Helix-Coiled Gold Nanowires for Molecular Sensing

Helix-coiled gold nanowires were fabricated by a templating route using unique composite templates consisting of anodic aluminum oxide (AAO) nanotubular membrane and confined mesoporous silica therein. A different degree of confinement energy induces a different degree of helix curvature of confined porous silica nanochannels in an AAO, which works as a hard template for the electrochemical deposition of gold, thereby rationally enabling a different degree of helix curvature of gold nano-replicas. From surface-enhanced Raman scattering experiments, we first found that helix-coiled gold nanowires show more distinctly enhanced molecule sensing efficiency than those from simple smooth gold nanowires, and gold nanowires with the narrower lateral width show more enhanced molecule sensing efficiency than those of thicker width helix nanowires.