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Graphene bolsters battery work, biosensors

Scientists from the Department of Energy's Pacific Northwest National Laboratory presented their research at the 2009 Micro Nano Breakthrough Conference in Portland, Ore.

September 24, 2009 Share This!

  • An illustration of how fluorescent-tagged DNA interacts with functionalized graphene. Both single-stranded DNA (A) and double-stranded DNA (B) are adsorbed onto a graphene surface, but the interaction is stronger with ssDNA, causing the fluorescence on the ssDNA to darken more. C) A complimentary DNA nears the ssDNA and causes the adsorbed ssDNA to detach from the graphene surface. D) DNA adsorbed onto graphene is protected from being broken down

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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

Interdisciplinary teams at Pacific Northwest National Laboratory address many of America's most pressing issues in energy, the environment and national security through advances in basic and applied science. Founded in 1965, PNNL employs 4,300 staff and has an annual budget of more than $1 billion. It is managed by Battelle for the U.S. Department of Energy’s Office of Science. As the single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time. For more information on PNNL, visit the PNNL News Center, or follow PNNL on Facebook, Google+, LinkedIn and Twitter.

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