ENZYME CATALYZED METALLIC NANOPARTICLE SYNTHESIS

摘要

The FAD-dependent enzyme glutathione reductase catalyzes the NADPH-dependent synthesis of gold, platinum, and mixed-metal nanoparticles, which are strongly bound to the active site via the redox active cysteine residues. The enzyme stabilizes very small (~5 atom) metallic clusters, and prevents larger clusters from aggregating in the absence of capping ligands. Juxtaposition of the nanoparticle with the FAD cofactor via the active site cysteines enables the maintenance of the nanoparticle at a low potential in the presence of excess NADPH. This allows layered deposition of metals irrespective of redox potential, and the stabilization of low potential metals toward oxidation in aqueous solution. Solid-phase glutathione reductase catalyzed synthesis of gold nanoparticles is demonstrated and proposed as a means to large-scale production of a variety of unique nanoparticle structures.