Characterisation of nanomaterials
To assess the safety of nanomaterials, there is first a need to characterise them appropriately. This includes performing measurements on various properties, such as particle size, surface area, and water solubility that may affect their toxicity.
Such characterisation is necessary to ensure that any (eco)toxicological studies performed on the same, or very similar, material can be compared to each other.
Furthermore, risk assessors are keen to obtain these measurements to understand if there are any patterns to the behaviour of nanomaterials that can be predicted based on these physico-chemical parameters. For example, does the toxicity of a specific nanomaterial correlate with its particle size? Is it possible to predict the toxicity of a nanomaterial based on a specific parameter, or more likely a combination of parameters? And which physico-chemical parameters are the most important to measure?
A significant problem with some of the earlier research results on the toxicity of nanomaterials was that the actual nanomaterials used in the studies did not have proper (sufficient) characterisation information. This makes interpreting results, as well as comparing different results difficult. Therefore, a minimum set of characteristics needs to be measured for each nanomaterial before conducting any (eco)toxicity study.
Scientists have made significant progress in this field, and most new studies on nanomaterials include extensive physico-chemical characterisation.