Bacterial responses to Cu-doped TiO2 nanoparticles

Bing Wu, Rick Huang, Manoranjan Sahu, Xueyang Feng, Pratim Biswas, Yinjie J. Tang

Research output: Contribution to journalArticlepeer-review

112 Scopus citations

Abstract

The toxicity of Cu-doped TiO2 nanoparticles (NPs, 20 nm), synthesized by a flame aerosol reactor, to Mycobacterium smegmatis and Shewanella oneidensis MR-1, is the primary focus of this study. Both doped and non-doped TiO2 NPs (20 nm) tended to agglomerate in the medium solution, and therefore did not penetrate into the cell and damage cellular structures. TiO2 particles (<100 mg/L) did not apparently interfere with the growth of the two species in aqueous cultures. Cu-doped TiO2 NPs (20 mg/L) significantly reduced the M. smegmatis growth rate by three fold, but did not affect S. oneidensis MR-1 growth. The toxicity of Cu-doped TiO2 NPs was driven by the release of Cu2+ from the parent NPs. Compared to equivalent amounts of Cu2+, Cudoped TiO2 NPs exhibited higher levels of toxicity to M. smegmatis (P-value<0.1). Addition of EDTA in the culture appeared to significantly decrease the anti-mycobacterium activity of Cu-doped TiO2 NPs. S. oneidensis MR-1 produced a large amount of extracellular polymeric substances (EPS) under NP stress, especially extracellular protein. Therefore, S. oneidensis MR-1 was able to tolerate a much higher concentration of Cu2+ or Cu-doped TiO2 NPs. S. oneidensis MR-1 also adsorbed NPs on cell surface and enzymatically reduced ionic copper in culture medium with a remediating rate of 61 μg/(literOD600hour) during its early exponential growth phase. Since the metal reducing Shewanella species can efficiently "clean" metal-oxide NPs, the activities of such environmentally relevant bacteria may be an important consideration for evaluating the ecological risk of metal-oxide NPs.

Original languageEnglish (US)
Pages (from-to)1755-1758
Number of pages4
JournalScience of the Total Environment
Volume408
Issue number7
DOIs
StatePublished - 2010
Externally publishedYes

Keywords

  • EDTA
  • EPS
  • Mycobacterium smegmatis
  • Remediate
  • Shewanella oneidensis

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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