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Bacterial responses to Cu-doped TiO(2) nanoparticles
Bing Wu1, Rick Huang, Manoranjan Sahu
1Department of Energy, Environmental and Chemical Engineering, One Brookings Drive, Campus Box 1180, Washington University in St. Louis, St. Louis, MO 63130, USA.
The Science of the Total Environment
|November 26, 2009
Summary
Copper-doped titanium dioxide nanoparticles (TiO(2) NPs) showed toxicity to Mycobacterium smegmatis, driven by released copper ions (Cu(2+)). Shewanella oneidensis MR-1 tolerated these NPs by producing extracellular polymeric substances and reducing copper.
Area of Science:
- Environmental Science
- Nanotechnology
- Microbiology
Background:
- Titanium dioxide nanoparticles (TiO(2) NPs) are increasingly used, necessitating toxicity assessments.
- Understanding nanoparticle-bacteria interactions is crucial for environmental risk evaluation.
Purpose of the Study:
- To investigate the toxicity of copper-doped TiO(2) NPs to Mycobacterium smegmatis and Shewanella oneidensis MR-1.
- To elucidate the mechanisms behind NP toxicity and bacterial resistance.
Main Methods:
- Synthesis of 20nm Cu-doped and non-doped TiO(2) NPs using a flame aerosol reactor.
- Exposure of M. smegmatis and S. oneidensis MR-1 to NPs in aqueous cultures.
- Assessment of bacterial growth, cellular damage, and copper ion release.
- Evaluation of bacterial defense mechanisms like EPS production and metal reduction.
Main Results:
- Agglomeration of TiO(2) NPs prevented cellular penetration and damage at tested concentrations.
- Cu-doped TiO(2) NPs significantly inhibited M. smegmatis growth, primarily due to released Cu(2+).
- S. oneidensis MR-1 exhibited tolerance through EPS production and efficient copper reduction, mitigating NP toxicity.
Conclusions:
- The toxicity of Cu-doped TiO(2) NPs is primarily mediated by released Cu(2+).
- S. oneidensis MR-1 possesses robust defense mechanisms against NP and copper toxicity.
- Bacterial remediation capabilities are critical factors in assessing the ecological risks of metal-oxide NPs.
