New nanotechnology research from N.C. State University has found a way to store precise amounts of material at the nanoscale – a capability that has the potential applications in drug delivery.

Researchers call their nanostructure a “nano volcano” because of its shape. The structures have precisely measured hollow cores, ideal for storing and delivering a drug. Chih-Hao Chang, an assistant professor of mechanical and aerospace engineering at N.C. State, says the size of the core would allow for controlling the quantity of drug stored in the structure. The size of the opening of the nano volcano could regulate the drug’s release. Just as important, the manufacturing process for these nano structures could apply to large-scale drug production.

“The materials used in this process are relatively inexpensive, and the process can be easily scaled up,” Chang said in a statement. “In addition, we can produce the nano volcanoes in a uniformly patterned array, which may also be useful for controlling drug delivery.”

The research appeared in a paper published online in ACS Nano.

The nano-volcanoes are created by placing spherical, transparent polymer nanoparticles directly onto the flat surface of a thin film. Researchers then shine ultraviolet light through the transparent sphere, which scatters the light and creates a pattern on the thin film.

The thin film, made of a photoreactive material, undergoes a chemical change in the places where it has been struck by the light. Submerging the thin film in a liquid solution washes away the parts of the film that were exposed to light. What remains is a structure shaped like a nanoscale volcano.

The researchers developed a highly accurate computer model that predicts the shape and dimensions of the nano-volcanoes based on the diameter of the nanoscale sphere and the wavelength of light.
Chang’s team is now working to improve its understanding of the release rate from the nano volcanoes, such as how quickly nanoparticles of different sizes will “escape” from nano-volcanoes with different-sized volcano openings.

“That’s essential information for drug-delivery applications,” Chang said.

The research was supported by a NASA Early Career Faculty Award and the National Science Foundation’s ASSIST Engineering Research Center at N.C. State.