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Environmental Factor, January 2012

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Nano Grand Opportunities researchers share findings

By Thaddeus Schug

NIEHS Deputy Director Rick Woychik, Ph.D. chatting with Sri Nadadur, Ph.D.

Nadadur, right, chatted with NIEHS Deputy Director Rick Woychik, Ph.D., during the meeting. Woychik has taken special interest in the nanotechnology programs at NIEHS. (Photo courtesy of Steve McCaw)

James Bonner, Ph.D.

James Bonner, Ph.D., an associate professor in the Department of Environmental and Molecular Toxicology at North Carolina State University, was a leader in developing protocols for the in vivo testing experiments. (Photo courtesy of Steve McCaw)

Andre Nel, M.D., Ph.D.

Andre Nel, M.D., Ph.D., a professor and division chief of NanoMedicine at the University of California, Los Angeles, and his lab contributed to both the in vitro and in vivo round-robin experiments. (Photo courtesy of Steve McCaw)

Members of the NIEHS nanotechnology Grand Opportunities (Nano GO) grant program gathered Dec. 8-9, 2011, in Research Triangle Park, N.C., to update their research efforts on engineered nanomaterials (ENMs). This was the final meeting of the consortium, which began in 2009 with 13 two-year grants funded from the American Recovery and Reinvestment Act. The primary goals of this program were to develop reliable and reproducible methods and models to assess exposure, exposure metrics, and biological response to nanomaterials.

The 13 grantees were brought together into a consortium to facilitate interdisciplinary communication, develop research synergies, and conduct collaborative research projects. Several other NIEHS-funded researchers, with interests in nanotechnology, also joined the consortium and provided valuable experimental input. The Nano GO consortium functions as a framework for grantees to work together toward the common goal of developing methods to achieve greater harmonization of research results for hazard assessment of ENMs.

Sri Nadadur, Ph.D., the meeting organizer and a health scientist administrator at NIEHS who oversees much of the Institute's portfolio on nanomaterials in health and safety, explained, "We have seen a great deal of progress in meeting the overall goals of the consortium. This group of scientists worked through many challenging technical issues that are unique to nanomaterials, to develop protocols and achieve reliable and reproducible experimental results.”

Consortium activities

The Nano GO consortium was an active hub of communication among grantees for the duration of the two-year funding period between 2009 and 2011. The consortium provided frequent opportunities for researchers to interact, as they worked closely together to plan, implement, and troubleshoot both individual and collaborative research projects.

A kickoff meeting in 2009 introduced researchers to the diverse skills and areas of expertise represented by the consortium members, and allowed them to begin planning collaborative projects. Progress meetings in 2010 and 2011 enabled participants to assess preliminary results, and refine their methods to address challenges and inconsistencies.

During this meeting, consortium members shared final results and summarized lessons learned. In between these four in-person meetings, consortium members communicated through frequent conference calls, to share experiences and results, identify problems, and refine methods and protocols.

Round-robin test results

In addition to individual projects, consortium researchers conducted several collaborative research projects. These were structured as a series of round-robin tests, in which similar or identical methods were used to perform in vitro and in vivo tests concurrently at thirteen different laboratories around the country. Researchers worked together to design the overall structure of the tests, identify target ENMs, determine appropriate assays, select cell and animal models, and refine research methods and protocols as the tests proceeded (see text box).

The researchers plan to publish the results from these studies in two separate papers, later this year, in the NIEHS publication Environmental Health Perspectives.

(Thaddeus Schug, Ph.D., is a health scientist in the NIEHS Division of Extramural Research and Training (DERT) and a regular contributor to the Environmental Factor. Prior to joining DERT in 2011, he was a postdoctoral research fellow in the NIEHS Laboratory of Signal Transduction.)

Kent Pinkerton, Ph.D.

Kent Pinkerton, Ph.D., left, led a group of researchers studying the pulmonary effects of ENMs in rats. Nigel Walker, Ph.D., right, is the NTP lead on the nanotechnology safety program. (Photo courtesy of Steve McCaw)

Frank Witzmann, Ph.D., Edward Crandall, M.D., Ph.D., and Galya Orr, Ph.D.

Shown, left to right, consortium members Frank Witzmann, Ph.D., Edward Crandall, M.D., Ph.D., and Galya Orr, Ph.D., participated in meeting discussions. (Photo courtesy of Steve McCaw)

Round-robin testing of ENMs

The consortium chose several well-studied and commercially abundant nanomaterials that also possessed a wide range of physical and chemical properties, including zinc oxide (ZnO); three forms of titanium dioxide (TiO2 P25 sphere, anatase, or angular, sphere, and anatase nanobelt); and three multi-walled carbon nanotubes. The selected ENMs were characterized centrally, to ensure consistency of test materials across all laboratories and provide a shared source of detailed, accurate information about the materials.

In vitro studies were performed at eight laboratories. Two cell viability assays (MTS and LDH) and a pro-inflammation cytokine assay (IL-1b) were used to assess the effects of 24-hour exposure to ZnO, TiO2, and carbon nanotubes on three cell lines.

In vivo studies were performed at seven laboratories, with four using mice and three using rats. Mice were exposed to TiO2 nanomaterials and carbon nanotubes through oropharyngeal, or mid-throat, aspiration. Rats were exposed to TiO2 nanomaterials through intratracheal instillation, administering the ENM in vehicle directly to the lung and bypassing the nasal cavity.

Effects were measured at various time points using total cell numbers, differential cell counting to show effects on neutrophilia, imaging of ENMs in bronchoalveolar lavage cells, histopathology images, total protein levels, and levels of lactate dehydrogenase (LDH), a marker for acute or chronic tissue damage.

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