The University of Pittsburgh Swanson School of Engineering, the Dietrich School of Arts and Sciences Department of Chemistry and Temple University Department of Chemistry will collaborate on research funded by a grant from the Defense Threat Reduction Agency's (DTRA) Joint Science and Technology Office (JSTO) within the United States Department of Defense. Pitt and Temple researchers will investigate the use of multifunctional metal-organic frameworks (MOFs) with plasmonic cores that can be used to detect and destroy chemical warfare agents and toxic industrial chemicals.
The DTRA funds academic research to find solutions for effective and affordable threat reduction, concentrating on combating weapons of mass destruction. Pitt and Temple researchers will receive a grant for basic research worth $1.5 million over three years with the potential to be increased to $2.5 million over five years.
Principal investigator J. Karl Johnson, Professor of Chemical and Petroleum Engineering, will lead the study by modeling multifunctional MOFs at the atomic scale. The team will design new MOFs that facilitate selective transport of toxic chemicals to a plasmonic nanoparticle core within the MOF, where they can be detected and neutralized.
"What we want to do is produce new hybrid materials that use light to detect chemical warfare agents," said Johnson. "When you shine a light on plasmonic nanoparticles, electrons in the material are excited by the light. We can use these excited electrons to detect chemicals and carry out chemical reactions once the substances are identified."
Nathaniel Rosi, Professor of Chemistry at Pitt, Jill Millstone, Associate Professor of Chemistry at Pitt, and Eric Borguet, Professor of Chemistry at Temple, will join Johnson on the study.
Rosi will lead research into the chemistry of the MOFs and work to design MOFs with stratified layers that direct the chemical warfare agents and toxic industrial chemicals to the plasmonic core.
"The porous MOF contains gradients of functional layers that lead to the plasmonic core. The sponge that's on your kitchen sink has pores, but they are uniform inside and out. The MOFs we are developing have multiple porous layers, and each layer has affinity for different molecules. It would be like having a sponge with a special layer for cleaning up water, another for oil and another for coffee or any other mess in the kitchen," said Rosi.
Another key component of the research will be finding the right substances to make up the plasmonic core. Gold and silver are traditionally used because they exhibit the appropriate oscillating behavior when light is shone on them. However, their expense limits widespread use. Millstone will lead the research into finding other materials to replace gold and silver.
"About 99 percent of the plasmonic materials studied for these technologies have been made with either gold or silver," said Millstone. "But, as promising as the plasmonic properties are, the expense is too high. Our work is to develop new materials from cheaper, earth abundant metals and metal combinations. Each component of this research is novel, and we are very excited to make significant contributions to our fields."
Borguet, in charge of the team at Temple, will direct the sensing and catalytic studies, deploying a suite of techniques to help optimize the response of the materials to specific target analytes.