(592g) Assembly of Amphiphilic Gold Nanoparticles Via Templated Synthesis Using Lipid Structures

In recent years ordered metal nanoparticles have been utilized as the building blocks of anisotropic structures with unique properties difficult or impossible to achieve using isotropic structures. Importantly the size and shape of the ordered structures are essential to their function, yet control over the shape of these structures remains a significant challenge.  Here we report a novel and facile approach for synthesizing ordered structures of gold nanoparticles via templated synthesis using lipid vesicles and tubules. We utilized gold nanoparticles functionalized with mixed monolayers of hydrophilic and hydrophobic ligands which are known to rearrange dynamically on the nanoparticle surface in response to changes in the local environment, particularly at an oil-water interface.  Remarkably, after simply mixing a solution of these amphiphilic nanoparticles with vesicle sheets or tubules, ordered chain-like and ring-like structures were formed.  We propose an assembly mechanism based on (i) the dynamic rearrangement of surface ligands on the gold nanoparticles, and (ii) the preferential association of the hydrophobic ligands on the nanoparticle surface with those in the lipid bilayer.  This mechanism shows great promise as simple yet flexible technique for templated synthesis of novel nanoparticle assemblies.