ate complex materials that can meet a wide range of demands. From an environmental scientist’s perspective, there is a need to characterize materials to understand what happens to those materials when they enter the world outside of the laboratory or factory. Although each group is tackling different issues, they are united by a need to characterize the properties and behaviors of complex materials in complex environments.
Ricou was also impressed by the wide range of technologies that are now available for characterizing nanoscale materials. He reiterated the importance of creating a database of technologies, and he stated that instrument vendors should hear more about the challenges facing those who need to better characterize nanomaterials. He would like to see development of the ability to perform spectroscopy on dynamic systems at the nanoscale to better understand how the chemistry of a nanomaterial changes over time, which would benefit many aspects of nanocharacterization.
Richard Conroy said that he came away from the presentations with two questions:
This second question is particularly important from the NIH perspective, because many measurements correlate weakly with outcomes, and thus it is not always clear that the measurements are useful when considering the research that has gone into them. He added that consideration of the question of safety and efficacy is also important, in terms of the comparative effectiveness and safety of nanotechnology-based products versus bulk materials.
Conroy provided a quick overview of some of the funding opportunities at NIH. Part of NIH’s current mission is to bridge the life and physical sciences, and, in that regard, he thought the nanomaterial characterization community would be interested in a number of initiatives. Most of the initiatives are funded by NIBIB or the National Institute of General Medical Sciences (NIGMS), with NIBIB focusing more on the clinical side and NIGMS focusing more on basic research. One new initiative is aimed at applying technologies from the physical sciences to life sciences problems. A significant feature of this initiative, the grant review panel includes experts from both NIH and the National Science Foundation (NSF), with the latter providing a physical science perspective to the NIH review process. A partner initiative aims to translate ideas from the physical sciences into the clinical arena.
Another NIBIB initiative is the bioengineering research partnership program that encourages investigators to form a partnership between the life and physical sciences to translate a concept, technique, or tool from the demonstration to the biomedical application phase. NIBIB also offers fellowships that are designed to create time for mid-career researchers in the physical or quantitative sciences to develop projects in the life sciences.
Conroy said that all of the other NIH institutes have similar initiatives, and NIBIB also supports Small Business Innovation Research (SBIR) grants in the area of bioengineering in nanotechnology.
Characterizing Aggregates—Trading Detail for Utility
Jim Litster said he was amazed by what he heard during the workshop about the ability to measure individual small particles. He added, however, that because the of the nanoparticles in use depends very much on the structures in which they are embedded, there is still a need for techniques that are just as powerful at characterizing the state of dispersion or aggregation. Developing the techniques and instrumentation to attack that problem is the logical next step for the field.
Doug Ray agreed that there is not as much capability in the area of concentrated liquids and solids. He asked, “Is it because it is just really hard and the community is not there yet, or is it because we have elected somehow to not focus in that arena?” He does not know the answer but thinks it is an interesting question to consider.
Mark Barteau added that work in this area might focus on “diagnostic,” meaning that it may not be necessary to know all the details of how nanoparticles behave in a matrix. It might be enough now to characterize these complex according to a certain number of reduced parameters or “lumped” parameters. He is aware of some movement in that direction, but the emphasis on incredible levels of detail and expensive instruments does not match the degree found in nanoscale imaging. He wondered, however, if looking at more complex systems at lower levels of detail that are still diagnostic might be where the field makes the biggest impact. Ray added that the atmospheric sciences are starting to move from a more detailed view to one that reduces the amount of information and creates useable models.
Conroy noted that NIH is interested in where the field is going on this matter. He believes that the relevant question relates to how much detail on specific characteristics is needed to predict biological outcomes. Ricou agreed with this idea but stressed the importance of understanding these systems in fine detail to know what is important when trying to predict relevant behavior.
Chemistry and Stability
Levi Thompson pointed out that many of the particles that were discussed at the workshop are semiconductors and