In Vivo Effect of Copper and Silver on Synthesis of Gold Nanoparticles inside Living Plants
2013
Anderson, Christopher W.N. | Bhatti, Saleem M. | Gardea-Torresdey, Jorge | Parsons, Jason
Living plants growing on mine waste were assisted to accumulate gold to a concentration greater than 3500 mg kg–¹ (0.35%) dry weight. Where Au was the only high-density metal present in the soil at high concentration, discrete biogenic nanoparticles of the metal were observed in preparations of shoot and leaf biomass. Where an equal concentration of silver was additionally present, a nanoalloy of Au and Ag was observed. An equal concentration of copper in the soil had no chemical affect on the Au and/or Ag structures synthesized and did not alloy with Au and/or Ag. However, both Cu and Ag reduced the size of Au nanoparticles, and the presence of Cu and/or Ag also limited the extent to which Au was reduced in plant tissues to Au(0). Ash prepared from Au-only plant material had a visible reflectance spectrum indicative of a Au surface plasmon resonance that was not apparent for the Au/Ag biomass. The Au concentration of the plant ash (3.2–7.2%) was of the same order of magnitude as Au reference catalysts. Therefore, biogenic synthesis is proposed as a valid technique to create high concentration Au structures in a carbon matrix. Our data suggest that such biogenic nanoparticles should be tested in a range of environmental and industrial reactions.
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