Posted: September 24, 2009 |
A flash of light turns graphene into a biosensor |
(Nanowerk News) 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.
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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.
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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.
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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)
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This research was funded by PNNL as part of its Transformational Materials Science Initiative.
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Reference: Zhiwen Tang, Biofunctionalization of Graphene for Biosensing and Imaging, Tuesday, Sept. 22, 2009 Micro Nano Breakthrough Conference, Portland, Ore.
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