were fabricated via templated electrodeposition in nanoporous alumina membranes. Gold surfaces were functionalized with alkanethiols with terminal hexa(ethylene glycol) groups (EG6), while nickel surfaces were functionalized with palmitic acid, a 16-carbon fatty acid. When exposed to a fluorescently tagged protein, hydrophobic nickel wires exhibited bright fluorescence while EG6-terminated gold wires did not, indicating that the protein did not adhere to the EG6-functionalized nanowires. Nickel−gold nanowires presenting distinct segments of alkyl and EG6 surfaces were also exposed to the fluorescent protein. Intense fluorescence was only observed on the nickel segment of these wires, demonstrating that proteins selectively adsorbed to one portion of these multicomponent nanostructures.