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Here, we investigate the impact of iron oxide nanoparticles (IONPs) and mesoporous silica-coated iron oxide nanoparticles (msIONPs) on Shewanella oneidensis in an aerobic environment, which is likely the main environment where such nanoparticles will end up after use in consumer products or biomedical applications. Monitoring the viability of S. oneidensis, a model environmental organism, after exposure to the nanoparticles reveals that IONPs promote bacterial survival, while msIONPs do not impact survival. These apparent impacts are correlated with association of the nanoparticles with the bacterial membrane, as revealed by TEM and ICP-MS studies, and upregulation of membrane-associated genes. However, similar survival in bacteria was observed when exposed to equivalent concentrations of released ions from each nanomaterial, indicating that aqueous nanoparticle transformations are responsible for the observed changes in bacterial viability. Therefore, this work demonstrates that a simple mesoporous silica coating can control the dissolution of the IONP core by greatly reducing the amount of released iron ions, making msIONPs a more sustainable option to reduce perturbations to the ecosystem upon release of nanoparticles into the environment.
Bibliographical noteFunding Information:
This work was supported by the National Science Foundation under the Center for Sustainable Nanotechnology, CHE-1503408 . The CSN is part of the Centers for Chemical Innovation Program. J.T.B. acknowledges support by a National Science Foundation Graduate Research Fellowship (grant number 00039202 ). TEM imaging in this study was carried out in the Characterization Facility, University of Minnesota , which receives partial support from the National Science Foundation through the MRSEC program. The authors are grateful to Fang Zhou at the Characterization Facility for microtome preparation of resin-embedded samples for TEM. The authors gratefully acknowledge Elizabeth Lundstrom for ICP-MS analysis of the NP binding samples as well as the iron dissolution samples as part of the University of Minnesota Earth Sciences Department. The authors thank Dr. Erin Carlson for use of her iQ5 real-time PCR detection system.
- Gene expression
- Iron oxide
How much support was provided by MRSEC?
Reporting period for MRSEC
- Period 6
PubMed: MeSH publication types
- Journal Article