Short abstract

Characterization of nanomaterials (NMs) in biological media not only add another novel set of challenges to the field of Toxicology and Environmental Science, but also make the development of a robust legislative framework, particularly challenging.

Project description

Toxicology communities have been increasingly reporting that investigation of ENMs based on mass concentration alone would fail to correctly predict their health effects. Particles number has been proposed as alternative dose metrics for toxicological studies. Very few studies evaluated particle number size distribution (NSD) as dose metrics for toxicological purposes. This is due to limitation in technics and sample preparation methods.

Many of the commonly employed techniques are quite limited when applied to NMs in  biological media due to complex and polydisperse solution matrices, background biological particles and molecules and low particle concentration. Alternatively, method is required to isolate ENPs from tissues and cells, and bring the particles to a state that is measurable by the existing analytical techniques.

The main objective of this project is to expose zebrafish to ENMs, isolate the accumulated particles in liver, gills and brain, and obtain the NSD of the isolated particles. For this purpose, an exposure media will be developed and optimized to assure that zebrafish are continuously exposed to ENMs over the exposure duration. An isolation method based on acid digestion will be developed in order to isolate ENMs from the zebrafish tissues.

Characterization of the ENMs will be carried out using the following techniques:

• Transmission electron microscope (TEM) for imaging the ENMs.  
• Dynamic light scattering for measuring particle hydrodynamic size.
• Cryo-Scanning-EM to picture particle within cells and tissues.
• Inductively coupled plasma mass spectrometry (ICP-MS) to measure particle concentrations and single-particle ICPMS for measuring NSD of the ENMs.

This project will generate new data for scientific communities e.g. Toxicity and Environmental Science, allowing the communities to apply the same approaches for other types of ENMs. The results increase the amount of data available for non-academic organizations, for instance, standardization organizations and regulators.

Leiden university is well equipped with instruments for observation and quantification of ENMs. The Institute of Environmental Science has access to specialized instrumentation in-house or through intensive collaborations on all levels. In addition, the support from internationally recognized researchers will help to complete a successful project.

• bioaccumulation
• ecotoxicology
• nanomaterials

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