Imaging gives clues to how nanoparticles attack cancer

In a recently published study, scientists at the Virginia Tech Carilion Research Institute invented a technique for imaging nanoparticle dynamics with atomic resolution as these dynamics occur in a liquid environment. The results will allow the imaging of nanoscale processes, such as the engulfment of nanoparticles into cells.

‘We were stunned to see the large-ranged mobility in such small objects,’ said Deborah Kelly, an assistant professor at the Virginia Tech Carilion Research Institute. ‘We now have a system to watch the behaviours of therapeutic nanoparticles at atomic resolution.’

In the study, Kelly and her colleagues used rod-shaped gold nanoparticles, which are roughly the size of a virus and used to treat various forms of cancer. Once injected, they accumulate in solid tumours. Infrared radiation is then used to heat them and destroy nearby cancerous cells.

To better visualise the gold nanoparticles, the researchers made a vacuum-tight microfluidic chamber by pressing two silicon-nitride semiconductor chips together with a 150nm spacer in between.

The microchips contained transparent windows so the beam from a transmission electron microscope could pass through to create an atomic-scale image.

Using the new technique, the scientists created two types of visualisations. The first included pictures of individual nanoparticles’ atomic structures at 100,000-times magnification, which is claimed to be the highest resolution images ever taken of nanoparticles in a liquid environment. 

The second visualisation was a movie captured at 23,000-times magnification that revealed the movements of a group of nanoparticles reacting to an electron beam, which mimics the effects of the infrared radiation used in cancer therapies.

‘The nanoparticles behaved like grains of sand being concentrated on a beach by crashing waves,’ Kelly said in a statement. ‘We think this behaviour may be related to why the nanoparticles become concentrated in tumours. Our next experiment will be to insert a cancer cell to study the nanoparticles’ therapeutic effects on tumours.’

The team is also testing the resolution of the microfluidic system with other reagents and materials, bringing researchers one step closer to viewing live biological mechanisms in action at the highest levels of resolution possible.

The study appeared in Chemical Communications in an article entitled, Visualizing Nanoparticle Mobility in Liquid at Atomic Resolution.