One-Dimensional Alignment of Gold Nanorods and Gold/Silica Core/Shell Nanoparticles by Using Bacterial Flagella as Templates
P. Qiu, C. Mao
University of Oklahoma, US
Keywords: bacterial flagella, gold nanorods, gold nanoparticles
Abstract:Bacterial flagellar filaments can be pictured as protein nanotubes that can be purified from the exterior surface of bacteria. We have successfully used bacterial flagella as a template to align gold nanorods or nanoparticles into an ordered 1D array. We found that the interaction between preformed gold nanorods with the flagellar template resulted in the assembly of the nanorods into a highly ordered 1D array in a head-to-tail format. In this 1D array, the head to tail distance was generally less than 2 nm. Such short spacing can lead to very strong plasmon coupling between neighboring nanorods. By changing experimental conditions, the gold nanorods could also be aligned more densely along the flagella into a string. In order to control the inter-particle distance, gold/silica core/shell nanoparticles were assembled along the flagella. We found that the inter-particle spacing between the gold nanoparticle cores could be tuned by changing the thickness of the silica shell of the core-shell nanoparticles. Our work indicates that flagella can be used to assemble gold nanomaterials into an ordered 1D array with controlled inter-particle spacing, which can find potential applications in wave guiding and polarized surface enhanced Raman scattering (SERS) detection due to the surface plasmon coupling.