15 July 2008
Nanomaterials: New technology, old toxicology?
The field of nanotechnology is a fast developing science with trans-disciplinary technologies impacting on cosmetic products, medical devices for drug delivery, gene therapy and corrosion-resistant coatings for materials.
With a lack of current EU safety regulations and adequate safety testing strategies governing nanotechnology, it could spell bad news for animals if increased in vivo testing occurs in efforts to determine the safety of these products.
Nanotechnology describes activities involving structures or objects with at least one dimension being less than 100nm. Despite our exposure to naturally occurring nanoparticles on a daily basis, the surge in manufactured particles and this increased exposure raises health concerns, especially with the potential of nanoparticles to produce reactive oxygen species and consequentially oxidative stress in cells and organs.
Current safety regulations governing substances produced and imported in the EU are set out in the REACH (Registration, Evaluation, Authorisation and Restriction of Chemical Substances) EU chemicals policy. Recently, discussions have been held at the EU level concerning the implementation of REACH with respect to nanomaterials. The situation is complicated principally by the fact that reduction in size to the nanoscale can dramatically alter the physicochemical properties of particles, primarily due to the increased surface-to-volume ratio.
There are yet no paradigms to anticipate the significance of such changes in characteristics, so safety information cannot rely on the toxicological profile of the bulk material (non-nano state). The Royal Society and Royal Academy of Engineering have stated that nanoparticles should be treated as new chemicals from a risk point of view.
A recent EU Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) report on the safety of nanomaterials said that there is insufficient knowledge and data concerning the characterisation, detection and measurement of nanoparticles, their fate in humans and in the environment and all aspects of their health effects and environmental toxicity. In addition to this lack of knowledge, current risk assessment procedures require modifying and some are altogether inadequate. Indeed the uncertainties surrounding the handling and preparation of nanoparticles for testing will further stall developments in this area.
The assessment made by the SCENIHR has suggested that neither animal nor in vitro technologies are currently adequate for the safety assessment of nanomaterials. Pursuing animal toxicity methods could result in a large increase in the use of animals in safety testing to support this rapidly growing industry.
A focus on animal toxicology, which has already produced much non-transferable, irrelevant data is misplaced. There are already human-relevant, high-throughput assays developed in related, modern fields such as particulate matter toxicology, which appear to be applicable to nanotechnology. Indeed, interesting alternatives are already being developed by EU-funded Joint Research Centre projects.
It is of great concern that, despite the lack of safety information and adequate testing procedures, nanoparticles continue to be manufactured and available. A precautionary approach would suggest an immediate moratorium on the commercial production of new nanomaterials until adequate and validated non-animal alternatives are in place for safety testing.