Graphene bolsters battery work, biosensors
September 24, 2009
Scientists from the Department of Energy's Pacific Northwest National Laboratory presented their research at the 2009 Micro Nano Breakthrough Conference in Portland, Ore.
A flash of light turns graphene into a biosensor
Disease diagnosis, toxin detection and more are possible with DNA-graphene nanostructure
Biomedical researchers suspect graphene, a novel nanomaterial made of sheets of single carbon atoms, would be useful in a variety of applications. But no one had studied the interaction between graphene and DNA, the building block of all living things. To learn more, PNNL's Zhiwen Tang, Yuehe Lin and colleagues from both PNNL and Princeton University built nanostructures of graphene and DNA. They attached a fluorescent molecule to the DNA to track the interaction. Tests showed that the fluorescence dimmed significantly when single-stranded DNA rested on graphene, but that double-stranded DNA only darkened slightly — an indication that single-stranded DNA had a stronger interaction with graphene than its double-stranded cousin. The researchers then examined whether they could take advantage of the difference in fluorescence and binding. When they added complementary DNA to single-stranded DNA-graphene structures, they found the fluorescence glowed anew. This suggested the two DNAs intertwined and left the graphene surface as a new molecule.
DNA's ability to turns its fluorescent light switch on and off when near graphene could be used to create a biosensor, the researchers propose. Possible applications for a DNA-graphene biosensor include diagnosing diseases like cancer, detecting toxins in tainted food and detecting pathogens from biological weapons. Other tests also revealed that single-stranded DNA attached to graphene was less prone to being broken down by enzymes, which makes graphene-DNA structures especially stable. This could lead to drug delivery for gene therapy. Tang discussed this research and some of its possible applications in medicine, food safety and biodefense. (Contact: Franny White, 509-375-6904)
This research was funded by PNNL as part of its Transformational Materials Science Initiative.
Reference: Zhiwen Tang, Biofunctionalization of Graphene for Biosensing and Imaging, Tuesday, Sept. 22, 2009 Micro Nano Breakthrough Conference, Portland, Ore.
A splash of graphene improves battery materials
Thin carbon sheets enhance titanium dioxide-based batteries
Researchers would like to develop lithium-ion batteries using titanium dioxide, an inexpensive material. But titanium dioxide on its own doesn't perform well enough to replace the expensive, rare-earth metals or fire-prone carbon-based materials used in today's lithium-ion batteries. To test whether graphene, a good conductor on its own, can help, PNNL's Gary Yang and colleagues added graphene, sheets made up of single carbon atoms, to titanium dioxide. When they compared how well the new combination of electrode materials charged and discharged electric current, the electrodes containing graphene outperformed the standard titanium dioxide by up to three times. Graphene also performed better as an additive than carbon nanotubes. Yang discussed this work and provided an overview of the field of electrical storage materials. (Contact Mary Beckman, 509-375-3688)
This research was funded by PNNL.
Reference: Jun Liu, Multifunctional materials from self-assembly for energy storage, Tuesday, Sept. 22,2009 Micro Nano Breakthrough Conference, Portland, Ore. NOTE: Gary Yang spoke in place of Jun Liu.
Tags: Energy, Fundamental Science, Batteries, Nanoscience, Health Science