Safety in the nano sphere – The safety of nanotechnology is high on the scientific and political agenda. Qualifying and quantifying the issues remains difficult. An Italia team has now devised and tested what they describe as a "systematic and reproducible evaluation of nanoparticle toxicology in living systems". Their approach is based on a physical assessment and quantification of the toxic effects of nanoparticles (NPs). Andrew Maynard, Director, University of Michigan Risk Science Center, in the USA, points out that, "It remains unclear what the results mean for human exposure to engineered nanoparticles, or what the basis might be for deciding relative levels of potential toxicity". He adds that "It is even less clear how their results relate to inhalation exposure to nanoparticles, where a suite of inhalation-specific mechanisms may lead to very different results to those predicted by fruit flies eating the material." An interesting development but perhaps not quite the last word on nano safety.