New material has potential to fill many needs
Diamonds and graphite are well known forms of carbon. In 1986, three scientists discovered a third form of carbon and eventually won the Nobel Prize in Chemistry in 1996. The new carbon is a hollow molecule with an even number of carbon atoms, usually 60 or 80, form a ball-shaped cage. Because of its geodesic shape, it was named fullerene after Buckminster Fuller and is also called a buckyball.
Fullerenes were pretty rare, but, by 1989, macroscopic quantities were prepared and scientists worldwide began to try to put atoms inside the hollow molecules.
In September 1999, Virginia Tech Chemistry Professor Harry Dorn reported in Nature that he and his postdoctoral Fellow, Steven Stevenson, had discovered a method for reliably and consistently inserting metal atoms inside of fullerenes, creating a novel family of molecules and the architecture for a new field of chemistry.
Dorn is now the Dr. A.C. Lilly, Jr. Faculty Fellow of Nanoscience and director of the Carbonaceous and Radiolabeled Carbonaceous Nanomaterials Centers in the Department of Chemistry at Virginia Tech.
He called the new material trimetallic nitride template endohedral metallofullerenes (TNT EMFs) because inside of each fullerene are three atoms of metal anchored by an atom of nitrogen in an arrangement that looks like the hood ornament of a Mercedes-Benz.
The invention of TNT molecules was almost accidental. Dorn and colleagues drilled holes in graphite rods, inserted metals, placed them in a sealed chamber, and then burned the rods with an arc welder, just like you see in most metal shops. The result was metal-containing fullerenes and something else with an 1109 readout on the mass spectrometer when the metal was scandium. The “something else” turned out to be nitrogen, and it had entered the equation through leaky lab equipment.
The invasive nitrogen made Dorn's filled fullerenes stable and the process for producing them repeatable using different metals.
Why all the excitement? "Not only is the new molecule unique and beautiful," Dorn said in 1999, "it has many potential applications, depending upon the metals and metal mixtures inserted."
Insert magnetic material for semiconductor and, perhaps, superconductor applications. Insert other metals for fluorescent and other optical properties and to amplify fiber optic applications. Insert radioactive material and use the molecule as a tracer in medical applications, with the carbon cage protecting the radioactive center. Fluorescent and optical tags can also be used as tracers for medical and other applications. The carbon cage can protect materials used as contrast agents in MRI procedures. Quantum computing devices can be created by including atoms that have unpaired electrons or spin active materials.
Most of the subsequent research by Virginia Tech's Dorn Laboratory pursued medical applications.
In 2002, patents based on Dorn's filled fullerenes were licensed to Luna Innovations and produced in Danville, Va., by Luna nanoWorks for such applications as improved diagnostic MRI contrast agents and photovoltaic device components. This facility has been a large contributor to economic development in Southwest Virginia.
In 2005, Virginia Commonwealth University (VCU) and Virginia Tech demonstrated the nanoparticles in novel imaging and drug delivery methods to detect tumors implanted in a rat’s brain. Panos Fatouros, professor and chair of the Division of Radiation Physics and Biology at VCU, and Dorn received $1.1 million from the National Science Foundation and $3.7 million from the National Institutes of Health and the National Cancer Institute to test a functional metal-filled fullerene for targeted diagnosis and therapy of brain tumors.
In 2006, the VCU-Virginia Tech team reported in Radiology magazine the first test results using animals for the new MRI contrast agents based on gadolinium based TNT-EMFs significantly better -- 40 times -- than current commercial MRI agents.
In 2009, the team co-invented a remote control process for filling C80 fullerenes with radioactive material as new cancer therapeutic agents. The research is being funded by the National Cancer Institute. The new device will also allow the production of other kinds of radiolabeled fullerenes, such as to track fullerene nanomaterials in the environment.
So far, eight patents have been issued for filled fullerenes and functionalized fullerenes. Additional patents are pending.
- For more information on this topic, contact Susan Trulove at (540) 231-5646.
Partners with the Dorn Laboratory
Meet two of the many partners who have worked with the Dorn Laboratory in the Virginia Tech Department of Chemistry.
One of the longest partners with the Dorn lab is James Duchamp, the James Earl Copenhaver Professor and chair of the Natural Science Division of Emory & Henry College, who has spent so many summers working with Chemistry Professor Harry Dorn.
Duchamp has co-authored more than 25 publications and book chapters primarily reporting on endohedral metallofullerenes and solid state NMR. But at Emory & Henry, the students know him as a good and accessible teacher.
One former Ph.D. student who had a spat of fame is Erick Iezzi. Many students are co-inventors with Dorn and other faculty members on several patents. But Iezzi caused a buzz in the scientific media when he presented at the April 2002 American Chemical Society meeting about creating water-soluble filled fullerenes.
The ability to attach organic groups to the carbon molecules increased their functionality as medicinal agents. That is, it means they could move through the blood and attach to cells to deliver drugs.
Iezzi received a Graduate Fellowship of $20,000 from the American Chemical Society Division of Organic Chemistry. He graduated in 2003 and now Coating Projects Leader at the Fortune 500 company Science Applications International Corporation.
Catching up with Steven Stevenson
What happened to Harry Dorn's partner on the first breakthrough, Steven Stevenson?
He is now professor of chemistry and nanotechnology at the University of Southern Mississippi, still studying fullerenes with a funded research group, including and NSF Career Award.
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