A $465,000 career award from the National Science Foundation is the latest in large-scale support for a Binghamton University chemist who is exploring exciting new research opportunities at the scale of the infinitesimal.
C. J. Zhong, who joined the faculty at Binghamton in 1998, is committed to advancing our understanding of the nanoworld, where structures tens of thousands of times smaller than a human hair behave in ways we are only now learning to predict. His work, which involves fundamental research as well as the development of practical applications, has high-stakes implications in fields as diverse as chemical and biological sensing, information storage, and catalysis.
Catalysis, which is key to everything from the development of fuel cell vehicles to new chemicals, refers to the acceleration of chemical reactions by materials that are chemically unchanged at the end of the reaction. It is involved in more than 80 percent of all chemical processing, and the production of petroleum products is entirely reliant on it. Catalysis saves money by making reactions possible at lower temperatures, with smaller quantities of materials, or by generally reducing the energy requirements, Zhong said.
But researchers are learning in nanoscience that it’s not just a matter of applying what is already known to ever-more miniature systems. The rules of engagement for catalysis in the nanorealm are very different than they are at larger scales. In fact, across the board-sensory, magnetic, electronic, and catalytic properties of nanoscale particles have little or no precedent.
“When you are working at nanoscale, it’s not just that things get smaller, it’s that there are a whole different range of possible outcomes,” Zhong said. “Nanoscale right now is a an entirely new world. At the fundamental level there is a need to better understand the complex electronic, magnetic, sensory and catalytic behaviors of nanoparticles.”
That’s because even the most familiar of compounds behave very differently at nanoscale-or billionth-of-a-meter-proportions. As a prime example, Zhong points to the metal gold, which has long served as a preferred model for research because it is not easily oxidized. Many other metals tend to easily breakdown and degrade during experimentation. Gold, which in bulk form appears yellow, melts at over 1000 degrees C, and generally hasn’t been seen as much of a catalyst in the past.
“That’s why we use it for jewelry,” Zhong joked.
Gold nanoparticles, however, exhibit very different properties from the metal in a more massive state. They melt when heated to only a few hundred degrees C and are proving able catalysts in a broad range of reactions, where they more easily and less expensively lower barriers to important reactions than do more traditional competitors, such as platinum. At nanoscale, even the yellow color from which gold draws its name changes. Gold nanoparticles can appear as red, blue or a wide variety of other colors, depending on their size and spacing from each other, Zhong noted. This characteristic, first capitalized on by ancient artisans who used tiny flakes of gold to colorfully decorate everything from jewelry to vases, today offers great promise in the field of biological sensors, Zhong said.
Since the visible color of gold nanoparticles changes depending on their spacing, if specific DNA strains can be made to hook up with nanoparticles of gold and thereby to change the spacing of the gold particles, the visible color of the gold particles will change. Presuming the sensor is tuned to bind with anthrax DNA, for instance, exposure to anthrax would immediately be signaled by a change in the color of the gold particles in the sensor. This idea actually being pursued by other researchers in the field, Zhong said. That makes it possible to develop gold-particle biosensors that are essentially the nanoparticle equivalent of litmus paper, providing a quick, visible signal to indicate something important about the environment to which they are exposed.
Similarly, by making use of magnetic and electronic properties of specific nanoparticles, which can also be very different from those associated with larger particles of the same substance, important new information storage applications will likely be developed, he said.
Because of the sweeping implications of his work, Zhong enjoys more than $600,000 in funding from sponsors in addition to his NSF career award. Those sponsors include the NSF by means of other awards, the American Chemical Society, the World Gold Council and Honda, for which he conducts research that could prove critical to the development of fuel cell vehicles.
As part of his NSF career award research plan, Zhong expects to develop novel mediator-template pathways as a general strategy for assembling nanoparticles, making it possible to better control the size, shape and interspacial properties of assembled nanoparticles. He also hopes to develop new design parameters in terms of size, shape, and interparticle spatial properties, an approach that will allow for the electrical and binding properties of nanoparticles to be tuned for such specific applications as chemical sensors and biosensors.
But Zhong’s research isn’t the only thing that should be significantly advanced by the NSF career award, which is expected to span the next five years. While the award supports Zhong’s proposed plan to address some of the most pressing problems in nanoparticle assembly in the research lab, it also places strong emphasis on curriculum development.
“Current technology is micron technology and most students are comfortable with that,” he said. “But 10 years down the road, everything will be nanotechnology, and we have to start preparing them to live and work in that world as well. This small stuff is going to be big for a very long time.”
In order to do that, Zhong intends to develop new graduate and undergraduate course modules centered on “nanoscale chemistry,” he said. The educational component will also involve hands-on interdisciplinary activities and outreach to area high schools.
Research and education already go hand-in-hand in Zhong’s laboratory, which includes a research team comprising a senior research scientist, eight graduate students and 10 undergraduate students. Zhong says the enthusiasm they bring to helping to chart the limits and explore the possibilities of the nanoworld is one of his biggest rewards.
