Efforts by Brown scientists to improve the structure of carbon nanotubes used to deliver drugs and repair cells may help cure central nervous system disorders such as epilepsy and Parkinson's disease.
The findings, set to be published in the journal Biomaterials next month, builds on previous research suggesting that these cylindrical molecules could harm cells in the repair process, according to Loren Jakubek GS, who spearheaded the research project.
Jakubek, an engineering student, hypothesized that changing the structure of the nanotubes could eliminate the problem. She presented her theory to Professor of Neuroscience Diane Lipscombe, who said she "wasn't convinced by the initial hypothesis" but gave Jakubek a chance to work in her lab.
The research team, which began the project in 2008, included Jakubek, Lipscombe, Xinyuan Liu GS and Spiro Marangoudakis GS. The researchers hail from multiple departments, including neuroscience, biology-medicine and chemistry.
Carbon nanotubes have many applications, Jakubek said, but the researchers specifically studied their ability to deliver drugs to the nervous system and provide scaffolding for degenerating neurons.
"Because they're so small and because they're made of carbon," Lipscombe explained, "people thought (carbon nanotubes) would be a great way to deliver medicine to certain parts of the body."
The initial problem with carbon nanotubes seemed to be that they interfered with synaptic transmission — the process neurons use to electrically communicate with one another, Lipscombe said. Medical literature on the subject indicated that nanotubes interfered with channels that allow calcium into a cell, she added.
But the researchers' studies on how nanotubes affect calcium channels produced surprising conclusions.
They discovered that the metals yttrium and nickel, which are used in cell synthesis — and not the structure of the nanotubes — were actually responsible for interfering with communication between cells, Jakubek said.
"Yttrium released from a carbon nanotube can inhibit the ion channel," said Liu, who created a chemical environment similar to a neural membrane to examine the nanotubes' interactions with yttrium and nickel.
Since the team's investigations suggest that the yttrium and nickel trapped inside nanotubes cause ion channel disruption, Jakubek said, nanotubes "can still be applicable once you eliminate these metals."
The high-pressure carbon monoxide process, which uses iron to synthesize nanotubes, seems to eliminate the risks posed by these ions, Jakubek said.
Jakubek said she plans to continue her research by investigating the potential for other nanomaterials to replace nanotubes.
Given the success of this research, by scholars who span several disciplines, the researchers hope the project will inspire more collaboration among the University's science departments.
"Any environment that encourages that type of work is fantastic," Lipscombe said.
