The November 1, 2007, issue of Environmental Health Perspectives (EHP) includes a research article and meeting report concerning nanomaterials. The research article, entitled “Nanosize Titanium Dioxide Stimulates Reactive Oxygen Species in Brain Microglia and Damages Neurons in Vitro,” describes the in vitro neurotoxicity of P25, a commercially available titanium dioxide nanomaterial. According to the study, P25 appears to be non-toxic to isolated N27 neurons, but stimulates BV2 microglia to produce reactive oxygen species and damages oxidative stress-sensitive neurons in cultures of brain striatum. The meeting report, entitled “Meeting Report: Hazard Assessment for Nanoparticles — Report from an Interdisciplinary Workshop,” presents the findings from a nanotoxicology workshop held on April 6-7, 2006, at the Woodrow Wilson International Center for Scholars. Meeting attendees addressed two questions: what information is needed to understand the human health impact of engineered nanoparticles, and how this information is best obtained.
The abstract of the meeting report states:
To assess hazards of nanoparticles in the near-term, most participants noted the need to use existing in vivo toxicologic tests because of their greater familiarity and interpretability. For all types of toxicology tests, the best measures of nanoparticle dose need to be determined. Most participants agreed that a standard set of nanoparticles should be validated by laboratories worldwide and made available for benchmarking tests of other newly created nanoparticles. The group concluded that a battery of tests should be developed to uncover particularly hazardous properties. Given the large number of diverse materials, most participants favored a tiered approach. Over the long term, research aimed at developing a mechanistic understanding of the numerous characteristics that influence nanoparticle toxicity was deemed essential. Predicting the potential toxicity of emerging nanoparticles will require hypothesis-driven research that elucidates how physicochemical parameters influence toxic effects on biological systems. Research needs should be determined in the context of the current availability of testing methods for nanoscale particles. Finally, the group identified general policy and strategic opportunities to accelerate the development and implementation of testing protocols and ensure that the information generated is translated effectively for all stakeholders.