Researchers at North Carolina State University have come up with a
technique to embed needle-like carbon nanofibers in an elastic membrane,
creating a flexible “bed of nails” on the nanoscale that opens the door
to development of new drug-delivery systems.
The research community is interested in finding new ways to deliver
precise doses of drugs to specific targets, such as regions of the
brain. One idea is to create balloons embedded with nanoscale spikes
that are coated with the relevant drug. Theoretically, the deflated
balloon could be inserted into the target area and then inflated,
allowing the spikes on the balloon’s surface to pierce the surrounding
cell walls and deliver the drug. The balloon could then be deflated and
But to test this concept, researchers first needed to develop an elastic
material that is embedded with these aligned, nanoscale needles. That’s
where the NC State research team came in.
“We have now developed a way of embedding carbon nanofibers in an
elastic silicone membrane and ensuring that the nanofibers are both
perpendicular to the membrane’s surface and sturdy enough to impale
cells,” says Dr. Anatoli Melechko, an associate professor of materials
science and engineering at NC State and co-author of a paper on the work.
The researchers first “grew” the nanofibers on an aluminum bed, or
substrate. They then added a drop of liquid silicone polymer. The
polymer, nanofibers and substrate were then spun, so that centrifugal
force spread the liquid polymer in a thin layer between the nanofibers –
allowing the nanofibers to stick out above the surface. The polymer was
then “cured,” turning the liquid polymer into a solid, elastic membrane.
Researchers then dissolved the aluminum substrate, leaving the membrane
embedded with the carbon nanofibers “needles.”
“This technique is relatively easy and inexpensive,” says Melechko, “so
we are hoping this development will facilitate new research on targeted
The paper, “Transfer of Vertically Aligned Carbon Nanofibers to
Polydimethylsiloxane (PDMS) while Maintaining their Alignment and
Impalefection Functionality”, is published online in the journal /ACS
Applied Materials & Interfaces/. Lead authors on the paper are Ryan
Pearce, a Ph.D. student at NC State, and Justin Railsback, a former NC
State student now pursuing a Ph.D. at Northwestern University.
Co-authors are Melechko; Dr. Joseph Tracy, an assistant professor of
materials science and engineering at NC State; Bryan Anderson and Mehmet
Sarac, Ph.D. students at NC State; and Timothy McKnight of Oak Ridge
The research was supported by the National Science Foundation and the
Department of Defense, Defense Threat Reduction Agency.