There is increasing interest in the use of nanomaterials (small particles that measure up to 100 nanometres in diameter) in relation to food and animal feed. The chemical properties of such materials can be different from those at the larger scale, this is because nanomaterials have a relatively larger surface area which can make them more chemically reactive.
In its draft scientific opinion on nanoscience and nanotechnologies in relation to food and feed safety, The European Food Safety Authority (EFSA) drew attention to the gaps that exist in understanding the risks posed by nanomaterials and highlighted the need for more research aimed at understanding how to assess and manage the risks they pose. In 2008, during discussions of the EFSA draft scientific opinion, The Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) expressed disappointment and concern regarding the paucity of basic toxicological data on nanomaterials. The COT stressed that there was an urgent need to obtain toxicological data on a representative selection of nanomaterials.
Human volunteers will be dosed with three particle sizes of titanium dioxide; two will be in the nanoparticle range (10 - 100 nm) and one in the micrometre (µm) range. Urine samples will be collected for at least 36 hours post-dosing in timed collections, blood samples will also be taken at specified times. Volunteers will provide samples for 24 hours prior to dosing to determine background variability of titanium dioxide and will maintain similar diets during the monitoring days of each study. Urine and blood samples will be analysed using mass spectrometry (ICP-MS) and microscopy studies will be undertaken to see if particles of titanium dioxide can be found in the blood and/or urine samples after dosing.
A complementary in vitro study will look at the same particles as used in the human volunteer study as well as an extra nano-sized particle. The Caco–2 cell model will be used to assess the uptake and penetration of the nanomaterials. It will investigate translocation of the test materials across gut epithelia which will address the important question of whether nano-sized particles remain in nano-form during penetration of the gut.