University researchers, together with scientists from Northwestern University and the Korea Institute of Geoscience and Mineral Resources, have employed a novel method to coat substances with graphene oxide. Their study was published in the journal Nano Letters last month.
Graphene, a two-dimensional sheet one atom thick, is one of the newest nanomaterials. The 2010 Nobel Prize in Physics was awarded for experiments with graphene. Robert Hurt, professor of engineering, described graphene research as a "very competitive field in which people stay up all night."
Due to graphene's transparent and extremely strong nature, previous research has looked into the possibility of using it to cover particles, similar to how plastic wrap covers objects, Hurt said. The researchers placed graphene oxide in an aqueous solution and suspended it with other particles, said Fei Guo GS, an author of the study. They then made tiny droplets out of the solution. After a great deal of heat was applied, the water from these droplets evaporated, crumpling the graphene into a cage around whatever else was suspended in the solution.
"When it dries, graphene wraps around nanoparticles," Hurt explained. Nanoparticles are extremely tiny objects and can be used as cargo carried within the graphene sheets.
More research needs to be conducted to determine possible applications, including studying potential cargo. "Nanoproducts like this are really hard to make, and that hinders their commercialization," Hurt said. The group is still unsure whether the graphene coat is a permanent sack or whether it opens up. If the latter is true, the nanosack can be used to deliver drugs to the body, and if it remains sealed, it can be used to contain toxic agents useful for medical imaging.
"The coolest thing is that they were the first ones to demonstrate ... making (graphene-coated particles) in a very reproducible way. And it seemed like they were able to make them in large quantities, and that's really cool," said Christopher Zangmeister, research scientist at the National Institute of Standards and Technology, who was not involved in the study. But Zangmeister questioned whether the aerosol method could be used to coat the amount of cargo required for drug delivery due to the larger scale.
"When one can synthesize a new material, it is a nice feeling," Guo said.