May 8, 2002
Electricity aids drug delivery down nanochannels
Scientists at Ohio State University, US, have modelled the flow of fluid down narrow channels that are under the influence of an electric field. The ultimate aim of the work is to aid drug delivery from tiny devices inside the body.
"Pushing fluid through a very small channel requires a lot of pressure," said Terry Conlisk, professor of mechanical engineering at Ohio State. "Of course, you can't use pressures like that inside the body. So if we can drive fluid safely and effectively with electricity instead of pressure, that's a real advantage."
The Ohio team modelled a charged fluid that travels down a channel that has a like charge applied to its inner surfaces. The repulsion between the like charges causes the fluid to flow down the channel.
Although that basic principle has been around for a long time, the team claims that its research has been more broad in scope than other work. "Other research has involved purely theoretical or purely experimental work, but our approach combines both, for channels in a wide range of sizes," said Derek Hansford, also of Ohio State.
The model was tested using actual nanometre-sized channels at iMEDD, a company that specializes in drug delivery and was co-founded by Mauro Ferrari, director of Ohio State's Biomedical Engineering Center. The iMEDD scientists drove saline through narrow channels using electric potentials as low as 1 V. A 7 nm wide channel transported nearly 0.5 nl of saline per minute, while a 20 nm channel achieved a flow rate of nearly 0.8 nl/min. The computer model closely matched these experimental results.
The Ohio team says that the electric charges would not be dangerous to a patient because they are small and would flow only along the channels inside the device. In the long term the research could help the development of drug-delivery devices that target disease sites in the body, such as tumours.
The scientists reported their work in Analytical Chemistry.
About the author
Liz Kalaugher is editor of nanotechweb.org.