Challenges Of Risk-Based Nanotech Research

Understanding the environmental health and safety (EHS) implications of engineered nanotechnology is receiving a lot of attention these days. The federal government and other groups are working hard to develop effective EHS research strategies to ensure public safety as more nanotech-containing products make their way to consumers.

One such group is the International Council on Nanotechnology, which is based at Rice University. ICON held a pair of workshops over the past year to get a handle on what research needs to be carried out to develop a predictive model for assessing how nanoparticles will interact with biological systems.

"We need to have good correlations between the physical and chemical properties of nanoparticles and their potential interactions in biological systems and the environment," points out ICON Director Kristen Kulinowski. "The lack of a quantitative framework for understanding those interactions is leaving us in a bind with respect to doing risk assessment," she says.

One key factor that complicates the ability to develop a framework for predicting the interactions of nanoparticles is their variability. "There are just too many types of nanoparticles all under the broad umbrella of nanotechnology to make any blanket statements about their interactions with, say, a cell or tissue," Kulinowski explains.

"Even if we focus on one type of nanoparticle like carbon-based ones, there is still an unbelievable variety of nanostructures that can be created," Kulinowski says. She notes that the way the materials are made also affects their behavior. For example, some carbon nanotubes have been found to contain toxic metals that are left from the catalyst used to produce them, which makes interpretation of toxicity data on the nanoparticles more complicated.

Another factor that makes developing a predictive framework such a challenge is the wide range of EHS research topics being pursued. Kulinoski points out that researchers are working on the nanoparticle du jour instead of taking a systematic look at them and how they might interact in biological settings. She is hoping that the strategies being developed by ICON and other stakeholders can help get researchers moving in a coherent direction.

To that end, Kulinowski tells C&EN that several themes emerged from the ICON workshops and will be the basis for its proposed research strategy. One theme is a "screaming need to link the physical and chemical characteristics of nanoparticles to their interactions with biological systems and the environment, recognizing that once you put a nanoparticle into a complex environment, it will change," she says.????????????????????????

Another cross-cutting theme is the need for standardized assays specifically validated for nanoparticles. Kulinowski notes that this is important because the assumption that the old tools and the old rules apply to nanotechnology is not always valid. In addition, she says, characterized reference materials are essential.

"As a community, we need to make sure we are all doing the same tests on the same materials," she says. "Then we can start to get some reproducibility and quality control so we can compare apples to apples, something that isn't really possible with a lot of the toxicity data coming out."

Kulinowski expects the final ICON document to be out this fall. She adds that she hopes the government will use this report to help augment any strategy that it develops.