When two scientists were recently awarded the Nobel Prize for physics for their work with graphene, a Kansas State University professor was thrilled with the recognition of the new two-dimensional material.
Vikas Berry, assistant professor of chemical engineering, has spent three years researching graphene, a form of carbon that is only one atom thick. Although his background of study involves gold nanoparticles, Berry was inspired to study graphene after reading research by Andre Geim and Konstantin Novoselov, the two Russian-born scientists who received this year's Nobel Prize for their discovery of graphene and experiments associated with it.
"I was completely fascinated by the expanse of opportunities this new nanomaterial offers," Berry said. "With an atomic width, graphene exhibits exotic physics, and yet it has a large surface area. It's one of the easiest nanomaterials to work with since one can see it under a regular microscope."
Graphene has widespread appeal because of several extraordinary properties it possesses: it has the highest carrier mobility; is the world's strongest nanomaterial; is optically transparent; has a high thermal conductance; and is highly impermeable. Because of these properties, research involving graphene has exploded since its discovery six years ago, Berry said.
"Not too long ago, it was believed that this material would not exist," Berry said. "However, the Nobel laureates proved that it can actually exist in free form, and that one can isolate these as single atom thick crystals."
Since Berry began his graphene research, he has had a few opportunities to discuss his research with Geim. Berry's research with graphene has helped K-State become the first to look into the bio-applications of graphene.
Berry has built DNA sensors and bacteria transistors using graphene. Such research could help K-State become a top 50 public research university by 2025.
Berry and Kabeer Jasuja, a K-State doctoral student in chemical engineering, India, recently researched gold ions and graphene under microwaves. They used a kitchen microwave oven to attach gold nanoparticles to graphene-oxide. The graphene-oxide acted as a stabilizing and supporting agent for the naked gold particles, which then showed strong catalytic activity. Their work appeared in the Journal of Physical Chemistry Letters in June. Josh Linn, senior in chemical engineering, Abilene, and Steven Melton, master's student in electrical engineering, Kansas City, Mo., also participated in this research.
To study the biocompatibility of graphene paper, Berry and Nihar Mohanty, a doctoral student in chemical engineering, India, collaborated with Rodney Ruoff, professor of mechanical engineering at the University of Texas at Austin. Ashvin Nagaraja, a graduate student in electrical engineering, Manhattan, also participated in the research.
"To apply graphene's ultrahigh strength in the biomedical industry, it's important to study graphene's biocompatibility," Berry said. "There are several applications which require materials that are strong and biocompatible."
The researchers combined TWEEN -- a biocompatible compound -- with graphene paper and made an important discovery: Graphene paper was biocompatible in the three cell lines tested and the graphene-TWEEN composite paper inhibited bacterial binding. This showed that ultra-strong graphene papers could be modified to control bio-interfacial properties for medical applications, such as biocompatible knives and implants. The research appeared in Advanced Materials in January.
Berry's research laboratory currently is studying composites of graphene and boron nitride, another two-dimensional research material. While graphene is a highly conductive material, boron nitride is completely insulating, showing that the two materials seem to be complementary, Berry said. So far the researchers have isolated single-atom thick sheets of boron nitride and synthesized their dispersions. They're fabricating electrical devices employing both graphene and boron nitride and are preparing a manuscript for another publication.
"After the two Nobel laureates published their seminal paper, it was very clear that graphene was an extraordinary material," Berry said. "The developments in graphene research have been multiplying ever since."