MICROBIAL SYNTHESIS OF GOLD NANOTRIANGLES USING THE METAL-REDUCING BACTERIUM SHEWANELLA ALGAE

摘要

Microbial synthesis of gold nanotriangles was achieved at room temperature using Fe(III)-reducing bacterium Shewanella algae. Cell extracts prepared by sonicating a cell suspension as well as S. algae cells were capable of reducing 1 mM aqueous Au(III) ions into elemental gold within 10 min when H_2 gas was provided as the electron donor. The reaction time was found to be an important factor in controlling the morphology of biogenic gold particles. At an early stage of reaction, well dispersed spherical gold nanoparticles below 10 nm in size were synthesized, and gold nanotriangles 100 nm in size started to synthesize after 6 h. After 1 day, 60% of the total nanoparticle population using the cell extracts was due to gold nanotriangles, and was markedly higher than that using the resting cells. The absorption peak of the suspension of gold particles was also investigated to clarify the size and morphology of the prepared gold particles.