Erupting ‘nano-volcanoes’ designed to deliver drugs

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

The thin film is made of a photoreactive material that undergoes a chemical change wherever it has been struck by the light. The researchers then submerged the thin film in a liquid solution that washed away the parts of the film that were exposed to light. The material that remains is shaped like a nanoscale volcano.

‘We can control the pattern of light by changing the diameter of the nanoparticle spheres, or by changing the wavelength – or colour – of the light that we shine through the spheres,’ said Xu Zhang, a doctoral student in mechanical and aerospace engineering at NC State and lead author of a paper describing the work. ‘That means we can control the shape and geometry of these structures, such as how big the cavity of the nano-volcano will be.’