In order to assess the potential hazards of nanoparticles (NPs) releasing, better knowledge about their toxicity to microbes is required. However, it remains controversial whether NPs could exert particle-specific toxicity. In this study, the toxic impacts of four kinds of rare earth oxides (REO) NPs (La2O3, CeO2, Gd2O3, and Yb2O3) on gram-negative Escherichia coli (E. coli) pBR322 were examined. The results indicate that all the tested NPs possessed cytotoxicity against E. coli. To evaluate the ion-related toxicity of REO NPs, the NPs dissolution in the presence of test organisms was quantitatively measured using X-ray absorption fine structure (XAFS) spectroscopy. Our results suggest that NPs-cell contact could facilitate the dissolution of NPs, and the additional ionic release at the particle-cell interface might result in a substantial increase in the ion-related toxicities towards the test organisms. Therefore, the ion-related toxicity of NPs might be grossly underestimated if the additional dissolution of NPs caused by particle-cell contact was overlooked, further leading to a false interpretation of particle-specific toxicity. To the best of our knowledge, this is the first determination of the total NPs dissolution after particle-cell contact. These findings are helpful to advance mechanistic understanding of the toxicity exerted by dissolvable metal-based NPs.
- Ion-related toxicity
- Particle-cell contact
- X-ray absorption fine spectroscopy
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis