Stability, bioavailability, and bacterial toxicity of ZnO and iron-doped ZnO nanoparticles in aquatic media

Li, M., Pokhrel, S., Jin, X., Mädler, L., Damoiseaux, R. and Hoek, E.M.V. (2011) Stability, bioavailability, and bacterial toxicity of ZnO and iron-doped ZnO nanoparticles in aquatic media. Environmental Science and Technology, 45(2), pp. 755-761. (doi: 10.1021/es102266g)

Abstract

The stability and bioavailability of nanoparticles is governed by the interfacial properties that nanoparticles acquire when immersed in a particular aquatic media as well as the type of organism or cell under consideration. Herein, high-throughput screening (HTS) was used to elucidate ZnO nanoparticle stability, bioavailability, and antibacterial mechanisms as a function of iron doping level (in the ZnO nanoparticles), aquatic chemistry, and bacterial cell type. ζ-Potential and aggregation state of dispersed ZnO nanoparticles was strongly influenced by iron doping in addition to electrolyte composition and dissolved organic matter; however, bacterial inactivation by ZnO nanoparticles was most significantly influenced by Zn²⁺ ions dissolution, cell type, and organic matter. Nanoparticle IC50 values determined for Bacillus subtilis and Escherichia coli were on the order of 0.3−0.5 and 15−43 mg/L (as Zn²⁺), while the IC50 for Zn²⁺ tolerant Pseudomonas putida was always >500 mg/L. Tannic acid decreased toxicity of ZnO nanoparticles more than humic, fulvic, and alginic acid, because it complexed the most free Zn²⁺ ions, thereby reducing their bioavailability. These results underscore the complexities and challenges regulators face in assessing potential environmental impacts of nanotechnology; however, the high-throughput and combinatorial methods employed promise to rapidly expand the knowledge base needed to develop an appropriate risk assessment framework.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Jin, Dr Xue
• Authors: Li, M., Pokhrel, S., Jin, X., Mädler, L., Damoiseaux, R., and Hoek, E.M.V.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Environmental Science and Technology
• Journal Abbr.: EST
• Publisher: American Chemical Society
• ISSN: 0013-936X
• ISSN (Online): 1520-5851