BLACKSBURG, Va., Nov. 19, 2001 — Is soot the newest thing in small tech?
According to scientists at Luna Innovations, the answer is yes. The Blacksburg, Va., research company is experimenting with carbon nanomaterials in buckyballs to develop improved contrast agents for use in magnetic resonance imaging (MRI).
This research could result in MRI scans that require smaller doses of toxic material, cost less and provide physicians with contrast improvements up to 100 times greater than that of existing technology, company researchers say.
Ultimately, they say their research could pave the way for smaller, more affordable MRI instruments while giving equipment manufacturers new markets to tap.
Buckyballs are hollow structures that form when vaporized carbon condenses amid inert gas. Luna Innovations has created buckyballs that encase three atoms of metal. The company starts with carbon rods, drills them and fills them with metal, and places them in an electric arc generator. The resulting soot that’s formed in the generator serves as the mother lode for investigation.
“Our design materials are a certain percentage of that soot. From that soot we extract our valuable material,” said Paige Stevenson, Luna’s director of advanced materials. “But it’s not usable as is: you have to do some chemistry to the cage to make it usable.”
Converting soot into a useful material involves a complex laboratory synthesis. Luna said its chemistry produces materials that are soluble in water and stable in air — two fundamental obstacles that have hampered the commercial use of buckyballs, which were discovered in 1985.
LESS IS MORE, SMALLER IS BETTER
Scientists have tinkered with buckyballs since they were first discovered, trying to insert metal atoms in them. Most efforts met with limited success. Buckyballs showed the ability to carry one or two metal atoms, but the compounds that resulted often were inherently unstable or couldn’t be produced in quantities sufficient for commercial applications.
Luna’s carbon cage resembles a whirring helicopter blade: three metals joined together, with a nitrogen atom in the center. The molecular arrangement may triple the punch of useful properties in the metal, the company said.
“We think this new class of molecules will enable us to encapsulate a wide variety of metals inside the fullerenes cage,” said Steve Stevenson, a Luna senior research scientist who helped discover the fabrication process and the husband of Paige Stevenson.
“With this process we can potentially triple the punch of useful properties in the metal,” he said.
Luna’s first focus is to develop MRI contrast agents that provide enhanced image resolution. Contrast agents provide a clear picture during MRI procedures. Patients are injected with these agents to help physicians diagnose problems or diseases, especially of the brain or spine.
Luna also wants to formulate reagents that enable cell-targeting diagnosis and treatment of certain diseases, especially cancer. The company recently won a two-year federal grant of $2 million to prove the commercial viability of its chemical reagents.
Analysts project the U.S. market for contrast agents will reach $680 million by 2004.
MRI contrast agents usually contain gadolinium, a rare earth metal with magnetic properties. Gadolinium improves the image obtained through an MRI. In sufficient quantities, however, gadolinium can be toxic.
Luna’s scientists stress that existing MRI technology is safe but that their technology does offer improvements by being able to encapsulate gadolinium within the carbon cage. The benefit would be twofold: enhancing the image for physicians while reducing patients’ risk of exposure.
Aside from being able to encapsulate metals inside buckyballs, the company’s research also gives the ability to vary the metals in different combinations, said Paige Stevenson.
Luna’s target is to enhance images 100 times over existing MRI technology. “But even if we’re 50 times better, a lot less material would need to be administered (to MRI patients),” she said. “There also is the chance to send material to direct sites instead of having it travel all through your body, as well as enabling the technology for smaller MRI instrumentation.”
The ability to make MRI devices smaller means they could be used on battlefields or field hospitals. These smaller instruments would require a lower magnetic field, which would eliminate the cost of maintaining huge superconducting magnets.
POTENTIAL SOCIAL BENEFITS PROMISING
Steve Stevenson accidentally discovered the fabrication process along with Harry Dorn, a professor at Virginia Polytechnic Institute and State University in Blacksburg. At the time of the discovery, Stevenson was working for Dorn as a postdoctoral fellow at the university. Luna licensed the process from the university and attempted to build on it.
“Basically that’s where the license ended: just making a pile of soot,” he said.
Luna’s work involved expanding the license to find ways to develop useful materials with productive properties from the soot. Luna’s small team of researchers has devoted a lot of time to making sure any new materials created by its science dissolve in water, a requirement for agents that will be introduced into the human body.
Although the economic potential of their work is enormous, Luna researchers are also mindful of the favorable benefits they could have on society. Gushes Paige Stevenson: “We’re very excited to come to work every day.”