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Dispersion stability of nanoparticles in ecotoxicological investigations: the need for adequate measurement tools.

Tantra, R; Jing, S H; Pichaimuthu, S K; Walker, N*; Noble, J E; Hackley, V A* (2011) Dispersion stability of nanoparticles in ecotoxicological investigations: the need for adequate measurement tools. J. Nanoparticle Res., 13 (9). pp. 3765-3780.

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One of the main challenges in nanoecotoxicological investigations is in the selection of the most suitable measurement methods and protocols for nanoparticle characterisation. Several parameters have been identified as being important as they govern nanotoxicological activity, with some parameters being better defined than others. For example, as a parameter, there is some ambiguity as to how to measure dispersion stability in the context ecotoxicological investigations and in particular to identify tools that can give the best technical indicator for this. The purpose of this paper is to use various commercially available tools to measure dispersion stability and to understand the information given by each tool. By understanding the inherent strength and limitations of various techniques, we can thus identify suitable tools that yield complementary information. In this study, CeO2 was dispersed in two different types of media: de-ionised water and fish media. Stability of these dispersions was monitored using various techniques, for a period of three-days. A visual sedimentation experiment showed that dispersion made in the fish media is less stable compared to corresponding dispersion in de-ionised water. Techniques employed were shown to be sufficiently sensitive to differentiate the two-nanoparticle dispersions; this is true apart from using (Nanoparticle Tracking Analysis) NTA to monitor particle size. Monitoring particle size through NTA method is limited by its inability to accurately track the motion of micron size particles found in the fish media; the presence of large aggregates were shown from Scanning Electron Microscopy analysis. Results show methods should be chosen on the basis that they provide complementary information. Suitable methods to assess dispersion stability should include the assessment of: a) sedimentations events, in which the NTA method was shown to successfully monitor net particle number concentration in the dispersion b) surface charge (and subsequent influence on surface chemistry), which can be monitored by performing zeta-potential measurements c) aggregation events, in which the onset of aggregation techniques such as Dynamic Light Scattering or spectroscopic based methods (UV-vis and fluorescence) were shown to be suitable.

Item Type: Article
Subjects: Nanoscience
Nanoscience > Surface and Nanoanalysis
Identification number/DOI: 10.1007/s11051-011-0298-y
Last Modified: 02 Feb 2018 13:14
URI: http://eprintspublications.npl.co.uk/id/eprint/5222

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