Nanotech News

October 17, 2005

Two Papers Explore Nanoparticle Safety

A major focus of the NCI Alliance for Nanotechnology in Cancer is developing the standards and methods needed to ensure that nanomaterials are safe for use in humans, and that products designed for clinical use have a well-defined pathway to follow in the regulatory approval process. To this end, the NCI established the Nanotechnology Characterization Laboratory, which over the past year has developed a wide-ranging set of assays for screening nanomaterials and identifying potential toxicities associated with a given nanomaterial. Now, a report from the International Life Sciences Institute (ILSI) in Washington, DC suggests strongly that the NCL is taking the right approach to the problem of ensuring that nanomaterials designed for biomedical applications are safe for human use.

The report, which was published in the journal Particle and Fibre Toxicology, did not specifically address biomedical applications of nanotechnology. Rather, the 14-member Nanomaterial Toxicity Screening Working Group, formed in February 2005, was concerned with any nanomaterial that might be used in a commercial application, and thus, be manufactured in large quantities. In contrast, most biomedical applications require small amounts of material.

Nonetheless, the series of assays that the report's authors propose have already been incorporated in the NCL's assay cascade. In particular, the NCL's assay cascade reflects the need to address a major concern, stated in the report, that there is "a strong likelihood that biological activity of nanoparticles will depend on physiochemical parameters not routinely considered in toxicity screening." Both the NCL and the Working Group stress the notion that it is critical to characterize both the biological behavior of nanomaterials and their physical and chemical properties so that the research community can better understand the relationship between a nanomaterial's physical and chemical properties and any potential toxicities.

A second paper, from a multi-institutional group led by Mark Wiesner, Ph.D., at Rice University, suggests that nanomaterial manufacturing is relatively safe compared to other manufacturing processes used today by industry. Relying on methods used by the insurance industry to assess relative risks, the investigators examined manufacturing processes designed to make five different nanoscale materials, including carbon nanotubes, buckyballs and quantum dots, all three of which have potential applications for detecting and treating cancer.

Each manufacturing process was assessed in terms of volatility, carcinogenicity, flammability, toxicity and persistence. The authors conclude from their analysis that there do not appear to be any unusual risks associated with the production of the five nanoscale materials they examined. In fact, the researchers noted that "the fabrication of nanomaterials may present lower risks than those of current activities such as petroleum refining, polyethylene production, and synthetic pharmaceutical production."

The report from the ILSI was published as a paper titled, "Principles for characterizing the potential human health effects from exposure to nanomaterials: elements of a screening strategy." The full-text report is available at the journal's website. View paper.

The assessment of manufacturing risk is detailed in a paper titled, "Relative risk analysis of several manufactured nanomaterials: an insurance industry context." Investigators from Golder Associates (Houston, TX), and XL Insurance (Zurich, Switzerland) participated in this study. This paper was published online prior to print publication. An abstract is available at the journal's website.
View abstract.