Researchers have reported new microscopic observations of SARS-CoV-2, the virus that causes COVID-19. The amazing new observations were possible thanks to a technique known as helium ion microscopy, which had not been used before to study this virus.
The new image shows SARS-CoV-2 on the surface of a monkey kidney cell in the lab. The imaging method allowed researchers to not only see the virus, but also to catch the defense mechanism employed by the infected cell itself. You can see some of the pathogens being bound to the cell membrane. The results are published in the Beilstein Journal of Nanotechnology.
Coronaviruses such as SARS-Cov-2 are only around 100 nanometers in diameter – or 100 billionths of a meter. That’s way below the limit for optical microscopes. Electron microscopes have been employed from the very first weeks of the pandemic to image the virus, but these instruments have certain drawbacks. To conduct electron microscopy, it is necessary to coat the cells in a thin layer of gold, which alters their properties.
Helium ion microscopes don’t have these limitations. They can distinguish things over 400 times smaller than a coronavirus, and since they are not altering cells in any way, they can see how viruses and cells actually interact.
“The study shows that the helium ion microscope is suitable for imaging coronaviruses – so precisely that the interaction between virus and host cell can be observed,” lead author Dr Natalie Frese, a physicist from Bielefeld University, said in a statement.
The helium ion microscopes are a relatively new technology, with the first commercially available one being sold since 2007. They have been employed in materials science and engineering first, but the biomedical field is also catching up. Over the last few years, this approach has been used to study human and animal cells, as well as bacteria and archaea.
Studying virus-cell interaction was the logical next step, as understanding how SARS-CoV-2 interacts with cells post-infection might provide new insight in fighting COVID-19 and improve therapies.
“This method is a significant improvement for imaging the SARS-CoV-2 virus interacting with the infected cell. Helium ion microscopy can help to better understand the infection process in COVID-19 sufferers,” co-author Professor Dr Holger Sudhoff, head physician at the University Clinic for Otolaryngology, Head and Neck Surgery, Medical School OWL at Bielefeld University, added.
Over 100 million people have developed COVID-19 over the last 14 months. While therapies have improved, there is still more to find out about this disease and the virus behind it.