Nanotechnology-enabled systems offer great promise for solving difficult environmental and biological problems. Their small size, high surface areas, and unique properties all provide opportunity for use-driven science and engineering research. Of focus here is the use of engineered nanoparticles in biological and environmental applications; these two areas that are naturally linked as their materials require control over the “wet/dry” interface between living systems and inorganic materials. This talk will introduce general methods to produce stable and functional nanoparticles which retain their unique properties within complex biological and environmental systems. Ultimately with the appropriate tools we will be able to predict the behavior – the transport, biokinetics and effects – of engineered nanoparticles in natural systems.

The fundamental understanding of the wet/dry interface lays the foundation for using these materials to address societal problems. Quantum dot/metal complexes, for example, can be generated to act as probes in biological systems. When linked with specific peptide sequences, these systems can detect the presence of metalloproteases or MMPs. These elusive biomolecules are thought to be excellent indicators for the biological state of solid tumors, and their application could yield a combination of both structural and functional imaging. In a second example the nanoscale behavior of magnets are the basis for developing point-of-use water purification for arsenic-rich sources. High surface area and monodisperse Fe3O4 nanocrystals will move in very low magnetic field gradients (< 100 T/m) in a size-dependent fashion. The striking size dependence of the magnetic separation process permits the first multiplexed separation of nanocrystals by magnetic field strength. This phenomena makes it possible to demonstrate in one proof-of-principle systems that high specific surface area Fe3O4 nanocrystals can be used in a magnetic separation process to remove arsenic.

For these or other examples of nanotechnology to ultimately improve our quality of life, it is critical to address early the possible unanticipated consequences of nanotechnology's application. This proactive dialog about risk is now a visible hallmark of nanotechnology worldwide, and like any innovation it presents new challenges to both researchers and policymakers alike. This talk will conclude with an example of how these challenges elevate the importance of fundamental science in this area. Through studies of several nanomaterial types it is possible to discern structure-function relationships for nanoparticle impact. Armed with this information, we can propose ways to implement nano-enabled technologies that are ‘safe by design'.