Ex situ formation of metal selenide quantum dots using bacterially derived selenide precursors

Nanotechnology. 2013 Apr 12;24(14):145603. doi: 10.1088/0957-4484/24/14/145603. Epub 2013 Mar 18.

Abstract

Luminescent quantum dots were synthesized using bacterially derived selenide (Se(II-)) as the precursor. Biogenic Se(II-) was produced by the reduction of Se(IV) by Veillonella atypica and compared directly against borohydride-reduced Se(IV) for the production of glutathione-stabilized CdSe and β-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological Se(II-) formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic Se(II-) included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic Se(II-) is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, 'green' synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism
  • Cadmium Compounds / metabolism
  • Glutathione / metabolism
  • Luminescence
  • Methylmalonyl-CoA Decarboxylase / metabolism
  • Microscopy, Electron, Transmission
  • Nanotechnology
  • Oxidation-Reduction
  • Particle Size
  • Quantum Dots*
  • Selenium Compounds / metabolism*
  • Synchrotrons
  • Veillonella / metabolism
  • X-Ray Absorption Spectroscopy

Substances

  • Bacterial Proteins
  • Cadmium Compounds
  • Selenium Compounds
  • cadmium selenide
  • Methylmalonyl-CoA Decarboxylase
  • Glutathione